3DX TECHNOLOGIES INC
424B4, 1996-12-23
CRUDE PETROLEUM & NATURAL GAS
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<PAGE>
                                2,500,000 SHARES
 
                                                                       [LOGO]
3DX TECHNOLOGIES INC.
- ------------------------------------------
                                  COMMON STOCK
 
    Of the 2,500,000 shares of Common Stock, par value $0.01 per share ("Common
Stock"), of 3DX Technologies Inc., a Delaware corporation (the "Company" or "3DX
Technologies"), offered hereby, 2,400,000 shares are being sold by the Company
and 100,000 shares are being sold by Landmark Graphics Corporation (the "Selling
Stockholder"). See "Principal and Selling Stockholders." Prior to this offering
(the "Offering"), there has been no public market for the Common Stock of the
Company. The initial public offering price is $11 per share. See "Underwriting"
for information relating to the factors considered in determining the initial
public offering price. The Company will not receive any proceeds from the sale
of Common Stock by the Selling Stockholder.
 
    SEE "RISK FACTORS" BEGINNING ON PAGE 9 FOR A DISCUSSION OF CERTAIN FACTORS
THAT SHOULD BE CONSIDERED BY PROSPECTIVE PURCHASERS OF THE SHARES OF COMMON
STOCK OFFERED HEREBY.
 
                             ---------------------
 
    The shares of Common Stock have been approved for quotation on the Nasdaq
National Market under the symbol "TDXT," subject to official notice of issuance.
 
                           --------------------------
 
THESE SECURITIES HAVE NOT BEEN APPROVED OR DISAPPROVED BY THE SECURITIES AND
  EXCHANGE COMMISSION OR ANY STATE SECURITIES COMMISSION NOR HAS THE
    SECURITIES AND EXCHANGE COMMISSION OR ANY STATE SECURITIES COMMISSION
      PASSED UPON THE ACCURACY OR ADEQUACY OF THIS PROSPECTUS. ANY
             REPRESENTATION TO THE CONTRARY IS A CRIMINAL OFFENSE.
 
<TABLE>
<CAPTION>
                       PRICE            UNDERWRITING          PROCEEDS TO          PROCEEDS TO
                     TO PUBLIC          DISCOUNT (1)          COMPANY (2)      SELLING STOCKHOLDER
<S>             <C>                  <C>                  <C>                  <C>
Per Share.....        $11.00                $0.77               $10.23               $10.23
Total (3).....      $27,500,000          $1,925,000           $24,552,000          $1,023,000
</TABLE>
 
(1) The Company and the Selling Stockholder have agreed to indemnify the
    Underwriters against certain liabilities, including liabilities under the
    Securities Act of 1933, as amended (the "Securities Act"). See
    "Underwriting."
 
(2) Before deducting Offering expenses payable by the Company estimated to be
    $775,000.
 
(3) The Company has granted the Underwriters a 30-day option to purchase up to
    an aggregate of 375,000 additional shares of Common Stock, at the Price to
    Public, less the Underwriting Discount, solely to cover over-allotments, if
    any. If the Underwriters exercise such option in full, the total Price to
    Public, Underwriting Discount and Proceeds to Company and Proceeds to the
    Selling Stockholder will be $31,625,000, $2,213,750, $28,388,250 and
    $1,023,000, respectively. See "Underwriting."
 
                           --------------------------
 
    The shares of Common Stock are offered subject to receipt and acceptance by
the Underwriters, to prior sale and to the Underwriters' right to reject any
order in whole or in part and to withdraw, cancel or modify the offer without
notice. It is expected that delivery of the shares of Common Stock will be made
at the office of Howard, Weil, Labouisse, Friedrichs Incorporated, Energy
Centre, 1100 Poydras Street, Suite 3500, New Orleans, Louisiana, or through the
facilities of The Depository Trust Company, on or about December 26, 1996.
 
                           --------------------------
 
HOWARD, WEIL, LABOUISSE, FRIEDRICHS  PETRIE PARKMAN & CO.
 
                    INCORPORATED
 
               The date of this Prospectus is December 19, 1996.
<PAGE>
                            ------------------------
 
    IN CONNECTION WITH THE OFFERING, THE UNDERWRITERS MAY OVER-ALLOT OR EFFECT
TRANSACTIONS WHICH STABILIZE OR MAINTAIN THE MARKET PRICE OF THE COMMON STOCK OF
THE COMPANY AT A LEVEL ABOVE THAT WHICH MIGHT OTHERWISE PREVAIL IN THE OPEN
MARKET. SUCH TRANSACTIONS MAY BE EFFECTED ON THE NASDAQ NATIONAL MARKET, IN THE
OVER-THE-COUNTER MARKET OR OTHERWISE. SUCH STABILIZING, IF COMMENCED, MAY BE
DISCONTINUED AT ANY TIME.
<PAGE>
                               PROSPECTUS SUMMARY
 
    THE FOLLOWING SUMMARY IS QUALIFIED IN ITS ENTIRETY BY AND SHOULD BE READ IN
CONJUNCTION WITH THE MORE DETAILED INFORMATION AND FINANCIAL STATEMENTS OF THE
COMPANY AND THE NOTES THERETO APPEARING ELSEWHERE IN THIS PROSPECTUS. EXCEPT AS
OTHERWISE INDICATED, ALL INFORMATION IN THIS PROSPECTUS ASSUMES THE
UNDERWRITERS' OVER-ALLOTMENT OPTION IS NOT EXERCISED AND GIVES EFFECT TO A
REVERSE SPLIT (THE "REVERSE SPLIT") OF THE COMMON STOCK AT A RATIO OF 0.517-TO-1
TO BE EFFECTED IMMEDIATELY PRIOR TO THE CONSUMMATION OF THE OFFERING. SEE THE
"GLOSSARY OF CERTAIN OIL AND GAS TERMS" APPEARING ELSEWHERE HEREIN FOR
DEFINITIONS OF CERTAIN TERMS USED IN THIS PROSPECTUS. INVESTORS SHOULD CAREFULLY
CONSIDER THE INFORMATION SET FORTH UNDER THE CAPTION "RISK FACTORS."
 
                                  THE COMPANY
 
    3DX Technologies is a knowledge-based oil and gas exploration company whose
core competence and strategic focus is the utilization of 3-D seismic imaging
and other advanced technologies in the search for commercial quantities of
hydrocarbons. The Company only enters into arrangements that enable it to
combine its expertise and exploration capabilities with the operating skills of
other oil and gas companies. The Company participates in carefully selected
exploration projects as a non-operating, working interest owner, sharing both
risks and rewards with its partners. The Company commenced operations in January
1993 to take advantage of perceived opportunities emerging from changes in the
domestic oil and gas industry, including the divestiture of domestic oil and gas
properties, advances in technology and the outsourcing of specialized technical
capabilities. By reducing drilling risk through 3-D imaging and analysis, the
Company seeks to improve the expected return on investment in its oil and gas
projects.
 
    The Company has developed a rigorous screening process that it applies to
all projects that it considers. The screening process, which is adapted
continually to incorporate the Company's ongoing experience, is designed to
produce a balanced portfolio of projects that have reliable and experienced
operating partners, are conducive to the application of advanced 3-D technology,
have significant upside potential and may be extended into exploration trends.
 
    As of the date of this Prospectus, the Company's current portfolio includes
12 active operator partners and 24 exploration projects, primarily located
onshore and near shore within the Gulf Coast region from South Texas to Southern
Florida. Although the Company's current geographic focus is principally the Gulf
Coast region, the Company has and will continue to pursue opportunities that may
become available in other select geographic areas as its capital resources
increase.
 
    The Company believes that it can effectively and efficiently participate in
an increasing number of concurrent projects by continually improving its
techniques for acquiring and analyzing data. One example of such an improvement
is the Company's 3DXPRESS process, an innovative exploration technique that
improves the quality of seismic data and significantly compresses the time frame
traditionally required for acquisition, processing, imaging and analysis. This
process allows analysis of 3-D data while the seismic survey is being conducted,
giving the Company's explorationists the ability to ensure data quality and to
steer data collection toward more promising prospective areas. Utilizing this
technology, the Company has been able to image and analyze an increased number
of projects concurrently and to identify potential drilling sites more rapidly
and accurately.
 
    Since its formation through the date of this Prospectus, the Company has
participated in the drilling of 32 gross wells that have been drilled based on
the Company's site and target depth recommendations. Twenty of these wells were
successful and discovered estimated proved reserves of 40.3 Bcfe (2.8 Bcfe net
to the Company's interest), of which 27.0 Bcfe (2.1 Bcfe net to the Company's
interest) were discovered during the first nine months of 1996. The Company
currently expects to participate in the drilling of between 35 and 40 wells
during 1997, although the number of wells may increase as additional projects
are added to the Company's portfolio. The Company believes that the disciplined
approach it utilizes to select its partners and projects, together with its
technological expertise, will result in improved exploration success and project
economics. This success should position the Company to acquire larger working
interests in an increased number of exploration projects.
 
                                       3
<PAGE>
                                  THE OFFERING
 
<TABLE>
<S>                                 <C>
Shares of Common Stock Offered:
  By the Company (1)..............  2,400,000
  By the Selling Stockholder......  100,000
      Total.......................  2,500,000
Shares of Common
  Stock Outstanding (1)(2):
  Before the Offering.............  4,505,049
  After the Offering..............  6,905,049
 
Use of proceeds...................  The net proceeds of the shares of Common Stock sold in
                                    the Offering by the Company, estimated to be
                                    approximately $23.8 million (approximately $27.6 million
                                    if the Underwriters' over-allotment option is exercised
                                    in full), will be used by the Company for (i) capital
                                    expenditures to fund the Company's exploration and
                                    development program; (ii) redemption of all of the
                                    issued and outstanding shares of the Company's
                                    Redeemable Preferred Stock, Series B, $0.01 par value
                                    per share (the "Series B Preferred Stock") and payment
                                    of all accrued but unpaid dividends on the Company's
                                    Senior Redeemable Convertible Preferred Stock, Series C,
                                    $0.01 par value per share (the "Series C Preferred
                                    Stock") prior to the conversion thereof; and (iii)
                                    general corporate purposes including expenses associated
                                    with hiring additional personnel. See "Use of Proceeds."
 
Nasdaq National Market symbol.....  TDXT
</TABLE>
 
- ------------------------
 
(1) Excludes 375,000 shares of Common Stock subject to issuance pursuant to the
    over-allotment option granted to the Underwriters. See "Underwriting."
 
(2) Gives effect to the Transactions defined below, but excludes 1,501,813
    shares of Common Stock reserved for issuance upon exercise of stock options
    which may be granted under the 1994 Stock Option Plan, as amended (the
    "Stock Option Plan"), of which options to purchase 794,479 shares of Common
    Stock, exercisable at prices ranging from $0.19 to $11.20 per share, have
    been granted and are outstanding as of the date hereof. See
    "Management--Stock Option Plan."
 
                                       4
<PAGE>
                                THE TRANSACTIONS
 
    The following transactions (collectively, the "Transactions") will be
effected in connection with the consummation of the Offering: (i) the exercise
of each of the 266,224 shares of Series C Preferred Stock issuable upon exercise
of certain outstanding warrants (the "Series C Preferred Stock Warrants") at a
price of $3.00 per share, (ii) the conversion of each of the then outstanding
2,928,465 shares of Series C Preferred Stock (consisting of the 2,662,241 shares
of Series C Preferred Stock issued and outstanding as of the date of this
Prospectus and the 266,224 shares to become outstanding upon exercise of the
Series C Preferred Stock Warrant) into 1,514,017 shares of common stock (giving
effect to the Reverse Split), with a total recorded value of $8,711,040
(consisting of the September 30, 1996 book value of the outstanding Series C
Preferred Stock of $7,912,368 plus the gross proceeds of $798,672 from exercise
of the Series C Preferred Stock Warrant), (iii) the redemption immediately after
the closing of this Offering of all issued and outstanding shares of the Series
B Preferred Stock (including the effects of a $376,676 redemption premium which
adjusts the Series B Preferred Stock carrying value to the liquidation price of
$100 per share), and (iv) the payment immediately after the closing of this
Offering of Series C Preferred Stock dividends currently accrued on the
September 30, 1996 balance sheet of $780,423. See "Risk Factors-- Benefits of
the Offering to Existing Stockholders." For the pro forma effects of these
Transactions on the Company's balance sheet as of September 30, 1996 see the
"Prospectus Summary--Summary Historical Financial Data," "Capitalization,"
"Selected Financial Data," and the Company's Financial Statements.
 
                                       5
<PAGE>
                       SUMMARY HISTORICAL FINANCIAL DATA
 
    The financial information set forth below for the period from inception of
operations (January 6, 1993) through December 31, 1993 and for the years ended
December 31, 1994 and 1995 is derived from the Financial Statements of the
Company, which were audited by Arthur Andersen LLP. The financial information
set forth below as of September 30, 1996 and for the nine month periods ended
September 30, 1995 and 1996 is derived from unaudited financial statements of
the Company which, in the opinion of management, include all adjustments
necessary for a fair presentation of the financial condition and results of
operations of the Company for such periods. The results of operations for
interim periods are not necessarily indicative of a full year's operations. This
information should be read in conjunction with "Management's Discussion and
Analysis of Financial Condition and Results of Operations," the Financial
Statements of the Company, the notes related thereto and the other financial
data included elsewhere in this Prospectus.
 
<TABLE>
<CAPTION>
                                          PERIOD
                                           FROM
                                        INCEPTION
                                            OF
                                        OPERATIONS
                                         (JANUARY
                                         6, 1993)    YEAR ENDED DECEMBER      NINE MONTH PERIODS
                                         THROUGH             31,             ENDED SEPTEMBER 30,
                                         DECEMBER   ----------------------  ----------------------
                                         31, 1993      1994        1995        1995        1996
                                        ----------  ----------  ----------  ----------  ----------
                                                                                 (UNAUDITED)
<S>                                     <C>         <C>         <C>         <C>         <C>
STATEMENTS OF OPERATIONS DATA:
Revenues:
  Oil and gas.........................  $ --        $  303,836  $  274,511  $  202,185  $  408,459
  Rental income.......................  127,034        100,962      58,195      45,563     120,098
  Interest and other..................    7,528         52,817     236,186     125,549     217,678
                                        ----------  ----------  ----------  ----------  ----------
    Total revenues....................  134,562        457,615     568,892     373,297     746,235
 
Costs and expenses:
  Lease operating.....................    --            14,225      60,877      31,443      28,463
  Production taxes....................    --            19,812      17,656      12,380      22,764
  Impairment of oil and gas
    properties........................    --            --       1,627,321   1,477,567   1,476,690
  Depletion, depreciation &
    amortization......................   65,368        210,347     446,350     287,933     463,573
  General and administrative..........  596,267        598,244     905,063     652,671   1,343,660
  Interest and other..................   88,006         --          --          --             289
                                        ----------  ----------  ----------  ----------  ----------
    Total costs and expenses..........  749,641        842,628   3,057,267   2,461,994   3,335,439
                                        ----------  ----------  ----------  ----------  ----------
Net loss from continuing operations...  (615,079  )   (385,013) (2,488,375) (2,088,697) (2,589,204)
Dividends on preferred stock..........  (52,790   )   (421,696) (1,058,956)   (113,257)   (505,167)
Accretion on preferred stock..........  (14,353   )    (30,367)    (48,408)    (34,681)    (41,133)
                                        ----------  ----------  ----------  ----------  ----------
Net loss from continuing operations
  applicable to common stockholders...  $(682,222 ) $ (837,076) $(3,595,739) $(2,236,635) $(3,135,504)
                                        ----------  ----------  ----------  ----------  ----------
                                        ----------  ----------  ----------  ----------  ----------
Pro forma net loss from continuing
  operations applicable to common
  stockholders (unaudited) (1)........                          $(2,488,375)            $(2,589,204)
                                                                ----------              ----------
 
Pro forma primary and fully diluted
  net loss from continuing operations
  per share (unaudited)...............                          $    (0.47)             $    (0.49)
                                                                ----------              ----------
 
Pro forma weighted average number of
  common shares outstanding
  (unaudited) (2).....................                           5,335,982               5,337,553
                                                                ----------              ----------
</TABLE>
 
                                       6
<PAGE>
 
<TABLE>
<CAPTION>
                                                                         SEPTEMBER 30, 1996
                                                        -----------------------------------------------------
                                                                             (UNAUDITED)
                                                                     PRO FORMA                AS ADJUSTED FOR
                                                          ACTUAL    ADJUSTMENTS   PRO FORMA    OFFERING (6)
                                                        ----------  -----------  -----------  ---------------
<S>                                                     <C>         <C>          <C>          <C>
BALANCE SHEET DATA:
  Working capital.....................................  $3,435,650   $ 798,672(3)  $4,234,322   $20,543,799
  Property and equipment, net.........................   4,852,759      --        4,852,759       4,852,759
  Total assets........................................   8,994,140     798,672(3)  9,792,812     26,102,289
  Long-term debt......................................      --          --           --             --
  Accrued dividends...................................     780,423      --          780,423         --
  Mandatorily redeemable Series B preferred stock.....   6,310,424     376,676(5)  6,687,100        --
  Mandatorily redeemable Series C preferred stock.....   7,912,368  (7,912,368)(4)     --           --
  Common Stockholders' (deficit) equity...............  $(6,704,515)  $8,334,364(3    (5)  $1,629,849   $25,406,849
</TABLE>
 
- ------------------------------
 
(1) Adjusted to eliminate dividends and accretion on the Series B Preferred
    Stock and Series C Preferred Stock as if the shares of Series B Preferred
    Stock had been redeemed and the shares of Series C Preferred Stock had been
    converted into shares of Common Stock as of the beginning of the respective
    periods.
 
(2) Adjusted for both periods to give effect to the issuance and sale of a
    sufficient number of shares of Common Stock in the Offering to redeem all
    the issued and outstanding shares of Series B Preferred Stock and pay the
    accrued dividends.
 
(3) Adjustments required to give effect for the exercise of the Series C
    Preferred Stock Warrants as described on page 5. See "--The Transactions."
 
(4) Adjustments to give effect to the conversion of all outstanding Series C
    Preferred Stock. See "--The Transactions."
 
(5) Adjustment to give effect to the $376,676 redemption premium on the Series B
    Preferred Stock.
 
(6) Adjusted to give effect to the Offering and the proposed application of net
    proceeds therefrom as described in "Use of Proceeds."
 
                       SUMMARY OPERATING AND RESERVE DATA
 
    The following table sets forth certain summary operating data for the
Company for the periods indicated:
 
<TABLE>
<CAPTION>
                                                                              NINE MONTH PERIODS
                                             YEAR ENDED DECEMBER 31,         ENDED SEPTEMBER 30,
                                        ----------------------------------  ----------------------
                                           1993        1994        1995        1995        1996
                                        ----------  ----------  ----------  ----------  ----------
<S>                                     <C>         <C>         <C>         <C>         <C>
PRODUCTION DATA (NET):
  Gas (MMcf)..........................      --           105.1        97.1        73.3       117.8
  Oil and condensate (MBbls)..........      --             6.1         6.7         4.5         6.5
  Total equivalent (MMcfe)............      --           141.7       137.3       100.3       156.8
 
AVERAGE SALES PRICE PER UNIT:
  Gas (Mcf)...........................      --      $      1.93 $      1.59 $      1.63 $      2.41
  Oil and condensate (Bbl)............      --            16.58       17.89       18.35       19.17
 
AVERAGE EXPENSES (PER MCFE):
  Lease operating (1).................      --      $      0.24 $      0.57 $      0.44 $      0.33
  Depletion of oil and gas properties
    (2)...............................      --             0.64        1.15        0.94        0.81
</TABLE>
 
- ------------------------
 
(1) Includes all direct expenses of operating the Company's properties, as well
    as severance and ad valorem taxes.
 
(2) Excludes depreciation and amortization of technical interpretation
    equipment, office furniture and equipment and office leasehold improvements,
    impairments of oil and gas properties and amortization of organization
    costs.
 
                                       7
<PAGE>
    The following table sets forth summary information with respect to the
Company's estimated proved oil and gas reserves as of each of the dates
indicated, which estimates have been prepared by the Company. Crude oil and
condensate are converted to Mcfe on the basis of one barrel of crude oil and
condensate to six Mcfe. See "Risk Factors--Uncertainty of Estimates of Oil and
Gas Reserves" and "Business--Oil and Gas Reserves."
 
<TABLE>
<CAPTION>
                                                  AT DECEMBER 31,
                                        -----------------------------------  AT SEPTEMBER 30,
                                          1993         1994         1995           1996
                                        ---------  ------------  ----------  ----------------
<S>                                     <C>        <C>           <C>         <C>
ESTIMATED NET PROVED RESERVES DATA:
  Gas (MMcf)..........................         20         1,237         443          2,169(1)
  Oil and condensate (MBbls)..........          4            40          41             31(1)
  Total equivalent (MMcfe)............         44         1,477         689          2,355
 
  Pre-tax present value of proved
    reserves discounted at 10%........  $  60,000  $  1,606,000  $  771,000  $   2,775,000(1)
</TABLE>
 
- ------------------------
 
(1) Estimates of the Company's net proved gas and oil and condensate reserves
    and related revenue estimates as of September 30, 1996 were prepared by the
    Company and 2,146 MMcf and 27.3 MBbls of such gas and oil and condensate
    volumes, respectively, and $2,723,338 of pre-tax present values, have been
    the subject of a reserve report (the "Ryder Scott Reserve Report") prepared
    by Ryder Scott Company ("Ryder Scott"). A summary report prepared by Ryder
    Scott is included as Appendix A hereto. The other oil and gas reserve
    volumes and values at September 30, 1996 relate to royalty interests in
    other wells which were engineered solely by the Company's personnel.
 
                                  RISK FACTORS
 
    See "Risk Factors" beginning on page nine for a discussion of certain
factors that should be considered by prospective purchasers of the shares of
Common Stock offered hereby.
 
           CAUTIONARY STATEMENT REGARDING FORWARD-LOOKING STATEMENTS
 
    Certain statements contained in this Prospectus under the captions
"Summary," "Risk Factors," "Management's Discussion and Analysis of Financial
Condition and Results of Operations" and "Business," including statements
regarding anticipated capital expenditures, estimates of proved reserves, future
rates of production and timing of capital expenditures and regulatory reform,
and other statements contained herein regarding matters that are not historical
facts, are forward-looking statements (as such term is defined in the Private
Securities Litigation Reform Act of 1995). Because such statements include risks
and uncertainties, actual results may differ materially from those expressed or
implied by such forward-looking statements. Factors that could cause actual
results to differ materially include, but are not limited to, those discussed
under "Risk Factors."
 
                                       8
<PAGE>
                                  RISK FACTORS
 
    IN ADDITION TO THE OTHER INFORMATION AND FINANCIAL DATA SET FORTH ELSEWHERE
IN THIS PROSPECTUS, THE FOLLOWING RISK FACTORS SHOULD BE CONSIDERED CAREFULLY IN
EVALUATING THE COMPANY AND ITS BUSINESS BEFORE PURCHASING THE SHARES OF COMMON
STOCK OFFERED HEREBY.
 
LIMITED OPERATING HISTORY AND SIGNIFICANT HISTORICAL OPERATING LOSSES
 
    The Company commenced its operations in 1993 and has only a limited
operating history. Potential investors, therefore, have limited historical
financial and operating information upon which to base an evaluation of the
Company's performance and an investment in shares of Common Stock. For example,
the producing wells within exploration projects in which the Company is
participating have been on production only for a short period of time.
Therefore, estimations with respect to the proved reserves and level of future
production attributable to these wells are difficult to determine and there can
be no assurance as to the volume of recoverable reserves that will be realized
from such wells. The Company's prospects must be considered in light of the
risks, expenses and difficulties frequently encountered by companies in the
early stages of their development. As a result of operating expenses, the
Company has incurred significant operating and net losses to date. Net losses
for 1993, 1994 and 1995 and the nine months ended September 30, 1996 were
approximately $615,000, $385,000, $2.5 million and $2.6 million, respectively.
At September 30, 1996, the Company had an accumulated deficit of $8.3 million.
The development of the Company's business and its participation in an
increasingly larger number of projects has required and will continue to require
substantial expenditures. The Company's future financial results will depend
primarily on its ability to economically locate hydrocarbons in commercial
quantities, to provide drilling site and target depth recommendations resulting
in profitable productive wells and on the market prices for oil and gas. There
can be no assurance that the Company will achieve or sustain profitability or
positive cash flows from operating activities in the future. See "--Substantial
Capital Requirements and Liquidity,"
"--Variability of Operating Results," "Selected Financial Data," "Management's
Discussion and Analysis of Financial Condition and Results of Operations" and
"Business--Oil and Gas Reserves."
 
VOLATILITY OF OIL AND GAS PRICES
 
    Although the Company's primary efforts are focused on reducing the
hydrocarbon finding costs in those projects in which it participates, the
Company's revenues, profitability, cash flow and future growth are affected by
changes in prevailing oil and gas prices. Oil and gas prices have been subject
to wide fluctuations in recent years in response to relatively minor changes in
the supply and demand for oil and gas, market uncertainty and a variety of
additional factors that are beyond the control of the Company, including
economic, political and regulatory developments and competition from other
sources of energy. It is impossible to predict future oil and gas price
movements with any certainty. Currently, the Company does not engage in hedging
activities. As a result, the Company may be more adversely affected by
fluctuations in oil and gas prices than other industry participants that do
engage in such activities. No assurances can be given as to the future level of
activity in the oil and gas exploration and development industry and its
relationship to the future demand for the expertise offered by the Company. An
extended or substantial decline in oil and gas prices could have a material
adverse effect on the Company's financial position and results of operations,
the volume of oil and gas that may be economically produced by operations of
projects in which the Company participates and the Company's access to capital.
See "Management's Discussion and Analysis of Financial Condition and Results of
Operations" and "Business--Oil and Gas Reserves."
 
RELIANCE ON SIGNIFICANT PARTNERS
 
    The Company has in the past and expects in the future to rely extensively
upon its existing and future partners to offer opportunities for the Company to
participate in exploration projects. As of the date of this Prospectus, all of
the Company's oil and gas revenues have been derived from its participation in
 
                                       9
<PAGE>
projects involving four partners. These four partners are Cox & Perkins
Exploration, Inc., Browning Oil Company, Prime Energy Management Corporation and
Parallel Petroleum Company. The Company's inability to secure future business
opportunities generated by these or other partners could limit the Company's
ability to fully implement its business plan and could have a material adverse
effect on the Company's business, financial condition and results of operations.
See "Business--Significant Business Relationships."
 
NON-OPERATOR STATUS
 
    The Company focuses exclusively on providing 3-D imaging and relies upon
other project partners to provide and complete all other project operations and
responsibilities including land acquisition, drilling, marketing and project
administration. As a result, the Company has only a limited ability to exercise
control over a significant number of a project's operations or the associated
costs of such operations. The success of a project is dependent upon a number of
factors which are outside of the Company's area of expertise and project
responsibilities. Such factors include: (i) the availability of favorable lease
terms and required permitting for projects, (ii) the availability of future
capital resources by the Company and the other participants for the purchasing
of leases and the drilling of wells, (iii) the approval of other participants to
the purchasing of leases and the drilling of wells on the projects and (iv) the
economic conditions at the time of drilling, including the prevailing and
anticipated prices for oil and gas. The Company's reliance on other project
partners and its limited ability to directly control certain project costs could
have a material adverse effect on the realization of expected rates of return on
the Company's investment in projects.
 
ABILITY TO DISCOVER ADDITIONAL RESERVES
 
    The Company's future success is dependent upon its ability to economically
locate additional oil and gas reserves in commercial quantities. The Company's
ability to do so is dependent upon a number of factors, including its
participation in multiple exploration projects and its technological capability
to locate oil and gas in commercial quantities. Because the Company does not
generate or develop its own projects (except in instances relating to trend
plays), relying instead upon other industry participants to do so, no assurances
can be given that the Company will have the opportunity to participate in
projects which economically produce commercial quantities of hydrocarbons in
amounts necessary to meet its business plan or that the projects in which it
elects to participate will be successful. Except to the extent that the Company
successfully locates commercial quantities of economically recoverable oil and
gas, the Company's proved reserves will decline as reserves are produced. There
can be no assurance that the Company will be able to discover additional
commercial quantities of oil and gas or that the Company's project partners will
have success drilling productive wells and acquiring properties at low finding
costs. See "--Non-Operator Status" and "Business--Oil and Gas Reserves."
 
SUBSTANTIAL CAPITAL REQUIREMENTS AND LIQUIDITY
 
    The Company makes, and will continue to make, substantial capital
expenditures for the development, exploration, acquisition and production of oil
and natural gas reserves. Historically, the Company has financed these
expenditures primarily with proceeds from the sale of its equity securities in
private offerings and cash generated by operations. The Company had oil and gas
capital expenditures of $2.2 million during 1995 and $2.9 million during the
nine months ended September 30, 1996, respectively, and as of November 1, 1996
planned to incur oil and gas capital expenditures of approximately $2.1 million
during the three months ended December 31, 1996 and approximately $14.9 million
in 1997. Management believes that the Company will have sufficient cash provided
by this Offering and by operating activities to fund planned capital
expenditures through 1997. However, if operating revenues are lower than the
Company anticipates, as a result of lower oil and gas prices, operating
difficulties or any other reason, the Company will not have the funds necessary
to undertake or complete its 1997 exploration program. There
 
                                       10
<PAGE>
can be no assurance that additional debt or equity financing will be available
to meet these requirements. See "Use of Proceeds" and "Management's Discussion
and Analysis of Financial Condition and Results of Operations--Liquidity and
Capital Resources."
 
UNCERTAINTY OF ESTIMATES OF OIL AND GAS RESERVES
 
    There are numerous uncertainties inherent in estimating oil and gas reserves
and in projecting future rates of production. Petroleum engineering is a
subjective process of estimating underground accumulations of oil and gas that
cannot be measured in an exact manner. Estimates of economically recoverable oil
and gas reserves and of future net cash flows depend upon a number of variable
factors and assumptions, such as historical production from the area compared
with production from other producing areas, the assumed effects of regulations
by governmental agencies, and assumptions concerning future oil and gas prices,
future operating cost, severance and excise taxes, development costs and
workover and remedial costs, all which may in fact vary considerably from actual
results. For these reasons, estimates of the economically recoverable quantities
of oil and gas attributable to any particular group of properties,
classifications of such reserves based on risk of recovery and estimates of the
future net cash flows expected therefrom prepared by different engineers or by
the same engineers at different times may vary substantially. Actual production,
revenues and expenditures with respect to the Company's reserves will likely
vary from estimates, and such variances may be material. See "Business--Oil and
Gas Reserves."
 
RISK OF EXPLORATORY DRILLING ACTIVITIES
 
    Pursuant to the Company's business plan, the Company's revenues and cash
flow will be principally dependent upon the success of the exploratory drilling
projects in which the Company participates. The success of such projects is
determined by the economical location, development and production of commercial
quantities of hydrocarbons. Exploratory drilling is subject to numerous risks,
including the risk that no commercially productive oil and gas reservoirs will
be encountered. The cost of drilling, completing and operating wells is often
uncertain and drilling operations may be curtailed, delayed or canceled as a
result of a variety of factors including unexpected formation and drilling
conditions, pressure or other irregularities in formations, equipment failures
or accidents, as well as weather conditions, compliance with governmental
requirements and shortages or delays in the delivery of equipment. In addition,
the Company's reliance upon 3-D imaging requires greater pre-drilling
expenditures than the alternative forms of more traditional drill site location
strategies, including 2-D imaging. For example, in one current project in which
the Company is participating, the Company estimates the pre-drilling
expenditures attributable to 3-D imaging in identifying an initial exploratory
drilling location were $2.25 million. The Company believes that the pre-drilling
expenditures which would have been incurred in identifying an initial
exploratory drilling location within such project utilizing 2-D imaging would
have been approximately $750,000. The inability to successfully locate and drill
wells that will economically produce commercial quantities of oil and gas would
have a material adverse effect on the Company's business, financial position and
results of operations. See "--Non-Operator Status" and "Management's Discussion
and Analysis of Financial Condition and Results of Operations--Overview."
 
BENEFITS OF THE OFFERING TO EXISTING STOCKHOLDERS
 
    Upon the consummation of the Offering, the Company intends to use
approximately $6.7 million or 28% of the net proceeds (24% of the net proceeds
if the Underwriters' over-allotment option is exercised in full) for the
immediate redemption of all issued and outstanding shares of Series B Preferred
Stock and approximately $780,000 or 3% of the net proceeds (3% of the net
proceeds if the Underwriters' over-allotment option is exercised in full) to pay
accrued but unpaid dividends on the issued and outstanding shares of Series C
Preferred Stock, prior to the conversion of such shares into Common Stock. See
"Prospectus Summary--The Transactions," "The Company," "Use of Proceeds" and
"Management's
 
                                       11
<PAGE>
Discussion and Analysis of Financial Condition and Results of
Operations--Liquidity and Capital Resources."
 
COMPETITION
 
    The exploration for and production of oil and gas are highly competitive.
Many companies and individuals are engaged in the business of acquiring
interests in and developing onshore and near onshore oil and gas properties in
the United States. The industry is not dominated by any single competitor or a
small number of competitors. The Company competes with a large number of
independent, technology-driven service companies and major and independent oil
and gas companies for the acquisition of desirable oil and gas properties, as
well as for the equipment and expertise required to operate and develop such
properties. Many of these competitors have financial and other resources
substantially in excess of those available to the Company. Such competitive
disadvantages could adversely affect the Company's ability to participate in
projects with favorable rates of return. See "Business--Competition."
 
TECHNOLOGICAL CHANGES
 
    The oil and gas industry is characterized by rapid and significant
technological advancements and introductions of new products and services
utilizing new technologies. As new technologies develop, the Company may be
placed at a competitive disadvantage, and competitive pressures may force the
Company to implement such new technologies at substantial cost. In addition,
other oil and gas finding companies may implement new technologies before the
Company, and consequently such companies may be able to provide enhanced
capabilities and superior quality compared with that which the Company is able
to provide. There can be no assurance that the Company will be able to respond
to such competitive pressures and implement such technologies on a timely basis
or at an acceptable cost. One or more of the technologies currently utilized by
the Company or implemented in the future may become obsolete. In such case, the
Company's business, financial condition and results of operations could be
materially adversely affected. If the Company is unable to utilize the most
advanced commercially available technology, the Company's business, financial
condition and results of operations could be materially and adversely affected.
See "Business--Competition."
 
OPERATING HAZARDS
 
    The exploration and development projects in which the Company participates
are subject to the usual hazards incident to the drilling of oil and gas wells,
such as cratering, explosions, uncontrollable flows of oil, gas or well fluids,
fires, pollution and other environmental risks. In addition, the offshore
projects are subject to the additional hazards of marine operations, such as
capsizing, collision and damage or loss from severe weather. These hazards can
cause personal injury and loss of life, severe damage to and destruction of
property and equipment, environmental damage and suspension of operations. The
Company indirectly, through operator partners, maintains insurance against some,
but not all, of the risks described above. See "Business--Operating Hazards and
Insurance."
 
COMPLIANCE WITH GOVERNMENTAL REGULATIONS
 
    Oil and gas operations are subject to extensive governmental regulation,
which may be changed from time to time in response to economic or political
conditions. The Company believes that the trend of more expansive and stricter
environmental laws and regulations will continue. The implementation of new, or
the modification of existing, environmental laws or regulations, including
regulations to be promulgated pursuant to the Oil Pollution Act of 1990, could
have a material adverse impact on the Company. See "Business--Regulation."
 
                                       12
<PAGE>
VARIABILITY OF OPERATING RESULTS
 
    The Company's operating results have in the past and may in the future
fluctuate significantly depending upon a number of factors including industry
conditions, prices of oil and gas, rate of drilling success, rates of production
from completed wells and the timing of capital expenditures. Such variability
could have a material adverse effect on the Company's business, financial
condition and results of operations. In addition, any failure or delay in the
realization of expected cash flows from operating activities could limit the
Company's ability to invest and participate in economically attractive projects.
See "--Limited Operating History and Significant Historical Operating Losses"
and "Management's Discussion and Analysis of Financial Condition and Results of
Operations."
 
RISKS ASSOCIATED WITH MANAGEMENT OF GROWTH AND IMPLEMENTATION OF GROWTH STRATEGY
 
    The Company's rapid growth has placed, and is expected to continue to place,
a significant strain on the Company's financial, technical, operational and
administrative resources. As the Company increases its services and enlarges the
number of projects it is evaluating or in which it is participating, there will
be additional demands on the Company's financial, technical and administrative
resources. The failure to continue to upgrade the Company's technical,
administrative, operating and financial control systems or the occurrence of
unexpected expansion difficulties, including the recruitment and retention of
geoscientists and engineers, could have a material adverse effect on the
Company's business, financial condition and results of operations. See
"Business--Prospect Generation."
 
DEPENDENCE ON KEY PERSONNEL
 
    The Company has assembled a team of geologists, geophysicists and engineers
who have considerable experience effectively applying 3-D imaging technologies.
The Company is dependent upon the knowledge, skills and experience of these
experts to provide 3-D imaging and assist the Company in reducing the risks
associated with its participation in oil and gas exploration projects. In
addition, the success of the Company's business also depends to a significant
extent upon the abilities and continued efforts of its management, particularly
C. Eugene Ennis, the Company's President and Chief Executive Officer, Peter M.
Duncan, Vice President of Technology and Douglas C. Nester, Vice President of
Exploration. The Company maintains key man insurance on the lives of each of
Messrs. Ennis and Nester and Dr. Duncan in the amounts of $1.5 million, $500,000
and $500,000, respectively. The Company does not have employment agreements with
any of its employees. The loss of the services of key management personnel or
the Company's technical experts, or the inability to attract additional
qualified personnel, could have a material adverse effect on the Company's
business, financial condition, results of operations, development efforts and
ability to expand. There can be no assurance that the Company will be successful
in attracting and retaining such executives, geoscientists and engineers. See
"Management--Directors and Executive Officers" and "Management--Geoscientists
and Engineers."
 
BROAD DISCRETION OVER USE OF PROCEEDS
 
    Approximately $14.9 million, or 63%, of the estimated net proceeds of the
Offering has been allocated for capital expenditures to implement the Company's
exploration and development program. Due to the number and variability of the
factors that will be analyzed before the Company specifically identifies and
commits to participate in projects or otherwise apply such net proceeds, the
Company will have broad discretion to allocate a significant portion of the net
proceeds from the Offering without any action or approval of the Company's
stockholders. Accordingly, investors in the Common Stock will not have the
opportunity to evaluate the economic, financial and other relevant information
that will be considered by the Company in determining the application of such
net proceeds. See "Use of Proceeds."
 
                                       13
<PAGE>
ABSENCE OF PRIOR PUBLIC MARKET; POSSIBLE VOLATILITY OF STOCK PRICE
 
    Prior to the Offering there has been no public market for the Common Stock,
and although the Company has listed the Common Stock on the Nasdaq National
Market System there can be no assurance that following the Offering an active
trading market will develop or be maintained. The initial public offering price
of the Common Stock offered hereby has been determined by negotiation between
the Company and the representatives of the Underwriters and may bear no
relationship to the price at which the Common Stock will trade after completion
of the Offering. For factors considered in determining the initial public
offering price, see "Underwriting." After completion of the Offering, the market
price of the Common Stock could be subject to significant fluctuations in
response to various factors and events, including the liquidity of the market
for the Common Stock, variations in the Company's quarterly operating results,
regulatory or other changes in the oil and gas industry generally, announcements
of business developments by the Company or its competitors, changes in operating
costs and changes in general market conditions. See "--Variability of Operating
Results."
 
IMMEDIATE AND SUBSTANTIAL DILUTION
 
    Based upon the initial public offering price of $11.00 per share of Common
Stock, purchasers of Common Stock in the Offering will experience immediate and
substantial dilution of $7.32 per share in net tangible book value of
outstanding Common Stock. See "Dilution."
 
SHARES ELIGIBLE FOR FUTURE SALE
 
    Future sales of Common Stock by existing stockholders under Rule 144 ("Rule
144") of the Securities Act of 1933, as amended (the "Securities Act"), through
the exercise of outstanding registration rights or otherwise, could have an
adverse effect on the market price of the Common Stock and the ability of the
Company to raise capital in the future. The shares of Common Stock sold in the
Offering will be eligible for immediate resale, except to the extent acquired by
affiliates of the Company. Commencing 180 days after the effective date of the
Registration Statement of which this Prospectus is a part (the "Effective
Date"), approximately 2,887,908 additional shares of Common Stock will be
eligible for sale in the public market pursuant to Rule 144 upon expiration of
lock-up agreements with the Underwriters. The remaining 1,517,140 shares
outstanding upon completion of the Offering will be eligible for sale pursuant
to Rule 144 upon the expiration of the current two-year holding period. Certain
existing stockholders have rights under certain circumstances to require the
Company to register a total of 4,401,925 shares of Common Stock commencing 180
days after the effective date of the Registration Statement of which this
Prospectus forms a part. See "Description of Capital Stock--Registration
Rights," "Shares Eligible for Future Sale" and "Underwriting."
 
    The Securities and Exchange Commission (the "Commission") has proposed
amendments to Rule 144 which would reduce the holding period required for shares
subject to Rule 144 to become eligible for resale on the public market. This
proposal, if adopted, would increase the number of shares of the Company's
Common Stock eligible for immediate resale following the expiration of lock-up
agreements.
 
ANTI-TAKEOVER CONSIDERATIONS
 
    Prior to completion of the Offering, the Company's Restated Certificate of
Incorporation, filed with the office of the Secretary of State of the State of
Delaware on July 26, 1995 (the "Certificate of Incorporation") and Amended and
Restated By-laws (the "Bylaws") was amended and restated to include certain
provisions that are intended to enhance the likelihood of continuity and
stability in the composition of the Company's Board of Directors. These
provisions may have the effect of delaying, deterring or preventing a future
takeover or change in control of the Company unless such takeover or change in
control is approved by the Company's Board of Directors, even though such a
transaction may offer the holders of Common Stock the opportunity to sell their
stock at a price above the prevailing market price.
 
                                       14
<PAGE>
Such provisions may also render the removal of directors and management more
difficult. Specifically, the Certificate of Incorporation and Bylaws, as the
case may be, have been amended to provide for a classified Board of Directors
serving staggered, three-year terms and certain advance notice requirements for
stockholder nominations of candidates for election to the Company's Board of
Directors and certain other stockholder proposals. Such provisions could limit
the price that certain persons might be willing to pay in the future for shares
of Common Stock. In addition, prior to completion of the Offering, the
Certificate of Incorporation was amended and restated to authorize the Board of
Directors of the Company to issue from time to time, without any further action
of stockholders, up to one million shares of Preferred Stock (as defined
herein), on such terms and with such rights, designations, preferences,
qualifications, limitations and restrictions as the Board of Directors may
determine. The issuance of such Preferred Stock, depending upon the rights,
designations, preferences, qualifications, limitations and restrictions thereof,
may have the effect of delaying, deterring or preventing a change in control of
the Company or may otherwise adversely affect the interests of holders of Common
Stock. Further, certain provisions of the Delaware General Corporation Law (the
"DGCL") prevent certain stockholders from engaging in business combinations with
the Company, subject to certain exceptions. See "Description of Capital Stock--
Preferred Stock," "Description of Capital Stock--Certain Provisions of the
Certificate of Incorporation and Bylaws" and "Description of Capital
Stock--Delaware Anti-Takeover Law."
 
                                       15
<PAGE>
                                  THE COMPANY
 
    3DX Technologies is a knowledge-based oil and gas exploration company whose
core competence and strategic focus is the utilization of 3-D seismic imaging
and other advanced technologies in the search for commercial quantities of
hydrocarbons. The Company was founded by C. Eugene Ennis, Peter M. Duncan and
Douglas C. Nester and began operations in January 1993 to take advantage of
perceived opportunities emerging from changes in the domestic oil and gas
industry, including the divestiture of domestic oil and gas properties, advances
in technology and the outsourcing of specialized technical capabilities. Since
it commenced operations, the Company has acquired working interests (generally
ranging from 5% to 20%, although the Company has increased its working interest
in certain selected exploration trends) in 30 projects and has found 40.3 Bcfe
(2.8 Bcfe net to the Company's interest), of which 27.0 Bcfe (2.1 Bcfe net to
the Company's interest) was found during the first nine months of 1996. As of
the date of this Prospectus, the Company has working interests in 24 projects.
 
    During its initial phase of operations in 1993 and 1994, the Company pursued
projects in West Texas and other domestic onshore areas. Although drilling
results from these projects were favorable, the Company generally held small
interests in such projects and ultimately determined that the Gulf Coast would
provide the Company with a greater opportunity for the development of its
business plan. Since that time, the Company has focused its efforts principally
in the Gulf Coast region although it has and will continue to pursue
opportunities that may become available in other select geographic areas. As a
result of its initial experiences, the Company has developed a unique method of
evaluating business opportunities, assembled a team of experienced
explorationists and created innovative exploration techniques based on advanced
technology to enable it to identify and participate in economically attractive
projects. The Company believes that its technological expertise together with
increased capital resources will enable the Company to further implement its
business plan and growth strategy and achieve its operational and financial
goals.
 
    The Company was initially capitalized in January 1993 through (i) the
issuance and sale of 768,117 shares of Common Stock to the Company's three
founders and (ii) the issuance of 100,000 shares of Convertible Preferred Stock,
Series A, par value $0.01 per share ("Series A Preferred Stock"), to Landmark
Graphics Corporation ("Landmark Graphics") for total consideration valued by the
parties at $500,000. The issued and outstanding shares of Series A Preferred
Stock were subsequently exchanged by Landmark Graphics for 329,003 shares of
Common Stock. Thereafter, in November 1993 and October 1994 the Company raised
additional capital in the amount of $5.4 million through the sale of units
("Units"), each Unit consisting of one share of Series B Preferred Stock and
30.215 shares of Common Stock. Additional capital in the amount of $8.0 million
was raised by the Company in a private placement of Series C Preferred Stock
during the third quarter of 1995. See "Management's Discussion and Analysis of
Financial Condition and Results of Operations--Liquidity and Capital Resources."
The Company's largest stockholders include Citi Growth Fund L.P., R. Chaney &
Partners-1993 L.P., Centennial Associates, L.P. and each of the founders, all of
which have invested in both the Units and the Series C Preferred Stock, and
NationsBanc Capital Corporation, Metropolitan Life Insurance Company and
Centennial Energy Partners, L.P., all of which have invested exclusively in
Series C Preferred Stock. See "Principal Stockholders and Selling Stockholders."
 
    The Company's principal executive offices are located at 12012 Wickchester,
Suite 250, Houston, Texas. Its telephone number is (713) 579-3398.
 
                                       16
<PAGE>
                                USE OF PROCEEDS
 
    The net proceeds to be received by the Company from the sale of the shares
of Common Stock offered hereby, after deducting estimated underwriting discounts
and commissions and estimated expenses of the Offering, are estimated to be
approximately $23.8 million ($27.6 million if the Underwriters' over-allotment
option is exercised in full).
 
    Of the net proceeds of the Offering to be received by the Company, the
Company intends to use (i) approximately $14.9 million to fund the Company's
exploration and development program, (ii) approximately $7.5 million to redeem
all of the issued and outstanding shares of Series B Preferred Stock and to pay
accrued but unpaid dividends on the Series C Preferred Stock and (iii) the
remainder for general corporate purposes, including expenses associated with
hiring additional personnel. Specifically, during 1997, the Company intends to
apply the net proceeds of the Offering in connection with budgeted oil and gas
exploration and development expenditures which relate to estimated costs
expected to be incurred as follows: (i) $8.6 million in projects within the
Texas Gulf Coast trend; (ii) $2.5 million in projects within the
Mississippi/Alabama trend; (iii) $870,000 in projects within the Sunniland
trend; and (iv) $2.9 million in projects located in South Louisiana. The
budgeted expenditures relate to costs incurred in connection with the
acquisition of land and seismic data, the interpretation of seismic data and the
drilling of exploratory and development wells. No assurances can be given
however that actual expenditures will not vary significantly from such budgeted
amounts.
 
    Because of the number and variability of factors that determine the
Company's use of the net proceeds of the Offering, management will retain a
significant amount of discretion over their application. There can be no
assurance that such application will not vary substantially from the Company's
plans described above. In addition, there can be no assurance that the Company
will be able to generate or raise sufficient capital to enable it to realize
fully all of its strategic objectives. See "Risk Factors--Substantial Capital
Requirements and Liquidity" and "Risk Factors--Broad Discretion Over Use of
Proceeds."
 
    Pending application of the net proceeds of the Offering, the Company expects
that it will invest such funds in interest-bearing accounts or in United States
government securities or other short term interest bearing investment grade
securities.
 
                                DIVIDEND POLICY
 
    The Company has not declared or paid any cash dividends on its Common Stock
since its formation and does not presently anticipate paying any cash dividends
on its Common Stock in the foreseeable future. The Company currently intends to
retain any future earnings to finance the expansion and continued development of
its business. The future payment of cash dividends on the Common Stock will be
within the sole discretion of the Company's Board of Directors and will depend
upon the earnings, capital requirements and financial position of the Company,
applicable requirements of the DGCL, general economic conditions and other
factors considered relevant by the Company's Board of Directors.
 
                                       17
<PAGE>
                                    DILUTION
 
    The Company's pro forma net tangible book value as of September 30, 1996 was
approximately $1.6 million or $0.36 per share. Pro forma net tangible book value
per share represents the total amount of tangible assets of the Company, less
the total amount of liabilities of the Company, divided by the number of shares
of Common Stock outstanding on a fully diluted basis. All of the amounts below
give effect to the Transactions. After giving effect to the sale by the Company
of the 2,400,000 shares of Common Stock pursuant to the Offering at the initial
public offering price of $11.00 per share, less estimated underwriting discounts
and commissions and estimated expenses of the Offering payable by the Company,
and the application of the estimated net proceeds therefrom, the Company's pro
forma net tangible book value as of September 30, 1996 would have been
approximately $25.4 million, or $3.68 per share of Common Stock. This represents
an immediate increase in net tangible book value of $3.32 per share to existing
stockholders and an immediate dilution in net tangible book value of $7.32 per
share to new investors purchasing shares of Common Stock in the Offering (based
upon the initial public offering price of $11 per share). The following tables
provide the computation of pro forma net tangible book value and illustrate this
dilution on a per share basis to the new investors:
 
<TABLE>
<CAPTION>
                                                                                                      AMOUNT
                                                                                            --------------------------
                                                                            COMMON SHARES       TOTAL       PER SHARE
                                                                           ---------------  -------------  -----------
<S>                                                                        <C>              <C>            <C>
Actual net tangible book value at September 30, 1996.....................      2,991,032    $  (6,706,920)  $   (2.24)
Conversion of all issued and outstanding shares of Series C Preferred
  Stock..................................................................      1,376,379        7,912,368
Exercise and conversion of Series C Preferred Stock Warrants.............        137,638          798,672
Premium incurred on redemption of all issued and outstanding shares of
  Series B Preferred Stock...............................................                        (376,676)
                                                                           ---------------  -------------
Pro forma net tangible book value at September 30, 1996..................      4,505,049        1,627,444   $    0.36
Net Offering proceeds....................................................      2,400,000       23,777,000
                                                                           ---------------  -------------
Pro forma net tangible book value at September 30, 1996 after the
  Offering...............................................................      6,905,049    $  25,404,444   $    3.68
 
Initial public offering price per share of Common Stock..................                   $       11.00
  Pro forma net tangible book value per share of Common Stock at
    September 30, 1996...................................................    $      0.36
  Increase in net tangible book value per share attributable to net
    proceeds of the Offering.............................................           3.32
                                                                           ---------------
Pro forma net tangible book value per share after giving effect to the
  Offering...............................................................                            3.68
                                                                                            -------------
Immediate dilution in net tangible book value per share of Common Stock
  to new investors.......................................................                   $        7.32
                                                                                            -------------
                                                                                            -------------
</TABLE>
 
    The following table sets forth, on a pro forma basis as of September 30,
1996, the number of shares of Common Stock purchased from the Company, the total
consideration paid to the Company and the average price per share paid by
existing stockholders and by new investors in this Offering at the initial
public offering price of $11.00 per share before deducting the estimated
underwriting discounts and commissions and estimated expenses of the Offering
payable by the Company:
 
<TABLE>
<CAPTION>
                                                     SHARES PURCHASED       TOTAL CONSIDERATION       AVERAGE
                                                   ---------------------  ------------------------   PRICE PER
                                                     NUMBER     PERCENT      AMOUNT       PERCENT      SHARE
                                                   ----------  ---------  -------------  ---------  -----------
<S>                                                <C>         <C>        <C>            <C>        <C>
Existing stockholders............................   4,505,049       65.2% $   9,696,294       26.9%  $    2.15
New investors....................................   2,400,000       34.8%    26,400,000       73.1%      11.00
                                                   ----------  ---------  -------------  ---------
    Total........................................   6,905,049      100.0% $  36,096,294      100.0%       5.23
                                                   ----------  ---------  -------------  ---------
                                                   ----------  ---------  -------------  ---------
</TABLE>
 
    The above tables exclude options to purchase 794,479 shares of Common Stock
at exercise prices ranging from $0.19 to $11.20, which have been granted under
the Stock Option Plan and are outstanding as of the date hereof and assume no
exercise of the Underwriters' over-allotment option. See "Management--Stock
Option Plan."
 
                                       18
<PAGE>
                                 CAPITALIZATION
 
    The following table sets forth each of the historical capitalization of the
Company as of September 30, 1996 and the pro forma and as adjusted
capitalization of the Company after giving effect to the Transactions and the
issuance and sale of the shares of Common Stock by the Company pursuant to the
Offering at the initial public offering price of $11.00 per share and the
application of the estimated net proceeds from the Offering as described in "Use
of Proceeds." This table should be read in conjunction with the Financial
Statements of the Company, the notes thereto and the other financial data
included elsewhere in this Prospectus.
 
<TABLE>
<CAPTION>
                                                                      AS OF SEPTEMBER 30, 1996
                                                    -------------------------------------------------------------
                                                                     PRO FORMA                    AS ADJUSTED FOR
                                                     HISTORICAL    ADJUSTMENTS(3)    PRO FORMA      OFFERING(4)
                                                    -------------  --------------  -------------  ---------------
<S>                                                 <C>            <C>             <C>            <C>
Cash and cash equivalents.........................  $   3,762,208   $    798,672   $   4,560,880   $  20,870,357
                                                    -------------  --------------  -------------  ---------------
                                                    -------------  --------------  -------------  ---------------
Long-term debt....................................  $    --         $    --        $    --         $    --
                                                    -------------  --------------  -------------  ---------------
                                                    -------------  --------------  -------------  ---------------
Mandatorily Redeemable Preferred Stock, Series B,
 $0.01 par value; 200,000 shares authorized,
 66,871 issued and outstanding, historical; no
 shares issued and outstanding, as adjusted.......      6,310,424        376,676       6,687,100        --
Senior Mandatorily Redeemable Convertible
 Preferred Stock, Series C, $0.01 par value;
 3,300,000 shares authorized, 2,662,241 issued and
 outstanding, historical; no shares issued and
 outstanding, as adjusted.........................      7,912,368     (7,912,368)       --              --
Common Stockholders' deficit:
Common Stock, $0.01 par value; 12,000,000 shares
 authorized, 2,991,032 shares issued and
 outstanding, historical; 20,000,000 shares
 authorized, 7,005,049 shares issued and
 outstanding, as adjusted(1)......................         29,910         15,140          45,050          69,050
Paid-in capital (net)(2)..........................      3,045,889      8,695,900      11,741,789      35,494,789
Deferred compensation related to certain stock
 options..........................................     (1,529,773)       --           (1,529,773)     (1,529,773)
Accumulated deficit...............................     (8,250,541)      (376,676)     (8,627,217)     (8,627,217)
                                                    -------------  --------------  -------------  ---------------
Common stockholders' (deficit) equity.............     (6,704,515)     8,334,364       1,629,849      25,406,849
                                                    -------------  --------------  -------------  ---------------
  Total capitalization............................  $   7,518,277   $    798,672   $   8,316,949   $  25,406,849
                                                    -------------  --------------  -------------  ---------------
                                                    -------------  --------------  -------------  ---------------
</TABLE>
 
- ------------------------
 
(1) Excludes 1,501,813 shares of Common Stock reserved for issuance upon the
    exercise of stock options which may be granted under the Stock Option Plan,
    of which options to purchase 794,479 shares of Common Stock have been
    granted and are outstanding as of the date hereof.  See "Management--Stock
    Option Plan." Upon consummation of the Offering, the Company's authorized
    capital will consist of a total of 21,000,000 shares of capital stock, which
    will be comprised of 20,000,000 shares of Common Stock and 1,000,000 shares
    of Preferred Stock, par value $0.01 per share (the "Preferred Stock").
 
(2) Net of notes receivable from the sale of shares of Common Stock in the
    amount of $16,448.
 
(3) Adjustments required to give effect for the exercise of the Series C
    Preferred Stock Warrants, the conversion of the Series C Preferred Stock
    into Common Stock and the charge to accumulated deficit of the $376,676
    redemption premium for the Series B Preferred Stock as described on page 5.
    See "Prospectus Summary--The Transactions."
 
(4) Adjusted to give effect to the Offering and the application of net proceeds
    therefrom to redeem the issued and outstanding shares of Series B Preferred
    Stock and pay accrued but unpaid dividends on the issued and outstanding
    shares of Series C Preferred Stock as described in "Use of Proceeds."
 
                                       19
<PAGE>
                            SELECTED FINANCIAL DATA
 
    The financial information set forth below as of December 31, 1993 and for
the period from inception of operations (January 6, 1993) through December 31,
1993 and as of and for the years ended December 31, 1994 and 1995 is derived
from the Financial Statements of the Company, which were audited by Arthur
Andersen LLP. The financial information set forth below as of September 30, 1996
and for the nine month periods ended September 30, 1995 and 1996 is derived from
unaudited financial statements of the Company which, in the opinion of
management, include all adjustments necessary for a fair presentation of the
financial condition and results of operations of the Company for such periods.
The results of operations for interim periods are not necessarily indicative of
a full year's operations. This information should be read in conjunction with
"Management's Discussion and Analysis of Financial Condition and Results of
Operations," the Financial Statements of the Company, the notes related thereto
and the other financial data included elsewhere in this Prospectus.
 
<TABLE>
<CAPTION>
                                                PERIOD FROM
                                               INCEPTION OF
                                                OPERATIONS             YEAR ENDED              NINE MONTH PERIODS
                                             (JANUARY 6, 1993)        DECEMBER 31,            ENDED SEPTEMBER 30,
                                                  THROUGH       -------------------------  --------------------------
                                             DECEMBER 31, 1993     1994          1995          1995          1996
                                             -----------------  -----------  ------------  ------------  ------------
                                                                                                  (UNAUDITED)
<S>                                          <C>                <C>          <C>           <C>           <C>
STATEMENT OF OPERATIONS DATA:
Revenues:
  Oil and gas..............................    $    --          $   303,836  $    274,511  $    202,185  $    408,459
  Rental income............................          127,034        100,962        58,195        45,563       120,098
  Interest and other.......................            7,528         52,817       236,186       125,549       217,678
                                             -----------------  -----------  ------------  ------------  ------------
    Total revenues.........................          134,562        457,615       568,892       373,297       746,235
 
Costs and expenses:
  Lease operating..........................         --               14,225        60,877        31,443        28,463
  Production taxes.........................         --               19,812        17,656        12,380        22,764
  Impairment of oil and gas properties.....         --              --          1,627,321     1,477,567     1,476,690
  Depletion, depreciation & amortization...           65,368        210,347       446,350       287,933       463,573
  General and administrative...............          596,267        598,244       905,063       652,671     1,343,660
  Interest and other.......................           88,006        --            --            --                289
                                             -----------------  -----------  ------------  ------------  ------------
    Total costs and expenses...............          749,641        842,628     3,057,267     2,461,994     3,335,439
                                             -----------------  -----------  ------------  ------------  ------------
 
Net loss from continuing operations........         (615,079)      (385,013)   (2,488,375)   (2,088,697)   (2,589,204)
Dividends on preferred stock...............          (52,790)      (421,696)   (1,058,956)     (113,257)     (505,167)
Accretion on preferred stock...............          (14,353)       (30,367)      (48,408)      (34,681)      (41,133)
                                             -----------------  -----------  ------------  ------------  ------------
Net loss from continuing operations
 applicable to common stockholders.........    $    (682,222)   $  (837,076) $ (3,595,739) $ (2,236,635) $ (3,135,504)
                                             -----------------  -----------  ------------  ------------  ------------
                                             -----------------  -----------  ------------  ------------  ------------
Pro forma net loss from continuing
 operations applicable to common
 stockholders (unaudited) (1)..............                                  $ (2,488,375)               $ (2,589,204)
                                                                             ------------                ------------
                                                                             ------------                ------------
 
Pro forma primary and fully diluted net
 loss from continuing operations per share
 (unaudited)...............................                                  $      (0.47)               $      (0.49)
                                                                             ------------                ------------
                                                                             ------------                ------------
 
Pro forma weighted average number of common
 shares outstanding (unaudited) (2)........                                     5,335,982                   5,337,553
                                                                             ------------                ------------
                                                                             ------------                ------------
</TABLE>
 
                                       20
<PAGE>
 
<TABLE>
<CAPTION>
                                                                                   SEPTEMBER 30, 1996
                                                                --------------------------------------------------------
                                        DECEMBER 31,                                  (UNAUDITED)
                              --------------------------------                PRO FORMA                  AS ADJUSTED FOR
                                1993       1994        1995       ACTUAL     ADJUSTMENTS     PRO FORMA     OFFERING(6)
                              ---------  ---------  ----------  ----------  --------------  -----------  ---------------
<S>                           <C>        <C>        <C>         <C>         <C>             <C>          <C>
BALANCE SHEET DATA:
  Working capital...........  $2,003,266 $2,102,586 $7,264,763  $3,435,650   $    798,672(3)  $4,234,322   $20,543,799
  Property and equipment,
    net.....................    635,696  2,669,177   2,935,093   4,852,759        --         4,852,759       4,852,759
  Total assets..............  2,791,694  5,196,795  10,450,504   8,994,140        798,672(3)  9,792,812     26,102,289
  Accrued dividends.........     --         --         275,256     780,423        --           780,423         --
  Long-term debt............     --         --          --          --            --            --             --
  Series B Preferred
    Stock...................  2,630,825  5,451,522   6,277,826   6,310,424        376,676(5)  6,687,100        --
  Series C Preferred
    Stock...................     --         --       7,903,833   7,912,368     (7,912,368)(4)     --           --
  Common Stockholders'
    equity (deficit)........  $  16,365  $(673,972) $(4,240,319) $(6,704,515)  $  8,334,364(     (5)  $1,629,849   $25,406,849
</TABLE>
 
- ------------------------------
 
(1) Adjusted to eliminate dividends and accretion on the issued and outstanding
    shares of Series B Preferred Stock and Series C Preferred Stock as if the
    shares of Series B Preferred Stock had been redeemed and the shares of
    Series C Preferred Stock had been converted into shares of Common Stock as
    of the beginning of the respective periods.
 
(2) Adjusted for both periods to give effect to the issuance and sale of a
    sufficient number of shares of Common Stock in the Offering to redeem all
    the issued and outstanding shares of Series B Preferred Stock and pay the
    accrued dividends.
 
(3) Adjustments required to give effect for the exercise of the Series C
    Preferred Stock Warrants as described on page 5. See "Prospectus
    Summary--The Transactions."
 
(4) Adjustments required to give effect to the conversion of all outstanding
    Series C Preferred Stock as described on page 5. See "-- The Transactions."
 
(5) Adjustment required to give effect to the $376,676 redemption premium on the
    Series B Preferred Stock.
 
(6) Adjusted to give effect to the Offering and the proposed application of net
    proceeds therefrom as described in "Use of Proceeds."
 
                                       21
<PAGE>
                      MANAGEMENT'S DISCUSSION AND ANALYSIS
                OF FINANCIAL CONDITION AND RESULTS OF OPERATIONS
 
    The following is a discussion of the financial condition and results of
operations of the Company for the nine months ended September 30, 1995 and 1996
and the three years ended December 31, 1993, 1994 and 1995. This discussion
should be read in conjunction with the Financial Statements of the Company, the
notes related thereto and the other financial data included elsewhere in this
Prospectus.
 
OVERVIEW
 
    3DX Technologies is a knowledge-based oil and gas exploration company whose
core competence and strategic focus is the utilization of 3-D imaging and other
advanced technologies in the search for commercial quantities of hydrocarbons.
The Company only enters into arrangements that enable it to combine its
expertise and exploration capabilities with the operating skills of other oil
and gas companies. The Company participates in carefully selected exploration
projects as a non-operating, working interest owner, sharing both risks and
rewards with its partners. The Company commenced operations in January 1993 to
take advantage of perceived opportunities emerging from changes in the domestic
oil and gas industry, including the divestiture of domestic oil and gas
properties, advances in technology and the outsourcing of specialized technical
capabilities. By reducing drilling risk through 3-D imaging and analysis, the
Company seeks to improve the expected return on investment in its oil and gas
projects.
 
    The working interest acquired by the Company in any project is determined
through negotiations among the Company and its prospective partners prior to the
Company's commitment to participate. The percentage working interest which the
Company seeks to acquire varies with each project and is dependent upon the
project's anticipated costs, risk and potential return. During the course of the
project, the Company's working interest is subject to change as a result of
negotiated cost and working interest sharing arrangements, the terms of which
are known to the Company prior to its commitment to participate.
 
    Expenditures made in oil and gas exploration vary with each project
depending principally on the costs related to the acquisition of land and
seismic data, analysis of seismic data and the expenses incurred in drilling
exploratory and development wells. In addition, costs attributable to the
acquisition of 3-D seismic data are initially greater than those which would be
incurred if 2-D seismic data were acquired. The Company, however believes that
the benefits derived from the use of 3-D imaging greatly outweigh the
incremental costs which are incurred through the utilization of 3-D imaging
rather than 2-D imaging. Specifically, by utilizing 3-D imaging technology, the
Company is able to acquire greater volumes and enhanced quality of subsurface
information not attainable with 2-D seismic data. Through the use of 3-D imaging
technologies, the Company is able to acquire in one instance seismic data
covering a prospective well target which may have been previously identified and
any other prospective well targets in the surrounding geographic area. As a
result of the Company's utilization of the higher quality and significantly
larger quantity of information obtainable only from 3-D imaging technology, the
Company has enhanced its ability to identify drill site locations which are
expected to maximize production from any particular well, may enhance the
Company's overall project return through the identification of multiple
prospective wells, and enable the Company to avoid unnecessary drilling
expenditures which it might otherwise incur had it relied only upon 2-D seismic.
 
    As a working interest partner, the Company shares all project costs in
proportion to its working interest percentage. In instances in which exploration
and development activities are unsuccessful, the Company incurs a loss equal to
its proportionate share of project costs prior to the time the project is
abandoned. Similarly, the Company will incur a loss if the Company's
proportionate share of revenue generated from production is insufficient to
cover the Company's share of project costs.
 
    During 1993, the Company commenced its business operations and initiated
participation as a working interest partner in two projects, the Bright Falcon
project and the Fausse Pointe project. See "Business--Significant Projects and
Properties." The Company did not have oil and gas revenues during 1993. To
finance its operations and acquire funds for capital expenditures, the Company
sold equity securities through private placement offerings raising approximately
$3.5 million. See "The Company."
 
                                       22
<PAGE>
    During 1994, the Company acquired working interests in seven projects and
successfully drilled and completed seven gross wells. The Company's oil and gas
revenues in 1994 totaled $304,000. To supplement operating revenues and enable
it to continue to implement its exploration program, the Company raised
additional capital in the approximate amount of $2.5 million through a private
placement of its equity securities in October 1994. See "The Company."
 
    During 1995, the Company continued to expand its operating activities by
acquiring working interests in six additional projects and successfully drilling
and completing two gross wells. The Company recognized total oil and gas
revenues in the amount of $275,000 during 1995. Through a private placement, the
Company raised additional capital in the approximate amount of $8.0 million to
finance continued capital expenditures in connection with the further
implementation of its exploration and development program.
 
    During the nine months ended September 30, 1996, the Company recognized oil
and gas revenues totaling $408,000 and owned working interests in 21 projects,
11 of which were acquired during this period. During the nine months ended
September 30, 1996, the Company drilled and completed eight gross successful
wells. See "--Working Interests Acquired Subsequent to September 30, 1996." The
Company intends to use approximately $14.9 million of net proceeds from this
Offering for capital expenditures to increase the number of projects in which it
is participating and to enable the Company to acquire working interests larger
than the working interest percentages the Company has had the available capital
to acquire in the past. See "Use of Proceeds."
 
    Since it commenced operations in January 1993, the Company has acquired
working interests in 30 projects of which it has discontinued its participation
in six projects. As of the date of this Prospectus, the Company is currently
participating in 24 projects. The Company elected to discontinue its
participation in the six projects after determining that such projects were
unlikely to produce commercial quantities of hydrocarbons. Such determinations
were made after drilling an unsuccessful well in each of three projects and
after reviewing "seismic data" prior to drilling in each of the other three
projects. Subsequent to September 30, 1996, the Company has acquired working
interests in four additional projects and discontinued its participation in one
project in which it had a working interest as of September 30, 1996. See
"--Working Interests Acquired Subsequent to September 30, 1996."
 
    The Company currently anticipates that it will participate in the drilling
of between 35 and 40 gross wells during 1997, although the number of wells may
increase as additional projects are added to the Company's portfolio. However,
there can be no assurance that such wells will be drilled and if drilled that
such wells will be successful. See "Risk Factors--Risks of Exploratory Drilling
Activities."
 
    The Company's future financial results will depend primarily on: (i) the
Company's ability to continue to source and screen potential projects; (ii) the
Company's ability to discover commercial quantities of hydrocarbons; (iii) the
market price for oil and gas; and (iv) the Company's ability to fully implement
its exploration and development program. There can be no assurance that the
Company will be successful in any of these respects or that the prices of oil
and gas prevailing at the time of production will be at a level allowing for
profitable production. See "Risk Factors--Limited Operating History and
Significant Historical Operating Losses," "Risk Factors--Volatility of Oil and
Gas Prices," "Risk Factors--Ability to Discover Additional Reserves," "Risk
Factors--Substantial Capital Requirements and Liquidity" and "Risk
Factors--Risks of Exploratory Drilling Activities."
 
    In connection with the implementation of its exploration and development
program, the Company intends to use a portion of the net proceeds of the
Offering to expand its technical and support staff. As a result, the Company
anticipates that its general and administrative expenses will increase in 1997.
Further, the Company anticipates incurring additional legal, administrative and
accounting costs in future periods as a result of the Company becoming a
publicly-held company.
 
    The Company uses the full-cost method of accounting for its oil and gas
properties. Under this method, all acquisition, exploration and development
costs, including certain general and administrative costs that are directly
attributable to the Company's acquisition, exploration and development
activities, are capitalized in a "full-cost pool" for each country as they are
incurred. The Company records depletion
 
                                       23
<PAGE>
of its full-cost pool using the unit of production method. To the extent that
such capitalized costs in each full-cost pool (net of depreciation, depletion
and amortization and related deferred taxes) exceed the present value (using a
10% discount rate) of estimated future net after-tax cash flows from proved oil
and gas reserves, such excess costs are charged to operations. Once incurred, a
write-down of oil and gas properties is not reversible at a later date. The
Company incurred such charges in the aggregate amount of $1.6 million and $1.5
million for the year ended December 31, 1995 and the nine months ended September
30, 1996, respectively, as a result of a determination that the Company's
aggregate investment in developed and abandoned projects exceeded the present
value of the Company's proved reserves as of December 31, 1995 and as of March
31, 1996 and June 30, 1996. The Company believes that its increasingly stringent
criteria for project selection which results in participation in higher quality
projects, its geographic focus in the Gulf Coast Region, its increasing base of
knowledge and experience, its ability to acquire unpromoted working interests
and its participation in a larger number of projects have made the probability
of future impairment writedowns less likely. However, no assurance can be given
that future impairment writedowns, which may be material in amount, will not be
incurred by the Company.
 
    The Company has recorded a valuation allowance against the estimated amount
of deferred tax assets for which realization is uncertain. The Company will
review the valuation allowance at the end of each quarter and will make
adjustments if it is determined that it is more likely than not that the
deferred tax assets will be realized. As of December 31, 1995, the Company had
tax net operating loss carryforwards ("NOL's") of $3,642,000 which begin to
expire in 2008. As a result of this Offering, there may be a limitation placed
on the Company's utilization of its NOL's by Section 382 of the Internal Revenue
Code of 1986, as amended. See Notes 3 and 13 to the Financial Statements of the
Company included elsewhere herein.
 
FINANCIAL STATEMENT ADJUSTMENTS
 
    Since the initial filing of the Registration Statement of which this
Prospectus forms a part (see Note 13 to the Financial Statements of the
Company), the Company has made certain changes to its prior period financial
statements. These changes have included:
 
    - Accrual of $51,000 of option compensation in 1995 and $639,000 in the
      nine-month period ended September 30, 1996 (see Note 7 to the Financial
      Statements of the Company), primarily to reflect the estimated intrinsic
      value of such option grants using the assumed initial public offering
      price of Common Stock as the estimate of fair value
 
    - Changes in the accrual of preferred stock dividends (Series A Preferred
      Stock and Series C Preferred Stock) to reflect their constructively
      cumulative nature (see Note 5 to the Financial Statements of the Company)
 
    - Refinements in the valuation, and related accretion, of preferred stock,
      to report such amounts at more precise estimates of fair values when
      issued (see Note 5 to the Financial Statements of the Company)
 
    The effects of these changes (none of which affected income tax amounts) on
previously reported financial statement items are as follows:
 
<TABLE>
<CAPTION>
                                                                                                     NINE MONTH
                                                              FOR THE YEAR ENDED DECEMBER 31,       PERIOD ENDED
                                                         -----------------------------------------  SEPTEMBER 30,
                                                            1993          1994           1995           1996
                                                         -----------  -------------  -------------  -------------
<S>                                                      <C>          <C>            <C>            <C>
Net loss:
  As originally reported...............................  $  (615,079) $    (385,013) $  (2,437,384)  $(1,949,808)
  Accrue option compensation...........................      --            --              (50,991)     (639,396)
                                                         -----------  -------------  -------------  -------------
  As currently reported................................  $  (615,079) $    (385,013) $  (2,488,375)  $(2,589,204)
                                                         -----------  -------------  -------------  -------------
                                                         -----------  -------------  -------------  -------------
</TABLE>
 
                                       24
<PAGE>
<TABLE>
<CAPTION>
                                                                                                     NINE MONTH
                                                              FOR THE YEAR ENDED DECEMBER 31,       PERIOD ENDED
                                                         -----------------------------------------  SEPTEMBER 30,
                                                            1993          1994           1995           1996
                                                         -----------  -------------  -------------  -------------
Net loss to common stockholders:
<S>                                                      <C>          <C>            <C>            <C>
  As originally reported...............................  $  (619,045) $    (918,780) $  (3,269,492)  $(2,789,613)
  Accrue option compensation...........................      --            --              (50,991)     (639,396)
  Change dividend accrual..............................      (52,790)        81,704       (275,256)      293,505
  Adjust preferred stock valuation and accretion.......      (10,387)      --             --             --
                                                         -----------  -------------  -------------  -------------
  As currently reported................................  $  (682,222) $    (837,076) $  (3,595,739)  $(3,135,504)
                                                         -----------  -------------  -------------  -------------
                                                         -----------  -------------  -------------  -------------
Pro Forma net loss per share:
  As originally reported...............................      N/A           N/A       $       (0.49)  $     (0.39)
  Accrue option compensation...........................                                       (.01)         (.12)
  Change dividend accrual..............................                                   --             --
  Changes in pro forma common shares outstanding and
    other..............................................                                        .03           .02
                                                                                     -------------  -------------
  As currently reported................................                              $       (0.47)  $     (0.49)
                                                                                     -------------  -------------
                                                                                     -------------  -------------
Accumulated deficit:
  As originally reported...............................  $  (619,045) $  (1,537,825) $  (4,807,317)  $(7,596,930)
  Accrue option compensation...........................      --            --              (50,991)     (690,387)
  Change dividend accrual..............................      (52,790)        28,914       (246,342)       47,163
  Adjust preferred stock valuation and accretion.......      (10,387)       (10,387)       (10,387)      (10,387)
                                                         -----------  -------------  -------------  -------------
  As currently reported................................  $  (682,222) $  (1,519,298) $  (5,115,037)  $(8,250,541)
                                                         -----------  -------------  -------------  -------------
                                                         -----------  -------------  -------------  -------------
Common stockholders' equity (deficit):
  As originally reported...............................  $    16,365  $    (740,937) $  (4,032,028)  $(6,789,729)
  Change dividend accrual..............................      (52,790)      --             (208,291)       85,214
  Adjust preferred stock valuation and accretion.......      --              66,965       --             --
                                                         -----------  -------------  -------------  -------------
  As currently reported................................  $   (36,425) $    (673,972) $  (4,240,319)  $(6,704,515)
                                                         -----------  -------------  -------------  -------------
                                                         -----------  -------------  -------------  -------------
</TABLE>
 
WORKING INTERESTS ACQUIRED SUBSEQUENT TO SEPTEMBER 30, 1996
 
    The Company continually reviews opportunities for participation in
exploration projects. Subsequent to September 30, 1996, the Company has acquired
working interests in the following additional projects:
 
<TABLE>
<CAPTION>
                                                                                               ANTICIPATED
                                                                         PROJECT        --------------------------
PROJECT LOCATION                                                    COMMENCEMENT DATE   ACQUISITION     DRILLING
- ------------------------------------------------------------------  ------------------  ------------  ------------
<S>                                                                 <C>                 <C>           <C>
Karnes Co., Texas.................................................  October 1996        $    255,000  $    296,000
Brazoria Co., Texas...............................................  November 1996            300,000       100,000
Matagorda Co., Texas..............................................  November 1996            334,000       220,000
Republic of Cote d'Ivoire.........................................  January 1997             508,700       480,000
                                                                                        ------------  ------------
  Total...........................................................                      $  1,397,700  $  1,096,000
                                                                                        ------------  ------------
                                                                                        ------------  ------------
</TABLE>
 
    The amounts described as "acquisition" include the estimated costs expected
to be incurred by the Company based on its respective working interest
percentage prior to drilling, specifically with respect to land acquisition and
seismic imaging. The amounts described as "drilling" are estimates of the
expenses that the Company anticipates incurring, based on its respective working
interest percentage, in connection with drilling of the first exploration well.
Future drilling costs will be dependent upon the success of the initial
exploration well, the target depths of wells and the number of wells drilled.
The Company is currently unable to predict or estimate with any certainty the
amounts of such expenditures.
 
                                       25
<PAGE>
RESULTS OF OPERATIONS
 
    The following table sets forth certain operating information of the Company
during the periods indicated:
 
<TABLE>
<CAPTION>
                                                                                                          NINE MONTH
                                                                                                        PERIODS ENDED
                                                                        YEAR ENDED DECEMBER 31,         SEPTEMBER 30,
                                                                    -------------------------------  --------------------
                                                                      1993       1994       1995       1995       1996
                                                                    ---------  ---------  ---------  ---------  ---------
<S>                                                                 <C>        <C>        <C>        <C>        <C>
PRODUCTION:
  Gas (MMcf)......................................................     --          105.1       97.1       73.3      117.8
  Oil and condensate (MBbls)......................................     --            6.1        6.7        4.5        6.5
  Total equivalent (MMcfe)........................................     --          141.7      137.3      100.3      156.8
 
AVERAGE SALES PRICE:
  Gas (per Mcf)...................................................     --      $    1.93  $    1.59  $    1.63  $    2.41
  Oil and condensate (per Bbl)....................................     --          16.58      17.89      18.35      19.17
 
AVERAGE EXPENSES (PER MCFE):
  Lease operating (1).............................................     --      $    0.24  $    0.57  $    0.44  $    0.33
  Depletion of oil and gas properties (2).........................     --           0.64       1.15       0.94       0.81
</TABLE>
 
- ------------------------
 
(1) Includes all direct expenses of operating the Company's properties, as well
    as severance and ad valorem taxes.
 
(2) Excludes depreciation and amortization of technical interpretation
    equipment, office furniture and equipment and office leasehold improvements,
    impairments of oil and gas properties and amortization of organization
    costs.
 
    NINE MONTH PERIOD ENDED SEPTEMBER 30, 1996 COMPARED TO THE NINE MONTH PERIOD
     ENDED SEPTEMBER 30, 1995
 
    OIL AND GAS REVENUES.  Oil and gas revenues increased by 102% to $408,000
for the nine months ended September 30, 1996 from $202,000 for the same period
of 1995. Of this increase, $114,000, or 55%, was attributable to an increase in
production and $92,000, or 45%, was attributable to an increase in the average
sales price for natural gas and oil. Production increased by 56% to
approximately 156.8 MMcfe for the nine months ended September 30, 1996, from
100.3 MMcfe for the comparable 1995 period. The increased production reflected
production for the entire nine months ended September 30, 1996 from the
successful wells drilled during the last six months of 1995. In addition,
production for the nine months ended September 30, 1996 included production from
a well completed in June 1996 and four successful wells completed in a single
project during July and August 1996. The average sales prices for oil increased
4% to $19.17 during the nine months ended September 30, 1996 from $18.35 for the
comparable 1995 period. The average sales price for natural gas increased by 48%
to $2.41 per Mcf for the nine months ended September 30, 1996 from $1.63 per Mcf
for the comparable 1995 period.
 
    LEASE OPERATING EXPENSE.  Lease operating expense increased by 16% to
$51,000 for the nine months ended September 30, 1996 from $44,000 for the
comparable 1995 period. This increase was primarily attributable to the increase
in 1996 production. Lease operating expense per Mcfe decreased by 25% to $0.33
for the nine months ended September 30, 1996 from $0.44 for the comparable 1995
period. Substantially all of the decrease in lease operating expense per Mcfe
was the result of the successful completion of four wells within a single
project during July and August 1996. These wells had lower lease operating costs
per Mcfe than wells from which production had been obtained in the comparable
prior period. The lower lease operating expense per Mcfe of the four wells
completed during July and August 1996 relate principally to the nature and
location of the completed wells. These four wells are producing from onshore,
shallow, highly permeable gas sands and produce relatively small amounts of
water, so there are negligible treating or disposal costs associated with such
wells. These completed wells require no
 
                                       26
<PAGE>
artificial lift or compression so that the power and maintenance costs
associated with such wells are minimal. Additionally, the highly permeable
nature of the producing zones results in relatively high production rates, which
lowers all fixed expenses associated with production from these wells on a per
Mcfe basis.
 
    By contrast, wells completed in prior periods, in general, have had higher
expenses due to the need for artificial lift and/or compression associated with
producing these wells. Also, many of the wells have produced water in addition
to hydrocarbons, resulting in additional expenses for treatment and disposal of
such fluid.
 
    Although the Company is unable to predict with certainty the lease operating
expense per Mcfe that may be incurred in the future, the Company does not
anticipate that such expenses on a per Mcfe basis will be in amounts less than
those which were incurred during the nine months ended September 30, 1996.
 
    DEPLETION, DEPRECIATION AND AMORTIZATION EXPENSE.  The major components of
depletion, depreciation and amortization are depletion of oil and gas properties
and administrative depreciation and amortization.
 
    Depletion of oil and gas properties for the nine months ended September 30,
1996 increased by 34% to $126,000 from $94,000 for the comparable period in
1995. The increase in depletion of oil and gas properties resulted from the
increase in oil and gas production. Depletion of oil and gas properties per Mcfe
for the nine months ended September 30, 1996 declined by 14% to $0.81 from $0.94
due to an increase in reserves at a faster rate in 1996 than the Company's full
cost pool of capitalized costs.
 
    Depreciation and amortization of technical interpretation equipment, office
furniture and equipment and office leasehold improvements increased 74% to
$337,000 for the nine months ended September 30, 1996 from $194,000 for the
comparable 1995 period. This increase was primarily attributable to the
acquisition of additional technical interpretation equipment and software with
an approximate cost of $422,000 during the nine months ended September 30, 1996.
 
    IMPAIRMENT OF OIL AND GAS PROPERTIES.  Oil and gas impairment charges
recorded as of March 31, 1996 and June 30, 1996 totaled approximately $1.5
million, primarily as a result of completion of the evaluation of two prospects
which had poor drilling results during these periods. The addition of the total
investment in these prospects to evaluated costs resulted in impairment charges
under the Company's accounting policy for oil and gas properties, as described
in Note 2 to the Financial Statements. As of September 30, 1996, there was a
downward revision in the Company's oil and gas reserve estimates as of January
1, 1996. Such revisions resulted from additional production and performance
information which first became available during 1996.
 
    The Company incurred similar oil and gas impairment charges during the nine
months ended September 30, 1995 of approximately $1.5 million.
 
    As a result of the completion of four wells in July and August 1996 and the
related increase in the Company's estimate of proved reserves, the present value
(using a 10% discount rate) of estimated future net after-tax cash flow from
proved oil and gas reserves exceeded the Company's aggregate investment in
developed and abandoned projects by approximately $800,000 as of September 30,
1996.
 
    GENERAL AND ADMINISTRATIVE EXPENSE.  General and administrative expense, net
of costs capitalized to exploration and development projects, increased by 106%
to $1,344,000 for the nine months ended September 30, 1996 from $653,000 for the
comparable 1995 period. This increase was primarily attributable to compensation
expense recognized in connection with stock options granted within one year of
the initial filing of the Registration Statement of which this Prospectus forms
a part, which expense is based on the difference between the option price and
the initial $14.00 per share estimate of the initial public offering price of
the Common Stock.
 
    RENTAL INCOME.  Rental income increased by 161% to $120,000 for the nine
months ended September 30, 1996 from $46,000 for the comparable 1995 period. The
Company derives rental income pursuant to an agreement to exchange use of
certain of the Company's technical and office equipment by an independent
seismic processing company for a percentage of the gross fee billings of such
seismic
 
                                       27
<PAGE>
processing company. As a result, the rental income recognized by the Company
varies significantly from period to period.
 
    INTEREST AND OTHER INCOME.  Interest and other income increased by 73% to
$218,000 for the nine months ended September 30, 1996 from $126,000 for the
comparable 1995 period, primarily as a result of an increase in short-term
investments made with the proceeds of the sale of Series C Preferred Stock.
 
    IMAGING EXPENDITURES.  The Company estimates that it expended approximately
$1.19 million during the nine months ended September 30, 1996 for pre-drilling
expenditures attributable to 3-D imaging. If 2-D rather than 3-D imaging
technology could have been used to identify the drill site locations, the
Company estimates that pre-drilling expenditures would have approximated
$291,000 based on the number of drill sites identified at the end of the period.
The Company has based such estimate on its assumption that three 2-D seismic
lines, each five miles in length, with an approximate cost of $5,000 per mile
for non-wetland on-shore projects and $10,000 per mile in wetland and offshore
projects would have been required to identify each drill site. However, no
assurance can be given that the cost incurred by the Company if it had actually
performed the 2-D seismic imaging would not be greater or lower than estimated.
 
    NET LOSS.  As a result of the foregoing, the Company's net loss increased by
24% to $2.6 million for the nine months ended September 30, 1996 from $2.1
million for the comparable 1995 period.
 
    YEAR ENDED DECEMBER 31, 1995 COMPARED TO YEAR ENDED DECEMBER 31, 1994
 
    OIL AND GAS REVENUES.  Oil and gas revenues decreased by 10% to $275,000 for
the year ended December 31, 1995 from $304,000 for the comparable 1994 period.
Of this decrease, $9,000 or 31% was attributable to a decrease in production and
$20,000 or 69% was attributable to a decrease in the average sales price for
gas. Production decreased by 3% to 137.3 MMcfe for the year ended December 31,
1995 from 141.7 MMcfe for the comparable 1994 period, primarily as a result of a
decline during 1995 in production from certain wells in the Bright Falcon
project as compared to 1994. The reduction in revenue attributable to a decline
in production from this particular project was partially offset by new
production from other wells completed in the last six months of 1995. The
average sales price for oil increased by 8% to $17.89 per Bbl during the year
ended December 31, 1995 from $16.58 per Bbl during the year ended December 31,
1994. The average sales price for gas decreased by 18% to $1.59 per Mcf during
the year ended December 31, 1995 from $1.93 per Mcf during the year ended
December 31, 1994.
 
    LEASE EXPENSE.  Lease operating expense for the year ended December 31, 1995
increased by 132% to $79,000 from $34,000 for the year ended December 31, 1994.
This increase was primarily attributable to workovers and higher lease operating
expenses relating to producing wells on the Bright Falcon project. Lease expense
per Mcfe increased to $0.57 during the year ended December 31, 1995 from $0.24
for the comparable 1994 period. Substantially all of the increase in lease
operating expense per Mcfe was related to the workovers and higher lease
operating expenses described above.
 
    DEPLETION, DEPRECIATION AND AMORTIZATION EXPENSE.  Depletion of oil and gas
properties for the year ended December 31, 1995 increased 74% to $158,000 from
$91,000 for the prior year. Depletion per Mcfe for the year ended December 31,
1995 increased 80% to $1.15 from $0.64 for the prior year. The increases in both
total depletion and depletion per Mcfe were the result of a downward revision in
the amount of 909 Mcfe in the Company's oil and gas reserves in 1995.
 
    Depreciation and amortization of technical interpretation equipment, office
furniture and equipment and office leasehold improvements increased by 140% to
$288,000 during the year ended December 31, 1995 from $120,000 for the
comparable 1994 period. This increase was due primarily to the acquisition
during 1995 of additional technical interpretation equipment and software with
an approximate cost of $620,000.
 
    IMPAIRMENT OF OIL AND GAS PROPERTIES.  The Company incurred oil and gas
property impairment charges during 1995 of $1.6 million. No such charges were
incurred in 1994. The 1995 charges resulted from the Company's determination
that its investment in developed and abandoned projects exceeded the
 
                                       28
<PAGE>
present value of the Company's proved reserves at December 31, 1995. The
impairment charges reflected the completion of the evaluation of two prospects
which had poor drilling results and a significant downward revision of oil and
gas reserve estimates in 1995. The primary factors contributing to the reserve
revision related to: (1) the premature loss of a well due to mechanical reasons
which was unanticipated at the time of the initial estimate, and (2) the removal
of "proved, undeveloped" reserves attributable to a well location, which the
project partners elected not to drill. Both of these revisions related to
prospects which were associated with the Bright Falcon project.
 
    GENERAL AND ADMINISTRATIVE EXPENSE.  General and administrative expense,
which is net of overhead capitalized to projects, increased by 51% to $905,000
for the year ended December 31, 1995 from $598,000 in the comparable 1994
period. This increase was primarily attributable to compensation expense for new
employees and compensation expense in the amount of $51,000 attributable to
stock options issued within one year of the initial filing of the Registration
Statement of which this Prospectus forms a part.
 
    RENTAL INCOME.  Rental income decreased by 43% to $58,000 for the year ended
December 31, 1995 from $101,000 for the comparable 1994 period. This decrease is
attributable to a decrease during 1995 in the gross fee billings of the seismic
processing company which utilizes certain of the Company's technical and office
equipment. The Company earns rental income by exchanging use of its equipment
for a percentage of the seismic processing company's gross fee billings.
 
    INTEREST AND OTHER INCOME.  Interest and other income increased to $236,000
for the year ended December 31, 1995 from $53,000 for the comparable 1994
period, as a result of an increase in short-term investments made with the
proceeds from the sale of Series C Preferred Stock.
 
    IMAGING EXPENDITURES.  The Company estimates that it expended approximately
$221,000 during the year ended December 31, 1995 for pre-drilling expenditures
attributable to 3-D imaging. If 2-D rather than 3-D imaging technology could
have been used to identify the drill site locations, the Company estimates that
pre-drilling expenditures would have approximated $116,000 based on the number
of drill sites identified during the period. The Company has based such estimate
on its assumption that three 2-D seismic lines, each five miles in length, with
an approximate cost of $5,000 per mile for non-wetland on-shore projects and
$10,000 per mile in wetland and offshore projects would have been required to
indentify each drill site. However, no assurance can be given that the cost
incurred by the Company if it had actually performed the 3-D seismic imaging
would not have been greater or lower than estimated.
 
    NET LOSS.  As a result of the foregoing, the Company's net loss increased to
$2.5 million for the year ended December 31, 1995 from $385,000 for the year
ended December 31, 1994.
 
    YEAR ENDED DECEMBER 31, 1994 COMPARED TO YEAR ENDED DECEMBER 31, 1993
 
    OIL AND GAS REVENUES AND EXPENSES.  Oil and gas revenues were $304,000 for
the year ended December 31, 1994. Production during 1994 was 141.7 MMcfe. No oil
and gas revenues, operating expenses or depletion of oil and gas properties were
recognized by the Company in 1993.
 
    Depreciation and amortization of technical interpretation equipment, office
furniture and equipment and office leasehold improvements increased by 85% to
$120,000 for the year ended December 31, 1994 from $65,000 for the comparable
1993 period. This increase was primarily attributable to the acquisition during
1994 of additional technical interpretation equipment with an approximate cost
of $227,000.
 
    RENTAL INCOME.  Rental income decreased by 20% to $101,000 for the year
ended December 31, 1994 from $127,000 for the comparable 1993 period.
 
    INTEREST AND OTHER INCOME.  Interest and other income increased to $53,000
for year ended December 31, 1994 from $8,000 during the comparable 1993 period.
This increase is primarily attributable to the short term investment of the
proceeds of the sale of the Units.
 
    IMAGING EXPENDITURES.  The Company estimates that it expended approximately
$381,000 during the year ended December 31, 1994 for pre-drilling expenditures
attributable to 3-D imaging. If 2-D rather than
 
                                       29
<PAGE>
3-D imaging technology could have been used to identify the drill site
locations, the Company estimates that pre-drilling expenditures would have
approximated $103,000 based on the number of drill sites identified during the
period. The Company has based such estimate on its assumption that three 2-D
seismic lines, each five miles in length, with an approximate cost of $5,000 per
mile for non-wetland on-shore projects and $10,000 per mile in wetland and
offshore projects would have been required to indentify each drill site.
However, no assurance can be given that the cost incurred by the Company if it
had actually performed the 2-D seismic imaging would not have been greater or
lower than estimated.
 
    NET LOSS.  Primarily as a result of the foregoing, the Company's net loss
decreased by 37% to $385,000 for 1994 from $615,000 for the comparable 1993
period.
 
LIQUIDITY AND CAPITAL RESOURCES
 
    At September 30, 1996, the Company had working capital in the amount of $3.4
million. To date, the Company has funded its oil and gas exploration activities
principally through cash provided by the sale of equity securities.
 
    The Company was initially capitalized in January 1993 through (i) the
issuance and sale of 768,117 shares of Common Stock to the Company's three
founders and (ii) the issuance of 100,000 shares of Series A Preferred Stock to
Landmark Graphics for total consideration valued by the Company and Landmark
Graphics to be $500,000. The Series A Preferred Stock was initially convertible
into 517,000 shares of non-voting Common Stock that was similar in all other
respects to the Common Stock. As part of the consideration for the Series A
Preferred Stock, Landmark Graphics guaranteed a $400,000 bank loan for the
Company. In November 1993 and October 1994, the Company raised additional
capital in the amount of $5.4 million through the sale of 54,000 Units.
Immediately prior to the sale of the Units, the Company had a working capital
deficit of $768,588 and an equity deficit of $55,141 and did not believe that
financing alternatives for funding of the Company's planned capital expenditures
and exploration activities except for the sale of Units were available. As a
condition to their investment, the prospective purchasers of Units required
Landmark Graphics to convert the Series A Preferred Stock to 329,003 shares of
Common Stock rather than the 517,000 shares which Landmark Graphics was entitled
pursuant to the original terms of the Series A Preferred Stock. Rather than
being required to perform under its guarantee, Landmark Graphics agreed to
convert the shares of Series A Preferred Stock which it owned, accepting the
reduced number of shares of Common Stock. The prospective Unit purchasers (who
were unaffiliated with each of the Company and Landmark Graphics) required
Landmark Graphics to convert its shares of Series A Preferred Stock on the terms
described above to effect an increase in such persons' prospective ownership in
the Company. Additional capital in the amount of $8.0 million was raised by the
Company in a private placement of Series C Preferred Stock during the third
quarter of 1995. Shortly after the sale of the Series C Preferred Stock was
completed, the Company completed a review and analysis of its estimated oil and
gas reserves and concluded that a downward revision in its estimates was
appropriate since certain proved undeveloped reserves were no longer considered
likely to be recoverable. To compensate the investors who had purchased Series C
Preferred Stock, each purchaser was issued warrants to purchase additional
shares equal to 10% of the number of shares of Series C Preferred Stock such
investor had purchased. See "The Company."
 
    The Series B Preferred Stock accrues dividends (in cash or in shares of
Series B Preferred Stock, as determined by the Board of Directors) at an annual
rate per share of $12.50 if in cash or .13276 shares of Series B Preferred Stock
if in stock, payable annually on December 31. Assuming the dividend is paid in
cash, the aggregate annual dividend on the issued and outstanding Series B
Preferred Stock approximates $836,000. The Company is obligated to redeem all of
the issued and outstanding Series B Preferred Stock in two installments
commencing on November 9, 2002 at a redemption price of $100 per share. To
eliminate the accrual of dividends for years subsequent to December 31, 1995,
the Company has elected to use a portion of the net proceeds of this Offering to
redeem all of the issued and outstanding shares of Series B Preferred Stock. See
"Use of Proceeds."
 
                                       30
<PAGE>
    The Company's net loss of $2.6 million for the nine months ended September
30, 1996 included non-cash expenses comprised of impairment of oil and gas
properties in the amount of $1.5 million, compensation expense in the amount of
$600,000 related to stock options granted within one year of the initial filing
of the Registration Statement of which this Prospectus forms a part, and
depletion, depreciation and amortization in the amount of $464,000.
 
    Net cash used in investing activities for the nine months ended September
30, 1996 was $1.8 million. The acquisition, exploration and development of oil
and gas properties in the amount of $2.9 million was the principal use of cash
in the Company's investing activities. The principal source of cash from the
Company's investing activities was the maturity of debt securities totaling $1.6
million.
 
    The Company has no outstanding long-term debt and is not a party to any debt
or collateral-based lending arrangements. The Company has never utilized
commodity swaps for its oil and gas production and it does not anticipate doing
so in the foreseeable future. In addition, the Company has not entered into any
hedging transactions and has no current intention to do so in the future.
 
    The development of the Company's business has in the past required
substantial oil and gas capital expenditures. To meet its goal, the Company in
the future will be required to make oil and gas capital expenditures
substantially in excess of historical levels to acquire, explore and develop oil
and gas properties. See "Risk Factors--Substantial Capital Requirements and
Liquidity." Capital expenditures for oil and gas exploration and production
activities during 1993, 1994, and 1995, and for the nine months ended September
30, 1996, were $0.8 million, $1.8 million, $2.2 million and $2.9 million,
respectively. Capital expenditures for oil and gas exploration for the three
months ended December 31, 1996 are expected to be approximately $2.1 million and
budgeted capital expenditures for the Company's oil and gas exploration and
production activities during 1997, assuming completion of this Offering, are
currently estimated to be approximately $14.9 million. See "Risk Factors--Broad
Discretion over Use of Proceeds" and "Use of Proceeds."
 
    As a result of the Company's periodic review of each of its portfolio of oil
and gas exploration and development properties and its available capital, the
Company has on two occasions sold partial interests in specific oil and gas
projects to other investors to reduce its total investment commitment to such
projects. In each such instance, the Company sold one-half and two-thirds of its
working interests in such projects, respectively, in exchange for proceeds in an
amount approximating one-half and two-thirds of the costs incurred by the
Company in connection with such projects, respectively. No gain or loss was
recognized on either transaction.
 
    Although the Company presently has no current commitment to sell all or any
portion of its working interests, such sales could be used as a source of
liquidity by the Company in the future.
 
    The Company expects that its available cash, expected cash flows from
operating activities, and the proceeds from the Offering will be sufficient to
meet its financial obligations and fund its planned exploration and drilling
activities for the short term (which is considered by the Company to be the
twelve months following the consummation of the Offering), PROVIDED, that (i)
there are no significant declines in oil and gas prices below current levels or
anticipated seasonal lows, (ii) there are no significant declines in oil and gas
production from existing properties other than declines in production currently
anticipated based on engineering estimates of the decline curves associated with
such properties and (iii) the Company is able to discover and produce commercial
quantities of oil and gas and within the time frame the Company has predicted.
The Company intends to satisfy its long-term liquidity requirements from a
combination of expected cash flow generated from operations, borrowings from
financial institutions (which may be secured by the Company's oil and gas
reserves) and from future public or private offerings of equity and/or debt
securities. For liquidity purposes, the Company considers "long-term" to be the
second, third and fourth twelve month periods following the consummation of the
Offering.
 
    In the event the cash flows from the Company's operating activities and the
net proceeds from the Offering are not sufficient to fund development and
exploration expenditures, or results from developmental drilling are not as
successful as anticipated, the Company will be required to modify the
implementation
 
                                       31
<PAGE>
of its operating strategy unless additional financing is available. There can be
no assurance such financing would be available on terms which would be
acceptable to the Company. See "Risk Factors--Substantial Capital Requirements
and Liquidity."
 
EFFECTS OF INFLATION AND CHANGES IN PRICE
 
    The Company's results of operations and cash flows are affected by changing
oil and gas prices. If the price of oil and gas increases (decreases), there
could be a corresponding increase (decrease) in the operating cost that the
Company is required to bear for operations, as well as an increase (decrease) in
revenues. Inflation has had a minimal effect on the Company.
 
OTHER
 
    In connection with stock options granted within one year of the initial
filing of the Company's registration statement, the Company has recorded
deferred compensation expense based on the difference between the option prices
and the fair value of the Company's common stock at the date of grant (using the
initial $14.00 per share estimate of the initial public offering common stock
price as an estimate of the fair value). As of September 30, 1996, the Company
had unamortized deferred compensation of $1,529,773 which will be charged to
expense during the next four years. Had the Company used the acutal offering
price of $11.00 per share to compute the deferred compensation resulting from
the difference between such option exercise prices and the fair value of the
Company's common stock, the September 30, 1996 financial statements would
reflect the following reductions:
 
<TABLE>
<CAPTION>
Deferred compensation related to stock options....................  $ 341,983
<S>                                                                 <C>
Paid-in capital                                                       496,320
Accumulated deficit & Net loss....................................  $ 154,337
</TABLE>
 
    In March 1995, the Financial Accounting Standards Board issued Statement of
Financial Accounting Standards No. 121 ("SFAS No. 121") regarding accounting for
the impairment of long-lived assets. The Company adopted SFAS No. 121 effective
January 1, 1996. However, such adoption did not affect the primary test of asset
recoverability because the Company's oil and gas properties are accounted for
under the full cost method of accounting, as discussed in Note 2 to the
Financial Statements of the Company. The adoption of SFAS No. 121 had no effect
on the Company's results of operations for the nine month period ended September
30, 1996.
 
    In October 1995, the Financial Accounting Standards Board issued Statement
of Financial Accounting Standards No. 123 ("SFAS No. 123"). SFAS No. 123 is a
new standard of accounting for stock-based compensation and establishes a fair
value method of accounting for awards granted after December 31, 1995 under
stock compensation plans. SFAS No. 123 encourages, but does not require for
employees, companies to adopt the fair value method of accounting in place of
the existing method of accounting for stock-based compensation whereupon
compensation costs are recognized only in situations where stock compensation
plans award intrinsic value to recipients at the date of grant.
 
    The Company has elected not to adopt the fair value accounting of SFAS No.
123 for employees and continues to account for these plans under APB Opinion No.
25.
 
                                       32
<PAGE>
                                    BUSINESS
 
OVERVIEW
 
    3DX Technologies is a knowledge-based oil and gas exploration company whose
core competence and strategic focus is the utilization of 3-D seismic imaging
and other advanced technologies in the search for commercial quantities of
hydrocarbons. The Company only enters into arrangements that enable it to
combine its expertise and exploration capabilities with the operating skills of
other oil and gas companies. The Company participates in carefully selected
exploration projects as a non-operating, working interest owner, sharing both
risks and rewards with its partners. The Company commenced operations in January
1993 to take advantage of perceived opportunities emerging from changes in the
domestic oil and gas industry, including the divestiture of domestic oil and gas
properties, advances in technology and the outsourcing of specialized technical
capabilities. By reducing drilling risk through 3-D imaging and analysis, the
Company seeks to improve the expected return on investment in its oil and gas
projects.
 
    The Company has developed a rigorous screening process that it applies to
all projects that it considers. The screening process, adapted continually to
incorporate the Company's ongoing experience, is designed to produce a balanced
portfolio of select projects that have reliable and experienced operating
partners, are conducive to the application of advanced 3-D technology, have
significant upside potential and may be extended into exploration trends.
 
    As of the date of this Prospectus, the Company's current portfolio includes
12 active operator partners and 24 exploration projects primarily located
onshore and near shore within the Gulf Coast region from south Texas to southern
Florida. Although the Company's current geographic focus is principally the Gulf
Coast region, the Company has and will continue to pursue opportunities that may
become available in other select geographic areas as its capital resources
increase.
 
    The Company believes that it can effectively and efficiently participate in
an increasing number of concurrent projects by continually improving its
techniques for acquiring and analyzing data. One example of such an improvement
is the Company's 3DXPRESS process, an innovative exploration technique that
improves the quality of seismic data and significantly compresses the time frame
traditionally required for acquisition, processing, imaging and analysis. This
process allows analysis of 3-D data while the seismic survey is being conducted,
giving the Company's explorationists the ability to ensure data quality and
steer data collection toward more promising prospective areas. Utilizing this
technology, the Company has been able to image and analyze a larger number of
projects concurrently and to identify potential drilling sites more rapidly and
accurately.
 
    Since its formation through the date of this Prospectus, the Company has
participated in the drilling of 32 gross wells that have been drilled based on
the Company's site and target depth recommendations. Twenty of these wells were
successful and discovered estimated proved reserves of 40.3 Bcfe (2.8 Bcfe net
to the Company's interest), of which 27.0 Bcfe (2.1 Bcfe net to the Company's
interest) were discovered during the first nine months of 1996. The Company
currently expects to participate in the drilling of between 35 and 40 wells
during 1997, although the number of wells may increase as additional projects
are added to the Company's portfolio. The Company believes that the disciplined
approach it utilizes to select its projects, together with its technological
expertise will result in improved exploration success and project economics.
This success should position the Company to acquire larger working interests in
an increasing number of exploration projects.
 
STRATEGY
 
    The Company's goal is to increase its proved reserves, production and cash
flow by quickly, accurately and economically locating commercial quantities of
hydrocarbons for itself and its partners. To reach its goal, the Company is
pursuing a business strategy that includes the following principal elements:
 
    FOCUSING OPERATIONAL EFFORTS EXCLUSIVELY ON THE COMPANY'S EXPERTISE IN 3-D
IMAGING AND ANALYSIS.  The Company focuses all of its technical resources on
obtaining the best possible subsurface image and on
 
                                       33
<PAGE>
identifying the most effective location and target depth for each prospective
well. To allow it to focus its efforts exclusively on 3-D imaging and analysis,
the Company relies on its project partners to undertake the project's other
operating functions, including land acquisition, drilling and marketing. The
Company believes that its methods of applying 3-D imaging and analytical
technology provide it with knowledge and information superior to that produced
by companies engaged in many aspects of finding and producing oil and gas.
Although 3-D seismic technology is now routinely used in oil and gas exploration
projects, the Company believes that its focus, experience and innovative methods
of applying the technology provide it with advantages in extracting useful
information from seismic and other data.
 
    DEVELOPING AND SUPPORTING A TEAM OF TECHNOLOGICALLY SOPHISTICATED
EXPLORATIONISTS.  The Company believes that the quality of information obtained
from its application of 3-D imaging is dependent to a large extent on its
ability to capitalize on the intelligence, acquired knowledge and creativity of
the experienced geoscientists and engineers it employs. These experts have broad
expertise and experience from their collective participation in over 300 3-D
seismic projects in diverse geologic trends throughout the world. To allow the
Company to capitalize fully on the intellectual resources offered by such
experts, the Company's administrative operations and infrastructure are directed
toward providing tools and support to the Company's technical specialists. To
enhance its ability to recruit, retain and motivate such experts, the Company is
committed to providing its oil and gas finding geoscientists and engineers with
the most advanced imaging and analytical technology commercially available and
awards options to purchase Common Stock to each of its experts and other
employees.
 
    MAINTAINING A RESEARCH PROGRAM TO DEVELOP INNOVATIVE APPLICATION TECHNIQUES
INVOLVING ADVANCED EXPLORATION TECHNOLOGY.  The Company relies upon its ongoing
research to continually develop and adapt technology that the Company believes
will enable it to retain its position as a leading high technology exploration
company. For example, through its research efforts, the Company has developed
the 3DXPRESS process. The Company's 3DXPRESS process is an innovative technique
used in exploration that improves the quality of seismic data and significantly
compresses the time frame traditionally required for acquisition, processing,
imaging and analysis. This process allows analysis of 3-D data while the survey
is being conducted, giving the Company's explorationists the ability to ensure
data quality and steer data collection toward more areas where prospects are
more likely to exist. Utilizing this technology, the Company has been able to
image and analyze a larger number of projects concurrently and identify
potential drilling sites more rapidly and accurately. This ability to effect
near-real time acquisition, processing and analysis of seismic data allows the
Company to achieve optimum data and image quality, resulting in an improved
ability to economically locate commercial quantities of hydrocarbons. The
Company also believes that its application of emerging technologies, such as
migration velocity analysis and depth migration technology, provides the Company
with a competitive advantage in its ability to effectively and efficiently
locate commercial quantities of hydrocarbons.
 
    PURSUING A DISCIPLINED APPROACH TO SELECTIVE PROJECT PARTICIPATION,
PARTNERING AND DRILLING EFFORTS.  The Company adheres to the strict application
of its rigorous screening process and, based on its experience, continually
adapts the selection criteria to ensure that the Company participates only in
those projects that are likely to maximize the return on its capital investment.
The Company considers high quality projects to be projects that: (i) are managed
by reliable and successful operating partners; (ii) are located on properties to
which 3-D imaging can be effectively applied to evaluate the primary geologic
risk; (iii) have high upside potential; (iv) may be extended into trend plays;
and (v) have projected rates of return which make the production of hydrocarbons
economically attractive.
 
    ACTIVELY MANAGING THE COMPANY'S PORTFOLIO OF OIL AND GAS PROJECTS.  The
Company has developed and actively manages a balanced portfolio of partners,
projects and producing assets having a diverse range of risk/reward ratios.
Active portfolio management enables the Company to reduce its exposure to non-
geologic project risks such as land acquisition, operator performance and
drilling operations that are not mitigated by the application of 3-D imaging and
analysis technologies. In addition, the Company believes
 
                                       34
<PAGE>
that aggressive management of its portfolio enables it to maximize its use of
available capital by limiting the Company's exposure to any individual
exploration project and by allowing it to focus its resources toward trend play
opportunities arising from carefully selected projects. In exploration trends,
the Company is generally able to obtain a larger working interest than it
possessed with respect to its initial project investment.
 
PROJECT SELECTION AND MANAGEMENT METHODOLOGY
 
    Successful application of the Company's business plan is dependent upon the
Company's participation as an active working interest partner in select high
quality projects. The working interest acquired by the Company in any project is
determined through negotiation among the Company and its prospective partners
prior to the Company's commitment to participate. The percentage working
interest which the Company seeks to acquire varies with each project and is
dependent upon the project's anticipated costs, risk and potential return.
During the course of the project, the Company's working interest is subject to
change as a result of negotiated cost and working interest sharing arrangements,
the terms of which are known to the Company prior to its commitment to
participate. To identify these projects, the Company undertakes a rigorous
evaluation of the numerous projects proposed to it by its existing partners and
other project generators. The Company engages in the following steps to
evaluate, identify and manage high quality projects in which the Company
participates.
 
    - INITIAL SCREENING. Prior to committing technical resources to the
      evaluation of a potential project, the Company's business development team
      reviews both the potential project and its partners to determine if they
      satisfy certain initial business criteria. During the first nine months of
      1996, the Company reviewed 78 potential projects, of which 17 met the
      Company's basic business initial screening criteria. Subsequent to
      September 30, 1996 through the date of this Prospectus, the Company has
      reviewed 14 additional potential projects of which eight met the Company's
      basic business initial screening criteria. To evaluate a potential
      project, the Company considers geographic location, scale, geological
      model, anticipated drilling prospects, number of pay zones and trend
      potential and expected project economics. To evaluate a potential partner,
      the Company considers that partner's financial stability, reputation and
      record of success in exploration and production activities.
 
    - TECHNICAL EVALUATION. If the project satisfies the Company's initial
      business screening criteria, it is then evaluated by a multidisciplinary
      team of the Company's technical experts. Such technical evaluation allows
      the Company to analyze and evaluate further the basic geological model,
      determine the seismic character of reservoirs within the project site,
      determine if the application of 3-D imaging technology will adequately
      address the primary geologic risk, investigate local and regional
      production trends for target reservoirs, refine its evaluation of project
      economics and determine if the capital required conforms to the Company's
      investment guidelines. If the project meets these criteria, the Company
      will participate in the project, committing its capital, technological
      resources and 3-D imaging and analytical expertise.
 
    - EARTH IMAGING. Once a project is approved for investment, the project
      team, led by one of the Company's geoscientists or engineers and including
      representatives of all or substantially all of the project's partners,
      commences its efforts to create the most accurate subsurface image
      possible. By integrating 3-D seismic data with other geologic and
      engineering data, the project team uses the derived subsurface image to
      model all potential reservoirs within the project's area. The data
      collection, processing and analysis are managed by the Company to assure
      its integrity and consistency.
 
    - DRILLING DECISION. After the project team completes the earth imaging and
      analysis of a selected project, the project team determines if the
      applicable data identify economically attractive drilling opportunities.
      The economic return expected from drilling must satisfy certain criteria
      and must be
 
                                       35
<PAGE>
      commensurate with the perceived risk. Thereafter, the project team makes
      recommendations to the partnership regarding drill sites and target
      depths.
 
    - POST-DRILLING APPRAISAL. Subsequent to the drilling of each well in a
      project, the Company integrates the information it has acquired in the
      drilling phase with its earth model enabling it to enhance the model based
      on the best available data and knowledge. As a result, the Company builds
      an increasing base of knowledge upon which to make future drilling
      decisions with respect to each project.
 
    As a working interest partner, the Company shares all project costs in
proportion to its working interest percentage. In instances in which exploration
and development activities are unsuccessful, the Company incurs a loss equal to
its proportionate share of project costs prior to the time the project is
abandoned. Similarly, the Company will incur a loss if the Company's
proportionate share of revenue generated from production is insufficient to
cover the Company's share of project costs.
 
    The Company believes that its application of increasingly stringent criteria
for project selection which results in participation in higher quality projects,
its geographic focus in the Gulf Coast Region, its increasing base of knowledge
and experience, its ability to acquire unpromoted working interests and its
participation in a larger number of projects have made the probability of future
impairment writedowns less likely. However, no assurance can be given that
future impairment writedowns, which may be material in amount, will not be
incurred by the Company.
 
PROJECT GENERATION
 
    By its participation in multiple projects, many with multiple partners, the
Company seeks to demonstrate its ability to improve project economics. Its
current partners are its best resource for future high quality projects. The
Company believes that its existing partners, which have benefited from the
Company's ability to improve project economics by reducing primary geologic
risk, will seek such benefits with respect to future projects and will therefore
solicit the Company's involvement in such new projects. By participating in
projects with partners possessing experience and knowledge in exploration
operations that are complementary to the Company's imaging and analytical focus
area, the Company believes that it and each project partner receive the benefit
of the other's knowledge and expertise while achieving results that are greater
than any particular partner might be able to achieve independently. The Company
further believes that establishing long-term partner relationships will enhance
the flow of prospective opportunities and the quality and stability of the
business relationship, as well as reduce significant risks, such as the
partner's operating capabilities and financial stability.
 
SIGNIFICANT PROJECTS AND PROPERTIES
 
    The Company's exploration activities are currently focused on three Gulf
Coast trends, the Texas Gulf Coast trend, the Mississippi/Alabama trend and the
Sunniland trend. In addition, the Company is pursuing select projects in South
Louisiana and recently has elected to participate in its initial international
project located in the Republic of Cote d'Ivoire. Geologically, 3-D imaging of
the structural and stratigraphic complexities common in the Gulf Coast provides
the Company with an ability to identify significant hydrocarbon potential in and
around existing fields that could not be detected with 2-D and conventional
exploration techniques. Due to geologic complexities within this region, it may
be possible to identify multiple prospects within a single project. These
prospects typically offer multiple drilling opportunities with individual wells
capable of encountering multiple reservoirs. As its capital resources increase,
the Company believes it can extend its trend strategy into other select
geographic areas where the application of 3-D imaging technology can be utilized
to reduce the primary geological risks prior to drilling.
 
    Technically, the extensive drilling history within Gulf Coast trends
provides a powerful subsurface and production database to which seismic data can
be calibrated. These data provide the foundation required to design a seismic
program that optimizes resolution at targeted reservoirs. These data, when
combined
 
                                       36
<PAGE>
with 3-D seismic data, provide a more accurate assessment of reservoir quality,
productivity and reserve potential and in some instances, fluid type.
 
    The following sets forth a brief summary of the Company's exploration trend
areas and significant projects and properties. Although the Company is
aggressively pursuing activities in each of the following areas, there can be no
assurance that drilling opportunities will be identified or, if drilled, will be
successful.
 
    TEXAS GULF COAST TREND
 
    In the Texas Gulf Coast trend, the Company anticipates drilling between 20
to 30 gross wells in 1997 with budgeted capital expenditures approximating $10
to $15 million net to the Company's working interest. The Company and its
partners control in excess of 93,000 gross acres in this trend. Since February
1996 through the date of this Prospectus, the Company and its partners have
drilled seven wells in the trend, six of which have encountered commercial
quantities of oil and gas and are currently drilling one additional well. The
Company has successfully utilized the 3DXPRESS process on 8,400 acres overlying
four of these discoveries. At September 30, 1996, production rates for these
four wells totaled approximately 9.0 MMcfe/d. The Company is currently utilizing
the 3DXPRESS process on three other 3-D imaging programs totaling approximately
143 square miles in the trend. The Company's working interests in this trend
currently range from 6% to 40%.
 
    The Texas Gulf Coast trend includes both onshore and offshore properties and
generally extends along the Texas coast from Houston south to the Mexican
border. Prospective geology in the trend is characterized by numerous stacked
sand formations that were deposited continuously by river channels and deltas.
The trend's primary historical oil and gas producing formations include the
Wilcox, Frio, Yegua and Miocene.
 
    Certain of the projects the Company is pursuing in the Texas Gulf Coast
trend are described below:
 
        COVE AND MCPAC FIELDS.  The Company proposed and drilled a well with its
    partner, Bellwether Exploration Company, into a new fault block of the Cove
    and McPac Fields in August 1996 and discovered commercial quantities of oil
    and gas in two reservoirs. The well currently is shut-in but is expected to
    be flowing into existing production facilities by year end. The Company owns
    a 7% working interest in the well. In addition, the Company has defined a
    separate prospect adjacent to these fields and currently is evaluating
    whether to drill a well to test the prospect. The Cove and McPac Fields'
    acreage is held by production and is located in Matagorda Island Block
    487-L, Texas state waters, 96 miles southwest of Houston in 60 feet of
    water.
 
        GILA BEND.  The Company joined its partner, Ameritex Ventures, Ltd., in
    the project in December 1995. Integration of a 16-square mile 3-D seismic
    survey with the geology and production data resulted in a well being spud in
    July 1996. This well discovered four distinct pay zones of oil and gas and
    currently is producing 3.9 MMcfe and 80 Bbls of condensate per day from the
    first of the four pay zones. The Company and its partners control 3,525
    gross acres in Gila Bend, and the Company owns working interests ranging
    from 6% to 10%.
 
        GERONIMO.  The Company completed acquisition of a 77-square mile 3-D
    seismic survey in October 1996 utilizing the 3DXPRESS process in the
    Geronimo project, which is located in San Patricio County, Texas. Primary
    target formations include the Frio and Vicksburg sands, which are currently
    producing in fields in the area. The project area covers approximately
    25,000 gross acres in which the Company owns a 15% working interest. The
    Company's partners in this project include Esenjay Petroleum Corporation
    ("Esenjay").
 
        BRIGHT FALCON.  The Company joined its partner, Cox & Perkins
    Exploration, Inc., in 1993, in the Bright Falcon project, the Company's
    first project in the Texas Gulf Coast trend. Since then, the
 
                                       37
<PAGE>
    Company and its partner have drilled seven wells, five of which were
    discoveries. As of the date of this Prospectus, three wells, one of which
    was recompleted in November 1996, are producing in the Bright Falcon
    project. The Bright Falcon wells were drilled into Yegua and Frio gas
    formations after a 26-square mile 3-D seismic survey covering the Lost
    Bridge-Bright Falcon fields was analyzed by the Company. The project is
    located in Jackson County, Texas and its acreage is held by production. The
    Company owns a 17% working interest in this project.
 
    MISSISSIPPI/ALABAMA TREND
 
    In the Mississippi/Alabama trend, the Company anticipates drilling six to
eight gross wells in 1997 with budgeted capital expenditures approximating $2.5
million net to the Company's working interest. The Company and its partner,
Esenjay, control over 41,000 gross acres in the trend. The Company completed
acquisition of a 3-D seismic survey utilizing the 3DXPRESS process on a
64-square mile area in November 1996. The Company's first well in this trend is
expected to spud in the first quarter of 1997. The Company currently has a
working interest of approximately 15% in its properties in the trend.
 
    The Mississippi/Alabama trend includes onshore properties and generally
extends across a seven-county area from Newton County in Southern Mississippi
eastward through Southern Alabama to the Florida border. Prospective geology in
the trend is characterized by discrete occurrences of basement and salt-related
features that deform shallower sand formations to create potential structural
traps for oil and gas. The primary historical oil and gas producing formations
in the trend have been the Cotton Valley, Lower Haynesville, Smackover and
Norphlet.
 
    SUNNILAND TREND
 
    The Company's partner in the Sunniland trend project is Plains Resources,
Inc. ("Plains"). As part of its anticipated initial exploration of the Sunniland
trend in 1997, the Company plans to acquire a 3-D survey utilizing the 3DXPRESS
process and to drill a well on a prospect that the Company believes may confirm
an extension of the Raccoon Point Field. Cumulative production from this field,
located in Collier County, Florida, has exceeded 9.5 MMBOE. The Company and its
partner currently are exploring other 3-D project opportunities within the
Sunniland trend by acquiring, reprocessing and analyzing 2-D seismic data along
with other evaluation methods. The Company and its partner control approximately
81,000 gross acres in the trend. The Company owns an 8% working interest therein
excluding the currently established production.
 
    The Raccoon Point Field is within the Cretaceous Sunniland Trend, which
extends from south of Ft. Myers, Florida to northwest of Miami, Florida.
Prospective geology in the trend is characterized by carbonate reefs and shoals.
The trend's primary historical oil and gas producing formation is the Sunniland
formation.
 
    SOUTH LOUISIANA PROJECTS
 
        FOUR ISLE DOME.  To the date of this Prospectus, the Company has
    identified multiple drilling targets in the upper Miocene zone of Four Isle
    Dome, located in Terrebone Parish, Louisiana. The first of these wells in
    which the Company owned a 20% working interest was spud by the Company and
    its partner, Plains, in October 1996 targeting the upper Miocene at an
    approximate depth of 14,000 feet. Although the primary objective sands were
    encountered, electric logs indicated that those sands would not produce
    commercial quantities of hydrocarbons. The Company also is participating
    with Plains in an additional well scheduled to be drilled in December 1996.
    Prior to the Company's involvement in the project, Plains and its partners
    acquired a 51-square mile 3-D seismic survey in late 1995. In February 1996,
    the Company signed a joint venture agreement with Plains covering Four Isle
    Dome. Since then, the Company has assisted with completion of the seismic
    processing, has analyzed
 
                                       38
<PAGE>
    the seismic data and has identified drilling targets. The Company and its
    partner control approximately 19,000 gross acres on this project. The
    Company will own a 5% working interest in the well to be spud in December
    1996.
 
        HAYES.  The Company and its partner, Alta Mesa Resources, Inc. expect to
    spud the first well in the Hayes project during the first quarter of 1997.
    The Company has analyzed a 25-square mile 3-D seismic survey utilizing the
    3DXPRESS process. The survey area included the Hayes Field and selected
    adjacent acreage in Calcasieu and Jefferson Davis Parishes, Louisiana.
    Cumulative production from the Hayes Field has exceeded 157 Bcf and 1.64
    MMBbls. The Company does not own an interest in the field, but the Company
    believes that it has identified several drilling targets on the adjacent
    acreage. The Company and its partner control over 7,800 gross acres in this
    project in which the Company owns a 10% working interest.
 
        RACELAND.  The Company and its partner, Texoil, Inc., plan to drill the
    first exploratory well, targeted at Miocene formations, in the Raceland
    project during the first quarter of 1997. The Raceland project is located
    near the Raceland Field in Lafourche Parish, Louisiana. Acquisition of a
    64-square mile 3-D seismic survey on the underlying salt dome was completed
    in August 1996 and the Company currently is analyzing the seismic data. The
    nearby Raceland Field has produced over 24 MMBbls and 134 Bcf from Miocene
    sands at depths of 7,000 feet to 16,000 feet. The Company and its partner
    control over 17,000 gross acres in the Raceland project in which the Company
    owns a 5% working interest.
 
        EAST CAMERON 42.  The Company and its partners, Gulf Star Energy, Inc.
    and Santa Fe Energy Resources, Inc., drilled a gas discovery in Miocene
    sands on East Cameron 42, the Company's Hollywood project, in July 1996. The
    well is scheduled to be connected to existing production facilities in
    December 1996. East Cameron 42 is located in federal waters approximately
    175 miles southwest of New Orleans in 45 feet of water. The project acreage
    is held by production, and the Company owns a 5% working interest in this
    well.
 
OTHER PROJECTS
 
        LANELL FARMS.  The Company and its partner, Browning Oil Company, have
    completed drilling operations on a well at Lanell Farms, located in Gaines
    County, West Texas, which targeted the Devonian and Wolfcamp formations.
    With respect to the Wolfcamp formation, the well has been tested at rates
    greater than 200 Bbls/d. Production equipment is currently being installed
    and initial sales anticipated to occur in January 1997. The Company and its
    partner concluded that the Devonian formation will not produce commercial
    quantities of hydrocarbons. A second well, targeting the Wolfcamp formation,
    is scheduled to be spud in the first quarter 1997. The 2,000-acre project
    area is covered by a 3-D seismic survey in which the Company participated.
    The Company owns a 6% working interest in the first well and a 10% working
    interest in the second well to be drilled.
 
SIGNIFICANT BUSINESS RELATIONSHIPS
 
    As of December 15, 1996 the Company's current portfolio included 12 active
operator partners. Such partners are identified below:
 
<TABLE>
<CAPTION>
Alta Mesa Resources, Inc.             Esenjay Petroleum Corporation
<S>                                   <C>
Ameritex Ventures, Ltd.               Harrison Interests, Ltd.
Bellwether Exploration Company        Plains Resources, Inc.
Browning Oil Company                  PrimeEnergy Management Corporation
Cox & Perkins Exploration, Inc.       Santa Fe Energy Resources, Inc.
EnerVest Management Co.               Texoil Inc.
</TABLE>
 
                                       39
<PAGE>
    In February 1996, the Company formed a joint venture and strategic alliance
with Plains, the Company's partner in the Sunniland trend, pursuant to which the
companies agreed to jointly pursue exploitation and exploration opportunities.
Pursuant to the joint venture, the Company acquired a working interest of up to
8% in the Sunniland trend exploration project and an initial working interest of
approximately 7% in the Four Isle Dome project. In addition to their joint
venture, the Company and Plains have entered into a strategic alliance which has
an initial term of five years. Under the terms of the alliance, the Company has
the right to participate in exploitation or exploration projects where 3-D
seismic is applicable (i) for up to 15% of Plains' interest in the Illinois
Basin, located in southern Illinois, and in the Los Angeles Basin, located in
Los Angeles County, California, and (ii) for up to 20% of Plains' interest in
any additional properties Plains might acquire.
 
    The Company also has a strategic alliance with PrimeEnergy Management
Corporation, a subsidiary of PrimeEnergy Corporation, covering an area of mutual
interest in the Texas Gulf Coast trend and a contractual relationship on
projects with Esenjay Petroleum Corporation, a privately held corporation, in
the Texas Gulf Coast trend and the Mississippi/Alabama trend which, if
successful, could lead to a broader geographic alliance. See "--Significant
Projects and Properties." The Company believes that these types of joint
ventures and alliances involving long-term partner relationships enhance the
flow of opportunities presented to the Company and reduce the risk involved in
determining the quality of the partner and the relationship. As part of its
strategy, the Company attempts to convert successful relationships on individual
projects with quality partners into long-term strategic alliances.
 
    In addition to its relationship with certain operator partners, the Company
maintains an agreement with Landmark Graphics pursuant to which the Company has
acquired a license to use certain software manufactured by Landmark Graphics.
The Company also maintains informal agreements with Landmark Graphics which
entitle the Company's employees to participate in Landmark Graphics' medical
insurance plan, life insurance plans and 401(k) plan. The Company currently
anticipates that its informal agreements with Landmark Graphics will remain in
place until at least December 31, 1997. See "Certain Transactions--Agreements
with Landmark Graphics."
 
3-D IMAGING TECHNOLOGY
 
    The Company's oil and gas finding capabilities are dependent upon the
effective application of 3-D imaging technologies. Although the initial
application of 3-D imaging technology began in the late 1960's, its cost through
the 1970s justified use only in deep offshore applications and other
environments with substantial drilling costs and risk. By the mid-to-late 1980's
3-D imaging was a principal tool used in exploration activities in both the
North Sea and the Gulf of Mexico. Advances in technology during the 1980's made
the use of 3-D imaging more cost advantageous and more readily available for use
onshore.
 
    In general, 3-D imaging technology provides an "image" of the subsurface
geology by collecting seismic data along multiple parallel lines and creating a
cube of information which is spatially sampled throughout. The data acquired by
use of 3-D imaging technology is of a significantly better quality and provides
significantly greater advantages than the data acquired by 2-D seismic
technology. The higher fidelity and resolution of 3-D data result in more
accurate images than are possible using 2-D seismic and other conventional
methods. The productive application of 3-D imaging technology requires the
skills of highly trained experts.
 
GEOLOGIC, GEOPHYSICAL AND ENGINEERING EXPERTISE
 
    The Company has assembled a group of talented and experienced geologists,
geophysicists and engineers that work in multidisciplinary teams to enable the
Company to exploit fully the advantages afforded by 3-D imaging technologies.
The Company currently has ten full-time experts who design and manage the
process of seismic data acquisition, processing, imaging and analysis and drill
site selection using computer systems and software owned or licensed by the
Company. Each of those geoscientists and
 
                                       40
<PAGE>
engineers has between five to 20 years of experience involving the utilization
of seismic data imaging and analysis, and they have collectively participated in
over 300 3-D seismic projects in diverse geologic trends throughout the world.
By assembling in-house technical expertise, the Company is able to manage fully
and effectively the imaging and analytical phase of the projects in which it
participates. The Company provides its technical expertise exclusively to those
projects in which it participates as a working interest partner. See
"Management--Geoscientists and Engineers."
 
    By assembling for each project a multidisciplinary team of Company and
project partner experts, led by one of the Company's geoscientists or engineers,
the Company is able to capitalize on the expertise and experience of its
partners' technical staff while retaining management and overall responsibility
for the imaging and analytical phase of the project. If a project requires
technical expertise not available from the Company's or project partners'
personnel, the Company's project manager will identify and recruit an industry
expert to join the project team. In addition to being responsible for finding
oil and gas quickly and economically, the Company's project managers are in
charge of scheduling, budgeting and timely reporting. To insure that all
responsibilities assigned to various team members are completed in a systematic
manner and that all variables arising in connection with the imaging and
analysis of a specific project are thoroughly reviewed and integrated into the
imaging and analysis procedures, all of the Company's project managers are
required to adhere to the Company's technical template for each project for
which they are responsible. Generally, the Company's project manager maintains
responsibility for the project throughout the project life, which typically
extends through drilling of the last exploratory well.
 
RESEARCH AND DEVELOPMENT
 
    The Company believes that it possesses a competitive advantage over other
oil and gas companies by utilizing the experience of its in-house scientific
experts to continually develop innovative techniques and tools to optimize the
Company's utilization of 3-D imaging technologies. The Company's ongoing
research and development and its continuous accumulation of knowledge have
resulted in technical improvements and innovations that the Company believes
provide it with significant competitive advantages. Application of the 3DXPRESS
process, AVO, inversion and geostatistics to the process of reservoir
characterization and innovative utilization of technologies including digital
orthomaps and GPS locators are examples of such improvements which the Company
believes enable it to acquire higher quality seismic data than that which may be
acquired without effective utilization of such technologies and techniques. The
Company believes such higher quality data enable it to locate hydrocarbon
reserves more accurately thereby creating for it and its project partners a
significant competitive advantage. The Company enhances its ongoing research
program by forging strategic alliances with select suppliers of hardware and
software which have demonstrated foresight in the science of earth imaging. The
Company believes that its strategy of applied research and development will
allow it to remain at the forefront of oil and gas exploration technology.
 
    The Company has been able to adapt and refine concurrent imaging methods to
create the Company's 3DXPRESS process through the effective application of its
applied research and development strategy. In its first commercial application
of the 3DXPRESS process, the Company commenced and completed a project's imaging
and analysis phase in a four week period. Thereafter, the project operator
successfully drilled and completed four of the five resulting wells in a complex
geologic setting relying upon the Company's drill site and target depth
recommendations.
 
    Other innovations and improvements to the imaging process resulting from the
Company's ongoing research include the use of digital orthomaps for survey
planning and control, the use of GPS locators on seismic vibrators for
positioning control, application of AVO, inversion and geostatistics to the
process of reservoir characterization and the application of interactive
migration velocity analysis and depth migration to achieve superior image
reconstruction. Many of these innovations and improvements are the result of
strategic alignments with pioneering technology suppliers such as GPS
Technologies, Inc., Hampton-Russell Software, Inc., Landmark Graphics and
Paradigm Geophysical, Inc.
 
                                       41
<PAGE>
OIL AND GAS RESERVES
 
    All of the Company's proved reserves described below were located onshore in
West Texas and onshore and near-shore in the Louisiana and Texas Gulf Coast
region. All of the Company's proved reserves reflected in the table were proved
developed reserves. The Company's estimated total proved reserves of oil and
natural gas as of December 31, 1993, 1994 and 1995, and September 30, 1996,
based upon estimates prepared by the Company, were as set forth in the following
table:
 
<TABLE>
<CAPTION>
                                                                                     AT DECEMBER 31,
                                                                            ---------------------------------  AT SEPTEMBER
                                                                               1993        1994       1995       30, 1996
                                                                               -----     ---------  ---------  -------------
<S>                                                                         <C>          <C>        <C>        <C>
Estimated Net Proved Reserves Data:
  Gas (MMcf)..............................................................          20       1,237        443        2,169(1)
  Oil and condensate (MBbl)...............................................           4          40         41           31(1)
  Total equivalent (MMcfe)................................................          44       1,477        689        2,355
Pre-tax present value of proved reserves discounted at 10%(2).............   $      60   $   1,606  $     771    $   2,775
Standardized Measure of Discounted Future Net Cash Flows (in
  thousands)(2)(3)........................................................   $      60   $   1,606  $     771    $   2,775(1)
</TABLE>
 
- ------------------------
 
(1) Estimates of the Company's net proved gas and oil and condensate reserves
    and related revenue estimates as of September 30, 1996 were prepared by the
    Company and 2,146 MMcf and 27.3 MBbls of such gas and oil and condensate
    volumes, respectively, and $2,723,338 of pre-tax present values, have been
    the subject of a reserve report (the "Ryder Scott Reserve Report") prepared
    by Ryder Scott Company ("Ryder Scott"). A summary report prepared by Ryder
    Scott is included as Appendix A hereto. The other oil and gas reserve
    volumes and values at September 30, 1996 relate to royalty interests in
    other wells which were engineered solely by the Company's personnel.
 
(2) Because the Company has substantial net operating loss carryforwards, the
    amounts reflected are the same before taxes and after projected income
    taxes.
 
(3) In accordance with requirements of the Securities and Exchange Commission,
    represents the present value of estimated future net revenues after income
    taxes discounted at 10%.
 
    In addition to the discussion below, reference is made to the Financial
Statements including the Supplemental Oil and Gas Information (unaudited)
included in the notes thereto included elsewhere herein. Such discussion also
contains information with respect to the Company's reserves at December 31,
1993, 1994, 1995 and at September 30, 1996.
 
    The Company has not included estimates of total proved reserves, comparable
to those disclosed herein, in any reports filed with federal authorities or
agencies other than the Commission.
 
    At December 31, 1993, 1994 and 1995 and September 30, 1996, the Company held
interests in the following productive wells:
<TABLE>
<CAPTION>
                                                                AT DECEMBER 31,
                                  ----------------------------------------------------------------------------      AT
                                                                                                                 SEPTEMBER
                                            1993                      1994                      1995             30, 1996
                                  ------------------------  ------------------------  ------------------------  -----------
                                   GROSS(1)      NET(2)      GROSS(1)      NET(2)      GROSS(1)      NET(2)      GROSS(1)
                                  -----------  -----------  -----------  -----------  -----------  -----------  -----------
<S>                               <C>          <C>          <C>          <C>          <C>          <C>          <C>
Oil Wells.......................           3         0.03            6         0.06            7         0.16            8
Gas Wells.......................      --           --                4         0.56            5         0.74           10
 
<CAPTION>
 
                                    NET(2)
                                  -----------
<S>                               <C>
Oil Wells.......................        0.25
Gas Wells.......................        1.50
</TABLE>
 
- ------------------------
 
(1) The number of gross wells equals the total number of wells in which the
    Company owns a working interest.
 
                                       42
<PAGE>
(2) The number of net wells equals the sum of the Company's fractional working
    interests owned in gross wells.
 
    In general, estimates of economically recoverable oil and gas reserves and
of the future net revenues therefrom are based upon a number of variable factors
and assumptions, such as historical production from the subject properties, the
assumed effects of regulation by governmental agencies and assumptions
concerning future oil and natural gas prices and future operating costs, all of
which may vary considerably from actual results. All such estimates are to some
degree speculative and classifications of reserves are only attempts to define
the degree of speculation involved. For these reasons, estimates of the
economically recoverable oil and gas reserves attributable to any particular
group of properties, classifications of such reserves based on risk of recovery
and estimates of the future net revenues expected therefrom, prepared by
different engineers or by the same engineers at different times, may vary
substantially. Therefore, the actual production, revenues, severance and excise
taxes, development and operating expenditures with respect to the Company's
reserves will likely vary from such estimates, and such variances could be
material.
 
    The Company's producing wells have been producing for only a short period of
time. Accordingly, estimates of future production based on this limited history
are subject to various uncertainties with regard to the rate at which current
production will decline. Estimates with respect to proved reserves that may be
developed and produced in the future are often based upon volumetric
calculations and upon analogy to similar types of reserves rather than actual
production history. Estimates based on these methods are generally less reliable
than those based on actual production history, and subsequent evaluation of the
same reserves, based upon production history, will result in variations, which
may be substantial, in the estimated reserves. See "Risk Factors--Limited
Operating History and Significant Historical Operating Losses."
 
    In accordance with applicable requirements of the Commission, the estimated
discounted future net revenues from estimated proved reserves are based on
prices and costs as of the date of the estimate unless such prices or costs are
contractually determined at such date. Actual future prices and costs may be
materially higher or lower. Actual future net revenues also will be affected by
factors such as actual production, supply and demand for oil and gas,
curtailments or increases in consumption by natural gas purchasers, changes in
governmental regulations or taxation and the impact of inflation on costs. See
"Risk Factors--Volatility of Oil and Gas Prices."
 
                                       43
<PAGE>
OIL AND GAS DRILLING ACTIVITIES
 
    The following table sets forth the gross and net number of productive, dry
and total exploratory and development wells that the Company drilled in each of
1993, 1994, 1995 and during the first nine months of 1996.
<TABLE>
<CAPTION>
                                                                            GROSS WELLS                      NET WELLS
                                                               -------------------------------------  ------------------------
                                                                PRODUCTIVE       DRY        TOTAL      PRODUCTIVE       DRY
                                                               -------------     ---        -----     -------------  ---------
<S>                                                            <C>            <C>        <C>          <C>            <C>
EXPLORATORY WELLS(1)
Year ended December 31, 1993.................................            3            0           3          0.03       --
Year ended December 31, 1994.................................            7            5          12          0.59         0.70
Year ended December 31, 1995.................................            2            0           2          0.28       --
Nine months ended September 30, 1996.........................            6            6          12          0.69         0.67
 
DEVELOPMENT WELLS
Year ended December 31, 1993.................................       --           --          --            --           --
Year ended December 31, 1994.................................       --           --          --            --           --
Year ended December 31, 1995.................................       --           --          --            --           --
Nine months ended September 30, 1996.........................            2       --               2          0.40       --
 
<CAPTION>
 
                                                                 TOTAL
                                                               ---------
<S>                                                            <C>
EXPLORATORY WELLS(1)
Year ended December 31, 1993.................................       0.03
Year ended December 31, 1994.................................       1.29
Year ended December 31, 1995.................................       0.28
Nine months ended September 30, 1996.........................       1.36
DEVELOPMENT WELLS
Year ended December 31, 1993.................................     --
Year ended December 31, 1994.................................     --
Year ended December 31, 1995.................................     --
Nine months ended September 30, 1996.........................       0.40
</TABLE>
 
- ------------------------
 
(1) As of the date of this Prospectus, the Company was participating in two
    gross and 0.26 net exploratory wells.
 
PRODUCTION
 
    The following table summarizes the net volumes of oil and gas produced and
sold, and the average prices received with respect to such sales, from all
properties in which the Company held an interest during the three years ended
December 31, 1995 and for the nine months ended September 30, 1996.
 
<TABLE>
<CAPTION>
                                                                    GAS                                OIL
                                                      --------------------------------  ----------------------------------
                                                      NET PRODUCTION    AVERAGE SALES     NET PRODUCTION     AVERAGE SALES
                                                          (MMCF)          PRICE/MCF           (MMCF)           PRICE/BBL
                                                      ---------------  ---------------  -------------------  -------------
<S>                                                   <C>              <C>              <C>                  <C>
Year ended December 31, 1993........................        --            $  --                 --             $  --
Year ended December 31, 1994........................         105.1             1.93                6.1             16.58
Year ended December 31, 1995........................          97.1             1.59                6.7             17.89
Nine months ended September 30, 1996................         117.8             2.41                6.5             19.17
</TABLE>
 
    Average oil and gas operating expenses per Mcfe were $0.10, $0.44 and $0.18
for the years ended December 31, 1994 and 1995 and the nine month period ended
September 30, 1996, respectively. With the addition of severance and ad valorem
taxes, the total average oil and gas operating expenses per Mcfe were $0.24,
$0.57 and $0.33 for the years ended December 31, 1994 and 1995 and nine months
ended September 30, 1996, respectively.
 
ACREAGE
 
    The following table sets forth the developed and undeveloped oil and gas
acreage in which the Company held an interest as of September 30, 1996.
Undeveloped acreage is considered to be those lease
 
                                       44
<PAGE>
acres on which wells have not been drilled or completed to a point that would
permit the production of commercial quantities of oil and gas, regardless of
whether or not such acreage contains proved reserves.
 
<TABLE>
<CAPTION>
                                                                                    DEVELOPED            UNDEVELOPED
                                                                               --------------------  --------------------
                                                                                 GROSS       NET       GROSS       NET
                                                                               ---------  ---------  ---------  ---------
<S>                                                                            <C>        <C>        <C>        <C>
Alabama......................................................................     --         --         --         --
Florida......................................................................     --         --          5,000        400
Texas........................................................................      2,976        462     46,219      6,381
Louisiana....................................................................      2,880        144      8,900        499
Mississippi..................................................................     --         --          3,280        492
                                                                               ---------  ---------  ---------  ---------
Total........................................................................      5,856        606     63,399      7,772
                                                                               ---------  ---------  ---------  ---------
                                                                               ---------  ---------  ---------  ---------
</TABLE>
 
    In addition to the above acreage, as of the date of this Prospectus, the
Company has options or farm-ins to acquire leases on 217,420 gross (27,523 net)
acres of undeveloped land located in Alabama, Florida, Louisiana, Mississippi
and Texas.
 
COMPETITION
 
    Competition in the oil and gas industry is intense, particularly with
respect to the acquisition of acreage and capital. The Company's competitors in
the provision of seismic imaging, analytical and other related services include
numerous major and independent oil and gas companies, smaller, technology-driven
service companies, individual proprietors, drilling and income programs and
partnerships. Many of the Company's competitors possess and employ financial and
personnel resources substantially in excess of those available to the Company
and may, therefore, be able to define, evaluate, bid for and participate in a
greater number of oil and gas properties than the Company. The Company believes
that technology, experience and reliability are the primary basis of competition
in the industry, as oil and gas exploration companies demand higher quality
seismic data delivered and analyzed in increasingly shorter time frames and
greater assurances that the interests of such company are respected and
advanced. Although the Company believes that it competes effectively in each of
these areas, there can be no assurance that the Company's ability to attract and
invest in high quality projects will not be adversely affected if its current
competitors or new market entrants introduce new services with better quality
technology than those offered by the Company. See "Risk Factors--Competition."
 
REGULATION
 
    The Company's operations are subject to numerous federal, state and local
laws and regulations governing the discharge of materials into the environment
or otherwise relating to environmental protection. Public interest in the
protection of the environment has increased dramatically in recent years.
Offshore drilling in certain areas has been opposed by environmental groups and,
in certain areas, has been restricted. The Company believes that the trend of
more expansive and stricter environmental legislation and regulations will
continue. To the extent laws are enacted or other governmental action is taken
that prohibit or restrict onshore and offshore drilling or impose environmental
protection requirements that result in increased costs to the oil and gas
industry in general, the business and prospects of the Company could be
adversely affected.
 
    The Oil Pollution Act of 1990 (the "OPA") and regulations thereunder impose
a variety of requirements on "responsible parties" related to the prevention of
oil spills and liability for damages resulting from such spills in United States
waters. A "responsible party" includes the owner or operator of a facility or
vessel, or the lessee or permittee of the area in which an offshore facility is
located. The OPA assigns liability to each responsible party for oil removal
costs and a variety of public and private damages including natural resource
damages. While liability limits apply in some circumstances, a party cannot take
 
                                       45
<PAGE>
advantage of liability limits if the spill was caused by gross negligence or
willful misconduct or resulted from violation of a federal safety, construction
or operating regulation. If the party fails to report a spill or to cooperate
fully in the cleanup, liability limits likewise do not apply. Few defenses exist
to the liability imposed by the OPA.
 
    Under the OPA, the Minerals Management Service ("MMS") has the authority to
promulgate regulations requiring financial assurance from owners and operators
of "offshore facilities" to cover potential environmental cleanup and
restoration costs. Although there has been uncertainty about the scope and
applicability of these requirements, Congress recently adopted legislation that
has been signed by the President that excludes certain inland facilities with a
worst-case oil spill risk of 1,000 barrels or less from the financial assurance
requirements. Under this new legislation, the amount of financial responsibility
that must be demonstrated for an offshore facility was reduced to $35.0 million
if the facility is located seaward of the seaward boundary of a State, or $10.0
million if located landward of the boundary. These limitations can be adjusted
upward should MMS believe there are additional risks. In projects in which the
Company has a participating working interest, the operator partner is
responsible for all demonstrations of financial responsibility including the
posting of any indemnity bonds which are required by applicable governmental
regulations. The expenses incurred in the operator partner's demonstration of
financial responsibility are expenses which are allocated to each project
partner based on the respective partner's working interest.
 
    The OPA also imposes other requirements, such as the preparation of an oil
spill contingency plan. The Company has such a plan in place. Failure to comply
with ongoing requirements or inadequate cooperation during a spill event may
subject a responsible party to civil or criminal enforcement actions.
 
    To complement the OPA, the State of Texas enacted the Oil Spill Prevention
and Response Act (OSPRA). The Texas General Land Office (GLO) is the lead agency
for carrying out OSPRA and to that end the GLO has promulgated regulations
affecting anyone who owns or operates a vessel or facility that stores or
transfers oil in areas where a spill could reach Texas coastal waters.
 
    In addition, the Outer Continental Shelf Lands Act ("OCSLA") authorizes
regulations relating to safety and environmental protection applicable to
lessees and permittees operating on the Outer Continental Shelf (the "OCS").
Specific design and operational standards may apply to OCS vessels, rigs,
platforms, vehicles and structures. Violations of lease conditions or
regulations issued pursuant to the OCSLA can result in substantial civil and
criminal penalties, as well as potential court injunctions curtailing operations
and the cancellation of leases. Such enforcement liabilities can result from
either governmental or private prosecution.
 
    The Comprehensive Environmental Response, Compensation and Liability Act
("CERCLA"), also known as the "Superfund" law, imposes liability, without regard
to fault or the legality of the original conduct, on certain classes of persons
that are considered to have contributed to the release of a "hazardous
substance" into the environment. These persons include the owner or operator of
the disposal site or sites where the release occurred and companies that
disposed or arranged for the disposal of the hazardous substances found at the
site. Persons who are or were responsible for releases of hazardous substances
under CERCLA may be subject to joint and several liability for the costs of
cleaning up the hazardous substances that have been released into the
environment and for damages to natural resources. Additionally, it is not
uncommon for neighboring landowners and other third parties to file claims for
personal injury and property damage allegedly caused by the hazardous substances
released into the environment. Further, certain oilfield wastes are subject to
the Resource Conservation & Reservation Act ("RCRA") with respect to the
regulation of hazardous wastes. The RCRA regulates the generation,
transportation and disposal of hazardous wastes.
 
    The Texas Railroad Commission has issued rules for management of certain
types of hazardous waste generated in the oilfield, however, until delegation of
the RCRA program to the Railroad Commission, hazardous wastes generated in the
oilfield are regulated by the Texas Natural Resources Conservation
 
                                       46
<PAGE>
Commission. The Texas Railroad Commission regulates pollution of groundwater and
surface water resulting from exploration, production and development of oil and
natural gas resources.
 
    The Clean Water Act (CWA) and regulations promulgated thereunder prohibit
the discharge of pollutants into waters of the United States without a permit
pursuant to the National Pollutant Discharge Elimination System (NPDES)
provisions. The CWA also requires reporting of oil spills to the National
Response Center. The Environmental Protection Agency has issued general NPDES
permits for oil and gas platforms in the Gulf of Mexico which permits impose
limits on discharges of such things as oil, grease, produced water and drilling
fluids. Onshore platforms may also be subject to the requirement for NPDES
permits for both production discharges and for discharges of stormwater. In
Louisiana, the NPDES permit program has recently been delegated to the State of
Louisiana. In Texas, the NPDES permit program is administered by EPA. Failure to
obtain the proper permit may result in both civil and criminal penalties as well
as an order to cease discharges, which in effect is an order to shut down
production.
 
    Management believes that the Company is in substantial compliance with
current applicable environmental laws and regulations. Compliance with such laws
and regulations has not historically represented a significant expense for the
Company and management does not foresee the need for material expenditures to
ensure continued compliance with currently existing laws and regulations. Laws
and regulations in these areas are, however, subject to change and there can be
no assurance that future laws or regulations will not have a material adverse
effect on the Company. See "Risk Factors--Compliance with Governmental
Regulations."
 
OPERATING HAZARDS AND INSURANCE
 
    The oil and gas business involves a variety of operating risks, including
the risk of fire, explosions, blow-out, pipe failure, casing collapse,
abnormally pressured formations and environmental hazards such as oil spills,
gas leaks, ruptures and discharges of toxic gases, the occurrence of any of
which could result in substantial losses to the Company due to injury or loss of
life, severe damage to or destruction of property, natural resources and
equipment, pollution or other environmental damage, clean-up responsibilities,
regulatory investigation and penalties and suspension of operations. In addition
to the foregoing, offshore operations are subject to the additional hazards of
marine operations, such as capsizing, collision and adverse weather and sea
conditions.
 
    Through operator partners, the Company indirectly maintains insurance
against some, but not all, operating risks. The insurance maintained by project
operator partners generally does not cover claims relating to failure of title
to oil and gas leases, trespass during 3-D survey acquisition or surface damage
attributible to seismic operations, business interruption or protect against
loss of revenues due to well failure. There can be no assurance that any
insurance obtained by project operator partners covering claims related to
worker's compensation, comprehensive general liability for bodily injury and
property damage, comprehensive automobile liability and pollution, cleanup,
underground blowout and evacuation will be adequate to cover any losses or
liabilities which may be incurred within projects in which the Company
participates. The Company is an additional named insured on the insurance
policies procured and maintained by operator partners. The Company cannot
predict the continued availability of such insurance or the availability of
insurance at premium levels that justify its purchase. If any project operator
partner were unable to procure insurance at an acceptable cost with respect to
each of the projects in which the Company participates, the occurrence of
significant adverse events not fully insured or indemnified against could
materially and adversely affect the Company's financial condition and
operations. See "Risk Factors--Operating Hazards."
 
                                       47
<PAGE>
EMPLOYEES AND INDEPENDENT CONSULTANTS
 
    At December 15, 1996, the Company had 14 full-time employees including ten
geoscientists and engineers and one person, the President and Chief Executive
Officer, engaged principally in the management of the Company. The Company
believes that its relationship with its employees is good. None of the Company's
employees is covered by a collective bargaining agreement. At December 15, 1996,
the Company had arrangements with eight individuals to provide, from time to
time, various consulting and professional services. The agreements with these
consultants provide for the payment of fees and expenses for services rendered.
The Company has commenced and expects to continue a program to hire recent
college graduates and advanced degree holders. See "Management."
 
LEGAL PROCEEDINGS
 
    Since its organization through the date of this Prospectus, the Company has
not been involved in any legal proceedings. There can be no assurance, however,
that the Company will not in the future be involved in litigation incidental to
the conduct of its business.
 
                                       48
<PAGE>
                                   MANAGEMENT
 
DIRECTORS AND EXECUTIVE OFFICERS
 
    The following table sets forth certain information with respect to the
directors and executive officers of the Company.
 
<TABLE>
<CAPTION>
                NAME                      AGE                                POSITION
- ------------------------------------  -----------  ------------------------------------------------------------
<S>                                   <C>          <C>
Jon W. Bayless (1)..................          56   Director, Chairman of the Board
C. Eugene Ennis.....................          52   President and Chief Executive Officer; Director
Peter M. Duncan.....................          44   Vice President of Technology; Treasurer
Douglas C. Nester...................          39   Vice President of Exploration; Secretary
Robert J. Bacon, Jr.................          42   Vice President of Joint Ventures
Joseph Schuchardt III...............          44   Vice President of Business Development
Robert H. Chaney (1)................          37   Director
Charles E. Edwards (2)..............          71   Consultant; Director
Douglas C. Williamson (2)...........          45   Director
</TABLE>
 
- ------------------------
 
(1) Member of the Company's Compensation Committee.
 
(2) Member of the Company's Audit Committee.
 
    Upon completion of the Offering, the term of office of the members of the
Board of Directors will be staggered into three classes. The initial term of
each of Class I, Class II and Class III will expire at the first, second and
third annual meetings, respectively, of the Board of Directors which is held
after the completion of this Offering. Each class will thereafter have a term of
three years.
 
    JON W. BAYLESS. Mr. Bayless has been Chairman of the Board of the Company
since October 1996 and a Director since November 1993. Since 1983, Mr. Bayless
has been a general partner of Sevin Rosen Funds, a venture capital investment
firm. Mr. Bayless is also the controlling stockholder and sole director of Jon
W. Bayless, Inc., the general partner of Atlantic Partners L.P., which is the
general partner of Citi Growth Fund L.P., a venture capital investment firm, and
serves as a director of a number of privately held companies. Mr. Bayless is
also Chairman of the Board of Directors of Shared Resource Exchange, Inc. Shared
Resource Exchange, Inc. filed for reorganization under Chapter 11 of the Federal
Bankruptcy Code in August 1996. A plan under Chapter 11 has been approved.
 
    C. EUGENE ENNIS. Mr. Ennis, who co-founded the Company with Peter M. Duncan
and Douglas C. Nester, has served as the Company's President and Chief Executive
Officer and as a Director since the Company's inception in December 1992. From
September 1984 to December 1992, Mr. Ennis was President and Chief Executive
Officer of Landmark Graphics, a provider of interdisciplinary interpretation
tools for the petroleum industry. Mr. Ennis holds a Bachelor of Science in
electrical engineering from the University of Houston and began his career in
1969 as a design engineer in the Geophysical Products Division of Texas
Instruments where he was employed until 1983.
 
    PETER M. DUNCAN. Dr. Duncan, a co-founder of the Company, has served as the
Company's Vice President of Technology and Treasurer since the Company's
inception. Prior to joining the Company, Dr. Duncan was employed by Landmark
Concurrent Solutions Inc., an affiliate of Landmark Graphics, that merged with
ExploiTech, as Vice President from July 1991 until December 1992. Dr. Duncan was
a founder in 1987 of ExploiTech, a company specializing in integrated
multi-disciplinary reservoir description studies for exploration and
exploitation that merged with Landmark Graphics in 1989. From 1986 to 1987, Dr.
Duncan served as Vice President of Marine Operations and Chief Geophysicist of
North America for Digicon Inc., a major geophysical contractor. From 1984 to
1986, Dr. Duncan was employed as Chief Geophysicist of Pulsonic Geophysical of
Calgary Inc., a former subsidiary of Digicon Inc. From 1978 to 1984, Dr. Duncan
held various positions with Shell Canada Resources Inc. ("Shell"), including
Party Chief
 
                                       49
<PAGE>
for Shell's offshore seismic programs. Dr. Duncan holds a Ph.D in geophysics
from the University of Toronto.
 
    DOUGLAS C. NESTER. Mr. Nester, a co-founder of the Company, has served as
the Company's Vice President of Exploration and Secretary since the Company's
inception. Prior to joining the Company, Mr. Nester was employed by Landmark
Concurrent Solutions Inc., an affiliate of Landmark Graphics that merged with
ExploiTech, as Director of Technology from June 1988 to December 1992. From 1981
to 1988, Mr. Nester was employed in various geophysical positions by Pennzoil
Corp., and held the position of Geophysical Specialist at the time of his
departure. Mr. Nester began his career as an engineering geologist for Bechtel
Corporation. Mr. Nester holds a Bachelor of Science in Geology from Indiana
University of Pennsylvania and a Masters in Business Administration in Finance
from the University of St. Thomas.
 
    ROBERT J. BACON, JR. Mr. Bacon has been Vice President of Joint Ventures
since September 1995. Prior to joining the Company, Mr. Bacon was Manager of
Business Development for Scientific Software-Intercomp, Inc., a software
company, from May 1994 to June 1995 and served as Vice President of Sales and
Marketing for JetFax Inc, a manufacturer of facsimile machines and facsimile
peripherals, from September 1990 to May 1994. From 1988 to 1990, Mr. Bacon was
employed by ExploiTech as the Director of Marketing for consulting services.
From 1985 to 1987, Mr. Bacon held positions in key account management at
Landmark Graphics. Mr. Bacon is a founder and currently serves on the Board of
Directors of Innovative Transducers Inc., a privately held designer and
manufacturer of solid towed hydrophonic arrays for the military and geophysical
marine markets. Mr. Bacon holds a Bachelor of Science in Advertising from the
University of Texas.
 
    JOSEPH SCHUCHARDT III. Mr. Schuchardt has served as the Company's Vice
President of Business Development since November 1993. Prior to his employment
with the Company, Mr. Schuchardt served as Vice President of Land for Great
Western Resources Inc. from April 1992 to November 1993. Mr. Schuchardt also
served as Vice President of Land for Paramount Petroleum Company from 1991 to
1992. Mr. Schuchardt was employed as Land Manager of Horizon Exploration Company
from 1980 to 1991 and has held positions with Texas Oil & Gas Corporation,
Coastal States Oil and Gas Corporation and Texaco Inc. Mr. Schuchardt holds a
B.B.A. in Management from the University of Texas.
 
    ROBERT H. CHANEY. Mr. Chaney has served as a Director of the Company since
November 1993. Mr. Chaney is Chairman and Chief Executive Officer of R. Chaney &
Co., Inc., an investment firm specializing in equity investments in emerging
energy technology companies. Mr. Chaney was a co-founder of Paramount Petroleum
Company, an independent oil and gas company, and served as its President and
Chief Executive Officer from 1986 to July 1993.
 
    CHARLES E. EDWARDS. Mr. Edwards has served as a Director of the Company
since August 1995. Since August 1985 to present, Mr. Edwards has acted as a
consultant in petroleum technologies. Prior to August 1985, Mr. Edwards was
employed by Chevron Corp. for a period in excess of 37 years and most recently
served as Chief Geophysicist with responsibility for global exploration
activities. Mr. Edwards has also served as a director for Digicon Inc. and
Landmark Graphics.
 
    DOUGLAS C. WILLIAMSON. Mr. Williamson has served as a Director to the
Company since July 1995. Mr. Williamson is a Managing Director in the Venture
Capital Group in the Dallas, Texas office of NationsBanc Capital Corporation.
 
                                       50
<PAGE>
GEOSCIENTISTS AND ENGINEERS
 
    In addition to Dr. Duncan and Mr. Nester, the Company has assembled a group
of talented and experienced geologists, geophysicists and engineers to enable it
to exploit fully the advantages afforded by 3-D imaging technology. Information
with respect to those experts is set forth below.
 
    HERBERT R. ROHLOFF.  Mr. Rohloff has served as a Senior Reservoir Engineer
since joining the Company in January 1995. He is a registered professional
engineer in the State of Texas. Prior to joining the Company, Mr. Rohloff was
employed by Amoco Production Company from 1979 to 1993 in various engineering,
economic and supervisory positions beginning in 1979 and served most recently as
Project Manager--Production New Ventures. Mr. Rohloff holds a Bachelor of
Science in Chemical Engineering from Texas A&M University.
 
    DOUGLAS W. BECKMAN.  Mr. Beckman has served as a Project Manager since
joining the Company in September 1994. Mr. Beckman has over 12 years of
experience in the oil and gas industry. Prior to joining the Company, Mr.
Beckman was employed by Exxon Corp. from May 1982 to August 1994, and served
most recently as a seismic applications specialist. Mr. Beckman holds a Bachelor
of Arts in Geology from Wittenberg University.
 
    ERIC B. GARDNER.  Mr. Gardner has served as Project Manager since joining
the Company in September 1994. Mr. Gardner has over ten years of industry
experience and has worked in many geoscience areas, including production,
exploration, seismic technology, and research. Mr. Gardner began his career with
Amoco Production Company in 1985 as a technical geophysicist and served most
recently as a staff geophysicist. Mr. Gardner holds a Bachelor of Science in
Engineering Physics from Colorado School of Mines.
 
    JEFFREY K. OWENS.  Mr. Owens has served as a Project Manager since joining
the Company in August 1994. Prior to joining the Company, Mr. Owens was employed
by Amoco Production Company where he began his career in 1984 as a production
and reservoir engineer and served most recently as a staff geophysicist. Mr.
Owens holds a Bachelor of Science in Petroleum Engineering from Mississippi
State University.
 
    RICHMOND MILLER.  Mr. Miller has served as a Senior Geophysicist since
joining the Company in September 1996. Prior to joining the Company, Mr. Miller
held various positions with Digicon Geophysical Corp. beginning in 1987 and
served most recently as Marine Acquisition Manager. Mr. Miller holds a Bachelor
of Science in Geology from Stephen F. Austin State University.
 
    MICHAEL A. SAUNDERS.  Mr. Saunders has served as a Senior Geophysicist since
joining the Company in December 1994. Mr. Saunders began his career with
Pulsonic Geophysical of Calgary Inc. as a Processing Geophysicist. From 1987 to
1994, Mr. Saunders was employed by Digicon Geophysical Corp., and served most
recently as Manager of Marine Technology. Mr. Saunders has a Bachelor of Science
in Geophysics from the University of Alberta, Edmonton, Alberta.
 
    CAROL ANNE ESTES.  Ms. Estes has served as an Explorationist since joining
the Company in June 1996. Prior to joining the Company, Ms. Estes was employed
as a Senior Geophysicist for Exxon Exploration Company from April 1994 to June
1996. Ms. Estes holds a Bachelor of Science in Geophysics from Texas A&M
University and a Master of Science in Geophysics from Stanford University.
 
    BRENDA HAGAN.  Ms. Hagan has served as a Senior Exploration Technologist
since joining the Company in December 1993. Ms. Hagan began her career with
Houston Oil & Minerals Corp. in 1977. From 1989 to November 1993 she was
employed as a geological technician at British Gas Exploration and Production.
 
                                       51
<PAGE>
OTHER EMPLOYEES
 
    GAYLE ANDERSON.  Ms. Anderson has served as Office Manager of the Company
since April 1996. Prior to joining the Company, Ms. Anderson held positions in
various areas, including accounts payable and commercial loans. Ms. Anderson
also served as office manager of R.J. Power & Associates from September 1995 to
April 1996. From June 1989 to September 1995, Ms. Anderson managed Andco, Inc.,
a business which she co-founded, serving as Comptroller, Human Relations and
Payroll Officer.
 
CONSULTANTS
 
    HARDIE W. MORGAN.  Mr. Morgan is a Certified Public Accountant and has
served as a consultant to the Company since January 1993. Mr. Morgan has been
self-employed since January 1992 as a consultant providing business and
financial services to a number of public and private companies. From April 1985
until December 1991, Mr. Morgan served as Chief Financial Officer of Landmark
Graphics.
 
    JOHN M. JAMES.  Mr. James is a Certified Public Accountant and has served as
a consultant to the Company since January 1993. Mr. James founded his own
accounting firm in 1990. Prior to that time, Mr. James was a partner at Ernst &
Young LLP.
 
COMMITTEES OF THE BOARD OF DIRECTORS
 
    The Board of Directors has established two committees, a Compensation
Committee and an Audit Committee. The Compensation Committee currently consists
of Messrs. Bayless and Chaney and the Audit Committee currently consists of
Messrs. Edwards and Williamson. The Compensation Committee reviews general
policy matters relating to compensation and benefits of officers and employees
of the Company and administers the Stock Option Plan. The Audit Committee,
established in October 1996, is responsible for recommending to the Board of
Directors the annual engagement of a firm of independent accountants and for
reviewing with the independent accountants the scope and results of audits, the
internal accounting controls of the Company and audit practices and professional
services rendered to the Company by the independent accountants.
 
COMPENSATION OF DIRECTORS
 
    Following the completion of the Offering, independent Directors will receive
a fee in the amount of $750 for every board meeting attended in person or by
telephone and a fee of $500 for each committee meeting held separately attended
in person or by telephone. All Directors who are not employees of the Company,
will be reimbursed for out-of-pocket expenses. Under the Stock Option Plan, the
Company may, from time to time, and in the discretion of the Board of Directors,
grant stock options to Directors.
 
EXECUTIVE COMPENSATION
 
    The following table sets forth information concerning compensation for
services in all capacities awarded to, earned by or paid to, the Company's Chief
Executive Officer and the Company's other most highly compensated executive
officers, whose aggregate cash and cash equivalent compensation exceeded
$100,000 (the "Named Executives"), with respect to the year ended December 31,
1995. The table also identifies the principal capacity in which each of the
Named Executives served the Company at the end of 1995. No other executive
officer of the Company received cash and cash equivalent compensation which
exceeded $100,000 in the aggregate.
 
                                       52
<PAGE>
                           SUMMARY COMPENSATION TABLE
 
<TABLE>
<CAPTION>
NAME AND PRINCIPAL POSITION                                                  YEAR     SALARY($)   BONUS($)
- -------------------------------------------------------------------------  ---------  ----------  ---------
<S>                                                                        <C>        <C>         <C>
C. Eugene Ennis
  President and Chief Executive Officer..................................       1995  $  150,000  $  --
 
Peter M. Duncan
  Vice President of Technology; Treasurer................................       1995     103,920     12,000
</TABLE>
 
STOCK OPTION GRANTS
 
    The following table sets forth certain information regarding options to
purchase Common Stock which the Company has granted since January 1, 1996.
 
<TABLE>
<CAPTION>
                                                                           NUMBER OF SHARES
                                                                            OF COMMON STOCK    EXERCISE
 DATE OF                                                                      UNDERLYING       PRICE PER
  GRANT    GRANTEE                                                            OPTIONS(1)         SHARE
- ---------  --------------------------------------------------------------  -----------------  -----------
<S>        <C>                                                             <C>                <C>
1/4/96     Independent Board Members.....................................          20,680      $    0.58
4/11/96    Employee......................................................           2,585           0.58
4/11/96    Consultant....................................................           5,170           0.58
6/7/96     Employee......................................................          18,095           0.58
7/11/96    Employee......................................................          25,850           0.58
8/2/96     Employee......................................................           7,755           0.58
10/4/96    Consultants...................................................          27,401           7.79
11/1/96    Consultant....................................................           5,170          11.20
                                                                                  -------
  Total options granted in 1996..........................................         112,706
                                                                                  -------
                                                                                  -------
</TABLE>
 
- ------------------------
 
(1) All options to purchase Common Stock were granted pursuant to the Stock
    Option Plan.
 
(2) The total number of options granted is net of cancelled options to purchase
    155,100 shares of Common Stock that were granted to an executive officer who
    both commenced and terminated his service to the Company during 1996.
 
OPTION EXERCISES AND YEAR-END VALUE TABLE
 
    The following table sets forth information regarding the exercise of stock
options during fiscal 1995 and the number and year-end value of unexercised
options held at December 31, 1995, by each of the Named Executives. No stock
options or stock appreciation rights were exercised by the Named Executives
during fiscal 1995.
 
                   AGGREGATE OPTION EXERCISES IN FISCAL 1995
                     AND FISCAL 1995 YEAR-END OPTION VALUES
 
<TABLE>
<CAPTION>
                                                               NUMBER OF SECURITIES        VALUE OF UNEXERCISED
                                                             UNDERLYING UNEXERCISABLE         "IN-THE-MONEY"
                                                                OPTIONS AT FISCAL           OPTIONS AT FISCAL
                                                                   YEAR-END (#)                YEAR-END($)
NAME                                                        EXERCISABLE/UNEXERCISABLE(1) EXERCISABLE/UNEXERCISABLE(2)
- ----------------------------------------------------------  --------------------------  --------------------------
<S>                                                         <C>                         <C>
C. Eugene Ennis...........................................           10,911/9,233              150,644/127,476
Peter M. Duncan...........................................           10,912/9,233              150,657/127,476
</TABLE>
 
- ------------------------
 
(1) The number of unexercised options held by each of the Named Executive
    Officers represents approximately 3% of the total options outstanding under
    the Stock Option Plan.
 
                                       53
<PAGE>
(2) Options are "in-the-money" if the fair market value of the underlying
    securities exceeds the exercise price of the options. Prior to the Offering,
    there was no public market for the Common Stock. Therefore, the amounts set
    forth represent the difference between $0.58 per share and the fair market
    value of the Common Stock issuable upon exercise of options at December 31,
    1995 (as determined using the initially estimated offering price for the
    Common Stock), multiplied by the applicable number of options. Based on the
    initial public offering price of $11.00 per share of Common Stock, the value
    of unexercised "in the money" options at December 31, 1995 would have been
    as follows: Mr. Ennis--$117,911/99,777 (exercised/unexercisable) and Dr.
    Duncan--$117,921/99,777 (exercisable/unexercisable).
 
CASH BONUS PLAN
 
    In 1996 the Company adopted the 1996 Incentive Compensation Plan (the "Bonus
Plan") which provides for the payment of annual cash bonuses, in an amount up to
40% of the participant's base salary, if certain pre-established Company-based
performance criteria are satisfied. All full-time employees of the Company are
eligible to participate in the Bonus Plan, with the exception of the Chief
Executive Officer. Bonuses are awarded if the Company achieves at least 80% of
its targeted performance criteria. The bonuses are then prorated accordingly.
The bonus of the Chief Executive Officer is separately determined in the
discretion of the Board of Directors.
 
STOCK OPTION PLAN
 
    In January 1994, the Company adopted the Stock Option Plan under which
"non-qualified" stock options ("NQSOs") to acquire shares of Common Stock may be
granted to directors of and consultants to the Company and "incentive" stock
options ("ISOs") to acquire shares of Common Stock may be granted to employees
and directors who are also employees of the Company.
 
    The Stock Option Plan provides for the issuance of up to a maximum of
1,504,937 shares of Common Stock and is administered by the Compensation
Committee. Under the Stock Option Plan, the option price of any ISO may not be
less than the fair market value of a share of Common Stock on the date on which
the option is granted. The option price of an NQSO may be less than the fair
market value on the date the NQSO is granted if the Compensation Committee so
determines, but may not in any event be less than 85% of such fair market value.
An ISO may not be granted to a "ten percent stockholder" (as such term is
defined in Section 422A of the Code) unless the exercise price is at least 110%
of the fair market value of the Common Stock at the time of grant and the option
must be exercised within five years. Each option granted pursuant to the Stock
Option Plan will be evidenced by a written agreement executed by the Company and
the grantee, which will contain the terms, provisions and conditions of the
grant. Stock options may not be assigned or transferred during the lifetime of
the holder except as may be required by law or pursuant to a qualified domestic
relations order. The maximum term of each stock option is ten years from the
date of grant.
 
    In order for the options to qualify as ISOs, the aggregate fair market
value, determined on the date of grant, of the shares with respect to which the
ISOs are exercisable for the first time by the grantee during any calendar year
may not exceed $100,000. Payment by option holders upon exercise of an option
may be made (i) in cash, (ii) by tender to the Company of shares of the
Company's stock owned by the optionee having a fair market value, as determined
by the Compensation Committee (but without regard to any restrictions on
transferability applicable to such stock by reason of federal or state
securities laws or agreements with an underwriter for the Company), not less
than the exercise price, (iii) by delivery of a promissory note made by the
optionee in a form approved by the Company, (iv) by the assignment of the
proceeds of a sale of some or all of the shares being acquired upon the exercise
of the option, (v) by the withholding of shares being acquired upon exercise of
the option bearing a fair market value, as determined by the Compensation
Committee (but without regard to any restrictions on transferability
 
                                       54
<PAGE>
applicable to such stock by reason of federal or state securities laws or
agreements with an underwriter for the Company), not less than the exercise
price, or (vi) by any combination thereof. The Compensation Committee may at any
time or from time to time grant options which do not permit all of the foregoing
forms of consideration to be used in payment of the exercise price and/or which
otherwise restrict the use of one or more forms of consideration. In addition,
the Compensation Committee, in its sole discretion, may authorize the surrender
by an optionee of all or part of an unexercised stock option and authorize a
payment in consideration thereof of an amount equal to the difference between
the aggregate fair market value of the Common Stock subject to such stock option
and the aggregate option price of such Common Stock. In the Compensation
Committee's discretion, such payment may be made in cash, shares of Common Stock
with a fair market value on the date of surrender equal to the payment amount or
some combination thereof.
 
    The Stock Option Plan provides that outstanding options vest in their
entirety and become exercisable in the event of certain mergers, consolidations
or sales of all or substantially all of the assets of the Company, unless the
successor corporation assumes such options. As of the date hereof, options to
purchase 794,479 shares of Common Stock are outstanding under the Stock Option
Plan at exercise prices ranging from $0.19 to $11.20 per share.
 
    After the completion of the Offering, the Company expects to file with the
Commission a Registration Statement on Form S-8 covering the shares of Common
Stock issued pursuant to the Stock Option Plan and the shares of Common Stock
underlying options granted under the Stock Option Plan.
 
                              CERTAIN TRANSACTIONS
 
AGREEMENTS WITH LANDMARK GRAPHICS
 
    In connection with its initial capitalization, the Company entered into a
Technical Services Agreement with Landmark Graphics pursuant to which Landmark
Graphics agreed to grant to the Company ongoing licenses to use Landmark
Graphics software as it is first made available to Landmark Graphics customers.
In addition, the agreement provides for a strategic alliance between Landmark
Graphics and the Company, which enables the Company to request, and requires
Landmark Graphics to deliver, enhancements and modifications to existing
Landmark Graphics software and, in certain instances, to develop new software
for use in the Company's oil and gas exploration efforts. In exchange for such
rights, the Company has agreed to serve as an alpha test site for software
developed by Landmark Graphics. Neither this agreement nor any of the licenses
granted by Landmark Graphics to the Company contain any provisions with respect
to expiration or termination. In addition, the Company and Landmark Graphics are
also partners to an informal agreement pursuant to which the Company's employees
participate in Landmark Graphics' medical insurance plan, life insurance plans
and 401(k) plan. See "Business-- Significant Business Relationships."
 
    In connection with the informal agreements pursuant to which the Company
purchases medical and life insurance for its employees and their dependents as a
part of the Landmark Graphics benefit plan and those agreements which enable the
Company's employees to participate in the Landmark Graphics' 401(k) Plan, the
Company reimburses Landmark Graphics for all direct costs associated with such
benefits and programs and pays Landmark Graphics a quarterly administrative and
billing fee in an aggregate amount less than $1,500 annually. The Company
believes these informal arrangements result in an administrative convenience for
the Company, and may allow the Company's employees and their dependents to
obtain better insurance coverage than would be available from other plans that
the Company could obtain independently. Such arrangements do not result in any
material financial benefit to the Company since the Company reimburses Landmark
Graphics for all of costs which Landmark Graphics incurs in connection with such
arrangements. See "Business--Significant Business Relationships."
 
                                       55
<PAGE>
PURCHASES OF COMMON STOCK BY CERTAIN OFFICERS
 
    In January 1993, the Company issued 256,039 shares of restricted Common
Stock to each of Messrs. Ennis and Nester and Dr. Duncan at a price per share of
$0.06. As of November 30, 1996, 250,705 of the 256,039 shares issued to each of
Messrs. Ennis and Nester and Dr. Duncan were vested and the remaining shares
will vest in full on December 31, 1996.
 
    In November 1993, the Company issued 86,391 shares of restricted Common
Stock to each of Messrs. Ennis and Nester and Dr. Duncan at a price per share of
$0.19. As of November 30, 1996, 84,592 of the 86,391 shares issued to each of
Messrs. Ennis and Nester and Dr. Duncan were vested and the remaining shares
will vest in full on December 31, 1996.
 
                                       56
<PAGE>
                       PRINCIPAL AND SELLING STOCKHOLDERS
 
    The following table sets forth certain information regarding the beneficial
ownership of the Company's Common Stock, as of December 15, 1996, before and
after giving effect to the Offering, by (i) each person known to the Company to
own beneficially 5% or more of the Company's outstanding shares of Common Stock,
(ii) each director of the Company, (iii) each of the Named Executives, (iv) the
Selling Stockholder and (v) all executive officers and directors of the Company
as a group. All information with respect to beneficial ownership has been
furnished to the Company by the respective stockholders of the Company.
 
<TABLE>
<CAPTION>
                                                                              SHARES
                                                 SHARES BENEFICIALLY OWNED     BEING    SHARES BENEFICIALLY OWNED
                                                   BEFORE THE OFFERING(1)      SOLD      AFTER THE OFFERING(1)(2)
                                                 --------------------------  ---------  --------------------------
NAME                                                 NUMBER        PERCENT    NUMBER        NUMBER        PERCENT
- -----------------------------------------------  ---------------  ---------  ---------  ---------------  ---------
<S>                                              <C>              <C>        <C>        <C>              <C>
C. Eugene Ennis................................      483,502(3)      10.69%     --          483,502(3)       6.99%
Peter M. Duncan................................      370,899(4)       8.20%     --          370,899(4)       5.36%
Douglas C. Nester..............................      370,899(5)       8.20%     --          370,899(5)       5.36%
Jon W. Bayless.................................      676,581(6)      15.01%     --          676,581(6)       9.79%
Robert H. Chaney...............................      342,644(7)       7.60%     --          342,644(7)       4.96%
Charles E. Edwards.............................       19,587(8)       0.43%     --           19,587(8)       0.28%
Douglas C. Williamson..........................      760,851(9)      16.88%     --          760,851(9)      11.01%
NationsBanc Capital Corporation................      758,266(10)     16.83%     --          758,266(10)     10.98%
Citi Growth Fund L.P...........................      639,991(11)     14.21%     --          639,991(11)      9.27%
R. Chaney & Partners - 1993 L.P................      340,059(12)      7.55%     --          340,059(12)      4.92%
Landmark Graphics Corporation..................      449,862(13)      9.99%    100,000      349,862(13)      5.07%
Metropolitan Life Insurance Company............      284,350(14)      6.31%     --          284,350(14)      4.12%
Centennial Associates L.P./Centennial Energy
 Partners L.P..................................      245,861(15)      5.46%     --          245,861(15)      3.56%
All directors and executive officers as a group
 (9 persons)...................................    3,230,703(16)     68.27%     --        3,230,703(16)     45.30%
</TABLE>
 
- ------------------------
 
(1) Beneficial ownership is determined in accordance with the rules of the
    Commission. In computing the number of shares of Common Stock beneficially
    owned by a person and the percentage ownership of that person, shares of
    Common Stock subject to options and warrants held by that person that are
    currently exercisable or exercisable within 60 days of December 15, 1996 are
    deemed outstanding. Such shares, however, are not deemed outstanding for the
    purposes of computing the percentage ownership of any other person. Except
    as indicated in the footnotes to this table, each stockholder named in the
    table has sole voting and investment power with respect to the shares set
    forth opposite such stockholder's name. The information contained in this
    table is adjusted to give effect to the Transactions.
 
(2) Assumes the Underwriters' over-allotment option is not exercised.
 
(3) Includes vested and exercisable options to purchase 16,369 shares of Common
    Stock which were granted pursuant to the Stock Option Plan, excludes options
    to purchase 3,775 shares of Common Stock which are not vested.
 
(4) Includes vested and exercisable options to purchase 16,369 shares of Common
    Stock which were granted pursuant to the Stock Option Plan, excludes options
    to purchase 3,775 shares of Common Stock which are not vested.
 
(5) Includes vested and exercisable options to purchase 16,369 shares of Common
    Stock which were granted pursuant to the Stock Option Plan, excludes options
    to purchase 3,775 shares of Common Stock which are not vested.
 
                                       57
<PAGE>
(6) Includes vested and exercisable options to purchase 2,585 shares of Common
    Stock which were granted pursuant to the Stock Option Plan, excludes options
    to purchase 2,585 shares of Common Stock which are not vested. Includes
    639,991 shares beneficially owned by Citi Growth Fund L.P. Mr. Bayless is
    the controlling stockholder and sole director of Jon W. Bayless Inc., the
    general partner of Atlantic Partners L.P., the general partner of Citi
    Growth Fund L.P. beneficially owned by Citi Growth Fund L.P.
 
(7) Includes vested and exercisable options to purchase 2,585 shares of Common
    Stock which were granted pursuant to the Stock Option Plan, excludes options
    to purchase 2,585 shares of Common Stock which are not vested. Includes
    340,059 shares held by R. Chaney and Partners-1993 L.P. Mr. Chaney is the
    general partner of R. Chaney & Partners-1993 L.P.
 
(8) Includes vested and exercisable options to purchase 2,585 shares of Common
    Stock which were granted pursuant to the Stock Option Plan, excludes options
    to purchase 2,585 shares of Common Stock which are not vested.
 
(9) Includes vested and exercisable options to purchase 2,585 shares of Common
    Stock which were granted pursuant to the Stock Option Plan, excludes options
    to purchase 2,585 shares of Common Stock which are not vested. Includes
    758,266 shares of Common Stock held by NationsBanc Capital Corporation. Mr.
    Williamson is a Managing Director in the Venture Capital Group of
    NationsBanc Capital Corporation.
 
(10) The business address of NationsBanc Capital Corporation is 901 Main Street,
    Dallas, Texas 75202.
 
(11) The business address of Citi Growth Fund L.P. is c/o CitiGrowth Funds,
    Sycamore Partners, 989 Lenox Drive, Lawrenceville, New Jersey 08648.
 
(12) The business address of R. Chaney & Partners--1993 L.P. is 909 Fannin,
    Houston, Texas 77010.
 
(13) The business address of Landmark Graphics is 15150 Memorial Drive, Houston,
    Texas 77079. Landmark Graphics is a wholly-owned subsidiary of Halliburton
    Company.
 
(14) The business address of Metropolitan Life Insurance Company is c/o State
    Street Research, One Financial Center, Boston, Massachusetts 02111. State
    Street Research & Management Company, a wholly-owned subsidiary of
    Metropolitan Life Insurance Company, has the power to vote and dispose of
    these shares which are held by it on behalf of Metropolitan Life Insurance
    Company.
 
(15) The business address of each of Centennial Associates L.P. and Centennial
    Energy Partners L.P. is 900 Third Avenue, New York, New York 10022.
 
(16) Includes vested and exercisable options to purchase 227,371 shares of
    Common Stock which were granted pursuant to the Stock Option Plan, excludes
    options to purchase 164,882 shares of Common Stock which are not vested.
 
                          DESCRIPTION OF CAPITAL STOCK
 
GENERAL
 
    Effective upon completion of the Offering, the Company's authorized capital
stock will consist of (i) 20,000,000 shares of Common Stock, and (ii) 1,000,000
shares of Preferred Stock, of which 6,905,049 shares of Common Stock and no
shares of Preferred Stock will be issued and outstanding.
 
    The statements set forth below are brief summaries of all material
provisions of the Certificate of Incorporation and Bylaws which are filed as
exhibits to the Registration Statement of which this Prospectus is a part,
relating to the Company's capital stock. Such summaries do not purport to be
complete, and are subject to, and are qualified in their entirety by reference
to, such documents.
 
                                       58
<PAGE>
COMMON STOCK
 
    Holders of shares of Common Stock are entitled to one vote per share on all
matters on which the holders of Common Stock are entitled to vote and do not
have any cumulative voting rights. This means that the holders of more than 50%
of the shares voting for the election of directors can elect all of the
directors if they choose to do so; in such event, the holders of the remaining
shares of Common Stock will not be able to elect any person to the Board of
Directors. Subject to the rights of the holders of shares of any series of
Preferred Stock, holders of Common Stock are entitled to receive ratably such
dividends as may from time to time be declared by the Board of Directors of the
Company out of funds legally available therefor. See "Dividend Policy." Holders
of shares of Common Stock have no preemptive, conversion, redemption,
subscription or similar rights. In the event of a liquidation, dissolution or
winding up of the Company, whether voluntary or involuntary, holders of shares
of Common Stock are entitled to share ratably in the assets of the Company that
are legally available for distribution, if any, remaining after the payment or
provision for the payment of all debts and other liabilities of the Company and
the payment and setting aside for payment of any preferential amount due to the
holders of shares of any series of Preferred Stock. All outstanding shares of
Common Stock are, and all shares of Common Stock offered hereby when issued will
be, upon payment therefor, validly issued, fully-paid and nonassessable.
 
    At present there is no established trading market for the Common Stock. The
shares of Common Stock have been approved for quotation on the Nasdaq National
Market under the proposed symbol "TDXT," subject to official notice of issuance.
 
PREFERRED STOCK
 
    Prior to the completion of the Offering, the Certificate of Incorporation
will be amended to authorize the Board of Directors of the Company to issue from
time to time up to one million shares of Preferred Stock in one or more series
and to fix the rights, designations, preferences, qualifications, limitations
and restrictions thereof, including dividend rights, dividend rates, conversion
rights, voting rights, terms of redemption, redemption prices, liquidation
preferences and the number of shares constituting any series, without any
further action by the stockholders of the Company. The issuance of Preferred
Stock with voting rights could have an adverse effect on the voting power of
holders of Common Stock by increasing the number of outstanding shares having
voting rights. In addition, if the Board of Directors authorizes Preferred Stock
with conversion rights, the number of shares of Common Stock outstanding could
potentially be increased up to the authorized amount. The issuance of Preferred
Stock could decrease the amount of earnings and assets available for
distribution to holders of Common Stock. Any such issuance could also have the
effect of delaying, deterring or preventing a change in control of the Company
and may adversely affect the rights of holders of Common Stock. The Board of
Directors does not presently intend to issue any shares of Preferred Stock.
 
CERTAIN EFFECTS OF AUTHORIZED AND UNISSUED STOCK
 
    The unissued and unreserved shares of capital stock may be issued for a
variety of proper corporate purposes, including future public or private
offerings to raise additional capital or facilitate acquisitions. The Company's
Board of Directors does not currently have any plans to issue additional shares
of Common Stock or Preferred Stock (other than in connection with this Offering
or the Stock Option Plan).
 
    One of the effects of the existence of such unissued and unreserved shares
may be to enable the Company's Board of Directors to discourage an attempt to
change control of the Company (by means of a tender offer, proxy contest or
otherwise) and thereby to protect the continuity of the Company's management.
The issuance of shares of Preferred Stock, whether or not related to any attempt
to effect a change in control, may adversely affect the rights of the holders of
shares of Common Stock.
 
                                       59
<PAGE>
CERTAIN PROVISIONS OF THE CERTIFICATE OF INCORPORATION AND BYLAWS
 
    The Certificate of Incorporation provides that no director of the Company
shall be liable to the Company or its stockholders for monetary damages for
breach of his fiduciary duty as a director, except for liability (i) for any
breach of the director's duty of loyalty to the Company or its stockholders,
(ii) for acts or omissions not in good faith or that involve intentional
misconduct or a knowing violation of law, (iii) in respect of certain unlawful
dividend payments or stock redemptions or repurchases or (iv) for any
transaction from which the director derived an improper personal benefit. The
effect of these provisions is to eliminate the rights of the Company and its
stockholders (through stockholders' derivative suits on behalf of the Company)
to recover monetary damages against a director for breach of fiduciary duty as a
director (including breaches resulting from grossly negligent behavior), except
in the situations described above. These provisions will not limit the liability
of directors under the federal securities laws of the United States.
 
    The Bylaws require the Company to indemnify any legal representative,
director or officer of the Company or any person who is or was serving at the
request of the Company as a director, officer, employee or agent of another
corporation or of a partnership, joint venture, trust or other enterprise,
including service with respect to employee benefit plans, to the fullest extent
authorized by the DGCL. Prior to the completion of the Offering, the Company
intends to acquire officer's and directors' liability insurance in the amount of
$10 million for members of its Board of Directors and executive officers. In
addition to the indemnification provided in the Certificate of Incorporation and
Bylaws, prior to the completion of the Offering, the Company will enter into
agreements to indemnify its directors and officers.
 
    Prior to the completion of the Offering, the Certificate of Incorporation
and Bylaws will be amended to provide that the Company's Board of Directors will
be divided as equally as possible into three classes serving staggered, three
year terms. The Bylaws will be amended to establish advance notice procedures
with regard to the nomination, other than by or at the direction of the Board of
Directors, of candidates for election as directors and with regard to certain
matters to be brought before an annual meeting of stockholders of the Company.
In general, notice must be received by the Company not less than 80 days prior
to the meeting and must contain certain specified information concerning the
person to be nominated or the matter to be brought before the meeting and
concerning the stockholder submitting the proposal.
 
    OTHER PROVISIONS.  The Bylaws will be further amended to provide that
directors can be removed only for cause and only by the affirmative vote of
holders of at least 67% of the voting power of all then outstanding shares of
capital stock of the Company entitled to vote generally for the election of
directors (the "Voting Stock") and that a vacancy on the Company's Board of
Directors, including a vacancy created by an increase in the authorized number
of directors, may be filled only by a majority of the directors then in office
(and not by the stockholders unless no directors are then in office). Under the
DGCL, if at the time of filling any such vacancy the directors then in office
constitute less than a majority of the entire Board, the Delaware Court of
Chancery may order, upon the application of the holders of at least 10% of the
outstanding shares of capital stock of the Company entitled to vote for the
election of the directors filling such vacancies, that a meeting of stockholders
be held for the purpose of electing directors to fill such vacancies or to
replace directors filling such vacancies elected by the Company's Board of
Directors.
 
    In addition, the Certificate of Incorporation and Bylaws will be amended to
provide that stockholders are not permitted to call a special meeting of
stockholders or to require the Company's Board of Directors or officers to call
such a special meeting, that only a majority of the entire Board, certain
committees of the Company's Board of Directors, certain directors or the
president or chief executive officer will be able to call such a special meeting
and that stockholder action may be taken only at an annual or a special meeting
of stockholders and may not be taken by written consent.
 
    Prior to the completion of the Offering, the Certificate of Incorporation
and Bylaws will be amended to provide that the affirmative vote of the holders
of 67% of the Voting Stock will be required to amend,
 
                                       60
<PAGE>
modify or repeal any provisions of the Certificate of Incorporation or any
provision of the Bylaws discussed above. The Certificate of Incorporation will
be amended to provide that the Company's Board of Directors, pursuant to (but
only pursuant to) a resolution adopted by the affirmative vote of a majority of
the entire Board, will be able to amend, modify or repeal the Bylaws.
 
    Such provisions are intended to enhance the likelihood of continuity and
stability in the composition of the Company's Board of Directors and may have
the effect of delaying, deterring or preventing a future takeover or change in
control of the Company unless such takeover or change in control is approved by
the Company's Board of Directors. Such provisions may also render the removal of
the directors and management more difficult.
 
DELAWARE ANTI-TAKEOVER LAW
 
    The Company is subject to Section 203 of the DGCL because it is a Delaware
corporation. Section 203 of the DGCL prohibits certain transactions between a
Delaware corporation and an "interested stockholder," which is defined as a
person who, together with any affiliates or associates of such person,
beneficially owns, directly or indirectly, 15% or more of the outstanding voting
shares of a Delaware corporation. This provision prohibits certain business
combinations (defined broadly to include mergers, consolidations, sales or other
dispositions of assets having an aggregate value in excess of 10% of the
consolidated assets of the corporation, and certain transactions that would
increase the interested stockholder's proportionate share ownership in the
corporation) between an interested stockholder and a corporation for a period of
three years after the date the interested stockholder becomes an interested
stockholder, unless (i) prior to the date the interested stockholder becomes an
interested stockholder, the business combination or the transaction by which the
stockholder becomes an interested stockholder is approved by the corporation's
board of directors, (ii) the interested stockholder acquired at least 85% of the
voting stock of the corporation (other than stock held by directors who are also
officers or by certain employee stock plans) in the transaction in which it
became an interested stockholder or (iii) the business combination is approved
by a majority of the board of directors and by the affirmative vote of 66 2/3%
of the outstanding voting stock that is not owned by the interested stockholder.
 
REGISTRATION RIGHTS
 
    Holders of approximately 4,401,925 shares of Common Stock have certain
rights with respect to the registration of such shares under the Securities Act.
Pursuant to the terms of the Series C Preferred Stock Purchase Agreement, at any
time after the six month anniversary of the effective date of the Registration
Statement of which this Prospectus forms a part, holders of shares of Common
Stock acquired in connection with the Series C Preferred Stock offering may
require the Company, subject to certain conditions and limitations, to effect a
registration of all or part of the shares of Common Stock held by such persons
on an unlimited number of occasions. Also, the holders of shares of Common Stock
acquired in connection with the Series B Preferred Stock offering have certain
rights to require the Company, at any time after the six month anniversary of
the effective date of the Registration Statement of which this Prospectus forms
a part, to effect a registration of all or part of the shares of Common Stock
held by such persons on two occasions. The holders of 1,514,017 shares of Common
Stock issuable upon conversion of the Series C Preferred Stock (which include
shares which are issuable upon exercise of certain outstanding Warrants) also
have certain rights to require the Company to register such shares. At such time
as the Company is qualified to use a Registration Statement on Form S-3 to
register additional securities, the number of occasions on which the holders of
shares of Common Stock acquired in connection with the Series B Preferred Stock
may request registration of such shares shall be, subject to certain conditions,
unlimited in number. Additionally, if at any time the Company proposes to
register any of its securities under the Securities Act, either for its own
account or for the account of other security holders, holders of shares of
Common Stock issued in connection with each of the Series B Preferred Stock
offering and the Series C Preferred Stock offering, Messrs. Ennis and Nester,
Dr. Duncan and certain other key employees, are entitled to written notice of
such registration and to include therein shares of Common Stock held by
 
                                       61
<PAGE>
such holder. The registration rights of all parties are subject to certain
conditions and limitations, including the right of the underwriters of any
offering to limit the number of shares included in the registration. The Company
generally is required to bear all the fees, costs and expenses of such
registrations other than underwriting discounts and commissions. In connection
with this Offering, no registration rights have been exercised by any holder of
Common Stock except for Landmark Graphics.
 
TRANSFER AGENT AND REGISTRAR
 
    The transfer agent and registrar for the Common Stock is Continental Stock
Transfer & Trust Company, whose address is 2 Broadway, New York, New York 10004.
 
                        SHARES ELIGIBLE FOR FUTURE SALE
 
    Prior to the Offering, there has been no public market for the Common Stock.
Sales of a substantial amount of Common Stock in the public market, or the
perception that such sales may occur, could adversely affect the market price of
the Common Stock prevailing from time to time in the public market and could
impair the Company's ability to raise additional capital through the sale of its
equity securities in the future.
 
    Upon completion of the Offering, the Company will have 6,905,049 shares of
Common Stock outstanding (7,280,049 if the Underwriters' over-allotment option
is exercised in full), including 2,500,000 shares of Common Stock offered hereby
(2,875,000 if the Underwriters' over-allotment option is exercised in full) and
4,405,049 "restricted" shares of Common Stock. Of the restricted shares held by
persons other than "affiliates" of the Company within the meaning of Rule 144
promulgated under the Securities Act, 908,545 shares of Common Stock are
currently eligible for sale under Rule 144 as currently in effect, and the
remaining 593,171 shares of Common Stock held by persons other than affiliates
will become eligible for sale under Rule 144 at varying times commencing July
27, 1997.
 
    The shares of Common Stock offered in the Offering will be freely tradeable
without restriction or further registration under the Securities Act by persons
other than "affiliates" of the Company within the meaning of Rule 144
promulgated under the Securities Act. The holders of restricted shares generally
will be entitled to sell these shares in the public securities market without
registration under the Securities Act to the extent permitted by Rule 144 or any
exemption under the Securities Act.
 
    In general, under Rule 144 as currently in effect, if two years have elapsed
since the later of the date of acquisition of restricted shares from the Company
or any "affiliate" of the Company, the holder is entitled to sell within any
three-month period such number of shares of Common Stock that does not exceed
the greater of 1% of the then outstanding shares of Common Stock or the average
weekly trading volume of shares of Common Stock during the four calendar weeks
preceding the date on which notice of the sale is filed with the Commission.
Sales under Rule 144 are also subject to certain restrictions on the manner of
sale, notice requirements and the availability of current public information
about the Company. If three years have elapsed since the holder acquired the
restricted shares from the Company or from any "affiliate" of the Company, and
the holder is deemed not to have been an affiliate of the Company at any time
during the 90 days preceding a sale, such person will be entitled to sell such
Common Stock in the public market under Rule 144(k) without regard to the volume
limitations, manner of sale provisions, public information requirements or
notice requirements. The Commission has proposed an amendment to Rule 144 that
would reduce the holding period for shares subject to Rule 144 to become
eligible for sale in the public market. This proposal, if adopted, would
increase the number of shares of Common Stock eligible for immediate sale
following the expiration of the "lock-up period" described below.
 
    After the completion of the Offering, the Company intends to file a
registration statement under the Securities Act to register shares of Common
Stock reserved for issuance under or issued pursuant to the Stock Option Plan,
thereby permitting the resale of such shares by non-affiliates in the public
market without restriction under the Securities Act. See "Management--Stock
Option Plan."
 
                                       62
<PAGE>
    The Company and certain of its stockholders have entered into "lock-up"
agreements with the Underwriters, providing that, subject to certain exceptions,
they will not, for a period of 180 days following the date of this Prospectus,
without the prior written consent of Howard, Weil, Labouisse, Friedrichs
Incorporated, offer, sell or contract to sell, or otherwise dispose of, directly
or indirectly, or announce an offering of, any shares of Common Stock or any
securities convertible into, or exchangeable for, shares of Common Stock,
provided that, the Company may issue and sell shares of Common Stock pursuant to
the Stock Option Plan. See "Underwriting."
 
                                       63
<PAGE>
                                  UNDERWRITING
 
    The Underwriters named below (the "Underwriters"), for whom Howard, Weil,
Labouisse, Friedrichs Incorporated and Petrie Parkman & Co., Inc. are acting as
representatives (the "Representatives"), have severally agreed, subject to the
terms and conditions contained in the Underwriting Agreement, to purchase from
the Company and the Selling Stockholder the number of shares of Common Stock set
forth below opposite their respective names:
 
<TABLE>
<CAPTION>
                                                        NUMBER
                   UNDERWRITERS                       OF SHARES
- --------------------------------------------------  --------------
<S>                                                 <C>
Howard, Weil, Labouisse, Friedrichs
  Incorporated....................................        850,000
Petrie Parkman & Co. .............................        850,000
Bear, Stearns & Co., Inc. ........................        100,000
J.P. Morgan Securities Inc. ......................        100,000
Morgan Stanley & Co. Incorporated.................        100,000
Wasserstein Perella Securities, Inc. .............        100,000
Hanifen, Imhoff Inc. .............................         50,000
Josephthal, Lyon & Ross, Inc. ....................         50,000
Legg Mason Wood Walker, Incorporated..............         50,000
McDonald & Company Securities, Inc. ..............         50,000
Needham & Company, Inc. ..........................         50,000
Rauscher Pierce Refsnes, Inc. ....................         50,000
Sanders Morris Mundy Inc. ........................         50,000
Van Kasper & Company..............................         50,000
                                                    --------------
    Total.........................................      2,500,000
                                                    --------------
                                                    --------------
</TABLE>
 
    The Company and the Selling Stockholder are obligated to sell, and the
Underwriters are obligated to purchase, all of the shares of Common Stock
offered hereby if any are purchased.
 
    The Underwriters, through their Representatives, have advised the Company
and the Selling Stockholder that they propose to offer the Common Stock
initially at the public offering price set forth on the cover page of this
Prospectus; that the Underwriters may allow selected dealers a concession of
$0.46 per share; and that such dealers may reallow a concession of $0.10 per
share to certain other dealers. After the public offering, the offering price
and the concessions may be changed by the Representatives.
 
    The Company has granted to the Underwriters an option, exercisable for 30
days from the date of this Prospectus, to purchase up to 375,000 additional
shares of Common Stock at the initial public offering price, less underwriting
discounts and commissions, as set forth on the cover page of this Prospectus.
The Underwriters may exercise such option solely for the purpose of covering
over-allotments incurred in the sale of the shares of Common Stock offered
hereby. To the extent such option to purchase is exercised, each Underwriter
will become obligated, subject to certain conditions, to purchase approximately
the same percentage of such additional shares as the number of shares set forth
next to such Underwriter's name in the table above bears to the total number of
shares set forth in the table above. The Underwriters may exercise such option
only to cover over-allotments in connection with the sale of the 2,500,000
shares of Common Stock offered hereby.
 
    The Company and the Selling Stockholder have agreed to indemnify the several
Underwriters or contribute to losses arising out of certain liabilities,
including liabilities under the Securities Act of 1933, as amended.
 
    The Company and each of its directors and executive officers and certain of
its stockholders have agreed that they will not, directly or indirectly, offer,
sell, offer to sell, contract to sell, pledge, grant any option to purchase or
otherwise sell or dispose (or announce any offer, sale, offer of sale, contract
of sale,
 
                                       64
<PAGE>
pledge, grant of an option to purchase or other disposition) of any shares of
Common Stock or any securities convertible into, or exchangeable or exercisable
for, shares of Common Stock or other capital stock of the Company, without the
prior written consent of Howard, Weil, Labouisse, Friedrichs Incorporated on
behalf of the Underwriters for a period of 180 days after the date of this
Prospectus, except for (i) shares issued in connection with any employee benefit
plan of the Company existing as of the date of this Prospectus, (ii) shares
issued in connection with the conversion of the Series C Preferred Stock into
Common Stock and the Reverse Split to be effected prior to the Offering and
(iii) shares issued in connection with the Offering.
 
    Prior to the Offering, there has been no public market for the Common Stock.
The initial public offering price of the Common Stock has been determined by
negotiation among the Company and the Representatives. Among the factors to be
considered in determining the initial public offering price include the
information set forth in this Prospectus and otherwise available to the
Representatives, the history of and future prospects for the industry in which
the Company competes, the skills and experience of the Company's management, the
general conditions of the securities market at the time of the Offering, and the
market prices of securities and certain financial and operating information of
companies engaged in activities similar to those of the Company. There can be no
assurance that the price at which shares of Common Stock will sell in the public
market after the Offering will not be lower than the price at which they are
sold in the Offering by the Underwriters.
 
    Peter Gough, a Director of Petrie Parkman & Co., Inc., is the beneficial
owner of 51,007 shares of the Company's Common Stock.
 
                                 LEGAL MATTERS
 
    The validity of the shares will be passed upon for the Company by Kelley
Drye & Warren LLP, New York, New York. Frederic A. Rubinstein, a partner of
Kelley Drye & Warren LLP is the beneficial owner of 18,154 shares of Common
Stock. Certain legal matters in connection with the Offering will be passed upon
for the Underwriters by Andrews & Kurth LLP, Houston, Texas.
 
                                    EXPERTS
 
    The audited balance sheets of the Company as of December 31, 1994 and 1995,
and the related statements of operations, changes in common stockholders' equity
(deficit) and cash flows for the period from inception of operations (January 6,
1993) to December 31, 1993 and for the years ended December 31, 1994 and 1995,
included in this registration statement have been audited by Arthur Andersen
LLP, independent public accountants, as indicated in their report with respect
thereto, and are included herein in reliance upon the authority of said firm as
experts in giving said report.
 
    The Reserve Report of Ryder Scott, set forth in this Prospectus as Appendix
A, has been included herein in reliance upon the authority of that firm as an
expert in petroleum engineering.
 
                             ADDITIONAL INFORMATION
 
    The Company has filed with the Commission a Registration Statement on Form
S-1 under the Securities Act with respect to the shares being sold in the
Offering. This Prospectus, which constitutes a part of the Registration
Statement, does not contain all the information set forth in the Registration
Statement and the exhibits and schedule thereto, certain portions of which have
been omitted as permitted by the rules and regulations of the Commission. For
further information with respect to the Company and the Common Stock, reference
is made to the Registration Statement and the exhibits and schedule filed as a
part thereof. Statements contained in the Prospectuses as to the contents of any
contract, agreement or other document referred to are brief summaries of the
material provisions thereof but are not necessarily complete, and in each
instance reference is made to the copy of such contract, agreement or other
document filed as an exhibit to the Registration Statement, each such statement
being qualified in all
 
                                       65
<PAGE>
respects by such reference. The Registration Statement, including exhibits and
schedules thereto, may be inspected without charge at the Commission's principal
office at 450 Fifth Street, N.W., Judiciary Plaza, Room 1024, Washington, D.C.
20549 and at the following regional offices of the Commission: Citicorp Center,
500 West Madison Street, Suite 1400, Chicago, Illinois 60661-2511 and at Seven
World Trade Center, Suite 1300, New York, New York 10048. Copies of all or any
portion of the Registration Statement may be obtained from the Public Reference
Section of the Commission at 450 Fifth Street, N.W., Judiciary Plaza,
Washington, D.C. 20549, upon payment of fees prescribed by the Commission.
 
    As a result of the Offering, the Company will be subject to the
informational requirements of the Exchange Act and, in accordance therewith,
will file periodic reports and other information with the Commission at 450
Fifth Street, N.W., Washington, D.C. 20549. Copies of the reports and
information so filed can be obtained from the Public Reference Section of the
Commission, upon payment of fees prescribed by the Commission. So long as the
Company is subject to the periodic reporting requirements of the Exchange Act,
it will furnish the reports and other information required thereby to the
Commission. The Company intends to furnish holders of its Common Stock with
annual reports containing among other information audited financial statements
certified by an independent accounting firm. The Company also intends to furnish
such other reports as it may determine or as may be required by law.
 
    The Commission maintains a Web site that contains reports, proxy statements
and other information regarding registrants that file electronically with the
Commission. The address of the Commission's Web site is http:\\www.sec.gov.
 
                                       66
<PAGE>
                       GLOSSARY OF CERTAIN INDUSTRY TERMS
 
    The definitions set forth below shall apply to the indicated terms as used
in this Prospectus. All volumes of natural gas referred to herein are stated at
the legal pressure base of the state or area where the reserves exist and at 60
degrees Fahrenheit and in most instances are rounded to the nearest major
multiple.
 
    2-D SEISMIC. The method by which a cross-section of the earth's subsurface
is created through the interpretation of reflecting seismic data collected along
a single source profile.
 
    3-D IMAGING. The method by which a three dimensional image of the earth's
subsurface is created through the interpretation of reflection seismic data
collected over surface grid. 3-D seismic surveys allow for a more detailed
understanding of the subsurface than do conventional surveys and contribute
significantly to field appraisal, development and production.
 
    AVO ANALYSIS. A geophysical technique depending upon the principle of
reflection coefficient change with angle of incidence that when applied under
certain conditions allows interpreters to distinguish gas bearing sands from
other bright spot causes such as hard streaks, wet sands and lignite.
 
    BCF. Billion cubic feet of natural gas.
 
    BCFE. Billion cubic feet equivalent, determined using the ratio of six Mcf
of natural gas to one Bbl of crude oil, condensate or natural gas liquids.
 
    BBL. One stock tank barrel, or 42 U.S. gallons liquid volume, used herein in
reference to crude oil or other liquid hydrocarbons.
 
    BBLS/D. Stock tank barrels per day.
 
    COMPLETION. The installation of permanent equipment for the production of
oil or gas, or in the case of a dry hole, the reporting of abandonment to the
appropriate agency.
 
    DISCOUNTED PRESENT VALUE. A method of determining the present value of
proved reserves in accordance with Commission requirements. Under the Commission
method, the future net revenues before income taxes from proved reserves are
estimated assuming that oil and natural gas prices and production costs remain
constant. The resulting stream of revenues is then discounted at the rate of 10%
per year to obtain the present value.
 
    DRY HOLE OR WELL. A well found to be incapable of producing hydrocarbons in
sufficient quantities such that proceeds from the sale of such production exceed
production expenses and taxes.
 
    EXPLORATORY WELL. A well drilled to find and produce oil or gas reserves not
classified as proved, to find a new reservoir in a field previously found to be
productive of oil or gas in another reservoir or to extend a known reservoir.
 
    FARM-IN OR FARM-OUT. An agreement whereunder the owner of a working interest
in an oil and gas lease assigns the working interest or a portion thereof to
another party who desires to drill on the leased acreage. Generally, the
assignee is required to drill one or more wells in order to earn its interest in
the acreage. The assignor usually retains a royalty or reversionary interest in
the lease. The interest received by an assignee is a "farm-in" while the
interest transferred by the assignor is a "farm-out."
 
    FIELD. An area consisting of a single reservoir or multiple reservoirs all
grouped on or related to the same individual geological structural feature
and/or stratigraphic condition.
 
    GPS. Global positioning system.
 
    GROSS ACRES OR GROSS WELLS. The total acres or wells, as the case may be, in
which a working interest is owned.
 
                                       67
<PAGE>
    MBBLS. One thousand barrels of crude oil or other liquid hydrocarbons.
 
    MCF. One thousand cubic feet of natural gas.
 
    MCF/D. One thousand cubic feet of natural gas per day.
 
    MCFE. One thousand cubic feet equivalent, determined using the ratio of six
Mcf of natural gas to one Bbl of crude oil, condensate or natural gas liquids.
 
    MMBBLS. One million barrels of crude oil or other liquid hydrocarbons.
 
    MMBOE. One million barrels of oil equivalent.
 
    MMCF. One million cubic feet of natural gas.
 
    MMCFE/D. One million cubic feet of natural gas equivalent per day.
 
    NET ACRES OR NET WELLS. The sum of the fractional working interests owned in
gross acres or gross wells.
 
    PAY. An industry term used to describe reservoirs in the subsurface which
contain hydrocarbons.
 
    PRESENT VALUE. When used with respect to oil and gas reserves, the estimated
future gross revenue to be generated from the production of proved reserves, net
of estimated production and future development costs, using prices and costs in
effect as of the date indicated, without giving effect to non-property related
expenses such as general and administrative expenses, debt service and future
income tax expense or to depreciation, depletion and amortization, discounted
using an annual discount rate of 10%.
 
    PRODUCTIVE WELL. A well that is found to be capable of producing
hydrocarbons in sufficient quantities such that proceeds from the sale of such
production exceed production expenses and taxes.
 
    PROVED DEVELOPED PRODUCING RESERVES. Proved developed reserves that are
expected to be recovered from completion intervals currently open in existing
wells and able to produce to market.
 
    PROVED DEVELOPED RESERVES. Proved reserves that can be expected to be
recovered from existing wells with existing equipment and operating methods.
 
    PROVED DEVELOPED NONPRODUCING RESERVES. Proved developed reserves expected
to be recovered from zones behind casing in existing wells.
 
    PROVED RESERVES. The estimated quantities of crude oil, natural gas and
natural gas liquids which geological and engineering data demonstrate with
reasonable certainty to be recoverable in future years from known reservoirs
under existing economic and operating conditions.
 
    PROVED UNDEVELOPED RESERVES. Proved reserves that are expected to be
recovered from new wells on undrilled acreage or from existing wells where a
relatively major expenditure is required for recompletion.
 
    RECOMPLETION. The completion for production of an existing well bore in
another formation from that in which the well has been previously completed.
 
    RESERVOIR. A porous and permeable underground formation containing a natural
accumulation of producible oil and/or gas that is confined by impermeable rock
or water barriers and is individual and separate from other reservoirs.
 
    TCF. Trillion cubic feet of natural gas.
 
    UNDEVELOPED ACREAGE. Lease acreage on which wells have not been drilled or
completed to a point that would permit the production of commercial quantities
of oil and gas regardless of whether such acreage contains proved reserves.
 
    WORKING INTEREST. The operating interest which gives the owner the right to
drill, produce and conduct operating activities on the property and a share of
production.
 
                                       68
<PAGE>
                         INDEX TO FINANCIAL STATEMENTS
 
<TABLE>
<CAPTION>
                                                                                                              PAGE
                                                                                                            ---------
<S>                                                                                                         <C>
Pro Forma Financial Statements
 
Introduction to Pro forma Financial Statements............................................................        F-2
 
Pro forma Balance Sheet as of September 30, 1996..........................................................        F-3
 
Pro forma Statement of Operations for the nine month period ended September 30, 1996......................        F-4
 
Pro forma Statement of Operations for the year ended December 31, 1995....................................        F-5
 
Notes to Pro forma Financial Statements...................................................................        F-6
 
Historical Financial Statements
 
Report of Independent Public Accountants..................................................................        F-7
 
Balance Sheets as of December 31, 1994 and 1995 and unaudited as of September 30, 1996....................        F-8
 
Statements of Operations for the period from inception of operations (January 6, 1993) through December
 31, 1993, the years ended December 31, 1994 and 1995 and unaudited for the nine month periods ended
 September 30, 1995 and 1996..............................................................................        F-9
 
Statements of Changes in Common Stockholders' Equity (Deficit) for the period from inception of operations
 (January 6, 1993) through December 31, 1993, the years ended December 31, 1994 and 1995 and unaudited for
 the nine month period ended September 30, 1996...........................................................       F-10
 
Statements of Cash Flows for the period from inception of operations (January 6, 1993) through December
 31, 1993, the years ended December 31, 1994 and 1995 and unaudited for the nine month periods ended
 September 30, 1995 and 1996..............................................................................       F-11
 
Notes to Financial Statements.............................................................................       F-12
</TABLE>
 
                                      F-1
<PAGE>
            PRO FORMA FINANCIAL STATEMENTS OF 3DX TECHNOLOGIES INC.
 
    The accompanying unaudited pro forma balance sheet as of September 30, 1996
and statements of operations for the year ended December 31, 1995 and the nine
month period ended September 30, 1996 give effect to certain transactions which
will take place upon the closing of the Offering as if the transactions had
taken place on September 30, 1996 in the case of the pro forma balance sheet
and, January 1, 1995 in the case of the pro forma statements of operations.
 
    The pro forma financial statements do not purport to present the financial
position or results of operations of 3DX Technologies Inc. (the "Company") had
the transactions to be effected at the closing of this offering actually been
completed as of the dates indicated. In addition, the pro forma financial
statements are not necessarily indicative of the results of future operations of
the Company and should be read in conjunction with the Company's historical
financial statements and notes thereto contained elsewhere herein.
 
                                      F-2
<PAGE>
                             3DX TECHNOLOGIES INC.
 
                            PRO FORMA BALANCE SHEET
 
                                  (UNAUDITED)
 
                                     ASSETS
 
<TABLE>
<CAPTION>
                                                                       HISTORICAL                          PRO FORMA
                                                                      SEPTEMBER 30,      PRO FORMA       SEPTEMBER 30,
                                                                          1996          ADJUSTMENTS          1996
                                                                      -------------  ------------------  -------------
<S>                                                                   <C>            <C>                 <C>
Current Assets:
  Cash and cash equivalents.........................................   $ 3,762,208   $       --           $ 3,762,208
  Accounts receivable...............................................       287,548           --               287,548
  Prepaid expenses..................................................        81,334           --                81,334
                                                                      -------------  ------------------  -------------
      Total current assets..........................................     4,131,090           --             4,131,090
                                                                      -------------  ------------------  -------------
Property and equipment:
  Oil and gas properties (full-cost method-- including $1,993,753,
    not subject to depletion, depreciation and amortization)........     7,435,604           --             7,435,604
  Technical interpretation equipment................................     1,496,925           --             1,496,925
  Office furniture and equipment....................................       162,717           --               162,717
  Office leasehold improvements.....................................        39,101           --                39,101
                                                                      -------------  ------------------  -------------
                                                                         9,134,347           --             9,134,347
                                                                      -------------  ------------------  -------------
  Less accumulated depletion, depreciation and amortization.........    (4,281,588)          --            (4,281,588)
                                                                      -------------  ------------------  -------------
                                                                         4,852,759           --             4,852,759
Other assets:
  Deposits..........................................................         7,886           --                 7,886
                                                                      -------------  ------------------  -------------
  Organization costs, net of accumulated amortization...............         2,405           --                 2,405
                                                                      -------------  ------------------  -------------
                                                                       $ 8,994,140   $       --           $ 8,994,140
                                                                      -------------  ------------------  -------------
                                                                      -------------  ------------------  -------------
                                       LIABILITIES, REDEEMABLE PREFERRED STOCK
                                      AND COMMON STOCKHOLDERS' EQUITY (DEFICIT)
Current Liabilities:
  Accounts payable..................................................   $   620,557           --           $   620,557
  Accrued liabilities...............................................        74,883           --                74,883
                                                                      -------------  ------------------  -------------
      Total current liabilities.....................................       695,440           --               695,440
                                                                      -------------  ------------------  -------------
Dividends payable on Series C preferred stock.......................       780,423      (780,423)(C)(D)       --
                                                                      -------------  ------------------  -------------
Commitments (Note 10)
Mandatorily redeemable Series B preferred stock, $.01 par value,
  $100 per share redemption price, 200,000 shares authorized, issued
  and outstanding: 66,871 shares actual, no shares pro forma........                     376,676(B)
                                                                         6,310,424    (6,687,100)(B)          --
                                                                      -------------  ------------------  -------------
Mandatorily redeemable Series C senior preferred stock, $.01 par
  value, $3 per share redemption price, 3,300,000 shares authorized,
  issued and outstanding: 2,662,241 shares actual, no shares pro
  forma.............................................................     7,912,368    (7,912,368)(A)          --
                                                                      -------------  ------------------  -------------
Common stockholders' equity (deficit):
  Common stock, $.01 par value, 12,000,000 shares authorized, issued
    and outstanding: 2,991,032 shares actual, 5,121,167 shares pro
    forma...........................................................        29,910        13,764(A)            51,212
                                                                                           7,538(D)
                                                                      -------------  ------------------  -------------
  Paid-in capital...................................................     3,062,337     7,898,604(A)        18,420,926
                                                                                       7,459,985(D)
  Deferred compensation related to certain stock options............    (1,529,773)                        (1,529,773)
  Notes receivable from stock sales.................................       (16,448)                           (16,448)
  Accumulated deficit...............................................    (8,250,541)     (376,676)(B)       (8,627,217)
                                                                      -------------  ------------------  -------------
      Total common stockholder's equity (deficit)...................    (6,704,515)   15,003,215            8,298,700
                                                                      -------------  ------------------  -------------
                                                                       $ 8,994,140   $       --           $ 8,994,140
                                                                      -------------  ------------------  -------------
                                                                      -------------  ------------------  -------------
</TABLE>
 
    The accompanying notes are an integral part of these pro forma financial
                                   statements
 
                                      F-3
<PAGE>
                             3DX TECHNOLOGIES INC.
 
                       PRO FORMA STATEMENT OF OPERATIONS
 
                                  (UNAUDITED)
 
<TABLE>
<CAPTION>
                                                                   HISTORICAL                           PRO FORMA
                                                                NINE MONTH PERIOD                   NINE MONTH PERIOD
                                                               ENDED SEPTEMBER 30,    PRO FORMA       SEPTEMBER 30,
                                                                      1996           ADJUSTMENTS          1996
                                                               -------------------  --------------  -----------------
<S>                                                            <C>                  <C>             <C>
Revenues:
  Oil and gas................................................     $     408,459                       $     408,459
  Rental Income..............................................           120,098                             120,098
  Interest and other.........................................           217,678                             217,678
                                                               -------------------  --------------  -----------------
      Total revenues.........................................           746,235                             746,235
                                                               -------------------  --------------  -----------------
Costs and Expenses:
  Lease operating............................................            28,463                              28,463
  Production and ad valorem taxes............................            22,764                              22,764
  Impairment of oil and gas properties.......................         1,476,690                           1,476,690
  Depletion, depreciation, and amortization..................           463,573                             463,573
  General and administrative.................................         1,343,660                           1,343,660
  Interest and amortization of loan guarantee fees...........               289                                 289
                                                               -------------------  --------------  -----------------
      Total costs and expenses...............................         3,335,439                           3,335,439
                                                               -------------------  --------------  -----------------
Net loss.....................................................        (2,589,204)                         (2,589,204)
Dividends on preferred stock.................................          (505,167)       505,167(E)          --
Accretion on preferred stock.................................           (41,133)        41,133(F)          --
                                                               -------------------  --------------  -----------------
Net loss applicable to common stockholders...................     $  (3,135,504)    $  546,300        $  (2,589,204)
                                                               -------------------  --------------  -----------------
                                                               -------------------  --------------  -----------------
Primary and fully diluted net loss per common share..........                                         $        (.49)
                                                                                                    -----------------
                                                                                                    -----------------
Weighted average number of common shares outstanding.........                                             5,337,553
                                                                                                    -----------------
                                                                                                    -----------------
</TABLE>
 
    The accompanying notes are an integral part of these pro forma financial
                                   statements
 
                                      F-4
<PAGE>
                             3DX TECHNOLOGIES INC.
 
                       PRO FORMA STATEMENT OF OPERATIONS
 
                                  (UNAUDITED)
 
<TABLE>
<CAPTION>
                                                                        HISTORICAL                         PRO FORMA
                                                                        YEAR ENDED                        YEAR ENDED
                                                                       DECEMBER 31,       PRO FORMA      DECEMBER 31,
                                                                           1995          ADJUSTMENTS         1995
                                                                       -------------  -----------------  -------------
<S>                                                                    <C>            <C>                <C>
Revenues:
  Oil and gas........................................................  $     274,511                     $     274,511
  Rental Income......................................................         58,195                            58,195
  Interest and other.................................................        236,186                           236,186
                                                                       -------------  -----------------  -------------
      Total revenues.................................................        568,892                           568,892
                                                                       -------------  -----------------  -------------
Costs and Expenses:
  Lease operating....................................................         60,877                            60,877
  Production and ad valorem taxes....................................         17,656                            17,656
  Impairment of oil and gas properties...............................      1,627,321                         1,627,321
  Depletion, depreciation, and amortization..........................        446,350                           446,350
  General and administrative.........................................        905,063                           905,063
  Interest and amortization of loan guarantee fees...................       --                                --
                                                                       -------------  -----------------  -------------
  Total costs and expenses...........................................      3,057,267                         3,057,267
                                                                       -------------  -----------------  -------------
Net loss.............................................................     (2,488,375)                       (2,488,375)
Dividends on preferred stock.........................................     (1,058,956)     1,058,956(E)        --
Accretion on preferred stock.........................................        (48,408)        48,408(F)        --
                                                                       -------------  -----------------  -------------
Net loss applicable to common stockholders...........................  $  (3,595,739) $   1,107,364      $  (2,488,375)
                                                                       -------------  -----------------  -------------
                                                                       -------------  -----------------  -------------
Primary and fully diluted net loss per common share..................                                    $        (.47)
                                                                                                         -------------
                                                                                                         -------------
Weighted average number of common shares outstanding.................                                        5,335,982
                                                                                                         -------------
                                                                                                         -------------
</TABLE>
 
    The accompanying notes are an integral part of these pro forma financial
                                   statements
 
                                      F-5
<PAGE>
                             3DX TECHNOLOGIES INC.
 
                    NOTES TO PRO FORMA FINANCIAL STATEMENTS
 
                                  (UNAUDITED)
 
BASIS OF PRESENTATION
 
    The following pro forma adjustments have been prepared as if the
transactions to be effected at the closing of the Offering had taken place on
September 30, 1996, in the case of the pro forma balance sheet or as of January
1, 1995, in the case of the pro forma statements of operations. The adjustments
are based upon currently available information and certain estimates and
assumptions, and therefore the actual adjustments made to effect the
transactions may differ from the pro forma adjustments. However, management
believes that the assumptions provide a reasonable basis for presenting the
significant effects of the transactions as contemplated and that the pro forma
adjustments give appropriate effect to these assumptions and are properly
applied in the pro forma financial information.
 
PRO FORMA ADJUSTMENTS TO THE BALANCE SHEET
 
A. Reflects the conversion of each of the 2,662,241 shares of Series C Preferred
    Stock issued and outstanding as of the date of this Prospectus into
    1,376,379 shares of common stock (giving effect to the .517 Reverse Common
    Stock Split), with a total recorded value of $7,912,368. The recorded value
    of $7,912,368 has been allocated to Common Stock and Paid in capital in the
    amounts of $13,764 and $7,898,604 respectively.
 
B.  Reflects the redemption immediately after the closing of this Offering of
    all issued and outstanding shares of the Series B Preferred Stock (including
    the effects of a $376,676 redemption premium recorded against accumulated
    deficit which adjusts the Series B Preferred Stock carrying value to the
    liquidation price of $100 per share).
 
C.  Reflects the payment immediately after the closing of this Offering of
    Series C Preferred Stock dividends currently accrued on the September
    30,1996 balance sheet of $780,423.
 
D. Reflects the issuance of 753,756 shares of common stock at $11 per share
    pursuant to the Offering, net of expenses, to fund payments of $780,423 to
    pay accrued dividends and $6,687,100 for the redemption of the Series B
    Mandatorily Redeemable Preferred Stock.
 
PRO FORMA ADJUSTMENTS TO THE STATEMENT OF OPERATIONS
 
E.  Reflects the elimination of accrued dividends on Series B and Series C
    Mandatorily Redeemable Preferred Stock.
 
F.  Reflects the elimination of accretion on Series B and Series C Mandatorily
    Redeemable Preferred Stock.
 
                                      F-6
<PAGE>
                    REPORT OF INDEPENDENT PUBLIC ACCOUNTANTS
 
To the Stockholders and Board of Directors
    of 3DX Technologies Inc.:
 
    We have audited the accompanying balance sheets of 3DX Technologies Inc. (a
Delaware corporation) as of December 31, 1994 and 1995, and the related
statements of operations, changes in common stockholders' equity (deficit) and
cash flows for the period from inception of operations (January 6, 1993) through
December 31, 1993 and for the years ended December 31, 1994 and 1995. These
financial statements are the responsibility of the Company's management. Our
responsibility is to express an opinion on these financial statements based on
our audits.
 
    We conducted our audits in accordance with generally accepted auditing
standards. Those standards require that we plan and perform the audit to obtain
reasonable assurance about whether the financial statements are free of material
misstatement. An audit includes examining, on a test basis, evidence supporting
the amounts and disclosures in the financial statements. An audit also includes
assessing the accounting principles used and significant estimates made by
management, as well as evaluating the overall financial statement presentation.
We believe that our audits provide a reasonable basis for our opinion.
 
    In our opinion, the financial statements referred to above present fairly,
in all material respects, the financial position of 3DX Technologies Inc. as of
December 31, 1994 and 1995, and the results of its operations and its cash flows
for the period from inception of operations (January 6, 1993) through December
31, 1993 and for the years ended December 31, 1994 and 1995, in conformity with
generally accepted accounting principles.
 
                                          ARTHUR ANDERSEN LLP
 
Houston, Texas
May 7, 1996
 
                                      F-7
<PAGE>
                             3DX TECHNOLOGIES INC.
 
                                 BALANCE SHEETS
 
                                     ASSETS
 
<TABLE>
<CAPTION>
                                                                                     DECEMBER 31,
                                                                                ----------------------
                                                                                   1994        1995
                                                                                ----------  ----------
                                                                                                        SEPTEMBER 30,
                                                                                                        -------------
                                                                                                            1996
                                                                                                        -------------
                                                                                                         (UNAUDITED)
                                                                                        AS RESTATED (NOTE 2)
                                                                                -------------------------------------
<S>                                                                             <C>         <C>         <C>
Current assets:
  Cash and cash equivalents...................................................  $2,444,014  $5,704,014   $ 3,762,208
  Securities held to maturity.................................................      --       1,595,167       --
  Accounts receivable.........................................................      68,219     113,704       287,548
  Prepaid expenses............................................................       9,598      85,786        81,334
                                                                                ----------  ----------  -------------
      Total current assets....................................................   2,521,831   7,498,671     4,131,090
                                                                                ----------  ----------  -------------
Property and equipment:
  Oil and gas properties (full-cost method--including $828,321, $1,375,145 and
    $1,993,753, respectively, not subject to depletion, depreciation and
    amortization).............................................................   2,403,467   4,023,869     7,435,604
  Technical interpretation equipment..........................................     464,105   1,083,925     1,496,925
  Office furniture and equipment..............................................      73,444     139,570       162,717
  Office leasehold improvements...............................................      --          31,307        39,101
                                                                                ----------  ----------  -------------
                                                                                 2,941,016   5,278,671     9,134,347
  Less accumulated depletion, depreciation and amortization...................    (271,839) (2,343,578)   (4,281,588)
                                                                                ----------  ----------  -------------
                                                                                 2,669,177   2,935,093     4,852,759
Other assets:
  Deposits....................................................................      --          12,886         7,886
  Organization costs, net of accumulated amortization.........................       5,787       3,854         2,405
                                                                                ----------  ----------  -------------
                                                                                $5,196,795  $10,450,504  $ 8,994,140
                                                                                ----------  ----------  -------------
                                                                                ----------  ----------  -------------
 
                                       LIABILITIES, REDEEMABLE PREFERRED STOCK
                                      AND COMMON STOCKHOLDERS' EQUITY (DEFICIT)
 
Current liabilities:
  Accounts payable............................................................  $  365,539  $  194,742   $   620,557
  Accrued liabilities.........................................................      53,706      39,166        74,883
                                                                                ----------  ----------  -------------
      Total current liabilities...............................................     419,245     233,908       695,440
                                                                                ----------  ----------  -------------
Dividends payable on Series C preferred stock.................................      --         275,256       780,423
                                                                                ----------  ----------  -------------
Commitments (Note 10)
Mandatorily redeemable Series B preferred stock, $.01 par value, $100 per
  share redemption price, 200,000 shares authorized, 59,034, 66,871 and 66,871
  shares issued and outstanding, respectively.................................   5,451,522   6,277,826     6,310,424
                                                                                ----------  ----------  -------------
Mandatorily redeemable Series C senior preferred stock, $.01 par value, $3 per
  share redemption price, 3,300,000 shares authorized, 0, 2,662,241 and
  2,662,241 shares issued and outstanding, respectively.......................      --       7,903,833     7,912,368
                                                                                ----------  ----------  -------------
Common stockholders' equity (deficit):
  Common stock, $.01 par value, 12,000,000 shares authorized, 2,987,908,
    2,987,908 and 2,991,032 shares issued and outstanding, respectively.......      29,879      29,879        29,910
  Paid-in capital.............................................................     841,604   1,986,374     3,062,337
  Deferred compensation related to certain stock options......................      --      (1,093,779)   (1,529,773)
  Notes receivable from stock sales...........................................     (26,157)    (47,756)      (16,448)
  Accumulated deficit.........................................................  (1,519,298) (5,115,037)   (8,250,541)
                                                                                ----------  ----------  -------------
      Total common stockholders' deficit......................................    (673,972) (4,240,319)   (6,704,515)
                                                                                ----------  ----------  -------------
                                                                                $5,196,795  $10,450,504  $ 8,994,140
                                                                                ----------  ----------  -------------
                                                                                ----------  ----------  -------------
</TABLE>
 
   The accompanying notes are an integral part of these financial statements.
 
                                      F-8
<PAGE>
                             3DX TECHNOLOGIES INC.
 
                            STATEMENTS OF OPERATIONS
 
<TABLE>
<CAPTION>
                                          PERIOD FROM
                                         INCEPTION OF
                                          OPERATIONS
                                          (JANUARY 6,
                                             1993)                                        NINE MONTH PERIODS
                                            THROUGH       YEARS ENDED DECEMBER 31,       ENDED SEPTEMBER 30,
                                         DECEMBER 31,    --------------------------  ----------------------------
                                             1993           1994          1995           1995           1996
                                        ---------------  -----------  -------------  -------------  -------------
                                                                                             (UNAUDITED)
                                                                  AS RESTATED (NOTE 2)
                                        -------------------------------------------------------------------------
<S>                                     <C>              <C>          <C>            <C>            <C>
Revenues:
  Oil and gas.........................    $   --         $   303,836  $     274,511  $     202,185  $     408,459
  Rental income.......................        127,034        100,962         58,195         45,563        120,098
  Interest and other..................          7,528         52,817        236,186        125,549        217,678
                                        ---------------  -----------  -------------  -------------  -------------
      Total revenues..................        134,562        457,615        568,892        373,297        746,235
                                        ---------------  -----------  -------------  -------------  -------------
Costs and expenses:
  Lease operating.....................        --              14,225         60,877         31,443         28,463
  Production and ad valorem taxes.....        --              19,812         17,656         12,380         22,764
  Impairment of oil and gas
    properties........................        --             --           1,627,321      1,477,567      1,476,690
  Depletion, depreciation, and
    amortization......................         65,368        210,347        446,350        287,933        463,573
  General and administrative..........        596,267        598,244        905,063        652,671      1,343,660
  Interest and amortization of loan
    guarantee fees....................         88,006        --            --             --                  289
                                        ---------------  -----------  -------------  -------------  -------------
      Total costs and expenses........        749,641        842,628      3,057,267      2,461,994      3,335,439
                                        ---------------  -----------  -------------  -------------  -------------
Net loss..............................       (615,079)      (385,013)    (2,488,375)    (2,088,697)    (2,589,204)
Dividends on preferred stock..........        (52,790)      (421,696)    (1,058,956)      (113,257)      (505,167)
Accretion on preferred stock..........        (14,353)       (30,367)       (48,408)       (34,681)       (41,133)
                                        ---------------  -----------  -------------  -------------  -------------
Net loss applicable to common
  stockholders........................    $  (682,222)   $  (837,076) $  (3,595,739) $  (2,236,635) $  (3,135,504)
                                        ---------------  -----------  -------------  -------------  -------------
                                        ---------------  -----------  -------------  -------------  -------------
Pro forma net loss applicable to
  common stockholders (Note 2)
  (unaudited).........................                                $  (2,488,375)                $  (2,589,204)
                                                                      -------------                 -------------
                                                                      -------------                 -------------
Pro forma primary and fully diluted
  net loss per common share (Note 2)
  (unaudited).........................                                        $(.47)                        $(.49)
                                                                      -------------                 -------------
                                                                      -------------                 -------------
Pro forma weighted average number of
  common shares outstanding (Note 2)
  (unaudited).........................                                    5,335,982                     5,337,553
                                                                      -------------                 -------------
                                                                      -------------                 -------------
</TABLE>
 
   The accompanying notes are an integral part of these financial statements.
 
                                      F-9
<PAGE>
                             3DX TECHNOLOGIES INC.
 
         STATEMENTS OF CHANGES IN COMMON STOCKHOLDERS' EQUITY (DEFICIT)
     FOR THE PERIOD FROM INCEPTION OF OPERATIONS (JANUARY 6, 1993) THROUGH
       DECEMBER 31, 1993, AND THE YEARS ENDED DECEMBER 31, 1994 AND 1995
        AND UNAUDITED FOR THE NINE MONTH PERIOD ENDED SEPTEMBER 30, 1996
 
<TABLE>
<CAPTION>
                                                               COMMON STOCKHOLDERS' EQUITY (DEFICIT)
                                     ------------------------------------------------------------------------------------------
                                                                        AS RESTATED (NOTE 2)
                                     ------------------------------------------------------------------------------------------
                                          COMMON STOCK                                                    STOCK
                                     ----------------------   PAID-IN      DEFERRED     ACCUMULATED   SUBSCRIPTIONS
                                      SHARES      AMOUNT      CAPITAL    COMPENSATION     DEFICIT      RECEIVABLE      TOTAL
                                     ---------  -----------  ----------  -------------  ------------  -------------  ----------
<S>                                  <C>        <C>          <C>         <C>            <C>           <C>            <C>
Shares issued for cash at
  inception........................    768,117   $   7,681   $   36,891   $   --         $   --         $  --        $   44,572
Shares issued to founders in
  November 1993....................    259,172       2,592       47,538       --             --           (16,543)       33,587
Conversion of shares to common
  stock............................    329,003       3,290      419,847       --             --            --           423,137
Shares issued in November 1993.....    876,238       8,762      160,723       --             --           (24,984)      144,501
Accrual of dividends...............     --          --           --           --            (52,790)       --           (52,790)
Accretion on preferred stock.......     --          --           --           --            (14,353)       --           (14,353)
Net loss...........................     --          --           --           --           (615,079)       --          (615,079)
                                     ---------  -----------  ----------  -------------  ------------  -------------  ----------
Balance at December 31, 1993.......  2,232,530      22,325      664,999       --           (682,222)      (41,527)      (36,425)
Principal collections..............     --          --           --           --             --            27,862        27,862
Shares issued in October 1994......    755,378       7,554      176,605       --             --           (12,492)      171,667
Accrual of dividends...............     --          --           --           --           (421,696)       --          (421,696)
Accretion on preferred stock.......     --          --           --           --            (30,367)       --           (30,367)
Net loss...........................     --          --           --           --           (385,013)       --          (385,013)
                                     ---------  -----------  ----------  -------------  ------------  -------------  ----------
Balance at December 31, 1994.......  2,987,908      29,879      841,604       --         (1,519,298)      (26,157)     (673,972)
Principal collections..............     --          --           --           --             --            36,156        36,156
Shares issued in 1995..............     --          --           --           --             --           (57,755)      (57,755)
Accrual of dividends...............     --          --           --           --         (1,058,956)       --        (1,058,956)
Accretion on preferred stock.......     --          --           --           --            (48,408)       --           (48,408)
Deferred compensation related to
  certain stock options............     --          --        1,144,770    (1,144,770)       --            --            --
Compensation expense related to
  certain stock options............     --          --           --            50,991        --            --            50,991
Net loss...........................     --          --           --           --         (2,488,375)       --        (2,488,375)
                                     ---------  -----------  ----------  -------------  ------------  -------------  ----------
Balance at December 31, 1995.......  2,987,908      29,879    1,986,374    (1,093,779)   (5,115,037)      (47,756)   (4,240,319)
 
UNAUDITED:
Principal collections..............     --          --           --           --             --            31,308        31,308
Shares issued in June 1996.........      3,124          31          573       --             --            --               604
Accrual of dividends...............     --          --           --           --           (505,167)       --          (505,167)
Accretion on preferred stock.......     --          --           --           --            (41,133)       --           (41,133)
Deferred compensation related to
  certain stock options............     --          --        1,075,390    (1,075,390)       --            --            --
Compensation expense related to
  certain stock options............     --          --           --           639,396        --            --           639,396
Net loss...........................     --          --           --           --         (2,589,204)       --        (2,589,204)
                                     ---------  -----------  ----------  -------------  ------------  -------------  ----------
Balance at September 30, 1996......  2,991,032   $  29,910   $3,062,337   $(1,529,773)   $(8,250,541)   $ (16,448)   $(6,704,515)
                                     ---------  -----------  ----------  -------------  ------------  -------------  ----------
                                     ---------  -----------  ----------  -------------  ------------  -------------  ----------
</TABLE>
 
   The accompanying notes are an integral part of these financial statements.
 
                                      F-10
<PAGE>
                             3DX TECHNOLOGIES INC.
 
                            STATEMENTS OF CASH FLOWS
 
<TABLE>
<CAPTION>
                                                   PERIOD FROM
                                                   INCEPTION OF
                                                    OPERATIONS
                                                   (JANUARY 6,                             NINE MONTH PERIODS
                                                      1993)           YEARS ENDED                ENDED
                                                     THROUGH          DECEMBER 31,           SEPTEMBER 30,
                                                   DECEMBER 31,  ----------------------  ----------------------
                                                       1993         1994        1995        1995        1996
                                                   ------------  ----------  ----------  ----------  ----------
                                                                                              (UNAUDITED)
                                                                       AS RESTATED (NOTE 2)
                                                   ------------------------------------------------------------
<S>                                                <C>           <C>         <C>         <C>         <C>
CASH FLOWS FROM OPERATING ACTIVITIES:
  Net loss.......................................   $ (615,079)  $ (385,013) $(2,488,375) $(2,088,697) $(2,589,204)
  Adjustments to reconcile net loss to net cash
    provided by (used in) operating activities:
    Depletion, depreciation and amortization.....       65,368      210,347     446,350     287,933     463,573
    Compensation expense related to certain stock
      options....................................       --           --          50,991      --         639,396
    Amortization of loan guarantee fees..........       80,000       --          --          --          --
    Non-cash general and administrative
      expenses...................................       26,751       --          --          --          --
    Impairment of oil and gas properties.........       --           --       1,627,321   1,477,567   1,476,690
    (Increase) decrease in accounts receivable...     (216,147)     147,928     (45,485)     27,672    (173,844)
    (Increase) decrease in prepaid expenses......       (1,361)      (8,237)    (76,188)   (118,709)      4,452
    Increase (decrease) in accounts payable......       15,025       24,441      (3,005)   (341,112)    (72,303)
    Increase (decrease) in accrued liabilities...       26,929       26,777     (14,540)     47,641      35,717
                                                   ------------  ----------  ----------  ----------  ----------
  Net cash provided by (used in) operating
    activities...................................     (618,514)      16,243    (502,931)   (707,705)   (215,523)
                                                   ------------  ----------  ----------  ----------  ----------
CASH FLOWS FROM INVESTING ACTIVITIES:
  Acquisition, exploration and development of oil
    and gas properties...........................     (794,377)  (1,822,174) (2,185,804) (1,257,552) (2,913,619)
  Sales proceeds--undeveloped oil and gas
    interests....................................      396,370       --         480,931     480,931      --
  Purchase of technical and office equipment and
    leasehold improvements.......................       --         (108,817)   (395,093)   (104,250)   (224,479)
  Purchase of technical equipment from Landmark
    Graphics.....................................       --          (87,373)   (405,480)   (405,480)   (219,461)
  (Purchase of) proceeds from securities held to
    maturity.....................................       --           --      (1,595,167)     --       1,595,167
  Other..........................................       (2,736)         500     (12,886)     (7,886)      4,197
                                                   ------------  ----------  ----------  ----------  ----------
  Net cash used in investing activities..........     (400,743)  (2,017,864) (4,113,499) (1,294,237) (1,758,195)
                                                   ------------  ----------  ----------  ----------  ----------
CASH FLOWS FROM FINANCING ACTIVITIES:
  Common stock proceeds, net of issuance costs...      247,644      162,651      --          --             604
  Series A preferred stock cash proceeds.........      100,000       --          --          --          --
  Series B preferred stock proceeds, net of
    issuance costs...............................    2,601,875    2,352,722      25,297      25,297      --
  Series C preferred stock proceeds, net of
    issuance costs...............................       --           --       7,851,133   7,802,874      31,308
  Proceeds from issuance of long-term debt.......      400,000       --          --          --          --
  Repayments of long-term debt...................     (400,000)      --          --          --          --
                                                   ------------  ----------  ----------  ----------  ----------
  Net cash provided by financing activities......    2,949,519    2,515,373   7,876,430   7,828,171      31,912
                                                   ------------  ----------  ----------  ----------  ----------
Net change in cash and cash equivalents..........    1,930,262      513,752   3,260,000   5,826,229  (1,941,806)
Cash and cash equivalents at beginning of year...       --        1,930,262   2,444,014   2,444,014   5,704,014
                                                   ------------  ----------  ----------  ----------  ----------
Cash and cash equivalents at end of the year.....   $1,930,262   $2,444,014  $5,704,014  $8,270,243  $3,762,208
                                                   ------------  ----------  ----------  ----------  ----------
                                                   ------------  ----------  ----------  ----------  ----------
</TABLE>
 
   The accompanying notes are an integral part of these financial statements.
 
                                      F-11
<PAGE>
                             3DX TECHNOLOGIES INC.
 
                         NOTES TO FINANCIAL STATEMENTS
 
             (INFORMATION AS OF SEPTEMBER 30, 1996 AND FOR THE NINE
 
         MONTH PERIODS ENDED SEPTEMBER 30, 1995 AND 1996 IS UNAUDITED)
 
1. ORGANIZATION AND BASIS OF PRESENTATION
 
    3DX Technologies Inc. ("3DX" or the "Company"), began operations in January
1993 to offer its 3-D seismic data and computer-aided exploration capabilities
as a partner to experienced oil and gas operators in its geographical areas of
interest. By combining the operator's local knowledge and infrastructure with
3DX's imaging capabilities, 3DX believes it is able to evaluate and exploit
drilling opportunities at lower-than-normal cost. The Company primarily invests
in prospects where 3-D seismic evaluation and interpretation is expected to
reduce drilling risk. Working interests in major prospects have ranged from 5%
up to 40% in property investments to date. All of the Company's operations are
currently located in the United States. The Company's future operations are
dependent on a variety of factors, including its successful application of its
technical expertise, profitable exploitation of its oil and gas properties,
successful access to capital sources and variable oil and gas prices and costs,
among others. See "Risk Factors" included elsewhere in this document.
 
    The Company was initially funded by its three founding stockholders and by
Landmark Graphics Corporation (Landmark), a publicly-traded Houston company
which is a leading supplier of interactive computer-aided exploration systems
used by geoscientists to analyze subsurface data in the process of exploring for
and producing petroleum reserves. Landmark's initial investment included cash of
$100,000, technical equipment and office furniture valued at approximately
$150,000 and $50,000, respectively (which approximated predecessor cost),
organization costs valued at approximately $6,000, a $400,000 bank loan
guarantee valued at approximately $80,000, the payment of certain 3DX general
and administrative expenses of approximately $27,000, and preferred stock
issuance costs of approximately $87,000. The three founding stockholders of 3DX
were formerly employed by Landmark.
 
2. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES
 
    OIL AND GAS PROPERTIES
 
    3DX accounts for its oil and gas properties using the full-cost method. All
costs associated with the acquisition, exploration and development of oil and
gas properties (including such costs as leasehold acquisition costs, geological
and geophysical expenditures, dry hole costs and tangible and intangible
development costs) are capitalized as incurred. Included in capitalized costs
for the period ended December 31, 1993, the years ended December 31, 1994 and
1995 and the nine month periods ended September 30, 1995 and 1996 are general
and administrative costs of $156,652, $375,922, $618,614, $449,678, and
$649,885, respectively. Such capitalized costs include payroll and related costs
of the exploration department personnel which are directly attributable to the
Company's current acquisition, exploration and development activities. Other
costs (primarily including office rent, technical computer maintenance and
support, and communication costs) are also capitalized to the extent they are
attributed to the Company's own oil and gas property acquisition and exploration
activities and would not otherwise be incurred if such activities were not being
undertaken.
 
    Dispositions of oil and gas properties are reported as adjustments to
capitalized costs, with gains and losses not recognized unless such adjustments
would significantly alter the relationship between capitalized costs and
estimated proved oil and gas reserves.
 
                                      F-12
<PAGE>
                             3DX TECHNOLOGIES INC.
 
                   NOTES TO FINANCIAL STATEMENTS (CONTINUED)
 
             (INFORMATION AS OF SEPTEMBER 30, 1996 AND FOR THE NINE
 
         MONTH PERIODS ENDED SEPTEMBER 30, 1995 AND 1996 IS UNAUDITED)
 
2. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (CONTINUED)
    The evaluated costs of oil and gas properties plus estimated future
development and dismantlement costs (including plugging, abandonment and
site-restoration costs) are charged to operations as depreciation, depletion,
and amortization using the unit-of-production method based on the ratio of
current production to proved recoverable oil and gas reserves as estimated by
the Company and corroborated by independent petroleum engineering firms. The
Company excludes unevaluated property costs from the depreciation, depletion and
amortization computations until the discovery of proved reserves or a
determination of impairment occurs. Unevaluated properties are evaluated for
impairment on a property-by-property basis annually through 1995 and quarterly
beginning in 1996. When the determination has been made that an unproved
property has either encountered proved reserves or has been impaired, the
related costs are transferred to the evaluated cost pool which is compared in
total to the estimated values of proved reserves in the full-cost ceiling test
of asset recoverability discussed further below.
 
    Information regarding the number of, and total investment in, abandoned
projects at the time of abandonment by the Company is set forth below:
<TABLE>
<CAPTION>
                                                                         NUMBER OF      INVESTMENT IN
                                                                         PROJECTS         ABANDONED
                         ACCOUNTING PERIOD                               ABANDONED        PROJECTS
- -------------------------------------------------------------------  -----------------  -------------
<S>                                                                  <C>                <C>
Period from Inception through December 31, 1993....................              0       $         0
Year ended December 31, 1994.......................................              0                 0
Year ended December 31, 1995.......................................              3         1,173,644
 
<CAPTION>
 
                             UNAUDITED
- -------------------------------------------------------------------
<S>                                                                  <C>                <C>
Nine Months ended September 30, 1995...............................              3         1,023,889
Nine Months ended September 30, 1996...............................              2           927,366
</TABLE>
 
    Impairment of capitalized costs of oil and gas properties is determined for
each cost center, determined on a country-by-country basis. The Company's only
active cost center since inception has been the United States of America. For
each cost center, to the extent that capitalized costs of oil and gas
properties, net of related accumulated depreciation, depletion and amortization
and related deferred income taxes, exceed the discounted future net revenues of
estimated proved oil and gas reserves plus the lower of cost or fair value of
unevaluated properties, net of income tax effects, such excess costs are charged
to operations as an impairment of oil and gas properties. No such writedowns
were required during 1993 or 1994. A writedown of $1,627,321 was required for
the year ended December 31, 1995. Write-downs of $1,477,567 and $1,476,690 were
required for the nine month periods ended September 30, 1995 and 1996,
respectively.
 
    In March 1995, the Financial Accounting Standards Board issued Statement of
Financial Accounting Standard No. 121 ("SFAS No. 121") regarding accounting for
the impairment of long-lived assets. The Company adopted SFAS No. 121 effective
January 1, 1996. However, such adoption did not affect the primary test of asset
recoverability because the Company's oil and gas properties are accounted for
under the full-cost method of accounting as discussed above. The adoption of
SFAS No. 121 had no effect on the Company's results of operations for the nine
month period ended September 30, 1996.
 
    Technical interpretation equipment, including software, and office furniture
and equipment are recorded at cost. Depreciation is determined on a
straight-line basis over the estimated useful lives of the
 
                                      F-13
<PAGE>
                             3DX TECHNOLOGIES INC.
 
                   NOTES TO FINANCIAL STATEMENTS (CONTINUED)
 
             (INFORMATION AS OF SEPTEMBER 30, 1996 AND FOR THE NINE
 
         MONTH PERIODS ENDED SEPTEMBER 30, 1995 AND 1996 IS UNAUDITED)
 
2. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (CONTINUED)
assets. The estimated useful life of the technical interpretation equipment,
including software, is 3 years, and for office furniture and equipment, it is 5
years. Depletion, depreciation and amortization expense includes depreciation
related to technical interpretation equipment, including software, and office
furniture and equipment of $65,368, $119,675, $288,014, and $336,427 for the
period ended December 31, 1993, the years ended December 31, 1994 and 1995, and
the nine month period ended September 30, 1996.
 
    SECURITIES HELD TO MATURITY
 
    Securities held to maturity at December 31, 1995 include various types of
government debt securities which matured on March 31, 1996, and are carried at
amortized cost at December 31, 1995.
 
    ACCOUNTING FOR INCOME TAXES
 
    The Company provides deferred income taxes at the balance sheet date for the
estimated tax effects of differences in the existing tax basis of assets and
liabilities and their financial statement carrying amounts.
 
    NATURAL GAS REVENUES
 
    Natural gas revenues are recorded using the sales method, whereby the
Company recognizes natural gas revenues based on the amount of gas sold to
product purchasers on its behalf. The Company has no material gas imbalances.
 
    RENTAL INCOME
 
    In January 1993, the Company entered into an informal revenue-sharing
arrangement with a seismic processing company whereby the Company would receive
a percentage of the seismic processing company's gross billings in exchange for
providing office space and use of the Company's technical equipment. Revenues
under this ongoing arrangement amounted to $89,718, $100,962 and $58,195 in
1993, 1994 and 1995, respectively. Revenues under this arrangement amounted to
$45,563 and $120,098 in the nine month periods ended September 30, 1995 and
1996, respectively.
 
    STATEMENTS OF CASH FLOWS
 
    For the purposes of the statements of cash flows, the Company considers all
highly liquid investments purchased with original maturities of three months or
less to be cash equivalents.
 
    CONCENTRATION OF CREDIT RISK
 
    All of the Company's receivables are due from oil and gas producing
companies located in the United States. The Company has not experienced any
significant credit losses related to its receivables.
 
    FAIR VALUE OF FINANCIAL INSTRUMENTS
 
    The carrying amounts of cash and cash equivalents, securities held to
maturity and accounts receivable, approximate their fair values due to their
short-term nature.
 
                                      F-14
<PAGE>
                             3DX TECHNOLOGIES INC.
 
                   NOTES TO FINANCIAL STATEMENTS (CONTINUED)
 
             (INFORMATION AS OF SEPTEMBER 30, 1996 AND FOR THE NINE
 
         MONTH PERIODS ENDED SEPTEMBER 30, 1995 AND 1996 IS UNAUDITED)
 
2. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (CONTINUED)
    USE OF ESTIMATES
 
    The preparation of financial statements in conformity with generally
accepted accounting principles requires management to make estimates and
assumptions that affect the reported amounts of assets and liabilities and
disclosure of contingent assets and liabilities, if any, at the date of the
financial statements, and the reported amounts of revenues and expenses during
the reporting period. Actual results could differ from those estimates. Oil and
gas reserve estimates, which are the basis for units-of-production depletion and
the ceiling test, are inherently imprecise and are expected to change as future
information becomes available.
 
    COMPUTATION OF PRO FORMA NET LOSS APPLICABLE TO COMMON STOCKHOLDERS
     (UNAUDITED)
 
    Because of the significance of the planned redemption of Series B Preferred
Stock at its $100 liquidation value per share and conversion of a total of
2,928,465 shares of Series C Preferred Stock (which includes 266,224 shares to
be issued upon the exercise of the Series C Preferred Stock warrants at $3.00
per share) that will automatically convert into a total of 1,514,017 shares of
common stock upon effectiveness of the Offering (see Note 13), historical net
loss per common share is not presented herein. The effects of these transactions
are included in pro forma net loss applicable to common stockholders per share
for 1995 and the nine month period ended September 30, 1996 assuming such
redemption and conversion transactions occurred as of January 1, 1995. Pro Forma
net loss applicable to common stockholders is computed using the weighted
average number of common shares outstanding during the periods after giving
effect to the issuance and sale of a sufficient number of shares of common stock
in the filing of the Registration Statement on Form S-1 (Note 13) to redeem all
the issued and outstanding shares of Series B Preferred Stock and the conversion
of all Series C Preferred Stock into shares of Common Stock. All common stock
and options issued since October 18, 1995 have been, for purposes of calculating
net loss per common share, treated as outstanding for all periods presented,
which is the treatment contemplated in Staff Accounting Bulletin No. 83.
 
    INTERIM FINANCIAL DATA (UNAUDITED)
 
    The unaudited financial statements as of September 30, 1996, and for the
nine month periods ended September 30, 1995 and 1996 and all related footnote
information for these periods have been prepared on the same basis as the
audited financial statements and, in the opinion of management, include all
adjustments, consisting of normal recurring adjustments, necessary for a fair
presentation of financial position and results of operations and cash flows in
accordance with generally accepted accounting principles.
 
    PRIOR YEAR RECLASSIFICATIONS
 
    Certain prior year amounts have been reclassified to conform with the
current presentation.
 
                                      F-15
<PAGE>
                             3DX TECHNOLOGIES INC.
 
                   NOTES TO FINANCIAL STATEMENTS (CONTINUED)
 
             (INFORMATION AS OF SEPTEMBER 30, 1996 AND FOR THE NINE
 
         MONTH PERIODS ENDED SEPTEMBER 30, 1995 AND 1996 IS UNAUDITED)
 
2. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (CONTINUED)
FINANCIAL STATEMENT ADJUSTMENTS
 
    Since the initial filing of the Registration Statement of which this
Prospectus forms a part (see Note 13), the Company has made certain changes to
its prior period financial statements. These changes have included:
 
    - Accrual of $51,000 of option compensation in 1995 and $639,000 in the
      nine-month period ended September 30, 1996 (see Note 7) primarily to
      reflect the estimated intrinsic value of such option grants using the
      assumed initial public offering price of Common Stock as the estimate of
      fair value
 
    - Changes in the accrual of preferred stock dividends (Series A Preferred
      Stock and Series C Preferred Stock) to reflect their constructively
      cumulative nature (see Note 5)
 
    - Refinements in the valuation, and related accretion, of preferred stock,
      to report such amounts at more precise estimates of fair values when
      issued (see Note 5)
 
    The effects of these changes (none of which affected income tax amounts) on
previously reported financial statement items are as follows:
 
<TABLE>
<CAPTION>
                                                                                                     NINE MONTH
                                                              FOR THE YEAR ENDED DECEMBER 31,       PERIOD ENDED
                                                         -----------------------------------------  SEPTEMBER 30,
                                                            1993          1994           1995           1996
                                                         -----------  -------------  -------------  -------------
<S>                                                      <C>          <C>            <C>            <C>
Net loss:
  As originally reported...............................  $  (615,079) $    (385,013) $  (2,437,384)  $(1,949,808)
  Accrue option compensation...........................      --            --              (50,991)     (639,396)
                                                         -----------  -------------  -------------  -------------
  As currently reported................................  $  (615,079) $    (385,013) $  (2,488,375)  $(2,589,204)
                                                         -----------  -------------  -------------  -------------
                                                         -----------  -------------  -------------  -------------
Net loss to common stockholders:
  As originally reported...............................  $  (619,045) $    (918,780) $  (3,269,492)  $(2,789,613)
  Accrue option compensation...........................      --            --              (50,991)     (639,396)
  Change dividend accrual..............................      (52,790)        81,704       (275,256)      293,505
  Adjust preferred stock valuation and accretion.......      (10,387)      --             --             --
                                                         -----------  -------------  -------------  -------------
  As currently reported................................  $  (682,222) $    (837,076) $  (3,595,739)  $(3,135,504)
                                                         -----------  -------------  -------------  -------------
                                                         -----------  -------------  -------------  -------------
Pro Forma net loss per share:
  As originally reported...............................      N/A           N/A       $       (0.49)  $     (0.39)
  Accrue option compensation...........................                                       (.01)         (.12)
  Change dividend accrual..............................                                   --             --
  Change in pro forma common shares outstanding........                                        .03           .02
                                                                                     -------------  -------------
  As currently reported................................                              $        (.47)  $      (.49)
                                                                                     -------------  -------------
                                                                                     -------------  -------------
</TABLE>
 
                                      F-16
<PAGE>
                             3DX TECHNOLOGIES INC.
 
                   NOTES TO FINANCIAL STATEMENTS (CONTINUED)
 
             (INFORMATION AS OF SEPTEMBER 30, 1996 AND FOR THE NINE
 
         MONTH PERIODS ENDED SEPTEMBER 30, 1995 AND 1996 IS UNAUDITED)
 
2. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (CONTINUED)
 
<TABLE>
<CAPTION>
                                                                                                     NINE MONTH
                                                              FOR THE YEAR ENDED DECEMBER 31,       PERIOD ENDED
                                                         -----------------------------------------  SEPTEMBER 30,
                                                            1993          1994           1995           1996
                                                         -----------  -------------  -------------  -------------
Accumulated deficit:
<S>                                                      <C>          <C>            <C>            <C>
  As originally reported...............................  $  (619,045) $  (1,537,825) $  (4,807,317)  $(7,596,930)
  Accrue option compensation...........................      --            --              (50,991)     (690,387)
  Change dividend accrual..............................      (52,790)        28,914       (246,342)       47,163
  Adjust preferred stock valuation and accretion.......      (10,387)       (10,387)       (10,387)      (10,387)
                                                         -----------  -------------  -------------  -------------
  As currently reported................................  $  (682,222) $  (1,519,298) $  (5,115,037)  $(8,250,541)
                                                         -----------  -------------  -------------  -------------
                                                         -----------  -------------  -------------  -------------
Common stockholders' equity (deficit):
  As originally reported...............................  $    16,365  $    (740,937) $  (4,032,028)  $(6,789,729)
  Change dividend accrual..............................      (52,790)      --             (208,291)       85,214
  Adjust preferred stock valuation and accretion.......                      66,965       --             --
                                                         -----------  -------------  -------------  -------------
  As currently reported................................  $   (36,425) $    (673,972) $  (4,240,319)  $(6,704,515)
                                                         -----------  -------------  -------------  -------------
                                                         -----------  -------------  -------------  -------------
</TABLE>
 
3. INCOME TAXES
 
    Significant components of the Company's deferred tax liabilities and assets
are as follows:
 
<TABLE>
<CAPTION>
                                                                           DECEMBER 31,
                                                                    --------------------------
                                                                       1994          1995
                                                                    -----------  -------------
<S>                                                                 <C>          <C>
Deferred tax liability:
  Exploration and development expenditures deducted for tax and
    capitalized for books.........................................  $   345,831  $    (103,867)
  Other items, net................................................      --             (37,523)
                                                                    -----------  -------------
      Total deferred tax liability................................     (345,831)      (141,390)
                                                                    -----------  -------------
Deferred tax assets:
  Net operating loss carryforwards................................      653,394      1,238,317
  Other items, net................................................       28,419         66,375
                                                                    -----------  -------------
      Total deferred tax assets...................................      681,813      1,304,692
  Less: Valuation allowance.......................................     (335,982)    (1,163,302)
                                                                    -----------  -------------
Net deferred tax assets...........................................      345,831        141,390
                                                                    -----------  -------------
Net deferred tax liability........................................  $   --       $    --
                                                                    -----------  -------------
                                                                    -----------  -------------
</TABLE>
 
    The Company did not record any current or deferred income tax provision or
benefit in any of the periods presented. The Company's provision for income
taxes differs from the amount computed by applying the statutory rate due
principally to the valuation allowance recorded against its deferred tax asset
account relating to net operating tax loss carryforwards. Management believes
that such allowance is necessary until there is greater assurance that the net
operating tax loss carryforwards can be utilized.
 
                                      F-17
<PAGE>
                             3DX TECHNOLOGIES INC.
 
                   NOTES TO FINANCIAL STATEMENTS (CONTINUED)
 
             (INFORMATION AS OF SEPTEMBER 30, 1996 AND FOR THE NINE
 
         MONTH PERIODS ENDED SEPTEMBER 30, 1995 AND 1996 IS UNAUDITED)
 
3. INCOME TAXES (CONTINUED)
    The Company has recorded a valuation allowance against its deferred tax
assets in each year to reflect the estimated portion for which realization is
uncertain. Such valuation allowance amounted to $208,183, $335,982 and
$1,163,302 as of December 31, 1993, 1994 and 1995 respectively. As of December
31, 1995, the Company has tax net operating loss carryforwards of $3,642,108
which begin to expire in 2008. As a result of the pending initial public
offering (See Note 13), there may be a limitation placed on the Company's
utilization of its NOL's by Section 382 of the Internal Revenue Code. The
Company will review the valuation allowance at the end of each quarter and will
make adjustments if it is determined that it is more likely than not that the
deferred tax assets will be realized.
 
4. RELATED-PARTY TRANSACTIONS
 
    The Company purchased technical equipment, supplies, and software and
hardware maintenance amounting to $174,374 in 1993, $118,630 in 1994 and
$521,128 in 1995 from Landmark. During the unaudited nine month periods ended
September 30, 1995 and 1996, the Company purchased $405,480 and $219,461,
respectively, from Landmark.
 
5. MANDATORILY REDEEMABLE PREFERRED STOCK
 
    On January 27, 1993, the Company sold 100,000 shares of Series A preferred
stock to Landmark for a total consideration of $500,000, composed of cash,
technical and office equipment, furniture, organizational costs, a bank loan
guarantee, payment of certain general and administrative expenses, and preferred
stock issuance costs. The Series A preferred stock contained no voting rights,
was convertible into 517,000 shares of Class A common stock, contained a
mandatory-redemption feature which allowed the holder of the Series A preferred
stock to require 3DX to redeem the stock at the higher of the original issue
value or the then-current fair market value of the stock at the time of
redemption, and was entitled to receive, when, as and if declared by the Board
of Directors, dividends in cash at the annual rate of $.50 per share, payable
quarterly and senior in ranking to any common stock dividends. Until January 1,
1998, the right to dividends upon the issued and outstanding shares of Series A
preferred stock were non-cumulative and were not deemed to accrue unless and
until said dividends were declared by the Board. From and after January 1, 1998,
the right to dividends upon the issued and outstanding shares of Series A
preferred stock were cumulative. The Series A preferred stock held preferential
liquidation rights for $5 per share plus any dividends payable at the date of
liquidation, and also contained an automatic conversion provision in the event
of an initial public offering.
 
    In connection with the sale of equity units in November 1993, Landmark
agreed to exchange the shares of Series A preferred stock into 329,003 shares of
common stock. Landmark agreed to accept such number of shares in exchange for a
release of its guarantee of certain bank indebtedness of the Company.
 
    The Company's Series B and Series C redeemable preferred stocks described
below are presented on the balance sheet outside of common equity because they
both have mandatory-redemption provisions outside the control of the Company,
and both are being accreted to their projected redemption values through a
charge to common equity during the periods such securities were outstanding.
 
    In November 1993, the Company negotiated an agreement pursuant to which
certain investors agreed to purchase 54,000 units (each unit consisting of one
share of redeemable Series B preferred stock and
 
                                      F-18
<PAGE>
                             3DX TECHNOLOGIES INC.
 
                   NOTES TO FINANCIAL STATEMENTS (CONTINUED)
 
             (INFORMATION AS OF SEPTEMBER 30, 1996 AND FOR THE NINE
 
         MONTH PERIODS ENDED SEPTEMBER 30, 1995 AND 1996 IS UNAUDITED)
 
5. MANDATORILY REDEEMABLE PREFERRED STOCK (CONTINUED)
30.215 shares of common stock) for total consideration in the amount of
$5,400,000. The sales of the units was timed to be funded in two traunches to
match the projected cash flow needs of the Company, with the first traunch
(consisting of 29,000 units) funded in November 1993 and the second traunch
(consisting of 25,000 units) funded in October 1994. The terms of the agreement
provided a substantial penalty for any investor who committed to purchase units
in the second traunch and failed to do so. All investors who committed to
purchase units in the second traunch did so in October 1994. Sales of the 54,000
units were as follows: 4,500 units were sold to members of management (8.3% of
the total units sold), 4,000 units were sold to Landmark (7.4% of the total
units sold), 1,750 units were sold to Consultants to the Company (3.2% of the
total units sold), 28,820 units were sold to two investment funds (18,820 units
to Citi Growth Fund L.P. and 10,000 units to R. Chaney & Partners - 1993 L.P.)
whose purchases were conditioned on the ability of each investor group to
designate one member of the Board of Directors (53.4% of the total units sold),
1,500 units were sold to one investor-designated member and one future member of
the Board of Directors (2.8% of the total units sold), and the remaining 13,430
units were sold to other unrelated investors (24.9% of the total units sold).
 
    In November 1993, the Company sold 29,000 equity units consisting of an
aggregate of 29,000 shares of the Company's redeemable Series B preferred stock,
par value of $.01 per share, and 876,237 shares of common stock, par value of
$.01 per share. The stock was sold for net proceeds of $94.1558 per share of
Series B preferred stock and $.19 per share of common stock. The difference
between the sales price and the redemption price of $100 per share is subject to
an annual pro-rata accretion charge to retained earnings, so that at the time of
the mandatory redemption, the value of each share of preferred stock will equal
the redemption price of $100. The Series B preferred stockholders are entitled
to 100 votes for each share held, and shall vote together with holders of common
stock and not as a separate class. The Series B preferred stockholders are
entitled to receive (out of any funds legally available therefor) dividends (in
cash or in shares of Series B preferred stock, as determined by the Board of
Directors) at an annual rate per share of $12.50 if in cash or .13276 shares of
Series B preferred stock if in stock, payable annually on December 31,
commencing in December 1994. In the event the Board of Directors fails to
declare the dividend in stock or cash ten working days prior to the end of each
year, the dividend is deemed declared in stock as of the end of the year. As a
result, the dividend is constructively cumulative. The Series B preferred stock
has a redemption price of $100 per share. The Series B preferred stock also
contains a mandatory-redemption feature under which the stock will be redeemed
at the redemption price in two installments (50% on November 9, 2002 and 50% on
November 9, 2003). 3DX has the option to redeem the outstanding Series B
Preferred stock at any time with funds legally available therefor. As
consideration for the Series B preferred and common stock sale, the Company
received $2,875,019 in cash and promissory notes from two of its founders
amounting to $24,984. The Company incurred legal and other offering costs of
$103,659 in connection with this Series B preferred stock unit sale.
 
    On October 24, 1994, the Company sold 25,000 equity units consisting of an
aggregate of 25,000 shares of the Company's redeemable Series B preferred stock,
par value of $.01 per share, and 755,378 shares of common stock, par value of
$.01 per share. The stock was sold for net proceeds of $94.1558 per share of
Series B preferred stock and $.19 per share of common stock. As consideration
for the Series B preferred and common stock sale, the Company received
$2,487,511 in cash and a promissory note from one of its founders amounting to
$12,492.
 
                                      F-19
<PAGE>
                             3DX TECHNOLOGIES INC.
 
                   NOTES TO FINANCIAL STATEMENTS (CONTINUED)
 
             (INFORMATION AS OF SEPTEMBER 30, 1996 AND FOR THE NINE
 
         MONTH PERIODS ENDED SEPTEMBER 30, 1995 AND 1996 IS UNAUDITED)
 
5. MANDATORILY REDEEMABLE PREFERRED STOCK (CONTINUED)
    Dividends on the Series B preferred stock have been paid in stock rather
than in cash as determined by the Board of Directors.
 
    During the period from July 26, 1995 until September 25, 1995, the Company
sold a total of 2,662,241 shares of the Company's senior redeemable convertible
Series C preferred stock, par value of $.01 per share. The stock was sold for $3
per share. Purchasers of the 2,662,241 shares of Series C Preferred Stock
consisted of members of management who purchased 89,237 shares (3.4% of the
total Series C shares sold), consultants to the Company who purchased 17,134
shares (0.6% of the total Series C shares sold), two members of the Board of
Directors who purchased 10,000 shares (0.4% of the total Series C shares sold),
other previous Series B unit investors who purchased 329,203 shares (including
125,467 shares purchased by Citi Growth Fund L.P. and 66,667 shares by R. Chaney
& Partners - 1993 L.P.) (12.3% of the total Series C shares sold), NationsBank
Capital Corporation whose purchase of 1,333,333 shares was conditioned on its
ability to designate a member of the Company's Board of Directors (50.1% of the
total Series C shares sold), and the remaining 883,334 shares were sold to other
unaffiliated investors (33.2% of the total Series C shares sold). The Series C
preferred stockholders are entitled to 1 vote for each number of common shares
their Series C preferred stock is convertible into, and shall vote together with
holders of common stock and not as a separate class. The Series C preferred
stockholders are entitled to receive when, as and if declared by the Board of
Directors (out of any funds legally available therefor) dividends (in cash or in
shares of Series C preferred stock, as determined by the Board of Directors) at
an annual rate per share of $.24 if in cash or .08 shares of Series C preferred
stock if in stock, payable or accruing quarterly, commencing on September 30,
1995. If dividends are accrued, the unpaid dividends compound at an annual
interest rate of 8%. In the event the Board of Directors fails to declare the
dividend in stock or cash ten working days prior to the end of each calendar
quarter, the dividend is automatically deemed declared in cash as of the end of
the quarter. As a result the dividend is constructively cumulative.
 
    The Series C preferred stock also contains a right to convert to common
stock on a one share for one share basis at any time (See Note 13 for discussion
of the impact of the October 1996 reverse stock split), and the shares shall be
automatically converted upon the occurrence of certain automatic conversion
events (including the successful completion of an initial public offering of the
Company's common stock if certain pricing and other criteria are met). The
Series C preferred stock also contains a mandatory-redemption feature under
which the stock will be redeemed (if requested in writing with at least 30 days
notice by at least 67% of the holders) at the liquidation price in two
installments (50% on November 9, 2002 and 50% on November 9, 2003). In the event
of a merger, sale or dissolution of the Company, or initiation of mandatory
redemption of the senior preferred Series C stock where the proceeds to the
holders are less than two times the holders' original basis plus accrued
dividends, then in such event the holders will receive the face value of their
investment plus accrued dividends and will also be entitled to participate on an
"as if converted" basis in all remaining net proceeds of the Company. As
consideration for the Series C preferred stock sale, the Company received
$7,928,968 in cash, and promissory notes from two of its founders and one board
member amounting to $57,755. The Company incurred legal and other offering costs
of $87,834 in connection with this Series C preferred stock sale.
 
    At its October 6, 1995 meeting, the Board of Directors of the Company
granted each purchaser of shares of senior redeemable convertible Series C
preferred stock a warrant to purchase additional shares equal to 10% of the
shares owned by such purchaser, at an exercise price of $3 per share, such
shares to be
 
                                      F-20
<PAGE>
                             3DX TECHNOLOGIES INC.
 
                   NOTES TO FINANCIAL STATEMENTS (CONTINUED)
 
             (INFORMATION AS OF SEPTEMBER 30, 1996 AND FOR THE NINE
 
         MONTH PERIODS ENDED SEPTEMBER 30, 1995 AND 1996 IS UNAUDITED)
 
5. MANDATORILY REDEEMABLE PREFERRED STOCK (CONTINUED)
exercisable at any time until the earlier of (a) five years from the date of
issuance and (b) the effective date of an initial public offering of the
Company's securities. No value was assigned to these warrants as the computed
value of the warrants using the Black-Scholes model was zero.
 
    During the nine months ended September 30, 1996, the Company accrued a
dividend on the Series C preferred stock of $505,167.
 
    The following table summarizes the inception to date activity of mandatorily
redeemable preferred stock:
 
<TABLE>
<CAPTION>
                                                                      REDEEMABLE PREFERRED STOCK
                                              --------------------------------------------------------------------------
                                                     SERIES A                 SERIES B                  SERIES C
                                              -----------------------  -----------------------  ------------------------
                                                SHARES      AMOUNT      SHARES       AMOUNT       SHARES       AMOUNT
                                              ----------  -----------  ---------  ------------  ----------  ------------
<S>                                           <C>         <C>          <C>        <C>           <C>         <C>
Shares issued for cash and other assets in
  January 1993..............................     100,000  $   500,000     --      $    --           --      $    --
Issuance costs..............................      --          (87,250)    --           --           --           --
Conversion of shares to common stock........    (100,000)    (423,137)    --           --           --           --
Shares issued in November 1993..............      --          --          29,000     2,730,518      --           --
Issuance costs..............................      --          --          --          (103,659)     --           --
Accrual of dividends........................      --          --             560        52,790
Accretion to redemption value...............      --           10,387     --             3,966      --           --
                                              ----------  -----------  ---------  ------------  ----------  ------------
Balance at December 31, 1993................      --          --          29,560     2,683,615      --           --
Shares issued in October 1994...............      --          --          25,000     2,315,844      --           --
Accrual of dividends........................      --          --           4,474       421,696      --           --
Accretion to redemption value...............      --          --          --            30,367      --           --
                                              ----------  -----------  ---------  ------------  ----------  ------------
Balance at December 31, 1994................      --          --          59,034     5,451,522      --           --
Shares issued in 1995.......................      --          --          --           --        2,662,241     7,986,723
Issuance costs..............................      --                                      (860)     --           (87,834)
Accrual of dividends........................      --          --           7,837       783,700      --           --
Accretion to redemption value...............      --          --          --            43,464      --             4,944
                                              ----------  -----------  ---------  ------------  ----------  ------------
Balance at December 31, 1995................      --          --          66,871     6,277,826   2,662,241     7,903,833
 
UNAUDITED:
Accretion to redemption value...............      --          --          --            32,598      --             8,535
                                              ----------  -----------  ---------  ------------  ----------  ------------
Balance of September 30, 1996...............      --      $   --          66,871  $  6,310,424   2,662,241  $  7,912,368
                                              ----------  -----------  ---------  ------------  ----------  ------------
                                              ----------  -----------  ---------  ------------  ----------  ------------
</TABLE>
 
6. COMMON STOCKHOLDERS' EQUITY (DEFICIT)
 
    On January 27, 1993, the Company sold 768,117 shares of common stock to its
founding stockholders for $44,572 ($.06 per share). These shares are subject to
a stock purchase and restriction agreement under which the Company has retained
a right to repurchase any "unvested" shares at the original sales price of $.06
per share. For purposes of determining vesting, the shares vest over a period of
4 years based on the
 
                                      F-21
<PAGE>
                             3DX TECHNOLOGIES INC.
 
                   NOTES TO FINANCIAL STATEMENTS (CONTINUED)
 
             (INFORMATION AS OF SEPTEMBER 30, 1996 AND FOR THE NINE
 
         MONTH PERIODS ENDED SEPTEMBER 30, 1995 AND 1996 IS UNAUDITED)
 
6. COMMON STOCKHOLDERS' EQUITY (DEFICIT) (CONTINUED)
continued employment of the applicable stockholder, annually the first two years
and monthly the next 24 months.
 
    On November 9, 1993, the Company sold 259,172 shares of common stock to its
founding stockholders at $.19 per share. As consideration for the common stock
sale, the Company received net proceeds of $33,587 in cash and a promissory note
from one of its founders amounting to $16,543.
 
    On May 24, 1995, the stockholders approved a 10-for-1 stock split of the
Company's common stock. See also Note 12 for information on the reverse stock
split which occurred in October 1996. All references in this report to the
number of common shares outstanding reflect these splits.
 
7. STOCK OPTIONS
 
    In June 1994, the Board of Directors approved the 1994 Stock Option Plan
(the Plan) for employees, officers, directors and certain consultants of the
Company. The ten year options vest for employees over four years (annually for
the first two years and monthly the last two years) and for directors and
consultants over three years (annually with 50% in year one) and certain of
these options are eligible for accelerated vesting upon a change of control of
the Company. At December 31, 1995 the Company had reserved 987,937 shares of
common stock for issuance under this Plan.
 
    The following table summarizes option balances and activity for the Plan:
 
<TABLE>
<CAPTION>
                                                                                YEAR ENDED
                                                                               DECEMBER 31,
                                                                         ------------------------
                                                                            1994         1995
                                                                         -----------  -----------  PERIOD ENDED
                                                                                                   SEPTEMBER 30,
                                                                                                       1996
                                                                                                   -------------
                                                                                                    (UNAUDITED)
<S>                                                                      <C>          <C>          <C>
Option shares outstanding:
  Beginning of period..................................................      --           438,783       686,943
  Granted..............................................................      438,783      248,160       235,235
  Exercised............................................................      --           --             (3,124)
  Canceled.............................................................      --           --           (157,146)
                                                                         -----------  -----------  -------------
  End of period........................................................      438,783      686,943       761,908
Shares available for grant at end of period............................      549,154      300,994       222,905
Weighted average price of options exercised during period..............      --           --        $      0.19
Range of exercise price of options outstanding at end of period........  $ 0.19-0.26  $ 0.19-0.58   $ 0.19-0.58
Weighted average exercise price of options outstanding at end of
  period...............................................................  $      0.22  $      0.42   $      0.47
Weighted average fair value of options granted during period...........      --       $      4.75   $     13.55
</TABLE>
 
    Prior to the fourth quarter of 1995, the Company did not record any
compensation expense related to the above options because the related exercise
prices were at or above the estimated fair values of the Company's common stock
at the time such options were granted. In connection with stock options granted
within one year of the initial filing of the Form S-1 registration statement of
which this Prospectus forms a part (see Note 13), the Company has recorded
deferred compensation as additional paid in capital and an offsetting
contra-equity account. Such compensation accrual is based on the difference
between the option price and the fair value of the Company's common stock when
such options are granted (using the initial
 
                                      F-22
<PAGE>
                             3DX TECHNOLOGIES INC.
 
                   NOTES TO FINANCIAL STATEMENTS (CONTINUED)
 
             (INFORMATION AS OF SEPTEMBER 30, 1996 AND FOR THE NINE
 
         MONTH PERIODS ENDED SEPTEMBER 30, 1995 AND 1996 IS UNAUDITED)
 
7. STOCK OPTIONS (CONTINUED)
$14.00 per share estimate of the initial public offering common stock price as
an estimate of fair value). Such deferred compensation is recorded as general
and administrative expenses over the period underlying the options become
vested, which resulted in $51,000 and $639,000 of expenses in 1995 and the
nine-month period ended September 30, 1996, respectively. Had the Company used
the actual offering price of $11.00 per share to compute the deferred
compensation resulting from the difference between such option exercise prices
and the fair value of the Company's common stock, the September 30, 1996
financial statements would reflect the following reductions:
 
<TABLE>
<CAPTION>
Deferred compensation related to stock options....................  $ 341,983
<S>                                                                 <C>
Paid-in capital                                                       496,320
Accumulated deficit & Net loss....................................  $ 154,337
</TABLE>
 
    In October 1995, the Financial Accounting Standards Board issued Statement
No. 123 ("SFAS No. 123"). SFAS No. 123 is a new standard of accounting for
stock-based compensation and establishes a fair value method of accounting for
awards granted after December 31, 1995 under stock compensation plans. SFAS No.
123 encourages, but does not require, companies to adopt the fair value method
of accounting in place of the existing method of accounting for stock-based
compensation for employees whereupon compensation costs are recognized only in
situations where stock compensation plans award intrinsic value to recipients at
the date of grant. Companies that do not adopt the fair value method of
accounting prescribed in SFAS No. 123 must, nonetheless, make annual pro forma
disclosures of the estimated effects on net income and earnings per share in
their year-end 1996 financial statements as if the fair value method had been
used for grants after December 31, 1994. The 5,170 options granted to persons
other than employees during the first nine months of 1996 had fair values which
approximated the intrinsic values computed as described in the previous
paragraph and the related compensation accruals under the two methods were
therefore about equal.
 
8. NOTES RECEIVABLE FROM STOCK SALES
 
    During 1993, 1994 and 1995, two officers and one member of the Board of
Directors purchased common or preferred stock for notes, which are reflected as
an offset to equity in the accompanying financial statements. The notes are full
recourse promissory notes bearing interest at a fixed rate of 6% per annum. The
notes from the two employees are collateralized by certain vested stock options
the individuals hold from their former employer. The principal and all accrued
interest on the notes held at December 31, 1995 and at September 30, 1996 are
due in or before January 1997.
 
9. SAVINGS PLAN
 
    The Company has joined with Landmark in offering its employees an employee
401-K savings plan (the Plan) which became effective upon inception of the
Company. The Plan covers substantially all employees and entitles them to
contribute up to 15% of their annual compensation, subject to maximum
limitations imposed by the Internal Revenue Code. While the Plan allows for
employer matching of a portion of the employee contributions, the Company has
elected not to match contributions.
 
                                      F-23
<PAGE>
                             3DX TECHNOLOGIES INC.
 
                   NOTES TO FINANCIAL STATEMENTS (CONTINUED)
 
             (INFORMATION AS OF SEPTEMBER 30, 1996 AND FOR THE NINE
 
         MONTH PERIODS ENDED SEPTEMBER 30, 1995 AND 1996 IS UNAUDITED)
 
10. COMMITMENTS
 
    Effective March 1, 1995, the Company entered into a 5-year office facilities
operating lease agreement which required an 18-month rent prepayment at
inception, and contains typical renewal options and escalation clauses. Rental
expense under office facilities operating leases was approximately $61,000 in
1994 and $90,370 in 1995. Rental expense under office facilities operating
leases was $66,599 and $72,136 for the nine months ended September 30, 1995 and
1996, respectively.
 
    Future minimum payments under non-cancelable operating leases having initial
terms of one year or more are as follows at December 31, 1995:
 
<TABLE>
<S>                                                         <C>
  1996....................................................  $  31,544
  1997....................................................     94,633
  1998....................................................     94,633
  1999....................................................     94,633
  Thereafter..............................................     15,772
                                                            ---------
Total minimum lease payments..............................  $ 331,215
                                                            ---------
                                                            ---------
</TABLE>
 
11. SALE OF ASSETS
 
    In April 1995, the Company sold 66.67% of its working interest in the Double
Diamond/Jones Ranch prospect to a group of individual investors who are
stockholders in the Company (through a limited partnership). Proceeds from the
sale, which represented both the estimated fair market value of the interest
sold as well as 3DX's proportionate cost to date on the prospect, amounted to
$480,931. No gain or loss was recorded on this transaction.
 
                                      F-24
<PAGE>
                             3DX TECHNOLOGIES INC.
 
                   NOTES TO FINANCIAL STATEMENTS (CONTINUED)
 
             (INFORMATION AS OF SEPTEMBER 30, 1996 AND FOR THE NINE
 
         MONTH PERIODS ENDED SEPTEMBER 30, 1995 AND 1996 IS UNAUDITED)
 
12. SUPPLEMENTAL CASH FLOW INFORMATION
 
    The following table summarizes cash paid for interest and taxes as well as
non-cash transactions for the indicated periods:
<TABLE>
<CAPTION>
                                                                                            SEPT. 30,  SEPT. 30,
                                                           1993        1994        1995       1995        1996
                                                        ----------  ----------  ----------  ---------  ----------
<S>                                                     <C>         <C>         <C>         <C>        <C>
Cash paid during period for interest..................  $    8,006  $   --      $   --      $  --      $      289
Cash paid during period for taxes.....................      --          --          --         --          --
 
<CAPTION>
 
NON-CASH TRANSACTIONS:
<S>                                                     <C>         <C>         <C>         <C>        <C>
Dividends declared but not paid.......................  $       --  $       --  $  275,256  $      --  $  505,167
Accretion on preferred stock..........................      14,353      30,367      48,408     34,681      41,133
Sale of Series A preferred stock to Landmark in
  exchange for technical & office equipment,
  furniture, organizational costs, bank loan
  guarantee, payment of certain general &
  administrative expenses and preferred stock issuance
  costs...............................................     400,000      --          --         --          --
Exchange of Series A preferred stock for 329,003
  shares of common stock..............................     412,750      --          --         --          --
Sale of common stock in exchange for promissory note
  from one of the founders............................      16,543      --          --         --          --
Sale of common stock in exchange for promissory note
  from one of the founders (November 1993)............      24,984      --          --         --          --
Sale of Series B preferred and common stock in
  exchange for promissory note from one of the
  founders (October 24, 1994).........................      --          12,492      --         --          --
Stock dividend on Series B preferred stock............      52,790     421,699     783,700     --          --
Sale of Series C preferred stock in exchange for
  promissory notes from two of the founders...........      --          --          57,755     --          --
10 for 1 common stock split (Note 13).................      --          --          --         --          --
</TABLE>
 
13. EVENTS SUBSEQUENT TO AUDITORS' REPORT DATE
 
    In October 1996, the Board of Directors authorized a reverse stock split
whereby stockholders of common stock will receive .517 shares of common stock
for every 1 share previously owned. The previous conversion ratio of 1 share of
Series C Preferred Stock for 1 share of Common Stock will also be adjusted for
this reverse split so that 1 share of Series C Preferred Stock will be
convertible into .517 shares of common stock. In addition, authorized, issued,
and outstanding options under the Company's 1994 stock option plan will be
revised to reflect the impact of the reverse stock split on share and option
prices. All references in this report to number of common shares outstanding
reflect this reverse stock split retroactively to inception of the Company.
 
    The Company filed a registration statement on Form S-1 for the sale of
2,400,000 shares of common stock which became effective on December 19, 1996.
The offering is expected to raise approximately $23.8
 
                                      F-25
<PAGE>
                             3DX TECHNOLOGIES INC.
 
                   NOTES TO FINANCIAL STATEMENTS (CONTINUED)
 
             (INFORMATION AS OF SEPTEMBER 30, 1996 AND FOR THE NINE
 
         MONTH PERIODS ENDED SEPTEMBER 30, 1995 AND 1996 IS UNAUDITED)
 
13. EVENTS SUBSEQUENT TO AUDITORS' REPORT DATE (CONTINUED)
million in net proceeds, which are expected to be used, among other purposes, to
redeem all the outstanding Series B preferred stock and for future capital and
exploration expenditures. In connection with such offering, the Series C
preferred stock is expected to be converted to common stock and the Series C
dividends payable will be paid in cash.
 
14. RESULTS OF OPERATIONS FOR OIL AND GAS PRODUCING ACTIVITIES (UNAUDITED)
 
    The following table sets forth the Company's results of operations for oil
and gas producing activities for the years ended December 31, 1994 and 1995 and
for the nine months ended September 30, 1996. There were no oil and gas
producing activities for the period from inception (January 6, 1993) through
December 31, 1993.
 
<TABLE>
<CAPTION>
                                                                                           SEPTEMBER 30,
                                                                   1994         1995           1996
                                                                ----------  -------------  -------------
<S>                                                             <C>         <C>            <C>
Oil and gas revenues..........................................  $  303,836  $     274,511   $   408,459
Lease operating costs.........................................      14,225         60,877        28,463
Production taxes..............................................      19,812         17,656        22,764
Impairment of oil and gas properties..........................      --          1,627,321     1,476,690
Depletion, depreciation and amortization......................      90,672        158,336       126,342
                                                                ----------  -------------  -------------
Income (loss) before income taxes.............................     179,127     (1,589,679)   (1,245,800)
Income tax expense (credit)...................................      --           --             --
                                                                ----------  -------------  -------------
Net income (loss).............................................  $  179,127  $  (1,589,679)  $(1,245,800)
                                                                ----------  -------------  -------------
                                                                ----------  -------------  -------------
Amortization per physical unit of production (equivalent Mcf
  of gas).....................................................  $      .64  $        1.15   $       .81
                                                                ----------  -------------  -------------
</TABLE>
 
    The results of operations from oil and gas producing activities were
determined in accordance with Statement of Financial Accounting Standards No.
69, "Disclosures About Oil and Gas Producing Activities" ("SFAS No. 69") and,
therefore, do not include corporate overhead, interest and other general income
and expense items.
 
15. COSTS RELATING TO OIL AND GAS PRODUCING ACTIVITIES (UNAUDITED)
 
    The aggregate amounts of capitalized costs relating to the Company's oil and
gas producing activities and the related accumulated depletion, depreciation,
and amortization and impairment at December 31, 1994 and 1995 and at September
30, 1996 were as follows:
 
<TABLE>
<CAPTION>
                                                                  1994          1995           1996
                                                              ------------  -------------  -------------
<S>                                                           <C>           <C>            <C>
Unproved properties.........................................  $    828,321  $   1,375,145  $   1,993,753
Proved properties...........................................     1,575,146      2,648,724      5,441,851
                                                              ------------  -------------  -------------
Total capitalized costs.....................................     2,403,467      4,023,869      7,435,604
Less--accumulated depletion, depreciation and
  amortization..............................................       (90,672)    (1,876,329)    (3,479,361)
                                                              ------------  -------------  -------------
                                                              $  2,312,795  $   2,147,540  $   3,956,243
                                                              ------------  -------------  -------------
                                                              ------------  -------------  -------------
</TABLE>
 
                                      F-26
<PAGE>
                             3DX TECHNOLOGIES INC.
 
                   NOTES TO FINANCIAL STATEMENTS (CONTINUED)
 
             (INFORMATION AS OF SEPTEMBER 30, 1996 AND FOR THE NINE
 
         MONTH PERIODS ENDED SEPTEMBER 30, 1995 AND 1996 IS UNAUDITED)
 
15. COSTS RELATING TO OIL AND GAS PRODUCING ACTIVITIES (UNAUDITED) (CONTINUED)
    Unevaluated properties and associated costs not currently being amortized
and included in oil and gas properties were $828,321, $1,375,145, and $1,993,753
at December 31, 1994, and 1995 and September 30, 1996, respectively. The
projects represented by these costs were at such dates undergoing exploration or
development activities or projects in which the Company intends to commence such
activities in the future. The Company will begin to amortize these costs when
proved reserves are established or impairment is determined. The Company
believes that the unevaluated properties at December 31, 1995 will be fully
evaluated in 24 to 36 months.
 
    The following table represents an analysis of remaining unevaluated oil and
gas property costs at December 31, 1995, and the periods in which they were
incurred:
 
<TABLE>
<CAPTION>
                                                                                   1994         1995
                                                                                ----------  ------------
<S>                                                                             <C>         <C>
Acquisition costs.............................................................  $  238,219  $    418,027
Exploration costs.............................................................     104,596       614,303
Development costs.............................................................           0             0
                                                                                ----------  ------------
    Total.....................................................................  $  342,815  $  1,032,330
                                                                                ----------  ------------
                                                                                ----------  ------------
</TABLE>
 
    The following table sets forth the costs incurred in the Company's oil and
gas property acquisition, exploration and development activities for the years
presented:
 
<TABLE>
<CAPTION>
                                                                                           NINE MONTHS
                                                                                              ENDED
                                                                                          SEPTEMBER 30,
                                                     1993         1994          1995          1996
                                                  ----------  ------------  ------------  -------------
<S>                                               <C>         <C>           <C>           <C>
Property acquisition costs--
  Proved........................................  $        0  $          0  $          0   $         0
  Unproved......................................      96,558       372,134       490,141       424,922
Exploration costs...............................     712,996     1,618,149     1,611,192     2,883,603
Development costs...............................           0             0             0       103,210
                                                  ----------  ------------  ------------  -------------
                                                  $  809,554  $  1,990,283  $  2,101,333   $ 3,411,735
                                                  ----------  ------------  ------------  -------------
                                                  ----------  ------------  ------------  -------------
</TABLE>
 
16. OIL AND GAS PRODUCING ACTIVITIES (UNAUDITED)
 
RESERVES
 
    The process of estimating proved developed and proved undeveloped oil and
gas reserves is very complex, requiring significant subjective decisions in the
evaluation of available geologic, engineering and economic data for each
reservoir. The data for a given reservoir may change over time as a result of,
among other things, additional development activity, production history and
viability of production under varying economic conditions. Consequently,
material revisions to existing reserve estimates may occur in the future.
Although every reasonable effort is made to ensure that reserve estimates are
based on the most accurate and complete information possible, the significance
of the subjective decisions required and variances in available data for various
reservoirs make these estimates generally less precise than other estimates
presented in connection with financial statement disclosures.
 
                                      F-27
<PAGE>
                             3DX TECHNOLOGIES INC.
 
                   NOTES TO FINANCIAL STATEMENTS (CONTINUED)
 
             (INFORMATION AS OF SEPTEMBER 30, 1996 AND FOR THE NINE
 
         MONTH PERIODS ENDED SEPTEMBER 30, 1995 AND 1996 IS UNAUDITED)
 
16. OIL AND GAS PRODUCING ACTIVITIES (UNAUDITED) (CONTINUED)
    The Company began its exploration program in 1993, by participating in an
exploration program as a royalty owner. The Company did not produce any
discovered oil and gas reserves in 1993.
 
    The Company added proved oil and gas reserves in 1994 as a result of
exploration efforts on one prospect.
 
    In 1995, the Company added proved reserves from one additional well in the
1994 prospect, and drilled one additional successful well in a new prospect. In
addition, there was a significant downward revision in oil and gas reserves
associated with the Bright Falcon project. The primary factors contributing to
the reserve revision include (1) the premature loss of a well due to mechanical
reasons which was unanticipated at the time of the initial estimate, and (2) the
removal of proved, undeveloped reserves attributable to a well location, which
the project partners elected not to drill.
 
    In the nine months ended September 30, 1996, the Company added proved
reserves from eight successful wells from drilling on various prospects. The
Company also made certain downward revisions to its previous estimates. Such
revisions result from additional production and performance information which
became available during 1996.
 
    The Company's oil and gas reserves, shown below, all of which are located in
the continental United States, consist of proved reserves which are estimated to
be recoverable in the future under economic and operating conditions.
 
    The following table sets forth the changes in the Company's total proved
reserves (all of which are developed) for the years ended December 31, 1993,
1994 and 1995.
<TABLE>
<CAPTION>
                                                                  YEAR ENDED               NINE MONTHS
                                                                 DECEMBER 31,                 ENDED
                                                       ---------------------------------  SEPTEMBER 30,
                                                         1993        1994        1995         1996
                                                       ---------  ----------  ----------  -------------
                                                                          OIL (BBLS)
                                                       ------------------------------------------------
<S>                                                    <C>        <C>         <C>         <C>
Proved reserves at the beginning of the period.......     --           4,000      39,886        41,193
Extensions, discoveries, and other additions.........      4,000      42,000      26,000         5,066
Revisions of previous estimates......................     --          --         (18,000)       (8,972)
Production...........................................     --          (6,114)     (6,693)       (6,499)
                                                       ---------  ----------  ----------  -------------
Proved reserves at the end of the period.............      4,000      39,886      41,193        30,788
                                                       ---------  ----------  ----------  -------------
                                                       ---------  ----------  ----------  -------------
 
<CAPTION>
 
                                                                          GAS (MCF)
                                                       ------------------------------------------------
<S>                                                    <C>        <C>         <C>         <C>
Proved reserves at the beginning of the period.......     --          20,000   1,236,915       442,795
Extensions, discoveries, and other additions.........     20,000   1,322,000     104,000     1,980,032
Revisions of previous estimates......................     --          --        (801,000)     (136,318)
Production...........................................     --        (105,085)    (97,120)     (117,772)
                                                       ---------  ----------  ----------  -------------
Proved reserves at the end of the period.............     20,000   1,236,915     442,795     2,168,737
                                                       ---------  ----------  ----------  -------------
                                                       ---------  ----------  ----------  -------------
</TABLE>
 
                                      F-28
<PAGE>
                             3DX TECHNOLOGIES INC.
 
                   NOTES TO FINANCIAL STATEMENTS (CONTINUED)
 
             (INFORMATION AS OF SEPTEMBER 30, 1996 AND FOR THE NINE
 
         MONTH PERIODS ENDED SEPTEMBER 30, 1995 AND 1996 IS UNAUDITED)
 
16. OIL AND GAS PRODUCING ACTIVITIES (UNAUDITED) (CONTINUED)
STANDARDIZED MEASURES OF DISCOUNTED FUTURE NET CASH FLOWS
 
    The Company's standardized measure of discounted future net cash flows, and
changes therein, related to proved oil and gas reserves are as follows (amounts
in thousands):
 
<TABLE>
<CAPTION>
                                                                         DECEMBER 31,
                                                            ---------------------------------------  SEPTEMBER 30,
                                                               1993         1994          1995           1996
                                                            ----------  ------------  -------------  -------------
<S>                                                         <C>         <C>           <C>            <C>
Future cash inflow........................................  $   84,000  $  2,997,000  $   1,405,000   $ 4,336,000
Future production, development and abandonment costs......        ( --)     (755,000)      (329,000)     (743,000)
                                                            ----------  ------------  -------------  -------------
Future cash flows before income taxes.....................      84,000     2,242,000      1,076,000     3,593,000
Future income taxes.......................................      --           --            --             --
                                                            ----------  ------------  -------------  -------------
Future net cash flows.....................................      84,000     2,242,000      1,076,000     3,593,000
10% Discount factor.......................................     (24,000)     (636,000)      (305,000)     (818,000)
                                                            ----------  ------------  -------------  -------------
Standardized measure of discounted future net cash flow...  $   60,000  $  1,606,000  $     771,000   $ 2,775,000
                                                            ----------  ------------  -------------  -------------
                                                            ----------  ------------  -------------  -------------
Changes in standardized measure of discounted future net
  cash flows:
  Sales of oil, gas and natural gas liquids, net of
    production costs......................................              $   (270,000) $    (196,000)  $  (357,000)
  Extensions, discoveries and other additions.............                 1,878,000        349,000     2,373,000
  Revisions of estimates of reserves proved in prior
    years:
    Quantities estimated..................................                   --          (1,280,000)     (338,000)
    Net changes in price and production cost..............                   --             (71,000)      153,000
  Accretion of discount...................................                     6,000        161,000        58,000
  Changes in future development costs.....................                  (112,000)       103,000        31,000
  Changes in production rates (timing) and other..........                    44,000         99,000        84,000
                                                                        ------------  -------------  -------------
  Net change..............................................              $  1,546,000  $    (835,000)  $ 2,004,000
                                                                        ------------  -------------  -------------
                                                                        ------------  -------------  -------------
</TABLE>
 
    Estimated future cash inflows are computed by applying year-end prices of
oil and gas to year-end quantities of proved reserves. Future price changes are
considered only to the extent provided by contractual arrangements. Estimated
future development and production costs are determined by estimating the
expenditures to be incurred in developing and producing the proved oil and gas
reserves at the end of the year, based on year-end costs and assuming
continuation of existing economic conditions. Estimated future income tax
expense is calculated by applying year-end statutory tax rates to estimated
future pretax net cash flows related to proved oil and gas reserves, less the
tax basis (including net operating loss carryforwards projected to be usable) of
the properties involved.
 
    These estimates were determined in accordance with SFAS No. 69. Because of
unpredictable variances in expenses and capital forecasts, crude oil and gas
prices and oil and gas reserve volume estimates, as well as the arbitrary
pricing and discounting assumptions used in these cash flow estimates,
 
                                      F-29
<PAGE>
                             3DX TECHNOLOGIES INC.
 
                   NOTES TO FINANCIAL STATEMENTS (CONTINUED)
 
             (INFORMATION AS OF SEPTEMBER 30, 1996 AND FOR THE NINE
 
         MONTH PERIODS ENDED SEPTEMBER 30, 1995 AND 1996 IS UNAUDITED)
 
16. OIL AND GAS PRODUCING ACTIVITIES (UNAUDITED) (CONTINUED)
management believes the usefulness of this data is limited. These estimates of
future net cash flows do not necessarily represent management's assessment of
estimated fair market value, future profitability or future cash flow to the
Company. Management's investment and operating decisions are based upon reserve
estimates that include proved as well as probable reserves and upon different
price and cost assumptions from those used herein.
 
    The future cash flows presented in the "Standardized Measures of Discounted
Future Net Cash Flows" are based on year-end oil and gas prices for oil and gas
reserves. The Company does not have oil and gas reserves which are committed
under oil and gas contracts.
 
                                      F-30
<PAGE>
                                                                      APPENDIX A
 
October 22, 1996
 
3DX Technologies Inc.
12012 Wickchester, Suite 250
Houston, TX 77079-1218
 
Gentlemen:
 
    The estimated reserve volumes and future income amounts presented in this
report are related to hydrocarbon prices. September 1996 hydrocarbon prices were
used in the preparation of this report as required by the Securities and
Exchange Commission (SEC) and Financial Accounting Standards Bulletin No. 69
(FASB 69) guidelines; however, actual future prices may vary significantly from
September 1996 prices. Therefore, volumes of reserves actually recovered and
amounts of income actually received may differ significantly from the estimated
quantities presented in this report.
 
    The Company's reserves are located in onshore and offshore Texas and in
Federal waters offshore Louisiana. Our estimates of the net proved reserves
attributable to the interests of 3DX Technologies Inc. (referred to herein as
the Company), as of September 30, 1996 are presented below:
 
<TABLE>
<CAPTION>
                                                                       PROVED NET RESERVES
                                                                     AS OF SEPTEMBER 30, 1996
                                                                  ------------------------------
                                                                    GAS, MMCF    LIQUID, BARRELS
                                                                  -------------  ---------------
<S>                                                               <C>            <C>
Developed and Undeveloped.......................................        2,146          27,305
Developed.......................................................        2,146          27,305
</TABLE>
 
    All hydrocarbon liquid reserves are expressed in standard 42 gallon barrels.
All gas volumes are sales gas expressed in MMCF at the pressure and temperature
bases of the area where the gas reserves are located.
 
    Proved reserves of crude oil, concentrate, natural gas, and natural gas
liquids are estimated quantities that geological and engineering data
demonstrate with reasonable certainty to be recoverable in the future from known
reservoirs under existing conditions. Reservoirs are considered proved if
economic producibility is supported by actual production or formation tests. In
certain instances, proved reserves are assigned on the basis of a combination of
core analysis and electrical and other type logs which indicate the reservoirs
are analogous to reservoirs in the same field which are producing or have
demonstrated the ability to produce on a formation test. The area of a reservoir
considered proved includes (1) that portion delineated by drilling and defined
by fluid contacts, if any, and (2) the adjoining portions not yet drilled that
can be reasonably judged as economically productive on the basis of available
geological and engineering data. In the absence of data on fluid contacts, the
lowest known structural occurrence of hydrocarbons controls the lower proved
limit of the reservoir. Proved reserves are estimates of hydrocarbons to be
recovered from a given date forward. They may be revised as hydrocarbons are
produced and additional data become available. Proved natural gas reserves are
comprised of non-associated, associated, and dissolved gas. An appropriate
reduction in gas reserves has been made for the expected removal of natural gas
liquids, for lease and plant fuel, and the exclusion of non-hydrocarbon gases if
they occur in significant quantities and are removed prior to sale. Reserves
that can be produced economically through the application of improved recovery
techniques are included in the proved classification when these qualifications
are met: (1) successful testing by a pilot project or the operation of an
installed program in the reservoir provides support for the engineering analysis
on which the project or program was based, and
 
                                      A-1
<PAGE>
(2) it is reasonably certain the project will proceed. Improved recovery
includes all methods for supplementing natural reservoir forces and energy, or
otherwise increasing ultimate recovery from a reservoir, including (1) pressure
maintenance, (2) cycling, and (3) secondary recovery in its original sense.
Improved recovery also includes the enhanced recovery methods of thermal,
chemical flooding, and the use of miscible and immiscible displacement fluids.
Estimates of proved reserves do not include crude oil, natural gas, or natural
gas liquids being held in underground storage. Depending on the status of
development, these proved reserves are further subdivided into:
 
        (i) "developed reserves" which are those proved reserves reasonably
    expected to be recovered through existing wells with existing equipment and
    operating methods, including (a) "developed producing reserves" which are
    those proved developed reserves reasonably expected to be produced from
    existing completion intervals now open for production in existing wells, and
    (b) "developed non-producing reserves" which are those proved developed
    reserves which exist behind the casing of existing wells which are
    reasonably expected to be produced through these wells in the predictable
    future where the cost of making such hydrocarbons available for production
    should be relatively small compared to the cost of a new well; and
 
        (ii) "undeveloped reserves" which are those proved reserves reasonably
    expected to be recovered from new wells on undrilled acreage, from existing
    wells where a relatively large expenditure is required, and from acreage for
    which an application of fluid injection or other improved recovery technique
    is contemplated where the technique has been proved effective by actual
    tests in the area in the same reservoir. Reserves from undrilled acreage are
    limited to those drilling units offsetting productive units that are
    reasonably certain of production when drilled. Proved reserves for other
    undrilled units are included only where it can be demonstrated with
    reasonable certaintity that there us continuity of production from the
    existing productive formation.
 
    The Company has interests in certain tracts which have substantial
additional hydrocarbon quantities which cannot be classified as proved and
consequently are not included herein. The Company has active exploratory and
development drilling programs which may result in the reclassification of
significant additional volumes to the proved category.
 
    In accordance with the requirements of FASB 69, our estimates of future cash
inflows, future costs and future net cash inflows before income tax as of
September 30, 1996 from this report are presented as follows:
 
<TABLE>
<CAPTION>
                                                                         AS OF SEPTEMBER 30,
                                                                                1996
                                                                       -----------------------
<S>                                                                    <C>
Future Cash Inflows..................................................       $   4,239,599
Future Costs
  Production.........................................................       $     549,092
  Development........................................................             183,571
                                                                              -----------
Future Net Cash Inflows Before Income Tax............................       $   3,506,936
Present Value at 10% Before Income Tax...............................       $   2,723,338
</TABLE>
 
    The future cash inflows are gross revenues before any deductions. The
production costs were based on current data and include production taxes, ad
valorem taxes and certain other items such as transportation costs in addition
to the operating costs directly applicable to the individual leases or wells.
The development costs were based on current data and include dismantlement and
abandonment costs net of salvage for properties where such costs are relatively
significant.
 
    The Company furnished us with gas prices in effect at September 30, 1996 and
with its forecasts of future gas prices which take into account SEC guidelines,
current market prices, and contract prices. In accordance with SEC guidelines,
the future gas prices used in this report make no alllowances for future gas
price increases which may occur as a result of inflation nor do they account for
seasonal variations in
 
                                      A-2
<PAGE>
gas prices which may occur future yearly average gas prices to be somewhat lower
than September 30, 1996 gas prices.
 
    The Company furnished us with liquid prices in effect at September 30, 1996
and these prices were held constant to depletion of the properties. In
accordance with SEC guidelines, changes in liquid prices subsequent to September
30, 1996 were not considered in this report.
 
    Operating costs for the leases and wells in this report were based on the
operating expense reports of the Company and include only these costs directly
applicable to the leases or wells. When applicable, the operating costs include
a portion of general and administrative costs allocated directly to the leases
and wells under terms of operating agreements. Development costs were furnished
to us by the Company and are based on authorizations for expenditure for the
proposed work or actual costs for similar projects. The current operating and
development costs were held constant throughout the life of the properties. The
estimated net cost of abandonment after salvage was included for properties
where abandonment costs net of salvage are significant. The estimates of the net
abandonment costs furnished by the Company were accepted without independent
verification. No deduction was made for indirect costs such as general
administration and overhead expenses, loan repayments, interest expenses and
exploration and development prepayments. No attempt was made to quantify or
otherwise account for any accumulated gas production imbalances that may exist.
 
    The estimates of reserves presented herein are based upon a detailed study
of the properties in which the Company owns an interest; however, we have not
made any field examination of the properties. No consideration was given in this
report to potential environmental liabilities which may exist nor were any costs
included for potential liability to restore and clean up damages, if any, caused
by past operating practices. The Company has informed us that they have
furnished us all of the accounts, records, geological and engineering data and
reports, and other data required for this investigation. The ownership
interests, prices, and other factual data furnished by the Company were accepted
without independent verification. The estimates presented in this report are
based on data available through September 1996.
 
    The reserves included in this report are estimates only and should not be
construed as being exact quantities. They may or may not be actually recovered,
and if recovered, the revenues therefrom and the actual costs related thereto
could be more or less than the estimated amounts. Moreover, estimates of
reserves may increase or decrease as a result of future operations. The future
production rates from wells now on production may be more or less than estimated
because of changes in market demand or allowables set by regulatory bodies.
 
    While it may reasonably be anticipated that the future prices received for
the sale of production and the operating costs and other costs relating to such
production may also increase or decrease from existing levels, such changes
were, in accordance with the rules adopted by the SEC, omitted from
consideration in making this evaluation.
 
    Neither we nor any of our employees have any interest in the subject
properties and neither the employment to make this study nor the compensation is
contingent on our estimates of reserves and future cash inflows for the subject
properties.
 
                                            Very truly yours,
                                           RYDER SCOTT COMPANY
                                           PETROLEUM ENGINEERS
                                            /s/ DON P. GRIFFIN
                                ------------------------------------------
                                           Don P. Griffin, P.E.
                                              VICE PRESIDENT
 
                                      A-3
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    NO DEALER, SALESPERSON OR ANY OTHER PERSON HAS BEEN AUTHORIZED TO GIVE ANY
INFORMATION OR TO MAKE ANY REPRESENTATIONS OTHER THAN THOSE CONTAINED IN THIS
PROSPECTUS IN CONNECTION WITH THE OFFER MADE BY THIS PROSPECTUS AND, IF GIVEN OR
MADE, SUCH INFORMATION OR REPRESENTATIONS MUST NOT BE RELIED UPON AS HAVING BEEN
AUTHORIZED BY THE COMPANY OR ANY OF THE UNDERWRITERS. NEITHER THE DELIVERY OF
THIS PROSPECTUS NOR ANY SALE MADE HEREUNDER SHALL, UNDER ANY CIRCUMSTANCES,
CREATE ANY IMPLICATION THAT THERE HAS BEEN NO CHANGE IN THE AFFAIRS OF THE
COMPANY SINCE THE DATES AS OF WHICH INFORMATION IS GIVEN IN THIS PROSPECTUS.
THIS PROSPECTUS DOES NOT CONSTITUTE AN OFFER OR SOLICITATION BY ANYONE IN ANY
JURISDICTION IN WHICH SUCH OFFER OR SOLICITATION IS NOT AUTHORIZED OR IN WHICH
THE PERSON MAKING SUCH OFFER OR SOLICITATION IS NOT QUALIFIED TO DO SO OR TO ANY
PERSON TO WHOM IT IS UNLAWFUL TO MAKE SUCH SOLICITATION.
 
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                               TABLE OF CONTENTS
 
<TABLE>
<CAPTION>
                                                                            PAGE
                                                                            ----
<S>                                                                         <C>
Prospectus Summary........................................................    3
Risk Factors..............................................................    9
The Company...............................................................   16
Use of Proceeds...........................................................   17
Dividend Policy...........................................................   17
Dilution..................................................................   18
Capitalization............................................................   19
Selected Financial Data...................................................   20
Management's Discussion and Analysis of Financial Condition and Results of
  Operations..............................................................   22
Business..................................................................   33
Management................................................................   49
Certain Transactions......................................................   55
Principal and Selling Stockholders........................................   57
Description of Capital Stock..............................................   58
Shares Eligible for Future Sale...........................................   62
Underwriting..............................................................   64
Legal Matters.............................................................   65
Experts...................................................................   65
Additional Information....................................................   65
Glossary of Certain Industry Terms........................................   67
Index to Financial Statements.............................................  F-1
Summary Report of Ryder Scott Company.....................................  A-1
</TABLE>
 
                            ------------------------
 
    UNTIL JANUARY 13, 1997 (25 DAYS AFTER THE DATE OF THIS PROSPECTUS), ALL
DEALERS EFFECTING TRANSACTIONS IN THE COMMON STOCK, WHETHER OR NOT PARTICIPATING
IN THIS DISTRIBUTION, MAY BE REQUIRED TO DELIVER A PROSPECTUS. THIS IS IN
ADDITION TO THE OBLIGATION OF DEALERS TO DELIVER A PROSPECTUS WHEN ACTING AS
UNDERWRITERS AND WITH RESPECT TO THEIR UNSOLD ALLOTMENTS OR SUBSCRIPTIONS.
 
                                2,500,000 SHARES
 
                             3DX TECHNOLOGIES INC.
 
                                     [LOGO]
 
                                  COMMON STOCK
 
                             ---------------------
 
                                   PROSPECTUS
 
                             ---------------------
 
                      HOWARD, WEIL, LABOUISSE, FRIEDRICHS
                                  INCORPORATED
 
                              PETRIE PARKMAN & CO.
 
                            DATED DECEMBER 19, 1996
 
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