<PAGE>

                                                                    EXHIBIT 99.1

                                 March 15, 2004

Edge Petroleum Corporation
1301 Travis Street, Suite 2000
Houston, Texas 77002

Gentlemen:

     At your request, we have prepared an estimate of the reserves, future
production, and income attributable to certain leasehold and royalty interests
of Edge Petroleum Corporation (Edge) as of December 31, 2003. The subject
properties are located in the states of Alabama, Louisiana, Mississippi, and
Texas. The income data were estimated using the Securities and Exchange
Commission (SEC) guidelines for future price and cost parameters.

     The estimated reserves and future income amounts presented in this report
are related to hydrocarbon prices. December 31, 2003 hydrocarbon prices were
used in the preparation of this report as required by SEC guidelines; however,
actual future prices may vary significantly from December 31, 2003 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 results of this study are summarized below.

                                 SEC PARAMETERS

                     ESTIMATED NET RESERVES AND INCOME DATA
                   CERTAIN LEASEHOLD AND ROYALTY INTERESTS OF
                           EDGE PETROLEUM CORPORATION
                            As of December 31, 2003

<Table>
<Caption>
                                                                     PROVED
                                              -----------------------------------------------------
                                                      DEVELOPED
                                              --------------------------                   TOTAL
                                              PRODUCING    NON-PRODUCING   UNDEVELOPED     PROVED
                                              ----------   -------------   -----------   ----------
<S>                                           <C>          <C>             <C>           <C>
NET REMAINING RESERVES
  Oil/Condensate -- Barrels.................     709,441       488,160        267,059     1,464,660
  Plant Products -- Barrels.................     628,805       278,203        479,404     1,386,412
  Gas -- MMCF...............................      22,449        14,489          9,886        46,824
INCOME DATA ($M)
  Future Gross Revenue......................  $157,550.2     $98,624.7      $72,447.8    $328,622.7
  Deductions................................    40,086.1      14,107.1       10,666.9      64,860.1
                                              ----------     ---------      ---------    ----------
  Future Net Income (FNI)...................  $117,464.1     $84,517.6      $61,780.9    $263,762.6
  Discounted FNI @ 10%......................  $ 87,717.8     $45,992.9      $45,215.2    $178,925.9
</Table>

     Liquid hydrocarbons are expressed in standard 42 gallon barrels. All gas
volumes are sales gas expressed in millions of cubic feet (MMCF) at the official
temperature and pressure bases of the areas in which the gas reserves are
located.

     The future gross revenue is after the deduction of production taxes. The
deductions are comprised of the normal direct costs of operating the wells, ad
valorem taxes, recompletion costs, and development costs. The future net income
is before the deduction of state and federal income taxes and general
administrative overhead, and has not been adjusted for outstanding loans that
may exist nor does it include any adjustment for cash on hand or undistributed
income. No attempt was made to quantify or otherwise account for any accumulated
gas production imbalances that may exist. Gas reserves account for approximately
83 percent and liquid hydrocarbon reserves account for the remaining 17 percent
of total future gross revenue from proved reserves.
<PAGE>

     The discounted future net income shown above was calculated using a
discount rate of 10 percent per annum compounded monthly. Future net income was
discounted at four other discount rates which were also compounded monthly.
These results are shown on each estimated projection of future production and
income presented in a later section of this report and in summary form below.

<Table>
<Caption>
                                                          DISCOUNTED FUTURE NET INCOME ($M)
                                                               AS OF DECEMBER 31, 2003
                                                          ---------------------------------
DISCOUNT RATE PERCENT                                               TOTAL PROVED
---------------------                                               ------------
<S>                                                       <C>
12.....................................................              $169,137.8
15.....................................................              $156,699.2
20.....................................................              $140,260.5
25.....................................................              $127,489.8
</Table>

     The results shown above are presented for your information and should not
be construed as our estimate of fair market value.

RESERVES INCLUDED IN THIS REPORT

     The proved reserves included herein conform to the definition as set forth
in the Securities and Exchange Commission's Regulation S-X Part 210.4-10 (a) as
clarified by subsequent Commission Staff Accounting Bulletins. The definitions
of proved reserves are included in the section entitled "Petroleum Reserves
Definitions" which is attached with this report.

     Because of the direct relationship between volumes of proved undeveloped
reserves and development plans, we include in the proved undeveloped category
only reserves assigned to undeveloped locations that we have been assured will
definitely be drilled, and reserves assigned to the undeveloped portions of
secondary or tertiary projects which we have been assured will definitely be
developed.

     The proved developed non-producing reserves included herein are comprised
of shut-in and behind pipe categories. The various reserve status categories are
defined in the section entitled "Petroleum Reserves Definitions" which is
attached with this report.

ESTIMATES OF RESERVES

     In general, the reserves included herein were estimated by performance
methods or the volumetric method; however, other methods were used in certain
cases where characteristics of the data indicated such other methods were more
appropriate in our opinion. The reserves estimated by the performance method
utilized extrapolations of various historical data in those cases where such
data were definitive. Reserves were estimated by the volumetric method in those
cases where there were inadequate historical performance data to establish a
definitive trend or where the use of production performance data as a basis for
the reserve estimates was considered to be inappropriate.

     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.

FUTURE PRODUCTION RATES

     Initial production rates are based on the current producing rates for those
wells now on production. Test data and other related information were used to
estimate the anticipated initial production rates for those wells or locations
which are not currently producing. If no production decline trend has been
established, future production rates were held constant, or adjusted for the
effects of curtailment where appropriate, until a decline in ability to produce
was anticipated. An estimated rate of decline was then applied to depletion of
the reserves. If a decline trend has been established, this trend was used as
the basis for estimating future

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<PAGE>

production rates. For reserves not yet on production, sales were estimated to
commence at an anticipated date furnished by Edge.

     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. Wells or locations which are not currently producing may
start producing earlier or later than anticipated in our estimates of their
future production rates.

HYDROCARBON PRICES

     Edge furnished us with hydrocarbon prices in effect at December 31, 2003
and with its forecasts of future prices which take into account SEC and
Financial Accounting Standards Board (FASB) rules, current market prices,
contract prices, and fixed and determinable price escalations where applicable.

     In accordance with FASB Statement No. 69, December 31, 2003 market prices
were determined using the daily oil price or daily gas sales price ("spot
price") adjusted for oilfield or gas gathering hub and wellhead price
differences (e.g. grade, transportation, gravity, sulfur and BS&W) as
appropriate. Also in accordance with SEC and FASB specifications, changes in
market prices subsequent to December 31, 2003 were not considered in this
report.

     For hydrocarbon products sold under contract, the contract price including
fixed and determinable escalations, exclusive of inflation adjustments, was used
until expiration of the contract. Upon contract expiration, the price was
adjusted to the current market price for the area and held at this adjusted
price to depletion of the reserves.

COSTS

     Operating costs for the leases and wells in this report are based on
information provided by Edge and include only those 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. No deduction was made for indirect costs
such as general administration and overhead expenses, loan repayments, interest
expenses, and exploration and development prepayments that are not charged
directly to the leases or wells.

     Development costs were furnished to us by Edge and are based on
authorizations for expenditure for the proposed work or actual costs for similar
projects. The estimated net cost of abandonment after salvage was included for
properties where abandonment costs net of salvage are significant. At the
request of Edge, their estimate of zero abandonment costs after salvage value
for onshore properties was used in this report. Ryder Scott has not performed a
detailed study of the abandonment costs nor the salvage value and makes no
warranty for Edge's estimate.

     Current costs were held constant throughout the life of the properties.

GENERAL

     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 rules adopted by the SEC, omitted from consideration in
making this evaluation.

     The estimates of reserves presented herein were based upon a detailed study
of the properties in which Edge 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. Edge 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

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<PAGE>

furnished by Edge were accepted without independent verification. The estimates
presented in this report are based on data available through December 2003.

     Edge has assured us of their intent and ability to proceed with the
development activities included in this report, and that they are not aware of
any legal, regulatory or political obstacles that would significantly alter
their plans.

     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 income for the subject
properties.

     This report was prepared for the exclusive use and sole benefit of Edge
Petroleum Corporation. The data, work papers, and maps used in this report are
available for examination by authorized parties in our offices. Please contact
us if we can be of further service.

                                          Very truly yours,

                                          RYDER SCOTT COMPANY, L.P.
                                          Michael F. Stell, P.E.
                                          Senior Vice President

MFS/sw

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<PAGE>

                         PETROLEUM RESERVES DEFINITIONS

                       SECURITIES AND EXCHANGE COMMISSION

INTRODUCTION

     Reserves are those quantities of petroleum which are anticipated to be
commercially recovered from known accumulations from a given date forward. All
reserve estimates involve some degree of uncertainty. The uncertainty depends
chiefly on the amount of reliable geologic and engineering data available at the
time of the estimate and the interpretation of these data. The relative degree
of uncertainty may be conveyed by placing reserves into one of two principal
classifications, either proved or unproved. Unproved reserves are less certain
to be recovered than proved reserves and may be further sub-classified as
probable and possible reserves to denote progressively increasing uncertainty in
their recoverability. It should be noted that Securities and Exchange Commission
Regulation S-K prohibits the disclosure of estimated quantities of probable or
possible reserves of oil and gas and any estimated value thereof in any
documents publicly filed with the Commission.

     Reserves estimates will generally be revised as additional geologic or
engineering data become available or as economic conditions change. Reserves do
not include quantities of petroleum being held in inventory, and may be reduced
for usage or processing losses if required for financial reporting.

     Reserves may be attributed to either natural energy or improved recovery
methods. Improved recovery methods include all methods for supplementing natural
energy or altering natural forces in the reservoir to increase ultimate
recovery. Examples of such methods are pressure maintenance, cycling,
waterflooding, thermal methods, chemical flooding, and the use of miscible and
immiscible displacement fluids. Other improved recovery methods may be developed
in the future as petroleum technology continues to evolve.

PROVED RESERVES (SEC DEFINITIONS)

     Securities and Exchange Commission Regulation S-X Rule 4-10 paragraph (a)
defines proved reserves as follows:

     Proved oil and gas reserves.  Proved oil and gas reserves are 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, i.e., prices and costs as of the date the estimate is made. Prices
include consideration of changes in existing prices provided only by contractual
arrangements, but not on escalations based upon future conditions.

     (i) Reservoirs are considered proved if economic producibility is supported
by either actual production or conclusive formation test. The area of a
reservoir considered proved includes:

          (A) that portion delineated by drilling and defined by gas-oil and/or
     oil-water contacts, if any; and

          (B) the immediately adjoining portions not yet drilled, but which can
     be reasonably judged as economically productive on the basis of available
     geological and engineering data. In the absence of information on fluid
     contacts, the lowest known structural occurrence of hydrocarbons controls
     the lower proved limit of the reservoir.

     (ii) Reserves which can be produced economically through application of
improved recovery techniques (such as fluid injection) are included in the
"proved" classification when 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.

     (iii) Estimates of proved reserves do not include the following:

          (A) oil that may become available from known reservoirs but is
     classified separately as "indicated additional reserves";
<PAGE>

          (B) crude oil, natural gas, and natural gas liquids, the recovery of
     which is subject to reasonable doubt because of uncertainty as to geology,
     reservoir characteristics, or economic factors;

          (C) crude oil, natural gas, and natural gas liquids, that may occur in
     undrilled prospects; and

          (D) crude oil, natural gas, and natural gas liquids, that may be
     recovered from oil shales, coal, gilsonite and other such sources.

     Proved developed oil and gas reserves.  Proved developed oil and gas
reserves are reserves that can be expected to be recovered through existing
wells with existing equipment and operating methods. Additional oil and gas
expected to be obtained through the application of fluid injection or other
improved recovery techniques for supplementing the natural forces and mechanisms
of primary recovery should be included as "proved developed reserves" only after
testing by a pilot project or after the operation of an installed program has
confirmed through production response that increased recovery will be achieved.

     Proved undeveloped reserves.  Proved undeveloped oil and gas reserves are
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. Reserves on undrilled acreage shall be limited to those drilling
units offsetting productive units that are reasonably certain of production when
drilled. Proved reserves for other undrilled units can be claimed only where it
can be demonstrated with certainty that there is continuity of production from
the existing productive formation. Under no circumstances should estimates for
proved undeveloped reserves be attributable to any acreage for which an
application of fluid injection or other improved recovery technique is
contemplated, unless such techniques have been proved effective by actual tests
in the area and in the same reservoir.

     Certain Staff Accounting Bulletins published subsequent to the promulgation
of Regulation S-X have dealt with matters relating to the application of
financial accounting and disclosure rules for oil and gas producing activities.
In particular, the following interpretations extracted from Staff Accounting
Bulletins set forth the Commission staff's view on specific questions pertaining
to proved oil and gas reserves.

     Economic producibility of estimated proved reserves can be supported to the
satisfaction of the Office of Engineering if geological and engineering data
demonstrate with reasonable certainty that those reserves can be recovered in
future years under existing economic and operating conditions. The relative
importance of the many pieces of geological and engineering data which should be
evaluated when classifying reserves cannot be identified in advance. In certain
instances, proved reserves may be assigned to reservoirs on the basis of a
combination of electrical and other type logs and core analyses which indicate
the reservoirs are analogous to similar reservoirs in the same field which are
producing or have demonstrated the ability to produce on a formation test.
(extracted from SAB-35)

     In determining whether "proved undeveloped reserves" encompass acreage on
which fluid injection (or other improved recovery technique) is contemplated, is
it appropriate to distinguish between (i) fluid injection used for pressure
maintenance during the early life of a field and (ii) fluid injection used to
effect secondary recovery when a field is in the late stages of depletion? ...
The Office of Engineering believes that the distinction identified in the above
question may be appropriate in a few limited circumstances, such as in the case
of certain fields in the North Sea. The staff will review estimates of proved
reserves attributable to fluid injection in the light of the strength of the
evidence presented by the registrant in support of a contention that enhanced
recovery will be achieved. (extracted from SAB-35)

     Companies should report reserves of natural gas liquids which are net to
their leasehold interest, i.e., that portion recovered in a processing plant and
allocated to the leasehold interest. It may be appropriate in the case of
natural gas liquids not clearly attributable to leasehold interests ownership to
follow instruction (b) of Item 2(b)(3) of Regulation S-K and report such
reserves separately and describe the nature of the ownership. (extracted from
SAB-35)

     The staff believes that since coalbed methane gas can be recovered from
coal in its natural and original location, it should be included in proved
reserves, provided that it complies in all other respects with the definition of
proved oil and gas reserves as specified in Rule 4-10(a)(2) including the
requirement that

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<PAGE>

methane production be economical at current prices, costs, (net of the tax
credit) and existing operating conditions. (extracted from SAB-85)

     Statements in Staff Accounting Bulletins are not rules or interpretations
of the Commission nor are they published as bearing the Commission's official
approval; they represent interpretations and practices followed by the Division
of Corporation Finance and the Office of the Chief Accountant in administering
the disclosure requirements of the Federal securities laws.

SUB-CATEGORIZATION OF DEVELOPED RESERVES (SPE/WPC DEFINITIONS)

     In accordance with guidelines adopted by the Society of Petroleum Engineers
(SPE) and the World Petroleum Congress (WPC), developed reserves may be
sub-categorized as producing or non-producing.

     Producing.  Reserves sub-categorized as producing are expected to be
recovered from completion intervals which are open and producing at the time of
the estimate. Improved recovery reserves are considered producing only after the
improved recovery project is in operation.

     Non-Producing.  Reserves sub-categorized as non-producing include shut-in
and behind pipe reserves. Shut-in reserves are expected to be recovered from (1)
completion intervals which are open at the time of the estimate but which have
not started producing, (2) wells which were shut-in awaiting pipeline
connections or as a result of a market interruption, or (3) wells not capable of
production for mechanical reasons. Behind pipe reserves are expected to be
recovered from zones in existing wells, which will require additional completion
work or future recompletion prior to the start of production.

                                        3