Exhibit 99.1
  ECOPETROL
 
 Third
Party Independent Audit of
   Estimated
Future Reserves
   Attributable
to Certain Interests
  in
Colombia
 
 SEC
Parameters
 
 As
of
  December
31, 2009
     
 /s/ Herman G. AcuñaHerman
      G. Acuña, P.E.TBPE
      License No. 92254Managing
      Senior Vice President—International[SEAL]
 
 RYDER
SCOTT COMPANY, L.P.
 TBPE Firm
Registration No. F-1580
 
 RYDER
SCOTT COMPANY      PETROLEUM
CONSULTANTS
  
  
 
 TBPE
      REGISTERED ENGINEERING FIRM F-1580
                  
                  FAX
      (713) 651-08491100
      LOUISIANA
                  
                  SUITE
      3800
                  
                  HOUSTON,
      TEXAS 77002-5218
                  
                  TELEPHONE
      (713) 651-9191
 
 April 15,
2010
 
 ECOPETROL
 Calle 37
No. 8-43 Piso 12
 Bogota,
D.C., Colombia
 
 Ladies
and Gentlemen:
 
 At your
request, Ryder Scott Company has prepared an estimate of the proved reserves,
future production and income attributable to certain properties of Ecopetrol, as
of December 31, 2009.  The subject properties are located in the
country of Colombia.
 
 The
reserves and income data were estimated based on the definitions and disclosure
guidelines contained in the United States Securities and Exchange Commission
Title 17, Code of Federal Regulations, Modernization of Oil and Gas Reporting,
Final Rule released January 14, 2009 in the Federal Register (SEC
regulations).  The conclusions of our third party study, completed on
January 25, 2010, are discussed herein.
 
 The
conclusions discussed in this report, as of December 31, 2009, are related to
hydrocarbon prices.  The hydrocarbon prices used in the preparation of
this report are based on the average prices during the 12-month period prior to
the ending date of the period covered in this report, determined as unweighted
arithmetic averages of the prices in effect on the first-day-of-the-month for
each month within such period, unless prices were defined by contractual
arrangements as required by the SEC regulations.  Actual future prices
may vary significantly from the prices required by SEC regulations; therefore,
the conclusions of our third party study may differ significantly from the
discussion below.
 
 Ecopetrol
has opted to represent that Ryder Scott Company conducted these 3rd party
independent estimations; accordingly, Ryder Scott Company has prepared this
report for inclusion as an exhibit to the relevant registration statement or
other Commission filings by Ecopetrol.
 
 Scope
of 3rd Party
Independent Audit
 
 At the
request of Ecopetrol, Ryder Scott Company conducted an independent estimation of
the reserves, future production and income associated with certain assets in
which Ecopetrol owns an interest.  Ryder Scott Company was provided
with both interpreted and uninterpreted data.  Based on this
information, Ryder Scott Company conducted the necessary studies to estimate and
audit the proved reserves to conform with our understanding of the definition as
set forth in the Securities and Exchange Commission’s Regulations Part 210.4-10
(a).  An abridged version of the SEC reserves definitions from
210.4-10(a) entitled “Petroleum Reserves Definitions” is included as an
attachment to this report.
 
 During
our investigations, no attempt was made to quantify or otherwise account for any
accumulated gas production imbalances that may exist.  Ecopetrol does
not include fuel gas in their estimation of net reserves, therefore, our
conclusion herein are exclusive of these volumes.
  1200,  530
      8TH  AVENUE, S.W. CALGARY, ALBERTA T2P 3S8
                        
                        TEL
      (403) 262-2799
                        
                        FAX
      (403) 262-2790621  17TH
      STREET, SUITE 1550 DENVER, COLORADO 80293-1501
                        
                        TEL
      (303) 623-9147
                        
                        FAX
      (303) 623-4258
  
 Ecopetrol
 April 15,
2010
 Page
2
 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.
 
 Proved
oil and gas reserves are those quantities of oil and gas, which, by analysis of
geoscience and engineering data, can be estimated with reasonable certainty to
be economically producible from a given date forward.  However, most
of the parameters that define the reserves of a reservoir cannot be measured
directly, and must be estimated indirectly through geologic and reservoir
engineering analysis and interpretations.  As a result, the estimates
of oil and gas reserves have an  intrinsic uncertainty, Moreover,
estimates of reserves may increase or decrease as a result of future operations,
effects of regulation by governmental agencies or geopolitical
risks.  As a result, the estimates of oil and gas reserves have an
intrinsic uncertainty.  The reserves included in this report are
therefore 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.
 
 The
conclusion reported herein are limited to the period prior to expiration of
current contracts providing the legal right to produce or a revenue interest in
such production unless evidence indicates that contract renewal is reasonably
certain.  Furthermore, while we have only examined Ecopetrol’s
properties located in Colombia, properties in different countries may be
subjected to significantly varying contractual fiscal terms that may affect the
net revenue to Ecopetrol from the production of these volumes.  The
prices and economic return received for these net volumes can vary significantly
based on the terms of these contracts.  Therefore, when applicable,
Ryder Scott reviewed the fiscal terms of such contracts and discussed with
Ecopetrol the net economic benefit attributed to such operations for the
determination of the net hydrocarbon volumes and income
thereof.  Ryder Scott has not conducted an exhaustive audit or
verification of such contractual information.  Neither our review of
such contractual information or our acceptance of Ecopetrol’s representations
regarding such contractual information should be construed as a legal or
accounting opinion on this matter.
 
 Ryder
Scott did not evaluate country and geopolitical risks in the countries where
Ecopetrol operates or has interests.  Ecopetrol’s operations may be
subject to various levels of governmental controls and
regulations.  These controls and regulations may include matters
relating to land tenure, drilling, production practices, environmental
protection, marketing and pricing policies, royalties, various taxes and levies
including income tax, and foreign trade and investment and are subject to change
from time to time.  Such changes in governmental regulations and
policies may cause volumes of reserves actually recovered and amounts of income
actually received to differ significantly from the estimated
quantities.
 
 The
conclusions presented herein were based upon a detailed study of the properties
in which Ecopetrol 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 that may exist nor were any costs
included for potential liability to restore and clean up damages, if any, caused
by past operating practices.
 
 The
properties reviewed by Ryder Scott Company are located in the country of
Colombia and do not represent the entire asset portfolio from
Ecopetrol.  Ecopetrol has indicated that the proved net reserves
attributable to the properties that we reviewed account for 28 percent of their
total proved net remaining hydrocarbon reserves.
    
  Ecopetrol
 April 15,
2010
 Page
3
  Data,
Methods and Procedures
 
 In
performing our estimates, we have relied upon data furnished by Ecopetrol with
respect to property interests owned, production and well tests from examined
wells, historical costs of operation and development, product prices, geological
structural and isochors maps, well logs, core analyses, and pressure
measurements, etc.  In general, the reserve estimates for the
properties that we reviewed are based on data available through December 31,
2009.
 
 These
data were accepted as authentic and sufficient for determining the reserves
unless, during the course of our examination, a matter of question came to our
attention in which case the data were not accepted until all questions were
satisfactorily resolved.
 
 As
prescribed by the Society of Petroleum Engineers in Paragraph 2.2(f) of the
Standards Pertaining to the Estimating and Auditing of Oil and Gas Reserves
Information a reserves audit is defined as “the process of reviewing certain of
the pertinent facts interpreted and assumptions made that have resulted in an
estimate of reserves prepared by others and the rendering of an opinion about
(1) the appropriateness of the methodologies employed, (2) the adequacy and
quality of the data relied upon, (3) the depth and thoroughness of the reserves
estimation process, (4) the classification of reserves appropriate to the
relevant definitions used, and (5) the reasonableness of the estimated reserve
quantities.”
 
 In
general, the reserves included herein were estimated by performance method,
volumetric or material balance methods; however, other methods were used in
certain cases where characteristics of the data, in our opinion, indicated such
other methods were more appropriate.
 
 Our
forecasts of future production rates are based on historical performance from
wells now on production.  Test data and other related information were
used to estimate the anticipated initial production rates for those wells or
locations that 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
production rates.  For reserves not yet on production, sales were
estimated to commence at an anticipated date furnished by
Ecopetrol  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 that are not
currently producing may start producing earlier or later than anticipated in our
estimates.
 
 To
estimate economically recoverable oil and gas reserves and related future net
cash flows, we consider many factors and assumptions including, but not limited
to, the use of reservoir parameters derived from geological, geophysical and
engineering data which cannot be measured directly, economic criteria based on
current costs and SEC pricing requirements, and forecasts of future production
rates.  Under the SEC regulations 210.4-10(a)(22)(v) and (26), proved
reserves must be demonstrated to be economically producible based on existing
economic conditions including the prices and costs at which economic
producibility from a reservoir is to be determined as of the effective date of
the report.
 
 As
previously stated, the hydrocarbon prices used herein are based on the average
prices during the 12-month period prior to the ending date of the period covered
in this report, determined as the unweighted arithmetic averages of the prices
in effect on the first-day-of-the-month for each month within such period,
unless prices were defined by contractual arrangements.  For
hydrocarbon products sold under contract, the contract prices including fixed
and determinable escalations, exclusive of inflation adjustments, were used
until expiration of the contract.  Upon contract expiration, the
prices were adjusted to the 12-month unweighted arithmetic average as previously
described.
    
 Ecopetrol
 April 15,
2010
 Page
4
 Ecopetrol
has informed us that the operating costs for the assets in this report are based
on the operating expense reports of Ecopetrol and include only those costs
directly applicable to the leases or wells. The operating costs include a
portion of general and administrative costs allocated directly to the assets.
When applicable for operated properties, the operating costs include an
appropriate level of corporate general administrative and overhead
costs.  No deduction was made for loan repayments, interest expenses,
or exploration and development prepayments that were not charged directly to the
assets.  Development costs were furnished to us by Ecopetrol 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 was
significant.  Ryder Scott reviewed such factual data for its
reasonableness; however, we have not conducted an independent verification of
the data supplied by Ecopetrol.
 
 Summary
of Ryder Scott Company Conclusions
 
 In our
opinion, Ecopetrol’s estimates of future reserves for the reviewed properties
were prepared in accordance with generally accepted petroleum engineering and
evaluation principles for the estimation of future reserves as set forth in the
Standards Pertaining to the Estimating and Auditing of Oil and Gas Reserves
Information, and we found no bias in the utilization and analysis of data in
estimates for these properties.
 
 The
overall proved reserves for the reviewed properties as estimated by Ecopetrol
are, in the aggregate, reasonable within the established audit tolerance
guidelines of equal or less than 10 percent as set forth in the Standards
Pertaining to the Estimating and Auditing of Oil and Gas Reserves Information
promulgated by the Society of Petroleum Engineers.
 
 Standards
of Independence and Professional Qualification
 
 Ryder
Scott is an independent petroleum engineering consulting firm that has been
providing petroleum consulting services throughout the world for over seventy
years.  Ryder Scott is employee owned and maintains offices in
Houston, Texas; Denver, Colorado; and Calgary, Alberta, Canada.  We
have over eighty engineers and geoscientists on our permanent
staff.  By virtue of the size of our firm and the large number of
clients for which we provide services, no single client or job represents a
material portion of our annual revenue.  We do not serve as officers
or directors of any publicly traded oil and gas company and are separate and
independent from the operating and investment decision-making process of our
clients.  This allows us to bring the highest level of independence
and objectivity to each engagement for our services.
 
 Ryder
Scott actively participates in industry related professional societies and
organizes an annual public forum focused on the subject of reserves evaluations
and SEC regulations.  Many of our staff have authored or co-authored
technical papers on the subject of reserves related topics.  We
encourage our staff to maintain and enhance their professional skills by
actively participating in ongoing continuing education.
 
 Prior to
becoming an officer of the Company, Ryder Scott requires that staff engineers
and geoscientists have received professional accreditation in the form of a
registered or certified professional engineer’s license or a registered or
certified professional geoscientist’s license, or the equivalent thereof, from
an appropriate governmental authority or a recognized self-regulating
professional organization.
    
 Ecopetrol
 April 15,
2010
 Page
5
 We are
independent petroleum engineers with respect to Ecopetrol  Neither we
nor any of our employees have any interest in the subject properties and neither
the employment to do this work nor the compensation is contingent on our
estimates of reserves for the properties which were reviewed.
 
 The
conclusions presented in this report are the result of technical analysis
conducted by teams of geoscientists and engineers.  The professional
qualifications of the undersigned, the technical person primarily responsible
for overseeing this project, is included as an attachment to this
letter.
 
 Terms
of Usage
 
 This
report was prepared for the exclusive use and sole benefit of Ecopetrol Company
and may not be put to other use without our prior written consent for such
use.  The data and work papers used in the preparation of 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.TBPE
      Firm Registration No. F-1580/s/ Herman G. AcuñaHerman
      G. Acuña, P.E.TBPE
      License No. 92254Managing
      Senior Vice President–International[SEAL]
 
 HGA/sm
    
  Professional
Qualifications
 Herman
G. Acuña
 
 The
conclusions presented in this report for Ecopetrol for properties located in
Colombia are the result of technical analysis conducted by teams of
geoscientists and engineers from Ryder Scott Company, L.P.  Herman G.
Acuña was the primary technical person responsible for overseeing the
independent estimation of the reserves, future production and income to render
the audit conclusions of the report.
 
 Mr.
Acuña, an employee of Ryder Scott Company L.P. (Ryder Scott) since 1997, is a
Managing Senior International Vice President and serves as an Engineering Group
Coordinator responsible for coordinating and supervising staff and consulting
engineers of the company in ongoing reservoir evaluation studies
worldwide.  Before joining Ryder Scott, Mr. Acuña served in a number
of engineering positions with Exxon.  For more information regarding
Mr. Acuña’s geographic and job specific experience, please refer to the Ryder
Scott Company website at www.ryderscott.com.
 
 Mr. Acuña
earned a Bachelor (Cum Laude) and a Masters (Magna Cum Laude) of Science degree
in Petroleum Engineering from The University of Tulsa in 1987 and 1989
respectively.  He is a registered Professional Engineer in the State
of Texas, a member of the Association of International Petroleum Negotiators
(AIPN) and the Society of Petroleum Engineers (SPE).
 
 In
addition to gaining experience and competency through prior work experience, the
Texas Board of Professional Engineers requires a minimum of fifteen hours of
continuing education annually, including at least one hour in the area of
professional ethics, which Mr. Acuña fulfills.  As part of his 2009
continuing education hours, Mr. Acuña attended over 34 hours of formalized
training and conferences including 10 hours dedicated to the subject of the
definitions and disclosure guidelines contained in the United States Securities
and Exchange Commission Title 17, Code of Federal Regulations, Modernization of
Oil and Gas Reporting, Final Rule released January 14, 2009 in the Federal
Register.  In 2009, Mr. Acuña taught various company reserves
evaluation schools in Argentina, Bolivia, China, Spain, U.S.A and
Venezuela.  Mr. Acuña has participated in various capacities in
reserves conferences such as being a panelist a the 2008 Trinidad and Tobago’s
Petroleum Conference, delivering the reserves evaluation seminar during IAPG
convention in Mendoza, Argentina in 2006 and chairing the first Reserves
Evaluation Conference in the Middle East in Dubai, U.A.E in 2006.
 
 Based on
his educational background, professional training and 20 years of practical
experience in petroleum engineering and the estimation and evaluation of
petroleum reserves, Mr. Acuña has attained the professional qualifications as a
Reserves Estimator and Reserves Auditor set forth in Article III of the
“Standards Pertaining to the Estimating and Auditing of Oil and Gas Reserves
Information” promulgated by the Society of Petroleum Engineers as of February
19, 2007.
    
  PETROLEUM
RESERVES DEFINITIONS
 
 As
Adapted From:
 RULE
4-10(a) of REGULATION S-X PART 210
 UNITED
STATES SECURITIES AND EXCHANGE COMMISSION (SEC)
 
 PREAMBLE
 
 On
January 14, 2009, the United States Securities and Exchange Commission (SEC)
published the “Modernization of Oil and Gas Reporting; Final Rule” in the
Federal Register of National Archives and Records Administration
(NARA).  The “Modernization of Oil and Gas Reporting; Final Rule”
includes revisions and additions to the definition section in Rule 4-10 of
Regulation S-X, revisions and additions to the oil and gas reporting
requirements in Regulation S-K, and amends and codifies Industry Guide 2 in
Regulation S-K.  The “Modernization of Oil and Gas Reporting; Final
Rule”, including all references to Regulation S-X and Regulation S-K, shall be
referred to herein collectively as the “SEC Regulations”.  The SEC
Regulations take effect for all filings made with the United States Securities
and Exchange Commission as of December 31, 2009, or after January 1,
2010.  Reference should be made to the full text under Title 17, Code
of Federal Regulations, Regulation S-X Part 210, Rule 4-10(a) for the complete
definitions, as the following definitions, descriptions and explanations rely
wholly or in part on excerpts from the original document (direct passages
excerpted from the aforementioned SEC document are denoted in italics
herein).
 
 Reserves
are those estimated remaining quantities of petroleum which are anticipated to
be economically producible, as of a given date, from known accumulations under
defined conditions.  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.  Under the SEC Regulations as of December 31,
2009, or after January 1, 2010, a company may optionally disclose estimated
quantities of probable or possible oil and gas reserves in documents publicly
filed with the Commission.  The SEC Regulations continue to prohibit
disclosure of estimates of oil and gas resources other than reserves and any
estimated values of such resources in any document publicly filed with the
Commission unless such information is required to be disclosed in the document
by foreign or state law as noted in §229.1202 Instruction to Item
1202.
 
 Reserves
estimates will generally be revised as additional geologic or engineering data
become available or as economic conditions change.
 
 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, natural gas 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.
    
 PETROLEUM
RESERVES DEFINITIONS
 Page
2
 Reserves
may be attributed to either conventional or unconventional petroleum
accumulations.  Petroleum accumulations are considered as either
conventional or unconventional based on the nature of their in-place
characteristics, extraction method applied, or degree of processing prior to
sale.  Examples of unconventional petroleum accumulations include
coalbed or coalseam methane (CBM/CSM), basin-centered gas, shale gas, gas
hydrates, natural bitumen and oil shale deposits.  These
unconventional accumulations may require specialized extraction technology
and/or significant processing prior to sale.
 Reserves
do not include quantities of petroleum being held in inventory.
 
 Because
of the differences in uncertainty, caution should be exercised when aggregating
quantities of petroleum from different reserves categories.
 
 RESERVES (SEC
DEFINITIONS)
 
 Securities
and Exchange Commission Regulation S-X §210.4-10(a)(26) defines reserves as
follows:
 
 Reserves.Reserves
are estimated remaining quantities of oil and gas and related substances
anticipated to be economically producible, as of a given date, by application of
development projects to known accumulations.  In addition, there must
exist, or there must be a reasonable expectation that there will exist, the
legal right to produce or a revenue interest in the production, installed means
of delivering oil and gas or related substances to market, and all permits and
financing required to implement the project.
 
 Note to paragraph
(a)(26): Reserves should not be assigned to adjacent reservoirs isolated
by major, potentially sealing, faults until those reservoirs are penetrated and
evaluated as economically producible.  Reserves should not be assigned
to areas that are clearly separated from a known accumulation by a
non-productive reservoir (i.e., absence of
reservoir, structurally low reservoir, or negative test
results).  Such areas may contain prospective resources (i.e., potentially
recoverable resources from undiscovered accumulations).
 
 PROVED RESERVES (SEC
DEFINITIONS)
 
 Securities
and Exchange Commission Regulation S-X §210.4-10(a)(22) defines proved oil and
gas reserves as follows:
 
 Proved oil and gas
reserves.Proved oil and gas reserves are those quantities of
oil and gas, which, by analysis of geoscience and engineering data, can be
estimated with reasonable certainty to be economically producible—from a given
date forward, from known reservoirs, and under existing economic conditions,
operating methods, and government regulations—prior to the time at which
contracts providing the right to operate expire, unless evidence indicates that
renewal is reasonably certain, regardless of whether deterministic or
probabilistic methods are used for the estimation. The project to extract the
hydrocarbons must have commenced or the operator must be reasonably certain that
it will commence the project within a reasonable time.
 
 (i)
The area of the reservoir considered as proved includes:
 
 (A)
The area identified by drilling and limited by fluid contacts, if any,
and
    
 PETROLEUM
RESERVES DEFINITIONS
 Page
3
 (B)
Adjacent undrilled portions of the reservoir that can, with reasonable
certainty, be judged to be continuous with it and to contain economically
producible oil or gas on the basis of available geoscience and engineering
data.
 
 (ii)
In the absence of data on fluid contacts, proved quantities in a reservoir are
limited by the lowest known hydrocarbons (LKH) as seen in a well penetration
unless geoscience, engineering, or performance data and reliable technology
establishes a lower contact with reasonable certainty.
 
 PROVED RESERVES (SEC
DEFINITIONS) CONTINUED
 
 (iii)
Where direct observation from well penetrations has defined a highest known oil
(HKO) elevation and the potential exists for an associated gas cap, proved oil
reserves may be assigned in the structurally higher portions of the reservoir
only if geoscience, engineering, or performance data and reliable technology
establish the higher contact with reasonable certainty.
 (iv)
Reserves which can be produced economically through application of improved
recovery techniques (including, but not limited to, fluid injection) are
included in the proved classification when:
 (A)
Successful testing by a pilot project in an area of the reservoir with
properties no more favorable than in the reservoir as a whole, the operation of
an installed program in the reservoir or an analogous reservoir, or other
evidence using reliable technology establishes the reasonable certainty of the
engineering analysis on which the project or program was based; and
 
 (B)
The project has been approved for development by all necessary parties and
entities, including governmental entities.
 
 (v)
Existing economic conditions include prices and costs at which economic
producibility from a reservoir is to be determined. The price shall be the
average price during the 12-month period prior to the ending date of the period
covered by the report, determined as an unweighted arithmetic average of the
first-day-of-the-month price for each month within such period, unless prices
are defined by contractual arrangements, excluding escalations based upon future
conditions.
 
 [Remainder
of this page is left blank intentionally.]
    
  RESERVES
STATUS DEFINITIONS AND GUIDELINES
 
 As
Adapted From:
 RULE
4-10(a) of REGULATION S-X PART 210
 UNITED
STATES SECURITIES AND EXCHANGE COMMISSION (SEC)
 
 and
  PETROLEUM
RESOURCES MANAGEMENT SYSTEM (SPE-PRMS)
 Sponsored
and Approved by:
 SOCIETY
OF PETROLEUM ENGINEERS (SPE),
 WORLD
PETROLEUM COUNCIL (WPC)
 AMERICAN
ASSOCIATION OF PETROLEUM GEOLOGISTS (AAPG)
 SOCIETY
OF PETROLEUM EVALUATION ENGINEERS (SPEE)
 
 Reserves
status categories define the development and producing status of wells and
reservoirs.  Reference should be made to Title 17, Code of Federal
Regulations, Regulation S-X Part 210, Rule 4-10(a) and the SPE-PRMS as the
following reserves status definitions are based on excerpts from the original
documents (direct passages excerpted from the aforementioned SEC and SPE-PRMS
documents are denoted in italics herein).
 
 DEVELOPED RESERVES (SEC
DEFINITIONS)
 
 Securities
and Exchange Commission Regulation S-X §210.4-10(a)(6) defines developed oil and
gas reserves as follows:
 
 Developed
oil and gas reserves are reserves of any category that can be expected to be
recovered:
 
 (i)
Through existing wells with existing equipment and operating methods or in which
the cost of the required equipment is relatively minor compared to the cost of a
new well; and
 
 (ii)
Through installed extraction equipment and infrastructure operational at the
time of the reserves estimate if the extraction is by means not involving a
well.
 
 Developed Producing
(SPE-PRMS Definitions)
 
 While not
a requirement for disclosure under the SEC regulations, developed oil and gas
reserves may be further sub-classified according to the guidance contained in
the SPE-PRMS as Producing or Non-Producing.
 
 Developed
Producing Reserves
 Developed
Producing Reserves are expected to be recovered from completion intervals that
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.
    
 RESERVES
STATUS DEFINITIONS AND GUIDELINES
 Page
2
 Developed
Non-Producing
 Developed
Non-Producing Reserves include shut-in and behind-pipe reserves.
 
 Shut-In
 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
      yet started producing;
 (2)
              wells
      which were shut-in for market conditions or pipeline connections;
      or
 (3)
              wells
      not capable of production for mechanical
  reasons.
 
 Behind-Pipe
 Behind-pipe
Reserves are expected to be recovered from zones in existing wells which will
require additional completion work or future re-completion prior to start of
production.
 
 In
all cases, production can be initiated or restored with relatively low
expenditure compared to the cost of drilling a new well.
 
 UNDEVELOPED RESERVES (SEC
DEFINITIONS)
 
 Securities
and Exchange Commission Regulation S-X §210.4-10(a)(31) defines undeveloped oil
and gas reserves as follows:
 
 Undeveloped
oil and gas reserves are reserves of any category 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.
 
 (i) Reserves
on undrilled acreage shall be limited to those directly offsetting development
spacing areas that are reasonably certain of production when drilled, unless
evidence using reliable technology exists that establishes reasonable certainty
of economic producibility at greater distances.
 
 (ii)
Undrilled locations can be classified as having undeveloped reserves only if a
development plan has been adopted indicating that they are scheduled to be
drilled within five years, unless the specific circumstances, justify a longer
time.
 
 (iii)
Under no circumstances shall estimates for 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 projects in the same reservoir or an analogous reservoir, as
defined in paragraph (a)(2) of this section, or by other evidence using reliable
technology establishing reasonable certainty.