Exhibit
  99.3



YPF,
  S. A.



Vaca
  Muerta Oil Shale Project





Estimated

Future
  Reserves

Attributable
  to Certain

Interests



SEC
  Parameters



As
  of

December
  31, 2011

\s\
  Joseph E. BlankenshipJoseph E. Blankenship, P.E.
  TBPE License No. 62093
  Senior Vice President

[SEAL]

RYDER
  SCOTT COMPANY, L.P.TBPE Firm Registration No. F-1580

RYDER SCOTT
  COMPANY      PETROLEUM CONSULTANTS

---











February 6,
  2012

YPF, S. A.
  Macacha Guemes 515
  (C1035AAC)
  Ciudad Autónoma de Buenos Aires
  Argentina

Gentlemen:

At your request, Ryder
    Scott Company (Ryder Scott) has prepared an estimate of the proved reserves
    and future production attributable to certain interests of YPF, S. A. (YPF)
    in the Vaca Muerta Oil Shale Project, as of December 31, 2011. The subject
    properties are in various concessions located in the Neuquen Basin of Argentina.
    Although Ryder Scott also prepared an estimate of the proved future income,
    at YPFs request, it was not included in this report. The reserves and
    income data were estimated based on the definitions and disclosure guidelines
    of the United States Securities and Exchange Commission (SEC) contained in
    Title 17, Code of Federal Regulations, Modernization of Oil and Gas Reporting,
    Final Rule released January 14, 2009 in the Federal Register (SEC regulations).
    Our third party study, completed on January 18, 2012 and presented herein,
    was prepared for public disclosure by YPF in filings made with the SEC in
    accordance with the disclosure requirements set forth in the SEC regulations.


The properties evaluated
    by Ryder Scott account for a portion of YPFs total net proved reserves
    as of December 31, 2011. Based on information provided by YPF, the third party
    estimate conducted by Ryder Scott addresses 0.7 percent of the total proved
    developed net liquid hydrocarbon reserves, 0.3 percent of the total proved
    developed net gas reserves, 13.5 percent of the total proved undeveloped net
    liquid hydrocarbon reserves, and 8.2 percent of the total proved undeveloped
    net gas reserves of YPF.


The estimated reserves
    amounts presented in this report, as of December 31, 2011, 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 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, as required by the SEC regulations. Actual future prices may
    vary significantly from the prices required by SEC regulations; therefore,
    volumes of reserves actually recovered and the 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
        PARAMETERSEstimated Net Reserves
        Certain Interests ofYPF, S. A.
      As
        of December 31, 2011 | 
|------------------------------------------------------------------------------------------------------------------------- | 
|                                                                                                                          | 
|                                                                                                                          | 
|                                                                                                                          | 
|                                                                                                                          | 
|                                                                                                                          | 
|Net
      Remaining Reserves                                                                                              | 
|Oil/Condensate
       Barrels                                                                                            | 
|Gas
       MMCF                                                                                                          | 



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YPF, S. A.
  February 6, 2012
  Page 2

Liquid hydrocarbons are
    expressed in standard 42 gallon barrels. All gas volumes are reported on an
    as sold basis expressed in millions of cubic feet (MMCF) at the
    official temperature and pressure bases of the areas in which the gas reserves
    are located.


|Reserves
      Included in This Report
|--------------------------------------

The proved reserves included
    herein conform to 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.


The various proved reserve
    status categories are defined under the attachment entitled Petroleum
    Reserves Definitions in this report.


No attempt was made to
    quantify or otherwise account for any accumulated gas production imbalances
    that may exist. The provedgas volumes included herein do not attribute
    gas consumed in operations as 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. All reserve estimates involve an assessment
    of the uncertainty relating the likelihood that the actual remaining quantities
    recovered will be greater or less than the estimated quantities determined
    as of the date the estimate is made. 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. At YPFs request, this report addresses only
    the proved reserves attributable to the properties evaluated herein.


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. The proved reserves included herein
    were estimated using deterministic methods. If deterministic methods are used,
    the SEC has defined reasonable certainty for proved reserves as a high
    degree of confidence that the quantities will be recovered.


Provedreserve
    estimates will generally be revised only as additional geologic or engineering
    data become available or as economic conditions change. For proved reserves,
    the SEC states that as changes due to increased availability of geoscience
    (geological, geophysical, and geochemical), engineering, and economic data
    are made to the estimated ultimate recovery (EUR) with time, reasonably certain
    EUR is much more likely to increase or remain constant than to decrease.
    Moreover, estimates of proved reserves may be revised as a result of future
    operations, effects of regulation by governmental agencies or geopolitical
    or economic risks. Therefore, the proved reserves included in this report
    are estimates only and should not be construed as being exact quantities,
    and if recovered, the revenues therefrom, and the actual costs related thereto,
    could be more or less than the estimated amounts.


The proved reserves reported
    herein are limited to the period prior to expiration of current contracts
    providing the legal rights to produce, or a revenue interest in such production,
    unless evidence indicates that contract renewal is reasonably certain. Furthermore,
    properties in the different concessions may be subjected to significantly
    varying contractual fiscal terms that affect the net




RYDER SCOTT
  COMPANY      PETROLEUM CONSULTANTS



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YPF, S. A.
  February 6, 2012
  Page 3

revenue to YPF for 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 YPF 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 nor our acceptance of YPFs
  representations regarding such contractual information should be construed as
  a legal opinion on this matter.

This report includes certain
    volumes of proved reserves attributable to royalties owed to the host government
    that are treated as taxes to be paid in cash. A royalty equal to 12 percent
    of revenue from sales of hydrocarbons is owed on all of the concessions included
    in this report. Beginning January 1, 2018, on only the Loma La Lata concession,
    additional royalty of 5 percent of net profits is owed-the net profit is defined
    to include profit or losses from all producing horizons, not just the Vaca
    Muerta zone, which this report addresses.


Ryder Scott did not evaluate
    the country and geopolitical risks in the countries where YPF operates or
    has interests. YPFs operations may be subject to various levels of governmental
    controls and regulations. These controls and regulations may include, but
    may not be limited to, matters relating to land tenure and leasing, the legal
    rights to produce hydrocarbons including the granting, extension or termination
    of production license contracts, the fiscal terms of various production license
    contracts, drilling and 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 proved reserves actually recovered and amounts of proved income actually
    received to differ significantly from the estimated quantities.


The estimates of proved
    reserves presented herein were based upon a detailed study of the properties
    in which YPF 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
    liabilities to restore and clean up damages, if any, caused by past operating
    practices.


|Estimates
      of Reserves
|---------------------------

The estimation of reserves
    involves two distinct determinations. The first determination results in the
    estimation of the quantities of recoverable oil and gas and the second determination
    results in the estimation of the uncertainty associated with those estimated
    quantities in accordance with the definitions set forth by the Securities
    and Exchange Commissions Regulations Part 210.4-10(a). The process of
    estimating the quantities of recoverable oil and gas reserves relies on the
    use of certain generally accepted analytical procedures. These analytical
    procedures fall into three broad categories or methods: (1) performance-based
    methods; (2) volumetric-based methods; and (3) analogy. These methods may
    be used singularly or in combination by the reserve evaluator in the process
    of estimating the quantities of reserves. Reserve evaluators must select the
    method or combination of methods which in their professional judgment is most
    appropriate given the nature and amount of reliable geoscience and engineering
    data available at the time of the estimate, the established or anticipated
    performance characteristics of the reservoir being evaluated and the stage
    of development or producing maturity of the property.


In many cases, the analysis
    of the available geoscience and engineering data and the subsequent interpretation
    of this data may indicate a range of possible outcomes in an estimate,




RYDER SCOTT
  COMPANY      PETROLEUM CONSULTANTS



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YPF, S. A.
  February 6, 2012
  Page 4

irrespective of the method
  selected by the evaluator. When a range in the quantity of reserves is identified,
  the evaluator must determine the uncertainty associated with the incremental
  quantities of the reserves. If the reserve quantities are estimated using the
  deterministic incremental approach, the uncertainty for each discrete incremental
  quantity of the reserves is addressed by the reserve category assigned by the
  evaluator. Therefore, it is the categorization of reserve quantities as proved,
  probable and/or possible that addresses the inherent uncertainty in the estimated
  quantities reported. For proved reserves, uncertainty is defined by the SEC
  as reasonable certainty wherein the quantities actually recovered are
  much more likely than not to be achieved. The SEC states that probable
  reserves are those additional reserves that are less certain to be recovered
  than proved reserves but which, together with proved reserves, are as likely
  as not to be recovered. The SEC states that possible reserves are
  those additional reserves that are less certain to be recovered than probable
  reserves and the total quantities ultimately recovered from a project have a
  low probability of exceeding proved plus probable plus possible reserves.
  All quantities of reserves within the same reserve category must meet the SEC
  definitions as noted above.

Estimates of reserves
    quantities and their associated reserve categories may be revised in the future
    as additional geoscience or engineering data become available. Furthermore,
    estimates of reserves quantities and their associated reserve categories may
    also be revised due to other factors such as changes in economic conditions,
    results of future operations, effects of regulation by governmental agencies
    or geopolitical or economic risks as previously noted herein.


The proved reserves for
    the properties included herein were estimated by performance methods, the
    volumetric method, analogy, or a combination of methods. Approximately
    100 percent of the proved producing reserves attributable to producing wells
    and/or reservoirs were estimated by performance methods and analogy to offsetting
    producers. These performance methods include, but may not be limited
    to, decline curve analysis which utilized extrapolations of historical production
    and pressure data available through November, 2011 in those cases where such
    data were considered to be definitive. The data utilized in this analysis
    were furnished to Ryder Scott by YPF or obtained from public data sources
    and were considered sufficient for the purpose thereof.


Approximately 100 percent
    of the proved undeveloped reserves included herein were estimated by analogy
    and the volumetric method.The volumetric analysis utilized pertinent
    well and seismic data furnished to Ryder Scott by YPF or which we have obtained
    from public data sources that were available through November, 2011. The data
    utilized from theanalogues as well as well and seismic data incorporated
    into our volumetric analysis were considered sufficient for the purpose thereof.


The reserves are based
    on primary recovery from the Vaca Muerta oil shale. All wells and locations
    are the vertical type; none are horizontal. The development plan includes
    multistage fracture treatments.


To estimate economically
    recoverable proved 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 that 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 anticipated to be economically producible from a given date forward based
    on existing economic conditions including the prices and costs at which economic
    producibility from a reservoir is to be determined. 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 increase
    or decrease from those under existing economic conditions, such changes were,
    in accordance with rules adopted by the SEC, omitted from consideration in
    making this evaluation.




RYDER SCOTT
  COMPANY      PETROLEUM CONSULTANTS



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YPF, S. A.
  February 6, 2012
  Page 5

YPF has informed us that
    they have furnished us all of the material accounts, records, geological and
    engineering data, and reports and other data required for this investigation.
    In preparing our forecast of future proved production and income, we have
    relied upon data furnished by YPF with respect to property interests owned,
    production and well tests from examined wells, normal direct costs of operating
    the wells or leases, other costs such as transportation and/or processing
    fees, ad valorem and production taxes, provincial sales tax, recompletion
    and development costs, abandonment costs after salvage, product prices based
    on the SEC regulations, adjustments or differentials to product prices, geological
    structural and isochore maps, well logs, core analyses, and pressure measurements.
    Ryder Scott reviewed such factual data for its reasonableness; however, we
    have not conducted an independent verification of the data furnished by YPF.
    We consider the factual data used in this report appropriate and sufficient
    for the purpose of preparing the estimates of reserves herein.


In summary, we consider
    the assumptions, data, methods and analytical procedures used in this report
    appropriate for the purpose hereof, and we have used all such methods and
    procedures that we consider necessary and appropriate to prepare the estimates
    of reserves herein. The proved reserves included herein were determined in
    conformance with the United States Securities and Exchange Commission (SEC)
    Modernization of Oil and Gas Reporting; Final Rule, including all references
    to Regulation S-X and Regulation S-K, referred to herein collectively as the
    SEC Regulations. In our opinion, the proved reserves presented
    in this report comply with the definitions, guidelines and disclosure requirements
    as required by the SEC regulations.


|Future
      Production Rates
|-----------------------------

For wells currently on
    production, our forecasts of future production rates are based on historical
    performance data. If no production decline trend had 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 had been established, this trend was used as the basis
    for estimating future production rates.


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. For reserves
    not yet on production, sales were estimated to commence at an anticipated
    date furnished by YPF. Wells or locations that are not currently producing
    may start producing earlier or later than anticipated in our estimates due
    to unforeseen factors causing a change in the timing to initiate production.
    Such factors may include delays due to weather, the availability of rigs,
    the sequence of drilling, completing and/or recompleting wells and/or constraints
    set by regulatory bodies.


The future production
    rates from wells currently on production or wells or locations that are not
    currently producing may be more or less than estimated because of changes
    including, but not limited to, reservoir performance, operating conditions
    related to surface facilities, compression and artificial lift, pipeline capacity
    and/or operating conditions, producing market demand and/or allowables or
    other constraints set by regulatory bodies.


|Hydrocarbon
      Prices
|------------------------

The hydrocarbon prices
    used herein are based on SEC price parameters using 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




RYDER SCOTT
  COMPANY      PETROLEUM CONSULTANTS



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YPF, S. A.
  February 6, 2012
  Page 6

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.

YPF furnished us with
    the above mentioned average prices in effect on December 31, 2011. These initial
    SEC hydrocarbon prices were determined using the 12-month average first-day-of-the-month
    benchmark prices appropriate to the geographic area where the hydrocarbons
    are sold. These benchmark prices are prior to the adjustments for differentials
    as described herein. The table below summarizes the benchmark prices
    and price reference used for the geographic area included in the
    report. In certain geographic areas, the price reference and benchmark prices
    may be defined by contractual arrangements.


The product prices that
    were actually used to determine the future gross revenue for each property
    reflect adjustments to the benchmark prices for gravity, quality, local conditions,
    distance from market, and the export tax in Argentina, referred to herein
    as differentials. The differentials used in the preparation of
    this report were furnished to us by YPF. The differentials furnished to us
    were accepted as factual data and reviewed by us for their reasonableness;
    however, we have not conducted an independent verification of the data used
    by YPF to determine these differentials.


The export tax in Argentina,
    which currently reduces the SEC price on these properties from $95.99 to $61.35
    per barrel, by law, is scheduled to end on December 31, 2016. Therefore, after
    December 31, 2016, YPF increased the SEC price from $61.35 to $95.99 per barrel.
    YPF informs us that the SEC has reviewed, commented on and allowed this interpretation
    in YPFs previous filings.


In addition, the table
    below summarizes the net volume weighted benchmark prices adjusted for differentials
    and referred to herein as the average realized prices. The average
    realized prices shown in the table below were determined from the total future
    gross revenue before production taxes and the total net reserves for the geographic
    area and presented in accordance with SEC disclosure requirements for each
    of the geographic areas included in the report.


|                      |  |                |  |                         |  |                                          |  |                                         | 
|--------------------- |  | -------------- |  | ----------------------- |  | ---------------------------------------- |  | --------------------------------------- | 
|Geographic
      Area |  | Product        |  | Price
        Reference |  | Average
        Benchmark
        Prices |  | Average
        Realized
        Prices | 
|                      |  |                |  |                         |  |                                          |  |                                         | 
|                      |  | Oil/Condensate |  | WTI
        Cushing     |  | $96.19/Bbl                               |  | $77.91/Bbl                              | 
|Argentina             |  |                |  |                         |  |                                          |  |                                         | 
|                      |  | Gas            |  | Henry
        Hub       |  | $4.12/MMBTU                              |  | $2.62/MCF                               | 
|                      |  |                |  |                         |  |                                          |  |                                         | 

The effects of derivative
    instruments designated as price hedges of oil and gas quantities are not reflected
    in our individual property evaluations.


|Costs
|-----

Operating costs for the
    leases and wells in this report are based on YPFs projection of future
    operating costs for this project due to lack of historical cost data at this
    early stage of development, 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 leases and wells. The operating
    costs furnished by YPF were reviewed by us for their reasonableness; however,
    we have not conducted an independent verification of the data used by YPF
    to project these operating costs. No deduction was made for loan repayments,
    interest expenses, or exploration and development prepayments that were not
    charged directly to the leases or wells.




RYDER SCOTT
  COMPANY      PETROLEUM CONSULTANTS



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YPF, S. A.
  February 6, 2012
  Page 7

Development costs were
    furnished to us by YPF and are based on authorizations for expenditure for
    the proposed work or actual costs for similar projects. The development costs
    furnished to us were accepted as factual data and reviewed by us for their
    reasonableness; however, we have not conducted an independent verification
    of these costs. The estimated net cost of abandonment after salvage was included
    for properties. The estimates of the net abandonment costs furnished by YPF
    were accepted without independent verification.


The proved undeveloped
    reserves in this report have been incorporated herein in accordance with YPFs
    plans to develop these reserves as of December 31, 2011. The implementation
    of YPFs development plans as presented to us and incorporated herein
    is subject to the approval process adopted by YPFs management. As the
    result of our inquiries during the course of preparing this report, YPF has
    informed us that the development activities included herein have been subjected
    to and received the internal approvals required by YPFs management at
    the appropriate local, regional and/or corporate level. In addition to the
    internal approvals as noted, certain development activities may still be subject
    to specific partner AFE processes, Joint Operating Agreement (JOA) requirements
    or other administrative approvals external to YPF. Additionally, YPF has informed
    us that they are not aware of any legal, regulatory, political or economic
    obstacles that would significantly alter their plans. All of YPFs proved
    undeveloped reserves are scheduled to be developed within five years from
    the initial disclosure in an SEC report.


Current costs used by
    YPF were held constant throughout the life of the properties.


|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 privately-owned
    or 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.


We are independent petroleum
    engineers with respect to YPF. 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.




RYDER SCOTT
  COMPANY      PETROLEUM CONSULTANTS



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YPF, S. A.
  February 6, 2012
  Page 8

The results of this study,
    presented herein, are based on technical analysis conducted by teams of geoscientists
    and engineers from Ryder Scott. The professional qualifications of the undersigned,
    the technical person primarily responsible for overseeing, reviewing and approving
    the evaluation of the reserves information discussed in this report, are included
    as an attachment to this letter.


|Terms
      of Usage
|--------------------

The results of our third
    party study, presented in report form herein, were prepared in accordance
    with the disclosure requirements set forth in the SEC regulations and intended
    for public disclosure as an exhibit in filings made with the SEC by YPF.


YPF makes periodic filings
    on Form 20-F with the SEC under the 1934 Exchange Act. We have consented to
    the incorporation by reference in the registration statement as well as to
    the references to our third party report for YPF, which appears in the December
    31, 2011 annual report on Form 20-F of YPF.


We have provided YPF with
    a digital version of the original signed copy of this report letter. In the
    event there are any differences between the digital version included in filings
    made by YPF and the original signed report letter, the original signed report
    letter shall control and supersede the digital version.


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\
        Joseph E. Blankenship                                                                | 
| |                                                                                                  | 
| |                                                                                                  | 
| | Joseph
        E. Blankenship, P.E.
        TBPE License No. 62093
        Senior Vice President | 

[SEAL]

JEB/pl



RYDER SCOTT
  COMPANY      PETROLEUM CONSULTANTS



---









Professional
  Qualifications of Primary Technical Person

The conclusions presented
  in this report are the result of technical analysis conducted by teams of geoscientists
  and engineers from Ryder Scott Company, L.P. Mr. Joseph E. Blankenship was the
  primary technical person responsible for overseeing the estimation and evaluation
  process with respect to the preparation of this report.

Mr. Blankenship, an employee
  of Ryder Scott Company L.P. (Ryder Scott) since 1982, is a Senior Vice President
  and also serves as chief technical advisor for unconventional reserves evaluation.
  Mr. Blankenship is responsible for coordinating and supervising staff and consulting
  engineers of the company in ongoing reservoir evaluation studies worldwide.
  Before joining Ryder Scott, Mr. Blankenship served in a number of engineering
  positions with Exxon Company USA. For more information regarding Mr. Blankenships
  geographic and job specific experience, please refer to the Ryder Scott Company
  website at www.ryderscott.com/Experience/Employees.

Mr. Blankenship earned a
  Bachelor of Science degree in Mechanical Engineering from the University of
  Alabama in 1977. He is a member of the Honorary Engineering Society Pi Tau Sigma
  and is a licensed Professional Engineer in the State of Texas. He is also a
  member of the Society of Petroleum Engineers (SPE) and the Society of Petroleum
  Evaluation Engineers (SPEE). He has served as Chairman of the SPE Newsletter
  Committee and has been invited by the SPEE to lecture on the subject of Coal
  Seam evaluation.

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. Blankenship
  fulfills. Mr. Blankenships continuing education in 2011 included classes
  on professional resource planning, Microsoft Access utilization in the area
  of reserves evaluation, Fekete Reservoir Engineering Software optimization and
  utilization, and the utilization of correct SEC Reserves and PRMS Resource evaluation
  criteria.

In 2010, Mr. Blankenship
  presented 1hour of formalized training to the professional staff at
  Ryder Scott. Mr. Blankenship attended Ryder Scotts 2010 Reserves Conference,
  which included a presentation by Dr. John Lee, on the new SEC regulations relating
  to 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; and Mr. Blankenship also attended a class on Deep Water Gulf of Mexico
  reserves evaluation.

In 2009, Mr. Blankenship
  attended 41 hours of formalized training covering such topics as the SPE/WPC/AAPG/SPEE
  Petroleum Resources Management System (PRMS), reservoir engineering, geoscience
  and petroleum economics evaluation methods, procedures and software and ethics
  for consultants. Mr. Blankenship was class instructor in Ryder Scotts
  2009 and 2010 in-house courses on unconventional reserves evaluation.

Based on his educational
  background, professional training and more than 34 years of practical experience
  in the estimation and evaluation of petroleum reserves, Mr. Blankenship 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.



RYDER SCOTT
  COMPANY      PETROLEUM CONSULTANTS



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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 (direct passages excerpted in part or wholly
    from the aforementioned SEC document are denoted in italics herein).


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. All reserve estimates involve an assessment
    of the uncertainty relating the likelihood that the actual remaining quantities
    recovered will be greater or less than the estimated quantities determined
    as of the date the estimate is made. 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 SEC. 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 SEC 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 only 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.


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.




RYDER SCOTT
  COMPANY      PETROLEUM CONSULTANTS



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PETROLEUM RESERVES DEFINITIONS
  Page 2

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
| |  | ------------------------------------------------------------------------------------

| |  | (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.
| | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

RYDER SCOTT
  COMPANY      PETROLEUM CONSULTANTS



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PETROLEUM RESERVES DEFINITIONS
  Page 3

|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.
| | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

|PROBABLE
      RESERVES (SEC DEFINITIONS)
|-----------------------------------------

Securities and Exchange
    Commission Regulation S-X §210.4-10(a)(18) defines probable oil and gas
    reserves as follows:


Probable reserves.Probable reserves are those additional reserves that are less certain
  to be recovered than proved reserves but which, together with proved reserves,
  are as likely as not to be recovered.

| | (i)
      When deterministic methods are used, it is as likely as not that actual
      remaining quantities recovered will exceed the sum of estimated proved plus
      probable reserves. When probabilistic methods are used, there should be
      at least a 50% probability that the actual quantities recovered will equal
      or exceed the proved plus probable reserves estimates.
| | -----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

| | (ii)
      Probable reserves may be assigned to areas of a reservoir adjacent to proved
      reserves where data control or interpretations of available data are less
      certain, even if the interpreted reservoir continuity of structure or productivity
      does not meet the reasonable certainty criterion. Probable reserves may
      be assigned to areas that are structurally higher than the proved area if
      these areas are in communication with the proved reservoir.
| | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

| | (iii)
      Probable reserves estimates also include potential incremental quantities
      associated with a greater percentage recovery of the hydrocarbons in place
      than assumed for proved reserves.
| | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

| | (iv)
      See also guidelines in paragraphs (a)(17)(iv) and (a)(17)(vi) of this section.
| | -----------------------------------------------------------------------------------------

RYDER SCOTT
  COMPANY      PETROLEUM CONSULTANTS



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PETROLEUM RESERVES DEFINITIONS
  Page 4

|POSSIBLE
      RESERVES (SEC DEFINITIONS)
|-----------------------------------------

Securities and Exchange
    Commission Regulation S-X §210.4-10(a)(17) defines possible oil and gas
    reserves as follows:


Possible reserves.Possible reserves are those additional reserves that are less certain
  to be recovered than probable reserves.

| | (i)
      When deterministic methods are used, the total quantities ultimately recovered
      from a project have a low probability of exceeding proved plus probable
      plus possible reserves. When probabilistic methods are used, there should
      be at least a 10% probability that the total quantities ultimately recovered
      will equal or exceed the proved plus probable plus possible reserves estimates.
| | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

| | (ii)
      Possible reserves may be assigned to areas of a reservoir adjacent to probable
      reserves where data control and interpretations of available data are progressively
      less certain. Frequently, this will be in areas where geoscience and engineering
      data are unable to define clearly the area and vertical limits of commercial
      production from the reservoir by a defined project.
| | -----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

| | (iii)
      Possible reserves also include incremental quantities associated with a
      greater percentage recovery of the hydrocarbons in place than the recovery
      quantities assumed for probable reserves.
| | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

| | (iv)
      The proved plus probable and proved plus probable plus possible reserves
      estimates must be based on reasonable alternative technical and commercial
      interpretations within the reservoir or subject project that are clearly
      documented, including comparisons to results in successful similar projects.
| | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

| | (v)
      Possible reserves may be assigned where geoscience and engineering data
      identify directly adjacent portions of a reservoir within the same accumulation
      that may be separated from proved areas by faults with displacement less
      than formation thickness or other geological discontinuities and that have
      not been penetrated by a wellbore, and the registrant believes that such
      adjacent portions are in communication with the known (proved) reservoir.
      Possible reserves may be assigned to areas that are structurally higher
      or lower than the proved area if these areas are in communication with the
      proved reservoir.
| | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

| | (vi)
      Pursuant to paragraph (a)(22)(iii) of this section, where direct observation
      has defined a highest known oil (HKO) elevation and the potential exists
      for an associated gas cap, proved oil reserves should be assigned in the
      structurally higher portions of the reservoir above the HKO only if the
      higher contact can be established with reasonable certainty through reliable
      technology. Portions of the reservoir that do not meet this reasonable certainty
      criterion may be assigned as probable and possible oil or gas based on reservoir
      fluid properties and pressure gradient interpretations.
| | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------



RYDER SCOTT
  COMPANY      PETROLEUM CONSULTANTS



---









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.
| | -------------------------------------------------------------------------------------------------------------------------



RYDER SCOTT
  COMPANY      PETROLEUM CONSULTANTS



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RESERVES STATUS DEFINITIONS
  AND GUIDELINES
  Page 2

| | Developed
      Non-ProducingDeveloped Non-Producing Reserves include shut-in and behind-pipe reserves.
| | -------------------------------------------------------------------------------------------------------

| | Shut-InShut-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 for market conditions or pipeline connections; or
| |  | --- | --------------------------------------------------------------------------------

| |  | (3) | wells
      not capable of production for mechanical reasons.
| |  | --- | -------------------------------------------------------------

| | Behind-PipeBehind-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.
| |  | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------



RYDER SCOTT
  COMPANY      PETROLEUM CONSULTANTS



---