Exhibit
      99





[Letterhead
      of Netherland, Sewell & Associates, Inc.]





January
      19, 2006








Kerr-McGee
      Oil & Gas Corporation


16666
      Northchase Drive


Houston,
      Texas 77060





Ladies
      and Gentlemen:





In
      accordance with your request, we have completed a review of the procedures
      and
      methods used by Kerr-McGee Oil & Gas Corporation (Kerr-McGee) in preparing
      its estimates of proved reserves and future revenue, as of December 31, 2005,
      in
      certain oil and gas properties located in the United States and China. These
      reserve and future revenue estimates were prepared by Kerr-McGee’s internal
      technical staff. In addition, modifications to Kerr-McGee’s reserve manual were
      reviewed to ensure that it confirms to Securities and Exchange Commission (SEC)
      regulations and guidelines.





The
      opinions expressed herein are based on our involvement as a participant in
      reviews of certain oil and gas properties and our exposure to Kerr-McGee’s
      reserve estimating process. In total, 27 field reserve review meetings were
      conducted in Kerr-McGee’s offices in Houston and Dallas, Texas; Denver,
      Colorado; and Beijing, China. The review meetings took place from April through
      November of 2005, with final follow-up responses completed in December 2005.
      The
      initial meetings generally ranged in duration from three to eight hours for
      each
      field with follow-up questions, comments, and replies conducted throughout
      the
      last half of 2005. It is our understanding that the properties reviewed
      represented a total of 738.3 million barrels-of-oil equivalent or approximately
      76.3 percent of the total proved reserves of Kerr-McGee as of December 31,
      2005.





The
      goals of the reviews were to verify that Kerr-McGee’s reserve estimates were
      prepared in accordance with the guidelines and definitions of the SEC using
      generally accepted petroleum engineering and evaluation principles and to
      determine, for the properties reviewed, the reasonableness of Kerr-McGee’s
      methods, procedures, and estimates. The reviews focused on reserve determination
      methodologies, procedures, and the data used in preparing the
      estimates.





For
      our
      reviews, we met with Kerr-McGee’s personnel and reviewed the geologic and
      engineering procedures and methodologies used as well as the resulting reserve
      estimates prepared by Kerr-McGee. Presented to us were future development plans
      and the basis for reserves and oil and gas projections. The information and
      data
      presented may have included, but were not necessarily limited to, geological
      and
      geophysical interpretations; structure, isopach, and amplitude maps; 3-D seismic
      data on paper; datum pressure and temperature; formation test results; fluid
      gradient analysis; well log curves; petrophysical zone summaries and calculation
      methodology; fluid property analysis; results of reservoir simulation and
      material balance modeling; well and field performance data; reserve analogies;
      statistical reserve analysis; future development plans; operating expenses;
      and
      reserves and flowstreams.





Although
      we have not completed independent reserve estimates, it is our judgment that
      the
      reviews were sufficient to determine that the general methods and procedures
      used by Kerr-McGee in the reserve estimation process are reasonable. In our
      opinion, the estimates for those properties reviewed have been prepared in
      accordance with SEC guidelines and definitions using generally accepted
      petroleum engineering and evaluation principles.





It
      should be understood that this was a review of procedures, methods, and certain
      internal estimates only and does not constitute a complete review, study, or
      audit of Kerr-McGee’s estimated proved reserves and future revenue. We did not
      consider Kerr-McGee’s probable or possible reserve estimates in the review
      process but may have seen these estimates on certain properties as related
      to
      overall reserve distributions. We did not independently verify the accuracy
      and
      completeness of information and data furnished by Kerr-McGee with respect to
      ownership interest, oil and gas production, well test data, historical costs
      of
      operation and development, product prices, or any agreements relating to current
      and future operations of the properties and sales of production. However, if
      in
      the course of our examination something came to our attention which brought
      into
      question the validity or sufficiency of any such information or data, we did
      not
      rely on such information or data until we had satisfactorily resolved our
      questions relating thereto or had independently verified such information or
      data. Our review did not include a review of Kerr-McGee’s overall reserves
      management processes and practices. In the course of our review, we did not
      perform any field inspection of the properties, nor did we examine the
      mechanical operations or condition of the wells and their related facilities.
      We
      have not investigated possible environmental liability related to the
      properties.








As
      in
      all aspects of oil and gas evaluation, there are uncertainties inherent in
      the
      interpretation of engineering and geologic data. Our assessment represents
      only
      informed professional judgment related to the procedures and methods used by
      Kerr-McGee in preparing its estimates of proved reserves and future
      revenue.





Netherland,
      Sewell & Associates, Inc. is a firm of professionals dedicated to providing
      superior consulting service to the international petroleum industry. Our company
      has provided due diligence, technical support, and economic evaluations for
      private and government companies and financial institutions throughout the
      world. We are independent petroleum engineers, geologists, geophysicist, and
      petrophysicists with respect to Kerr-McGee Oil & Gas Corporation as provided
      in the Standards Pertaining to the Estimating and Auditing of Oil and Gas
      Reserve Information promulgated by the Society of Petroleum Engineers. We do
      not
      own an interest in these properties and are not employed on a contingent
      basis.





Very
                truly yours,NETHERLAND,
                SEWELL & ASSOCIATES, INC.By:
                /s/ C. H. (Scott) Rees IIIC.
                H. (Scott) Rees III, P.E.President
                and Chief Operating OfficerBy:
                /s/ David B. Cox
            
            By:
                /s/ Patrick L. HiggsDavid
                B. Cox, P.E.
            
            Patrick
                L. Higgs, P.G.Senior
                Vice President
            
            Vice
                PresidentDate
                Signed: January 19, 2006
            
            Date
                Signed: January 19, 2006DBC:SAT