621 SEVENTEENTH STREET
SUITE 1550
DENVER, COLORADO 80293
FAX (303) 623-4258 
TELEPHONE (303) 623-9147




March 5, 2010











Petroleum Development Corporation


120 Genesis Boulevard


Bridgeport, West Virginia  26330





Gentlemen:





At your request, we have prepared an estimate of the reserves, future production, and income attributable to certain leasehold and royalty interests of Petroleum Development Corporation’s (“PDC”) PDC RR06LP Partnership as of December 31, 2009.  The subject properties are located in the state of Colorado.  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 estimated reserves and future net income amounts presented 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, 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 PARAMETERS


Estimated Net Reserves and Income Data


Certain Leasehold and Royalty Interests of


Petroleum Development Corporation Partnership: PDC RR06LP As of December 31, 2009
 
 ProvedDeveloped 
Producing


Undeveloped


Total 
ProvedNet Remaining ReservesOil/Condensate – Barrels


510,410



577,931



1,088,340Gas – MMCF


13,182



2,894



16,076Income Data M$Future Gross Revenue

$
64,014


$
43,332


$
107,346Deductions


34,308



17,319



51,627Future Net Income (FNI)

$
29,706


$
26,013


$
55,719Discounted FNI @ 10%

$
20,699


$
11,334


$
32,033
 
 Petroleum Development Corporation
 March 5, 2010
 Page 2


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





The estimates of the reserves, future production, and income attributable to properties in this report were prepared using the economic software package Aries for Windows, a copyrighted program of Landmark Graphics.  The program was used solely at the request of PDC.  Ryder Scott has found this program to be generally acceptable, but notes that certain summaries and calculations may vary due to rounding and may not exactly match the sum of the properties being summarized.  Furthermore, one line economic summaries may vary slightly from the more detailed cash flow projections of the same properties, also due to rounding.  The rounding differences are not material.





The future gross revenue is after the deduction of production taxes.  The deductions comprise the normal direct costs of operating the wells, ad valorem taxes, recompletion costs, development costs and certain abandonment costs. The future net income is before the deduction of state and federal income taxes and general administrative overhead, and has not been adjusted for outstanding loans that may exist nor does it include any adjustment for cash on hand or undistributed income.  No attempt was made to quantify or otherwise account for any accumulated gas production imbalances that may exist.  Liquid hydrocarbon reserves account for approximately 54 percent and gas reserves account for the remaining 46 percent of total future gross revenue from proved reserves.





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





Discounted Future Net Income $M 
As of December 31, 2009Discount Rate 
Percent

Total 
Proved5

$41,16415

$25,97420

$21,75725

$18,702





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





Reserves Included in This Report





The proved reserves included herein conform to the definition as set forth in the Securities and Exchange Commission’s 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 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 gas volumes included herein do not attribute gas consumed in operations as reserves.


Petroleum Development Corporation
 March 5, 2010
 Page 3




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.  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.





PDC’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 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 estimates of reserves presented herein were based upon a detailed study of the properties in which PDC RR06LP Partnership 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.





Estimates of Reserves





In general, the reserves included herein were estimated by performance methods or the analogy method.  The reserves estimated by the performance method utilized extrapolations of various historical data in those cases where such data were definitive in our opinion.  Reserves were estimated by analogy in those cases where there were inadequate historical performance data to establish a definitive trend.





The reserves included in this report are estimates only and should not be construed as being exact quantities.  They may or may not be actually recovered, and if recovered, the revenues therefrom and the actual costs related thereto could be more or less than the estimated amounts.  Moreover, estimates of reserves may increase or decrease as a result of future operations.





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 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.  PDC has informed us that they have furnished us all of the accounts, records, geological and engineering data, and reports and other data required for this investigation.  In preparing our forecast of future production and income, we have relied upon data furnished by PDC 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,  recompletion costs, development costs and abandonment costs after salvage and product prices based on the SEC regulations. Ryder Scott reviewed such factual data for its reasonableness; however, we have not conducted an independent verification of the data supplied by PDC.  It is our opinion that the assumptions and data utilized in this report are reasonable and appropriate.




Petroleum Development Corporation
 March 5, 2010
 Page 4





Future Production Rates





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 PDC.





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.





Hydrocarbon Prices





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.





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 were supplied by Petroleum Development Corporation and are based on the operating expense reports of Petroleum Development Corporation 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.   No deduction was made for loan repayments, interest expenses, and exploration and development prepayments that are not charged directly to the leases or wells.





Development costs were furnished to us by Petroleum Development Corporation and are based on authorizations for expenditure for the proposed work or actual costs for similar projects. The estimates of the net abandonment costs furnished by PDC were accepted without independent verification.  Ryder Scott has not performed a detailed study of the abandonment costs or the salvage value and makes no warranty for Petroleum Development Corporation’s estimate.





Because of the direct relationship between volumes of proved undeveloped reserves and development plans, we include in the proved undeveloped category only reserves assigned to undeveloped locations that we have been assured will definitely be drilled.   PDC has assured us of their intent and ability to proceed with the development activities included in this report, and that they are not aware of any legal, regulatory or political obstacles that would significantly alter their plans.


Petroleum Development Corporation
 March 5, 2010
 Page 5




Current costs 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 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.





Ryder Scott requires that staff engineers and geoscientists have received professional accreditation, and are maintaining in good standing, 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 prior to becoming an officer of the Company.





We are independent petroleum engineers with respect to PDC.  Neither we nor any of 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 professional qualifications of the undersigned, the technical person primarily responsible for reviewing and approving the reserves information discussed in this report, are included as an attachment to this letter.


Petroleum Development Corporation
 March 5, 2010
 Page 6


Terms of Usage





This report was prepared for the exclusive use and sole benefit of Petroleum Development Corporation’s PDC RR06LP Partnership 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/ Larry T. NelmsLarry T. Nelms, P.E.Managing Senior Vice President