SIXTH AMENDMENT TO AMENDED AND RESTATED CREDIT AGREEMENT

SIXTH AMENDMENT TO AMENDED AND RESTATED CREDIT AGREEMENT (this “ Amendment ”) is entered into as of May 22, 2009, by and among PETROLEUM DEVELOPMENT CORPORATION (the “ Borrower ”), CERTAIN SUBSIDIARIES OF THE BORROWER, as Guarantors (the “ Guarantors ”), the LENDERS party hereto (the “ Lenders ”) and JPMORGAN CHASE BANK, N.A., as Administrative Agent (the “ Administrative Agent ”).  Unless the context otherwise requires or unless otherwise expressly defined herein, capitalized terms used but not defined in this Amendment have the meanings assigned to such terms in the Credit Agreement (as defined below).

WHEREAS , the Borrower, the Guarantors, the Administrative Agent and the Lenders have entered into that certain Amended and Restated Credit Agreement dated as of November 4, 2005 (as the same has been and may hereafter be amended, restated, supplemented or otherwise modified from time to time, the “ Credit Agreement ”);

WHEREAS , the Borrower and the Guarantors have requested that the Administrative Agent and the Lenders amend the Credit Agreement (a) to extend the Maturity Date, (b) to permit the Borrower to incur additional unsecured Indebtedness, and (c) for certain other purposes as provided herein; and

WHEREAS , the Administrative Agent and the Lenders have agreed to amend the Credit Agreement as provided herein upon the terms and conditions set forth herein;

NOW, THEREFORE , for and in consideration of the mutual covenants and agreements herein contained and other good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged and confessed, the Borrower, the Guarantors, the Administrative Agent and the Lenders hereby agree as follows:

SECTION 1.   Amendments to Credit Agreement.   Subject to the satisfaction or waiver in writing of each condition precedent set forth in Section 4 of this Amendment, and in reliance on the representations, warranties, covenants and agreements contained in this Amendment, the Credit Agreement shall be amended in the manner provided in this Section 1 .

1.1   Additional Definitions.   Section 1.01 of the Credit Agreement shall be and it hereby is amended by inserting the following definitions in appropriate alphabetical order:

“ Allocated Partnership Volumes ” means, with respect to each Sponsored Partnership at any time, the volumes of Crude Oil and Natural Gas under any Swap Agreement then in effect allocated by Borrower to the Other Attributed Interests.

“ Co-Documentation Agent ” mean, so long as each such Person is a Lender, each Person identified as such on Schedule 2.01 .

“ Indenture ” means that certain Indenture dated as of February 8, 2008, by and between the Borrower, as issuer and The Bank of New York, as trustee, as amended and supplemented by the First Supplemental Indenture, dated as of February 8, 2008.

“ Limited Partnership Interests ” means any Equity Interests owned by any Person (other than any Credit Party) in any Sponsored Partnership.

“ Other Attributed Interests ” means any Oil and Gas Interests indirectly owned by any Person (other than any Credit Party) through the ownership of Limited Partnership Interests and attributed to such Person in proportion to such Person’s ownership of such Limited Partnership Interests.

“ Permitted Refinancing ” means any Senior Notes incurred or issued in exchange for, or the Net Cash Proceeds of which are used to extend, refinance, renew, replace, defease or refund, existing Senior Notes, in whole or in part, from time to time, but only to the extent the principal amount of such new Senior Notes (or if such new Senior Notes are issued at a discount, the initial issuance price of such new Senior Notes) does not, together with the principal amount outstanding of all other Senior Notes, exceed the amount permitted under Section 7.01(i) (plus the amount of any premiums paid and fees and expenses incurred in connection therewith).

“ Sixth Amendment Effective Date ” means May 22, 2009.

1.2   Amended Definitions.   The following definitions in Section 1.01 of the Credit Agreement shall be and they hereby are amended in their respective entireties to read as follows:

“ Aggregate Revolving Commitment ” means, as of the Sixth Amendment Effective Date, $350,000,000 and thereafter as such amount may be reduced or increased from time to time pursuant to Section 2.02 and Section 2.03 and as a result of changes in the Borrowing Base pursuant to Article III; provided that such amount shall not at any time exceed the lesser of (i) the Maximum Facility Amount and (ii) the Borrowing Base .   If at any time the Borrowing Base is reduced below the Aggregate Revolving Commitment, the Aggregate Revolving Commitment shall be reduced automatically to the amount of the Borrowing Base in effect at such time.

“ Applicable Rate ” means, with respect to any ABR Loan or Eurodollar Loan, or with respect to the Unused Commitment Fees payable hereunder, as the case may be, the applicable rate per annum set forth below under the caption “ABR Spread”, “Eurodollar Spread” or “Unused Commitment Fee Rate”, as the case may be, based upon the Borrowing Base Usage applicable on such date:

Each change in the Applicable Rate shall apply during the period commencing on the effective date of such change and ending on the date immediately preceding the effective date of the next change.

“ Lenders ” means the Persons listed on Schedule 2.01 and any other Person that shall have become a party hereto pursuant to an Assignment and Assumption or a Lender Certificate, other than any such Person that ceases to be a party hereto pursuant to an Assignment and Assumption.

“ Maturity Date ” means May 22, 2012.

“ Maximum Facility Amount ” means $500,000,000.

“ Net Cash Proceeds ” means, (i) with respect to the sale of Borrowing Base Properties (including Attributed Interests) by the Borrower or any Restricted Subsidiary (or Sponsored Partnership with respect to Attributed Interests), the excess, if any, of (a) the sum of cash and cash equivalents received in connection with such sale, but only as and when so received, over (b) the sum of (1) the principal amount of any Indebtedness that is secured by such asset and that is required to be repaid in connection with the sale thereof (other than the Loans), and (2) the out-of-pocket expenses incurred by the Borrower or such Restricted Subsidiary (or Sponsored Partnership with respect to Attributed Interests) in connection with such sale and (ii) with respect to any issuance of Senior Notes, the cash proceeds from such issuance of Senior Notes net of underwriting discounts and commissions and other reasonable costs and expenses associated therewith, including reasonable legal fees and expenses.

“ Redetermination Date ” means each date on which the Borrowing Base is redetermined pursuant to the terms hereof, which shall be (a) with respect to any Scheduled Redetermination, on or about May 15 and November 15 of each year, commencing November 15, 2005, (b) with respect to any Special Redetermination requested by the Borrower pursuant to Section 3.03, the first day of the first month which is not less than twenty (20) Business Days following the date of a request by the Borrower for a Special Redetermination and (c) with respect to any Special Redetermination requested by the Required Lenders, the date notice of such Redetermination is delivered to the Borrower pursuant to Section 3.05.

“ Senior Notes ” means (a) the 12% Senior Notes due 2018, issued pursuant to the Indenture, and (b) senior unsecured subordinated notes and senior unsecured notes issued after the Sixth Amendment Effective Date; provided that (i) the terms of such notes do not provide for any scheduled repayment, mandatory redemption or payment of a sinking fund obligation prior to the date that is six months after the Maturity Date, (ii) the covenant, default and remedy provisions of such notes are substantially the same as those set forth in the Indenture as in effect on the Sixth Amendment Effective Date, (iii) the mandatory prepayment, repurchase and redemption provisions of such notes are substantially the same as those set forth in the Indenture as in effect on the Sixth Amendment Effective Date, and (iv) the non-default interest rate on the outstanding principal balance of such notes does not exceed the prevailing market rate then in effect for similarly situated credits at the time such notes are issued.

“ Unrestricted Subsidiary ” means (a) any Subsidiary that at the time of determination shall be designated an Unrestricted Subsidiary by the  Board of Directors of the Borrower in the manner provided below and (b) any Subsidiary of an Unrestricted Subsidiary. The Board of Directors of the Borrower may designate any Subsidiary (including any newly acquired or newly formed Subsidiary) to be an Unrestricted Subsidiary unless such Subsidiary or any of its Subsidiaries (i) is a Material Domestic Subsidiary owning Oil and Gas Interests included in the Borrowing Base Properties or (ii) guarantees any indebtedness, liabilities, or other obligations under any now existing or hereafter outstanding Senior Notes.

1.3   Mandatory Prepayment of Loan.    Section 2.11 of the Credit Agreement shall be and it hereby is amended by (a) deleting the last sentence of clause (b) thereof in its entirety and (b) adding new clauses (c), (d) and (e) to read as follows:

(c)           In the event any Borrowing Base Deficiency occurs as a result of a reduction in the Borrowing Base pursuant to Section 3.07, the Borrower shall prepay the Loans with the Net Cash Proceeds received as a result of the issuance of such Senior Notes immediately upon receipt of such Net Cash Proceeds to the extent necessary to eliminate such Borrowing Base Deficiency after giving to such reduction in the Borrowing Base pursuant to Section 3.07.

(d)           Notwithstanding anything to the contrary contained in clauses (a), (b) and (c) of this Section 2.11, in the event the Aggregate Revolving Credit Exposure exceeds (i) the Maximum Facility Amount or (ii) the Aggregate Revolving Commitment at any time other than, with respect to this clause (ii), as a result of the occurrence of a Borrowing Base Deficiency to which neither Section 2.11(b) nor Section 2.11(c) apply, the Borrowers shall immediately prepay, subject to any funding indemnification amounts required by Section 2.16, the principal amount of the Loans to the extent necessary to eliminate such excess.

(e)             Amounts applied to the prepayment of Borrowings pursuant to this Section shall be first applied ratably to ABR Borrowings then outstanding and, upon payment in full of all outstanding ABR Borrowings, second, to Eurodollar Borrowings then outstanding, and if more than one Eurodollar Borrowing is then outstanding, to each such Eurodollar Borrowing beginning with the Eurodollar Borrowing with the least number of days remaining in the Interest Period applicable thereto and ending with the Eurodollar Borrowing with the most number of days remaining in the Interest Period applicable thereto. Any prepayments pursuant to this Section shall be accompanied by accrued interest to the extent required by Section 2.13 and any funding indemnification amounts required by Section 2.16.

1.4   Additional Reductions in Borrowing Base.   Section 3.07 of the Credit Agreement shall be and it hereby is amended and restated in its entirety to read as follows:

Section 3.07.                                 Additional Reductions in Borrowing Base .  Upon the issuance of any Senior Notes by any Credit Party (other than any Permitted Refinancing to the extent such Senior Notes are used to extend, refinance, renew, replace, defease or refund existing Senior Notes), the Borrowing Base then in effect shall automatically be reduced by $300 for each $1,000 in stated principal amount of such Senior Notes on the date such Senior Notes are issued.

1.5   Capitalization.   Section 4.13 of the Credit Agreement shall be and it hereby is amended and restated in its entirety to read as follows:

Section 4.13.                                 Capitalization .  Schedule 4.13 lists as of the Sixth Amendment Effective Date, (a) for the Borrower and each Restricted Subsidiary, its full legal name and its jurisdiction of organization, (b) for each Restricted Subsidiary, the number of shares of capital stock or other Equity Interests outstanding and the owner(s) of such shares or Equity Interests and (c) with respect to each Sponsored Partnership, the Partnership Interests owned by each Credit Party in such Sponsored Partnership.

1.6   Compliance Certificate.   Section 6.01(c) of the Credit Agreement shall be and it hereby is amended and restated in its entirety to read as follows:

(c)  concurrently with any delivery of financial statements under clause (a) or (b) above, a certificate in a form reasonably acceptable to Administrative Agent signed by a Financial Officer of the Borrower (i) certifying as to whether a Default has occurred and, if a Default has occurred, specifying the details thereof and any action taken or proposed to be taken with respect thereto, (ii) setting forth reasonably detailed calculations in a form reasonably acceptable to the Administrative Agent demonstrating compliance with clauses (x) and (y) of Section 7.05(a), (iii) setting forth, in a form reasonably acceptable to the Administrative Agent, the aggregate net amount of all unpaid holdback or reimbursement obligations of the Sponsored Partnerships to the Credit Parties with respect to all Allocated Partnership Volumes, taken as a whole, in the event such aggregate amount exceeds $5,000,000 as of the last day of any fiscal year of the Borrower with respect to the financial statements delivered under clause (a) above and as of the last day of any fiscal quarter of the Borrower with respect to the financial statements delivered under clause (b) above and (iv)  setting forth reasonably detailed calculations demonstrating compliance with Section 7.11.

1.7   Indebtedness.   Clause (i) of Section 7.01 of the Credit Agreement shall be and it hereby is amended and restated in its entirety to read as follows:

(i)           subject to any adjustment of the Borrowing Base required under Section 3.07 and any mandatory prepayment required under Section 2.11(c), unsecured Indebtedness under the Senior Notes in an aggregate principal amount not exceeding $450,000,000 and Permitted Refinancings of any such Indebtedness that does not cause the aggregate principal amount of the Senior Notes to exceed the maximum principal amount permitted under this clause (i) as of the date such Permitted Refinancing is consummated;

1.8   Swap Agreements.   Section 7.05 of the Credit Agreement shall be and it hereby is amended and restated in its entirety to read as follows:

Section 7.05.                                 Swap Agreements.   The Borrower will not, nor will the Borrower permit any of its Restricted Subsidiaries or any Sponsored Partnership to, enter into any Swap Agreement, except Swap Agreements entered into in the ordinary course of business and not for speculative purposes to:

(a) hedge or mitigate Crude Oil and Natural Gas price risks to which the Borrower, any Restricted Subsidiary or any Sponsored Partnership has actual exposure (whether or not treated as a hedge for accounting purposes under GAAP); provided that at the time the Borrower (whether on its own behalf or on behalf of any Sponsored Partnership), any Restricted Subsidiary or any Sponsored Partnership enters into any such Swap Agreement, such Swap Agreement when aggregated with all other Swap Agreements then in effect would not cause the aggregate notional volume per month for each of Crude Oil and Natural Gas, calculated separately, under all Swap Agreements then in effect (other than Swap Agreements that (i) are basis differential only swaps for volumes of Natural Gas included under other Swap Agreements permitted by this Section 7.05(a), (ii) are a hedge of volumes of Crude Oil or Natural Gas by means of a price “floor” for which there exists no deferred obligation to pay the related premium or other purchase price or the only deferred obligation is to pay the financing for such premium or other purchase price, or (iii) for purposes of determining compliance with clause (y) below, are volumes of Crude Oil and Natural Gas included in Allocated Partnership Volumes) to exceed, as of the date such Swap Agreement is executed, either (x) eighty percent (80%) of the “forecasted production from proved producing reserves” (as defined below) of the Borrower, the Restricted Subsidiaries, and the Sponsored Partnerships, taken as a whole, or (y) eighty percent (80%) of the “forecasted production from proved producing reserves” of the Borrower and the Restricted Subsidiaries (including the Attributed Interests), in each case, for any month during the forthcoming four year period; and

(b) effectively cap, collar or exchange interest rates (from fixed to floating rates, from one floating rate to another floating rate or otherwise) with respect to any interest-bearing liability or investment of any Credit Party.

As used in this Section 7.05, “forecasted production from proved producing reserves” means the forecasted production of each of Crude Oil and Natural Gas as reflected in the most recent Reserve Report delivered to the Administrative Agent pursuant to Section 6.01, after giving effect to (x) any pro forma adjustments for the consummation of any acquisitions or dispositions since the effective date of such Reserve Report and (y) any adjustments for changes in the forecasted production from proved producing reserves of Crude Oil and Natural Gas since delivery by the Borrower of the most recent Reserve Report based on the actual production of Crude Oil and Natural Gas set forth in any reports delivered to the Administrative Agent pursuant to Section 6.01(d) for the period specified therein and as calculated in accordance with Exhibit G attached hereto; provided that, in the case of clause (y) above, if such adjustments reflect an increase in the forecasted production from proved producing reserves of either Crude Oil or Natural Gas of more than fifteen percent (15%) of the forecasted production from proved producing reserves of Crude Oil or Natural Gas, as applicable, for the forthcoming five year period as reflected in the most recently delivered Reserve Report, then the Administrative Agent may, or at the direction of the Required Lenders shall, request and the Borrower shall deliver to the Administrative Agent and the Lenders within thirty (30) days after such request, an engineering analysis, on a month by month basis as to Crude Oil and Natural Gas separately, of the proved producing component of all New Production for the forthcoming five year period prepared by a petroleum engineer employed by the Borrower that confirms such increase in such forecasted production from such New Production and that is otherwise reasonably acceptable to the Administrative Agent. Each Credit Party and each Lender agrees and acknowledges that (i) the Existing Swap Agreements are Swap Agreements permitted under this Section 7.05, (ii) as of the Effective Date, the counterparty to such Swap Agreements is a L