PURCHASE A GREEMENT dated September 18, 2009

Exhibit 10.1

EXECUTION VERSION

Continental Resources, Inc.

Banner Pipeline Company, L.L.C.

$300,000,000

8.250% Senior Notes due 2019

PURCHASE A GREEMENT

dated September 18, 2009

Banc of America Securities LLC

RBS Securities Inc.

Wells Fargo Securities, LLC

PURCHASE AGREEMENT

September 18, 2009

B ANC OF A MERICA S ECURITIES LLC

RBS S ECURITIES I NC .

W ELLS F ARGO S ECURITIES , LLC

As Representatives of the Initial Purchasers

c/o Banc of America Securities LLC

One Bryant Park

New York, New York 10036

Ladies and Gentlemen:

Introductory . Continental Resources, Inc., an Oklahoma corporation (the “Company”), proposes to issue and sell to the several Initial Purchasers named in Schedule A (the “Initial Purchasers”), acting severally and not jointly, the respective amounts set forth in such Schedule A of $300,000,000 aggregate principal amount of the Company’s 8.250% Senior Notes due 2019 (the “Notes”). Banc of America Securities LLC, RBS Securities Inc. and Wells Fargo Securities, LLC have agreed to act as the representatives of the several Initial Purchasers (the “Representatives”) in connection with the offering and sale of the Notes.

The Notes will be issued pursuant to an indenture, to be dated as of September 23, 2009 (the “Indenture”), among the Company, the Initial Guarantor (as defined below) and Wilmington Trust FSB, as trustee (the “Trustee”). Notes will be issued only in book-entry form in the name of Cede & Co., as nominee of The Depository Trust Company (the “Depositary”) pursuant to a letter of representations, to be dated on or before the Closing Date (as defined in Section 2 hereof) (the “DTC Agreement”), between the Company and the Depositary.

The holders of the Notes will be entitled to the benefits of a registration rights agreement, to be dated as of the Closing Date (the “Registration Rights Agreement”), among the Company, the Initial Guarantor and the Initial Purchasers, pursuant to which the Company and the Initial Guarantor may be required to file with the Commission (as defined below), under the circumstances set forth therein, (i) a registration statement under the Securities Act (as defined below) relating to another series of debt securities of the Company with terms substantially identical to the Notes (the “Exchange Notes”) and the Guarantors’ (as defined below) Exchange Guarantees (the “Exchange Guarantees”) to be offered in exchange for the Notes and the Guarantees (as defined below) (the “Exchange Offer”) and (ii) a shelf registration statement pursuant to Rule 415 of the Securities Act relating to the resale by certain holders of the Notes, and in each case, to use their commercially reasonable efforts to cause such registration statements to be declared effective. All references herein to the Exchange Notes and the Exchange Offer are only applicable if the Company and the Initial Guarantor are in fact required to consummate the Exchange Offer pursuant to the terms of the Registration Rights Agreement.

The payment of principal of, premium, if any, and interest on the Notes and the Exchange Notes when and as the same becomes due and payable, will be fully and unconditionally guaranteed on a senior unsecured basis, jointly and severally by (i) Banner Pipeline Company, L.L.C., the Company’s sole direct or indirect subsidiary (the “Initial Guarantor”) and (ii) any subsidiary of the Company formed or acquired after the Closing Date that executes a supplement to the Indenture guaranteeing the Notes in accordance with the terms of the Indenture, and their respective successors and assigns (together with the Initial Guarantor, the “Guarantors”), pursuant to their guarantees (the “Guarantees”). The Notes and the Guarantees related thereto are herein collectively referred to as the “Securities”; and the Exchange Notes and the Guarantees related thereto are herein collectively referred to as the “Exchange Securities.”

Each of the Company and the Initial Guarantor understands that the Initial Purchasers propose to make an offering of the Securities on the terms and in the manner set forth herein and in the Pricing Disclosure Package (as defined below) and agrees that the Initial Purchasers may resell, subject to the conditions set forth herein, all or a portion of the Securities to purchasers (the “Subsequent Purchasers”) on the terms set forth in the Pricing Disclosure Package (the first time when sales of the Securities are made is referred to as the “Time of Sale”). The Securities are to be offered and sold to or through the Initial Purchasers without being registered with the Securities and Exchange Commission (the “Commission”) under the Securities Act of 1933 (as amended, the “Securities Act,” which term, as used herein, includes the rules and regulations of the Commission promulgated thereunder), in reliance upon exemptions therefrom. Pursuant to the terms of the Securities and the Indenture, investors who acquire Securities shall be deemed to have agreed that Securities may only be resold or otherwise transferred, after the date hereof, if such Securities are registered for sale under the Securities Act or if an exemption from the registration requirements of the Securities Act is available (including the exemptions afforded by Rule 144A under the Securities Act (“Rule 144A”) or Regulation S under the Securities Act (“Regulation S”)).

The Company has prepared and delivered to each Initial Purchaser copies of a Preliminary Offering Memorandum, dated September 14, 2009 (the “Preliminary Offering Memorandum”), and has prepared and delivered to each Initial Purchaser copies of a Pricing Supplement, dated September 18, 2009 in the form attached hereto as Annex II (the “Pricing Supplement”), describing the terms of the Securities, each for use by such Initial Purchaser in connection with its solicitation of offers to purchase the Securities. The Preliminary Offering Memorandum and the Pricing Supplement are herein referred to as the “Pricing Disclosure Package.” Promptly after this Agreement is executed and delivered, the Company will prepare and deliver to each Initial Purchaser a final offering memorandum dated the date hereof (the “Final Offering Memorandum”).

All references herein to the terms “Pricing Disclosure Package” and “Final Offering Memorandum” shall be deemed to mean and include all information filed under the Securities Exchange Act of 1934 (as amended, the “Exchange Act,” which term, as used herein, includes the rules and regulations of the Commission promulgated thereunder) prior to the Time of Sale and incorporated by reference in the Pricing Disclosure Package (including the Preliminary Offering Memorandum) or the Final Offering Memorandum (as the case may be), and all references herein to the terms “amend,” “amendment” or “supplement” with respect to the Final Offering Memorandum shall be deemed to mean and include all information filed under the Exchange Act after the Time of Sale and incorporated by reference in the Final Offering Memorandum.

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The Company and the Initial Guarantor each hereby confirms its agreements with the Initial Purchasers as follows:

SECTION 1. Representations and Warranties. Each of the Company and the Initial Guarantor, jointly and severally, hereby represents, warrants and covenants to each Initial Purchaser that, as of the date hereof and as of the Closing Date (references in this Section 1 to the “Offering Memorandum” are to (x) the Pricing Disclosure Package in the case of representations and warranties made as of the date hereof and (y) the Final Offering Memorandum in the case of representations and warranties made as of the Closing Date):

(a) No Registration Required. Subject to compliance by the Initial Purchasers with the representations and warranties set forth in Section 2 hereof and with the procedures set forth in Section 7 hereof, it is not necessary in connection with the offer, sale and delivery of the Securities to the Initial Purchasers and to each Subsequent Purchaser in the manner contemplated by this Agreement and the Offering Memorandum to register the Securities under the Securities Act or, until such time as the Exchange Securities are issued pursuant to an effective registration statement, to qualify the Indenture under the Trust Indenture Act of 1939, as amended (the “Trust Indenture Act,” which term, as used herein, includes the rules and regulations of the Commission promulgated thereunder).

(b) No Integration of Offerings or General Solicitation. None of the Company, its affiliates (as such term is defined in Rule 501 under the Securities Act) (each, an “Affiliate”), or any person acting on its or any of their behalf (other than the Initial Purchasers and their Affiliates as to whom the Company makes no representation or warranty) has, directly or indirectly, solicited any offer to buy or offered to sell, or will, directly or indirectly, solicit any offer to buy or offer to sell, in the United States or to any United States citizen or resident, any security which is or would be integrated with the sale of the Securities in a manner that would require the Securities to be registered under the Securities Act. None of the Company, its Affiliates, or any person acting on its or any of their behalf (other than the Initial Purchasers and their Affiliates, as to whom the Company makes no representation or warranty) has engaged or will engage, in connection with the offering of the Securities, in any form of general solicitation or general advertising within the meaning of Rule 502 under the Securities Act. With respect to those Securities sold in reliance upon Regulation S, (i) none of the Company, its Affiliates or any person acting on its or their behalf (other than the Initial Purchasers and their Affiliates, as to whom the Company makes no representation or warranty) has engaged or will engage in any directed selling efforts within the meaning of Regulation S and (ii) each of the Company and its Affiliates and any person acting on its or their behalf (other than the Initial Purchasers and their Affiliates, as to whom the Company makes no representation or warranty) has complied and will comply with the offering restrictions set forth in Regulation S.

(c) Eligibility for Resale under Rule 144A. When issued on the Closing Date, the Securities will be eligible for resale pursuant to Rule 144A and will not be of the same class as securities listed on a national securities exchange registered under Section 6 of the Exchange Act or quoted in a U.S. automated inter-dealer quotation system.

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(d) The Pricing Disclosure Package and Offering Memorandum. Neither the Pricing Disclosure Package, as of the Time of Sale, nor the Final Offering Memorandum, as of its date or (as amended or supplemented in accordance with Section 3(a), as applicable) as of the Closing Date, contains or will contain an untrue statement of a material fact or omits or will omit to state a material fact necessary in order to make the statements therein, in the light of the circumstances under which they were made, not misleading; provided that this representation, warranty and agreement shall not apply to statements in or omissions from the Pricing Disclosure Package, the Final Offering Memorandum or any amendment or supplement thereto made in reliance upon and in conformity with information furnished to the Company in writing by any Initial Purchaser through the Representatives expressly for use in the Pricing Disclosure Package, the Final Offering Memorandum or amendment or supplement thereto, as the case may be. The Pricing Disclosure Package contains, and the Final Offering Memorandum will contain, all the information specified in, and meeting the requirements of, Rule 144A. The Company has not distributed and will not distribute, prior to the later of the Closing Date and the completion of the Initial Purchasers’ distribution of the Securities, any offering material in connection with the offering and sale of the Securities other than the Pricing Disclosure Package and the Final Offering Memorandum.

(e) Company Additional Written Communications . The Company has not prepared, made, used, authorized, approved or distributed and will not prepare, make, use, authorize, approve or distribute any written communication that constitutes an offer to sell or solicitation of an offer to buy the Securities (each such communication by the Company or its agents and representatives (other than a communication referred to in clauses (i) and (ii) below) a “Company Additional Written Communication”) other than (i) the Pricing Disclosure Package, (ii) the Final Offering Memorandum, and (iii) any electronic road show or other written communications, in each case used in accordance with Section 3(a). Each such Company Additional Written Communication, when taken together with the Pricing Disclosure Package, did not, and at the Closing Date will not, contain any untrue statement of a material fact or omit to state a material fact necessary in order to make the statements therein, in the light of the circumstances under which they were made, not misleading; provided that this representation, warranty and agreement shall not apply to statements in or omissions from each such Company Additional Written Communication made in reliance upon and in conformity with information furnished to the Company in writing by any Initial Purchaser through the Representatives expressly for use in any Company Additional Written Communication.

(f) Incorporated Documents. The documents incorporated or deemed to be incorporated by reference in the Offering Memorandum at the time they were or hereafter are filed with the Commission (collectively, the “Incorporated Documents”) complied and will comply in all material respects with the requirements of the Exchange Act.

(g) The Purchase Agreement. This Agreement has been duly authorized, executed and delivered by, and is a valid and binding agreement of, the Company and the Initial Guarantor.

(h) The Registration Rights Agreement and DTC Agreement. Each of the Registration Rights Agreement and the DTC Agreement has been duly authorized and, on the Closing Date, will have been duly executed and delivered by, and, assuming the due

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authorization, execution and delivery thereof by the other parties thereto, each such agreement will constitute a valid and binding agreement of, the Company and, in the case of the Registration Rights Agreement, the Initial Guarantor, enforceable in accordance with its terms, except as the enforcement thereof may be limited by bankruptcy, insolvency, reorganization, moratorium or other similar laws relating to or affecting the rights and remedies of creditors or by general equitable principles (regardless of whether enforcement is considered in a proceeding in equity or at law) and except as rights to indemnification under the Registration Rights Agreement may be limited by applicable law.

(i) Authorization of the Securities and the Exchange Securities. The Notes to be purchased by the Initial Purchasers from the Company are substantially in the form contemplated by the Indenture, have been duly authorized for issuance and sale pursuant to this Agreement and the Indenture and, at the Closing Date, will have been duly executed by the Company and, when issued and authenticated by the Trustee in the manner provided for in the Indenture and delivered against payment of the purchase price therefor, will constitute valid and binding agreements of the Company, enforceable against the Company in accordance with their terms, except as the enforcement thereof may be limited by bankruptcy, insolvency, reorganization, moratorium or other similar laws relating to or affecting the rights and remedies of creditors or by general equitable principles (regardless of whether enforcement is considered in a proceeding in equity or at law) and will be entitled to the benefits of the Indenture. The Exchange Notes have been duly and validly authorized for issuance by the Company, and if and when issued and authenticated by the Trustee in accordance with the terms of the Indenture and delivered in the Exchange Offer contemplated by the Registration Rights Agreement, will constitute valid and binding obligations of the Company, enforceable against the Company in accordance with their terms, except as the enforcement thereof may be limited by bankruptcy, insolvency, reorganization, moratorium, or similar laws relating to or affecting enforcement of the rights and remedies of creditors or by general equitable principles (regardless of whether enforcement is considered in a proceeding in equity or at law) and will be entitled to the benefits of the Indenture. The Initial Guarantor has duly authorized the Guarantees and, when the Indenture has been duly authorized, executed and delivered by the Company and the Trustee and the Notes have been issued and authenticated in the manner provided for in the Indenture and delivered against payment of the purchase price therefor, the Guarantees will constitute valid and binding agreements of the Initial Guarantor, enforceable against the Initial Guarantor in accordance with their terms, except as the enforcement thereof may be limited by bankruptcy, insolvency, reorganization, moratorium or other similar laws relating to or affecting the rights and remedies of creditors or by general equitable principles (regardless of whether enforcement is considered in a proceeding in equity or at law). The Initial Guarantor has duly authorized the Exchange Guarantees and, when the Indenture has been duly authorized, executed and delivered by the Initial Guarantor and the Exchange Notes have been issued and authenticated in the manner provided for in the Indenture and delivered in the Exchange Offer contemplated by the Registration Rights Agreement, the Exchange Guarantees will constitute valid and binding agreements of the Initial Guarantor, enforceable against the Initial Guarantor in accordance with their terms, except as the enforcement thereof may be limited by bankruptcy, insolvency, reorganization, moratorium or other similar laws relating to or affecting the rights and remedies of creditors or by general equitable principles (regardless of whether enforcement is considered in a proceeding in equity or at law).

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(j) Authorization of the Indenture. The Indenture has been duly authorized by the Company and the Initial Guarantor and, at the Closing Date, will have been duly executed and delivered by the Company and the Initial Guarantor and, assuming the due authorization, execution and delivery thereof by the trustee, will constitute a valid and binding agreement of the Company and the Initial Guarantor, enforceable against the Company and the Initial Guarantor in accordance with its terms, except as the enforcement thereof may be limited by bankruptcy, insolvency, reorganization, moratorium or other similar laws relating to or affecting the rights and remedies of creditors or by general equitable principles (regardless of whether enforcement is considered in a proceeding in equity or at law).

(k) Description of the Securities and the Indenture. The Securities, the Exchange Securities and the Indenture will conform in all material respects to the respective statements relating thereto contained in the Offering Memorandum.

(l) No Material Adverse Change. Since the date of the most recent financial statements of the Company included or incorporated by reference in the Offering Memorandum, except in each case as otherwise disclosed in the Offering Memorandum: (i) there has not been any change in the capital stock, or material change in the long-term debt, of the Company or the Initial Guarantor, or any dividend or distribution of any kind declared, set aside for payment, paid or made by the Company on any class of capital stock, or any material adverse change, or any development involving a prospective material adverse change, in or affecting the business, properties, management, financial position, shareholders’ equity, results of operations or prospects of the Company and the Initial Guarantor, taken as a whole (any such change is called a “Material Adverse Change”); (ii) neither the Company nor the Initial Guarantor has entered into any transaction or agreement that is material to the Company and the Initial Guarantor, taken as a whole, or incurred any liability or obligation, direct or contingent, that is material to the Company and the Initial Guarantor, taken as a whole; and (iii) neither the Company nor the Initial Guarantor has sustained any material loss or interference with its business from fire, explosion, flood or other calamity, whether or not covered by insurance, or from any labor disturbance or dispute or any action, order or decree of any court or arbitrator or governmental or regulatory authority.

(m) Independent Accountants. Grant Thornton LLP, which expressed its opinion with respect to the financial statements (which term as used in this Agreement includes the related notes thereto) and supporting schedules filed with the Commission and included in the Offering Memorandum are independent public or certified public accountants within the meaning of Regulation S-X under the Securities Act and the Exchange Act, and any non-audit services provided by Grant Thornton LLP to the Company or the Initial Guarantor have been approved by the Audit Committee of the Board of Directors of the Company.

(n) Preparation of the Financial Statements. The financial statements, together with the related schedules and notes, included in the Offering Memorandum present fairly the consolidated financial position of the entities to which they relate as of and at the dates indicated and the results of their operations and cash flows for the periods specified. Such financial statements have been prepared in conformity with generally accepted accounting principles applied on a consistent basis throughout the periods involved, except as may be expressly stated in the related notes thereto. The audited financial data set forth in the Offering Memorandum

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under the captions “Summary—Summary Historical Consolidated Financial Data” and “Selected Historical Consolidated Financial Data” fairly present the information set forth therein on a basis consistent with that of the Company’s audited financial statements. The unaudited financial data set forth in the Offering Memorandum under the captions “Summary—Summary Historical Consolidated Financial Data” and “Selected Historical Consolidated Financial Data” fairly present the information set forth therein on a basis consistent with that of the Company’s unaudited financial statements contained in the Offering Memorandum. The pro forma financial information and the related notes thereto included in the Offering Memorandum give effect to assumptions made on a reasonable basis as set forth in the Offering Memorandum.

(o) Organization and Good Standing. Each of the Company and the Initial Guarantor has been duly organized and is validly existing and in good standing under the laws of its jurisdiction of organization, is duly qualified to do business and is in good standing in each jurisdiction in which its ownership or lease of property or the conduct of its businesses requires such qualification, and has all power and authority necessary to own or hold its properties and to conduct the businesses in which it is engaged, except where the failure to be so qualified or have such power or authority would not, individually or in the aggregate, have a material adverse effect on the business, properties, management, financial condition, shareholders’ equity, results of operations, cash flows or prospects of the Company and the Initial Guarantor taken as a whole or on the transactions contemplated hereby (a “Material Adverse Effect”). The Company does not own or control, directly or indirectly, any corporation, association or other entity other than the Initial Guarantor, and the Initial Guarantor is the only subsidiary of the Company.

(p) Non-Contravention of Existing Instruments; No Further Authorizations or Approvals Required. Neither the Company nor the Initial Guarantor is in violation of its charter or bylaws or similar organizational documents or is in default (or, with the giving of notice or lapse of time, would be in default) (“Default”) under any indenture, mortgage, loan or credit agreement, note, contract, franchise, lease or other instrument to which the Company or the Initial Guarantor is a party or by which it may be bound (including, without limitation, the Company’s Sixth Amended and Restated Credit Agreement, as amended, among the Company, the lenders party thereto from time to time and Union Bank of California, N.A., as administrative agent and as issuing lender, dated April 12, 2006), or to which any of the property or assets of the Company or the Initial Guarantor is subject (each, an “Existing Instrument”), except for such Defaults as would not, individually or in the aggregate, result in a Material Adverse Effect. The Company’s and the Initial Guarantor’s execution, delivery and performance of this Agreement, the Registration Rights Agreement, the DTC Agreement and the Indenture, and the issuance and delivery of the Securities or the Exchange Securities, and consummation of the transactions contemplated hereby and thereby and by the Offering Memorandum (i) will not result in any violation of the provisions of the charter or bylaws or similar organizational documents of the Company or the Initial Guarantor, (ii) will not conflict with or constitute a breach of, or Default under, or result in the creation or imposition of any lien, charge or encumbrance upon any property or assets of the Company or the Initial Guarantor pursuant to any Existing Instrument and (iii) will not result in any violation of any law, administrative regulation or administrative or court decree applicable to the Company or the Initial Guarantor, except, in the case of clauses (ii) and (iii) above, for such conflicts, breaches, Defaults, liens, charges, encumbrances or violations as would not, individually or in the aggregate, result in a Material Adverse Effect. Assuming the accuracy of the representations, warranties and covenants of the Initial Purchasers set forth

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herein, no consent, approval, authorization or other order of, or registration or filing with, any court or other governmental or regulatory authority or agency, is required for the Company’s and the Initial Guarantor’s execution, delivery and performance of this Agreement, the Registration Rights Agreement, the DTC Agreement or the Indenture, or the issuance and delivery of the Securities or the Exchange Securities, or consummation of the transactions contemplated hereby and thereby and by the Offering Memorandum, except such as may be required by the Securities Act or the securities laws of the several states of the United States with respect to the Company’s and the Initial Guarantor’s obligations under the Registration Rights Agreement or which, if not obtained or made, would not, individually or in the aggregate have a Material Adverse Effect.

(q) Legal Proceedings. Except as described in the Offering Memorandum, there are no legal, governmental or regulatory investigations, actions, suits or proceedings pending to which the Company or the Initial Guarantor is or may be a party or to which any property of the Company or the Initial Guarantor is or may be the subject that, individually or in the aggregate, if determined adversely to the Company or the Initial Guarantor, could reasonably be expected to have a Material Adverse Effect or materially and adversely affect the ability of the Company or the Initial Guarantor to perform its obligations under this Agreement; to the knowledge of the Company, no such investigations, actions, suits or proceedings are threatened or contemplated by any governmental or regulatory authority or others; and (i) there are no current or pending legal, governmental or regulatory actions, suits or proceedings that are required by the Exchange Act to be disclosed in an annual report on Form 10-K which are not so disclosed in the Offering Memorandum and (ii) there are no statutes, regulations or contracts or other documents that are required by the Exchange Act to be disclosed in an annual report on Form 10-K which are not so disclosed in the Offering Memorandum.

(r) Licenses and Permits . The Company and the Initial Guarantor possess all licenses, certificates, permits and other authorizations issued by, and have made all declarations and filings with, the appropriate federal, state, local or foreign governmental or regulatory authorities that are necessary for the ownership or lease of their respective properties or the conduct of their respective businesses as described in the Offering Memorandum, except where the failure to possess or make the same would not, individually or in the aggregate, have a Material Adverse Effect; and except as described in the Offering Memorandum, or as would not, individually or in the aggregate, have a Material Adverse Effect, neither the Company nor the Initial Guarantor has received notice of any revocation or modification of any such license, certificate, permit or authorization or has any reason to believe that any such license, certificate, permit or authorization will not be renewed in the ordinary course.

(s) Title to Real and Personal Property. Each of the Company and the Initial Guarantor has good and marketable title to all real and other property owned by it, in each case free and clear of all liens, encumbrances and defects except those (i) described in the Offering Memorandum or (ii) that would not, individually or in the aggregate, have a Material Adverse Effect. Except as described in the Offering Memorandum, each of the Company and the Initial Guarantor holds all leased real and other property under valid and enforceable leases, with such exceptions as would not have a Material Adverse Effect.

(t) Taxes . The Company and the Initial Guarantor have paid all federal, state, local and foreign taxes and filed all tax returns required to be paid or filed through the date hereof; and

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except as otherwise disclosed in the Offering Memorandum, or as would not, individually or in the aggregate, have a Material Adverse Effect, there is no tax deficiency that has been, or could reasonably be expected to be, asserted against the Company or the Initial Guarantor or any of their respective properties or assets.

(u) Investment Company Act . Each of the Company and the Initial Guarantor is not and, after giving effect to the offering and sale of the Securities and the application of the proceeds thereof as described in the Offering Memorandum, will not be required to register as an “investment company” or an entity “controlled” by an “investment company” within the meaning of the Investment Company Act of 1940, as amended, and the rules and regulations of the Commission thereunder (collectively, “Investment Company Act”).

(v) Insurance. The Company and the Initial Guarantor have insurance covering their respective properties, operations, personnel and businesses, which insurance is in amounts and insures against such losses and risks as are adequate to protect the Company and the Initial Guarantor and their respective businesses; and neither the Company nor the Initial Guarantor has (i) received notice from any insurer or agent of such insurer that capital improvements or other expenditures are required or necessary to be made in order to continue such insurance or (ii) any reason to believe that it will not be able to renew its existing insurance coverage as and when such coverage expires or to obtain similar coverage at reasonable cost from similar insurers as may be necessary to continue its business.

(w) No Labor Disputes . No labor disturbance by or dispute with employees of the Company or the Initial Guarantor exists or, to the knowledge of the Company, is contemplated or threatened; and the Company is not aware of any existing or imminent labor disturbance by, or dispute with, the employees of any of its or the Initial Guarantor’s principal suppliers, contractors or customers, except as would not have a Material Adverse Effect.

(x) No Restrictions on Subsidiary . No subsidiary of the Company is currently prohibited, directly or indirectly, under any agreement or other instrument to which it is a party or is subject, from paying any dividends to the Company, from making any other distribution on such subsidiary’s capital stock, from repaying to the Company any loans or advances to such subsidiary from the Company or from transferring any of such subsidiary’s properties or assets to the Company.

(y) Forward-Looking Statements . No forward-looking statement (within the meaning of Section 27A of the Securities Act and Section 21E of the Exchange Act) contained in the Offering Memorandum has been made or reaffirmed without a reasonable basis or has been disclosed other than in good faith.

(z) Statistical and Market Data . Nothing has come to the attention of the Company that has caused the Company to believe that the statistical and market-related data included in the Offering Memorandum is not based on or derived from sources that are reliable and accurate in all material respects.

(aa) No Price Stabilization or Manipulation. None of the Company or the Initial Guarantor has taken and or will take, directly or indirectly, any action designed to or that might be reasonably expected to cause or result in stabilization or manipulation of the price of any security of the Company to facilitate the sale or resale of the Securities.

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(bb) Sarbanes-Oxley Act . There is and has been no failure on the part of the Company, the Initial Guarantor or any of their respective directors or officers, in their capacities as such, to comply with any applicable provision of the Sarbanes-Oxley Act of 2002 and any applicable rules and regulations promulgated in connection therewith, including Section 402 relating to loans and Sections 302 and 906 relating to certifications.

(cc) Accounting Controls . The Company and the Initial Guarantor maintain a system of “internal control over financial reporting” (as defined in Rule 13a-15(f) of the Exchange Act) that comply with the requirements of the Exchange Act and have been designed by, or under the supervision of, the Company’s principal executive and principal financial officers, and effected by the Company’s board of directors, management and other personnel, to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles, including those policies and procedures that (i) pertain to the maintenance of records that in reasonable detail accurately and fairly reflect the transactions and dispositions of the assets of the Company; (ii) provide reasonable assurance that transactions are recorded as necessary to permit preparation of financial statements in accordance with generally accepted accounting principles, and that receipts and expenditures of the Company are being made only in accordance with authorizations of management and directors of the Company; and (iii) provide reasonable assurance regarding prevention or timely detection of unauthorized acquisition, use or disposition of the Company’s assets that could have a material effect on the Company’s financial statements.

(dd) Disclosure Controls . The Company and the Initial Guarantor maintain an effective system of “disclosure controls and procedures” (as defined in Rule 13a-15(e) of the Exchange Act) that is designed to ensure that information required to be disclosed by the Company in reports that it files or submits under the Exchange Act is recorded, processed, summarized and reported within the time periods specified in the Commission’s rules and forms, including controls and procedures designed to ensure that such information is accumulated and communicated to the Company’s management as appropriate to allow timely decisions regarding required disclosure.

(ee) Compliance with Environmental Laws. (i) The Company and the Initial Guarantor (x) are in compliance with any and all applicable federal, state, local and foreign laws (including common law), rules, regulations, requirements, decisions and orders relating to the protection of human health and safety, the environment or hazardous or toxic substances or wastes, pollutants or contaminants (collectively, “Environmental Laws”); (y) have received and are in compliance with all permits, licenses, certificates or other authorizations or approvals required of them under applicable Environmental Laws (collectively “Environmental Permits”) to conduct their respective businesses; and (z) except as described in the Offering Memorandum, have not received any notice or claim relating to Environmental Laws, including, without limitation, any notice or claim of any actual or potential liability for the investigation or remediation of any hazardous or toxic substances or wastes, pollutants or contaminants, and (ii) there are no costs or liabilities (whether accrued, contingent, absolute, determined, determinable

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or otherwise) associated with Environmental Laws or Environmental Permits, including, without limitation, any capital or operating expenditures required for cleanup, closure of properties or compliance with Environmental Laws or Environmental Permits, any related constraints on operating activities and any potential liabilities to third parties, of or relating to the Company or the Initial Guarantor, except in the case of each of (i) and (ii) above, for any such failure to comply, or failure to receive required Environmental Permits, or cost or liability, as would not, individually or in the aggregate, have a Material Adverse Effect.

(ff) Compliance With ERISA . Each employee benefit plan, within the meaning of Section 3(3) of the Employee Retirement Income Security Act of 1974, as amended (“ERISA”), that is maintained, administered or contributed to by the Company or any of its affiliates for employees or former employees of the Company and its affiliates has been maintained in compliance, in all material respects, with its terms and the requirements of any applicable statutes, orders, rules and regulations, including but not limited to ERISA and the Internal Revenue Code of 1986, as amended (the “Code”); no prohibited transaction, within the meaning of Section 406 of ERISA or Section 4975 of the Code, has occurred with respect to any such plan excluding any transactions effected pursuant to a statutory or administrative exemption and transactions which, individually or in the aggregate, would not have a Material Adverse Effect; and no such plan is subject to the funding rules of Section 412 of the Code or Section 302 of ERISA.

(gg) Related Party Transactions . No relationship, direct or indirect, exists between or among the Company or the Initial Guarantor, on the one hand, and the directors, officers, shareholders, customers or suppliers of the Company or the Initial Guarantor, on the other, that is required by the Exchange Act to be disclosed in an annual report on Form 10-K which is not so disclosed in the Offering Memorandum.

(hh) No Conflict with Money Laundering Laws . The operations of the Company and its subsidiaries are and have been conducted at all times in compliance with applicable financial recordkeeping and reporting requirements of the Currency and Foreign Transactions Reporting Act of 1970, as amended, the money laundering statutes of all applicable jurisdictions, the rules and regulations thereunder and any related or similar rules, regulations or guidelines issued, administered or enforced by any governmental agency (collectively, the “Money Laundering Laws”) and no action, suit or proceeding by or before any court or governmental agency, authority or body or any arbitrator involving the Company or any of its subsidiaries with respect to the Money Laundering Laws is pending or, to the best knowledge of the Company, threatened.

(ii) Reserve Data. (i) The oil and natural gas reserve estimates of the Company and its subsidiary as of December 31, 2006, 2007 and 2008 contained in the Offering Memorandum are derived from reports that have been prepared by, or have been audited by, Ryder Scott Company, LP, as set forth and to the extent indicated therein, and (ii) such estimates fairly reflect the oil and natural gas reserves of the Company and its subsidiary, as applicable, at the dates indicated therein and are in accordance, in all material respects, with Commission guidelines applied on a consistent basis throughout the periods involved.

(jj) Independent Petroleum Engineers . Ryder Scott Company, LP have represented to the Company that they are, and the Company believes them to be, independent petroleum engineers with respect to the Company and for the periods set forth in the Offering Memorandum.

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Any certificate signed by an officer of the Company or the Initial Guarantor and delivered to the Initial Purchasers or to counsel for the Initial Purchasers shall be deemed to be a representation and warranty by the Company or the Initial Guarantor to each Initial Purchaser as to the matters set forth therein.

SECTION 2. Purchase, Sale and Delivery of the Securities .

(a) The Securities. Each of the Company and the Initial Guarantor agrees to issue and sell to the Initial Purchasers, all of the Securities, and the Initial Purchasers agree, severally and not jointly, to purchase from the Company and the Initial Guarantor the aggregate principal amount of Securities set forth opposite their names on Schedule A, at a purchase price of 96.910% of the principal amount thereof payable on the Closing Date, in each case, on the basis of the representations, warranties and agreements herein contained, and upon the terms, subject to the conditions thereto, herein set forth.

(b) The Closing Date. Delivery of certificates for the Securities in definitive global form to be purchased by the Initial Purchasers and payment therefor shall be made at the offices of Davis Polk & Wardwell LLP, 450 Lexington Avenue, New York, New York (or such other place as may be agreed to by the Company and the Representatives) at 9:00 a.m. New York City time, on September 23, 2009, or such other time and date as the Representatives shall designate by notice to the Company (the time and date of such closing are called the “Closing Date”). The Company hereby acknowledges that circumstances under which the Representatives may provide notice to postpone the Closing Date as originally scheduled include, but are in no way limited to, any determination by the Company or the Initial Purchasers to re-circulate to investors copies of an amended or supplemented Offering Memorandum or a delay as contemplated by the provisions of Section 17 hereof.

(c) Delivery of the Securities. The Company shall deliver, or cause to be delivered, the Securities to the Representatives for the accounts of the several Initial Purchasers through the facilities of the Depositary on the Closing Date against the irrevocable release of a wire transfer of immediately available funds for the amount of the purchase price therefor. The certificates for the Securities shall be in such denominations and registered in the name of Cede & Co., as nominee of the Depositary, pursuant to the DTC Agreement, and shall be made available for inspection on the business day preceding the Closing Date at a location in New York City, as the Representatives may designate. Time shall be of the essence, and delivery at the time and place specified in this Agreement is a further condition to the obligations of the Initial Purchasers.

(d) Initial Purchasers as Qualified Institutional Buyers. Each Initial Purchaser severally and not jointly represents and warrants to, and agrees with, the Company that it is a “qualified institutional buyer” within the meaning of Rule 144A (a “Qualified Institutional Buyer”).

SECTION 3. Additional Covenants. Each of the Company and the Initial Guarantor further covenants and agrees with each Initial Purchaser as follows:

(a) Preparation of Final Offering Memorandum; Initial Purchasers’ Review of Proposed Amendments and Supplements and Company Additional Written Communications. As promptly as practicable following the Time of Sale and in any event not later than the second business day following the date hereof, the Company will prepare and deliver to the Initial Purchasers the Final Offering Memorandum, which shall consist of the Preliminary Offering Memorandum as modified only by the information contained in the Pricing Supplement. The Company will not amend or supplement the Preliminary Offering Memorandum or the Pricing Supplement. The Company will not amend or supplement the Final Offering Memorandum prior to the Closing Date unless the Representatives shall previously have been furnished a copy of the proposed amendment or supplement at least two business days prior to the proposed use or filing, and shall not have objected to such amendment or supplement. Before making, preparing, using, authorizing, approving or distributing any Company Additional Written Communication, the Company will furnish to the Representatives a copy of such written communication for review and will not make, prepare, use, authorize, approve or distribute any such written communication to which the Representatives reasonably object.

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(b) Amendments and Supplements to the Final Offering Memorandum and Other Securities Act Matters. If, prior to the later of (x) the Closing Date and (y) the completion of the placement of the Securities by the Initial Purchasers with the Subsequent Purchasers, any event shall occur or condition exist as a result of which it is necessary to amend or supplement the Final Offering Memorandum, as then amended or supplemented, in order to make the statements therein, in the light of the circumstances when the Final Offering Memorandum is delivered to a Subsequent Purchaser, not misleading, or if in the judgment of the Representatives or counsel for the Initial Purchasers it is otherwise necessary to amend or supplement the Final Offering Memorandum to comply with law, the Company agrees to promptly prepare (subject to Section 3 hereof), furnish at its own expense to the Initial Purchasers, amendments or supplements to the Final Offering Memorandum so that the statements in the Final Offering Memorandum as so amended or supplemented will not, in the light of the circumstances at the Closing Date and at the time of sale of Securities, be misleading or so that the Final Offering Memorandum, as amended or supplemented, will comply with all applicable law.

(c) Copies of the Offering Memorandum. The Company agrees to furnish the Initial Purchasers, without charge, as many copies of the Pricing Disclosure Package and the Final Offering Memorandum and any amendments and supplements thereto as they shall reasonably request.

(d) Blue Sky Compliance. Each of the Company and the Initial Guarantor shall cooperate with the Representatives and counsel for the Initial Purchasers to qualify or register (or to obtain exemptions from qualifying or registering) all or any part of the Securities for offer and sale under the securities laws of the several states of the United States, the provinces of Canada or any other jurisdictions designated by the Representatives, shall comply with such laws and shall continue such qualifications, registrations and exemptions in effect so long as required for the distribution of the Securities. None of the Company or Initial Guarantor shall be required to qualify as a foreign corporation or to take any action that would subject it to general service of process in any such jurisdiction where it is not presently qualified or where it would be subject to taxation as a foreign corporation. The Company will advise the Representatives promptly of the suspension of the qualification or registration of (or any such exemption relating to) the

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Securities for offering, sale or trading in any jurisdiction or any initiation or threat of any proceeding for any such purpose, and in the event of the issuance of any order suspending such qualification, registration or exemption, each of the Company and the Initial Guarantor shall use its commercially reasonable efforts to obtain the withdrawal thereof at the earliest possible moment.

(e) Use of Proceeds. The Company shall apply the net proceeds from the sale of the Securities sold by it in the manner described under the caption “Use of Proceeds” in the Pricing Disclosure Package.

(f) The Depositary. The Company will cooperate with the Initial Purchasers and use its commercially reasonable efforts to permit the Securities to be eligible for clearance and settlement through the facilities of the Depositary.

(g) Additional Issuer Information. Prior to the completion of the placement of the Securities by the Initial Purchasers with the Subsequent Purchasers, the Company shall file, on a timely basis, with the Commission and the New York Stock Exchange (the “NYSE”) all reports and documents required to be filed under Section 13 or 15 of the Exchange Act. Additionally, at any time when the Company is not subject to Section 13 or 15 of the Exchange Act, for the benefit of holders and beneficial owners from time to time of the Securities, the Company shall furnish, at its expense, upon request, to holders and beneficial owners of Securities and prospective purchasers of Securities information (“Additional Issuer Information”) satisfying the requirements of Rule 144A(d).

(h) Agreement Not To Offer or Sell Additional Securities. During the period of 45 days following the date hereof, the Company will not, without the prior written consent of Banc of America Securities LLC (which consent may be withheld at the sole discretion of Banc of America Securities LLC), directly or indirectly, sell, offer, contract or grant any option to sell, pledge, transfer or establish an open “put equivalent position” within the meaning of Rule 16a-1 under the Exchange Act, or otherwise dispose of or transfer, or announce the offering of, or file any registration statement under the Securities Act in respect of, any debt securities of the Company or securities exchangeable for or convertible into debt securities of the Company (other than as contemplated by this Agreement and to register the Exchange Securities). For the avoidance