MEMBERSHIP INTEREST ASSIGNMENT AGREEMENT

EXHIBIT 10.13

MEMBERSHIP INTEREST ASSIGNMENT AGREEMENT

This Membership Interest Assignment Agreement (“ Assignment ”) is entered into this 30th day of March, 2006 (“ Execution Date ”), but to be effective as between the parties as of January 1, 2006 (“ Effective Date ”), by and between Continental Resources, Inc., an Oklahoma corporation (“ Buyer ”), and the Harold Hamm Revocable Inter-Vivos Trust dated April 23, 1984, Harold Hamm, Trustee; the Harold Hamm HJ Trust, Bert Mackie, Trustee; and the Harold Hamm DST Trust, Bert Mackie, Trustee (individually, the “ Seller ” and collectively, the “ Sellers ”), the record and beneficial owners of all of the issued and outstanding membership interest (the “ Interests ”) of Banner Pipeline Company, LLC, an Oklahoma limited liability company (the “Company”), and Harold Hamm, a lender to the Company and the Seller’s (“ Lender ”) with reference to the following circumstances:

A. Sellers own the Interests, which comprises all of the issued and outstanding membership interests of the Company;

B. Sellers desire to sell the Interests to Buyer and Buyer desires to purchase the Interests from Sellers; and

C. Immediately prior to the transactions contemplated by this Assignment, the Company has transferred and assigned to Banner Transportation Company, LLC (“ Newco ”) all of its assets and liabilities relating to the gas gathering system under construction in Richland County, Montana (“ Gathering Assets ”), leaving Company with only the assets and liabilities related to its crude oil marketing business.

In consideration of the premises and the mutual promises contained herein, the parties agree as follows:

1. Assignment and Loan Repayment . As of the Effective Date, Sellers hereby assign and transfer to Buyer, in exchange for the aggregate payment of $5,272,513.94 (the “ Purchase Price ”), receipt of which is hereby acknowledged, all of Sellers’ right, title and interest in the Interests. The Purchase Price is calculated as follows:

The amount of the Purchase Price for each Seller shall be equal to a percentage of the Purchase Price equal to their Percentage ownership of the Company as set forth on the signature page. Each Seller hereby authorizes the Buyer to pay the Purchase Price to Lender to reimburse him for prior advances made to each Seller to fund the Sellers’ capital contributions (or a portion thereof). In addition, Buyer shall, on behalf of the Company, simultaneously pay to Lender $3,500,000, plus any accrued interest ($50,054.79), representing the amount of a loan from

Lender to the Company and Lender hereby acknowledges receipt of such amount and agrees that the Company shall have no further liability with respect to such loan.

Total proceeds paid to Lender and Sellers are equal to the Purchase Price ($5,272,513.94) plus loan proceeds ($3,550, 054.79) or $8,822,568.73.

2. Representations and Warranties of Sellers . Each Seller hereby represents and warrants to Buyer that:

2.1 No Violation or Conflict by Seller; Consents . The execution, delivery and performance of this Assignment do not and will not (a) conflict with or violate any law, judgment, order or decree binding on such Seller or (b) constitute a violation or breach of any contract or agreement to which such Seller is a party or by which it is bound. No notice to, filing or registration with, or authorization, consent or approval of, any person is necessary or is required to be made or obtained by such Seller in connection with the execution, delivery and performance by such Seller of this Assignment.

2.2 Title to Interests . Seller owns of record and beneficially good, valid and marketable title to the Interests set forth opposite its name on the signature page, and Buyer will have title to the Interests free and clear of any and all mortgages, liens, encumbrances, charges, claims, restrictions, pledges, security interests or impositions, good and valid title to the Interests, free and clear of all mortgages, liens, encumbrances, charges, claims, restrictions, pledges, security interests or impositions.

2.3 Organization and Authority of the Company . The Company is duly organized, validly existing and in good standing under the laws of the State of Oklahoma. The Company has full power to carry on its business as it is now being conducted and to own, operate and hold under lease its assets and properties as, and in the places where, such properties and assets now are owned, operated or held. The Company is duly qualified as a foreign entity to do business, and is in good standing, in each jurisdiction where the failure to be so qualified would have a material adverse effect.

2.4 Capitalization . The Interests represents all of the issued and outstanding membership interests of the Company and were not issued in violation of any preemptive or other right. There are no options, warrants or other rights to subscribe for or purchase any membership interest of the Company or securities convertible into or exchangeable for, or which otherwise confer on the holder any right to acquire, any membership interest of the Company, nor is the Company or any Seller committed to issue any such option, warrant or other right.

2.5 No Violation or Conflict by the Company; Consents . The execution, delivery and performance of this Assignment do not and will not (a) conflict with or violate any law, judgment, order or decree binding on the Company or the Articles of Organization or Operating Agreement of the Company or (b) constitute a violation or breach of any contract, or result in any party having the right to cancel, terminate, modify or exercise any option under any of the contracts to which the Company is a party or otherwise bound. No notice to, filing or registration with, or authorization, consent or approval of,

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any person is necessary or is required to be made or obtained by the Company in connection with the consummation of the transactions contemplated in this Assignment.

2.6 Marketing Activities . The Company has, prior to the Effective Date, purchased crude oil from the Buyer and resold it to unrelated third parties.

3. Representations and Warranties of Buyer . Buyer hereby represents and warrants to Sellers that:

3.1 Organization . Buyer is a corporation duly organized, validly existing and in good standing under the laws of the State of Oklahoma and has full power to enter into this Assignment and to perform its obligations hereunder.

3.2 Authorization . The execution, delivery and performance by Buyer of this Assignment, and of all of the documents and instruments required hereby from Buyer, are within the power of Buyer and have been duly authorized by all necessary action of Buyer.

3.3 No Violation or Conflict by Buyer . The execution, delivery and performance of this Assignment by Buyer do not and will not (a) conflict with or violate any law, judgment, order or decree binding on Buyer or the Certificate of Incorporation or Bylaws of Buyer or (b) constitute a violation or breach of any contract or agreement to which Buyer is a party or by which it is bound. No notice to, filing or registration with, or authorization, consent or approval of, any person is necessary or is required to be made or obtained by Buyer in connection with the execution and delivery and performance by Buyer of this Assignment.

4. Indemnities And Additional Covenants

4.1 Sellers’ Indemnity .

(a) Each Seller hereby, jointly and severably, indemnifies and holds Buyer, the Company and their respective affiliates (collectively, the “ Indemnified Parties ”) harmless from and against, and agrees to defend promptly the Indemnified Parties from and reimburse the Indemnified Parties for, any and all losses, damages, costs, expenses, liabilities, obligations and claims of any kind, including, without limitation, any tax cost or reduction in any loss