exv5w1

Exhibit 5.1


		ATTORNEYS AT LAW 777 EAST WISCONSIN AVENUE MILWAUKEE, WI 53202-5306 414.271.2400 TEL 414.297.4900 FAX foley.com

January 29, 2009		CLIENT/MATTER NUMBER
		038584-0123

Whiting Petroleum Corporation
1700 Broadway, Suite 2300
Denver, CO 80290

Ladies and Gentlemen:

We have acted as counsel for Whiting Petroleum Corporation, a Delaware corporation (the “Company”), in conjunction with the preparation of a Registration Statement on Form S-3 (Registration No. 333-133889) (the “Registration Statement”), including the prospectus constituting a part thereof, dated May 8, 2006, and the prospectus supplement, dated January 29, 2009 (collectively, the “Prospectus”), filed by the Company with the Securities and Exchange Commission under the Securities Act of 1933, as amended (the “Securities Act”), relating to the issuance and sale of (i) 8,000,000 shares of the Company’s common stock, $0.001 par value (the “Common Stock”), and related Preferred Share Purchase Rights (the “Rights”) in a public offering and (ii) up to 1,200,000 additional shares of Common Stock and related Rights pursuant to the over-allotment option granted by the Company to the underwriters for such public offering (the shares of Common Stock and related Rights described in clause (i) and (ii) are collectively referred to as the “Offering Shares”) in the manner set forth in the Prospectus. The terms of the Rights are set forth in that certain Rights Agreement, dated as of February 23, 2006, between the Company and Computershare Trust Company, Inc. (the “Rights Agreement”).

In connection with our representation, we have examined: (i) the Registration Statement, including the Prospectus; (ii) the Company’s Amended and Restated Certificate of Incorporation and Amended and Restated By-Laws, as amended to date; (iii) the Rights Agreement; (iv) resolutions of the Company’s Board of Directors and the action of the Special Offering Committee of the Board of Directors relating to the authorization of the issuance of the Offering Shares and accompanying Rights subject to the Registration Statement; and (v) such other proceedings, documents and records as we have deemed necessary to enable us to render this opinion.

Based upon the foregoing, we are of the opinion that:

1. The Company is a corporation duly incorporated and validly existing under the laws of the State of Delaware.

2. The Offering Shares covered by the Registration Statement, when issued and paid for in the manner contemplated in the Registration Statement and the Prospectus, will be validly issued, fully paid and nonassessable.


BOSTON	JACKSONVILLE	NEW YORK	SAN FRANCISCO	TOKYO
BRUSSELS	LOS ANGELES	ORLANDO	SHANGHAI	WASHINGTON, D.C.
CENTURY CITY	MADISON	SACRAMENTO	SILICON VALLEY
CHICAGO	MIAMI	SAN DIEGO	TALLAHASSEE
DETROIT	MILWAUKEE	SAN DIEGO/DEL MAR	TAMPA