Exhibit 99.1

Whiting Petroleum Corporation Announces Notice to Trustee of Redemption of 7.0% Senior Subordinated Notes Due 2014

DENVER – September 23, 2013 – Whiting Petroleum Corporation (NYSE: WLL) today announced it notified the trustee under the indenture governing its $250 million aggregate principal amount of 7.0% Senior Subordinated Notes due 2014 to provide notice to holders of the notes on October 1, 2013 that it elected to redeem the notes on October 31, 2013. The redemption price will equal 100% of the principal amount thereof plus the make-whole redemption premium described in the indenture plus accrued and unpaid interest up to but not including the redemption date.

Whiting intends to finance the redemption of the notes with the proceeds from its offering of $1.9 billion of senior notes that closed on September 12, 2013. As a result of the redemption of the notes, Whiting expects to make a cash payment of $4.1 million related to the estimated make-whole redemption premium, exclusive of accrued and unpaid interest, and to incur a non-cash charge of $0.4 million related to unamortized debt issuance costs, which will result in a reduction in retained earnings of $4.5 million on a pre-tax basis.

About Whiting Petroleum Corporation

Whiting Petroleum Corporation, a Delaware corporation, is an independent oil and gas company that explores for, develops, acquires and produces crude oil, natural gas and natural gas liquids primarily in the Rocky Mountain, Permian Basin, Mid-Continent, Michigan and Gulf Coast regions of the United States. The Company’s largest projects are in the Bakken and Three Forks plays in North Dakota and its Enhanced Oil Recovery field in Texas. The Company trades publicly under the symbol WLL on the New York Stock Exchange.

Forward-Looking Statements

This news release contains statements that we believe to be “forward-looking statements” within the meaning of Section 27A of the Securities Act of 1933 and Section 21E of the Securities Exchange Act of 1934. All statements other than historical facts, including, without limitation, statements regarding our future financial position, business strategy, projected revenues, earnings, costs, capital expenditures and debt levels, and plans and objectives of management for future operations, are forward-looking statements. When used in this news release, words such as we “expect,” “intend,” “plan,” “estimate,” “anticipate,” “believe” or “should” or the negative thereof or variations thereon or similar terminology are generally intended to identify forward-looking statements. Such forward-looking statements are subject to risks and uncertainties that could cause actual results to differ materially from those expressed in, or implied by, such statements.

These risks and uncertainties include, but are not limited to: declines in oil, natural gas liquids or natural gas prices; our level of success in exploration, development and production activities; adverse weather conditions that may negatively impact development or production activities; the timing of our exploration and development activities; our ability to obtain sufficient quantities of CO2 necessary to carry out our enhanced oil recovery projects; inaccuracies of our reserve estimates or our assumptions underlying them; revisions to reserve estimates as a result of changes in commodity prices; risks related to our level of indebtedness and periodic redeterminations of the borrowing base under our credit agreement; our ability to generate sufficient cash flows from operations to meet the internally funded portion of our capital expenditures budget; our ability to obtain external capital to finance exploration and development operations and acquisitions; federal and state initiatives relating to the regulation of hydraulic fracturing; the potential impact of federal debt reduction initiatives and tax reform legislation being considered by the U.S. Federal government that could have a negative effect on the oil and gas industry; our ability to identify and complete acquisitions and to successfully integrate acquired businesses; unforeseen underperformance of or liabilities associated with acquired properties, including the properties subject to the Williston Basin acquisition; our ability to successfully complete potential asset dispositions and the risks related thereto; the impacts of hedging on our results of operations; failure of our properties to yield oil or gas in commercially viable quantities; uninsured or underinsured losses resulting from our oil and gas operations; our inability to access oil and gas markets due to market conditions or operational impediments; the impact and costs of compliance with laws and regulations governing our oil and gas operations; our ability to replace our oil and natural gas reserves; any loss of our senior management or technical personnel; competition in the oil and gas industry in the regions in which we operate; risks arising out of our hedging transactions; and other risks described under the caption “Risk Factors” in our final prospectus supplement, dated September 9, 2013. We assume no obligation, and disclaim any duty, to update the forward-looking statements in this news release.

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