Exhibit 99.1

Oasis Petroleum Inc. Announces Quarter Ending June 30, 2012 Earnings

Houston, Texas — August 6, 2012 — Oasis Petroleum Inc. (NYSE: OAS) (“Oasis” or the “Company”) today announced financial results for the quarter ended June 30, 2012.

Highlights for the three months ended June 30, 2012 include:

“Our team continued to execute on our business plan and capitalize on the operational efficiencies and improvements from the first quarter, resulting in record average daily production of 20,353 Boepd,” said Thomas B. Nusz, Oasis’ Chairman and Chief Executive Officer. “Oasis completed and brought on production another 26 gross operated wells in the second quarter, matching our activity from the first quarter and exceeding our second quarter estimates of 22 to 24 completions. We believe our production will continue to grow in the second half of 2012, and based on our increased operating activity for the year, we are increasing our full year 2012 production guidance to 20,500 to 22,500 Boepd from 18,000 to 22,000 Boepd. We are positioning the Company for long-term success as we expand our infrastructure development efforts and execute on our well density testing and infill pilot programs in advance of our transition to full development mode in 2013. We are also starting to see a reduction in well costs as a result of operating efficiencies and lower service costs.”

“Additionally, our marketing team continues to leverage our third party oil gathering pipeline, as we have been able to optimize realizations by marketing approximately 60% of our operated volumes to both rail and pipeline delivery points off the gathering system rather than sales at the lease,” Mr. Nusz added. “Lastly, Oasis Well Services is progressing as scheduled and commenced 24 hour operations in June.”

Operational and Financial Update

Average daily production for the second quarter of 2012 was 20,353 Boepd, an increase of 158% as compared to 7,893 Boepd in the second quarter of 2011. Sequential quarter-over-quarter average daily production increased 2,720 Boepd, or 15%. In the second quarter of 2012, 91% of production was from oil. Average daily production by project area is listed in the following table:

The Company’s average price per barrel of oil, without realized derivatives, was $82.36 in the second quarter of 2012, compared to $95.48 in the second quarter of 2011 and $88.10 in the first quarter of 2012. The Company’s average price differential compared to West Texas Intermediate (“WTI”) crude oil index prices was 12% in the second quarter of 2012, compared to 7% in the second quarter of 2011 and 14% in the first quarter of 2012. The Company’s differentials improved in the second quarter of 2012 compared to the first quarter of 2012 due to higher quoted prices relative to WTI for Bakken crude in markets such as Clearbrook, Minnesota and Guernsey, Wyoming as a result of increased takeaway capacity from the Williston Basin and fewer refinery constraints.

Total revenue for the second quarter of 2012 was $149.1 million compared to $67.2 million for the second quarter of 2011, an increase of 122%. Sequential quarter-over-quarter revenue growth was $10.5 million, or 8%. This increase is primarily due to a 15% increase in production and a $3.2 million increase in well services revenues in the second quarter of 2012, offset by a 7% decrease in realized prices compared to the first quarter 2012.

The following table describes the Company’s drilling activity by project area in the Williston Basin as of June 30, 2012:

Lease operating expenses (“LOE”) per Boe decreased $1.80, or 22%, to $6.49 per Boe in the second quarter of 2012 compared to the second quarter of 2011, and increased $0.37 per Boe in the second quarter of 2012 compared to the first quarter of 2012. LOE trended up due to higher workover expenses incurred in the second quarter; however, this increase was partially offset by cost savings resulting from an increase in produced water volumes flowing through the Company’s salt water disposal systems.

Marketing, transportation and gathering expense per Boe was $1.06 in the second quarter of 2012 compared to $0.34 in the second quarter 2011 and $1.60 in the first quarter of 2012. The sequential quarter decrease is attributed to the $1.4 million cost for bulk oil purchases made in the first quarter. Excluding the bulk oil purchase in the first quarter of 2012, marketing, transportation and gathering per Boe would have been $0.74.  The 43% increase from the first to the second quarter of 2012 is due to higher operated volumes flowing through third party oil gathering pipelines. While transporting volumes through third party oil gathering pipelines increases marketing, transportation and gathering expenses, it improves oil price realizations by eliminating trucking costs, which are reflected in the oil price differential rather than as an expense.

Production taxes as a percent of oil and gas revenues were 9.5% in the second quarter of 2012, 10.5% in the second quarter of 2011, and 9.6% in the first quarter of 2012. The Company’s effective production tax rate decreased in the second quarter of 2012 primarily as a result of certain new wells in Montana subject to lower incentivized production tax rates.

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Depreciation, depletion and amortization expenses (“DD&A”) totaled $44.2 million in the second quarter of 2012, $13.1 million in the second quarter of 2011, and $38.9 million in the first quarter of 2012. DD&A was $23.87 per Boe in the second quarter of 2012, $18.24 per Boe in the second quarter of 2011, and $24.23 per Boe in the first quarter of 2012.

General and administrative expenses (“G&A”) totaled $13.5 million in the second quarter of 2012, $6.6 million in the second quarter of 2011, and $12.2 million in the first quarter of 2012. The increase in G&A expenses from the first quarter of 2012 to the second quarter of 2012 was primarily due to higher compensation costs from organizational growth. G&A expenses were $7.31 per Boe in the second quarter of 2012 ($6.71 per Boe for exploration and production (“E&P”) only), $9.21 per Boe in the second quarter of 2011, and $7.60 per Boe in the first quarter of 2012. Amortization of restricted stock-based compensation, which is included in the aggregate G&A expense, was $2.3 million, or $1.25 per Boe, in the second quarter of 2012, as compared to $1.0 million, or $1.45 per Boe, in the second quarter of 2011 and $1.6 million, or $0.99 per Boe, in the first quarter of 2012.

As a result of the Company’s derivative activities, it incurred net cash settlement losses of $1.2 million and $4.1 million in the second quarters of 2012 and 2011, respectively. In the first quarter of 2012, Oasis incurred a net cash settlement loss of $1.3 million. As a result of forward oil price changes, the Company recognized non-cash unrealized mark-to-market net derivative gains of $75.8 million and $31.7 million for the second quarters of 2012 and 2011, respectively. Oasis recognized a non-cash unrealized mark-to-market net derivative loss of $17.3 million in the first quarter of 2012.

The Company recorded non-cash charges for the impairment of oil and natural gas properties of $2.2 million in the second quarter of 2012 related to unproved property leases that expired during the period or have been forecasted to expire under current drilling plans, as compared to $1.5 million in the second quarter of 2011 and $0.4 million in the first quarter of 2012.

Interest expense increased $7.3 million to $14.1 million for the second quarter of 2012 compared to the second quarter of 2011 and increased $0.2 million compared to the first quarter of 2012. The $7.3 million increase was the result of additional interest expense from the Company’s issuance of 6.5% senior unsecured notes in November of 2011.

Income tax expense was $45.4 million for the three months ended June 30, 2012, resulting in an effective tax rate of 37.4%. The Company’s income tax expense for the three months ended June 30, 2011 was recorded at 37.8% of pre-tax net income. The Company’s effective tax rate is expected to continue to closely approximate the statutory rate applicable to the U.S. and the blended state rate of the states in which the Company conducts business.

Adjusted EBITDA for the second quarter of 2012 was $108.5 million, an increase of $63.9 million, or 143%, over the second quarter of 2011 of $44.6 million, and a 7% increase over the first quarter of 2012 of $101.1 million. For a definition of Adjusted EBITDA and a reconciliation of Adjusted EBITDA to net income (loss) and net cash provided by operating activities, see “Non-GAAP Financial Measure” below.

The Company reported net income of $76.0 million, or $0.82 per weighted average diluted share, for the second quarter of 2012 as compared to net income of $33.3 million, or $0.36 per weighted average diluted share, for the second quarter of 2011 and net income of $16.4 million, or $0.18 per weighted average diluted share, for the first quarter of 2012.

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Capital Expenditures

Oasis’ E&P capital expenditures were $263.2 million for the second quarter of 2012 and $530.2 million year to date. The following table depicts the Company’s E&P capital expenditures by project area and total capital expenditures by category for the first and second quarters of 2012:

Liquidity

On June 30, 2012, Oasis had total cash and cash equivalents of $238.9 million and had no outstanding indebtedness under its revolving credit facility with a $500 million borrowing base. On July 2, 2012, the Company received $392 million in net proceeds from its issuance of $400 million in aggregate principal amount of 6.875% senior unsecured notes due 2023. The Company’s lenders waived the mandatory reduction of the Company’s borrowing base that otherwise would have occurred as a result of the issuance of the senior unsecured notes.

Outlook for 2012

Oasis is providing an updated outlook for 2012. On July 26, 2012, the Company’s Board of Directors increased the total 2012 capital expenditure budget from $884 million to $1,062 million.

The increase in the development capital budget is primarily due to accelerated activity in both operated wells (additional gross operated wells and increased working interest in operated wells) and non-operated wells. The increase in development capital is partially offset by anticipated reductions in well costs related to both service and proppant costs. The Company has also updated its wells spud by area, as shown below:

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Oasis also increased its infrastructure budget by $17 million, as the Company continues to improve LOE through its investment in salt water disposal projects. In addition to the increased capital expenditure budget, Oasis is also providing updated guidance on operational metrics, including a lower range for LOE, as follows:

“Our continued production growth has been enhanced by an increase in both gross operated and total net wells,” said Mr. Nusz. “Our Board of Directors increased our 2012 CapEx budget due to higher working interest and accelerated activity, which has a proportionate increase to our capital production. With the increased operational performance from both our drilling rigs and frac crews, Oasis now expects to be able to spud 112 gross operated wells and turn to production a similar number of wells while running nine to ten rigs for the remainder of the year and utilizing two to three frac spreads. With all of the great work our team has been doing operationally and working constructively with our service providers on cost structure, we believe that we will be able to decrease overall well costs by approximately 10% by year-end 2012. We expect additional savings will arise from pad drilling, further decreasing costs, especially in 2013.”

Hedging Activity

As of August 6, 2012, the Company had the following outstanding commodity derivative contracts, all of which are priced off of NYMEX WTI and settle monthly:

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Conference Call Information

Investors, analysts and other interested parties are invited to listen to the Company’s conference call:

A recording of the conference call will be available beginning at 11:00 a.m. Central Time on the day of the call and will be available until Tuesday, August 14, 2012 by dialing:

The conference call will also be available for replay for approximately 30 days at www.oasispetroleum.com.

Forward-Looking Statements

This press release contains 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 statements of historical facts, included in this press release that address activities, events or developments that the Company expects, believes or anticipates will or may occur in the future are forward-looking statements. Without limiting the generality of the foregoing, forward-looking statements contained in this press release specifically include the expectations of plans, strategies, objectives and anticipated financial and operating results of the Company, including the Company’s drilling program, production, derivative instruments, capital expenditure levels and other guidance included in this press release. These statements are based on certain assumptions made by the Company based on management’s experience and perception of historical trends, current conditions, anticipated future developments and other factors believed to be appropriate. Such statements are subject to a number of assumptions, risks and uncertainties, many of which are beyond the control of the Company, which may cause actual results to differ materially from those implied or expressed by the forward-looking statements. These include, but are not limited to, changes in oil and natural gas prices, weather and environmental conditions, the timing of planned capital expenditures, availability of acquisitions, uncertainties in estimating proved reserves and forecasting production

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results, operational factors affecting the commencement or maintenance of producing wells, the condition of the capital markets generally, as well as the Company’s ability to access them, the proximity to and capacity of transportation facilities, and uncertainties regarding environmental regulations or litigation and other legal or regulatory developments affecting the Company’s business and other important factors that could cause actual results to differ materially from those projected as described in the Company’s reports filed with the SEC.

Any forward-looking statement speaks only as of the date on which such statement is made and the Company undertakes no obligation to correct or update any forward-looking statement, whether as a result of new information, future events or otherwise, except as required by applicable law.

About Oasis Petroleum Inc.

Oasis is an independent exploration and production company focused on the acquisition and development of unconventional oil and natural gas resources, primarily operating in the Williston Basin. For more information, please visit the Company’s website at www.oasispetroleum.com.

Contact:

Oasis Petroleum Inc.

Richard Robuck, (281) 404-9600

Director – Finance

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Oasis Petroleum Inc. Financial Statements

Oasis Petroleum Inc.

Condensed Consolidated Balance Sheet

(Unaudited)

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Oasis Petroleum Inc.

Condensed Consolidated Statement of Operations

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Oasis Petroleum Inc.

Selected Financial and Operational Statistics

(Unaudited)

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Oasis Petroleum Inc.

Condensed Consolidated Statement of Cash Flows

(Unaudited)