For the quarterly period ended June 30, 2016

or

For the transition period from  to 

Commission file number: 1-34776

Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days.    Yes   ý     No   ¨

Indicate by check mark whether the registrant has submitted electronically and posted on its corporate Web site, if any, every Interactive Data File required to be submitted and posted pursuant to Rule 405 of Regulation S-T (§232.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submit and post such files).    Yes   ý     No   ¨

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, or a smaller reporting company. See the definitions of "large accelerated filer," "accelerated filer" and "smaller reporting company" in Rule 12b-2 of the Exchange Act.

Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act).    Yes   ¨      No   ý

Number of shares of the registrant's common stock outstanding at August 5, 2016 : 180,430,785 shares.

OASIS PETROLEUM INC.

FORM 10-Q

FOR THE QUARTER ENDED JUNE 30, 2016

TABLE OF CONTENTS

PART I - FINANCIAL INFORMATION

Item 1. - Financial Statements (Unaudited)

The accompanying notes are an integral part of these condensed consolidated financial statements.

Oasis Petroleum Inc.

Condensed Consolidated Statement of Operations

(Unaudited)

The accompanying notes are an integral part of these condensed consolidated financial statements.

Oasis Petroleum Inc.

Condensed Consolidated Statement of Changes in Stockholders' Equity

(Unaudited)

The accompanying notes are an integral part of these condensed consolidated financial statements.

Oasis Petroleum Inc.

Condensed Consolidated Statement of Cash Flows

(Unaudited)

The accompanying notes are an integral part of these condensed consolidated financial statements.

OASIS PETROLEUM INC.

Notes to Condensed Consolidated Financial Statements (Unaudited)

1. Organization and Operations of the Company

Oasis Petroleum Inc. (together with its consolidated subsidiaries, "Oasis" or the "Company") was originally formed in 2007 and was incorporated pursuant to the laws of the State of Delaware in 2010. The Company is an independent exploration and production company focused on the acquisition and development of unconventional oil and natural gas resources in the North Dakota and Montana regions of the Williston Basin. Oasis Petroleum North America LLC ("OPNA") conducts the Company's exploration and production activities and owns its proved and unproved oil and natural gas properties. The Company also operates a well services business through Oasis Well Services LLC ("OWS") and a midstream services business through Oasis Midstream Services LLC ("OMS"), both of which are separate reportable business segments that are complementary to its primary development and production activities.

2. Summary of Significant Accounting Policies

Basis of Presentation

The accompanying condensed consolidated financial statements of the Company include the accounts of Oasis and its wholly-owned subsidiaries. All significant intercompany transactions have been eliminated in consolidation. The accompanying condensed consolidated financial statements of the Company have not been audited by the Company's independent registered public accounting firm, except that the Condensed Consolidated Balance Sheet at December 31, 2015 is derived from audited financial statements. Certain reclassifications of prior year balances have been made to conform such amounts to current year classifications. These reclassifications have no impact on net income. In the opinion of management, all adjustments, consisting of normal recurring adjustments necessary for the fair statement, have been included. Management has made certain estimates and assumptions that affect reported amounts in the condensed consolidated financial statements and disclosures of contingencies. Actual results may differ from those estimates. The results for interim periods are not necessarily indicative of annual results.

These interim financial statements have been prepared pursuant to the rules and regulations of the Securities and Exchange Commission ("SEC") regarding interim financial reporting. Certain disclosures have been condensed or omitted from these financial statements. Accordingly, they do not include all of the information and notes required by accounting principles generally accepted in the United States of America ("GAAP") for complete consolidated financial statements and should be read in conjunction with the Company's audited consolidated financial statements and notes thereto included in the Company's Annual Report on Form 10-K for the year ended December 31, 2015 (" 2015 Annual Report").

Risks and Uncertainties

As an oil and natural gas producer, the Company's revenue, profitability and future growth are substantially dependent upon the prevailing and future prices for oil and natural gas, which are dependent upon numerous factors beyond its control such as economic, political and regulatory developments and competition from other energy sources. The energy markets have historically been very volatile, and there can be no assurance that oil and natural gas prices will not be subject to wide fluctuations in the future. Oil and natural gas prices have declined significantly since mid-2014. As a result of sustained lower commodity prices, the Company decreased its 2016 capital expenditures as compared to 2015 and continues to concentrate its drilling activities in certain areas that are the most economic in the Williston Basin. An extended period of low prices for oil and, to a lesser extent, natural gas could have a material adverse effect on the Company's financial position, results of operations, cash flows and quantities of oil and natural gas reserves that may be economically produced.

Significant Accounting Policies

There have been no material changes to the Company's critical accounting policies and estimates from those disclosed in the 2015 Annual Report.

Recent Accounting Pronouncements

Revenue recognition. In May 2014, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update No. 2014-09, Revenue from Contracts with Customers ("ASU 2014-09"). The objective of ASU 2014-09 is greater consistency and comparability across industries by using a five-step model to recognize revenue from customer contracts. ASU 2014-09 also contains some new disclosure requirements under GAAP. In August 2015, the FASB issued Accounting Standards Update No. 2015-14, Deferral of the Effective Date ("ASU 2015-14"). ASU 2015-14 defers the effective date of the new revenue standard by one year, making it effective for annual reporting periods beginning after December 15, 2017, including interim periods within that reporting period. In 2016, the FASB issued additional accounting standards updates to clarify the

implementation guidance of ASU 2014-09. The Company is currently evaluating the effect that adopting this guidance will have on its financial position, cash flows and results of operations.

Going concern. In August 2014, the FASB issued Accounting Standards Update No. 2014-15, Disclosure of Uncertainties about an Entity's Ability to Continue as a Going Concern ("ASU 2014-15"). ASU 2014-15 codifies in GAAP management's responsibility to evaluate whether there is substantial doubt about an entity's ability to continue as a going concern and to provide related footnote disclosures. ASU 2014-15 is effective for the annual reporting period ending after December 15, 2016 and for annual periods and interim periods thereafter. The adoption of this guidance will not impact the Company's financial position, cash flows or results of operations but could result in additional disclosures.

Inventory. In July 2015, the FASB issued Accounting Standards Update No. 2015-11, Simplifying the Measurement of Inventory ("ASU 2015-11"). ASU 2015-11 changes the inventory measurement principle from lower of cost or market to lower of cost and net realizable value for entities using the first-in, first-out (FIFO) or average cost methods. ASU 2015-11 is effective for fiscal years beginning after December 15, 2016, including interim periods within those years. The Company is currently evaluating the effect that adopting this guidance will have on its financial position, cash flows and results of operations.

Financial instruments. In January 2016, the FASB issued Accounting Standards Update No. 2016-01, Recognition and Measurement of Financial Assets and Financial Liabilities ("ASU 2016-01"), which requires that most equity instruments be measured at fair value with subsequent changes in fair value recognized in net income. ASU 2016-01 also impacts financial liabilities under the fair value option and the presentation and disclosure requirements for financial instruments. ASU 2016-01 does not apply to equity method investments or investments in consolidated subsidiaries. ASU 2016-01 is effective for fiscal years beginning after December 15, 2017, including interim periods within those years. The Company is currently evaluating the effect that adopting this guidance will have on its financial position, cash flows and results of operations.

Leases. In February 2016, the FASB issued Accounting Standards Update No. 2016-02, Leases ("ASU 2016-02"), which requires a lessee to recognize lease payment obligations and a corresponding right-of-use asset to be measured at fair value on the balance sheet. ASU 2016-02 also requires certain qualitative and quantitative disclosures about the amount, timing and uncertainty of cash flows arising from leases. ASU 2016-02 is effective for fiscal years beginning after December 15, 2018, including interim periods within those years. The Company is currently evaluating the effect that adopting this guidance will have on its financial position, cash flows and results of operations.

Embedded derivatives. In March 2016, the FASB issued Accounting Standards Update No. 2016-06, Contingent Put and Call Options in Debt Instruments ("ASU 2016-06"), which clarifies what steps are required when assessing whether the economic characteristics and risks of call (put) options are clearly and closely related to the economic characteristics and risks of their debt hosts, which is one of the criteria for bifurcating an embedded derivative. ASU 2016-06 is effective for fiscal years beginning after December 15, 2016, including interim periods within those years. The Company does not expect the adoption of this guidance to have a material impact on its financial position, cash flows or results of operations.

Stock-based compensation. In March 2016, the FASB issued Accounting Standards Update No. 2016-09, Improvements to Employee Share-Based Payment Accounting ("ASU 2016-09"), which updates several aspects of the accounting for share-based payment transactions, including recognition of excess tax benefits and deficiencies, the classification of those excess tax benefits on the statement of cash flows, an accounting policy election for forfeitures, the amount an employer can withhold to cover income taxes and still qualify for equity classification and the classification of those taxes paid on the statement of cash flows. ASU 2016-09 is effective for fiscal years beginning after December 15, 2016, including interim periods within those years. The Company is currently evaluating the effect that adopting this guidance will have on its financial position, cash flows and results of operations.

3. Inventory

Crude oil inventory includes oil in tank and linefill. Equipment and materials consist primarily of proppant, chemicals, tubular goods, well equipment to be used in future drilling or repair operations and well fracturing equipment. Inventory is stated at the lower of cost or market value with cost determined on an average cost method. Inventory consists of the following:

4. Fair Value Measurements

In accordance with the FASB's authoritative guidance on fair value measurements, the Company's financial assets and liabilities are measured at fair value on a recurring basis. The Company recognizes its non-financial assets and liabilities, such as asset retirement obligations ("ARO") and proved oil and natural gas properties upon impairment, at fair value on a non-recurring basis.

As defined in the authoritative guidance, fair value is the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date (exit price). To estimate fair value, the Company utilizes market data or assumptions that market participants would use in pricing the asset or liability, including assumptions about risk and the risks inherent in the inputs to the valuation technique. These inputs can be readily observable, market corroborated or generally unobservable.

The authoritative guidance establishes a fair value hierarchy that prioritizes the inputs used to measure fair value. The hierarchy gives the highest priority to unadjusted quoted prices in active markets for identical assets or liabilities ("Level 1" measurements) and the lowest priority to unobservable inputs ("Level 3" measurements). The three levels of the fair value hierarchy are as follows:

Level 1  - Unadjusted quoted prices are available in active markets for identical assets or liabilities as of the reporting date. Active markets are those in which transactions for the asset or liability occur in sufficient frequency and volume to provide pricing information on an ongoing basis.

Level 2  - Pricing inputs, other than unadjusted quoted prices in active markets included in Level 1, are either directly or indirectly observable as of the reporting date. Level 2 includes those financial instruments that are valued using models or other valuation methodologies. These models are primarily industry-standard models that consider various assumptions, including quoted forward prices for commodities, time value, volatility factors and current market and contractual prices for the underlying instruments, as well as other relevant economic measures. Substantially all of these assumptions are observable in the marketplace throughout the full term of the instrument and can be derived from observable data or are supported by observable levels at which transactions are executed in the marketplace.

Level 3  - Pricing inputs are generally less observable from objective sources, requiring internally developed valuation methodologies that result in management's best estimate of fair value.

Financial Assets and Liabilities

Financial assets and liabilities are classified in their entirety based on the lowest level of input that is significant to the fair value measurement. The Company's assessment of the significance of a particular input requires judgment and may affect the valuation of fair value assets and liabilities and their placement within the fair value hierarchy levels. The following tables set forth by level within the fair value hierarchy the Company's financial assets and liabilities that were accounted for at fair value on a recurring basis:

The Level 1 instruments presented in the tables above consist of money market funds included in cash and cash equivalents on the Company's Condensed Consolidated Balance Sheet at June 30, 2016 and December 31, 2015 . The Company's money market funds represent cash equivalents backed by the assets of high-quality major banks and financial institutions. The Company identifies the money market funds as Level 1 instruments because the money market funds have daily liquidity, quoted prices for the underlying investments can be obtained, and there are active markets for the underlying investments.

The Level 2 instruments presented in the tables above consist of commodity derivative instruments, which include oil collars and swaps. The fair values of the Company's commodity derivative instruments are based upon a third-party preparer's calculation using mark-to-market valuation reports provided by the Company's counterparties for monthly settlement purposes to determine the valuation of its derivative instruments. The Company has the third-party preparer evaluate other readily available market prices for its derivative contracts, as there is an active market for these contracts. The third-party preparer performs its independent valuation using a moment matching method similar to Turnbull-Wakeman for Asian options. The significant inputs used are crude oil prices, volatility, skew, discount rate and the contract terms of the derivative instruments. However, the Company does not have access to the specific proprietary valuation models or inputs used by its counterparties or third-party preparer. The Company compares the third-party preparer's valuation to counterparty valuation statements, investigating any significant differences, and analyzes monthly valuation changes in relation to movements in crude oil forward price curves. The determination of the fair value for derivative instruments also incorporates a credit adjustment for non-performance risk, as required by GAAP. The Company calculates the credit adjustment for derivatives in a net asset position using current credit default swap values for each counterparty. The credit adjustment for derivatives in a net liability position is based on the Company's market credit spread. Based on these calculations, the Company recorded an adjustment to reduce the fair value of its net derivative liability by $2.4 million at June 30, 2016 and an adjustment to reduce the fair value of its net derivative asset by $0.3 million at December 31, 2015 .

There were no transfers between fair value levels during the six months ended June 30, 2016 and 2015 .

Fair Value of Other Financial Instruments

The Company's financial instruments, including certain cash and cash equivalents, accounts receivable and accounts payable, are carried at cost, which approximates fair value due to the short-term maturity of these instruments. At June 30, 2016 , the Company's cash equivalents were all Level 1 assets.

The carrying amount of the Company's long-term debt reported in the Condensed Consolidated Balance Sheet at June 30, 2016 was $2,127.4 million , which included $2,123.4 million of senior unsecured notes, $35.0 million of borrowings under the revolving credit facility and a $31.0 million reduction for deferred financing costs on the senior unsecured notes (see Note 8 – Long-Term Debt). The fair value of the Company's senior unsecured notes, which are publicly traded and therefore categorized as Level 1 liabilities, was $1,965.2 million at June 30, 2016 .

Non-Financial Assets and Liabilities

Asset retirement obligations. The carrying amount of ARO in the Company's Condensed Consolidated Balance Sheet at June 30, 2016 was $37.1 million (see Note 9 – Asset Retirement Obligations). The Company determines its ARO by calculating the present value of estimated cash flows related to the liability. Estimating the future ARO requires management to make estimates and judgments regarding the timing and existence of a liability, as well as what constitutes adequate restoration when considering current regulatory requirements. Inherent in the fair value calculation are numerous assumptions and judgments, including the ultimate costs, inflation factors, credit adjusted discount rates, timing of settlement and changes in the legal, regulatory, environmental and political environments. These assumptions represent Level 3 inputs. To the extent future revisions to these assumptions impact the fair value of the existing ARO liability, a corresponding adjustment is made to the related asset.

Impairment. The Company reviews its proved oil and natural gas properties for impairment whenever events and circumstances indicate that a decline in the recoverability of their carrying value may have occurred. The Company estimates the expected undiscounted future cash flows of its proved oil and natural gas properties and then compares such undiscounted future cash flows to the carrying amount of the proved oil and natural gas properties to determine if the carrying amount is recoverable. If the carrying amount exceeds the estimated undiscounted future cash flows, the Company will adjust the carrying amount of the proved oil and natural gas properties to the fair value. The factors used to determine fair value are subject to management's judgment and expertise and include, but are not limited to, recent sales prices of comparable properties, the present value of future cash flows, net of estimated operating and development costs, using estimates of proved reserves, future commodity pricing, future production estimates, anticipated capital expenditures and various discount rates commensurate with the risk and current market conditions associated with realizing the expected cash flows projected. These assumptions represent Level 3 inputs.

On April 1, 2016, the Company sold certain proved oil and natural gas properties and other midstream properties (see Note 7 – Divestiture). For the six months ended June 30, 2016 , the Company recorded an impairment charge of $3.6 million , of which $2.4 million was included in its midstream services segment and $1.2 million was included in its exploration and production segment, to adjust the current carrying value of these assets, net of the associated ARO liabilities, to their estimated fair value. For the year ended December 31, 2015, the Company recorded an impairment charge of $9.4 million to adjust its net assets held for sale to their estimated fair value in its exploration and production segment. The fair value was determined based on the expected sales price, less costs to sell. No other impairment charges on proved oil and natural gas properties were recorded for the six months ended June 30, 2016 . No impairment charges on proved oil and natural gas properties were recorded for the three months ended June 30, 2016 and the three and six months ended June 30, 2015 .

In addition, as a result of expiring leases, the Company recorded non-cash impairment charges on its unproved oil and natural gas properties of $23,000 and $25,000 for the three and six months ended June 30, 2016 , respectively, and $0.4 million and $4.5 million for the three and six months ended June 30, 2015 , respectively. As a result of periodic assessments of unproved properties, the Company recorded non-cash impairment charges on its unproved oil and natural gas properties of $19.1 million and $20.3 million for the three and six months ended June 30, 2015 , respectively, related to acreage expiring in future periods because there were no current plans to drill or extend the leases prior to their expiration. For the three and six months ended June 30, 2016 , the Company did not record similar impairment charges.

5. Derivative Instruments

The Company utilizes derivative financial instruments to manage risks related to changes in oil prices. At June 30, 2016 , the Company utilized two-way and three-way costless collar options and swaps to reduce the volatility of oil prices on a significant portion of its future expected oil production. A two-way collar is a combination of options: a sold call and a purchased put. The purchased put establishes a minimum price (floor) and the sold call establishes a maximum price (ceiling) the Company will receive for the volumes under contract. A three-way collar is a combination of options: a sold call, a purchased put and a sold put. The purchased put establishes a minimum price (floor), unless the market price falls below the sold put (sub-floor), at which point the minimum price would be the NYMEX West Texas Intermediate crude oil index price ("WTI") plus the difference between the purchased put and the sold put strike price. The sold call establishes a maximum price (ceiling) the Company will receive for the volumes under contract. A swap is a sold call and a purchased put established at the same price (both ceiling and floor).

All derivative instruments are recorded on the Company's Condensed Consolidated Balance Sheet as either assets or liabilities measured at fair value (see Note 4 – Fair Value Measurements). The Company has not designated any derivative instruments as hedges for accounting purposes and does not enter into such instruments for speculative trading purposes. If a derivative does not qualify as a hedge or is not designated as a hedge, the changes in fair value are recognized in the other income (expense) section of the Company's Condensed Consolidated Statement of Operations as a net gain or loss on derivative instruments. The Company's cash flow is only impacted when the actual settlements under the derivative contracts result in making a payment to or receiving a payment from the counterparty. These cash settlements represent the cumulative gains and losses on the Company's derivative instruments and do not include a recovery of costs that were paid to acquire or modify the derivative instruments that were settled. Cash settlements are reflected as investing activities in the Company's Condensed Consolidated Statement of Cash Flows.

At June 30, 2016 , the Company had the following outstanding commodity derivative instruments, all of which settle monthly based on the average WTI:

The following table summarizes the location and fair value of all outstanding commodity derivative instruments recorded in the Company's Condensed Consolidated Balance Sheet:

The following table summarizes the location and amounts of gains and losses from the Company's commodity derivative instruments recorded in the Company's Condensed Consolidated Statement of Operations for the periods presented:

In accordance with the FASB's authoritative guidance on disclosures about offsetting assets and liabilities, the Company is required to disclose both gross and net information about instruments and transactions eligible for offset in the statement of financial position as well as instruments and transactions subject to an agreement similar to a master netting agreement. The Company's derivative instruments are presented as assets and liabilities on a net basis by counterparty, as all counterparty contracts provide for net settlement. No margin or collateral balances are deposited with counterparties, and as such, gross amounts are offset to determine the net amounts presented in the Company's Condensed Consolidated Balance Sheet.

The following tables summarize gross and net information about the Company's commodity derivative instruments:

6. Property, Plant and Equipment

The following table sets forth the Company's property, plant and equipment:

 __________________

7. Divestiture

On April 1, 2016, the Company completed the sale of certain legacy wells that have been producing from conventional reservoirs such as the Madison, Red River and other formations in the Williston Basin other than the Bakken or Three Forks formations for cash proceeds of approximately  $12.2 million , which includes, and is subject to further, customary post close adjustments, and a  $4.0 million 10%  secured promissory note due within  one  year. These sold assets primarily consisted of oil and gas properties in the Company's exploration and production segment and included certain other property and equipment in the Company's midstream segment.

For the six months ended June 30, 2016 and the year ended December 31, 2015, the Company recorded impairment charges of $3.6 million and $9.4 million , respectively, which were included in impairment on the Company's Condensed Consolidated Statement of Operations, to adjust the carrying value of these assets to their estimated fair value, determined based on the expected sales price, less costs to sell. There were no similar charges recorded during the three months ended June 30, 2016 and three and six months ended June 30, 2015 . For the three and six months ended June 30, 2016 , customary post close adjustments were included in the loss on sale of properties on the Company's Condensed Consolidated Statement of Operations.

8. Long-Term Debt

The Company's long-term debt consists of the following:

Senior secured revolving line of credit. The Company has a senior secured revolving line of credit (the "Credit Facility") of $2,500.0 million as of June 30, 2016 , which has a maturity date of April 13, 2020. The Credit Facility is restricted to a borrowing base, which is reserve-based and subject to semi-annual redeterminations on April 1 and October 1 of each year. On February 23, 2016, the lenders under the Credit Facility completed their regular semi-annual redetermination of the borrowing base scheduled for April 1, 2016, resulting in a decrease in the borrowing base and aggregate elected commitment from $1,525.0 million to $1,150.0 million .

As of June 30, 2016 , the Company had $35.0 million of LIBOR loans and $14.2 million of outstanding letters of credit issued under the Credit Facility, resulting in an unused borrowing base committed capacity of $1,100.8 million . The weighted average interest rate on borrowings outstanding under the Credit Facility was 2.0% and 1.9% as of June 30, 2016 and December 31, 2015 , respectively. On a quarterly basis, the Company also pays a 0.375% (as of June 30, 2016 ) annualized commitment fee on the average amount of borrowing base capacity not utilized during the quarter and fees calculated on the average amount of letter of credit balances outstanding during the quarter.

The Company was in compliance with the financial covenants of the Credit Facility as of June 30, 2016 .

Senior unsecured notes. At June 30, 2016 , the Company had $2,123.4 million principal amount of senior unsecured notes outstanding with maturities ranging from February 2019 to January 2023 and coupons ranging from 6.5% to 7.25% (the "Notes"). Interest on the Notes is payable semi-annually in arrears. The Notes are guaranteed on a senior unsecured basis by the Company, along with its material subsidiaries (the "Guarantors"), which are 100% owned by the Company. These guarantees are full and unconditional and joint and several among the Guarantors, subject to certain customary release provisions. The indentures governing the Notes contain customary events of default as well as covenants that place restrictions on the Company and certain of its subsidiaries.

Prior to certain dates, the Company has certain options to redeem up to 35% of the Notes at a certain redemption price based on a percentage of the principal amount, plus accrued and unpaid interest to the redemption date, with the proceeds of certain equity offerings so long as the redemption occurs within 180  days of completing such equity offering and at least 65% of the aggregate principal amount of the Notes remains outstanding after such redemption. Prior to certain dates, the Company has the option to redeem some or all of the Notes for cash at certain redemption prices equal to a certain percentage of their principal amount plus an applicable make-whole premium and accrued and unpaid interest to the redemption date. The Company estimates that the fair value of these redemption options is immaterial at June 30, 2016 and December 31, 2015 .

During the six months ended June 30, 2016 , the Company repurchased an aggregate principal amount of $76.6 million of its outstanding Notes, consisting of $1.0 million principal amount of its 7.25% senior unsecured notes due February 2019, $2.3 million principal amount of its 6.5% senior unsecured notes due November 2021, $59.5 million principal amount of its 6.875% senior unsecured notes due March 2022 and $13.8 million principal amount of its 6.875% senior unsecured notes due January 2023, for an aggregate cost of $56.9 million , including accrued interest and fees. For the three and six months ended June 30, 2016 , the Company recognized pre-tax gains of $11.6 million and $18.7 million , respectively, related to these repurchases, which were net of unamortized deferred financing costs write-offs of $0.5 million and $1.0 million , respectively, and are reflected in gain on extinguishment of debt in the Company's Condensed Consolidated Statement of Operations.

Deferred financing costs. At June 30, 2016 , the Company had $36.7 million of deferred financing costs related to the Notes and the Credit Facility. Deferred financing costs of $31.0 million related to the Notes are included in long-term debt on the Company's Condensed Consolidated Balance Sheet at June 30, 2016 , and are being amortized over the respective terms of the Notes. Deferred financing costs of $5.7 million related to the Credit Facility are included in other assets on the Company's Condensed Consolidated Balance Sheet at June 30, 2016 , and are being amortized over the term of the Credit Facility. Amortization of deferred financing costs recorded was $2.0 million and $4.1 million for the three and six months ended June 30, 2016 , respectively, and $1.9 million and $3.5 million for the three and six months ended June 30, 2015 , respectively. These costs are included in interest expense on the Company's Condensed Consolidated Statement of Operations. For the six months ended June 30, 2016 and 2015 , the Company's interest expense also included $1.8 million and $0.5 million charges for unamortized deferred financing costs related to the Credit Facility, which were written off in proportion to the decreases in the borrowing base. No deferred financing costs related to the Credit Facility were written off during the three months ended June 30, 2016 . Aforementioned, the gain on extinguishment of debt in the Company's Condensed Consolidated Statement of Operations included unamortized deferred financing costs write-offs of $0.5 million and $1.0 million related to the repurchased Notes for the three and six months ended June 30, 2016 , respectively. No deferred financing costs related to the Notes were written off during the three and six months ended June 30, 2015 .

9. Asset Retirement Obligations

The following table reflects the changes in the Company's ARO during the six months ended June 30, 2016 :

___________________

At June 30, 2016 , the current portion of the total ARO balance was approximately $0.7 million and was included in accrued liabilities on the Company's Condensed Consolidated Balance Sheet.

10. Income Taxes

The Company's effective tax rate for the three and six months ended June 30, 2016 was 36.9% and 34.2% , respectively. The Company's effective tax rate for the three and six months ended June 30, 2015 was 36.7% and 34.9% , respectively. The effective tax rates for both the six months ended June 30, 2016 and 2015 were lower than the combined federal statutory rate and the statutory rates for the states in which the Company conducts business due to the impact of permanent differences on pre-tax loss for each period. The permanent differences were primarily between amounts expensed for book purposes versus the amounts deductible for income tax purposes related to stock-based compensation vesting during the six months ended June 30, 2016 and 2015 at stock prices lower than the grant date values.

While the Company is in an overall deferred tax liability position, the Company had deferred tax assets for its federal and state tax net operating losses and other tax carryforwards recorded in deferred income taxes at June 30, 2016 . Deferred tax assets are reduced by a valuation allowance when, in the opinion of management, it is more likely than not that some portion or all of the deferred tax assets will not be realized. During the six months ended June 30, 2016 , the Company recorded a valuation allowance of $0.9 million and $0.6 million for Montana net operating losses and for federal charitable contribution carryovers, respectively, based on management's assessment that it is more likely than not that these net deferred tax assets will not be realized prior to their expiration due to their short carryover periods, current economic conditions and expectations for the future. Management determined that a valuation allowance was not required for its U.S. federal tax net operating loss carryforwards as they are expected to be fully utilized before their expiration. However, the amount of deferred tax assets considered realizable could be reduced in the future if subjective positive evidence, such as projections of future growth, become limited by objective negative evidence, such as projected cumulative losses incurred over a three-year period. Management's estimates of future taxable income are significantly affected by changes in commodity prices, the timing and amount of future production and future operating and capital costs.

At June 30, 2016 , the Company did not have any uncertain tax positions requiring adjustments to its tax liability.

11. Common Stock

On February 2, 2016, the Company completed a public offering of 39,100,000 shares of its common stock (including 5,100,000 shares issued pursuant to the underwriters' option to purchase additional common stock) at an offering price of $4.685 per share. Net proceeds from the offering were $183.0 million , after deducting underwriting discounts and commissions and offering expenses, of which $0.4 million is included in common stock and $182.6 million is included in additional paid-in capital on the Company's Condensed Consolidated Balance Sheet at June 30, 2016 . The Company used the net proceeds for general corporate purposes. The offering was made pursuant to an effective shelf registration statement on Form S-3 filed with the SEC on July 15, 2014.

12. Stock-Based Compensation

Restricted stock awards. The Company has granted restricted stock awards to employees and directors under its Amended and Restated 2010 Long Term Incentive Plan, the majority of which vest over a three -year period. The fair value of restricted

stock grants is based on the closing sales price of the Company's common stock on the date of grant. Compensation expense is recognized ratably over the requisite service period. For the six months ended June 30, 2016 , the Company assumed annual forfeiture rates by employee group ranging from 0% to 20.0% based on the Company's forfeiture history for this type of award.

During the six months ended June 30, 2016 , employees and non-employee directors of the Company were granted restricted stock awards equal to 2,573,950 shares of common stock with a $ 4.34 weighted average grant date per share value. Stock-based compensation expense recorded for restricted stock awards for the three and six months ended June 30, 2016 was $4.9 million and $10.7 million , respectively, and $5.1 million and $11.8 million for the three and six months ended June 30, 2015 , respectively. Stock-based compensation expense is included in general and administrative expenses on the Company's Condensed Consolidated Statement of Operations.

Performance share units. The Company has granted performance share units ("PSUs") to officers of the Company under its Amended and Restated 2010 Long Term Incentive Plan. The PSUs are awards of restricted stock units, and each PSU that is earned represents the right to receive one share of the Company's common stock. For the six months ended June 30, 2016 , the Company assumed annual forfeiture rates by employee group ranging from 3.3% to 4.6% based on the Company's forfeiture history for the officer employee groups receiving PSUs.

During the six months ended June 30, 2016 , officers of the Company were granted 910,000 PSUs with a $ 3.00 weighted average grant date per share value. Stock-based compensation expense recorded for PSUs for the three and six months ended June 30, 2016 was $1.3 million and $2.2 million , respectively, and $1.0 million and $1.9 million for the three and six months ended June 30, 2015 , respectively. Stock-based compensation expense is included in general and administrative expenses on the Company's Condensed Consolidated Statement of Operations.

The Company accounted for these PSUs as equity awards pursuant to the FASB's authoritative guidance for share-based payments. The number of PSUs to be earned is subject to a market condition, which is based on a comparison of the total shareholder return ("TSR") achieved with respect to shares of the Company's common stock against the TSR achieved by a defined peer group at the end of the performance periods. Depending on the Company's TSR performance relative to the defined peer group, award recipients will earn between 0% and 200% of the initial PSUs granted. The grant date fair value for each grant of PSUs is recognized on a straight-line basis over a four-year total performance period. All compensation expense related to the PSUs will be recognized if the requisite performance period is fulfilled, even if the market condition is not achieved.

The aggregate grant date fair value of the market-based awards was determined using a Monte Carlo simulation model, which results in an expected percentage of PSUs earned. The Monte Carlo simulation model uses assumptions regarding random projections and must be repeated numerous times to achieve a probabilistic assessment. The key valuation assumptions for the Monte Carlo model are the forecast period, initial value, risk-free interest rate, volatility and correlation coefficients. The risk-free interest rate is the U.S. Treasury bond rate on the date of grant that corresponds to the total performance period. The initial value is the average of the volume weighted average prices for the 30 trading days prior to the start of the performance cycle for the Company and each of its peers. Volatility is the standard deviation of the average percentage change in stock price over a historical period for the Company and each of its peers. The correlation coefficients are measures of the strength of the linear relationship between and amongst the Company and its peers estimated based on historical stock price data.

The following assumptions were used for the Monte Carlo model to determine the grant date fair value and associated stock-based compensation expense of the PSUs granted during the six months ended June 30, 2016 :

For the PSUs granted during the six months ended June 30, 2016 , the Monte Carlo simulation model resulted in approximately 69% of PSUs expected to be earned.

13. Earnings (Loss) Per Share

Basic earnings (loss) per share is computed by dividing the earnings (loss) attributable to common stockholders by the weighted average number of shares outstanding for the periods presented. The calculation of diluted earnings (loss) per share includes the impact of potentially dilutive non-vested restricted shares and PSUs outstanding during the periods presented, unless their effect is anti-dilutive. There are no adjustments made to the earnings (loss) attributable to common stockholders in the calculation of diluted earnings (loss) per share.

The following is a calculation of the basic and diluted weighted average shares outstanding for the three and six months ended June 30, 2016 and 2015 :

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14. Business Segment Information

The Company's exploration and production segment is engaged in the acquisition and development of oil and natural gas properties. Revenues for the exploration and production segment are derived from the sale of oil and natural gas production. The Company's well services business segment (OWS) performs services for the Company's oil and natural gas wells operated by OPNA. Revenues for the well services segment are derived from providing well services, product sales and equipment rentals. The Company's midstream services business segment (OMS) performs salt water gathering and disposal and other midstream services for the Company's oil and natural gas wells operated by OPNA. Revenues for the midstream segment are primarily derived from salt water pipeline transport, salt water disposal and fresh water sales. The revenues and expenses related to work performed by OWS and OMS for OPNA's working interests are eliminated in consolidation, and only the revenues and expenses related to non-affiliated working interest owners are included in the Company's Condensed Consolidated Statement of Operations. These segments represent the Company's three operating units, each offering different products and services. The Company's corporate activities have been allocated to the supported business segments accordingly.

15. Commitments and Contingencies

Included below is a discussion of the Company's various future commitments as of June 30, 2016 . The commitments under these arrangements are not recorded in the accompanying Condensed Consolidated Balance Sheet. The amounts disclosed represent undiscounted cash flows on a gross basis, and no inflation elements have been applied.

Lease obligations. The Company's total rental commitments under leases for office space and other property and equipment as of June 30, 2016 were $22.6 million .

Volume commitment agreements. As of June 30, 2016 , the Company had certain agreements with an aggregate requirement to deliver or transport a minimum quantity of approximately 30.5 MMBbl of crude oil, 23.0 MMBbl of natural gas liquids and 220.6 Bcf of natural gas, prior to any applicable volume credits, within specified timeframes, all of which are ten years or less. The future commitments under certain agreements cannot be estimated as they are based on fixed differentials relative to WTI under the agreements as compared to the differential relative to WTI for the Williston Basin for the production month. The estimable future commitments under these agreements were approximately $442.0 million as of June 30, 2016 .

Purchase agreements . As of  June 30, 2016 , the Company had certain agreements for the purchase of fresh water with an aggregate future commitment of approximately $38.8 million .

Litigation. The Company is party to various legal and/or regulatory proceedings from time to time arising in the ordinary course of business. While the ultimate outcome and impact to the Company cannot be predicted with certainty, the Company believes that all such matters are without merit and involve amounts which, if resolved unfavorably, either individually or in the aggregate, will not have a material adverse effect on its financial condition, results of operations or cash flows. When the Company determines that a loss is probable of occurring and is reasonably estimable, the Company accrues an undiscounted liability for such contingencies based on its best estimate using information available at the time. The Company discloses contingencies where an adverse outcome may be material, or in the judgment of management, the matter should otherwise be disclosed.

16. Condensed Consolidating Financial Information

The Notes (see Note 8 – Long-Term Debt) are guaranteed on a senior unsecured basis by the Guarantors, which are 100% owned by the Company. These guarantees are full and unconditional and joint and several among the Guarantors. Certain of the Company's immaterial wholly-owned subsidiaries do not guarantee the Notes ("Non-Guarantor Subsidiaries").

The following financial information reflects consolidating financial information of the parent company, Oasis Petroleum Inc. ("Issuer"), and its Guarantors on a combined basis, prepared on the equity basis of accounting. The Non-Guarantor Subsidiaries are immaterial and, therefore, not presented separately. The information is presented in accordance with the requirements of Rule 3-10 under the SEC's Regulation S-X. The financial information may not necessarily be indicative of results of operations, cash flows or financial position had the Guarantors operated as independent entities. The Company has not presented separate financial and narrative information for each of the Guarantors because it believes such financial and narrative information would not provide any additional information that would be material in evaluating the sufficiency of the Guarantors.

Condensed Consolidating Balance Sheet