Form 424B5

Our common stock is listed on the New York Stock Exchange under the symbol “OAS.” On December 2, 2013, the last reported trading price of our common stock as reported on the New York Stock Exchange was $45.88 per share.

Investing in our common stock involves risk. See “Risk Factors” beginning on page S-4 of this prospectus supplement.

The underwriter has agreed to purchase the common stock at a purchase price of $44.94 per share, resulting in $314,580,000 aggregate gross proceeds to us. The underwriter may offer the shares of common stock from time to time in one or more transactions in the over-the-counter market or through negotiated transactions at market prices or at negotiated prices.

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or determined if this prospectus supplement or the accompanying prospectus is truthful or complete. Any representation to the contrary is a criminal offense.

This document is in two parts. The first part is the prospectus supplement and the documents incorporated by reference herein, which describes the specific terms of this offering of our common stock. The second part is the accompanying prospectus, which gives more general information, some of which may not apply to our common stock or this offering. If the information relating to the offering varies between the prospectus supplement and the accompanying prospectus, you should rely on the information in this prospectus supplement.

You should rely only on the information contained in or incorporated by reference into this prospectus supplement, the accompanying prospectus and any related free writing prospectus. We have not, and the underwriters have not, authorized any dealer, salesman or other person to provide you with additional or different information. If anyone provides you with different or inconsistent information, you should not rely on it. This prospectus supplement and the accompanying prospectus are not an offer to sell or the solicitation of an offer to buy any securities other than the securities to which they relate and are not an offer to sell or the solicitation of an offer to buy securities in any jurisdiction to any person to whom it is unlawful to make an offer or solicitation in that jurisdiction. You should not assume that the information contained in this prospectus supplement is accurate as of any date other than the date on the front cover of this prospectus supplement, or that the information contained in any document incorporated by reference is accurate as of any date other than the date of the document incorporated by reference, regardless of the time of delivery of this prospectus supplement or any sale of a security.

Unless otherwise indicated or the context otherwise requires, all references in this prospectus supplement to “we,” “us,” “our,” “Oasis Petroleum” and the “Company” refer to Oasis Petroleum Inc. and its subsidiaries and the term “Oasis” refers to Oasis Petroleum Inc.

We file annual, quarterly and current reports and other information with the Securities and Exchange Commission (the “SEC”) (File No. 001- 34776) pursuant to the Securities Exchange Act of 1934 (the “Exchange Act”). You may read and copy any documents that are filed at the SEC’s public reference room at 100 F Street, N.E., Washington, D.C. 20549. You may also obtain copies of these documents at prescribed rates from the public reference section of the SEC at its Washington address. Please call the SEC at 1-800-SEC-0330 for further information.

Our filings are also available to the public through the SEC’s website at www.sec.gov.

The SEC allows us to “incorporate by reference” information that we file with them, which means that we can disclose important information to you by referring you to documents previously filed with the SEC. The information incorporated by reference is an important part of this prospectus supplement, and the information that we later file with the SEC will automatically update and supersede this information. The following documents we filed with the SEC pursuant to the Exchange Act are incorporated herein by reference:

These reports contain important information about us, our financial condition and our results of operations.

All future documents filed pursuant to Sections 13(a), 13(c), 14 and 15(d) of the Exchange Act (excluding any information furnished pursuant to Item 2.02 or Item 7.01 on any Current Report on Form 8-K) before the termination of the offering of securities under this prospectus supplement shall be deemed to be incorporated in this prospectus supplement by reference and to be a part hereof from the date of filing of such documents. Any statement contained herein, or in a document incorporated or deemed to be incorporated by reference herein, shall be deemed to be modified or superseded for purposes of this prospectus supplement to the extent that a statement contained herein or in any subsequently filed document that also is or is deemed to be incorporated by reference herein, modifies or supersedes such statement. Any such statement so modified or superseded shall not be deemed, except as so modified or superseded, to constitute a part of this prospectus supplement.

You may request a copy of these filings at no cost by writing or telephoning us at the following address and telephone number:

We also maintain a website at http://www.oasispetroleum.com. However, the information on our website is not part of this prospectus supplement or the accompanying prospectus.

Various statements contained in or incorporated by reference into this prospectus supplement that express a belief, expectation, or intention, or that are not statements of historical fact, are forward-looking statements within the meaning of Section 27A of the Securities Act of 1933 (the “Securities Act”) and Section 21E of the Exchange Act. These forward-looking statements include statements, projections and estimates concerning our operations, performance, business strategy, oil and natural gas reserves, drilling program, capital expenditures, liquidity and capital resources, the timing and success of specific projects, outcomes and effects of litigation, claims and disputes, derivative activities and potential financing. Forward-looking statements are generally accompanied by words such as “estimate,” “project,” “predict,” “believe,” “expect,” “anticipate,” “potential,” “could,” “may,” “foresee,” “plan,” “goal” or other words that convey the uncertainty of future events or outcomes. Forward-looking statements are not guarantees of performance. We have based these forward-looking statements on our current expectations and assumptions about future events. These statements are based on certain assumptions and analyses made by us in light of our experience and our perception of historical trends, current conditions and expected future developments as well as other factors we believe are appropriate under the circumstances. Actual results may differ materially from those implied or expressed by the forward-looking statements. These forward-looking statements speak only as of the date of this prospectus supplement, or if earlier, as of the date they were made. We disclaim any obligation to update or revise these statements unless required by law, and we caution you not to rely on them unduly. While our management considers these expectations and assumptions to be reasonable, they are inherently subject to significant business, economic,

competitive, regulatory and other risks, contingencies and uncertainties relating to, among other matters, the risks discussed in “Risk Factors” in our Annual Report on Form 10-K for the year ended December 31, 2012, in the other documents incorporated by reference herein and in our subsequent SEC filings, as well as those factors summarized below:

Reserve engineering is a process of estimating underground accumulations of oil and natural gas that cannot be measured in an exact way. The accuracy of any reserve estimate depends on the quality of available data, the interpretation of such data and price and cost assumptions made by our reserve engineers. In addition, the results of drilling, testing and production activities may justify revisions of estimates that were made previously. If significant, such revisions would change the schedule of any further production and development drilling. Accordingly, reserve estimates may differ from the quantities of oil and natural gas that are ultimately recovered.

SUMMARY

This summary provides a brief overview of information contained elsewhere in this prospectus supplement, the accompanying prospectus and the documents we incorporate by reference. Because it is abbreviated, this summary does not contain all of the information that you should consider before investing in our common stock in this offering. You should read the entire prospectus supplement, the accompanying prospectus, the documents incorporated by reference and the other documents to which we refer for a more complete understanding of our business and this offering. Please read the section entitled “Risk Factors” beginning on page S-4 of this prospectus supplement and beginning on page 5 of the accompanying prospectus, and additional information contained in our Annual Report on Form 10-K for the year ended December 31, 2012 and our Quarterly Reports on Form 10-Q for the quarterly periods ended March 31, 2013, June 30, 2013 and September 30, 2013, each of which is incorporated by reference in this prospectus supplement for more information about important factors you should consider before investing in our common stock in this offering.

Overview

We are an independent exploration and production company focused on the acquisition and development of unconventional oil and natural gas resources in the Montana and North Dakota regions of the Williston Basin. As of September 30, 2013, we have accumulated approximately 356,000 net leasehold acres in the Williston Basin. We are currently exploiting significant resource potential from the Bakken and Three Forks formations, which are present across a substantial portion of our acreage. We believe the location, size and concentration of our acreage in our primary project areas create an opportunity for us to achieve cost, recovery and production efficiencies through the large-scale development of our project inventory. Our management team has a proven track record in identifying, acquiring and executing large, repeatable development drilling programs, which we refer to as “resource conversion” opportunities, and has substantial Williston Basin experience. During the nine months ended September 30, 2013, we completed and placed on production 89 gross operated wells in the Williston Basin. We have built our Williston Basin leasehold acreage position primarily through acquisitions in our three primary project areas: West Williston, East Nesson and Sanish.

Recent Developments

Williston Acquisitions

On October 1, 2013, we completed the acquisition of approximately 136,000 net acres in and around our existing position in West Williston, which is in the Williston Basin for $1,478.6 million, which is subject to further customary post close adjustments (the “West Williston Acquisition”). The effective date for the transaction was April 1, 2013.

We believe, based on estimates prepared by our independent reserve engineers, that the West Williston Acquisition substantially increases our reserves portfolio by immediately adding approximately 43.9 MMBoe of proved reserves of which 40% are developed. The West Williston Acquisition also adds approximately 136,000 net acres, of which 91,000 net acres are prospective for all depths including the Bakken and Three Forks reservoirs. The acreage is generally in large contiguous blocks and is 97% held-by-production. Additionally, the added acreage consists of 99 operated spacing units and 82 nonoperated spacing units. We expect to operate approximately 91% of the acreage, and the operated acreage has an average working interest of 67%.

In addition, on September 26, 2013, we completed three acquisitions of assets in East Nesson totaling approximately 25,000 net acres, in the aggregate, for cash consideration of $54.8 million, which is subject to further customary post close adjustments (the “East Nesson Acquisitions”). The net acreage acquired in the East Nesson Acquisitions is included in the approximately 356,000 net acres we had accumulated as of September 30, 2013. As part of the East Nesson Acquisitions, the Company also agreed to invest, expend and/or incur expenses

of $8.2 million in connection with drilling and completion activities for certain wells. The effective dates for the East Nesson Acquisitions were all July 1, 2013.

We funded the purchase price of the West Williston Acquisition and the East Nesson Acquisitions with proceeds from our 144A Notes Offering (as defined below) and borrowings under our revolving credit facility.

Private Placement of Senior Notes

On September 24, 2013, we completed a private placement of $1.0 billion in aggregate principal amount of our 6.875% Senior Notes due 2022 (the “144A Notes Offering”). We received aggregate net proceeds of approximately $983.0 million, which we used to fund a portion of the purchase price of the West Williston Acquisition.

Redetermination of Borrowing Base

On September 3, 2013, we amended our revolving credit facility with our bank syndicate, and the lenders under our revolving credit facility completed their regular semi-annual redetermination of the borrowing base (the “September 2013 Redetermination”), based on our mid-year reserves. Following the September 2013 Redetermination, our borrowing base increased from $1,250.0 million to $1,500.0 million and elected commitments also totaled $1,500.0 million. As of September 30, 2013, after giving effect on a pro forma basis to the West Williston Acquisition, we had $605.2 million of outstanding indebtedness under our revolving credit facility, including approximately $5.2 million of outstanding letters of credit, out of an aggregate secured borrowing capacity under our revolving credit facility of $1,500.0 million. After the closing of the 144A Notes Offering and the West Williston Acquisition, the lenders kept the borrowing base at $1,500.0 million.

Corporate Information

Our principal executive offices are located at 1001 Fannin Street, Suite 1500, Houston, Texas 77002, and our telephone number at that address is (281) 404-9500. Our website is located at http://www.oasispetroleum.com. However, the information on our website is not part of this prospectus supplement, and you should rely only on the information contained in this prospectus supplement, the accompanying prospectus, any related free writing prospectus and in the documents incorporated herein by reference when making a decision as to whether to buy our common stock in this offering.

THE OFFERING


Issuer		Oasis Petroleum Inc.
Shares of common stock offered		7,000,000 shares.
Shares of common stock outstanding following this offering¹		100,699,249 shares.
Use of proceeds		We will use the estimated net proceeds from this offering of approximately $314.4 million to repay outstanding borrowings under our revolving credit facility and for general corporate purposes. For more information about our use of proceeds from this offering, see “Use of Proceeds.”
Conflicts of interest		We intend to use a portion of the net proceeds of this offering to repay indebtedness owed by us under our credit facility. See “Use of Proceeds.” Because a repayment of the outstanding borrowings under our credit facility could result in at least 5% of the net proceeds of this offering being paid to an affiliate of the underwriter who is a lender under our revolving credit facility, this offering is being made in compliance with the requirements of Rule 5121 of the Financial Industry Regulatory Authority, or FINRA. In accordance with that rule, no “qualified independent underwriter” is required, because a bona fide public market exists in the shares, as that term is defined in the rule. For more information, see “Underwriting (Conflicts of Interest)—Conflicts of Interest.”

(1)	Based on 93,699,249 shares outstanding as of November 29, 2013.

Unless we indicate otherwise or the context otherwise requires, all of the information in this prospectus supplement does not reflect 5.1 million shares available for issuance under our 2010 Long-Term Incentive Plan.

RISK FACTORS

Investing in our common stock involves substantial risk. You should carefully consider the risk factors set forth or cross-referenced in the sections entitled “Risk Factors” beginning on page S-4 of this prospectus supplement and beginning on page 5 of the accompanying prospectus, and the other information contained in this prospectus supplement and the accompanying prospectus and the documents incorporated by reference therein, prior to making an investment in our common stock.

An investment in our common stock involves risk. In addition to the risks described below, you should also carefully read the risk factors included in the section entitled “Risk Factors” in our Annual Report on Form 10-K for the year ended December 31, 2012 and in our Quarterly Report on Form 10-Q for the quarterly period ended September 30, 2013, together with all of the other information included in this prospectus supplement, the accompanying prospectus and the documents we have incorporated by reference into this prospectus supplement in evaluating an investment in our common stock. If any of the described risks actually were to occur, our business, financial condition or results of operations could be affected materially and adversely. In that case, the trading price of our common stock could decline and you could lose all or part of your investment.

The market price of our common stock has fluctuated substantially in the past and is likely to fluctuate in the future as a result of a number of factors.

The market price of our common stock and the number of shares traded each day have varied greatly. For example, during the period beginning on January 1, 2013 and ending on December 2, 2013, the closing market price of our common stock ranged between $32.51 and $56.72. Such fluctuations may continue because of numerous factors, including:

In addition, in recent years the stock market has experienced extreme price and volume fluctuations. This volatility has had a significant effect on the market prices of securities issued by many companies for reasons unrelated to their operating performance. These broad market fluctuations may materially and adversely affect our stock price, regardless of our operating results.

Our amended and restated certificate of incorporation and amended and restated bylaws, as well as Delaware law, contain provisions that could discourage acquisition bids or merger proposals, which may adversely affect the market price of our common stock.

Our amended and restated certificate of incorporation authorizes our Board of Directors to issue preferred stock without stockholder approval. If our Board of Directors elects to issue preferred stock, it could be more difficult for a third party to acquire us. In addition, some provisions of our amended and restated certificate of incorporation and amended and restated bylaws could make it more difficult for a third party to acquire control of us, even if the change of control would be beneficial to our stockholders, including:

Delaware law prohibits us from engaging in any business combination with any “interested stockholder,” meaning generally that a stockholder who beneficially owns more than 15% of our stock cannot acquire us for a period of three years from the date this person became an interested stockholder, unless various conditions are met, such as approval of the transaction by our Board of Directors.

In order to raise additional capital, effect acquisitions, or for other purposes, we may in the future offer additional shares of our common stock or other securities convertible into, or exchangeable for, our common stock at prices that may not be the same as the price per share of this offering. We have an effective shelf registration statement from which additional shares of common stock and other securities can be offered. We cannot assure you that we will be able to sell shares or other securities in any other offering at a price per share that is equal to or greater than the price per share paid by investors in this offering. If the price per share at which we sell additional shares of our common stock or related securities in future transactions is less than the price per share in this offering, investors who purchase our common stock in this offering will suffer a dilution of their investment. In addition, equity awards under our equity compensation plan may cause further dilution.

Sales of a substantial amount of our common stock in the public market, or the perception that these sales may occur, could reduce the market price of our common stock. This could also impair our ability to raise additional capital through the sale of our securities.

We do not intend to pay, and we are currently prohibited from paying, dividends on our common stock and, consequently, our shareholders’ only opportunity to achieve a return on their investment is if the price of our stock appreciates.

We do not plan to declare dividends on shares of our common stock in the foreseeable future. Additionally, we are currently prohibited from making any cash dividends pursuant to the terms of our revolving credit facility and the indentures governing our senior unsecured notes. Consequently, our shareholders’ only opportunity to achieve a return on their investment in us will be if the market price of our common stock appreciates, which may not occur, and the shareholder sells their shares at a profit. There is no guarantee that the price of our common stock will ever exceed the price that the shareholder paid.

We expect the net proceeds from this offering to be approximately $314.4 million, after deducting estimated fees and expenses (including underwriting discounts and commissions). We intend to use the net proceeds from this offering to repay outstanding borrowings under our revolving credit facility and for general corporate purposes.

As of September 30, 2013, after giving effect on a pro forma basis to the West Williston Acquisition, we had $600.0 million of outstanding borrowings under our revolving credit facility, which bore interest at a rate of approximately 2.0%, and had $5.2 million of outstanding letters of credit under our revolving credit facility. Borrowings under the credit facility are incurred for general corporate purposes, including the funding of our capital budget and to consummate the West Williston Acquisition and the East Nesson Acquisitions. Any amounts repaid with the proceeds from this offering may be reborrowed in the future. A repayment of the outstanding borrowings under our credit facility could result in at least 5% of the net proceeds of this offering being paid to an affiliate of the underwriter who is a lender under our revolving credit facility. Accordingly, this offering is being made in compliance with the requirements of Rule 5121 of the Financial Industry Regulatory Authority. For more information, see “Underwriting (Conflicts of Interest)—Conflicts of Interest.”

The following table sets forth our unaudited capitalization at September 30, 2013:

Our common stock is listed on the New York Stock Exchange under the symbol “OAS.” The following table shows, for the periods indicated, the high and low reported sale prices for our common stock, as reported on the New York Stock Exchange.

On December 2, 2013, the last sales price of our common stock as reported on the New York Stock Exchange was $45.88 per share.

The number of shareholders of record of our common stock was approximately 39,737 as of November 18, 2013.

We have not paid, and do not intend to pay in the foreseeable future, cash dividends on our common stock. Covenants contained in our credit facility and the indentures governing our senior notes restrict the payment of dividends on our common stock. We currently intend to retain all future earnings to fund the development and growth of our business. Any payment of future dividends will be at the discretion of our board of directors and will depend on, among other things, our earnings, financial condition, capital requirements, level of indebtedness, statutory and contractual restrictions applying to the payment of dividends and other considerations that our Board of Directors deems relevant.

The following discussion summarizes the material U.S. federal income tax consequences to Non-U.S. holders (as defined below) with respect to the acquisition, ownership and disposition of our common stock. This discussion is based on current provisions of the Internal Revenue Code of 1986, as amended (the “Code”), applicable U.S. Treasury Regulations, judicial opinions, published positions of the Internal Revenue Service (the “IRS”) and administrative and judicial authorities, all of which are subject to change, possibly with retroactive effect, or are subject to different interpretations. We have not sought any ruling from the IRS with respect to the statements made and the conclusions reached in this discussion and there can be no assurance that the IRS will agree with such statements or conclusions.

This discussion assumes that a Non-U.S. holder holds our common stock as a capital asset (generally, property held for investment). This discussion does not address all aspects of U.S. federal income taxation or any U.S. federal tax laws other than U.S. federal income tax laws (e.g., estate or gift tax laws) and does not address the 3.8% Medicare tax on unearned income or any aspects of state, local, or non-U.S. taxation. In addition, this discussion does not address all tax considerations that may be important to a particular holder in light of the holder’s circumstances, or to certain categories of investors that may be subject to special treatment under the U.S. federal income tax laws, including, without limitation:

If an entity treated as a partnership for U.S. federal income tax purposes holds our common stock, the tax treatment of a partner of the partnership generally will depend upon the status of the partner and the activities of the partnership. Accordingly, we urge partnerships that hold our common stock and partners in such partnerships to consult their tax advisors.

INVESTORS CONSIDERING THE PURCHASE OF OUR COMMON STOCK ARE ENCOURAGED TO CONSULT THEIR TAX ADVISORS WITH RESPECT TO THE APPLICATION OF U.S. FEDERAL INCOME TAX LAWS TO THEIR PARTICULAR SITUATIONS AS WELL AS ANY TAX CONSEQUENCES ARISING UNDER U.S. ESTATE AND GIFT TAX LAWS OR UNDER THE LAWS OF ANY STATE, LOCAL OR FOREIGN TAXING JURISDICTION, OR UNDER ANY APPLICABLE TAX TREATY.

A “Non-U.S. holder” for purposes of this discussion is any beneficial owner of our common stock that acquires such stock for cash pursuant to the terms of this prospectus supplement and that is not, for U.S. federal income tax purposes:

We do not intend to make any distributions on our common stock in the foreseeable future. However, in the event we do make distributions, such distributions will be treated as dividends to the extent of our current and accumulated earnings and profits as determined under U.S. federal income tax principles and will be subject to withholding as discussed below. Any portion of a distribution that exceeds our current and accumulated earnings and profits will first be applied to reduce the Non-U.S. holder’s basis in the common stock and, to the extent such portion exceeds the Non-U.S. holder’s basis, the excess will be treated as gain from the disposition of the common stock, the tax treatment of which is discussed below under “— Gain on Sale or Other Disposition of Common Stock.”

Dividends paid to a Non-U.S. holder on our common stock will generally be subject to U.S. withholding tax at a rate of 30% or such lower rate as may be specified by an applicable income tax treaty. A Non-U.S. holder of our common stock that wishes to receive the benefits of a reduced treaty rate for dividends must (i) provide the withholding agent with an IRS Form W-8BEN (or other applicable form) certifying qualification for the reduced rate, or (ii) if our common stock is held through certain foreign intermediaries, satisfy the relevant certification requirements of applicable U.S. Treasury Regulations.

Dividends that are effectively connected with the conduct of a trade or business conducted by the Non-U.S. holder within the United States (and, where an income tax treaty so requires, are attributable to a permanent establishment maintained by the Non-U.S. holder in the United States) are subject to U.S. federal income tax on a net income basis in the same manner as if the Non-U.S. holder were a United States person, as defined under the Code, unless an applicable income tax treaty provides otherwise. Effectively connected dividend income will not be subject to U.S. withholding tax if the Non-U.S. holder satisfies certain certification requirements by providing to the withholding agent a properly executed IRS Form W-8ECI (or successor form) certifying eligibility for the exemption. Effectively connected dividends received by a foreign corporation may be subject to an additional “branch profits tax” at a 30% rate or such lower rate as may be specified by an applicable income tax treaty.

In general, a Non-U.S. holder will not be subject to U.S. federal income tax on any gain realized upon the sale, exchange, redemption, retirement or other taxable disposition of the Non-U.S. holder’s shares of common stock unless:

A Non-U.S. holder described in the first bullet point above will be subject to tax on the net gain realized from the sale or other disposition under regular graduated U.S. federal income tax rates in the same manner as if it were a United States person (as defined in the Code), and if the Non-U.S. holder is a corporation, it may also be subject to the branch profits tax at a rate of 30% of its effectively connected earnings and profits or at such lower rate as may be specified by an applicable income tax treaty.

An individual Non-U.S. holder described in the second bullet point above will be subject to a flat 30% tax on the gain derived from the sale or other disposition, which may be offset by U.S. source capital losses.

Generally, a corporation is a USRPHC if the fair market value of its U.S. real property interests equals or exceeds 50% of the sum of the fair market value of its worldwide real property interests and its other assets used or held for use in a trade or business. Because of the oil and natural gas properties and other real property assets we own, we believe that we are and will remain a USRPHC. However, so long as our common stock continues to be treated as regularly traded on an established securities market, a Non-U.S. holder will be taxable on gain recognized on the disposition of our common stock as a result of our status as a USRPHC only if the Non-U.S. holder actually or constructively owns or has owned at any time during the shorter of the five-year period preceding the date of disposition or the holder’s holding period more than 5% of our common stock. If our common stock were not considered to be regularly traded on an established securities market, all Non-U.S. holders would be subject to U.S. federal income tax (and withholding in respect thereof) on a disposition of our common stock.

Non-U.S. holders are urged to consult their tax advisors with respect to the application of the foregoing rules to their ownership and disposition of our common stock.

We must report annually to the IRS and to a Non-U.S. holder the amount of dividends paid to such holder, the holder’s name and address, and any tax withheld with respect to those dividends, regardless of whether withholding is required. Copies of the information returns reporting such dividends and withholding may also be made available to the tax authorities in the country in which the Non-U.S. holder resides or is established under the provisions of an applicable income tax treaty.

U.S. backup withholding will be imposed on certain payments to persons that fail to furnish the information required under the U.S. information reporting requirements. A Non-U.S. holder will be exempt from this backup withholding if such holder properly provides an IRS Form W-8BEN (or valid substitute or successor form)

certifying that it is not a United States person (as defined in the Code) or otherwise establishes an exemption, provided that the withholding agent does not have actual knowledge, or reason to know, that the beneficial owner is a United States person that is not an exempt recipient.

The gross proceeds from the sale or other disposition of our common stock may be subject to information reporting and backup withholding. If a Non-U.S. holder sells or disposes of our common stock outside the United States through a non-U.S. office of a non-U.S. broker and the sales proceeds are paid to the Non-U.S. holder outside the United States, then the U.S. backup withholding and information reporting requirements generally will not apply to that payment. However, unless such a broker has documentary evidence in its records that the Non-U.S. holder is not a United States person and certain other conditions are met, or the Non-U.S. holder otherwise establishes an exemption, information reporting will apply to a payment of the proceeds of the disposition of our common stock effected outside the United States by such a broker if it has certain connections to the United States.

Backup withholding is not an additional tax. Any amount withheld under the backup withholding rules is allowable as a credit against the Non-U.S. holder’s U.S. federal income tax liability, if any. If withholding results in an overpayment of taxes, a refund may be obtained, provided that certain required information is timely provided to the IRS.

Sections 1471 through 1474 of the Code, and the U.S. Treasury Regulations and administrative guidance promulgated thereunder (“FATCA”) impose a 30% withholding tax on any dividends on our common stock and on the gross proceeds from a disposition of our common stock in each case if paid to a foreign financial institution or a non-financial foreign entity (including, in some cases, when such foreign financial institution or entity is acting as an intermediary), unless (i) in the case of a foreign financial institution, such institution enters into an agreement with the U.S. government to withhold on certain payments, and to collect and provide to the U.S. tax authorities substantial information regarding U.S. account holders of such institution (which includes certain equity and debt holders of such institution, as well as certain account holders that are foreign entities with U.S. owners), (ii) in the case of a non-financial foreign entity, such entity certifies that it does not have any “substantial U.S. owners” (as defined in the Code) or provides the withholding agent with a certification identifying the direct and indirect substantial U.S. owners of the entity, or (iii) the foreign financial institution or non-financial foreign entity otherwise qualifies for an exemption from these rules. Certain countries have entered into, and other countries are expected to enter into, agreements with the United States to facilitate the type of information reporting required under FATCA, which will reduce but not eliminate the risk of FATCA withholding for investors in or holding our common stock through financial institutions in such countries.

This withholding obligation under FATCA with respect to dividends paid on our common stock will not begin until July 1, 2014, and with respect to the gross proceeds from dispositions of our common stock, will not begin until January 1, 2017. Neither we nor any other person would be required to pay additional amounts to a Non-U.S. holder as a result of FATCA withholding. Non-U.S. holders are urged to consult their own tax advisors with respect to the U.S. federal income tax consequences of FATCA to their ownership and disposition of our common stock.

EACH PROSPECTIVE INVESTOR SHOULD CONSULT ITS OWN TAX ADVISOR REGARDING THE PARTICULAR U.S. FEDERAL, STATE, LOCAL AND NON-U.S. TAX CONSEQUENCES OF THE ACQUISITION, OWNERSHIP AND DISPOSITION OF OUR COMMON STOCK, INCLUDING THE CONSEQUENCES OF ANY PROPOSED CHANGE IN APPLICABLE LAWS.

Citigroup Global Markets Inc. is acting as sole underwriter of the offering. Subject to the terms and conditions set forth in an underwriting agreement between us and the underwriter, we have agreed to sell to the underwriter, and the underwriter has agreed to purchase from us 7,000,000 shares of our common stock.

The underwriter has agreed to purchase all of the shares sold under the underwriting agreement if any of these shares are purchased, subject to the terms and conditions set forth in the underwriting agreement,

We have agreed to indemnify the underwriter against certain liabilities, including liabilities under the Securities Act of 1933, as amended, or to contribute to payments the underwriter may be required to make in respect of those liabilities.

The underwriter is offering the shares, subject to prior sale, when, as and if issued to and accepted by them, subject to approval of legal matters by their counsel, including the validity of the shares, and other conditions contained in the underwriting agreement, such as the receipt by the underwriter of officer’s certificates and legal opinions. The underwriter reserves the right to withdraw, cancel or modify offers to the public and to reject orders in whole or in part.

The underwriter is purchasing the shares of common stock from us at $44.94 per share (representing approximately $314,580,000 aggregate gross proceeds to us, before we deduct our out-of-pocket expenses of approximately $150,000. The underwriter may offer the shares of common stock from time to time for sale in one or more transactions on the New York Stock Exchange, in the over-the-counter market, through negotiated transactions or otherwise at market prices prevailing at the time of sale, at prices related to prevailing market prices or at negotiated prices. In connection with the sale of the shares of common stock offered hereby, the underwriter may be deemed to have received compensation in the form of underwriting discounts. The underwriter may effect such transactions by selling shares of common stock to or through dealers, and such dealers may receive compensation in the form of discounts, concessions or commissions from the underwriter and / or purchasers of shares of common stock for whom they may act as agents or to whom they may sell as principal.

We and all of our directors and officers have agreed that, without the prior written consent of the underwriter and subject to certain exceptions, on behalf of the underwriter, we and they will not, during the period ending 90 days after the date of the underwriting agreement:

The restrictions described in the immediately preceding paragraph shall not apply to, among other things:

The shares are listed on the New York Stock Exchange under the symbol “OAS”.

In connection with the offering, the underwriter may purchase and sell our common stock in the open market. These transactions may include short sales, purchases on the open market to cover positions created by short sales and stabilizing transactions. Short sales involve the sale by the underwriter of a greater number of shares than they are required to purchase in the offering. A short position is more likely to be created if the underwriter is concerned that there may be downward pressure on the price of our common stock in the open market after pricing that could adversely affect investors who purchase in the offering. Stabilizing transactions consist of various bids for or purchases of shares of common stock made by the underwriter in the open market prior to the completion of the offering.

Similar to other purchase transactions, the underwriter’s purchases to cover the short sales may have the effect of raising or maintaining the market price of our common stock or preventing or retarding a decline in the market price of our common stock. As a result, the price of our common stock may be higher than the price that might otherwise exist in the open market. The underwriter may conduct these transactions on the New York Stock Exchange, in the over-the-counter market or otherwise.

Neither we nor the underwriter makes any representation or prediction as to the direction or magnitude of any effect that the transactions described above may have on the price of our common stock. In addition, neither we nor the underwriter make any representation that the underwriter will engage in these transactions or that these transactions, once commenced, will not be discontinued without notice.

In connection with the offering, the underwriter may distribute prospectuses by electronic means, such as e-mail. In addition, the underwriter may facilitate Internet distribution for this offering to certain of its Internet subscription customers. The underwriter may allocate a limited number of shares for sale to its online brokerage customers. An electronic prospectus supplement and accompanying prospectus may be available on the Internet website maintained by the underwriter. Other than the prospectus supplement and accompanying prospectus in electronic format, the information on the underwriter’s website is not part of this prospectus supplement or the registration statement of which this prospectus supplement and accompanying prospectus are a part, has not been approved and/or endorsed by us or the underwriter or any selling group member in its capacity as underwriter or selling group member and should not be relied upon by investors.

The underwriter and certain of its affiliates are full service financial institutions engaged in various activities, which may include securities trading, commercial and investment banking, financial advisory, investment management, investment research, principal investment, hedging, financing and brokerage activities. The underwriter and its affiliates have, from time to time, performed, and may in the future perform, various financial advisory, commercial banking and investment banking services for us and our affiliates, for which they received or will receive customary fees, commissions and expenses. For example, an affiliate of the underwriter is a lender under our revolving credit facility and, accordingly, may receive a portion of the net proceeds from this offering.

In the ordinary course of their various business activities, the underwriter and its affiliates may make or hold a broad array of investments and actively trade debt and equity securities (or related derivative securities) and financial instruments (including bank loans) for their own account and for the accounts of their customers and may at any time hold long and short positions in such securities and instruments. Such investment and securities activities may involve securities and instruments of the issuer or its affiliates. The underwriter and its affiliates may also make investment recommendations and/or publish or express independent research views in respect of such securities or instruments and may at any time hold, or recommend to clients that they acquire, long and/or short positions in such securities and instruments.

We intend to use a portion of the net proceeds of this offering to repay indebtedness owed by us under our revolving credit facility. As a result, an affiliate of Citigroup Global Markets Inc., could receive at least 5% of the net proceeds of this offering, and, in that case, such underwriter would be deemed to have a conflict of interest under FINRA Rule 5121 (Public Offerings of Securities with Conflicts of Interest). In the event of any such conflict of interest, the offering would be subject to the applicable provisions of FINRA Rule 5121. In accordance with that rule, no “qualified independent underwriter” is required for this offering, because a bona fide public market exists in the shares, as that term is defined in the rule. In addition, in accordance with FINRA Rule 5121, such underwriter would not be permitted to confirm a sale to an account over which it exercises discretionary authority without first receiving specific written approval from the account holder.

In relation to each Member State of the European Economic Area which has implemented the Prospectus Directive (each, a “Relevant Member State”), with effect from and including the date on which the Prospectus Directive is implemented in that Relevant Member State (the “Relevant Implementation Date”) no offer of shares may be made to the public in that Relevant Member State other than:

This prospectus supplement and the accompanying prospectus have been prepared on the basis that any offer of shares in any Relevant Member State will be made pursuant to an exemption under the Prospectus Directive from the requirement to publish a prospectus for offers of shares. Accordingly, any person making or intending to make an offer in that Relevant Member State of shares which are the subject of the offering contemplated in this prospectus supplement and the accompanying prospectus may only do so in circumstances in which no obligation arises for us or the underwriter to publish a prospectus pursuant to Article 3 of the Prospectus Directive in relation to such offer. Neither we nor the underwriter has authorized, nor do we or the underwriter authorize, the making of any offer of shares in circumstances in which an obligation arises for us or the underwriter to publish a prospectus for such offer.

For the purpose of the above provisions, the expression “an offer to the public” in relation to any shares in any Relevant Member State means the communication in any form and by any means of sufficient information on the terms of the offer and the shares to be offered so as to enable an investor to decide to purchase or subscribe the shares, as the same may be varied in the Relevant Member State by any measure implementing the Prospectus Directive in the Relevant Member State and the expression “Prospectus Directive” means Directive 2003/71/EC (including the 2010 PD Amending Directive, to the extent implemented in the Relevant Member States) and includes any relevant implementing measure in the Relevant Member State and the expression “2010 PD Amending Directive” means Directive 2010/73/EU.

In addition, in the United Kingdom, this document is being distributed only to, and is directed only at, and any offer subsequently made may only be directed at persons who are “qualified investors” (as defined in the Prospectus Directive) (i) who have professional experience in matters relating to investments falling within Article 19 (5) of the Financial Services and Markets Act 2000 (Financial Promotion) Order 2005, as amended (the “Order”) and/or (ii) who are high net worth companies (or persons to whom it may otherwise be lawfully communicated) falling within Article 49(2)(a) to (d) of the Order (all such persons together being referred to as “relevant persons”). This document must not be acted on or relied on in the United Kingdom by persons who are not relevant persons. In the United Kingdom, any investment or investment activity to which this document relates is only available to, and will be engaged in with, relevant persons.

Certain legal matters in connection with the common stock will be passed upon by Vinson & Elkins L.L.P., Houston, Texas, as our counsel. Certain legal matters will be passed upon for the underwriter by Andrews Kurth LLP, Houston, Texas.

The consolidated financial statements and management’s assessment of the effectiveness of internal control over financial reporting (which is included in Management’s Report on Internal Control Over Financial Reporting) incorporated in this prospectus supplement by reference to the Annual Report on Form 10-K of Oasis Petroleum Inc. for the year ended December 31, 2012 dated March 1, 2013 and the audited statements of revenues and direct operating expenses of the West Williston Acquisition assets included as Exhibit 99.1 to Oasis Petroleum Inc.’s Current Report on Form 8-K/A dated November 7, 2013 have been so incorporated in reliance on the reports of PricewaterhouseCoopers LLP, an independent registered public accounting firm, given on the authority of said firm as experts in auditing and accounting.

Estimated quantities of proved reserves of Oasis Petroleum Inc., the future net revenues from those reserves and their present value is based, in part, on estimates of the proved reserves and present values of proved reserves as of June 30, 2013 and December 31, 2010, 2011 and 2012. The reserve estimates at December 31, 2010, 2011 and 2012 for Oasis Petroleum Inc. are based on reports audited by DeGolyer and MacNaughton, independent reserve engineers. The reserve estimates at June 30, 2013 for Oasis Petroleum Inc., are based in part on a report audited by DeGolyer and MacNaughton. The reserve estimates at June 30, 2013 for the oil and gas properties acquired in the West Williston Acquisition, are based on a report prepared by DeGolyer and MacNaughton. We have incorporated these estimates in reliance on the authority of such firm as an expert in such matters.

We may offer and sell the securities listed above from time to time in one or more offerings in one or more classes or series. Any debt securities we offer pursuant to this prospectus may be fully and unconditionally guaranteed by certain of our subsidiaries, including Oasis Petroleum LLC and Oasis Petroleum North America LLC.

This prospectus provides you with a general description of the securities that may be offered. Each time securities are offered, we may provide a prospectus supplement and attach it to this prospectus. The prospectus supplement will contain more specific information about the offering and the terms of the securities being offered, including any guarantees by our subsidiaries. A prospectus supplement may also add, update or change information contained in this prospectus. This prospectus may not be used to offer or sell securities without a prospectus supplement describing the method and terms of the offering.

We may sell these securities directly or through agents, underwriters or dealers, or through a combination of these methods. See “Plan of Distribution.” The prospectus supplement will list any agents, underwriters or dealers that may be involved and the compensation they will receive. The prospectus supplement will also show you the total amount of money that we will receive from selling the securities being offered, after the expenses of the offering. You should carefully read this prospectus and any accompanying prospectus supplement, together with the documents we incorporate by reference, before you invest in any of our securities.

Investing in any of our securities involves risk. Please read carefully the information included and incorporated by reference in this prospectus and in any applicable prospectus supplement for a discussion of the factors you should consider before deciding to purchase our securities. See “Risk Factors” beginning on page 5 of this prospectus.

Our common stock is listed on the New York Stock Exchange (“NYSE”) under the symbol “OAS.”

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or determined if this prospectus is truthful or complete. Any representation to the contrary is a criminal offense.

You should rely only on the information contained in or incorporated by reference into this prospectus and any prospectus supplement. We have not authorized any dealer, salesman or other person to provide you with additional or different information. If anyone provides you with different or inconsistent information, you should not rely on it. This prospectus and any prospectus supplement are not an offer to sell or the solicitation of an offer to buy any securities other than the securities to which they relate and are not an offer to sell or the solicitation of an offer to buy securities in any jurisdiction to any person to whom it is unlawful to make an offer or solicitation in that jurisdiction. You should not assume that the information contained in this prospectus is accurate as of any date other than the date on the front cover of this prospectus, or that the information contained in any document incorporated by reference is accurate as of any date other than the date of the document incorporated by reference, regardless of the time of delivery of this prospectus or any sale of a security.

This prospectus is part of a registration statement that we filed with the Securities and Exchange Commission, which we refer to as the SEC, using a “shelf” registration process. Under this shelf registration process, we may offer and sell any combination of the securities described in this prospectus in one or more offerings. This prospectus provides you with a general description of the securities we may offer. Each time we sell securities, we will provide you with this prospectus and may provide you with a prospectus supplement that will contain specific information about the terms of the offering and the offered securities. That prospectus supplement may also add, update or change information contained in this prospectus. Any statement that we make in this prospectus will be modified or superseded by any inconsistent statement made by us in a prospectus supplement.

Additional information, including our financial statements and the notes thereto, is incorporated in this prospectus by reference to our reports filed with the SEC. Please read “Where You Can Find More Information” below. You are urged to read this prospectus carefully, including the “Risk Factors,” and our SEC reports in their entirety before investing in our securities.

Unless the context requires otherwise or unless otherwise noted, all references in this prospectus or any accompanying prospectus supplement to “Oasis,” “we” or “our” are to Oasis Petroleum Inc. and its subsidiaries.

We are an independent exploration and production company focused on the development and acquisition of unconventional oil and natural gas resources primarily in the Williston Basin. Since our inception, we have emphasized the acquisition of properties that provide current production and significant upside potential through further development. Our drilling activity is primarily directed toward projects that we believe can provide us with repeatable successes in the Bakken formation.

Our principal executive offices are located at 1001 Fannin Street, Suite 1500, Houston, Texas 77002, and our telephone number at that address is (281) 404-9500. Our common stock is listed on NYSE under the symbol “OAS.”

We file annual, quarterly and current reports and other information with the SEC (File No. 001-34776) pursuant to the Securities Exchange Act of 1934 (the “Exchange Act”). You may read and copy any documents that are filed at the SEC’s public reference room at 100 F Street, N.E., Washington, D.C. 20549. You may also obtain copies of these documents at prescribed rates from the public reference section of the SEC at its Washington address. Please call the SEC at 1-800-SEC-0330 for further information.

Our filings are also available to the public through the SEC’s website at http://www.sec.gov.

The SEC allows us to “incorporate by reference” information that we file with it, which means that we can disclose important information to you by referring you to documents previously filed with the SEC. The information incorporated by reference is an important part of this prospectus, and the information that we later file with the SEC will automatically update and supersede this information. The following documents we filed with the SEC pursuant to the Exchange Act are incorporated herein by reference:

These reports contain important information about us, our financial condition and our results of operations.

All future documents filed pursuant to Sections 13(a), 13(c), 14 and 15(d) of the Exchange Act (excluding any information furnished pursuant to Item 2.02 or Item 7.01 on any Current Report on Form 8-K) before the termination of each offering under this prospectus shall be deemed to be incorporated in this prospectus by reference and to be a part hereof from the date of filing of such documents. Any statement contained herein, or in a document incorporated or deemed to be incorporated by reference herein, shall be deemed to be modified or superseded for purposes of this prospectus to the extent that a statement contained herein or in any subsequently filed document that also is or is deemed to be incorporated by reference herein, modifies or supersedes such statement. Any such statement so modified or superseded shall not be deemed, except as so modified or superseded, to constitute a part of this prospectus.

You may request a copy of these filings at no cost by writing or telephoning us at the following address and telephone number:

We also maintain a website at http://www.oasispetroleum.com. However, the information on our website is not part of this prospectus.

This prospectus and the documents incorporated by reference contain forward-looking statements intended to qualify for the safe harbors from liability established by the Private Securities Litigation Reform Act of 1995, Section 27A of the Securities Act and Section 21E of the Exchange Act. These forward-looking statements are subject to a number of risks and uncertainties, many of which are beyond our control. All statements, other than statements of historical fact included in this prospectus and the documents incorporated by reference, regarding our strategy, future operations, financial position, estimated revenues and losses, projected costs, prospects, plans and objectives of management are forward-looking statements. When used in this prospectus, the words “could,” “believe,” “anticipate,” “intend,” “estimate,” “expect,” “may,” “continue,” “predict,” “potential,” “project” and similar expressions are intended to identify forward-looking statements, although not all forward-looking statements contain such identifying words. When considering forward looking statements, you should keep in mind the risk factors and other cautionary statements described under the heading “Risk Factors” included in this prospectus, and the risk factors and other cautionary statements described under the headings “Risk Factors” included in our most recent Annual Report on Form 10-K, any subsequently filed Quarterly Reports on Form 10-Q and any subsequently filed Current Reports on Form 8-K, all of which are incorporated by reference in this prospectus.

These forward looking statements are based on management’s current belief, based on currently available information, as to the outcome and timing of future events. Without limiting the generality of the foregoing, certain statements incorporated by reference or included in this prospectus constitute forward looking statements.

All forward-looking statements speak only as of the date they are made. You should not place undue reliance on these forward-looking statements. Although we believe that our plans, intentions and expectations reflected in or suggested by the forward-looking statements we make in this prospectus and the documents incorporated by reference are reasonable, we can give no assurance that these plans, intentions or expectations will be achieved. We disclose important factors that could cause our actual results to differ materially from our expectations under “Risk Factors” beginning on page 5 of this prospectus and those risk factors incorporated by reference to our most recent Annual Report on Form 10-K, any subsequently filed Quarterly Reports on Form 10-Q and any subsequently filed Current Reports on Form 8-K. These cautionary statements qualify all forward-looking statements attributable to us or persons acting on our behalf.

All subsequent written and oral forward-looking statements attributable to us or to persons acting on our behalf are expressly qualified in their entirety by the foregoing. We undertake no obligation to publicly release the results of any revisions to any such forward-looking statements that may be made to reflect events or circumstances after the date of this prospectus or to reflect the occurrence of unanticipated events. See also “Where You Can Find More Information.”

An investment in our securities involves a significant degree of risk. Before you invest in our securities you should carefully consider those risk factors included in our most recent Annual Report on Form 10-K, any subsequently filed Quarterly Reports on Form 10-Q and any subsequently filed Current Reports on Form 8-K, which are incorporated herein by reference, and those risk factors that may be included in any applicable prospectus supplement, together with all of the other information included in this prospectus, any prospectus supplement and the documents we incorporate by reference, in evaluating an investment in our securities. If any of the risks discussed in the foregoing documents were to occur, our business, financial condition, results of operations and cash flows could be materially adversely affected. Please read “Cautionary Statement Regarding Forward-Looking Statements.”

The following table sets forth our ratios of consolidated earnings to fixed charges for the periods presented:

For purposes of computing the ratio of earnings to fixed charges, “earnings” consists of pre-tax income from continuing operations before fixed charges. “Fixed charges” consists of interest expense, amortized capital expenses related to indebtedness and an estimate of interest within rental expense.

We had no preferred stock outstanding for any period presented, and accordingly, the ratio of earnings to combined fixed charges and preferred stock dividends is the same as the ratio of earnings to fixed charges.

Except as may be stated in any applicable prospectus supplement, we intend to use the net proceeds from any sales of securities by us under this prospectus for general corporate purposes, which may include repayment or refinancing of borrowings, working capital, capital expenditures, investments and acquisitions. Pending any specific application, we may initially invest funds in short-term marketable securities or apply them to repayments of indebtedness.

The Debt Securities will be either our senior debt securities (“Senior Debt Securities”) or our subordinated debt securities (“Subordinated Debt Securities”). The Senior Debt Securities and the Subordinated Debt Securities will be issued under separate indentures among us, the Subsidiary Guarantors of such Debt Securities, if any, and a trustee to be determined (the “Trustee”). Senior Debt Securities will be issued under a “Senior Indenture” and Subordinated Debt Securities will be issued under a “Subordinated Indenture.” Together, the Senior Indenture and the Subordinated Indenture are called “Indentures.”

The Debt Securities may be issued from time to time in one or more series. The particular terms of each series that are offered by a prospectus supplement will be described in the prospectus supplement.

Unless the Debt Securities are guaranteed by our subsidiaries as described below, the rights of Oasis and our creditors, including holders of the Debt Securities, to participate in the assets of any subsidiary upon the latter’s liquidation or reorganization, will be subject to the prior claims of the subsidiary’s creditors, except to the extent that we may ourself be a creditor with recognized claims against such subsidiary.

We have summarized selected provisions of the Indentures below. The summary is not complete. The form of each Indenture has been filed with the SEC as an exhibit to the registration statement of which this prospectus is a part, and you should read the Indentures for provisions that may be important to you. Capitalized terms used in the summary have the meanings specified in the Indentures.

The Indentures provide that Debt Securities in separate series may be issued thereunder from time to time without limitation as to aggregate principal amount. We may specify a maximum aggregate principal amount for the Debt Securities of any series. We will determine the terms and conditions of the Debt Securities, including the maturity, principal and interest, but those terms must be consistent with the Indenture. The Debt Securities will be our unsecured obligations.

The Subordinated Debt Securities will be subordinated in right of payment to the prior payment in full of all of our Senior Debt (as defined) as described under “— Subordination of Subordinated Debt Securities” and in the prospectus supplement applicable to any Subordinated Debt Securities. If the prospectus supplement so indicates, the Debt Securities will be convertible into our common stock.

If specified in the prospectus supplement respecting a particular series of Debt Securities, certain subsidiaries of Oasis (each a “Subsidiary Guarantor”) will fully and unconditionally guarantee (the “Subsidiary Guarantee”) that series as described under “— Subsidiary Guarantee” and in the prospectus supplement. Each Subsidiary Guarantee will be an unsecured obligation of the Subsidiary Guarantor. A Subsidiary Guarantee of Subordinated Debt Securities will be subordinated to the Senior Debt of the Subsidiary Guarantor on the same basis as the Subordinated Debt Securities are subordinated to our Senior Debt.

The applicable prospectus supplement will set forth the price or prices at which the Debt Securities to be issued will be offered for sale and will describe the following terms of such Debt Securities:

(2) whether the Debt Securities are Senior Debt Securities or Subordinated Debt Securities and, if Subordinated Debt Securities, the related subordination terms;

(3) whether any Subsidiary Guarantor will provide a Subsidiary Guarantee of the Debt Securities;

(6) the interest rate that the Debt Securities will bear and the interest payment dates for the Debt Securities;

(8) any terms upon which the Debt Securities may be redeemed, in whole or in part, at our option;

(9) any sinking fund or other provisions that would obligate us to redeem or otherwise repurchase the Debt Securities;

(10) the portion of the principal amount, if less than all, of the Debt Securities that will be payable upon declaration of acceleration of the Maturity of the Debt Securities;

(13) whether the Debt Securities are convertible into our common stock and, if so, the terms and conditions upon which conversion will be effected, including the initial conversion price or conversion rate and any adjustments thereto and the conversion period;

(14) any addition to or change in the covenants in the Indenture applicable to the Debt Securities; and

(15) any other terms of the Debt Securities not inconsistent with the provisions of the Indenture.

Debt Securities, including any Debt Securities that provide for an amount less than the principal amount thereof to be due and payable upon a declaration of acceleration of the Maturity thereof (“Original Issue Discount Securities”), may be sold at a substantial discount below their principal amount. Special United States federal income tax considerations applicable to Debt Securities sold at an original issue discount may be described in the applicable prospectus supplement. In addition, special United States federal income tax or other considerations applicable to any Debt Securities that are denominated in a currency or currency unit other than United States dollars may be described in the applicable prospectus supplement.

The indebtedness evidenced by the Subordinated Debt Securities will, to the extent set forth in the Subordinated Indenture with respect to each series of Subordinated Debt Securities, be subordinated in right of payment to the prior payment in full of all of our Senior Debt, including the Senior Debt Securities, and it may also be senior in right of payment to all of our Subordinated Debt. The prospectus supplement relating to any Subordinated Debt Securities will summarize the subordination provisions of the Subordinated Indenture applicable to that series including:

The prospectus supplement will also describe as of a recent date the approximate amount of Senior Debt to which the Subordinated Debt Securities of that series will be subordinated.

The failure to make any payment on any of the Subordinated Debt Securities by reason of the subordination provisions of the Subordinated Indenture described in the prospectus supplement will not be construed as preventing the occurrence of an Event of Default with respect to the Subordinated Debt Securities arising from any such failure to make payment.

The subordination provisions described above will not be applicable to payments in respect of the Subordinated Debt Securities from a defeasance trust established in connection with any legal defeasance or

covenant defeasance of the Subordinated Debt Securities as described under “— Legal Defeasance and Covenant Defeasance.”

If specified in the prospectus supplement, one or more of the Subsidiary Guarantors will guarantee the Debt Securities of a series. Unless otherwise indicated in the prospectus supplement, the following provisions will apply to the Subsidiary Guarantee of the Subsidiary Guarantor.

Subject to the limitations described below and in the prospectus supplement, one or more of the Subsidiary Guarantors will jointly and severally, fully and unconditionally guarantee the punctual payment when due, whether at Stated Maturity, by acceleration or otherwise, of all our payment obligations under the Indentures and the Debt Securities of a series, whether for principal of, premium, if any, or interest on the Debt Securities or otherwise (all such obligations guaranteed by a Subsidiary Guarantor being herein called the “Guaranteed Obligations”). The Subsidiary Guarantors will also pay all expenses (including reasonable counsel fees and expenses) incurred by the applicable Trustee in enforcing any rights under a Subsidiary Guarantee with respect to a Subsidiary Guarantor.

In the case of Subordinated Debt Securities, a Subsidiary Guarantor’s Subsidiary Guarantee will be subordinated in right of payment to the Senior Debt of such Subsidiary Guarantor on the same basis as the Subordinated Debt Securities are subordinated to our Senior Debt. No payment will be made by any Subsidiary Guarantor under its Subsidiary Guarantee during any period in which payments by us on the Subordinated Debt Securities are suspended by the subordination provisions of the Subordinated Indenture.

Each Subsidiary Guarantee will be limited in amount to an amount not to exceed the maximum amount that can be guaranteed by the relevant Subsidiary Guarantor without rendering such Subsidiary Guarantee voidable under applicable law relating to fraudulent conveyance or fraudulent transfer or similar laws affecting the rights of creditors generally.

(1) remain in full force and effect until either (a) payment in full of all the applicable Debt Securities (or such Debt Securities are otherwise satisfied and discharged in accordance with the provisions of the applicable Indenture) or (b) released as described in the following paragraph;

(3) inure to the benefit of and be enforceable by the applicable Trustee, the Holders and their successors, transferees and assigns.

In the event that (a) a Subsidiary Guarantor ceases to be a Subsidiary, (b) either legal defeasance or covenant defeasance occurs with respect to the series or (c) all or substantially all of the assets or all of the Capital Stock of such Subsidiary Guarantor is sold, including by way of sale, merger, consolidation or otherwise, such Subsidiary Guarantor will be released and discharged of its obligations under its Subsidiary Guarantee without any further action required on the part of the Trustee or any Holder, and no other person acquiring or owning the assets or Capital Stock of such Subsidiary Guarantor will be required to enter into a Subsidiary Guarantee. In addition, the prospectus supplement may specify additional circumstances under which a Subsidiary Guarantor can be released from its Subsidiary Guarantee.

The Debt Securities of each series will be issuable only in fully registered form, without coupons, and, unless otherwise specified in the applicable prospectus supplement, only in denominations of $1,000 and integral multiples thereof.

At the option of the Holder, subject to the terms of the applicable Indenture and the limitations applicable to Global Securities, Debt Securities of each series will be exchangeable for other Debt Securities of the same series of any authorized denomination and of a like tenor and aggregate principal amount.

Subject to the terms of the applicable Indenture and the limitations applicable to Global Securities, Debt Securities may be presented for exchange as provided above or for registration of transfer (duly endorsed or with the form of transfer endorsed thereon duly executed) at the office of the Security Registrar or at the office of any transfer agent designated by us for such purpose. No service charge will be made for any registration of transfer or exchange of Debt Securities, but we may require payment of a sum sufficient to cover any tax or other governmental charge payable in that connection. Such transfer or exchange will be effected upon the Security Registrar or such transfer agent, as the case may be, being satisfied with the documents of title and identity of the person making the request. The Security Registrar and any other transfer agent initially designated by us for any Debt Securities will be named in the applicable prospectus supplement. We may at any time designate additional transfer agents or rescind the designation of any transfer agent or approve a change in the office through which any transfer agent acts, except that we will be required to maintain a transfer agent in each Place of Payment for the Debt Securities of each series.

If the Debt Securities of any series (or of any series and specified tenor) are to be redeemed in part, we will not be required to (1) issue, register the transfer of or exchange any Debt Security of that series (or of that series and specified tenor, as the case may be) during a period beginning at the opening of business 15 days before the day of mailing of a notice of redemption of any such Debt Security that may be selected for redemption and ending at the close of business on the day of such mailing or (2) register the transfer of or exchange any Debt Security so selected for redemption, in whole or in part, except the unredeemed portion of any such Debt Security being redeemed in part.

Some or all of the Debt Securities of any series may be represented, in whole or in part, by one or more Global Securities that will have an aggregate principal amount equal to that of the Debt Securities they represent. Each Global Security will be registered in the name of a Depositary or its nominee identified in the applicable prospectus supplement, will be deposited with such Depositary or nominee or its custodian and will bear a legend regarding the restrictions on exchanges and registration of transfer thereof referred to below and any such other matters as may be provided for pursuant to the applicable Indenture.

Notwithstanding any provision of the Indentures or any Debt Security described in this prospectus, no Global Security may be exchanged in whole or in part for Debt Securities registered, and no transfer of a Global Security in whole or in part may be registered, in the name of any Person other than the Depositary for such Global Security or any nominee of such Depositary unless:

(1) the Depositary has notified us that it is unwilling or unable to continue as Depositary for such Global Security or has ceased to be qualified to act as such as required by the applicable Indenture, and in either case we fail to appoint a successor Depositary within 90 days;

(2) an Event of Default with respect to the Debt Securities represented by such Global Security has occurred and is continuing and the Trustee has received a written request from the Depositary to issue certificated Debt Securities;

(3) subject to the rules of the Depositary, we shall have elected to terminate the book-entry system through the Depositary; or

(4) other circumstances exist, in addition to or in lieu of those described above, as may be described in the applicable prospectus supplement.

All certificated Debt Securities issued in exchange for a Global Security or any portion thereof will be registered in such names as the Depositary may direct.

As long as the Depositary, or its nominee, is the registered holder of a Global Security, the Depositary or such nominee, as the case may be, will be considered the sole owner and Holder of such Global Security and the Debt Securities that it represents for all purposes under the Debt Securities and the applicable Indenture. Except in the limited circumstances referred to above, owners of beneficial interests in a Global Security will not be entitled to have such Global Security or any Debt Securities that it represents registered in their names, will not receive or be entitled to receive physical delivery of certificated Debt Securities in exchange for those interests

and will not be considered to be the owners or Holders of such Global Security or any Debt Securities that is represents for any purpose under the Debt Securities or the applicable Indenture. All payments on a Global Security will be made to the Depositary or its nominee, as the case may be, as the Holder of the security. The laws of some jurisdictions may require that some purchasers of Debt Securities take physical delivery of such Debt Securities in certificated form. These laws may impair the ability to transfer beneficial interests in a Global Security.

Ownership of beneficial interests in a Global Security will be limited to institutions that have accounts with the Depositary or its nominee (“participants”) and to persons that may hold beneficial interests through participants. In connection with the issuance of any Global Security, the Depositary will credit, on its book-entry registration and transfer system, the respective principal amounts of Debt Securities represented by the Global Security to the accounts of its participants. Ownership of beneficial interests in a Global Security will be shown only on, and the transfer of those ownership interests will be effected only through, records maintained by the Depositary (with respect to participants’ interests) or any such participant (with respect to interests of Persons held by such participants on their behalf). Payments, transfers, exchanges and other matters relating to beneficial interests in a Global Security may be subject to various policies and procedures adopted by the Depositary from time to time. None of us, the Subsidiary Guarantors, the Trustees or the agents of us, the Subsidiary Guarantors or the Trustees will have any responsibility or liability for any aspect of the Depositary’s or any participant’s records relating to, or for payments made on account of, beneficial interests in a Global Security, or for maintaining, supervising or reviewing any records relating to such beneficial interests.

Unless otherwise indicated in the applicable prospectus supplement, payment of interest on a Debt Security on any Interest Payment Date will be made to the Person in whose name such Debt Security (or one or more Predecessor Securities) is registered at the close of business on the Regular Record Date for such interest.

Unless otherwise indicated in the applicable prospectus supplement, principal of and any premium and interest on the Debt Securities of a particular series will be payable at the office of such Paying Agent or Paying Agents as we may designate for such purpose from time to time, except that at our option payment of any interest on Debt Securities in certificated form may be made by check mailed to the address of the Person entitled thereto as such address appears in the Security Register. Unless otherwise indicated in the applicable prospectus supplement, the corporate trust office of the Trustee under the Senior Indenture in The City of New York will be designated as sole Paying Agent for payments with respect to Senior Debt Securities of each series, and the corporate trust office of the Trustee under the Subordinated Indenture in The City of New York will be designated as the sole Paying Agent for payment with respect to Subordinated Debt Securities of each series. Any other Paying Agents initially designated by us for the Debt Securities of a particular series will be named in the applicable prospectus supplement. We may at any time designate additional Paying Agents or rescind the designation of any Paying Agent or approve a change in the office through which any Paying Agent acts, except that we will be required to maintain a Paying Agent in each Place of Payment for the Debt Securities of a particular series.

All money paid by us to a Paying Agent for the payment of the principal of or any premium or interest on any Debt Security which remains unclaimed at the end of two years after such principal, premium or interest has become due and payable will be repaid to us, and the Holder of such Debt Security thereafter may look only to us for payment.

Unless otherwise specified in the prospectus supplement, we may not consolidate with or merge into, or transfer, lease or otherwise dispose of all or substantially all of our assets to, any Person (a “successor Person”), and may not permit any Person to consolidate with or merge into us, unless:

(1) the successor Person (if not us) is a corporation, partnership, trust or other entity organized and validly existing under the laws of any domestic jurisdiction and assumes our obligations on the Debt Securities and under the Indentures;

(2) immediately before and after giving pro forma effect to the transaction, no Event of Default, and no event which, after notice or lapse of time or both, would become an Event of Default, has occurred and is continuing; and

(3) several other conditions, including any additional conditions with respect to any particular Debt Securities specified in the applicable prospectus supplement, are met.

The successor Person (if not us) will be substituted for us under the applicable Indenture with the same effect as if it had been an original party to such Indenture, and, except in the case of a lease, we will be relieved from any further obligations under such Indenture and the Debt Securities.

Unless otherwise specified in the prospectus supplement, each of the following will constitute an Event of Default under the applicable Indenture with respect to Debt Securities of any series:

(1) failure to pay principal of or any premium on any Debt Security of that series when due, whether or not, in the case of Subordinated Debt Securities, such payment is prohibited by the subordination provisions of the Subordinated Indenture;

(2) failure to pay any interest on any Debt Securities of that series when due, continued for 30 days, whether or not, in the case of Subordinated Debt Securities, such payment is prohibited by the subordination provisions of the Subordinated Indenture;

(3) failure to deposit any sinking fund payment, when due, in respect of any Debt Security of that series, whether or not, in the case of Subordinated Debt Securities, such deposit is prohibited by the subordination provisions of the Subordinated Indenture;

(4) failure to perform or comply with the provisions described under “— Consolidation, Merger and Sale of Assets”;

(5) failure to perform any of our other covenants in such Indenture (other than a covenant included in such Indenture solely for the benefit of a series other than that series), continued for 60 days after written notice has been given by the applicable Trustee, or the Holders of at least 25% in principal amount of the Outstanding Debt Securities of that series, as provided in such Indenture;

(6) any Debt of ourself, any Significant Subsidiary or, if a Subsidiary Guarantor has guaranteed the series, such Subsidiary Guarantor, is not paid within any applicable grace period after final maturity or is accelerated by its holders because of a default and the total amount of such Debt unpaid or accelerated exceeds $20.0 million;

(7) any judgment or decree for the payment of money in excess of $20.0 million is entered against us, any Significant Subsidiary or, if a Subsidiary Guarantor has guaranteed the series, such Subsidiary Guarantor, remains outstanding for a period of 60 consecutive days following entry of such judgment and is not discharged, waived or stayed;

(8) certain events of bankruptcy, insolvency or reorganization affecting us, any Significant Subsidiary or, if a Subsidiary Guarantor has guaranteed the series, such Subsidiary Guarantor; and

(9) if any Subsidiary Guarantor has guaranteed such series, the Subsidiary Guarantee of any such Subsidiary Guarantor is held by a final non-appealable order or judgment of a court of competent jurisdiction to be unenforceable or invalid or ceases for any reason to be in full force and effect (other than in accordance with the terms of the applicable Indenture) or any Subsidiary Guarantor or any Person acting on behalf of any Subsidiary Guarantor denies or disaffirms such Subsidiary Guarantor’s obligations under its Subsidiary Guarantee (other than by reason of a release of such Subsidiary Guarantor from its Subsidiary Guarantee in accordance with the terms of the applicable Indenture).

If an Event of Default (other than an Event of Default with respect to Oasis Petroleum Inc. described in clause (8) above) with respect to the Debt Securities of any series at the time Outstanding occurs and is continuing, either the applicable Trustee or the Holders of at least 25% in principal amount of the Outstanding

Debt Securities of that series by notice as provided in the Indenture may declare the principal amount of the Debt Securities of that series (or, in the case of any Debt Security that is an Original Issue Discount Debt Security, such portion of the principal amount of such Debt Security as may be specified in the terms of such Debt Security) to be due and payable immediately, together with any accrued and unpaid interest thereon. If an Event of Default with respect to Oasis Petroleum Inc. described in clause (8) above with respect to the Debt Securities of any series at the time Outstanding occurs, the principal amount of all the Debt Securities of that series (or, in the case of any such Original Issue Discount Security, such specified amount) will automatically, and without any action by the applicable Trustee or any Holder, become immediately due and payable, together with any accrued and unpaid interest thereon. After any such acceleration and its consequences, but before a judgment or decree based on acceleration, the Holders of a majority in principal amount of the Outstanding Debt Securities of that series may, under certain circumstances, rescind and annul such acceleration if all Events of Default with respect to that series, other than the non-payment of accelerated principal (or other specified amount), have been cured or waived as provided in the applicable Indenture. For information as to waiver of defaults, see “— Modification and Waiver” below.

Subject to the provisions of the Indentures relating to the duties of the Trustees in case an Event of Default has occurred and is continuing, no Trustee will be under any obligation to exercise any of its rights or powers under the applicable Indenture at the request or direction of any of the Holders, unless such Holders have offered to such Trustee reasonable security or indemnity. Subject to such provisions for the indemnification of the Trustees, the Holders of a majority in principal amount of the Outstanding Debt Securities of any series will have the right to direct the time, method and place of conducting any proceeding for any remedy available to the Trustee or exercising any trust or power conferred on the Trustee with respect to the Debt Securities of that series.

No Holder of a Debt Security of any series will have any right to institute any proceeding with respect to the applicable Indenture, or for the appointment of a receiver or a trustee, or for any other remedy thereunder, unless:

(1) such Holder has previously given to the Trustee under the applicable Indenture written notice of a continuing Event of Default with respect to the Debt Securities of that series;

(2) the Holders of at least 25% in principal amount of the Outstanding Debt Securities of that series have made written request, and such Holder or Holders have offered reasonable security or indemnity, to the Trustee to institute such proceeding as trustee; and

(3) the Trustee has failed to institute such proceeding, and has not received from the Holders of a majority in principal amount of the Outstanding Debt Securities of that series a direction inconsistent with such request, within 60 days after such notice, request and offer.

However, such limitations do not apply to a suit instituted by a Holder of a Debt Security for the enforcement of payment of the principal of or any premium or interest on such Debt Security on or after the applicable due date specified in such Debt Security or, if applicable, to convert such Debt Security.

We will be required to furnish to each Trustee annually a statement by certain of our officers as to whether or not we, to their knowledge, are in default in the performance or observance of any of the terms, provisions and conditions of the applicable Indenture and, if so, specifying all such known defaults.

We may modify or amend an Indenture without the consent of any holders of the Debt Securities in certain circumstances, including:

(1) to evidence the succession under the Indenture of another Person to us or any Subsidiary Guarantor and to provide for its assumption of our or such Subsidiary Guarantor’s obligations to holders of Debt Securities;

(2) to make any changes that would add any additional covenants of us or the Subsidiary Guarantors for the benefit of the holders of Debt Securities or that do not adversely affect the rights under the Indenture of the Holders of Debt Securities in any material respect;

(4) to provide for uncertificated notes in addition to or in place of certificated notes;

(7) to evidence and provide for the acceptance of appointment under the Indenture of a successor Trustee;

(10) in the case of any Subordinated Debt Security, to make any change in the subordination provisions that limits or terminates the benefits applicable to any Holder of Senior Debt.

Other modifications and amendments of an Indenture may be made by us, the Subsidiary Guarantors, if applicable, and the applicable Trustee with the consent of the Holders of a majority in principal amount of the Outstanding Debt Securities of each series affected by such modification or amendment; provided, however, that no such modification or amendment may, without the consent of the Holder of each Outstanding Debt Security affected thereby:

(1) change the Stated Maturity of the principal of, or any installment of principal of or interest on, any Debt Security;

(2) reduce the principal amount of, or any premium or interest on, any Debt Security;

(3) reduce the amount of principal of an Original Issue Discount Security or any other Debt Security payable upon acceleration of the Maturity thereof;

(4) change the place or currency of payment of principal of, or any premium or interest on, any Debt Security;

(5) impair the right to institute suit for the enforcement of any payment due on or any conversion right with respect to any Debt Security;

(6) modify the subordination provisions in the case of Subordinated Debt Securities, or modify any conversion provisions, in either case in a manner adverse to the Holders of the Subordinated Debt Securities;

(7) except as provided in the applicable Indenture, release the Subsidiary Guarantee of a Subsidiary Guarantor;

(8) reduce the percentage in principal amount of Outstanding Debt Securities of any series, the consent of whose Holders is required for modification or amendment of the Indenture;

(9) reduce the percentage in principal amount of Outstanding Debt Securities of any series necessary for waiver of compliance with certain provisions of the Indenture or for waiver of certain defaults;

(10) modify such provisions with respect to modification, amendment or waiver; or

(11) following the making of an offer to purchase Debt Securities from any Holder that has been made pursuant to a covenant in such Indenture, modify such covenant in a manner adverse to such Holder.

The Holders of a majority in principal amount of the Outstanding Debt Securities of any series may waive compliance by us with certain restrictive provisions of the applicable Indenture. The Holders of a majority in principal amount of the Outstanding Debt Securities of any series may waive any past default under the applicable Indenture, except a default in the payment of principal, premium or interest and certain covenants and provisions of the Indenture which cannot be amended without the consent of the Holder of each Outstanding Debt Security of such series.

Each of the Indentures provides that in determining whether the Holders of the requisite principal amount of the Outstanding Debt Securities have given or taken any direction, notice, consent, waiver or other action under such Indenture as of any date:

(1) the principal amount of an Original Issue Discount Security that will be deemed to be Outstanding will be the amount of the principal that would be due and payable as of such date upon acceleration of maturity to such date;

(2) if, as of such date, the principal amount payable at the Stated Maturity of a Debt Security is not determinable (for example, because it is based on an index), the principal amount of such Debt Security deemed to be Outstanding as of such date will be an amount determined in the manner prescribed for such Debt Security;

(3) the principal amount of a Debt Security denominated in one or more foreign currencies or currency units that will be deemed to be Outstanding will be the United States-dollar equivalent, determined as of such date in the manner prescribed for such Debt Security, of the principal amount of such Debt Security (or, in the case of a Debt Security described in clause (1) or (2) above, of the amount described in such clause); and

(4) certain Debt Securities, including those owned by us, any Subsidiary Guarantor or any of our other Affiliates, will not be deemed to be Outstanding.

Except in certain limited circumstances, we will be entitled to set any day as a record date for the purpose of determining the Holders of Outstanding Debt Securities of any series entitled to give or take any direction, notice, consent, waiver or other action under the applicable Indenture, in the manner and subject to the limitations provided in the Indenture. In certain limited circumstances, the Trustee will be entitled to set a record date for action by Holders. If a record date is set for any action to be taken by Holders of a particular series, only persons who are Holders of Outstanding Debt Securities of that series on the record date may take such action. To be effective, such action must be taken by Holders of the requisite principal amount of such Debt Securities within a specified period following the record date. For any particular record date, this period will be 180 days or such other period as may be specified by us (or the Trustee, if it set the record date), and may be shortened or lengthened (but not beyond 180 days) from time to time.

Each Indenture will be discharged and will cease to be of further effect as to all outstanding Debt Securities of any series issued thereunder, when:

(a) all outstanding Debt Securities of that series that have been authenticated (except lost, stolen or destroyed Debt Securities that have been replaced or paid and Debt Securities for whose payment money has theretofore been deposited in trust and thereafter repaid to us) have been delivered to the Trustee for cancellation; or

(b) all outstanding Debt Securities of that series that have been not delivered to the Trustee for cancellation have become due and payable or will become due and payable at their Stated Maturity within one year or are to be called for redemption within one year under arrangements satisfactory to the Trustee and in any case we have irrevocably deposited with the Trustee as trust funds money in an amount sufficient, without consideration of any reinvestment of interest, to pay the entire indebtedness of such Debt Securities not delivered to the Trustee for cancellation, for principal, premium, if any, and accrued interest to the Stated Maturity or redemption date;

(2) we have paid or caused to be paid all other sums payable by us under the Indenture with respect to the Debt Securities of that series; and

(3) we have delivered an Officers’ Certificate and an Opinion of Counsel to the Trustee stating that all conditions precedent to satisfaction and discharge of the Indenture with respect to the Debt Securities of that series have been satisfied.

To the extent indicated in the applicable prospectus supplement, we may elect, at our option at any time, to have our obligations discharged under provisions relating to defeasance and discharge of indebtedness, which we call “legal defeasance,” or relating to defeasance of certain restrictive covenants applied to the Debt Securities of any series, or to any specified part of a series, which we call “covenant defeasance”.

Legal Defeasance. The Indentures provide that, upon our exercise of our option (if any) to have the legal defeasance provisions applied to any series of Debt Securities, we and, if applicable, each Subsidiary Guarantor will be discharged from all our obligations, and, if such Debt Securities are Subordinated Debt Securities, the provisions of the Subordinated Indenture relating to subordination will cease to be effective, with respect to such Debt Securities (except for certain obligations to convert, exchange or register the transfer of Debt Securities, to replace stolen, lost or mutilated Debt Securities, to maintain paying agencies and to hold moneys for payment in trust) upon the deposit in trust for the benefit of the Holders of such Debt Securities of money or U.S. Government Obligations, or both, which, through the payment of principal and interest in respect thereof in accordance with their terms, will provide money in an amount sufficient (in the opinion of a nationally recognized firm of independent public accountants) to pay the principal of and any premium and interest on such Debt Securities on the respective Stated Maturities in accordance with the terms of the applicable Indenture and such Debt Securities. Such defeasance or discharge may occur only if, among other things:

(1) we have delivered to the applicable Trustee an Opinion of Counsel to the effect that we have received from, or there has been published by, the United States Internal Revenue Service a ruling, or there has been a change in tax law, in either case to the effect that Holders of such Debt Securities will not recognize gain or loss for federal income tax purposes as a result of such deposit and legal defeasance and will be subject to federal income tax on the same amount, in the same manner and at the same times as would have been the case if such deposit and legal defeasance were not to occur;

(2) no Event of Default or event that with the passing of time or the giving of notice, or both, shall constitute an Event of Default shall have occurred and be continuing at the time of such deposit or, with respect to any Event of Default described in clause (8) under “— Events of Default,” at any time until 121 days after such deposit;

(3) such deposit and legal defeasance will not result in a breach or violation of, or constitute a default under, any agreement or instrument (other than the applicable Indenture) to which we are a party or by which we are bound;

(4) in the case of Subordinated Debt Securities, at the time of such deposit, no default in the payment of all or a portion of principal of (or premium, if any) or interest on any Senior Debt shall have occurred and be continuing, no event of default shall have resulted in the acceleration of any Senior Debt and no other event of default with respect to any Senior Debt shall have occurred and be continuing permitting after notice or the lapse of time, or both, the acceleration thereof; and

(5) we have delivered to the Trustee an Opinion of Counsel to the effect that such deposit shall not cause the Trustee or the trust so created to be subject to the Investment Company Act of 1940.

Covenant Defeasance. The Indentures provide that, upon our exercise of our option (if any) to have the covenant defeasance provisions applied to any Debt Securities, we may fail to comply with certain restrictive covenants (but not with respect to conversion, if applicable), including those that may be described in the applicable prospectus supplement, and the occurrence of certain Events of Default, which are described above in clause (5) (with respect to such restrictive covenants) and clauses (6), (7) and (9) under “Events of Default” and any that may be described in the applicable prospectus supplement, will not be deemed to either be or result in an Event of Default and, if such Debt Securities are Subordinated Debt Securities, the provisions of the Subordinated Indenture relating to subordination will cease to be effective, in each case with respect to such Debt Securities. In order to exercise such option, we must deposit, in trust for the benefit of the Holders of such Debt Securities, money or U.S. Government Obligations, or both, which, through the payment of principal and interest in respect thereof in accordance with their terms, will provide money in an amount sufficient (in the opinion of a nationally recognized firm of independent public accountants) to pay the principal of and any premium and interest on such Debt Securities on the respective Stated Maturities in accordance with the terms of the applicable

Indenture and such Debt Securities. Such covenant defeasance may occur only if we have delivered to the applicable Trustee an Opinion of Counsel to the effect that Holders of such Debt Securities will not recognize gain or loss for federal income tax purposes as a result of such deposit and covenant defeasance and will be subject to federal income tax on the same amount, in the same manner and at the same times as would have been the case if such deposit and covenant defeasance were not to occur, and the requirements set forth in clauses (2), (3), (4) and (5) above are satisfied. If we exercise this option with respect to any series of Debt Securities and such Debt Securities were declared due and payable because of the occurrence of any Event of Default, the amount of money and U.S. Government Obligations so deposited in trust would be sufficient to pay amounts due on such Debt Securities at the time of their respective Stated Maturities but may not be sufficient to pay amounts due on such Debt Securities upon any acceleration resulting from such Event of Default. In such case, we would remain liable for such payments.

If we exercise either our legal defeasance or covenant defeasance option, any Subsidiary Guarantee will terminate.

No director, officer, employee, incorporator, stockholder, member, partner or trustee of the Company or any Subsidiary Guarantor, as such, shall have any liability for any obligations of the Company or any Subsidiary Guarantor under the Debt Securities, the Indentures or any Subsidiary Guarantees or for any claim based on, in respect of, or by reason of, such obligations or their creation. By accepting a Debt Security, each Holder shall be deemed to have waived and released all such liability. The waiver and release shall be a part of the consideration for the issue of the Debt Securities. The waiver may not be effective to waive liabilities under the federal securities laws, and it is the view of the SEC that such a waiver is against public policy.

Notices to Holders of Debt Securities will be given by mail to the addresses of such Holders as they may appear in the Security Register.

We, the Subsidiary Guarantors, the Trustees and any agent of us, the Subsidiary Guarantors or a Trustee may treat the Person in whose name a Debt Security is registered as the absolute owner of the Debt Security (whether or not such Debt Security may be overdue) for the purpose of making payment and for all other purposes.

The Indentures and the Debt Securities will be governed by, and construed in accordance with, the law of the State of New York.

We will enter into the Indentures with a Trustee that is qualified to act under the Trust Indenture Act of 1939, as amended, and with any other Trustees chosen by us and appointed in a supplemental indenture for a particular series of Debt Securities. We may maintain a banking relationship in the ordinary course of business with our Trustee and one or more of its affiliates.

Resignation or Removal of Trustee. If the Trustee has or acquires a conflicting interest within the meaning of the Trust Indenture Act, the Trustee must either eliminate its conflicting interest or resign, to the extent and in the manner provided by, and subject to the provisions of, the Trust Indenture Act and the applicable Indenture. Any resignation will require the appointment of a successor Trustee under the applicable Indenture in accordance with the terms and conditions of such Indenture.

The Trustee may resign or be removed by us with respect to one or more series of Debt Securities and a successor Trustee may be appointed to act with respect to any such series. The holders of a majority in aggregate principal amount of the Debt Securities of any series may remove the Trustee with respect to the Debt Securities of such series.

Limitations on Trustee if It Is Our Creditor. Each Indenture will contain certain limitations on the right of the Trustee, in the event that it becomes our creditor, to obtain payment of claims in certain cases, or to realize on certain property received in respect of any such claim as security or otherwise.

Certificates and Opinions to Be Furnished to Trustee. Each Indenture will provide that, in addition to other certificates or opinions that may be specifically required by other provisions of an Indenture, every application by us for action by the Trustee must be accompanied by an Officers’ Certificate and an Opinion of Counsel stating that, in the opinion of the signers, all conditions precedent to such action have been complied with by us.

The authorized capital stock of Oasis Petroleum Inc. consists of 300,000,000 shares of common stock, $0.01 par value per share, and 50,000,000 shares of preferred stock, $0.01 par value per share.

We adopted an amended and restated certificate of incorporation (the “Amended Charter”) and amended and restated bylaws (the “Amended Bylaws”) concurrently with the completion of our initial public offering. The following summary of the capital stock and Amended Charter and Amended Bylaws of Oasis Petroleum Inc. does not purport to be complete and is qualified in its entirety by reference to the provisions of applicable law and to our Amended Charter and Amended Bylaws, which are filed as exhibits to the registration statement filed in connection with our initial public offering.

As of June 30, 2011, we had 92,450,195 shares of common stock outstanding, all of which is voting common stock.

Except as provided by law or in a preferred stock designation, holders of common stock are entitled to one vote for each share held of record on all matters submitted to a vote of the stockholders, will have the exclusive right to vote for the election of directors and do not have cumulative voting rights. Except as otherwise required by law, holders of common stock, as such, are not entitled to vote on any amendment to the Amended Charter (including any certificate of designations relating to any series of preferred stock) that relates solely to the terms of any outstanding series of preferred stock if the holders of such affected series are entitled, either separately or together with the holders of one or more other such series, to vote thereon pursuant to the Amended Charter (including any certificate of designations relating to any series of preferred stock) or pursuant to the General Corporation Law of the State of Delaware. Subject to preferences that may be applicable to any outstanding shares or series of preferred stock, holders of common stock are entitled to receive ratably such dividends (payable in cash, stock or otherwise), if any, as may be declared from time to time by our board of directors out of funds legally available for dividend payments. All outstanding shares of common stock are fully paid and non-assessable, and the shares of common stock to be issued upon completion of this offering will be fully paid and non-assessable. The holders of common stock have no preferences or rights of conversion, exchange, pre-emption or other subscription rights. There are no redemption or sinking fund provisions applicable to the common stock. In the event of any liquidation, dissolution or winding-up of our affairs, holders of common stock will be entitled to share ratably in our assets that are remaining after payment or provision for payment of all of our debts and obligations and after liquidation payments to holders of outstanding shares of preferred stock, if any.

Our Amended Charter authorizes our board of directors, subject to any limitations prescribed by law, without further stockholder approval, to establish and to issue from time to time one or more classes or series of preferred stock, par value $0.01 per share, covering up to an aggregate of 50,000,000 shares of preferred stock. Each class or series of preferred stock will cover the number of shares and will have the powers, preferences, rights, qualifications, limitations and restrictions determined by the board of directors, which may include, among others, dividend rights, liquidation preferences, voting rights, conversion rights, preemptive rights and redemption rights. Except as provided by law or in a preferred stock designation, the holders of preferred stock will not be entitled to vote at or receive notice of any meeting of stockholders.

Anti-Takeover Effects of Provisions of Our Amended Charter, Our Amended Bylaws and Delaware Law

Some provisions of Delaware law, and our Amended Charter and our Amended Bylaws described below, contains provisions that could make the following transactions more difficult: acquisitions of us by means of a tender offer, a proxy contest or otherwise; or removal of our incumbent officers and directors. These provisions may also have the effect of preventing changes in our management. It is possible that these provisions could make it more difficult to accomplish or could deter transactions that stockholders may otherwise consider to be in their best interest or in our best interests, including transactions that might result in a premium over the market price for our shares.

These provisions, summarized below, are expected to discourage coercive takeover practices and inadequate takeover bids. These provisions are also designed to encourage persons seeking to acquire control of us to first negotiate with us. We believe that the benefits of increased protection and our potential ability to negotiate with the proponent of an unfriendly or unsolicited proposal to acquire or restructure us outweigh the disadvantages of discouraging these proposals because, among other things, negotiation of these proposals could result in an improvement of their terms.

We are subject to the provisions of Section 203 of the Delaware General Corporation Law, or DGCL, regulating corporate takeovers. In general, those provisions prohibit a Delaware corporation, including those whose securities are listed for trading on the NYSE, from engaging in any business combination with any interested stockholder for a period of three years following the date that the stockholder became an interested stockholder, unless:

In general, Section 203 defines an interested stockholder as any entity or person beneficially owning 15% or more of the outstanding voting stock of the corporation and any entity or person affiliated with or controlling or controlled by any of these entities or persons.

A Delaware corporation may “opt out” of Section 203 with an express provision in its original certificate of incorporation or an express provision in its certificate of incorporation or bylaws resulting from amendments approved by the holders of at least a majority of the corporation’s outstanding voting shares. We did not “opt out” of the provisions of Section 203. The statute could prohibit or delay mergers or other takeover or change in control attempts and, accordingly, may discourage attempts to acquire us.

These procedures provide that notice of stockholder proposals must be timely given in writing to our corporate secretary prior to the meeting at which the action is to be taken. Generally, to be timely, notice must be received at our principal executive offices not less than 90 days nor more than 120 days prior to the first anniversary date of the annual meeting for the preceding year. Our Amended Bylaws specify the requirements as to form and content of all stockholders’ notices. These requirements may preclude stockholders from bringing matters before the stockholders at an annual or special meeting;

Our Amended Charter limits the liability of our directors for monetary damages for breach of their fiduciary duty as directors, except for liability that cannot be eliminated under the DGCL. Delaware law provides that

directors of a company will not be personally liable for monetary damages for breach of their fiduciary duty as directors, except for liabilities:

Any amendment, repeal or modification of these provisions will be prospective only and would not affect any limitation on liability of a director for acts or omissions that occurred prior to any such amendment, repeal or modification.

Our Amended Charter and Amended Bylaws also provide that we will indemnify our directors and officers to the fullest extent permitted by Delaware law. Our Amended Charter and Amended Bylaws also permit us to purchase insurance on behalf of any officer, director, employee or other agent for any liability arising out of that person’s actions as our officer, director, employee or agent, regardless of whether Delaware law would permit indemnification. We intend to enter into indemnification agreements with each of our current and future directors and officers. These agreements will require us to indemnify these individuals to the fullest extent permitted under Delaware law against liability that may arise by reason of their service to us, and to advance expenses incurred as a result of any proceeding against them as to which they could be indemnified. We believe that the limitation of liability provision in our Amended Charter and the indemnification agreements will facilitate our ability to continue to attract and retain qualified individuals to serve as directors and officers.

Our Amended Charter provides that, to the fullest extent permitted by applicable law, we renounce any interest or expectancy in, or in being offered an opportunity to participate in, any business opportunity that may be from time to time presented to EnCap or its affiliates or any of their respective officers, directors, agents, shareholders, members, partners, affiliates and subsidiaries (other than us and our subsidiaries) or business opportunities that such parties participate in or desire to participate in, even if the opportunity is one that we might reasonably have pursued or had the ability or desire to pursue if granted the opportunity to do so, and no such person shall be liable to us for breach of any fiduciary or other duty, as a director or officer or controlling stockholder or otherwise, by reason of the fact that such person pursues or acquires any such business opportunity, directs any such business opportunity to another person or fails to present any such business opportunity, or information regarding any such business opportunity, to us unless, in the case of any such person who is our director or officer, any such business opportunity is expressly offered to such director or officer solely in his or her capacity as our director or officer.

The transfer agent and registrar for our common stock is Computershare Trust Company, N.A.

We may issue warrants for the purchase of our common stock. Warrants may be issued independently or together with Debt Securities, preferred stock or common stock offered by any prospectus supplement and may be attached to or separate from any such offered securities. Each series of warrants will be issued under a separate warrant agreement to be entered into between us and a bank or trust company, as warrant agent, all as set forth in the prospectus supplement relating to the particular issue of warrants. The warrant agent will act solely as our agent in connection with the warrants and will not assume any obligation or relationship of agency or trust for or with any holders of warrants or beneficial owners of warrants. The following summary of certain provisions of the warrants does not purport to be complete and is subject to, and is qualified in its entirety by reference to, all provisions of the warrant agreements.

You should refer to the prospectus supplement relating to a particular issue of warrants for the terms of and information relating to the warrants, including, where applicable:

(1) the number of shares of common stock purchasable upon exercise of the warrants and the price at which such number of shares of common stock may be purchased upon exercise of the warrants;

(2) the date on which the right to exercise the warrants commences and the date on which such right expires (the “Expiration Date”);

(4) the amount of the warrants outstanding as of the most recent practicable date; and

Warrants will be offered and exercisable for United States dollars only. Warrants will be issued in registered form only. Each warrant will entitle its holder to purchase such number of shares of common stock at such exercise price as is in each case set forth in, or calculable from, the prospectus supplement relating to the warrants. The exercise price may be subject to adjustment upon the occurrence of events described in such prospectus supplement. After the close of business on the Expiration Date (or such later date to which we may extend such Expiration Date), unexercised warrants will become void. The place or places where, and the manner in which, warrants may be exercised will be specified in the prospectus supplement relating to such warrants.

Prior to the exercise of any warrants, holders of the warrants will not have any of the rights of holders of common stock, including the right to receive payments of any dividends on the common stock purchasable upon exercise of the warrants, or to exercise any applicable right to vote.

We may sell the offered securities in and outside the United States (1) through underwriters or dealers, (2) directly to purchasers, including our affiliates and stockholders, (3) through agents or (4) through a combination of any of these methods. The prospectus supplement will include the following information:

If underwriters are used in the sale, the underwriters will acquire the securities for their own account for resale to the public, either on a firm commitment basis or a best efforts basis. The underwriters may resell the securities from time to time in one or more transactions, including negotiated transactions, at a fixed public offering price or at varying prices determined at the time of sale. Underwriters may offer securities to the public either through underwriting syndicates represented by one or more managing underwriters or directly by one or more firms acting as underwriters. Unless we inform you otherwise in the prospectus supplement, the obligations of the underwriters to purchase the securities will be subject to certain conditions. The underwriters may change from time to time any offering price and any discounts or concessions allowed or reallowed or paid to dealers.

During and after an offering through underwriters, the underwriters may purchase and sell the securities in the open market. These transactions may include overallotment and stabilizing transactions and purchases to cover syndicate short positions created in connection with the offering. The underwriters may also impose a penalty bid, which means that selling concessions allowed to syndicate members or other broker-dealers for the offered securities sold for their account may be reclaimed by the syndicate if the offered securities are repurchased by the syndicate in stabilizing or covering transactions. These activities may stabilize, maintain or otherwise affect the market price of the offered securities, which may be higher than the price that might otherwise prevail in the open market. If commenced, the underwriters may discontinue these activities at any time.

If dealers are used, we will sell the securities to them as principals. The dealers may then resell that securities to the public at varying prices determined by the dealers at the time of resale. We will include in the prospectus supplement the names of the dealers and the terms of the transaction.

We may sell the securities directly. In this case, no underwriters or agents would be involved. We may also sell the securities through agents designated from time to time. In the prospectus supplement, we will name any agent involved in the offer or sale of the offered securities, and we will describe any commissions payable to the agent. Unless we inform you otherwise in the prospectus supplement, any agent will agree to use its reasonable best efforts to solicit purchases for the period of its appointment.

We may sell the securities directly to institutional investors or others who may be deemed to be underwriters within the meaning of the Securities Act with respect to any sale of securities. We will describe the terms of any such sales in the prospectus supplement.

Offered securities may also be offered and sold, if so indicated in the applicable prospectus supplement, in connection with a remarketing upon their purchase, in accordance with a redemption or repayment pursuant to their terms, or otherwise, by one or more remarketing firms, acting as principals for their own accounts or as agents for us. Any remarketing firm will be identified and the terms of its agreements, if any, with us and its compensation will be described in the applicable prospectus supplement. Remarketing firms may be deemed to be underwriters, as that term is defined in the Securities Act, in connection with the securities remarketed.

If we so indicate in the prospectus supplement, we may authorize agents, underwriters or dealers to solicit offers from certain types of institutions to purchase securities from us at the public offering price under delayed delivery contracts. These contracts would provide for payment and delivery on a specified date in the future. The contracts would be subject only to those conditions described in the prospectus supplement. The prospectus supplement will describe the commission payable for solicitation of those contracts.

We may have agreements with the agents, dealers, underwriters and remarketing firms to indemnify them against certain civil liabilities, including liabilities under the Securities Act, or to contribute with respect to payments that the agents, dealers, underwriters or remarketing firms may be required to make. Agents, dealers, underwriters and remarketing firms may be customers of, engage in transactions with, or perform services for us in the ordinary course of their businesses.

Certain legal matters in connection with the securities will be passed upon by Vinson & Elkins L.L.P, Houston, Texas, as our counsel. Any underwriter or agent will be advised about other issues relating to any offering by its own legal counsel.

The consolidated financial statements of Oasis Petroleum Inc. and subsidiaries incorporated in this prospectus by reference to the Current Report on Form 8-K dated July 15, 2011 for the year ended December 31, 2010 have been so incorporated in reliance on the report of PricewaterhouseCoopers LLP, an independent registered public accounting firm, given on the authority of said firm as experts in auditing and accounting.

Certain estimates of our net crude oil and natural gas reserves and related information included or incorporated by reference in this prospectus have been derived from reports prepared by W.D. Von Gonten & Co. and DeGolyer and MacNaughton. All such information has been so included or incorporated by reference on the authority of such firms as experts regarding the matters contained in their reports.



Title of Each Class of Securities Offered	Amount to be Registered	Proposed Maximum Aggregate Offering Price Per Share(1)	Proposed Maximum Aggregate Offering Price(1)	Amount of Registration Fee(2)
Common Stock	7,000,000	$45.57	$318,990,000	$41,085.91


About This Prospectus Supplement			S-ii
Where You Can Find More Information			S-ii
Cautionary Statement Regarding Forward-Looking Statements			S-iii
Summary			S-1
Risk Factors			S-4
Use of Proceeds			S-6
Capitalization			S-7
Price Range of Common Stock			S-8
Dividend Policy			S-8
Material U.S. Federal Income Tax Consequences to Non-U.S. Holders			S-9
Underwriting (Conflicts of Interest)			S-13
Legal Matters			S-17
Experts			S-17


About this Prospectus			1
The Company			1
Where You Can Find More Information			2
Cautionary Note Regarding Forward-Looking Statements			3
Risk Factors			5
Ratios of Earnings to Fixed Charges			5
Use of Proceeds			5
Description of Debt Securities			6
Description of Capital Stock			18
Description of Warrants			22
Plan of Distribution			23
Legal Matters			25
Experts			25


	As of September 30, 2013
	Actual			As Adjusted			As Further Adjusted
	(In thousands)
Cash and Cash Equivalents (1)	$	125,440		$	145,550		$	195,550

Restricted Cash (2)	$	986,210		$	—		$	—

Long-term Debt:
Revolving credit facility(3)(4)(5)		160,000			600,000			335,570
7.25% Senior Notes due 2019		400,000			400,000			400,000
6.5% Senior Notes due 2021		400,000			400,000			400,000
6.875% Senior Notes due 2023		400,000			400,000			400,000
6.875% Senior Notes due 2022		1,000,000			1,000,000			1,000,000

Total long-term debt		2,360,000			2,800,000			2,535,570

Stockholders’ Equity:
Common stock, $0.01 par value; 300,000,000 shares authorized; (i) 93,854,867 issued and 93,690,494 outstanding (actual), (ii) 93,854,867 issued and 93,690,494 outstanding (as adjusted), (iii) 100,854,867 issued and 100,690,494 outstanding (as further adjusted)		926			926			996
Treasury stock, at cost, 164,373 shares		(5,220	)		(5,220	)		(5,220	)
Additional paid-in-capital		666,770			666,770			981,130
Retained earnings		313,402			313,402			313,402

Total stockholders’ equity		975,878			975,878			1,290,308

Total Capitalization	$	3,335,878		$	3,775,878		$	3,825,878


	Sales Price
	High		Low
2011:
First quarter	$	36.15	$	25.76
Second quarter	$	33.59	$	25.54
Third quarter	$	32.93	$	20.27
Fourth quarter	$	33.65	$	17.99
2012:
First quarter	$	35.46	$	28.34
Second quarter	$	33.90	$	22.02
Third quarter	$	32.72	$	23.28
Fourth quarter	$	32.26	$	28.15
2013:
First quarter	$	39.78	$	31.45
Second quarter	$	42.89	$	31.58
Third quarter	$	49.48	$	37.86
Fourth quarter (through December 2, 2013)	$	57.33	$	44.50


ABOUT THIS PROSPECTUS			1
THE COMPANY			1
WHERE YOU CAN FIND MORE INFORMATION			2
CAUTIONARY NOTE REGARDING FORWARD-LOOKING STATEMENTS			3
RISK FACTORS			5
RATIO OF EARNINGS TO FIXED CHARGES			5
USE OF PROCEEDS			5
DESCRIPTION OF DEBT SECURITIES			6
DESCRIPTION OF CAPITAL STOCK			18
DESCRIPTION OF WARRANTS			22
PLAN OF DISTRIBUTION			23
LEGAL MATTERS			25
EXPERTS			25