FORM 3

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 INITIAL STATEMENT OF BENEFICIAL OWNERSHIP OF SECURITIES Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

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(Print or Type Responses)

1. Name and Address of Reporting Person *   SPO ADVISORY CORP 2. Date of Event Requiring Statement (Month/Day/Year) 08/24/2011 3. Issuer Name and Ticker or Trading Symbol Oasis Petroleum Inc. [OAS] (Last) (First) (Middle) 591 REDWOOD HIGHWAY, SUITE 3215 4. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director __X__ 10% Owner _____ Officer (give title below) _____ Other (specify below) 5. If Amendment, Date Original Filed(Month/Day/Year) (Street) MILL VALLEY, CA 94941 6. Individual or Joint/Group Filing(Check Applicable Line) ___ Form filed by One Reporting Person _X_ Form filed by More than One Reporting Person (City) (State) (Zip) Table I - Non-Derivative Securities Beneficially Owned

1.Title of Security (Instr. 4) 2. Amount of Securities Beneficially Owned (Instr. 4) 3. Ownership Form: Direct (D) or Indirect (I) (Instr. 5) 4. Nature of Indirect Beneficial Ownership (Instr. 5) Common Stock 9,275,809 I (1) (2) See Footnotes

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.			SEC 1473 (7-02)
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Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)

1. Title of Derivative Security (Instr. 4)	2. Date Exercisable and Expiration Date (Month/Day/Year)		3. Title and Amount of Securities Underlying Derivative Security (Instr. 4)		4. Conversion or Exercise Price of Derivative Security	5. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 5)	6. Nature of Indirect Beneficial Ownership (Instr. 5)
	Date Exercisable	Expiration Date	Title	Amount or Number of Shares

Reporting Owners

Reporting Owner Name / Address	Relationships
	Director	10% Owner	Officer	Other
SPO ADVISORY CORP 591 REDWOOD HIGHWAY, SUITE 3215 MILL VALLEY, CA 94941	Â	  X	Â	Â
SPO ADVISORY PARTNERS LP 591 REDWOOD HIGHWAY, SUITE 3215 MILL VALLEY, CA 94941	Â	  X	Â	Â
SF ADVISORY PARTNERS LP 591 REDWOOD HIGHWAY , SUITE 3215 MILL VALLEY, CA 94941	Â	  X	Â	Â
SPO PARTNERS II LP 591 REDWOOD HIGHWAY, SUITE 3215 MILL VALLEY, CA 94941	Â	  X	Â	Â
SAN FRANCISCO PARTNERS LP 591 REDWOOD HIGHWAY, SUITE 3215 MILL VALLEY, CA 94941	Â	  X	Â	Â
SCULLY JOHN H 591 REDWOOD HIGHWAY, SUITE 3215 MILL VALLEY, CA 94941	Â	  X	Â	Â
OBERNDORF WILLIAM E 591 REDWOOD HIGHWAY, SUITE 3215 MILL VALLEY, CA 94941	Â	  X	Â	Â
MCDERMOTT EDWARD H 591 REDWOOD HIGHWAY , SUITE 3215 MILL VALLEY, CA 94941	Â	  X	Â	Â

Signatures

Kim M. Silva, Attorney-in-Fact		08/29/2011
**Signature of Reporting Person		Date

Explanation of Responses:

*	If the form is filed by more than one reporting person, see Instruction 5(b)(v).
**	Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
(1)	As a result of the purchases causing this filing, 8,975,909 shares of the Issuer's common stock are directly owned by SPO Partners II, L.P. ("SPO Partners"), and may be deemed to be indirectly beneficially owned by (i) SPO Advisory Partners, L.P. ("SPO Advisory"), the sole general partner of SPO Partners, (ii) SPO Advisory Corp. ("SPO Corp."), the sole general partner of SPO Advisory, and (iii) John H. Scully ("JHS"), William E. Oberndorf ("WEO") and Edward H. McDermott ("EHM"), the three controlling persons of SPO Corp. 299,900 shares of the Issuer's common stock are directly owned by San Francisco Partners, L.P. ("SF Partners"), and may be deemed to be indirectly beneficially owned by (i) SF Advisory Partners, L.P. ("SF Advisory"), the sole general partner of SF Partners, (ii) SPO Corp., the sole general partner of SF Advisory, and (iii) JHS, WEO & EHM, the three controlling persons of SPO Corp.
(2)	Additionally, (i) JHS owns 14,600 shares of the Issuer's common stock in his IRAs, which are self-directed, (ii) WEO owns 48,700 shares of the Issuer's common stock in his IRA, which is self-directed, and (iii) EHM owns 1,000 shares of the Issuer's common stock in his IRAs, which are self directed.
  Remarks: The individuals and entities listed in the notes above (each a "Reporting Person") may be deemed to form a "group", as such term is defined in rule 13d-5(b)(1) promulgated under the Securities Exchange Act of 1934, for purposes of this filing. This filing shall not be deemed as an admission by any Reporting Person that such Person is, for purposes of Section 16 of the Securities Exchange Act of 1934 or otherwise, the beneficial owner of any equity securities covered by this statement. Each Reporting Person disclaims beneficial ownership of the reported securities except to the extent of such person's pecuniary interest, if any, therein.

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