Ownership Submission
FORM 4
Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).
UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN 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
OMB APPROVAL
OMB Number: 3235-0287
Expires: January 31, 2005
Estimated average burden hours per response... 0.5

(Print or Type Responses)
1. Name and Address of Reporting Person *
ENCAP ENERGY CAPITAL FUND VI L P
  2. Issuer Name and Ticker or Trading Symbol
Oasis Petroleum Inc. [OAS]
5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
_____ Director __X__ 10% Owner
_____ Officer (give title below) _____ Other (specify below)
(Last)
(First)
(Middle)
1100 LOUISIANA, SUITE 4900
3. Date of Earliest Transaction (Month/Day/Year)
01/31/2012
(Street)

HOUSTON, TX 77002
4. If Amendment, Date Original Filed(Month/Day/Year)
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 Acquired, Disposed of, or Beneficially Owned
1.Title of Security
(Instr. 3)
2. Transaction Date (Month/Day/Year) 2A. Deemed Execution Date, if any (Month/Day/Year) 3. Transaction Code
(Instr. 8)
4. Securities Acquired (A) or Disposed of (D)
(Instr. 3, 4 and 5)
5. Amount of Securities Beneficially Owned Following Reported Transaction(s)
(Instr. 3 and 4)
6. Ownership Form: Direct (D) or Indirect (I)
(Instr. 4)
7. Nature of Indirect Beneficial Ownership
(Instr. 4)
Code V Amount (A) or (D) Price
Common Stock 01/31/2012   S   7,000,000 (1) D $ 32 7,284,753 D (1) (2) (3) (4) (5)  

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB control number. SEC 1474 (9-02)

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned
(e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security
(Instr. 3)
2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (Month/Day/Year) 3A. Deemed Execution Date, if any (Month/Day/Year) 4. Transaction Code
(Instr. 8)
5. Number of Derivative Securities Acquired (A) or Disposed of (D)
(Instr. 3, 4, and 5)
6. Date Exercisable and Expiration Date
(Month/Day/Year)
7. Title and Amount of Underlying Securities
(Instr. 3 and 4)
8. Price of Derivative Security
(Instr. 5)
9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s)
(Instr. 4)
10. Ownership Form of Derivative Security: Direct (D) or Indirect (I)
(Instr. 4)
11. Nature of Indirect Beneficial Ownership
(Instr. 4)
Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares

Reporting Owners

Reporting Owner Name / Address Relationships
 Director  10% Owner  Officer  Other
ENCAP ENERGY CAPITAL FUND VI L P
1100 LOUISIANA, SUITE 4900
HOUSTON, TX 77002
    X    
EnCap VI-B Acquisitions, L.P.
1100 LOUISIANA, SUITE 4900
HOUSTON, TX 77002
    X    
ENCAP ENERGY CAPITAL FUND VII LP
1100 LOUISIANA, SUITE 4900
HOUSTON, TX 77002
    X    
MILLER DAVID B
1100 LOUISIANA, SUITE 4900
HOUSTON, TX 77002
    X    
PHILLIPS D MARTIN
1100 LOUISIANA, SUITE 4900
HOUSTON, TX 77002
    X    
PETERSEN GARY R
1100 LOUISIANA, SUITE 4900
HOUSTON, TX 77002
    X    

Signatures

 /s/ EnCap Energy Capital Fund VI, L.P., By EnCap Equity Fund VI GP, L.P., its GP, By EnCap Investments, L.P., its GP, By EnCap Investments GP, L.L.C., its GP, By /s/ Robert L. Zorich, Sr. Mg. Dr.   02/02/2012
**Signature of Reporting Person Date

 /s/ EnCap VI-B Acq, LP, By EnCap VI-B Acq GP, LLC, its GP By EnCap Energy Capital Fund VI-B, LP its sole member, By EnCap Equity Fund VI GP, LP its GP, By EnCap Invest. LP its GP, By EnCap Invest. GP LLC, its GP, By /s/ Robert L. Zorich, Sr. Mg. Dr.   02/02/2012
**Signature of Reporting Person Date

 /s/ EnCap Energy Capital Fund VII, L.P., By EnCap Equity Fund VI GP, L.P., its GP, By EnCap Investments, L.P., its GP, By EnCap Investments GP, L.L.C., its GP, By /s/ Robert L. Zorich, Sr. Mg. Dr.   02/02/2012
**Signature of Reporting Person Date

 /s/ David B. Miller   02/02/2012
**Signature of Reporting Person Date

 /s/ D. Martin Phillips   02/02/2012
**Signature of Reporting Person Date

 /s/ Gary R. Petersen   02/02/2012
**Signature of Reporting Person Date

Explanation of Responses:

* If the form is filed by more than one reporting person, see Instruction 4(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) On January 31, 2012, EnCap Energy Capital Fund VI, L.P. ("EnCap Fund VI"), EnCap VI-B Acquisitions, L.P. ("EnCap VI-B") and EnCap Energy Capital Fund VII, L.P. ("EnCap Fund VII" and, together with EnCap Fund VI and EnCap VI-B, the "EnCap Funds") collectively sold 7,000,000 shares of common stock of Oasis Petroleum Inc. in a block trade. EnCap Fund VI sold 2,965,277 shares, EnCap VI-B sold 1,623,138 shares and EnCap Fund VII sold 2,411,585 shares.
(2) The EnCap Funds are controlled indirectly by David B. Miller, D. Martin Phillips, Gary R. Petersen, and Robert L. Zorich (the "Managing Directors"). The Managing Directors are members of RNBD GP LLC ("RNBD") and any action taken by RNBD to dispose or acquire securities has to be unanimously approved by all four members. RNBD is the sole member of EnCap Investments GP, L.L.C. ("EnCap Investments GP"), which is the general partner of EnCap Investments L.P. ("EnCap Investments LP"), which is the general partner of EnCap Equity Fund VI GP, L.P. ("EnCap Fund VI GP") and EnCap Equity Fund VII GP, L.P. ("EnCap Fund VII GP").
(3) EnCap Fund VI GP is the sole general partner of EnCap Fund VI and EnCap Fund VII GP is the sole general partner of EnCap Fund VII. EnCap Fund VI GP is also the general partner of EnCap Energy Capital Fund VI-B ("EnCap Fund VI-B"), which is the sole member of EnCap VI-B Acquisitions GP, LLC ("EnCap VI-B GP"), which is the sole general partner of EnCap VI-B. Therefore, the Managing Directors, RNBD, EnCap Investments GP, EnCap Investments LP, EnCap Fund VI GP, EnCap Fund VII GP, EnCap Fund VI-B, and EnCap VI-B GP may be deemed to beneficially own the reported securities.
(4) This report is filed in connection with the Form 4 filed today by Mr. Zorich, a director of the issuer.
(5) The reporting persons disclaim beneficial ownership of the reported securities except to the extent of their pecuniary interest therein, and this report shall not be deemed an admission that the reporting persons are the beneficial owners of the reported securities for purposes of Section 16 or for any other purpose.

Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.

Potential persons who are to respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB number.