**UNITED STATES**

**SECURITIES AND EXCHANGE COMMISSION**

**Washington, D.C. 20549**

 

**FORM 10-K/A**

 
| **x** | ** ** | **ANNUAL   REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE   ACT OF 1934** |
|-------|------------|-------------------------------------------------------------------------------------------------------------|

** **

**For the Fiscal Year Ended December 31, 2010**

 

**OR**

** **
| **o** | ** ** | **TRANSITION   REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE   ACT OF 1934** |
|-------|------------|-----------------------------------------------------------------------------------------------------------------|

 

**COMMISSION FILE NUMBER 000-33275**

 

**Warren Resources, Inc.**

(Exact name of registrant as specified in its charter)

 

| **Maryland**   (State or other jurisdiction of   incorporation or organization)       | ** ** | **11-3024080**   (I.R.S. Employer   Identification No.) |
|---------------------------------------------------------------------------------------|------------|---------------------------------------------------------|
| ** **                                                                            | ** ** | ** **                                              |
| **1114 Ave of the Americas, New York, NY**   (Address of principal executive offices) | ** ** | **10036**   (Zip Code)                                  |

 

Registrant’s telephone number, including area code: **(212) 697-9660**

 

Securities registered pursuant to Section 12(b) of the Act: **None**

 

Securities registered pursuant to Section 12(g) of the Act:

 

**Common Stock, $.0001 par value per share**

(Title of Class)

 

Indicate by check mark if the registrant is a well-known seasoned issuer, as defined in Rule 405 of the Securities Act.  o Yes  x No

 

Indicate by check mark if the registrant is not required to file reports pursuant to Section 13 or Section 15(d) of the Act.  o Yes  x No

 

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

 

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

 

Indicate by check mark if disclosure of delinquent filers pursuant to Item 405 of Regulation S-K is not contained herein, and will not be contained, to the best of registrant’s knowledge, in definitive proxy or information statements incorporated by reference in Part III of this Form 10-K or any amendment to this Form 10-K.  o

 

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

 

| Large accelerated filer o                  |   | Accelerated filer x         |
|-------------------------------------------------|--------|----------------------------------|
|                                            |   |                             |
| Non-accelerated filer o                    |   | Smaller reporting company o |
| (Do not check if a   smaller reporting company) |   |                             |

 

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

 

The aggregate market value of the registrant’s common stock held by non-affiliates of the registrant on June 30, 2010 was $198,838,631.

 

The number of shares of registrant’s common stock outstanding as of March 1, 2011 was 71,348,149 shares.

 

**DOCUMENTS INCORPORATED BY REFERENCE:**

 

Certain portions of the registrant’s definitive proxy statement to be filed with the Securities and Exchange Commission pursuant to Regulation 14A not later than April 30, 2011, in connection with the registrant’s 2011 Annual Meeting of Stockholders, are incorporated herein by reference into Part III of this Annual Report on Form 10-K.

 

 

 

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**EXPLANATORY NOTE**

 

Warren Resources, Inc. (“Warren” or the “Company”)  is filing this Amendment No. 1 to our Form 10-K for the year ended December 31, 2010, solely for the purpose of filing a revised report from our third-party petroleum engineering firm. The report from Williamson Petroleum Consultants, Inc. was filed as Exhibit 99.1 to the 2010 Form 10-K, which originally was filed with the Securities and Exchange Commission on March 2, 2011. In addition to the revised engineering report being filed as Exhibit 99.1, we are including in this Form 10-K/A a consent from Williamson Petroleum Consultants, Inc. in Exhibit 23.1 and certifications of our principal executive officer and principal financial officer in Exhibit 31.1 and 31.2.

 

No item of or disclosures appearing in our originally filed 2010 Form 10-K are affected by this filing other than the exhibits described above. This report on Form 10-K/A is presented as of the filing date of the originally filed 2010 Form 10-K and does not reflect events occurring after that date, or modify or update disclosures in any way.

 

**PART IV**

 

**Item 15. *Exhibits, Financial Statement Schedules***

 

**(a) (3) Exhibits**

 
| **Exhibit********Number** | ** ** | **Description**                                                                    |
|---------------------------|------------|------------------------------------------------------------------------------------|
| ** **                | ** ** | ** **                                                                         |
| 23.1*                     |       | Consent   of Williamson Petroleum Consultants, Inc.                           |
|                      |       |                                                                               |
| 31.1*                     |       | Rule 13(a)-14(a)/15d-14(a) Certificate   of the Chief Executive Officer. |
|                      |       |                                                                               |
| 31.2*                     |       | Rule 13(a)-14(a)/15d-14(a) Certificate   of the Chief Financial Officer. |
|                      |       |                                                                               |
| 99.1*                     |       | Report   of Williamson Petroleum Consultants, Inc.                            |

 

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*  Filed herewith. 

 

**SIGNATURES**

 

Pursuant to the requirements of Section 13 or 15(d) of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.

 
|                   | WARREN   RESOURCES, INC.                                                                             |
|------------------------|-----------------------------------------------------------------------------------------------------------|
|                   |                                                                                                      |
| Date: October 27, 2011 | /s/   Timothy A. Larkin                                                                                   |
|                   | Timothy   A. Larkin, Executive Vice President and Chief Financial Officer (Principal   Financial Officer) |

 

**EXHIBIT INDEX**

 
| **Exhibit********Number** | ** ** | **Description**                                                                    |
|---------------------------|------------|------------------------------------------------------------------------------------|
| ** **                | ** ** | ** **                                                                         |
| 23.1*                     |       | Consent   of Williamson Petroleum Consultants, Inc.                           |
|                      |       |                                                                               |
| 31.1*                     |       | Rule 13(a)-14(a)/15d-14(a) Certificate   of the Chief Executive Officer. |
|                      |       |                                                                               |
| 31.2*                     |       | Rule 13(a)-14(a)/15d-14(a) Certificate   of the Chief Financial Officer. |
|                      |       |                                                                               |
| 99.1*                     |       | Report   of Williamson Petroleum Consultants, Inc.                            |

 

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*  Filed herewith. 

 

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