UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549





FORM 40-F





(Check One)

| ̈ | Registration statement pursuant to Section 12 of the Securities Exchange Act of 1934
|- | ------------------------------------------------------------------------------------

or



|x | Annual report pursuant to section 13(a) or 15(d) of the Securities Exchange Act of 1934
|- | ---------------------------------------------------------------------------------------

For the fiscal year ended December 31, 2012

Commission file number 1-32895





PENN WEST
PETROLEUM LTD.

(Exact name of registrant as specified in its charter)







|                                                                  |  |                                                                          |  |                                                        
|----------------------------------------------------------------- |  | ------------------------------------------------------------------------ |  | -------------------------------------------------------
|Alberta, Canada                                                   |  | 1311                                                                     |  | Not applicable                                         
|(Province or other jurisdiction of
incorporation or organization) |  | (Primary Standard Industrial Classification Code Number (if applicable)) |  | (I.R.S. Employer Identification Number (if Applicable))

Suite 200, 207  9thAvenue SW, Calgary, Alberta, Canada T2P 1K3

(403) 777-2500

(Address and Telephone Number of Registrants Principal Executive Offices)

DL Services Inc., Columbia Center, 701 Fifth Avenue, Suite 6100, Seattle, Washington 98104-7043

(206) 903-5448

(Name, Address (Including Zip Code) and Telephone Number

(Including Area Code) of Agent For Service in the United States)

Securities registered or to be registered pursuant to Section 12(b) of the Act.



|                    |  |                                          
|------------------- |  | -----------------------------------------
|Title of each class |  | Name of each exchange on which registered
|Common Shares       |  | New York Stock Exchange                  

Securities registered or to be registered pursuant to Section 12(g) of the Act: None

Securities for which there is a reporting obligation pursuant to Section 15(d) of the Act: None

For annual reports, indicate by check mark the information filed with this Form:



|                         |  |                                     
|------------------------ |  | ------------------------------------
|xAnnual Information Form |  | xAudited Annual Financial Statements





Indicate the number of outstanding shares of each of the issuers classes of capital or common stock as of the close of the period
covered by the annual report:479,258,670

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

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









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FORM 40-F

Principal Documents

The following documents, filed as Exhibits 99.1, 99.2, 99.3 and 99.4
to this Annual Report on Form 40-F, are hereby incorporated by reference into this Annual Report on Form 40-F:



| | (a) | Annual Information Form for the fiscal year ended December 31, 2012;
| | --- | --------------------------------------------------------------------



| | (b) | Managements Discussion and Analysis of Financial Condition and Results of Operations for the fiscal year ended December 31, 2012; and
| | --- | --------------------------------------------------------------------------------------------------------------------------------------



| | (c) | Audited Consolidated Financial Statements for the fiscal year ended December 31, 2012, prepared under International Financial Reporting Standards as issued by the
International Accounting Standards Board.
| | --- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------



| | (d) | Supplemental Oil and Gas information
| | --- | ------------------------------------



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ADDITIONAL DISCLOSURE

Certifications and Disclosure Regarding Controls and Procedures.



|(a) | Certifications. See Exhibits 99.5, 99.6, 99.7 and 99.8 to this Annual Report on Form 40-F.
|--- | ------------------------------------------------------------------------------------------



|(b) | Disclosure Controls and Procedures. As of the end of Penn West Petroleum Ltd.s (Penn West) fiscal year ended December 31, 2012, an
evaluation of the effectiveness of Penn Wests disclosure controls and procedures (as such term is defined in Rules 13a-15(e) and 15d-15(e) under the Exchange Act) was carried out by the management of Penn West, with the
participation of the President & Chief Executive Officer (CEO) and the Executive Vice President and Chief Financial Officer (CFO) of Penn West. Based upon that evaluation, the CEO and CFO have concluded that as of
the end of that fiscal year, Penn Wests disclosure controls and procedures were effective to ensure that information required to be disclosed by Penn West in reports that it files or submits under the Exchange Act is (i) recorded,
processed, summarized and reported within the time periods specified in Securities and Exchange Commission (the Commission) rules and forms and (ii) accumulated and communicated to the management of Penn West, including the CEO and
CFO, to allow timely decisions regarding required disclosure.
|--- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

It should be noted that while the CEO and CFO
believe that Penn Wests disclosure controls and procedures provide a reasonable level of assurance that they are effective, they do not expect that Penn Wests disclosure controls and procedures or internal control over financial
reporting will prevent all errors and fraud. A control system, no matter how well conceived or operated, can provide only reasonable, not absolute, assurance that the objectives of the control system are met.



|(c) | Managements Annual Report on Internal Control Over Financial Reporting.
|--- | ------------------------------------------------------------------------

Management is responsible for establishing and maintaining adequate internal control over Penn Wests financial reporting. Penn
Wests internal control system was designed to provide reasonable assurance that all transactions are accurately recorded, that transactions are recorded as necessary to permit preparation of financial statements in accordance with generally
accepted accounting principles, and that Penn Wests assets are safeguarded.

Management has assessed the effectiveness of
Penn Wests internal control over financial reporting as at December 31, 2012. In making its assessment, management used the Committee of Sponsoring Organizations of the Treadway Commission (COSO) framework in Internal Control
 Integrated Framework to evaluate the effectiveness of Penn Wests internal control over financial reporting. Based on this assessment, management has concluded that Penn Wests internal control over financial reporting was effective
as of December 31, 2012.



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The effectiveness of Penn Wests internal control over financial reporting as at
December 31, 2012 has been audited by KPMG LLP, as stated in their Report of Independent Registered Public Accounting Firm on Penn Wests internal control over financial reporting that accompanies Penn Wests Audited Consolidated
Financial Statements for the fiscal year ended December 31, 2012, filed as Exhibit 99.3 to this Annual Report on Form 40-F.



|(d) | Attestation Report of the Registered Public Accounting Firm. The required disclosure is included in the Report of Independent Registered Public Accounting Firm
on Penn Wests internal control over financial reporting that accompanies Penn Wests Audited Consolidated Financial Statements for the fiscal year ended December 31, 2012, filed as Exhibit 99.3 to this Annual Report on Form 40-F.
|--- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------



|(e) | Changes in Internal Control Over Financial Reporting. There were no changes in Penn Wests internal control over financial reporting that occurred during
the fiscal year ended December 31, 2012 that have materially affected, or are reasonably likely to materially affect, Penn Wests internal control over financial reporting.
|--- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

Notices Pursuant to Regulation BTR.

None.

Audit Committee Financial Expert.

Penn Wests board of directors has determined that James C. Smith, a member of Penn Wests audit committee, qualifies as an
audit committee financial expert (as such term is defined in Form 40-F). Mr. Smith is independent as that term is defined in the rules of the New York Stock Exchange.

Code of Business Conduct.

Penn
West has adopted a Code of Ethics for Officers and Senior Financial Management. Penn West has also adopted a Code of Business Conduct and Ethics that applies to all employees, officers and directors of Penn West. Together, these Codes constitute a
code of ethics as defined in Form 40-F and are collectively referred to in this Annual Report on Form 40-F as the Code of Ethics.

The Code of Ethics, including each of its components, is available for viewing on Penn Wests website at www.pennwest.com, and is available in print to any shareholder who requests a copy. Requests
for copies of the Code of Ethics or any portion of it should be made by contacting: investor relations by phone at (888) 770-2633 or by e-mail to investor_relations@pennwest.com.



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Since the adoption of each component of the Code of Ethics, there have not been any amendments to, or
waivers, including implicit waivers, from, any provision of such Codes.

If any amendment to the Code of Ethics is made, or if any waiver from
the provisions thereof is granted, Penn West may elect to disclose the information about such amendment or waiver required by Form 40-F to be disclosed, by posting such disclosure on Penn Wests website, which may be accessed at
www.pennwest.com.

Principal Accountant Fees and Services.

The following table sets forth information about the fees billed to Penn West for professional services provided by KPMG LLP during fiscal 2012 and 2011:



|                   |  |      |           |  |      |  |           | 
|------------------ |  | ---- | --------- |  | ---- |  | --------- | 
|(CDN$)             |  | 2012 |           |  | 2011 | 
|Audit Fees         |  |      | 1,120,000 |  |      |  | 1,230,000 | 
|Audit-Related Fees |  |      | 146,000   |  |      |  | 157,500   | 
|Tax Fees           |  |      | 38,000    |  |      |  |          | 
|                   |  |      |           |  |      |  |           | 
|Total              |  |      | 1,304,000 |  |      |  | 1,387,500 | 
|                   |  |      |           |  |      |  |           | 

Audit Fees. Audit fees consist of fees for the integrated audit of Penn Wests annual financial
statements or services that are normally provided in connection with statutory and regulatory filings or engagements, reviews in connection with acquisitions and Sarbanes-Oxley Act related services, long-form comfort letters related to the public
offering of securities and review procedures on the unaudited interim consolidated financial statements.

Audit-Related Fees.
Audit-related fees primarily consist of assurance and related services for the Peace River Oil Partnership audit and for French translation services.

Tax fees. Tax fees consist of professional services for tax compliance, tax advice and tax planning.



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Pre-Approval Policies and Procedures.



|(a) | The terms of the engagement of Penn Wests external auditors to provide audit services, including the budgeted fees for such audit services and the representations
and disclaimers relating thereto, must be pre-approved by the entire audit committee.
|--- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

With respect to any
engagements of Penn Wests external auditors for non-audit services, Penn West must obtain the approval of the audit committee or the Chairman of the audit committee prior to retaining the external auditors to complete such engagement. If such
pre-approval is provided by the Chairman of the audit committee, the Chairman shall report to the audit committee on any non-audit service engagement pre-approved by him at the audit committees first scheduled meeting following such
pre-approval.

If, after using its reasonable best efforts, Penn West is unable to contact the Chairman of the audit committee
on a timely basis to obtain the pre-approval contemplated by the preceding paragraph, Penn West may obtain the required pre-approval from any other member of the audit committee, provided that any such audit committee member shall report to the
audit committee on any non-audit service engagement pre-approved by him at the audit committees first scheduled meeting following such pre-approval.



|(b) | Of the fees reported in this Annual Report on Form 40-F under the heading Principal Accountant Fees and Services, none of the fees billed by KPMG LLP were
approved by Penn Wests audit committee pursuant to the de minimus exception provided by Section (c)(7)(i)(C) of Rule 2-01 of Regulation S-X.
|--- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

Off-Balance Sheet Arrangements.

Penn West has off-balance-sheet financing arrangements
consisting of operating leases. The operating lease payments are summarized below in the Tabular Disclosure of Contractual Obligations.



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Tabular Disclosure of Contractual Obligations.



|                              |  |       |       |  |                       |  |     |             |  |  |             |  |  |                 |       |  |  |  |       | 
|----------------------------- |  | ----- | ----- |  | --------------------- |  | --- | ----------- |  |  | ----------- |  |  | --------------- | ----- |  |  |  | ----- | 
|(CDN$ millions)               |  |       |       |  | Payment due by period | 
|Contractual Obligations       |  | Total |       |  | Less than1 Year       |  |     | 1 to 3Years |  |  | 3 to 5Years |  |  | Morethan 5Years |      
|Transportation                |  |       | 56    |  |                       |  | 24  |             |  |  | 27          |  |  |                 | 5     |  |  |  |      | 
|Transportation ($US)          |  |       | 342   |  |                       |  | 4   |             |  |  | 74          |  |  |                 | 66    |  |  |  | 198   | 
|Power infrastructure          |  |       | 97    |  |                       |  | 29  |             |  |  | 28          |  |  |                 | 28    |  |  |  | 12    | 
|Drilling rigs                 |  |       | 78    |  |                       |  | 23  |             |  |  | 38          |  |  |                 | 17    |  |  |  |      | 
|Purchase obligations (1)      |  |       | 19    |  |                       |  | 6   |             |  |  | 10          |  |  |                 | 2     |  |  |  | 1     | 
|Office lease (2)              |  |       | 663   |  |                       |  | 62  |             |  |  | 111         |  |  |                 | 106   |  |  |  | 384   | 
|Long-term debt (3)(4)         |  |       | 2,690 |  |                       |  | 5   |             |  |  | 311         |  |  |                 | 1,210 |  |  |  | 1,164 | 
|Decommissioning liability (5) |  |       | 3,201 |  |                       |  | 107 |             |  |  | 214         |  |  |                 | 214   |  |  |  | 2,666 | 
|                              |  |       |       |  |                       |  |     |             |  |  |             |  |  |                 |       |  |  |  |       | 
|Total                         |  |       | 7,146 |  |                       |  | 260 |             |  |  | 813         |  |  |                 | 1,648 |  |  |  | 4,425 | 
|                              |  |       |       |  |                       |  |     |             |  |  |             |  |  |                 |       |  |  |  |       | 



|(1) | These amounts represent estimated commitments of $13 million for CO2 purchases and $6 million for processing fees related to interests in the Weyburn Unit.
|--- | -----------------------------------------------------------------------------------------------------------------------------------------------------------

|(2) | Future office lease commitments will be reduced by sublease recoveries of $335 million.
|--- | ---------------------------------------------------------------------------------------

|(3) | Penn Wests syndicated bank facility is due for renewal on June 30, 2016. Penn West and its predecessor have successfully extended its credit facility on each
renewal date since 1992.
|--- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

|(4) | Interest payments have not been included since future debt levels and rates are not known at this time.
|--- | -------------------------------------------------------------------------------------------------------

|(5) | These amounts represent the undiscounted future reclamation and abandonment costs that are expected to be incurred over the life of the properties.
|--- | ---------------------------------------------------------------------------------------------------------------------------------------------------

Identification of the Audit Committee.

Penn West has a separately-designated standing audit committee established in accordance with Section 3(a)(58)(A) of the Exchange Act. The members of the audit committee are: James C. Smith, James E.
Allard, Gillian H. Denham, George H. Brookman and Frank Potter.

Mine Safety Disclosure.

Not applicable.

Disclosure Pursuant to the
Requirements of the New York Stock Exchange.

Presiding Director at Meetings of Non-Management Directors

Penn West schedules regular executive sessions in which Penn Wests non-management directors (as that term is defined in the rules of the
New York Stock Exchange) meet without management participation. John A. Brussa, the Chairman of the board of directors, serves as the presiding director (the Presiding Director) at such sessions. Penn Wests board of directors is
responsible for determining whether or not each director is independent. In making this determination, the board of directors has adopted the definition of independence as set out in Section 1.4 of Multilateral Instrument 52-110
Audit Committees (MI 52-110). In applying this definition, the board of directors considers all relationships of the directors with Penn West, including business, family and other relationships. Penn Wests board of directors also
determines whether each member of Penn Wests audit committee is independent pursuant to Sections 1.4 and 1.5 of MI 52-110 and Rule 10A-3 under the Exchange Act. Penn Wests board of directors has not adopted the director independence
standards contained in Section 303A.02 of the NYSEs Listed Company Manual.



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Communication with Non-Management Directors

Shareholders may send communications to Penn Wests non-management directors by writing to George H. Brookman, Chairman of the
governance committee of the board of directors, care of Investor Relations, Penn West Petroleum Ltd., 200, 207 
9thAvenue SW, Calgary, Alberta, T2P 1K3 Canada.
Communications will be referred to the Presiding Director for appropriate action. The status of all outstanding concerns addressed to the Presiding Director will be reported to the board of directors as appropriate.

Corporate Governance Guidelines

In
accordance with the rules of the New York Stock Exchange, Penn West has adopted corporate governance guidelines, entitled Governance Guidelines, which are available for viewing on Penn Wests website at www.pennwest.com and are
available in print to any shareholder who requests a copy of them. Requests for copies of the Governance Guidelines should be made by contacting: investor relations by phone (888) 770-2633 or by e-mail to investor_relations@pennwest.com.

Board Committee Mandates

The Mandates of Penn Wests audit committee, human resources and compensation committee, governance committee, reserves and A&D committee and
health, safety and environment committee are each available for viewing on Penn Wests website at www.pennwest.com, and are available in print to any shareholder who requests them. Requests for copies of these documents should be made by
contacting: investor relations by phone (888) 770-2633 or by e-mail to investor_relations@pennwest.com.

NYSE Statement of Governance
Differences

As a Canadian corporation listed on the NYSE, Penn West is not required to comply with most of the NYSE corporate governance
standards, so long as it complies with Canadian corporate governance practices. In order to claim such an exemption, however, Penn West must disclose the significant difference between its corporate governance practices and those required to be
followed by U.S. domestic companies under the NYSEs corporate governance standards. Penn West has included a description of such significant differences in corporate governance practices on its website which may be accessed at
www.pennwest.com.



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UNDERTAKING AND CONSENT TO SERVICE OF PROCESS

A. Undertaking.

Penn
West undertakes to make available, in person or by telephone, representatives to respond to inquiries made by the Commission staff, and to furnish promptly, when requested to do so by the Commission staff, information relating to: the securities
registered pursuant to Form 40-F; the securities in relation to which the obligation to file an annual report on Form 40-F arises; or transactions in said securities.

B. Consent to Service of Process.

Penn West has previously filed a Form
F-X in connection with the class of securities in relation to which the obligation to file this report arises.

Any change to
the name or address of the agent for service of process of Penn West shall be communicated promptly to the Commission by an amendment to the Form F-X referencing the file number of Penn West.

SIGNATURES

Pursuant to the requirements of the Exchange Act, Penn West Petroleum Ltd. certifies that it meets all of the requirements for filing on Form 40-F and has duly caused this annual report to be signed on
its behalf by the undersigned, thereunto duly authorized, on March 14, 2013.



Penn West Petroleum Ltd.By:

/s/ Murray R. NunnsName: Murray R. NunnsTitle:   President & Chief Executive Officer




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EXHIBIT INDEX



|        |  |                                                                                                                                  
|------- |  | ---------------------------------------------------------------------------------------------------------------------------------
|Exhibit |  | Description                                                                                                                      
|        | 
|99.1    |  | Annual Information Form for the fiscal year ended December 31, 2012                                                              
|        | 
|99.2    |  | Managements Discussion and Analysis of Financial Condition and Results of Operations for the fiscal year ended December 31, 2012
|        | 
|99.3    |  | Consolidated Financial Statements for the fiscal year ended December 31, 2012                                                    
|        | 
|99.4    |  | Supplemental Oil and Gas information                                                                                             
|        | 
|99.5    |  | Certification of President & Chief Executive Officer pursuant to Rule 13a-14(a) or 15d-14 of the Securities Exchange Act of 1934 
|        | 
|99.6    |  | Certification of Chief Financial Officer pursuant to Rule 13a-14(a) or 15d-14 of the Securities Exchange Act of 1934             
|        | 
|99.7    |  | Certification of Chief Executive Officer pursuant to 18 U.S.C. Section 1350                                                      
|        | 
|99.8    |  | Certification of Chief Financial Officer pursuant to 18 U.S.C. Section 1350                                                      
|        | 
|99.9    |  | Consent of KPMG LLP                                                                                                              
|        | 
|99.10   |  | Consent of GLJ Petroleum Consultants Ltd.                                                                                        
|        | 
|99.11   |  | Consent of Sproule Associates Limited