Oil and Gas Information AdvisoryBarrels of oil equivalent ("boe") may be misleading, particularly if used in isolation. A boe conversion ratio of six thousand cubic feet of natural gas to one barrel of crude oil is based on an energy equivalency conversion method primarily applicable at the burner tip and does not represent a value equivalency at the wellhead. Given that the value ratio based on the current price of crude oil as compared to natural gas is significantly different from the energy equivalency conversion ratio of 6:1, utilizing a conversion on a 6:1 basis is misleading as an indication of value. Contingent Resource Disclosures In this press release, Penn West discusses the results of two recently completed independent resource evaluation studies which include an AJM Deloitte ("AJM") contingent resource evaluation effective July 31, 2012, for Penn West's Cardium properties and a Sproule Unconventional Limited ("Sproule") contingent resource evaluation report effective September 30, 2012 for Penn West's interest in the Peace River Oil Partnership (the "PROP"). Penn West holds a 55 percent interest in PROP and all figures presented in this release in respect of PROP assets reflect Penn West's 55 percent interest. This release contains certain information reproduced from both the AJM Report and the Sproule Report, but does not contain either report in its entirety. AJM has assigned contingent resources of 533 million barrels of oil in the best estimate case for Penn West's Cardium properties. Sproule has assigned contingent resources of 473 million barrels of bitumen in the best estimate case for Penn West's interest in the PROP assets. The contingent resource assessments prepared by AJM and Sproule were prepared in accordance with the definitions, standards and procedures contained in the Canadian Oil and Gas Evaluation Handbook (the "COGE Handbook") and NI 51-101. Contingent resource is defined in the COGE Handbook as those quantities of petroleum estimated to be potentially recoverable from known accumulations using established technology or technology under development, but which do not currently qualify as reserves or commercially recoverable due to one or more contingencies. Contingencies may include factors such as economic, legal, environmental, political and regulatory matters or a lack of markets. There is no certainty that it will be commercially viable to produce any portion of the contingent resources.