Reserves

Summary of Reserves

In 2016, we engaged Sproule Associates Limited ("Sproule"), an independent, qualified engineering firm, to evaluate one hundred percent of our proved and proved plus probable reserves. Sproule conducted an independent reserves evaluation of Penn West's reserves effective December 31, 2016. This evaluation was prepared in accordance with definitions, standards, and procedures set out in the Canadian Oil and Gas Evaluation Handbook ("COGEH") and National Instrument 51-101 Standards of Disclosure for Oil and Gas Activities ("NI 51-101"). The Sproule reserves evaluation was based on Sproule's December 31, 2016 product price forecast.

Under NI 51-101, proved reserves estimates are defined as having a high degree of certainty to be recoverable with a targeted 90 percent probability in aggregate that actual reserves recovered over time will equal or exceed proved reserve estimates. For proved plus probable reserves under NI 51-101, the targeted probability is an equal (50 percent) likelihood that the actual reserves to be recovered will be greater or less than the proved plus probable reserves estimate. The reserves estimates set forth below are estimates only and there is no guarantee that the estimated reserves will be recovered. Actual reserves may be greater than or less than the estimates provided herein.

The Summary of Reserves tables below are based on Sproule's evaluation at December 31, 2016 using Sproule's December 31, 2016 product price forecast. All reserve volumes are company gross unless otherwise noted.

Total Company Gross (WI) Reserves
As at December 31, 2016
Reserves Estimates Category(1)(2)
Light & Medium Crude Oil (mmbbl) Heavy Crude Oil & Bitumen (mmbbl) Natural Gas Liquids (mmbbl) Conventional Natural Gas
(bcf)
Barrels of Oil Equivalent (mmboe)
Proved
Developed producing 41 8 6 236 94
Developed non-producing 2 0 1 19 6
Undeveloped 10 2 1 23 17
Total Proved 54 10 7 278 117
Probable 21 5 3 97 44
Total Proved plus Probable 75 14 10 374 161

(1) Company gross (WI) reserves are before royalty burdens and exclude royalty interests.
(2) Columns and rows may not add due to rounding.

Total Company Net after Royalty Interest Reserves
As at December 31, 2016
Reserves Estimates Category(1)(2)
Light & Medium Crude Oil (mmbbl) Heavy Crude Oil & Bitumen (mmbbl) Natural Gas Liquids (mmbbl) Conventional Natural Gas
(bcf)
Barrels of Oil Equivalent (mmboe)
Proved
Developed producing 38 7 5 209 84
Developed non-producing 2 0 1 16 5
Undeveloped 9 2 1 21 15
Total Proved 49 9 6 246 105
Probable 19 4 2 87 39
Total Proved plus Probable 68 12 8 333 144

(1) Net after royalty reserves are working interest reserves including royalty interests and deducting royalty burdens.
(2) Columns and rows may not add due to rounding.

Additional reserve disclosures, as required under NI 51-101, will be contained in our Annual Information Form that will be filed on SEDAR at www.sedar.com.