Pacific Rubiales Energy Corp. (Pacific Rubiales) said that Petrotech Engineering Ltd. has provided an independent reserve evaluation of the Rubiales/Piriri field, with an effective date of June 30, 2009. The Rubiales/Piriri field had proved reserves (P1) of 341.3 MMbbl at June 30, 2009 compared with 286.4 MMbbl at December 31, 2008; and proved plus probable reserves (P1+P2) of 397.4 MMbbl at June 30, 2009 compared with 361.5 at December 31, 2008.

An additional 199.1 MMbbl may be classified as probable and possible reserves if production should go beyond May 2016 (which is the date the company is currently obligated to revert the fields back to Ecopetrol).

The reserve evaluation update was prepared to take into consideration the drilling of 48 horizontal and vertical wells as well as production of 10.26 MMbbl of heavy oil (million barrels of oil) in the first six months of this year.

Total net after royalty proved reserves (calculated in accordance with National Instrument 51-101 “Standards of Disclosure for Oil and Gas Activities” (NI 51-101)) were 117.1 MMbbl at June 30, 2009 compared with 99.3 MMbbl at year-end 2008, an increase of 18%. Total net after royalty proved plus probable reserves (calculated in accordance with NI 51-101) were 134.9 MMbbl at June 30, 2009 compared with 124.7 MMbbl at year-end 2008, an increase of 10%.

The reserve data in 2008 and 2009 have been determined in accordance with NI 51-101 and the Canadian Oil and Gas (COGE) Handbook by Petrotech Engineering Ltd., an independent qualified reserve evaluator. The reserve estimates in this release are based on forecast prices and costs and are estimates only. Actual reserves on the company’s properties may be greater or less than those calculated. Under the National Instrument 51-101 guidelines, proved reserves are reserves that have a 90% chance of being exceeded at the reported level. Proved reserves, by definition, are conservative. Nine times out of ten actual reserves will be greater than the proved estimate. Proved plus probable reserves are defined as those reserves that have a 50% probability of being exceeded at the reported level. They are the best estimate, or the most realistic case. Proved plus probable plus possible reserves are at least a 10% probability that the quantities actually recovered will equal or exceed at the reported level. It is equally likely that the actual reserves will be higher or lower than the estimate.