NEWSROOM

    TORONTO, Sept. 3 /CNW/ - Pacific Rubiales Energy Corp. (TSX: PRE)
announced today that it has received a Statement of Reserves Data for the
Rubiales-Piriri field.
    Petrotech Engineering Ltd. has provided an independent reserve evaluation
of the Rubiales/Piriri field, with an effective date of June 30, 2009. 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.
    According to the Petrotech Statement of Reserves Data, 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).
    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%.Petrotech Reserves at June 30, 2009
    -----------------------------------

                                                              PRE    PRE Net
    Heavy Oil                                    Gross    Working      After
                                              Reserves   Interest    Royalty
                                      (Rubiales/Piriri)  Reserves   Reserves
    Reserves Category                             Mbbl       Mbbl       Mbbl
    Proved
      Developed Producing                       73,215     31,764     25,411
      Developed Non-Producing                    1,944        904        723
        Undeveloped                            267,145    113,670     90,936
    Total Proved                               341,304    146,337    117,070
    Total Probable                              56,113     22,296     17,837
    Total Proved Plus Probable                 397,417    168,633    134,906The 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.
    The Petrotech Statement of Reserves Data will be filed by the company on
SEDAR by the end of next week.

    Pacific Rubiales, a Canadian-based company and producer of natural gas
and heavy crude oil, owns 100 percent of Meta Petroleum Corp., a Colombian oil
operator which operates the Quifa block in the Llanos Basin in association
with Ecopetrol S.A., the Colombian national oil company. The company is
focused on identifying opportunities primarily within the eastern Llanos Basin
of Colombia as well as in other areas in Colombia and northern Peru. Pacific
Rubiales has a current net production of approximately 34,000 barrels of oil
equivalent per day, with working interests in 32 blocks in Colombia and Peru.

    Cautionary Note Concerning Forward-Looking Statements

    This press release contains forward-looking statements. All statements,
other than statements of historical fact, that address activities, events or
developments that the company believes, expects or anticipates will or may
occur in the future (including, without limitation, statements regarding
estimates and/or assumptions in respect of production, revenue, cash flow and
costs, reserve and resource estimates, potential resources and reserves and
the company's exploration and development plans and objectives) are
forward-looking statements. These forward-looking statements reflect the
current expectations or beliefs of the company based on information currently
available to the company. Forward-looking statements are subject to a number
of risks and uncertainties that may cause the actual results of the company to
differ materially from those discussed in the forward-looking statements, and
even if such actual results are realized or substantially realized, there can
be no assurance that they will have the expected consequences to, or effects
on the company. Factors that could cause actual results or events to differ
materially from current expectations include, among other things: uncertainty
of estimates of capital and operating costs, production estimates and
estimated economic return; the possibility that actual circumstances will
differ from the estimates and assumptions; failure to establish estimated
resources or reserves; fluctuations in petroleum prices and currency exchange
rates; inflation; changes in equity markets; political developments in
Colombia or Peru; changes to regulations affecting the company's activities;
uncertainties relating to the availability and costs of financing needed in
the future; the uncertainties involved in interpreting drilling results and
other geological data; and the other risks disclosed under the heading "Risk
Factors" and elsewhere in the company's annual information form dated March
28, 2008 filed on SEDAR. Any forward-looking statement speaks only as of the
date on which it is made and, except as may be required by applicable
securities laws, the company disclaims any intent or obligation to update any
forward-looking statement, whether as a result of new information, future
events or results or otherwise. Although the company believes that the
assumptions inherent in the forward-looking statements are reasonable,
forward-looking statements are not guarantees of future performance and
accordingly undue reliance should not be put on such statements due to the
inherent uncertainty therein.

    %SEDAR: 00007953E