NEWSROOM

    TORONTO, July 28 /CNW/ - Pacific Rubiales Energy Corp. (TSX: PEG)
announced today the filing on SEDAR (www.sedar.com) of the independent reserve
and resource assessment report (the Petrotech Report) prepared by Petrotech
Engineering Ltd., of Burnaby, Canada, relating to the current resource base of
Kappa Energy Holdings Ltd., which the company announced on July 7, 2008 it was
proposing to acquire. The Petrotech Report, which exceeded management
expectations, further enhances Pacific Rubiales' reserve base and adds to its
already deep inventory of prospects.
    "Given the commitment prices paid on the recent heavy oil licensing round
and the increased interest demonstrated by our peers in Colombia, we are
thrilled to be in a position to acquire Kappa at such attractive metrics,"
said Ronald Pantin, Chief Executive Officer.
    "Pacific Rubiales is excited to begin work on the vast reserve base of
Kappa and to begin capitalizing on its large resource potential," said Jose
Francisco Arata, President.
    The Petrotech Report provides the following summary of Kappa's net share
of total proved (developed producing, developed non-producing, undeveloped),
probable and possible reserves from the nine blocks in which it currently
holds interests:-------------------------------------------------------------------------
    Reserve Category       L&M Crude          Heavy Oil             Gas
                         Gross    Net       Gross    Net       Gross    Net
    Proved Reserve       (Mbbl)  (Mbbl)     (Mbbl)  (Mbbl)     (MMcf)  (MMcf)
    Producing              622     591          -       -        907     789
    Non-Producing            -       -          -       -        348     326
    Undeveloped          2,087   1,808        192     181     15,834  13,244
    Total Proved         2,709   2,399        192     181     17,090  14,359

    Proved+Probable      3,821   3,370      2,430   2,271     24,420  20,451

    Proved+Probable
     +Possible           4,557   3,994     14,468  13,507     31,195  26,053
    -------------------------------------------------------------------------

    Additionally, the Petrotech Report indicated that a number of prospects
have been identified within the nine blocks that are the subject of the
report, for which prospective resources have been evaluated as follows:

    -------------------------------------------------------------------------
    Resources              L&M Crude          Heavy Oil             Gas
                         Gross    Net       Gross    Net       Gross    Net
                         (Mbbl)  (Mbbl)     (Mbbl)  (Mbbl)     (MMcf)  (MMcf)
    Low Estimate        67,790  60,672     55,306  51,307     19,454  18,070
    Best Estimate       88,714  79,307     72,088  66,901     31,397  28,665
    High Estimate      111,093  99,348     89,966  83,448     49,237  44,573
    -------------------------------------------------------------------------The Petrotech reserve and resource estimates set out in this press
release were prepared in accordance with the requirements of Canadian National
Instrument 51-101 Standards of Disclosure for Oil and Gas Activities.
Capitalized terms related to resource classifications used in this press
release are based on the definitions and guidelines in the Canadian Oil and
Gas Evaluation Handbook (COGEH).
    Undiscovered resources are defined as those quantities of oil and gas
estimated on a given date to be contained in accumulations yet to be
discovered. The estimated potentially recoverable portion of undiscovered
resources is classified as prospective resources. Prospective resources are
defined as those quantities of oil and gas estimated on a given date to be
potentially recoverable from undiscovered accumulations. If discovered, they
would be technically and economically viable to recover. However, there is no
certainty that the prospective resources will be discovered. In addition, the
following mutually exclusive Classification of Resources was used:

    Low Estimate - This is considered to be a conservative estimate of the
quantity that will actually be recovered from the accumulation. This term
reflects a P90 confidence level where there is a 90% chance that a successful
discovery will be more than this resource estimate.

    Best Estimate - This is considered to be the best estimate of the
quantity that will actually be recovered from the accumulation. This term is a
measure of central tendency of the uncertainty distribution and in this case
reflects a 50% confidence level where the successful discovery will have a 50%
chance of being more than this resource estimate.

    High Estimate - This is considered to be an optimistic estimate of the
quantity that will actually be recovered from the accumulation. This term
reflects a P10 confidence level where there is a 10% chance that the
successful discovery will be more than this resource estimate.

    Petrotech has acted independently in the preparation of the Petrotech
Report. Petrotech and its employees have no direct or indirect ownership in
the properties appraised or the areas of study described in the report.

    Pacific Rubiales, a Canadian-based company and producer of natural gas
and heavy crude oil, owns 100 percent of Meta Petroleum Limited, a Colombian
oil operator which operates the Rubiales and Piriri oil fields 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
21,000 barrels of oil equivalent per day, with working interests in the
Rubiales, Piriri and Quifa concessions and the Caguan, Dindal, Rio Seco, Puli
B, La Creciente, Moriche, Guama, Arauca, Tacacho and Jagueyes blocks in
Colombia and blocks 135, 137 and 138 in Peru.

    All monetary amounts in U.S. dollars unless otherwise stated. This news
release contains certain "forward-looking statements" and "forward-looking
information" under applicable Canadian securities laws concerning the
business, operations and financial performance and condition of Pacific
Rubiales Energy Corp. Forward-looking statements and forward-looking
information include, but are not limited to, statements with respect to
estimated production and reserve life of the various oil and gas projects of
Pacific Rubiales; the estimation of oil and gas reserves; the realization of
oil and gas reserve estimates; the timing and amount of estimated future
production; costs of production; success of exploration activities; and
currency exchange rate fluctuations. Except for statements of historical fact
relating to the companies, certain information contained herein constitutes
forward-looking statements. Forward-looking statements are frequently
characterized by words such as "plan," "expect," "project," "intend,"
"believe," "anticipate", "estimate" and other similar words, or statements
that certain events or conditions "may" or "will" occur. Forward-looking
statements are based on the opinions and estimates of management at the date
the statements are made, and are based on a number of assumptions and subject
to a variety of risks and uncertainties and other factors that could cause
actual events or results to differ materially from those projected in the
forward-looking statements. Many of these assumptions are based on factors and
events that are not within the control of Pacific Rubiales and there is no
assurance they will prove to be correct. Factors that could cause actual
results to vary materially from results anticipated by such forward-looking
statements include changes in market conditions, risks relating to
international operations, fluctuating oil and gas prices and currency exchange
rates, changes in project parameters, the possibility of project cost overruns
or unanticipated costs and expenses, labour disputes and other risks of the
oil and gas industry, failure of plant, equipment or processes to operate as
anticipated, the business of Petro Rubiales and Pacific Stratus not being
integrated successfully or such integration proving more difficult, time
consuming or costly than expected as well as those risk factors discussed or
referred to in the annual Management's Discussion and Analysis and Annual
Information Form for Pacific Rubiales filed with the securities regulatory
authorities in all provinces of Canada and available at www.sedar.com.
Although Pacific Rubiales has attempted to identify important factors that
could cause actual actions, events or results to differ materially from those
described in forward-looking statements, there may be other factors that cause
actions, events or results not to be anticipated, estimated or intended. There
can be no assurance that forward-looking statements will prove to be accurate,
as actual results and future events could differ materially from those
anticipated in such statements. Pacific Rubiales undertakes no obligation to
update forward-looking statements if circumstances or management's estimates
or opinions should change except as required by applicable securities laws.
The reader is cautioned not to place undue reliance on forward-looking
statements. Statements concerning oil and gas reserve estimates may also be
deemed to constitute forward-looking statements to the extent they involve
estimates of the oil and gas that will be encountered if the property is
developed.
    Boe may be misleading, particularly if used in isolation. A boe
conversion ratio of 6 mcf:1 bbl is based on an energy equivalency conversion
method primarily applicable at the burner tip and does not represent a value
equivalency at the wellhead.

    %SEDAR: 00007953E