NEWSROOM

    TORONTO, April 7 /CNW/ - Ecopetrol, S.A. (BVC: ECOPETROL; NYSE: EC) and
Pacific Rubiales Energy Corp. (TSX: PRE) announced today that they have
executed a Memorandum of Understanding to pursue the evaluation of
Synchronized Thermal Additional Recovery (STAR) technology at the Rubiales
field, located in Los Llanos Orientales basin in Colombia.
    The evaluation is aimed at determining the feasibility of applying the
technology at a commercial scale, with the purpose of increasing the recovery
factor of the field, i.e., the volume of reserves that can be produced. Both
companies are of the opinion that the utilization of this technology will
leverage the continuous development of the heavy oil resources in the
Colombian basins.
    Under the Memorandum of Understanding, Pacific Rubiales will coordinate
and finance laboratory tests, already underway in Canada, from which it will
determine the engineering parameters to develop a pilot project to be
implemented in a selected number of wells at the Rubiales field.
    The Memorandum of Understanding not only outlines the mechanisms by which
both companies will ascertain the success of the tests and pilot project, but
also establishes a path forward to the structuring of an eventual contract
between the two of them for the commercial application of the technology in
the Rubiales field.
    The STAR technology is based on concepts of "in situ" combustion,
modified by Pacific Rubiales' proprietary knowledge and experience to suit the
specific physical conditions of the Rubiales reservoir and the specific
drainage pattern used in the present primary recovery development.
    The Rubiales field is presently producing a little over 58,000 barrels
per day of heavy crude and is operated by Meta Petroleum (a 100% affiliate of
Pacific Rubiales) under the Rubiales Risk Participation Contract and the
Piriri Association Contract, in which Ecopetrol and Pacific Rubiales hold
60/40% and 50/50% interests, respectively.

    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
34,000 barrels of oil equivalent per day, with working interests in 34 blocks
in Colombia and Peru.
    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.

    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 at www.sedar.com. 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