Pacific Rubiales Announced Operational Update at Quifa Block

BOGOTA, Oct. 26 /PRNewswire-FirstCall/ -- Ecopetrol (NYSE: EC and BMV: ECOPETROL) is Colombia's largest integrated oil company and is among the top 40 oil companies in the world and the four largest oil companies in Latin America. Besides Colombia, where it accounts for 60% of total production, the Company is involved in exploration and production activities in Brazil, Peru and the United States ( Gulf of Mexico). Ecopetrol has the principal refinery in Colombia, most of the network of oil and multiple purpose pipelines in the country, and it is considerably increasing its participation in biofuels.

(Logo: http://www.newscom.com/cgi-bin/prnh/20090209/ARM001LOGO )

This release contains forward-looking statements relating to the prospects of the business, estimates for operating and financial results, and those related to growth prospects of Ecopetrol. These are merely projections and, as such, are based exclusively on the expectations of management concerning the future of the business and its continued access to capital to fund the Company's business plan. Such forward-looking statements depend, substantially, on changes in market conditions, government regulations, competitive pressures, the performance of the Colombian economy and the industry, among other factors; therefore, they are subject to change without prior notice.

Contact us for any additional information:

Investor Relations Alejandro Giraldo Phone: +571-234-5190 Email: investors@ecopetrol.com.co

Media Relations (Colombia) Mauricio Tellez Phone: +571-2345377 Fax: +571-2344480 Email: mtellez@ecopetrol.com.co

Website: http://www.ecopetrol.com.co

Pacific Rubiales Energy Announces Another Exploration Success And Operational

Update at Quifa Block

TORONTO, Pacific Rubiales Energy Corp. (TSX: PRE) announced today another oil discovery at its Quifa-10 well on the Quifa Block, located in the Llanos Basin of Colombia. The company also provided an update on the operational activity in the block.

The Quifa-10 was drilled as an appraisal well of the discovery well Quifa-7 located at Prospect "H". The well found the top of the Carbonera basal sands at 2,889 feet measured depth (MD), or 2,229 feet true vertical depth at sub-sea level (TVDSS) and the oil water contact (OWC) at 2,933 feet MD, or 2,273 feet TVDSS, for a total oil column of 44 feet. The petrophysical evaluation of the well indicates a net pay zone of 20 feet with 32% average porosity. The Quifa-10 well was drilled at a distance of 1.1 kilometers from the Quifa-7 well and at 2.0 kilometers of the Quifa-8 well in Prospect "E" (refer to the drill results of the Quifa-7 and Quifa-8 wells, in the company's press release dated September 8, and August 26, 2009, respectively). This well extends the discovery of Prospect "H" to the north and also extends the discovery of Prospect "E" to the south, resulting in a total hydrocarbon column of more than 100 feet for both prospects, with an average net pay of 24 feet. The results obtained with this well reinforce the company's belief that the area comprising prospects "D," "E," "H" and "I" are connected to the Rubiales field and we are just appraising this reservoir into the Quifa Block. The company is now planning to test the well and complete it as a vertical hole producer.

Operational update and new drilling campaign

An updated average production for the Quifa-5, Quifa-7, Quifa-8 and Quifa-9 wells is summarized in the table below. The production test on Quifa-I-9 is still pending and waiting for a mechanical condition to be solved at the well bore.

Well Production period Average bopd ------------------------------------------------------------- Quifa-5 6 months 192 ------------------------------------------------------------- Quifa-7 28 days 170 ------------------------------------------------------------- Quifa-8 25 days 134 ------------------------------------------------------------- Quifa-9 15 days 119

As a result of the exploration success in the Quifa Block, an additional drilling campaign comprising 6 appraisals and 3 exploratory wells will be executed during 2009. The three exploratory wells will be drilled on prospects "A," "B" and "C" and the six appraisal wells will be spudded on prospects "D," "E" and "H". The appraisal wells represent the initiation of the process to declare the commerciality for the south-southwest region of the Quifa Block.

The Quifa Block is an exploratory block in which Meta Petroleum (a wholly owned subsidiary of Pacific Rubiales) holds a 60% working interest and Ecopetrol S.A. holds a 40% working interest.

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 45,000 barrels of oil equivalent per day, with working interests in 32 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 April 1, 2009 filed on SEDAR at http://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.

For further information:

Mr. Ronald Pantin, Chief Executive Officer and Director

Mr. Jose Francisco Arata President and Director (416) 362 7735

Ms. Belinda Labatte (647) 428 7035

SOURCE Ecopetrol S.A.