NEWSROOM

TORONTO, May 28, 2012 /CNW/ - Pacific Rubiales Energy Corp. (TSX: PRE; BVC: PREC; BOVESPA: PREB) is pleased to announce that it has agreed to purchase 85,714,285 units of CGX Energy Inc. (TSX-V: OYL) ("CGX") at a price of C$0.35 per unit for an aggregate investment of C$30 million. At the same time, the Company has entered into a technical services agreement with CGX whereby Pacific Rubiales will provide technical assistance to CGX in respect of its operations. In addition the Company will have an option to participate in each of the next wholly owned commitment wells to be drilled on the Corentyne and Annex offshore Petroleum Production Licences ("PPL"), in Guyana, by funding 50% of the exploration well costs and certain seismic costs, in exchange for a 33% interest in the respective PPL's.

Ronald Pantin, Chief Executive Officer of the Company, commented: "This is a great opportunity for the Company to expand its investment in the highly prospective offshore Guyana oil play. Through our ownership in CGX, the technical services agreement and a direct earning option, the Company will be participating in an exploration campaign in an offshore basin with analogous geology to West Africa and Brazil. We are looking forward to working with the management of CGX on realizing the potential of offshore Guyana. This investment is strategic to the Company's objective of being the leading Latin American independent explorer and producer of hydrocarbons."

The purchase of the units is being accomplished by way of a private placement offering by CGX. Each unit will consist of one common share of CGX plus one half of one common share warrant. Each warrant will entitle the Company to purchase one additional common share of CGX at an exercise price of C$0.60 within an 18 month period following issuance of the units. The units are expected to be issued within a week following the required TSX Venture Exchange and CGX shareholder approval.

Pacific Rubiales currently owns 58.7 million shares of CGX, which were acquired by the Company through a bought deal financing that closed in October 2011. Upon issuance of the units, the Company will hold approximately 35% of the issued and outstanding common shares of CGX on a non-fully diluted basis. The Company will also be entitled to nominate up to three directors to serve on CGX's board of directors.

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 Rubiales, Piriri and Quifa oil fields in the Llanos Basin in association with Ecopetrol, S.A., the Colombian national oil company, and 100 percent of Pacific Stratus Energy Corp. which operates the La Creciente natural gas field. 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 working interests in 43 blocks in Colombia, Peru and Guatemala. The Company's common shares trade on the Toronto Stock Exchange and La Bolsa de Valores de Colombia and as Brazilian Depositary Receipts on Brazil's Bolsa de Valores Mercadorias e Futuros under the ticker symbols PRE, PREC, and PREB, respectively.

CGX is a Canadian oil and gas exploration company that holds four licenses in the Guyana Suriname basin, a frontier basin in South America with a proven hydrocarbon system and highly prospective deep water plays that can be drilled in shallow water. The United States Geological Survey (USGS) has identified the Guyana Suriname basin as having the second highest resource potential among unexplored oil basins in the world. The common shares of CGX trade on the TSX Venture Exchange under the symbol OYL.

Advisories

Cautionary Note Concerning Forward-Looking Statements

This news 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, Guatemala 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 14, 2012 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 an accordingly undue reliance should not be put on such statements due to the inherent uncertainty therein.