2010-08-31-2010-08-30

To acquire a 70% working interest in Blocks REC-T-129, -142, -155 and -224 in the onshore Reconcavo Basin in Brazil.

Gran Tierra Energy Inc., Calgary, (NYSE Amex; Toronto: GTE) plans to acquire a 70% working interest in Blocks REC-T-129, -142, -155 and -224 in the onshore Reconcavo Basin in Brazil from Alvorada Petroleo SA for US$22.6 million.

Gran Tierra Energy is expected to fulfill certain commitments, including in part, the drilling of two wells in 2011 to farm in to the blocks.

Under the terms of the agreement, Gran Tierra Energy will operate the blocks and will pay 100% of the costs to drill an exploration well on each of Blocks REC-T-129 and -142, and its working interest share of the 130 km2 3D seismic program currently being conducted on all four blocks. These blocks were awarded to Alvorada through Brazil's 9th ANP bid round.

Earlier this year, an oil discovery was made on Block REC-155. The current gross production from the discovery is approximately 500 barrels of oil per day from the Sergi formation. Gran Tierra Energy anticipates drilling additional wells to further delineate this discovery and potentially increase production and reserves from the field. This discovery currently has unaudited estimated gross recoverable resources of 6 million barrels of oil.

In addition to the current oil discovery on Block REC-155, Gran Tierra Energy has identified a new oil resource play that would potentially employ multi-staged frac horizontal well technology and intends to investigate this opportunity with Alvorada Petroleo.

"This farm-in opportunity presents Gran Tierra Energy with a solid entry-point into Brazil, with new light oil reserves, production and exploration upside, including near-term drilling opportunities," says Gran Tierra president and chief executive Dana Coffield."Gran Tierra Energy continues to evaluate additional exploration and production opportunities in Brazil, with the intention of expanding our presence in Brazil's growing oil and gas sector."

The Reconcavo Basin covers an area of approximately 10,000 km2, contains 129 oil and gas fields and has produced more than 1.5 billion barrels of oil to date. Production from this basin is characterized by light oil ranging between 35 degrees and 40 degrees API.

The transaction is subject to Gran Tierra Energy obtaining the customary regulatory approval from Brazil's Agencia Nacional de Petroleo Gas Natural e Biocombustiveis ("ANP").

Gran Tierra has oil and gas assets in South America, primarily Colombia, Argentina and Peru.