Gran Tierra Completes Popa-1 in Colombia

Gran Tierra Energy Inc. said that it has completed the drilling and logging of a new field wildcat well in the Rio Magdalena Block, located in the Middle Magdalena Basin of Colombia. Popa-1 was spudded on June 8, 2006, and drilled to a final measured depth of 9,285 feet on July 14, 2006.

Significant light oil and gas shows were encountered during drilling below 8,700 feet, and subsequent logging of the well indicates hydrocarbons are present. A testing program has now been initiated to evaluate the commercial potential of the two most prospective oil-bearing zones. This testing program is expected to require approximately 1 week to complete.

Popa-1 is a commitment well in the third phase of the Rio Magdalena Association Contract. Gran Tierra is the operator of the block via its acquisition of Argosy Energy International, which was completed on June 20, 2006. The company currently holds a 100% working interest in the block. Ecopetrol, the state company, has a right to a 30% participation subject to commerciality, and a sliding scale royalty applies.

The Popa well is the first to be completed by Gran Tierra since its entry into Colombia. Gran Tierra/Argosy operates seven contract areas in Colombia, two producing a total of approximately 2,700 barrels of oil per day gross (800 barrels of oil per day, net after royalty, June 2006). It plans to participate in seven additional exploration wells in Colombia in the next 18 months.

Gran Tierra Energy, Inc. is an international oil and gas exploration and production company, headquartered in Calgary, Canada, incorporated and traded in the United States and operating in South America. The company now holds interests in producing and prospective properties in Argentina, Colombia, and Peru. To date, the company has pursued a strategy that focuses on establishing a portfolio of producing properties, development and exploration opportunities, through selective acquisitions, to provide a base for future growth.

Gran Tierra is advancing a multi-well work program for 2006/early 2007 and expects to continue its strategy of moving aggressively and sensibly to build a diverse, self-sustaining and active international oil and gas company.