Gran Tierra Tests Oil in Juanambu-1

Gran Tierra Energy Inc. on Monday said that it has successfully completed two drill stem tests in the Juanambu-1 exploration well in the Guayuyaco Block, Putumayo Basin, in southern Colombia.

Stabilized flow of 32 degrees API oil with constant well-head flowing pressure was obtained in two independent drill stem tests, one in the Lower Caballos Formation and one in the Middle Caballos Formation. After initial swabbing, sustained stable oil flow was attained in both tests without supplementary pumping, which is typically required in this region. The testing program is continuing, with four separate drill stem tests planned over four additional reservoir zones that had good hydrocarbon shows during drilling. The Villeta T Sand interval, which is the primary reservoir objective, is one of the remaining test intervals. Detailed results will be announced upon completion of the testing program.

Gran Tierra Energy holds a 50% working interest and is Operator of this block. Partner, Solana Resources Limited, holds a 50% working interest and Ecopetrol has a 30% interest back-in right on commercial discoveries. Should Ecopetrol exercise its back-in right, Gran Tierra Energy will hold a 35% working interest and Operatorship, and Solana Resources Limited will hold a 35% working interest in the new commercial field.

The Costayaco-1 exploration well in the adjacent Chaza Block is currently drilling and is expected to penetrate the target formations within the next two to three weeks. Gran Tierra is the operator of the Chaza block with a 50% working interest.

Dana Coffield, President and CEO stated, "We are extremely pleased with the natural flow of oil to surface achieved during the first two tests, and look forward to the remaining tests, in particular over the Villeta T Sand - our primary reservoir objective."

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. Gran Tierra holds interests in producing and prospective properties in Argentina, Colombia and Peru.