Gran Tierra Spuds Wells in Argentina, Mobilizes Rigs in Colombia

Gran Tierra Energy Inc. said Wednesday that it has initiated drilling operations in Argentina and is mobilizing three rigs in Colombia as part of a continuous drilling program scheduled through 2007.

Drilling commenced on the Puesto Climaco-2 sidetrack in the Vinalar block in Argentina on November 29. Gran Tierra holds a 50% working interest in this area. The deviated well has reached its planned depth of 3,713 meters, the target reservoir has been penetrated and logging activity has commenced. Results will be evaluated in the coming week. Production facilities associated with the Puesto Climaco field are in place and ready to accommodate additional production from the Puesto Climaco-2 sidetrack immediately if successful.

Also in Argentina, a workover rig is being mobilized to the Ipaguazu field to recomplete the IPX-1 well and re-establish production from this shut-in field. Gran Tierra holds a 100% working interest in the Ipaguazu block. These operations are expected to continue through the month of December.

In Colombia, a drilling rig is being mobilized to drill the Laura-1 prospect in the Talora block in the Middle Magdalena Basin. This well is scheduled to begin drilling in late December and reach target depth in early January 2007. Gran Tierra has a 20% carried working interest in this block.

A second rig is being prepared to move to drill the Caneyes-1 prospect in the adjacent Rio Magdalena block in Colombia in early January, 2007. Gran Tierra currently holds a 100% working interest in this contact area, which is subject to a 30% back-in provision by Ecopetrol, the government petroleum agency, in the event of commerciality. Completion of this well is expected in mid January, 2007.

A third drilling rig is currently being mobilized to drill the Juanambu-1 prospect in the Guayuyaco block in the Putumayo Basin of Colombia. Drilling is expected to commence by January 15, 2007. Gran Tierra's interest in this block is 35% after the Ecopetrol back-in. The rig is planned to be moved to the adjacent Chaza block to drill the Naboyaco-1 prospect in February 2007. Gran Tierra Energy holds a 50% working interest in the Chaza contact area.

Five additional new wells are scheduled to be drilled in Colombia and Argentina over the first three quarters of 2007 by the Company. A significant work-over program is also planned for the year to enhance production from existing wells.

Dana Coffield, President and Chief Executive Officer of Gran Tierra, stated "The onset of simultaneous drilling operations in our two primary operational arenas, Argentina and Colombia, and the imminent expansion of this drilling program in early 2007 puts substance to our dual strategy of acquiring prospective and underdeveloped lands, and adding production through the drill bit."

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