Gran Tierra provided initial drilling results in Colombia, Brazil and Argentina.

"Substantive progress has been made in our fourth quarter drilling program to date. We have completed the coring and drilling of our first pilot hole for our horizontal drilling program onshore in Brazil, and are now executing on our development drilling program in Argentina with good initial results. In contrast, our initial exploration drilling results in Colombia have been disappointing," said Dana Coffield, President and Chief Executive Officer of Gran Tierra Energy.

"With one exploration well currently drilling and a second exploration well poised to begin drilling in Colombia, we remain focused on the potential for additional reserve growth this year. We are very excited with where the company is today, with its large prospect inventory on our very large land position, and we anticipate our ongoing exploration and development program, which will continue through 2012, will be funded from cash and cash flow in the coming year," concluded Coffield.

Colombia

Rumiyaco Block (Gran Tierra Energy 100% WI and Operator)

The Rumiyaco-1 exploration well reached total depth (TD) in basement at 10,648 feet measured depth (MD) on November 19, 2011. Mud log and electric log data acquired during and after drilling indicate only non-commercial hydrocarbons present.

Sierra Nevada Block (Gran Tierra Energy 100% WI and Operator)

Drilling of the Brillante SE-2 delineation well reached TD of 5,520 feet MD on November 6, 2011. This well was drilled on the adjacent fault block to the Brillante SE-1 gas field that was discovered in 2010 in the Lower Magdalena Basin in northern Colombia. Mud log, electric log, and pressure gradient data acquired during and after drilling indicates no reservoir is present, so the well has been plugged and abandoned. New 3-D seismic data indicates the original fault block with the discovery well is larger than originally interpreted from old 2-D seismic data; future drilling will focus on proving additional reserves in that new area.

Llanos-22 Block (CEPSA 55% WI and Operator, Gran Tierra Energy 45% WI subject to ANH approval)

The Ramiriqui-1 oil exploration well in the Llanos-22 block, located in the Andean foothills trend of the Llanos Basin, is currently drilling ahead and is expected to reach TD in late December.

Chaza Block (Gran Tierra Energy 100% WI and Operator)

The Pacayaco-1 ST1 oil exploration well on the Chaza block of the Putumayo basin is expected to spud on December 10, 2011 and is expected to take 25 days to drill. The Pacayaco-1 ST1 well is targeting the same reservoir intervals present at Gran Tierra Enegy’s Costayaco and Moqueta discoveries.

Brazil

REC-T-142 Block (Gran Tierra Energy 70% WI & Operator, Alvorada 30% WI)

Drilling of the 1-GTE-01-BA oil exploration well was completed on November 24, 2011. The well is located in Block REC-T-142 in the prolific onshore Recôncavo Basin. This operation commenced with the drilling of a vertical pilot hole from which core samples were acquired from the prospective reservoir section. Gran Tierra Energy plans to drill a horizontal sidetrack from the pilot hole to test the productivity of the light oil sandstone reservoir target in late December. Two additional horizontal wells testing similar sandstone reservoirs are anticipated to be drilled in early 2012.

REC-T-129 Block (Gran Tierra Energy 70% WI & Operator, Alvorada 30% WI)

Drilling of the 1-GTE-02-BA oil exploration well began on November 23, 2011. This well is located in Block REC-T-129 in the Recôncavo Basin. The well is expected to reach a TD of approximately 6,068 feet MD and take approximately 32 days to drill.

REC-T-155 Block (Gran Tierra Energy 70% WI & Operator, Alvorada 30% WI)

Drilling of the 3-GTE-03-BA delineation well began on December 1, 2011. This well is located in Block REC-T-155 in the Recôncavo Basin and is situated 1.2 kilometers north of the 1-ALV-2-BA discovery well. Upon completion of the delineation well, this drilling rig is expected to return to Block REC-T-142 to drill the horizontal sidetrack well.

Argentina

Puesto Morales / Puesto Morales Este Blocks, Neuquen Basin

Gran Tierra Energy has completed drilling PME.a-1003, the first of four new development wells in the Puesto Morales field, with the purpose of improving recovery and growing production from this mature oil field. The well is being completed for production. Since taking over operatorship in March, the production decline of the last several years has been halted with a workover program on existing wellbores. The rig has moved and is now being used to drill the PMN-1116 development well in the same field.

Tags: Gran Tierra Energy Inc.