Gran Tierra Energy Provides South America Drilling Operations Update

Ramiriqui-1 Exploration Well Encounters Oil Shows, Testing to begin in April

CALGARY, Feb. 21, 2012 /PRNewswire/ - Gran Tierra Energy Inc. (NYSEAMEX: GTE; TSX: GTE) ("Gran Tierra Energy"), a company focused on oil and gas exploration and production in South America, today announced a drilling update in the Putumayo and Llanos basins of Colombia, Recôncavo Basin of Brazil, and Noroeste Basin of Argentina.

"Gran Tierra Energy's 2012 drilling campaign is now well underway, with a mix of exploration and development drilling in both Colombia and Brazil in progress, while planning continues for additional drilling through the year in those countries, and in Peru and Argentina," said Dana Coffield, President and CEO of Gran Tierra Energy.

Colombia

Llanos-22 Block, Llanos Basin (45% working interest, subject to ANH approval; CEPSA 55% working interest and operator)

Drilling operations continue on the Ramiriqui-1 exploration well in the Llanos-22 Block in the foothills of the Llanos Basin. The Mirador formation has been interpreted as oil bearing with up to 130 feet measured depth ("MD") gross thickness based on cuttings and logging while drilling. Casing is being set.  Upon completion, drilling is expected to continue to evaluate deeper potential reservoir intervals and is expected to finish in March. Gran Tierra Energy expects testing of the Mirador formation, to confirm fluid content and reservoir productivity, to commence in April 2012.

Chaza Block, Putumayo Basin (100% working interest and operator)

The Pacayaco-1ST1 exploration well reached total true vertical depth of 5,343 feet.  Approximately ten feet of oil column in the T-Sandstone was interpreted from cuttings and evaluation of wireline logs. It was determined that the formation did not contain economic quantities of hydrocarbons so the well was plugged and abandoned.

Civil work has been initiated for the Moqueta-7 development well location, with the initiation of drilling anticipated in June 2012.

Azar Block, Putumayo Basin (40% working interest and operator)

Gran Tierra Energy is targeting the same reservoir intervals seen in the Costayaco and Moqueta oil fields with the La Vega Este-1 exploration well. Due to environmental permit delays, we have requested an extension from the ANH for this current phase; this request is still under ANH review. We expect to begin drilling the La Vega Este-1 well in April 2012.

Brazil

REC-T-142 Block, Recôncavo Basin (Gran Tierra Energy 70% working interest and operator)

Gran Tierra Energy expects drilling of the 1-GTE-6-BA oil exploration well to begin in July 2012. This operation will commence with the drilling of a vertical pilot hole from which core samples will be acquired from the prospective reservoir section. Including the already drilled 1-GTE-01-BA oil exploration well, this is expected to be the second vertical pilot hole drilled on the REC-T-142 Block.

Gran Tierra Energy plans to drill a horizontal sidetrack from each of the pilot holes to test the productivity of the light oil sandstone reservoir target beginning with 1-GTE-1-BA in April 2012.

REC-T-129 Block, Recôncavo Basin (Gran Tierra Energy 70% working interest and operator)

Drilling of the 1-GTE-02-BA oil exploration well began on November 23, 2011.  The well reached total depth of approximately 6412 feet measured depth and is suspended while plans are finalized for drilling a horizontal leg in mid 2012.

REC-T-155 Block, Recôncavo Basin (Gran Tierra Energy 70% working interest and operator)

Gran Tierra Energy expects drilling of the 1-GTE-5-BA oil exploration well to begin in June 2012. The well is located in Block REC-T-155 in the Recôncavo Basin. Similar to the vertical pilot holes drilled on the REC-T-142 Block, Gran Tierra Energy expects to drill a horizontal sidetrack well following the pilot hole to test the productivity of the reservoir sandstones.

Gran Tierra Energy completed drilling of the 3-GTE-03-BA development well which is situated 1.2 kilometers north-northeast of the 1-ALV-2-BA discovery well. Oil bearing reservoir intervals in the Sergi and Agua Grande formations were encountered and plans are moving forward to complete the well and place the well on production in May. A second development well located approximately 0.7 kilometers south-southwest of the 1-ALV-2-BA discovery well began drilling on January 8, 2012.  The well operations are currently ongoing at 3-GTE-4-BA. No further development wells are planned on this discovery at this time.

Argentina

Surubi Block, Noroeste Basin (85% working interest and operator)

Drilling continues on the Proa-2 development well in the Proa oil field in the Noroeste Basin of northern Argentina.  Gran Tierra Energy expects drilling to be completed in March, with testing and tie-in to existing facilities expected to follow in April.

About Gran Tierra Energy Inc.

Gran Tierra Energy Inc. is an international oil and gas exploration and production company, headquartered in Calgary, Canada, incorporated in the United States, trading on the NYSE Amex (GTE) and the Toronto Stock Exchange (GTE), and operating in South America. Gran Tierra Energy holds interests in producing and prospective properties in Argentina, Colombia, Peru and Brazil. Gran Tierra Energy has a strategy that focuses on establishing a portfolio of producing properties, plus production enhancement and exploration opportunities to provide a base for future growth.

Gran Tierra Energy's Securities and Exchange Commission filings are available on a web site maintained by the Securities and Exchange Commission at http://www.sec.gov and on SEDAR at http://www.sedar.com.

Advisories and Forward Looking Statements:

This news release contains certain forward-looking information and forward-looking statements (collectively, "forward-looking statements") under the meaning of applicable securities laws, including Canadian Securities Administrators' National Instrument 51-102 - Continuous Disclosure Obligations and the United States Private Securities Litigation Reform Act of 1995. The use of words such as "expects", "expected," "plans", "planned" and "will" identify these forward-looking statements. In particular, but without limiting the foregoing, this news release contains forward-looking statements regarding the expected timing of commencement and completion of drilling operations, testing and tie-in to facilities, and plans to complete 3-GTE-03-BA.

The forward-looking statements contained in this news release reflect several material factors and expectations and assumptions of Gran Tierra Energy including, without limitation, assumptions relating to log evaluations, the accuracy of certain testing results and seismic data, that Gran Tierra Energy will continue to conduct its operations in a manner consistent with past operations and the general continuance of current or, where applicable, assumed operational and industry conditions. Gran Tierra Energy believes the material factors, expectations and assumptions reflected in the forward-looking statements are reasonable at this time but no assurance can be given that these factors, expectations and assumptions will prove to be correct.

The forward-looking statements contained in this news release are subject to risks, uncertainties and other factors that could cause actual results or outcomes to differ materially from those contemplated by the forward-looking statements, including, among others: Gran Tierra Energy's operations are located in South America, and unexpected problems can arise due to guerilla activity, technical difficulties and operational difficulties which impact or delay its testing and drilling operations; geographic, political and weather conditions can impede testing and drilling operations; and the risk that current global economic and credit market conditions may impact oil prices and oil consumption more than Gran Tierra Energy currently predicts, which could cause Gran Tierra Energy to modify its exploration, drilling and/or construction activities. Further information on potential factors that could affect Gran Tierra Energy are included in risks detailed from time to time in Gran Tierra Energy's Securities and Exchange Commission filings, including, without limitation, under the caption "Risk Factors" in Gran Tierra Energy's Quarterly Report on Form 10-Q filed November 8, 2011. These filings are available on a Web site maintained by the Securities and Exchange Commission at http://www.sec.gov and on SEDAR at www.sedar.com.  The forward-looking statements contained herein are expressly qualified in their entirety by this cautionary statement. The forward-looking statements included in this press release are made as of the date of this press release and Gran Tierra Energy disclaims any intention or obligation to update or revise any forward-looking statements, whether as a result of new information, future events or otherwise, except as expressly required by applicable securities legislation.

SOURCE Gran Tierra Energy Inc.