Testing results are expected in approximately one month.Sierra Nevada Block (Gran Tierra Energy 100% WI and Operator) Drilling of the Brillante SE-2 delineation well is expected to begin late October, 2011. This gas field was discovered in 2010 and lies in the Lower Magdalena Basin in northern Colombia. This is the first of two delineation wells that are planned to be drilled in late 2011 and early 2012, with the intent to define adequate reserves to justify the construction of a gas pipeline and commit to long term gas sales contracts. The field is currently producing a nominal volume of gas which is transported by a third party utilizing compressed natural gas trucks. Gran Tierra Energy plans to increase this production to approximately 2 million standard cubic feet of gas per day before the end of 2011. The well is expected to reach total measured depth of approximately 6,000 feet and take approximately 25 days to drill. Garibay Block (CEPSA 50% WI and Operator, Gran Tierra Energy 50% WI) Drilling of the Jilguero-2 delineation well in the 2010 Jilguero oil discovery in the Llanos Basin of eastern Colombia is ahead of schedule. The well is expected to reach total measured depth of approximately 9,830 feet in mid-October. Planning for the initiation of long-term testing of Melero-1, a new oil discovery made in 2011, is continuing, with first production expected in December. "In summary, the Fourth Quarter of 2011 is going to be a very exciting time for our company, with exploration, delineation and development drilling results expected in Brazil and Colombia, and planning ongoing for a robust 2012 drilling program in those countries as well as in Peru and Argentina, all expected to be fully funded with cash and cash flow at current oil prices and production volumes," concluded Coffield. About Gran Tierra Energy Inc. Gran Tierra Energy is an international oil and gas exploration and production company, headquartered in Calgary, Canada, incorporated in the United States, trading on the NYSE Amex Exchange (GTE) and the Toronto Stock Exchange (GTE), and operating in South America. Gran Tierra Energy holds interests in producing and prospective properties in Colombia, Argentina, 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. 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 the words "expected", "planned", "plans", "scheduled", "may", "will" and derivations thereof similar terms identify forward-looking statements. In particular, but without limiting the foregoing, this news release contains forward-looking statements regarding Gran Tierra Energy's planned and expected drilling operations in Brazil and Colombia including, without limitation: anticipated drilling locations, depths and timelines; the results of Gran Tierra Energy's two farm-in agreements with Statoil; expectations respecting testing, pilot hole and delineation drilling; the timing and amount of production expected from drilling activities; and the funding of drilling and operations. 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; that Gran Tierra Energy will continue to conduct its operations in a manner consistent with past operations, the accuracy of testing and production results and seismic data, the effects of certain drilling techniques and the general continuance of current or, where applicable, assumed operational, regulatory 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.