Gran Tierra Energy Inc. announced the results of a qualified independent reserve evaluation of the company's Peru reserves by GLJ Petroleum Consultants Ltd. (GLJ) effective December 31, 2013. Gran Tierra Energy has successfully booked significant reserves at the Bretaña field in Peru. On a proved plus probable (2P) and proved plus probable plus possible (3P) basis, the Bretaña field reserves nearly double the total corporate 2P and 3P reserves booked at year-end 2012.

The company currently planning on initiating long-term test production from this field beginning in September 2014, with an appraisal well planned to be drilled in the fourth quarter of 2014 in the southern portion of the Bretaña field. Furthermore, additional unbooked resource potential has been identified in an extension of the Bretaña structure on recently acquired and interpreted 2D seismic. This discovery is a dramatic reserve addition for Gran Tierra Energy, building on substantial historical success in Colombia, and is expected to provide significant growth for Gran Tierra Energy and assist Perupetro in achieving its objective to bring new oil to the market on behalf of the Government of Peru in the coming decade.

Gran Tierra Energy is scheduled to spud a water-injector well in the in the first quarter of 2014 and begin drilling the Bretaña Sur appraisal well on the southern portion of the field in the fourth quarter, 2014. Long-term test (LTT) production from the Bretaña-1ST well is anticipated to start in September of 2014 at a rate of approximately 2,500 barrels of oil per day gross. The LTT will provide valuable information on the reservoir to optimize field development, in addition to providing early cash flow.

Gran Tierra Energy's 2014 capital spending program for the Bretaña field is $107 million, consistent with the previously reported $148 million 2014 capital spending program for Peru, and includes LTT facilities, drilling a water disposal well, platform construction and drilling of an appraisal well, a Front End Engineering Design for field development, and additional related costs. The preliminary Bretaña full field development plan, based on an independent third party preliminary, front-end engineering and design study and internal estimates, contemplates $1.197 billion in future capital spending. This capital spending is associated with developing the 2P reserves over the next 11 years with peak annual capital spending of approximately $275 million expected to come in 2020.

First LTT production is expected to start September of 2014 with the next production phase expected to begin in 2017 at approximately 6,000 barrels of oil per day gross. Plateau production is expected to be initiated in approximately 2021 and continue for approximately 2 to 4 years at between 20,000 to 40,000 barrels of oil per day gross depending on ultimate definition of recoverable reserves size and reservoir performance characteristics. A new 2-D seismic program over the Bretaña field was acquired in late 2013.

This seismic program identified a structural extension of the Bretaña field which has a previously drilled well, Envidia-1, located on its flank. The Envidia-1 well had oil shows above the oil-water contact of the Bretaña field, but was not tested. The structural closure the Bretaña field oil-water contact in the south lobe containing the Envidia-1 well encompasses approximately 6,700 acres.

The resource potential of this structural extension is not included in the Bretaña field reserve assessment and offers additional upside potential for the Bretaña field development in the future.