Gran Tierra Confirms Oil Find at Putumayo Basin

Gran Tierra had completed initial testing of the Moqueta-1 exploration well, a new field discovery on the Chaza Block in the Putumayo Basin, Colombia, while preparations to drill the Moqueta-2 appraisal well are under way. Gran Tierra Energy has a 100% working interest and is the Operator of the Chaza Block.

"The successful discovery of oil with the first well in Gran Tierra's 2010 exploration program further reinforces the strength of our exploration portfolio," said Dana Coffield, President and Chief Executive Officer of Gran Tierra. "We are preparing to drill a second well and initiate a 3-D seismic acquisition survey in the area to give us further information on the size and productive capacity of the new discovery. Finally, planning to initiate long term testing has begun, with early production anticipated in the first quarter of 2011."


Gran Tierra has completed initial testing on Moqueta-1 by collecting reservoir data and fluid samples from two zones - the lower Caballos Formation and the Villeta T Sandstone. The Caballos Formation has 53 feet of total hydrocarbon pay, subdivided into 27 feet of net gas pay in the Upper Caballos and 26 feet of net oil pay in the Lower Caballos. A 20 foot net (39 feet gross) interval, in the lower portion of the lower Caballos oil bearing interval was tested and perforated from 3,950 feet to 3,970 feet measured depth. A variety of tests were performed resulting in natural flow rates, without pumps, of up to 349 barrels of oil per day with a 32/64 inch choke and a 0.2% watercut with 29 degrees API gravity oil.

In the Villeta T Sandstone, a short 12 foot (3,734 feet to 3,746 feet measured depth) interval of the 55 feet of net gas pay was perforated and tested at 13 million standard cubic feet per day using a 48/64 inch choke size. No additional gas testing was conducted in the T Sandstone in order to preserve the casing integrity for future oil production from the Lower Caballos.

Appraisal Plan

Planning is underway to construct an 8 kilometer pipeline to tie Moqueta-1 into the Costayaco infrastructure, with anticipated initiation of long term oil testing and early production in the first quarter of 2011.

The drilling rig is currently being mobilized to drill Moqueta-2, an appraisal well to be drilled from the existing Moqueta-1 pad. The bottom-hole location is planned to be approximately 270 meters east of the Moqueta-1 bottom-hole location. The objective is to delineate the volume of the lower Caballos oil pool by targeting the reservoir approximately 60 feet deeper down the flank of the structure. Moqueta-2 will also test the potential for a gas/oil contact in the Villeta U, Villeta T and upper Caballos zones down structure.

Pending results from Moqueta-2, Moqueta-3 would be drilled from a new pad location approximately 1.5 kilometers southwest of the Moqueta-1 surface location.

A 230 square kilometer 3D seismic survey is scheduled to be conducted to cover the Moqueta discovery and adjacent prospects and leads. This survey will overlap existing 3D surveys that cover the Costayaco Field in the Chaza Block; the Juanambu, Toroyaco, Linda, Mary, and Miraflor Fields in the adjacent Gran Tierra operated Santana and Guayuyaco Blocks; as well as the upcoming Verdeyaco 3D survey on the Chaza and Guayuyaco Blocks.