Greenpark Energy, now Dart Energy International, acquired the 74,130 acre (300 km2) Petroleum Exploration and Development License (PEDL) 159 on the border of England and Scotland in 2006 to test for potential coal bed methane prospectivity. While there were no coal mines in the PEDL area, there were 32 borehole penetrations of the Carboniferous Middle Coal Measures, with 14 of the boreholes being cored by the British Coal Board for testing. Based on original subsurface borehole and 2D seismic mapping, 6 seams of coal were mapped over an 18,530 acre (75 km2) area. The Six Foot, Nine Foot, Three Foot, Five Foot, Black Top and Seven Foot Seams are regionally correlatable and lay between 660 feet and 4590 feet beneath the surface. Each seam ranges from just under 3 feet to over 6 feet in gross thickness. Net coal ranges from zero at the unconformity truncation to over 66 feet. Using original gas content data, (265,106 m3) 935BCF of OGIIP was calculated as a potential resource target.

Greenpark Energy drilled three test coring wells at structurally shallow, moderate and deeper depths within the PEDL and analyzed the cores for gas content and saturation. Additional permeability testing was done, using various techniques, at each of these wells. A further exploration well was drilled to define the limits of the basin and a site was selected for pilot production test wells. Two horizontal wells were drilled in-seam and put on extended production tests.

As a result of the coring and testing appraisal program, Contingent Resources were certified within PEDL 159. With production tests, supported by numerical simulation models, a portion of the Contingent Resources were high-graded to Reserves. By using a managed testing program and the PRMS, costs were contained and sufficient Resources were able to be upgraded to Reserves to advance the field toward a commercial decision point.

URTeC 1581734

This content is only available via PDF.
You can access this article if you purchase or spend a download.