The Corbett Coalbed Methane Pilot Project: Untapping a Potential Giant

Simpson, Mike, Nexen Inc, Calgary, AB

Coal bed methane (CBM) in Western Canada has been called the “largest untapped gas opportunity in North America” with gas-in-place estimates as high as 600 Tcf. The Alberta Geological Survey estimates that approximately 50% of that gas resource may be contained in Upper Mannville coals seams. Despite this huge resource potential, no commercial devel­opment has yet occurred on this play.

The Corbett Upper Mannville CBM pilot project (operated by Trident Exploration Corp.) was initiated in late 2001 and is the largest and longest running pilot project on this play. More than 50 vertical and horizontal pilot wells have been drilled to-date. There have been four phases of pilot expansion since the original pilot commenced production in early 2002. Yet it is only recently that the some of the pilot wells have started to yield commercial pro­duction rates.

The Upper Mannville CBM play covers an area of approximately 50,000 square kilome­tres. Gas content, coal rank, depth, coal distribution, permeability, and structural setting are the key technical factors that control how much of the play will ultimately be developed and turned into reserves. The Corbett pilot project is optimally located in an area with high gas content, moderate depth, attractive coal seam thickness and continuity, and good permeabil­ity as demonstrated by the water production rates possibly related to post-coal deposition faulting. The greater Corbett area is estimated to contain in excess of four Tcf gas-in-place with an expected economically recoverable reserve potential greater than one Tcf – a poten­tial national class giant.