Exploration History and Resource Assessment Summary for Devonian Strata, Liard Basin, Northeastern British Columbia – a Synopsis

Warren Walsh and Mark Hayes
British Columbia Ministry of Energy and Mines, Victoria, BC

The Liard Basin is a sub-basin of the Western Canada Sedimentary Basin which straddles the Northwest and Yukon Territories boundary with the Province of British Columbia. The basin contains over 5 km of sedimentary strata of Cambrian through Upper Cretaceous age, which can be divided into two general phases of depositional history; Cambrian through Devonian clastic and carbonate deposition along the western miogeocline and Upper Devonian through Upper Cretaceous deposition within a subsiding trough bounded to the east by the Bovie Fault system. Hydrocarbon pools have been discovered in Devonian, Carboniferous and Cretaceous strata.

Recent gas discoveries within the Devonian Nahanni Formation north of Fort Liard, NWT renewed interest in a play that had its first discovery in 1961 at the Beaver River field of Northeastern British Columbia. Originally over 1.4 Tcf of reserves were associated with this pool, however, high water to gas ratios resulting from the highly fractured reservoir and active water drive led to premature shut-in of the field.

Resource assessments for the Devonian Nahanni play indicate between approximately 2.8 and 6.6 Tcf undiscovered gas throughout the basin, with approximately 2.5 Tcf is estimated to be located within British Columbia. Advances in seismic and completion techniques are giving new life to the play north of the 60th parallel, however, only limited new activity has occurred within the northeastern British Columbian portion of the Liard Basin.

AAPG Search and Discovery Article #90039©2005 AAPG Calgary, Alberta, June 16-19, 2005