Detection and Analysis of Wrench Fault Systems and Related Hydrothermal Dolomite (HTD) Reservoirs in the Western Canada Sedimentary Basin (WCSB)

Zeev Berger¹ and Graham Davies^2
1 Image Interpretation Technologies, Calgary, AB
² GDGC Ltd, Calgary, AB

Recent HTD reservoir discoveries in the Western Canada Sedimentary Basin (WCSB) and the Central Appalachian Basin (Trenton-Black River) have sparked renewed interest for exploration in the Paleozoic section of several mature basins in North America. Current understanding of the HTD phenomenon suggests that many reservoirs in the WCSB appear to be spatially and genetically related to the presence of deep-seated, basement-involved wrench fault systems.

Lately, exploration for HTD reservoir trends in the WCSB have benefited from the use of high-resolution aeromagnetic (HRAM) data. HRAM data is commonly used in conjunction with regional seismic and well data to identify major basement-involved fault and fracture systems, define their timing and style of deformation, as well as assess their influence on the distribution of HTD reservoirs. The control basement faulting has on HTD development can be best demonstrated with examples from several gas pools in the WCSB: 1) Simonette (Middle Devonian Swan Hills and Late Devonian Wabamun); 2) Ladyfern (Middle Devonian Slave Point); and 3) Parkland (Late Devonian Wabamun). In each of these cases, it is possible to demonstrate that, 1) regional wrench fault systems correlate well with faults identified over the field with 3D seismic; and 2) most prolific wells within the pools are located along or at the intersection of fault-line traces.

A good understanding of the tectonic framework of any sedimentary basin is critical for successful exploration of HTD reservoirs.

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