VOLUMETRIC ASSESSEMENTS OF GEOTHERMAL POWER POTENTIAL FROM DEVONIAN STATA IN THE WESTERN CANADIAN SEDIMENTARY BASIN

Geotechnical and hydrogeological data from well bore logs and rock cores were used to identify, map, and model the power production potential of geothermal reservoirs in sedimentary formations in the Western Canadian Sedimentary Basin, across several Municipal Districts in western Alberta. We show a general workflow for using oil and gas data to assess geothermal resources in sedimentary basins, present a series of contour maps and stratigraphic grids of salient geothermal reservoir properties and assess the power production potential of these resources using a volumetric (heat-in place) method.

More than 65,000 different wells were analyzed in order to locate hot, potentially water-bearing strata in the west-central parts of Alberta. We identified and quantified the geothermal resource potential of two middle Devonian carbonate reefs and two early to middle Devonian sandstones. We mapped the regional distribution of surface top depth, temperature, formation thickness, potentiometric surfaces and porosity for each of the formations.

Well data was used to construct 3-D stratigraphic grids of these formations underlying population centers in western Alberta. Formations volumes calculated from these stratigraphic grids were used to calculate the power production potential of the formations using the heat-in-place method. In total, throughout the study area, we identified a potential thermal power capacity of ~6,100 MWt per for a 30-year production period, of which 80% was located within carbonate reservoirs and 20% within sandstone reservoirs. Reservoir depths ranged from about 2500 m to over 5000 m. Formation temperatures ranged from ~60 °C to over 150 °C. The calculated thermal power capacity equates to ~1,150 MWe of potential electrical power capacity over the 30 year production period, of which ~ 800 MWe are considered high grade (>120 °C) resources that may reliably produce electricity with existing technology.