| Title | Characterization of Geothermal Reservoir Units in Northwestern Alberta by 3D Structural Geological Modelling and Rock Property Mapping |
|---|---|
| Authors | Simon N. WEIDES, Inga S. MOECK, Doug R. SCHMITT, Jacek A. MAJOROWICZ, Elahe P. ARDAKANI |
| Year | 2013 |
| Conference | Stanford Geothermal Workshop |
| Keywords | geothermal assessment study \\\\ 3D geological modeling \\\\ geostatistical mapping of rock properties \\\\ Enhanced Geothermal Systems EGS \\\\ Alberta Basin |
| Abstract | Foreland basins such as the Western Canada Sedimentary Basin (WCSB) host a variety of geoenergy resources. Often, the focus is on hydrocarbon resources but in times of discussions about climate change and environmental aspects, additional green energy resources are under examination. This study explores Paleozoic formations in the north western WCSB with regard to their usability as geothermal reservoirs. The study focuses on an area around Peace River in north – western Alberta. This research site covers an area of approx. 90 km * 70 km with a basin depth of 1.7 km to 2.4 km. Potential geothermal reservoir units are the siliciclastic Granite Wash unit, unconformably overlying the Precambrian basement, the Gilwood Sandstone member and Devonian carbonate units. A regional 3D lithostratigraphic model of the study area is developed based on well log data from about 1000 wells. Structures are interpreted from seven seismic lines with a total length of about 177 km and will be integrated into the model. This model enables us to quantify the subsurface conditions and to analyse the orientation of faults. Porosity and permeability of the Paleozoic formations is derived from data from about 10,000 core analyses and mapped with geostatistical methods to detect positive porosity and permeability domains. Formation temperatures within the Paleozoic strata are estimated by a newly calculated geothermal gradient and the reservoir depth range derived from the 3D model. The siliciclastic Granite Wash unit is presumable the most suitable horizon for geothermal development. In the south-western part of the study area its temperature is above 70 °C and the effective porosity is estimated with 10 % to 15 %. Geothermal heat could play a role as energy source for district heating. In energy intensive in-situ oil sands extraction processes geothermal heat could be used for preheating of water for steam production. This would lower the amount of natural gas used in oil sands production and reduce climate gas emissions. |