A FAVOURABILITY ASSESSMENT OF GEOTHERMAL ENERGY POTENTIAL IN NORTHEASTERN BRITISH COLUMBIA, CANADA

The majority of research around geothermal energy in Canada has focused on high temperature volcanic environments. The lower temperature resource of the warm sedimentary basin in northeastern British Columbia has been studied to a lesser extent. However, substantial amounts of data from oil and gas developments allow us to assess the geothermal potential of this region. The oil and gas records contain temperature, production and flow tests that indicate the availability of water at depth. Data is filtered to include data of Devonian age only, where temperature mapping indicates that aquifers, warm enough to potentially produce electricity, exist.

A favourability map is created using a geographic information system. This allows us to identify the most favourable sites warranting a site-specific assessment of the resource at a later stage. First, we compile a temperature grid; not at a fixed depth, but from middle Devonian strata of the Elk-Point Group. This approach allows us to assess only those strata that potentially contain aquifers. A constant depth temperature map would contain strata from several different periods, since the basin becomes shallower as we move away from the Rocky Mountain range. Aquifers are identified by water production and permeability indicators. Both indicators are extracted from a) drill stem test logs executed on wells drilled for hydrocarbons and b) water production associated with natural gas producing fields.

Apart from geological data, we take additional factors such as the distance to electrical transmission lines and substations into account. Further, population centers and shale gas development areas are included for their potential electrical and heat loads. Ultimately, a favourability score is calculated at each grid point in the study area, where each contributing factor is weighted via the Analytical Hierarchy Process. This methodology allows us to compare the inherently different factors on a congruent scale.

The resulting map of scores shows the favourability of developing a geothermal power plant at each point on the grid of the study area. Several locations indicate favourable scores. The map allows us to select the most promising locations for a site-specific assessment of resource potential and financial viability to be performed in future work.