GEOTHERMAL MAPPING IN ALBERTA - A STATISTICALLY ROBUST APPROACH

Extensive oil and gas development in the Western Canada Sedimentary Basin (WCSB) of Alberta has resulted in a large amount of well data and core samples which can be utilized for detailed geothermal characterization of the subsurface. One approach to geothermal exploration in a sedimentary basin is to map the surface heat flow, which can facilitate identification of favourable regions for geothermal energy development. In order to determine the surface heat flow in Alberta, we have compiled a dataset which is more comprehensive and robust than ever before, including more types of temperature data which have been filtered to see the regional scale variations, and a thermal conductivity model which includes more lithology information than previously. This dataset has resulted in a new heat flow map of Alberta giving a more accurate than ever before regional estimate of the heat flow in Alberta.

The temperature data available from the oil and gas industry has long been recognized to contain significant error and systematic bias. In order to develop a reliable database of temperature measurements, systematically biased data have been manually removed, and the remaining random errors were removed using a statistical data re-sampling method.

The thermal conductivity model is based on using the lithology known from a number of wells in the basin, and assigning appropriate thermal conductivity values to each lithology. The thermal conductivity in part explains some of the thermal anomalies in the temperature data, although spatial variation in heat flow from below also significantly affects spatial variations in temperature. With this new set of data, temperature anomalies are better understood, facilitating geothermal prospecting and allowing for a more robust study of the relationship between Precambrian terrane boundaries and heat flow.