A number of potential geothermal targets have been previously identified in the Alberta Basin (Canada). These targets were identified mainly based on temperature data collected by the oil and gas industry, which are known to be inherently biased by drilling activities and contain large measurement errors. Utilizing the vast number of measurements available from the oil and gas industry we have determined which measurements are statistically reliable in order to re-evaluate the previous temperature estimates for these anomalies, and provide a regionally accurate temperature model. Over 70% of the available measurements were removed from the temperature database based on this method, resulting in a regionally consistent database with average standard deviations of 3°C across all measurement locations.

The Alberta Basin as foreland basin of the Rocky Mountains is known for its resources of oil, gas and coal. Due to its characteristic flexure of the foreland lithosphere this basin type deepens significantly towards the orogenic belt. These foreland deeps host potentially sedimentary layers containing hot fluids and structurally or facies controlled high permeability domains. Two focus regions are studied by well data analysis, 2D seismic sections, stress field analysis and temperature modeling. The study areas are located around the city of Edmonton in central Alberta (basin depth 1.8 – 3.5km) and in northeastern Alberta around the town of Peace River (basin depth 1.7 – 2.4 km). Extension and thickness of potential geothermal target formations is investigated by 3D structural geological modeling, and geostatistical methods are applied to analyze the distribution of porosity, permeability and temperature within these formations. For central Alberta, the medium to coarse grained Cambrian Basal Sandstone Unit is the most promising formation for deep geothermal applications. This potential hydrothermal resource could be used for district heating in the Edmonton metropolitan area, where the Cambrian Sandstone is located at a depth of 2.2 – 2.7km with a temperature of 78 – 93°C. Fluids from overlying Upper Devonian porous carbonates host fluids up to 63°C. In northeastern Alberta, warm fluids (51-75°C) from the siliciclastic Granite Wash Unit could be used for heating of greenhouses. Considering the climatic conditions in Alberta with its long and cold winter season, the temperature range between 60-90°C of hydrothermal resources seems to be efficient in highly populated areas with high heat demand as the metropolitan region of Edmonton, remote areas on northern Canada where fuel for heating needs to be transported by helicopters, or generally in Canada to grow local food in greenhouses.

Recent geothermal exploration indicated that the Cambrian Basal Sandstone Unit (BSU) in central Alberta could be a potential target formation for geothermal heat production, due to its depth and extent. Although several studies showed that the BSU in the shallower Western Canada Sedimentary Basin (WCSB) has good reservoir properties, almost no information exists from the deeper WCSB. This study investigated the petrography of the BSU in central Alberta with help of drill cores and thin sections from six wells. Porosity and permeability as important reservoir parameters for geothermal utilization were determined by core testing. The average porosity and permeability of the BSU is 10% and <1 × 10−14 m2, respectively. A zone of high porosity and permeability was identified in a well located in the northern part of the study area. This study presents the first published geomechanical tests of the BSU, which were obtained as input parameters for the simulation of hydraulic stimulation treatments. The BSU has a relatively high unconfined compressive strength (up to 97.7 MPa), high cohesion (up to 69.8 MPa), and a remarkably high friction coefficient (up to 1.22), despite a rather low tensile strength (<5 MPa). An average geothermal gradient of 35.6 °C/km was calculated from about 2000 temperature values. The temperature in the BSU ranges from 65 to 120 °C. Results of this study confirm that the BSU is a potential geothermal target formation, though hydraulic stimulation treatments are required to increase the permeability of the reservoir.

This study explores the siliciclastic Granite Wash Unit in northwestern Alberta as a potential geothermal reservoir. The approach covers regional 3D structural geological modelling of a 90 km × 70 km area based on well log and legacy 2D seismic data. The fault strike was interpreted from lineaments, which were identified with the refined trend surface analysis method. The stress state of the Granite Wash reservoirs was determined by an integrated approach of 3D fault modelling, stress ratio definition based on frictional constraints, and slip tendency analysis. The results show that the best site for a geothermal application is located in the southwestern study area, where the highest temperatures (above 70 °C) coincide with the largest thickness (above 20 m) and zones of elevated porosity and permeability. The integrated stress analysis indicates an in situ stress regime from normal to strike-slip faulting maintaining a non-critically stressed reservoir or faults therein, assuming a friction coefficient of 0.7. The granite wash reservoirs could be used for heating of greenhouses, domestic warm water provision and district heating.

The province of Alberta has a high demand of thermal energy for both industrial and residential applications. Currently, the vast majority of the heat used in these applications is obtained by burning natural gas. Geothermal energy production from deep aquifer systems in the sedimentary basin could provide an alternative sustainable source of heat that would significantly reduce greenhouse gas emissions.To date there has been no geothermal field development in Alberta because the average geothermal gradient was considered to be too low for economic geothermal energy generation. However, with new technologies for Enhanced Geothermal Systems (EGS), it may be possible to develop geothermal resources from the sedimentary rocks in the Western Canadian Sedimentary Basin (WCSB). A numerical feasibility study based on a regional geological model and existing and newly gained data was conducted to identify scenarios for geothermal energy production in the region.In central Alberta, three Devonian carbonate formations (Cooking Lake, Nisku, Wabamun) and the Cambrian Basal Sandstone Unit were identified as the highest geothermal potential zones. Thermal-hydraulic reservoir simulations for a 5 km x 5 km site in the city of Edmonton were performed to evaluate reservoir development concepts for these four potential target formations: therefore, hydraulic fracturing treatments were also simulated. Different utilization concepts are presented for possible applications of geothermal energy generation in residential, industrial and agricultural areas.The Cooking Lake formation and the Basal Sandstone Unit are potentially the most promising reservoirs because the most heat can be extracted and the applications for the heat are widespread although the costs are higher than utilizing the shallower formations. Reservoir stimulation considerably improves the economics in all formations. (C) 2014 Elsevier Ltd. All rights reserved.

Heat flow and geothermal gradient of the sedimentary succession of the Western Canada Sedimentary Basin (WCSB) are mapped based on a large thermal database. Heat flow in the deep part of the basin varies from 30 mW/m2 in the south to high 100 mW/m2 in the north. As permeable strata are required for a successful geothermal application, the most important aquifers are discussed and evaluated. Regional temperature distribution within different aquifers is mapped for the first time, enabling a delineation of the most promising areas based on thermal field and aquifer properties. Results of previous regional studies on the geothermal potential of the WCSB are newly evaluated and discussed. In parts of the WCSB temperatures as high as 100–210 °C exist at depths of 3–5 km. Fluids from deep aquifers in these “hot” regions of the WCSB could be used in geothermal power plants to produce electricity. The geothermal resources of the shallower parts of the WCSB (>2 km) could be used for warm water provision (>50 °C) or district heating (>70 °C) in urban areas.

Heat flow (Q) determined from bottom-hole temperatures measured in oil and gas wells in Alberta show a large scatter with values ranging from 40 to 90 mW m−2. Only two precise measurements of heat flow were previously reported in Alberta, and were made more than half a century ago. These were made in wells located near Edmonton, Alberta, and penetrated the upper kilometre of clastic sedimentary ro...

The province of Alberta has a high demand of thermal energy for both industrial and residential applications. Currently, the vast majority of the heat used in these applications is obtained by burning natural gas. Geothermal energy production from deep aquifer systems in the sedimentary basin could provide an alternative source of heat that would be both sustainable and help Alberta reduce greenhouse gas emissions. To date there has been no geothermal field development in Alberta because the average geothermal gradient of 30 °C/km was considered to be too low for economic geothermal energy generation. However, with technologies for Enhanced Geothermal Systems (EGS), it may be possible to develop geothermal resources from the sedimentary rocks in the Alberta Basin. A feasibility study based on existing and newly gained data is necessary to identify scenarios for geothermal energy production in the region. In this paper, we investigate the potential of these geothermal energy systems by geological modeling and reservoir simulation in terms of EGS. Geological modeling enables us to map and quantify the subsurface conditions and delineate thermal resources. Reservoir simulation is then used to identify the potential productivity of thermal energy. A regional scale geological model of the Central Alberta Basin has been developed for an area around Edmonton with a horizontal extent of 200 km x 160 km (Weides et al., in press). This model is based on stratigraphic data from about 7000 wells and includes all major formations from the surface to the Precambrian basement. In Central Alberta, four Devonian carbonate formations and the Cambrian Basal Sandstone Unit are identified as the highest geothermal potential zones. Four formations were selected for more detailed investigations; thermal, hydraulic, and mechanical properties of these formations are obtained from geological databases, literature, and from new laboratory measurements. Finally, thermal-hydraulic reservoir simulations for a 5 km x 5 km site in the city of Edmonton were performed to evaluate reservoir development concepts. Hydraulic fracturing treatments are simulated for the various geological formations. Different utilization concepts are presented for possible applications of geothermal energy generation in residential, industrial and agricultural areas.

Foreland basins as the Alberta Basin in Canada 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 requested. This study explores Paleozoic formations in the north western Alberta Basin with regard to their usability as geothermal reservoirs. A 3D geological model is developed based on 177 km of 2D seismic data and stratigraphic picks of about 1000 wells from the Alberta general well data file. Seven siliciclastic and carbonate units form the major Paleozoic aquifer systems. Porosity and permeability of these Paleozoic formations is derived from data from about 10,000 core analyses and mapped with geostatistical methods. Formation temperature of Paleozoic strata is 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 potential horizon suitable for geothermal development. Its temperature is above 70 °C, effective porosity is estimated with 10 % to 15 %. A possible application for the production of geothermal heat is the provision of warm water for in-situ oil sands extraction in this region reducing climate gas emissions.

This study explores the distribution of Paleozoic formations in the Central Alberta Basin and investigates rock properties with regard to their usability as geothermal reservoirs. The study area of this regional-scale investigation is about 160 km × 200 km in size and located around Edmonton where the basin depth ranges between 1.8 and 3.5 km. A three-dimensional (3D) geological model was developed based on stratigraphic tops from about 7000 wells from the database of the Alberta Geological Survey (AGS). Spatial distribution and thickness of deep formations were established in the 3D geological model. Porosity and permeability of four Devonian carbonate formations — Cooking Lake, Leduc, and Nisku formations, and Wabamun Group — were investigated using data from more than 50 000 core analyses. Average porosity of the Devonian strata in the study area ranges from 4.5% (Nisku) to 8.7% (Wabamun), average permeability is between 3.5 × 10−15m2(Wabamun) and 26 × 10−15m2(Leduc). The distribution of both parameters was analyzed using geostatistical methods. Based on an average geothermal gradient and the geometry of formations from the 3D modeling study, an estimation of formation temperatures for the Paleozoic formations is presented. Temperature in the Cambrian Basal Sandstone Unit ranges from 62 °C in the shallower northeast (1.8 km) to 122 °C in the deeper southwest (3.5 km); temperature in the Devonian strata ranges from 22 to 87 °C. With these new results, potential geothermal reservoirs can be delineated in the Alberta Basin around Edmonton, enabling future detailed exploration and field development.

•Athabasca oilsands : Temperatures > 60°C will only be found in Precambrian basement (granite) at depth in excess of 3km. Heat needed for extraction and processing. Calculations considered the thermal output of an EGS doublet system producing water at 100°C and included energy needed to operate pumps. This system produces net energy when the flow rate is greater than >30l /s. The financial cost is comparable with the cost of burning natural gas if flow rates are greater than 50llitres per second and if the system operates for at least 30 years. 100 EGS doublets drawing water at 100oC from wells in the deep sedimentary basin or granitic basement could save >3MT of CO2 per year. Current oilsands operations generate 40MT of CO2 per year. Introduction

An adequate comprehensive understanding of the subsurface geology is a pre-requisite for a precise planning and successful operating of geothermal applications and reduces the financial risks considerably. An exploration concept is needed which is tailored for the geological setting to be evaluated and the level of exploration performed prior to the geothermal exploration. We present examples from ongoing geothermal exploration projects encompassing, for example, studies on the geological structure, including the stress field, on the hydraulic and thermal properties of geological formations, and on the temperature prognoses for target reservoirs.

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.