Evaluating geothermal energy production from suspended oil and gas wells by using data mining

Can suspended oil and gas wells be retrofitted to generate geothermal power? This study answers this question by evaluating and indexing the geothermal potential of suspended wells completed in Western Canadian Sedimentary Basin (WCSB) and identifying the best candidates for repurposing. First, a contour map of temperature gradient (TG) distribution in WCSB is developed by utilizing temperature-log data. Second, the Ordinary Kriging geostatistical technique is applied to interpolate TG at each suspended well to verify the reported bottomhole temperature (BHT). Then, a supervised fuzzy clustering (SFC) algorithm is developed to estimate the geothermal potential of each suspended well. Finally, the geothermal power and production temperature delivered to the nearest residential areas and power grids are estimated while considering heat loss in wellbore and surface pipelines. The results show that: 1) a coaxial borehole heat exchanger with 7" diameter installed in a suspended well with BHT >= 85 degrees C at depth <= 3,000 m can deliver up to 130 KWof geothermal power at production temperature of 50 degrees C to a residential area 1 km away; 2) 50% of the heating power needed in some residential areas can be gained by retrofitting suspended wells; and 3) suspended gas wells have a relatively high potential for repurposing. (C) 2022 Elsevier Ltd. All rights reserved.