Imaging near-surface thermal anomalies for cost-effective detection of hidden geothermal resources: A case study in Shanxi province, North China

Geothermal energy is an environmentally friendly alternative energy source, but its widespread and large-scale utilization is limited by the high cost and risk for exploring and developing new areas. Conventional exploration methods face major challenges in detecting ground fluid and heat assemblage, highlighting the need for more efficient and economical geothermal exploration technologies. This paper proposes a method for detecting hidden geothermal resources by focusing on near-surface thermal anomalies. The temperature was measured over a 20 square kilometer area, which included 60 wells ranging in depth from 50 to 200 m The normalized temperature contour maps were drawn to delineate two distinct geothermal sweet spots: the western and eastern anomaly areas, which have maximum anomaly amplitudes of 100 % and 30 %, respectively. Geothermal resources in the western areas were confirmed through drilling, which produced hot water at 50 °C and a flow rate of 40 L/h from an 800-meter deep basement reservoir. The slight thermal anomaly in the eastern area is likely due to the Urban Heat Island effect rather than deep heat. These findings demonstrate the potential of using near-surface thermal anomalies for efficient and economical geothermal exploration and for studying the urban heat island effect on the surrounding underground thermal environment.