An integrated 3D method to assess the application potential of GWHP systems in fluvial deposit areas

Abstract

Fluvial deposits are commonly abundant in groundwater resources, indicating very high potential for the application of groundwater heat pump (GWHP) systems. To better understand the geospatial variation in geothermal potential, this paper presents a multidisciplinary 3D approach to assess aquifer-based geothermal resources in the Han River area in Hubei Province, China. The geological setting was determined by collecting data from 1286 drilling holes. The thermophysical-hydraulic properties were investigated, and the geospatial variation was characterized by 3D geological modeling. A GIS-based procedure was deployed for the assessment of the geothermal potential by extracting parameters from these 3D models as input. The results show that the middle reaches have the highest potential due to the great thickness of the aquifer layers, followed by the upper reaches, and the lower reaches have the lowest potential. The validation of 3 specific cases, located in the upper, middle, and lower reaches, shows that the model has uncertainties of 6.1%, 14.7% and 5.5%, respectively. This implies that the accuracy of the estimated potential depends on both the available drilling data and geological heterogeneity. This study shows that integrated 3D modeling and the GIS-based approach could be useful in geothermal planning in fluvial deposit areas.