Thermal‐Hydraulic‐Mechanical Modelling for Natural Convection Within High Permeability Carbonate Formations in Xiong'an Area

The temperature field in the high permeability carbonate geothermal reservoir is poorly constrained. The numerical simulation provides a powerful tool to reveal the characteristics and mechanism of heat transfer in the carbonate reservoir. Xiong'an New District, 140 km south of Beijing, China, is a typical and large‐scale carbonate formation developed area. In this study, based on the geothermal measurement data, a two‐dimensional thermal‐hydraulic‐mechanical numerical simulation was conducted to analyse the genetic mechanism of the carbonate formation temperature. Sensitivity of formation temperature to the key parameters of the reservoir and their heterogeneities was also tested. The unique thermophysical parameters of the reservoir, characterised by high permeability and thermal conductivity, are the crucial reasons for the uniform temperature distribution of the carbonate formation. Influence of basement uplift, water‐conducting fractures, and heterogeneous permeability on the geothermal distribution was also analysed. The thermal refraction effect caused by basement uplift, groundwater activity due to water‐conducting fractures, and the abnormally high permeability of carbonate rocks are the main causes of thermal anomalies in the study area. As the ratio between horizontal and vertical permeability increases, the groundwater activity within the rock layers becomes weaker, and the thermal convection effect generated has a gradually decreasing impact on the geothermal distribution.