Mapping and resource evaluation of deep high-temperature geothermal resources in the Jiyang Depression, China

In China, geothermal resource utilization has mainly focused on resources at shallow and medium depths. Yet, the exploration of deep, high-temperature geothermal resources holds significant importance for achieving the "dual carbon" goals and the transition of energy structure. The Jiyang Depression in the Bohai Bay Basin has vast potential for deep, high-temperature geothermal resources. By analyzing data from 2,187 wells with temperature logs and 270 locations for temperature measurement in deep strata, we mapped the geothermal field of shallow to medium-deep layers in the Jiyang Depression using ArcGIS and predicted the temperatures of deep layers with a burial depth of 4,000 m. Through stochastic modeling and numerical simulation, a reservoir attribute parameter database for favorable deep, high-temperature geothermal areas was developed, systematically characterizing the spatial distribution of geothermal resources within a play fairway of 139.5 km2 and estimating the exploitable deep geothermal resource potential by using the heat storage method and Monte Carlo data analysis. The study reveals that the Fan 54 wellblock in the Boxing-Jijia region is of prime significance to develop deep, high-temperature geothermal resources in the Jiyang Depression. Strata from the Cenozoic to the Upper Paleozoic are identified as effective cap layers for these deep geothermal resources. The Lower Paleozoic capable of effectively storing thermal energy and possessing an exploitable resource volume up to 127 million tons of standard coal, is identified as a target system for the development of deep high-temperature geothermal resources, providing significant insights for the efficient development of geothermal resources in the Jiyang Depression.