Study on heat conduction mechanism of hot dry rocks in deep Earth

Abstract

Hot dry rock (HDR) geothermal energy is a type of renewable energy with a great potential prospect in the deep strata. In recent years, the discovery of high-temperature HDR in Yangbajing further promotes it to be a strategic base of new geothermal resources. However, the composition, emplacement age, temperature, pressure, depth and spatiotemporal distribution of HDR are not clear, which restricts the exploration and exploitation of geothermal energy and the understanding of tectonic-thermal evolution history in this area. In this paper, a series of heat evolution processes including stratum heating up, cap-blocking heat conduction and stratum reaching stable state after being attacked by magma, is simulated. In addition, the temperature and stress field changes in HDR mining system are predicted and a series of numerical simulations are carried out. In this work, the finite element analysis method is used to simulate the conduction process of dry hot rock, mainly depending on density, Young's modulus, heat conduction coefficient, heat capacity coefficient and other parameters to establish different strata, while the boundary conditions of stress field, seepage field and temperature field are set up. The influence of fractures on HDR mining is also simulated. The purpose of this paper is to predict a series of factors affecting heat conduction of hot dry rock by numerical simulation.