Numerical simulation of seismic wave in deep geothermal rock mass

Key words:  deep geothermal rock  seismic wave propagation mechanism  numerical simulation  finite difference modeling

Abstract:

Deep geothermal resources represent a substantial form of renewable and clean energy.However, their geophysical response characteristics remain poorly understood, leading to a low success rate in exploring these resources. This study aims to investigate the propagation theory and wavefield characteristics of seismic waves within deep geothermal rock masses. To achieve this, two deep geothermal granite models were established, and numerical simulations of acoustic and elastic waves were implemented using the equivalent staggered grid finite difference method. The numerical simulation results reveal that the velocity of geothermal granite is much higher than that of surrounding rock due to temperature influences, which results in a phenomenon known as high-speed shielding and weakens the transmitted wave energy, consequently limiting the propagation of seismic waves within the lower part of the geothermal rock mass. In addition, compared with acoustic waves, elastic waves offer richer information about the wavefield. The conversion of wave mode and energy makes seismic records of elastic waves more complex than acoustic waves.