Numerical modeling of 2-D conductive heat transfer and its application for the characterization of geothermal systems

Abstract

A geothermal system is basically a system where heat is transferred from the internal part to the surface of the earth dominantly by conduction, convection, or both. The spatial variation of the magnitude of conductive heat transfer represented by lateral variation of observed surface heat flow values is heavily related to the subsurface temperature distribution, the pattern of which is directly controlled by the variation of rock thermal conductivity values. Therefore, the information about subsurface temperature distribution may provide insight for the interpretation of the thermal structure of a region, within a more regional framework of geothermal systems in particular. In this research, we performed a numerical forward modeling procedure of 2-D conductive heat transfer using finite difference solution of the steady state heat conduction equation via a Gauss-Seidel scheme. The main physical parameters used as the input in the modeling procedure are rock thermal conductivity values as well as temperature boundary conditions. The modeling scheme was applied on two different synthetic common geothermal system geometries, one within a volcanic setting and one within a sedimentary environment, by using appropriate thermal conductivities and temperature boundary conditions for the assumed lithologies within each respective setting. The results of the modeling procedure were able to effectively characterize the thermal structure and surface heat flow patterns of the geothermal system in both environments.