Numerical investigation of fluid flow and heat transfer in a two dimensional anisotropic EGS model

摘要

Geothermal energy has advantages of high stability, fine continuity, and high utilization coefficient. It will become one of the most important part of energy in the future. But low-temperature geothermal resource, most of which is hydrothermal type, accounts for only 10% of the earth's geothermal energy. It has a relatively low efficiency when used for power generation. The thermal field scale is generally small which can't maintain to produce electricity steadily for a long time. Enhanced geothermal systems (EGS) which is aimed at developing and utilizing thermal energy of hot dry rock gradually arouse people's wide attention. Based on Habanero reservoir, we established a two-dimensional anisotropic model to study the effect of permeability anisotropy on EGS. With the ratio of vertical permeability to horizontal permeability as the index, the results show that when the pressure drop is not considered, the exploited geothermal energy reaches the maximum when the ratio is 0 due to the longest EGS life. It is over 2100MJ. And when the pressure drop is considered, the best ratio is about 1.3 for the net total power generation which is 20000MW.h with the optimum effect on pressure drop and EGS life.