Effect of reservoir properties on the heat extraction performance in multi-well production EGS

ABSTRACT A multi-well production enhanced geothermal system (EGS) with discrete fracture network is designed for heat extraction in this study. A thermal-hydraulic numerical simulation model is established, and the effect of reservoir properties on heat extraction is investigated. The results show that the growth rate of heat extraction efficiency will decrease as the mining time increases. The initial reservoir temperature has a positive correlation with average production temperature which provides a broad space for the use of extracted thermal energy. The variation of initial reservoir pressure has little effect on the heat extraction performance. A higher matrix permeability leads to a higher average production temperature and heat extraction ratio which prompts more working fluid flow into the matrix, the heat transfer process is enhanced. Under the conditions of this study, the preferred initial reservoir temperature is 493.15 K, the matrix permeability is 10−14m2.