Numerical Investigations of The Three-Dimensional Fractured Geothermal Reservoirs Using The Coupled Thermo Hydro Mechanical Model

The research work focuses on the investigation of the thermal front movement in the fractured geothermal reservoir based on a Thermo-Hydro-Mechanical (THM) numerical simulation model. In this work, we implement the THM model through the COMSOL Multiphysics Solver. The THM model consider that the rock and fluid properties vary with the temperature and strain, and natural fractures are intersected with both injection and production wells in order to maintain the connection between the wells. In our numerical experiments, the orientation and size of the natural fractures are generated randomly following the normal distribution, and the number (density) of natural fractures is also explored. We validate that the number of natural fractures and their intersection with each other drives the thermal recovery performance of the reservoir, as well as the movement of thermal front. Further, the number of natural fractures in the reservoir significantly influences the production temperature. We also evaluate different factors impacting the production temperatures, and conclude that the number of natural fractures, injection rate and injection temperature are among the top factors. There, the developed model is successfully implemented in fractured geothermal reservoirs and the key findings from work is able to help engineers in the aspects of well placement and reservoir performance optimization.