Variable Fracture Conductivity to Enhance Heat Extraction in EGS

The performance of an enhanced geothermal reservoir relies on circulating the working fluid to extract heat from subsurface. To avoid any “fast flow paths” that may short-circuit the water and cause an early thermal breakthrough in the enhanced geothermal systems (EGS), we discuss a new concept for tuning fracture conductivity. The aim of utilizing this method is to provide high fracture conductivity in high temperature zones and low fracture conductivity in low temperature zones as a potential technique in future. Results show that, for the well pair with several induced fractures connecting with each other, using this technique would avoid the appearance of any dominant flow paths between wells and could enable to maintain high production temperature. By comparing the generated power according to different simulation scenarios, it could be known that, after a continuous production of 50 years, cumulative output thermal power with this new technique could be over 38.29% higher than the scheme without it which is significantly considerable in the development of EGS. Since standard approaches for altering flow are mainly focused on near-wellbore areas, we are now looking to control the flow far away inside the reservoir. In this research, we expect to provide a new insight for clean, environmental, and highly efficient development of EGS.