Previous studies have found that flow channeling induced by thermal drawdown in fractured reservoirs has significant effects on performance of engineered geothermal systems (EGS). The current study evaluates various well layout schemes through coupled thermal-hydrological-mechanics (THM) simulations. The main objective is to investigate the flow channeling potential of these layouts and identify layouts that are less susceptible to flow channeling. The study finds that different well layouts have different levels of susceptibility to flow channeling. The layout consisting of an injection-production pair along the minimum principal stress direction yields very slow extension of the cooling front from the injection well toward the production well. This scenario would yield superb thermal performance if the reservoir itself contains a sufficient amount of fluid to sustain long-term production, and circulation between the two wells is unessential. On the other hand, if direct circulation between the injection and production wells is desired, the configuration with one injection well at the center supplying fluid to four production wells around it seems to be a promising solution. Each of the production wells outperforms the control scenario, where a single injection-production doublet is oriented along the maximum horizontal principal stress direction, and the circulation rate-drilling cost ratio is remarkably higher.

Press the Back button in your browser, or search again.

Copyright 2014, Stanford Geothermal Program: Readers who download papers from this site should honor the copyright of the original authors and may not copy or distribute the work further without the permission of the original publisher.