Modelling Thermosyphon-Driven Heat Recovery in Enhanced Geothermal Systems with CMG STARS

Enhanced geothermal systems can deliver continuous, low-carbon energy, but their performance depends on how fluid moves through the system, not just how hot the rock is.

In this study, CMG STARS was used to model a superhot dry rock EGS system with parallel horizontal injector and producer wells connected by hydraulic fractures. 

The results show that injection rate is one of the most important design and operating levers in EGS. At lower injection rates, thermosyphon behavior can sustain flow without pumping. At higher rates, the system enters two-phase conditions earlier, increasing flow complexity and accelerating thermal decline.

Outcome: CMG STARS provided a physics-based framework to evaluate long-term heat recovery, identify operating limits, and support more realistic geothermal development decisions.