Closed-loop geothermal systems (CLGS) have been recently proposed as an alternative to the conventional enhanced geothermal system (EGS) concept to address many of the issues of concern with EGS, such as potential contamination of the circulating. Deep CLGS wells drilled in rock formations with in-situ temperatures above 200 ℃ could in theory be drilled anywhere around the world, thereby allowing for globally scalable geothermal energy production. A novel deep CLGS (DCLGS) concept with an integrated managed pressure operation (MPO) system is presented here. The concept includes an open-hole completion of the lateral section for improved heat transfer, while the automatically controlled MPO system maintains wellbore integrity and avoids fluid contamination. An integrated thermal and hydraulic model is also developed to demonstrate the feasibility of this concept. Using a robust semi-implicit numerical algorithm, the model simulates the fast transients in the well necessary for automated MPO control. Results show that a 7 km deep U-shaped well with a 7 km open-hole lateral with a reservoir temperature of 222 ℃ can generate a steady-state thermal power of around 45 MW when pump rate is set to 350 m3/h. For the simulated case, it is observed that the open-hole completion of the lateral section and thermal insulation of the exiting section increase the power generation by 15% each. The effect of pump rate is also studied. While the outlet temperature is decreased, the increased pump rate can improve the thermal power by 21%.
