Overview of Closed-Loop Enhanced Geothermal Systems

  • Ekrem Alagoz Turkish Petroleum Corporation, R&D Department, Söğütözü, Nizami Gencevi Caddesi No:10, 06510 Çankaya/Ankara, Turkiye
  • Fatimah AlNasser Saudi Aramco, P.O. Box 5000, Dhahran 31311, Saudi Arabia
  • Yasin Ozkan Petroleum Engineering Department, University of Tulsa, OK, USA
  • Emre Can Dundar Turkish Petroleum Corporation, R&D Department, Söğütözü, Nizami Gencevi Caddesi No:10, 06510 Çankaya/Ankara, Turkiye
  • Javid Shiriyev Baku Higher Oil School, Baku, Azerbaijan
Keywords: Geothermal energy, Close-Loop EGS, Hydraulic fractured EGS, Hot dry rock, Renewables


In recent years, the focus of energy industries shifted toward geothermal energy utilization due to environmental concerns. Numerous studies were conducted on Closed-loop and Open-loop Enhanced Geothermal Systems to analyze their feasibility, efficiency, and durability. As different studies focused on various aspects of the system, concerns regarding low heat transfer, circulation efficiency, wellbore instability, and economic viability were left unanswered. Additionally, simulators could not adequately capture the complexity of Enhanced Geothermal Systems (EGS). Another studied system, Advanced Geothermal Systems, has lower costs, better circulation, and no seismic consequences within the closed loop but still suffers from some issues encountered with EGS, such as heat transfer inefficiency. Moreover, geothermal system applicability is limited, especially in deep wells or wells with high thermal gradients. This paper summarizes some of the issues associated with EGS closed-loop systems based on previous studies.


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