Heat Transfer Modelling of an Unconventional, Closed-Loop Geothermal Well

Renaud, T., Verdin, P., Pan, L. and Falcone, G. (2021) Heat Transfer Modelling of an Unconventional, Closed-Loop Geothermal Well. In: World Geothermal Congress 2020, Reykjavik, Iceland, 21-26 May 2021,

Abstract

With approximately 13 GW installed capacity worldwide in 2017, the geothermal energy sector represents less than 1% of the total renewable energy mix. Although the Enhanced Geothermal System (EGS) concept faces technical and economic validation challenges and suffers from public acceptance issues, such system is considered to have the capability to unlock the significant deep geothermal potential worldwide. The development of unconventional deep well designs can help to improve the efficiency and reliability of EGS systems. An integrated reservoir-wellbore approach to model alternative EGS well designs is key to assess their long-term hydraulic and thermal performance, particularly in unconventional geological settings. A coupled wellbore-reservoir simulator, T2WELL/EOS1, is used to compare the estimated energy recovery with experimental results available in the public domain from a downhole coaxial heat exchanger (DCHE) installed in Hawaii, where a temperature of 358°C has been measured at a depth of 1962 m. Numerical results are also compared with analytical-based results from the literature, showing good agreement and demonstrating that the heat recovery from deep borehole heat exchangers can be accurately simulated. Thermal performance and economic viability of a hypothetical DCHE with conducting fillers in high thermal gradient areas are also discussed, based on the results from the Hawaii case study. The findings provide guidance to assess the operating range of closedloop single-well EGS designs in future studies.

• Item Type: Conference Proceedings
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Falcone, Professor Gioia
• Authors: Renaud, T., Verdin, P., Pan, L., and Falcone, G.
• College/School: College of Science and Engineering > School of Engineering > Systems Power and Energy
• Copyright Holders: Copyright © World Geothermal Congress 2021
• First Published: First published in Proceedings of World Geothermal Conference 2020+1
• Publisher Policy: Reproduced with the permission of the publisher

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