Thermo-hydro-mechanical modelling study of heat extraction and flow processes in enhanced geothermal systems

Publikationstyp
Journal Article
Date Issued
2021-06-08
Sprache
English
Author(s)
Zhou, Dejian  
Tatomir, Alexandru-Bogdan  
Sauter, Martin  
Institut
Geohydroinformatik B-9  
TORE-DOI
10.15480/882.3645
TORE-URI
http://hdl.handle.net/11420/9857
Journal
Advances in geosciences  
Volume
54
Start Page
229
End Page
240
Citation
Advances in Geosciences 54: 229-240 (2021-06-08)
Publisher DOI
10.5194/adgeo-54-229-2021
Scopus ID
2-s2.0-85107708992
Publisher
European Geosciences Union
Enhanced Geothermal Systems (EGS) are widely used in the development and application of geothermal energy production. They usually consist of two deep boreholes (well doublet) circulation systems, with hot water being abstracted, passed through a heat exchanger, and reinjected into the geothermal reservoir. Recently, simple analytical solutions have been proposed to estimate water pressure at the abstraction borehole. Nevertheless, these methods do not consider the influence of complex geometrical fracture patterns and the effects of the coupled thermal and mechanical processes. In this study, we implemented a coupled thermohydro-mechanical (THM) model to simulate the processes of heat extraction, reservoir deformation, and groundwater flow in the fractured rock reservoir. The THM model is validated with analytical solutions and existing published results. The results from the systems of single fracture zone and multi-fracture zones are investigated and compared. It shows that the growth of the number and spacing of fracture zones can effectively decrease the pore pressure difference between injection and abstraction wells; it also increases the production temperature at the abstraction, the service life-spans, and heat production rate of the geothermal reservoirs. Furthermore, the sensitivity analysis on the flow rate is also implemented. It is observed that a larger flow rate leads to a higher abstraction temperature and heat production rate at the end of the simulation, but the pressure difference may become lower.
DDC Class
004: Informatik
550: Geowissenschaften
More Funding Information
This research has been supported by the China Scholarship Council (grant no. 1). This open-access publication was funded by the University of Göttingen.
Publication version
publishedVersion
Lizenz
https://creativecommons.org/licenses/by/4.0/
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