Optimizing heat mining strategies in a fractured geothermal reservoir considering fracture deformation effects

Yun Chen, Guowei Ma, Huidong Wang, Tuo Li, Yang Wang, Zizheng Sun

Research output: Contribution to journalArticle

Abstract

A coupled thermo-hydro model is developed for optimizing heat mining strategies in a fractured geothermal reservoir by incorporating material compressibility and fracture deformation. Governing equations for the three-dimensional fluid flow and heat transmission processes in terms of local thermal non-equilibrium concept are discretized using a unified pipe network method. The influence of fracture deformation on the distribution of fluid temperature is investigated using a near-wellbore reservoir model. The development optimization of a geothermal reservoir at Groβ Schönebeck is performed by evaluating heat production over 60 years. Several strategies are designed that involve changing the arrangement of a new horizontal wellbore and hydraulic stimulations. Simulation results for the different strategies, including the outlet fluid temperature drawdown, thermal breakthrough time, and net heat extraction rate, are analysed. Strategies with poor fracture connections feature relatively low flow rates and accumulated thermal production. Strategy 3 to Strategy 6 greatly improve the accumulated thermal production by enhancing fluid circulation in fracture-connected systems. Heat mining efficiency can be improved if a new wellbore is designed in the high-permeability formation and the discontinuities maintain high hydraulic connectivity for fluid circulation. This study provides a numerical method for optimizing geothermal development strategies in terms of economic benefits.

Original languageEnglish
JournalRenewable Energy
DOIs
Publication statusE-pub ahead of print - 11 Oct 2019

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Fluids
Hydraulics
Hot Temperature
Compressibility
Flow of fluids
Numerical methods
Pipe
Flow rate
Temperature
Economics

Cite this

@article{714ec83c6edd4564a4f6c766b2eaf1de,
title = "Optimizing heat mining strategies in a fractured geothermal reservoir considering fracture deformation effects",
abstract = "A coupled thermo-hydro model is developed for optimizing heat mining strategies in a fractured geothermal reservoir by incorporating material compressibility and fracture deformation. Governing equations for the three-dimensional fluid flow and heat transmission processes in terms of local thermal non-equilibrium concept are discretized using a unified pipe network method. The influence of fracture deformation on the distribution of fluid temperature is investigated using a near-wellbore reservoir model. The development optimization of a geothermal reservoir at Groβ Sch{\"o}nebeck is performed by evaluating heat production over 60 years. Several strategies are designed that involve changing the arrangement of a new horizontal wellbore and hydraulic stimulations. Simulation results for the different strategies, including the outlet fluid temperature drawdown, thermal breakthrough time, and net heat extraction rate, are analysed. Strategies with poor fracture connections feature relatively low flow rates and accumulated thermal production. Strategy 3 to Strategy 6 greatly improve the accumulated thermal production by enhancing fluid circulation in fracture-connected systems. Heat mining efficiency can be improved if a new wellbore is designed in the high-permeability formation and the discontinuities maintain high hydraulic connectivity for fluid circulation. This study provides a numerical method for optimizing geothermal development strategies in terms of economic benefits.",
keywords = "Coupled hydro-thermal model, Fracture deformation, Fractured geothermal reservoir, Geothermal development, Net heat extraction rate",
author = "Yun Chen and Guowei Ma and Huidong Wang and Tuo Li and Yang Wang and Zizheng Sun",
year = "2019",
month = "10",
day = "11",
doi = "10.1016/j.renene.2019.10.037",
language = "English",
journal = "Renewable Energy",
issn = "0960-1481",
publisher = "Pergamon",

}

Optimizing heat mining strategies in a fractured geothermal reservoir considering fracture deformation effects. / Chen, Yun; Ma, Guowei; Wang, Huidong; Li, Tuo; Wang, Yang; Sun, Zizheng.

In: Renewable Energy, 11.10.2019.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Optimizing heat mining strategies in a fractured geothermal reservoir considering fracture deformation effects

AU - Chen, Yun

AU - Ma, Guowei

AU - Wang, Huidong

AU - Li, Tuo

AU - Wang, Yang

AU - Sun, Zizheng

PY - 2019/10/11

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N2 - A coupled thermo-hydro model is developed for optimizing heat mining strategies in a fractured geothermal reservoir by incorporating material compressibility and fracture deformation. Governing equations for the three-dimensional fluid flow and heat transmission processes in terms of local thermal non-equilibrium concept are discretized using a unified pipe network method. The influence of fracture deformation on the distribution of fluid temperature is investigated using a near-wellbore reservoir model. The development optimization of a geothermal reservoir at Groβ Schönebeck is performed by evaluating heat production over 60 years. Several strategies are designed that involve changing the arrangement of a new horizontal wellbore and hydraulic stimulations. Simulation results for the different strategies, including the outlet fluid temperature drawdown, thermal breakthrough time, and net heat extraction rate, are analysed. Strategies with poor fracture connections feature relatively low flow rates and accumulated thermal production. Strategy 3 to Strategy 6 greatly improve the accumulated thermal production by enhancing fluid circulation in fracture-connected systems. Heat mining efficiency can be improved if a new wellbore is designed in the high-permeability formation and the discontinuities maintain high hydraulic connectivity for fluid circulation. This study provides a numerical method for optimizing geothermal development strategies in terms of economic benefits.

AB - A coupled thermo-hydro model is developed for optimizing heat mining strategies in a fractured geothermal reservoir by incorporating material compressibility and fracture deformation. Governing equations for the three-dimensional fluid flow and heat transmission processes in terms of local thermal non-equilibrium concept are discretized using a unified pipe network method. The influence of fracture deformation on the distribution of fluid temperature is investigated using a near-wellbore reservoir model. The development optimization of a geothermal reservoir at Groβ Schönebeck is performed by evaluating heat production over 60 years. Several strategies are designed that involve changing the arrangement of a new horizontal wellbore and hydraulic stimulations. Simulation results for the different strategies, including the outlet fluid temperature drawdown, thermal breakthrough time, and net heat extraction rate, are analysed. Strategies with poor fracture connections feature relatively low flow rates and accumulated thermal production. Strategy 3 to Strategy 6 greatly improve the accumulated thermal production by enhancing fluid circulation in fracture-connected systems. Heat mining efficiency can be improved if a new wellbore is designed in the high-permeability formation and the discontinuities maintain high hydraulic connectivity for fluid circulation. This study provides a numerical method for optimizing geothermal development strategies in terms of economic benefits.

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KW - Fractured geothermal reservoir

KW - Geothermal development

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