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Thermal Drawdown-Induced Flow Channeling in a Single Fracture in EGS

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The evolution of flow pattern along a single fracture and its effects on heat production is a fundamental problem in the assessments of engineered geothermal systems (EGS). The channelized flow pattern associated with ubiquitous heterogeneity in fracture aperture distribution causes non-uniform temperature decrease in the rock body, which makes the flow increasingly concentrated into some preferential paths through the action of thermal stress. This mechanism may cause rapid heat production deterioration of EGS reservoirs.
In this study, we investigated the effects of aperture heterogeneity on flow pattern evolution in a single fracture in a low-permeability crystalline formation. We developed a numerical model on the platform of GEOS to simulate the coupled thermo-hydro-mechanical processes in a penny-shaped fracture accessed via an injection well and a production well. We find that aperture heterogeneity generally exacerbates flow channeling and reservoir performance generally decreases with longer correlation length of aperture field. The expected production life is highly variable (5 years to beyond 30 years) when the aperture correlation length is longer than 1/5 of the well distance, whereas a heterogeneous fracture behaves similar to a homogeneous one when the correlation length is much shorter than the well distance. Besides, the mean production life decreases with greater aperture standard deviation only when the correlation length is relatively long. Although flow channeling is inevitable, initial aperture fields and well locations that enable tortuous preferential paths tend to prolong heat production lives.

Citation Formats

Lawrence Livermore National Laboratory. (2015). Thermal Drawdown-Induced Flow Channeling in a Single Fracture in EGS [data set]. Retrieved from https://gdr.openei.org/submissions/655.
Export Citation to RIS
Guo, Bin, Fu, Pengcheng, Hao, Yue, Peters, Catherine A., and Carrigan, Charles R. Thermal Drawdown-Induced Flow Channeling in a Single Fracture in EGS. United States: N.p., 15 Nov, 2015. Web. https://gdr.openei.org/submissions/655.
Guo, Bin, Fu, Pengcheng, Hao, Yue, Peters, Catherine A., & Carrigan, Charles R. Thermal Drawdown-Induced Flow Channeling in a Single Fracture in EGS. United States. https://gdr.openei.org/submissions/655
Guo, Bin, Fu, Pengcheng, Hao, Yue, Peters, Catherine A., and Carrigan, Charles R. 2015. "Thermal Drawdown-Induced Flow Channeling in a Single Fracture in EGS". United States. https://gdr.openei.org/submissions/655.
@div{oedi_3399, title = {Thermal Drawdown-Induced Flow Channeling in a Single Fracture in EGS}, author = {Guo, Bin, Fu, Pengcheng, Hao, Yue, Peters, Catherine A., and Carrigan, Charles R.}, abstractNote = {The evolution of flow pattern along a single fracture and its effects on heat production is a fundamental problem in the assessments of engineered geothermal systems (EGS). The channelized flow pattern associated with ubiquitous heterogeneity in fracture aperture distribution causes non-uniform temperature decrease in the rock body, which makes the flow increasingly concentrated into some preferential paths through the action of thermal stress. This mechanism may cause rapid heat production deterioration of EGS reservoirs.
In this study, we investigated the effects of aperture heterogeneity on flow pattern evolution in a single fracture in a low-permeability crystalline formation. We developed a numerical model on the platform of GEOS to simulate the coupled thermo-hydro-mechanical processes in a penny-shaped fracture accessed via an injection well and a production well. We find that aperture heterogeneity generally exacerbates flow channeling and reservoir performance generally decreases with longer correlation length of aperture field. The expected production life is highly variable (5 years to beyond 30 years) when the aperture correlation length is longer than 1/5 of the well distance, whereas a heterogeneous fracture behaves similar to a homogeneous one when the correlation length is much shorter than the well distance. Besides, the mean production life decreases with greater aperture standard deviation only when the correlation length is relatively long. Although flow channeling is inevitable, initial aperture fields and well locations that enable tortuous preferential paths tend to prolong heat production lives.
}, doi = {}, url = {https://gdr.openei.org/submissions/655}, journal = {}, number = , volume = , place = {United States}, year = {2015}, month = {11}}

Details

Data from Nov 15, 2015

Last updated Aug 11, 2017

Submitted Nov 26, 2015

Organization

Lawrence Livermore National Laboratory

Contact

Charles Carrigan

925.422.3941

Authors

Bin Guo

Lawrence Livermore National Laboratory

Pengcheng Fu

Lawrence Livermore National Laboratory

Yue Hao

Lawrence Livermore National Laboratory

Catherine A. Peters

Princeton University

Charles R. Carrigan

Lawrence Livermore National Laboratory

Research Areas

DOE Project Details

Project Name Validation of EGS Feasibility and Explosive Fracturing Techniques

Project Lead Elisabet Metcalfe

Project Number FY15 AOP 1.3.2.4

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