Revisiting the normal stiffness–permeability relations for shale fractures under true triaxial stress
Understanding the relationship between normal stiffness and permeability in rock fractures under high and true-triaxial in situ stress conditions is critical to assess hydro-mechanical coupling in the Earth's crust. Previous data on stiffness–permeability relations are measured under uniaxial s...
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Elsevier
2025-08-01
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| Series: | Journal of Rock Mechanics and Geotechnical Engineering |
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| Online Access: | http://www.sciencedirect.com/science/article/pii/S1674775525000150 |
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| author | Fudong Li Derek Elsworth Xia-Ting Feng Tianyu Chen Jun Zhao Yingchun Li Jianyu Zhang Qiong Wu Guanglei Cui |
| author_facet | Fudong Li Derek Elsworth Xia-Ting Feng Tianyu Chen Jun Zhao Yingchun Li Jianyu Zhang Qiong Wu Guanglei Cui |
| author_sort | Fudong Li |
| collection | DOAJ |
| description | Understanding the relationship between normal stiffness and permeability in rock fractures under high and true-triaxial in situ stress conditions is critical to assess hydro-mechanical coupling in the Earth's crust. Previous data on stiffness–permeability relations are measured under uniaxial stress states as well as under normal stress. However, many projects involve faulted formations with complex three-dimensional (3D) stress states or significant changes to the original stress state. We rectified this by following the permeability evolution using a true-triaxial stress-permeability apparatus as well as independently applying a spectrum of triaxial stresses from low to high. The relationship between permeability and fracture normal stiffness was quantified using constraints based on the principle of virtual work. The impacts of fracture-lateral and fracture-normal stresses on permeability and normal stiffness evolution were measured. It was found that permeability decreases with increasing fracture-lateral and fracture-normal stresses as a result of Poisson confinement, independent of the orientation of the fracture relative to the stresses. The lateral stresses dominated the evolution of normal stiffness at lower normal stresses (σ3 = 10 MPa) and played a supplementary role at higher normal stresses (σ3 > 10 MPa). Moreover, correlations between the evolution of permeability and normal stiffness were extended beyond the low-stiffness, high-permeability region to the high-stiffness, low-permeability region under high fracture-lateral stresses (10–80 MPa) with fracture-normal stress (10–50 MPa) conditions. Again, high lateral stresses further confined the fracture and therefore reduced permeability and increased normal stiffness, which exceeded the previous reported stiffness under no lateral stress conditions. This process enabled us to identify a fundamental change in the flow regime from multi-channel to isolated channelized flow. These results provide important characterizations of fracture permeability in the deep crust, including recovery from deep shale-gas reservoirs. |
| format | Article |
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| institution | Kabale University |
| issn | 1674-7755 |
| language | English |
| publishDate | 2025-08-01 |
| publisher | Elsevier |
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| series | Journal of Rock Mechanics and Geotechnical Engineering |
| spelling | doaj-art-b3a70f8ac0e3415aa2cbdbac72e68e6c2025-08-20T03:40:41ZengElsevierJournal of Rock Mechanics and Geotechnical Engineering1674-77552025-08-011785001501710.1016/j.jrmge.2025.01.007Revisiting the normal stiffness–permeability relations for shale fractures under true triaxial stressFudong Li0Derek Elsworth1Xia-Ting Feng2Tianyu Chen3Jun Zhao4Yingchun Li5Jianyu Zhang6Qiong Wu7Guanglei Cui8Key Laboratory of Ministry of Education on Safe Mining of Deep Metal Mines, School of Resources and Civil Engineering and Key Laboratory of Liaoning Province on Deep Engineering and Intelligent Technology, Northeastern University, Shenyang, 110819, ChinaDepartment of Energy and Mineral Engineering, EMS Energy Institute and G3 Center, Pennsylvania State University, University Park, PA, 16802, USAKey Laboratory of Ministry of Education on Safe Mining of Deep Metal Mines, School of Resources and Civil Engineering and Key Laboratory of Liaoning Province on Deep Engineering and Intelligent Technology, Northeastern University, Shenyang, 110819, ChinaKey Laboratory of Ministry of Education on Safe Mining of Deep Metal Mines, School of Resources and Civil Engineering and Key Laboratory of Liaoning Province on Deep Engineering and Intelligent Technology, Northeastern University, Shenyang, 110819, China; State Key Laboratory of Coal Mine Safety Technology, China Coal Technology & Engineering Group Shenyang Research Institute, Shenfu Demonstration Zone, Shenyang, 113122, China; National Energy Shale Gas R&D (Experiment) Center, Langfang, 065007, China; Corresponding author. Key Laboratory of Ministry of Education on Safe Mining of Deep Metal Mines, School of Resources and Civil Engineering and Key Laboratory of Liaoning Province on Deep Engineering and Intelligent Technology, Northeastern University, Shenyang, 110819, China.Key Laboratory of Ministry of Education on Safe Mining of Deep Metal Mines, School of Resources and Civil Engineering and Key Laboratory of Liaoning Province on Deep Engineering and Intelligent Technology, Northeastern University, Shenyang, 110819, ChinaState Key Laboratory of Coastal and Offshore Engineering, Dalian University of Technology, Dalian, 116024, ChinaNo. 3 Oil Production Plant of Daqing Oilfield Company Ltd, Daqing, 163113, ChinaNo. 4 Oil Production Plant of Daqing Oilfield Company Ltd, Daqing, 163511, ChinaKey Laboratory of Ministry of Education on Safe Mining of Deep Metal Mines, School of Resources and Civil Engineering and Key Laboratory of Liaoning Province on Deep Engineering and Intelligent Technology, Northeastern University, Shenyang, 110819, China; Corresponding author.Understanding the relationship between normal stiffness and permeability in rock fractures under high and true-triaxial in situ stress conditions is critical to assess hydro-mechanical coupling in the Earth's crust. Previous data on stiffness–permeability relations are measured under uniaxial stress states as well as under normal stress. However, many projects involve faulted formations with complex three-dimensional (3D) stress states or significant changes to the original stress state. We rectified this by following the permeability evolution using a true-triaxial stress-permeability apparatus as well as independently applying a spectrum of triaxial stresses from low to high. The relationship between permeability and fracture normal stiffness was quantified using constraints based on the principle of virtual work. The impacts of fracture-lateral and fracture-normal stresses on permeability and normal stiffness evolution were measured. It was found that permeability decreases with increasing fracture-lateral and fracture-normal stresses as a result of Poisson confinement, independent of the orientation of the fracture relative to the stresses. The lateral stresses dominated the evolution of normal stiffness at lower normal stresses (σ3 = 10 MPa) and played a supplementary role at higher normal stresses (σ3 > 10 MPa). Moreover, correlations between the evolution of permeability and normal stiffness were extended beyond the low-stiffness, high-permeability region to the high-stiffness, low-permeability region under high fracture-lateral stresses (10–80 MPa) with fracture-normal stress (10–50 MPa) conditions. Again, high lateral stresses further confined the fracture and therefore reduced permeability and increased normal stiffness, which exceeded the previous reported stiffness under no lateral stress conditions. This process enabled us to identify a fundamental change in the flow regime from multi-channel to isolated channelized flow. These results provide important characterizations of fracture permeability in the deep crust, including recovery from deep shale-gas reservoirs.http://www.sciencedirect.com/science/article/pii/S1674775525000150Fracture permeabilityDeformationFracture normal stiffnessTrue-triaxial stressPrinciple of virtual work |
| spellingShingle | Fudong Li Derek Elsworth Xia-Ting Feng Tianyu Chen Jun Zhao Yingchun Li Jianyu Zhang Qiong Wu Guanglei Cui Revisiting the normal stiffness–permeability relations for shale fractures under true triaxial stress Journal of Rock Mechanics and Geotechnical Engineering Fracture permeability Deformation Fracture normal stiffness True-triaxial stress Principle of virtual work |
| title | Revisiting the normal stiffness–permeability relations for shale fractures under true triaxial stress |
| title_full | Revisiting the normal stiffness–permeability relations for shale fractures under true triaxial stress |
| title_fullStr | Revisiting the normal stiffness–permeability relations for shale fractures under true triaxial stress |
| title_full_unstemmed | Revisiting the normal stiffness–permeability relations for shale fractures under true triaxial stress |
| title_short | Revisiting the normal stiffness–permeability relations for shale fractures under true triaxial stress |
| title_sort | revisiting the normal stiffness permeability relations for shale fractures under true triaxial stress |
| topic | Fracture permeability Deformation Fracture normal stiffness True-triaxial stress Principle of virtual work |
| url | http://www.sciencedirect.com/science/article/pii/S1674775525000150 |
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