Experimental study on rock fracture toughness under temperature and confining pressure coupling condition
The fracture toughness is an essential mechanical parameter to measure the difficulty of hydraulic fracture expansion. As the reservoir depth increases, the temperature and stress become higher. In particular, the high-temperature and high-pressure characteristics of the 10,000-m-deep reservoir are...
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Frontiers Media S.A.
2025-05-01
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| Series: | Frontiers in Earth Science |
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| Online Access: | https://www.frontiersin.org/articles/10.3389/feart.2025.1603219/full |
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| author | Bo Cai Nailing Xiu Dongxu Li Haifeng Fu Xiaodong Dai Dawei Deng Hexiang Zhao Xueyuan Han Songyang Yuan Liangang Deng |
| author_facet | Bo Cai Nailing Xiu Dongxu Li Haifeng Fu Xiaodong Dai Dawei Deng Hexiang Zhao Xueyuan Han Songyang Yuan Liangang Deng |
| author_sort | Bo Cai |
| collection | DOAJ |
| description | The fracture toughness is an essential mechanical parameter to measure the difficulty of hydraulic fracture expansion. As the reservoir depth increases, the temperature and stress become higher. In particular, the high-temperature and high-pressure characteristics of the 10,000-m-deep reservoir are particularly pronounced. Furthermore, investigating the fracture toughness evolution under such coupled thermomechanical conditions serves as a critical focus of ultra-deep reservoir studies, providing essential insights for optimizing hydraulic fracturing designs. This study investigates the coupled effects of temperature and confining pressure on the fracture toughness of carbonate rocks through systematic experimental and theoretical analyses. Utilizing outcrop samples from the Cambrian Sholbrak Formation (analogous to the 10,000-m-deep target layer of the Ke exploration well), fracture toughness tests were conducted under thermomechanical coupling conditions (25°C–200°C, 0–200 MPa) via the double-wing symmetric crack thick-wall cylinder method implemented on a GCTS high-temperature/high-pressure rock mechanics system. Key findings reveal a temperature-dependent degradation of fracture toughness (40% reduction from 25°C to 200°C at zero confining pressure) and a confining pressure-driven enhancement (76% increase from 0 to 100 MPa at ambient temperature). A damage mechanics-based constitutive model was developed to quantify these dual effects, demonstrating strong agreement with experimental data (mean absolute error <5%). This model addresses the critical gap in fracture toughness characterization under deep reservoir conditions, enabling enhanced accuracy in hydraulic fracture propagation simulations for ultra-deep carbonate reservoir stimulation. |
| format | Article |
| id | doaj-art-01e23341e2b541f7a5fa92d060594c29 |
| institution | DOAJ |
| issn | 2296-6463 |
| language | English |
| publishDate | 2025-05-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Earth Science |
| spelling | doaj-art-01e23341e2b541f7a5fa92d060594c292025-08-20T03:05:56ZengFrontiers Media S.A.Frontiers in Earth Science2296-64632025-05-011310.3389/feart.2025.16032191603219Experimental study on rock fracture toughness under temperature and confining pressure coupling conditionBo Cai0Nailing Xiu1Dongxu Li2Haifeng Fu3Xiaodong Dai4Dawei Deng5Hexiang Zhao6Xueyuan Han7Songyang Yuan8Liangang Deng9China Petroleum Exploration and Development Research Institute, Beijing, ChinaChina Petroleum Exploration and Development Research Institute, Beijing, ChinaNational Key Laboratory of Green Exploitation of Continental Shale Oil, Daqing, Heilongjiang, ChinaChina Petroleum Exploration and Development Research Institute, Beijing, ChinaNational Key Laboratory of Green Exploitation of Continental Shale Oil, Daqing, Heilongjiang, ChinaNational Key Laboratory of Green Exploitation of Continental Shale Oil, Daqing, Heilongjiang, ChinaChina Petroleum Exploration and Development Research Institute, Beijing, ChinaCollege of Petroleum Engineering, China University of Petroleum (Beijing), Beijing, ChinaCollege of Petroleum Engineering, China University of Petroleum (Beijing), Beijing, ChinaSchool of Civil Engineering and Geomatics, Southwest Petroleum University, Chengdu, Sichuan, ChinaThe fracture toughness is an essential mechanical parameter to measure the difficulty of hydraulic fracture expansion. As the reservoir depth increases, the temperature and stress become higher. In particular, the high-temperature and high-pressure characteristics of the 10,000-m-deep reservoir are particularly pronounced. Furthermore, investigating the fracture toughness evolution under such coupled thermomechanical conditions serves as a critical focus of ultra-deep reservoir studies, providing essential insights for optimizing hydraulic fracturing designs. This study investigates the coupled effects of temperature and confining pressure on the fracture toughness of carbonate rocks through systematic experimental and theoretical analyses. Utilizing outcrop samples from the Cambrian Sholbrak Formation (analogous to the 10,000-m-deep target layer of the Ke exploration well), fracture toughness tests were conducted under thermomechanical coupling conditions (25°C–200°C, 0–200 MPa) via the double-wing symmetric crack thick-wall cylinder method implemented on a GCTS high-temperature/high-pressure rock mechanics system. Key findings reveal a temperature-dependent degradation of fracture toughness (40% reduction from 25°C to 200°C at zero confining pressure) and a confining pressure-driven enhancement (76% increase from 0 to 100 MPa at ambient temperature). A damage mechanics-based constitutive model was developed to quantify these dual effects, demonstrating strong agreement with experimental data (mean absolute error <5%). This model addresses the critical gap in fracture toughness characterization under deep reservoir conditions, enabling enhanced accuracy in hydraulic fracture propagation simulations for ultra-deep carbonate reservoir stimulation.https://www.frontiersin.org/articles/10.3389/feart.2025.1603219/fullfracture toughnesstemperatureconfining pressurerock mechanicscarbonate rock |
| spellingShingle | Bo Cai Nailing Xiu Dongxu Li Haifeng Fu Xiaodong Dai Dawei Deng Hexiang Zhao Xueyuan Han Songyang Yuan Liangang Deng Experimental study on rock fracture toughness under temperature and confining pressure coupling condition Frontiers in Earth Science fracture toughness temperature confining pressure rock mechanics carbonate rock |
| title | Experimental study on rock fracture toughness under temperature and confining pressure coupling condition |
| title_full | Experimental study on rock fracture toughness under temperature and confining pressure coupling condition |
| title_fullStr | Experimental study on rock fracture toughness under temperature and confining pressure coupling condition |
| title_full_unstemmed | Experimental study on rock fracture toughness under temperature and confining pressure coupling condition |
| title_short | Experimental study on rock fracture toughness under temperature and confining pressure coupling condition |
| title_sort | experimental study on rock fracture toughness under temperature and confining pressure coupling condition |
| topic | fracture toughness temperature confining pressure rock mechanics carbonate rock |
| url | https://www.frontiersin.org/articles/10.3389/feart.2025.1603219/full |
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