Saline–CO<sub>2</sub> Solution Effects on the Mechanical Properties of Sandstones: An Experimental Study
In deep brine oil and gas injection–production operations, the combined long-term effects of brine and carbon dioxide on rock mechanical properties are not clear. In order to solve this problem, the influence of long-term salt–CO<sub>2</sub> environment on the mechanical properties of sa...
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2025-01-01
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| author | Motao Duan Haijun Mao Guangquan Zhang Junxin Liu Sinan Zhu Di Wang Hao Xie |
| author_facet | Motao Duan Haijun Mao Guangquan Zhang Junxin Liu Sinan Zhu Di Wang Hao Xie |
| author_sort | Motao Duan |
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| description | In deep brine oil and gas injection–production operations, the combined long-term effects of brine and carbon dioxide on rock mechanical properties are not clear. In order to solve this problem, the influence of long-term salt–CO<sub>2</sub> environment on the mechanical properties of sandstone is discussed. The mechanism of interaction evolution and fracture propagation was studied in detail by NMR, the triaxial compression test and a CT scan. The results show that the triaxial compressive strength and mass of sandstone decrease first and then increase with the prolonging of soaking time. The proportion of micropores first decreased and then increased, while the proportion of medium and large pores first increased and then decreased. The pores obtained by Avizo’s segmentation of the threshold value of CT sections first increased and then decreased, and the fractal dimensions obtained first increased and then decreased. In particular, the calcium ions in the immersion solution increased first and then decreased. The reaction rate was obtained and verified according to the changes in calcium carbonate mass and calcium ion mineralization at different times. The failure mode of the sample gradually changed from /-shaped failure to V-shaped composite failure, then to local /-shaped failure, and finally to X-shaped composite failure. On this basis, the process of sandstone was divided into the dissolution stage, precipitation stage and secondary dissolution stage, and the rock microstructure change model under a salt–CO<sub>2</sub> environment was established. The mechanics, temperature, chemical interaction mechanism and fracture propagation mechanism of sandstone under a salt–CO<sub>2</sub> environment are discussed. |
| format | Article |
| id | doaj-art-4d8713db5da14090951786020ba521b0 |
| institution | Kabale University |
| issn | 2076-3417 |
| language | English |
| publishDate | 2025-01-01 |
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| spelling | doaj-art-4d8713db5da14090951786020ba521b02025-01-24T13:20:02ZengMDPI AGApplied Sciences2076-34172025-01-0115260710.3390/app15020607Saline–CO<sub>2</sub> Solution Effects on the Mechanical Properties of Sandstones: An Experimental StudyMotao Duan0Haijun Mao1Guangquan Zhang2Junxin Liu3Sinan Zhu4Di Wang5Hao Xie6School of Civil Engineering and Architecture, Southwest University of Science and Technology, Mianyang 621010, ChinaState Key Laboratory of Geomechanics and Geotechnical Engineering, Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, Wuhan 430071, ChinaChina Petroleum Exploration and Development Research Institute, China Petroleum & Chemical Corporation, Beijing 102206, ChinaSchool of Civil Engineering and Architecture, Southwest University of Science and Technology, Mianyang 621010, ChinaChina Petroleum Exploration and Development Research Institute, China Petroleum & Chemical Corporation, Beijing 102206, ChinaSchool of Civil Engineering and Architecture, Southwest University of Science and Technology, Mianyang 621010, ChinaSchool of Civil Engineering and Architecture, Southwest University of Science and Technology, Mianyang 621010, ChinaIn deep brine oil and gas injection–production operations, the combined long-term effects of brine and carbon dioxide on rock mechanical properties are not clear. In order to solve this problem, the influence of long-term salt–CO<sub>2</sub> environment on the mechanical properties of sandstone is discussed. The mechanism of interaction evolution and fracture propagation was studied in detail by NMR, the triaxial compression test and a CT scan. The results show that the triaxial compressive strength and mass of sandstone decrease first and then increase with the prolonging of soaking time. The proportion of micropores first decreased and then increased, while the proportion of medium and large pores first increased and then decreased. The pores obtained by Avizo’s segmentation of the threshold value of CT sections first increased and then decreased, and the fractal dimensions obtained first increased and then decreased. In particular, the calcium ions in the immersion solution increased first and then decreased. The reaction rate was obtained and verified according to the changes in calcium carbonate mass and calcium ion mineralization at different times. The failure mode of the sample gradually changed from /-shaped failure to V-shaped composite failure, then to local /-shaped failure, and finally to X-shaped composite failure. On this basis, the process of sandstone was divided into the dissolution stage, precipitation stage and secondary dissolution stage, and the rock microstructure change model under a salt–CO<sub>2</sub> environment was established. The mechanics, temperature, chemical interaction mechanism and fracture propagation mechanism of sandstone under a salt–CO<sub>2</sub> environment are discussed.https://www.mdpi.com/2076-3417/15/2/607sandstoneCO<sub>2</sub> solutionsalinity formulanuclear magnetic resonance (NMR)pore |
| spellingShingle | Motao Duan Haijun Mao Guangquan Zhang Junxin Liu Sinan Zhu Di Wang Hao Xie Saline–CO<sub>2</sub> Solution Effects on the Mechanical Properties of Sandstones: An Experimental Study Applied Sciences sandstone CO<sub>2</sub> solution salinity formula nuclear magnetic resonance (NMR) pore |
| title | Saline–CO<sub>2</sub> Solution Effects on the Mechanical Properties of Sandstones: An Experimental Study |
| title_full | Saline–CO<sub>2</sub> Solution Effects on the Mechanical Properties of Sandstones: An Experimental Study |
| title_fullStr | Saline–CO<sub>2</sub> Solution Effects on the Mechanical Properties of Sandstones: An Experimental Study |
| title_full_unstemmed | Saline–CO<sub>2</sub> Solution Effects on the Mechanical Properties of Sandstones: An Experimental Study |
| title_short | Saline–CO<sub>2</sub> Solution Effects on the Mechanical Properties of Sandstones: An Experimental Study |
| title_sort | saline co sub 2 sub solution effects on the mechanical properties of sandstones an experimental study |
| topic | sandstone CO<sub>2</sub> solution salinity formula nuclear magnetic resonance (NMR) pore |
| url | https://www.mdpi.com/2076-3417/15/2/607 |
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