Experimental Study on the Fracture Behaviors Effect of Stress Conditions on the Fracture of Shale by Super-Critical Carbon Dioxide
This paper examines the fracture propagation problems of supercritical carbon fracturing in low permeability shale. Acoustic emission monitoring and computerized tomography (CT) scanning methods were used to study the influence of initial stress ratios on crack initiation and propagation crack in fr...
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| Format: | Article |
| Language: | English |
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Frontiers Media S.A.
2021-12-01
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| Series: | Frontiers in Energy Research |
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| Online Access: | https://www.frontiersin.org/articles/10.3389/fenrg.2021.763052/full |
| _version_ | 1818402683989524480 |
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| author | Guojun Liu Guojun Liu Yuan Zhao Yuan Zhao Yugang Cheng |
| author_facet | Guojun Liu Guojun Liu Yuan Zhao Yuan Zhao Yugang Cheng |
| author_sort | Guojun Liu |
| collection | DOAJ |
| description | This paper examines the fracture propagation problems of supercritical carbon fracturing in low permeability shale. Acoustic emission monitoring and computerized tomography (CT) scanning methods were used to study the influence of initial stress ratios on crack initiation and propagation crack in fracturing experiments. The results show that crack initiation pressure and crack morphology are very different under different stress conditions. Under the condition of constant confining pressure, when the initial stress ratio λ = 1, cracks are mainly in a horizontal direction; while for an initial stress ratio of λ < 1, cracks are mainly in a vertical direction. With the decrease of λ, crack initiation pressure, reopening pressure, and fracturing liquid volume also decrease, and crack propagation is not as obvious. According to CT scanning results, the crack propagation direction is the same as the maximum principal stress, and fewer cracks are initiated with a smaller initial stress ratio. Based on the acoustic emission characteristics, the fracturing process (including crack initiation, propagation, and closure), can be divided into three stages: 1) the pressure accumulation in the wellbore, 2) Pump Closure; and 3) crack reopening. This study provides the basis for a reasonable selection of shale gas fracturing formation and geo-sequestration of greenhouse gas CO2. |
| first_indexed | 2024-12-14T08:12:16Z |
| format | Article |
| id | doaj.art-674b2715e94743a58d560ff41c264ab0 |
| institution | Directory Open Access Journal |
| issn | 2296-598X |
| language | English |
| last_indexed | 2024-12-14T08:12:16Z |
| publishDate | 2021-12-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Energy Research |
| spelling | doaj.art-674b2715e94743a58d560ff41c264ab02022-12-21T23:10:03ZengFrontiers Media S.A.Frontiers in Energy Research2296-598X2021-12-01910.3389/fenrg.2021.763052763052Experimental Study on the Fracture Behaviors Effect of Stress Conditions on the Fracture of Shale by Super-Critical Carbon DioxideGuojun Liu0Guojun Liu1Yuan Zhao2Yuan Zhao3Yugang Cheng4Hunan Engineering Research Center of Structural Safety and Disaster Prevention for Urban Underground Infrastructure, Hunan City University, Yiyang, ChinaCollege of Civil Engineering and Mechanics, Xiangtan University, Xiangtan, ChinaSinohydro Bureau 8 Co. LTD., POWERCHINA, Changsha, ChinaDepartment of Hydraulic Engineering, Tsinghua University, Beijing, ChinaState Key Laboratory of Mountain Bridge and Tunnel Engineering, Chongqing Jiaotong University, Chongqing, ChinaThis paper examines the fracture propagation problems of supercritical carbon fracturing in low permeability shale. Acoustic emission monitoring and computerized tomography (CT) scanning methods were used to study the influence of initial stress ratios on crack initiation and propagation crack in fracturing experiments. The results show that crack initiation pressure and crack morphology are very different under different stress conditions. Under the condition of constant confining pressure, when the initial stress ratio λ = 1, cracks are mainly in a horizontal direction; while for an initial stress ratio of λ < 1, cracks are mainly in a vertical direction. With the decrease of λ, crack initiation pressure, reopening pressure, and fracturing liquid volume also decrease, and crack propagation is not as obvious. According to CT scanning results, the crack propagation direction is the same as the maximum principal stress, and fewer cracks are initiated with a smaller initial stress ratio. Based on the acoustic emission characteristics, the fracturing process (including crack initiation, propagation, and closure), can be divided into three stages: 1) the pressure accumulation in the wellbore, 2) Pump Closure; and 3) crack reopening. This study provides the basis for a reasonable selection of shale gas fracturing formation and geo-sequestration of greenhouse gas CO2.https://www.frontiersin.org/articles/10.3389/fenrg.2021.763052/fullshale gassuper-critical carbon dioxidecarbon sequestrationmechanical characteristicsacoustic emission |
| spellingShingle | Guojun Liu Guojun Liu Yuan Zhao Yuan Zhao Yugang Cheng Experimental Study on the Fracture Behaviors Effect of Stress Conditions on the Fracture of Shale by Super-Critical Carbon Dioxide Frontiers in Energy Research shale gas super-critical carbon dioxide carbon sequestration mechanical characteristics acoustic emission |
| title | Experimental Study on the Fracture Behaviors Effect of Stress Conditions on the Fracture of Shale by Super-Critical Carbon Dioxide |
| title_full | Experimental Study on the Fracture Behaviors Effect of Stress Conditions on the Fracture of Shale by Super-Critical Carbon Dioxide |
| title_fullStr | Experimental Study on the Fracture Behaviors Effect of Stress Conditions on the Fracture of Shale by Super-Critical Carbon Dioxide |
| title_full_unstemmed | Experimental Study on the Fracture Behaviors Effect of Stress Conditions on the Fracture of Shale by Super-Critical Carbon Dioxide |
| title_short | Experimental Study on the Fracture Behaviors Effect of Stress Conditions on the Fracture of Shale by Super-Critical Carbon Dioxide |
| title_sort | experimental study on the fracture behaviors effect of stress conditions on the fracture of shale by super critical carbon dioxide |
| topic | shale gas super-critical carbon dioxide carbon sequestration mechanical characteristics acoustic emission |
| url | https://www.frontiersin.org/articles/10.3389/fenrg.2021.763052/full |
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