Stress concentration of perforated cement sheath and the effect of cement sheath elastic parameters on its integrity failure during shale gas fracturing
Due to the extremely low porosity and permeability of shale, fracturing is often used to develop shale gas reservoirs. During shale fracturing, extremely high fracturing pressure may invalidate the integrity of the cement sheath and bring hidden dangers to the safe development of shale gas. This pap...
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| Format: | Article |
| Language: | English |
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Frontiers Media S.A.
2022-08-01
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| Series: | Frontiers in Materials |
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| Online Access: | https://www.frontiersin.org/articles/10.3389/fmats.2022.980920/full |
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| author | Yuhuan Bu Yuhuan Bu Heng Yang Heng Yang Lingyun Zhao Lingyun Zhao Shenglai Guo Shenglai Guo Huajie Liu Huajie Liu Xiaolong Ma |
| author_facet | Yuhuan Bu Yuhuan Bu Heng Yang Heng Yang Lingyun Zhao Lingyun Zhao Shenglai Guo Shenglai Guo Huajie Liu Huajie Liu Xiaolong Ma |
| author_sort | Yuhuan Bu |
| collection | DOAJ |
| description | Due to the extremely low porosity and permeability of shale, fracturing is often used to develop shale gas reservoirs. During shale fracturing, extremely high fracturing pressure may invalidate the integrity of the cement sheath and bring hidden dangers to the safe development of shale gas. This paper compares the stress state of the three-dimensional unperforated and perforated finite element models of casing-cement sheath-formation to obtain the influence of perforation on the stress concentration and failure area of the cement sheath. The stress state comparison incorporates three sets of perforation models with different hole densities and diameter verifies the stress concentration law of perforation on the cement sheath. By studying the effects of the elastic modulus and Poisson’s ratio of the cement sheath on the maximum tensile and compressive stresses of the cement sheath under fracturing pressure, the integrity failure form of the cement sheath and the measures for integrity failure are obtained. The results show that the peak stress concentration of the perforated cement sheath is about twice the normal value of the stress. The failure area is the two ends of the perforation, the shape is similar to the bottom surface of the elliptical cone, and the thickness is up to half of the wall thickness of the cement sheath. The line length of the largest failure area is 4.5 times the diameter of the hole. Under fracturing conditions, the cement sheath generally undergoes tensile failure. The lower the elastic modulus and Poisson’s ratio of the cement sheath, the smaller the tensile stress of the cement sheath, and the less likely it is to cause tensile failure. |
| first_indexed | 2024-04-14T02:18:33Z |
| format | Article |
| id | doaj.art-46b43089b1f84226a8a02edd7d23ca1a |
| institution | Directory Open Access Journal |
| issn | 2296-8016 |
| language | English |
| last_indexed | 2024-04-14T02:18:33Z |
| publishDate | 2022-08-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Materials |
| spelling | doaj.art-46b43089b1f84226a8a02edd7d23ca1a2022-12-22T02:18:06ZengFrontiers Media S.A.Frontiers in Materials2296-80162022-08-01910.3389/fmats.2022.980920980920Stress concentration of perforated cement sheath and the effect of cement sheath elastic parameters on its integrity failure during shale gas fracturingYuhuan Bu0Yuhuan Bu1Heng Yang2Heng Yang3Lingyun Zhao4Lingyun Zhao5Shenglai Guo6Shenglai Guo7Huajie Liu8Huajie Liu9Xiaolong Ma10School of Petroleum Engineering, China University of Petroleum (East China), Qingdao, ChinaKey Laboratory of Unconventional Oil and Gas Development, China University of Petroleum (East China), Ministry of Education, Qingdao, ChinaSchool of Petroleum Engineering, China University of Petroleum (East China), Qingdao, ChinaKey Laboratory of Unconventional Oil and Gas Development, China University of Petroleum (East China), Ministry of Education, Qingdao, ChinaKey Laboratory of Unconventional Natural Gas Evaluation and Development in Complex Tectonic Areas, Ministry of Natural Resources, Guiyang, ChinaGuizhou Engineering Research Institute of Oil and Gas Exploration and Development, Guiyang, ChinaSchool of Petroleum Engineering, China University of Petroleum (East China), Qingdao, ChinaKey Laboratory of Unconventional Oil and Gas Development, China University of Petroleum (East China), Ministry of Education, Qingdao, ChinaSchool of Petroleum Engineering, China University of Petroleum (East China), Qingdao, ChinaKey Laboratory of Unconventional Oil and Gas Development, China University of Petroleum (East China), Ministry of Education, Qingdao, ChinaCementing Company, SINOPEC Zhongyuan Oilfield Service Corporation, Beijing, ChinaDue to the extremely low porosity and permeability of shale, fracturing is often used to develop shale gas reservoirs. During shale fracturing, extremely high fracturing pressure may invalidate the integrity of the cement sheath and bring hidden dangers to the safe development of shale gas. This paper compares the stress state of the three-dimensional unperforated and perforated finite element models of casing-cement sheath-formation to obtain the influence of perforation on the stress concentration and failure area of the cement sheath. The stress state comparison incorporates three sets of perforation models with different hole densities and diameter verifies the stress concentration law of perforation on the cement sheath. By studying the effects of the elastic modulus and Poisson’s ratio of the cement sheath on the maximum tensile and compressive stresses of the cement sheath under fracturing pressure, the integrity failure form of the cement sheath and the measures for integrity failure are obtained. The results show that the peak stress concentration of the perforated cement sheath is about twice the normal value of the stress. The failure area is the two ends of the perforation, the shape is similar to the bottom surface of the elliptical cone, and the thickness is up to half of the wall thickness of the cement sheath. The line length of the largest failure area is 4.5 times the diameter of the hole. Under fracturing conditions, the cement sheath generally undergoes tensile failure. The lower the elastic modulus and Poisson’s ratio of the cement sheath, the smaller the tensile stress of the cement sheath, and the less likely it is to cause tensile failure.https://www.frontiersin.org/articles/10.3389/fmats.2022.980920/fullfinite element methodperforated cement sheathfracturingstress concentrationintegrity failure |
| spellingShingle | Yuhuan Bu Yuhuan Bu Heng Yang Heng Yang Lingyun Zhao Lingyun Zhao Shenglai Guo Shenglai Guo Huajie Liu Huajie Liu Xiaolong Ma Stress concentration of perforated cement sheath and the effect of cement sheath elastic parameters on its integrity failure during shale gas fracturing Frontiers in Materials finite element method perforated cement sheath fracturing stress concentration integrity failure |
| title | Stress concentration of perforated cement sheath and the effect of cement sheath elastic parameters on its integrity failure during shale gas fracturing |
| title_full | Stress concentration of perforated cement sheath and the effect of cement sheath elastic parameters on its integrity failure during shale gas fracturing |
| title_fullStr | Stress concentration of perforated cement sheath and the effect of cement sheath elastic parameters on its integrity failure during shale gas fracturing |
| title_full_unstemmed | Stress concentration of perforated cement sheath and the effect of cement sheath elastic parameters on its integrity failure during shale gas fracturing |
| title_short | Stress concentration of perforated cement sheath and the effect of cement sheath elastic parameters on its integrity failure during shale gas fracturing |
| title_sort | stress concentration of perforated cement sheath and the effect of cement sheath elastic parameters on its integrity failure during shale gas fracturing |
| topic | finite element method perforated cement sheath fracturing stress concentration integrity failure |
| url | https://www.frontiersin.org/articles/10.3389/fmats.2022.980920/full |
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