Genetic Types and Main Control Factors of Microfractures in Tight Oil Reservoirs of Jimsar Sag
Microfractures are key for migrating and aggregating hydrocarbon source rocks and fracturing oil-gas exploitation in tight reservoirs. In this study, rock samples from the Lucaogou Formation tight reservoirs in Xinjiang, China, were studied using multidisciplinary techniques to investigate the genet...
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| Format: | Article |
| Language: | English |
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Wiley
2021-01-01
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| Series: | Geofluids |
| Online Access: | http://dx.doi.org/10.1155/2021/5558551 |
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| author | Xiangye Kong Jianhui Zeng Xianfeng Tan Haowei Yuan Dan Liu Qun Luo Qianyou Wang Rusi Zuo |
| author_facet | Xiangye Kong Jianhui Zeng Xianfeng Tan Haowei Yuan Dan Liu Qun Luo Qianyou Wang Rusi Zuo |
| author_sort | Xiangye Kong |
| collection | DOAJ |
| description | Microfractures are key for migrating and aggregating hydrocarbon source rocks and fracturing oil-gas exploitation in tight reservoirs. In this study, rock samples from the Lucaogou Formation tight reservoirs in Xinjiang, China, were studied using multidisciplinary techniques to investigate the genetic types and main control factors of microfractures. Results indicated that the Lucaogou Formation mainly developed diagenetic microfractures followed by tectonic microfractures, with slight formations of granular microfractures. These observations were used to clarify the relationship between the development of microfractures and the pore fluid content, lithology, mineral composition, and stratum thickness. A higher pore fluid content corresponded to a lower compressive strength of the rocks and a larger ring count, resulting in a higher probability of failure and microfracture formation. Tight reservoirs containing more quartz and carbonate minerals were found to develop more microfractures. Quartz grains showed fractures at the margins under stress, which increased the pore permeability of rocks. Carbonate minerals tended to form microfractures owing to corrosion. Microfracture formation mechanisms differed depending on lithology, and microfractures were found to develop most in dolomite and dolomitic siltstones and least in mudstone. Muddy rocks developed fewer tectonic fractures because they can easily absorb stress and undergo plastic deformation. Within a certain stratum thickness range, the average single-well fracture space and stratum thickness showed positive correlations. Moreover, the fracture space increased and the fracture density decreased as the stratum thickness increased. When the stratum thickness was less than 2.5 m, the fracture space increased linearly with the stratum thickness, and when the stratum thickness was greater than 2.5 m, the fracture space remained constant. This study will provide an essential scientific basis for enhancing tight oil recovery. |
| format | Article |
| id | doaj-art-359ace2bad554d8db9afc68baae54755 |
| institution | Kabale University |
| issn | 1468-8115 1468-8123 |
| language | English |
| publishDate | 2021-01-01 |
| publisher | Wiley |
| record_format | Article |
| series | Geofluids |
| spelling | doaj-art-359ace2bad554d8db9afc68baae547552025-02-03T06:10:46ZengWileyGeofluids1468-81151468-81232021-01-01202110.1155/2021/55585515558551Genetic Types and Main Control Factors of Microfractures in Tight Oil Reservoirs of Jimsar SagXiangye Kong0Jianhui Zeng1Xianfeng Tan2Haowei Yuan3Dan Liu4Qun Luo5Qianyou Wang6Rusi Zuo7College of Geosciences, China University of Petroleum, Beijing 102249, ChinaCollege of Geosciences, China University of Petroleum, Beijing 102249, ChinaCollege of Petroleum and Gas Engineering, Chongqing University of Science and Technology, Chongqing 401331, ChinaCollege of Geosciences, China University of Petroleum, Beijing 102249, ChinaInstitute of Exploration Techniques, CAGS, Langfang Hebei 065000, ChinaUnconventional Natural Gas Institute, China University of Petroleum, Beijing 102249, ChinaDepartment of Earth, Ocean and Ecological Sciences, University of Liverpool, Liverpool L69 3GP, UKState Key Laboratory of Marine Geology, Tongji University, Shanghai 200092, ChinaMicrofractures are key for migrating and aggregating hydrocarbon source rocks and fracturing oil-gas exploitation in tight reservoirs. In this study, rock samples from the Lucaogou Formation tight reservoirs in Xinjiang, China, were studied using multidisciplinary techniques to investigate the genetic types and main control factors of microfractures. Results indicated that the Lucaogou Formation mainly developed diagenetic microfractures followed by tectonic microfractures, with slight formations of granular microfractures. These observations were used to clarify the relationship between the development of microfractures and the pore fluid content, lithology, mineral composition, and stratum thickness. A higher pore fluid content corresponded to a lower compressive strength of the rocks and a larger ring count, resulting in a higher probability of failure and microfracture formation. Tight reservoirs containing more quartz and carbonate minerals were found to develop more microfractures. Quartz grains showed fractures at the margins under stress, which increased the pore permeability of rocks. Carbonate minerals tended to form microfractures owing to corrosion. Microfracture formation mechanisms differed depending on lithology, and microfractures were found to develop most in dolomite and dolomitic siltstones and least in mudstone. Muddy rocks developed fewer tectonic fractures because they can easily absorb stress and undergo plastic deformation. Within a certain stratum thickness range, the average single-well fracture space and stratum thickness showed positive correlations. Moreover, the fracture space increased and the fracture density decreased as the stratum thickness increased. When the stratum thickness was less than 2.5 m, the fracture space increased linearly with the stratum thickness, and when the stratum thickness was greater than 2.5 m, the fracture space remained constant. This study will provide an essential scientific basis for enhancing tight oil recovery.http://dx.doi.org/10.1155/2021/5558551 |
| spellingShingle | Xiangye Kong Jianhui Zeng Xianfeng Tan Haowei Yuan Dan Liu Qun Luo Qianyou Wang Rusi Zuo Genetic Types and Main Control Factors of Microfractures in Tight Oil Reservoirs of Jimsar Sag Geofluids |
| title | Genetic Types and Main Control Factors of Microfractures in Tight Oil Reservoirs of Jimsar Sag |
| title_full | Genetic Types and Main Control Factors of Microfractures in Tight Oil Reservoirs of Jimsar Sag |
| title_fullStr | Genetic Types and Main Control Factors of Microfractures in Tight Oil Reservoirs of Jimsar Sag |
| title_full_unstemmed | Genetic Types and Main Control Factors of Microfractures in Tight Oil Reservoirs of Jimsar Sag |
| title_short | Genetic Types and Main Control Factors of Microfractures in Tight Oil Reservoirs of Jimsar Sag |
| title_sort | genetic types and main control factors of microfractures in tight oil reservoirs of jimsar sag |
| url | http://dx.doi.org/10.1155/2021/5558551 |
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