Characterization of natural fractures in tight sandstone reservoirs in Yuanba area, northern Sichuan Basin
Natural fractures are quite important for the high and stable production of tight sandstone gas reservoirs. However, it is commonly difficult to accurately characterize their distribution in tight sandstone gas reservoirs due to the strong heterogeneity. A comprehensive characterization of natural f...
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| Format: | Article |
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KeAi Communications Co., Ltd.
2023-01-01
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| Series: | Unconventional Resources |
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| Online Access: | http://www.sciencedirect.com/science/article/pii/S2666519023000080 |
| _version_ | 1797682800446406656 |
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| author | Yanqing Huang Ruyue Wang |
| author_facet | Yanqing Huang Ruyue Wang |
| author_sort | Yanqing Huang |
| collection | DOAJ |
| description | Natural fractures are quite important for the high and stable production of tight sandstone gas reservoirs. However, it is commonly difficult to accurately characterize their distribution in tight sandstone gas reservoirs due to the strong heterogeneity. A comprehensive characterization of natural fractures in tight sandstone gas reservoirs of the Xujiahe Formation in the Yuanba area, Sichuan Basin, was carried out by multimethod of core description, log interpretation and seismic prediction. The results show that (1) the natural fractures in the Xujiahe Formation are mainly low-angle fractures, with a few medium- and high-angle fractures. The degree of fracture development is mainly controlled by the distance from the fault, the flexural degree of the strata and the thickness of the rock mechanical layer. (2) The fracture-sensitive seismic attributes such as the preferred maximum likelihood, structure entropy, illuminant-based symmetry and high-precision curvature are taken as the input, and the unsupervised cluster analysis algorithm based on Bayesian probability model is applied to predict the distribution of large-scale fractures at different dip angles; on the basis of narrow azimuthal pre-stack CMP gather optimization, the anisotropy detection technique of Hampson-Russell's ProAZ full CMP gather is used to characterize the distribution of small- and medium-scale fractures, and the predicted fracture development intensity matches the fracture interpretation results of the imaging logs by more than 85%. Moreover, the predicted fracture orientation is basically consistent with that of the imaging loggings. (3) The fault-genesis fractures of the Xujiahe Formation are mainly distributed near the fault on the southeast flank of the Jiulongshan anticline, and are distributed in a narrow strip in NE direction. The fold-genesis fractures are mainly developed in the Xu 3rd Member, and are located in the axis of the Jiulongshan anticline and its southeast flank where the strata are strongly flexed. This study provides a solid foundation for the development of tight sandstone gas reservoirs and extends the approaches for the accurate characterization of fractures. |
| first_indexed | 2024-03-12T00:05:04Z |
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| language | English |
| last_indexed | 2024-03-12T00:05:04Z |
| publishDate | 2023-01-01 |
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| series | Unconventional Resources |
| spelling | doaj.art-550c43583a794455a4889422fcab2d9b2023-09-17T04:57:41ZengKeAi Communications Co., Ltd.Unconventional Resources2666-51902023-01-013155163Characterization of natural fractures in tight sandstone reservoirs in Yuanba area, northern Sichuan BasinYanqing Huang0Ruyue Wang1Sinopec Petroleum Exploration and Production Research Institute, Beijing, 102206, China; State Key Laboratory of Shale Oil and Gas Enrichment Mechanisms and Efficient Development, Beijing, 102206, China; Sinopec Key Laboratory of Shale Oil/Gas Exploration and Production Technology, Beijing, 102206, China; Corresponding author. Sinopec Petroleum Exploration and Production Research Institute, Beijing, 102206, China.;Sinopec Petroleum Exploration and Production Research Institute, Beijing, 102206, China; State Key Laboratory of Shale Oil and Gas Enrichment Mechanisms and Efficient Development, Beijing, 102206, China; Sinopec Key Laboratory of Shale Oil/Gas Exploration and Production Technology, Beijing, 102206, China; Corresponding author. Sinopec Petroleum Exploration and Production Research Institute, Beijing, 102206, China.Natural fractures are quite important for the high and stable production of tight sandstone gas reservoirs. However, it is commonly difficult to accurately characterize their distribution in tight sandstone gas reservoirs due to the strong heterogeneity. A comprehensive characterization of natural fractures in tight sandstone gas reservoirs of the Xujiahe Formation in the Yuanba area, Sichuan Basin, was carried out by multimethod of core description, log interpretation and seismic prediction. The results show that (1) the natural fractures in the Xujiahe Formation are mainly low-angle fractures, with a few medium- and high-angle fractures. The degree of fracture development is mainly controlled by the distance from the fault, the flexural degree of the strata and the thickness of the rock mechanical layer. (2) The fracture-sensitive seismic attributes such as the preferred maximum likelihood, structure entropy, illuminant-based symmetry and high-precision curvature are taken as the input, and the unsupervised cluster analysis algorithm based on Bayesian probability model is applied to predict the distribution of large-scale fractures at different dip angles; on the basis of narrow azimuthal pre-stack CMP gather optimization, the anisotropy detection technique of Hampson-Russell's ProAZ full CMP gather is used to characterize the distribution of small- and medium-scale fractures, and the predicted fracture development intensity matches the fracture interpretation results of the imaging logs by more than 85%. Moreover, the predicted fracture orientation is basically consistent with that of the imaging loggings. (3) The fault-genesis fractures of the Xujiahe Formation are mainly distributed near the fault on the southeast flank of the Jiulongshan anticline, and are distributed in a narrow strip in NE direction. The fold-genesis fractures are mainly developed in the Xu 3rd Member, and are located in the axis of the Jiulongshan anticline and its southeast flank where the strata are strongly flexed. This study provides a solid foundation for the development of tight sandstone gas reservoirs and extends the approaches for the accurate characterization of fractures.http://www.sciencedirect.com/science/article/pii/S2666519023000080Natural fracturesSeismic properties of fracturesSeismic anisotropyTight sandstoneNorthern sichuan basinUpper triassic |
| spellingShingle | Yanqing Huang Ruyue Wang Characterization of natural fractures in tight sandstone reservoirs in Yuanba area, northern Sichuan Basin Unconventional Resources Natural fractures Seismic properties of fractures Seismic anisotropy Tight sandstone Northern sichuan basin Upper triassic |
| title | Characterization of natural fractures in tight sandstone reservoirs in Yuanba area, northern Sichuan Basin |
| title_full | Characterization of natural fractures in tight sandstone reservoirs in Yuanba area, northern Sichuan Basin |
| title_fullStr | Characterization of natural fractures in tight sandstone reservoirs in Yuanba area, northern Sichuan Basin |
| title_full_unstemmed | Characterization of natural fractures in tight sandstone reservoirs in Yuanba area, northern Sichuan Basin |
| title_short | Characterization of natural fractures in tight sandstone reservoirs in Yuanba area, northern Sichuan Basin |
| title_sort | characterization of natural fractures in tight sandstone reservoirs in yuanba area northern sichuan basin |
| topic | Natural fractures Seismic properties of fractures Seismic anisotropy Tight sandstone Northern sichuan basin Upper triassic |
| url | http://www.sciencedirect.com/science/article/pii/S2666519023000080 |
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