Fine Logging Evaluation of Fractures in Continental Tight Oil Sandstone Reservoirs of Yanchang Formation in the Ordos Basin
Fractures are the main seepage channels in tight reservoirs, and they affect the distribution of high-quality reservoirs and the enrichment of hydrocarbons. Fine logging identification of fractures in the strongly heterogeneous continental tight oil reservoirs of the Upper Triassic Yanchang Formatio...
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Frontiers Media S.A.
2022-02-01
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| Series: | Frontiers in Earth Science |
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| Online Access: | https://www.frontiersin.org/articles/10.3389/feart.2022.860473/full |
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| author | Zhanjun Chen Anzhao Ji Yidong Yuan Yidong Yuan |
| author_facet | Zhanjun Chen Anzhao Ji Yidong Yuan Yidong Yuan |
| author_sort | Zhanjun Chen |
| collection | DOAJ |
| description | Fractures are the main seepage channels in tight reservoirs, and they affect the distribution of high-quality reservoirs and the enrichment of hydrocarbons. Fine logging identification of fractures in the strongly heterogeneous continental tight oil reservoirs of the Upper Triassic Yanchang Formation in the Ordos Basin is a hot and difficult point in the field of petroleum geology. In this paper, taking the Yanchang Formation as an example, a fractal model was constructed to identify fractures in tight oil reservoirs using a large number of cores, conventional and micro-resistivity imaging logging data. The results show that high-angle, vertical and bedding fractures are mainly developed in the Yanchang Formation tight sandstones. There is a negative correlation between sand body thickness and fracture development degree. The fracture sensitivity parameters were used to construct a coupled fractal fracture index. The fractal model incorporates logging information from natural gamma, acoustic wave time difference, rock density, and shallow lateral resistivity. In addition, the constructed fracture fractal index realizes the functions of multi-conventional logging information fusion, which can effectively identify fracture development segments in sandstone. According to the statistics, the fracture identification rate is 83.3%. The study also found that with the increase of sandstone brittleness index, the fracture index has a “S” shape increasing trend. Therefore, the content of brittle mineral components in sandstone is an important factor affecting the development degree of natural fractures, and fractures are more likely to occur in high brittle, thin sand bodies. The highly brittle framework minerals have strong stress-supporting capacity, which can keep fractures open by resisting high overlying loads. |
| first_indexed | 2024-12-13T01:02:59Z |
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| id | doaj.art-64809863a1ce44f0afb9e0cad7dec29f |
| institution | Directory Open Access Journal |
| issn | 2296-6463 |
| language | English |
| last_indexed | 2024-12-13T01:02:59Z |
| publishDate | 2022-02-01 |
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| series | Frontiers in Earth Science |
| spelling | doaj.art-64809863a1ce44f0afb9e0cad7dec29f2022-12-22T00:04:39ZengFrontiers Media S.A.Frontiers in Earth Science2296-64632022-02-011010.3389/feart.2022.860473860473Fine Logging Evaluation of Fractures in Continental Tight Oil Sandstone Reservoirs of Yanchang Formation in the Ordos BasinZhanjun Chen0Anzhao Ji1Yidong Yuan2Yidong Yuan3School of Energy Engineering, Longdong University, Qingyang, ChinaSchool of Energy Engineering, Longdong University, Qingyang, ChinaSchool of Energy Engineering, Longdong University, Qingyang, ChinaState Key Laboratory of Continental Dynamics, Northwest University, Xi’an, ChinaFractures are the main seepage channels in tight reservoirs, and they affect the distribution of high-quality reservoirs and the enrichment of hydrocarbons. Fine logging identification of fractures in the strongly heterogeneous continental tight oil reservoirs of the Upper Triassic Yanchang Formation in the Ordos Basin is a hot and difficult point in the field of petroleum geology. In this paper, taking the Yanchang Formation as an example, a fractal model was constructed to identify fractures in tight oil reservoirs using a large number of cores, conventional and micro-resistivity imaging logging data. The results show that high-angle, vertical and bedding fractures are mainly developed in the Yanchang Formation tight sandstones. There is a negative correlation between sand body thickness and fracture development degree. The fracture sensitivity parameters were used to construct a coupled fractal fracture index. The fractal model incorporates logging information from natural gamma, acoustic wave time difference, rock density, and shallow lateral resistivity. In addition, the constructed fracture fractal index realizes the functions of multi-conventional logging information fusion, which can effectively identify fracture development segments in sandstone. According to the statistics, the fracture identification rate is 83.3%. The study also found that with the increase of sandstone brittleness index, the fracture index has a “S” shape increasing trend. Therefore, the content of brittle mineral components in sandstone is an important factor affecting the development degree of natural fractures, and fractures are more likely to occur in high brittle, thin sand bodies. The highly brittle framework minerals have strong stress-supporting capacity, which can keep fractures open by resisting high overlying loads.https://www.frontiersin.org/articles/10.3389/feart.2022.860473/fullordos basinyanchang formationtight oil reservoirsfractureslogging evaluation |
| spellingShingle | Zhanjun Chen Anzhao Ji Yidong Yuan Yidong Yuan Fine Logging Evaluation of Fractures in Continental Tight Oil Sandstone Reservoirs of Yanchang Formation in the Ordos Basin Frontiers in Earth Science ordos basin yanchang formation tight oil reservoirs fractures logging evaluation |
| title | Fine Logging Evaluation of Fractures in Continental Tight Oil Sandstone Reservoirs of Yanchang Formation in the Ordos Basin |
| title_full | Fine Logging Evaluation of Fractures in Continental Tight Oil Sandstone Reservoirs of Yanchang Formation in the Ordos Basin |
| title_fullStr | Fine Logging Evaluation of Fractures in Continental Tight Oil Sandstone Reservoirs of Yanchang Formation in the Ordos Basin |
| title_full_unstemmed | Fine Logging Evaluation of Fractures in Continental Tight Oil Sandstone Reservoirs of Yanchang Formation in the Ordos Basin |
| title_short | Fine Logging Evaluation of Fractures in Continental Tight Oil Sandstone Reservoirs of Yanchang Formation in the Ordos Basin |
| title_sort | fine logging evaluation of fractures in continental tight oil sandstone reservoirs of yanchang formation in the ordos basin |
| topic | ordos basin yanchang formation tight oil reservoirs fractures logging evaluation |
| url | https://www.frontiersin.org/articles/10.3389/feart.2022.860473/full |
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