A new method for the characterization of microcracks based on seepage characteristics
Microcracks are the main seepage channels and reservoir space for oil and gas in dense sandstone reservoirs, and the degree of development dominates the reservoir’s high and stable production capacity. A new method has been devised to address the lack of quantitative identification and characterizat...
| Main Authors: | , , , , , , , , , , , |
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| Format: | Article |
| Language: | English |
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Frontiers Media S.A.
2023-07-01
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| Series: | Frontiers in Earth Science |
| Subjects: | |
| Online Access: | https://www.frontiersin.org/articles/10.3389/feart.2023.1229946/full |
| _version_ | 1797778070517579776 |
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| author | Guoying Jiao Feifei Fang Yuanyuan Zhang Zhenkai Wu Jie Zhang Zhenchang Jiang Yingbo Lv Jianqi Cao Jinmei Peng Sijie He Yu Wang Qingtong Guan |
| author_facet | Guoying Jiao Feifei Fang Yuanyuan Zhang Zhenkai Wu Jie Zhang Zhenchang Jiang Yingbo Lv Jianqi Cao Jinmei Peng Sijie He Yu Wang Qingtong Guan |
| author_sort | Guoying Jiao |
| collection | DOAJ |
| description | Microcracks are the main seepage channels and reservoir space for oil and gas in dense sandstone reservoirs, and the degree of development dominates the reservoir’s high and stable production capacity. A new method has been devised to address the lack of quantitative identification and characterization methods for microcrack networks. The method is based on core stress sensitivity, permeability anisotropy, and two-phase seepage rule testing. By improving upon the traditional black oil model, this method can accurately calculate the impact that microcracks of varying degrees of development have on the capacity of tight oil reservoirs. The study shows that 1) the higher the degree of microcrack development, the stronger the reservoir stress sensitivity and the greater the permeability anisotropy. As the degree of microcrack development increases, the irreducible water saturation decreases, the residual oil saturation gradually increases, and the oil–water two-phase co-infiltration zone becomes more extensive and smaller. The degree of microcrack development in tight reservoirs can be characterized based on the seepage characteristic parameters; 2) a microcrack characterization method and classification criteria have been established. It is based on stress sensitivity coefficients, permeability anisotropy parameters, and phase seepage characteristics in cores with different microcrack development degrees. For the first time, the method enables a macroscopic-level description of microcrack seepage; 3) numerical calculations show that the degree of microcrack development significantly affects the reservoir’s oil production and water production. The higher the degree of microcrack development, the higher the reservoir’s initial oil production and cumulative oil production. However, when the degree of microcrack development is too high, the microcracks are connected, thus exhibiting the nature of large fractures. This strengthens the bypassing communication effect and causes the microscopic inhomogeneity to strengthen, the oil production decreases rapidly, and water production increases quickly at the later stage. This research result enriches the reservoir microcrack characterization and evaluation system, which has essential theoretical guidance and practical significance for the rational and effective development of tight oil and tight sandstone gas. |
| first_indexed | 2024-03-12T23:12:02Z |
| format | Article |
| id | doaj.art-ed592f73fc7c403cb690f7f6e43c9d22 |
| institution | Directory Open Access Journal |
| issn | 2296-6463 |
| language | English |
| last_indexed | 2024-03-12T23:12:02Z |
| publishDate | 2023-07-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Earth Science |
| spelling | doaj.art-ed592f73fc7c403cb690f7f6e43c9d222023-07-18T01:05:35ZengFrontiers Media S.A.Frontiers in Earth Science2296-64632023-07-011110.3389/feart.2023.12299461229946A new method for the characterization of microcracks based on seepage characteristicsGuoying Jiao0Feifei Fang1Yuanyuan Zhang2Zhenkai Wu3Jie Zhang4Zhenchang Jiang5Yingbo Lv6Jianqi Cao7Jinmei Peng8Sijie He9Yu Wang10Qingtong Guan11School of Petroleum Engineering, Chongqing University of Science and Technology, Chongqing, ChinaSchool of Petroleum Engineering, Chongqing University of Science and Technology, Chongqing, ChinaResearch Institute of Exploration and Development, PetroChina Changqing Oil Field Company, Xian, Shaanxi, ChinaPetroChina Research Institute of Petroleum Exploration and Development, Beijing, ChinaSchool of Petroleum Engineering, Chongqing University of Science and Technology, Chongqing, ChinaResearch Institute of Exploration and Development, PetroChina Jilin Oilfield Company, Songyuan, Jilin, ChinaFuyu Oil Production Plant, Jilin Oilfield Company, PetroChina Jilin Oilfield Company, Songyuan, Jilin, ChinaSchool of Petroleum Engineering, Chongqing University of Science and Technology, Chongqing, ChinaSchool of Petroleum Engineering, Chongqing University of Science and Technology, Chongqing, ChinaSchool of Petroleum Engineering, Chongqing University of Science and Technology, Chongqing, ChinaSchool of Petroleum Engineering, Chongqing University of Science and Technology, Chongqing, ChinaSchool of Petroleum Engineering, Chongqing University of Science and Technology, Chongqing, ChinaMicrocracks are the main seepage channels and reservoir space for oil and gas in dense sandstone reservoirs, and the degree of development dominates the reservoir’s high and stable production capacity. A new method has been devised to address the lack of quantitative identification and characterization methods for microcrack networks. The method is based on core stress sensitivity, permeability anisotropy, and two-phase seepage rule testing. By improving upon the traditional black oil model, this method can accurately calculate the impact that microcracks of varying degrees of development have on the capacity of tight oil reservoirs. The study shows that 1) the higher the degree of microcrack development, the stronger the reservoir stress sensitivity and the greater the permeability anisotropy. As the degree of microcrack development increases, the irreducible water saturation decreases, the residual oil saturation gradually increases, and the oil–water two-phase co-infiltration zone becomes more extensive and smaller. The degree of microcrack development in tight reservoirs can be characterized based on the seepage characteristic parameters; 2) a microcrack characterization method and classification criteria have been established. It is based on stress sensitivity coefficients, permeability anisotropy parameters, and phase seepage characteristics in cores with different microcrack development degrees. For the first time, the method enables a macroscopic-level description of microcrack seepage; 3) numerical calculations show that the degree of microcrack development significantly affects the reservoir’s oil production and water production. The higher the degree of microcrack development, the higher the reservoir’s initial oil production and cumulative oil production. However, when the degree of microcrack development is too high, the microcracks are connected, thus exhibiting the nature of large fractures. This strengthens the bypassing communication effect and causes the microscopic inhomogeneity to strengthen, the oil production decreases rapidly, and water production increases quickly at the later stage. This research result enriches the reservoir microcrack characterization and evaluation system, which has essential theoretical guidance and practical significance for the rational and effective development of tight oil and tight sandstone gas.https://www.frontiersin.org/articles/10.3389/feart.2023.1229946/fulltight oilmicrocracksseepage characterizationcharacterization methodsrelative permeability curve tight oiloil production |
| spellingShingle | Guoying Jiao Feifei Fang Yuanyuan Zhang Zhenkai Wu Jie Zhang Zhenchang Jiang Yingbo Lv Jianqi Cao Jinmei Peng Sijie He Yu Wang Qingtong Guan A new method for the characterization of microcracks based on seepage characteristics Frontiers in Earth Science tight oil microcracks seepage characterization characterization methods relative permeability curve tight oil oil production |
| title | A new method for the characterization of microcracks based on seepage characteristics |
| title_full | A new method for the characterization of microcracks based on seepage characteristics |
| title_fullStr | A new method for the characterization of microcracks based on seepage characteristics |
| title_full_unstemmed | A new method for the characterization of microcracks based on seepage characteristics |
| title_short | A new method for the characterization of microcracks based on seepage characteristics |
| title_sort | new method for the characterization of microcracks based on seepage characteristics |
| topic | tight oil microcracks seepage characterization characterization methods relative permeability curve tight oil oil production |
| url | https://www.frontiersin.org/articles/10.3389/feart.2023.1229946/full |
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