Fluid Identification Based on NMR Apparent Free Water Porosity Inversion: A Case Study of Paleozoic Tight Sandstone Gas Reservoirs in Western Ordos
Tight sandstone reservoirs are affected by various factors such as pore structure, formation water salinity, and siliceous cementation, which lead to the abnormal phenomenon of high-resistivity water layers and increase the difficulty in identifying gas and water layers by conventional logging. In t...
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| Format: | Article |
| Language: | English |
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Wiley
2022-01-01
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| Series: | Geofluids |
| Online Access: | http://dx.doi.org/10.1155/2022/4193773 |
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| author | Fuqiang Lai Yuejiao Liu Xiaopan Kou Zhaohui Huang Zhen Chen Yuanqi Liu Guoqiang Jiang Yongqian Zang Min Wang Ruyue Wang |
| author_facet | Fuqiang Lai Yuejiao Liu Xiaopan Kou Zhaohui Huang Zhen Chen Yuanqi Liu Guoqiang Jiang Yongqian Zang Min Wang Ruyue Wang |
| author_sort | Fuqiang Lai |
| collection | DOAJ |
| description | Tight sandstone reservoirs are affected by various factors such as pore structure, formation water salinity, and siliceous cementation, which lead to the abnormal phenomenon of high-resistivity water layers and increase the difficulty in identifying gas and water layers by conventional logging. In this study, the pore types and pore size distribution characteristics of tight sandstone reservoirs were firstly determined by NMR and high-pressure mercury injection experiments, and then the iterative least-square method was used to automatically optimize the inversion method of pseudo-capillary pressure curve and search for the optimal conversion coefficient. Finally, the apparent free water porosity was inversed and the fluid identification standard was obtained and applied. The results showed that the reservoirs mainly developed intergranular pores, cutting solution pores, and intergranular pores. The pore throats were poorly sorted, and the displacement pressure was high. The median radius ranged from 0.01 to 0.48 μm, and the main peak range was from 0.02 to 0.06 μm. Pores were of mainly small-hole fine throat type. In the inversion results of the optimal conversion coefficient, the correlation coefficient between the aperture parameters and the results of high-pressure mercury injection experiments was greater than 0.93. According to the fluid property identification standard based on nuclear magnetic apparent free water porosity, the high-resistivity water layers were effectively identified and its coincidence rate with the final field test was 10.7% higher than that of the conventional method. This identification method can be used to identify complex fluids in tight sandstone reservoirs. |
| format | Article |
| id | doaj-art-e76ea2e402b142ccb2340b7e64ef00b1 |
| institution | Kabale University |
| issn | 1468-8123 |
| language | English |
| publishDate | 2022-01-01 |
| publisher | Wiley |
| record_format | Article |
| series | Geofluids |
| spelling | doaj-art-e76ea2e402b142ccb2340b7e64ef00b12025-02-03T01:10:37ZengWileyGeofluids1468-81232022-01-01202210.1155/2022/4193773Fluid Identification Based on NMR Apparent Free Water Porosity Inversion: A Case Study of Paleozoic Tight Sandstone Gas Reservoirs in Western OrdosFuqiang Lai0Yuejiao Liu1Xiaopan Kou2Zhaohui Huang3Zhen Chen4Yuanqi Liu5Guoqiang Jiang6Yongqian Zang7Min Wang8Ruyue Wang9Chongqing Key Laboratory of Complex Oilfield Exploration and DevelopmentChongqing Key Laboratory of Complex Oilfield Exploration and DevelopmentExploration and Development Research Institute of Changqing Oilfield CompanyChongqing Key Laboratory of Complex Oilfield Exploration and DevelopmentExploration and Development Research Institute of Changqing Oilfield CompanyChongqing Key Laboratory of Complex Oilfield Exploration and DevelopmentChongqing Key Laboratory of Complex Oilfield Exploration and DevelopmentChongqing Key Laboratory of Complex Oilfield Exploration and DevelopmentSINOPEC Exploration and Development Research Institute of Shengli Oilfield CompanySINOPEC Petroleum Exploration and Production Research InstituteTight sandstone reservoirs are affected by various factors such as pore structure, formation water salinity, and siliceous cementation, which lead to the abnormal phenomenon of high-resistivity water layers and increase the difficulty in identifying gas and water layers by conventional logging. In this study, the pore types and pore size distribution characteristics of tight sandstone reservoirs were firstly determined by NMR and high-pressure mercury injection experiments, and then the iterative least-square method was used to automatically optimize the inversion method of pseudo-capillary pressure curve and search for the optimal conversion coefficient. Finally, the apparent free water porosity was inversed and the fluid identification standard was obtained and applied. The results showed that the reservoirs mainly developed intergranular pores, cutting solution pores, and intergranular pores. The pore throats were poorly sorted, and the displacement pressure was high. The median radius ranged from 0.01 to 0.48 μm, and the main peak range was from 0.02 to 0.06 μm. Pores were of mainly small-hole fine throat type. In the inversion results of the optimal conversion coefficient, the correlation coefficient between the aperture parameters and the results of high-pressure mercury injection experiments was greater than 0.93. According to the fluid property identification standard based on nuclear magnetic apparent free water porosity, the high-resistivity water layers were effectively identified and its coincidence rate with the final field test was 10.7% higher than that of the conventional method. This identification method can be used to identify complex fluids in tight sandstone reservoirs.http://dx.doi.org/10.1155/2022/4193773 |
| spellingShingle | Fuqiang Lai Yuejiao Liu Xiaopan Kou Zhaohui Huang Zhen Chen Yuanqi Liu Guoqiang Jiang Yongqian Zang Min Wang Ruyue Wang Fluid Identification Based on NMR Apparent Free Water Porosity Inversion: A Case Study of Paleozoic Tight Sandstone Gas Reservoirs in Western Ordos Geofluids |
| title | Fluid Identification Based on NMR Apparent Free Water Porosity Inversion: A Case Study of Paleozoic Tight Sandstone Gas Reservoirs in Western Ordos |
| title_full | Fluid Identification Based on NMR Apparent Free Water Porosity Inversion: A Case Study of Paleozoic Tight Sandstone Gas Reservoirs in Western Ordos |
| title_fullStr | Fluid Identification Based on NMR Apparent Free Water Porosity Inversion: A Case Study of Paleozoic Tight Sandstone Gas Reservoirs in Western Ordos |
| title_full_unstemmed | Fluid Identification Based on NMR Apparent Free Water Porosity Inversion: A Case Study of Paleozoic Tight Sandstone Gas Reservoirs in Western Ordos |
| title_short | Fluid Identification Based on NMR Apparent Free Water Porosity Inversion: A Case Study of Paleozoic Tight Sandstone Gas Reservoirs in Western Ordos |
| title_sort | fluid identification based on nmr apparent free water porosity inversion a case study of paleozoic tight sandstone gas reservoirs in western ordos |
| url | http://dx.doi.org/10.1155/2022/4193773 |
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