Shallow Overpressure Formation in the Deep Water Area of the Qiongdongnan Basin, China
The scarcity of drilling in the deep water area of Qiongdongnan Basin restricts the cognition and prediction of overpressure. In this paper, a shallow zone of overpressure at the depth of 900–1,200 m below the sea floor in the deep water area was found by analyzing electronic logs, mud pressure (Mud...
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Frontiers Media S.A.
2022-07-01
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| Series: | Frontiers in Earth Science |
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| Online Access: | https://www.frontiersin.org/articles/10.3389/feart.2022.922802/full |
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| author | Jinfeng Ren Jinfeng Ren Litao Xu Litao Xu Wanzhong Shi Wanzhong Shi Wei Yang Wei Yang Ren Wang Ren Wang Yulin He Yulin He Hao Du Hao Du |
| author_facet | Jinfeng Ren Jinfeng Ren Litao Xu Litao Xu Wanzhong Shi Wanzhong Shi Wei Yang Wei Yang Ren Wang Ren Wang Yulin He Yulin He Hao Du Hao Du |
| author_sort | Jinfeng Ren |
| collection | DOAJ |
| description | The scarcity of drilling in the deep water area of Qiongdongnan Basin restricts the cognition and prediction of overpressure. In this paper, a shallow zone of overpressure at the depth of 900–1,200 m below the sea floor in the deep water area was found by analyzing electronic logs, mud pressure (Mud pressure is a product of the height of the column of mud, density and gravity acceleration) and test pressure from drill stem testing (DST) and modular dynamic testing (MDT), and the interpretation of anomalous seismic interval velocities. The shallow overpressure is a newly observed geological phenomenon in the South China Sea for which the generation mechanisms are not well understood, despite similar observations and analyses elsewhere in the world. Two representative wells, one each located in the shallow water and the deep water areas, respectively were selected to investigate the vertical distribution of the shallow overpressure. The top of the overpressure in Well A in the shallow water area is about 2,111 m below sea floor, while the top of the overpressure in Well B in the deep water area is about 1,077 m below sea floor. A pressure coefficient (i.e., ratio of pore pressure to the normal hydrostatic pressure measured from the sea surface) profile was constructed from the shallow water area to the deep water area using the calibrated relationship between seismic interval velocities and pressure data from 30 wells. The distance between the top of the overpressure and the seabed is predicted to be between 900 and 1,200 m in the deep water area Basin. Disequilibrium compaction is the interpreted primary cause of the shallow overpressure and the results of basin modeling indicate that the shallow overpressure was generated since 5.5 Ma. |
| first_indexed | 2024-12-11T03:31:29Z |
| format | Article |
| id | doaj.art-45e846b466b04582847634f570a90896 |
| institution | Directory Open Access Journal |
| issn | 2296-6463 |
| language | English |
| last_indexed | 2024-12-11T03:31:29Z |
| publishDate | 2022-07-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Earth Science |
| spelling | doaj.art-45e846b466b04582847634f570a908962022-12-22T01:22:23ZengFrontiers Media S.A.Frontiers in Earth Science2296-64632022-07-011010.3389/feart.2022.922802922802Shallow Overpressure Formation in the Deep Water Area of the Qiongdongnan Basin, ChinaJinfeng Ren0Jinfeng Ren1Litao Xu2Litao Xu3Wanzhong Shi4Wanzhong Shi5Wei Yang6Wei Yang7Ren Wang8Ren Wang9Yulin He10Yulin He11Hao Du12Hao Du13Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou, ChinaNational Engineering Research Center of Gas Hydrate Exploration and Development, Guangzhou Marine Geological Survey, Guangzhou, ChinaKey Laboratory of Tectonics and Petroleum Resources, The Ministry of Education, China University of Geosciences, Wuhan, ChinaSchool of Earth Resources, China University of Geosciences, Wuhan, ChinaKey Laboratory of Tectonics and Petroleum Resources, The Ministry of Education, China University of Geosciences, Wuhan, ChinaSchool of Earth Resources, China University of Geosciences, Wuhan, ChinaSouthern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou, ChinaNational Engineering Research Center of Gas Hydrate Exploration and Development, Guangzhou Marine Geological Survey, Guangzhou, ChinaKey Laboratory of Tectonics and Petroleum Resources, The Ministry of Education, China University of Geosciences, Wuhan, ChinaSchool of Earth Resources, China University of Geosciences, Wuhan, ChinaSouthern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou, ChinaNational Engineering Research Center of Gas Hydrate Exploration and Development, Guangzhou Marine Geological Survey, Guangzhou, ChinaKey Laboratory of Tectonics and Petroleum Resources, The Ministry of Education, China University of Geosciences, Wuhan, ChinaSchool of Earth Resources, China University of Geosciences, Wuhan, ChinaThe scarcity of drilling in the deep water area of Qiongdongnan Basin restricts the cognition and prediction of overpressure. In this paper, a shallow zone of overpressure at the depth of 900–1,200 m below the sea floor in the deep water area was found by analyzing electronic logs, mud pressure (Mud pressure is a product of the height of the column of mud, density and gravity acceleration) and test pressure from drill stem testing (DST) and modular dynamic testing (MDT), and the interpretation of anomalous seismic interval velocities. The shallow overpressure is a newly observed geological phenomenon in the South China Sea for which the generation mechanisms are not well understood, despite similar observations and analyses elsewhere in the world. Two representative wells, one each located in the shallow water and the deep water areas, respectively were selected to investigate the vertical distribution of the shallow overpressure. The top of the overpressure in Well A in the shallow water area is about 2,111 m below sea floor, while the top of the overpressure in Well B in the deep water area is about 1,077 m below sea floor. A pressure coefficient (i.e., ratio of pore pressure to the normal hydrostatic pressure measured from the sea surface) profile was constructed from the shallow water area to the deep water area using the calibrated relationship between seismic interval velocities and pressure data from 30 wells. The distance between the top of the overpressure and the seabed is predicted to be between 900 and 1,200 m in the deep water area Basin. Disequilibrium compaction is the interpreted primary cause of the shallow overpressure and the results of basin modeling indicate that the shallow overpressure was generated since 5.5 Ma.https://www.frontiersin.org/articles/10.3389/feart.2022.922802/fullshallow overpressureoverpressure predictionoverpressure distributiongeneration mechanismbasin modelingdeep water area |
| spellingShingle | Jinfeng Ren Jinfeng Ren Litao Xu Litao Xu Wanzhong Shi Wanzhong Shi Wei Yang Wei Yang Ren Wang Ren Wang Yulin He Yulin He Hao Du Hao Du Shallow Overpressure Formation in the Deep Water Area of the Qiongdongnan Basin, China Frontiers in Earth Science shallow overpressure overpressure prediction overpressure distribution generation mechanism basin modeling deep water area |
| title | Shallow Overpressure Formation in the Deep Water Area of the Qiongdongnan Basin, China |
| title_full | Shallow Overpressure Formation in the Deep Water Area of the Qiongdongnan Basin, China |
| title_fullStr | Shallow Overpressure Formation in the Deep Water Area of the Qiongdongnan Basin, China |
| title_full_unstemmed | Shallow Overpressure Formation in the Deep Water Area of the Qiongdongnan Basin, China |
| title_short | Shallow Overpressure Formation in the Deep Water Area of the Qiongdongnan Basin, China |
| title_sort | shallow overpressure formation in the deep water area of the qiongdongnan basin china |
| topic | shallow overpressure overpressure prediction overpressure distribution generation mechanism basin modeling deep water area |
| url | https://www.frontiersin.org/articles/10.3389/feart.2022.922802/full |
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