The feasibility of marine CSEM method for detecting offshore freshened groundwater reservoirs

WU Xiaoting; LI Yuguo; DUAN Shuangmin

doi:10.16562/j.cnki.0256-1492.2023071902

Marine Geology & Quaternary Geology > 2024 > 44(6): 204-215. > DOI: 10.16562/j.cnki.0256-1492.2023071902

WU Xiaoting，LI Yuguo，DUAN Shuangmin. The feasibility of marine CSEM method for detecting offshore freshened groundwater reservoirs[J]. Marine Geology & Quaternary Geology，2024，44(6)：204-215. DOI: 10.16562/j.cnki.0256-1492.2023071902

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The feasibility of marine CSEM method for detecting offshore freshened groundwater reservoirs

1.
College of marine geosciences, Ocean University of China, Qingdao 266100, China
2.
National Engineering Research Center of Offshore Oil and Gas Exploration, Beijing 100000, China

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Received Date: July 18, 2023
Revised Date: October 31, 2023

Graphical Abstract

Abstract

Abstract

Offshore freshened groundwater (OFG) is a natural freshwater resource located mainly in the continental shelf region, from either onshore coastal aquifers or paleo-channels formed in sea-level lowstands. Conventional seismic methods have certain limitations in identifying salinity changes. Fortunately, the marine CSEM (controlled source electromagnetic method) is sensitive to high-resistivity thin layers, which is beneficial for detection of OFG by analyzing electromagnetic anomalies caused by the contrast of resistivity between the freshwater reservoirs and surrounding sediments. Paleo-channels in Shengsi in the Yangtze River estuary were studied. Based on the hydrogeological and logging data of "Shengsi No. 1 Well", a geoelectric model was established to analyze the marine CSEM responses. Results indicate that the marine CSEM could effectively detect electromagnetic anomalies caused by high-resistivity thin layers, and has good ability to locate underground freshwater reservoirs; its application for the detection of OFG in the Shengsi paleo-channel is feasible.
- marine CSEM,
- OFG,
- detectivity,
- Shengsi

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References (32)

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