Focused Fluid Flow, Shallow Gas Hydrate, and Cold Seep in the Qiongdongnan Basin, Northwestern South China Sea

The 3D seismic data acquired in the central Qiongdongnan Basin, northwestern South China Sea, reveal presence of shallow gas hydrate, free gas, and focused fluid flow study area, which are indicated by multiple anomalies, including bottom simulating reflectors, polarity reverses, pulldowns, minor faults, chimneys intensively emplaced within strata. A new cold seep is also discovered at approximately 1520 m water depths with an ~40 wide crater west part area. Water column imaging, seafloor observation, sampling using remotely operated vehicle “Haima” demonstrate ongoing seepages hydrates this site. Thermogenic area migrates from deep reservoir through hydrate stability zone along faults chimneys, forms sustains localized seepage seep. results provide insight into relationship between accumulation hydrocarbon generation migration simultaneously have important implications for explorations Sea.