Source-Reservoir Characteristics and Accumulation of Gas Chimney-Type Gas Hydrates in Qiongdongnan Basin, Northern South China Sea

The Qiongdongnan Basin is an important gas hydrate exploration area in the South China Sea, but accumulation process poorly understood. By selecting Lingshui (LS) target and using first-hand geochemical data, three-dimensional seismic independent thermal insulation pressure maintaining shipborne core analysis system, this study, comprehensive geological evaluation was carefully conducted around source reservoir of chimney hydrates, investigated. Geochemical data for a total 47 sets samples revealed that hydrates study mainly thermogenic supplemented by mixed gas. It predicted contribution to up 70%. Using characteristics low-temperature combustible were determined, characterized as non-diagenetic weakly diagenetic, rich clay silt (D50 = 15.1–34.1 ?m), self-sustaining, strongly heterogeneous. Based on differentiated response layer-gas bearing layer-shallow layer at top chimney, determined be follows: remote transportation, local microbial genetic accumulation, episodic dynamic formation, source-reservoir control. In addition, ideas effective supply from shallow large-scale sand body are emphasized. results provide reference trial production natural Sea.