Characteristics of free gas transport system in Shenhu area of the SCS

Abstract The natural gas hydrate deposit area in the Shenhu area in north of the South China Sea (SCS) is an important position to carry out research on hydrate exploration and development. Strengthening the understanding of the gas hydrate accumulation and migration system in the Shenhu area will help to scientifically evaluate and guide the hydrate resource potential and exploration work in this area. Based on the space time slice analysis of coherent and instantaneous frequency attribute, the distribution position and importance of the two NWW-SEE deep faults and the splitting structure of SW direction angle are clarified; Two types of natural gas migration models in the study area are constructed: the deep fault control type and the splitting control type; The deep gas diffusion vortex is found, and it is inferred that there is a deep gas source between the two fault layers. It is clear that there are three migration modes of natural gas in the study area: free gas phase diffusion, water-soluble gas phase migration with water medium and buoyancy of independent gas phase; and the migration path and mode of natural gas was proposed in the study area.