Abstract:

Based on the seismic profile data of Dongsha of the South China Sea, using a twodimensional simulation software, Basin2, combining with the data of the geothermal field, heat flow and core of leg 184  of ODP,this paper rebuilt the subsidence history of the study area, the hydrocarbongenerating history of the organic matter, and the change history of the ancient geothermal field and thermal.The paper simulated the process of hydrate accumulation and distribution with “Biogenic Gas Hydrate Reservoir Dynamics Simulation System”(Hydrate Dynamics). Simulation results show that the thickness of the hydrate stability region is large (200~250 m), and organic matter content is moderate, biogenic methane is generated 1 000 mbsf. Biogenic methane generated by the organic matter in the sediments buried previously under the stability region can migrate and accumulate in the shallow strata because of the compaction flow, and contribute to the current mineral deposit. Hydrates occur in the stable region mainly for the thickness of 50 m, and average saturation of hydrate is about 5%.

Key words: gas hydrate;reservoir dynamic;Basin2 twodimensional simulation software, Dongsha area, South China sea