Abstract:

Based on the theory of gas hydrate geological system, gas hydrate accumulation conditions of Shenhu prospect are studied. The results indicate that there are excellent gaseous hydrocarbon source sub-system and gas-bearing fluid migration subsystem. The gas hydrate in this area is proved to be a mixture of biogenic gas and thermogenic gas and the hydrocarbon potential of the source rock is high; faults, gas chimneys, and detachment surface constitute the dominant migration pathway for the hydrocarbon to migrate horizontally and vertically. Geothermal characteristic and gas hydrate reservoir accumulation subsystem (characteristics of lithology and lithological assemblage) are the main reason why gas hydrate is distributed heterogeneously in all spatial scales in the study area. The lower the temperature of the earth and the geothermal gradient, the coarser the sediment grain is. In addition, the fine-above-coarse-below lithological assemblage is more beneficial for the gas hydrate to accumulate.

Key words: natural gas hydrate, geological system, reservoir accumulation sub-system, Shenhu prospect