Abstract:

 In order to understand the main controlling factors of gas hydrate occurrences in the X Block of Shenhu area, South China Sea, the fine seismic explanations and seismic facies studies of gas hydrate were carried out. The results show that there exist three important faults and lots of collapse structures, multilayer hydratebearing sediments exist in the gas hydrate stable zone, which have big thickness and good continuity in the base of the gas hydrate stable zone. In combination with seismic reflection features and probable gas resource discussion, it is concluded that there probably exist two kinds of reservoir models in the X Block. In the areas where faults or collapse structures develop, the gas resource is probably composed of thermogenic gas, gas hydrate is characterized by multilayer distribution, while in the inactive areas the gas resource is probably composed of biogenic gas, and gas hydrate is characterized by monolayer, which mainly distributes in a narrow zone on the surface of BSR(bottomsimulating seismic reflector).

Key words: controlling factor, reservoir model, gas hydrate, X Block, Shenhu area, South China Sea