Characters of North-West Mud Diapirs Volcanoes in South China Sea and Relationship between Them and Accumulation and Migration of Oil and Gas

It has geological and mode of occurrence differences between mud diapirs and mud volcanoes though the similar genesis and the characters of evolution and development. Mud diapirs in Yinggehai basin located in the central deep depression, appeared on five north-west lines and had characters of low density, low wave velocity, high temperature and high pressure however mud volcanoes in Southwest Taiwan basin located in the continental deep-water distract in the south depression and Tainan-Kaohsiung distract in Taiwan. It located along the discordogenic fault and usually had calderas also sea floors. Mud diapirs and mud volcanoes had many styles of accompanying gas to be mainly of the mature-post mature coaliferous gas and had abundence CO2 and N2 to be mainly of the inorganic-crustal CO2. The mud formations were Miocene and Pliocene marine mud shales which was souce rocks, furthermore it made a effictive system with the channel and affiliated structures generated by mud diapirs and mud volcanoes, so it was a particular petroleum system controlling the distribution of oil and gas.