NATURAL GAS MODELS CONTROLLED BY GRADED MULTI-FACTORS IN MARINE SEQUENCES OF SOUTH CHINA

Having multiple stages of tectonic events,most of marine petroleum reservoirs in South China belong to secondary petroleum reservoirs.The reformation and distribution of petroleum reservoirs were mainly controlled by graded pool-controlling factors.The first grade of pool-controlling factors were the pool fluid sources,the second grade were the periods of petroleum formation and reconstruction,and the third included preservation condition and trap types.Ten types of pool-controlling models were set up based on the first two grades of pool-controlling factors in South China.Four of them,including primary source primary accumulation,secondly source primary accumulation, inorganic source primary accumulation and mixed source secondary accumulation,have been confirmed by exploration,named as type Well Mian 31,type Zhujiadun,type Huangqiao,and type Sichuan by known cases.The distribution map of eight typical pools models based on first three grades of pool-controlling factors supports that type Sichuan distribute mainly in Upper Yangtze Block,type Well Mian 31 mainly in margin of Jiannan Uplift,type Zhujiadun in Middle and Lower Yangtze Block,and type Huangqiao mainly in tensional structural area.