CHARACTERISTICS OF FLUID INCLUSIONS IN THE SHIWANDASHAN BASIN OF GUANGXI PROVINCE AND ITS APPLICATION IN PETROLEUM GEOLOGY

For quantitative evaluation of oil and gas resources of the Lower Triassic,the Permian and the Devonian strata for main source and reservoir beds, the fluid inclusion studies was carried out. The results demonstrated that the fluid inclusions trapped in the rocks can be assigned to seven stages in corresponding to different deposition-diagenesis-tectonic stages. Moreover, the thermodynamic parameters of oil and gas with relation to formation environment in the different stages herein be presented, and the history of generation-migration-accumulation of oil and gas in two areas be analyzed. The concerned evidence shows that the primary oil migration was related to the abnormal pressure. While the multiple oil migration to the tectonic movements, the main channels of oil-gas migration were tectonic fractures. The fluids containing oil and gas can be considered as the multiphase immiscible fluid. The data available can be summarized as: the Lower Triassic strata are the best oil-source rocks, and the Devonian strata belong to the gas-source rocks in this region. In addition, the pyroclastic rocks in the north of the region has a positive influence on the generation and evolution of oil and gas, and the granites occurred in the southeast has no affect on the oil and gas pools formation.