CONTROLLING FACTORS FOR GAS ACCUMULATION IN KONGQUETING GAS FIELD OF XIHU SAG

Based upon the integration of geological, drilling, biomarkers, carbon isotope, fluid inclusion data and the analyses of the oil and gas distribution pattern and the sources of oil and gas, the controlling factors for hydrocarbon accumulation in the Kongqueting gas field are discussed. Research results show that the oil and gas are mainly distributed in the Eocene Pinghu Formation, in a vertical pattern with oil lying upon gas. It is mainly a block-type condensate gas reservoir. Oil and gas are mainly contributed by both the local deposits and the deposits in the western sub-depression of the Pinghu Depression. The accumulation of oil and gas is mainly controlled by fault sealing, changes in sand body thickness and reservoir property and fluid filling history. The fault block controls the sealing condition of the reservoir, sand body thickness and reservoir properties restrict the oil and gas saturation, and the fluid filling history determines the current phase occurrence of oil and gas.