Controlling Factors of Hydrocarbon Differential Enrichment In W Structure of Weixi Exploratory Area

Drilling reveals that hydrocarbon enrichment in different fault blocks and horizons of Weixi exploration area W structure is obviously different, but the controlling factors are unknown. In order to clarify the controlling factors of the differential enrichment of hydrocarbon in this structure, the key accumulation factors of different fault blocks were studied and compared in detail. On the premise of clarifying the oil source and accumulation period, the control action of migration system and preservation conditions on differential enrichment was studied. The results show that hydrocarbons of W structure have the same source and the same petroleum accumulation period which is after the Middle Miocene. The differential enrichment of hydrocarbon is mainly controlled by oil and gas dredging and fault sealing. W3Ⅱand W3Ⅲ sand groups are the advantage sandstone conductive layers under the regional mudstone cap rock, which is the premise of hydrocarbon enrichment. The relationship between the dominant sandstone carrier layer and the oil source fault and the distribution of the regional cap rock are the main controlling factors of the differential enrichment of oil and gas on the plane. The development degree of the direct cap rock is the main controlling factor of the differential enrichment of oil and gas along the fault in the vertical direction. The research results have reference significance for the next hydrocarbon exploration in W structure of Weixi exploratory area.