Research On Faults Sealing In Majiazui District,Gaoyou Sag

Many fault blocks have been found rich in oil and gas in recent years,and it is obviously that oil and gas distribute along Hanliu fault belt.Fault sealing is an important factor that affect hydrocarbon accumulation.In order to find favorable block of fault sealing and petroleum accumulation and predict further exploration direction,it is important to research on the sealing of the faults in Majiazui area.With the aid of geology,seismic,logging data,we evaluated sealing ability of six faults in this area from the qualitative and quantitative aspects respectively.On this basis,affecting factors can be quantitatively characterized,then the thesis used fuzzy comprehensive assessment to estimate fault sealing.Combining with model of petroleum transportation,we explained the internal relationship between fault sealing and hydrocarbon accumulation.According to the fault sealing evaluation results,control action of faults during the formation of hydrocarbon accumulations was comprehensive evaluated.Finally,we analyzed the feasibility of fault sealing evaluation method and result based on the exploration situation.Research on the vertical and lateral seal characteristics of the fault by studying the influencing factor,such as net-to-gross ratio,shale gouge ratio,shaliness in fault zone,normal stress of fault plane and tightness index.The evaluation result shows that the sealing ability gradually increased from Sanduo formation to Funing formation in the whole area.The fourth member of Funing formation marine source rock is the most favorable one in the Majiazui area,so the the first member of Dainan formation is the most favorable one to accumulating oil and gas.The result indicates that fault sealing ability of E₂d₁ is good,it can form reservoir efficiently.In plane view,the fault contained two fault strike of NNE and NNW where the oil and gas transport during periods of fault activities.The fault sealing ability is good at the interface of han 1 fault and ma 33 fault,which is also the interface of the two fault strike.Meanwhile,it is the accumulation area of two hydrocarbon migration direction that is favorable for hydrocarbon accumulation and potential for exploration.The results of the study area not only have theoretic importance and practical value,but also have important guiding significance to other parts of the relevant research.