Characteristics and reservoir control effects of the fault system in Kongqueting area of Xihu Sag,East China Sea Basin
Based on the fine interpretation of 3D seismic data,the characteristics of the fault system in Kongqueting area of Xihu Sag in the East China Sea Basin were analyzed using methods such as structural profile reconstruc-tion and fluid inclusion analysis.The evolution characteristics and reservoir control effects were studied.The results show that:(1)The fault system in Kongqueting District of Xihu Sag has obvious differences in east and west zoning,and showing different zoning.On the plane,there are three sets of main extensional faults devel-oped in the east,mainly in the NNE direction,followed by the NE direction and near NS direction,and two sets of main extensional faults developed in the west,mainly in the NE direction,followed by the NNE direction;On the profile,the eastern part is dominated by a domino shaped oblique structure style,while the western part is dominated by syndromic fault terraces;From west to east,it can be divided into 5 fault zones,with 2 reverse fault zones developed in the east and 3 syndromic fault zones developed in the west.(2)The fault system in the research area has gone through four evolutionary stages:fault depression period,fault depression conversion period,depression inversion period,and regional subsidence period.The fault activity shows differential evolu-tion characteristics of"early strong and late weak in the east,early weak and late strong in the west".(3)The research area has developed reverse fault groove-local self enclosed oil and gas reservoir in the east,as well as forward fault terraces and lithological pinch out oil and gas reservoirs in the west.The reservoirs in the east are dual source hydrocarbon supply,which are favorable for oil and gas accumulation zone.Especially,the F2 and F3 faults have strong activity,large fault displacement,large controlled trap area and height.They are rich in oil in the Pinghu Formation and rich in gas in the lower section of the Huagang Formation,making them favorable exploration areas.
extensional fracturefracture activitydual source hydrocarbon supplyfracture controlled storagereverse fault groove-local self enclosed oil and gas reservoirforward fault terraces and lithological pinch out oil and gas reservoirXihu SagEast China Sea