| The practice of oil and gas exploration shows that in petroliferous basins,there will be oil and gas distribution above the closed fault cap configuration.The oil and gas under the non closed fault cap configuration is more enriched than the oil and gas above it,which is inconsistent with the relationship between sealing and oil and gas distribution of the conventional fault cap configuration.This is mainly because the vertical distribution of oil and gas is not completely affected by whether the current fault cap configuration is closed,Moreover,it should also be affected by whether the fault cap configuration is closed during the oil and gas accumulation period.More importantly,it should be affected by the distribution of the closed evolution form of the fault cap configuration.Only if it is located in the distribution area of the closed evolution form of the fault cap configuration,which is conducive to the accumulation and preservation of oil and gas,can oil and gas accumulate into reservoirs and be discovered by oil and gas drilling;Otherwise,no oil and gas or less oil and gas are found.Therefore,based on the school enterprise cooperation project "Research on the formation and evolution of faults and reservoir control in Dagang Exploration Area" of Petro China Dagang Oilfield Company,this paper selects Banqiao Beidagang area as the research target area,and uses the existing geological,geochemical,seismic,logging,logging,testing and oil testing data in the study area,on the basis of the research on the development and distribution of fault cap configuration in the Shayixia sub member,First,through the prediction of the closed area and the unsealed area of the fault cap configuration in the lower Shahejie formation at present and during the oil and gas accumulation period,then the distribution area of the sealing evolution form of the fault cap configuration in the lower Shahejie formation is predicted by combining the two.Finally,combined with the oil and gas distribution,the control effect of the sealing evolution form distribution of the fault cap configuration in the lower Shahejie formation on the oil and gas distribution in the lower Shahejie formation is expounded.The achievements and understandings obtained in this study mainly include the following five aspects:(1)the distribution area of fault sealing mechanism in Banqiao Beidagang area is mainly in the East and a small amount in the south of Banqiao Beidagang area,and the distribution area of fault sealing mechanism in Banqiao Beidagang area and the brittle plastic regional mudstone caprock configuration in Sha Central Asia is mainly in the East,and the rest of the area is the distribution area of mudstone sealing mechanism in Banqiao Beidagang area;The distribution area of fault sealing mechanism is mainly in the middle part,with a small amount in the south.The rest of the areas are the distribution area of fault sealing mechanism and brittle plastic regional mudstone caprock in SHA-1 Middle Asia.(2)The current fault cover configuration of the Shayixia sub member in Banqiao Beidagang area is mudstone enclosed area in most areas except the northwest and northeast parts;The fault sealing area of the current fault cap configuration in the lower Shahejie sub member is mainly distributed in the middle,with a small amount distributed in the south;The fault unsealed area is mainly distributed in the East.(3)In Banqiao Beidagang area,the fault cap configuration in the oil and gas accumulation period of the Shayixia sub member is mudstone closed area except for the northwest and northeast parts;The fault cap configuration in the oil and gas accumulation period of the lower Shahejie sub member is mainly distributed in the central and southern regions.(4)In Banqiao Beidagang area,there are 8 types of sealing evolution of the fault cap configuration of the Shayixia sub member.Except for the northwest and northeast parts,the mudstone sealing evolution forms are distributed throughout the region;The evolution form of mudstone caprock not closed is only distributed in some parts of Northeast China;The unconfined evolution form of mudstone is mainly distributed in some areas in the northwest and east of it;The evolution form of mudstone sealing unclosed is only distributed in the northeast and northwest parts of the country;The evolution form of fault unclosed is only distributed in the southern part;The evolution form of mudstone sealing fault unsealing is mainly distributed in the eastern region;The evolution form of unsealed closed fault is mainly distributed in the middle and south of the fault;The evolution form of mudstone sealing fault sealing is mainly distributed in the middle eastern region.(5)In Banqiao Beidagang area,the sealing evolution form distribution of the fault cap configuration of the lower Shahejie Formation controls the horizontal distribution of oil and gas in the lower Shahejie formation.Oil and gas are mainly distributed in the mudstone sealing mudstone not sealing,fault not sealing and mudstone sealing fault sealing evolution form distribution areas;The sealing formation period of fault cap configuration controls the amount of oil and gas distribution in the lower Shahejie formation.The initial formation period of mudstone sealing is the late deposition of the eastern second member,which is earlier than the hydrocarbon expulsion period of the source rock in the third Shahejie formation,which is conducive to the accumulation and preservation of oil and gas in the lower Shahejie Formation reservoir.The formation period of fault sealing is the late deposition of the upper Ming formation.Although it is later than the hydrocarbon expulsion period of the source rock of the third member of Shahejie formation,it can also seal a certain amount of oil and gas,which is more conducive to the accumulation and preservation of oil and gas in the lower member of Shahejie formation.The above research results and understanding have important reference value for guiding the oil and gas exploration of the lower Shahejie Formation in Banqiao Beidagang area. |
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