The Research Of Hydrocarbon Accumulation Conditions Of Buried Hills In Shaleitian Uplift

The Shaleitian Uplift has excellent prospects for exploration in the Bohai Bay Sea,but the basic research work on its oil and gas geology has not been comprehensive enough so far.Therefore,this paper takes the Shaleitian Uplift as the main research object,and based on the petroleum geology,structural geology,oil and gas organic geochemistry and other discipline theories,based on the previous research results,make full use of geological and geochemical data.The hydrocarbon accumulation conditions,reservoir conditions and caprock sealing characteristics of buried hills are analyzed.Combined with the accumulation anatomy of buried hill reservoirs,the main controlling factors and accumulation patterns of buried hill reservoirs are summarized.The comprehensive study shows that:?1?The Shaleitian Uplift mainly develops3 sets of source rocks in the third sections of dongying,the first section of shahejie to the second section of shahejie,and the third section of the shahejie.The third section of shahejie is the main source rock in the study area,with high organic matter abundance,organic matter types of II₁ and II₂,and high maturity.The oil sources are mainly mixed sources,mainly supplying hydrocarbons for the third section of the shahejie,and some of them are mixed with the first section of shahejiehe and third section of dongying.?2?The buried hills in the Shaleitian bulge mainly develop three sets of reservoirs:Mesozoic clastic rocks,Paleozoic carbonate rocks,and Archean metamorphic rocks.Due to the influence of factors such as lithology,tectonic movement and buried hill depth,Mesozoic clastic rock reservoirs can be classified into Class I high-quality reservoirs according to the causes of weathered fracture zone at the top,seepage zone under weathered crust,reservoir physical properties The carbonate reservoirs in the Paleozoic are Class I high-quality reservoirs,and the metamorphic rock reservoirs in the Paleozoic are good Class II reservoirs.?3?The buried hills in Shaleitian bulge have regional caprocks in the whole area of Dongying Formation and regional caprocks in the eastern area of Shahejie Formation.Among them,the mudstones in the eastern and northwestern sections of Lower East2nd to East 3 have double sealing effects of physical properties and overpressure;The distribution of mudstone in the third member of Shahejie Formation is limited to the eastern and northwestern sections of the bulge,and it has the double sealing effect of physical properties and overpressure;the main development is fault-unconformity transmission system and fault-unconformity-sandbody type transmission system.System;the oil supply mode is in-source and near-source oil supply;the accumulation mode is single-unit source transport type.?4?The main controlling factors for the formation of buried hills in the Shaleitian bulge are high-quality reservoirs,dominant transmission systems,and near-oil sources and late filling of oil and gas;the study areas are mainly distributed in class I and class II exploration areas.class I favorable exploration zone CFD18-1?CFD18-2 buried hill zone in the southeast of Shaleitian,class II sub-favorable exploration zone is the east-west buried zone of CFD6-4S?CFD12-6?BZ8-4 located in the northeast of Shaleitian Uplift and northwestern of Shaleitian,respectively CFD1-6?CFD2-1 buried hill zone.