Study On The Reservoir Characteristics Of Chang 6 Oil-Bearing Formation,North District Of Binxian-Xunyi-Tongchuan,Shannxi Province

Through the systematic study of stratigraphic division,sedimentary facies characteristics and reservoir evaluation of the Chang 6 oil-bearing formation of the Triassic Yanchang Formation in the North Margin of Bin-Xun-Tong area,the southern Ordos Basin.Based on the identification of reservoir main controlling factors,The layers are comprehensively classified and evaluated.Studies indicate:1)The stratigraphic marker layer of the Chang 6 oil-bearing formation of the Triassic Yanchang Formation in the Bin-Xun-Tong North margin is obvious,and the stratigraphic distribution of each reservoir group is stable;the top structure shows the characteristics of “south high and low north,east high and low west”.The structure of the Nasal bulge of the Shilang Temple,the southern uplift,and the Zhengning depression was developed.2)There are two provenances in the southern and southwestern parts of the Bin-Xun-Tong North Margin.It is believed that the delta front sedimentary subfacies are developed in the area,and the sand deposits are deposited by turbidite.The main sedimentary microfacies have underwater distributary channels.,the underwater diversion bay and the underwater natural levee sedimentary microfacies;an underwater distributary channel is developed in the western and eastern parts of the area,the river runs through the whole area,and the distribution direction is NW-NE and NW.There are signs of river crossings in the middle of the area.3)The Chang 6 oil-bearing formation in the Bin-Xun-Tong North margin area is mostly lithic feldspar sandstone and feldspar lithic sandstone;the type of cement is mainly calcite and chlorite.The reservoirs are ultra-low-low-porosity and ultra-low-permeability reservoirs,and there are four types of pores: intergranular pores,dissolved pores,intercrystalline pores and micro-cracks.The type of throat is mainly micro-fine throat,and the pore type is mainly micro-fine pore.The main diagenesis activities include compaction,pressure dissolution and cementation,as well as dissolution and metasomatism.The diagenetic stage is in the middle stage of the diagenetic period A-B.Reservoir development is affected by sedimentary facies,diagenesis and tectonic activities.The reservoirs in the study area are classified into ?,?,? and ? four types of reservoirs.Type ? reservoirs are the best reservoirs,but only develop in the main part of the underwater distributary channel.Type ? and ? reservoirs develop on the flank or top of the underwater distributary channel.