Study On Sedimentary And Reservoir Characteristics Of The Lower Es₂ In YongBa Oilfield

The research area of this dissertation is located in the middle of the Dongying sag.The research area is divided into many blocks because of the ancient earthquake and fault.The research area of this paper includes the old area of XinLicun in the North area and the new area of Yongba in the South.The study area runs through the whole sand section,but it mainly study the the bottom of this sand section?Es₂5,Es₂6,Es₂7,Es₂8?.The research content of this dissertation includes sedimentary and reservoir.In the research of this paper,we mainly refer to the core wells:Yongba XJ1 well and Yong8-7 well;refer to YongCe111 well and Yong 104 well because it has the complete recorded and logging data.In addition,this paper also refer to the core wells of Yong101,Yong102,Yong20-1 and Yong104 because it is located in the old area of XinLicun oil field in the South.Through fine stratigraphic comparison,small layers of sand,recorded data,logging data,core data,planar sedimentary microfacies and profile sedimentary microfacies.We can conclude that the source of Yongba area in Dongying sag is mainly from the northern Qingtuozi and Chenjiazhuang bulge.In Es₂1-Es₂4 section of the study area,it has relatively thin formation and less sand body,In Es₂5-Es₂7 section,the formation is thick,the source is abundant,the sand body is very developed,Hence,it can be a good reservoir.In Es₂8-Es₂9 section,the layer is thick,but it is almost undeveloped.So,we can conclude that,in Es₂1-Es₂2,it is terrestrial river facies,the main sedimentary microimages are swamps and lakes in this layer.In Es₂3-Es₂4 section,it mainly consists of delta plain facies,and it is the water diversion channels.In Es₂5-Es₂7 section,it is the delta front subfacies,it mainly develops underwater distributary channel sedimentary microfacies,which is a good reservoir.Through the analysis of rock casting sheet,scanning electron microscope,X-Ray,clay mineral assay,grain size curve analysis,capillary pressure curve analysis,separation,roundness,etc.we can conclude that The rock type in the study area is feldspar quartz sandstone,with weak diagenesis and compaction and 2.5%clay content.The clay minerals are mainly Gaolingshi and Mengtuoshi,The size is rough with average 0.18 mm.The reservoir porosity ranged from 27.7%to 33.1%,with an average of 31.7%of reservoir porosity and an average 1.039?m² of permeability,with 5.0 of permeability difference.The inrush coefficient of each layer averaged 3.26,the variation coefficient averaged 0.89and the inhomogeneous degree was stronger than that of the interlayer.