Study On The Sedimentary Characteristics And Favorable Reservoir Distribution Of Yan 9 Formation In Wangquze, Jingbian Oilfield

Ordos Basin which is rich in oil and gas resources is the second largest petroliferous basin in China.Jingbian WangQuze area which is located in the central of the Shanbei slope is still in the progressive exploration and development stage.Analyzed from the proven reservoirs are mainly distributed in Yan'an formation of Yan 9 oil-bearing strata.Based on the use of the core,well logging,logging and analysis test data,this paper makes a detailed stratigraphic division and correlation of the Yan 9 oil-bearing formation in the study area,and analysis of sedimentary microfacies and sand body distribution law,studies the reservoir characteristics of this area.Combining the research results of sedimentary and reservoir,the distribution of favorable reservoir is determined.In this study,Yan 9 reservoir is divided into 3 small layers,according to the principles of the marker layer,sedimentary cycle and stratigraphic thickness.The characteristics of the top structure are as follows: the strata are gentle in the study area,and the structure of the nose is tilted to the west.The sedimentary facies in the study area are meandering river deposits,which is divided into the river deposited,beach,natural levee,crevasse splay,floodplain 5 sedimentary microfacies in the study area.There are 2 NW-SE trending meandering river.The distribution of sand bodies is controlled by sedimentary microfacies distributing in the NW-SE direction.The main rock types of the Yan 9 Formation in the area are mainly lithic feldspathic sandstone.The reservoir spaces mainly develop intergranular pores,secondary dissolution pore and a small amount of micro cracks.Diagenesis includes compaction,cementation and dissolution.There are four types of pore throat combination are common,large pore type,pore throat type,pore fine throat and pore fine throat type.Comprehensive evaluation of reservoir can be divided into 3 types: medium permeability reservoir,low permeability reservoir and extra low permeability reservoir.The distribution of favorable reservoir is determined by the research results of sedimentation and reservoir.The favorable reservoir is mainly distributed in the sand bar with large thickness and good permeability.