The Study Of Thin And Poor Oil Layer Evaluation In Es3 Member Of Guan187 Area Of Huanghua Depression

The main oil-bearing series in Guan187 area of Huanghua Depression are Es1 and Es33 oil groups.After long-term production,the block has high water content and low liquid production in recent years,the main oil reservoirs have entered the stage of high water cut with high recovery degree,and most oil Wells have been shut down at low energy.It is urgent to find non-main reservoirs with certain development potential to supplement oil and gas supply.There are a large number of dry layer,low yield oil layer and poor oil layer such as potential oil layer for the development in Es33 oil groups of Study area.Therefore,this thesis takes thin and poor oil layer of Es33 oil group in Guan187 area of Huanghua depression as the research object,establishes the thin and poor oil layer identification methods and standard,clears the reservoir characteristics,carry out the study on formation mechanism of thin and poor oil layer from the aspects of sedimentation,diagenesis and tectonism,predicts plane distribution of reservoir,finally completes comprehensive evaluation of thin and poor oil layer,to provide guidance for the future oilfield development.The thickness of Es33 oil group in Guan187 area is between 20 m to 80 m,which divided into 2 single layers and 7 single sand bodies based on the characteristics of mud interlayer.The southern strata are well developed,while the lower strata in the north are partially missing.The type of sedimentary facies in the study area is the braided river delta front facies,with the provenance direction from southwest.The underwater distributary channel microfacies with obvious characteristics is mainly developed with well vertical inheritance.Based on the division of single sand body,definite the lower limit standard of thin and poor oil layer in the study area,as follows: fine sandstone,Por>9.6%,Perm>0.1m D,AC>268.2μs/m,RT> 4.03Ω·m,and the reservoir thickness is greater than 0.9m.The physical properties of thin and poor oil layers in the study area are generally poor,and the reservoirs can be divided into three types based on the genetic mechanism and reservoir characteristics.During the development of thin and poor oil layers,sedimentation determines the original physical properties of the reservoir.Class I reservoir is mainly developed in underwater distributary channel microfacies.In diagenesis,feldspar dissolution pores are formed by dissolution,which improves the physical properties of thin and poor oil layers.The destruction of reservoir physical properties by strong cementation is the main reason for the formation of class Ⅲ reservoir.Among them,class Ⅰ and Ⅱ reservoirs have good physical properties and have certain development potential,which can be used as the main target areas for the next development of the oilfield.