Reservoir Characteristics Of The Lower Submember Of The Second Member Of Shahejie Formation In The South Area Of Pucheng Oilfield

Most oilfields in eastern China have been the middle and late stages of development,the exploration and development of remaining oil are becoming increasingly difficult,with the increasing degree of reservoir exploitation.Thus,the study of reservoir characteristics is greatly significant.In reservoir research,whether the most basic core data in the early stage or then the more elaborate heterogeneity,they are to guide the evaluation of the final reservoir and the prediction of residual oil distribution.Therefore,from qualitative to quantitative and from macroscopic to microscopic research,analyzed reservoir characteristics and classify reservoirs,which is of great significance to the prediction of remaining oil distribution and the improvement of oil recovery in the later stage.This paper is mainly based on the core date,analysis and test data,logging data of the lower submember reservoir of the second member of Shahejie formation in south area Pucheng oilfield,and combined with the regional geological background,studied the types of sedimentary facies,summarized the spatial distribution of facies belts,and analyzed the physical properties and heterogeneity of reservoirs.Finally,classified and evaluated the reservoirs in the study area,which laid a theoretical foundation for later reservoir development.The main work in this paper is as follows:According to logging data and core,the correlation skeleton profiles of connecting wells with small layers are established,and the small layers are re-divided and compared in the whole area by using cycle correlation controlled by marker layers.Guided by the principles of petrology and sedimentology,analyze the sedimentary structure and grain size characteristics of strata,determine the distribution of sedimentary microfacies,carry out the analysis of single-well facies and connecting-well facies,compile the plane distribution maps of sedimentary microfacies of each sublayer,and clarify the plane distribution law of sedimentary microfacies of each sublayer in the study interval.According to core well data,casting thin section,core analysis data,under the guidance of reservoir geology,sedimentary petrology and physical characters of rock,the petrological characteristics,pore and throat types and reservoir physical properties are analyzed.Based on the results of sedimentary microfacies and physical property analysis,the reservoir heterogeneity is studied,including intra-layer heterogeneity,interlayer heterogeneity and plane heterogeneity.In addition,analyze the plane distribution of porosity and permeability.Finally,based on the analysis of reservoir sedimentary microfacies,petrological characteristics,pore structure and physical properties,selected evaluation parameters and establish reservoir classification and evaluation criteria in the study area.The study area is mainly divided into three types of reservoirs,of which type ? reservoir has the best reservoir performance and mainly are developed underwater distributary channel microfacies.