Prediction Of Residual Oil Distribution Of Heavy Oil In Block Dongtan 36 Of Fuyu Oilfield

The production of Fuyu Oilfield in Jilin Province shows a decreasing trend year by year.The production of single well is low,the recovery degree is relatively low,and the water cut is high.At the same time,the surface degassed crude oil in Block Dongtan 36 of Fuyu Oilfield has the characteristics of high viscosity,high solidification point and high wax content,which belongs to common heavy oil.The recovery degree is lower and the basic geological research is less.With the change of oilfield development mode and long-term development under saturated pressure,crude oil viscosity gradually shows an upward trend.Based on the present situation of oil field,it is necessary to explore the distribution law of heavy oil remaining oil based on reservoir geology research and the technology of enhancing oil recovery mainly by changing development mode.On the basis of previous research results,this paper takes structural geology,sedimentology,development geology and petroleum geology as theoretical basis,synthetically uses data of geology,logging and core analysis,and proceeds with the actual situation of the study area,and carries out stratigraphic division and correlation,sedimentary microfacies characterization,secondary interpretation of logging,fine reservoir geological modeling,reserves recalculation and reservoir numerical simulation.In this paper,the method of "cyclic correlation,hierarchical control" is used to compare reservoirs.According to the variation law of gamma curve and resistivity curve,Fuyu reservoir is divided into four sand groups and 13 sub-layers according to the sedimentary cycle from large to small.Starting from the regional sedimentary background,through core observation and analysis of laboratory data,it is determined that Fuyu reservoir is a delta deposit under the mode of weak oxidation-weak reduction,in which the first and fourth sand formations are mainly delta front subfacies deposits,and the second and third sand formations are mainly delta plain subfacies deposits.Then,based on core data of coring wells,typical log curves of various microfacies of delta front subfacies and delta plain subfacies are completed,and the microfacies types and plane distribution rules of sand bodies are determined by logging facies analysis.The spatial distribution of each sedimentary unit is characterized by the combination of profile and plane.Through secondary interpretation of logging data,shale content model,porosity model,permeability model and saturation model are established to provide accurate logging data for geological modeling.Then,using PETREL modeling software,a stochastic modeling method was used to establish a fine three-dimensionalgeological model in the study area,and numerical simulation was carried out.The results show that the remaining oil mainly develops in 3,5,6,7,8,11,13 layers,and concentrates in areas where injection and production are not perfect or well pattern is uncontrolled.At the same time,some suggestions are put forward on the mining plan with the injection of viscosity reducer as the main method.