The Microscopic Remaining Oil Formation Mechanism And Distribution Characteristics Of Donghe Sandstone In Hadeson Oilfield

This thesis focuses on the microscopic remaining oil of Donghe sandstones in Hadson Oilfield,in order to characterize the microheterogeneity of reservoirs,research the formation mechanism and distribution of microscopic remaining oil and propose effective measures of excavating the microscopic remaining oil which lays a foundation for tertiary oil recovery.By means of core analysis data this thesis describes the pore structure both qualitatively and quantitatively,divides the types of pore structure and summarizes the levels of microheterogeneity.This thesis sets up the levels of micro-pore structure: overall distribution characteristics of internal pores?pore throat structure differences?partial pore throat combinations and internal pore heterogeneity.This thesis proposes that the blocking and emigration of clay minerals lead to the physical changes of reservoirs;the matching ability between clay minerals and core throat controls the direction of physical changes before and after water flood.According to the data of undisturbed and water-flooded formations this thesis analyzes the varying mechanism and law of microheterogeneity before and after the water flood,This thesis definite the formation mechanism of microscopic remaining oil controlled by the relative size of power and resistance,displacing velocity and removal velocity,which includes the internal cross flow of core level,micro-circle flow,fingering advance and side surpass caused by pore throat combinations and the trapping,penetrating,stripping and locking in a single pore.Then chooses typical cores to perform CT?NMR?micro etching displacement models experiments,and summarizes the distribution mode of microscopic remaining oil,which includes overall distribution characteristics,the enrichment difference caused by core throat structures,the distribution heterogeneity caused by partial pore throat combinations and the distribution mode in a single pore.Besides,this thesis definites the potential types of remaining oil and puts forward targeted tertiary recovery technique.