Study On The Starting Conditions Of Microscopic Residual Oil And The Mechanism Of Oil Film Deformation In Ultra-high Water Cut Period

With the development of oilfield entering the high water cut stage,the remaining oil distribution and occurrence state has happened great change,and the mining theory of low water cut stage is not suitable to the high water cut period.The reasonable division of remaining oil decided the complexity of research in high water cut stage.The force acting on the remaining oil is viscous force in the extra high water stage,which is displacement pressure in the initial stage of development.The force analysis of remaining oil determines the starting condition.Study on starting conditions and mechanism of oil film deformation has important significance of oilfield economic benefit,stable yield and yield increase.First,this paper expounds the necessity of the research,the purpose,significance of this research,tracking the current situation,main research contents,methods,principle and technical route and the innovations of this paper.This paper analysis of existing state of remaining oil and divided that into oil drops,oil film and sheet oil.Considering microcosmic oil force:capillary force,buoyancy,gravity,viscous force,additional resistance and friction resistance,established the equation of force according to fluid statics and dynamics.Secondly,this paper conduct sensitivity analysis based on the equation of force and find main force.Analyzed each layer of the oil film applying infinitesimal method and knowledge of statics and dynamics,and found the fracture initiation point of oil film in theory.We analyzed the migration of remaining oil in the channel and obtained the choice mechanism of the remaining oil according to the movement of the remaining oil under different forces.Finally,according to the remaining oil film deformation mechanism,the remaining oil channel selection theory and the nuclear magnetic resonance experiment of water flooding,this paper puts forward the definition of remaining oil start-up,and gives the starting conditions of remaining oil under various distribution conditions.