The Remaining Oil Microcosmic Distribution Of Polymer Flooding And Molecular Dynamic Simulation

In the paper, the relation between polymer solution and oil film is described by molecular dynamic theory. The relation between polymer solution and oil can be devided into two types,one is the pushing force and the other is the shearing stress.According to force annlysing, it is concluded that interface friction is the mostly factors that affecting EOR. Because the polymer solution is of viscoelastic,it can lead to pulse force that change the static oil to moving oil .when the force arrive to the lower level, it cann't chang the separated oil to static oil.In water flooding, the colliding force of the water molecule may is bigger than polymer's, and then the water flooding efficiency is over than the polymer's.The interface film is measured by means of the CIR-100 rheometer. The results show: the viscosity and elastic moduli between polymer solution and oil film increase with the increase of the thickness of the polymer solution.The mainly reason is that the increase of polymer molecule improve the chance of the collide and friction among molecules.In different brine salinities, the interface viscosity change differently with the polymer thickness.Study the influence factors of distribution of the remaining oil in polymer flooding reservoir and take fluorescence analysis on the different rock. Study the influence of inaccessible pore volums to polymer flooding and surface friction function. The result shows that: Polymer solution with visco-elastic characteristic increase micoscopic oil displacement efficiency and expand sweep factors;The visco-elastic characteristic improve friction between oil film and polymer solution;Different flooded degree leads to different character remaining oil; The remaining oil distribution is influence to inaccessible pore volumes.By solving the differential equation of the Newton No.2 law, the movement track and movement rate can be gained.Using the statistical physics, some macro-parameter can be getted.Study on micro-pore liquid shows: the liquid viscosity is over than it's normal viscosity.Liquid Viscosity reduce with the increase of film thickness.The mechanism between the AFM probe and the rock surface is very complex.The mechanical model for AFM tip sliding on surface of sample was set up.It is useful to deeply observation by AFM. Key words: polymer flooding, remaining oil distribution, molecular dynamics simulation,viscosity, atomic force microscopy...