Research On The Matching Relation Between The Diameter Of Elastical Particle And Permeability Of The Formation

The compatibility between particle and pores has great influence on the injection property and plugging effect of plugging agent.The matching relation between rigid particle size and permeability has been well learned so far,however,few attempts about the matching relation between elastical particle size and permeability has been conducted.In this paper,the matching relation between the diameter of elastical particle and permeability of the formation and the transport mechanism of elastical particle in porous media was studied by using the XJ elastical particle.The matching relation between the diameter of elastical particle and permeability of the formation was investigated by using experimental and mathematical modeling method.The empirical function relation among the starting pressure gradient,the particle concentration,and the particle diameter-throat diameter ration,also the change of matching factor with particle concentration and injection rate,and the change of deposition coefficient with injection concentration,injection rate and particle size are regressed according to the pressure data(pressure fluctuation)and porosity variation.Then the mathematical model was bulited by combining the mass conservation equation and the above three empirical function relations.The calculated outcome of injection pressure and porosity change by using the mathematical model were matched well with the experimental data,indicating the rationality of the mass conservation equation and the above three empirical function relations.According to the three empirical function relations,the particle diameter-throat diameter ration in which the particle can be injected into formation and exert good plugging effect lies in the range of 0.193-1.28(it is related to particle concentration and injection rate),and this range is larger than that of rigid particles(1/7-1/3,0.143-0.33).The three migration and plugging mechanisms of elastical particle in porous were summaried according to the pressure fluctuation and variation data: particle deposition,particle deformation and mechanical plugging.Elastical particle can enter the pore and throat more easily through elastical deformation and it can deform and push on porous media,thus it can be used for deep profile control.The results show that the influencing factor of matching factor includes particle concentration,injection rate,injection pressure and particle type(elasticity).And their influencing mechanisms are different with each other.In the matching range,the elastical particle can extrude,deform and pass the throat and thus can result in pressure fluctuation,and the pressure fluctuating follows that it first slowly increase and then abruptly decrease.The amplitude of pressure fluctuation increase with the particle concentration-throat diameter ratio and injection rate.The elastical particle can enter the throats more easily compared with rigid particles due to its elastical deformation,thus it can deform and push on in porous media with increasing pressure and can be used for deep profile control.The injection property and plugging property of elastical particle was compared with that of rigid paeticle.Due to different matching property and migration property in porous media,elastical particle has better injection property,plugging effect and washing resistance.