Numerical Simulation Of The Seepage Mechanics Of Preformed Particle Gel In Reservoir

Preformed particle gel can be suspended in the water after swelling.During the migration,they will be p lugged when they meet the thin pore.But they will deform through the throat under large preassure.So that they can be migrated into deep formation and achive the effect of deep profile-control.Currently,the mathematical models describing the migration of PPG in the formation are almost built on the base of classical filtration model.But they don't consider the microscopic features such as the pore size and distribution density.Therefore they can not correctly study the compatibility of pore size and p article size.Size exclusion starts from the pore distribution and assume that the particles which are smaller than the pore size will pass through the throat but the particls which are larger than the pore size will be plugged.Therefore it can correctly describe the mechanism of the formation physical property change.But the exist size exclusion model is built to describe the single phase flow.The process of PPG particle displacement is two-phase flow and PPG particle can deforme through the pore throat.Therefore the size exclusion theory can't be directly applied to built the numerical simulation model of PPG particle deep profile control.In this thesis,work starts with the pore distribution and assume that the particles which are smaller than the pore size will pass through the throat but they can be adsorbed in the certain probability.And meanwhile the particls which are larger than the pore size will be captured by the pore.After that the features of oil-water two-phase flow are be considered,the size exclusion theory is extended to discrbe two-phase flow.The single sized PPG particle mass conservation is built and the method which is used to calculate the new distribution density after the plugging in the thin pore and the adsorption in thick pore.Finally,the complete mathematic model is given.Developed model is validated and affection of several parameters to profile control effection is studied.Reliability of the developed model is confirmed by matching the results of indoor double tube experiments including separate system ratio and injection preassure.Core displacement model and geological model are set up.And numerical simulation is carried on.Analysised parameters affecting profile control effection include comparing two cases where if the reboot mechnasim is considered,injection rate,injection PV numbers,injection concerntion,the ratio of paticle diameter and pore diameter and critical pressure.Then analysising and summarying the transport mechnasim of the preformed particle gel in the porous media:the preformed particle gel can be used to carry on deep profile control precisely because they can pass through the pore throat by deformation;the greater the injection concerntion or injection PV numbers,the wider the scope of plugging.But if the injection concerntion and injection PV numbers are excessive,it will casue harm to the strata.So there are optimal injection concerntion and injection PV numbers;the higer the injection rate,the higer the PPG particle transport velovity,but the blocking effect will have a certain degree of decline.So there are optimal injection rate;for the certain strata,the smaller the particle,the higer the PPG particle transport velovity,but the blocking effect will have a certain degree of decline.So there are optimal size of particles;for the certain size of particles and porous media,the smaller the critical pressure,the higer the PPG particle transport velovity,but the blocking effect will have a certain degree of decline.So there are optimal critical pressure.