Study On Plugging And Migration Of Cross-linked Polymer Microspheres

Cross-linked polymer microsphere is a novel technology for deep flooding with a huge potential.After swelling,microspheres could attain a certain flexibility.Then at high displacement pressure,they have deformation and migrate into the next injectivity profile to develop a subsequent plugging.In this way,the whole profile control can be realized from the injection well to the oil well and accordingly the oil recovery will be enhanced.However,there are few studies of the relationship among the plugging migration and retention.In this paper,the Q microsphere which is synthesized by means of inverse suspension polymerization and the X microsphere which is synthesized by means of inverse emulsion polymerization are investigated.Their shape and size,swelling behavior is researched.In addition,the properties of plugging,migration and retention are evaluated.SEM,optical microscopy and laser diffraction particle size analysis technique reveal that powdered microspheres including Q microsphere and X microsphere are spherical and multiphase dispersed.As swelling time increases,the diameter of microsphere-dispersed system increases firstly and then decrease and then stabilize.As swelling temperature increases,its diameter increases.As crosslinking ratio(a ratio of crosslinking agent and monomer)increases,its diameter decreases.The micropore membrane filtration experimental results show that blocking effect of the microspheres is related to the size of microsphere and pore.Moreover if microsphere and membrane match well the plugging could be quite effective.As swelling time increases the plugging strengthens firstly and then weakens.As swelling temperature increases the blockage strengthens.As the crosslinking ratio increases the plugging of Q microspheres weakens.The sand-packed tube displacement experimental results demonstrate that as mass concentration increases X microspheres’ plugging for sand-packed tube strengthens.As permeability reduces the blockage strengthens.Judging from the effect of plugging and migration,the effect of profile control and displacement strengthens firstly and then weakens,as volume increases.There is a certain relationship between retention and plugging.If effective blockage is attained,effective retention could be attained.