A comprehensive investigation of polymer microspheres (PMs) migration in porous media: EOR implication

A type of polymer microspheres (PMs) with superior dispersity, swelling, elasticity, and saline and temperature resistance was prepared in this work through inverse emulsion polymerization. It was observed that these PMs experienced elastic deformation and obstructed micro-pores by means of complete, single and bridge plugging, and thus causing additional flow resistance. The migration modes of the PMs in porous media could be defined as smooth pass, elastic plugging-remigration incorporating low-efficiency and high-efficiency plugging, and complete plugging, on the basis of matching coefficients between the PMs and pore geometry. The plugging capability of the PMs was largely dependent on the matching coefficients. Interestingly, it was found that if appropriate matching coefficients was obtained, the PMs with higher elastic modulus showed an enhanced plugging capability even with smaller particle size. In addition, the results of adsorption and desorption behaviors of the PMs implied that the adsorbed PMs partially detached as a result of caused flow fluctuation and decline/disappearance of secondary adsorption potential well. It is believed that the proposed PMs could be a viable, robust and promising candidate for conformance control and oil recovery improvement.