Preparation and profile control evaluation of core‐shell structure and surface‐hydrophobic modified polyacrylamide microsphere

Abstract Polyacrylamide (PAM) microsphere has been widely used in the field of profile control to reduce water cut in heterogeneous reservoirs. However, its mechanical strength and plugging ability are still needed to be improved. In this paper, a core‐shell structure and surface‐hydrophobic polyacrylamide M‐P(AM‐PEP) microsphere was prepared by using acrylamide (AM), block polyether macro monomer (PEP) and modified SiO 2 with double bond on the surface as monomers through dispersion polymerization. After the optimization of synthesis conditions, the results of SEM and TEM confirmed that M‐P(AM‐PEP) microsphere had the nano‐scale spherical shape and the inorganic core/polymer shell structure, while the contact angle test results showed that M‐P(AM‐PEP) microsphere had the surface‐hydrophobicity. Swelling experiments presented that the size of M‐P(AM‐PEP) microsphere can be increased by 6 times and had obvious self‐gathering behavior. The inorganic core and self‐gathering behavior are helpful for improving mechanical strength and plugging ability of PAM microsphere, respectively. Profile control and oil recovery improvement experiment showed that injecting 0.1 PV M‐P(AM‐PEP) microsphere can decrease the water cut and increase the oil recovery of 17.95%. This new microsphere could be an efficient technology for the profile control in the heterogeneous reservoir.