Characteristics of composite microspheres for in-depth profile control in oilfields and the effects of polymerizable silica nanoparticles

Polymer/nano-SiO 2 composite microspheres (PNSCMs) were synthesized via inverse suspension polymerization with 3-methacryloxypropyltrimethoxysilane (MPS) modified SiO 2 as the reinforcing filler. The influences of these polymerizable nanoparticles on the swelling behavior, mechanical property, thermal stability, viscoelasticity and dispersion stability were examined in detail. Moreover, the plugging behaviors were investigated by sand pack tests. The results indicate that the introduction of these modified nanoparticles revealed a significant enhancement on the comprehensive properties of PNSCMs. By varying the content of MPS-modified SiO 2 , the environmental sensitivity of the microspheres’ swelling behavior was reduced. Besides, the mechanical property, thermal stability and viscoelasticity were greatly improved by increasing the SiO 2 loading. Compared with SiO 2 -free ones, PNSCMs exhibited better dispersion stability and plugging performance, and the maximum plugging rate reached 93.64%, which was increased by 14.69%. These PNSCMs studied can realize in-depth profile control in reservoirs and have great application prospects in the further enhanced oil recovery research.