Preparation of a micron-size silica-reinforced polymer microsphere and evaluation of its properties as a plugging agent

A kind of silica-reinforced polymer microspheres was proposed and prepared by inverse suspension polymerization, in which the nano-silica modified by 3-(methacrylyloxy) propyl trimethoxysilane (MPS) was used as reinforcing material. Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and dynamic light scattering (DLS) were utilized to analyze their structural properties. The effects of SiO2 on swelling capability, mechanical shear resistance, stability and viscoelastic property were studied. Plugging behavior was examined by sand pack model experiments. The results show that SiO2 can effectively adjust swelling behavior, and greatly improve mechanical shear resistance of polymer microspheres. Compared with conventional polyacrylamide microspheres, these silica-reinforced polymer microspheres displayed better dispersion stability and viscoelastic property. In addition, these microspheres exhibited an improved thermal stability, where the maximum degradation temperature was 11 °C higher than that of conventional ones. The plugging rate can be 83.87% and was promoted by 11.54% in sand pack model. This work can provide a viable candidate material for the deep conformance control in oilfields, and supply theoretical support for its application.