Laboratory studies of the feasibility for microencapsulated polymer flooding

Conventional polymer flooding faces challenges in terms of injection difficulty and shear degradation when applied in medium- and low-permeability reservoirs. Microencapsulated polymer flooding, as a promising method for enhancing polymer flooding, involves encapsulating the polymer within microcapsules to resist shear and improve the injectivity. In this study, we conducted a series of experiments to explore the fundamental properties of thermo-sensitive microencapsulated polymer, including dispersion stability, injection, shear resistance and viscosity enhancement. The experimental results show that the microencapsulated polymer is a spherical particle with core-shell structure, which is easy to disperse and has good stability. The microcapsule size is from 0.1 μm to 1 μm, making it to be better injected into formations. The microcapsule shell has excellent shear resistance, that after undergoing high-speed mechanical shearing, the trigger viscosity of the microencapsulated polymer can still reach 97.4% of the initial viscosity. Thickening experiments show that the microencapsulated polymer has a delayed thickening property in the range of 50-90℃, and it can be released inside the core, resulting in higher flow resistance. This study provides a more detailed evaluation of the application potential of microencapsulated polymer, which proves that the microencapsulated polymer flooding is a feasible and powerful technology for EOR.