Volumetric Swelling Behavior of <scp>PAAm</scp> / <scp>PVA IPN</scp> ‐Based Particulate Agents and Plugging Control Design

ABSTRACT This study systematically analyzes the volumetric swelling behavior and plugging control mechanism of interpenetrating polymer network (IPN)‐based swelling particles. This addresses the issue of existing evaluations relying primarily on swelling multiple based on mass, which fails to meet the field requirements for matching particle size with pore‐throat plugging of reservoirs. IPN particles were prepared using stepwise and synchronous methods. Their microstructures, swelling rates, volumetric swelling multiples, and the effects of temperature and salinity on swelling behavior were tested and analyzed. Furthermore, a plugging control particle size calculation model was established. Due to the influence of network compactness, the volumetric swelling multiples of IPN particles increased by 8.1%~17.0% or decreased by 13.0%~27.9% compared to conventional PAAm‐MBA. The increase of temperature promoted amide group hydrolysis and chain relaxation, enhancing volumetric swelling multiples by 55%, while salinity suppressed swelling by shielding hydrophilic groups, reducing it by 58%. The swelling process was divided into three stages: capillary water absorption, chain relaxation, and osmotic pressure control, conforming to non‐Fickian diffusion. The “permeability–pore‐throat size–migration time–volumetric swelling multiple–initial particle size” associated control calculation model enables precise design for deep‐profile particle plugging. The research results provide a theoretical basis for the design and field application of swelling particles.