CBE Colloquia - Advanced Flow Conformance via Mechanically Robust Hydrogel Particles in High-Salinity Porous Media

Conformance control in waterflooding operations is a crucial strategy for enhancing sweep efficiency and improving oil recovery in heterogeneous reservoirs. These reservoirs are often characterized by high salinity and elevated pressures, presenting significant challenges for traditional profile control agents. Preformed particle gels (PPGs) have emerged as effective agents to selectively block high-permeability zones, thereby redirecting injected water towards unswept, low-permeability regions rich in residual oil. However, conventional PPGs suffer mechanical degradation under strong shear forces during pore-scale transport. In this work, we develop and characterize a new class of functional hydrogel particles engineered for superior mechanical resilience and swelling behavior under saline conditions. The hydrogels exhibit a 3.4-fold improvement in tensile strength and a two-fold increase in equilibrium swelling ratio in brine solutions containing 200 g/L NaCl, compared to performance in deionized water. Using particle image velocimetry (PIV) in a micromodel, we directly visualize the real-time flow field and spatial distribution of the gels within a porous network. Core flooding experiments further validate the efficacy of the hydrogels, demonstrating a marked reduction in permeability and a significant increase in oil recovery factor. This study presents a robust strategy for flow control in challenging subsurface environments, offering promising implications for enhanced oil recovery (EOR) in high-salinity, high-temperature reservoirs.