Development and Characterization of CO₂–Responsive Intelligent Polymer Sealant

Abstract

In this study, we present an innovative intelligent polymer sealant designed to mitigate CO 2 leakage during underground geological storage (CCUS). This sealant is formulated by cross-linking CO 2 -responsive polymers, specifically acrylamide (AM) and N-[3-(dimethylamino) propyl] methacrylamide (DMAPMA), with polyethylenimine (PEI) serving as the cross-linking agent. The polymer sealant’s characteristics were systematically investigated, varying the CO 2 -responsive polymer content (1.5 wt %) and PEI content (0.1–0.6 wt %). A comprehensive analysis encompassing the rheological properties, thermal behavior, conductivity, and microstructures was conducted. Experimental results indicate that the polymer sealant exhibits excellent injectability, rapid response kinetics, thermal stability, and robust mechanical strength. Upon encountering CO 2 , the polymer system undergoes a transition from sol to gel state, forming a surface-smooth, uniformly porous three-dimensional (3D) network skeleton structure. Remarkably, the gel’s modulus remains relatively unaffected by the shear frequency. Core fluid displacement experiments demonstrated a substantial sealing efficiency of 73.6% for CO 2 and an impressive subsequent injection water sealing rate of 96.2%, underscoring its superior sealing and migration performance. In conclusion, the proposed CO 2 -responsive gel sealant exhibits an exceptional potential for successful utilization in CCUS operations. This advancement introduces a novel avenue to enhance the effectiveness of CO 2 -responsive gel sealants, thereby contributing to the advancement of CO 2 leakage mitigation strategies in geological storage scenarios.

Preparation of CO2-Responsive Biobased Ternary Composite Microgel and Its Application in Reservoir Gas Channeling Plugging

“…As the only alkaline polysaccharide in nature, chitosan (CS) itself contains a large number of primary amine (−NH 2 ) groups and is a potential CO 2 -responsive natural polymer. − Therefore, a CO 2 -responsive microgel material was designed and prepared in this paper by using biomolecular CS as the main raw material and functional groups with CO 2 response as a breakthrough. − This kind of microgel had excellent CO 2 response and showed obvious viscoelasticity after CO 2 response. Therefore, this CO 2 -responsive microgel can be used as a CO 2 gas channeling plugging agent for application in the reservoir, so as to effectively improve the sweep rate and sweep volume of CO 2 gas drive in the reservoir, improve the recovery factor of the reservoir, and realize the effective utilization of CO 2 while creating higher economic value. − On the other hand, injecting N 2 into this CO 2 -responsive microgel can make it change back to the liquid state, which is conducive to the backflow of gas channeling plugging agent and avoid formation pollution.…”