High-Temperature Stable Dispersed Particle Gel for Enhanced Profile Control in Carbon Capture, Utilization, and Storage (CCUS) Applications

CO₂-responsive gels, which swell upon contact with CO₂, are widely used for profile control to plug high-permeability gas flow channels in carbon capture, utilization, and storage (CCUS) applications in oil reservoirs. However, the use of these gels in high-temperature CCUS applications is limited due to their reversible swelling behavior at elevated temperatures. In this study, a novel dispersed particle gel (DPG) suspension is developed for high-temperature profile control in CCUS applications. First, we synthesize a double-network hydrogel consisting of a crosslinked polyacrylamide (PAAm) network and a crosslinked sodium alginate (SA) network. The hydrogel is then sheared in water to form a pre-prepared DPG suspension. To enhance its performance, the gel particles are modified by introducing potassium methylsilanetriolate (PMS) upon CO₂ exposure. Comparing the particle size distributions of the modified and pre-prepared DPG suspension reveals a significant swelling of gel particles, over twice their original size. Moreover, subjecting the new DPG suspension to a 100 °C environment for 24 h demonstrates that its gel particle sizes do not decrease, confirming irreversible swelling, which is a significant advantage over the traditional CO₂-responsive gels. Thermogravimetric analysis further indicates improved thermal stability compared to the pre-prepared DPG particles. Core flooding experiments show that the new DPG suspension achieves a high plugging efficiency of 95.3% in plugging an ultra-high permeability sandpack, whereas the pre-prepared DPG suspension achieves only 82.8%. With its high swelling ratio, irreversible swelling at high temperatures, enhanced thermal stability, and superior plugging performance, the newly developed DPG suspension in this work presents a highly promising solution for profile control in high-temperature CCUS applications.