Enhancing P(AM-co-AA) hydrogel performance: Dual crosslinking effects on structural strength, thermal stability, swelling capacity, and rheological behavior for effective sand production control in oil reservoirs

The efficiency of mechanical methods in controlling water production and fine migration in reservoirs has been limited, prompting researchers to focus on developing more resilient chemical methods. However, the challenge lies in the limited resistance and stability of these chemical methods in harsh reservoir conditions. To address this challenge, a study evaluated a dual crosslinker polyethyleneimine compound as a double crosslink in hydrogel composite structures. Using FTIR techniques, the study examined the structure of hydrogel compounds with single and double crosslinkers. Microscopic imaging, including SEM and ESEM analyses, provided insights into sample morphology. Equilibrium swelling and rheological tests assessed the hydrogels' three-dimensional structure and solvent retention capacity, while TGA determined sample stability. The study confirmed chemical bond formation between double crosslinkers via FTIR analysis. SEM and ESEM images displayed a porous, homogeneous, three-dimensional structure. The increase in pore size in the swollen state without tearing highlighted the hydrogel's elastic and self-healing properties. TGA revealed reduced weight loss with double crosslinking at 120 °C. Strain sweep and frequency sweep tests demonstrated enhancements in critical strain and frequency with the dual crosslinker, supporting the sample's viscoelastic behavior. The hydrogel with a single crosslink maintained linear viscoelastic behavior up to 85 °C, while the dual crosslinked sample retained it up to 200 °C, suitable for high-temperature conditions. Swelling tests confirmed the sample's ability to absorb 2000% of water under reservoir conditions. Sandpack compressive strength testing indicated a fivefold increase in strength with the dual crosslinked hydrogel composite, effectively preventing fine migration.