A study on the stability of amphiphilic cellulosic materials and the CO2-responsiveness of their interpenetrating network derivative with polyacrylamide

Ensuring the permanent containment of CO 2 in geological formations necessitates robust methods for conformance control. Lately, attention is being shifted towards the use of cheap and environmentally-friendly composite materials, wherein the stability and viscosifying power in situ remains a challenge. In this study, a family of interpenetrating network composites was formulated by crosslinking polyacrylamide in a hydrophobically-modified cellulose sulphate solution to form a gel. The stability and mechanical properties of the gel were investigated using turbidimetry and molecular dynamics simulation. The hydrophobically-modified cellulose sulphates attained reasonable stability in saline conditions typical of the subsurface environment. They had moderate compatibility with crosslinked polyacrylamide, which was further improved by guanidine hydrochloride, leading to a more cohesive interpenetrating network at a representative reservoir temperature. In the same vein, the tertiary amine salt also improved the quality of the gel after exposure to CO 2 , where they demonstrated enhanced thickening and elasticity with CO 2 in an ionic environment. With this stability in the presence of CO 2 and improved mechanical properties in situ harsh reservoir conditions, these novel interpenetrating network gels stand as a promising material for increasing CO 2 storage security in subsurface formations.