Experimental and molecular simulation study of in-situ self-growing nano-liquid crystal for smart water management in natural gas reservoirs

Natural gas reservoir development faces significant challenges from water invasion due to reservoir heterogeneity. Thus, effectively controlling water invasion while simultaneously facilitating gas production presents a significant historical mission and a vital research hotspot. A key research gap exists in developing water control agents for natural gas reservoirs that combine smart selective plugging and efficient profile control, with limited understanding of GO-based nanocomposites mechanisms and functionalization. Thus, this study pioneers a novel method for designing graphene oxide (GO)-based nano-liquid crystal sheets (GOLC) to address this issue. The design was inspired by the in-situ scale growth due to the association with inorganic salt ions in the formation water and hydrocarbon dissociation of polyethylene glycol (PEG) hybrid GO nanocomposite. Experimental and molecular simulation characterizations were employed to elucidate and investigate the intelligent water control and gas evacuation mechanism of GOLC. GOLC exhibits excellent dispersion in polar solvents. The in-situ growth of GOLC, driven by electrostatic interactions between PEG and metal cations (Ca²⁺ > Mg²⁺ > Na⁺), enlarges GOLC sheets from 50 nm to 3500 nm, achieving an 84.81 % plugging rate in porous media. Interestingly, these self-growing GOLC structures dissociate upon contact with methane (CH₄), showcasing effective water blocking and gas drainage characteristics, which results in a 12.9 % increase in recovery rate. This research will provide an innovative perspective for the synthesis and application of newly generated nanomaterials following a de novo design to intelligently control water in natural gas reservoirs.