Containment strategy for subsurface H2 storage based on time-dependent soft solids.

We propose an innovative containment strategy based on time-dependent soft solids, namely 2 wt% Laponite suspensions, to reinforce natural subsurface seals and engineer flow barriers, with an eye toward making H 2 subsurface storage scalable and geographically agnostic. This suspension can be injected at its initial low viscosity and elasticity into a porous medium, allowing for easy pumping and targeted delivery. Once inside the target zone, it matures into a soft solid with much higher viscosity and elasticity, acting as a potential flow barrier. We discuss the rheological properties of the suspensions and demonstrate that hydrogen does not adversely affect their microstructure, but rather increases the suspensions' viscosity and elasticity. Moreover, the suspensions enhance the rock samples' compressive strength, while hydrogen exposure increases their stiffness and ductility. The ability of rock samples saturated with the suspensions to contain higher injected gas pressures is enhanced by aging at higher temperatures. [Display omitted] • A Laponite-based containment strategy is proposed to create geologic flow barriers. • Low viscosity & elasticity suspensions mature into soft solids within porous media. • Laponite suspensions becomes more viscous and elastic when exposed to hydrogen. • H 2 exposure increases stiffness and ductility of Laponite - saturated rock samples. • This strategy could enable subsurface H 2 storage to be geographically agnostic. [ABSTRACT FROM AUTHOR]