Air Foams for Mobility Control and Subsurface Storage of Hydrogen in Porous Media: An Experimental Study

Abstract

This study initially explores and reports the feasibility of surfactant foams to increase the efficacy of hydrogen storage in porous media. This is an essential field of study, which aims to tackle a primary concern of the future hydrogen-based economy-hydrogen storage, which is essential for the supply of energy during periods of intermittent supply. For this, storage of hydrogen in porous media is explored wherein non-uniform front advance and superior gas mobility reduce storage efficacy. To mitigate this concern, the foam was prepared using compressed air and a non-ionic surfactant, Triton X-100, in a guar gum solution of 4000 ppm. A fabricated sand-pack, prepared from the sand of size 100−180 μm, was used as porous media, in which hydrogen storage was evaluated for a fixed flow rate of 30 mL/h as a function of varying slug sizes. The inclusion of foam as mobility control fluid massively increased hydrogen storage by a factor of 1.5−2.7, with slug size 0.5 PV being the most desirable. Enhanced hydrogen storage was obtained when a slug of 0.3 PV or greater was used. Altering the gas flow rate from 30 to 60 mL/h reduced hydrogen storage by 34%. The presence of crude oil reduces foam stability, and the injection and storage of hydrogen gas in depleted oilfields having high volume of crude oil is thus not recommended. This study promotes the use of surfactant foams for subsurface storage of hydrogen in sandstone media by controlling the mobility of injected gas.

Relative Permeability of Hydrogen and Aqueous Brines in Sandstones and Carbonates at Reservoir Conditions

“…The storage and extraction of H 2 requires displacing existing brine‐hydrocarbons and this will be affected by individual reservoir conditions at each site. In particular, the heterogeneity of the porous medium and the transport properties of the H 2 impact the injection and withdrawal cycles, and need to be accurately simulated to maximize storage and production efficiency (Chaturvedi et al., 2022; Mohammadmoradi & Kantzas, 2018). Accordingly, the behavior of injected hydrogen should be studied in terms of its mobility and multiphase flow properties (Iglauer et al., 2022; Razavifar et al., 2021; Sedev et al., 2022).…”

Pore-scale imaging of hydrogen displacement and trapping in porous media

“…10): The IFT of H 2 reduces with depth whereas the H 2 viscosity increases, both of which in theory should augment the displacement of H 2 with water and reduce the S nwr [66,67]. However, increased S nwr with decreasing IFT and increasing viscosity has also been demonstrated [68] which may be due to a simultaneously increased likelihood of unstable displacement/non-uniform fronts [69,70] during both drainage and imbibition processes at decreasing IFT and increasing viscosity, based on the augmenting effect of both parameters on N C (Eq. ( 1)).…”

Pore-scale imaging of hydrogen displacement and trapping in porous media

“…10): The IFT of H2 reduces with depth whereas the H2 viscosity increases, both of which in theory should augment the displacement of H2 with water and reduce the Snwr 62,63 . However, increased Snwr with decreasing IFT and increasing viscosity has also been demonstrated 64 which may be due to a simultaneously increased likelihood of unstable displacement/ non-uniform fronts 10,65 during both drainage and imbibition processes at decreasing IFT and increasing viscosity, based on the augmenting effect of both parameters on NC (Eq. 1).…”

“…It has been postulated that the low viscosity of H2 will cause the gas to travel swiftly, making it little suitable for displacing brine 10 and causing low H2 injectivity. In this work, we showed that from an injectivity and recovery perspective, untreated Clashach sandstone is suitable for underground H2 storage.…”

“…Underground storage of H2 in salt caverns is an established technology 5 , yet, only subsurface porous media (saline aquifers and depleted oil and gas fields), can provide TWh storage capacities that could balance seasonal demands 4 . Relative to cavern storage, inter-seasonal storage in porous media is poorly understood and introduces a range of other complexities 2 , including potential poreclogging by microbial growth 6 , gas loss out of diffuse lateral boundaries, viscous fingering of H2 into reservoir brines, residual trapping and possible reactions with the primary formation fluid and reservoir minerals [7][8][9][10] . Each of these requires consideration of multiphase flow, transport and reaction 2,8 .…”