Blasingame decline theory for hydrogen storage capacity estimation in shale gas reservoirs

Hydrogen Underground Storage in Silica-Clay Shales: Experimental and Density Functional Theory Investigation

“…18,19 Like shale gas, there are three possible states for hydrogen gas: free, adsorbed, and dissolved. 14 Hence, hydrogen, with its low density and high diffusivity, 1 can pass through fractures and crevices in caprock, 20 causing H 2 loss. Therefore, the adsorption of hydrogen gas in depleted shale gas formations, maintaining adsorbed methane inside the porous structure can be more secure and thus derisk the challenge of H 2 loss.…”

“…1,11−13 In addition, the depleted shale gas reservoirs are considered a potential site for H 2 storage alongside conventional storage reservoirs, due to their tight porosity and permeability, broad distribution, and increased capillary pressures, which could either make it difficult for hydrogen to leave, or significantly slow down its passage and its large volume. 14,15 Shale gas reservoirs are sophisticated heterogeneous porous substances, made from two components: organic matter (carbonaceous kerogen) and inorganic minerals. 16 Shale's inorganic component primarily comprises quartz (silica), calcite, feldspar, and clay minerals.…”

“…However, storing a significant amount of hydrogen for a lengthy period, as a supplementary energy source, has been challenging . To address this issue, conventional underground geological storage such as depleted oil and gas reservoirs, aquifers, or caverns are potential candidates. , Mainly, depleted gas reservoirs are considered the most viable alternative from technological (ample storage capacity) and economic perspectives. ,− In addition, the depleted shale gas reservoirs are considered a potential site for H 2 storage alongside conventional storage reservoirs, due to their tight porosity and permeability, broad distribution, and increased capillary pressures, which could either make it difficult for hydrogen to leave, or significantly slow down its passage and its large volume. , Shale gas reservoirs are sophisticated heterogeneous porous substances, made from two components: organic matter (carbonaceous kerogen) and inorganic minerals . Shale’s inorganic component primarily comprises quartz (silica), calcite, feldspar, and clay minerals.…”

“…Like shale gas, there are three possible states for hydrogen gas: free, adsorbed, and dissolved . Hence, hydrogen, with its low density and high diffusivity, can pass through fractures and crevices in caprock, causing H 2 loss.…”