Experimental Study of Stationary Processes During Injection of Carbon Dioxide into the Reservoir

This study of CO<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> injection into depletedreservoir analogues investigates H<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> generation, pressure rise, and the role of iron shavings. Column tests with CO<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf>-saturated and unsaturated waters (technical, distilled, artificial seawater <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathbf{3 5 ~ g} / \mathbf{L ~ N a C l}$</tex>) showed fastest H<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> production in technical water and salinity-suppressed kinetics; reactor pressure rose from 24 to <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$23-25 ~\text{atm}$</tex> with a <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\sim 1-2{ }^{\circ} \mathrm{C}$</tex> temperature increase, and gas reached <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\approx 96 \% \mathrm{H}_{2}\left(\text{CO}_{2}&lt;3 \%\right)$</tex> at <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\sim 20.8 ~\text{atm}$</tex> after <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\sim 144 ~\mathrm{h}$</tex>. The apparent water-decomposition rate was <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\sim 4 \times 10^{-5} ~\mathrm{g} \mathrm{H}_{2} \mathrm{O} \cdot \mathrm{h}^{-1} \cdot ~\mathrm{g}^{-1}$</tex>, while iron activity peaked then declined over <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\sim 1500 ~\mathrm{h}$</tex> due to corrosion and passivation. Results highlight the need to control fluid mineralization, monitor pressure, and manage iron-related reactivity for safe CO<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> storage.