Comparison of Chemical and Hysteresis CO2 Trapping in the Nugget Formation 2

Abstract

Abstract The Moxa Arch Anticline is a regional-scale northwest-trending uplift in western Wyoming and it has been chosen for CO2 capture and storage. The Nugget Sandstone is a deep saline aquifer that has been a candidate for CO2 storage. In this paper we compare the amount of mineral and solution trapping in comparison with dynamic hysteresis trapping based on compositional simulation. To the best of our knowledge this is the first paper to computationally assess the chemical trapping in the Nugget formation and to compare these three trapping mechanisms against each other. Reaction-path and kinetic modeling of CO2–brine–mineral reactions in the Nugget formation was investigated to probe the factors that affect capacity for CO2 chemical trapping. The geochemical simulation of this system was explored in order to assess how mineralogy might change and the relative importance of mineral and solution trapping phenomena through time. Mineral trapping is simulated with both GWB and GEM-GHG. The maximum mineral trapping is 5 g of CO2 per ton of reacted rock, and solution trapping is 3.47 g/kg rock. In comparison, a recent computational study of the Rose Run sandstone, Ohio indicates a much higher mineral trapping capacity, mainly because of reservoir pressure in addition to the presence of glauconite as an iron source for siderite formation. These results reveal that mineral trapping in the Nugget formation is not significant but that total chemical trapping might be much more than that of hysteresis trapping. Therefore, the contribution and importance of chemical trapping in CO2 sequestration should be taken into account for assessment of CO2 sequestration.