CARBON SEQUESTRATION IN NORTHEAST GEORGIA: POTENTIAL CLAY DISSOLUTION IN THE CAMBRIAN WEISNER QUARTZITE (SANDSTONE)

The Cambrian Weisner Quartzite sandstone from Northeast Georgia is a possible prospect for a reservoir for carbon sequestration. The structure and porosities occur with a cap rock, the Weisner Quartzite as a reservoir rock underneath, and in an anticline, making the sandstone a possible site for carbon sequestration. The purpose of this study is to determine what reactions occur when this Weisner Quartzite is exposed to CO2-rich brines under carbon sequestration conditions. A Parr Bomb with a Teflon cup was used to experimentally reproduce the conditions of the site processes. A 1cm³ sample of the Weisner Quartzite was placed in a brine solution using chemical compositions known from the nearby Pottsville Formation, and dry ice was used as a carbon dioxide source at 1400psi for 120 hours. The brine solution was analyzed before and after Parr Bomb using atomic absorption (AA) spectroscopy. Rock samples were analyzed pre and post Parr Bomb by X-ray fluorescence (XRF) spectroscopy. AA results show an increase in potassium (K) in the brine solution post Parr Bomb. XRF results were used to plot the removal of K and rubidium (Rb) via ratios to zirconium (Zr) and titanium (Ti). For example, the ratios of K₂0 to Rb pre were 0.0051 K₂O/Rb, and post 0.0024 K₂O/Rb. These preliminary results suggest the possibility of dissolution of clay minerals in high pressure, CO2 enhanced brines. This could show a possible gain in secondary porosity of the quartzite under carbon sequestration conditions.