GEOCHEMICAL INVESTIGATION AND HYDROCHEMICAL CHARACTERIZATION FOR CARBON CAPTURE AND STORAGE, CUTTER WELL SITE, KANSAS

A class VI permit U.S. Department of Energy site has been proposed for carbon sequestration in south-central Kansas. In an effort to maintain environmental stability three wells have been drilled to basement rock, two being near the injection site, and one being to the western annex. The western annex site, Cutter, will be utilized as a cross-comparison for mineralogical, geochemical, and structural components to the eastern sites in Wellington. A link will be determined of the continuity of three zones of interest: the Mississippian pay zone, a potential baffle zone, and the injection zone. Injection will occur in the regional Arbuckle saline aquifer, a dolomitic carbonate at a depth of 4100-5100 feet. The Mississippian pay zone could allow for revenue for the project using secondary oil and gas recovery. The potential baffle zone could segregate and impede vertical migration of the injected CO­­₂. 11 depths within Cutter have been swabbed, and samples taken to investigate the chemistry of the subsurface formation water. The different depths will allow for a quantitative determination of how the brine composition varies with depth, and also provides a baseline for future monitoring. Initial chemical analysis by ICP-OES and HR-ICP-MS show a hyper saline brine (50,000-190,000TDS), dominated by Cl, Na, and Ca ions. pH ranges from 6.4 to 7.5, and total alkalinity from 124 and 378 mg/L of HCO­₃^-. One complex, yet intriguing, species is Iron. It could potentially allow for further precipitation of the CO_2­ from the formation of Fe carbonates, such as siderite. Flow through experiments conducted in order to determine reactivity and stability of the overlying cap rocks and baffle zone. Reservoir characterization is determined through geochemical modeling, and will need to be extensively studied in order to properly determine the feasibility for carbon sequestration in Kansas. With the potential for 2.7 billion tones of CO₂ to be stored in Kansas, (Carr, 2005) this project could allow Kansas to play a major role in the quest for environmental stability.