Reply to comments by Schnaar et al. on 'Brine flow up a well caused by pressure perturbation from geologic carbon sequestration: Static and dynamic evaluations' by Birkholzer et al. (2011)

摘要

We are thankful to Schnaar et al. (2013) for pointing to a necessary correction in Birkholzer et al. (2011), where methods were presented for estimating the Area of Review (AoR) surrounding a carbon dioxide injection well used for the purpose of geologic sequestration. Determining this area is a requirement in the US Environmental Protection Agency's federal regulations for geologic sequestration injection wells (USEPA, 2010). The AoR refers to the region surrounding the CO2 injection well(s) wherein the potential exists for groundwater resources to be endangered by the leakage of CO2 and/or the upward migration of formation brine. According to USEPA (2013), the size of an AoR is defined by the outer composite of two partially overlapping regions: (1) the region overlying the maximum extent of free-phase CO2 in the injection formation, to account for the possibility of buoyancy-driven CO2 leakage and (2) the region with fluid-pressure increase in the injection formation above a given critical pressure value, to account for the possibility of pressure-driven brine/CO2 leakage.