Carbon-capture and sequestration (CCS) in geologic reservoirs is one strategy for reducing anthropogenic CO2 emissions from large-scale point source emitters. Recent developments have shown that basalt reservoirs are highly effective for permanent mineral trapping on the basis of CO2-water-rock interactions, which result in the formation of carbonate minerals. However, the injection of super-critical CO2 into the subsurface causes a disturbance in the pressure, temperature, and chemical systems within the target reservoir. How the ambient conditions change in response to a CO2 injection ultimately affects the transport and fate of the injected CO2. Understanding the behavior and transport of CO2 within a geologic reservoir is a difficult problem that is only exacerbated by heterogeneities within the reservoir; for example, permeability can be highly heterogeneous and exhibits significant control on the movement of CO2. This work is focused on constraining the permeability uncertainty within a flood basalt reservoir, specifically the Columbia River Basalt Group (CRBG). In order to do so, this dissertation is a culmination of four projects: (1) a geostatistical analysis resulting in a spatial correlation model of regional scale permeability within the CRBG, (2) a Monte Carlo-type modeling studying investigating the effects that permeability uncertainty has on the injectivity and storativity of the CRBG as a storage reservoir, (3) a modeling study utilizing 1-, 2-, and 3-D numerical models to investigate how the thermal signature of the CO2-water system evolves during a CO2 injection, and (4) a Monte Carlo-type modeling study focused on the integrity of the CRBG as a CO2 storage reservoir through a probabilistic assessment of static threshold criteria. / Doctor of Philosophy / The process of capturing CO2 from point-source emitters, such as power plants and injecting that CO2 into a geologic formation is one way to reduce anthropogenic CO2 emissions. Recent field studies have shown that basalt reservoirs may be very effective at permanently storing the injected CO2 making them a secure geologic formation to store the CO2. However, basalt reservoirs can be highly fractured, which causes the properties of the reservoir (e.g. permeability, porosity, etc.) to be nonuniform. Having nonuniform reservoir properties creates uncertainty when planning a large-scale CO2 injection. This research is focused on understanding and constraining the uncertainty of nonuniform reservoir properties associated with a large-scale CO2 injection. The work presented utilizes a geostatistical analysis of permeability to inform a variety of numerical models to study how nonuniform reservoir properties affect CO2 injection rate, how much CO2 can be stored, how the pressure and temperature of the reservoir changes, and how secure the storage reservoir is during a CO2 injection.