Long-term storage or sequestration of anthropogenic "greenhouse gases" such as CO2 is a proposed approach to managing climate change. Deep subsurface brine reservoirs in geological sedimentary basins are possible sites for sequestration, given their ubiquitous nature. The Southwest Regional Partnership on Carbon Sequestration (SWP) is a consortium sponsored by the U.S. Department of Energy and comprises a diverse group of expert organizations specializing in carbon sequestration science and engineering, as well as economics, public policy and outreach. The SWP is designing and deploying several pilot tests to validate the most promising CO2 sequestration technologies and infrastructure concepts, including a major deep saline sequestration demonstration. Study areas include the Uinta and Paradox basins of Utah, the San Juan basin of New Mexico, and the Permian basin of west Texas. The main objective of this aggressive field-testing program is to demonstrate efficacy of proposed sequestration technologies to reduce or offset greenhouse gas emissions in the southwestern U.S.A. Risk mitigation, optimization of monitoring protocols, and effective outreach and communication are additional critical goals of these field validation tests.

For planning and engineering-design purposes, we developed simulation models of each test site, including full coupling of multiphase CO2-groundwater flow, heat flow, and rock deformation, to evaluate potential subsurface impacts of CO2 injection. We also analyzed residence times and migration patterns of CO2 in possible brine reservoir storage sites. Regional-scale hydrologic and mechanical properties, including the presence of fracture zones, were calibrated using laboratory measurements and field data. Our ongoing results suggest that, in general, long-term (~100 years or more) sequestration in deep brine reservoirs is possible, but only if guided by careful site selection and robust data to facilitate quantitative risk assessment and mitigation planning. This presentation will provide details of ongoing results and an associated assessment of the viability of commercial-scale sequestration.