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Commercial scale decarbonization through carbon capture and storage may likely involve many CO2 storage projects located in close proximity. The close proximity could raise concerns over caprock integrity associated with reservoir pressure buildup and interference among adjacent projects. Commercial-scale injection will also require large prospective CO2 storage resource and high injectivity in the targeted storage formations. To accommodate the need for both large resource and high injectivity, project operators could consider injecting CO2 into a stacked sequence of formations. This analysis investigates the benefits of injecting CO2 into a vertically stacked sequence of saline formations, over injecting the same amount of CO2 into a single saline formation, in addressing these challenges. Our analysis shows that injecting into the stacked sequence mitigates the extent of pressure buildup among the stacked formations, while still achieving the same or greater target CO2 storage volumes. Among cases modeled, the resulting pressure buildup front is most reduced when each storage site distributes injection volumes over several wells, each of which injects a portion of the total CO2 mass across the stacked sequence. This favorable case not only results in the smallest CO2 aerial footprint, but also shows the largest reduction in the pressure buildup at the top of perforation at the injection wells (upwards of approximately 46% compared to the single-formation storage), the result of which is crucial to maintain caprock integrity. This analysis provides insights into required decision-making when considering multi-project deployment in a shared basin. [ABSTRACT FROM AUTHOR]

As high CO2-emitting utilities and other industries move toward implementing carbon capture and storage (CCS) technologies to manage greenhouse gas emissions, more and more CO2 will become available as a resource for multiple applications. CO2 will be a plentiful potential feedstock (carbon source) for many products, including commercial chemicals, plastics, and improved cement. Unfortunately, CO2 is a stable compound with a low energy state and does not readily participate in chemical reactions without added energy. Additionally, the supply of CO2 that may be available as the USA moves toward a carbon-constrained economy far exceeds the current demand for CO2 as a commodity chemical. Thus, identifying candidate chemistries and economically feasible approaches that utilize large amounts of CO2 as a feedstock for high-demand products is very challenging. The United States Department of Energy (DOE), through its National Energy Technology Laboratory (NETL), has an active carbon sequestration program. The goal of the CO2 Utilization Focus Area is to identify and develop a suite of technologies that can beneficially use CO2 to produce useful products that can generate revenue to offset capture costs associated with CCS implementation, contribute to CO2 emissions reductions, and reduce the demand for petroleum based feedstocks and products. Currently, projects being supported fall into the categories of (i) enhanced hydrocarbon recovery, (ii) chemicals production, (iii) mineralization processes for building products, and (iv) plastics production. This perspective discusses the current status of CO2 use and presents a review of DOE's program to identify and demonstrate uses for captured CO2. © 2011 Society of Chemical Industry and John Wiley & Sons, Ltd [ABSTRACT FROM AUTHOR]