1134397 Clarens/1133849 Peters Geologic carbon sequestration (GCS) is likely to play an important role in near-term efforts to provide carbon-neutral energy even though it has not yet been definitively demonstrated that CO2 injected into deep geologic formations will stay in place. This project assembles an interdisciplinary partnership to study the conditions that drive or inhibit leakage of CO2 through formation caprocks and the buoyancy-driven transport of CO2 through both caprocks and porous media. This integrated and multidisciplinary effort will generate experimental data to bridge the gap between bench-scale work on geochemical reactions and kilometer-scale simulations of GCS in the real world. Central to the proposed multiscale study are two novel high-pressure experimental test beds: a core-scale (cm-scale) vessel to study reaction and flow in caprock specimens (at Princeton), and a large-scale (6 m) pressurized column in which vertical flow of CO2 will be observed in sedimentary media (at the University of Virginia (UVA)). This approach will integrate experimental observation with two key tools for observation and inference: (1) a suite of lab- and synchrotron-based imaging methods to elucidate and quantify mineral reactions and alterations in pores/fractures (at Brookhaven National Lab (BNL)), and (2) reactive transport modeling to infer reaction rates, build predictive capacity, and conduct numerical experiments. The work is targeted to provide new insight critical to understanding the processes that will ultimately determine the viability of GCS. These processes are poorly understood because it is challenging to study reactions and two-phase flow in an integrated way, under high-pressure conditions, over realistic length scales. Reactions in heterogeneous media are best observed at small spatial scales (nm to μm), while flow is best observed over large scales (m to km). This project will elucidate the interrelation of these processes and provide answers to many of the persistent questions in the field such as: What are the conditions that lead to erosion or self-sealing of caprock flow paths? How do geochemical alterations of mineral surfaces alter CO2 flow? Will long-range buoyant CO2 flow be accelerated or decelerated by complexities in capillarity, viscosity, solubility, and Joule-Thomson cooling? These questions cannot be answered effectively by any single discipline. The project interdisciplinary team combines the expertise of an environmental engineer and expert in high-pressure fluid phase behavior (AFC), a geoenvironmental engineer with over a decade of experience in GCS research (CAP) and a geochemist with over 15 years of experience in advanced x-ray imaging techniques (JPF). This research will achieve broader impacts by identifying critical factors that determine the safe and effective sequestration of CO2 in deep geological reservoirs. The work will provide critical inputs to the effort of the United States to achieve the 2010 Presidential directive of overcoming the barriers to the widespread deployment of CCS within ten years. Furthermore, the experimental test beds constitute an investment in long-term study of CO2 flow and reaction in porous and fractured media. Lessons learned from these experiments can be applied to the design of larger facilities currently under development. The research also represents an effort to introduce global environmental change and carbon-neutral energy into the curricula at UVa and Princeton, and to use Brookhaven?s InSync outreach program to enable high school students to have remote access to experimental time at a synchrotron-based x-ray imaging facility.