NETL is partnering with Southern Illinois University (SIU) to undertake a comprehensive study to understand the potential interactions between organic rocks and CO2. Interactions between various ranked coals (lignite, sub-bituminous, bituminous, and anthracite) or organic shale with CO2 are complex and not well understood. The fact that potential risks associated with their storage are seldom evaluated under plausible but extreme transient conditions poses a concern. Most risk assessments are typically accomplished under equilibrium conditions. However, under extreme non-equilibrium conditions (whether natural, seismic, or manmade) there are potential situations that could lead to the re-emission of CO2 stored in organic rocks. The possible interactions have not yet been studied in detail. In addition, SIU is attempting to evaluate how potential pressure and temperature variations, typically encountered under natural seismic conditions, can control the emission, adsorption, and absorption behavior of stored CO2.
Fundamental and applied research on carbon capture, utilization and storage (CCUS) technologies is necessary in preparation for future commercial deployment. These technologies offer great potential for mitigating carbon dioxide (CO2) emissions into the atmosphere without adversely influencing energy use or hindering economic growth. Deploying these technologies in commercial-scale applications requires a significantly expanded workforce trained in various CCUS technical and non-technical disciplines that are currently under-represented in the United States. Education and training activities are needed to develop a future generation of geologists, scientists, and engineers who possess the skills required for implementing and deploying CCUS technologies. The U.S. Department of Energy’s (DOE) National Energy Technology Laboratory (NETL), through funding provided by the American Recovery and Reinvestment Act (ARRA) of 2009, manages 43 projects that received more than $12.7 million in funding. The focus of these projects has been to conduct geologic storage training and support fundamental research projects for graduate and undergraduate students throughout the United States. These projects include such critical topics as simulation and risk assessment; monitoring, verification, and accounting (MVA); geological related analytical tools; methods to interpret geophysical models; well completion and integrity for long-term CO2 storage; and CO2 capture.
Under seismic conditions, whether natural or manmade, equilibrium condition monitoring may not provide adequate information to evaluate the potential for CO2 to be permanently stored in the subsurface. This research is providing the framework to understand and determine how the interactions between organic rocks and CO2 affect the strength of the rocks, and whether these interactions pose a potential for rock collapse under overburden stresses and pore pressures. In addition, the research is evaluating whether CO2-saturated organic rocks may indicate leakage of CO2 over time when placed under typical overburden stresses and how shock pressure waves in CO2-saturated organic rocks control the interactions between adsorbed and/or absorbed CO2 and rock; how these interactions are modified, and if there is cause for concern due to significant CO2 leakage. Finally, the research is evaluating whether CO2-saturated organic rocks placed under typical overburden stresses could potentially leak CO2 when subjected to shock-induced variations in hydrostatic pressure. The research effort provides students the opportunity to develop skills that are vital to CCUS operations, including geologic characterization activities, CO2 storage capacity estimation, and CO2 storage permanence.
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