Near-Surface Monitoring Strategies for Geologic Carbon Dioxide Storage Verification

摘要

Geologic carbon sequestration is the capture of anthropogenic CO2, typically separated from industrial and power-plant flue gases, and its storage in deep underground formations such as depleted oil and gas reservoirs and deep brine-filled formations. The purpose of geologic carbon sequestration is to reduce net atmospheric emissions of CO2 to mitigate potential climate change associated with the role of CO2 as a greenhouse gas. In order to ensure that geologic CO2 storage is effective, monitoring of CO2 storage sites will have to be carried out to verify that CO2 is not leaking from the intended storage site, migrating to the near-surface environment, and seeping out of the ground. The purpose of this report is to discuss CO2 storage verification by monitoring and analysis of the near-surface environment. To this end, we (1) present a discussion of the properties of CO2 and implications for CO2 transport in the near-surface region, (2) summarize model simulations of CO2 leakage and seepage that establish some fundamental features of the process, (3) present a summary of processes that affect natural background CO2 fluxes and concentrations within which the LOSS will have to be discerned, (4) present a summary of instrumentation that is currently available or potentially available in the future to monitor CO2 leakage and seepage in the near-surface environment, and (5) discuss potential strategies and approaches that use existing instrumentation to discern CO2 LOSS from the naturally varying background fluxes and concentrations associated with the carbon cycle.