Analysis of signal-to-noise ratio of delta C-13-CO2 measurements at carbon capture, utilization and storage injection sites

摘要

As new regulations from the United States Environmental Protection Agency require monitoring and accounting for Class VI injection wells, determining the efficacy of monitoring techniques is a crucial barrier to wide scale carbon capture, utilization and storage (CCUS) deployment. The monitoring of CO2 injection sites to ensure safety and operational success requires high temporal resolution CO2 concentration and carbon isotopic (delta C-13) measurements. As rapid measurement of delta C-13 is not possible with standard isotope ratio mass spectrometry (IRMS), we have developed a methodology using cavity ring-down spectroscopy (CRDS) with a manifold system in order to obtain accurate rapid measurements from a large sample area over an extended study period. A modified Picarro G1101-i CRDS with updated software and an auxiliary laser allows for rapid and continuous field measurement of concentrations and delta C-13 of carbon dioxide as well as concentrations of water and methane. A manifold system actuated by a 16 position valve allows for an increased sampling region and internet connectivity and software developments permit immediate access to data from a remote location. At a field site in Texas where preparations have been underway for enhanced oil recovery (EOR) operations, we have been able to observe biogenic effects on a diurnal scale, as well as variation due to precipitation and seasonality. Our system has proven field readiness for the monitoring of sites with modest CO2 flux. These data have been used to improve leak detection thresholds by an order of magnitude over published models. (C) 2015 Elsevier Ltd. All rights reserved.