Mapping and quantifying CO2 leakage using the Ground CO2 Mapper

Abstract

The standard method for mapping and quantifying CO2 leakage flux from the ground surface to the atmosphere involves performing numerous point flux measurements using the accumulation chamber technique and then applying geostatistical interpolation to infer spatial distribution and estimate total mass transfer. Monte Carlo simulations using the program MCFlux have recently demonstrated, however, that uncertainty in the resultant estimate can be large if the chosen sample spacing is insufficient to capture the spatial complexity and size distribution of the leakage anomalies. In an effort to reduce this uncertainty we have developed a new tool, called the Ground CO2 Mapper, that rapidly measures the concentration of CO2 at the ground surface as a proxy for flux. Recently published results have illustrated the capabilities of the Mapper in terms of sensitivity and spatial resolution, as well as possible influencing parameters such as wind strength. The present work examines the potential of combining Mapper results with point flux measurements (using multivariate geostatistics) to improve data interpretation, with the MCFlux program being used once again to assess uncertainty in the final estimates.

Keywords: CCS, monitoring, leakage, CO2, flux quantification