Methodology to assess groundwater quality during CO2 injection at the Quest CCS project

Summary Demonstrating to stakeholders that injected CO2 is safely contained within a storage complex is a key aspect of any Carbon Capture and Storage (CCS) project. At the Quest CCS project, a comprehensive study (pre-injection) was undertaken to develop hydro(geo)logical and hydrogeochemical models of the Quest Sequestration Lease Area from ground surface to base of groundwater protection. These models form an essential framework for assessing groundwater quality during the CO2 injection phase. A number of key analytes were identified to be included in on-going monitoring for containment assessment and assurance monitoring purposes during CO2 injection. Descriptive statistics were used to assess the data and to establish baseline ranges for parameters of interest. This allowed to define and to establish project specific triggers being applicable to either aquifers or individual wells. In order to optimize evaluation of groundwater data collected during the injection phase a semi-automated ArcGIS workflow will be implemented.