Atmospheric and soil-gas monitoring for surface leakage at the San Juan Basin CO2 pilot test site at Pump Canyon New Mexico, using perfluorocarbon tracers, CO2 soil-gas flux and soil-gas hydrocarbons

► Perfluorocarbon tracers were co-injected with CO2 and leakage monitored in soil-gas. ► The femtoliter sensitivity of PFC tracers provided an early detection of leakage. ► EM and VSP surveys were used to evaluate reservoir to surface migration pathways. ► Tracer breakthrough in gas/CO2 offset wells provided data for reservoir modeling. ► Soil-gas depth profiles were use to distinguish barometric pumping from leakage.