资源环境科技发展态势分析平台

Tracers are used to tag the injected carbon dioxide (CO₂) for verification of the storage performance and containment in geosequestration. Yet the characterization of the transport behavior of a chemical tracer in two‐phase flow system have not been fully investigated. We present experimental observations together with numerical results for both homogeneous and heterogeneous media from core‐scale to field‐scale. The key features of the breakthrough curves (BTCs) that include the tracer arrival time, peak concentration, and tailing pattern were examined. We identify distinct differences in BTCs depending on whether the formation was previously swept by CO₂. When the tracer is released before CO₂ sweeps the formation, the tracer transports at the front of gas‐liquid interfaces with a narrow tracer plume distribution and the BTCs reflect the effect of local heterogeneity. Furthermore, a series of tracer pulse can be used to identify whether new pathways have been developed during CO₂ injection.