Abstract
A field‐scale carbon dioxide (CO2) injection pilot project was conducted by the Southeast Regional Carbon Sequestration Partnership (SECARB) at Cranfield, Mississippi. Two associated campaigns in 2009 and 2010 were carried out to co‐inject perfluorocarbon tracers (PFTs) and sulfur hexafluoride (SF6) with CO2. Tracers in gas samples from two observation wells were analyzed to construct breakthrough curves. In this work, we present the field data and numerical modeling of the flow and transport of CO2, brine, and tracers. A high‐resolution static model of the formation geology in the detailed area study (DAS) was used to capture the impact of connected flow pathways created by fluvial channels on breakthrough curves and breakthrough times of PFTs and SF6 tracers. We use the cubic‐plus‐association (CPA) equation of state, which takes into account the polar nature of water molecules, to describe the phase behavior of CO2–brine‐tracer mixtures. Our simulated results show good agreement for the 2009 tracer campaign in Cranfield, while a larger discrepancy emerges by 2010. The combination of multiple tracer injection pulses with detailed numerical simulations proves to be a powerful tool in constraining both formation properties and how complex flow paths develop over time.
