Tracer Studies

Tracer studies use environmental and artificial ‘tracers’ to understand transport properties in vadose, groundwater, CO2 sequestration and hydrocarbon settings. In our laboratory we conduct benchtop-scale flow-through column experiments to understand the interaction between gases and solid substrates. Carbon, hydrogen, and oxygen isotope measurements are coupled to concentration measurements to better define diffusion and adsorption parameters.&delta

Cumulative breakthrough curve for CO2 illite.1-D column experiment using 1/4″ stainless steel tubing and a mass flow controller Crushed illite used in tracer experiments.Crushed illite used in carbon dioxide tracer experiment

Column Experiments

We developed a plug-flow experimental reactor to verify parameters used in adsorption isotherm models. This system is optimized to monitor transport of CO2 and CH4 through porous and non-porous media. This system can simultaneously measure concentration and carbon isotope values of the gas samples through time. The current system permits sampling at 5 minute intervals.
Our new system (due to be installed September, 2012) is capable of simultaneous Noble gas, CO2 and methane analysis. This will allow us to explore competitive adsorption processes and better identify tracer properties.

Inverse Modeling
Data from column experiments are modeled using mass transfer equations that include parameters for diffusion, porous media effects, and adsorption. Inverse modeling can be used to estimate parameters governing these equations. Matlab is used ‘best fit’ nonlinear equations and estimate

crushed sand used in 1-D column experiment

crushed sand used in 1-D column experiment