Pore Connectivity in Hanford Sediments and Natural Rock
EMSL Project ID
40078
Abstract
Pore connectivity in natural sediments and rock has important short- and long-term effects on fluid flow and chemical transport. These effects have implications for the remediation of contaminated sites, recovery of gas and oil, as well as the repository performance of geological formations for carbon sequestration and storing high-level nuclear waste. Moreover, the issue of pore connectivity, and its emergent macroscopic effects on flow and transport, has significant theoretical importance. For example, solute diffusion in sparsely-connected pore spaces will not be described by classical Fickian behavior; anomalous behavior is observed. Our preliminary work suggests that low-connectivity rocks are common, which may explain some of the scale issues that have plagued hydrogeologists. We have also found that fluid flow and solute transport in rock with low pore connectivity can be characterized as a percolation problem, and the use of percolation theory and pore-scale network modeling approach will help derive specific mathematical tools for up-scaling from laboratory core scale to in-situ field scales. The research objectives of this work are to assess the prevalence, and quantify the magnitude, of low pore connectivity in Hanford sediments and a variety of natural rock. We will use the X-ray computed tomography (a new instrument at EMSL) and scanning electron microscopy available at EMSL to examine the pore connectivity of geological media. These approaches will complement several other techniques - water imbibition, laser ablation-ICP-MS to identify edge-accessible porosity, and pore-scale network modeling - that we have been using to probe pore connectivity. Insights grained from these other techniques will guide the choices of samples to be examined at EMSL. Overall, the research will provide a theoretical understanding of pore connectivity effects on fluid flow and solute transport process, applicable to the feasibility and performance of remediation approaches and carbon sequestration in geological formations.
Project Details
Project type
Large-Scale EMSL Research
Start Date
2010-10-26
End Date
2012-09-30
Status
Closed
Released Data Link
Team
Principal Investigator
Team Members
Related Publications
Hu Q, RP Ewing, and S Dultz. 2012. "Low Pore Connectivity in Natural Rock." Journal of Contaminant Hydrology 133:76-83. doi:10.1016/j.jconhyd.2012.03.006
Peng S, Q Hu, S Dultz, and M Zhang. 2012. "Using X-Ray Computed Tomography in Pore Structure Characterization for a Berea Sandstone: Resolution Effect." Journal of Hydrology 472-473:254-261. doi:10.1016/j.jhydrol.2012.09.034