Nanoparticle Transport Through Fractures And Heterogeneous Porous Media
Nanoparticles have a diffusion constant a couple of orders of magnitude smaller than inert chemical tracers such as potassium bromide (KBr), and this means that they can potentially be used to measure the degree to which subsurface flow occurs through fractures and high permeable zones in heterogeneous porous media. Using carbon based 2-5 nm particles (C-Dots); we inject dual tracers at different flow rates into a permeable core channel (fracture). The KBr tracer has time to diffuse into the surrounding halo much more than the particle tracer and arrives much later in the effluent. We carry out this kind of experiment in laboratory apparatus with different geometry (Hele-Shaw fracture cell, Rectangular and Cylindrical Beadpack columns). The Interpretation required models that take into account the flow in the halo as well as the core and, which also include dispersion. All experiments could be interpreted in a consistent fashion. The success suggests that it may be possible to assess the extent of fracture-controlled flow in the subsurface by combining non-sticking nanoparticles with an inert chemical tracer.
nanoparticle transport; heterogeneous porous media; fluid bypass
Cathles, Lawrence M
Archer, Lynden A.
M.S., Geological Sciences
Master of Science
dissertation or thesis