MAGNETIC RESONANCE IMAGING OF HYDROCARBON-CONTAMINATED POROUS MEDIA

Nuclear magnetic resonance response measurement is a nondestructive and nonintrusive technique, which is potentially useful for in situ characterization, mapping, and diagnostic purposes in hydrocarbon-contaminated subsurface, including rock. Magnetic resonance measurements of a porous medium allow the determination of necessary parameters to evaluate permeability and porosity of the medium and the type of hydrocarbons present in the pore fluid. This information is of particular importance in evaluation of hydrocarbon transport in contaminated soils. This paper presents the results of a preliminary study intended to evaluate the robustness of the magnetic resonance imaging technology using well-characterized laboratory specimens of porous material containing hydrocarbon liquids. First, a dry uniform sand pack impregnated with an aqueous coal tar mixture was imaged to evaluate discemable hydrocarbon distribution in the pore space of the sand column. Then, packed columns of glass beads of various sizes, permeated with distilled water and trichloroethyiene, were imaged. The discemable images of the pore space and the interface of the two liquids in the pore space indicated that magnetic resonance imaging could be a viable tool to determine spatial distribution and mass fraction of hydrocarbon liquids in contaminated subsurface.