Magnetic resonance imaging of hydrocarbon-contaminated porous media

Nuclear magnetic resonance response measurement is a nondestructive and non intrusive technique, which is potentially useful for in situ characterizati on, 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 poro sity of the medium and the type of hydrocarbons present in the pore fluid. This information is of particular importance in evaluation of hydrocarbon t ransport in contaminated soils. This paper presents the results of a prelim inary study intended to evaluate the robustness of the magnetic resonance i maging technology using well-characterized laboratory specimens of porous m aterial containing hydrocarbon liquids. First, a dry uniform sand pack impr egnated with an aqueous coal tar mixture was imaged to evaluate discernable hydrocarbon distribution in the pore space of the sand column. Then, packe d columns of glass beads of various sizes, permeated with distilled water a nd trichloroethylene, were imaged. The discernable images of the pore space and the interface of the two liquids in the pore space indicated that magn etic resonance imaging could be a viable tool to determine spatial distribu tion and mass fraction of hydrocarbon liquids in contaminated subsurface.