| The purpose of the present work was to examine the effects of asphaltenes, amphiphilic molecules found in crude oils, on subsurface contamination by petroleum liquids. Initial experiments were conducted, using naphthalene as a representative target contaminant, to determine the contaminant equilibrium partitioning relationships in an asphaltene-oil-water system.; Further experiments were conducted to determine if the presence of asphaltenes in petroleum liquids affected resistance to interphase mass transfer of naphthalene in situ with aging. Results were analyzed using a lumped mass transfer coefficient calculated after various aging periods. Experimental data suggested that adding increasing amounts of asphaltenes to gasoline resulted in a marked increase in the lumped mass transfer coefficient with time during aging periods of up to 12 days. Over a 60-day aging period, amended gasolines were found to show net decreases in the lumped mass transfer coefficients, while non-amended gasolines showed a rather constant lumped mass transfer coefficient over the entire aging process.; Finally, residual saturation centrifuge tests were conducted to determine if the presence of asphaltene in petroleum liquids affected the wettability of a subsurface system contaminated with gasolines containing various concentrations of asphaltenes. Observation of the systems after centrifuging suggested that as the asphaltene content in gasoline was increased, oil recovery from the porous media decreased. (Abstract shortened by UMI.)... |
