Physical Characteristics of Natural Films Formed at Crude Oil-Water Interfaces

Interfacial films have frequently been observed at interfaces between certain crude oils and water. Several investigators have postulated that the presence of these films should influence the efficiency of oil recovery in water-drive or waterflood operations. They may also influence the stability of emulsions, which are sometimes a problem in petroleum production, and may be a factor in the formation of paraffin deposits in oil-well tubing and flow lines. A modified Langmuir film balance was used to study the compressibility and the collapse pressure of these natural interfacial fims. Data developed are used to infer the phase state of the film as a function of such variables as rate of reduction of interfacial area, ionic composition of the substrate, and pH of the substrate. A film of known physical characteristics is shown to have a significant effect on oil recovery from an unconsolidated sand pack. (22 refs.)