Friberg Correlations in Oil Recovery

Abstract

The current status of “Friberg correlations” is reviewed and illustrated in model and industrial systems relevant to the oil industry. For a model naphthenic acids/sodium hydroxide two‐phase system, a third, liquid crystal (LC), phase is formed at the o/w interface from sodium naphthenates, which is produced in situ by a chemical reaction. This LC layer spreads spontaneously on the o/w interface, thus it is a “surface‐active phase” in the sense defined by R. G. Laughlin. When this additional phase covers the oil/water interface it modifies the transport processes throughout the interface. The LC layers on water droplets may be one of the reasons for the high water‐in‐oil emulsion stability observed in industrial systems. This suggestion is supported by the increased stability of water‐in‐bitumen emulsions doped with sodium naphthenates at concentrations higher than 50 ppm. The stability of the emulsion droplets can be further enhanced by capturing solid particles or precipitated asphaltenes at the LC‐coated interfaces. At equilibrium, optically anisotropic structures are detected in the bitumen/water/sodium hydroxide system, indicating the presence of a liquid crystal (LC) phase in industrial systems. The possible source of errors and proper use of polarization microscopy are discussed for LC phase containing emulsions.

Keywords:

• Polarization microscopy
• liquid crystal
• crude oil
• naphthenic acids
• emulsion stability

Acknowledgments

Financial support provided through NSERC Industrial Research Chair in Oil Sands Engineering (J. H. Masliyah) is gratefully acknowledged. The authors would also like to thank Howie Zhang for the dewatering efficiency investigations and Robert Skwarok (Syncrude Research Center, Edmonton) for his help with image processing. Measurements carried out at Syncrude Research Center are appreciated.