Rheological Properties of Model and Crude Oil Systems when Wax Precipitate under Quiescent and Flowing Conditions

Wax precipitation and deposition is a recurring challenge in transportation of crude oil, and increased knowledge about the behavior of such systems is necessary. Microscopy and differential scanning calorimetry were used to follow the crystallisation of wax for two model systems. The amount of solid was also determined by the latter method as well. The flow and viscoelastic behavior were investigated around the wax precipitation temperature, and the yield stress was determined both after dynamic and static cooling. Interpretation of the results was carried out in view of crystal growth and microstructure of the wax crystals. The variables that were studied were wax composition, amount of wax and thermal and shear history.

Keywords:

• Rheology
• yield stress
• static and dynamic cooling
• wax precipitation
• crude oil

S.C. acknowledges the joint industrial consortium “Particle Stabilised Emulsions/Heavy Crude Oils” for financial support. The two model waxes were kindly supplied by H. Oschman, Champion Technologies.