THE TIME-TEMPERATURE-STRESS EQUIVALENCE OF CREEP BEHAVIOR OF GELLED CRUDE OIL

The security of waxy crude oil pipeline in the process of stop-restartis severely affected by the rheological properties of gelled crude oil,expecially the viscoelastic creep property. The parameters such as stress, time and temperature have to beconsidered at the same time in describing the viscoelastic behaviorof gelled crude oil. Creep experiments are conductedunder different stresses and temperatures. The results indicate that thechanges of stress and time have similar effects on the creep characteristictime of gelled crude oil. Nonlinearcreep behavior is analyzed by means of the equivalence principle oftime-temperature-stress. The main creep curve under reference stress andreference temperature is obtained, by fittingwith the viscoelastic rheological model. So the long-term creep behaviorunder lower temperature and stress can be predicted by short-term creepbehavior under higher temperature and stress.