关键词: 含蜡原油, 振荡剪切, 粘弹性, 胶凝温度, 实验研究

Abstract: The gelation extent and structure strength can be revealed by the viscoelastic parameters and gelation temperature measured by small amplitude oscillatory shear experiment. A series of oscillatory shear experiments were conducted to measure the viscoelastic parameters of Daqing crude oil with a stress-controlled rheometer RSH150. The results showed that the storage modulus and loss modulus increased in an exponential fashion as the test temperature was reduced. There existed a worst heating temperature for the rheological behavior. The strength of waxy structure and gelation temperature decreased when increasing cooling rate. At the same shear temperature, the strength of waxy structure decreased rapidly and finally tended to a steady state as the energy dissipation of viscous flow increased. Under the same energy dissipation of viscous flow, when the shear temperature was close to the measuring temperature, the low storage modulus, loss modulus and gelation temperature would emerge. When the shear temperature was close to or higher than abnormal point, the viscoelastic parameters varied little with the shear temperature. The recovery of sheared waxy structure displayed an irreversible property.

Key words: waxy crude oil, oscillatory shear, viscoelasticity, gelation temperature, experimental study