Petroleum Science >2013,??Issue 3:??395-401 DOI: https://doi.org/10.1007/s12182-013-0287-0
Modeling the viscoelasto-plastic behavior ofwaxy crude Open?Access
文章信息
作者：Teng Houxing and Zhang Jinjun
作者單位：
National Engineering Laboratory for Pipeline Safety/Beijing Key Laboratory of Oil and Gas Distribution Technology, China University of Petroleum, Beijing 102249, China;National Engineering Laboratory for Pipeline Safety/Beijing Key Laboratory of Oil and Gas Distribution Technology, China University of Petroleum, Beijing 102249, China
投稿時間：2013-01-04
引用方式：Teng, H. & Zhang, J. Pet. Sci. (2013) 10: 395. https://doi.org/10.1007/s12182-013-0287-0
文章摘要
Waxy crude oil exhibits complex rheological behavior below the pour point temperature,
such as viscoelasticity, yield stress, and thixotropy, owing to the formation of a three-dimensional
spongelike interlock network structure. This viscoelasto-thixotropic behavior is an important rheological
behavior of waxy crude oils, determining the flow recovery and safe restart of crude oil pipelines. Up to
now, the thixotropic models for waxy crude have been all viscoplastic models, without considering the
viscoelastic part before the yield point. In this work, based on analyzing the variation of the elastic stress
and viscous stress in the Mujumbar model, a new viscoelasto-plastic model is proposed, whose shear
stress is separated into an elastic component and a viscous component. The elastic stress is the product
of the shear modulus and elastic strain; the shear modulus is proportional to the structural parameter. For
the elastic strain, we followed the line of Zhu and his coauthors and assumed that it may be expressed
by an algebraic equation. The model is validated by stepwise shear rate tests and hysteresis loop tests on
Daqing and Zhongyuan waxy crude. The results show that the model’s fitting and predictive capability is
satisfactory.
such as viscoelasticity, yield stress, and thixotropy, owing to the formation of a three-dimensional
spongelike interlock network structure. This viscoelasto-thixotropic behavior is an important rheological
behavior of waxy crude oils, determining the flow recovery and safe restart of crude oil pipelines. Up to
now, the thixotropic models for waxy crude have been all viscoplastic models, without considering the
viscoelastic part before the yield point. In this work, based on analyzing the variation of the elastic stress
and viscous stress in the Mujumbar model, a new viscoelasto-plastic model is proposed, whose shear
stress is separated into an elastic component and a viscous component. The elastic stress is the product
of the shear modulus and elastic strain; the shear modulus is proportional to the structural parameter. For
the elastic strain, we followed the line of Zhu and his coauthors and assumed that it may be expressed
by an algebraic equation. The model is validated by stepwise shear rate tests and hysteresis loop tests on
Daqing and Zhongyuan waxy crude. The results show that the model’s fitting and predictive capability is
satisfactory.
關(guān)鍵詞
-
Thixotropy, viscoelasticity, viscoelasto-plastic model, thixotropic model, waxy crude