含蜡原油低温粘弹性研究的现状与分析

我国盛产含蜡原油,在低温(凝点温度附近)条件下,含蜡原油具有一定的粘弹性。概述了国内外含蜡原油低温粘弹性研究的主要进展。含蜡原油粘弹性起因于其内部形成的蜡晶结构。振荡剪切实验方法最适合于含蜡原油的粘弹性测量。粘弹性与胶凝温度、胶凝强度、屈服应力和触变性等参数有关。含蜡原油经历的热历史、剪切历史以及析蜡特性是影响粘弹性的主要因素。分析了在含蜡原油低温粘弹性认识上和研究中存在的问题。建议进一步研究含蜡原油粘弹性与屈服应力、触变性的关系,在机理研究方面加大力度;通过研究粘弹性与热历史、剪切历史的关系,建立管道运行和停输期间含蜡原油胶凝特性的预测模型,以更加有效地指导管道的安全运行。

Status and analysis of low temperature viscoelasticity of waxy crude oil

Waxy crude oil has the property of viscoelasticity at low temperature (near the gel point). The main research advances on low temperature viscoelasticity of waxy crude oil were summarized. Viscoelasticity of waxy crude oil originated from the structure of waxy crystal. The oscillation shear method is the most suitable for the viscoelasticity measurement of waxy crude oil. Viscoelasticity is related to some properties such as gel point, gel strength,yield stress and thixotropy. The main factors influencing the viscoelasticity are the thermal, shear history of waxy crude oil and wax precipitation characteristics. The existing problems were analyzed from two aspects of cogitation and research. The relations between viscoelsticity and yield stress, thixotropy need to be studied for the theoretical breakthrough. From the point of pipelining safety, the prediction model of gel status represented by viscoelastic parameters should be developed during the pipeline operation and shutdown.