摘要
使用控制应力流变仪 ,在原油凝点附近温度区域对大庆原油和胜利原油进行了线性粘弹性应力范围内的小振幅振荡剪切实验。以原油开始出现线性粘弹性应力区间的最高温度作为基准温度定义了相对温度 ,对粘弹性参数进行了分析对比。研究表明 ,大庆原油及胜利原油在各自凝点以上 4℃时 ,均表现出明显的粘弹性特征 ,其损耗角分别为 37.6 6°和 76 .5 5°。在相同的相对温度下 ,大庆原油的弹性特征明显好于胜利原油 ,大庆原油的粘弹性参数对温度的敏感性也明显好于胜利原油。两种原油粘弹性不同的主要原因是其胶质、沥青质含量和析蜡特性不同。凝点温度附近的原油流变性及其随温度的变化规律应该作为确定输油管道进站温度的重要依据 ,目前 ,仅以原油凝点作为确定进站温度的主要依据是不合理的。
Small amplitude oscillatory shear tests on Daqing and Shengli crude oils were conducted at the temperature range near the gel points of oils by using a stress controlled rheometer. The relative temperature was defined, taking the highest temperature as the reference temperature, at which crude begins to show linear viscoelasticity. The relative temperature was employed for comparing temperature dependence of the linear viscoelastic properties between the two kinds of oils. Both waxy crude oils were found to have obvious viscoelastic characteristics at a temperature 4 ℃ above their gel points. The loss angles are 37.66°and 76.55° for Daqing crude and Shengli crude respectively. At the same relative temperature, Daqing crude showed more distinctive elastic characters than Shengli crude. Additionally, the viscoelastic parameters of Daqing crude were more sensitive to temperature than those of Shengli crude. The different contents of resin and asphaltene and characteristics of wax crystallization were responsible for the difference of viscoelstic characteristics between the two kinds of crude oils. It was revealed that the strength of wax crystal structure and its variation with temperature were quite different for different oils at a temperature near the crude gel point. Therefore it is important that rheological properties and the temperature dependence of crude in the critical temperature range near the gel point should be taken into serious consideration in determination of the lowest operation temperature in a hot oil pipeline. The current practice only using the gel point or pour point as the sole basis is improper.
出处
《石油大学学报（自然科学版）》
CSCD
北大核心
2003年第2期90-92,共3页
Journal of the University of Petroleum,China(Edition of Natural Science)
基金
中国石油天然气股份有限公司资助项目 (0 2 0 2 0 1 0 1 0 2 )
