剪切历史对含蜡原油流变性的影响

利用DV3T流变仪通过控制剪切速率和小振幅振荡剪切的试验方法,分别研究了不同剪切历史对含蜡原油流变性的影响。结果表明:原油的表观黏度不仅受降温方式的影响,还与测量过程中选取的剪切速率有关;即使原油降温过程中所经受的剪切速率很小,其恒温静止达到平衡时的储能模量与静态降温的原油相比也有很大的差距;但随着剪切速率的增加,这种差距并不会有明显的变化;降温过程中剪切时间越长,原油的表观黏度越大;但恒温静止阶段的最终胶凝结构却越弱;此外原油在降温过程中存在着一个使其流变性恶化的最差高速剪切温度。

Influence of shear history on the rheological properties of waxy crude oil

The effect of different shear history on the rheological properties of waxy crude oil was investigated using DV3Trheometer. Both the small amplitude oscillatory shear test and the controlled shear rate test were employed in this study. The results show that the apparent viscosity of crude oil strongly depends on both the cooling methods and shear rates during test ; though just sheared with a small shear rate, the storage modulus of waxy crude oil in equilibrium state will be much smaller than the value of waxy crude oil after static cooling, but it leads no great change for the storage modulus with the increase of shear rate. The longer the shear time under the cooling process is ,the higher the apparent viscosity of crude oil is ,but the weaker the strength of the balance structure for waxy crude oil is. Otherwise there exists a worst high speed shear temperature for the rheological behavior of waxy crude oil..