剪切作用对含蜡原油黏弹性的影响规律

为了探索剪切作用对含蜡原油流变性的影响规律,使用高精度的控制应力流变仪测量经历相同降温和不同剪切作用的大庆原油黏弹性参数(储能模量和耗能模量)).用黏性流动能量耗散表示剪切作用.得到了黏弹性参数随剪切作用的变化规律,建立了相应的关系式.观察原油的黏弹性参数随剪切作用和恒温静置时间的变化,发现从黏弹性随恒温静置时间变化的稳定阶段来看,原油在动态降温和静态降温下的黏弹性存在一定差别,不能简单地将静态降温条件下测得的流变数据用于输油管道工艺计算;而剪切作用的变化对原油流变性的影响较小,这对于评价含蜡原油在管道运行和停输期间的流变性具有一定指导意义.

Effect law of shear on the visco-elasticity of waxy crude

In order to investigate the effect of shear on rheological property of waxy crude,the viscoelastic parameters(energy storage modulus and energy consumption modulus) of Daqing crude oil which undergoes different shear actions and the same cooling history are measured using a stress-controlled rheometer with high precision.The shear action is characterized by viscous flowing energy dissipation.The variation laws of the viscoelastic parameters with shear action are obtained,and the corresponding relational equations are established.The variation laws of the viscoelastic parameters with shear action and holding time are observed.It is found that in the stable varying stage of the viscoelastic parameters with holding time,there is a difference of the viscoelastic parameters between in dynamic and static cooling,so the data of the viscoelastic parameters measured under static cooling cannot be used for the technological calculation of oil transportation pipeline;the change of shear action has a little influence on the rheological property of the waxy crude,and this discovery can be used as a guidance for the assessment of the rheological property of waxy crude during the periods of pipeline operation and shut-down.