含蜡原油触变性测试方法

现有触变性测试方法(加载方式)包括恒剪切率、剪切率阶跃、控制剪切率滞回环、剪应力阶跃以及控制剪应力滞回环等。利用这些方法对同一条件下含蜡原油的触变性进行测试,并利用Houska触变模型和双结构参数触变模型进行拟合。利用一种方法测试数据拟合出的触变参数对其他测试方法加载条件下的应力进行预测,依据预测结果与实测值的吻合程度,对测试方法进行评价。结果表明:无论采用何种测试方法,利用剪切率高的加载条件得到的实验数据拟合的触变参数,均可成功地对较低剪切率加载条件下的应力进行预测,反之则会出现结构参数为负值进而导致预测失败的情况;利用同一测试方法的多组实验数据共同拟合触变参数,可以提高对其他加载方式下应力的预测值与实测值的吻合程度。

Thixotropy test method of waxy crude oil

Existing thixotropy test methods(loading methods) include constant shear rate,shear rate stepping,control hysteresis loops of shear rates,shear stress stepping,and control hysteresis loops of shear stresses,etc..These methods are used to test the thixotropy of waxy crude oil under the same conditions,and Houska thixotropy model and double-structural parameter thixotropy models are used for fitting.Thixotropy parameters from fitting of test data by one method are used to predict the stress of other test methods under loading conditions.Based on the coincidence degree between prediction results and measured values,the test method is evaluated.Results show that no matter which test method is used,the thixotropy parameters from fitting of test data obtained by the use of loading conditions with high shear rates can all successfully predict stress under loading conditions with lower shear rates,otherwise the structural parameter is negative so as to cause prediction failure;the thixotropy parameters from common fitting of multiple group of test data by the same testing method can improve the coincidence degree between predicted values and measured values of stress under other loading methods.