W/O型含蜡原油乳状液胶凝体系的屈服特性

Yield Characteristics of the Waxy Crude Water-in-Oil Emulsions Cementitious System

在恒定剪切应力和剪切应力线性增加2种加载模式下,研究了油包水(W/O)型含蜡原油乳状液胶凝体系在凝点温度附近的屈服行为。以原油乳状液胶凝体系的屈服应变、屈服剪切速率为特征量,分析了剪切应力加载条件、加载量和胶凝体系含水率对含蜡原油乳状液胶凝体系屈服特性的影响规律。引用屈服应变比例系数的概念,分析了不同恒温静置时间后含蜡原油乳状液胶凝体系结构恢复程度及其影响因素。研究发现:屈服应变可作为W/O型含蜡原油乳状液胶凝体系屈服的判据;增大原油乳状液胶凝体系含水体积分数,屈服应变增大,屈服剪切速率减小,体系恢复度增加。增大剪切应力加载量或剪切应力增加速率,原油乳状液胶凝体系屈服剪切速率增大,该体系的结构恢复程度变差。

The yield behavior of water-in-oil(W/O)waxy crude oil emulsion cementitious system was studied experimentally under two loading modes of constant and linear increase shear stress.Based on the yield strain and shear rate of the crude oil emulsion cementitious system,the effects of shear stress loading conditions,loading amount and water contents on the yield characteristics of waxy crude oil emulsion cementitious system were analyzed.The concept of yield strain proportional coefficient was introduced to analyze the structural recovery degree and its influencing factors of waxy crude oil emulsion cementitious system after different constant temperatures and static time.It is found that the yield strain can be used as the yield criterion of W/O waxy crude oil emulsion cementitious system.With the increase of water volume fraction of the crude oil emulsion cementitious system,the yield strain increases,the yield shear rate decreases and the recovery degree increases.With the increase of shear stress loading or shear stress increasing rate,the yield shear rate of the crude oil emulsion cementitious system increases,and the structural recovery of the system becomes worse.