W/O型含蜡原油乳状液触变特性
The thixotropic behavior of W/O waxy crude oil emulsion
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摘要: 海上油田多产高含蜡原油, W/O型含蜡原油乳状液是油水混输管道输送介质的一种常见存在状态, 其触变性是管道停输再启动计算和可泵性评价的重要基础资料。滞回环是物料触变特性表征方法之一, 通过应力线性增加又线性减小形成滞回环的加载模式研究了W/O型含蜡原油乳状液凝点温度附近胶凝状态的触变特性。结果表明: W/O型含蜡原油乳状液胶凝体系触变性的强弱不依赖于加载条件, 随着含水率的增加, 滞回环面积减小, 原油乳状液触变特性减弱, 表征结构恢复的滞回环面积比减小, 胶凝体系结构恢复程度变小, 这是由于分散相液滴的存在, 阻碍了蜡晶空间网状结构的恢复。Abstract: The products of offshore oil fields are mostly crude oil of high wax content. W/O waxy crude oil emulsion is a common existence state of the medium in oil-water mixed transmission pipelines, and its thixotropy is the important basic data for the shutdown and restart calculation and pumpability assessment of pipelines. Hysteresis loop is one of the methods to characterize the thixotropic behavior of materials. In this paper, the thixotropic behavior of gelled W/O crude oil emulsion near the condensation point temperature was investigated in the loading mode of increasing and then decreasing the stress linearly to form the hysteresis loop. It is indicated that the thixotropy of W/O waxy crude oil emulsion gel is not dependent on the loading conditions. With the increase of water content, the area of hysteresis loop and the hysteresis loop area ratio which reflects the structural recovery decrease, the thixotropic behavior weakens and the recovery degree of gelled system diminishes, for the presence of dispersed phase droplets hinders the recovery of wax crystal network structure.