声速和衰减系数与含蜡原油特性的关系

Relationship between ultrasonic velocity and attenuation and the properties of waxy crude oil

当含蜡原油的温度低于蜡的析出温度后，蜡晶将不断析出并相互交联成网状结构；若网状结构达到一定强度，原油将失去流动而凝结。在该过程中不仅含蜡原油的流动特性发生变化，原油的声速和衰减系数也发生变化。本研究结果表明：含蜡原油的声速及衰减系数均随温度降低而增大；含蜡原油在凝结温度前后表现出不同的声速与温度的对应关系；含蜡原油在凝结后的声速与温度的关系同原油的含蜡量有关；含蜡原油的衰减系数在接近凝结温度时急剧上升。含蜡原油声速和衰减系数的变化对应于含蜡原油中有大量蜡晶析出与凝结的过程。

When the crystallization temperature having reached, the waxy crystals appear in the waxy oil. If the oil temperature Continue decreasing, the waxy crystals will be more and connect each other and the crystal structure will be formed. If the intensity of the crystal structure is strong enough, the oil will be jellied. It changes not only the flow properties of the oil, but also the velocity and the attenuation of ukrasonic wave transmitted in the oil. Results of measurement show that both ultrasonic velocity and attenuation increase while the oil temperature decreases. Beyond and under the oil jollification temperature, there are different relationships of ultrasonic velocity vs. temperature and it seems to be relative to the wax quantity in the oil. The ultrasonic attenuation increases sharply when the viscosity of the oil increases rapidly. These phenomena indicate that a lot of waxes have crystallized in waxy oil and the oil is jelling.