Abstract: The flowability of waxy crude oil from South China Sea under low temperature can be improved with a chemical treating agent. The addition of 150 ppm EVA complex greatly improved the flowability: pour point was reduced from 32℃ to 11.5℃, apparent viscosity lowered by 86.9% and yield stress at 14℃ lowered by 98%. The feed temperature, cooling rate, and the composition and structure of the treating agent which would affect low temperature flowability were investigated. The mechanism of improvement is discussed in the light of wax composition, carbon number distribution of normal alkanes and their susceptibility to EVA of different structures. Cocrystallization is likely to take place only when the ethylene chain in EVA is nearly equal to the normal alkane chain in the crude oil. The crystal forms can then be modified, leading to pour point depression and viscosity reduction.

摘要： 本文研究了采用化学处理剂改善南海高含蜡原油的低温流动性,结果表明,添加150ppm EVA复合化学处理剂,原油低温流动性得到明显改善,凝固点由32℃降至11.5℃,表观粘度降低86.9%,1;℃时屈服值降低98%。同时考察了添加温度,冷却速度以及化学处理剂的化学组成和结构对改善原油低温流动性的影响。根据南海高含蜡原油中蜡的组成和正构烷烃的碳数分布及其对不同结构的EVA的感受性,讨论了化学处理剂改善原油低温流动性的机理,指出,EVA中乙烯链长与原油中正构烷烃链长相近时才能形成共晶,起到改变原油中蜡的结晶形态的作用,达到降凝减粘效果。