稠油采出水纳滤脱盐技术的适应性研究

Adaptability Study on the Nanofiltration Desalination Technology for Heavy Oil Produced Water

为评价SAGD高盐高硬高硅稠油采出水中纳滤膜在深度处理中的适应性,通过研究操作压力、操作时间、回收率等工艺参数对纳滤膜的影响规律,制定了纳滤膜的软化除硅与脱盐对策,实现SAGD采出水淡化后应用于注汽锅炉。研究结果表明,NF90膜对高盐高硬高硅采出水具有良好的适应性。操作压力为0.6 MPa时,NF90膜对Na^+及Cl^-的截留率为85%,对Mg^(2+)和SO_4^(2-)具有100%的截留率,对Ca^(2+)的截留率在90%以上,对SiO_2的截留率达85%;回收率达80%,且保持了稳定的产水通量,系统出水水质达到油田注汽锅炉进水水质指标。

In order to evaluate the adaptability of nanofiltration membranes in the deep treatment of the produced water with high salt, high hardness and high silicon, through studying the effect law of parameters such as operating pressure, operating time and recovery on nanofiltration membrane, the softening desilication and desalination countermeasures of nanofiltration are worked out, and the countermeasures are applied on steam injection boilers after SAGD desalination of produced water. The study results show that NF90 membrane has good adaptability to the produced water with high salt, high hardness and high silicon. While the operation pressure is 0.6 MPa,its rejection rate of Na^+ and Cl^- is 85%, 100% for Mg^2 + and SO4^2-, more than 90% for Ca^2 + and 85% for SiO2. Moreover, the water recovery rate can steadily reach to 80%, and the stable water production flux can be kept. The effluent water quality of the system meets the water quality requirement of the injection water for oilfield steam boilers.