油田注汽管道内盐沉积的特性

摘要

针对油田污水回用于热采锅炉导致注汽管道内壁盐沉积的问题,选取新疆油田某区注汽管道内积盐为试样,采用SEM,XRD,EDS,XPS等手段对积盐进行表征.探讨了注汽管道内积盐成因,并提出了防止和缓解积盐的措施.表征结果显示,注汽管道内壁附有的积盐呈规则块状,剖面平滑致密,外表面粗糙,可见大量针状物,主要组成为Na2Si2O5和少量Na2CO3.实验结果表明,注汽锅炉给水中高浓度的NaCl不会沉积在管道内壁,积盐是进水中硅酸、碳酸氢钠、碳酸钠在高温、高压(12.6 MPa,486℃)条件下长时间作用形成的.增强蒸汽管道的保温措施,并控制回用污水中的硅含量可有效缓解注汽管道内盐沉积形成.%When oilfield sewage was reused in thermal recovery boiler,salt deposition formed in steam pipeline in the Xinjiang oilfi eld. The salt deposition was characterized by means of SEM, XRD,EDS and XPS. The results showed that the salt deposition in steam pipeline was regular block shape with smooth dense section and rough surface,and its major components were Na2Si2O5and a small amount of Na2CO3,which formed due to the interaction of silicic acid,sodium bicarbonate and sodium carbonate in reused sewage under high temperature and high pressure(12.6 MPa and 486℃), and high concentration sodium chloride in the reused sewage would not deposit in the pipeline. The formation of the salt deposition could be relieved through improving the heat preservation of the steam pipeline and controlling the silicon content in the reused sewage.