大庆采油五厂注水系统地面管线结垢原因研究

THE CAUSE OF INORGANIC SCALE FORMATION IN SURFACE PIPELINES OF WATER INJECTION SYSTEM AT THE FIFTH DAQING OIL PRODUCTION FACTORY

大庆采油五厂注水系统地面管线出现结垢问题。在详细分析注水水质和垢样的基础上 ,对结垢原因进行了探讨。结果表明大庆采油五厂所有注水都有CaCO3 结垢倾向 ;使用的清水和回注污水是不相容的两种水 ,混合使用会产生较为严重的CaCO3 结垢。特别是当清水量在 30 %— 80 %之间时CaCO3 结垢倾向较大 ,这也正是大庆采油五厂注水系统地面管线出现严重结垢的原因。碳酸亚铁是两种水分注时管线中垢的主要成分 ,表明该注水系统中有腐蚀发生。

On the basis of systematic analysis of the injection water and scale substances for their composition and by using Stiff Davis's saturation index SI it is ascertained that① all the waters used for reservoir flooding at the 5th Daqing oil production factory tend to form CaCO 3 scale; ②the fresh water and the recycled produced water are incompatible and their mixture gives rise to serious CaCO 3 scaling at volume rato range 3∶7—8∶2, in particular, that causes severe scaling problems in surface injection pipelines. FeCO 3 is the main component of the scale substances taken from pipelines when the fresh and the recycled produced water are transported separately and this shows that corrosion occurs in the water injection systems.