深井固井变排量减轻U型管效应理论研究

Research of Variable Displacement Alleviates for "U" Type Tube in Deep Well Cementing

深井固井过程中U型管效应的存在,使得流体的返出排量不等于注入排量,特别是当水泥浆返出套管鞋一定体积后,环空返速显著降低,从而严重影响了顶替效率。为了减轻U型管效应的影响,提出了一套变排量顶替技术设计方案,通过与固定排量顶替时相比,真空段存在时间缩短13.8%,U型管效应期间的最低环空返速提高15.73%,整体顶替效率提高了5%左右,从而为深井注水泥设计提供了参考依据。

The ＂U＂ type tube＇s existence in deep well cementing.Liquid＇s returning displacement is not equal to injection displacement.Especially,when a certainty of grout comes out of the casing shoes,annulus velocity reduces remarkablely,so the replace efficiency is seriously affected.In order to alleviate ＂U＂ type tube＇s influence,a suir of variable displacement replacement technology designing program is brought up.Compared to the fixed displacement replacement,the existence time of vacuum segment is shorten 13.8%,the lowest annulus velocity during ＂U＂ type tube is improved 15.73%,the overall efficiency of the replacement is improved about 5%,which could provide reference for cementing design in deep well.