窄密度窗口精细控压钻井重浆帽优化技术  

Optimization of Heavy Mud Cap in Narrow Density Window Precise Managed Pressure Drilling

作　　者：彭明佳 周英操 郭庆丰 王天博[2] 康健 

机构地区：[1]中国石油钻井工程技术研究院,北京102206 [2]中国石油塔里木油田分公司,新疆库尔勒841000

出　　处：《石油钻探技术》2015年第6期24-28,共5页Petroleum Drilling Techniques

基　　金：国家科技重大专项"窄密度窗口安全钻井技术与配套装备"(编号:2011ZX05021-003);中国石油天然气集团公司重大专项"深层碳酸盐岩地层与井筒耦合作用机理与压力自动控制方法研究"(编号:51274221)资助

摘　　要：在我国西部深层碳酸盐地层控压钻井中,常采用简易重浆帽作业方式,但作业过程中存在引起井底压力较大波动乃至诱发井下故障的风险。针对该问题,通过分析重浆注替期间不同阶段重浆分布的实时变化,改进了井筒压力控制方法,优化了重浆帽设计工艺：将压水眼重浆和重浆帽进行优化组合,以压水眼重浆返出井口为压力控制节点,分5段进行压力控制设计,压力控制区间为0-5 MPa,并以此调整井口实时压力控制策略,实现井筒压力波动幅度小于±0.35 MPa。塔中地区13口井的应用显示,起下钻中重浆的使用量平均减少21.5%,注替作业时间平均缩短17.7%。现场应用表明,该技术在精细控压钻井注替重浆帽过程中能更加有效地控制井筒压力波动,对精确控制井筒压力剖面、降低井控风险具有较好的应用效果。When managed pressure drilling was conducted in the deep carbonates in western China,a simple heavy mud cap mode was generally used,but it resulted in larger fluctuation of bottom hole pressure（BHP）and even precipitated the risk of downhole failures.In this paper,therefore,the borehole pressure control method was improved and a heavy mud cap design was optimized after analysis was conducted on the real-time variation of heavy mud distribution at each stage of heavy mud injection.Nozzle killing heavy mud and heavy mud cap（two drilling fluids with different densities）were optimized and combined.A pressure control design was carried out in five stages with the returning of nozzle killing heavy mud to the well head as a pressure control node,and pressure control ranged from zero to 5 MPa,and based on that,real-time wellhead pressure control strategies were adjusted in order to ensure the fluctuation range of the wellbore pressure to less than ±0.35 MPa.When the method was applied to 13 wells in central Tarim,heavy mud consumption during the trip was reduced by 21.5% and injection time was shortened by 17.7%.It was shown that the new method could keep the BHP steady more efficiently and achieve better effects of precise wellhore pressure profile control and well control risk reduction when it was applied to the injection of a heavy mud cap in precise managed pressure drilling regime.

关 键 词：窄密度窗口 精细控压钻井 重浆帽 优化设计 

分 类 号：TE249[石油与天然气工程—油气井工程]