海上油田大位移井不间断循环系统实践及应用

Practice and application of uninterrupted circulation system for extended reach Well in offshore oil fields

世界范围内,一般把水垂比≥2且测深大于3000m的井或水平位移超过3000m的井称为大位移井;大位移钻完井技术,是当今国际钻井工程领域的高新技术,也是挑战旋转钻井极限的高难度前沿技术。随着水平位移和水垂比的不断增加,大位移钻完井面临着许多严重挑战,井眼清洁程度直接关系大斜度长裸眼的不稳定性与可安全延伸极限、水力循环的压耗控制、井下摩阻扭矩的严重性与控制能力、长套管串下入难度与磨损严重性及钻井设备能力的局限性与综合运用能力等,通过不间断连续循环系统现场应用与实践,大位移井钻井过程中全井段当量循环密度数值平稳,对海上大位移井保持稳定的当量循环密度(ECD)控制及安全作业有着很好的借鉴意义。

In the world,the well with water vertical ratio≥2 and sounding depth greater than 3000 meters or the well with horizontal displacement of more than 3000 meters is generally called extended reach well.Long reach drilling and completion technology is a high technology in thefield of international drilling engineering,and it is also a difficult frontier technology that challenges the limit of rotary drilling.With the increasing horizontal displacement and water-vertical ratio,long reach drilling and completion face many serious challenges.Borehole cleanliness is directly related to the instability and safe extension limit of large inclination and long open hole,pressure loss control of hydraulic circulation[1],the severity and control ability of downhole friction and torque,the difficulty and wear severity of long casing strings,and the limitation and comprehensive application ability of drilling equipment,etc.Through the field application and practice of uninterruptable continuous circulation system,The stable equivalent circulation density value of the whole well interval during the drilling of the extended reach well has a good reference value for maintaining stable equivalent circulation density control and safe operation of offshore extended reach well.