阀式连续循环钻井技术在番禺油田大位移井的应用

Application of valve-type continuous circulation drilling technology to the extended reach wells in Panyu Oilfield

针对番禺10-8油田大位移井?215.9 mm井段钻井液安全密度窗口窄(最小1.30~1.70 g/cm^3)、需穿越断层,且上部?311.2 mm稳斜井段长(3 508 m)、井斜角大(最大达到80°)、岩屑易堆积等问题,引入阀式连续循环钻井技术,结合实例分析了该技术的现场应用效果,总结了出现的问题及改进措施。通过分析番禺10-8油田PY10-8-A3井?215.9 mm井段的钻井技术难点,阐述了引入连续循环钻井技术的必要性,介绍了该技术的工作原理和主要设备,分析了该钻井技术的作业特点及应用效果。结果表明:全井段钻井液循环当量密度(ECD)变化率小于7.6%,井内循环压力稳定,平均机械钻速高达21.7 m/h,井眼清洗效果良好,安全平稳钻过断层,未发生任何漏垮卡等复杂情况。

In Panyu10-8Oilfield,the hole section of?215.9mm in an extended reach well has to run through faults and its safety density window of drilling fluid is narrow(minimum1.30~1.70g/cm3).Besides,its angle holding section of?311.2mm in the upper part is long(3508m)with high deviation angle(maximum80°),and cutting tends to accumulate easily.The valve-type continuous circulation drilling technology was introduced in this paper.Its filed application results were analyzed based on case study,and the problems and improvement measures were summarized.The necessity to introduce the valve-type continuous circulation drilling technology was illustrated by analyzing the technological difficulties which were encountered during the drilling of?215.9mm hole section of Well PY10-8-A3in Panyu10-8Oilfield.Then,the working principles and main equipments involved in this technology were introduced,and its operational characteristics and application effects were analyzed.It is indicated that the variance ratio of drilling fluid ECD(Equivalent circulation density)in the whole well is less than7.6%,borehole circulation pressure is stable and average ROP is up to21.7m/h.Furthermore,borehole is well cleaned and faults are drilled through safely and smoothly without any leak,collapse or sticking.