深斜井永久式封隔器两种套铣方式风险分析与优化措施

在深斜井大修作业中,为了适应海上修井机作业能力的需要,需要处理井下永久式封隔器。采用磨铣方式处理难度大、周期长、费用高,因此通常采取套铣方式,仅将可钻式永久性封隔器卡瓦及密封套铣掉,再打捞回收或下推至人工井底,直至不妨碍下一步作业。从作业井实际情况出发,针对深斜井永久式封隔器,采用了两种不同动力驱动方式进行套铣处理:一种是地面转盘驱动,井下全部钻具都处于旋转状态,全程摩阻及扭矩大,可以施加较大钻压;另一种为井下马达驱动,即只有马达以下钻具旋转,而马达以上钻具不转,从而降低摩阻,但施加钻压较小,否则容易引起马达失速,所以对马达性能要求较高。通过套铣风险对比分析,分别对两种套铣钻具与参数进行了优化,提出了套铣成功与否的判断依据,为现场应用提供了借鉴。

Risk analysis and measurements optimization for two casing milling modes of permanent packer in deep deviated well

Pemanent packer for underground treatment is needed or capability demand of marine workover rigs in overhaul operation of deep deviated well. Adopting grinding and milling mode has some disadvantages such as difficult treatment,long period and high cost. Therefore casing milling mode,which mills slips and seal sleeves of drillble permanent packer then has salvage and recovery or pushes down to artificial bottom hole untilnot influencing next oper-ation, is usually adored Target against permanent packer of deep deviated well, two different dynamic driving modes are adopted to have milling treatment from actual situation of operation well. One is ground ground rotary table drive,which may put big bit pressure because all drilling tools are in rotating state with whole friction and big torsion distance, the other is under:ground motor drive, that is, drilling tools rotates below motor but above motor to reduce friction However, bit pressure imposed is small or motor stall is easily a roused. Therefore the motor stall is easily aroused.Therefore, the motor performance requirement is higher.Criterion recognition if casing milling succeeds is put forward by risk comparative analysis on casing milling and optimization of two casing milling bit tools and parameters, which offers reference or field application.