随钻扩眼钻柱结构优选及现场应用效果评价

Reaming While Drilling Drillstring Structure Optimization and Application Performance Evaluation

在随钻扩眼作业过程中,扩眼工具组合是最重要的可控参数,不合理的钻柱结构会使钻柱振动加剧.鉴于此,基于有限元动力学分析方法,建立钻具-地层有限元动力学分析模型,模拟不同扩眼工具和钻柱结构对钻具运动轨迹、扭转角速度及钻杆等效应力的影响.研究结果表明：随着2段承压钻杆间普通钻杆长度的增加,下部钻具组合在高低边方向的运动加剧,承压钻杆长度增加,下部钻具振动减小;近钻头钻杆长度和位置对承压钻杆钻柱所受的等效应力和扭转角速度影响不大,但会改变加重钻杆的位置,使井口轴向力有很大变化.推荐目标区块0149.2 mm侧钻井眼内随钻扩眼工具组合为：双中心钻头＋0120. 0 mm单弯螺杆＋088. 9 mm无磁承压钻杆 1 -2 根＋088. 9 mm钻杆10-20根＋088. 9 mm加重钻杆1 5根＋088. 9 mm钻杆.所得结论可为解决小井眼随钻扩眼作业中稳定性差以及扭矩突变所引起的钻柱破坏提供参考.

The reaming tool BHA is the most important controllable factor during reaming while drilling operations ,whereas the irrational drill string structure could lead to intensified drill string vibration. In view of this, the drill string - formation finite element dynamics model has been established based on finite element dynamic analysis methods, to simulate the effects of different reaming tools and drill string structures on the drilling tool trajectory, torsional angular velocity and drill pipe equivalent stress. The simulation results show that, with the increase of drill pipe between the two segments of HWDP,BHA movement in the direction of the high and low side is intensified. The increased length of the HWDP will reduce the BHA vibration. The near-bit drill pipe length and position have little impact on the equivalent stress and torsional angular velocity of HWDP, but will change the HWDP position and consequently greatly change the wellhead axial force. The recommended reaming while drilling BHA for sidetrack in 0149. 2 mm borehole in target block is bicenter drill bit ＋ 0120. 0 mm single-bend screw rod＋1 ？2 088. 9 mm non-magnetic drill rod＋10-20 088. 9 mm drill pipe＋15 088. 9 mm HWDP＋088. 9 mm drill pipe.