水力旋冲钻井工具破岩影响因素模拟及应用

常规的冲击钻井工具不能满足井眼轨迹控制要求、使用寿命有限、缓解脱压不显著等问题,影响了在定向井钻井中的推广应用。建立φ215.9 mm PDC钻头和岩石的有限元模型,分析钻井参数对破岩效率的影响规律,结果表明:冲击频率为17.5 Hz和35 Hz时,破岩效率最优;破岩效率随钻压增大而增加,而后变化逐渐平缓;破岩效率随钻头转速增大而增加;破岩效率随冲击载荷的增加变化平缓。据此研制了新型水力旋冲钻井工具。现场试验表明,该工具符合定向水平井“一趟钻”工艺要求,使机械钻速提高56%,使用寿命达150 h,MWD信号正常。

Rock Breaking Simulation and Experiment Research of Hydraulic Rotary Drilling Tool

Hard rock and friction are the critical factors having effect on directional well drilling speed. Normal impacting motor cannot meet with guidance requirement of well trajectory, which service life is short and cannot decrease friction. Shengli petroleum company developed hydraulic rotary drilling tool, increased drilling speedby hydraulic hammer, and met with drilling technology of direction well. Simulation research results show:(1)rock breaking efficiency is faster when impacting frequency is 17.5 Hz and 35 Hz,(2)Rock breaking efficiency increases with increasing weight-on-bit, and then changes gradually,(3)The rock breaking efficiency increases with the increase of the bit speed,(4)The rock breaking efficiency changes gently with the increase of the impact load. Based on this, a new type of hydraulic rotary drilling tool was developed. The experiment result of drilling two wells shows that, the new hydraulic rotary drilling tool meet with one trip drilling of directional well perfectly, the mechanical drilling speed increases by 56%, the service life can reach 150 hours and the MWD signal is normal.