中文摘要：

水力加压器通过节流作用将泥浆动力转化为轴向推力,可以减少因钻柱耦合振动及钻头与岩石互作用引起的钻压波动,从而给钻头施加较为恒定的钻压,延长钻头寿命,减少钻具疲劳失效,提高钻井效率。为了给中深井提供足够大的钻压及提高入井后的钻压调节能力,设计了适用于φ215.9 mm井眼的φ172 mm规格的五级双行程水力加压器。水力加压器工作时,通过主活塞杆和主缸体的花键副传递钻压和扭矩。花键副的载荷环境较为恶劣,应用有限元软件完成了压扭载荷作用下主活塞杆和主缸体的接触应力分析,得出主活塞杆和主缸体的静安全系数〉4,其结构安全性可以满足使用要求。

英文摘要：

Hydraulic thruster converts mud power into axial thrust through throttling action,it can reduce the WOB fluctuation because of the coupled vibration of drill string and the interaction between the drill bit and rock,thereby exerts a constant WOB,extends bit life,reduces drill stem＇s fatigue failure,improves the drilling efficiency.In order to provide sufficient WOB for medium-deep well and improve the post-adjustment ability into well,a 172 mm five-grade two-stroke hydraulic thruster for 215.9 mm borehole was designed.When it was at working,the hydraulic thruster transmitted WOB and torque through spline pair of master cylinder and piston rod.The load environment of spline pair was harsh,finite element software was applied to complete contact stress analysis of master piston rod and cylinder in pressure-torsion load.Analysis showed that the static safety factor of the master piston rod and master cylinder were greater than 4,the structure safety of design met the application requirements.