To improve the rate of penetration, reduce drilling cost and make comprehensive use of the strengths of pulsed jet and super-high pressure jet drilling in deep wells and super-deep wells, the pulse-type downhole boosting drilling device was designed. The structure and operating principle of the device were introduced. The targeted design of key parameters was carried out according to different drilling conditions. According to the study the acting force of high pressure piston was determined as 35% of WOB. The diameter of high pressure piston was taken as 30 mm in PDC bit drilling and 35 mm in roller bit drilling. The piston stroke was determined according to the downhole vibration displacement of drilling bit, with its value being 25 mm. The frequencies of piston stroke were 4 Hz and 6 Hz. Finally the high pressure fluid displacement was obtained through calculation. The effect of the internal and external pressure difference of the device is on the end face of the transmission shaft and thus it has a hydraulic boosting effect. Therefore, the hydraulic acting force was calculated in light of drilling conditions with different bits.%为了提高深井超深井的机械钻速,降低钻井成本,综合利用脉冲射流和超高压射流钻井的优点,设计了脉冲式井下增压钻井装置.介绍了其结构和工作原理,根据不同钻井状况有针对性地设计关键参数.根据研究,确定高压活塞作用力取为钻压的35％,PDC钻头钻井时高压活塞直径取30 mm,牙轮钻头钻井时高压活塞直径取35 mm,活塞行程根据钻头在井下振动的位移确定,取为25 mm,活塞频率为4和6 Hz,计算得到高压流体排量.由于脉冲式井下增压钻井装置内、外压差作用在传动轴上端面,具有水力加压作用,所以针对不同钻头钻井情况,进行水力加压作用力计算.
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