扭转冲击钻具设计与室内试验

The design and laboratory test of torsional percussion tool

常规钻具在钻硬地层时机械钻速低,钻头失效快,钻井成本高。为此,设计了扭转冲击钻具。该钻具可将流体的液压能转换成扭向的、高频的机械能并直接传递给PDC钻头,给钻头施加周期性的低幅高频扭转冲击,当与钻柱稳态扭矩相结合时,能对钻头施加高效的破岩扭矩,大幅减小或消除钻头的粘滑振动,在保证井身质量的同时提高机械钻速,延长钻头寿命。对扭转冲击钻具的关键部件——扭转冲击副的运动可行性分别进行了仿真分析和室内试验。结果表明,扭转冲击副运转顺利,滑动块与传动轴周期性的碰撞可对传动轴施加周期性的低幅高频扭向冲击。

Conventional drilling tools are characterized by low penetration rate,early drill bit's failure and high drilling costs in drilling hard formations.Therefore,the torsional percussion tool was designed.The tool could convert the hydraulic energy of fluid into torsional and high-frequency mechanical energy and transmit it directly to the PDC drill bit and give it a cyclic low-amplitude high-frequency torsional impact.When it was combined with the drillpipe's steady torque,it could impose on the drill bit a high-efficiency rock-breaking torque,greatly reducing or eliminating the bit's stick-slip vibration.It could improve the penetration rate and lengthen the bit's service life and at the same time ensure the quality of the well.A simulation analysis and laboratory test of the torsional impact pair which was the key part of the torsional percussion tool was conducted to deal with its motion feasibility.The result showed that the pair ran smoothly and the cyclic collision between the sliding block and the transmission shaft could give the transmission shaft a cyclic low-amplitude high-frequency torsional impact.