As oil and gas production gradually shifts to deep and ultra-deep formations, the pressure and complexity of stratum is increased and drilling efficiency is decreased. Based on this, a Dual-diameter and bi-speed composite drilling method that can realize the different depth, diameter, and rotate speed coupling using only hole-bottom power is proposed in this paper. And a Dual-diameter and bi-speed composite drilling tool is designed, processed, and carried out to complete the field experiment. The tool is connected by a two-stage screw to make the rotate speed of a pilot bit higher than that of the reaming bit to increase the rate of penetration. And a concave bottom hole is formed so that the ground stress is released and the drillability of rock is lifted. Based on the introduction of the speed-up mechanism of the tool, the numerical analysis of the drilling performance of the tool with different diameter ratios and rotate-velocity combinations is completed. The experimental data showed that the Dual-diameter and bi-speed composite drilling method can obviously increase the rate of penetration and drilling efficiency, and also help to reduce the risk of stick-slip and prolong the service life of the drill bit.

随着油气生产逐渐转移到深层和超深层，地层的压力和复杂性增加，钻井效率降低。在此基础上，提出了一种仅用孔底功率即可实现不同深度，直径和转速耦合的双径双速复合钻进方法。设计并加工了双直径双速复合钻具，完成了现场试验。该工具通过两级螺钉连接，以使导向钻头的转速高于铰孔钻头的转速，从而提高钻速。并且形成凹形的底部孔，从而释放地应力并提高岩石的可钻性。基于该工具加速机制的介绍，对不同直径比和转速组合的刀具的钻削性能进行了数值分析。实验数据表明，双径双速复合钻进方法可以明显提高钻速和钻进效率，也有助于降低粘滑风险，延长钻头的使用寿命。