旋转模块式PDC钻头破岩机理研究

针对深部难钻地层钻头的钻速低、寿命短、能耗高等问题,在常规固定齿PDC钻头上引入旋转模块结构,旋转模块齿和固定切削齿“交叉刮切”破碎岩石,提高钻头的破岩效率,且旋转模块齿交替轮流工作的方式使得切削齿冷却及时,减缓切削齿的磨损,延长钻头寿命。介绍了新型钻头的结构特点和工作原理,对旋转模块进行了变参数实验,实验结果表明:旋转模块随着侧转角的增大,转速增加;随着轴倾角的增大,转速降低。研究得到旋转模块在不同结构参数下的切削载荷以及破碎比功的变化规律,验证了旋转模块齿和固定切削齿“交叉刮切”破碎岩石,能够降低破岩比功,为后续旋转模块式PDC钻头的设计提供理论依据和支撑。

Study on Rock-breaking Mechanism of Rotary Modular PDC Bit

Aiming at the problem of the low rate of penetration(ROP), high-energy consumption, short life of the bit in the deep formation, etc, a new structure of rotary module is introduced for the conventional fixed cutter PDC drill bit. The principle of alternate work of the rotating module teeth enables the cutters to be cooled in time, and making the wear on cutters to be balanced, thereby improving rock breaking efficiency, extending bit life. This paper briefly describes the structural characteristics and working principle of the new bit, and through the experimental study on the rotating module teeth, it can be concluded that with the increases of the side rake angle, the rotation speed of the rotary module increases, as the axial rake increases, the rotation speed decreases. The variation laws of the load and the breaking work ratio of the module under different structure parameters are obtained, and in the radial coverage area of the module, there exists "cross-scraping" of the rotating module teeth and the fixed cutters, and it has benefit to improve the rock breaking efficiency, which provides theoretical basis and support for the design of rotary modular PDC bit.