三种卵砾石地层钻进用钻头的野外试验对比研究

针对卵砾石地层的钻进实践，先后设计与试验了三种类型的钻头；普通八角合金钻头、金刚石-硬质合金复合球齿钻头与孕镶金刚石-针状合金复合式钻头。本文在简要介绍三种钻头各自结构特点与设计原理的基础上，对三种类型钻头进行了对比试验，结果表明，金刚石-硬质合金复合球齿钻头与孕镶金刚石-针状合金复合式钻头比普通合金钻头寿命高5倍以上，单位成本（元／m）下降50％，取得了明显的效果，研究成果得到了推广应用。

Comparison of field experimental research on three types of bits for drilling gravel and cobble stratum

In order to solve the existing problems of drilling gravel and cobble stratum,common tungsten carbide-insert drill bits,composite diamond-tungsten carbide button bits and impregnated diamond-tungsten carbide bar bits were designed and tested successively.At the base of briefly introducing principles and structural features of three types drill bits,comparison experiments have been conducted.The test results indicate that the lifespan of composite diamond-tungsten carbide button bits and impregnated diamond-tungsten carbide bar bits are more 5 times than that of common carbide-insert drill bits,their drilling cost per meter has been decreased by 50%.So the former two drill bits have been promoted in the drilling gravel and cobble stratum due to their good drilling effect.