冲击回转挤压成孔方法及凸轮型挤压钻头

在冲击回转挤压成孔的钻进中通常采用圆锥型的挤压钻头，这种钻头在松软地层中的钻进效率很高，但在高围压下的中、硬塑性地导中的钻进效率明显降低。针对这一问题，分析了地层因素对钻进效率的影响及其原因，针对圆锥型挤压钻头存在的问题，设计了凸轮型挤压钻头。并指出了冲击回转挤压成孔钻进方法的适用范围。

Percussion-rotary-extrudingDrilling Method and the Cam Extruding Bit

The conic extruding bit usually be put into use when adopting percussionrotaryextruding drilling method to drill. This bit has very higher drilling efficiency than others in loose soil. But it''s drilling efficiency would lower obviously in the middle and stiff plastic soil. To counter this problem, the writers analyzed the factors of soil that would effect drilling efficiency and the effecting reason. The shortcoming of the PRE bit have been find, and the cam PRE bit has been designed. The use range of the PRE drilling method be bind in this paper.