大直径定向长钻孔用PDC钻头设计与应用

Design and application of PDC bit for major diameter directional long drilling hole

针对煤矿井下中硬地层钻进中采用的常规单齿式PDC定向钻头和常规型扩孔钻头钻进寿命短,效率低,以及常规扩孔钻头在扩孔钻进中难以沿原孔轨迹钻进的缺陷,结合大直径定向长钻孔对三种钻头的需求,研制了两种新型PDC钻头,其中新型PDC定向钻头采用刮刀型平底结构并优化布齿,增加了切削齿数量,扩孔钻头采用圆弧形剖面,并沿切削剖面布齿,增大了切削自由面。针对两种钻头进行了现场应用,现场应用证明,新型PDC定向钻头受控性好,钻进稳定,在中硬地层钻进效率和寿命显著提高,是普通单齿式钻头的2倍,新型扩孔钻头能够沿先导孔轨迹扩孔钻进,钻头寿命是普通扩孔钻头的3倍以上。

Aiming at the short life and low efficiency of conventional single-tooth PDC directional drill bits and conventional reamer bits used in the drilling of medium-hard strata in coal mines,the difficulty for conventional reamer drill bits to drill along the original trajectory,as well as the demands for the three kinds of drill bits in the directional long drilling hole,two new PDC bits are developed. The PDC directional drill bit are designed with scraper flat structure,the cutting teeth arrangement is optimized,the reaming drill bit is of circular arc profile,and the cutting teeth is arranged along the bit profile,on-site application of the PDC bits is carried out. Field application shows that, the new PDC directional drill bit control is favorable with stable drilling performance. In the mid-hard ground,the drilling efficiency is significantly improved,and the bit life is 2 times of the ordinary single-tooth drill bit,the new reaming drill can be drilled through the pilot hole trajectory,drill life is more than 3 times of the normal reaming drill bit.