水敏性软硬交错地层瓦斯抽放孔PDC钻头的设计与应用

Design and Application of PDC Drill Bit for Gas Drainage Drilling in Hard and Soft Water Sensitive Multi-interbedded Formation

摘要:

贵州地区煤炭资源中瓦斯突出灾害非常严重，矿下掘进前的瓦斯抽放工程量巨大。在瓦斯抽放孔钻进施工过程中，由于现场操作的不熟练和使用钻头的盲目性，使用的钻头数量不仅非常大，而且效果较一般。针对当地复杂地层，对钻头进行了改进设计，取得了良好的效果。钻头寿命由原来的166.5 m提升至399 m，钻进效率由8 m/h提高到12.4 m/h左右。

关键词:水敏性地层;软硬交错地层;PDC钻头;瓦斯抽放孔

Abstract:

Because of the serious gas outburst disasters in coal resources of Guizhou area, the gas drainage quantity is very large before mining. In the drainage process, due to the unskilled operation and the blind choice of the bits, a lot of bits were used without good effects. According to the special geological conditions, the improvement was made on the drill bits and good results were obtained. The service life of the drill bit is prolonged from 166.5 m to 399 m and the drilling efficiency is increased from 8 m/h to about 12.4 m/h.

Key words:water sensitive formation; multi-interbedded formation; PDC bit; gas drainage hole