摘要
作者研制了一种用于钻孔径75mm,岩心直径35mm的钻具,使用该钻具钻进时,无需升起钻杆即可收取岩心和检查或更换钻头.
A special drilling device is developed for drilling wells of 75 mm bore diameter and 35mm core barrel diameter. On drilling with this tool, the drill core can be retrieAved and the bit examined and changed without lifting the drill pipe.
