在泥岩和泥质砂岩地层钻进时,由于岩层遇水膨胀,质软而有粘性,因此在采取岩心时投入卡料不易到底,而且也卡不住岩心,常造成岩心脱落事故.使用双动双管虽可解决一定问题,但回次进尺短,效率也低,投球式钻具效率质量虽比较理想,但卸钻杆时泥浆喷溅严重,影响孔口操作,而 When drilling in mudstone and shaly sand formations, because the rock is watery, soft and sticky, it is not easy to put the material into the core when it is drilled in the mudstone, and it can not hold the core and often causes the core to fall off. Although double pipe can solve some problems, but the short footage back to the short, the efficiency is low, although the efficiency of the quality of the pitching drill is ideal, but when the drill pipe unloading serious mud splash, affecting the orifice operation, and