本文介绍的采用套管钻进和潜孔锤钻进相结合的复合性钻进工艺，有效地解决了在卵砾石层中钻进的难题。
Difficulties are encountered in drilling in boulder formation are efficiently eliminated by using of a combined drilling technique which combines casing drilling with DTH drilling method.
采用组合钻具进行跟管钻进，通过随钻跟入的套管保护孔壁，解决因钻孔垮塌导致钻探效率和岩心采取率低等技术难题。
The problems of low drilling efficiency and low core recovery due to borehole collapse were solved with pulling in casing while drilling through using combined BHA with casing.
本方法与书本上所述的套管护壁跟管钻进方法有反向思维操作概念。
This is a reversal thinking operation concept against the pipe drilling method of casing pipe wall protection described in conventional books.
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