建筑工程、工业与民用水井和给排水等部门要求钻井直径较大。大口径反循环钻进,由于液流上返速度高,利于携带岩屑,减少岩屑在孔内的重复破碎,且能大量地排出完整的砂砾卵石,它比正循环钻进效率高,且成井质量好,钻头寿命长,消耗材料少,成本低。所以,它在上述工程钻探中应用较广。 Construction, industrial and civil wells and water supply and drainage departments require drilling larger diameter. Large-caliber reverse circulation drilling, due to the high rate of liquid back up, is conducive to carry debris, reducing debris in the hole repeated crushing, and can discharge a large number of complete gravel, it is more efficient than the positive cycle, and Well into the well, bit long life, less material consumption, low cost. Therefore, it is widely used in the above engineering drilling.