我队以前在粘土岩、粉砂岩等软岩层进行取心钻进时,都是使用品字型钻头或螺旋肋骨钻头。实践表明,这两种钻头钻进软岩效率较低。为此,最近改用三翼高桩肋骨钻头。这种钻头的硬质合金按掏槽阶梯式排列,底出刃和内外出刃较大(见图)。钻进效率比上两种钻头高2—4倍(见下表)。这是因为钻头排粉良好,孔底清洁,切削具排列 My team used to use heart-shaped bits or helical rib bits for core drilling in soft rock formations such as clay rock and siltstone. Practice shows that these two kinds of drill bit lower soft rock drilling efficiency. To this end, the recent use of three-wing high-pile rib drill. This bit carbide cemented cut by notch arrangement, the end of the blade and the inside and outside the blade is larger (see photo). Drilling efficiency 2-4 times higher than the last two bits (see table below). This is because the drill row of powder is good, the bottom of the hole clean, cutting tools arranged