提高复杂地层钻进效率的重要途径：谈钻孔采用优质泥浆护壁通过砂卵石层

On increase the efficiency of drilling in complex strata

试验证明，在结构松散、地下水位较高、粒径不均的深厚砂卵石地层中钻孔，采用膨润土与ＳＭ植物胶为主要材料的优质泥浆护壁，在效地解决了塌孔、漏浆等问题，同时还提高了钻进速度２～４倍，是一种十分有效和值得大力推广的砂卵石地层钻孔方法。

It is shown by experiments that when drilling on the loose structured strata with grad-ed sandy gravel and higher groudnwater table, the material for protect the wall of drilling holeshould use the one mainly consisted of bentonite and SM plant gum. The technology solves theproblems of the wall collapsing and seepage of slurry mud, at the same time the efficiency ofdrilling increase 2 to 4 times compared with the old one, thus it is a effective method and worthto spread in complex strata with sandy gravel.