龙固井田巨厚表土层超大孔径深孔制冷孔施工技术研究

Study on construction technology of drilling super-large aperture deep cooling hole in super-thick topsoil in Longgu mine field

为解决龙固井田制冷钻孔穿过567m巨厚表土层、650mm超大孔径、840m大垂深、靶域半径≤1m的垂直度、管壁厚(重量达180t)的施工技术难题,采取在先导孔施工中增加一级450mm扩孔、加密到每30～50m测斜一次的科学施工技术措施,研究了泥浆配制比例,使泥浆粘度达到27S、密度1.16g/cm3的最佳配比,达到钻孔终孔最大偏距在0.645～0.993m的较高垂直度,套管安全顺利下放到位,注浆固管合格的要求,解决了巨厚表土层超大孔径钻孔施工的技术难题。

In order to solve the construction technical problems of drilling for refrigeration through 567m thick topsoil, super-large aperture of Ф650mm, large vertical depth of 840 m, the radius of target domain being not more than lm and thick tube wall （weighs up to 180t） in Long- gu mine field, some scientific construction technical measures are adopted that increasing a Ф450mm reaming in the construction of the pilot hole, densifying the inclination measurement- once every 30 - 50m; the slurry mixing ratio is researched to get the best ratio with viscosity of 27S and density of 1. 16g/cm^3. And then the maximum offset of the well completion reaches higher verticality within 0. 645-0. 993m; casing is run into position safely and smoothly; grou- ting to consolidate the casing meets the requirement, which resolve the technical problems of su- per-large aperture drilling construction in super-thick topsoil.