The authority of Henan Province has taken the coal looking under the extra-thick overburden in eastern and southeastern ar-eas of the province into the“12th Five-year Plan”key exploration projects. Since most of the overburden thicknesses are over 600m, thus overall borehole depths should exceed 1200m. If using conventional wire-line coring technology should lower down wall protecting casings, demanding mud performance and high cost of tubing and mud. Meanwhile conventional tools have low strength, high accident rate of break offs and thread offs, thus borehole safety can not be guaranteed. Furthermore, the traditional coring has low drilling efficien-cy and high labor intensity. In view of the above problems, high strength wire-line coring rod, collar, corer and bit have been developed, as well as flushing fluid prescription and drilling regulations and parameters under different strata and coring conditions set down. Appli-cations have shown that the high strength wire-line coring tools have characteristics of high coring rate and rig efficiency per month, drilling tool safety, low labor intensity and relatively low production cost. Thus basically settled technical hard nuts of drilling within ex-tra-thick overburdens without wall protection casing, common mud can satisfy construction requirements etc.%河南省把豫东和豫东南地区巨厚覆盖层下找煤列入“十二五”重点勘查项目。由于巨厚覆盖层大部分厚度在600m以上，钻孔深度均超过1200m，采用常规绳索取心工艺必须下护壁管，施工中对泥浆性能要求苛刻，管材和泥浆成本较高；同时深孔施工常规钻具强度低，断钻、脱扣事故率高，孔内安全得不到保证。而传统的提钻取心工法钻探效率低，职工劳动强度大。鉴于以上问题，研制高强度绳索取心用的钻杆、钻铤、取心器和钻头等钻具，并制定了不同地层和取心条件的冲洗液配方和钻进规程参数。应用表明，高强度绳索取心工艺具有取心率和台月效率高，钻具安全，工人劳动强度低，生产成本相对较低的特点，基本解决了在巨厚覆盖层施工不下护壁套管，普通性能的泥浆就能满足施工要求等技术难题。
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