西二线渭河水平定向钻孔洞剖面质量控制

Quality control of hole profi le of Weihe River crossing with horizontal directional drilling in the 2nd West-to-East Gas Pipeline Project

近年来,随着西气东输一线、二线的建设,水平定向钻穿越管径已达到1 219 mm,使后续的扩孔孔径增至1 600 mm以上,进而使扩孔级数增加,极易产生孔洞剖面形状不规则,导致坍塌、卡钻、甚至穿越失败。为此,分析了成孔质量的影响因素,包括穿越地层性质、扩孔级差、扩孔直径、泥浆性能、钻具组合、钻具泥浆喷嘴布置,机械操作技术等。提出采用轻量化钻具、调整喷嘴的喷射方向、在钻具直径变化较大处增加导向器、优化钻具组合等方法提高水平定向钻孔洞剖面成孔质量。该方法在西二线渭河穿越施工中成功应用,孔洞质量控制水平得到明显提升,提高了水平定向钻在中粗砂等低承载力地层的穿越能力,降低了施工风险。(图4,表2,参7)

In recent years, with the construction of the first and second West-to-East Gas Pipelines, the diameter of horizontal directional drilling has reached 1 219 mm, so that the subsequent diameter of reamed hole has increased to 1 600 mm plus and the stages of reaming are then also increased, which is easily likely to cause irregular shape of hole profile and result in collapse, sticking and even crossing failure. Analysis shows factors affecting the hole quality include formation properties, reaming differential, reaming diameter, mud properties, bottom hole assembly, the nozzle arrangement of drilling tools and mechanical operation etc. In order to improve the quality of hole profile of horizontal directional drilling, measures such as lightweight drilling tool, adjustment of jet direction of the nozzle, addition of guide at the place drilling tool diameter changed greatly, and optimization of downhole assembly were proposed. This method has been successfully applied in Weihe River crossing construction in the 2nd West-to-East Gas Pipeline Project. The level of hole quality control has been increased significantly. The ability of horizontal directional drilling to cross formations with low bearing capacity like coarse sand has been improved, and the construction risk has been reduced. （4 Figures, 2 Tables, 7 References）