伊犁盆地砂岩型铀矿孔斜防控实践分析

Deviation prevention and control for deep holes in sandstone-type uranium mines in Yili Basin

近年来在新疆伊犁盆地施工的砂岩型铀矿钻孔孔深大多在600~1000 m之间,钻孔终孔测井平均偏斜距在28 m左右,孔斜控制是影响伊犁矿区钻孔成孔质量的主要技术难题。伊犁盆地钻探施工多采用普通取心钻进工艺,成孔的钻杆与孔壁间的环状空间大,盆地内复杂地层引起的钻孔扩径现象普遍。普通取心钻进钻杆刚度小,钻杆在孔内转动时甩动弯曲幅度大,是导致孔斜控制困难的主要影响因素。中深孔钻孔偏斜距较大,影响地质成果质量和钻探经济效益。通过设计适合在伊犁盆地复杂地层内使用的扶正器并优化钻具组合,使伊犁盆地试验区内施工的中深孔平均偏斜距得到了大幅度的下降,该技术方案对同类型钻孔施工具有一定的借鉴性。

In recent years,drilling depth in the sandstone-type uranium mine in Xinjiang Yili Basin is mostly between 600m and 1000m with measured average bottom hole deviation about 28m,and borehole deviation control is the main technical problem affecting the quality of drilling holes in the Yili mining area.Exploration drilling is mostly done by conventional core drilling in Yili Basin,where borehole expansion caused by complex formations is common.Low rigidity of the drill pipes and the large swinging bending range of the drill pipe due to its rotation in the hole are the main factors that cause the difficulty in controlling deep hole deviation in the sandstone-type uranium mine in Yili Basin.Large deviation in medium and deep holes affects the quality of geological results and drilling economic benefits.With proper design of the centralizer suitable for the complex formation in Yili Basin,and optimization of the drilling string combination,the average deviation in the deep holes drilled in sandstone-type uranium mines in the Yili Basin test area has been greatly reduced.The deviation prevention and control measures can provide some reference for similar drilling works.