Bachu Block is an important exploration and development area of Sinopec in Northwest China, with vast area to be explored, large depth of the well, and few completed wells, and few offset well materials can be taken as the reference in drilling operation, the formation features and drilling difficulties were analyzed in the paper, including palaeogeography, complex and hard lithology, gypsum, mudstone and high pressure salt water existing in some formations, resulting in low penetration rate, tight hole, drill pipe stuck, and hole wall sloughing, etc. The difficulties also lead to high trouble rate and longer drilling cycle. In order to solve these problems, the upper formations were drilled with KCl-polymer drilling fluids, and lower formations were drilled with KCl-polysulfonate drilling fluid. And plugging material screening, bottom hole assembly optimization, and bits optimization for deep formation drilling were also taken as the countermeasures. Through onsite applications, the penetration rate raised significantly, which provided a good example of drilling in mis area. The suggestion was also proposed to use a compound drilling mode, gear-down turbine, little bent screw and borehole reforming tools to raise the drilling rate.%新疆巴楚探区是中石化在西北地区的一个重要勘探开发区域,勘探面积大,井深,完钻井少,可参考资料少.该区钻井施工难点主要是钻遇地层年代古老、岩性复杂而坚硬,部分地层存在石膏和膏质泥岩及高压盐水层,钻井工作存在钻速慢、缩径、卡钻及地层坍塌等技术难题,致使钻井复杂故障率高、周期长.针对这些难题,提出了上部地层采用KC1-聚合物钻井液体系、下部采用KCl-聚磺钻井液体系,优选封堵材料,优化钻具组合,深部地层优选钻头等技术对策.通过现场实施,钻井提速提效效果显著,为该区的进一步勘探开发提供较好的借鉴作用,并提出了用减速涡轮复合钻井方式、试用小弯度螺杆和井壁修复器等提速提效建议.
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