双弯螺杆纠斜效果分析与应用

双弯螺杆是指弯接头加弯壳体螺杆的钻具组合形式。采用双弯螺杆纠斜，可以获得较大的造斜率，解决在特定条件下单弯螺杆纠斜困难的问题。选择合适角度的弯接头，减少双弯螺杆造斜进尺长度，是控制井眼“狗腿”度，保证后期工作（扩孔和下套管）顺利进行的重要因素。以在大口径钻孔中纠斜为例，列举了使用单弯螺杆纠斜遇到的困难，通过双弯螺杆造斜效果的分析，提出了一套采用双弯螺杆进行纠斜的工艺，最终实现了钻孔的纠斜成功。

Analysis on Double-bend Screw Drilling and the Application

Double-bend screw refers to the drilling tools combination form of bending joint and bend housing screw. The use of double-bend screw for hole straightening can get larger built-up rate to solve the difficult straightening while using the single-bend screw in some specific conditions. Selecting proper angle of bend joint and shortening deflecting distance of double-bend screw are important factors to control dogleg angle, which can ensure later work of smooth reaming and casing. Take the straightening case in a large diameter drilling, the difficulties encountered in straightening with single-bend screw are listed, by the analysis on the deflecting effect of double-bend screw, a set of straightening technology with double-bend screw is put forward and successful borehole straightening is finally realized.