A snake-bone flexible drill pipe was designed based on bionics to relieve the overlarge deflecting curvature radius of the sidetrack horizontal well. Specifically, flexible design is carried out for coiled tubing in combination with morphology and mechanism bionics. The ball head+external casing+torque pin structure was used to decompose the drill pipe, and the torque pin was used to transfer torque. Each section can reach a torsion angle of 4.1°, which can alleviate the buckling of the drill pipe in the casing pipe. A maximum bending angle of 5.12° can be generated between sections, and the deflection curvature radius is shortened to 1.8 m. To overcome the directional uncertainty between flexible drill pipe sections of small curvature radius during dispersion, a highly flexible pipe was added at the angle in the flexible drill pipe, which guaranteed a high discharging rate. Based on the multi-body dynamics finite element analysis software ADAMS and the statics simulation software ANSYS, the multi-body linkage dynamics and statics simulation analysis were carried out for the flexible drill pipe as a whole, which confirmed the effectiveness of the described deflecting method. Field experiments were carried out in Well PU 2-365, and the borehole trajectory was calculated based on the data derived from the inclinometer. The deflection section curvature radius could reach 1.8 m, which completed the design expectation.

针对侧钻水平井偏转曲率半径过大的问题，基于仿生学设计了蛇骨式柔性钻杆。具体来说，结合形态学和机理仿生学对连续油管进行柔性设计。采用球头+外壳+扭力销结构分解钻杆，利用扭力销传递扭矩。每节扭转角可达4.1°，可缓解钻杆在套管内的屈曲。断面之间可产生最大5.12°的弯曲角度，偏转曲率半径缩短至1.8 m。为了克服分散过程中小曲率半径柔性钻杆段之间的方向不确定性，在柔性钻杆的角度处增加了高柔性管，保证了高放电率。基于多体动力学有限元分析软件ADAMS和静力学仿真软件ANSYS，对柔性钻杆整体进行了多体联动动力学和静力学仿真分析，验证了该偏转方法的有效性。 。在PU 2-365井进行现场实验，根据测斜仪数据计算井眼轨迹。偏转段曲率半径可达1.8m，完成了设计预期。这证实了所描述的偏转方法的有效性。在PU 2-365井进行现场实验，根据测斜仪数据计算井眼轨迹。偏转段曲率半径可达1.8m，完成了设计预期。这证实了所描述的偏转方法的有效性。在PU 2-365井进行现场实验，根据测斜仪数据计算井眼轨迹。偏转段曲率半径可达1.8m，完成了设计预期。