The second spud of well Dayi 105 has a deviation of about 2 422 m, a horizontal displacement of 1 398 m and a deviation angle of about 35 °.The third spud is drilled with nitrogen. Based on the theory of drill string kinematics and dynamics and referring to the indoor experimental results of drill string dynamics, the drill string whirl was the fundamental reason for the “sawtooth” fluctuation of torque in the clean water stage of nitrogen lifting, drilling stage and bit lifting off the bottom hole circulation stage of well Dayi 105. More drill tool joints and drill tool body collide and rub with the low side of the bottom hole, resulting in the torque at the peak point, At the same time, the viscous friction caused by the cuttings bed formed in the inclined section and the rock powder adhering to the surface of the drilling tool leads to the increase of the average value of torque and friction resistance.In the fixed-point circulation stage when the drilling tool is lifted off the bottom hole, the whirl of the drilling tool induces the friction between the drilling tool joint and the well wall to form a keyway. When the drilling tool joint is in the keyway, the lifting of the drilling tool must overcome the mechanical resistance formed by the keyway, resulting in the increase of friction. At the same time, the friction reducing and torque reducing sand cleaning joint for nitrogen drilling is designed, and the effects of different well deviation angle, build-up slope, WOB and BHA on torque friction are analyzed. Therefore, in order to build the well safely and quickly in nitrogen drilling, it is recommended to further optimize the borehole trajectory in the drilling design, add sand cleaning joints in the BHA, and reduce the whirling effect of the drilling tool by removing the cuttings bed.