| Summary: | The challenges such as large frictional drag, difficult weight-on-bit transmission, and low rate of penetration are frequently met in modern directional drilling, especially in horizontal well drilling. This study presented a nonlinear dynamic simulation model of horizontal well considering the random interaction between drill string and wellbore as well as bit and rock. In this study, the dynamic characteristics of the bottom hole assembly during drilling with and without agitator as well as the working mechanism and optimization parameters of the agitator were simulated and compared. The field application of the agitator is also simulated for the design and working parameter optimization. The results show that using agitator can improve the weight-on-bit transmission efficiency and reduce the frictional drag, tropsh-pressure, and occurrence probability of drill string buckling. The optimal installation position of the ∅172 mm agitator obtained in this study is [200, 300] m away from the bit, the optimum frequency range is [3, 17] Hz, and the optimal impact load is 100 kN.
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