防喷器（blowout preventer, BOP）是关键的井控设备，其中剪切闸板防喷器是防止井喷事故的最后一道防线，其在极端工况下的剪切性能对于钻井作业安全至关重要。以某超级剪切闸板防喷器为研究对象，通过显示动力学模块开展闸板防喷器剪切数值分析，将仿真结果与试验及理论计算结果对比，验证了模型的准确性及适用性。为探究极端工况对闸板防喷器剪切能力的影响，开展了高压工况、偏心工况和窜动工况下的钻杆接头剪切性能评估，并运用响应面方法建立了极端工况下的剪切力预测模型。基于极端工况下的剪切力预测模型和闸板防喷器的实际剪切能力，确定了极端工况下的剪切失效场景。结果表明：剪切应力理论值和仿真值的相对误差均小于3%。在剪切过程中，轴向拉压载荷越大越不利于剪切，而一定的偏移距离则有利于剪切。研究成果可以为预防闸板防喷器剪切失效提供技术指导。

The blowout preventer (BOP) is a key well control equipment, in which the shear ram BOP is the last line of defense against blowout accidents. Therefore, its shear performance under extreme working conditions is crucial for the safety of drilling operations. A super shear ram BOP was taken as the research object, and the numerical analysis was carried out by using the dynamics module. The simulation results were compared with experimental and theoretical values to verify the accuracy and applicability of the model. In order to investigate the influence of extreme working conditions on the shear capacity of the ram BOP, the shearing performance of the drill pipe joints was evaluated under high pressure working conditions, eccentric working conditions and moving conditions. The response surface method was applied to develop a shear force prediction model under extreme working conditions. Based on the prediction model and the actual shearing capacity provided by the ram BOP, the shearing failure scenarios under extreme working conditions were determined. The results show that the relative errors between the theoretical values and the simulation results are less than 3%. In the shearing process, the larger the axial tension and compression load, the more unfavorable the shearing. While the certain deviation distance is conducive to the shearing. The research results can provide technical guidance for preventing the shearing failure of ram BOP.