完井剪切球座冲击失效分析及设计改进

Impact failure analysis and design optimization of completion shear ball seat

由于目前海上井况的复杂性和完井工艺的多样性,在送球坐封封隔器或开关滑套作业中因送球导致剪切球座提前剪切失效的问题愈加突出。在分析完井作业过程中常用单独送球入座和单球逐级剪切多级球座受冲击剪切工况基础上,综合考虑球、液体冲击和地层漏失等影响因素,建立了送球入位时作用于球座及其剪切销钉冲击失效模型。案例分析和模拟实验结果表明,所建立的剪切球座冲击失效模型具有较高的精度。结合不同完井工艺管柱工具外径、中心管长度和承压能力等因素,利用建立的剪切球座冲击失效模型设计了2种新型免冲击旁通球座。实验测试及现场应用表明,2种新型免冲击旁通球座可适用于不同工况完井作业,具有较好地推广应用价值。

At present,due to the complicated offshore well conditions and well completion diversity,the problem of pre-mature shear failure of shear ball seat during ball pumping down to set the packer or sliding sleeve switching is prominent.According to the analysis on the impact shearing conditions of landing the ball on seat and shearing the multi-stage ball seat step by step,the impact failure model of ball seat and its shearing pin was established by taking into account the factors such as ball/liquid impacts and formation leakage.Case analysis and simulation results show that the established impact failure model exhibits high accuracy.Based on this model,two new non-impact by-pass ball seats were designed by considering the factors such as outer diameter of tools,length of mandrel and bearing capacity of different completion strings.Experiments and field applications show that the two new impact-free by-pass ball seats can be applied in completion operations under different conditions,and they present good popularization and application value.