考虑套管边界和液柱高压的射孔液压力脉动规律分析

Analysis of perforation liquid pressure pulsation law considering complex boundary conditions at the bottom of a well

射孔爆轰冲击和压力脉动常引发射孔段管柱振弯、振断等事故。考虑射孔液高压、狭长套管边界对冲击波传播的影响,考虑射孔弹密集排列引起干扰的影响,考虑相变界面冲击波传播的连续性,基于Tait方程,建立冲击波初始压力分析方法;考虑套管狭长边界条件限制,阐明冲击波传播规律,构建直达冲击波分析方法;基于波的反射原理,建立套管交界面、射孔液参数的近似图解和波反射的分析方法;应用直达和反射波的叠加原理,建立压力脉动分析方法。经过实际射孔井验证表明,反射波压力明显大于入射波,反射波压力随爆距增大而减小;射孔弹按16孔/m排列,附近4颗弹将对某弹产生的冲击波存在影响,其余可忽略;压力衰减时间增长了30μs。

Perforation detonation shock and pressure pulsation often lead to accidents,such as bend and break of the column of the emission hole because of vibration.The high pressure of the perforating liquid and the narrow casing boundary that affect the shock wave propagation,and the influence of interference caused by the dense arrangement of perforating bullets were considered.Furthermore,continuity of shock wave propagation at phase change interface was also considered.An initial pressure analysis method of the shock wave was established according to the Tait equation.The law of shock wave propagation was clarified and an analytical method of direct shock wave was established,which both consider the narrow boundary conditions of casings.According to the principle of shock wave reflection,the approximate graphic method was used for solving the parameters of the perforation liquid and the casing interface.The pressure pulsation analysis method was established by applying the superposition principle of direct and reflected waves.After actual perforation verification,the results show that the reflected wave pressure is significantly larger than the incident wave pressure,and the reflected wave pressure decreases with the explosion distance.When perforating bullets are arranged in 16 holes/m,the four nearby bombs affect the shock wave generated by a certain bomb,and the rest can be neglected.The pressure decay is increased by the initial pressure time of the perforating liquid by 30μs.