复合射孔压力加载下铜柱测压计测试实验和数值分析

Experiment and numerical analysis of the test of copper cylinder pressure gauge under combined perforation pressure

进行基于铜柱测压和实测压力时间曲线的石油井射孔压裂实验,建立铜柱测压计的数学模型,并采用交互式计算方法得出其作用过程的解析解。分析结果表明,井下射孔压裂过程中,压力上升沿很陡,活塞在外部压力达到峰值时,速度很大,会继续压缩铜柱直到速度为零。活塞的运动可以分为加速和减速撞击2个过程。活塞的最大速度决定了铜柱测压计最终测试值,且与速度成正比。射孔脉冲压力加载过程中铜柱测压计的误差取决于压力上升时间、脉冲宽度、峰值压力等影响因素。火炮膛压加载下铜柱测压计误差较小。

A experiments of downhole perforation and fracturing pressure live test based on copper cylinder and corresponding p-t curves at the same time were performed.A mathematical model for copper cylinder gauges was developed and obtained the analytical solution of its working process was obtained by using an interactive calculation method.The results show that the test value,which copper cylinder got in downhole perforation and fracturing,may be larger than the true value or be smaller,mainly depending on the pressure rise time,pulse width,peak pressure and other factors.The process of downhole perforation and fracturing is different from artillery chamber pressure,the pressure rise time is short.Velocity of the piston is still large when external pressure passed the peak and the piston will continue compress the cylinder until its velocity reduced to zero.In this process,the piston can be divided into two parts： Rapid acceleration and deceleration during impact.The maximum value of piston velocity is determinants for the final test,the greater the speed the greater the test value,It is proposed that copper cylinder pressure-measuring gauge with light quality piston be developed to reduce copper cylinder test error in this case.