Numerical Computation of Wellbore Dynamic Pressure during Perforating

The wellbore dynamic pressure waves are produced in the perforation liquid after the shaped charges are initiated and then fiercely strike the gunstring, packer, casing and artificial bottom. The impact and damage effect only depend on the amplitude and holding time of dynamic pressures. This paper discusses the simplification of perforators´ explosion with gun in the oil well. On the basis of simplification model, the finite element method is applied to compute the wellbore dynamic pressure under different working conditions. The simulation results indicate that peak compression enhances and the duration of platform pressures obviously prolongs with the perforators´ amount once detonated increasing. The holding time of platform pressure clearly prolongs with the accretion of perforator´s explosive charge mass. The peak compression and holding time of reflection waves decrease with the augment of distance between the end of tubing and artificial bottom. The peak compression and holding time must be lowered if possible to avoid undesirable failures and damage during perforating operation.