Computational Modeling of Shock-Wave Loading due to the Detonation of a Cylindrical Explosive Charge in a Drill Pipe

Abstract

To develop a technology of drill pipe fracture and extraction from a well at a depth of more than 5000 m, we performed a numerical study of shock-wave loading of the inner surface of the pipe by the detonation of a special cylindrical charge. Two cases of detonation of the cylindrical explosive charge are considered: plane-front detonation and diverging spherical detonation. The computational model is a layered structure which consists of a cylindrical explosive charge in a copper case, a steel pipe, and drilling mud. The shock-wave impact on the drill pipe is calculated in a three-dimensional formulation using the multicomponent Eulerian approach. The calculations confirmed the possibility of drill pipe fracture in the region of the lock joint. It is shown that shock-wave loading by the plane-front detonation causes much more damage to the pipe than the impact by diverging spherical detonation. The minimum charge length sufficient for drill pipe fracture was determined by additional calculations.