ИСТИНА

The work is devoted to the numerical simulation of a gas-metal-liquid jet formation during the initiation of a charge of solid explosive inside the shell device. The purpose of the study is to optimize the form of the squib used in the oil and gas industry. The advantage of cumulative perforators over other technological schemes is the ability to create elongated channels in complex targets. The paper proposed a mathematical model for calculating the initiation of a shaped charge, followed by deformation and destruction of the charge body, the appearance of a cumulative jet penetrating through the metal layer and casing. The shape of the inner shell, called the liner, significantly affects to the cumulative jet characteristics. The outer shell of the projectile, as a rule, is made of steel, the inner one can be made of both steel of various thickness, and of aluminum, copper, tungsten or other metals. You can achieve an increase in the length of the channel in the target by 20-25% due to changes in the parameters of the liner. In experimental and theoretical works, it was found that at angles less than 13o the jet has insufficient force. When the angle at the tip of the liner cone changes from 13o to 46o, the jet speed gradually increases, and then at jet angles greater than 46o the jet speed decreases. The original program code was created based on a mathematical model [1], which allowed to calculate the detonation of solid explosives, deformation of the igniter shell when varying the following parameters: the material of the outer shell and liner, explosive, and the shape of the squib. Mathematical modeling of charge initiation with subsequent penetration of a cumulative jet into a combined barrier allows optimizing the charge characteristics and cumulative perforator design taking into account the geometry of the charge arrangement, as well as improving the hydrodynamic connection between the oil and gas reservoir and well. The reservoir macrofracturing is simulated by splitting the Lagrangian computational grid. It is established that for a given form of steel pyrocartridge, the speed of the jet substantially depends on the angle and has a maximum value of 4785 m/sес at an angle of a conical liner of 38 °. Acknowledgements: This work was supported by a grant from the Russian Foundation for Basic Research №18-07-01303 А.