Shaped Charge Jet Penetration Process Of Numerical Simulation Method

Perforation of oil and gas well was a very important completion operation. Late-model perforation technique such as hydraulic and laser perforation had developed fully in petroleum perforation field at home and aboard as a result of driving of market economy. But it wasn't extended and applied largely because of long periodic time of operation and high outlay of investment. Shaped charge by means of detonation took a major part in completion operation, which was fast, highly active, cheap and significant effectiveness. Perforating bullet was the nucleus of gun-perforator. High temperature, heavy pressure and high energy density shaped charge was produced after detonation the bullet. Gun-perforator wall, spigot and rocks with oil were penetrated in extremely short time (microsecond or millisecond magnitude). Effective channel running oil was formed when well casing and stratum layer were connected reciprocally. As a result, the quality of perforating bullet, that is the design with reason of perforating bullet's structure and shaped charge was one of the most important factor in perforating engineering. Additionally, perforating progress took a lot of capital in oil field. If new-model perforating bullet had been designed, and experimented in practice, it would bring big risk. Therefore, economic losing was enormous. The method of numerical simulation experiment was the most effective method.Fluid mechanics principle of shaped charge and penetration were analysed systematically by use of theoretical analysis and numerical simulation. An effective software was selected to numerical modeling and emulation analysis the nonlinear mechanical progress, including collapsing of linear, forming and extruding of shaped charge and penetrating of gun-perforator wall, spigot, cement circle and rocks with oil after bullets were denoted. Effective calculation results were obtained.The main research contents include:1. In order to research the liner of perforating bullet effect on shaped charge jet after shaped charge explosion, the mechanism of shaped charge jet formation was analysed, and numerical simulation of the jet formation process was made with the explicit dynamic finite element analysis program. And the liner's structure, such as cone angle, well thickness,shape, influenced velocity of shaped charge jet. So the relations between jet velocity and liner were found.2. The distribution character of the parameter, which is called velocity of shaped charge jet, was analysed, and the results between shelled model and no shell one are compared. The results of numerical simulation are in agreement with physical phenomena and laws of jet formed by circular cone shaped charge blasting.3. Numerical simulation of penetration through the wall of perforating gun were made. And the results of numerical simulation are discussed. The distribution character of the parameter, which is called height of burst, is analysed. Besides, penetration through gun-perforator wall with shell and no shell were numerical calculated. The shape of shaped charge was different, and with the explosive wave bursting, the shell crashed with gun-perforator wall when shaped charge penetrated. Surface bulging was found on the wall of gun-perforator as a result of serious deformation.4. Based on simulation of penetration through gun-perforator wall, dynamic model was built including spigot, cement circle and rocks with oil. Corresponding constitutive and material parameters were found. Penetration process of breaking pit, quasi-steady state and termination was numerically calculated. And penetration process was truly reflected through the results above.The study indicates that the calculation model and simulation method are reasonable and feasible, so can be applied to the optimizing design for shaped charge jet,which may be used for reference to manufacture and scientific research of perforating bullet.