Kinetic analysis method of underground perforation tool under effect of multiple absorbers

Abstract

The invention discloses a kinetic analysis method of an underground perforation tool under effect of multiple absorbers, which includes steps of S1, structure analysis and perforation technique analysis according to the underground perforation tool; S2, establishment of kinetic models of two absorbers; S3, establishment of oscillatory differential equation of the underground tool; S4, establishment of a coupling condition of an oil pipe pillar-absorbers-perforation gun, wherein the pipe pillar kinetic model based on the effect of two absorbers has two coupling borders, the border at the coupling place adopts a force continuity condition, thus the coupling equation can be acquired; S5, solution of the kinetic model of the pipe pillar. The kinetic analysis method has the beneficial effects of reducing the accidents of unsealing failure of a packer for excessive stress, reducing the risk of tester damage caused by excessive acceleration, and avoiding unstability and damage of the oil pipepillar.

Description

technical field [0001] The invention relates to a dynamic analysis method of a downhole perforation tool under the action of multiple shock absorbers. Background technique [0002] During perforating operations, due to the variety and complexity of downhole tools, and the wide application of technologies such as large-charge perforating charges, high-density perforators, sand addition, and well logging, the perforation section tube The impact load intensity of the column explosion has been greatly increased, which puts the entire downhole string equipment in a very complex and harsh stress environment. Therefore, the contradiction between improving the perforating efficiency and reducing the damage to the pipe string caused by the impact load of perforation can be effectively overcome, the accidents of unsealing failure of the packer due to excessive force, and the failure of the test instrument due to excessive acceleration can be reduced. It has become a major problem to ...

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Problems solved by technology

In 2011, according to the formation testing process and considering the influence of various downhole parameters, LI et al. established a mathematical model for the mechanical analysis of the test string in the entire operation stage, and solved it with the differential method to give the tension, torque, and stress along the entire string. , safety factor, stability, elongation and other parameters, but did not study the dynamic behavior characteristics of other downhole tools

In 2015, Huang et al. established a longitudinal vibration dynamics model of the test tube and shock absorber, and studied the influence of perforation parameters on the dynamic characteristics of tubing and packer, but ignored the influence of the mass of the shock absorber.

In 2017, Liu et al. established a dynamic model of the tubing string-shock absorber-perforating gun considering factors such as fluid friction and the structure's own gravity, and carried out research on the dynamic characteristics of downhole tools with parameters such as charge amount and tubing length. However, it does not consider the influence of shock absorbers at different positions on the dynamic characteristics of downhole tools

For the research on the calculation method of perforation load, scholars mainly put forward the classic calculation method of perforation load based on the basic idea of ​​explosive explosion, but its calculation accuracy is quite different from that of actual engineering.

In 2016, Zhang Wenbin et al. conducted research on the pressure field generated at any time during the detonation of perforating bullets, established a calculation model for perforation impact load, and obtained the influence of different parameters on impact load. The obtained load calculation formula cannot be effectively applied to actual engineering. middle

[0004] In summary, most scholars focus on the buckling deformation analysis and static analysis of the perforation string in the direction of the perforation string, and lack of consideration of the influence of working conditions on the dynamic characteristics of the perforation string. , there is no downhole tool dynamic model based on multiple shock absorbers. For the calculation method of perforation impact load, most of them use theoretical explosion load calculation formula or simulation experiment method to study, and no field experiment research on oil and gas well impact load has been carried out. , and there is no study on the influence of different numbers of shock absorbers on the dynamic characteristics of downhole tools

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