Underground perforation test tool string optimization method based on packer stress analysis

Abstract

The invention discloses an underground perforation test tool string optimization method based on packer stress analysis. The method comprises the steps that S1, a tubing string-shock absorber-perforating gun dynamic model is established; S2, an oscillatory differential equation of a perforated string is established; S3, an oscillatory differential equation of a shock absorber is established; S4, a tubing string-shock absorber-perforating gun coupled oscillation equation is established; and S5, a tubing string-shock absorber-perforating gun partial differential equation is solved. The method has the advantages that research about influences of the length of an oil tube and the explosive charging amount of a perforating bullet on underground tools is carried out, and the stress of a packer is increased along with increase of the length of the oil tube according to the research; the portion, prone to spiral buckling, of the oil tube is at a certain position at the bottom and in the middle of the oil tube; the tension and pressure borne by the oil tube are increased sharply along with increase of the explosive charging amount, so that the oil tube is prone to spiral buckling more easily, and theoretical guidance is provided for string design; the damage risk of a tubular column is lowered; and the underground tools are protected.

Description

technical field [0001] The invention relates to an optimization method for downhole perforation testing tool strings based on packer stress analysis. Background technique [0002] The purpose of perforation operation is to form a passage between the wellbore and the oil and gas layer, which is a key link in the exploitation of oil and gas fields. The development and improvement of perforating technology has important practical significance and practical value for the efficient exploitation of oil and gas fields. The perforating operation requires the use of a perforating string system, which includes a shock absorber and a perforating string. The perforating string includes tubing and a perforating gun. The tubing is connected to the shock absorber, and the shock absorber is connected to the perforating gun. The perforating gun is filled with explosives for explosive perforation. When the perforating gun is perforated, the impact force generated by the explosion inside the ...

AI Technical Summary

Problems solved by technology

[0006] The perforated tubing string vibrates under the action of blast impact load, and there are few studies on its dynamic behavior, especially the coupling research on the tubing string-shock absorber-perforating gun. However, its damage to the tubing string and Failure has a great influence, and it is very important to understand the coupling mechanism between them to solve the impact of explosion load on pipe strings. However, there are few researches on this aspect at home and abroad

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