A 3D impact dynamic model for perforated tubing string in curved wells

Perforating-test joint operation in oil&gas wells may causes strong impact vibration of downhole tools which can easily lead to buckling of tubing string, falling off of tools and damage of instruments. A 3D impact dynamic model of the perforated tubing string is established by using d'Alembert's principle and microelement method, and solved by the Newton difference method, taking into account the well trajectory, internal/external fluid pressure, interaction forces between the tubing and casing, and the coupling effect of per-forating gun-shock absorber-tubing string. Due to the complexity of the verification, firstly, a similar experiment is carried out to test the accuracy of the model preliminarily. Secondly, through a case analysis, the feasibility of the model in the perforation impact dynamic analysis of tubing string in curved wells is further investigated. Both the two tests show that the model proposed in this paper has good calculation accuracy and can meet the needs of perforation shock vibration analysis of tubing string in curved wells perforation. (c) 2020 Elsevier Inc. All rights reserved.