Open Access

ARTICLE

The Post-Buckling Behavior of A Tubular String in An Inclined Wellbore

Deli Gao¹, Fengwu Liu¹

1 Key Laboratory of Petroleum Engineering in the Ministry of Education, China University of Petroleum, Beijing 102249, China. E-mail: gaodeli@cup.edu.cn; liufengwu2008@gmail.com

Computer Modeling in Engineering & Sciences 2013, 90(1), 17-36. https://doi.org/10.3970/cmes.2013.090.017

Abstract

A down-hole tubular string in an inclined wellbore, under variable axial and torsional loading, may simultaneously undergo a sinusoidal as well as helical buckling, at different sections. In this paper, the buckling equation for a tubular string, in an inclined wellbore, subjected to axial and torsional loading, is established by an equilibrium method. The analytical solutions for the buckling equations, for sinusoidal and helical configurations of buckled tubular string, are obtained by Galerkin and nonlinear scaling methods. Methods for computing the contact forces between the buckled tubular string and wellbore, are developed. The analytical solutions are in good accordance with the numerical results, for the nonlinear buckling equation. The critical loads for sinusoidal as well as helical buckling of a down-hole tubular string are determined, using the constraint condition under which the contact force is nonnegative. Thus, the post-buckling behavior of a tubular string, with different configurations, in an inclined wellbore, is determined by the presented analytical method.

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