Summary
A comprehensive buckling model, a group of fourth-order nonlinear ordinary
differential equations, was derived by applying the principle of virtual work.
Lateral friction force is included in this model. The equations were normalized
to make the solutions independent of the wellbore size, type of pipe, and mud.
The critical sinusoidal buckling load of tubing with different boundary
conditions typically seen in drilling and well-completion applications was
analyzed on the basis of the analytical solution of the linearized buckling
equation. The results show that the effect of the boundary conditions can be
neglected when the dimensionless length of tubing is greater than 5π.
The authors further investigated the effects of friction on sinusoidal buckling
by applying the principle of virtual work. The critical conditions for
initiating sinusoidal buckling were determined by a group of three nonlinear
equations. A perturbation solution of these nonlinear equations was obtained.
It was found that the critical loads for sinusoidal buckling will increase by
30 to 70% for friction coefficients between 0.1 and 0.3. The authors also
conducted an experimental study. The experimental results, including both data
obtained by the authors and results published by other researchers, support the
proposed model.
Introduction
Various pipes, including drill pipe, casing, tubing, coiled tubing, and
sucker rods, are widely used in drilling, well completions, formation
stimulation, water injection, and the pumping of wells. During drilling,
completion, production, or stimulation operations, the drilling pipe or tubing
may be subjected to some degree of axial compression or the pressure inside the
pipe may exceed the external pressure. In both cases, the pipe may lose its
stability and buckle into a sinusoidal or helical shape. Consequently,
stability and post-buckling analysis of pipe in various kinds of wellbores
attracts intense interest from the petroleum industry.
© 2009. Society of Petroleum Engineers
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History
- Original manuscript received:
16 December 2007
- Meeting paper published:
4 March 2008
- Revised manuscript received:
25 November 2008
- Manuscript approved:
27 November 2008
- Published online:
20 August 2009
- Version of record:
22 December 2009