Effect of coiled tubing initial configuration on buckling behavior in deviated wells

Current sinusoidal and helical buckling models are valid only for initially straight coiled tubing (CT). This paper stresses the effect of the pipe in itial configuration (residual bending) on the sinusoidal and helical buckli ng behaviors in deviated wells. Using the conservation of energy and the pr inciple of virtual work, new general equations are derived for predicting t he sinusoidal and helical configurations of CT. These new equations reduce to those previously published when the CT is initially straight in deviated wells. Numerical examples are provided to show the effect of the initial a mplitude, the inclination angle, and the size of a borehole on the sinusoid al and helical buckling behaviors of CT,with the residual bending.