Abstract: Equilibrium equations of tubular in a deviated well are presented.A differential quadrature element(DQE)incremental iteration method is established to analyze nonlinear buckling of tubular in a deviated well.The method is verified with result of finite element method.It exhibits advantages of easy implementation,low computational cost and higher accuracy.Helical buckling by DQE agrees well with experimental data.The maximum constraint force increases with increasing of upper end load.It is found that the buckling of long tubular is a local buckling problem.The buckling starts from the lower end and propagates upward with increasing applied load.Boundary conditions at upper end have little influence on local buckling of lower tubular.

Key words: tubular, nonlinear, buckling, differential quadrature element method, constraints