Analysis Of Critical Buckling Temperature Of Oil And Gas Pipelines In Permafrost Area

Oil and gas pipelines will be disturbed by frost heave disasters when passing through permafrost area,which might result in bending deflection on pipeline.When being disturbed by frost heave,pipeline is prone to occur buckling under the effect of axial force,which is caused by different temperature between installation and operating.It would threaten the safety of pipeline.In order to find out the buckling law of pipeline and provide a reasonable criterion for pipeline design,theoretical analysis and FE simulation were used to study the buckling law of pipeline in permafrost area.In the theoretical analysis,a mechanical analysis model of straight pipeline was put forward basing small deflection theory,and the Hobbs solution was obtained to explain the buckling mechanism of pipeline in permafrost area.Besides,a mechanical model of pipeline disturbed by frost heave was established.The critical temperature of buckling pipeline was obtained by using least potential energy theory.Then the rationality of the theoretical analysis method was verified by the case of axial buckling at KP 5.2 in Norman Well Pipeline.In the FE simulation,a finite element model of disturbed pipeline was established,and the rationality of the FE simulation method was verified by the case of axial buckling at KP 5.2 in Norman Well Pipeline.Then the parameters such as pipeline geometry and pipe-soil interaction,which might influence the critical buckling temperature,were analyzed.Finally,taking the China-Russia Crude Oil Pipeline(Mohe-Daqing Pipeline)as an example,the limit state of pipeline buckling under bad conditions,and the precautionary methods and suggestions were put forward.