Research On Evaluation Of Oil And Gas Pipelines Residual Strength After Corroded

With the change of energy industry and the development of the national economy, thedevelopment of natural gas and fuel oil has become the most urgent task. The transportationof natural gas and oil fuel depends on the pipeline, therefore, the natural gas and fuel oil pipeswill be the development direction in the future. However, due to the pipe environment factors,the pipeline is corroded easily, which leades to all kinds of accidents, casualties and propertylosses. So the research on evaluation of oil and gas pipelines residual strength after corrodedis imminent.In this paper, through comparing with the existing evaluation standard, the feasibility andveracity on evaluating the corroded pipeline in finite element method is discussed andsummarized. The main research work is such as:1. The development of pipeline transportation was introduced, the research backgroundand significance of the residual strength evaluation after pipeline corroded, and the researchstatus at home and abroad was analyzed simply. The research contents and research methodsof this paper were given finally.2. The API579principle on evaluation of residual strength of three kinds of pipelinescorroded was expounded. The principle not only reduces the conservative shortcoming of theASME B31G criteria, but also can evaluate multiple corrosion defects, welding line corrosion,and corrosion of ring to the larger size corrosion. The residual strength corrosion of ring to thelarger size corrosion, the axial size larger local corrosion and the loose distribution forcontinuous pitting corrosion were researched.3. The basic theory of finite element was simply introduced, and then the corrosionpipeline was simulated by using the ANSYS software. Firstly, the pipelines of uniformcorrosion, groove corrosion and continuous pitting corrosion were simulated, then equivalentstress nephogrames under the action of internal pressure were got and residual strength ofpipeline corrosion was confirmed. Comparing the computational results with the rules of API579, the results proved that the rule of API579standard is conservative, which proved thatFEM is accurate.4. The three elements of the length, width, and depth from the uniform corrosion weresimulated and studied respectively in ANSYS software. The influence of uniform corrodedpipeline residual strength. The result has scientific significance and guiding role to the actualevaluation of corroded pipeline engineering. The result plays a direction mark to improve theexisting evaluation method, and provides a theoretical basis.