Time-varying Risk Assessment And Integrity Management For Aging Submarine Pipeline In Prolong Life Period

Oil and gas energy is an important strategic resource,which have a great effect on national economy and safety.With the rapid development of our country's economy,the demand for oil and gas resources is increasing year by year,and the development and utilization of marine oil and gas resources is also rising.Submarine pipeline's working condition is complex,which has a high failure probability,the failure of submarine pipeline will cause huge economic loss,oil and gas production halts,pollution to the Marine environment,which affect the normal production and supply of oil and gas.Therefore,the safety analysis on submarine pipeline of prolonging life period,which can ensure the work of domestic old submarine pipeline safety,avoid the economic loss and environmental pollution that caused by pipeline failure.In this paper,considering the real condition of submarine pipeline aging,based on Marine engineering,reliability engineering,Bayesian theory,integrity management theory and finite element simulation software,it research on dynamic risk of submarine pipeline which is under complicated conditions,and pipeline corrosion residual life and integrity management model.The above research can provide technical support for prolonging life decision and safe operation of submarine pipeline.The following is main research outcome of this paper.1 The failure identification of aging submarine pipeline and dynamic risk assessment of leakage accidentBased on the barb map combined with hierarchical analysis method,we conduct a failure risk analysis of aging pipeline,weights calculation of risk factor to objective pipeline,establishing failure risk identification model of aging submarine pipeline.We get safety barrier failure probability by Bayesian network reasoning forward prediction,and get safety barrier factor posterior probability by Bayesian to diagnosis reasoning ability.Meanwhile,we get the most likely portfolio model of basic event which can lead to pipeline leakage,and give reasonable advice to protect safety barrier from failure,give a theoretical support for dynamic risk management of aging submarine pipeline.2 The assessment of corrosion residual life for aging submarine pipeline systemThe corrosion of pipeline finite element model is established,we conduct a finite element analysis by considering dimension parameter of corrosion area.Put forward the characteristic parameters of corrosion depth have a significant influence on the average stress of pipeline's corrosion area.With the increase of corrosion depth,the stress corrosion area is bigger and bigger.Based on grey theory,the corrosion depth of grey prediction model is established.According to the pipeline historical statistical data,predict pipeline corrosion depth change trend.Based on finite element analysis software ANSYS,the pipeline corrosion defects model is established,conduct a research on the application to prediction of corrosion residual life of submarine pipeline.Then,an assessment model of corrosion residual life is established.3 An integrity management model of aging submarine pipeline during prolonging lifeFrom the sight of integrity management implementation demand of submarine pipeline which is in prolonging life,make sense the meaning of integrity management of aging pipeline,based on technical standard system,file system,integrity evaluation technology and change management mode,also considering special requirements of pipeline which is in prolonging life,and from the data collection and sorting,high consequence identification,risk assessment,integrity assessment,repair and maintenance,effectiveness evaluation of work blanks,according to this five aspects,aging submarine pipeline integrity management model is established.4 Aging submarine pipeline digital analysis and management softwareDeveloping digital analysis and management system of aging submarine pipeline by Visual Basic 6.0 language,The software adopts the parameterization,modularization and information technology to realize risk assessment and integrity management research on aging submarine pipeline that is in prolonging life period,analyzing data calculation and conducting post-processing by the scientific computing software MATLAB and the finite element simulation software ANSYS,providing application system platform for aging submarine pipeline which is in prolonging life period.Software generally is composed of several modules: attribute parameter setting module,user management module,risk identification module,the time-varying risk assessment module,the corrosion residual life evaluation module,integrity management module and data output module.