Study On Failure Risk And Early Warning Of Corroded Subsea Oil And Gas Pipeline Based On Time-varying Reliability

Pipelines are the basic means of transportation for oil and natural gas resources.The construction mileage has increased year by year.Pipeline failure accidents will not only bring huge economic losses,but also cause environmental pollution or casualties,and the social impact is bad.In this paper,by studying the corrosion failure problem of subsea oil and gas pipelines,aiming at the shortcomings of traditional reliability methods used in previous pipeline failure assessment,the model of pipeline time-varying failure probability and early warning is proposed to enrich the theoretical method of pipeline reliability assessment and improve the subsea oil and gas pipeline.Operational safety management.This paper uses literature research methods,combined with qualitative and quantitative analysis methods,to study the time-varying failure risk and early warning of corrosive seabed oil and gas pipelines,and have achieved the following conclusions and results.(1)Theoretical research.Based on the theory of reliability and time-varying reliability theory,the significance of the "first crossing rate" is analyzed,and the different calculation principles and methods of the crossing rate are compared,and an improved calculation method is proposed.(2)Corrosion and failure analysis.The principle and type of corrosion of pipelines are combed,and the failure mode of pipeline corrosion is proposed by means of failure analysis.Corrosion was evaluated based on corrosion time-varying failure size and area data,and different models of fitting corrosion rates were compared.(3)Time-varying failure probability model.The applicability of the calculation criteria of residual strength of different pipelines is analyzed.According to the time-varying reliability theory,the time-varying failure probability model of the relationship between residualstrength and operating pressure of pipelines is established.Case studies were used to identify the sensitivities of the time-varying failure probability of the pipeline.(4)The construction aspect of the early warning model.Combined with the knowledge of early warning theory,the risk warning degree of pipeline failure probability dimension and pipeline system safety rating dimension is established with reference to relevant standard norms;risk warning for pipeline system is carried out.In view of the fact that the additional load of the time-varying failure probability model considers the pipeline operating pressure,the next step can be added to the complex factors to establish a more realistic pipeline time-varying failure model.