Computation Model of the Failure Probability and Reliability for the Submarine Oil and Gas Pipeline with Corrosion Defects

Long distance submarine oil and gas pipeline usually has a failure model of inside or outside corrosion. This will reduce the wall thickness and weaken the pipeline to resist fatigue load ability. According to the feature of submarine pipeline structure and load, the failure probability model and reliability evaluation is put forward based on the Monte Carlo method and normal distribution function. By the DNV OS F101 submarine pipeline system standard, there are four limit state, such as serviceability limit state (SLS), ultimate limit state (ULS), fatigue limit state (FLS) and accidental limit state (ALS). For serviceability limit state, the failure probability calculation model is put forward with comprehensive stress of finite element model based on the inside pressure load and temperature load of the vertical and straight pipeline. By use this computation model, the results of the failure probability and safety level are more accurate, it is very useful for the integrity and safety management of the submarine pipeline.