Study On Leakage Risk And Emergency Strategy Of Underwater Oil Pipeline

This dissertation is supported by the National Key R&D Program of China “Risk assessment and prevention technology for offshore oil and gas pipelines and onshore terminals”and carries out research on underwater pipeline leakage risks and emergency strategies,and proposes ecological risk assessment,comprehensive risk assessment,and emergency pumping for underwater pipelines.This research works as a reference for improving the risk assessment of underwater oil pipeline leakage and the level of emergency prevention and control.The main research progresses are summarized as follows:(1)Ecological risk assessment of underwater oil pipeline leakageEstablish an ecological toxicology model for underwater oil pipeline leakage,carry out dynamic multi-medium migration analysis of oil spill via fugacity theory and oil spill dynamic migration theory,solve the predicted exposure concentration and the predicted ineffective concentration of living species in the leakage area by uncertainty analysis methods,and assess ecological risk of underwater oil pipeline leakage using the ecological risk quotient method to provide a basis for the ecological risk management of oil spills.(2)Comprehensive risk assessment of underwater oil pipelineIdentify the failure risk of the underwater oil pipeline,establish a pipeline risk evaluation index system,combine the fuzzy Petri net theory to build the Petri net model of the underwater oil pipeline,determine the weight of each index of the system through a combination of subjective and objective weighting methods,calculate the confidence and credibility of the indicators at each level using Back-propagation(BP)neural network,and obtain the final comprehensive risk value through fuzzy inference operations.The effectiveness and usability of this method are verified through practical application,which provides a theoretical basis for the comprehensive risk classification of underwater oil pipelines.(3)Study on leakage control and oil spill diffusion of underwater oil pipelinesA physical model of the negative pressure protection system for underwater oil pipelines is established,and a simulation model is constructed to explore the oil spill control effect and oil spill diffusion law of single-point leakage and multi-point leakage.The orthogonal test method is used to design emergency pumping plan,determine different working conditions,and explore the effect of leakage aperture,leakage hole water depth,negative pressure protection level,initial pressure of pipeline on pipeline leakage,time for crude oil to reach the water surface and maximum plume diameter of crude oil.The analysis results provide guidance for the design of relevant parameters of underwater oil pipeline leakage emergency technology(4)Research on emergency strategy methods for underwater oil pipelinesConduct research on the emergency response plan for underwater oil pipeline leakage,determine the emergency response characteristics and implementation principles of the emergency response plan for underwater oil pipeline leakage,improve the emergency process.Develop alternative emergency response plans,build an underwater oil pipeline accident attribute set,analyze the relationship of each attribute using the Best-worst Method(BWM),calculate the total utility of each plan,conduct a comprehensive risk assessment of each plan in combination with the comprehensive risk value of the pipeline,and find the best emergency response plan.