Study On Risk Analysis And Control Of Deep-water Drilling Platform Mooring System

This dissertation is supported by the National Key R&D Program of China “"the sea,the deepwater oil and gas major safety accident risk chain evolution and disaster mechanism and coping mechanisms”Targeted at a large number of mooring system providing deep-water drilling platform with position functioning,This Paper puts forward the deep-water drilling platform mooring system risk assessment index system of risk,coupling risk evolution,simulation for the failure accident,and prediction maximum dynamic tension,and risk control and emergency measures,to guarantee the safe operation of mooring system in the platform operation period.The main research results include:(1)Establishment of risk assessment index system for mooring system of deep-water drilling platformIn view of the complexity and uncertainty deep-water of drilling platform the mooring system,The risk factors of mooring system during service period are identified.summarized and concluded.The DEMATEL method is used to determine the causal transmission relationship between the risk influencing factors.The key factors are found.to identify the key and difficult points of risk prevention and control effectively improve the safety of mooring system,the risk assessment index system is established based on AHP and the security situation of mooring system could be improved.(2)Coupling risk evolution analysis of deep-water drilling platform mooring systemThe Bayesian network based on copulas connect function is used to analysis static probability changes of deep-water drilling platform mooring system,The key factors that cause mooring system failure,network are found out.Considering risk coupling factors,changes of mooring system risk value during working period is determined based on system dynamics,and the key coupling factors are identified.And information feedback is provided for risk prevention during operation period.(3)Failure scenario simulation and tension prediction of mooring systemAiming at the failure of the mooring system of the deep-water drilling platform,the operating conditions and the servival conditions were divided,and the maximum offset and average offset of the platform were analyzed to determine the safety performance of the mooring system.Based on the BP neural network algorithm,a prediction method for the maximum dynamic tension of the mooring system is proposed to predict the maximum dynamic tension of the mooring system under different load incident angle,pre-tension and anchor chain integrity degree.The reliability of the prediction method is verified by the independent repeated experiment method.(4)Risk management of deep-water drilling platform mooring systemthe mooring system failure accident consequence and the probability of consequence is determined based on event tree,safety barrier is put forward based on the decoupling of mooring system security barrier.Considering the effectiveness of risk control decision-making and cost,deep-water drilling platform mooring system risk control decision-making model is established,based on the simulated annealing algorithm,the optimum combination of risk decision;Furthermore,based on the performance analysis of the emergency procedures for the failure of the mooring system based on Petri net,the steady-state probability of the possible states of the emergency procedures for the failure of the mooring system was obtained by combining with the isomorphic Markov model,from which the key steps for optimizing the emergency procedures could be analyzed.