Research on dynamic risk assessment method for Christmas tree systems on offshore platforms with real-time updated evidence
The offshore platform Christmas tree system is one of the important pieces of equipment for oil and gas production.To ensure safe and efficient production of oil and gas wells and address the issue of real-time evidence updating in the dynamic risk assessment of the Christmas tree system,a dynamic risk assessment method for offshore platform Christmas tree production based on dynamic Bayesian networks,physical element theory,and evidence theory is proposed.Firstly,the failure mode and state transition model were determined based on the structure and failure rate of the Christmas tree system,and a dynamic Bayesian network structure and parameter model were established.Then,the consequences of various failure modes were quantitatively analyzed using physical element theory and expert experience,and the risk interval of each key component of the Christmas tree system was obtained by considering the probability of risk and the quantified consequence values.Finally,evidence theory was used to transform newly added evidence into a risk interval and combine it with the theoretical value to calculate the risk interval of the Christmas tree system.Risks were predicted based on the established dynamic Bayesian network.An empirical study was conducted on a certain Christmas tree,and the results show that the Christmas tree body is the key component with the most severe consequences,and the main failure modes of various valves in the Christmas tree system are switch failure and valve leakage.With the increase of new evidence,the uncertainty of risk interval decreases.The risks of the tubing wing valve,throttle valve,and surface safety valve in the Christmas tree system are relatively high,and corresponding preventive measures need to be taken to ensure the safe and reliable operation of the Christmas tree system.
safety engineeringrisk assessmentChristmas tree systems on offshore platformsDynamic Bayesian Network(DBN)matter-element theoryevidence fusion