Simulation Study On The Evacuation Of Personnel Under The Fire Scenario Of Offshore Platform

Offshore platform is the infrastructure of offshore oil and gas exploitation.Due to the harsh marine environment,narrow platform space complicated structure,highly dense equipment and sufficient combustibles,it is easy for the fire occure on the offshore platform.Offshore platform fires have the characteristics of rapid development and difficulty in fighting and rescue,which poses a great threat to the safety of personnel.Since the personnel on the offshore platform are distributed throughout the platform,it is difficult to quickly reach a safe location during evacuation,which makes the personnel vulnerable to the impact of fire and leads to failure in escape.It is of great significance for emergency decision-making in the fire on offshore platforms to research the probability of fire accidents on offshore platform,the failure of evacuation of personnel and quantitatively analyze the impact of fire on personnel under fire scenarios on offshore platforms.Taking an offshore platform in the South Sea of China as the research object and combining the natural science foundation of Shandong Province-General Project"Research on Fire Emergency Decision-Making for Offshore Platform Based on Virtual Simulation Technology and Dynamic Risk Assessment"（ZX20190048）,probabilistic risk analysis and quantitative research on fire impacts are carried out on fire scenarios of offshore platforms.The main research is as follows:（1）Statistical analysis of fire on offshore platformsAccording to the statistical analysis of 627 offshore platform accidents from 1995 to 2000,it is found that fire accidents account for the largest proportion of all offshore platform accidents.According to the statistics of 101 fire accidents,it is concluded that the main causes of fire are equipment failure and human error,and it is found that the most common ignition source is the hot surface of equipment.（2）Bow-tie analysis of fire and evacuation accident scenarios on offshore platformsThe fuzzy Bow-tie method is used to calculate the probability of fire on offshore platform and its evacuation process.The offshore platform fire fault tree is constructed and the event tree is built reference to the offshore personnel evacuation process.A Bow-tie model is built based on the fault tree and event tree,the probability of basic events and key events is solved by the using the fuzzy set theory and the risks of offshore platform fires and evacuation is quantitatively analyzed.The key events in the evacuation process are ranked according to the probability of accident:personnel movement failure,platform evacuation failure,assembly failure,and rescue failure.（3）Simulation of fire consequence with different oil pool diameters and wind speedsConsidering the impact of wind speed change on the fire development,the offshore platform fire model is built by using FDS.Referring to the impact of people of the temperature,visibility,concentration of CO,CO₂,O₂,smoke layer height and other factors,a set of risk evaluation indexes is built.Combining with the environmental conditions of the area where the platform is located,10 fire conditions are designed for simulation,and the results show that:The lower deck and the middle deck are more severely affected by the fire,while the upper deck is less affected;Compared with other factors,the visibility and smoke layer height change faster.（4）Traffic congestion and safety analysis in evacuation process of offshore platformThe evacuation dynamics software Pathfinder is used to construct the evacuation model.Considering the two movement modes of the people,the congestion phenomenon during the evacuation process is analyzed through the changes of the personnel density,the flow of people on the stairway,and the level of service the stairway during the evacuation process.The results show that in the running mode,the effect of congestion is small and the efficiency of evacuation is higher.（5）Construction of evacuation simulation system for offshore platform under fireUnity3D engine is used to build the simulation system of personnel evacuation under fire scenes.Importing the isosurface data file simulated by FDS into the Unity3D engine and using the Unity Shader Lab component to render it to realize the visualization of the fire scene;Giving the isosurface collision attribute,so that the Agent in Unity3D can perceive the impact of fire environment through the collision detection.The maximum exposure time model is used to construct a human life loss model,and the fire parameters perceived by the Agent are input into the model to quantify the impact on human life and health.The usability of the system is verified by comparing with the simulation results of Pathfinder and FDS+EVAC.The results show that the dead people are distributed in the middle deck and lower deck which are close to the fire source and high temperature has a greater impact on casualties.