Risk Assessment And Control Strategy For Individual Evacuation,Escape,Rescue On Offshore Platforms

The offshore oil and gas industry is worldwide known for its greatest risks.As main production facilities in the exploration and exploitation of oil & gas,the offshore platforms are prone to accidents with a high probability for harsh working environment.At the time of accidents,EER,short for "evacuation,escape,rescue",often plays a vital role in transferring personnel and safeguarding the lives.Therefore,in order to meet the demand of enhancing emergency action levels,depending on the 2012 State Administration of Work Safety Key Control Technology Projects for Work Safety Major Accidents “Risk management and emergency technology for deepwater drilling in the South China Sea”(NO2012-507)and Fundamental Research Funds for the Central Universities(NO14CX06130A),the paper chooses the EER operations on offshore platforms as study subject,carrying out the relevant research about risk assessment and control.1 Risk-influencing factors analysis of EER operations on offshore platformsStatistical analysis on accidents during the EER process showed that fire or explosion,overturn and tropical cyclone are the main inducements to EER operations on offshore platforms.Considering diversity of choices,a multiple attribute decision making model of EER ways is made based on TOPSIS(Technique for order preference by similarity to ideal solution)and validated using a project instance.Meanwhile the model of EER operations with seven subphases on offshore platforms is built for guaranteeing personnel safety.Risk-influencing factors,including human,facility,environment and management are identified systematically by using EER Hazard and Operability Analysis.Based on the results,using the method of DEMATEL(Decision making trial and evaluation laboratory),logical relationship between factors is showed by a relation path graph in different stages,plotted following calculating threshold value according to the variance and mean.2 Human reliability analysis of EER operations on offshore platformsBased on fuzzy math and CREAM(Cognitive reliability and error analysis method),a human reliability analysis model of EER on offshore platforms is made through hierarchical task analysis module,common performance conditions module,fuzzy control modes,the failure of cognitive actions and fuzzy calculation rules.Based on accident investigations and accident cases,human reliability quantitative analysis is made especially for three main scenes which caused EER operations.Some results can be got through the above assessment as the individual failure probability,the focus of steps,failure mode,etc.3 Accident coupling risk analysis of EER operations on offshore platformsOn the basis of engineering data,the numerical model of offshore platform EER under fire scene is built with the judgment criteria of fire risk and evacuation risk.Based on the FDS simulation results,the variation laws of evaluation indexes such as temperature,thermal radiation,visibility,the concentration of toxic gas are analyzed in details and the hazardous area of fire accident is identified.In addition,available safety egress time of emergency exits and the minimum safety radius for workers in emergency evacuation are suggested.Furthermore,compared with the evacuation simulation results under normal condition,quantitative analysis of coupling risk under fire accident condition is carried out based on FDS+EVAC.In order to evaluate the dynamic risk of evacuation paths,a topological model of evacuation routes on offshore platform is made by applying some methods in graph theory.The reliability results of the model analysis show that there is a relatively close relationship among different working areas and paths network would crash theoretically if more than 51.4% nodes lose efficacy.The scheme of ideally shortest paths to different destination in different areas is suggested based on the Dijkstra algorithm.At the same time a prioritization scheme is provided under overcrowding and fire accident.4 Safety barriers analysis and optimization of EER operations on offshore platformsSafety barriers are proposed as control strategies about EER operations.Functional classification and ways of barriers action are analyzed in order to locate the weak point.And a framework of offshore platform staff position management system is built as an optimization plan,integrated with some information techniques such as radio frequency identification devices,ZigBee,virtual reality,etc.The system collects the personnel positioning function,evacuation of real-time simulation functions and path optimization function,which can contribute to the decline of casualty's probability.