Study On Quantitative Risk Assessment Of FPSO Leakage And Explosion Disasters

FPSO(Floating Production Storage and Offloading)is an offshore floating production and storage tanker.It is an offshore floating storage and offloading device integrating production,storage and offloading.It is called offshore oil factory.However,the upper module of FPSO is densely populated with complex structures and is prone to oil and gas leaks.The gas explosion on FPSO will cause significant damage to people,environment and assets.This article conducts a quantitative risk assessment study on FPSO leakage and explosion disasters.The main research contents are as follows:(1)The quantitative risk assessment methodologies for FPSO gas leakage and explosion disasters are proposed and the key technologies are analyzed.(2)The leakage mechanism of flammable gas and parameter sensitivity are studied.The gas leakage mechanism and theoretical model are analyzed.The gas leakage simulation method using FLACS is verified.Based on FLACS,the leakage diffusion model is established to study the leakage mechanism and diffusion process.The parameter sensitivity to the equivalent gas cloud is analyzed.A method for determining the position of the equivalent gas cloud is proposed.(3)Explosion mechanism and parameter sensitivity of overpressures are studied.The basic types and physical processes of gas explosions are analyzed;The effectiveness of FLACS explosion simulations are verified by MERGE test;FPSO explosion model is established based on FLACS to study the flame propagation and gas explosion laws in the presence of obstacles.And parameter sensitivity to affect explosion overpressure is analyzed.Finally,a method for determining the explosion scenario based on the leak scenario is proposed.(4)The dynamic response of the process deck structure under the explosion overpressure is studied.The nonlinear problems in dynamic structural analysis and commonly used analysis methods are discussed.The numerical model based on nonlinear finite element method is established;the dynamic response process of deck structures is analyzed;and the impact of peak loads and structural forms on deck dynamic response are explored.(5)Case study of quantitative risk assessment.A method for quantitatively generating leakage scenarios is presented.Based on the real structure of an FPSO,60 leakage scenarios are generated based on sampling of five influencing factors.Explosion probability calculations and consequences calculations are performed on 60 scenarios respectively;explosion overshoot curves and overpressure-probability combinations are used.Values are presented in two forms for risk results,and personnel and structures risks are evaluated.