Research On Risk Identification Of Mooring System Based On FPSO Motion Response Analysis

China’s sea area is rich in oil and gas resources.FPSO(floating production storage and discharge unit)integrates various functions such as processing,production,oil storage and external transportation.It is an important strategic equipment for offshore oil development,and it has been used extensively in oil and gas fields in Bohai Sea and the South China Sea.Moreover,with the advancement of technology and the continuous increase in oil production,the FPSO tonnage is also increasing,which puts more stringent requirements on the safety of FPSO production.With the continuous development of sensor technology,real-time monitoring of offshore oil production platforms has increased in domestic and overseas but various monitoring of single-point mooring FPSO is still rare in China.Based on the FPSO motion response analysis,the paper establishes a huge motion response database,and then finds the risk identification point of the mooring system,and installs monitoring instruments to monitor it in real time to ensure the safe operation of the FPSO.Firstly,SESAM is used to establish a finite element model for a tower-type yoke arm single point mooring system FPSO in China.Apply different conditions and loads to get the FPSO hydrodynamic parameters of the frequency domain calculation and coupled dynamic analysis results of the time domain calculation with the mooring system.The calculation and analysis results provide the basis for the strength check of the MSS(mooring support structure),the mooring leg and the YOKE arm structure.Then,ANSYS is used to establish a finite element model of the mooring system,and check the mooring system strength.According to the strength check results of the MSS,mooring leg and YOKE arm,the risk points of the mooring system are identified.Classify risk levels and carry out environmental load risk identification,hull and mooring system horizontal distance(collision)risk identification,hull draft(bottoming)risk identification,mooring load risk identification,mooring system corner risk identification,mooring system inclination risk identification,etc.And according to the risk identification points to install monitoring instruments,develop an overall health monitoring program to achieve real-time monitoring of FPSO.The research content helps to improve the integrity management level of the single-point mooring system,and grasp the FPSO motion state and the force of the single-point mooring system components in real time,ensuring the safe and stable operation of the FPSO and the single-point mooring system and providing technical support for management and optimization of the FPSO.