Research On The Towing System Safety Of FPSO Based On AQWA

Offshore oil and gas resources are the key development direction of energy mining in the future.Floating Production Storage and Offloading Unit(referred to as FPSO),as the mainstream of offshore oil and gas Production processing,Storage and transportation facilities,it needs to be towed by a high-power tugboat from the port to the operating sea area due to its lack of self-navigation capability.In the process of FPSO towing,because of the influence of wind,wave and flow,yaw and yawing will jeopardize the safety of towing.The crew often take measures according to their experience,which is lack of certain theoretical basis.So this paper uses the hydrodynamic analysis software AQWA to analyze the FPSO towing movement,and explores the influence of wind,wave,flow and towing speed on FPSO towing.First of all,using the DM software in the finite element analysis software ANSYS to establish the hydrodynamic model of FPSO and tugboat,and the hydrodynamic model is meshed by using the default meshing method in AQWA.FPSO and tugboat are connected by nonlinear catenary Hydrodynamic model to compose the hydrodynamic model of the towing system for time-domain simulation.Then,considering the effect of wind and flow load,the time domain simulation experiment of the hydrodynamic model of towed navigation system under different wind,flow and initial towing speed is carried out by using AQWA software based on three-dimensional potential flow theory and green function method.Finally,the tension duration diagram,FPSO longitudinal speed,FPSO yaw distance,FPSO course change and other changes caused by sea conditions are emphatically analyzed,and a risk avoidance operation method is put forward when the towing system meets yaw,yaw and so on.This simulation experiment can accurately reflect the state of motion of the 300,000-ton FPSO towing in a certain extent,the experimental results show that,compared with other wind direction,the upwind and the downstream are more favorable to restrain the deflection and yaw of the towed system,combined with the requirements of the "Guidelines for Towing a Sea",it is suggested that the initial towing speed of the FPSO towing system be 2.5m/s.The conclusion of this paper has a certain reference for the study of the movement law of FPSO towing,and provides a theoretical reference for the actual operation of the sea FPSO towing in distress.