Author_Institution :
Dept. of Civil Eng., Texas A&M Univ., College Station, TX, USA
Abstract :
To reduce large motion responses of a turret-moored Floating, Production, Storage and Offloading (FPSO) unit in harsh environment in deep waters, a thruster-assisted position mooring (POSMOOR) system can be applied. By applying the system, global dynamic responses can be improved in terms of the mooring line/riser top tensions, operational radius of the FPSO, and the top and bottom angle of the production risers. Kalman filtering as an optimum observer and estimator for stochastic disturbances is implemented in the developed control algorithm to filter out wave frequency components. Investigation of the performance of a thruster-assisted turret-moored FPSO was conducted in terms of surge, sway, yaw motions, and tension time series by using a fully coupled hull/mooring/riser dynamic analysis program in time domain. The two cases, motion analysis of an FPSO with thrusters and without thrusters, are extensively compared. The numerical examples illustrate that a thruster-assisted turret-moored FPSO can be an effective solution compared to a conventional turret-moored FPSO for deepwater production.
Keywords :
oceanographic equipment; offshore installations; FPSO operational radius; Kalman filtering; POSMOOR system; control algorithm; coupled dynamic analysis; deep water; global dynamic response; hull/mooring/riser dynamic analysis; mooring line/riser top tension; optimum observer; production riser; stochastic disturbance; surge; sway; tension time series; thruster-assisted position mooring; thruster-assisted turret-moored FPSO; turret-moored Floating Production Storage and Offloading; wave frequency component; yaw motion; Filtering algorithms; Frequency estimation; Kalman filters; Motion analysis; Performance analysis; Production systems; Stochastic processes; Surges; Time series analysis; Water storage;
