Stabilizing tank to improve the operational window of a W2W gangway connecting a Flotel to a FPSO

Abstract

Currently, offshore operations involve multibody systems composed of two or more units. Thus, these complex scenarios require highly reliable dynamic positioning systems for controlling and tracking motion of the vessels and environmental conditions to ensure safe operation with maximum operational uptime. In these operations, the use of walk-to-work (W2W) passive telescopic gangways has become the norm to facilitate crew transfer.The present work presents an experimental-analytical study to assess benefits of a roll Stabilizing Tank (ST) to enhance the operability of a multibody system composed by a Flotel connected to a FPSO by a gangway. The system was studied using reduced scale models at the wave basin laboratory (LOC) of COPPE/UFRJ considering FPSO alone, FPSO connected to the Flotel, and with and without a ST, focusing on the behavior of the FPSO and gangway.An analytical model to evaluate the ST performance was enhanced and validated with experimental results. The model considered a linear system with its parameters tuned based on FPSO properties. Analytical results showed excellent correlation with experimental data.ST performance is remarkable in reducing motions of both, FPSO and gangway. Therefore, it could reduce the risk of operational downtime and potentially lead to significant savings.