Numerical investigation on the multi-body hydrodynamic interactions under Caspian Sea environmental conditions

Abstract

Floating production storage and offloading (FPSO) platforms are among the most important platforms in the offshore oil and gas industry. These platforms are generally anchored to the seabed through mooring lines. Usually, the FPSO and the oil tanker are nearby before starting the offloading operation. In this research, the hydrodynamic interactions between a turret-moored FPSO and shuttle tanker were examined using the boundary element method for coupled time-domain dynamic analyses. To apply the sea conditions, the environmental conditions of the Caspian Sea were considered. In this regard, considering the values of hydrodynamic forces on the shuttle tanker, the main purpose of this study was to evaluate the most appropriate vertical position of the shuttle tanker in the vicinity of FPSO. Therefore, 19 vertical center-to-center distances with steps of 20 m (from 80 m to 440 m) were considered between the two vessels. A comprehensive assessment of the dynamic responses of the two floating vessels was then conducted at different angular positions of the shuttle tanker relative to the FPSO. The numerical results indicated that the minimum hydrodynamic force was applied to the shuttle tanker for the distance of 400 m between the centers of the vessels. Also, the 60-degree position of the shuttle tanker relative to the FPSO within a 400-m radius was the most critical position in terms of hydrodynamic forces on the shuttle tanker.