On the Design Considerations of New Offloading Hose Applied on a Turret Moored FPSO

Abstract

Offloading hoses are used to transfer crude oil or liquid petroleum products from a fixed offshore production platform/floating production, storage and offloading (FPSO) unit to shuttle tankers. The hoses are subjected to environmental loads that are mainly waves, current, and vessel motions from both FPSO and the shuttle tanker.

New offloading hoses were planned to be applied in a FPSO in harsh environment, and a design analysis was done in this connection.

Numerical simulations were performed on ultimate limit state (ULS), serviceability limit state (SLS) and accidental limit state (ALS) by using the software RIFLEX [2]. Critical responses such as curvature and axial forces are checked.

The following conditions are checked:

1. Normal operation condition with oil filled hose

2. Connect operation condition, floating gas filled hose

3. Emergency disconnect condition

A SIMA [3] workflow was established to calculate accumulated fatigue damage of all the elements of the offloading hose model.

For the new offloading hose, it is important to have a combined bending-tension loading capacity check. A utilization factor is proposed that possibly may be generalized.

The results show that the specified hose has ample capacity for the considered operating conditions for the shuttle tanker to stay in any position within the 2nd emergency shut down sector (ESD2).