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+4 votes

FPSO Tandem Offloading Pros & Cons

asked Feb 25, 2014 in Offshore-Upstream by judyp (2,700 points)
What are the advantages and disadvantages of FPSO Tandem Offloading?

1 Answer

+2 votes
answered Mar 24, 2014 by Normandy (21,120 points) | selected Mar 24, 2014 by judyp
Best answer

Tandem Offloading Benefits

  • Minor oil spills or fire from the shuttle tanker will not interfere with or endanger the FPSO's operations since the tanker is always downstream of the immediate current and wind, not just prevailing

  • Simplify naval operations in approach, residence, decommission, abandonment, and relocation

  • The architecture of flexible hose allows for large operating envelope, not only dynamic but also static which corresponds to the positioning envelope of the vessels

  • No swivel parts - minimizes the potential leakage by avoiding mechanical pieces on the fluid path

  • Minor efforts involved in removal of the offloading equipment since it is a part of the vessel

Tandem Offloading Cons

  • The captains of the export tankers are all different, some maybe inexperienced with tandem offloading, tanker approach, potential changing sea conditions

  • Tug costs for tandem offloading are significantly higher than for CALM buoy. Although it makes sense for a short field life; for a long field life (7+ years) a buoy would be more appropriate

  • Loading times are shorter (due to weather) and it requires more attention from the FPSO crew diverting them from their production tasks so tandem offloading is not very efficient

  • Since FPSO is tethered to the TLP with multiple high tension capacity hoses, it is raising the criticality of hawser load limits and safety release