A tanker-based Floating Production Storage and Offloading system (FPSO) is an important asset in developing marginal, large and remote offshore oil fields. The FPSO is a floating facility mainly installed near oil and gas production wells to receive, process, store and export hydrocarbons. Most FPSOs consist of a shipshape hull, permanently moored on-site via a free weathervane or fixed heading mooring system. At present, there are nearly 200 FPSO units operating around the world.
Trends
FPSOs have traditionally been used in oil producing regions that lack an established pipeline network (China, Brazil, Indonesia, West Africa, Australia). In the early 70s, FPSOs were developed in small fields (20 - 80 million bbls.) and in regions with mild environments and shallow waters as an intermediate solution to start up of oilfield production. Continuous improvements in mooring systems, fluid swivel technology, and offloading systems have greatly increased the reliability of and confidence in these systems. FPSO technology is now a dedicated solution for both large and small field developments in harsh and deepwater environments.
With the increased presence of FPSOs in remote areas and the lack of a support infrastructure, mobile dry-docking support for FPSOs can be the solution for unit owners or operators. Repair yards can be located far away from the FPSO resulting in significant downtime if the unit is disconnected. Also shutdown of the oil field should be avoided wherever possible, as damage can occur to the reservoir and wells.
FPSO Dry-docking
With the significant presence of FPSOs in remote areas often lacking support infrastructure, Dockwise has developed a completely new service: FPSO dry-docking. With the Dockwise Vanguard, the latest edition to the fleet, Dockwise is well positioned to offer the industry’s first offshore and quayside dry-docking service for Inspection, Repair and Maintenance (IRM) opportunities. As the floating unit is safely secured on the vessel’s deck, dry access to critical items of the floating structure is achieved.
Offshore dry-docking enables FPSOs to operate at different conditional modes.
While dry-docked offshore, the unit remains connected to its mooring and turret system while keeping the riser systems intact and with the possibility of continuing limited production. Furthermore, the FPSO will still be capable to freely weathervane around the turret mooring.
Alternatively, the vessel can also support quayside dry-docking by dry-transporting to a nearby designated facility. In this option, local content is stimulated, transit time is reduced and consequential off-hire and production losses are decreased.
Approval in Principle
Dockwise obtained an Approval in Principle (AiP), for this completely new offshore service from ABS as a result of commissioning a Hazard Identification (HAZID) safety assessment. The assessment took place in the presence of a multidisciplinary team of experts and witnessed by representatives from two major oil companies.
Joint Industry Project
Taking dry-docking innovation further, the company began a Joint Industry Project (JIP). This project will focus on the criteria for the ‘float-on and discharge’ of a floating structure—based on a converted VLCC vessel FPSO—on the Dockwise Vanguard’s deck. Confirmatory model tests in an internationally recognised model basin are included in this phase.
By Hans Leerdam, Sales Manager Offshore Projects, Dockwise.