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FPSO Redeployment

  1. Design Considerations for FPSO Redeployment – FPSO Congress 2015 Presentation by - Noel Denton
  2. Background to FPSO Redeployment Challenges of FPSO Redeployment Case Study: Front Puffin Case Study: OSX-1 Case Study: Berantai Conclusions Design Considerations for FPSO Redeployment Contents
  3. Background FPSO Redeployment History FPSO East Fortune (Songa Floating Production) conversion to FPSO Berantai (Petrofac Floating Production) • FPSOs offered the industry a technology that could provide a large processing facility with the ability to redeploy • Redeployments have been achieved successfully on a number of occasions in the industry – but it is not always as straightforward as it seems. • There have been 24 redeployments in the last 10 years • Some vessels have been redeployed on multiple occasions • The range of modifications required can be from minimal to extensive such as new topsides and jumboisation of the hull – this requires a lot of careful planning at the start.
  4. Background of FPSO Redeployment From Crystal Sea (Crystal Production), to BW Carmen (BWO) to BW Athena (BWO)
  5. Background of FPSO Redeployment Why an FPSO? • Potentially fastest route to first oil when compared to other equivalent topsides substructure options • Leased option can improve project economics especially for shorter field lifes • Short field life or uncertain reservoir performance makes leasing with extension options attractive • Lack of infrastructure for export and flexibility to deliver product to the global market • Offers the option to be disconnectable in regions with adverse weather • Readily deployable in a range of water depths from shallow to deepwater • Large topsides carrying capacity • Storage available to mitigate process interruptions
  6. Background of FPSO Redeployment Why redeploy? • Shortened project execution schedule leading to earlier first oil • Potential reduced day-rate when compared to fresh conversion / new build • Proven service history
  7. Challenges for FPSO Redeployment Technical Hull • Global strength and fatigue needs to be checked including stability check if new modules are added; • Steel replacement for life extension and coating repairs; • Change of class / flag / regulatory regime can require modifications to the hull and accommodation which are difficult to estimate until arrival at the shipyard. Mooring • Is the mooring type applicable for the new deployment: • Is the water depth suitable for a disconnectable mooring? • Does the FPSO require to be spread moored or turret moored? • Is the turret suitable: • Are the loads similar? • Are the number of risers and umbilicals similar?
  8. Challenges for FPSO Redeployment Technical Topsides: • It is more than just checking the name plate capacities! • Gas compression systems are sensitive to composition and changes to pressure ratios; • Material selection should be verified based on CO2 and H2S content. It is also important to establish a baseline condition for the vessels and piping to establish remaining life; • Flare system design; • Flow limitation through the turret and swivel paths including erosion issues for sand content; • Water cut; • Is it a heavy crude? • Increased power requirements • Increased heat load • Tertiary treatment required
  9. Challenges for FPSO Redeployment Technical Topsides: • Change in regulatory requirements: • Are there additional requirements for the topsides? • Is a safety case required?
  10. Case Studies
  11. FPSO Front Puffin Background • The FP was converted in 2007 from Shuttle Tanker to FPSO and then deployed as an FPSO for Puffin field • FPSO Front Puffin was deployed at AC/P22 Block North of Western Australia • FPSO Front Puffin is now to be redeployed to the Aje Field in West Africa • The mooring and hull require minimal modification despite moving from Australia to West Africa • The topsides require additional modules to fulfill the field requirements Case Study FPSO Front Puffin (Rubicon Offshore International)
  12. FPSO Front Puffin Modifications • Replacement of existing gas lift compressor package with new package. • Addition of gas dehydration package • Addition of fiscal metering skid • Addition of subsea chemical injection package • Upgrade of methanol injection package • Addition of subsea master control system • Addition of subsea hydraulic power unit • Upgrade of control system for new packages • Upgrade of power distribution system for new packages • Integration piping • FEED study for pre-engineering for future upgrade scope (gas fuelled power generation) Case Study FPSO Front Puffin (Rubicon Offshore International)
  13. FPSO Front Puffin Challenges and solutions • Gap analysis – At the earliest opportunity conduct a gap analysis to quantify the scope and identify any major hurdles. • Gas compression – replace existing units and add a gas dehydration unit • Change in Fiscal Regime – New gas metering required • Congested deck area requiring careful analysis of support locations and tie-in points – utilisation of 3D modelling to ensure efficient implementation • Multiple contractors – Successful use of the integrated team approach to minimise interface issues • Upgrade of existing facility – Close liaison with operations to ensure as built information is robust when being implements into new configuration Case Study FPSO Front Puffin (Rubicon Offshore International)
  14. OSX-1 FPSO Background Case Study FPSO: OSX-1 FPSO Location: Brazil Client: Keppel / BW Offshore Upgrade of the new-build Nexus 1 FPSO to make it suitable for the OSX Waimea heavy oil field (API 17.6) offshore Brazil Involves 7 new modules including • Inlet Manifold • Crude Heating • Water Injection • Fuel Gas Compression • Power Module
  15. OSX-1 FPSO Background • The Nexus-1 FPSO was developed as a harsh environment generic FPSO • Although it was never deployed, it can be seen that even a generic FPSO required extensive upgrade to make it suitable for its eventual deployment • The Nexus-1 FPSO became the OSX-1 • The heavy oil characteristics meant that extensive heating and tertiary treatment were required to achieve the crude specification Case Study
  16. everything in pink is a change OSX-1 FPSO • Extensive modification was required to the topsides Modifications Case Study
  17. OSX-1 FPSO Tertiary Treatment / Options for Treatment for Heavy Oil • VIEC Internals – These can be retrofitted to existing separators to improve separation of oil and water • Compact Electrostatic Coalescer – This can be used upstream of existing separation to promote increased droplet sizes to improve separation • Modified Internals for the Electrostatic Coalescer – This can be used to increase the allowable water cut and/or to improve separation • Centrifuge – An established technology for treatment of heavy oils / tar Case Study
  18. FPSO: Berantai Location: Malaysia Client: Keppel / Petrofac / Petronas Upgrade of the East Fortune FPSO to make it suitable for Berantai Field in Malaysia Includes 9 new modules (approximately 5000 Te)upgrading Berantai FPSO Background
  19. Berantai FPSO Background • FPSO Berantai was developed from the FPSO East Fortune • FPSO East Fortune was a generic FPSO which was never deployed • As with OSX-1 although it was a generic FPSO it required extensive modification for its eventual deployment • The historic difficulty of successfully employing the generic FPSO concept demonstrates the fundamental difficulty of matching the topsides to the field (other economic factors also impacted the success of the concept) • The versatility of load bearing capacity of the ship-shaped hull is demonstrated by the dramatic increase in the topsides between the two concepts. Case Study FPSO East Fortune (Songa Floating Production) conversion to FPSO Berantai (Petrofac Floating Production)
  20. Berantai FPSO Before and After FPSO before upgrade FPSO after upgrade
  21. FPSO Redeployment Conclusions • The FPSO remains an attractive option for field development due to its inherent ability to be redeployed • When considering redeployment the entire FPSO needs to be examined through thorough gap analysis – mooring, risers, hull, marine systems, safety systems, accommodation and topsides. • Although redeployment is not necessarily straightforward with careful planning and robust engineering it can be achieved successfully
  22. Noel Denton T 96271998