US GoM EPS FPSO. OPERATORS PERSPECTIVE C. Mastrangelo & J. Daniel. FPSO Research Forum - April 25th 2007 Theme Disconnectable FPSOs

Transcription

1 US GoM EPS FPSO OPERATORS PERSPECTIVE C. Mastrangelo & J. Daniel FPSO Research Forum - April 25th 2007 Theme Disconnectable FPSOs

2 TOPICS Operator objectives Safety Regulatory Environment Concept Selection Process FPSO Disconnectable Permanent Moored Internal Turret Design Premise Conclusion

3 OPERATOR OBJECTIVES SAFETY During design, Fabrication, Installation AND Operations: 1. Safety of Life 2. Safety of Environment 3. Safety of Asset Compliance with Local Regulations Minimum Overall Cost On schedule Optimize Production

4 WORLDWIDE FPU FLEET 1Q 2007 FPSO AND SEMI FPU FLEET PETROBRAS PETROBRAS WORLD WIDE IN OPERATION IN OPERATION # OF UNITS PERCENT OF WORLD FLEET # OF UNITS FPSO % SEMI % TLP SPAR FPSO & SEMI TOTAL % TOTAL FLEET % Quest Database 2007

5 SAFETY:ENVIRONMENT EIS RESULTS ON SPILLS MMS EIS 2001 pg.xv Based on the risk assessment, the risk of spills unique to FPSOs operations in the GoM is low risk of oil spills during offloading from the FPSO to the shuttle tanker is similar to that for lightering operations in the GOM, where there is a history of low spill frequency and small spill volumes. NOTE: Petrobras performed more than 3000 offloads in Brazilian waters with no spills

6 SAFETY:ENVIRONMENT EIS RESULTS ON SPILLS OF TOTAL FPSO SYSTEM RISK: SPILL IS 5% Approximately 94.4 percent of the volume of potential FPSO-unique spills is likely to be due to the transfer of oil from the FPSO to the shuttle tanker and from the shuttle tanker transit to shore percent of the volume of potential FPSO-unique spills is likely to be from shuttle tankers near port percent of the volume of potential FPSO-unique spills is likely to be from shuttle tankers in transit to port. 1.8 percent of the volume of potential FPSO-unique spills is likely to be from the transfer of oil from the FPSO to the shuttle tanker. However, this volume is comprised entirely of the smaller spill sizes (<1,000 barrels). 95% OF TOTAL RISK IS SIMILAR TO RISK OF OTHER DEEP WATER FLOATING PRODCUTION UNITS

7 REGS: FPSO REGS FOR US GoM Existing US Regulations are not entirely applicable to FPSOs. Several Operators have considered FPSO production systems, but only the Petrobras operated Cascade / Chinook field FPSO was submitted and the concept approved by regulators. Gaps exist in the concepts accepted by regulators. New concepts have to be justified prior to use in the GoM.

8 REGS: CONCEPTS VIEWED AS NEW TO US GoM For Cascade and Chinook: FPSO Disconnectable Turret FPSO Tandem Offloading Free Standing Hybrid Riser Some Optional New Concepts: Torpedo Piles (Petrobras Patent) Polyester Ropes (First GoM FPSO mooring with Polyester ropes)

9 Cascade Chinook CONCEPT OVERVIEW Cascade /Chinook Non DP-Internal Turret fully moored Disconnectable FPSO Producing from two fields 250 miles from New Orleans Shuttle Vessel FPSO 5 FSHR 4 Production 1 Gas Export line 4 Catenary Umbilicals Tandem Offloading Gas Export Pipeline Gas Export FSHR Dual PIP Production FSHR Flowlines Power Umbilical Boosting Tree Dual Flowlines Pump 4-Slot Manifold Boosting Pump Tree Control Umbilical

10 WHY AN FPSO? Items that drove selection to FPSO: Lack of Infrastructure EWT and EPS function Favorable CAPEX and OPEX Schedule driven project Versatility Reliability More than Adequate Deck Capacity

11 WHY DISCONNECTABLE SYSTEM? Mitigates risk to life and environment. FPSO disconnects and sails out of harm s way. Rapid build up of production if wells available Reduces potential production downtime by preventing storm damage. Capable of leaving for shore for unforeseen maintenance or repairs. Mooring System Design Criteria limit known. (design for known vs. unknown)

12 WHY PERMANENTLY MOORED? Disconnectable Turret / Dynamic Positioning Suitable for limited number of risers. Light mooring system for disconnected buoy Requires design for Emergency Disconnection Disconnectable Turret / Permanently Moored More flexible in number of risers. Permanent mooring system for disconnected buoy. Design for Planned Disconnection. Cascade / Chinook (5 FSHR & 4 umbilicals) DP light mooring 3X2 mooring lines. Non-DP Permanent Mooring 3X3 mooring lines.

13 OPTIONS FOR TURRET PERMANENTLY MOORED Disconnectable system configurations; Internal Turret / Submerged Buoy Turret Moored Submerged Buoy (STL / STP) Riser Turret Mooring (RTM) PAI evaluation shows: Limited difference in features and operations. All have several years operational experience. All are controlled disconnect & reconnect. All connection and disconnection is contained. All are considered suitable for use in the GoM.

14 INTERNAL TURRET / SUBMERGED BUOY Turret Access Structure Swivel Stack (red) Turret Decks Vessel Moonpool Submerged Buoy Mooring Lines Picture courtesy of SOFEC

15 Pictures courtesy of APL TURRET MOORED SUBMERGED BUOY

16 Picture courtesy of SBMAtlantia RISER TURRET MOORING (RTM)

17 WHY INTERNAL TURRET PREFERRED? Turret location adjusted for optimum location to minimize FPSO induced riser motions. (Location must ensure passive weathervaning.) Buoy does not travel through the wave /air interface during disconnection and connection. Reduced riser motions when disconnected, since the turret buoy submerged depth will be below the wave zone. Protected access to the top of turret buoy.

18 DESIGN PREMISE Process plant capable of producing in up to a 5yr Winter storm with a 1 yr Loop/Eddy condition. FPSO, Mooring and Utilities designed for 100yr Winter storm condition. Target: disconnect in <1 hr. at design wave height of 4.5 meters. (Riser excursion limit may govern some disconnects). Time to disconnect and sailing speed must be sufficient to move away from the path of a hurricane that may be born in the GoM.

19 EXAMPLE OF TURRET-BUOY INTERFACE Current Turret / Buoy interface has two (2) valves, a means for crude purge, blind flanges for isolation when buoy is disconnected. Location of Isolation Blind flanges To Closed Drain / Vent Purge Premise: Zero (0) Fluid Spill at Disconnect Fail Safe Actuator

20 POTENTIAL PLANNED DISCONNECT TIME LINE Production Stopped Cascade Chinook No Touch Period Up to 4 hrs. 5 Displace Production Fluids 2 Close Isolation Valve / Drain / Purge 1.5 Add Blinds Isolate Wells & Treat Trees Flush Well Jumpers Flush Subsea Pumps Prep Umbilical Connections Other Turret / Buoy preparations Prepare Vessel Propulsion System, etc. Displace Production Fluids Prep Buoy Connector 0.5 Flood Lower Turret 1.0 Disconnect Buoy Hours Production stopped anytime prior to 0 hrs. Unplanned would not include displacement of fluids.

21 CRITICAL WHAT IF? What if the primary disconnect system fails to disconnect? Safeguards to mitigate will be: Redundant disconnect system. Rigorous maintenance and testing program and design philosophy. On site testing w/o disconnect Appropriate SF in design. Design for Disconnect during Black-out. (Power from Emergency Generator)

22 CONCLUSION Disconnectable FPSOs provide a means to improve protection of life, environment and asset during GoM hurricanes All critical components of a disconnectable FPSO have been successfully proven in operations world wide EPS Disconnectable FPSO Can be considered a Reliable and Efficient Concept for the deep water fields in GoM Flexibility of a disconnectable FPSO facilitates the accommodation of uncertainties such as environment, fluid production, composition and deck loads.

23 US GoM EPS FPSO OPERATORS PERSECTIVE C. Mastrangelo & J. Daniel FPSO Research Forum - April 25th 2007 Theme Disconnectable FPSOs

24 DISCONNECT SIMULATION BUOY DISCONNECT SIMULATION FROM AN FPSO IN A 100 YR WINTER STORM. COURTESY OF DEEPSTAR. PREPARED BY TECHNIP.