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Veselis tph presentation - jan 2013

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Veselis tph presentation - jan 2013

  1. 1. First Permanent Polyester Prelay on the Seabed in Gulf of Mexico Todd Veselis
  2. 2. Objective• History of polyester on the seabed• Discuss of why we took this approach for Mirage – Advantages – Concerns?• Review the polyester prelay approval process• Review the test plan and results
  3. 3. Project Overview• Field: Mirage (MC-941) /Telemark (AT-63)• Owner: ATP Oil and Gas Corporation• Water Depth: 4,000 ft• Hull Type: Deep Draft Floating Platform (DDFP) – MinDOC3• Installation: 2009
  4. 4. History of Laying Polyester on Seabed • Industry testing – late 1990’s – Came as a result of industries work w/polyester – Various JIPs – Lab tests • Inadvertent contact during – Installation – Service • MODU moorings – Began in 2007 – Field trials – Industry experience
  5. 5. NTL 2009-G03• Issued in Jan 2009 by BOEM/BSEE• Provides guidelines for permanent and MODU moorings• Establishes conditions for presetting moorings on the seabed including: – Use of ropes with proven filter barrier – Following recommendations in APR RP 2SM – Site survey – Rope inspection criteria
  6. 6. Advantages to Prelaying Polyester on Seabed • Timing – Allows mooring to be set off critical path and at any time – Allows for changes in hull sail away/installation • Installation – Eliminates need for handling surface/submersible buoys – Eliminates risk of collision/loss of buoy – Allows all polyester to be handed during single campaign • Hookup – Eliminates the need to install polyester during hookup – Increased hookup efficiency – Increased flexibility
  7. 7. Approval Process• Process was somewhat undefined because: – First permanent mooring application where polyester was intentionally laid on seabed• Goal was to: – Demonstrate, through testing, that seabed contact would not have any adverse affects
  8. 8. Approval Process• Satisfy requirements of NTL 2009-G03• Submission of test plan to BOEM/BSEE (formally MMS) for approval – Field test – Subrope testing – Lab testing• Submission of test results to BOEM/BSEE
  9. 9. Field Test• Lowered two test sections onto seabed using AHTS (Anchor Handling Tug Supply) vessel• Performed two drag tests with inserts, each a minimum of 5 min with 5 min in between• Left inserts on seabed for 24 hrs• Recovered inserts to surface
  10. 10. Subrope Testing• Modulus testing – 10th cycle (10% - 50%) – EA/MBL (Stiffness/Min. Break Load)• Break testing – Four control samples – (C) – Four insert samples – (I)• Fatigue testing – 80,000 cycles – Load range – 15%-45% – Sample consisted of 3 full scale subropes
  11. 11. Subrope Testing – Results• Control and insert samples average break strength and modulus were within 1% of each other• Sample survived 80,000 cycle fatigue test without issue
  12. 12. Subrope Testing – Results Breaking Strength Modulus 10th Cycle 10- Sample (kips) 50% (EA / MBL) C.1 383.8 14.7 C.2 411.0 15.3 C.3 398.6 14.3 C.4 419.9 14.8 I.1 417.3 14.2 I.2 402.9 15.5 I.3 381.8 14.9 I.4 399.2 15.1Mean Control Sub-ropes 403.3 14.8 (C.1-4) Mean Insert Sub-ropes 400.3 14.9 (I.1-4)
  13. 13. Lab Testing• Inspection performed on both control and sample yarns• Inspection included: – Visual Inspection – Fiber Testing – Yarn Analysis – Tenacity – Strength – SEM (Scanning Electron Microscope) Photographs
  14. 14. Lab Testing Results• No significant difference in: – Break strength – Modulus – Wet yarn on yarn abrasion – Visual appearance• Yarn from both samples looked new• In very rare cases trace particles were found in outer core yarns
  15. 15. Conclusion• Testing demonstrated that: – Soil filter was effective – Contact with the seafloor had no adverse affects on the polyester• For Mirage, prelaying on the seabed: – Saved time during hookup – Reduced risk
  16. 16. Contact Information Todd Veselis InterMoorEmail: todd.veselis@intermoor.com Phone Number: 832-399-5018

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