Deepwater Meets The Shelf.

1. Deepwater Meets The Shelf. Paul Stevenson Regional Manager Fugro Structural Monitoring September 9, 2009

2. Deepwater Meets The Shelf • Production from Deepwater Developments rely on the existing older infrastructure on the Shelf to come to Market. • Expanding development in deepwater will inevitable put more strain on the existing older infrastructure.

3. GOM Pipeline Routing

6. Safeguard Structural Integrity of Shelf Platforms • There is a growing need to further safeguard the structural integrity of the shelf platforms. • This is done by regular inspection on typically 5 year interval but can be longer.

7. Current GOM Inspection Approach • Majority of platforms are on a five year underwater inspection interval alternating • Level II - primarily general visual inspection (GVI) • Level III - GVI and close visual inspection (selected nodes and some FMD Flooded Member Detection) • MMS administers this process following Federal law 30 CFR 250.901 which generally adheres to API RP 2A guidelines • Underwater inspection of platforms is primarily performed by divers

8. What Happens to Production When a Hurricane Comes Through The GOM • Similarly an inspection process is enforced after an event such as a hurricane. • Production is shut-in (stopped at source) • Hurricane Passes • Topside Visual inspection is carried out • Assessment done to establish what further level of inspection is required, and carried out. • Pursuant to 30 CFR 250.919 which generally adheres to API RP 2A guidelines and more recently extracts from API BUL 2HINS • Production is started if deemed safe to do so.

9. Which Platforms Are Selected to be Inspected

10. The Post Hurricane Inspections Approximately 3400 platform Inspections were required and has taken many years to complete Why so long?

11. Mainly Due to Lack of Resources After Hurricanes

12. What Happened To Production

13. What Can we do to Ease The Inspection Burden World Trends to Inspection: • Move away from detailed weld inspection and towards less invasive methods (e.g., FMD) • A stronger focus on the overall Structural integrity • Acceptance that some level of damage can be shown to be permissible • Structural Integrity Response monitoring as an alternative to subsea inspection

14. What is Structural Integrity Response Monitoring Structural Integrity Response Monitoring is considered to be the process whereby: • Response characteristics of a structure are measured (either continuously or at regular intervals) • With a view to comparing the measured characteristics with a previously measured baseline or trend.

15. Structural Response Characteristics Mode Shapes, Natural Frequencies

16. Offshore Fixed Jacket Structural Response Characteristics 1st Torsional Mode Sway Mode 2nd Sway Mode 2nd Torsional Mode

17. How do we Assess the Structural Response Characteristics • Sensors on structure • For an offshore fixed platform it can be something as simple as a vibration sensor • Acquire Structural dynamic data • Perform Structural Analysis • Compare results with model or Trend

18. The Basis to Structural Integrity Monitoring The frequency response of the structure is determined from the stiffness and mass properties of the structure. In the over simplified form: • Single Degree of Freedom Oscillator where k is the stiffness of the ‘spring’ returning the mass, M, to its equilibrium position. On a platform, k is a measure of both jacket and foundation stiffness.

19. How Does Structural Response Monitoring Work? • Change in stiffness leads to a detectable shift in response frequency of the platform. • Structures loaded periodically by wave loading. (Excitation force) • Accelerometers detect movement on topsides. (response to excitation force) • PC collects and processes data to show frequencies of dynamic response of structure.

20. Some Examples of Where Response Measurements Are Used? • One of the oldest systems is installed on the CNR’s (formally Chevron’s) Ninian Southern Platform in the North Sea in 1986. • The most recent Fugro OLM systems : • ExxonMobil Thames field (4 platforms) • Statoil’s Kvitbiorn Platform • Chevron’s Benguela Belize Compliant Tower offshore West Africa (about to be commissioned). • ExxonMobil Thebaud Platform (Sable Island) • CNR’s East Espoir • Pemex AKAL H and C1 (includes shallow gas and seismic monitoring) Other OLM systems previously in the North Sea: Shell’s Goldeneye, Tern A, BP’s Magnus, Forties Alpha and Bravo, Total’s MCP01, Statoil’s Gulfaks, Oseberg A and C, 16/11 E Fugro have performed over 200 of these measurements worldwide

21. Advanced Eigen Analysis Combining the advanced computer structural modeling with the advances in measurement technologies

22. Major Benefits of Response Measurements • To reduce periodic sub-sea structural inspection. • Either by extending the time between regular inspection or by omission after an event. • Instant detection of subsea structural failure after seismic event, storms, hurricanes, impact etc • Allow the operator to focus on damaged platforms. • Reduce the time the structure is at risk to a failed member. • Hence reduce the probability of catastrophic failure. • Assess the effectiveness of a repair to platform • Show that the platform stiffness has returned to an acceptable level • Tune Structural Model, for assessing effect of modifications and damage to the structure. • Risk-based inspection methods can demonstrate the influence of the damage on a structure.

23. Secondary Benefits • It can be used as an alarm system on unmanned platforms in the event of a collision with a vessel. • Where marine growth is a problem the system may show a significant change in structural response. • Ensuring no further degradation in robustness during platform abandonment

24. Case Study of Subsea Structural Failure • 4-legged Jacket • 100 meters of water depth • Long term OLM system • Inverted K configuration

25. North F4 NS B4 NS F4 EW B4 EW F2 NS B2 NS F2 EW B2 EW On-line Detection of Structural Failure • 4-legged Platform with permanent On-Line Structural Integrity Monitoring system onboard

26. Sudden Change in Natural Frequency Sudden change in NS frequency • B4 EW • B2 EW F4 EW F4 NS B4 NS North F2 NS B2 NS NO Change in EW F2 EW Sudden change in Torsional frequency

27. Natural Frequency Change NS1 -2.8% EW1 No Detectable change TOR1 -1.2% Summary of Change

28. Frequency D NS1(%) D EW1(%) D TOR1(%) Observed 2.8 0.0 1.2 Possible brace severance with high probability MD41 2.31 0.57 0.88 MH21 2.46 1.00 1.26 MH41 2.46 1.00 1.26 Possible brace severance but with less probability MB41 1.48 0.19 0.53 MD21 1.76 0.22 0.50 Comparison of Measured With Model Analysis

29. Natural Frequencies After Repair

30. Major Benefits of Response Measurements • To reduce periodic sub-sea structural inspection. • Either by extending the time between regular inspection or by omission after an event. • Instant detection of subsea structural failure after seismic event, storms, hurricanes, impact etc • Allow the operator to focus on damaged platforms. • Reduce the time the structure is at risk to a failed member. • Hence reduce the probability of catastrophic failure. • Assess the effectiveness of a repair to platform • Show that the platform stiffness has returned to an acceptable level • Tune Structural Model, for assessing effect of modifications and damage to the structure.

31. Consideration Consideration should be given to applying this technology to the 40 or so shelf installations that the deepwater production relies on.

32. THE END Thank you