27 November 2007

1. WP8 : D.8.1 Report on Deployment/Recovering Procedure 27 November 2007

2. Dome Design Limitations(as agreed during SENER meeting date 15/10/07) • 12 anchoring points (minimum weight in water 34OT, equipped with block and tackle) • Height of the cover: 50 m • Base diameter of the conic cover: 100 m • Upper diameter of the conic cover: 20 m (to be reduced and adapted to the DI final dimensions) • Mooring lines material: Mixte Vectran/Dyneema 80mm except for Dome boltrope and edge cable • Dome material : pre-tensioned membrane type FERRARI precontraint 1002 FLUOTOP T • Maximum vertical tension : 1000 T (minimum vertical tension into Sener early design)

3. DOME DESIGN

4. Deployment Procedure At this stage, 11 stages have been identified : Phase 1 – Deployment of the Mooring Anchorage Dead weights Phase 2 – Side Derrick and BBI installation Phase 3 – surface Deployment of the Dome and DI Phase 4 – Lowering the Riser Tubes along the guidelines Phase 5 – Surface Deployment of the Buffer Bell Phase 6 – Final upending of the Riser Phase 7 – Anchoring the Dome using Mooring Lines Phase 8–Tightening of the Mooring Lines Phase 9 – Deploying the Dome Phase 10 – Release of the riser assembly from the installation vessel Phase 11 – End of deployment procedure

5. Phase 1 – Deployment of the Mooring Anchorage Dead weights 12 off- deadweight installation

6. Phase 2 – Side Derrick and BBI installation

7. Phase 3 – Dome Tensioning Lines deployment

8. Phase 4 – surface Deployment of the Dome and DI • The Dome is installed on the deck of the Dockwise, the DI is fixed on a mechanical frame • Buoyancies are fixed on the DI and on the Dome bottom end side (upper part). • The bottom end part of the dome is connected to a tug

9. Phase 4 – surface Deployment of the Dome and DI • The Dockwise is ballasted and the dome is pull out the dockwise by the tug. • The dome interface is connected to 2 towing lines from the Side Derrick, towed and positioned under the side derrick • The Tug releases the dome and the bottom end buoyancy is removed. The Dome moves vertically under the side derrick

10. Phase 4 – surface Deployment of the Dome and DI • Deployment of the 6 RTC supporting lines which are first engaged in their associated guide and locking system mounted on the BBI. • Connection of the 6 RTC supporting lines (VECTRAN/DYNEEMA 80mm) to the DI. All this lines are deployed from 6 winches with constant traction. • Passing of the three pre-installed tensioning lines to the Dome interface associated pulleys. • Connection (by ROV) of the three pre-installed tensioning lines to the bottom end of the Dome

11. Phase 4 – surface Deployment of the Dome and DI • Removal of upper buoyancies, resumption and setting of the tension in the anchoring lines at the specified tension. Then the dome is lift up to have the DI at the RTC connection chamber level

12. Phase 5 – Lowering the Riser Tubes along the guidelines • RTC assembled progressively on side derrick (50 m joints maximum) • Descent of the DI/Dome/RTC assembly controlled by winches • Tension controlled by the three tensioning lines

13. Phase 5 – Lowering the Riser Tubes along the guidelines • Then the RTC sections are assembled successively and equipped with the associated steel rings. The 6 supporting lines are passed trough the steel ring in the associated dedicated hole. Steel ring RTC supporting lines

14. Phase 5 – Lowering the Riser Tubes along the guidelines • So the DI/Dome/RTC assembly is lowered progressively up to have the DI at level above the sea bottom corresponding at its final deployment elevation (200m) + the Buffer Bell height + 50m of open water). • Descent speed velocity is control by the winches, and visually controlled by the ROV during the whole process. Tension in the RTC/DI/Dome assembly is control by the three tensioning lines. • When the RTC is fully assembly, the length of last riser tube section is adapted as required to have a length passing trough the BBI and which will be insert in the BB at a later stage. • Then, the first 6 riser tensioning lines are locked onto the BBI and the extra lengths are cut. • The four BBI tensioning lines support the total load of the system and allow controlling the tension of the system..

15. Phase 6 – Surface Deployment of the Buffer Bell

16. Phase 7 – Final upending of the Riser • The Riser Assembly and the Buffer Bell are slowly lowered down up to the predefined depth required to unfold the dome. The lowering of the dome and of the RTC/Dome assembly is controlled by the combined actions of the winches of upper supporting lines and Dome tensioning lines. • Slack in the RTC guide lines is taken away by the associated winches

17. Phase 8 – Anchoring the Dome using Mooring Lines • The moorings have already their mooring lines coiled and fixed onto them. The extremity of the mooring line is equipped with ROV hook and with a monkey fist, which is maintained into floatation a few meters above the seabed. • The ROV grabs the monkey fist and pull out the mooring line. • The ROV returns to the Dome, and connects the mooring line to the dome appropriate shackle with the ROV hook • The ROV repeats hooking operation with all of the mooring line, following a circular motion, until all of the mooring lines are connected to the dome

18. Phase 9–Tightening of the Mooring Lines • The ROV supervises the whole operation. • Before giving the order of releasing the soft lifting bags, the senior officer in charge of the project has to make sure that no unnecessary surface traffic is evolving within the firing area, and is outside a delimitated zone, to avoid the accidental surge of one or more lifting bags that would have been accidentally freed from their mooring lines. • ROV should be standing at a reasonable distance, and below the lifting bags trajectory, making sure its umbilical is not tangled with either the lifting devices or mooring lines. The best would be that it rests inside its hosting cage, away from any trouble. • Once the area is cleared, the order of firing is given, and transmitted via ultrasonic devices to the explosive units. • All of the lifting bags should be release at the same time.

19. Phase 10 – Deploying the Dome • The ROV supervises the whole operation. • ROV should be standing at a reasonable distance, outside the dome deployment area and below the lifting bags trajectory, making sure its umbilical is not tangled with either the lifting devices or mooring lines. The best would be that it rests inside its hosting cage, away from any trouble. • Once the area is cleared, the order of firing is given, and transmitted via ultrasonic devices to the explosive units. • All of the attachment devices of the dome should be release at the same time. • Visual inspection by the ROV of the entire dome assembly

20. Phase 11 – Release of the riser assembly from the installation vessel • The three tensioning lines are locked onto the Dome interface • The Buffer Bell is de-ballasted in order to have the final vertical tension into the Riser assembly. As the BB is de-ballasted parallel, the tension is released into the three tensioning line • The Buffer Bell supporting line are disconnected from the BB • The BBI supporting line are disconnected from the BBI (ROV operation) • The extra length of the tensioning line is cut, leaving at least one meter of cable length below the cut for safety reason. • At the end of each cable, a conic blocking device should be set as an ultimate barrier against sliding away of the Dome inreface.