Edit this text for your title

1. Edit this text for your title Planer for MEK 4450 Marine operasjoner Edit this text for your sub-title Presenter name, location, date etc. Kværner ASA, June 2011

2. Safety moment

3. Installation of flexibles and cables Typical products Rigid pipes Flexible pipes Cable and umbilicals Configurations at platform Installation aids Installation and installation analyzes Installation of end terminations Regular lay Special challenges: shallow water, deep water, slopes, turns etc Waiting on weather

4. Typisk produktinndeling Pipe Rigid Flexible Cable Electric Umbilicals Beam theory. Axial load Compression Bedning moment Courtesy: Bredero Shaw Courtesy: NKT Flexibles Courtesy: Nexans Courtesy: Nexans

5. Rigid pipe Large diamter Heavy High laying tension High bending radius Large deck space Expensive equipment Plastic deformations acceptable Rightning before over boarding Avoid repeated plastic bending! Thermal isolation (wax formation) Concrete layers (gas pipes) Courtesy: Bredero Shaw

6. Flexible pipes Low elastic bending radius Less expensive laying vessels / equipment More competition Separate layers for Axial load Outer pressure Inner pressure Courtesy: NKT Flexibles

7. Cables Power cables and umbilicals Small radius, bending radius, unit weight Less expensive vessels / equipments High density Huge loads on a fully loaded vessel Structural capacity and vessel stability Combined functionality No plastic bending Courtesy: Nexans

8. Theory slide. Installation aids Flexible products are installed with various types of vessels equipped with means / tools for storage and controlled over boarding of the products. Typically, the installation of rigid steel pipes requires bigger and more expensive vessels due to the huge space and holding capacities required during deck handling and installation. In the following slides some typical examples are given. The first example show a laying vessels for electrical cables, where the cable are stored on a horizontal turntable. A horizontal caterpillar is used, where a tensioner will carry the weight of the product during overboarding. The vertical U- shaped unit at the side of the vessel is called a chute and prevent damages to the product when it goes into the sea. We notice that the vessel is equipped with huge crane and a large open deck space. This means that the vessel may be used for other types of marine operations, like subsea lifting. Separate slides display the installation equipment used by this vessel. We notice the belt with the orange pads forming the tensioner. The pads are pushed toward the cable to ensure sufficient friction. By running the belt the cable may be pulled in or out. The other slide shows the chute. The next slide shows an alternative configurations, where the product are routed via a vertical or almost vertical laying tower during over boarding. The tensioner are mountd in the laying tower. The third slide shows a vessels for pipe lay. Steel pipes are spooled on the enormous vertical drum in the centre of the vessel. The hold-back force is taken by the drum itself. In the stern part there are equipments for straightening out the pipes if there have been plastic deformations and a laying ramp for smooth transition of the product to the sea. The last two slides shows two other options, particularly useful for laying of rigid pipes. The first case shows a vessel where the new pipe sections are welded to the pipe continuously during over boarding and laying. The huge stinger in the stern of the vessel will prevent critical over bending of the product,- plastic deformation is no longer acceptable as the product are going into the sea and there are no means for straightening it out again. The last slide displays another alternative, where huge cranes are lifting pipe segments into a vertical “J-lay tower”. Here the segments are welded to the pipe being laid, again continuously during laying. This solution is particularily popular in deep water, while the previous solution may be more suited in shallow water.

9. Typical installation vessels Installation vessel with horizontal caterpillar og chute Installation vessel with lay tower Pipe lay vessel with reel and lay ramp Pipe lay vessel with stinger Semi-submersible Anchor vessel DP vessel Pipe lay vessel with J-lay tower

10. Installation vessel with horizontal caterpillar and chute Aker Connector

11. Tensioner / Caterpillar Used to pay in / out product, and maintain tension Belts with pads pushed toward the product. Friction Sufficient force to Pull in and overcome friction over chute Keep cable in position in a storm High tension + low radial load capacity = long tensioner / many pads Internal friction may be lower than friction against pads.

12. Chute Cable installation Smooth and even load distribution Vessel heading restriction At maximum design tension Chute structural capacity Product integrity (bending + axial load) Over bending at tip of chute Top angle from analyses

13. Installation vessel with lay tower Seven Seas Scandi Neptune Pertinacia

14. Pipe lay vessel with reel and lay ramp

15. Pipe lay vessel with stinger

16. Stinger Stable support for pipes Checking with analysis Rollers to reduce friction Point loads Stinger radius below elastic bending radius Departure angle high enough to ensure smooth exit Avoid lift-up of pipe in whole stinger May impact vessel motion characteristics NOTE: picture shows stinger in elevated, not operational mode

17. Pipe lay vessel with J-lay tower

18. Typical laying situation Picture displaying vessel, water depth, product, and key geometric parameters

19. A salesman's death Oppgaven var: en selger vil skaffe firmaet ditt en jobb der en kabel med gitt en gitt kabel skal installeres av et fartøy som tåler et gitt toppstrekk. Bør du gripe inn? D=1000m W=10 kg/m R=5m H=500N Bunnstrekk: =0.29 deg! Toppvinkel: T=100500N Toppstrekk: Avstand til touchdown: X=29.98m hvor H = Horisontalt strekk i produktet i touchdown [N] w = Neddykket produktvekt [N/m] R = Minste bøyeradius over touchdown (i ”sag bend”) [m] a = Produktvinkel med vertikalen [radianer] D = Vanndyp [m] T = Produktstrekk i øverste ende [N] X = Avstand mellom toppunktet og touchdown

20. Installation analyses Establish weather criteria and a plan for laying. (Laying tables) Ensure robust and safe operations for personnel, equipment and flexible product. Low tension: over bending, axial compression, loop formation High tension: rupture, tensioner capacity, free spans Determine and verify survival conditions

21. Survival condition Cutting of product. More critical for power cables and umbilicals Installation of buoyancy elements Establish flexible ”S”- shaped configuration Step by step analysis to ensure product capacity while over boarding buoyancy Analysis gives guidance in when to pay in / pay out after installation Analyses: can the vessel maintain heading and position?

22. Steep slopes Uncontrolled sliding of the product Axial compression Free span formation Anchor at top of slope? Another anchor further down?

23. Other special considerations Deep water High top tension, tensioner and chute capacity Combined tension and bending at vessel interface Curve lay Sliding of product Low laying tension Laying around preinstalled piles etc

24. Power cable/umbilical from shore to offshore First end to shore: Shallow conditions: Attach buoyancy elements Floating Onshore winch pulls in through ditches or tunnels Friction, uncertain factor Actual bottom topography, strong currents etc may lead to changes in vessel position. Robustness needed Last end to shore: More complicated floating

25. Power cable/umbilical from shore to offshore Platform end: Installation through platform J- tubes Platform winch and forerunner through J- tubes Coupling of power cable / forerunner at vessel deck. Pull-in through J- tubes by platform winch. Challenges: Plans for vessel positions changed due to wind, platform managers and other unsteady phenomenon. Floating platform offset Clash with mooring lines, other risers etc Over bending at start of J tube

26. Power cable/umbilical from shore to offshore Installation of buoyancy elements: A “S”- shaped cable configurations at platform may be required. Buoyancy elements in final stages Use of clump weights or sea bed abnchoring may also be required

27. Power cable/umbilical from shore to offshore Challenges Compression / overbending near termination of buoyancy elements, touch down etc Clump weight tangles up Analyses to determine vessel movements and clump weight

28. Power cable/umbilical from shore to offshore Subsea termination Heavy end termination for subsea plug-in Bending restrictor or similar at neck Focus on bending moments at neck Lowered by the cable: head fall over Lowered by crane more controlled, but requires separation Analysis Reveal need for crane Determine required separation between crane tip and termination during lowering Calculate design loads for product loading