Floatover Installation Method

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Emery O’Brien’
5 years ago
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1 Floatover Installation Method

2 Basic Floatover Manoeuvre

3 Barge Positioning In-between Jacket Top Structure Float through Section (front view) Floatover Support Frame Floatover Section Topsides Control Tug Barge Control Tug Jacket

4 Barge Docking Over Cone Receivers Head-on View Elastomer cell Stabbing cone Cone receiver Air gap at start (typ. 1.5m) Sand jack

5 Load Transfer Barge Ballasting Down Elastomer de fle ction during load transfer (typ. 350 mm)

6 Barge Undocking

7 Completed Floatover

8 Basic Floatover Manoeuvre Displaying Floatover Barge Anchoring Lines with Tugs Arrangements

9 Anchor Floatover Barge Floatover Barge Anchoring Holding Position Deck Anchor Pre-installed Jacket

10 Stern tug provides continuous pull aft Stern m oorings adjusted to maintain barge alignm ent with jacket Floatover Barge Bow Entry Bow m oorings adjusted to guide barge bow into jacket Bow enters jacket Bow tug passes through jacket then pulls barge in against stern tug

11 Stern tug continues to pull aft Stern m oorings adjusted to maintain barge alignm ent with jacket Release Bow Lines Release bow mooring Release bow mooring Bow tug continues to pull barge into jacket against pull of stern tug

12 Stern moorings partly slackened Topsides Mating Operation Slack tow line Barge ballasted down to transfer AMP1 deck weight onto the jacket legs Slack tow line Barge accurately held in position by stiff fenders on jacket legs and barge

13 Stern tug commences undocking Undocking Manoeuvre Stern moorings adjusted to maintain barge alignment with jacket Bow tug provides control pull forward

14 Stern tug continues to undock barge Release Stern Lines Stern moorings automatically go slack Release bow tow line

15 Barge is Free and is Towed Away, Topsides and Jacket Mating is Complete Release stern mooring Release stern mooring

16 Mating System Description

17 Mating System Summary See following slides for details of Leg Load Transfer System Automatic barge locating fender system Rapid barge entry and exit First-time stab in of leg docking cones Elastomeric shock absorbers in deck legs No dynamic leg to leg contact Barge rapid ballast system Barge ballast system + large external system Fully reversible at any time during load transfer Deck never relies on hydraulics for support during load transfer The deck is always supported directly by passive structural elements No risk of uneven support loadings Barge separation assisted by simple pullout block system

18 Barge Fender Systems PLAN OF BARGE Entry Guidance Fenders Bow Barge Entry Direction Stern Jacket leg Tim ber fender blocks bolted to steel base Barge HARDWOOD SWAY FENDER FOR DOCKING Jacket leg SWAY FENDER Steel reinforced hardwood panel down side of barge Steel support frame weldedto barge deck SURGE AND SWAY FENDERS

19 Fender System PLAN OF BARGE Entry guidance fenders Bow Skid rails Barge Entry Direction Stern Jacket leg Tim ber fender blocks bolted to steel base Hydraulic ram passes through skid rail Barge Fender bearing plate Steel reinforced hardwood panel down side of barge Steel support frame weldedto barge deck HARDWOOD SWAY FENDER FOR DOCKING Bearing plate Jacket leg MOVEABLE SURGE FENDER FIXED SURGE FENDER

20 LEG LOAD TRANSFER SYSTEM Topsidesleg (moving due to barge motion) Diaphragm attached to leg Topsidesleg (stationary after barge removed) Sliding piston containing shock absorbing elastomer Docking cone 2.5m gap between legsat floatover Elastomer Leg motion Compressed elastomer Time Gap between legs after barge removed: NO LEG CONTACTS DURING DYNAMIC PHASE 100 mm Leg descends on cone receiver controlled by sand jack Gap reduced to zero ready for weldout Motion attenuated by docking cone contacts as leg gap closes Docking cone receiver Docking unit welded to pile after cut-off Docking cone receiver lowered by sand jack Sand Sand jack Top of Jacket leg Reinforced diaphragm supports deck leg load Valve 1. BALLASTING DOWN (barge docked in Jacket) 2. AFTER LOAD TRANSFER (barge away from Jacket) 3. LOWER ON SAND JACKS (barge away from Jacket)

21 Support Block Arrangement Skid rail Pull-out Spacer block Removable Support Block Skid rail

22 Support Block Removal Topsides Topsides Seafastening Seafastening Support block Skid rail Barge Spacer block keeper plates removed 1. Seafastened after loadout 2. Cut Seafastenings during Load Transfer Topsides Actuator for support block removal Spacer block Topsides Support block pulled over by actuator Barge Barge 3. Remove Spacer Blocks as separation starts 4. Remove Support Blocks to release barge

mated with jacket Topsides Control tug tows barge clear

23 Undocking Topsides/barge ballasted down and barge ready to depart Control tug takes away barge leaving topsides mated with jacket Topsides Control tug tows barge clear of jacket Supporting frame Skid rail Barge ballasted down

24 Allowable Sea States For Floatover m 1.5m True North Platform North (True 35 o ) Stern 1.0m m Allawable Seastate Hs 2.0m 1.5m 1.0m 0.5m 90 0 Allawable Seastate Hs 0.5m 1.0m 1.5m 2.0m m Boundary of maximum allowable seastate for floatover Bow 1.0m 60 0 Example shows allowable seastate Hs = 2.0 m for waves approaching at 18 deg from bow m 2.0m Allawable Seastate Hs Angle of wave approach relative to barge bow

25 Floatover Operation Schedule 0 HOURS Bow tug enters jacket Barge enters jacket 60 min Ballasting: Close air gap 35 min Ballasting: Weight Transfer 40 min Ballasting: Separate barge 10 Undock barge 20 min Barge free hours 45 minutes Ballast times are based on: 40,000 te/hour Installed pump capacity 30,000 te/hour Firm capacity (allowing for breakdowns and losses) 15% additional time for normal operational delays

26 Floatover Installation Method Thank You

27 Contacts

Floatover Installation Method

Floatover Installation Method Basic Floatover Manoeuvre Barge Positioning In-between Jacket Top Structure Float through Section (front view) Floatover Support Frame Floatover Section Topsides Control Tug