SUBSEA INSTALLATION WITHOUT A HEAVY LIFT VESSEL A STEP CHANGE IN SUBSEA INSTALLATION
PRODUCT An alternative to an HLV for the recovery of subsea structures Low cost Allows even the smallest crane vessel to recover large structures Operations largely independent of weather Safer than a conventional lift Schedule flexibility 2
MARKET Installation or decommissioning of subsea structures 100t to several 1000t Optimum range 200t to 1000t 80m to 3000m water depth Hostile environments 3
ECONOMICS SDS + AHT @ $50k/day compared to an HLV @$1m/day Minimal risk of weather delays Year round operation + VS 4
SAFETY AND ENVIRONMENT Low tech / fail safe Operations can be suspended at any time (no point of no return) Operations insensitive to weather Negligible dynamic loading Structures are not recovered to deck Reduced risk of catastrophic loss Fewer personnel Low carbon footprint 5
THE SDV MAIN COMPONENTS TOW CHAIN CLUMP WEIGHT CONTROL WEIGHT CONTROL CHAIN CHAIN BUOYANCY BUOYANCY MODULES MODULES CASTLE E CONTROL CONTROL TOWER TOWER BALLAST BALLAST LOCKER LOCKER STRUCTUR STRUCTURE E FLOODABLE FLOODABLE HULL HULL 6
SYSTEM VARIATIONS 7
Lifted LOAD OUT Float off Submersible barge Floating dock Dry dock SUBMERSIBLE BARGE 8
Shallow surface tow SURFACE TOW Flood tanks Insert tow chain clump weight Pay out tow wire 9
Adjust tow wire and speed Slow down to lower the system Pay out tow wire to lower clump weight SUBMERGED TOW 10
LOWER STRUCTURE AHT disconnects the tow wire Lower control chains into the control chain towers Slew crane to create lead on control chains Pay out chain until the system is neutral 11
Lateral control CONTROL CHAIN TOWERS Rotational control Vertical control On bottom weight 12
DYNAMICS Response governed by the natural period of the system Typically the natural period of a >1000t system > 120s Increased weather window for set down Minimal dynamic loading on the surface crane and structure 13
INSTALLATION AHT manoeuvres the system to final target 14
BALLASTING Lower system slowly on to target Pay out remaining control chain into control chain towers Install ballast weight to balance the payload weight 15
LIFT OFF WROV disconnects payload Deploy down lines and reconnect to the control chains Recover the control chains until the subsea deployment vessel starts rising Continue raising until well clear of subsea assets 16
RETURN TO SHORE Recover control chains until clear of the control chain towers AHT tows the subsea deployment vessel back to shore 17
DYNAMICS FULL (30x) VESSEL & SDV (SHADOWS) SDV CLOSE-UP (SHADOWS) 18
SEASTATE STATISTICS Subject to operational windows and seasonal variations 19
INHERENT SAFETY Total Loss Minimised Close To Neutral Insensitive to weather No point of no return Rigging failure Buoyancy loss TOW WIRE FAILURE (10x) 20
21
INSTALLATION POTENTIAL APPLICATIONS DECOMMISSIONING 100t to several 1000t structures Water depth 80m 3000m Hostile environments Operation is fully reversible for new structures Interfacing flexibility with existing structures Minimal dynamic loading Existing structures recovered without lifting to deck Large skip 22
Low CAPEX/OPEX ADVANTAGES Simple and robust technology Safe Suitable for deep water and harsh environments Heavy lift capacity Greater availability compared to HLV Potential for phased installation and early production Potential for fewer structures, tie ins and interfaces 23
HLV SUPPLY LIGHTER (<150t) Market is mainly over supplied Generally not suitable for deepwater / hostile locations MIDMARKET (150T 400T) Most of the vessels have other primary functions Capacity drops significantly in deep water / hostile locations LARGER (400T+) Very limited availability Opportunities exist for alternative lifting solutions 24
STATUS UK patent was awarded September 2010. Outline designs and installation procedures have been developed for the Gorgon and Shtokman developments. Detailed study performed for Apache for the installation of two structures at Forties. Technical evaluation has been performed by a major installation contractor resulting in an offer to buy the patent outright. SDS is seeking a partner to assist in bringing the system to market. 25