SUBSEA INSTALLATION WITHOUT A HEAVY LIFT … Presentation (V11).pdf · Subsea Deployment Systems Ltd. SUBSEA INSTALLATION WITHOUT A HEAVY LIFT VESSEL A STEP CHANGE IN SUBSEA INSTALLATION

Subsea Deployment Systems Ltd.

SUBSEA INSTALLATION WITHOUTA HEAVY LIFT VESSEL

A STEP CHANGE IN SUBSEA INSTALLATION


2

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


3

MARKET•Installation or decommissioning of subsea structures

•100t to several 1000t

•Optimum range 200t to 1000t

•80m to 3000m water depth

•Hostile environments


4

ECONOMICS•SDS + AHT @ $50k/day compared to an HLV @$1m/day

•Minimal risk of weather delays

•Year round operation

+ VS


5

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


6

THE SDV MAIN COMPONENTSCONTROL

CHAIN

CONTROL TOWER

TOW CHAIN CLUMP WEIGHT

CASTLE

STRUCTURE

BUOYANCY MODULES

FLOODABLE HULL

BALLAST LOCKER

CONTROL CHAIN

CONTROL TOWER

TOW CHAIN CLUMP WEIGHT

CASTLE

STRUCTURE

BUOYANCY MODULES

FLOODABLE HULL

BALLAST LOCKER


7

SYSTEM VARIATIONS


8

LOAD OUT•Lifted

•Float off

•Submersible barge

•Floating dock

•Dry dock

•SUBMERSIBLE BARGE


9

SURFACE TOW•Shallow surface tow

•Flood tanks

•Insert tow chain clump weight

•Pay out tow wire


10

SUBMERGED TOW•Adjust tow wire and speed

•Slow down to lower the system

•Pay out tow wire to lower clump weight


11

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


12

CONTROL CHAIN TOWERS•Rotational control

•On‐bottom weight

•Lateral control

•Vertical control


13

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


14

INSTALLATION•AHT manoeuvres the system to final target


15

BALLASTING• Lower system slowly on to target

• Pay out remaining control chain into control chain towers

• Install ballast weight to balance the payload weight


16

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


17

RETURN TO SHORE• Recover control chains until clear of the control chain towers

• AHT tows the subsea deployment vessel back to shore


18

DYNAMICS

SDV CLOSE-UP (SHADOWS)VESSEL & SDV (SHADOWS)

FULL (30x)


19

SEASTATE STATISTICS• Subject to operational windows and seasonal variations


20

INHERENT SAFETY

TOW WIRE FAILURE (10x)

• Total Loss Minimised – “Close To Neutral”

• Insensitive to weather

• No point of ‘no return’

• Rigging failure

• Buoyancy loss


21


22

POTENTIAL APPLICATIONSDECOMMISSIONING

• Operation is fully reversible for new structures

• Interfacing flexibility with existing structures

• Minimal dynamic loading

• Existing structures recovered without lifting to deck

• Large skip

INSTALLATION

• 100t to several 1000t structures

• Water depth 80m – 3000m

• Hostile environments


23

ADVANTAGES•Low CAPEX/OPEX

•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


24

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


25

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.


Documents

SUBSEA INSTALLATION WITHOUT A HEAVY LIFT … Presentation (V11).pdf · Subsea Deployment Systems Ltd. SUBSEA INSTALLATION WITHOUT A HEAVY LIFT VESSEL A STEP CHANGE IN SUBSEA INSTALLATION