ECOSSE Subsea Systems
“because we think differently....”
Ecosse Subsea Systems Established in 1996, Ecosse Subsea Systems has earned a global reputation for outstanding service delivery to the subsea oil and gas and offshore renewable energy markets.
•Trenching •Subsea and Deepwater Lifting •Technology Development •Personnel
–Offshore Operations –Engineering –Consulting –Mechanical and Electrical Technicians
“because we think differently....”
Our Services
“because we think differently....”
Existing Clients
During 2008-2010 Ecosse Subsea has performed contracts for various customers including:
• Subsea 7
• Clough
• CNR International
• CRC Evans
• DOF Subsea
• Fairfield
• Geolab
– Bibby Offshore
“because we think differently....”
• Houlder Offshore
• ISS
• Ithaca
• PetroCanada
• PSN
• Saipem
• Shell
• Technip
Mike Wilson Managing Director (background)
• Engineering Diploma RGU (RGIT) Aberdeen
• Offshore technician on trenching system since 1985
• Offshore Manager on towed ploughs, pipelay, subsea lifting since 1990
• Project engineering on trenching, pipelay projects
• Project Manager on trenching projects since 1995
• Client representative on trenching, pipelay, heavy lifting projects since 2000
• Founder Ecosse Subsea in 1996
‘because we think differently...’
Arctic and deep trenching, backround
• Ice runs aground in shallow water in the Arctic seas, and cuts into the seabed as it is pushed further by wind, current, and the pressure of other ice. Dramatic patterns of seabed gouges are revealed by side-scan sonar. Often the gouges are several metres deep. Repetitive gouge mapping confirms that gouging is a contemporary process, rather than a relic from earlier periods in which the water level and the ice climate were different (Chua, Palmer, Tjiawi)
• Soft clays
• Stiff and hard clays
• Glacial till
• Bedrock
• Steep slopes and complicated morphology
‘because we think differently....’
glacial Till/bedrock/glacier
Typical Arctic trench specification
• Trenching to depths greater than current industry norms - burial depths greater than 3m, with potential trench depths as much as 7m
• Trenching in soil conditions that are difficult and highly variable
• Trenching in water depths beyond the majority of trenching requirements - water depths up to approximately 300m
• Operating in harsh marine conditions
‘because we think differently...’
Pre-cutting or post lay trench?
• Trenching project is likely to last several months in very challenging conditions.
• Which method would you choose? A system that holds on to your pipe/cable on every pass or not?
• Backfill? A requirement?
we think differently
What do yesterday’s trenching tools look like?
‘because we think differently...’
What do yesterday’s trenching tools look like?
we think differently
‘because we think differently...’
Subsea Trenching System pedigree
• Concept - Ecosse Subsea Systems
• FEED –Engineering Business (EB)
• Detailed design and FEA- Wilton Group
• Fabrication of major assemblies – Dales Peterhead
• Assembly - Maritime Developments Peterhead
• Pre-project trials TBA
SCAR Plough
“because we think differently...”
• A modified conventional plough designed to cut a single pass Trench of 1.4m
• 5m+ Trenches in multi pass mode and in difficult terrain
• Can be launched and recovered like an anchor, primarily from a conventional vessel of around 150T bollard pull, but depending on location and soil type can be operated from any suitable vessel, e.g. a DSV
SCAR TOOL
Plan
SCAR with
multipass skid
skid
6m wide share
“because we think differently...”
Single Pass 1400mm depth
Multi Pass 1.2m-2m
SCAR Support
Vessel
SCAR
SVS
control
skid
SCAR SUPPORT VESSEL
SCAR Tool
“we think differently”
SCAR Towing Operations
SCAR
Support
Vessel
Seabed SCAR
• SCAR has almost no moving parts and will be the most reliable plough
• Plough can be built in different sizes to suit products and bollard pulls
• Plough position can be monitored real time
“we think differently”
SCAR 1st Cut
Flat skid
1st Cut
Trench
SCAR 2nd and
subsequent cuts
with multipass skid
2nd Cut Trench
seabed
1st and 2nd cuts with SCAR
seabed
“we think differently”
Verification of Model
To verify the behaviour of the plough model during impact with a boulder, exaggerated deformation images were used
“we think differently”
Stress contour image of Plough (Rear view)
FEA Results
“we think differently”
SCAR fitted with post lay burial roller cradles
1stpass post lay burial 2nd pass asymmetric trenching
1st Pass 2nd Pass
“we think differently”
SCAR plough cable trenching post lay asymmetric multi-pass trenching
TRENCH TOP LEVEL
Simultaneous MFEIf the trenching requirement exceeds a depth of 2.5m, MFE equipment has to be fitted to remove the spoil. At these trench depths the mouldboards are no longer effective in clearing the spoil and it would simply flow around and over, refilling the trench. The MFE equipment jets the spoil and small boulders up and out of the trench preventing trench infill.
An MFE can also be deployed from a surface vessel, behind the plough along the trench, jetting away the remaining spoil with an ROV monitoring position
Does size matter?
• Does your trenching system require massive bollard pull or high electrical power from your engines?
• 250-500Te lifting devices to launch and recover in 2m seas?
• Ships accommodation of 80+ persons
• Have you considered other lifting and deployment methods?
we think differently
Until now the size of the plough is totally dependant on the support vessel –namely the handling capacity of the stern roller or the crane/A-frame. Bigger ploughs are possible using ESS subsea gel lifting techniques for deployment
“we think differently”
Thank you
www.ecosse-subsea.com