ECOSSE Subsea Systems subsea - subsea europe paris … · • Technip . Mike Wilson Managing...

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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

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