Suction Pile Jackets ExperienceWinddays Rotterdam WTC 13-14 June 2018Mark Riemers
EOWDC- Newcastle Yard
• SPT Offshore Introduction
•Ørested Borkum Riffgrund 1 WTG demo
• Statoil Dudgeon trafo jacket
•Vattenfall Aberdeen (EOWDC) 11# WTG SPJs
•Conclusions
Overview
Borkum Riffgrund 1 - SBJ
Dudgeon OWF Substation
Capabilities• EPC Contractor• T&I Contractor
Technologies• Self-Installing Platforms• Self-Installing Monopiles• Suction Pile Jackets .
SPT Offshore – Specialised Contractor
Founded in 1997> 500 suction piles
installed in O&G and renewables sectors
Independent, specialized contractor in suction pile foundations and anchors
Track record• Borkum Riffgrund 1 SBJ• Dudgeon OWF substation platform• Doggerbank 2x Metmast Removals• Ophir Wellhead Platform T&I• EOWDC (Aberdeen) Trial Installations• EOWDC Detailed Design Piles• EOWDC 11x SIWT Installations
EOWDC – Aberdeen, UK
•2-4 km offshore
•Water depth 19-32 m
•11 Suction Pile Jacket foundations
•92.4 MW peak capacity
•309 GWh annual power production
• Industry first:• MHI Vestas V164-8.4 turbines• Full wind farm on suction pile foundations
EOWDC – Foundation Design Contractors
Concept DesignH1 2016
Detailed DesignH2 2016 – H1 2017
Suction InstallationH1 2018
Jacket
Suction Piles
Developer
BoP Contractor Turbine Supplier
EOWDC – Fabrication
• Suction Pile Jackets fabricated throughout Europe and assembled with Suction Piles at Smulders yard in Newcastle
EOWDC – Site Conditions
•Water depth 19-32m
• Soil consists of 2-8m loose to medium dense sand over competent glacial clay soils
• Shallow bedrock at 20-25mbelow seabed
•This makes site unsuitedfor driven (mono)piles
EOWDC – Site Conditions
Suction piles selected because of:
•Very fast offshore installation• Sediment above bedrock well
suited for foundation•Virtually noisefree (100 dBa)•Minimal impact on marine
life•No need leveling systems•Easy removal -> reverse
installationEOWDC – Small Scale Pile Trials
EOWDC – Foundation Stiffness Matrix
Iteration process with Jacket Designer• Foundation stiffness matrix instead of
p-y curves as used for piles
𝑭𝑭𝑲𝑲 = 𝑲𝑲𝟏𝟏𝟏𝟏 ⋯
⋯ 𝑲𝑲𝟔𝟔𝟔𝟔
Alternative SPT Scour Protection System
• Frond mats pre-installed onshore onto the suction piles• Umbrella-like system, self-deploying during installation of the suction piles• Diverless deployment, immediate scour protection, marine life friendly• Cost reduction 50 ~ 60% compared to rock scour protection for a 3-legged
jacket
Alternative SPT Scour Protection System
TRL 1-2
• Concept Design
TRL 2-3
• Experimental Proof-of-Concept
TRL 4-5
• Validate in Hydraulic Lab
TRL 6-7
• Offshore Prototype
TRL 8-9
• Commercial Operation
• Self-deploying ‘umbrella’• Immediate scour protection• Marine life friendly
• Test of deployment system• In still water tank• Outriggers with mini frond mats
• Test of scour protection performance• Currents and waves in hydraulic lab• Frond mats around monopile and jacket
2018
• Full scale test in offshore conditions• At North Sea Offshore Wind Farm• Award of innovation funding pending
• Reduced LCOE for offshore wind• No extra offshore time or equipment• No rock dump, lower carbon footprint
To be announced
EOWDC – Installation Experience
•From trial installations to jacket installation
• Standard SPT rental pile testing early in design process• High L/D of 2.5 aim for refusal to test mitigating measures• Results used for further design optimizations
• Full sized suction Pile (L/D = 0.8)• Verify installation procedures• Verify installation performance• Verify mitigating measures
• Well-controlled, fast & predictable installation
Full-Scale Pile Tests
Small-Scale Pile Tests
Suction Pile Jacket
Installation
EOWDC – Small & Full Scale Suction Pile Tests
Small scale• 3 locations • 9 tests
• Normal installation• Pressure cycling
EOWDC – Small Scale Pile Trials
Full scale• 8 tests
A. Normal installationB. 1-way cyclingC. 2-way cyclingD. Cycling + water injection
EOWDC – 11 Suction Pile Jackets Successfully Installed
• Suction time 1 - 3 hours•Time HLVs on site 8 - 25 hours (average 12 hours)•All penetrations well within spec achieved 5cm vs allowed 30cm•All SPJ within 0.01 deg vs allowed 0.25 deg
EOWDC – Transport from Newcastle to site © Jim Scott, https://geordiecam.wordpress.com
Suction Pile Jackets – Conclusions
• It works!
•Fastest offshore installation ever
•Noisefree -> no impact on marine life
•Test Installations not required, but:• Optimize suction piles -> save steel• De-risk
EOWDC – Transport from Newcastle to site © Jim Scott, https://geordiecam.wordpress.com