sscs track record
TRANSCRIPT
www.sscsystems.com [email protected]
+44 1493 443380
Seabed Scour Control Systems Ltd
SSCS Frond Mats Track Record
March 2015
www.sscsystems.com [email protected]
+44 1493 443380
Total Myanmar Pipeline Freespan Rectification Installed by Bibby Offshore
March 2015
A quantity of SSCS Weighted Frond Mats were supplied to Bibby Offshore Singapore on behalf of Total Myanmar for installation along one of their pipelines on the Yadana field in the Andaman Sea to provide freespan rectification and future protection from scour in water depths of approximately 50m.
Bibby Offshore executed the deployment of the Mats from the DP2 ROV support vessel, Bibby Spring, utilising the SSCS installation frame and the Quasar Work Class ROV. The ROV was able to manipulate the Frame subsea without any issue, and deployment of the Mats was executed within the allocated time frame; a total of 2 days was allocated for Frond Mat installation, and the full quantity were deployed in under 24 hours.
Initial feedback from Bibby following Mat deployment indicates that:
“Total are happy with the installation”.
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GMS Endeavour, Anglia A – North Sea June 2014
A quantity of SSCS Weighted Frond Mats were delivered to the GMS Endeavour during June 2014 at the Great Yarmouth Outer Harbour prior to deployment at the Anglia A site in the North Sea to protect the platform legs from scour where the water depth was approximately 20-25m with a sandy seabed.
The SSCS Operations Manager provided product and installation training on deck whilst moored up at the outer harbour to prepare the GMS crew for installation which was carried out using a crane with no additional subsea intervention eliminating the additional cost of divers or an ROV resulting in a cost saving of over 70%.
An additional number of SSCS Weighted Frond Mats were purchased following this successful deployment for the GMS Endurance at another location.
We also received the following feedback addressed to our Sales Manager, Adam Tucker, from GMS’s Operations Manager, Ken Roby, who communicated daily during both operations:
“I personally think that the service that SSCS have given and yourself personally has been very good, and very professional, and I would have no hesitation in using your company again or recommend SSCS to others who maybe after these services.”
www.sscsystems.com [email protected]
+44 1493 443380
Pertamina, Indonesia Scour Rectification for Offshore Platforms
2013 – 2015
SSCS supplied 255 Type 12 Frond Mats to Pertamina at the end of 2012 for works commencing during 2013, 2014 and 2015 for scour rectification around a number of offshore platforms.
The Frond Mats are being used around exposed piles classed as “high priority” in order to remediate scour and provide permanent protection from the future development of scour. These platforms included the AVSA Flare, BD, BM and BZNA Wells, along with numerous others.
The platforms are located between 5km and 100km from the Javanese coastline between Cirebon in the east and the Pulau Seribu archipelago in the west – a distance of approximately 200km.
Installation was carried out at the sites throughout 2013 and 2014, and Mats continue to be installed today.
Feedback to date indicates the successful implementation of the Mats and the continued use of our solution demonstrates the effectiveness of the Mats at arresting sediment and providing the required level of protection from scour around high profile assets.
“...they are working well at one platform which was re-visited some time after the installation”
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Repsol, Atwood Beacon – Jaguar 1, Guyana February 2012
A large quantity of SSCS Type 12 Frond Mats were delivered to Repsol Guyana during January / February 2012 to provide the required scour protection for the spud cans of the Atwood Beacon jack-up rig on the Jaguar 1 well.
The Mats were installed according to the detailed layout design provided by SSCS during the technical proposal stage and the post installation survey videos conducted using an ROV indicated successful placement around the cans.
Communication with Repsol following Mat installation as recently as February 2015 has provided feedback that the Mats are working successfully at providing the required protection from scour around the spud cans, and that future Mat use has been scheduled when the rig moves location in 2016.
Video footage of the SSCS Frond Mats post installation can be found on our YouTube Channel – www.youtube.com/c/SSCSLtd
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SASMAP Project, EU 2012-2015
SASMAP’s purpose is to develop new technologies and best practices in order to locate, assess and manage Europe’s underwater cultural heritage. SASMAP will take holistic- and process-based approaches to investigate underwater environments and the archaeological sites contained therein. This is necessary regardless of whether or not investigations are research driven or in connection with subsea development. Investigations of underwater heritage which are associated with subsea developments in Europe often require pre-disturbance studies to comply with the Treaty of Valletta (1992).
Within SASMAP a holistic approach will be taken to locating, assessing, monitoring and safeguarding underwater cultural heritage. This will involve developing and utilising tools and technologies to allow “down-scaling” from the large scale regional level, moving on to the local site level and finally to the individual components of a site.
SSCS’s involvement was to provide a sustainable solution to the threat of damage to the heritage sites by underwater currents that cause sediment to be removed from the sites exposing them and causing the seabed to become unstable.
The result was current speed reductions of up to 93.3% using standard density and height SSCS Fronds.
More information on the SASMAP Project can be found at www.sasmap.eu
www.sscsystems.com [email protected]
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Arklow Bank Offshore Wind Farm, GE Energy Foundations T4 and T5
2011
Specially designed SSCS Frond Mats were installed around two of the 6.3 metre diameter Turbine Pile Foundations and along associated power cables to rectify scour and provide permanent protection following the failure of rock armour.
Rock armour, installed shortly after pile installation to provide scour protection, was found during post installation surveys nine months after installation to have dissipated and to have sunk below the natural seabed level exposing the pile and cables and creating scour to a depth of 4 metres and extending to approximately 20 metres from the pile edge.
The SSCS Frond Mats were installed between and around the few remaining rocks to rectify this scour, reinstate the seabed soils and provide long term protection.
The 2011 Completion Report of the remedial works provided by GE Energy, and prepared by Island Maritime Ltd indicated ongoing successful performance of the SSCS Frond Mats:
“Initial observations of the effect of ... Frond Mattress installation are positive.”
“Immediate observations of the effects of Frond Mattresses around WTG 4 & WTG 5 are very positive”
www.sscsystems.com [email protected]
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SINOPEC China, Bohai Bay 2006-2015 (ongoing)
Seabed Scour Control Systems Ltd have been supplying Type 12 and Type 25 Frond Mats to major Chinese Oil & Gas operators since 2006, which continue to be installed to rectify scour and provide permanent scour protection for assets such as subsea pipelines and offshore platforms.
SSCS Frond Mats were originally supplied to the Sinopec owned and operated Shengli Field in Bohai Bay, China approximately 5 miles off the East Coast of Shandong Province for a number of Scoured and Exposed Pipelines.
This ongoing scour protection project started in 2006 and over 1000 SSCS Frond Mats have since been installed to protect numerous Pipelines and Platform Riser Spools.
The Frond Mats that have been installed have proven to provide the required protection for the pipelines and riser pipeline spools at the Shengli Field and as a result SSCS continues to supply Mats each year for continuing works at the Shengli Field and to meet additional protection requirements that arise.
www.sscsystems.com [email protected]
+44 1493 443380
Shell Brunei, Pipeline Freespan Rectification and Stabilisation
2006 – 2015 (ongoing)
SSCS Frond Mats were first installed in 2006 along each side of a free-spanning 20” diameter pipeline to rectify the existing scour beneath the pipeline and to mitigate further scour propagation.
The free-span was approximately 70 metres long and 0.2 metres deep with intermittent touchdown points.
The post Mat installation ROV General Inspection Survey carried out in 2007 showed that the free-span had been corrected and that the pipeline was again in contact with the re-established seabed and that there was no scour propagation beyond the Mats.
Extracts from the follow up survey dated 03/09/2007
“The 6 o/c position of the pipeline was in contact with the seabed at the edge of the mat, and there were no signs of further scouring observed under the pipeline, going past the mat...”
“The ROV then relocated to the west side of the pipeline opposite the second mat, and it was observed that the pipeline was in contact with the seabed at the 6 o/c position, with no freespan seen beyond the mat going towards the CPRJ-01. The Scour Correction mat appeared to have arrested the scouring on the CRPJ-01 side of the freespan...”
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Bam Nuttall Norfolk Broads River bed and Bank Rectification
2006-2008
The UK East Anglia Broadlands river banks and beds have, and continue to be, eroded by fast flowing tidal currents and the wash created by motorised leisure craft.
The Broadlands Flood Alleviation Project Team who also have responsibility for rectifying erosion and re-establishing the eroded areas elected to install SSCS Frond Mats at a severely eroded location on the River Waveney where tidal currents have been measured at up to 3knots.
Specially designed Frond Mats were installed in 2006 across the widest point of an eroded stretch of the river to capture transported sediment and reinstate the river bed and bank inside the matted area.
Post installation observations have shown that sediment has been quickly deposited behind the matted area and continues to develop.
Further installation of the SSCS Frond Mats has since been carried out to facilitate the same solution on other Broadlands Rivers.
www.sscsystems.com [email protected]
+44 1493 443380
Bass River, USA – National Grid Reinstatement and Protection of polluted riverbed
2005
125 SSCS Type 12 Frond Mats were installed to re-establish and re-instate the Bass River bed where it had been excavated following the dredging of coal tar contaminated sediments from within the river.
The installation of a sediment cap to cover residual contamination beneath then took place and SSCS’s scope included installation of approximately 16,500 square feet of SSCS Frond Mats to mitigate potential loss of the sediment cap due to propeller wash.
In the October 2006 and November 2007 post installation surveys it was found that:
“...the Mats were collecting sediment while maintaining the subaqueous cap and were providing a habitat for various forms of marine life and vegetation.”
Following the completion of further post installation surveys carried out in 2008 and December 2009 the SSCS Frond Mats were proven to be fully established and effectively preventing scour of the capping material.
“The underwater investigation indicated that the majority of the scour control mats are generally in good condition...there continues to be evidence of the mats being silted-in and providing a habitat for various forms of marine life and vegetation. No sheens or other evidence of coal tar was observed.”
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Arklow Bank Offshore Wind Farm, GE Energy 1m Diameter Met Mast
2004
Arklow Bank is a shallow water sandbank located 10 km off the east coast of Ireland in approx: 3mwd. It is exposed to strong currents, frequently exceeding 2m/s, breaking waves and has a dynamic sand/gravel seabed.
Type25 SSCS Frond Mats were installed around the 1.0 metre diameter Met Mast Pile Foundation standing in 5mwd to prevent scour and provide permanent scour protection.
The post installation survey showed the successful application and effectiveness of the Mats with a build-up of sediment providing a stable protective sand bank such that the buoyant fronds 1.25metres in length were completely buried and no longer visible.
www.sscsystems.com [email protected]
+44 1493 443380
Marathon Oil, Concrete Gravity Based MOPU, Gabon May 2004
The Marathon MOPU Concrete Gravity Based Structure was experiencing serious scour around its entire periphery.
Sand Bags had previously been installed to prevent scour but these had failed to provide the required protection due to being a ‘hard’ solution, thus being susceptible to secondary scour and dissipation.
SSCS Frond Mats were installed in 2004/2005 to rectify existing scour and provide permanent protection by slowing the tidal currents and removing the energy necessary to erode the seabed, i.e. scour, around the platform.
There has been no further scour and the gravity base is now permanently protected.
www.sscsystems.com [email protected]
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OMV, Australia – Patricia-Baleen Pipeline, Patricia Jan-Feb 2003
In 2003 a quantity of SSCS Type 12 and Type 25 Frond Mats were purchased by OMV to provide protection for the 12” Patricia-Baleen subsea pipeline and an umbilical offshore Victoria, SE Australia.
During December 2002 SSCS were contacted by Intec Engineering of Perth, who were acting as OMV’s consultants, requesting recommendations for covering and protecting the pipeline installed during 2001.
The requirement arose as a result of environmental objections raised by local fishermen to the pipeline which passes through near-shore fishing grounds, and which was partially exposed over a 180m length at a near-shore location as were some of the associated concrete stabilisation blocks.
SSCS recommended the installation of its Frond Mats to cover and protect the pipeline and stabilisation blocks at both locations; OMV accepted the recommendations and approved installation of the SSCS Frond Mats to protect the pipeline and an exposed umbilical.
Availability and early delivery was essential for this work and SSCS delivered Frond Mats, together with finalised Mat installation procedures and layout drawings by air freight within 7 days at the end of January 2003.
www.sscsystems.com [email protected]
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Nuclear Electric – Outfall and Intake tunnel, Sizewell `B' Power Station
June 1991
Scour Control Mats were initially installed during June 1991, with a small quantity later in the year to protect the Inner End, Mid Point and Outer end of a Concrete Box Structure installed out from the beach .
The seabed consisted of 0m to 7m deep fine to medium sand of medium density with isolated layers of silty clay and occasional shell fragments.
1.35m/sec seabed currents are experienced at the sight on a annual basis, with known speeds to exceed 2m/s on occasion and a tidal range of up to 6.3m.
An inspection of the SSCS scour control mats laid at the out-fall and at the intake tunnel at Sizewell `B' Power Station from the beach out to sea was conducted by Ocean Technical Services on the 19th, 20th March, and 5th April, 1992 and concluded that:
“having plotted the results of each section survey, it would appear that .. the Scour Control Mats have been successful in preventing scour.”
“Divers also reported total sediment cover of the four mats laid at the intake location.“
“As detailed in the full intake survey data, considerable scour is evident where NO protection has been provided by mats.”
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Flume Trials River & Harbour Laboratory, at the Norwegian Institute
of Technology, Trondheim
In flume tank trials the efficacy of the SSCS frond system was proven at flow speeds up to 10 knots (5.1 m/s).
In constant flow trials the velocity at a height of 0.1m above the bed was reduced in the trial of 4 (four) rows of fronds to 26% of the constant free flow; and in a variable flow trial at the same 0.1m above the bed the flow was reduced to 8% of the free flow. A seabed or river bed is stabilised immediately on installation of an SSCS buoyant frond system.
The maximum peak tidal flow of any live SSCS frond installation at the time of these trials was one for Exxon (Mainline Pipelines) in the Afon Taf Estuary off the Severn which had a 7 knot flow (3.6 m/s) at flood run off combined with spring tide ebb flow, and at spring tides endured a major up-stream "bore" wave. Standard height fronds were used except over the pipeline where 0.350mm high fronds were used at the request of the NRA (and the local waterways body) and at this site the frond system was proven effective and the installation remains successful.
A somewhat similar installation for Transco (British Gas) for a 24" pipeline crossing the Menai Straits also used half height fronds throughout in a clay / fine sand seabed and this has proved successful and created a firm dense natural sediment bank of low profile over the pipeline. Again environmental approval was sought and given.
www.sscsystems.com [email protected]
+44 1493 443380
Frequently Asked Questions
Q: What is the field life of the SSCS Frond Mats?
A: The SSCS Frond Mats are constructed from materials that have a theoretical permanent life within marine environments as they are not susceptible to degradation. The first Mats were installed in 1984/85 in the Southern North Sea and remain in place today and have required zero maintenance or re-application during this period. The SSCS Frond Mats are considered the only permanent solution to scour.
Q: What engineering is required?
A: Due to the way in which the SSCS Frond Mats prevent scour by removing the energy required to cause it, engineering in the typical sense that is associated with other methods is not required as, for example, no various forms of Mat are required (e.g. Filter layers). Immediate stabilisation of the top layer(s) of sediment is achieved following deployment of SSCS Frond Mats. SSCS are able to provide Frond Mats of specific shapes, sizes and to suit various deployment methods depending on the project / client requirements, however the Frond density, length, etc is not altered.
Q: How are the SSCS Frond Mats installed?
A: SSCS Frond Mat installation is dictated by the project / client requirements. Due to being fully adaptable the Mats can be installed in many forms including but not limited to:
- Being installed using a deployment frame whereby the Mats are held into position on the sea/river-bed by weighted down edges (these Mats are held in stock)
- Being unrolled on the seabed by divers and held in position with a series of anchors (these Mats are held in stock)
- Being pre-attached to structures onshore prior to deployment such as concrete mattresses, concrete form works, cable crossings, etc with Frond activation occurring by releasing the ‘safe net’ during retrieval of the installation frame.
- Being pre-attached to structures onshore prior to deployment then unrolled on the seabed by ROV or divers.
Q: What is the impact on the environment when using SSCS Frond Mats?
A: The SSCS Frond Mats are often considered the most environmentally friendly solution to scour and have been found to be totally accepted by the natural environment. As the materials used do not leach or degrade, there is no negative impact; in fact, the Mats have been found to enhance the local natural environment whilst the Fronds are exposed. The SSCS Frond Mats have also been approved by various fishing organisations / authorities.