Boskalis Westminster has worked on a wide variety of contracts and projects over many years. We have learned to manage complexity, mitigate risks and simplify execution. Whatever the requirements - whether it is standard maintenance dredging, a complex project requiring different engineering and design elements, or long term services - Boskalis Westminster can tailor innovative and competitive solutions.
Wintershall RAVN and A6-A
Wintershall Noordzee B.V. installed a new remote platform RAVN as a crude production tie-back to A6-A. RAVN is a remote and unmanned crude well unit. Utilising a dry-tree design, all control, power and metered injection for the well will be via the 18.2-km control umbilical between the new satellite platform RAVN in the Danish sector and the operational platform A6-A in the German sector. The umbilical forms the entire link between the remote platform, supplying and controlling all functions and ensuring continual feedback and monitoring of RAVN. The umbilical supplies all the necessary input data, control and feedback to eliminate the usual day-to-day requirements of direct human contact. The umbilical was installed from RAVN first end to second end pull-in at A6-A end. Platforms are located in the Danish territorial waters in the North Sea (RAVN) and German territorial waters in the North Sea (A6-A). The umbilical was connected/pulled into RAVN via a J-tube and internal conductor to the RAVN topside -TUTA. RAVN - first end with pull-in to topside deck via a J-tube - was laid in corridor separate from the 8-inch pipeline between RAVN and A6-A and second end pull-in using the quadrant method at the A6-A platform. SCOPE OF WORK Prepare project planning for Boskalis’ scope of work. Survey work, including post-burial survey. Perform route engineering and installation engineering to optimize the performance of the installation scope, including Orcaflex analysis for laying, pull-ins, loads and dynamics, as well as a detailed burial assessment study (BAS). Prepare platform on RAVN and A6-A. Define umbilical length together with the client. Umbilical load-out at Hartlepool (UK) onto the installation vessel Ndurance. Installation and hang-off of umbilical termination heads – topsides. Crossing 36- & 40-inch live gas pipelines. Pull-in at RAVN & A6-A platforms – direct from vessel as part of SIM-OPS. Umbilical lay and bury scope – minimize on seabed exposure. Mobilize and demobilize all installation spreads for Boskalis’ scope. Provide engineering support during the offshore umbilical installation, including simultaneous burial. Provide QHSE management for Boskalis’ scope. Process and deliver as-built data. Mobilize and demobilize all installation spreads for Boskalis’ scope.
Wintershall Noordzee B.V. installed a new remote platform at L6-B as a gas production tie-back to L8-P4. L6-B is a remote and unmanned gas well unit. Utilising a dry-tree design, all control, power and metered injection for the two wells will be via the 19.5-km control umbilical between the new satellite platform L6-B and the operational gas platform L8-P4. The umbilical forms the entire link between the remote platforms, supplying and controlling all functions and ensuring continual feedback and monitoring of L6-B. The umbilical supplies all the necessary input data, control and feedback to eliminate the usual day-to-day requirement of direct human contact. The umbilical was installed from L8-P4 first end to second end pull-in at L6-B remote end. Both platforms are located in Dutch territorial waters in the North Sea. The umbilical was connected/pulled in to L6-B via a J-tube and internal conductor to the L6-B topside - TUTA. The umbilical will be installed from L8-P4 - first end with pull-in to topside deck via a J-tube, laid in corridor separate from the 8-inch pipeline between L8-P4 and L6-B. FACTS AND FIGURES Water depth 30-35 meters Challenging North sea conditions. Challenging soft seabed. Fast-track project, with a short lead-time between award and installation – Feb 2014, July/Aug installed. Stepped phase process of pull-in, laying and burial ops. Completed on time, with no incidents. Umbilical loaded quickly and safely. Umbilical length 19.5 km. Burial scope of single pass burial of umbilical minimum requirement of 1m TOC (top of cover). SCOPE OF WORK Prepare project planning for Boskalis’ scope of work. Survey work, including a pre-burial, as-laid and post-burial survey. Perform route engineering and installation engineering to optimize the performance of the installation scope, including a detailed burial assessment study (BAS). Prepare platform on L8-P4 and L6-B. Define umbilical length together with the client. Umbilical load-out at DUCO Newcastle (UK) onto the installation vessel Ndurance. Hang-off of umbilical end. Crossing 36-inch live gas pipeline Callantsoog. Pull-in at L6-B & L8-P4 platforms – direct from vessel as part of SIM-OPS. Mobilize and demobilize all installation spreads for Boskalis’ scope. Provide engineering support during the offshore umbilical installation, including burial. Provide QHSE management for Boskalis’ scope.
Eastbourne Beach Recharge
Due to erosion by wind, waves and rising sea levels, the beach front at Eastbourne needed to be reinforced. The previous campaign to improve coastal defence was carried out in 1998 and in 2011 the shoreline no longer fulfilled the design criteria for safe coastal protection.Eastbourne Borough Council (EBC) developed a scheme comprising the recycling of existing material, particularly in environmentally sensitive areas (SSSI – Beachy Head) and the importing of bulk quantities for the rest of the beach frontage. The sequence of the works was to execute the recycling first and subsequently fill the groyne bays to the required profiles with imported shingle. The site stretched over a total length of 5.5 km, from Beachy Head in the west, along the whole of Eastbourne front, to Langney Point in the east. The design profile varied over the length of the site, with the aim of achieving a design crest width and height with seaward slopes of approximately 1 in 9. All dry earth moving was subcontracted to Ovenden who executed the works with up to 3 excavators, 4 bulldozers and 10 dump trucks working at the same time. The imported shingle was mainly dredged at Owers Bank /Area 435. The material supplied complied with the design requirements, having a D50 in the order of 16m. As this material had to be pumped ashore via an 1100m long sinker line, a heavy duty dredger with substantial installed power was needed. The Prins der Nederlanden was therefore mobilised, with a total of 19,000 kW installed capacity, every one of which was required during pump ashore.
Eastoke Nourishment Works
Hayling Island is fronted by a shingle beach, spanning its entire southern shoreline. Regular storm wave attack and the consequential threat of overtopping dictates the need for constant management in order to prevent flooding of properties in the lee of the beach. Eastoke, situated at the eastern end of the frontage, is particularly prone with properties located immediately behind the beach crest. Natural sediment transport along the beach, combined with localised tidal flows had created an accretion of gravel at the entrance to Chichester Harbour. This presented a hazard to shipping, with Chichester Harbour Conservancy (CHC) keen to maintain navigable water. Havant Borough Council, responsible for the coastal protection, initiated discussions in order to combine the dredging of the harbour entrance with the renourishment of their beach. The beneficial reuse of this material (a total of 75,000m³) had several advantages: no sediment was lost from the system; no disposal at sea; it was a very cost effective solution (saving approx 60% compared to sourcing from the nearest licensed area) as the dredging cycle time was very short and two clients benefited from the single operation. Boskalis Westminster is keen to promote the reuse of dredged material, with several similar schemes completed to date.
Felixstowe Coastal Protection Scheme
This contract, awarded in July 2011, comprised beach recharge, rock structures, timber structures and concrete works.The works awarded to Westminster included 80,000m3 of new beach material and the construction of eighteen rock groynes. Initially the groynes were to be built during two separate campaigns, however the rate of construction was sufficient to allow the completion of all eighteen by November 2011.
Gas Pipeline Project 2nd Interconnector
Capital dredging and backfilling of marine landfall trenches at Ross Bay in Dumfries and Galloway in Scotland and Gormanston, County Meath, Ireland including all associated hydrographic survey works, pre-dredge, interims, post-dredge, pulling wire lay survey, post lay surveys and post backfill survey.The Boskalis Westminster scope of work comprised the installation of both Landfalls and included the following: Landfall works in Scotland and Ireland – Marine Survey procedure Mobilisation of dredging plant Dredging of the landfall trenches to lines and levels as specified Backfilling pipeline landfall trench following pipe installation Demobilisation