Shell Gumusut Kakap
Gumusut Kakap is a deepwater oil discovery in offshore Sabah, Malaysia where Sabah Shell Petroleum Company is the designated Operator. This development employs Malaysia’s first deepwater semi-submersible production system. The 44,000 t FPS is to be located about 200 km off the shore of Sabah (East Malaysia) in the South China Sea in water depth about 1,200 m. The project has allowed Shell to share deep-water expertise with Malaysian energy companies, assisting in the Malaysian government’s goal to create an offshore industry hub. The platform was built in Malaysia by Malaysian Marine and Heavy Engineering Sdn Bhd (MMHE). Boskalis was awarded a contract by MMHE for the provision of the Heavy Transport Vessel (HTV) for the load-out, float-off and tow-back package of the Project which includes the load-out of the Integrated FPS from MMHE fabrication Yard onto the HTV, Dry-transport to Desaru, Float-off, Tow-back and Re-delivery at MMHE fabrication yard. Boskalis was responsible for the load-out-, transport- and float-off engineering and execution of the Gumust Kakap FPS. This included the design of HTV grillages, skid beams and seafastening as well as the design, fabrication and delivery of a ground reaction type Buoyance Tank(BT). The scope also included the mobilization and readiness of HTV Blue Marlin, HTV ballasting during the skidded load-out operation and the provision of the marine spread required for the float-off operation and HTV and BT demobilization. HTV Blue Marlin arrived at the load-out yard end of March 2013. The fabrication yard started with the installation of the grillage required for the load-out of the FPS. The outfitting of the HTV main deck was completed mid-April. Since the draft of the FPS, once afloat, would be more than the maximum water depth over the HTV main deck, a draft reduction mechanism had to be designed. For this purpose Boskalis had designed and fabricated a Buoyance Tank (BT). This BT was designed to fit between the FPS bottom plating and the top of the HTV grillage. On the BT fabrication yard the BT was loaded onto a charted barge, transported to Pasir Gudang, where it was loaded-in for storage until the FPS was ready for the load-out. On April 16th 2013 the BT was load-out by SPMT’s onto the barge that would be used for positioning the BT between FPS bottom and HTV grillage. On May 3rd the FPS was skidded to just before the HTV (land-pull) to start the load-out the next day. As a result of the skidding system used, the tolerances were very small, which resulted in a slow skidding speed. The FPS was in its final position in the early morning of May 5th. Once in position the securing of the FPS started, the link beams were removed and the HTV de-ballasted to BT load-out conditions. On May 9th the barge with BT were moored against the HTV. The next day the load-out of the BT started and on May 11th the BT was in the correct position. HTV and BT were now prepared and tested for the dry-tow and the subsequent discharge operations. On May 14th the loaded HTV shifted from Pasir Gudang to the offload location near Desaru where it dropped anchor. Various preparatory work on the FPS and seafastening removal had to be done and on May 21st all was ready for the discharge of the FPS with the BT under it. The FPS and BT were towed off the HTV by 1 AHT and 4 inshore tugs. After this discharge the HTV de-ballasted and shifted back to the yard for main deck reinstatement. The FPS needed to be offloaded from the BT which started early morning of May 22nd by ballasting of the BT. The FPS was towed off the BT that same afternoon and re-delivered to client. The BT was de-ballasted and towed back to Pasir Gudang for reinstatement. To ensure that the FPS could achieve the required float-off draft, the BT, which is technically a ground reaction barge is required for the discharge operation. Boskalis was responsible for ensuring that the BT was designed, constructed and delivered to ensure the safe and successful execution of this complex discharge. The BT design was unique, having its own power, sophisticated ballast system, tank gauging system, ballast air compressors, hydraulics etc. which had to be thoroughly examined and dry tested before the operation. Also, ground reaction barge operations require flat hard seabed. Intensive research was carried out including bottom survey of several areas around the coast before suitable location with hard sand at required depths was found off Desaru area. The success of the project was due to the strong cooperation between all parties. The project had schedule challenges but the close working relationship between the project management teams of MMHE and Boskalis ensured that the project was still executed in a safe, operationally sound and timely manner.
Cieg GJ1 Cable repair
Channel Islands Electricity Grid, a joint venture between Jersey Electricity and Guernsey Electricity operate several interconnecting power cable systems (power and telecom) between Jersey, Guernsey and France. Both Jersey and Guernsey rely upon the services of these interconnecting power cables and as a consequence there is a demand to reduce the possible effects and impact of failure to these interconnecting power cables. Boskalis were contracted to conduct a preemptive repair replacing a section of cable including the installation two subsea joints on the Guernsey Jersey circuit, close to Havelet bay. SCOPE OF WORK Mobilisation of cable repair vessel and auxiliary equipment Mobilise cable storage pan and turntable onto transpooling barge Load spare cable from the storage pan onto the Ndurance Determine cable cut position along cable route Cut, test and seal operations Removal of sea end cable till jointing location Cut cable and joint to new cable section Lay down joint No.1 on sea bottom and lay new section of cable Recover shore end and joint both cable ends Lay down joint No.2 and omega on sea bottom Post lay ROV survey Having signed a Power Cable Maintenance Agreement (PCMA) in the summer of 2012, Boskalis maintains a long standing relationship with Channel Islands Electricity Grid (CIEG). The parties involved in the agreement have worked together to achieve a quick response method for maintaining and where necessary repairing the subsea assets that are so vital for the islands communities. In November 2014 Boskalis was instructed to mobilise for a preemptive repair after CIEG had detected a potential vulnerability in the subsea cable, which provides a power link to the Island. Extensive and detailed engineering was carried out over the Christmas and New Year period, owing to the very difficult repair area. The large tide range and strong, unpredictable currents around the shallow rocky outcrops of Havelet Bay created a number challenges during the engineering phase. Being a winter repair in the English Channel the planning for the project was critical. Mobilisation of the CLV “Ndurance” started on the 12th January with the cable being loaded from the Boskalis storage only 5 days later. The vessel arrived in Havelet bay, Guernsey on the 21st January to start the repair operations after 48 hours of DP familiarisation along the challenging route. The repair operation was broken into sections to ensure that each operation could be complete once it had been committed to. The repair was completed on schedule and to the satisfaction of all parties on the 5th February 2015. Guernsey Electricity issued a statement which commended the professionalism and efficiency of Boskalis throughout what was a challenging repair in a difficult period.
The DanTysk offshore wind farm was being built by Vattenfall and Stadtwerke München and is located west of the island of Sylt, on the German-Danish border. With 80 wind turbines in total, DanTysk provides up to 400,000 homes with green energy. Although cable activities in the German North Sea started in July 2013, it wasn’t until February 2014 that Boskalis was called in to complete termination work on the 35 cables already installed. Despite the extremely short preparation time, it proved possible to commence work within 20 days with the Boskalis Offshore DP3 vessel, Protea. At the same time, the Stemat 87 set sail to Velsen and Tonsberg to load the cable. She continued her journey to Esbjerg, where was loaded onto the installation vessel, Olympic Taurus. The installation and termination work for the remaining 53 cables was resumed in April 2014.
Anholt offshore wind farm is located between the headland of Djursland on the Jutland coast and the island of Anholt. The site covers an area of 144 km2 and is comprised of 111 monopile wind turbines and one offshore substation. INSTALLATION OF 111 CABLES IN 4 MONTHS As part of this project, Boskalis was contracted by Dong Energy to install 111 infield cables with a total length of around 154 km. Dong Energy subcontracted the cable manufacturer to supply three types of cable (150 mm2, 240 mm2 and 500 mm2), delivered by train on 89 drums and in 3 continuous lengths (500 mm2). Boskalis deployed two cable installation spreads to lay cables for the Anholt Wind Farm. The first cable installation spread was the Stemat 82, assisted by anchor handling tugs, Lydia D and Nova K. The Stemat 82 is an anchored barge equipped with a large turntable which was used to install the long cables that connect the substation to the first wind turbine in each row of the wind farm. The second installation spread consisted of a purpose-built reel drive cable installation spread that was installed on the rear deck of the DP2 offshore construction vessel, Toisa Wave. This vessel ran into port to load 9 cable drums at a time. This set-up proved to be extremely efficient, resulting in the timely completion of the cable installation scope, ahead of schedule. After each cable was installed, Boskalis used a jetting ROV to trench the cables into the seabed at a target depth of 1.5 metres. The trenching of the cable was done independently of the cable installation, using a DP2 trenching support vessel. Boskalis was also responsible for the design, supply and installation of 210 No. cable protection systems. These systems were tailor-made to suit the different cable entry configurations, such as bell mouths at the substation, J-tubeless cable entries in the monopiles, situations with or without preinstalled scour protection, etc. The cable protection systems contained a seal system which restricts the water flow in and out of the monopiles. Boskalis used local divers to activate the seals once cable installation was completed.
Boskalis was contracted by OWP Butendiek GmbH & Co. KG to supply, install and protect (by post-lay burial) the high-voltage inter-array cable at the offshore wind farm of Butendiek. This German wind farm is situated in the German Bight (Nordsea), approx. 35 km west of the island of Sylt. The 33 km2 wind farm consists of 80 wind turbines with a capacity of 3.6 MW each and a total capacity of 288 MW. The inauguration of the wind farm took place on September 8, 2015. It provides renew-able energy to approx. 370,000 households. The infield cables were loaded in one load-out at Drammen in Norway and then cut down to the correct size on site. The WTGs were connected in a grid of infield cables. 86 individual cables were installed between the turbines, including 6 redundancy cables, amounting to a total length of approximately 90 km for the infield cabling. Cable production commenced in December 2013. The cables were installed in the summer of 2014 using the Stemat Spirit. This vessel was converted to enable the handling of the long cable protection system lengths. Trenching of the cables was performed using a separate trenching spread. Termination, testing and commissioning of the 12 cable strings were carried out using in-house resources.
Malikai is a deepwater oil discovery in offshore Sabah, Malaysia where Sabah Shell Petroleum Company is the designated Operator. A floating Dry Tree Unit (DTU) will be installed over Malikai field utilizing a Tension Leg Platform (TLP) design that suits the Malikai environment. The 27,500 MT Malikai TLP is to be located about 110 km off the shore of Sabah (East Malaysia) in the South China Sea in water depth about 500 m. Boskalis was awarded a contract in 2014 for the provision of the Heay Transport Vessel (HTV) for loadout and float-off package of the Project which includes loadout of the Integrated Malikai TLP from MMHE fabrication Yard into HTV, Dry-transport to Johor Buoy, Float-off, Tow back and Re-delivery to TMJV at MMHE fabrication yard. SCOPE Loadout, Transport and Float-off Engineering Design, construct and installation of grillages, skid beams and seafastening Preparation and Mobilization of White Marlin Ballasting of the HTV during the skidded loadout operation Provision of marine spread for the float off operation Demobilization of White Marlin and reinstatement PROJECT CHALLENGES Technical challenges included the ability to adapt and successfully perform: The discharge of the TLP offshore in Desaru instead of the original location of Johor Port; The loadout of the integrated TLP ballasted instead of un-ballasted prior to loadout The outfit of a HTV in Vietnam for the first time NINA The project was executed without incident. The NINA initiative was not only inculcated within the Boskalis PMT but also with key subcontractors. CONCLUSION The success of the project was due to the strong colaboration between all parties. The loadout oper-ation had several difficult challenges; technically and operationally. However, this was all resolved through communica-tion and the close cooperation between TMJV and Boskalis, which ensured that the TLP was still loaded in a safe, operationally sound and timely manner.