Offshore

DEME is a global solutions provider in the offshore oil, gas and renewables industry. We have an unrivalled track record in the transport and installation of foundations, turbines, inter-array cables, export cables and substations for offshore wind farms. In the oil & gas industry we are experts in landfalls and civil works, rock placement, heavy lift, umbilicals and installation and decommissioning services. By operating a high-tech and versatile fleet of vessels we offer flexible solutions for the most complex offshore energy projects.

Our extensive project portfolio includes foundations for offshore wind farms, the construction of jetties, mooring facilities, quay walls and bridges, amongst many others.

We have the experience and skills needed to transport and install these enormous structures and the specialist vessels capable of handling them. We have a state-of-the-art fleet, consisting of a wide range of self-propelled, DP2 installation and heavy lift jack-up vessels with an unrivalled combination of exceptionally high transport, load and crane capacity.
 

Large diameter piles
Drilling and hammering large and XL diameter piles in challenging offshore conditions requires the right equipment to achieve precision accuracy. As well as a modern fleet of advanced vessels, we have the cranes, frames and systems, casing, hammering and drilling equipment including innovative XL offshore subsea drills, which can be constructed tailormade to the size and weight of the piles, making new step forwards in the offshore wind industry.
 

Gravity Based Foundations
With decades of experience, our highly skilled teams are also experts in Gravity Based Foundations, which are placed on top of a specifically prepared and levelled bed. Soft soil improvement techniques strengthen the ground bearing capacity of a particular area and make it fit for the installation of heavy cranes, terminals and other infrastructure. Techniques depend on the soil conditions and vary from vibro compaction, over vibro stone columns and soil mixing, to grouting and mixing with stabilising additives.

Suction pile technology
We also specialise in suction pile anchors and foundations through our subsidiary SPT Offshore. With the growing trend of increasingly strict environmental regulations, suction pile technology offers a silent and vibration free installation method, hence no expensive noise mitigation measures or shutdowns are required. Vessel time offshore is substantially reduced, thereby reducing CO2 and NOx emissions. Suction pile anchors are also interesting for the floating offshore wind industry.

We have the specialist knowledge, experience, tools and techniques that are required to supply and install high voltage submarine power cables to build an infield cable network at a windfarm, an export cable connection between a windfarm and the shore or even an interconnector between two countries.

We can manage the complete construction process, including the supply of the cables, accessories and cable protection systems, execution of seabed clearance and route preparation, pre-lay dredging, , trenching, cable laying, post-lay burial and protection of crossings and construction of landfalls. After installation, we carry out termination & testing of the cables, prior to taking the cables into use. DEME has an unmatched track record in the submarine power cable installation field. We installed the 467 km export cables at the Hornsea One offshore wind farm in the UK, the longest AC offshore wind export cable project ever installed. The Modular Offshore Grid project in Belgium, where we were responsible for the EPCI scope of 85 km submarine power cables, was delivered months ahead of schedule. Further, we have installed the inter-array cables of Thorntonbank, Northwind, Rentel, Merkur, Seastar and Mermaid Offshore Wind Farms. With the goal to reduce cable installation time and costs, we ensure our cable laying and trenching equipment is deployed as efficiently as possible. Cable burial works at the Rentel offshore wind farm for example, were optimised with our CBT 1100 trenching tool.

Most advanced cable installation vessel in the world

Our DP3 cable installation and multipurpose vessel 'Living Stone' proves to be a game-changer with its 10,000- tonne cable capacity and cutting-edge dual-lane cable system. The innovative dual-lane cable installation system can install one cable while fully preparing the second one on deck. 

Further, there are many innovative features, such as a quadrant slack control system and upending frame to minimize the risks wrt maintaining cable integrity during lay, cable buffer systems to facilitate 2nd end pull-in of cables by eliminating the need for vessel movements, a cut and seal station, a CPS Storage and handling system which reduces manual handling onboard and a universal jointing container, which is compliant with all types of cables and repair joint designs. These truly innovative systems have resulted in a vessel capable of minimising the risk of damaging the cable, whilst increasing the vessel's workability and improving production rates and at the same time reducing costs for the offshore wind industry.

We have an unrivalled track record in offshore wind turbine installation. To date, more than 2,700 WTGs of all types and sizes have been successfully installed by our experts, including the next generation mega turbines. We have worked on some of the largest wind farms in the industry and those that are furthest from the shore, and in the deepest waters.

As each project is carried out in different seabed and weather conditions, DEME has in-depth knowledge, built up over decades, to draw upon when faced with a new challenge. We also use this expertise to lead the market as a developer of pioneering new designs for installation equipment.

EPCI projects

We have the specialist installation vessels, equipment and people and can perform all aspects of a wind farm project in-house, from the initial seabed preparation, to the turbine and substation installation to the inter-array and export cables. We provide turnkey solutions to ensure that clean energy is generated as soon as possible.

DEME provides a full package of geoscience services to both the renewables industry and the oil & gas sector. We have experts specialised in offshore geotechnical and geological site investigations, geophysical marine and environmental surveys and deep-sea engineering services.
 

Integrated studies

We have the dedicated equipment and vessels to perform site investigations at wind farms, oil & gas platforms or along cable routes. Our highly-skilled specialists can provide integrated studies that combine a geotechnical site investigation and environmental impact assessment with installation monitoring, foundation and/or burial monitoring and environmental monitoring, for example. This enables our customers to get a true understanding of the site conditions and the possible implications for their projects.
 

Seabed clearance

We can also provide seabed clearance campaigns for mitigating the risks for the project and personnel working on the future site caused by the presence of Unexploded ordnance, wrecks, cables, boulders etc.

DEME has decades of experience in the field of constructing landfalls. Landfall projects for the installation of offshore pipelines, cables and umbilicals have taken us all over the world, executing projects for major pipe-laying contractors and operators. As a full solutions provider, we manage the entire spectrum of activities, including seabed preparation, trenching, pipe pulling and backfilling. 

Depending on the landfall working area and environmental guidelines, the most suitable technique is selected. DEME has an extensive track record in the various landfall techniques such as the conventional beach approach, directional drilling or microtunnelling. Different options can also be provided for the pipe pulling from onshore or offshore winches, by using an onshore sheave block from a lay barge or by a controlled surface tow.

To complement the activities around the landfalls, we also operate in deeper waters performing trenching, backfilling and pre-sweeping services, which are often required to protect, stabilise and maintain the integrity of offshore pipelines.
We provide tailored solutions for every type of coastline in the world that are designed to have a minimum impact on the local environment.

Directional drilling and microtunnelling

We are a frontrunner in the execution of complex, long-distance and large-diameter directional drilling works. In general, horizontal directional drilling and microtunnelling are an environmentally harmless and efficient solution for installing cables, pipelines and other services in ports, rivers, airports and offshore. This method allows traffic or any other activity to continue without disruption during the drilling process and ensures minimum impact on the ground surface area (i.e. beach, nature reserve, etc.).

As a renowned specialist, DEME has a considerable track record in the execution of complex open cut shore approaches, directional drilling and microtunnelling works: long-distance and large-diameter. We can devise and execute tailored solutions for every type of coastline in the world. And we always aim to mitigate the impact on the local environment.

Offshore civils

Our civil division is specialised in the engineering and construction of jetties, trestles, marine terminals, mooring and berthing dolphins and in/outtake structures. Again, the Group synergies provide all the required logistical support and a large fleet of equipment. We serve a wide range of clients in the mining, oil & gas, power generation and marine sectors.

Working in coastal waters requires both strength and powerful tools to the resist forces of nature, yet at the same time a very limited draught when working close to the beach. To serve this unusual combination in the most efficient way, DEME Offshore has a diverse fleet including formidable dredgers - capable of operating in deep and shallow waters - jack-up barges and land-based equipment.

Many of the oil and gas installations around the world are reaching the end of their productive life. Decommissioning these offshore installations presents a major challenge from a safety, environmental, technological, as well as an economical perspective.
 

Integrated approach

DEME provides an integrated approach to installation and decommissioning, always working to the very highest safety and environmental standards. Our extensive portfolio of services covers the entire decommissioning process from early planning and engineering, through to removal, transport, onshore disposal and recycling.
 

Fleet of specialised vessels & equipment

With our flexible fleet of jack-up, DP2 installation and heavy lift vessels, as well as our specialised equipment, we can provide tailor-made and cost-effective solutions that are suitable for the specifics of each location.

Floating offshore wind involves building wind turbine generators on top of floating moored structures, instead of foundations fixed to the seabed. This means that offshore wind farms can be developed in much deeper waters than was previously possible, which opens up new areas for deployment around the world. While floating platforms have been used in the oil and gas industry for more than 50 years, the technology for floating wind is still maturing but we expect the costs to come down quickly over the next decade, as a result of larger scale wind farms and a significant increase in the size of wind turbines.

DEME is a frontrunner in FOW

DEME is a pioneer in this sector and is already involved in two floating projects, which use different technologies. For Equinor ASA we have performed the front-end engineering and design (FEED) study on the Hywind Tampen project in Norway. This project consists of 11 floating concrete spar foundations to be deployed off the coast of Norway. The scope of the contract was to develop and optimise the design and construction methodology for the foundations, including the secondary steel outfitting, mooring arrangement and project execution strategy. In Belgium, we are part of the MPVAqua consortium, developing a cost-competitive concept for the floater structure to support large, offshore floating PV solutions.

What is our expertise?

• Engineering
• Full EPCI contracting 
• Design and Engineering
• Mooring installation
• Cable installation
• Wind Turbine Generator installation
• Logistic services/base port management

Partnerships

Membership FWO, WindEurope FOW Committee