Pipelines & Cables Sector
Increasing demand for offshore energy and communication is resulting in an increasingly dense network of offshore line infrastructure. Pipelines for oil and gas, and for communication and electricity cables, need protection against a variety of hazards, both natural and human. Safeguarding supplies of oil, gas or energy is the key challenge for offshore line infrastructure. Unexpected interruptions in deliveries can disrupt entire markets. Deltares works with designers, contractors and network owners to develop safe designs throughout the lifetime of the infrastructure.
Predicting seabed changes
To protect cables and pipelines against external threats such as ship’s anchors, fishing nets and dropped objects, they are often buried in the seabed. However, at many sites, morphodynamic features such as sand waves migrate over the seabed, resulting in large variations in seabed levels. Deltares has developed techniques to predict these morphodynamic seabed changes in the offshore, nearshore and landfall areas. These techniques range from data-driven methods to process-based models like Delft-3D. With DTS (Distributed Temperature Sensing) we are measuring cable temperatures and predicting cable burial depths now and for the remainder of the lifetime. For owners of networks or wind farms, this means that risks can be managed better and that they can cut monitoring and maintenance costs, as well as insurance premiums.
Smarter cable routing
Once the variation in seabed levels during the lifetime of a project is known, this information can be used to define the smartest routes for line infrastructure and the minimum required burial depth. Higher construction costs (Capital Expenditure: CAPEX) for longer cable routes or deeper cable burial can result in much lower Operational Expenditure (OPEX) due to the reduction of risks, and lower maintenance and repair costs. Deltares helps wind-farm owners to cut costs by looking at expenditure throughout the lifetime of a project.
External threats from anchors and fishnets
Ship’s anchors or fishing nets that are dragged across the sea bed pose a major threat to line infrastructure. To assess the risks for the client we perform physical model tests at different model scales; from small-scale tests in the Geocentrifuge to the large Water and Soil-Flume or Delta Flume.
Protection and freespan mitigation
Deltares has extensive expertise in cable and pipeline protection methods. Whether a cable crossing or free-span mitigation is involved, we advise our clients about a multitude of different situations where line infrastructure requires protection.
Deeper burial depths are required to prevent the exposure of line infrastructure in very morphodynamic areas. Deeper burial makes it more likely that contractors will have to dig through multi-layered soils. Deltares draws on its long experience with dredging techniques to advise about effective cable burial techniques in multi-layered soils. Combinations of jetting, ploughing and excavating are being investigated.