Oil and gas-Subsea Risers and Flowlines


Oandg Subsea Risers 460X189

With a detailed knowledge and understanding of subsea risers and flowlines, we help clients to optimise the design and performance of these complex systems, ensuring that capital and operational costs can be minimised without compromising safety requirements.

Delivering expertise in dynamic subsea systems

Subsea pipelines are often highly complex systems, which have to operate for prolonged periods in harsh environments. Their use for the transfer of hydrocarbons means that these systems are safety-critical, with potential for significant threats including environmental impact and injury to personnel. Through supporting clients in the design, assessment and analysis of their pipeline assets, we help to ensure that they remain safe through their lifespan.

Subsea risers are typically dynamic systems which must be engineered to withstand variable hydrodynamic loading, and to interface with a fixed or floating rig; while subsea flowlines are static systems which interface with the non-uniform properties of the seabed, and must tolerate cyclic operational effects from variations in temperature and pressure. Our systems engineering approach delivers understanding of the complex multiple interfaces that influence the performance of subsea risers and flowlines. We use this understanding to deliver high-quality results that meet clients’ requirements without compromising on the required performance of the global system.

We have experience of a wide range of subsea pipeline systems, including:

  • Exploration and production systems
  • Fixed and floating rigs
  • Shallow and deep water systems, at worldwide locations
  • Rigid, flexible and composite pipelines
  • Wellhead, conductor and casing structural response.

Our experienced subsea engineers can also draw upon the wider pool of specialist engineers within Frazer-Nash, so that skills, experience and best practice can be transferred from other highly regulated engineering disciplines and applied to provide solutions to the subsea sector. We offer a tailored approach that provides clarity and value, enabling you to make critical decisions with the best possible understanding of the situation. Our approach will only ever be as complex as is absolutely necessary.

Our skills and services

  • Concept design and innovation
  • Method development and research
  • Definition of functional requirements and independent review of supplier capabilities
  • Simulation and modelling
  • Global pipeline design and analysis
  • Local component design and analysis
  • Non-linear structural assessment
  • Fatigue analysis, including Vortex-Induced Vibration (VIV) and Flow-Induced Vibration (FIV)
  • Coupled analysis of vessel, riser and mooring line interaction
  • Engineering Critical Assessment (ECA)
  • Design assurance
  • Independent review and verification of third party analysis
  • Risk identification and management
  • Safety engineering, including hazard and operability studies (HAZOP) and Failure Modes, Effects, and Criticality Analysis (FMECA)
  • Accident, incident and near-miss investigations
  • Definition and optimisation of integrity management requirements, and specification of equipment
  • Asset management support: equipment, integration and realisation
  • Whole-life costing
  • Evaluation of life extension for ageing infrastructure.