Subsea Completion & Workover Risers

200+ projects conducted

2H Offshore has extensive experience in completion, intervention and workover risers, landing strings and riserless intervention systems.

These projects encompass a wide range of services, vessel types, water depths and environments including many of the most technologically challenging deepwater and HPHT (high pressure and high temperature) wells.

Riser arrangements and methods of implementation can vary considerably from one application to the next, with each presenting specific design challenges. We have worked extensively with the key interfaces and components of completion and workover riser systems, including tension lift frame, drill string compensator, surface tree, coiled tubing equipment, LRP, EDP and subsea tree. Our experience of the riser operations and equipment enables us to quickly define operating limits for existing equipment or develop new systems including joint configuration, component sizing, coupling selection and clamp design.

Key Services

  • Riser configuration and space-out
  • Wall thickness sizing and coupling selection
  • Production-annulus-umbilical interaction and clamp/guide design
  • Taper joint sizing and detailed design
  • Stack-up and tension optimisation
  • Strength and operating envelope analysis to API RP 17G and ISO 13628-7
  • Riser weak point, vessel drift-off and loss of position assessment
  • Drill string compensator and tensioner lock-up and failure assessment
  • Tree installation and intervention analysis and operating envelopes
  • Riser disconnect, recoil and hang-off analysis
  • Wave fatigue and VIV fatigue analysis
  • Marine riser mode equipment passage limitations assessment
  • BOP landing string shearing capacity assessment
  • Component engineering (connector, cased wear joint)
  • Coupling qualification testing
  • Spider, test and make-up tooling specification and design
  • Specialist component procurement management
  • Riser monitoring and integrity management
  • Operating manuals

Project Experience

  • BP – Q5000, DS-3 and other intervention riser design campaigns
  • Woodside – Management of riser data and operability assessments of 6 different intervention risers
  • Total – Akpo Detail design of drill pipe riser and supply of taper joints
  • BP – Schiehallion 7×2 5k and monobore completion riser design and analysis
  • Cameron (UK) – over 20 projects on the 5×2 10k system
  • Coflexip – Stena Seawell 6-5/8in intervention riser, North Sea
  • DSND – Botnica and Fenica intervention risers, North Sea engineering support
  • GE/SRP – HPHT (15-20 ksi, 250-350 degF) riser system design
  • Helix – over 20 studies for risers deployed from the Q4000, H534 and Q5000 vessels
  • OneSubsea – HPHT (15-20 ksi, 250-350 degF) riser system design study
  • Petrobras / Grant Prideco – Deepwater Brazil optimisation study
  • Shell – GoM multiple intervention riser and riserless campaigns
  • TOGI – 5k tool joint completion riser design
  • Total/Schlumberger – multiple studies for landing string analysis in marine riser mode