Wintershall Noordzee B.V. installed a new remote platform at L6-B as a gas production tie-back to L8-P4. L6-B is a remote and unmanned gas well unit. Utilising a dry-tree design, all control, power and metered injection for the two wells will be via the 19.5-km control umbilical between the new satellite platform L6-B and the operational gas platform L8-P4. 

The umbilical forms the entire link between the remote platforms, supplying and controlling all functions and ensuring continual feedback and monitoring of L6-B. The umbilical supplies all the necessary input data, control and feedback to eliminate the usual day-to-day requirement of direct human contact. The umbilical was installed from L8-P4 first end to second end pull-in at L6-B remote end. Both platforms are located in Dutch territorial waters in the North Sea. The umbilical was connected/pulled in to L6-B via a J-tube and internal conductor to the L6-B topside - TUTA. The umbilical will be installed from L8-P4 - first end with pull-in to topside deck via a J-tube, laid in corridor separate from the 8-inch pipeline between L8-P4 and L6-B.

FACTS AND FIGURES

  • Water depth 30-35 meters
  • Challenging North sea conditions.
  • Challenging soft seabed.
  • Fast-track project, with a short lead-time between award and installation – Feb 2014, July/Aug installed.
  • Stepped phase process of pull-in, laying and burial ops.
  • Completed on time, with no incidents.
  • Umbilical loaded quickly and safely.
  • Umbilical length 19.5 km.
  • Burial scope of single pass burial of umbilical minimum requirement of 1m TOC (top of cover).

SCOPE OF WORK

  • Prepare project planning for Boskalis’ scope of work.
  • Survey work, including a pre-burial, as-laid and post-burial survey.
  • Perform route engineering and installation engineering to optimize the performance of the installation scope, including a detailed burial assessment study (BAS).
  • Prepare platform on L8-P4 and L6-B.
  • Define umbilical length together with the client.
  • Umbilical load-out at DUCO Newcastle (UK) onto the installation vessel Ndurance.
  • Hang-off of umbilical end.
  • Crossing 36-inch live gas pipeline Callantsoog.
  • Pull-in at L6-B & L8-P4 platforms – direct from vessel as part of SIM-OPS.
  • Mobilize and demobilize all installation spreads for Boskalis’ scope.
  • Provide engineering support during the offshore umbilical installation, including burial.
  • Provide QHSE management for Boskalis’ scope.

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