Client: Large Norwegian Operator
Location: Norwegian Continental Shelf

Two mature fields in the NCS optimizes reservior drainage through remote subsea installations. Subsea installations has historically lower ability for testing and verification of well barriers.


Horizontal subsea wells on two different fields, suffered from failure in key valves in the XMT. Eventual maintenance or risk reducing measures has high cost potential due to the remoteness of the installations. The detailed design on the XMTs showed some differences in the barrier structure and the operator required knowledge of how to deal with this type of failures in well integrity management. The wells were planned to be shut in for workover planned to be one year after failure.

Workover: 20 days per well

  • Production loss field 1: 23 000 bbl per 20 days
  • Production loss field 2: 16 500 bbl per 20 days


Exprosoft solutions:

  • Subsea XMT & well barrier risk assessment
  • Evaluation of proposed risk reducing measures
  • Probability-based picture of possible incidents


  • Evaluation of risk for well/XMT designs with failed valve
  • Evaluation of risk reducing measures
  • Fact-based decision continue production

Estimated value of USD 40 million

WellMaster have the essential data for input to the QRA. In these cases, the QRAs used in decision support have led to increased production of 650 - 700 MNOK over a period of 18 months.

Large Norwegian Operator

Well Integrity Section Leader