- Norwegian Continental Shelf
- Potential Production Loss
- Continue Producing
- Well Integrity
Background: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.
Failed XMT Valves – Shut-in or Continue Production?
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
– Subsea XMT & well barrier risk assessment
– Evaluation of proposed risk reducing measures
– Probabilitybased picture of possible incidents
- Evaluation of risk for well/XMT designs with failed valve
- Evaluation of risk reducing measures
- Fact-based decision continue production