The Breagh gas field could be shut until next year after further problems were discovered at the processing plant handling its output.
Initially it had been thought the field would be shut in for a fortnight to allow repair work to be carried out, but now that has been signficantly extended.
Project partners Sterling said preliminary estimates for production resuming on the field would be six to eight weeks, with an investigation into the root causes of the latest problems now underway.
“The initial physical investigations have identified areas of immediate repair which are being addressed on an urgent basis,’ said Sterling chief operating officer John Rapach.
“We are concerned at this occurrence and are working closely with our partner RWE Dea to ensure a thorough understanding of the event.
“Once the root cause investigation is complete, a full statement on both progress of repairs, and definitive work scope and schedule will be made.”
Investigation work on the inlet to the Teesside gas processing plant has discovered serious damage to pipelines, thermo wells and pipe junctions linking the plant with the field.
The shut-in to the field, initially confirmed last week, comes less than a month after the field finally started production – two months behind schedule.
The field, discovered in 1997, is expected to produce around 112million cubic feet of gas per day once fully operational.