Multiple wellhead seals are repaired in 5 hours

Plasma® restores integrity and provides full barrier isolation

  • Client Major Operator
  • Repair Location 13 3/8" pack-off seal, tubing hanger BT seal, upper hydraulic packing/ lower moulded o-ring
  • Location North Sea
  • Nominal Bore 13 3/8 inch casing, 7 inch tubing

Challenge

A production well had been shut in pending water shut-off operations, and annular communication resulting from multiple wellhead seal failures had been identified. Diagnostic tests confirmed that the 13 3/8" pack-off seal was passing, allowing the C annulus to charge up the 13-3/8" void. In addition, the tubing hanger BT seal, upper hydraulic packing (metal-to-metal seal) and lower moulded o-ring were also passing. Pressure from the A annulus was charging up the hanger void and the tubing.

Solution

Plasma® was used to restore integrity in the 13 3/8" pack-off, the tubing hanger BT seal, the upper hydraulic packing and lower moulded o-ring, all of which required repair to provide full barrier isolation.

Outcome

After injecting Plasma® into each seal, a successful pressure test at 1,000psi for 15 minutes was performed for each injection. A subsequent series of successful 30-minute pressure build-up tests confirmed that there was zero pressure present in the 13-3/8" pack-off seal, tubing hanger BT seal and upper hydraulic packing/lower moulded o-ring. The Plasma® had restored the integrity of every passing seal in the wellhead, providing full safety case barrier isolation. With double barriers in place, the well was brought back online as soon as water shut-off operations were complete. Wellhead integrity was restored in just 5 hours.

The upside

Multiple seals were reinstated without intervention, with no requirement for a costly and time-consuming workover.

There was no risk to the operation of the well, as the solution does not affect future wellhead operations.