Key facts
Customer: Undisclosed supermajor
Location: Central North Sea, UKCS
Well type: Subsea production gas wells
Key benefits: PWC® solution eliminated five days from the estimated operational timings
The customer’s challenge
HydraWell was asked to support the operator in a four well abandonment campaign for suspended subsea production gas wells at 115 metres water depth. A semi-submersible drilling rig was used for the campaign.
A key challenge was to ensure a quick turnaround from a planning perspective, in readiness for the offshore operations. Among the operator’s key objectives were to remove unnecessary scope, reduce costs and lower HSE exposure.
The HydraWell solution
PWC® (perforate, wash, cement) was performed on all wells, using HydraWell’s HydraHemera™ tool. This was the operator’s first deployment of the PWC® method on a subsea well. The single trip method was applied on two of the wells, while a two-trip was required on the two others.
As per defined barrier requirements, these operations delivered a 250ft annular barrier with 800ft of internal cement plug.
The result
Rock-to-rock barriers were successfully set. Compared to the operator’s previous P&A campaigns, which incorporated section milling, HydraWell’s PWC® method removed 5-6 days from the original annulus remediation timing.
The quickest PWC® operation on this sequence was 44 hours, while the rest were executed between 52 and 62 hours.
Using the PWC® method also removed multiple HSE risks including reduction of lifts, removal of swarf handling, no swarf damage to equipment and no swarf disposal.
