Dolphin Overhauls Cooling Package for Jack-Up Rig in 12-Day Yard Stay

A jack-up drilling rig operating in the Arabian Gulf came in for a scheduled yard stay with its cooling water exchanger package showing reduced performance from seawater-side biofouling and early-stage corrosion on several coolers. Every day the rig spends in the yard beyond its planned stay is a day it is not earning day-rate offshore, which made the 12-day window a hard commercial constraint on the whole scope.

Dolphin's marine service crew mobilised dockside to strip, inspect, clean and recondition the full cooling package within the rig's fixed 12-day yard window — every day beyond that window carried a direct day-rate cost to the client. Work was sequenced across multiple coolers in parallel rather than one at a time, so the critical path ran through the slowest individual repair rather than the sum of all of them.

Coolers showing early-stage corrosion were assessed against remaining wall thickness rather than replaced wholesale, keeping the scope — and the cost — proportionate to what the inspection findings actually justified, while still meeting the class-society condition requirements for the rig's next survey.

The overhauled package was pressure-tested and reinstalled before the rig returned to service, with class-society-ready documentation provided to support the rig's next survey — work that stayed inside the yard window the client had budgeted for from the outset.