Two gas platforms in the Celtic Sea had reached the end of their economic life. The platforms both had limited deck space and limited crane capacity. WellGear were awarded a contract to P&A all of the platform wells with a hydraulic workover unit (14 wells in total).
WellGear mobilised a 340k Unit to the Alpha platform, followed 4 months later by a 460k unit to the Bravo platform.
The first well of the campaign did not have sufficient cement behind the production casing so a PWC operation was undertaken. 200ft of casing was perforated above the production packer and a jetting tool was run to clean up the cement behind the perforations. An 800ft cement plug was then run.
Since this was the first PWC job of the campaign the success of the operation had to be evaluated. All 800ft of cement was drilled out and CBL run to verify how effective the PWC job had been at remediating the cement behind the production casing.
The PWC was shown to have been a complete success and the well now had 200ft of continuous, laterally extensive cement behind the production casing. After confirmation of the PWC job another 800ft cement plug was run to plug the well.
The conductor and casings were drilled with WellGear's dual pinning machine and secured together with a 4" pin.
The conductor and casings were cut at the seabed and the WellGear HWU lifted the conductor by 2ft to demonstrate that it had been cut completely.
All 14 wells were successfully plugged and abandoned and the conductors were cut and pinned for later recovery.
The campaign had originally been planned with a duration of 1 year but WellGear were able to complete the final well and demobilise 2 months ahead of schedule.