Aqua Milling® Wax Removal from Riser

Scope:

Pipetech was tasked to clear a suspected blockage inside GD riser 31 on Gannet Alpha. Access was to be via the pig launcher door and negotiate round a “Y” junction into the riser.

Challenges:

A specialist cleaning team working along side platform production technicians, who ran a total length of 270 meters of Aqua Milling® line, utilising a step down cutting nozzle. Once a clear path was established and the line had been retrieved, a polishing run was carried out to clear internal diameter of wax deposits. The polishing run to 270 meters ran at 1 foot per minute to ensure total effective cleaning of the pipe wall internal. All waste deposits were collected via a scale collector and stored in vacuum skips for disposal.

Achievements:

Successful cleaning and recovery of waste from 270 meters negotiating 11 bends.

All waste material fully contained from pipeline to waste handling skips with no loss of containment and/or environmental impact

Aqua Milling of 6” line negotiating a diverter valve.

Recovery of waste from subsea pipeline that included a vertical lift of 120 meters

Benefits:

Safety

Fully contained remotely operated jetting nozzle prevented work party and platform personnel coming into contact with potentially hazardous waste and high pressure water.

Environmental

All waste material recovered to Aqua Milling entry point and removed from scale collector via vacuum pump to closed vacuum skips for specialist disposal.

Flexibility

Workscope carried out utilizing the minimum of deck space as possible.