Slipover jacket removal, KSA
Scope of Work
James Fisher Decommissioning were contracted to carry out internal abrasive water jet cutting on pile foundations to facilitate the removal of 3 slipover jackets in the Arabian Gulf. This was required to allow the installation of replacement jackets.
The first location was a 6 legged jacket structure, with a cut required at the base of each leg. The second 2 locations were 2 legged structures similar in design. The initial strategy per the scope of work was to remove these 50m tall 2 legged jackets in 4 sections with cuts at 4 elevations. However, close to the mobilisation date this approach changed and it was decided to remove the structure with single cuts BML, requiring late adjustments to the tooling scope supplied. Water depth was between 39 and 46m at all locations
Scope of Supply
JF Decom scope of supply included the provision of engineering, project management, equipment and offshore personnel for the internal cutting of the existing jackets. An ultra high pressure internal abrasive water jet cutting spread was provided complete with 3S cut verification system for internal cutting of the piles. A 12” Air lift tool was also supplied along with necessary pumping equipment for the removal of soil plugs within the jacket legs.
Results and Benefits
The scope of work was completed safely and on time, with all jacket legs successfully cut in one pass. Due to the height of the jackets the air lift tool joints were required to be assembled to a new maximum operating length of 55m, with the tool operating successfully at the additional height throughout the campaign.