InterMoor used their multi-string caisson cutting tool with Scimitar centralizing technology to successfully cut a single leg caisson for Prime 8 Offshore in the West Cameron area of the Gulf of Mexico as part of the decommissioning efforts for the structure.
First, the inner strings were cut at 350 ft. depth below the mud line.
Next, after another contractor plugged the well at that depth, the grouted multi-string conductor was cut at about 25 ft. below the mudline passing through a thickness of up to 10 inches of steel and grout. Finally, the outer caisson was cut. Three cuts were completed – one multi-string and two single string cuts. The outer most caisson was 60” diameter at the seabed. The inner strings measured from 26” to 13 3/8” ID.
The 40,000-psi water jet abrasive cutting tool can be configured to perform either internal or external cutting of piles, caissons or platform legs. In this case it was used internally. It uses ultra high pressure water with garnet. The air injection system ensures a very low environmental footprint and a lower cost than other cutting tools.
Datasheets for InterMoor’s cutting tools are available here.