Riser Assembly and Umbilical Pull In - Katmai, US Gulf of Mexico

Scope

Fieldwood Energy Inc. planned to tie back the Katmai Field Development to the Tarantula Platform, surrounded by seawater 479 ft>. The award is for the deepwater Katmai Field Development in the US Gulf of America’s Green Canyon 40. One Subsea will provide subsea production systems (SPS). Subsea 7 will supply subsea umbilicals, riser, and flowline systems (SURF). They requested Conbit to support the subsea operations working from the platform. 

The project work scope included the installation and operation of: 

• 8” Production Riser assembly, comprising clamps and six sections 
• 16” J-Tube assembly, comprising clamps and five sections
• umbilical pull-in through the 16” J-Tube assembly
  

Riser and J-tube

To support the J-tube clamps and pipe segments alongside the platform jacket structure and the riser's subsea installation, Conbit provided several lift lines in the installation area. The installation procedure involved a handover from the Subsea7 Pegasus vessel crane to lift lines that Conbit provided. This is to position all the parts alongside the jacket. 

Divers then finalized the installation procedures. The execution of the works took place in close coordination between vessel cranes, diving teams, ROV operations, and the daily platform operations.

Umbilical and winches

After installing the J-tube, the team changed the Conbit equipment setup to prepare for the umbilical pull-in. They positioned a winch and 27 ton capacity A-frame above the J-tube. Conbit used its modular A-frame equipment for this. Conbit used a total of five different winches with lift line capacities between 11-27 ton. The water depths required winch wires in 600-1700 ft. To safeguard the lift operations and protect the umbilical against overstressing, Conbit's engineers continuously monitored the load and pay-in/pay-out of all the winches.