Reel lay method installs offshore pipeline by sending the pipeline from a reel mounted on a special pipeline installation vessel. Instead of connecting each joint of pipe line at an offshore location like other methods (S-lay and J-lay method), the pipeline is pre-assembled in a spool which is mounted on the deck of the reel barge. This method can lay pipe up to 16” diameter and water depth capacity for 16” pipeline is about 800 m (2,600 ft). This method cannot lay such a big size pipe because the big pipeline is not flexible enough to be rolled into a reel.
The reels can be installed either horizontal or vertical. Horizontal reel barges can do only S-lay installation; however, vertical reel barges can perform both J-lay and S-lay pipeline installation.
The reel lay method is considered to be the fastest laying method because the majority of welding and inspections are performed onshore in order to minimize time for installation. Once all pipe on the reel is laid, the barge either head back to shore of another reel or lift a new reel from a supply boat. This is dependent of each vessel.
Some of the images of reel lay barges are shown below;
Figure 1 – Vertical reel-lay barge in S-lay configuration
Figure 2 – Vertical reel-lay barge in J-lay configuration
References
James G. Speight, 2014. Handbook of Offshore Oil and Gas Operations. 1 Edition. Gulf Professional Publishing.
Trond Bendiksen, 2015. Commissioning of Offshore Oil and Gas Projects: The manager’s handbook. Edition. AuthorHouse.
Joseph A. Pratt, 1997. Offshore Pioneers: Brown & Root and the History of Offshore Oil and Gas. Edition. Gulf Professional Publishing.