Reeling of tight fit pipe

If it would be possible to install Tight Fit Pipe by means of reeling, it would be an attractive new option for the exploitation of offshore oil and gas fields containing corrosive hydrocarbons. Tight Fit Pipe is a mechanically bonded double walled pipe where a corrosion resistant alloy liner pipe is mechanically fitted inside a carbon steel outer pipe through a thermo-hydraulic manufacturing process. Reeling is a fast method of offshore pipeline installation where a pipe is spooled on a reel, which is positioned on a vessel. The vessel subsequently sails to the offshore location where the pipe is unwound, straightened and deployed to the seabed. However, reeling of Tight Fit Pipe is not yet proven technology. The reeling process imposes high plastic strains (due to bending) in the pipe, which may cause unacceptable liner pipe wrinkling and Tight Fit Pipe ovalisation. This PhD project aimed to make a contribution to the possible development of the installation of Tight Fit Pipe by means of the reeling method. The focus of this research was on the initiation and the degree of liner pipe wrinkling as well as the degree of ovalisation occurring during the spooling-on phase of the reeling process, both theoretically and experimentally; the latter by performing full scale bending tests on 12.75 inch outer diameter Tight Fit Pipe. One of the test results indicates that a higher mechanical bending strength decreases liner pipe wrinkling and makes the Tight Fit Pipe more suitable for reeling. However, test results also show that the mechanical bonding strength for the Tight Fit Pipe tested was significantly reduced, irrespective of whether a high or a low initial mechanical bonding strength had been used prior to spooling-on. These findings justify further research into this phenomenon as the eventual mechanical bonding strength after reeling installation may be vital for its anticipated application during operation.Civil Engineering and Geoscience