The Joint Industry Project DEA(E)-96 (Shell, Amoco, Entreprise Oil, Hess, Mobil, BG Technologies) completed in 2000, has proved the feasibility of longitudinally folded pipe, rounded by fluid pressure, but also revealed the collapse resistance reduction of the solid wall technology, after the cycle of folding-unfolding, when compared to a non deformed pipe of the same grade and weight.
The Joint Industry Project DEA-163 Phase 1 (Total, Wintershall, GDFSuez, Petrobras), completed in 2012, enhanced the concept in demonstrating that high pressure performances can be achieved by using a sandwich wall instead a solid wall on the CoilFlat CT Liner technology (MonoBore Drilling), and test of samples exceeded the collapse resistance of the non deformed pipe of the same grade and weight.
From theses combined successes, the CoilFlatLine pipe-in-pipe flowline/pipeline system was designed to first: break the 20” diameter limitation of Reel-Lay technology, second: extend deeper the use of rigid pipe and third: scale down the reel size for easier transportation resulting in a substantial reduction of the DP reel-laying vessel size.
CoilFlatLine needs only one tie-in weld or mechanical connection every 700 to 1,000 meters (2.100 ft to 3,300 ft) and permit the use of 500-700 Mpa (80-100 ksi) steel, to push deeper the physical limitation of rigid subsea trunkline and transcontinental gas transmission lines.
Additionally the CoilFlatLine pipe-in-pipe configuration offers built-in insulation and the centralizing ancillary pipes offers heating, glycol injection and monitoring while the flat reeled configuration permits the use of a high efficiency tensioning system.
As an example of immediate application, CoilFlatLine can provide a game-changing approach to the Oman-India Pipeline Project in 3,500 m (11,700 feet) of water at a fraction of the present estimated cost.