Abstract: The invention relates to a riser pipe installation that comprises a flexible duct of the non-bound type, the duct being vertically arranged between a mechanical connection with a submerged buoy at the stub on the one hand, and a mechanical connection with the seabed at the bottom on the other hand, wherein fluid connections are provided at the stub and at the bottom for connecting the riser pipe with surface equipment on the one hand and bottom equipment on the other hand; the bottom of the pipe is located at a depth of at least 1000 m where it is submitted to a computable maximum reverse bottom effect F, while the buoy is oversized in order to generate at the bottom of the riser pipe a reaction tension T higher than at least 50% or even 100% of the computable maximum reverse bottom effect F applied at the bottom of the pipe.

Abstract: The invention relates to a riser pipe installation that comprises a flexible duct of the non-bound type, the duct being vertically arranged between a mechanical connection with a submerged buoy at the stub on the one hand, and a mechanical connection with the seabed at the bottom on the other hand, wherein fluid connections are provided at the stub and at the bottom for connecting the riser pipe with surface equipment on the one hand and bottom equipment on the other hand; the bottom of the pipe is located at a depth of at least 1000 m where it is submitted to a computable maximum reverse bottom effect F, while the buoy is oversized in order to generate at the bottom of the riser pipe a reaction tension T higher than at least 50% or even 100% of the computable maximum reverse bottom effect F applied at the bottom of the pipe.