Facility having fanned seabed-to-surface connections

An installation of bottom-to-surface connections, the installation comprising a plurality of bottom-to-surface connections arranged in a fan from a common floating support to a plurality of undersea pipes resting on the sea bottom, said bottom-to-surface connections comprising at least:

• 1) a first number k of at least 2 first bottom-to-surface connections, each referred to as a first bottom-to-surface connection and forming a first hybrid tower, each comprising:
• 1a) a first rigid pipe consisting in a first vertical riser having its bottom end fastened to a first base anchored to the sea bottom and connected to a first undersea pipe resting on the sea bottom, and with its top end tensioned in substantially vertical manner by a first float that is immersed in the subsurface, to which the first pipe is connected;
• and
• 1b) a diving first flexible connection pipe providing the connection between said floating support and the top end of said first riser, said first flexible pipe being attached at the level of a side of said floating support, two successive attachment points of said first flexible pipe being spaced apart from each other, and two virtual vertical planes containing respectively two of said successive first flexible connections pipes at rest, being arranged angularly relative to each other at a first angle αi with i=1 to k, the various vertical planes of the various ones of said first flexible connection pipes intersecting substantially at a common point C0 in a horizontal section plane;
• and
• 2) a second number m of at least one second bottom-to-surface connection, each second bottom-to-surface connection forming a second hybrid tower comprising:
• 2a) a second rigid pipe consisting in a rising column comprising a second vertical riser or an SCR type catenary second rigid pipe, with the bottom end thereof connected to a second undersea pipe resting on the sea bottom and with the top end tensioned by a second buoyancy element immersed in the subsurface, to which the second pipe is connected;
• and
• 2b) a second flexible connection pipe providing the connection between said floating support and the top end of said second rigid pipe, each of said second flexible pipes passing via a trough fastened to a said first float, thereby defining two diving portions of second flexible pipe on respective sides of said first float, the attachment point of each said second flexible pipe on said side being situated in the proximity of the attachment point of said first flexible connection pipe with said first float supporting said second flexible pipe.