Patent ID: 9121230
Filing Date: 2015-09-01
Classification: B63B,E21B

Abstract:
1. A seabed-to-surface riser system comprising: a group of two or more subsea riser supports each extending upwardly from a seabed anchorage to a buoyant upper end region located beneath the surface and each supporting at least one riser pipe extending from the seabed to the upper end region; and at least one jumper pipe extending from the upper end region of each riser support to a surface installation at a location above the riser support, the riser supports and the surface installation defining a flow direction of well fluids that, when the system is viewed from above, extends generally from the upper end regions of the riser supports toward the surface installation, and the surface installation being spaced horizontally from the riser supports in the flow direction; wherein: the group of riser supports is disposed to one side of the surface installation; at least outermost riser supports of the group lie on an axis transverse to the flow direction; a plurality of laterally-extending flexible lines are attached to each of the outermost riser supports, the plurality of laterally-extending flexible lines each applies mutually-opposed stabilising forces to each of the riser supports in the group of riser supports in directions transverse to the flow direction; and at least one of the laterally-extending flexible lines is a mooring line that extends from an outermost riser support of the group to the seabed, wherein a riser support of the group is connected to one or more neighbouring riser supports of the group by at least one of the laterally-extending flexible lines extending transversely with respect to the flow direction.