Patent ID: 9359829
Filing Date: 2016-06-07
CPC Classification: E21B

Claim Text:
1. A riser assembly for transporting fluids from a sub-sea location, comprising: a riser comprising at least one segment of flexible pipe, the riser having a first end for connection to a floating facility and a further end; at least one buoyancy element connected to a portion of the riser for enabling the portion of the riser to form a hog bend configuration and an adjacent portion of the riser to form a sag bend configuration; a weight chain suspended from the at least one buoyancy element, the weight chain extending from the at least one buoyancy element at the hog bend portion of the riser towards a sea bed, said weight chain being sufficiently long such that at least a portion thereof rests on the sea bed; and a ballast module connected to a further portion of the riser between the first end of the riser and the at least one buoyancy element, such that the ballast module is spaced apart from the at least one buoyancy element and such that in an initial deployment position, the ballast module is provided at least partially in the sag bend portion of the riser; wherein in the initial deployment position, the at least one buoyancy element has a positive buoyancy that provides an upwards force, and the ballast module has a negative buoyancy that provides a downwards force, and the positive buoyancy at least partially offsets the negative buoyancy; and wherein the ballast module is positioned such that if the positive buoyancy is reduced, the riser assembly moves to a position where the ballast module is increasingly supported by the floating facility.