Patent ID: 6672804
Filing Date: 2004-01-06
Classification: E21B

Abstract:
Apparatus for holding and guiding a riser relative to a floating support, the apparatus including guide means enabling said riser to slide along its longitudinal axis ZZâ€² and guiding lateral displacements thereof in a horizontal plane XXâ€², YYâ€² perpendicular to said longitudinal axis of the riser, the apparatus being characterized in that it comprises joint means secured to said floating support and enabling:a) said riser to rotate about a horizontal axis XXâ€², YYâ€² perpendicular to the longitudinal axis ZZâ€² of said riser within the limit of a cone having a half-angle at the apex that is less than or equal to 10Â°, said horizontal axis and said apex of the cone being situated substantially at the center of the riser and level with the midplane of the zone along the longitudinal axis ZZâ€² where said joint means are situated; and b) said riser to slide along the longitudinal axis ZZâ€² and to be guided in its lateral displacements in a plane XXâ€², YYâ€² substantially perpendicular to said longitudinal axis of the riser, and said joint means comprise: first friction pads mounted on a pad support enabling said pads to pivot about respective axes perpendicular to said longitudinal axis of said riser ZZâ€²; and said first pads co-operating with one of wheels and second friction pads, such that said one of said wheels and said second pads bear against said riser, and enable it to slide, and said riser comes to bear against said first pads only when said wheels and said second pads are moved under the effect of lateral displacements of said riser.