Turret mooring buoy system

Patent metadata

Field	Value
Publication number	US-10814938-B2
Application number	US-201816620604-A
Country	US
Kind code	B2
Filing date	Jun 21, 2018
Priority date	Jun 22, 2017
Publication date	Oct 27, 2020
Grant date	Oct 27, 2020

Abstract

A mooring buoy system releasably connects risers and anchor lines to a turret of a floating structure, and includes: a buoyant body carrying the risers, which extend to a subsea hydrocarbon well; anchor line connectors, for connecting anchor lines to the buoyant body, each anchor line having one end connected to a connector and the opposing end to the seabed; and a reconnection wire running through a channel coinciding with a center line of the buoyant body, connectable to each anchor line below the buoyant body at some distance from the anchor line connectors through anchor line connection sections on one end and includes a stopper and winch wire connection arrangement on the other end. Also disclosed is a method for pulling up risers and anchor lines, for releasably attaching the risers and anchor lines, as well as a method for constructing a mooring buoy.

First claim

The invention claimed is:

1. A mooring buoy system for releasably connecting one or more risers and anchor lines to a turret of a floating structure, wherein the buoy comprises:
a buoyant body for carrying the one or more risers, which extend to a subsea hydrocarbon well;
a number of anchor line connectors, for connecting a number of anchor lines to the buoyant body such that each anchor line has one end connected to one of the connectors and the opposing end is connected to the seabed; and
a reconnection wire,
wherein in an equilibrium state the buoyancy of the buoyant body is equal to a mass of the buoyant body plus a suspended weight of the one or more risers and a pulling force of the anchor lines,

wherein a main section of the reconnection wire runs through a channel coinciding with a center line of the buoyant body, and is connectable to each of the anchor lines below the buoyant body at some distance from the anchor line connectors through anchor line connection sections of the reconnection wire on one end and comprises a stopper and winch wire connection arrangement on the other end, situated on the opposite side of the buoyant body from where the anchor line connectors are located.

2. The mooring buoy system according to claim 1 , wherein the anchor line connectors are at a non-zero radial distance from the center line of the buoyant body.

3. The mooring buoy system according to claim 2 , wherein a length of the reconnection wire is such that the anchor line connector sections form a slack when the stopper and winch wire connection arrangement is in contact with a side opposite of the side of the buoyant body where the anchor line connectors are connected to anchor lines and the reconnection wire anchor line connection sections are attached to the respective anchor lines at a connection point.

4. The mooring buoy system according to claim 1 , wherein a length of the reconnection wire is such that the anchor line connector sections form a slack when the stopper and winch wire connection arrangement is in contact with a side opposite of the side of the buoyant body where the anchor line connectors are connected to anchor lines and the reconnection wire anchor line connection sections are attached to the respective anchor lines at a connection point.

5. The mooring buoy system according to claim 1 , wherein the reconnection wire is connectable to the anchor lines at a distance from the anchor line connection to the buoyant body, such that a short anchor line section, being the anchor line section between the connection point and the buoyant body, is tension released when the reconnection wire is pulled up, thereby creating distance between the stopper and winch wire connection arrangement and the buoyant body.

6. The mooring buoy system according to claim 5 , wherein the release of tension on the anchor lines comprises the removal of the anchor line weight from the force counteracting the buoyancy so as to exert a reduced force onto the buoyant body.

7. A vessel for offshore operations and comprising a turret mooring system, wherein the turret mooring system is connected to the anchor lines and one or more risers through the mooring buoy system according to claim 1 .

8. A method for pulling up one or more risers and a number of anchor lines, for releasably attaching the risers and anchor lines in a turret of a hull of a vessel, by means of a mooring buoy system, and wherein the buoy comprises a buoyant body, carrying the one or more risers, which extend to a subsea hydrocarbon well, and a number of anchor lines, having an anchor line connector connected to the buoyant body on one end and a seabed connection on their other end; and a reconnection wire which runs through a channel coinciding with a center line of the buoyant body, and is connected to each of the anchor lines, at a connection point at some distance from the anchor line connectors, through anchor line connection sections, and which comprises a stopper and winch wire connection arrangement on the other end, situated on the opposite side of the buoyant body from where the anchor line connectors are located, comprising the steps of:
attaching a winch wire from a turret mooring system of the vessel to the reconnection wire of the mooring buoy system, when the buoy is in an equilibrium state in which the buoyancy of the buoyant body being equal to a mass of the buoyant body plus a suspended weight of the one or more risers and a pulling force of the anchor lines;
pulling in the winch wire, resulting in the reconnection wire pulling directly onto the anchor lines, through the center of the buoyant body, such that a section of the anchor lines between the reconnection wire connection and the anchor line connector becomes slack, reducing the suspended weight on the buoyant body;
reeling in of the winch wire such that the anchor line section between the connection point and the anchor line connector remains slack, allowing the buoyant body carrying the one or more risers to float upwards using the buoyancy force of the buoyant body only.

9. The method according to claim 8 , whereby the velocity of the reeling in of the winch wire directly controls the buoy rise-up.

10. The method for attaching one or more risers in a cavity of a turret of a vessel's hull, through use of a method according to claim 9 , comprising the steps of:
pulling up the one or more risers, whereby the reeling in of the winch wire continues until the buoyant body is received in the turret structure;
locking in of the buoyant body inside a cavity of the turret structure;
releasing the reconnection wire, such that it forms a slack below the buoyant body where it is connected to the anchor lines and the slack is removed from the section of the anchor lines between the reconnection wire connection and the anchor line connector.

11. The method for attaching one or more risers in a cavity of a turret of a vessel's hull, through use of a method according to claim 8 , comprising the steps of:
pulling up the one or more risers, whereby the reeling in of the winch wire continues until the buoyant body is received in the turret structure;
locking in of the buoyant body inside a cavity of the turret structure;
releasing the reconnection wire, such that it forms a slack below the buoyant body where it is connected to the anchor lines and the slack is removed from the section of the anchor lines between the reconnection wire connection and the anchor line connector.

12. A vessel for offshore operations and comprising a turret mooring system, wherein the turret mooring system is configured for use of the method in accordance with claim 8 .

13. A method for manufacturing a mooring buoy comprising the steps of:
providing a buoyant body, comprising a through channel in the buoyant body coinciding with a center line of the buoyant body;
installing a number of anchor line connectors on a transverse side to the through channel;
installing one or more riser connectors on the side comprising the anchor line connectors;
installing a reconnection wire through the through channel of the buoyant body, whereby the reconnection wire contains an equal number of wires to the number of anchor line connectors on the reconnection wire extremity exiting the buoyant body on the side having the anchor line connectors attached, and a stopper and winch wire connector arrangement is installed on the opposite extremity of the reconnection wire.

14. The method for manufacturing a mooring buoy according to claim 13 , further comprising the step of manufacturing the buoyant body and providing a through channel in the buoyant body coinci

Assignees

• Single Buoy Moorings

Inventors

• Daran Renaud
• Schut Xavier
• Bauduin Christian Raymond

Classifications

• B63B22/02

  specially adapted for mooring a vessel · CPC title

• B63B21/50

  Anchoring arrangements {or methods} for special vessels, e.g. for floating drilling platforms or dredgers · CPC title

• B63B22/023 Primary

  submerged when not in use (container type buoys submerged when not in use, not adapted for mooring a vessel B63B22/28; connected to turret B63B21/508) · CPC title

• B63B2022/028

  submerged, e.g. fitting into ship-borne counterpart with or without rotatable turret, or being releasably connected to moored vessel · CPC title

• B63B21/508 Primary

  connected to submerged buoy (mooring buoys per se B63B22/02) · CPC title