Pipelaying

Patent metadata

Field	Value
Publication number	US-10544880-B2
Application number	US-201815912270-A
Country	US
Kind code	B2
Filing date	Mar 5, 2018
Priority date	Mar 4, 2013
Publication date	Jan 28, 2020
Grant date	Jan 28, 2020

Abstract

A mudmat for a subsea pipeline accessory has a body with an accessory support structure arranged to lie underneath and support an accessory. At least one foundation element attached to the body is movable from a stowed position at least partially under the accessory support structure into a deployed position extending laterally from the accessory support structure after overboarding the accessory from a vessel and before landing the accessory on the seabed. Two or more foundation elements may be deployed simultaneously in laterally-opposed directions transverse to the longitudinal axis of a pipe that supports the accessory.

First claim

The invention claimed is:

1. A mudmat for a subsea pipeline accessory, the mudmat comprising:
a body having an accessory support structure comprising a top plate arranged to lie underneath and support an accessory; and
at least one foundation element attached to the body and movable from a stowed position at least partially under the accessory support structure into a deployed position extending laterally from the accessory support structure,
the or each foundation element being supported for translation relative to the body during movement into the deployed position,
wherein the body is hollow underneath the top plate to define a space in which the or each foundation element is accommodated in the stowed position; and
wherein the body has a length that defines a longitudinal direction and a width that is less than the length, and the or each foundation element extends from under the accessory support structure in a widthwise direction during movement from the stowed position into the deployed position.

2. The mudmat of claim 1 , wherein the or each foundation element is fully under the accessory support structure when in the stowed position.

3. The mudmat of claim 1 , wherein the or each foundation element and the body have laterally-extending rail elements that cooperate to support the foundation element for sliding lateral movement relative to the body.

4. The mudmat of claim 3 , and having at least two foundation elements each supported by laterally-extending rail elements for sliding lateral movement relative to the body.

5. The mudmat of claim 1 , wherein the or each foundation element is supported to lie in a first plane in the stowed position and to remain in the same plane during movement into the deployed position.

6. The mudmat of claim 1 , wherein, in their stowed positions, first and second foundation elements lie in side-by-side relation under the accessory support structure.

7. The mudmat of claim 1 , further comprising a drive mechanism acting between the or each foundation element and the body to drive movement of the or each foundation element into the deployed position.

8. The mudmat of claim 1 , wherein the body has a length that defines a longitudinal direction to be aligned with a pipe axis in use and a width that is less than the length, and the or each foundation element extends from under the accessory support structure in a widthwise direction during movement from the stowed state into the deployed state.

9. The mudmat of claim 8 , wherein first and second foundation elements extend from under the accessory support structure in opposed widthwise directions.

10. The mudmat of claim 1 , wherein the body provides additional foundation area in use when the mudmat is laid upon the seabed.

11. The mudmat of claim 1 , wherein the or each foundation element substantially comprises an intrinsically lighter material than the material of the body, such that the material of the or each foundation element is lighter per unit volume than the material of the body.

12. The mudmat of claim 1 , wherein the or each foundation element is a substantially flat panel in outline shape with a thickness less than 10% of its length.

13. The mudmat of claim 1 , further comprising at least one temporary locking system to secure the or each foundation element temporarily in the stowed position.

14. The mudmat of claim 1 , further comprising at least one permanent locking system to secure the or each foundation element in the deployed position.

Assignees

• Subsea 7 Ltd

Inventors

• Du david

Classifications

• F16L1/16

  on the bottom · CPC title

• F16L1/24

  Floats; Weights · CPC title

• F16L1/20 Primary

  Accessories therefor, e.g. floats or weights · CPC title