Fairing and method

Patent metadata

Field	Value
Publication number	US-2016102783-A1
Application number	US-201314893790-A
Country	US
Kind code	A1
Filing date	Jul 3, 2013
Priority date	Jul 3, 2013
Publication date	Apr 14, 2016
Grant date	—

Abstract

A fairing device for the reduction of vortex-induced vibrations or motions, and for minimizing the drag about a substantially cylindrical element immersed in a fluid medium, comprising; a fairing rotatably mounted about the cylindrical element, the fairing comprising a shell with a mainly cylindrical cross-sectional shape with an outer diameter (D) following the outer diameter of the cylindrical element from an upward stagnation point of 0 degrees to at least +/−90 degrees, and which at +/−90 degrees continues as two fin-like portions in an aft direction, whereby the fin-like portions are convexly curved aft of +/−90 degrees thus tapering towards each other and are defining a tail end opening or gap less than the fairing standoff height. A method for mounting, storage, and deployment of the fairing device is also disclosed.

First claim

1 . A fairing device for the reduction of vortex-induced vibrations or motions and reduction of drag about a substantially cylindrical element immersed in a fluid medium, comprising:
a fairing rotatably mounted about the substantially cylindrical element, the fairing comprising a shell with a mainly cylindrical cross-sectional shape with an outer diameter (D) following the outer diameter of said cylindrical element from an upward stagnation point of 0 degrees to at least +/−90 degrees, and which at +/−90 degrees continues as two fin-like portions in an aft direction, wherein the fin-like portions are convexly curved aft of +/−90 degrees thus tapering towards each other and defining a tail end opening less than the fairing standoff height; and the fin-like portion on a first side is dimensionally different than the fin-like portion on a second opposing side thus forming an asymmetric cross-section.

2 . The fairing device of claim 1 , comprising two fin-like portions in the aft direction defining a chord length (C) on each side; wherein the chord length (C) on a first side is dimensionally different than the chord length (C) on a second opposing side;
wherein the chord length (C) on a given side can be dependent on either the length of the fin-like portion and/or the angle and/or the shape of a fin-like portion in the aft direction; and wherein the chord length (C) may be changeable at any one location or plurality of locations of either side of the fairing, thus forming an asymmetric cross-section, along the span length of the fairing.

3 . The fairing device of claim 1 , wherein the tail end opening constitutes more than 80% of the fairing standoff height during deployment.

4 . The fairing device of claim 1 , wherein said tail end opening constitutes a range of between 80% and 100% of the fairing standoff height during deployment.

5 . The fairing device of claim 1 , wherein the tail end opening is 80% or less than the fairing standoff height during deployment.

6 . The fairing device of claim 1 , wherein the chord length ratio (C/D) is 1.4 or less during deployment.

7 . The fairing device of claim 1 , wherein the fairing device can be stored in one shape but which after deployment can be actuated to a second shape; wherein said second shape provides VIV-reducing properties.

8 . The fairing device of claim 1 , wherein during storage, the fin-like portions aft of +/−90 degrees are held in close proximity to the cylindrical element.

9 . The fairing device of claim 1 wherein the ends of the fin-like portions do not overlap.

10 . The fairing device of claim 1 , wherein said fin-like portions comprise at least one shape-fixation device connected to the inside of the fin-like portions of the fairing device, wherein said at least one shape fixation device further comprise(s) foldable sections for conforming to said cylindrical element, and means for holding said at least one shape-fixation device in place.

11 . The fairing device of claim 10 , wherein the at least one shape-fixation device(s) comprise(s) a hinge and the means for holding said at least one shape-fixation device in place is a locking pin.

12 . The fairing device of claim 1 , wherein said cylindrical element comprises at least one hinged shape-fixation device(s) connected to the exterior of the cylindrical element, wherein said at least one hinged shape-fixation device(s) being outwards extendable to come into contact and conform to the shape of the inner side of said fin-like portions of the fairing device and held in place by means of grooves located on the inner side of said fin-like portions of the fairing device.

13 . The fairing device of claim 1 , wherein the inner side of said fin-like portions of said fairing device comprises grooves for securing at least one insertable shape-fixation device.

14 . The fairing device of claim 1 , wherein the cylindrical element is a marine riser.

15 . A method for the mounting, storage and deployment of fairing devices for the reduction of vortex-induced vibrations or motions and minimization of drag about substantially cylindrical elements immersed in a fluid medium,
characterized by the following steps: a) creating a plurality of joint sections prepared for storage by mounting fairing devices around respective cylindrical elements, wherein said fairing devices include fin-like portions which are held in close proximity around the cylindrical elements; b) connecting joint sections together prior to deployment into said fluid medium; c) actuating said fairing device, thus bringing said fin-like portions out from said close proximity around the cylindrical elements; and d) immersing a string comprising a plurality of connected joint sections into a fluid medium.

16 . The method of claim 15 , further comprising:
applying at least one shape-fixation device inside the fairing device along an axial direction by unfolding at least one hinged shape-fixation device or devices from between the cylindrical element and the fairing device; and securing and locking the said shape fixation device or devices to the fairing device and to the cylindrical element by means of a locking pin.

17 . The method of claim 16 , further comprising:
wherein applying at least one shape-fixation device inside the fairing device along the axial direction by unfolding at least one hinged shape-fixation device or devices from between the cylindrical element and the fairing device; and securing and locking the said shape-fixation device or devices to the fairing device and to the cylindrical element by means of grooves within the inside of the fairing device.

18 . The method of claim 15 , further comprising:
applying at least one shape-fixation device inside the fairing device along an axial direction by inserting at least one shape-fixation device into the inside of the fairing device along the axial direction; and securing and locking the said shape-fixation device or devices to the fairing device and to the cylindrical element by means of grooves within the inside of the fairing device or with locking pins.

19 . The method of claim 15 , wherein the step of immersing is performed prior to the step of actuating.

20 . The method of claim 19 , wherein said step of actuating is performed by means of an ROV.

21 . The method of claim 15 , wherein the fairing device is an asymmetric fairing device.

22 . The method of claim 15 , wherein the fairing device is a symmetric fairing device.

23 . The method of claim 15 , wherein the cylindrical element is a marine riser.

Assignees

• Statoil Petroleum As

Inventors

• Skaugset Kjetil

Classifications

• F16L1/15

  vertically · CPC title

• F15D1/10

  around bodies of solid material · CPC title

• B63B2021/504

  comprising suppressors for vortex induced vibrations · CPC title

• E21B17/01

  Risers · CPC title

• B63B21/663

  Fairings · CPC title