U.S. patent application number 12/527058 was filed with the patent office on 2010-06-17 for vortex induced vibration suppression systems and methods.
Invention is credited to Donald Wayne Allen, Stephen Paul Armstrong, David Wayne McMillan, Janet Kay McMillan, Christopher Steven West.
Application Number | 20100150662 12/527058 |
Document ID | / |
Family ID | 39690503 |
Filed Date | 2010-06-17 |
United States Patent
Application |
20100150662 |
Kind Code |
A1 |
Allen; Donald Wayne ; et
al. |
June 17, 2010 |
VORTEX INDUCED VIBRATION SUPPRESSION SYSTEMS AND METHODS
Abstract
A system comprising a subsea structure defining an interior of
the system, the structure subject to a water current; a sleeve
exterior to the subsea structure, covering at least a portion of an
outside surface of the subsea structure; and a vortex induced
vibration suppression device exterior to the sleeve.
Inventors: |
Allen; Donald Wayne;
(Richmond, TX) ; Armstrong; Stephen Paul;
(Houston, TX) ; McMillan; David Wayne; (Deer Park,
TX) ; McMillan; Janet Kay; (Deer Park, TX) ;
West; Christopher Steven; (Pearland, TX) |
Correspondence
Address: |
SHELL OIL COMPANY
P O BOX 2463
HOUSTON
TX
772522463
US
|
Family ID: |
39690503 |
Appl. No.: |
12/527058 |
Filed: |
February 13, 2008 |
PCT Filed: |
February 13, 2008 |
PCT NO: |
PCT/US08/53784 |
371 Date: |
January 5, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60890140 |
Feb 15, 2007 |
|
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Current U.S.
Class: |
405/216 |
Current CPC
Class: |
F15D 1/10 20130101; B63B
2021/504 20130101; E02B 17/0017 20130101; B63B 21/502 20130101 |
Class at
Publication: |
405/216 |
International
Class: |
E02D 5/60 20060101
E02D005/60 |
Claims
1. A system, comprising: a subsea structure defining an interior of
the system, the structure subject to a water current; a sleeve
exterior to the subsea structure, covering at least a portion of an
outside surface of the subsea structure; and a vortex induced
vibration suppression device exterior to the sleeve.
2. The system of claim 1, wherein the subsea structure is selected
from an umbilical, a riser, and a tendon.
3. The system of claim 1, wherein the sleeve comprises an exterior
surface having a Young's modulus of at least 2 GPa.
4. The system of claim 1, wherein the vortex induced vibration
suppression device comprises a fairing or a helical strake.
5. The system of claim 1, wherein the subsea structure comprises an
exterior surface having a Young's modulus less than 2 GPa.
6. The system of claim 1, wherein the sleeve is buoyant in water,
the system further comprising a collar connected to the subsea
structure above the sleeve, the collar adapted to retain the sleeve
in an axial location along the subsea structure.
7. The system of claim 1, wherein the sleeve is negatively buoyant
in water, the system further comprising a collar connected to the
subsea structure below the sleeve, the collar adapted to retain the
sleeve in an axial location along the subsea structure.
8. The system of claim 1, wherein the sleeve comprises one or more
ledges extending exterior to the sleeve, for example
circumferential ledges.
9. The system of claim 8, wherein the vortex induced vibration
suppression device comprises one or more shoulders adapted to
interface with the one or more ledges.
10. The system of claim 1, further comprising a plurality of
sleeves.
11. The system of claim 10, further comprising a plurality of
vortex induced vibration suppression devices exterior to the
plurality of sleeves.
12. The system of claim 11, further comprising a collar between two
adjacent vortex induced vibration suppression devices.
13. A method, comprising: installing a subsea structure in a body
of water, wherein the subsea structure is subject to one or more
water currents; installing at least one sleeve exterior to the
subsea structure, covering at least a portion of an outside surface
of the subsea structure; and installing at least one vortex induced
vibration suppression device exterior to the sleeve.
14. The method of claim 13, further comprising: installing at least
one collar exterior to the subsea structure, the collar adapted to
retain the fairing and/or the sleeve in an axial location along the
subsea structure.
15. The method of claim 13, wherein the sleeve comprises an
exterior surface having a Young's modulus of at least 2 GPa.
16. The method of claim 13, wherein the subsea structure comprises
an exterior surface having a Young's modulus less than 2 GPa.
17. The method of claim 13, wherein the sleeve is installed on the
subsea structure before the subsea structure is installed in the
body of water.
18. The method of claim 13, wherein the vortex induced vibration
suppression device is installed on the subsea structure after the
subsea structure is installed in the body of water.
Description
FIELD OF THE INVENTION
[0001] This invention is related to vortex induced vibration
suppression systems that can be attached to flexible structures to
reduce drag and/or vortex induced vibration (VIV).
BACKGROUND OF THE INVENTION
[0002] Whenever a bluff body in a fluid environment, such as a
cylinder, is subjected to a current in the fluid, it is possible
for the body to experience vortex-induced vibrations (VIV). These
vibrations may be caused by oscillating hydrodynamic forces on the
surface, which can cause substantial vibrations of the structure,
especially if the forcing frequency is at or near a structural
natural frequency.
[0003] Drilling for and/or producing hydrocarbons or the like from
subterranean deposits which exist under a body of water exposes
underwater drilling and production equipment to water currents and
the possibility of VIV. Equipment exposed to VIV may include
structures ranging from the smaller tubes of a riser system,
anchoring tendons, hoses, umbilicals, and other flexible
members.
[0004] Umbilicals as used herein are defined to be a non-exclusive
example of a marine element subject to VIV. Generally an umbilical
system is used for establishing communication between the surface
and the bottom of a water body. The principal purpose of the
umbilical is to provide a fluid, electrical, and/or optical flow
path between a surface vessel and a subsurface structure.
[0005] There are generally two kinds of water current induced
stresses to which elements of a umbilical system may be exposed.
The first kind of stress as mentioned above is caused by
vortex-induced alternating forces that vibrate the underwater
structure in a direction perpendicular to the direction of the
current. These are referred to as vortex-induced vibrations (VIV).
When water flows past the structure, vortices are alternately shed
from each side of the structure. This produces a fluctuating force
on the structure transverse to the current. These vibrations can,
depending on the stiffness and the strength of the structure and
any welds, lead to unacceptably short fatigue lives. The second
type of stress is caused by drag forces which push the structure in
the direction of the current due to the structure's resistance to
fluid flow. The drag forces may be amplified by vortex induced
vibrations of the structure. For instance, an umbilical that is
vibrating due to vortex shedding will disrupt the flow of water
around it more so than a stationary umbilical. This results in
greater energy transfer from the current to the umbilical, and
hence more drag.
[0006] Many methods have been developed to reduce vibrations of sub
sea structures. Some of these methods to reduce vibrations caused
by vortex shedding from subsea structures operate by stabilization
of the wake. These methods include streamlined fairings, wake
splitters and flags. Streamlined or teardrop shaped, fairings that
swivel around a structure have been developed that almost eliminate
the shedding or vortexes. Other conventional methods to reduce
vibrations caused by vortex shedding from sub sea structures
operate by modifying the boundary layer of the flow around the
structure to prevent the correlation of vortex shedding along the
length of the structure. Examples of such methods include the use
of helical strakes around a structure, or axial rod shrouds and
perforated shrouds.
[0007] U.S. Pat. No. 5,984,584 discloses a fairing system for
protecting multiple, parallel, bundled but separate cylindrical
elements deployed in offshore applications. The fairing system
deploys a plurality of elongated fairing surface elements foldable
about an axis with a connection system joining the elongated edges
of the fairing surface elements in a folded manner about the axis.
A plurality of thrust bearings are orthogonally connected across
the fairing surface elements at each axial end and an axially
extending circular rotational surface is defined by the interior of
each of the folded fairing surface elements and a transverse edge
of the thrust bearings connected thereto. This rotational surface
has a diameter which circumscribes the multiple bundled cylindrical
elements. A plurality of clamps interconnect the bundled,
cylindrical elements and a bearing collar on the axial ends of the
clamps is provided to receive the thrust bearings of the axial ends
of the fairing elements. U.S. Pat. No. 5,984,584 is herein
incorporated by reference in its entirety.
[0008] U.S. Pat. No. 7,070,361 discloses an apparatus for
suppressing vortex induced vibrations on a marine element of a
riser system wherein the riser system comprises at least one
umbilical element. Systems comprising and methods of using said
apparatus to suppress vortex induced vibrations. The apparatus,
systems, and methods comprise module elements which provide: i) a
surface around a marine element for installing VIV suppression
devices; and ii) passages for housing the at least one umbilical
element. U.S. Pat. No. 7,070,361 is herein incorporated by
reference in its entirety.
[0009] Referring now to FIG. 1, surface structure 102 is in body of
water 100. Surface structure 102 is connected to subsurface
structure 103 at seabed 108 by connector member 104, such as an
umbilical, cable, or tendon. Current 110 encounters connector
member 104. To protect connector member 104 from vibration caused
by current 110, fairings 114 have been installed. One or more
collars (not shown) may be installed between adjacent fairings.
[0010] When VIV suppression devices are installed on umbilicals or
other flexible structures, there is a danger that the structure
will be damaged during the installation procedure. Each VIV
suppression device installation around a structure may damage the
structure, for example, if the ROV or other installation tool cuts
or crimps the structure, runs into or dislodges the structure, and
other damage as can be imagined by a person of skill in the
art.
[0011] There is a need in the art for improved apparatus and
methods for suppressing VIV.
[0012] There is a need in the art for apparatus and methods for
suppressing VIV that do not suffer from the disadvantages of the
prior art.
[0013] There is a need in the art for apparatus and methods for
providing VIV suppression to umbilical systems and other flexible
elements and for providing protection to the flexible elements.
[0014] There is a need for systems and methods of installing VIV
suppression devices to flexible elements without damaging the
flexible elements.
[0015] These and other needs will become apparent to those of skill
in the art upon review of this specification, including its
drawings and claims.
SUMMARY OF THE INVENTION
[0016] In one aspect, the invention provides a system comprising a
subsea structure defining an interior of the system, the structure
subject to a water current; a sleeve exterior to the subsea
structure, covering at least a portion of an outside surface of the
subsea structure; and a vortex induced vibration suppression device
exterior to the sleeve.
[0017] In another aspect, the invention provides a method
comprising installing a subsea structure in a body of water,
wherein the subsea structure is subject to one or more water
currents; installing at least one sleeve exterior to the subsea
structure, covering at least a portion of an outside surface of the
subsea structure; and installing at least one vortex induced
vibration suppression device exterior to the sleeve.
[0018] Advantages of the invention may include one or more of the
following:
[0019] improved apparatus and methods for suppressing VIV;
[0020] apparatus and methods for suppressing VIV that do not suffer
from the disadvantages of the prior art;
[0021] apparatus and methods for providing VIV suppression to an
umbilical or other flexible elements and for providing protection
to the flexible elements;
[0022] systems and methods of installing VIV suppression devices to
flexible elements without damaging the flexible elements;
and/or
[0023] systems and methods of installing VIV suppression devices to
subsea structures without damaging the structure.
BRIEF DESCRIPTION OF THE FIGURES
[0024] FIG. 1 illustrates an oil and/or gas production system.
[0025] FIG. 2a illustrates an oil and/or gas production system.
[0026] FIG. 2b illustrates an oil and/or gas production system.
[0027] FIG. 3a illustrates an oil and/or gas production system.
[0028] FIG. 3b illustrates a cross-sectional view of the oil and/or
gas production system of FIG. 3a.
[0029] FIG. 4 illustrates an oil and/or gas production system.
[0030] FIG. 5a illustrates an oil and/or gas production system.
[0031] FIG. 5b illustrates an oil and/or gas production system.
DETAILED DESCRIPTION
[0032] Referring now to FIG. 2a, system 200 is illustrated. System
200 includes surface structure 202 near the surface of the water,
which is attached to connector member 204. Connector member 204 is
also connected to subsurface structure 203 near seafloor 208.
Exterior to connector member 204 near seafloor 208, collar 220 has
been installed. Exterior to connector member 204, sleeves 222 have
been installed, which rest on collar 220.
[0033] Referring now to FIG. 2b, fairings 214 have been installed
exterior to sleeves 222. Sleeves 222 allow fairings 214 to be
installed with less risk of damaging connector member 204. Fairings
214 act to reduce drag and/or vortex induced vibration acting on
connector member 204 due to current 210. Fairings 214 and/or
sleeves 222 may be heavier than water so that they sink to rest on
collar 220.
[0034] Referring now to FIG. 3a, system 300 is illustrated. System
300 includes surface structure 302 near the surface of the water,
which is attached to connector member 304. Connector member 304 is
also connected to subsurface structure 303 near seafloor 308.
Exterior to connector member 304 near surface structure 302, collar
320 has been installed. Exterior to connector member 304, sleeves
322 have been installed, which rest on collar 320. Fairings 314
have been installed exterior to sleeves 322. Sleeves 322 allow
fairings 314 to be installed with less risk of damaging connector
member 304. Fairings 314 act to reduce drag and/or vortex induced
vibration acting on connector member 304 due to current 310.
Fairings 314 and/or sleeves 322 may be lighter than water so that
they float to rest on collar 320.
[0035] Referring now to FIG. 3b, a cross-sectional view of system
300 is shown. Connector member 304 defines an interior of the
system. Sleeve 322 has been installed exterior to connector member
304. Fairing 314 has been installed exterior to sleeve 322. Space
330 is defined between the exterior of sleeve 322 and the interior
of fairing 314, which allows fairing 314 to weathervane with
varying current directions.
[0036] Referring now to FIG. 4, system 400 is illustrated. System
400 includes surface structure 402 near the surface of the water,
which is attached to connector member 404. Connector member 404 is
also connected to subsurface structure 403 near seafloor 408.
Exterior to connector member 404 near subsurface structure 403,
collar 420 has been installed. Exterior to connector member 404,
sleeves 422 and sleeves 424 have been installed, which rest on
collar 420. Fairings 414 have been installed exterior to sleeves
422 and sleeves 424. Sleeves 424 may be installed between every
about 1 to about 10 sleeves 422. Sleeves 424 have flange 426.
Flange 426 has a larger diameter than an interior diameter of
fairing 414, which acts to provide a bearing surface that the
fairing 414 above and/or the fairing below can rotate on. Flange
426 may be copper to retard marine growth.
[0037] Sleeves 422 and sleeves 424 allow fairings 414 to be
installed with less risk of damaging connector member 404. Fairings
414 act to reduce drag and/or vortex induced vibration acting on
connector member 404 due to current 410. Fairings 414, sleeves 424,
and/or sleeves 422 may be lighter than water so that they float to
rest on collar 420.
[0038] Referring now to FIG. 5a, system 500 is illustrated. System
500 includes surface structure 502 near the surface of the water,
which is attached to connector member 504. Connector member 504 is
also connected to subsurface structure 503 near seafloor 508.
Exterior to connector member 504 near surface structure 502, collar
520 has been installed. Exterior to connector member 504, sleeve
522 has been installed, near subsurface structure 503. Fairings 514
have been installed exterior to sleeve 522 with tool 530 having
attachment mechanism 532, for example arms, to grip fairings 514.
Sleeve 522 allows fairings 514 to be installed with less risk of
damaging connector member 504. Fairings 514 act to reduce drag
and/or vortex induced vibration acting on connector member 504 due
to current 510. Fairings 514 may be lighter than water so that they
float to rest on collar 520.
[0039] Referring now to FIG. 5b, system 500 is illustrated. System
500 includes surface structure 502 near the surface of the water,
which is attached to connector member 504. Connector member 504 is
also connected to subsurface structure 503 near seafloor 508.
Exterior to connector member 504 near subsurface structure 503,
collar 520 has been installed. Exterior to connector member 504,
sleeve 522 has been installed, near surface structure 502. Fairings
514 have been installed exterior to sleeve 522 with tool 530 having
attachment mechanism 532, for example arms, to grip fairings 514.
Sleeve 522 allows fairings 514 to be installed with less risk of
damaging connector member 504. Fairings 514 act to reduce drag
and/or vortex induced vibration acting on connector member 504 due
to current 510. Fairings 514 may be heavier than water so that they
float to rest on collar 520.
[0040] Fairings may be replaced with strakes, shrouds, wake
splitters, tail fairings, buoyancy modules, or other devices as are
known in the art. Suitable sleeves, suitable collars, and suitable
devices to install exterior to sleeves, and methods of their
installation are disclosed in U.S. patent application Ser. No.
10/839,781, having attorney docket number TH1433; U.S. patent
application Ser. No. 11/400,365, having attorney docket number
TH0541; U.S. patent application Ser. No. 11/419,964, having
attorney docket number TH2508; U.S. patent application Ser. No.
11/420,838, having attorney docket number TH2876; U.S. Patent
Application No. 60/781,846 having attorney docket number TH2969;
U.S. Patent Application No. 60/805,136, having attorney docket
number TH1500; U.S. Patent Application No. 60/866,968, having
attorney docket number TH3112; U.S. Patent Application No.
60/866,972, having attorney docket number TH3190; U.S. Pat. No.
5,410,979; U.S. Pat. No. 5,410,979; U.S. Pat. No. 5,421,413; U.S.
Pat. No. 6,179,524; U.S. Pat. No. 6,223,672; U.S. Pat. No.
6,561,734; U.S. Pat. No. 6,565,287; U.S. Pat. No. 6,571,878; U.S.
Pat. No. 6,685,394; U.S. Pat. No. 6,702,026; U.S. Pat. No.
7,017,666; and U.S. Pat. No. 7,070,361, which are herein
incorporated by reference in their entirety.
[0041] Suitable methods for installing sleeves, collars, and other
devices to install exterior to sleeves, are disclosed in U.S.
patent application Ser. No. 10/784,536, having attorney docket
number TH1853.04; U.S. patent application Ser. No. 10/848,547,
having attorney docket number TH2463; U.S. patent application Ser.
No. 11/596,437, having attorney docket number TH2900; U.S. patent
application Ser. No. 11/468,690, having attorney docket number
TH2926; U.S. patent application Ser. No. 11/612,203, having
attorney docket number TH2875; U.S. Patent Application No.
60/806,882, having attorney docket number TH2879; U.S. Patent
Application No. 60/826,553, having attorney docket number TH2842;
U.S. Pat. No. 6,695,539; U.S. Pat. No. 6,928,709; and U.S. Pat. No.
6,994,492; which are herein incorporated by reference in their
entirety.
[0042] The collars and/or sleeves may be installed on the connector
member before or after the connector member is placed in a body of
water.
[0043] The sleeves may be made of a high strength material having a
Young's Modulus (or modulus of elasticity) of at least about 2 GPa,
for example at least about 5 GPa, for example at least about 10
GPa, for example at least about 25 GPa, for example at least about
50 GPa, for example at least about 75 GPa, for example at least
about 100 GPa, for example at least about 200 GPa.
[0044] The sleeves may be round, or have some ovality or a fairing
shape.
[0045] The sleeves, collars, fairings and/or other devices exterior
to the sleeves may have a clamshell configuration, and may be
hinged with a closing mechanism opposite the hinge, for example a
mechanism that can be operated with an ROV.
[0046] Collars may be placed between adjacent fairings, or between
every 2 to 10 fairings. The collar may be a copper ring.
[0047] Fairings may be provided with copper plates on their ends to
allow them to weathervane with adjacent fairings or collars.
[0048] Fairings may be partially manufactured from copper.
[0049] A biodegradable spacer may be placed between adjacent
fairings to keep them from binding and allow them to weathervane
after the spacer has degraded.
[0050] The connector member 404 may be made of a low strength
material and/or have a low strength material as a covering, for
example having a Young's Modulus (or modulus of elasticity) of less
than about 2 GPa, for example less than about 1 GPa, for example
less than about 0.5 GPa, for example less than about 0.25 GPa, for
example less than about 0.1 GPa.
[0051] In one embodiment, there is disclosed a system comprising a
subsea structure defining an interior of the system, the structure
subject to a water current; a sleeve exterior to the subsea
structure, covering at least a portion of an outside surface of the
subsea structure; and a vortex induced vibration suppression device
exterior to the sleeve. In some embodiments, the subsea structure
is selected from an umbilical, a riser, and a tendon. In some
embodiments, the sleeve comprises an exterior surface having a
Young's modulus of at least 2 GPa. In some embodiments, the vortex
induced vibration suppression device comprises a fairing or a
helical strake. In some embodiments, the subsea structure comprises
an exterior surface having a Young's modulus less than 2 GPa. In
some embodiments, the sleeve is buoyant in water, the system
further comprising a collar connected to the subsea structure above
the sleeve, the collar adapted to retain the sleeve in an axial
location along the subsea structure. In some embodiments, the
sleeve is negatively buoyant in water, the system further
comprising a collar connected to the subsea structure below the
sleeve, the collar adapted to retain the sleeve in an axial
location along the subsea structure. In some embodiments, the
sleeve comprises one or more ledges extending exterior to the
sleeve, for example circumferential ledges. In some embodiments,
the vortex induced vibration suppression device comprises one or
more shoulders adapted to interface with the one or more ledges. In
some embodiments, the system also includes a plurality of sleeves.
In some embodiments, the system also includes a plurality of vortex
induced vibration suppression devices exterior to the plurality of
sleeves. In some embodiments, the system also includes a collar
between two adjacent vortex induced vibration suppression
devices.
[0052] In one embodiment, there is disclosed a method comprising
installing a subsea structure in a body of water, wherein the
subsea structure is subject to one or more water currents;
installing at least one sleeve exterior to the subsea structure,
covering at least a portion of an outside surface of the subsea
structure; and installing at least one vortex induced vibration
suppression device exterior to the sleeve. In some embodiments, the
method also includes installing at least one collar exterior to the
subsea structure, the collar adapted to retain the sleeve in an
axial location along the subsea structure. In some embodiments, the
sleeve comprises an exterior surface having a Young's modulus of at
least 2 GPa. In some embodiments, the subsea structure comprises an
exterior surface having a Young's modulus less than 2 GPa. In some
embodiments, the sleeves are installed on the subsea structure
before the subsea structure is installed in the body of water. In
some embodiments, the vortex induced vibration suppression device
are installed on the subsea structure after the subsea structure is
installed in the body of water.
[0053] Those of skill in the art will appreciate that many
modifications and variations are possible in terms of the disclosed
embodiments, configurations, materials and methods without
departing from their spirit and scope. Accordingly, the scope of
the claims appended hereafter and their functional equivalents
should not be limited by particular embodiments described and
illustrated herein, as these are merely exemplary in nature.
* * * * *