U.S. patent application number 14/279471 was filed with the patent office on 2014-11-20 for self-aligning subsea structures.
This patent application is currently assigned to AKER SUBSEA LIMITED. The applicant listed for this patent is AKER SUBSEA LIMITED. Invention is credited to Charles Donald LAWSON.
Application Number | 20140341656 14/279471 |
Document ID | / |
Family ID | 48746994 |
Filed Date | 2014-11-20 |
United States Patent
Application |
20140341656 |
Kind Code |
A1 |
LAWSON; Charles Donald |
November 20, 2014 |
SELF-ALIGNING SUBSEA STRUCTURES
Abstract
A subsea assembly comprises a first structure (1) including a
plurality of substantially parallel guide posts (4) and a second
structure (2) comprising a support and depending therefrom a
plurality of tubular receptacles (12) each positioned for fitment
on a respective one of the guide posts. At least one of the
receptacles includes a plurality of longitudinally disposed
semi-elliptical springs (15) disposed to engage the exterior of the
respective guide post (4) and thereby to axially centre the
receptacle with respect to the guide post. In a converse
arrangement at least one of the posts (4) carries a plurality of
longitudinally disposed semi-elliptical springs (15) disposed to
engage the interior of the respective receptacle (12) and thereby
to axially centre the receptacle with respect to the guide
post.
Inventors: |
LAWSON; Charles Donald;
(Aberdeenshire, GB) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
AKER SUBSEA LIMITED |
Berkshire |
|
GB |
|
|
Assignee: |
AKER SUBSEA LIMITED
Berkshire
GB
|
Family ID: |
48746994 |
Appl. No.: |
14/279471 |
Filed: |
May 16, 2014 |
Current U.S.
Class: |
405/195.1 |
Current CPC
Class: |
E02D 27/52 20130101;
E21B 33/035 20130101; E21B 41/10 20130101; E21B 19/24 20130101 |
Class at
Publication: |
405/195.1 |
International
Class: |
E02D 27/52 20060101
E02D027/52 |
Foreign Application Data
Date |
Code |
Application Number |
May 17, 2013 |
GB |
1309007.1 |
Claims
1. A subsea structure for deployment on a plurality of
substantially parallel guide posts comprising: a support and
depending therefrom a plurality of tubular receptacles each
positioned for fitment on a respective one of the guide posts;
wherein at least one of the receptacles includes a plurality of
longitudinally disposed semi-elliptical springs disposed to engage
the exterior of the respective guide post and thereby to axially
centre the receptacle with respect to the guide post.
2. A subsea structure according to claim 1 in which each spring
secured to a respective receptacle at one end and is adjustably
supported with respect to that receptacle at its other end.
3. A subsea structure according to claim 2 in which the said other
end of the spring is supported by a member which is captive within
the respective receptacle.
4. A subsea structure according to claim 3 in which each spring has
at each end an axially extending foot.
5. A subsea structure according to claim 1 in which there are four
springs disposed at 90.degree. degree intervals about the axis of a
receptacle, so as to provide a centring action for orthogonal
directions laterally of the respective post.
6. A subsea assembly comprising: a first structure comprising a
plurality of substantially parallel guide posts; a second structure
comprising a support and depending therefrom a plurality of tubular
receptacles each positioned for fitment on a respective one of the
guide posts; wherein at least one of the receptacles includes a
plurality of longitudinally disposed semi-elliptical springs
disposed to engage the exterior of the respective guide post and
thereby to axially centre the receptacle with respect to the guide
post.
7. A subsea assembly according to claim 6 in which each spring is
secured to a respective receptacle at one end and is adjustably
supported with respect to that receptacle at its other end.
8. A subsea assembly according to claim 7 in which the said other
end of the spring is supported by a member which is captive within
the respective receptacle.
9. A subsea assembly according to claim 8 in which each spring has
at each end an axially extending foot.
10. A subsea assembly according to claim 6 in which there are four
springs disposed at 90.degree. degree intervals about the axis of a
receptacle, so as to provide a centring action for orthogonal
directions laterally of the respective post.
11. A subsea assembly according to claim 6 in which the first
structure comprises a central post around which the said guide
posts are disposed and the second structure comprises a cooperative
part disposed for fitment over the central post.
12. A subsea structure comprising a plurality of substantially
parallel guide posts wherein, for the reception of a second
structure which comprises a support and depending therefrom a
plurality of tubular receptacles each positioned for fitment on a
respective one of the guide posts, at least one of the posts
carries a plurality of longitudinally disposed semi-elliptical
springs disposed to engage the interior of the respective
receptacle and thereby to axially centre the receptacle with
respect to the guide post.
13. A subsea structure according to claim 12 in which each spring
is secured to a respective post at one end and is adjustably
supported with respect to that post at its other end.
14. A subsea structure according to claim 13 in which the said
other end of the spring is supported by a member which is captive
within the respective spring.
15. A subsea structure according to claim 14 in which each spring
has at each end an axially extending foot.
16. A subsea structure according to claim 12 in which there are
four springs disposed at 90.degree. degree intervals about the axis
of a post, so as to provide a centring action for orthogonal
directions laterally of the respective post.
17. A subsea assembly according to claim 12 in which each of a
plurality of the receptacles includes a plurality of longitudinally
disposed semi-elliptical springs disposed to engage the exterior of
a respective guide post and thereby to axially centre the
receptacle with respect to the respective guide post.
18. A subsea assembly comprising: a first structure comprising a
plurality of substantially parallel guide posts; a second structure
comprising a support and depending therefrom a plurality of tubular
receptacles each positioned for fitment on a respective one of the
guide posts; wherein at least one of the posts carries a plurality
of longitudinally disposed semi-elliptical springs disposed to
engage the interior of the respective receptacle and thereby to
axially centre the receptacle with respect to the guide post.
19. A subsea assembly according to claim 18 in which each spring is
secured to a respective post at one end and is adjustably supported
with respect to the post at its other end.
20. A subsea assembly according to claim 19 in which the said other
end of the spring is supported by a member which is captive within
the respective spring.
21. A subsea assembly according to claim 20 in which each spring
has at each end an axially extending foot.
22. A subsea assembly according to claim 18 in which there are four
springs disposed at 90.degree. degree intervals about the axis of a
post, so as to provide a centring action for orthogonal directions
laterally of the respective post.
23. A subsea assembly according to claim 18 in which the first
structure comprises a central post around which the said guide
posts are disposed and the second structure comprises a cooperative
part disposed for fitment over the central post.
24. A subsea assembly according to claim 18 in which each of the
posts carries a plurality of longitudinally disposed
semi-elliptical springs disposed to engage the interior of a
respective receptacle and thereby to axially centre the receptacle
with respect to the respective guide post.
Description
FIELD OF THE INVENTION
[0001] This invention relates to subsea structures and to the
facilitation of alignment of those structures.
BACKGROUND TO THE INVENTION
[0002] It is known to provide an assembly of subsea structures of
which a first structure comprises a base and a plurality of
substantially parallel guide posts extending from the base and of
which a second structure comprises a support and depending
therefrom a plurality of tubular receptacles each positioned for
fitment on a respective one of the guide posts. The ordinary
purpose of such an assembly is to allow accurate mating of the
structures, for example to allow connection of a marine riser to a
subsea installation. The latter may incorporate the first structure
and include a boss which may be centrally located relative to the
guide posts. The second structure may have a cooperative part which
can engage the boss to provide connection of the marine riser to a
passageway within the boss. However, the invention is applicable to
other kinds of structures.
[0003] A general problem arises from the difficulty of causing
engagement of these and similar structures in accurate alignment.
One structure is often tilted with respect to the other and
consequently is quite liable to bind or jam. It would be desirable
to provide an assembly in which correct alignment of the posts and
receptacles were facilitated, whereby to avoid, or at least lessen
the need for, manipulation of the structures by a diver or a
remotely operated vehicle (ROV), and to allow engagement and
disengagement at greater degrees of angular or positional
misalignment.
SUMMARY OF THE INVENTION
[0004] In one embodiment the invention subsists in a subsea
structure for deployment on a plurality of substantially parallel
guide posts, comprising a support and depending therefrom a
plurality of tubular receptacles each positioned for fitment on a
respective one of the guide posts; wherein at least one of the
receptacles includes a plurality of longitudinally disposed
semi-elliptical springs disposed to engage the exterior of the
respective guide post and thereby to axially centre the receptacle
with respect to the guide post.
[0005] In another aspect the invention subsists in a subsea
assembly, comprising a first structure comprising a plurality of
substantially parallel guide posts; a second structure comprising a
support and depending therefrom a plurality of tubular receptacles
each positioned for fitment on a respective one of the guide posts;
wherein at least one of the receptacles includes a plurality of
longitudinally disposed semi-elliptical springs disposed to engage
the exterior of the respective guide post and thereby to axially
centre the receptacle with respect to the guide post.
[0006] Each spring may be secured to a respective receptacle at one
end and be adjustably secured to that receptacle at its other end.
The said other end of the spring may be supported by a member which
is captive within the respective receptacle. Each spring may have
at each end an axially extending foot. There may be four springs
disposed at 90.degree. degree intervals about the axis of a
receptacle, so as to provide a centring action for orthogonal
directions laterally of the respective post. However, other numbers
of springs may be suitable.
[0007] In a specific example all the receptacles may have springs
as aforesaid.
[0008] In another aspect of the invention a converse arrangement is
used, wherein the springs are carried on at least one of the posts
instead of within a receptacle. However, the centering action is
the same.
[0009] Thus the invention also provides a subsea structure
comprising a plurality of substantially parallel guide posts
wherein, for the reception of a second structure which comprises a
support and depending therefrom a plurality of tubular receptacles
each positioned for fitment on a respective one of the guide posts,
at least one of the posts carries a plurality of longitudinally
disposed semi-elliptical springs disposed to engage the interior of
the respective receptacle and thereby to axially centre the
receptacle with respect to the guide post.
[0010] According to this aspect of the invention a subsea assembly
comprises a first structure comprising a plurality of substantially
parallel guide posts; and a second structure comprising a support
and depending therefrom a plurality of tubular receptacles each
positioned for fitment on a respective one of the guide posts;
wherein at least one of the posts carries a plurality of
longitudinally disposed semi-elliptical springs disposed to engage
the interior of the respective receptacle and thereby to axially
centre the receptacle with respect to the guide post.
[0011] Each spring may be secured to a respective post at one end
and be adjustably supported with respect to the post at its other
end. The said other end of the spring may be supported relative to
the respective post by a member which is captive within the
respective spring. Each spring may have at each end an axially
extending foot.
[0012] As before there may be four springs disposed at 90.degree.
degree intervals about the axis of a post, so as to provide a
centering action for orthogonal directions laterally of the
respective post. In a specific example all the posts may have
springs as aforesaid.
[0013] The first structure may comprise a central post around which
the said guide posts are disposed and the second structure may
comprise a cooperative part disposed for fitment over the central
post.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] FIG. 1 is a plan view of one structure according to a
preferred embodiment of the invention;
[0015] FIG. 2 is a sectional view of two structures according to a
preferred embodiment of the invention;
[0016] FIG. 3 is a sectional view of two structures according to
one embodiment of the invention;
[0017] FIG. 4 is a detail of the embodiment shown in FIG. 3;
[0018] FIG. 5 is a view showing structures which are misaligned but
otherwise similar to FIG. 3, which shows structures which are
aligned;
[0019] FIG. 6 is a detail on the arrow A in FIG. 5;
[0020] FIG. 7 is a sectional view of two structures according to
another embodiment of the invention;
[0021] FIG. 8 is a detail of the embodiment shown in FIG. 7;
[0022] FIG. 9 is a view showing structures which are misaligned but
otherwise similar to FIG. 7, which shows structures which are
aligned; and
[0023] FIG. 10 is a detail on the arrow A in FIG. 9.
DESCRIPTION OF PREFERRED EMBODIMENTS
[0024] FIGS. 1 and 2 illustrate two structures 1 and 2 which embody
one example of the invention. In this example the structure 1 is
intended to be a lower of the two structures and the structure 2 is
intended to be lowered onto the first structure 1 in order to make
some operative connection when the structures are fully engaged.
However, the assembly may be inverted. Moreover, the direction of
engagement may be oblique or at right angles to the vertical.
[0025] In the present example the structure 1 comprises a casing 3
for a subsea installation that may be part of a module, manifold,
well or other equipment. In this example two or more substantially
parallel guide posts 4 extend upwardly from the structure 1.
Typically there may be four such posts, to provide ultimately
stability of the structure 2 about two horizontal axes but the
actual number depends on design choice. Only two of the four posts
are shown in FIG. 2.
[0026] The structure 1 includes at its upper side a post 5 which
supports a peripheral platform 6. This platform is a datum for the
central part of the structure 2. A top part 7 of the post 5 extends
above the platform. It may be hollow so as to allow (for example)
fluid flow. In this example the post is disposed centrally between
the guide posts 4.
[0027] The structure 2 comprises a central portion 8 which
comprises a part 9 for cooperation with the post 5. The part 9 is
in this example an inverted bucket which can fit over the post 5.
An upper part of the central portion of the structure 2 is a marine
riser 10 which is in communication with the interior of the bucket
9.
[0028] Extending laterally from the central portion of the
structure 2 are lateral arms 11 each of which supports a tubular
receptacle 12 each of which corresponds to one of the guide posts
and is positioned to receive the respective guide posts as the
structure 2 is lowered towards the structure 1. The receptacles are
all similar and only the left-hand receptacle 12a in FIGS. 1 and 2
will be described mainly with reference to FIG. 4, which
illustrates to a larger scale the detail within the circle X in
FIG. 3.
[0029] The receptacle 12a has a straight tubular portion 13 of
constant cross section and an outwardly flared lower rim 14. This
constitutes a docking cone which facilitates initial engagement of
the receptacle and post when as usual they are not initially
axially aligned. Within the portion 13 are disposed semi-elliptical
springs 15. There may be two opposed springs but preferably as
shown there are four springs in two orthogonal pairs. Each spring
is disposed lengthwise in the portion 13. It is fixed to the
portion at its upper end at or near the upper rim of the portion
13. At its other end the spring is supported by a member 18 which
extends through a respective hole 17 in the portion 13. The member
is captive within the hole (which may be threaded) but allows
movement of the lower end of the spring 15 relative to the tubular
portion 13. The member 18 may be a bolt extending through the
portion 13 to contact the foot of the spring 15. It may be adjusted
lengthwise to set an adjustable radial limit for the spring and can
be locked in position by a securing nut 16. Each spring has a small
axially extending foot at each end. The foot 19 at the upper end
allows securing of the upper end by welding whereas the foot 20 at
the lower end enables sliding movement of the lower end with
respect to the member 18.
[0030] The springs in each receptacle engage slidingly the outer
surface of the guide post 4 and provide an automatic centering
action. For this purpose the springs should be substantially
similar in shape and spring rate. In this example the centering
action is along two axes normal to the axis of the post 4.
[0031] FIGS. 3 and 4 illustrate the structures 1 and 2 when they
have been mutually engaged correctly.
[0032] FIG. 5 illustrates the structure 1 and 2 when as will
frequently occur there is obliquity in the approach of the
structures as indicated by the curved arrow B. FIG. 6 is a plan
view on arrow A of the receptacle 12a and its post in this
condition. The obliquity can be accommodated by the springs and
corrected to leave the structures in the positions shown in FIG.
3.
[0033] A second embodiment of the invention is illustrated in FIGS.
7 to 10. As is shown in FIG. 7 the structure 1 as before comprises
a casing 3 for a subsea installation that may be part of a module,
manifold, well or other equipment. In this example two or more
substantially parallel guide posts 4 extend upwardly from the
structure 1. Typically there may be four such posts, to provide
ultimately stability of the structure 2 about two horizontal axes
but the actual number depends on design choice. Only two of the
four posts are shown in FIG. 2.
[0034] The structure 1 includes at its upper side a post 5 which
supports a peripheral platform 6. This platform is a datum for the
central part of the structure 2. A top part 7 of the post 5 extends
above the platform. It may be hollow so as to allow (for example)
fluid flow. In this example the post is disposed centrally between
the guide posts 4.
[0035] The structure 2 comprises a central portion 8 which
comprises a part 9 for cooperation with the post 5. The part 9 is
in this example an inverted bucket which can fit over the post 5.
An upper part of the central portion of the structure 2 is a marine
riser 10 which is in communication with the interior of the bucket
9.
[0036] Extending laterally from the central portion of the
structure 2 are lateral arms 11 each of which supports a tubular
receptacle 12 each of which corresponds to one of the guide posts
and is positioned to receive the respective guide posts as the
structure 2 is lowered towards the structure 1. The receptacles are
all similar and only the left-hand receptacle 12a in FIG. 7 will be
described mainly with reference to FIG. 8, which illustrates to a
larger scale the detail within the circle Y in FIG. 7.
[0037] The receptacle 12a has a straight tubular portion 13 of
constant cross section and an outwardly flared lower rim 14 (FIG.
10). This receptacle constitutes a docking cone which facilitates
initial engagement of the receptacle and post when as usual they
are not initially axially aligned. On the post 4 are disposed
semi-elliptical springs 15. There may be two opposed springs but
preferably as shown there are four springs in two orthogonal pairs.
Each spring is disposed lengthwise relative to the post and the
receptacle 13. It is fixed to the post 4 near the top thereof by a
foot 19 at its upper end. At its other end 20 the spring has a foot
20 which is supported by a screw 21 which extends through a
respective hole in the end 20. The screw is adjustable to move the
foot 20 radially with respect to the post and may be secures by a
nut 22. The screw allows movement of the lower end of the spring 15
relative to the tubular portion 13.
[0038] The springs on each post engage slidingly the inner surface
of the tubular part 13 of the respective receptacle 12 and provide
an automatic centering action. For this purpose the springs should
be substantially similar in shape and spring rate. In this example
the centering action is along two axes normal to the axis of the
post 4.
[0039] FIGS. 7 and 8 illustrate the structures 1 and 2 when they
have been mutually engaged correctly.
[0040] FIG. 9 illustrates the structures when as will frequently
occur there is obliquity in the approach of the structures as
indicated by the curved arrow B. FIG. 10 is a plan view on arrow A
of the receptacle 12a and its post in this condition. The obliquity
can be accommodated by the springs and corrected to leave the
structures in the positions shown in FIG. 7.
* * * * *