Note: Descriptions are shown in the official language in which they were submitted.
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1 Expanding and Collapsing Apparatus and Methods of Use
2
3 The present invention relates to an expanding and collapsing apparatus
and methods of
4 use, and in particular aspects, to an expanding apparatus in the form of
a ring, operable to
move between a collapsed condition and an expanded condition. The invention
also
6 relates to tools and devices incorporating the expansion apparatus and
methods of use.
7 Preferred embodiments of the invention relate to oilfield apparatus
(including but not
8 limited to downhole apparatus and wellhead apparatus) incorporating the
apparatus and
9 methods of use.
11 Background to the invention
12
13 In many fields of mechanical engineering, and in the field of
hydrocarbon exploration and
14 production in particular, it is known to provide expansion mechanisms
for the physical
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1 interaction of tubular components. Expansion mechanisms may expand
outwardly to
2 engage an external surface, or may collapse inwardly to engage an
internal surface.
3
4 Applications are many and varied, but those in hydrocarbon exploration
and production
include the actuation and setting of flow barriers and seal elements such as
plugs and
6 packers, anchoring and positioning tools such as wellbore anchors, casing
and liner
7 hangers, and locking mechanisms for setting equipment downhole. Other
applications
8 include providing mechanical support or back up for elements such as
elastomers or
9 inflatable bladders.
11 A typical anti-extrusion ring is positioned between a packer or seal
element and its
12 actuating slip members, and is formed from a split or segmented metallic
ring. During
13 deployment of the packer or seal element, the segments move to a
radially expanded
14 condition. During expansion and at the radially expanded condition,
spaces are formed
between the segments, as they are required to occupy a larger annular volume.
These
16 spaces create extrusion gaps, which may result in failure of the packer
or seal under
17 working conditions.
18
19 Various configurations have been proposed to minimise the effect of
spaces between anti-
extrusion segments, including providing multi-layered rings, such that
extrusion gaps are
21 blocked by an offset arrangement of segments. For example, US 6,598,672
describes an
22 anti-extrusion rings for a packer assembly which has first and second
ring portions which
23 are circumferentially offset to create gaps in circumferentially offset
locations.
24
US 2,701,615 discloses a well packer comprising an arrangement of crowned
spring metal
26 elements which are expanded by relative movement.
27
28 Other proposals, for example those disclosed in US 3,572,627, US
7,921,921,
29 US 2013/0319654, US 7,290,603 and US 8,167,033 include arrangements of
circumferentially lapped segments. US 3,915,424 describes a similar
arrangement in a
31 drilling BOP configuration, in which overlapping anti-extrusion members
are actuated by a
32 radial force to move radially and circumferentially to a collapsed
position which supports
33 annular sealing elements. Such arrangements avoid introducing extrusion
gaps during
34 expansion, but create a ring with uneven or stepped faces or flanks.
These configurations
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1 do not provide an unbroken support wall for a sealing element, are
spatially inefficient, and
2 may be difficult to reliably move back to their collapsed configurations.
3
4 US 8,083,001 proposes an alternative configuration in which two sets of
wedge shaped
segments are brought together by sliding axially with respect to one another
to create an
6 expanded gauge ring.
7
8 In anchoring, positioning, setting, locking and connection applications,
radially expanding
9 and collapsing structures are typically circumferentially distributed at
discrete locations
when at their increased outer diameter. This reduces the surface area
available to contact
11 an auxiliary engagement surface, and therefore limits the maximum force
and pressure
12 rating for a given size of device.
13
14 Summary of the invention
16 It is amongst the claims and objects of the invention to provide an
expanding and
17 collapsing apparatus and methods of use which obviate or mitigate
disadvantages of
18 previously proposed expanding and collapsing apparatus.
19
It is amongst the aims and objects of the invention to provide an oilfield
apparatus,
21 including a downhole apparatus or a wellhead apparatus, incorporating an
expanding and
22 collapsing apparatus, which obviates or mitigates disadvantages of prior
art oilfield
23 apparatus.
24
Further aims and objects of the invention will be apparent from reading the
following
26 description.
27
28 According to a first aspect of the invention, there is provided an
expanding and collapsing
29 ring apparatus comprising:
a plurality of elements assembled together to form a ring structure oriented
in a plane
31 around a longitudinal axis;
32 wherein the ring structure is operable to be moved between a collapsed
condition and a
33 first expanded condition by movement of the plurality of elements on
actuation by an axial
34 force;
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1 and wherein the apparatus further comprises a secondary expanding and
collapsing
2 mechanism operable to move the first ring structure between its collapsed
condition or its
3 first expanded condition to a second expanded condition on actuation by
an axial force.
4
The ring structure may be a first ring structure, and the apparatus may
comprise at least
6 one additional ring structure, wherein the additional ring structure is
operable to move the
7 first ring structure from an intermediate expanded condition to a fully
expanded condition.
8
9 Preferably, the plurality of elements is operable to be moved relative to
one another
between the expanded and collapsed conditions, and more preferably, is
operable to be
11 moved by sliding the elements with respect to one another in the plane
of the ring
12 structure.
13
14 The plane of the ring structure may be perpendicular to the longitudinal
axis. The ring
structure, and its plane of orientation, may be operable to move on the
apparatus during
16 expansion and/or collapsing. The movement of the plane may be an axial
sliding
17 movement, during expanding and/or collapsing of the ring structure.
18
19 The apparatus may be normally collapsed, and may be actuated to be
expanded.
Alternatively, the apparatus may be normally expanded, and may be actuated to
be
21 collapsed.
22
23 The ring structure may comprise one or more ring surfaces, which may be
presented to an
24 auxiliary surface, for example the surface of a tubular, when actuated
to an expanded
condition or a collapsed condition. The one or more ring surfaces may include
a ring
26 surface which is parallel to the longitudinal axis of the apparatus.
Alternatively, or in
27 addition, the one or more ring surfaces may include a surface which is
perpendicular to the
28 longitudinal axis of the apparatus, and/or a surface which is inclined
to the longitudinal axis
29 of the apparatus.
31 The ring surface may be an outer ring surface, and may be a
substantially cylindrical
32 surface. The ring surface may be arranged to contact or otherwise
interact with an inner
33 surface of a tubular or bore.
34
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1 The ring surface may be substantially smooth. Alternatively, the ring
surface may be
2 profiled, and/or may provided with one or more functional formations
thereon, for
3 interacting with an auxiliary surface.
4
5 In the collapsed condition, the elements may be arranged generally at
collapsed radial
6 positions, and may define a collapsed outer diameter and inner diameter
of the ring
7 structure.
8
9 In the first expanded condition, the elements may be arranged generally
at expanded
radial positions, and may define a first expanded outer diameter and inner
diameter of the
11 ring structure. The ring surface may be located at or on the expanded
outer diameter of
12 the ring structure, or may be located at or on the collapsed inner
diameter of the ring
13 structure.
14
The elements may be configured to move between their first expanded and
collapsed
16 radial positions in a path which is tangential to a circle described
around and concentric
17 with the longitudinal axis.
18
19 Preferably, each element of the ring structure comprises a first contact
surface and second
contact surface respectively in abutment with first and second adjacent
elements. The
21 elements may be configured to slide relative to one another along their
respective contact
22 surfaces.
23
24 The first contact surface and/or the second contact surface may be
oriented tangentially to
a circle described around and concentric with the longitudinal axis. The first
contact
26 surface and the second contact surface are preferably non-parallel. The
first contact
27 surface and the second contact surface may converge towards one another
in a direction
28 towards an inner surface of the ring structure (and may therefore
diverge away from one
29 another in a direction away from an inner surface of the ring
structure).
31 At least some of the elements are preferably provided with interlocking
profiles for
32 interlocking with an adjacent element. Preferably the interlocking
profiles are formed in the
33 first and/or second contact surfaces. Preferably, an element is
configured to interlock with
34 a contact surface of an adjacent element. Such interlocking may prevent
or restrict
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1 separation of assembled adjacent elements in a circumferential and/or
radial direction of
2 the ring structure, while enabling relative sliding movement of adjacent
elements.
3
4 Preferably, at least some of, and more preferably all of, the elements
assembled to form a
ring are identical to one another, and each comprises an interlocking profile
which is
6 configured to interlock with a corresponding interlocking profile on
another element. The
7 interlocking profiles may comprise at least one recess such as groove,
and at least one
8 protrusion, such as a tongue or a pin, configured to be received in the
groove. The
9 interlocking profiles may comprise at least one dovetail recess and
dovetail protrusion.
11 The first and second contact surfaces of an element may be oriented on
first and second
12 planes, which may intersect an inner surface of the ring at first and
second intersection
13 lines, such that a sector of an imaginary cylinder is defined between
the longitudinal axis
14 and the intersection lines. The central angle of the sector may be 45
degrees or less.
Such a configuration corresponds to eight or more elements assembled together
to form
16 the ring structure.
17
18 Preferably, the central angle of the sector is 30 degrees or less,
corresponding to twelve or
19 more elements assembled together to form the ring. More preferably, the
central angle of
the sector is in the range of 10 degrees to 20 degrees, corresponding to
eighteen to thirty-
21 six elements assembled together to form the ring. In a particular
preferred embodiment,
22 the central angle of the sector is 15 degrees, corresponding to twenty-
four elements
23 assembled together to form the ring structure.
24
Preferably, an angle described between the first contact and second contact
surfaces
26 corresponds to the central angle of the sector. Preferably therefore, an
angle described
27 between the first contact and second contact surfaces is in the range of
10 degrees to 20
28 .. degrees, and in a particular preferred embodiment, the angle described
between the first
29 contact and second contact surfaces is 15 degrees, corresponding to
twenty-four elements
assembled together to form the ring structure.
31
32 In a preferred embodiment, the apparatus comprises a support surface for
the ring
33 structure. The support surface may be the outer surface of a mandrel or
tubular. The
34 support surface may support the ring structure in a collapsed condition
of the apparatus.
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1 In some embodiments, the apparatus is operated in its second expanded
condition, and in
2 other embodiments, the apparatus is operated in its collapsed condition.
Preferably,
3 elements forming the ring structure are mutually supportive in an
operating condition of the
4 apparatus. Where the operating condition of the apparatus its expanded
condition (i.e.
when the apparatus is operated in its expanded condition), the ring structure
is preferably
6 a substantially solid ring structure in its second expanded condition,
and the elements may
7 be fully mutually supported.
8
9 The apparatus may comprise a formation configured to impart a radial
expanding or
collapsing force component to the elements of a ring structure and/or
secondary
11 expanding and collapsing mechanism from an axial actuation force. The
apparatus may
12 comprise a pair of formations configured to impart a radial expanding or
collapsing force
13 component to the elements of a ring structure from an axial actuation
force. The formation
14 (or formations) may comprise a wedge or wedge profile, and may comprise
a cone wedge
or wedge profile.
16
17 The apparatus may comprise a biasing means, which may be configured to
bias the first
18 ring structure to one of its expanded or collapsed conditions. The
biasing means may
19 comprise a circumferential spring, a garter spring, or a spiral
retaining ring. The biasing
means may be arranged around an outer surface of a ring structure, to bias it
towards a
21 collapsed condition, or may be arranged around an inner surface of a
ring structure, to
22 bias it towards an expanded condition. One or more elements may comprise
a formation
23 such as a groove for receiving the biasing means. Preferably, grooves in
the elements
24 combine to form a circumferential groove in the ring structure. Multiple
biasing means may
be provided on the ring structure.
26
27 Preferably, the secondary expanding and collapsing mechanism comprises a
second ring
28 structure, and more preferably comprises a pair of second ring
structures. The second
29 ring structure(s) may be operable to move the first ring structure from
an intermediate
expanded condition to a fully expanded condition. The pair of second ring
structures may
31 be disposed on opposing sides of the first ring structure. The second
ring structure(s) may
32 comprise a plurality of second elements assembled together to form the
second ring
33 structure oriented in a plane around the longitudinal axis.
34
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1 The plurality of second elements may be operable to be moved relative to
one another
2 between an expanded and collapsed conditions of the respective second
ring structure,
3 and more preferably, is operable to be moved by sliding the second
elements with respect
4 to one another in the plane of the second ring structure.
6 The second ring structures may define an outer surface, which may be
inclined with
7 respect to a surface parallel to the longitudinal axis. The outer
surfaces may be conical
8 wedge surfaces, which may face the first ring structure.
9
The apparatus may comprise at least one pair of additional ring structures,
wherein the
11 pair of additional ring structures are operable to move the first ring
structure from an
12 intermediate expanded condition to a fully expanded condition. The pair
of additional ring
13 structures may be disposed (axially) on either side of the first ring
structure, and may act
14 together to move the ring structure from an intermediate expanded
condition to a fully
expanded condition.
16
17 The plurality of elements of the additional ring structure may be
operable to be moved
18 between the expanded and collapsed conditions by sliding with respect to
one another in
19 the plane of the additional ring structure, in a direction tangential to
a circle concentric with
the additional ring structure. In other respects, the additional ring
structure and its
21 elements may have features in common with the ring structure described
herein.
22
23 The additional ring structure, and/or its elements, may be operable to
transfer an axial
24 actuation force to the elements of the first ring structure. The
additional ring structure,
and/or its elements may comprise one or more wedge profiles, which may be
conical
26 wedge profiles. The one or more wedge profiles may be defined by an
outer surface of the
27 elements of the additional ring structure.
28
29 The apparatus may comprise a plurality of additional ring structures,
which may be
arranged in functional pairs, and/or which may be operable to move the first
ring structure
31 from an intermediate expanded condition to a subsequent intermediate
expanded
32 condition, or a fully expanded condition.
33
34 Preferably, each additional ring structure comprises a biasing means,
which may be
configured to bias the first ring structure to one of its expanded or
collapsed conditions.
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1 The biasing means may comprise a circumferential spring, a garter spring,
or a spiral
2 retaining ring. Preferably, the biasing means of the first and additional
ring structures are
3 selected to define a sequence of expanding and collapsing of the
apparatus. Preferably,
4 the biasing means of the first and additional ring structures are
selected to expand the
centremost ring structure before an adjacent pair of additional ring
structures. The biasing
6 means additional ring structures may be selected to expand a first pair
of additional ring
7 structures before an adjacent pair of additional ring structures located
axially outside of the
8 first pair or additional ring structures.
9
The biasing means may be disposed on an outer surface of a ring structure, or
may be
11 disposed in a groove on the outer surface of a ring structure.
12
13 Alternatively, or in addition, a biasing means may be disposed in
apertures in the
14 elements. The biasing means may be threaded through each element, and
may then be
joined to make a continuous loop upon assembly. The biasing means may be
disposed in-
16 board of the external surface of the elements. The biasing means may be
located directly
17 over an interlocking feature such as a dovetail, and/or may be located
centrally on the ring
18 structure.
19
Preferably, a functional pair of additional ring structures and/or the
elements thereof is
21 symmetrical about a centre ring structure. Each of a functional pair of
additional ring
22 structures and/or the elements thereof may be configured to move axially
with respect to
23 one another on the apparatus, and may be configured to move into
abutment with one
24 another. Preferably, each of a functional pair of additional ring
structures and/or the
elements thereof are configured to limit the travel of a corresponding
additional ring
26 structures and/or the elements thereof.
27
28 External profiles of the elements may comprise chamfers, which may at
least partially
29 define a surface of one or more flanks of an assembled ring structure.
31 An assembled ring structure may comprise at least one flank having an at
least partially
32 smoothed conical surface. In use, the at least partially smoothed
conical surface may
33 facilitate deployment of the apparatus, for example by improving the
sliding action of an
34 adjacent ring on the flank during expansion. The flank may be a flank of
a supporting ring
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1 structure. The at least one flank may be an inward facing flank, or a
flank facing a central
2 ring structure or a ring structure disposed between the flank and a
central ring structure.
3
4 Alternatively, or in addition, the elements may be profiled such that the
ring structures
5 define at least partially smooth conical surfaces on their outward facing
flanks when in
6 their expanded condition. The at least partially smooth conical surfaces
may combine in
7 the assembled, expanded apparatus, to provide a substantially or fully
smooth surface of
8 flank of the expanded apparatus, which may be suitable for abutment with
and/or support
9 of an adjacent element such as an elastomer.
11 The surfaces of the plurality of elements may be configured to be
presented directly
12 against a surface with which it interacts, such as a borehole wall.
Alternatively, or in
13 addition, the apparatus may comprise an intermediate structure or
material disposed
14 between the surfaces of the elements and a surface with which it
interacts.
16 In one embodiment, the elements of the ring structure are configured to
conform, deform
17 or compress in a collapsed condition to form a fluid barrier or seal
with an object in the
18 throughbore. The elements may be formed, at least partially, from a
compressible and/or
19 resilient material, such as an elastomer, rubber or polymer.
21 Alternatively, or in addition, the elements may be formed, at least
partially, from a metal or
22 metal alloy, and may be coated or covered with a compressible and/or
resilient material,
23 such as an elastomer, rubber or polymer.
24
According to a second aspect of the invention, there is provided an expanding
and
26 collapsing ring apparatus comprising:
27 a plurality of elements assembled together to form a first ring
structure oriented in a plane
28 around a longitudinal axis;
29 wherein the first ring structure is operable to be moved between a
collapsed condition and
a first expanded condition by movement of the plurality of elements on
actuation by an
31 axial force;
32 and wherein the apparatus further comprises at least one pair of
additional ring structures,
33 wherein the pair of additional ring structures are operable to move the
first ring structure
34 from an intermediate expanded condition to a fully expanded condition.
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1 The additional ring structure may comprise a plurality of elements
assembled together to
2 form a ring structure, and may be oriented in a plane around a
longitudinal axis. The
3 additional ring structure may be operable to be moved between an expanded
condition
4 and a collapsed condition by movement of the plurality of elements on
actuation by an
axial force. The plurality of elements of the additional ring structure may be
operable to be
6 moved between the expanded and collapsed conditions by sliding with
respect to one
7 another in the plane of the additional ring structure, in a direction
tangential to a circle
8 concentric with the additional ring structure. In other respects, the
additional ring structure
9 and its elements may have features in common with the ring structure
described herein.
11 Embodiments of the second aspect of the invention may include one or
more features of
12 the first aspect of the invention or its embodiments, or vice versa.
13
14 According to a third aspect of the invention, there is provided an
oilfield tool comprising the
apparatus of any of the first or second aspects of the invention.
16
17 The oilfield tool may be a downhole tool. Alternatively, the oilfield
tool may comprise a
18 wellhead tool.
19
The downhole tool may comprise a downhole tool selected from the group
consisting of a
21 plug, a packer, an anchor, a tubing hanger, or a downhole locking tool.
22
23 The plug may be a bridge plug, and may be a retrievable bridge plug.
Alternatively, the
24 plug may be a permanent plug.
26 Embodiments of the third aspect of the invention may include one or more
features of the
27 first or second aspects of the invention or their embodiments, or vice
versa.
28
29 According to a fourth aspect of the invention, there is provided
variable diameter downhole
tool, the tool comprising an apparatus according to a previous aspect of the
invention.
31
32 The downhole tool may be selected from the group consisting of a
wellbore centraliser, a
33 wellbore broach tool, and a wellbore drift tool.
34
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1 Embodiments of the fourth aspect of the invention may include one or more
features of the
2 first or second aspects of the invention or their embodiments, or vice
versa.
3
4 According to a fifth of the invention, there is provided a connector
system comprising a first
connector and a second connector, wherein one of the first and second
connectors
6 comprises the apparatus of any of the first or second aspects of the
invention.
7
8 Embodiments of the fifth aspect of the invention may include one or more
features of the
9 first or second aspects of the invention or their embodiments, or vice
versa.
11 According to a sixth aspect of the invention, there is provided patch
apparatus for a fluid
12 conduit or tubular, the patch apparatus comprising the apparatus of any
of the first or
13 second aspects of the invention.
14
Embodiments of the sixth aspect of the invention may include one or more
features of the
16 first or second aspects of the invention or their embodiments, or vice
versa.
17
18 According to a seventh aspect of the invention, there is provided a
method of expanding
19 an apparatus, the method comprising:
providing an apparatus comprising: a plurality of elements assembled together
to form a
21 ring structure oriented in a plane around a longitudinal axis; and a
secondary expanding
22 and collapsing mechanism;
23 imparting an axial force to the ring structure to move the plurality of
elements from a
24 collapsed condition to a first expanded condition; and
imparting an axial force to the secondary expanding and collapsing mechanism
to move
26 the first ring structure from its first expanded condition to a second
expanded condition.
27
28 Embodiments of the seventh aspect of the invention may include one or
more features of
29 the first or second aspects of the invention or their embodiments, or
vice versa.
31 According to an eighth aspect of the invention, there is provided a
method of collapsing an
32 apparatus, the method comprising:
33 providing an apparatus comprising: a plurality of elements assembled
together to form a
34 ring structure oriented in a plane around a longitudinal axis; and a
secondary expanding
and collapsing mechanism;
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1 imparting an axial force to the ring structure to move the plurality of
elements from a
2 collapsed condition to a first expanded condition; and
3 releasing or reducing an axial force from the secondary expanding and
collapsing
4 mechanism to move the first ring structure from a second expanded
condition to a first
expanded condition; and
6 releasing or reducing an axial force from the ring structure to move the
plurality of
7 elements, thereby moving the ring structure from the first expanded
condition to a
8 collapsed condition.
9
Embodiments of the eighth aspect of the invention may include one or more
features of the
11 first or second aspects of the invention or their embodiments, or vice
versa.
12
13 According to a further aspect of the invention, there is provided an
expanding and
14 collapsing ring apparatus comprising:
a plurality of elements assembled together to form a ring structure oriented
in a plane
16 around a longitudinal axis;
17 wherein the ring structure is operable to be moved between a collapsed
condition and a
18 first expanded condition by movement of the plurality of elements;
19 and wherein the apparatus further comprises a secondary expanding and
collapsing
mechanism operable to move the first ring structure between its collapsed
condition or its
21 first expanded condition to a second expanded condition.
22
23 According to a further aspect of the invention, there is provided an
expanding and
24 collapsing ring apparatus comprising:
a plurality of elements assembled together to form a first ring structure
oriented in a plane
26 around a longitudinal axis;
27 wherein the first ring structure is operable to be moved between a
collapsed condition and
28 a first expanded condition by movement of the plurality of elements;
29 and wherein the apparatus further comprises at least one pair of
additional ring structures,
wherein the pair of additional ring structures are operable to move the first
ring structure
31 from an intermediate expanded condition to a fully expanded condition.
32
33 According to a further aspect of the invention, there is provided a
method of expanding an
34 apparatus, the method comprising:
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1 providing an apparatus comprising: a plurality of elements assembled
together to form a
2 ring structure oriented in a plane around a longitudinal axis; and a
secondary expanding
3 and collapsing mechanism;
4 imparting a force to the ring structure to move the plurality of elements
from a collapsed
condition to a first expanded condition; and
6 imparting a force to the secondary expanding and collapsing mechanism to
move the first
7 ring structure from its first expanded condition to a second expanded
condition.
8
9 According to a further aspect of the invention, there is provided a
method of collapsing an
apparatus, the method comprising:
11 providing an apparatus comprising: a plurality of elements assembled
together to form a
12 ring structure oriented in a plane around a longitudinal axis; and a
secondary expanding
13 and collapsing mechanism;
14 imparting a force to the ring structure to move the plurality of
elements from a collapsed
condition to a first expanded condition; and
16 releasing or reducing a force from the secondary expanding and
collapsing mechanism to
17 move the first ring structure from a second expanded condition to a
first expanded
18 condition; and
19 releasing or reducing a force from the ring structure to move the
plurality of elements,
thereby moving the ring structure from the first expanded condition to a
collapsed
21 condition.
22
23 According to a further aspect of the invention, there is provided fluid
conduit tool
24 comprising the apparatus according to any previous aspect of the
invention. The fluid
conduit tool may be configured for use in pipelines or other fluid conduits,
which may be
26 surface fluid conduits or subsea fluid conduits, and may be oilfield or
non-oilfield fluid
27 conduits.
28
29 Embodiments of the further aspects of the invention may include one or
more features of
the first or second aspects of the invention or their embodiments, or vice
versa.
31
32 Brief description of the drawings
33
34 There will now be described, by way of example only, various embodiments
of the
invention with reference to the drawings, of which:
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1
2 Figures 1A to Figure 1D are respectively perspective, first end, part
sectional and second
3 end views of an apparatus useful for understanding the invention, shown
in a collapsed
4 condition;
5
6 Figures 2A to 2D are respectively perspective, first side, part sectional
and second side
7 views of the apparatus of Figures 1A to 1D, shown in an expanded
condition;
8
9 Figures 3A and 3B are geometric representations of an element of the
apparatus of
10 Figures 1A and 1D, shown from one side;
11
12 Figures 4A to Figure 4F are respectively first perspective, second
perspective, plan, first
13 end, lower, and second end views of an element of the apparatus of
Figures 1A to 1D;
14
15 Figures 5A to 5C are respectively perspective, sectional and end views
of an apparatus
16 according to an embodiment of the invention, shown in a collapsed
condition;
17
18 Figures 6A to 60 are respectively perspective, sectional and end views
of the apparatus of
19 Figures 5A to 5C, shown in an expanded condition;
21 Figure 7 is a geometric representation of a centre element of the
apparatus of Figures 5A
22 to 5C, shown from one side;
23
24 Figures 8A to 8F are respectively first perspective, second perspective,
plan, first end,
lower, and second end views of a centre element of the apparatus of Figures 5A
to 5C;
26
27 Figure 9 is a geometric representation of an outer element of the
apparatus of Figures 5A
28 to 5C, shown from one side;
29
Figure 10A to 10H are respectively first perspective, second perspective,
third perspective,
31 fourth perspective, plan, first end, lower, and second end views of an
outer element of the
32 apparatus of Figures 5A to 5C;
33
34 Figures 11A to 11C are respectively perspective, sectional and end views
of an apparatus
according to an alternative embodiment of the invention, shown in a collapsed
condition;
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1
2 Figures 12A to 120 are respectively perspective, sectional and end views
of the apparatus
3 of Figures 11A to 110, shown in an expanded condition;
4
Figures 13A and 13B are respectively perspective and sectional views of an
apparatus
6 according to an alternative embodiment of the invention, shown in a
collapsed condition;
7
8 Figures 14A to 14D are respectively perspective, first sectional, end,
and second sectional
9 views of the apparatus of Figures 13A and 13B, shown in an expanded
condition;
11 Figure 15 is a geometric representation of a centre element of the
apparatus of Figures
12 13A and 13B, shown from one side;
13
14 Figures 16A to 16F are respectively first to fourth perspective, first
end, and second end
views of a centre element of the apparatus of Figures 13A and 13B;
16
17 Figures 17A and 17B are respectively perspective and sectional views of
a patch
18 apparatus according to an embodiment of the invention, shown in a
collapsed condition;
19
Figures 18A and 18B are respectively perspective and sectional views of the
apparatus of
21 Figures 17A and 17B, shown in an expanded condition;
22
23 Figure 19 is a side view of an apparatus according to an alternative
embodiment of the
24 invention in a first, collapsed condition;
26 Figure 20 is a side view of the apparatus of Figure 19 a second,
collapsed condition;
27
28 Figures 21A and 21B are respectively plan and isometric views of an
element of the
29 apparatus of Figures 19 and 20; and
31 Figures 22A and 22B are respectively plan and isometric views of a
second element of the
32 apparatus of Figures 19 and 20.
33
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17
1 Detailed description of preferred embodiments
2
3 Referring firstly to Figures 1A to 4F, the principles of the invention
will be described with
4 reference to an expanding apparatus which is useful for understanding the
invention and
its embodiments. In the arrangement of Figures 1A to 4F, the expanding
apparatus,
6 generally depicted at 10, comprises an expanding ring structure
configured to be
7 expanded from a first collapsed or unexpanded condition (shown in Figures
1A to 1D) and
8 a second expanded condition (shown in Figures 2A to 2D). The apparatus of
this and
9 other embodiments may be referred to as "expanding apparatus" for
convenience, as they
are operable to move to an expanded state from a normal collapsed state.
However, the
11 apparatus may equally be referred to as a collapsing apparatus, or an
expanding or
12 collapsing apparatus, as they are capable of being expanded or collapsed
depending on
13 operational state.
14
The expanding apparatus 10 comprises a plurality of elements 12 assembled
together to
16 form a ring structure 11. The elements 12 define an inner ring surface
which is supported
17 by the outer surface of cylinder 14. Each element comprises an inner
surface 20, an outer
18 surface 21 and first and second contact surfaces 22, 23. The first and
second contact
19 surfaces are oriented in non-parallel planes, which are tangential to a
circle centred on the
longitudinal axis of the apparatus. The planes converge towards the inner
surface of the
21 element. Therefore, each element is in the general form of a wedge, and
the wedges are
22 assembled together in a circumferentially overlapping fashion to form
the ring structure 11.
23 In use, the first and second contact surfaces of adjacent elements are
mutually supportive.
24
As most clearly shown in Figures 3A and 3B, when the ring structure is
expanded to its
26 optimal outer diameter, the orientation planes of the first and second
contact surfaces
27 intersect an inner surface of the ring structure, and together with the
longitudinal axis of
28 the apparatus, the lines of intersection define a sector of a cylinder.
In this case, the ring
29 structure is formed from twenty-four identical elements, and the central
angle 01 is 15
degrees. The angle described between the orientation planes of the first and
second
31 contact surface is the same as the central angle of the cylindrical
sector, so that the
32 elements are arranged rotationally symmetrically in the structure.
33
34 As shown in Figure 3B, each element is based on a notional wedge-shaped
segment of a
ring centred on an axis, with each notional wedge-shaped segment being
inclined with
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18
1 respect to the radial direction of the ring. The nominal outer diameter
of the segment is at
2 the optimum expansion condition of the ring (with radius shown at ri).
3
4 The orientation planes of the first and second contact surfaces of the
element are
tangential to a circle with radius r3concentric with the ring at points ti,
t2. The angle
6 described between the tangent points is equal to the angle 01 of the
segment. The
7 orientation planes of the first and second contact surfaces of each
notional wedge-shaped
8 segment intersect one another on a radial plane P which bisects radial
planes located at
9 the tangent points (i.e. is at an angle of 01/2 to both). This
intersection plane P defines the
expanding and collapsing path of the segment.
11
12 In the configuration shown in Figures 1 and 2, notional wedge-shaped
segments are
13 modified by removal of the tips 29 of the wedges, to provide a curved or
arced inner
14 surface 20 with radius r2 when the ring is in its expanded condition
shown in Figures 2A
and 2D. The modification of the wedge-shaped elements can be thought of as an
increase
16 in diameter of an internal bore through the ring structure by 2(r243),
or a truncation of the
17 inner diameter. This change in the inner diameter from the notional
inner diameter r3 to
18 which the contact surfaces are tangential to a truncated inner diameter
r2, has the effect of
19 changing an angle between the contact surfaces and the radial plane from
the centre of
the ring. Taking angle 02 to be the angle described between the contact
surface and a
21 radial plane defined between the centre point of the ring structure and
the point at which
22 the orientation surface meets or intersects a circle at the radial
position of the inner
23 surface, 02 is changed in dependence on the amount by which the segment
has its inner
24 diameter truncated. For the notional wedge shaped segment, the
orientation planes of the
contact surfaces are tangential to a circle at the inner diameter at r3(i.e.
angle 02 is 90
26 degrees). For the modified elements 12, the orientation planes of the
contact surfaces
27 instead intersect a circle at the (increased) inner diameter at r2 and
are inclined at a
28 reduced angle 02.
29
The angle 02 at which the segment is inclined is related to the amount of
material removed
31 from the notional wedge-shaped segment, but is independent from the
central angle 01 of
32 the wedge. Angle 02 is selected to provide element dimensions suitable
for manufacture,
33 robustness, and fit within the desired annular volume and inner and
outer diameters of the
34 collapsed ring. As the angle 02 approaches 90 degrees, a shallower,
finer wedge profile is
created by the element, which may enable optimisation of the collapsed volume
of the ring
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1 structure. Although a shallower, finer wedge profile may have the effect
of reducing the
2 size of the gaps created at the inner surface of the ring in the
collapsed condition and/or
3 enabling a more compact collapsed condition, there are some consequences.
These
4 include the introduction of flat sections at the inner surfaces of the
elements, which
manifest as spaces at the inner diameter of the ring when in an expanded or
partially
6 expanded condition. When 02 = 90 degrees, all the segments are purely
tangential to
7 inner diameter, the collapsed volume for a given outer diameter and inner
diameter is most
8 efficient, but the inner surface of the ring structure is polygonal with
flat sections created by
9 each segment. In some configurations, these flat sections may be
undesirable. There
may also be potential difficulties with manufacture of the elements and
robustness of the
11 elements and assembled ring structure. However, in many applications,
where the profile
12 of the inner surface of the expanded ring is not critical, for example
when the inner
13 diameter of the ring structure is floating, and/or the true inner
diameter is defined by an
14 actuation wedge profile rather than the inner surface of the ring, this
compromise may not
be detrimental to the operation of the apparatus, and the reduced collapse
volume may
16 justify an inclination angle 02 of (or approaching) 90 degrees.
17
18 In the apparatus of Figures 1 to 4, the angle 02 is 75 degrees. Relaxing
02 to a reduced
19 angle provides a smooth outer diameter and inner diameter profile to the
expanded ring,
as a portion of the inner circular arc is retained at the expense of slightly
increased
21 collapsed volume. It should be noted that the angle 02 is independent
from the angle 81.
22 Where the ring structure is desired to have a circular inner surface,
preferred
23 arrangements may have an angle 02 which is in the range of (90 degrees -
281) to 90
24 degrees inclusive, and particularly preferred arrangements have an angle
02 in the range
of 70 degrees to 90 degrees (most preferably in the range of 73 degrees to 90
degrees).
26 In general, to provide sufficient truncation of the inner diameter to
retain a useful portion of
27 an inner arc and provide a smooth inner surface to the ring structure, a
maximum useful
28 value of 02 is (90 degrees - 81/2). This would be 82.5 degrees in the
described
29 arrangements.
31 In other configurations, also in accordance with embodiments of the
invention (and as will
32 be described below) the geometry of the notional wedge-shaped segments
forming the
33 elements may be unmodified (save for the provision of functional
formations such as for
34 interlocking and/or retention of the elements), without the removal of
material from the tip
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1 of the notional wedge-shaped segments. Such embodiments may be preferred
when
2 there is no requirement for the ring structure to have a circular inner
surface.
3
4 As most clearly shown in Figures 4A to 4F, the first and second contact
surfaces of the
5 element have corresponding interlocking profiles 24 formed therein, such
that adjacent
6 elements can interlock with one another. In this case, the interlocking
profiles comprise a
7 dovetail groove 25 and a corresponding dovetail tongue 26. The
interlocking profiles resist
8 circumferential and/or radial separation of the elements in the ring
structure, but permit
9 relative sliding motion between adjacent elements. The interlocking
profiles also facilitate
10 smooth and uniform expansion and contraction of the elements during use.
It will be
11 appreciated that alternative forms of interlocking profiles, for example
comprising recesses
12 and protrusions of other shapes and forms, may be used within the scope
of the invention.
13
14 The elements are also provided with inclined side wall portions 27,
which facilitate
15 deployment of the apparatus in use. The side wall portions are formed in
an inverted cone
16 shape which corresponds to the shape and curvature of the actuating cone
wedges
17 profiles when the apparatus is in its maximum load condition (typically
at its optimum
18 expansion condition).
19
20 Each element is also provided with a groove 28, and in the assembled
ring structure, the
21 grooves are aligned to provide a circular groove which extends around
the ring. The
22 groove accommodates a biasing element (not shown), for example a spiral
retaining ring
23 of the type marketed by Smalley Steel Ring Company under the Spirolox
brand, or a garter
24 spring. In this case, the biasing means is located around the outer
surface of the
elements, to bias the apparatus towards the collapsed condition shown in
Figures 1A to
26 1D. Although one groove for accommodating a biasing means is provided in
this
27 embodiment, in alternative embodiments of the apparatus, multiple
grooves and biasing
28 means may be provided.
29
The apparatus 10 comprises a wedge member 16, which in this case is an annular
ring
31 having a conical surface 18 opposing one side of the ring structure 11.
The wedge angle
32 corresponds with the angle of the inclined conical side walls 27 of the
elements. A
33 corresponding wedge shaped profile (not shown) is optionally provided on
the opposing
34 side of the ring structure to facilitate expansion of the ring elements.
In alternative
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1 embodiments of the invention this optional additional wedge may be
substituted with an
2 abutment shoulder.
3
4 Operation of the expansion apparatus will now be described. In the first,
collapsed or
unexpanded condition, shown most clearly in Figure 10, the elements are
assembled in a
6 ring structure 11 which extends to a first outer diameter. In this
embodiment, and as
7 shown in Figures 1B and 10, the wedge member 16 defines the maximum outer
diameter
8 of the apparatus in the first condition. The elements are biased towards
the unexpanded
9 condition by a spiral retaining ring (not shown), and are supported on
the inner surface by
the outer surface of the cylinder 14.
11
12 In use, an axial actuation force is imparted on the wedge member 16. Any
of a number of
13 suitable means known in the art can be used for application of the axial
actuation force, for
14 example, the application of a force from an outer sleeve positioned
around the cylinder.
The force causes the wedge member 16 to move axially with respect to the
cylinder, and
16 transfer a component of the axial force onto the recessed side wall of
the elements. The
17 angle of the wedge transfers a radial force component to the elements
12, which causes
18 them to slide with respect to one another along their respective contact
surfaces.
19
The movement of the expanding elements is tangential to a circle defined
around the
21 longitudinal axis of the apparatus. The contact surfaces of the elements
mutually support
22 one another before, during, and after expansion. The radial position of
the elements
23 increases on continued application of the axial actuation force until
the elements are
24 located at a desired outer radial position. This radial position may be
defined by a
controlled and limited axial displacement of the wedge member, or
alternatively can be
26 determined by an inner surface of a bore or tubular in which the
apparatus is disposed.
27
28 Figures 2A to 2D show clearly the apparatus in its expanded condition.
At an optimal
29 expansion condition, shown in Figures 2B and 2D, the outer surfaces of
the individual
elements combine to form a complete circle with no gaps in between the
individual
31 elements. The outer surface of the expansion apparatus can be optimised
for a specific
32 diameter, to form a perfectly round expanded ring (within manufacturing
tolerances) with
33 no extrusion gaps on the inner or outer surfaces of the ring structure.
The design of the
34 expansion apparatus also has the benefit that a degree of under
expansion or over
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1 expansion (for example, to a slightly different radial position) does not
introduce
2 significantly large gaps.
3
4 It is a feature of the invention that the elements are mutually supported
before, throughout,
and after the expansion, and do not create gaps between the individual
elements during
6 expansion or at the fully expanded position. In addition, the arrangement
of elements in a
7 circumferential ring, and their movement in a plane perpendicular to the
longitudinal axis,
8 facilitates the provision of smooth side faces or flanks on the expanded
ring structure.
9 With deployment of the elements in the plane of the ring structure, the
overall width of the
ring structure does not change. This enables use of the apparatus in close
axial proximity
11 to other functional elements.
12
13 The apparatus has a range of applications, some of which are illustrated
in the following
14 example embodiments. However, additional applications of the apparatus
are possible
which exploit its ability to effectively perform one or more of blocking or
sealing an annular
16 path; contacting an auxiliary surface; gripping or anchoring against an
auxiliary surface;
17 locating or engaging with radially spaced profiles; and/or supporting a
radially spaced
18 component.
19
The present invention extends the principles described above to multi-stage or
telescopic
21 expansion apparatus, which have applications to systems in which an
increased
22 expansion ratio is desirable. The following embodiments of the invention
describe
23 examples of such apparatus.
24
Referring now to Figures 5A to 60, there is shown a two-stage expansion
apparatus in
26 accordance with an embodiment of the invention. Figures 5A to 50 are
respectively
27 perspective, longitudinal sectional, and end views of the apparatus in a
first, collapsed
28 condition. Figures 6A to 60 are equivalent views of the apparatus in an
expanded
29 condition. The apparatus, generally depicted at 170, comprises an
expansion assembly
171 formed from three ring structures 172, 173a, 173b, each of which is formed
from
31 separate elements in the manner described with reference to Figures 1 to
4. The ring
32 structures 172, 173a, 173b are disposed on a mandrel 174 between a wedge
portion 175
33 which is fixed on a mandrel, and a moveable cone wedge member 176. An
inner ring
34 structure 172 is formed from a number of individual elements 177
assembled together.
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1 The elements 177 are similar to the elements 12, and their form and
function will
2 understood from Figures 1 to 4 and their accompanying description.
3
4 Figure 7 is a geometric representation of a centre element of the
apparatus of Figures 5A
to 50, shown from one side, and Figures 8A to 8F are respectively first
perspective,
6 second perspective, plan, first end, lower, and second end views of a
centre element 177.
7 The Figures show the inner and outer surfaces, first and second contact
surfaces,
8 interlocking profiles, and grooves for retaining circumferential springs
which are equivalent
9 in form and function to the features of the elements 12. Biasing means in
the form of a
circumferential spring retains the centre ring structure in its collapsed
condition.
11
12 Disposed on either side of the centre ring structure are first and
second outer ring
13 structures 173a, 173b in the form of wedge ring structures. The wedge
ring structures are
14 also assembled from an arrangement of elements which, again, are similar
in form and
function to the elements 12. However, instead of providing an outer surface
which is
16 substantially parallel to the longitudinal axis of the apparatus, the
outer surfaces of the
17 outer elements are inclined to provide respective wedge surfaces 178a,
178b which face
18 the centre ring structure 172.
19
Figure 9 is a geometric representation of an outer element 182 of the
apparatus of Figures
21 5A to 50, shown from one side, and Figures 10A to 10H are respectively
first perspective,
22 second perspective, third perspective, fourth perspective, plan, first
end, lower, and
23 second end views of an outer element 182. The Figures show the inner and
outer
24 surfaces 183, 184, first and second contact surfaces 185, 186,
interlocking profiles 187,
188, and grooves 189 for retaining circumferential springs which are
equivalent in form
26 and function to the features of the elements 12. In the assembled ring
structure, the outer
27 elements and the centre elements are nested with one another, and the
outer surfaces
28 184 of the outer elements define respective wedge profiles for
corresponding centre
29 elements 177 during a first expansion stage as will be described below.
Biasing means in
the form of a circumferential spring retains the outer rings structure in
their collapsed
31 conditions, with the sequencing of the expanding and collapsing movement
controlled by
32 the selection of the relative strengths of the biasing means of the
centre ring and the outer
33 rings.
34
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1 In a first, collapsed condition, the elements of the centre ring
structure and the elements of
2 the first and second outer ring structures, have a maximum outer diameter
which is less
3 than or equal to the outer diameter of the wedge profile 175 and wedge
member 176.
4
Operation of this embodiment of the apparatus will be described, with
additional reference
6 to Figures 6A to 60.
7
8 In common with other embodiments, the apparatus is actuated to be
radially expanded to
9 a second diameter by an axial actuation force which moves the cone wedge
member 176
on the mandrel and relative to the ring structure. The axial actuation force
acts through
11 the ring structures 173a, 173b to impart axial and radial force
components onto the
12 elements. Radial expansion of the ring structures 173a, 173b is resisted
by their
13 respective circumferential springs arranged in grooves 179, and the
forces are transferred
14 to the centre ring structure 172. The elements of the centre ring
experience an axial force
from the wedge surfaces 178a, 178b of the elements of the outer ring
structures, which is
16 translated to a radial expansion force on the elements of the centre
ring structure 172. The
17 radial expansion force overcomes the retaining force of a
circumferential spring in the
18 groove 181 (which is selected to be weaker than the retaining forces of
the circumferential
19 springs in the outer rings), and the elements slide with respect to one
another to expand
the centre ring structure as the outer ring structures move together.
21
22 The pair of outer rings is brought together until the elements of the
centre ring structure
23 are expanded on the wedge profiles of the outer elements. In this
condition, the first
24 expansion stage is complete, but the centre ring is not yet expanded to
its optimum outer
diameter.
26
27 The elements of the wedge ring structure 173a, 173b are symmetrical
about a centre line
28 of the ring structure, and are configured to be brought into abutment
with one another
29 under a central line under the centre segments. This design defines an
end point of the
axial travel of an outer ring structure, and prevents its elements from over-
travelling. This
31 abutment point changes the mode of travel of an outer ring from axial
displacement (during
32 which it expands an adjacent ring which is disposed towards the centre
of the apparatus
33 by a wedging action) into a tangential sliding movement of elements
within the ring, to
34 cause it to expand radially on the apparatus.
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1 The outer ring structures 173a and 173b have been brought together into
abutment, and
2 further application of an axial actuation force causes the elements of
the respective outer
3 ring structures to experience a radial force component from the wedge 175
and the wedge
4 profile 176. The radial force directs the elements of the outer ring
structures to slide with
5 respect to one another into radially expanded conditions. The radial
movement of the
6 elements of the outer rings is the same as the movement of the elements
of the centre ring
7 structure and the elements described with reference to previous
embodiments: the
8 elements slide with respect to one another in a tangential direction,
while remaining in
9 mutually supportive planar contact. As the outer ring structures expand,
a radial force is
10 imparted to the elements of the centre ring, which continue to slide
with respect to one
11 another in a tangential direction to their fully expanded condition.
12
13 The resulting expanded condition is shown in Figures 6A to 60. The
apparatus forms an
14 expanded ring structure which is solid, with no gaps between its
elements, and which has
15 a smooth circular outer surface at its full expanded condition. In
addition, both of the
16 annular surfaces or flanks of the expanded ring are smooth. The outer
diameter of the
17 expanded ring is significantly greater than the outer diameter of the
ring structures (and
18 wedges) in their collapsed state, with the increased expansion resulting
from the two stage
19 mechanism.
21 Retaining the axial force on the wedges will retain the ring structure
in an expanded
22 condition, and a reduction in the axial force to separate the wedge
profiles enables the
23 inner and outer ring structures to collapse under the retention forces
of their respective
24 spring elements.
26 Collapsing of the apparatus to a collapsed condition is achieved by
releasing the axial
27 actuation force. The sequence of collapsing is the reverse of the
expanding process: the
28 outer ring structures are collapsed first under the higher retaining
forces of their respective
29 biasing springs. Collapse of the outer rings also brings the centre ring
structure from is
fully expanded condition to an intermediate condition. Further separation of
the wedge
31 profiles collapses the centre ring structure under the retaining force
of its biasing spring,
32 back to the collapsed position shown in Figures 5A and 5B.
33
34 The principles of the two-stage expansion mechanism can be extended to
other multi-
stage expanding and collapsing apparatus. Figures 11A to 120 show such an
apparatus,
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1 which has a four-stage expansion system. Figures 11A to 110 are
respectively
2 perspective, longitudinal sectional, and end views of the apparatus in a
first, collapsed
3 condition. Figures 12A to 120 are equivalent views of the apparatus in an
expanded
4 condition. The apparatus, generally shown at 190, is similar to the
apparatus 170, and its
form and function will be understood from Figures 5 to 10 and the accompanying
6 description. However, the apparatus 190 differs in that it comprises a
centre ring structure
7 191 formed from individual elements, and three pairs of outer ring
structures 192, 193, 194
8 (each consisting of upper and lower ring structures 192a, 192b, 193a,
193b, 194a, 194b)
9 disposed on a mandrel 197 between wedge 195 and wedge profile 196.
11 In successive stages of actuation, the centre ring structure 191 is
deployed to a first
12 intermediate expanded state, and first, second, and third pairs of outer
ring structures are
13 deployed to their radially expanded states, from the inside of the
apparatus adjacent to the
14 centre ring, to the outside. At each stage, the centre ring structure is
deployed to
successive intermediate expanded states, until it is fully expanded as shown
in Figures
16 12A to 120. The outer diameter of the expanded ring is significantly
greater than the outer
17 diameter of the ring structures (and wedges) in their collapsed state,
with the increased
18 expansion resulting from the four-stage mechanism. Sequencing of the
expansion is
19 designed to be from the inside to the outside by selection of biasing
springs with
successively higher retaining forces (moving from the inside or centre of the
apparatus to
21 the outermost rings). Collapsing of the apparatus to a collapsed
condition is achieved by
22 releasing the axial actuation force, and the sequence of collapsing is
the reverse of the
23 expanding process.
24
Figures 13A to 14D show a multi-stage expanding and collapsing system in
accordance
26 with an alternative embodiment of the invention. Figures 13A and 13B are
respectively
27 perspective and longitudinal sectional views of the apparatus in a
first, collapsed condition.
28 Figures 14A and 14B are equivalent views of the apparatus in an expanded
condition;
29 Figure 140 is an end view and Figure 14D is a section through line D-D
of Figure 14B.
The apparatus, generally shown at 280, is similar to the apparatus 170 and
190, and its
31 form and function will be understood from Figures 5 to 12 and the
accompanying
32 description. However, the apparatus 280 differs in that it comprises
pars of ring structures
33 281, 282, 283 formed from individual elements with geometry different
from those of
34 previous embodiments.
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1 Figure 15 is a geometric representation of a centre element of the
apparatus of Figures
2 13A and 13B, shown from one side, and Figures 16A to 16F are respectively
first
3 perspective, second perspective, plan, first end, lower, and second end
views of a centre
4 element 284. The Figures show the inner and outer surfaces, first and
second contact
surfaces, interlocking profiles, and grooves for retaining circumferential
springs which are
6 equivalent in form and function to the features of the elements 12 and
177.
7
8 Each element is effectively a segment of a ring which has its nominal
outer diameter at the
9 optimum expansion condition of the ring, but which has been inclined at
an angle 02with
respect to a radial direction. However, in this embodiment, 02 is 90 degrees,
and a
11 shallower, finer wedge profile is created by the element. The
orientation planes of the
12 contact surfaces are tangential to the circle described by the inner
surface of the ring
13 structure in its collapsed condition. This enables optimisation of the
collapsed volume of
14 the ring structure, by reducing the size of the gaps created at the
inner surface of the ring
in the collapsed condition and enabling a more compact collapsed condition.
These
16 include the introduction of flat sections 285 at the inner surface of
the elements (visible in
17 Figure 14D), which manifest as spaces at the inner diameter of the ring
when in an
18 expanded or partially expanded condition. In the construction shown, the
profile of the
19 inner surface of the expanded ring is not critical, as the inner
diameter of the ring structure
is floating, and the true inner diameter is defined by the actuation wedge
profiles 286, 287
21 rather than the inner surface of the ring. The spaces are therefore not
detrimental to the
22 operation of the apparatus, and the apparatus benefits from a reduced
collapse volume.
23
24 The elements 284 also differ from the elements of previous embodiments
of the invention
in that the interlocking profiles formed by grooves and tongues are inverted,
such that the
26 groove 288 is in the inner surface of the element, and the tongue 289 is
in the outer
27 surface. This increases the engagement length between adjacent elements.
28
29 The elements 290 of the ring structures 282 and 283 are similarly
formed, with angle 02 at
90 degrees, with the orientation planes of their contact surfaces being
tangential to the
31 circle described by the inner surface of the ring structure in its
collapsed condition.
32
33 It should be noted that in other embodiments, different angles 02 may be
adopted,
34 including those which are in the range of 80 degrees to 90 degrees (most
preferably
tending towards 90 degrees).
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1
2 Operation of the expanding and collapsing apparatus is the same as that
described with
3 reference to Figures 11A to 120, with the centre ring structure 281 being
deployed to a
4 first intermediate expanded state, and first and second pairs of outer
ring structures being
deployed to their radially expanded states, in sequence from the inside of the
apparatus
6 adjacent to the centre ring 281, to the outside. Sequencing of the
expansion is designed
7 to be from the inside to the outside by selection of biasing springs with
successively higher
8 retaining forces (moving from the inside or centre of the apparatus to
the outermost rings).
9 Collapsing of the apparatus to a collapsed condition is achieved by
releasing the axial
actuation force, and the sequence of collapsing is the reverse of the
expanding process.
11
12 The apparatus 280, by virtue of the compact collapsed inner volumes
achievable with the
13 finer wedge profiles, is capable of increased expansion ratios. In this
example, the
14 apparatus 280 is configured to have the same expansion ratio as the
apparatus 190, with
only two pairs of expanding ring structure compared with the three pairs in
the apparatus
16 190. This reduces the axial length of the apparatus and greatly reduces
the number of
17 parts required.
18
19 The particularly high expansion ratios achieved with the multi-stage
expansion
embodiments of the invention enable application to a range of operations. For
example,
21 the apparatus may form part of a mechanically actuated, high expansion,
production
22 packer or high expansion annular flow barrier. Particular applications
include (but are not
23 limited to) cement stage packers or external casing packers for openhole
applications.
24
The expansion ratios achievable also enable use of the apparatus in through-
tubing
26 applications, in which the apparatus is required to pass through a
tubing or restriction of a
27 first inner diameter, and be expanded into contact with a tubing of a
larger inner diameter
28 at a greater depth in the wellbore. For example, the apparatus may be
used in a high
29 expansion retrievable plug, which is capable of passing through a
production tubing to set
the plug in a larger diameter liner at the tailpipe.
31
32 An alternative application of the multi-stage expansion apparatus of
Figures 5 and 6 to a
33 fluid conduit patch tool and apparatus will now be described with
reference to Figures 13A
34 to 14B. A typical patching application requires the placement and
setting of a tubular
section over a damaged part of a fluid conduit (such as a wellbore casing). A
patch tool
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29
1 comprises a tubular and a pair of setting mechanisms axially separated
positions on the
2 outside of the conduit for securing the tubular to the inside of the
fluid conduit. It is
3 desirable for the setting mechanisms to provide an effective flow
barrier, but existing patch
4 systems are often deficient in providing a fluid-tight seal with the
inner surface of the fluid
conduit, and are limited in their expansion capabilities.
6
7 Figures 13A and 13B show a high expansion patch tool, generally depicted
at 210, from
8 perspective and longitudinal sectional views shown in a collapsed, run
position. Figures
9 14A and 14B are equivalent views of the apparatus in an expanded
condition.
11 The patch tool comprises a tubular section 211, and a pair of expansion
assemblies 212a,
12 212b (together 212) in axially separated positions on the section. The
distance between
13 the assemblies 212a, 212b is selected to span the damaged section of a
fluid conduit to be
14 patched. Each of the assemblies 212 comprises a pair of expansion
apparatus 213a,
213b, disposed on either side of an elastomeric seal element 214. The
expansion
16 apparatus 213 are similar in form and function to the expansion
apparatus 170, and their
17 operation will be described with reference to Figures 5 and 6. Each
comprises a centre
18 ring structure and a pair of outer ring structures. A pair of cone wedge
members 215 is
19 provided on either side of the expansion apparatus 213.
21 The elastomeric seal elements 214 are profiled such that an axially
compressive force
22 deforms the elastomeric material, and brings first and second halves
214a, 214b of the
23 seal element together around a deformation recess 216.
24
The patch tool is, like other embodiments of the invention, configured to be
actuated by an
26 axial force. The axial force acts to radially expand the expansion
apparatus 213 in the
27 manner described with reference to Figures 5 and 6, and into contact
with the fluid conduit
28 to be patched. The elastomeric seals are deformed by the axial force via
the cone wedges
29 215, to change shape and fill an enclosed annular space formed between a
pair of
expansion apparatus 213a, 213b. The expanded condition is shown in Figures 14A
and
31 14B.
32
33 The expansion apparatus may provide sufficient frictional force with the
inner surface of
34 the conduit being patched to secure the patch tool in the conduit. This
may be facilitated
by providing engaging profiles on the expansion apparatus. For example,
unidirectional or
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1 bidirectional arrangements of ridges and grooves may be provided to
engage a
2 surrounding surface and resist movement of the apparatus. Alternatively
(or in addition),
3 separate anchor mechanisms may be provided.
4
5 The patch tool 210 provides a pair of effective seals which are fully
supported by the
6 expansion apparatus, each of which forms a solid anti-extrusion ring.
7
8 Figures 19 to 22B show a multi-stage expanding and collapsing system in
accordance with
9 an alternative embodiment of the invention. Figures 19 and 20 are
respectively side views
10 of the apparatus in a first, collapsed condition and second expanded
condition. Figures
11 21A and 21B are respectively plan and isometric views of the a first set
of elements of the
12 apparatus; Figures 22A and 22B are respectively plan and isometric views
of a second set
13 of elements of the apparatus. The apparatus, generally shown at 380, is
similar to the
14 apparatus 170, 190, and 280, with a central ring structure 381 formed
from an assembly of
15 elements 384, and two pairs of ring structures 382a, 382b (together
382), 383a and 383b
16 (together 383). The form and function of the apparatus will be
understood from Figures 5
17 to 18 and the accompanying description. However, the apparatus 380
differs in that it
18 comprises pairs of ring structures 382, 383 formed from individual
elements with geometry
19 different from those of previous embodiments.
21 Figures 21A and 21B are respectively plan and isometric views of an
element 385, from
22 which the outer ring structures 383a, 383b are assembled. Figures 22A
and 22B are
23 respectively plan and isometric views of an element 386, from which the
intermediate ring
24 structures 382a, 382b are assembled. The Figures show the outer
surfaces, first contact
surfaces, and interlocking tongues. The external profiles of the elements 385,
386 are
26 modified by provision of additional chamfers 387, 388. These chamfers
modify the
27 external profile of the elements, so that when assembled into a ring,
the inward facing
28 flank (i.e. the flank facing the centre ring) has an at least partially
smoothed conical
29 surface. This facilitates the deployment of the apparatus; the smoother
conical surface
improves the sliding action of the elements the centre ring 381 on the conical
profiles of
31 the rings 382a, 382b as the elements are brought together to expand the
centre ring.
32 Similarly, the smoothed inward facing flank of the rings 383a, 383b
facilitate the sliding of
33 the elements 382a of the rings 382a, 383b during their expansion. The
smoothed cones
34 assist a supporting ring in punching under the adjacent ring with a
smooth action,
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1 The outer surfaces 389, 390 of the elements 385, 386 are profiled such
that the ring
2 structures 382, 383 define smooth conical surfaces on their outward
facing flanks when in
3 their expanded condition. These conical surfaces combine in the
assembled, expanded
4 apparatus, to provide a substantially or fully smooth surface which is
suitable for abutment
with and/or support of an adjacent element such as an elastomer.
6
7 The elements 385, 386 also differ from the elements of previous
embodiments of the
8 invention in that the biasing means in the form of garter springs are not
mounted in
9 external grooves. Instead, apertures 391, 392 are provided in the
elements for receiving
the garter springs (or an alternative biasing means). The garter spring may be
threaded
11 through each element and then joined to make a continuous loop upon
assembly. By
12 providing the biasing means in-board of the external surface, it may be
better protected
13 from damage. In addition, the external profile of the elements is
simplified and is more
14 supportive of adjacent elements as supportive as possible. This
configuration also
facilitates location of the biasing means directly over the dovetail feature,
so that the
16 biasing force acts centrally to reduce the likelihood of canting and
jamming.
17
18 The invention may be used to provide an anti-extrusion ring or back-up
ring for a wide
19 range of expanding, radially expanding or swelling elements. For
example, the apparatus
may be used as an anti-extrusion or back-up ring for compressible, inflatable
and/or
21 swellable packer systems. Alternatively, or in addition, the expansion
apparatus may
22 provide support or back-up for any suitable flow barrier or seal element
in the fluid conduit.
23 This may function to improve the integrity of the fluid barrier or seal,
and/or enable a
24 reduction in the axial length of the seal element or flow barrier
without compromising its
functionality. A particular advantage is that equipment incorporating the
expansion
26 apparatus of the present invention can be rated to a higher maximum
working pressure.
27
28 It will be appreciated that a "single stage" expansion apparatus, for
example as described
29 with reference to Figure 1 to 4, may be used in a patch tool and method
of use. Indeed, in
some applications this may desirable, as the resulting patched tubular can
have an inner
31 diameter close to the inner diameter of the fluid conduit that has been
patched, mitigating
32 the reduction to bore size. However, the patch tool 210 has the
advantage of high
33 expansion for a slim outer diameter profile, which enables the tool to
be run through a
34 restriction in the fluid conduit, to patch a damaged part of the conduit
which has a larger
inner diameter than the restriction. For example, the patching tool could be
run through a
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32
1 part of the fluid conduit that has already been patched, either by
conventional means or by
2 a patching tool based on a single-stage expansion apparatus. Higher
expansion ratio
3 patching tools could be used, based on expansion apparatus having three
or more stage
4 deployment.
6 In the foregoing embodiments, where the expanding and collapsing
apparatus is used to
7 create a seal, the seal is typically disposed between two expanding ring
structures. In
8 alternative embodiments (not illustrated), an expanding ring structure
can be used to
9 provide a seal, or at least a restrictive flow barrier directly. To
facilitate this, the elements
which are assembled together to create the ring structures may be formed from
metal or a
11 metal alloy which is fully or partially coated or covered with a
polymeric, elastomeric or
12 rubber material. An example of such a material is a silicone polymer
coating. All surfaces
13 of the elements may be coated, for example by a dipping or spraying
process, and the
14 mutually supportive arrangement of the elements keeps them in
compression in their
operating condition. This enables the ring structures themselves to function
as flow
16 barriers, and in some applications, a seal created is sufficient to seal
against differential
17 pressures to create a seal.
18
19 Alternatively, or in addition, the elements themselves may be formed
from a compressible
and/or resilient material, such as an elastomer, rubber or polymer.
21
22 In a further alternative embodiment of the invention (not illustrated)
the characteristics of
23 the expanding/collapsing apparatus are exploited to provide a substrate
which supports a
24 seal or other deformable element. As described herein, the expanded ring
structures of
the invention provide a smooth circular cylindrical surface at their optimum
expanded
26 conditions. This facilitates their application as a functional endo-
skeleton for a surrounding
27 sheath. In one example application, a deformable elastomeric sheath is
provided over an
28 expanding ring structure 10, as described with reference to Figures 5A
to 60. When in its
29 collapsed condition, the sheath is supported by the collapsed ring
structures. The ring
structure are deployed in the manner described with reference to Figures 1 and
2, against
31 the retaining force of the circumferential spring element and any
additional retaining force
32 provided by the sheath, and the sheath is deformed to expand with the
ring structure into
33 contact with the surrounding surface. The sheath is sandwiched between
the smooth
34 outer surface of the ring structure and the surrounding surface to
create a seal.
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33
1 It will be appreciated that a multistage expanding apparatus (for example
the apparatus
2 170) could be used as an endo-skeleton to provide structural support for
components
3 other than deformable sheaths, including tubulars, expanding sleeves,
locking formations
4 and other components in fluid conduits or wellbores.
6 The multi-stage expansion apparatus of the invention may be applied to a
high expansion
7 packer or plug, and in particular a high expansion retrievable bridge
plug. The ring
8 structure may be arranged to provide a high-expansion anti-extrusion ring
for a seal
9 element of a plug. Alternatively, or in addition, elements of ring
structures of the apparatus
may be provided with engaging means to provide anchoring forces which resist
movement
11 in upward and/or downward directions. The elements of the rings
structure may therefore
12 function as slips, and may in some cases function as an integrated slip
and anti-extrusion
13 ring. Advantages over previously proposed plugs include the provision of
a highly effective
14 anti-extrusion ring; providing an integrated slip and anti-extrusion
assembly, which reduces
the axial length of the tool; providing slips with engaging surfaces which
extend around the
16 entire circumference of the tool to create an enlarged anchoring
surface, which enables a
17 reduction in the axial length of the slips for the same anchoring force;
the ability of slips of
18 a ring structure of one particular size to function effectively over a
wider range of tubular
19 inner diameters and tubing weights/wall thicknesses.
21 Alternatively or in addition, the apparatus may be used to anchor any of
a wide range of
22 tools in a wellbore, by providing the surfaces of the element with
engaging means to
23 provide anchoring forces which resist movement in upward and/or downward
directions.
24
The invention also has benefits in creating a seal and/or filling an annular
space, and an
26 additional example application is to downhole locking tools. A typical
locking tool uses one
27 or more radially expanding components deployed on a running tool. The
radially
28 expanding components engage with a pre-formed locking profile at a known
location in the
29 wellbore completion. A typical locking profile and locking mechanism
includes a recess for
mechanical engagement by the radially expanding components of the locking
tool. A seal
31 bore is typically provided in the profile, and a seal on the locking
tool is designed to seal
32 against the seal bore.
33
34 One advantage of the application of the invention to locking mechanism
is that the locking
mechanism may be provided with an integrated seal element between two
expanding sring
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34
1 structures, and does not require a seal assembly at an axially separated
point. This
2 enables a reduction in the length of the tool. The integrated seal is
surrounded at its upper
3 and lower edges by the surfaces of the ring structures, which avoid
extrusion of the seal.
4
In addition, each of the ring structures provides a smooth, unbroken
circumferential
6 surface which may engage a locking recess, providing upper and lower
annular surfaces in
7 a plane perpendicular to the longitudinal axis of the bore. This annular
surface may be
8 smooth and unbroken around the circumference of the ring structures, and
therefore the
9 lock is in full abutment with upper and lower shoulders defined in the
locking profile. This
is in contrast with conventional locking mechanisms which may only have
contact with a
11 locking profile at a number of discrete, circumferentially-separated
locations around the
12 device. The increased surface contact can support larger axial forces
being directed
13 through the lock. Alternatively, an equivalent axial support can be
provided in a lock which
14 has reduced size and/or mass.
16 Another advantage of this embodiment of the invention is that a seal
bore (i.e. the part of
17 the completion with which the elastomer creates a seal) can be recessed
in the locking
18 profile. The benefit of such configuration is that the seal bore is
protected from the
19 passage of tools and equipment through the locking profile. This avoids
impact with the
seal bore which would tend to damage the seal bore, reducing the likelihood of
reliably
21 creating a successful seal.
22
23 Similar benefits may be delivered in latching arrangements used in
connectors, such as so
24 called "quick connect" mechanisms used for latched connection of tubular
components. A
significant advantage of the invention in connection system applications is
that the
26 expansion apparatus forms a solid and smooth ring in an expanded latched
position. An
27 arrangement of radially split elements would, when expanded, form a ring
with spaces
28 between elements around their sides. In contrast, the provision of a
continuous
29 engagement surface on the expansion ring which provides full annular
contact with the
recess results in a latch capable of supporting larger axial forces. In
addition, the by
31 minimising or eliminating gaps between elements, the device is less
prone to ingress of
32 foreign matter which could impede the collapsing action of the
mechanism. These
33 principles may also be applied to subsea connectors such as tie-back
connectors, with
34 optional hydraulic actuation of their release mechanism.
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1 Additional applications of the principles of the invention include
variable diameter tools,
2 examples of which include variable diameter drift tools and variable
diameter centralising
3 tools. The position a wedge member and a cooperating surface may be
adjusted
4 continuously or to a number of discrete positions, to provide a
continuously variable
5 diameter, or a number of discrete diameters.
6
7 The invention provides an expanding and collapsing apparatus and methods
of use. The
8 apparatus comprises a plurality of elements assembled together to form a
ring structure
9 oriented in a plane around a longitudinal axis. The ring structure is
operable to be moved
10 between an expanded condition and a collapsed condition on actuation by
an axial force.
11 The plurality of elements are operable to be moved between the expanded
and collapsed
12 conditions by sliding with respect to one another in the plane of the
ring structure.
13
14 The invention provides an expanding and collapsing ring apparatus and
method of use.
15 The expanding and collapsing ring comprises a plurality of elements
assembled together
16 to form a ring structure oriented in a plane around a longitudinal axis.
The ring structure is
17 operable to be moved between a collapsed condition and a first expanded
condition by
18 movement of the plurality of elements on actuation by an axial force.
The apparatus
19 further comprises a secondary expanding and collapsing mechanism
operable to move the
20 ring structure between its collapsed condition or its first expanded
conditions to a second
21 expanded condition on actuation by an axial force. Applications of the
invention include
22 oilfield devices, including anti-extrusion rings, plugs, packers, locks,
patching tools,
23 connection systems, and variable diameter tools run in a wellbore.
24
25 The invention in its various forms benefits from the novel structure and
mechanism of the
26 apparatus. The invention also enables high expansion applications.
27
28 In addition, at an optimal expansion condition, shown in Figures 2B and
2D, the outer
29 surfaces of the individual elements combine to form a complete circle
with no gaps in
30 between the individual elements, and therefore the apparatus can be
optimised for a
31 specific diameter, to form a perfectly round expanded ring (within
manufacturing
32 tolerances) with no extrusion gaps on the inner or outer surfaces of the
ring structure.
33 The design of the expansion apparatus also has the benefit that a degree
of under
34 expansion or over expansion (for example, to a slightly different radial
position) does not
35 introduce significantly large gaps.
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36
1
2 It is a feature of the invention that the elements are mutually supported
before, throughout,
3 and after the expansion, and do not create gaps between the individual
elements during
4 expansion or at the fully expanded position. In addition, the arrangement
of elements in a
circumferential ring, and their movement in a plane perpendicular to the
longitudinal axis,
6 facilitates the provision of smooth side faces or flanks on the expanded
ring structure.
7 With deployment of the elements in the plane of the ring structure, the
width of the ring
8 structure does not change. This enables use of the apparatus in close
axial proximity to
9 other functional elements.
11 In addition, each of the ring structures provides a smooth, unbroken
circumferential
12 surface which may be used in engagement or anchoring applications,
including in plugs,
13 locks, and connectors. This may provide an increased anchoring force, or
full abutment
14 with upper and lower shoulders defined in a locking or latching profile,
enabling tools or
equipment be rated to a higher maximum working pressure.
16
17 Various modifications to the above-described embodiments may be made
within the scope
18 of the invention, and the invention extends to combinations of features
other than those
19 expressly claimed herein. In particular, the different embodiments
described herein may
be used in combination, and the features of a particular embodiment may be
used in
21 applications other than those specifically described in relation to that
embodiment.
22
