U.S. patent application number 15/419161 was filed with the patent office on 2018-08-02 for downhole swivel.
The applicant listed for this patent is TEAM OIL TOOLS, LP. Invention is credited to Anthony Nicholas Escobedo.
Application Number | 20180216417 15/419161 |
Document ID | / |
Family ID | 62977711 |
Filed Date | 2018-08-02 |
United States Patent
Application |
20180216417 |
Kind Code |
A1 |
Escobedo; Anthony Nicholas |
August 2, 2018 |
DOWNHOLE SWIVEL
Abstract
A downhole tool includes a first sub, a second sub, and a clutch
assembly positioned between the first sub and the second sub. The
clutch assembly is configured to allow rotation between the first
sub and the second sub in a first direction, and to prevent
rotation between the first sub and the second sub in a second,
opposite direction, when a compression force is applied to the
downhole tool, when a tension force is applied to the downhole
tool, and when no axial force is applied to the downhole tool.
Inventors: |
Escobedo; Anthony Nicholas;
(The Woodlands, TX) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
TEAM OIL TOOLS, LP |
The Woodlands |
TX |
US |
|
|
Family ID: |
62977711 |
Appl. No.: |
15/419161 |
Filed: |
January 30, 2017 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
E21B 17/05 20130101 |
International
Class: |
E21B 17/05 20060101
E21B017/05 |
Claims
1. A downhole tool, comprising: a first sub; a second sub; and a
clutch assembly positioned between the first sub and the second
sub, wherein the clutch assembly is configured to allow rotation
between the first sub and the second sub in a first direction, and
to prevent rotation between the first sub and the second sub in a
second, opposite direction, when a compression force is applied to
the downhole tool, when a tension force is applied to the downhole
tool, and when no axial force is applied to the downhole tool.
2. The downhole tool of claim 1, further comprising: an outer
housing that is coupled to the second sub such that the outer
housing is restrained from rotation relative to the second sub; and
an inner mandrel disposed within the outer housing and coupled to
the first sub such that the inner mandrel is restrained from
rotation relative to the first sub, wherein the clutch assembly
comprises: a body coupled to the inner mandrel, wherein one or more
tapered pockets are defined in the body; and one or more clutch
elements positioned in the one or more tapered pockets, wherein the
one or more clutch elements are configured to produce a mechanical
interference that resists rotation of the inner mandrel relative to
the outer housing in the second direction.
3. The downhole tool of claim 2, wherein the outer housing is
integrally-formed with the second sub, and wherein the body of the
clutch assembly is integrally-formed with the inner mandrel.
4. The downhole tool of claim 2, wherein the one or more clutch
elements comprise one or more cylindrical or spherical rollers.
5. The downhole tool of claim 2, wherein the clutch assembly
further comprises: a engaging member positioned partially in the
body and extending into one of the one or more pockets, wherein the
engaging member pushes against the one of the one or more clutch
elements when the first sub rotates in the first direction relative
to the second sub; and a biasing member that forces the engaging
member towards the one of the one or more pockets, to preload the
clutch assembly.
6. The downhole tool of claim 2, further comprising: a load ring
coupled to the outer housing; a first axial thrust bearing
positioned between the first sub and a first axial side of the load
ring; and a second axial thrust bearing positioned axially between
a shoulder of the inner mandrel and a second axial side of the load
ring, and radially within the outer housing.
7. The downhole tool of claim 6, further comprising a cover coupled
to the first sub and extending over the first axial thrust
bearing.
8. The downhole tool of claim 2, wherein the inner mandrel is fixed
to the first sub, and wherein the second sub is rotatable relative
to the inner mandrel.
9. A downhole tool, comprising: a first sub configured to connect
to a first tubular; a second sub configured to connect to a second
tubular; an outer housing coupled to the second sub and extending
toward and separated axially apart from the first sub; an inner
mandrel positioned at least partially within the first and second
subs, the inner mandrel being rotatable relative to the second sub
and connected to and prevented from rotating relative to the first
sub; and a clutch assembly received within the outer housing and
coupled with the inner mandrel, the clutch assembly comprising a
body having a pocket formed therein, and a clutch element movably
positioned in the pocket, wherein the clutch element permits the
inner mandrel to rotate in a first direction relative to the outer
housing and is engageable with the body and an inner diameter
surface of the outer housing to prevent rotation of the inner
mandrel relative to the outer housing in a second direction.
10. The downhole tool of claim 9, wherein the pocket has a
decreasing depth as proceeding in the first direction.
11. The downhole tool of claim 9, wherein the clutch element
comprises one or more cylindrical rollers.
12. The downhole tool of claim 9, wherein the clutch assembly
comprises one or more engaging members extending through a recess
defined in a sidewall of the pocket, wherein the one or more
engaging members engage the clutch element when the body of the
clutch assembly rotates in the first direction relative to the
outer housing.
13. The downhole tool of claim 12, wherein the clutch assembly
comprises a biasing member connected to the one or more engaging
members, the biasing member being configured to bias the engaging
member toward the clutch element, to preload the clutch
assembly.
14. The downhole tool of claim 9, further comprising: a load ring
coupled to the outer housing; and first and second axial thrust
bearings, wherein the inner mandrel comprises a shoulder, the first
axial thrust bearing being positioned between the shoulder and the
load ring, and the second axial thrust bearing being positioned
between the first sub and the load ring.
15. The downhole tool of claim 14, wherein the body of the clutch
is integral with the shoulder.
16. The downhole tool of claim 14, further comprising a radial
bearing positioned between the inner mandrel and the outer
housing.
17. The downhole tool of claim 9, wherein a plurality of pockets,
including the pocket, are defined in the body of the clutch
assembly, and wherein the clutch assembly includes a plurality of
clutch elements, including the clutch element, that are positioned
within respective ones of the plurality of pockets.
18. The downhole tool of claim 17, wherein the pockets are
positioned at approximately equal angular intervals around the body
of the clutch.
19. A method for isolating rotation in one direction and
transmitting rotation in another direction in a tubular string, the
method comprising: connecting a swivel to a tubular string, the
swivel comprising: a first sub configured to connect to a first
tubular; a second sub configured to connect to a second tubular,
wherein the second sub comprises an outer housing extending toward
and separated axially apart from the first sub; an inner mandrel
positioned at least partially within the first and second subs, the
inner mandrel being rotatable relative to the second sub and
connected to and prevented from rotating relative to the first sub;
and a clutch assembly received within the outer housing and coupled
with the inner mandrel, the clutch assembly comprising a body
having a pocket formed therein, and a clutch element movably
positioned in the pocket, wherein the clutch element permits the
inner mandrel to rotate in a first circumferential direction
relative to the outer housing and is engageable with the body and
an inner diameter surface of the outer housing to prevent rotation
of the inner mandrel relative to the outer housing in a second
circumferential direction. deploying the tubular string and the
swivel into a well; rotating the tubular string in the first
circumferential direction, wherein the rotation in the first
circumferential direction causes first sub to rotate relative to
the second sub; and rotating the tubular string in the second
circumferential direction, wherein the rotation in the second
circumferential direction causes the clutch assembly to engage the
body and the outer housing, such that the first and second subs to
rotate together.
20. The method of claim 19, wherein the swivel comprises a
plurality of pockets, including the pocket, are defined in the body
of the clutch assembly, and wherein the clutch assembly includes a
plurality of clutch elements, including the clutch element, that
are positioned within respective ones of the plurality of pockets,
and wherein, when rotating the tubular string in the second
circumferential direction, the plurality of clutch elements engage
the outer housing and prevent relative rotation therebetween.
Description
BACKGROUND
[0001] In the oil and gas industry, downhole swivels are employed
to isolate rotation of a string of tubulars (e.g., casing) from a
tool connected to the string. In other words, the swivel allows for
relative rotation between two sections of the string of tubulars.
Swivels come in a variety of configurations and are implemented
across a wide range of applications. Generally, swivels include at
least a pair of cylindrical bodies, which are relatively rotatable,
e.g., by provision of a bearing. Some types of swivels also include
a clutch, which allows one-way rotation between the cylindrical
bodies, while preventing reverse rotation. Such one-way swivels can
be useful when casing rotation is employed to actuate a mechanism
downhole, for example. Thus, the swivel transmits the rotation from
the tubular string to the tool in one direction, while allowing
relative rotation of the string and the tool in the opposite
direction.
[0002] Generally, such clutches are implemented with meshing teeth,
i.e., a ratchet. Angled surfaces of the teeth force the teeth of a
radially inner body to slide out of engagement with a tooth of an
outer body, and then into engagement with the next succeeding
tooth. Backwards rotation is prevented as the back-sides of the
teeth are typically flat, and thus circumferential forces are not
translated into the radial force that allows the teeth to move.
Further, the swivels are typically made to operate either in
compression or tension in the drill string. When the
opposite-oriented force is applied to the swivel (e.g., tension is
applied to a compression swivel) the teeth of the clutch can
disengage, axially separating apart and thereby allowing for free
rotation in either direction. In some situations, however, it would
be beneficial to employ a swivel having a clutch that is operable
both in compression and in tension.
SUMMARY
[0003] Embodiments of the disclosure may provide a downhole tool
including a first sub, a second sub, and a clutch assembly
positioned between the first sub and the second sub. The clutch
assembly is configured to allow rotation between the first sub and
the second sub in a first direction, and to prevent rotation
between the first sub and the second sub in a second, opposite
direction, when a compression force is applied to the downhole
tool, when a tension force is applied to the downhole tool, and
when no axial force is applied to the downhole tool.
[0004] Embodiments of the disclosure may also provide a downhole
tool that includes a first sub configured to connect to a first
tubular, a second sub configured to connect to a second tubular,
and an outer housing coupled to the second sub and extending toward
and separated axially apart from the first sub. The tool also
includes an inner mandrel positioned at least partially within the
first and second subs, the inner mandrel being rotatable relative
to the second sub and connected to and prevented from rotating
relative to the first sub. The tool further includes a clutch
assembly received within the outer housing and coupled with the
inner mandrel, the clutch assembly including a body having a pocket
formed therein, and a clutch element movably positioned in the
pocket. The clutch element permits the inner mandrel to rotate in a
first direction relative to the outer housing and is engageable
with the body and an inner diameter surface of the outer housing to
prevent rotation of the inner mandrel relative to the outer housing
in a second direction.
[0005] Embodiments of the disclosure may also provide a method for
isolating rotation in one direction and transmitting rotation in
another direction in a tubular string. The method includes
connecting a swivel to a tubular string. The swivel includes a
first sub configured to connect to a first tubular, and a second
sub configured to connect to a second tubular. The second sub
includes an outer housing extending toward and separated axially
apart from the first sub. The swivel also includes an inner mandrel
positioned at least partially within the first and second subs, the
inner mandrel being rotatable relative to the second sub and
connected to and prevented from rotating relative to the first sub.
The swivel further includes a clutch assembly received within the
outer housing and coupled with the inner mandrel, the clutch
assembly including a body having a pocket formed therein, and a
clutch element movably positioned in the pocket. The clutch element
permits the inner mandrel to rotate in a first circumferential
direction relative to the outer housing and is engageable with the
body and an inner diameter surface of the outer housing to prevent
rotation of the inner mandrel relative to the outer housing in a
second circumferential direction. The method also includes
deploying the tubular string and the swivel into a well, and
rotating the tubular string in the first circumferential direction.
The rotation in the first circumferential direction causes first
sub to rotate relative to the second sub. The method further
includes rotating the tubular string in the second circumferential
direction. The rotation in the second circumferential direction
causes the clutch assembly to engage the body and the outer
housing, such that the first and second subs to rotate
together.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] The present disclosure may best be understood by referring
to the following description and accompanying drawings that are
used to illustrate embodiments of the invention. In the
drawings:
[0007] FIG. 1 illustrates a side, cross-sectional view of a
downhole tool, e.g., a swivel, according to an embodiment.
[0008] FIG. 2 illustrates a raised perspective view of the downhole
tool, according to an embodiment.
[0009] FIG. 3 illustrates a sectional view of the downhole tool,
according to an embodiment.
[0010] FIG. 4 illustrates a raised perspective view of a portion of
the downhole tool, according to an embodiment.
[0011] FIG. 5 illustrates a flowchart of a method for isolating
rotation in one direction and transmitting rotation in another
direction in a tubular string, according to an embodiment.
DETAILED DESCRIPTION
[0012] The following disclosure describes several embodiments for
implementing different features, structures, or functions of the
invention. Embodiments of components, arrangements, and
configurations are described below to simplify the present
disclosure; however, these embodiments are provided merely as
examples and are not intended to limit the scope of the invention.
Additionally, the present disclosure may repeat reference
characters (e.g., numerals) and/or letters in the various
embodiments and across the Figures provided herein. This repetition
is for the purpose of simplicity and clarity and does not in itself
dictate a relationship between the various embodiments and/or
configurations discussed in the Figures. Moreover, the formation of
a first feature over or on a second feature in the description that
follows may include embodiments in which the first and second
features are formed in direct contact, and may also include
embodiments in which additional features may be formed interposing
the first and second features, such that the first and second
features may not be in direct contact. The embodiments presented
below may be combined in any combination of ways, e.g., any element
from one exemplary embodiment may be used in any other exemplary
embodiment, without departing from the scope of the disclosure.
[0013] Additionally, certain terms are used throughout the
following description and claims to refer to particular components.
As one skilled in the art will appreciate, various entities may
refer to the same component by different names, and as such, the
naming convention for the elements described herein is not intended
to limit the scope of the invention, unless otherwise specifically
defined herein. Further, the naming convention used herein is not
intended to distinguish between components that differ in name but
not function. Additionally, in the following discussion and in the
claims, the terms "including" and "comprising" are used in an
open-ended fashion, and thus should be interpreted to mean
"including, but not limited to." All numerical values in this
disclosure may be exact or approximate values unless otherwise
specifically stated. Accordingly, various embodiments of the
disclosure may deviate from the numbers, values, and ranges
disclosed herein without departing from the intended scope.
Finally, unless otherwise provided herein, "or" statements are
intended to be non-exclusive; for example, the statement "A or B"
should be considered to mean "A, B, or both A and B."
[0014] Embodiments of the present disclosure may provide a downhole
tool, configured as a casing swivel (or another type of downhole,
oilfield swivel) that is provided with a clutch assembly. The
clutch assembly is operable to allow one-way rotation, while
preventing rotation in the opposite direction, regardless of
whether compressive or tensile loads are applied to the tool. In
particular, the disclosed downhole tool may be operable at high
dynamic and static loads, e.g., up to about 100,000 pounds of
dynamic load and 400,000 pounds of static load.
[0015] FIG. 1 illustrates a cross-sectional, side view of a
downhole tool 100, according to an embodiment. The downhole tool
100 may be configured as a swivel, such as for isolating rotation
between an oilfield tubular (e.g., casing, liner, etc.) coupled to
the tool 100 and another tubular (e.g., part of a separate downhole
tool) that is coupled to the tool 100. This is but one example of
the implementation of this tool 100, however, and other
implementations will be apparent to one of ordinary skill in the
art.
[0016] The downhole tool 100 may include a first or "upper" sub
102, a second or "lower" sub 104, which may be spaced axially
apart, such that the first and second subs 102, 104 are rotatable
relative to one another, as will be described in greater detail
below. The first sub 102 may be connected to an end of a tubular,
such as a rotatable string of oilfield tubulars (e.g., a casing
string), while the second sub 104 may be connected to another
tubular, such as another part of the string of oilfield tubulars,
or part of another tool or device. An inner mandrel 106 may extend
between the first and second subs 102, 104. For example, the inner
mandrel 106 may be coupled to the first sub 102, such that relative
rotation therebetween is prevented. In a specific embodiment, the
inner mandrel 106 may be threaded into the first sub 102, but, in
other embodiments, the inner mandrel 106 may be coupled to the
first sub 102 in a variety of ways (e.g., pinned, welded, brazed,
press fit, etc.). The inner mandrel 106 may be coupled to the
second sub 104 such that the second sub 104 is rotatable relative
to the inner mandrel 106. For example, the inner mandrel 106 may be
received into the second sub 104, and one or more seals 108 (four
are shown) may be positioned in the second sub 104 (and/or in the
inner mandrel 106) so as to prevent the flow of fluid or migration
of debris therebetween.
[0017] The first sub 102 may define a bore 110, the inner mandrel
106 may define a bore 112, and the second sub 104 may define a bore
114. In an embodiment, either or both of the bores 110, 112 in the
first and second subs 102, 104, respectively, may be
recessed/undercut, so as to account for a radial thickness of the
inner mandrel 106. Accordingly, as shown, the bores 110, 112, 114
may define a substantially constant inner diameter throughout the
tool 100. In other embodiments, the diameter may change as
proceeding through the tool 100.
[0018] The tool 100 may include an outer housing 116. The outer
housing 116 may be integrally formed with the second sub 104, such
that the two pieces form a single, monolithic part. In another
embodiment, the outer housing 116 may be connected to the second
sub 104, e.g., using fasteners, welding, brazing, etc. Either such
configuration (integral formation or connection) is considered
within the scope of "coupled to" as the term is used herein.
Further, in either such configuration, the outer housing 116 may be
generally prevented from rotation relative to (a remainder of) the
second sub 104. The outer housing 116 may be generally shaped as a
cylindrical sleeve and may extend axially toward the first sub 102.
The outer housing 116 may be separated axially apart from the first
sub 102, however, so as to allow for relative rotation
therebetween. Further, the inner mandrel 106 and the outer housing
116 may be separated radially apart, such that a first annular
chamber 118 is defined therebetween. As shown, the first annular
chamber 118 may be formed by two or more separate sub-chambers
(e.g., on either side of a shoulder 130 of the inner mandrel 106,
as will be described below).
[0019] The tool 100 may include a cover 120, which may be coupled
to the first sub 102 and may extend axially therefrom, toward the
second sub 104. The cover 120 may be spaced axially apart from the
outer housing 116, allowing for rotation therebetween. The cover
120 may be spaced radially apart from the inner mandrel 106, such
that a second annular chamber 122 is defined therebetween.
[0020] The tool 100 may include one or more axial thrust bearings
(two are shown: a first axial thrust bearing 124 and a second axial
thrust bearing 126). In embodiments including first and second
axial thrust bearings 124, 126, a load ring 128 may be interposed
axially between the first and second axial thrust bearings 124,
126. For example, the load ring 128 may be received around the
inner mandrel 106 and threaded (or otherwise coupled) to the outer
housing 116 so as to rotate with the second sub 104. In an
embodiment, the first axial thrust bearing 124 may be received in
the first annular chamber 118, between the outer housing 116 and
the inner mandrel 106, and the second axial thrust bearing 126 may
be received in the second annular chamber 122 between the cover 120
and the inner mandrel 106. Further, the first axial thrust bearing
124 may be configured to engage the load ring 128 on one axial side
and the shoulder 130 of the inner mandrel 106 on an opposite axial
side. The shoulder 130 may extend radially outwards into proximity
of the outer housing 116. In some embodiments, the shoulder 130 may
slide against the outer housing 116. The second axial thrust
bearing 126 may be configured to engage the load ring 128 on one
axial side and the first sub 102 on the opposite axial side.
[0021] In an embodiment, one of the axial thrust bearings 124, 126
may be provided to facilitate rotation between the first and second
subs 102, 104 under compressive loads (e.g., the first sub 102 and
the second sub 104 being pushed together), and the other one of the
axial thrust bearings 124, 126 may be provided to facilitate
rotation between the first and second subs 102, 104 under tensile
loads (e.g., the first sub 102 and the second sub 104 being pulled
apart). The axial thrust bearings 124, 126 may be any suitable type
of thrust bearings, with the ability to support the dynamic and
static loads called for by the specific application.
[0022] The tool 100 may include one or more radial bearings (one
shown: 132). The radial bearing 132 may be positioned in the first
annular chamber 118, e.g., on an opposite side of the shoulder 130
from the first axial thrust bearing 124. In some embodiments,
another radial bearing may be positioned on an opposite side of the
load ring 128 and/or in the second annular chamber 122. The radial
bearing 132 may be a plain bearing (e.g., a bushing-type bearing),
but could also be a roller bearing or any other suitable bearing,
e.g., depending on size constraints. The radial bearing 132 may be
positioned between the inner mandrel 106 and the outer housing 116,
so as to facilitate rotation therebetween and, e.g., support
bending forces applied to the tool 100.
[0023] The tool 100 may include a clutch assembly 200. The clutch
assembly 200 may be connected to or formed generally as a part of
the inner mandrel 106, e.g., disposed in the shoulder 130. In other
embodiments, the clutch assembly 200 may be a separate piece from
the inner mandrel 106 and may be connected thereto. The clutch
assembly 200 may allow rotation of the second sub 104 with respect
to the first sub 102 in a first direction, while preventing
rotation therebetween in a second, opposing direction. For example,
the clutch assembly 200 may lock the inner mandrel 106 from
rotation with respect to the outer housing 116 in the second
direction, as explained in greater detail below. The clutch
assembly 200 may be continuously engaged, meaning that it functions
to prevent rotation in the second direction regardless of whether
the tool 100 is in compression, tension, or no axially-directed
load.
[0024] FIG. 2 illustrates a raised perspective view of the tool
100, according to an embodiment, with the outer housing 116 omitted
for the sake of clarity. As shown, the tool 100 includes the first
sub 102, the axial thrust bearings 124, 126, the load ring 128, the
inner mandrel 106 with the shoulder 130, the radial bearing 132,
and the clutch assembly 200. In this view, the second sub 104 is
removed for purposes of illustration.
[0025] In an embodiment, the clutch assembly 200 includes a clutch
body 201 in which a plurality of pockets 202 are formed. In some
embodiments, the clutch body 201 may be integral with (formed as a
part of) the shoulder 130 of the inner mandrel 106, but in other
embodiments, may be provided by a separate (e.g., ring-shaped)
structure that is connected to the inner mandrel 106. The clutch
assembly 200 also includes a plurality of clutch elements 204
positioned in the pockets 202 (e.g., one clutch element 204 per
pocket 202, although two or more clutch elements 204 could be
provided in a single pocket 202, and/or one or more pockets 202 may
not include a clutch element 204). In some embodiments, the clutch
elements 204 may be rollers, such as cylindrical dowels or
spherical members. In other embodiments, the clutch elements 204
may be generally wedge-shaped.
[0026] FIG. 3 illustrates a sectional view, generally along line
3-3 in FIG. 2, of the tool 100, showing the clutch assembly 200 in
greater detail, according to an embodiment. FIG. 3 also illustrates
the outer housing 116 as transparent, and the cover 120 as opaque,
which are not shown in FIG. 2.
[0027] The pockets 202 may be flat sections, e.g., machined into
the clutch body 201. Accordingly, in some embodiments, the pockets
202 may be formed as a flat cut out in the circumferential surface
of the clutch body 201, such that a depth from the bottom 300 of
the pocket 202 to the outer diameter of the clutch body 201
decreases as proceeding in a first circumferential direction (e.g.,
the counterclockwise direction as shown in FIG. 3).
[0028] Optionally, one or more engaging members 302 (two are shown
in each pocket 202 in this example) may extend into each of the
pockets 202 from a recess 304 formed in a sidewall 306 thereof. The
engaging members 302 may be, in some embodiments, generally
cylindrical plungers designed to push against the clutch elements
204. A biasing member 308 may be positioned in the recess 304 and
may be configured to bias the engaging member 302 into the pocket
202. For example, the biasing member 308 may fit at least partially
within, or around an end of, the engaging member 302, and push the
engaging member 302 into the pocket 202. The biasing member 308 may
be a coiled compression spring, a leaf spring, Bellville washer,
etc. In some embodiments, the biasing member 308 and/or the
engaging members 302 may be omitted. The engaging members 302 may
bear against the clutch elements 204, generally preventing the
clutch elements 204 from engaging the sidewall 306 and, in some
embodiments, preloading the clutch elements 204 against the outer
housing 116.
[0029] As shown, the pockets 202 may be disposed at intervals
(e.g., equiangularly) around the shoulder 130, such that the
shoulder 130 resembles a toothed structure. The actual number of
pockets 202 may vary, e.g., from two to about ten, or more,
depending on the implementation. In some embodiments, an even
number of pockets 202 (and clutch elements 204) may be provided to
radial forces incident on the shoulder 130, as will be described in
greater detail below.
[0030] FIG. 4 illustrates a raised perspective view of a portion of
the tool 100, showing the clutch assembly 200 through the outer
housing 116, which is illustrated in phantom for the sake of
describing the clutch assembly 200, according to an embodiment. In
particular, operation of the clutch assembly 200 may be appreciated
with reference to FIG. 4.
[0031] The clutch elements 204 may be slightly smaller or larger in
radial dimension (e.g., in the illustrated cylindrical clutch
elements 204, the radial dimension is the diameter of the
individual clutch elements 204) than the depth of the pocket 202 at
the sidewall 306. Accordingly, the engaging members 302 may apply a
small force on the clutch elements 204, pushing the clutch elements
204 away from the sidewall 306 until the clutch elements 204
engage, or nearly engage, the outer housing 116, thereby preloading
the clutch assembly 200. When the first sub 102 (and thus the inner
mandrel 106--see FIG. 1--including the shoulder 130) rotates in a
first direction D1 relative to the outer housing 116 (which also
describes the outer housing 116 rotating in a second direction D2
relative to the inner mandrel 106), engagement between the clutch
elements 204 and the outer housing 116 may push the clutch elements
204 against the engaging members 302, such that the clutch elements
204 may generally continuously engage the outer housing 116,
without impeding rotation in the first direction D1. Accordingly,
the clutch assembly 200 permits the inner mandrel 106 (and thus the
first sub 102) to rotate freely in the first direction D1 relative
to the outer housing 116 and the second sub 104.
[0032] In contrast, when the first sub 102, and thus the clutch
body 201, rotates in the second, opposite direction D2 with respect
to the outer housing 116, the engagement between the outer housing
116 and the clutch elements 204 moves the clutch elements 204 away
from the sidewall 306, into the shallower region of the tapered
pocket 202. As the clutch elements 204 move away from the sidewall
306, eventually, the clutch elements 204 produce a mechanical
interference between the body 201 and the outer housing 116 as the
clutch elements 204 wedge between the outer housing 116 and the
bottom 300 of the pockets 202. Such interference/wedging acts to
resist and ultimately prevent relative rotation in the second
direction D2 of the clutch body 201 (and thus the inner mandrel 106
and thus the first sub 102) with respect to the outer housing 116
(and thus the second sub 104). The spring-biased engaging members
302 may serve to ensure generally simultaneous engagement between
the multiple clutch elements 204 and the outer housing 116, so as
to balance radial forces.
[0033] Accordingly, the clutch assembly 200 is continuously
engaged, regardless of whether the axial thrust bearings 124, 126
take up axial compressive and tensile loads. This construction
allows such functioning as there is no corresponding clutch
structure in the outer housing 116; rather, the clutch assembly 200
interfaces with the inner diameter surface of the outer housing 116
to provide the clutching function. This contrasts with saw-tooth
type clutches, which typically disengage in either compressive or
tensile loads.
[0034] FIG. 5 illustrates a flowchart of a method 500 for isolating
rotation in one direction and transmitting rotation in another
direction in a tubular string, according to an embodiment. The
method 500 may proceed by operation of one or more embodiments of
the downhole tool 100 (e.g., casing swivel) discussed and described
above, but is not limited to any particular structure unless
otherwise stated herein.
[0035] The method 500 may begin by connecting a swivel (e.g., the
downhole tool 100) to a tubular string, as at 502. The swivel may
be constructed according to any of the embodiments discussed above
with respect to the downhole tool 100, or others. The method 500
may then proceed to deploying the tubular string and the swivel
into a well, as at 504.
[0036] The method 500 may further include rotating the tubular
string while applying tension or compression thereto, in the first
circumferential direction, as at 506. The rotation in the first
circumferential direction D1 causes first sub 102 to rotate
relative to the second sub 104, which is allowed by the clutch
assembly 200, as explained above.
[0037] The method 500 may also include rotating the tubular string
while applying tension or compression thereto, in the second
circumferential direction D2, as at 508. Rotation in the second
circumferential direction D2 causes the clutch elements 204 of the
clutch assembly 200 to engage the body 201 and the outer housing
116, such that the first and second subs 102, 104 are prevented
from relative rotation, and are thus caused to rotate together by
rotation of the tubular string.
[0038] As used herein, the terms "inner" and "outer"; "up" and
"down"; "upper" and "lower"; "upward" and "downward"; "above" and
"below"; "inward" and "outward"; "uphole" and "downhole"; and other
like terms as used herein refer to relative positions to one
another and are not intended to denote a particular direction or
spatial orientation. The terms "couple," "coupled," "connect,"
"connection," "connected," "in connection with," and "connecting"
refer to "in direct connection with" or "in connection with via one
or more intermediate elements or members."
[0039] The foregoing has outlined features of several embodiments
so that those skilled in the art may better understand the present
disclosure. Those skilled in the art should appreciate that they
may readily use the present disclosure as a basis for designing or
modifying other processes and structures for carrying out the same
purposes and/or achieving the same advantages of the embodiments
introduced herein. Those skilled in the art should also realize
that such equivalent constructions do not depart from the spirit
and scope of the present disclosure, and that they may make various
changes, substitutions, and alterations herein without departing
from the spirit and scope of the present disclosure.
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