Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
SLIPS WITH INTERNAL BUTTONS
RELATED APPLICATIONS
[0001] This application is related to the U.S. non-provisional utility
patent application titled
"COMPACT DOWNHOLE TOOL", attorney docket number NSC100/4-013US, filed
concurrently herewith and hereby incorporated by reference in its entirety
herein.
BACKGROUND
Field of the Disclosure
[0002] The present disclosure relates generally to parts used in downhole
assemblies and, more
particularly, to a slip with internal buttons for use in a downhole assembly.
Description of the Related Art
[0003] During drilling or reworking of wells, tubing or other pipe (e.g.,
casing) in the wellbore
may be sealed at a particular location, such as for pumping cement or other
fluids down the tubing,
and forcing fluid out into a formation. Various downhole tools have been
designed to effect this
sealing or to isolate a particular zone of the wellbore. Many such downhole
tools used for sealing
a wellbore employ slips to contact casing in the wellbore with sufficient
friction under pressure to
hold the downhole tool in place and maintain the seal in the wellbore for the
desired application.
[0004] Multiple slips may be arranged around an exterior surface of a
cylindrically-shaped
downhole tool, and are pushed outward by a cone in the downhole tool that
moves the slips to be
in contact with a surface of the wellbore, such as the wall of the wellbore or
casing within a
wellbore, when the downhole tool is set. Typical slips may be equipped with
buttons on the
exterior surface to increase the friction between the slip and the surface of
the wellbore.
[0005] Various types of downhole tools may also employ an elastomeric
member and spherical
element with a cone and slip arrangement to effect a seal in the wellbore,
such as packers, bridge
plugs, and frac plugs. In a frac plug, the slips hold the elastomeric member
of the frac plug in
place against the wellbore when the frac plug is set and may enable the frac
plug to withstand a
certain amount of pressure or flow rate while maintaining the seal in the
wellbore and holding the
frac plug in place. Certain frac plugs may further be enabled to remain in the
wellbore and held
in place by slips during production from the well.
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SUMMARY
[0006] In one aspect, a slip having internal buttons is disclosed. The slip
may include an outer
surface enabled to engage a wellbore surface, and an inner surface enabled to
be engaged by a
setting cone of a downhole tool. In the slip, the inner surface may include at
least one inner button
enabled to contact the setting cone when the setting cone engages the inner
surface.
[0007] In any of the disclosed embodiments of the slip, the outer surface
may include at least
one outer button enabled to contact the wellbore surface.
[0008] In any of the disclosed embodiments of the slip, the inner button
may include a material
that has a higher coefficient of friction than the coefficient of friction of
the inner surface of the
slip when in contact with the setting cone.
[0009] In any of the disclosed embodiments of the slip, the inner surface
of the slip in the
downhole tool may be parallel to the setting cone.
[0010] In any of the disclosed embodiments of the slip, an exposed surface
of the inner button
facing the setting cone may be non-parallel with the setting cone.
[0011] In any of the disclosed embodiments of the slip, the setting cone
may include a metal
and the inner button may include a non-metal. In the slip, the inner button
may include a composite
material including at least one non-metal. In the slip, the inner button may
include a metal.
[0012] In any of the disclosed embodiments of the slip, the inner button
may be substantially
cylindrical in shape.
[0013] In any of the disclosed embodiments of the slip, the inner button
may be shaped
substantially as a polygonal prism.
[0014] In any of the disclosed embodiments of the slip, an exposed surface
of the inner button
that faces a surface of the setting cone may be non-parallel with the surface
of the setting cone.
[0015] In any of the disclosed embodiments of the slip, an exposed surface
of the inner button
that faces a surface of the setting cone may be parallel with the surface of
the setting cone.
[0016] In any of the disclosed embodiments of the slip, the wellbore
surface may be a casing.
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[0017] In another aspect, a downhole tool is disclosed. The downhole tool
may include a
setting cone enabled to engage a plurality of slips located circumferentially
about the setting cone
when the downhole tool is set. In the downhole tool, the slips may further
include an external
surface enabled to engage a casing when the downhole tool is set, and an
internal surface enabled
to engage the setting cone when the downhole tool is set. In the downhole
tool, at least one of the
slips may further include the internal surface of the slip including at least
one internal button
enabled to contact the setting cone when the downhole tool is set.
[0018] In any of the disclosed embodiments of the downhole tool, the
external surface of the
slip may include at least one exterior button enabled to contact the casing.
[0019] In any of the disclosed embodiments of the downhole tool, the
internal button may
include a material that has a higher coefficient of friction than the
coefficient of friction of the
internal surface of the slip when in contact with the setting cone.
[0020] In any of the disclosed embodiments of the downhole tool, the
setting cone may include
a metal, and the internal button comprises a non-metal.
[0021] In any of the disclosed embodiments of the downhole tool, the
internal button may
include a composite material including at least one non-metal. In the downhole
tool, the internal
button may include a metal.
[0022] In any of the disclosed embodiments of the downhole tool, the
internal surface of the
slip may be parallel to the setting cone.
[0023] In any of the disclosed embodiments of the downhole tool, an exposed
surface of the
internal button that faces a surface of the setting cone may be non-parallel
with the surface of the
setting cone.
[0024] In any of the disclosed embodiments of the downhole tool, an exposed
surface of the
internal button that faces a surface of the setting cone may be parallel with
the surface of the setting
cone.
[0025] In any of the disclosed embodiments of the downhole tool, the
internal button may be
substantially cylindrical in shape.
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[0026] In any of the disclosed embodiments of the downhole tool, the
internal button may be
shaped substantially as a polygonal prism.
[0027] In yet another aspect, a method for engaging downhole tools in
wellbores is disclosed.
The method may include running a downhole tool to a depth in a casing. In the
method, the
downhole tool may include a setting cone enabled to engage a plurality of
slips located
circumferentially about the setting cone when the downhole tool is set. The
method may further
include setting the downhole tool in the casing, including causing the
plurality of slips to engage
a setting cone. In the method, the slips may further include an outer surface
enabled to engage the
casing when the downhole tool is set, and an inner surface enabled to engage
the setting cone when
the downhole tool is set. In the method, at least one of the slips may be an
inner button slip that
may further include the inner surface of the slip including at least one inner
button. In the method,
causing the plurality of slips to engage the setting cone may further include
forcing the plurality
of slips against the setting cone. In the method, the plurality of slips may
include the at least one
inner button slip, while the inner button may contact the setting cone as the
plurality of slips engage
the casing.
[0028] In any of the disclosed embodiments of the method, the plurality of
slips engaging the
setting cone may further include at least one outer button located at the
outer surface of the slip
engaging the casing.
[0029] In any of the disclosed embodiments of the method, the inner button
may further
include a material that has a higher coefficient of friction than the
coefficient of friction of the
inner surface of the slip when in contact with the setting cone.
[0030] In any of the disclosed embodiments of the method, the setting cone
may include a
metal, while the inner button may include a non-metal.
[0031] In any of the disclosed embodiments of the method, the inner button
may include a
composite material including at least one non-metal. In any of the disclosed
embodiments of the
method, the inner button may include a metal.
[0032] In any of the disclosed embodiments of the method, the inner surface
of the slip may
be parallel to the setting cone in the downhole tool.
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[0033] In any of the disclosed embodiments of the method, an exposed
surface of the inner
button that faces a surface of the setting cone may be non-parallel with the
surface of the setting
cone.
[0034] In any of the disclosed embodiments of the method, an exposed
surface of the inner
button that faces a surface of the setting cone may be parallel with the
surface of the setting cone.
[0035] In any of the disclosed embodiments of the method, the inner button
may be
substantially cylindrical in shape.
[0036] In any of the disclosed embodiments of the method, the inner button
may be shaped
substantially as a polygonal prism.
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BRIEF DESCRIPTION OF THE DRAWINGS
[0037] For a more complete understanding of the present disclosure and its
features and
advantages, reference is now made to the following description, taken in
conjunction with the
accompanying drawings, in which:
[0038] FIGURE 1 is a depiction of a frac plug having slips with internal
buttons;
[0039] FIGURE 2 is a partial sectional view of slip loading with an
internal button;
[0040] FIGURE 3 is a flow chart of a method using a slip with internal
buttons;
[0041] FIGURE 4A is a depiction of a frac plug having slips with internal
buttons; and
[0042] FIGURE 4B is a depiction of a frac plug having slips with internal
buttons.
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DESCRIPTION OF PARTICULAR EMBODIMENT(S)
[0043] In the following description, details are set forth by way of
example to facilitate
discussion of the disclosed subject matter. It should be apparent to a person
of ordinary skill in
the field, however, that the disclosed embodiments are exemplary and not
exhaustive of all
possible embodiments.
[0044] Throughout this disclosure, a hyphenated form of a reference numeral
refers to a
specific instance of an element and the un-hyphenated form of the reference
numeral refers to the
element generically or collectively. Thus, as an example (not shown in the
drawings), device "12-
1" refers to an instance of a device class, which may be referred to
collectively as devices "12"
and any one of which may be referred to generically as a device "12". In the
figures and the
description, like numerals are intended to represent like elements.
[0045] As noted above, slips are parts in downhole tools, such as packers,
bridge plugs, and
frac plugs, among others, that may be used for anchoring against a surface of
a wellbore, typically
by using a cone-shaped member to force the slips against the surface of a
wellbore. The gripping
force that the slips are capable of exerting can be a key factor in the design
and implementation of
the downhole tool. The frictional performance of the slip may be determinative
for the strength of
the seal formed by the downhole tool and the amount of pressure that the seal
and the downhole
tool can withstand. Seals and downhole tools that can withstand higher
pressures or higher flow
rates are desirable because they enable wider ranges of operating conditions
for well operators.
Accordingly, slips having hard external or exterior buttons, such as ceramic
buttons, have been
used to improve the coefficient of friction between the slip and the casing,
thereby improving the
frictional force applied by the slip.
[0046] As will be disclosed in further detail herein, a slip with internal
buttons for use in a
downhole assembly, such as in a downhole tool, is disclosed. The slip with
internal buttons for
use in a downhole assembly disclosed herein may enable an increased frictional
force between the
slip and a setting cone in a downhole tool, for example. Accordingly, the slip
with internal buttons
for use in a downhole assembly disclosed herein may enable an improved design
for a downhole
tool, such as by using a single setting cone with slips in the downhole tool
instead of a pair of
setting cones with respective pairs of slips, which may enable a substantially
more compact
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downhole tool for a given frictional force, which is desirable. The slip with
internal buttons for
use in a downhole assembly disclosed herein may be implemented using a variety
of materials for
the slip body and for the internal buttons, as disclosed herein.
[0047] Referring now to the drawings, FIGURE 1 shows a portion of a frac
plug 100 having
slips 104. FIGURE 1 is a schematic diagram for descriptive purposes and is not
drawn to scale or
perspective. In FIGURE 1, the depicted portion of frac plug 100 includes a
setting cone 106 (or
simply, cone 106). In particular embodiments, cone 106 may have a
frustoconical shape. Frac
plug 100 may operate to plug a wellbore, such as a cased wellbore having a
casing diameter of 3.5
inches, 4 inches, 4.5 inches, or 5.5 inches, among other casing diameters. It
will be understood
that frac plug 100 may include other elements, such as additional sets of
setting cones and
corresponding slips, in various embodiments. For example in some embodiments,
frac plug 100
may include an elastomeric member that expands to seal the casing diameter
when frac plug 100
is set in place. Frac plug 100 may be set in place by compressing frac plug
100, such that slips
104 are engaged to firmly hold frac plug 100 in a particular location in a
corresponding wellbore,
such as within a casing of the wellbore. The frictional force of slips 104
pressing against the
interior surface of the wellbore (or the casing) holds frac plug 100 in place
in the set or "plugged"
condition. Accordingly, the force that maintains frac plug 100 in the set or
plugged condition is
achieved by virtue of the material strength of slips 104 as well as a
frictional force between slips
104 and cone 106.
[0048] As shown in FIGURE 1, in frac plug 100, cone 106 is located adjacent
to slips 104,
which may be a plurality of parts arranged axially next to each other and may
be bound together
with at least one ring clamp (not shown) prior to downhole introduction and
engagement. When
slips 104 are forced against cone 106 in the direction given by arrow 120
(i.e., the frac plug is
compressed), cone 106 works with appreciable force against an inner surface of
each individual
composite slip 104, which may cause a ring clamp to fail and to release slips
104. Because slips
104 are nonetheless contained in the downhole setting, slips 104 are forced
outward to press against
the wellbore or the casing. Also shown are ceramic buttons 110, which may be
embedded at an
outer surface of slips 104 to provide increased friction and hardness to
improve the securing of
frac plug 100 by slips 104. As will be described in further detail, slips 104
may have internal (or
inner) buttons (not visible in FIGURE 1, see FIGURES 2 and 4B), as disclosed
herein, that provide
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increased friction and hardness to improve the engagement of cone 106 against
an internal (or
inner) surface of slips 104.
[0049] Although a frac plug 100 is shown incorporating slips 104, it will
be understood that
other types of downhole tools, such as bridge plugs, packers or other sealing
devices, may
incorporate slips 104 having internal buttons.
[0050] Referring now to FIGURE 2, a slip loading 200 with an internal
button 222 is shown
as a cross-sectional schematic diagram. FIGURE 2 is a schematic diagram for
descriptive purposes
and is not drawn to scale or perspective. In FIGURE 2, the operation of slip
104 being forced
against cone 106 in direction given by arrow 120 is illustrated at one side of
a casing 230. As a
result, as the slips move in direction 120, cone 106 engages slip 104 with
appreciable force and
causes slip 104 to be forced towards casing 230 in direction 220. At an outer
surface of slip 104,
an external button 110 may be used to improve engagement of slip 104 with
casing 230, such as
by increasing friction or by mechanical deformation (not shown) of casing 230.
Thus, as cone 106
is engaged when frac plug 100 is set, a cone surface 106-1 may engage with an
angled surface
104-1 of slip 104, which applies force to slip 104 in direction 220.
[0051] Also shown in FIGURE 2 is internal button 222, located at angled
surface 104-1 of slip
104. Angled surface 104-1 may represent an internal or inner surface of slip
104. In particular,
angled surface 104-1 may be parallel to cone surface 106-1 that is designed to
engage slip 104 at
angled surface 104-1. It is noted that an angle of angled surface 104-1 may
correspond to a cone
angle y shown in FIGURE 2. In particular, internal button 222 is visible in a
location at angled
surface 104-1 for engagement by cone surface 106-1. Accordingly, internal
button 222 may
improve the setting force that is applied to slip 104, such as by increasing
friction between slip 104
and cone 106. Because internal button 222 may be formed from a material that
has a higher
coefficient of friction than angled surface 104-1 when in contact with setting
cone 106, such as a
hard metal, a ceramic, a glass, a composite of non-metallic and metallic
materials, or another
composite material (such as a fiber-reinforced ceramic), among others,
internal button 222 may
enable an improved setting of the downhole tool or assembly, and may improve
stability in
operation, because of the increased frictional force that results from
internal button 222. As a
result of this increased frictional force enabled by internal button 222 at
angled surface 104-1, the
ability of slip 104 to hold the downhole tool or assembly in place in
operation may be improved,
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including the ability to stay in place at higher pressures or at higher
flowrates in the wellbore. For
example, the downhole tool or assembly may be enabled to withstand high
pressure, such as
pressures of up to 8 kpsi (about 55 MPa), up to 10 kpsi (about 69 MPa), or up
to 12 kpsi (about 83
MPa) within the wellbore. Furthermore, the downhole tool or assembly may be
enabled to
withstand high flow rates during production, such as such as up to 80 million
standard cubic feet
per day (MMSCFD) of gas or up to 4,000 barrels of oil per day (BOPD).
[0052] In some instances, internal button 222 may accordingly enable a more
compact design
in a given downhole tool or assembly, such as by enabling the use of a single
set of cone 106/slips
104 instead of a plurality of sets, for example, to achieve the same downhole
slip performance (see
also FIGURES 4A and 4B).
[0053] As shown, external buttons 110 and internal button 222 may be formed
as cylindrically
shaped parts that are mounted in corresponding holes formed in slip 104.
Additionally, the
exposed surfaces of external buttons 110 or internal button 222 or both may be
non-parallel with
their respective engaging surfaces, such that external buttons 110 or internal
button 222 have an
edge that can bite in the respective engaging surface when set to further
increase frictional force.
It is noted that in various embodiments, internal button 222 may cause at
least some plastic
deformation in cone 106 when set, such as an indentation that corresponds to
the shape of internal
button 222 and helps to hold internal button 222, and also slip 104, in place
when set. In some
embodiments, cone 106 may be formed from a metal, such as steel, while
internal button 222 may
be formed from a hard material, such as a ceramic. It is noted that a body of
slip 104 may be
formed from any of various materials, including metals or rubbers, resin,
epoxy, or other polymers.
In particular, the body of slip 104 may be a composite material having a
matrix phase as noted
with an inclusion phase that may include various inclusions, such as fibers,
filaments, and particles,
or various combinations thereof.
[0054] In certain embodiments, slip 104 may be made using a filament-
reinforced composite
material, such as an epoxy with glass fiber filaments, among other types of
composite matrix and
inclusion combinations. In particular embodiments, the glass fiber is wound as
a continuous
filament on a mandrel from which individual parts for slip 104 may be cut. One
example of a
filament-reinforced slip part is disclosed in U.S. Patent Application Number
15/981,592 titled
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"Filament Reinforced Composite Material with Load-Aligned Filament Windings"
filed on May
16, 2018, which is hereby incorporated by reference.
[0055] Referring now to FIGURE 3, a flow chart of selected elements of an
embodiment of a
method 300 of using a slip with internal buttons, as disclosed herein. It is
noted that certain
operations described in method 300 may be optional or may be rearranged in
different
embodiments. In various embodiments, method 300 may be performed for various
types of
downhole tools, as described herein.
[0056] Method 300 may begin at step 302 by running a downhole tool to a
depth in a wellbore,
where the downhole tool comprises a setting cone enabled to engage a plurality
of slips located
circumferentially about the setting cone when the downhole tool is set. At
step 304, the downhole
tool is set in the wellbore, including causing the plurality of slips to
engage the setting cone, and
where at least one of the slips is an inner button slip. At step 306, the
plurality of slips are forced
against the setting cone, including the at least one inner button slip, where
the inner button contacts
the setting cone as the outer surface of the plurality of slips engages the
wellbore.
[0057] Referring now to FIGURES 4A and 4B, a frac plug 400 having slips 404
is depicted in
an external view and a sectional view, respectively. FIGURES 4A and 4B are
schematic diagrams
for descriptive purposes and are not drawn to scale or perspective. In FIGURE
4A, frac plug 400
is shown as a compact tool exhibiting a relatively low ratio of tool length to
tool diameter and
includes a frustoconical member 406, which may be similar to or analogous to
cone 106 described
above with respect to FIGURES 1 and 2. Although frustoconical member 406 is
depicted in the
drawings having relatively smooth surfaces, it is noted that in different
embodiments, different
surface roughness, surface geometries, or surface texture may be used, such as
in conjunction with
a given design or material choice of slips 404, for example. Frac plug 400 may
operate to plug a
wellbore, such as a cased wellbore having a casing diameter of 3.5 inches, 4
inches, 4.5 inches, or
5.5 inches, among other casing diameters. Frac plug 400 may be set in place by
compressing frac
plug 400, such that slips 404 are engaged to firmly hold frac plug 400 in a
particular location in a
corresponding wellbore, such as within a casing of the wellbore. Frac plug 400
may be compressed
for setting in place by forcing slips 404 against frustoconical member 406 in
a direction given by
arrow 420. The frictional force of slips 404 pressing against the interior
surface of the wellbore
(or the casing) holds frac plug 400 in place in the set or "plugged"
condition. Accordingly, the
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force that maintains frac plug 400 in the set or plugged condition is achieved
by virtue of the
material strength of slips 404, as well as the friction between slips 404 and
frustoconical member
406. Also visible in FIGURES 4A and 4B are external buttons 410, which are
enabled to engage
the casing when frac plug 400 is set.
[0058] In FIGURE 4A, a sectional line on frac plug 400-1 indicates a
sectional view 400-2
shown in FIGURE 4B. In FIGURE 4B showing the sectional view 400-2, internal
(or inner)
buttons 422 and external buttons 410 are visible. Specifically, internal
buttons 422 are shown
embedded within slip 404 and protrude from slip 404. Also visible in FIGURE 4B
is a slight non-
parallel surface of internal buttons 422, resulting in an edge to
cylindrically shaped internal buttons
422 that is enabled to engage with frustoconical member 406 when frac plug 400
is set (not shown),
such as by biting into or otherwise deforming at least a portion of
frustoconical member 406.
[0059] The non-parallel surface of internal buttons 422 or external buttons
410 may be realized
using different methods. As shown in FIGURE 4B, internal buttons 422 are
regular cylinders that
are embedded in a hole that is drilled at a non-perpendicular angle to an
inner surface 404-1 of slip
404 (see also inner surface 104-1 in FIGURE 1). In other embodiments, internal
buttons 422 or
external buttons 410 may be cylindrical parts that are cut obliquely with a
non-perpendicular
surface at least one end, while the holes drilled in slip 404 are drilled
perpendicular to inner surface
404-1. It is noted that in certain implementations, external buttons 422 or
internal buttons 410
may be non-cylindrical in shape, such as having shapes of triangular prisms,
square prisms,
rectangular prisms, or other polygonal prisms (not shown).
[0060] In this manner, internal buttons 422 may increase the frictional
force by which slip 404
is held in place by frustoconical member 406 when frac plug 400 is set, which
may enable the
relatively low ratio of tool length to tool diameter, such as by allowing frac
plug 400 to have a
single frustoconical member 406, instead of a plurality of cones and a
respective plurality of sets
of slips.
[0061] The above disclosed subject matter is to be considered illustrative,
and not restrictive,
and the appended claims are intended to include all such modifications,
enhancements, and other
embodiments thereof which fall within the true spirit and scope of the present
disclosure.
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