Note: Descriptions are shown in the official language in which they were submitted.
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ANCHOR MECHANISM
100011 This application is related to U.S. Patent Application Serial No.
16/589,496, filed October
1, 2019, now Patent No. 11,111,737, issued September 7, 2021, and U.S. Patent
Application Serial
No. 17/466,530, filed September 3, 2021, the entireties of which are
incorporated by reference
herein.
FIELD OF THE INVENTION
100021 Embodiments of the present invention generally relate to a downhole
anchor mechanism
for a tubular assembly for use in oil and gas wells.
BACKGROUND OF THE INVENTION
100031 Hydraulic fracturing, or fracking, is a technique for cracking rock by
injecting a mixture of
sand and fluid under pressure. This technique enables the extraction of oil or
gas contained in
highly compact and impermeable rocks.
100041 The wellbores for fracking are drilled to a depth at which rock layers
with hydrocarbon
deposits are found. The wellbores are then drilled horizontally along the rock
layer. Hydraulic
fracturing of the horizontal wellbores is usually conducted in multiple
stages, with fractures
created in the surrounding rock at specific points along the wellbore.
100051 Two methods of hydraulic fracturing are most commonly used. One of the
most common
techniques requires the well to have a cemented casing and involves a plug and
perforate technique
whereby cement plugs are created to isolate specific sections within the well;
each section is then
perforated and fractured. The plugs are then drilled, and the production stage
of the operation is
begun.
100061 Another common technique uses a non-cemented casing arrangement where
sliding sleeves
and packers are provided around the outer circumference of the casing string.
Once the casing
string is inserted into the well, the packers are expanded to secure the
string in position and isolate
sections of the well to be fracked. The sleeves are then shifted to an open
position by pumping
specifically sized balls into the well. When a sleeve is actuated under the
action of a ball, fracturing
ports are opened, and the isolated zone is fractured and stimulated by fluid
diverted through the
open fracturing ports. The production stage of the operation can then begin.
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[0007] After a few years in operation, the gas or oil production level of a
well may decrease.
Following the initial production period, it is common to stimulate the well by
refracturing.
Refracturing aims to either increase the original fractures' depth or develop
a new network of
fractures from which gas or oil may be extracted from the rock. Refracturing
often restores well
productivity to close to original levels and thus extends the lifespan of the
well. Refracturing is
performed in an existing wellbore and is, thus, advantageous because it does
not require the steps
of drilling and completing a wellbore. The process of refracturing an existing
well is, therefore,
often significantly less costly and more economical than drilling a new well.
[0008] In wells with a cemented casing, refracturing can be performed by
installing and cementing
a new casing having a smaller diameter than the original casing before a "plug
and perforation"
method of fracturing is used. It is important that the cement layer between
the two casings provides
a high-quality seal for the process to be effective. In addition, the
perforating step conducted during
the refracturing process must go through two casing walls. Alternatively, a
new casing or tubular
conduit provided with an expandable metallic tubular sleeve, or packer, may be
provided where
the sleeve is designed to expand within the original casing of the well with a
plug and perforation
technique subsequently employed again.
100091 With each of these refracturing techniques, the newly provided casing
has a reduced
internal diameter compared to the initial internal diameter of the well
casing. Generally, efforts are
made to maximize the diameter of the new casing by reducing tolerances between
the new casing
and the existing casing to as small as possible. This creates a need for thin-
walled packers to
maintain the greatest inner diameter possible while still achieving sufficient
gripping and sealing
capability on the existing casing.
[0010] A limitation on such thin-walled arrangements is found in forming
threaded couplings
between the components. Such couplings are necessary to maintain a seal,
provide sufficient
tensile loading and meet torque ratings. Premium (sealing) threads are not
available in the required
sizes, and the wall is not thick enough to cut a normal ACME or Stub ACME
thread. Additionally,
these screw-threaded couplings do not handle radial loads well.
100111 Gladstone, GB 2,267,217 discloses a connector with a dowel device for
application in
boring holes for mining or exploration. The device of Gladstone features
grooves for interlocking
sections, but the device is not applicable to refracturing. There is a rotary-
drill casing connector
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with interconnecting male and female sleeves incorporating lugs and sockets
around the periphery
to transmit rotary motion and provide segmental abutment faces for supporting
axial compressive
loads. The two sleeves are held together using a flexible multi-stranded steel
wire rope dowel
inserted manually from the outside via an aperture into a circular annular
cavity, half of which is
formed on the inside face of the female sleeve and half-formed on the outer
face of the male sleeve.
The connection is sealed against leakage or ingress of fluids by a pliable
sealing '0' ring contained
in a groove formed in the sleeve such that the seal is compressed when the
parts are connected.
[0012] Reimert, U.S. Pat. No. 4,659,119 discloses a connector assembly,
including a pin connector
for receipt by a box connector. An external surface of the pin features a
helical groove, a generally
complementary internal surface of the box features a helical groove of the
same rotational sense
and pitch. A helical latch coil is carried in one of the grooves, extending
partly out of the groove.
The connectors are latched together by stabbing the pin into the box so that
the latch coil is
ratcheted into place, partly extending into the groove of the connector not
carrying the coil.
Subsequent mutual rotation between the connectors in one rotational sense
tightens the latched
connection, and rotation in the opposite sense releases the latching. The
connector functions
without the need for substantial rotation or torque.
100131 Bauer et al., U.S. Pat. No. 4,697,947 discloses a plug connection for
drilling or boring
tubes, rods, and worms for earth-boring equipment with a male part and a
female part, with a radial
coupling for torque transfer and with an axial coupling having in the overlap
zone of the male and
female parts, and a locking device that can be introduced into an annulus for
transferring axial
forces. The locking device is constructed as a multilink chain that
essentially extends around the
entire annulus and is introduced through the female part into the annulus via
a single opening.
[0014] Lehmann, DE 2310375 discloses a detachable pipe end connection for
locking opposing
pipe ends with different joint designs and engageable gearing featuring a
retractable overrunning
pipe end rotatably fixed and centered, and both of an inserted flexible
locking cord in one of two
mutually opposite half-grooves in a cavity. The entire tube circumference
outside the coupling
region is blocked and secures and features a flexible locking cord. For
insertion or removal of the
flexible locking cord, window-like openings are provided.
100151 It would be desirable to provide a coupling mechanism for securing
tubular sections in a
wellbore over a thin wall. It is also desirable to provide a anchor mechanism
suited for use with
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thin-wall tubing that is configured to increase radial holding force onto a
casing while not
overstressing tool components.
SUMMARY OF THE INVENTION
100161 It is one aspect of embodiments of the present invention to provide a
downhole tool with a
anchor mechanism comprising a plurality of slips positioned about and
operatively engaged to a
portion of the downhole tool's body (often referred to as a "mandrel"). The
plurality of slips are
configured to slide longitudinally along the mandrel (or portion thereof) and
expand, which causes
distal ends of the slips to engage an inner casing surface. The contemplated
downhole tool may be
a packer, liner hanger, or any other similar tool having a downhole coupling
mechanism at its
lower end configured to interconnect to a tubular string located deeper in a
well.
100171 The plurality of slips may be held in place against the mandrel by a
wire and/or may be
prevented from moving by a shear pin(s). These slip retaining devices maintain
the plurality of
slips adjacent to a conical portion of the mandrel while the downhole tool is
lowered into the well,
which is known to those of ordinary skill in the art as the "run in"
configuration. The application
of a longitudinal force onto proximal slider ends will break the wire and/or
shear pin(s), thereby
allowing the distal slider ends to expand outwardly.
100181 The plurality of slips of the contemplated embodiments of the present
invention can be
forced against the casing surface to a great degree, which increases the
anchor mechanism's
holding capability. More specifically, stresses associated with slip loading
are reacted by the walls
of the mandrel in the tangential and radial directions as opposed to only in
the radial direction. One
of ordinary skill in the art will appreciate that this aspect allows for the
often thin-walled mandrel
to be loaded to a greater degree because the radial load component is
decreased dramatically, which
prevents mandrel compression load damage.
100191 In some instances, a wall thickness of the downhole tool before
actuating the slips is less
than or equal to about 5%, 10%, 15%, or 20% of the outer diameter of the
downhole tool before
actuating the slips. A wall thickness of the downhole tool before actuating
the slips may be less
than or equal to about 8%, 10%, 12%, 14%, 16%, 18%, or 20% of the inner
diameter of the
downhole tool before actuating the slips. This aspect provides a thin-wall
tubular connection. In
some instances, the inner diameter at the coupling mechanism is greater than
or equal to about
3.00", 3.20", 3.40", 3.50", 3.60", 3.70", 3.80", 3.90", 4.00", 4.10", 4.20",
4.40", or 4.60", and the
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outer diameter at the coupling mechanism is less than or equal to about 4.00",
4.10", 4.20", 4.40",
4.50", 4.60", 4.70" 4.80", 4.90", 5.00", 5.10", 5.20", or 5.40". In one
embodiment, the inner
diameter at the coupling mechanism is greater than or equal to about 3.8"
(96.52 mm), and the
outer diameter at the coupling mechanism is less than or equal to 47" (119.38
mm). The inner
diameter provides the clearance through the bore of the downhole tool. The
outer diameter
determines the borehole size or installed casing/liner size through which the
downhole tool can be
run-in.
100201 The downhole tool of one embodiment features a ratchet device that
prevents movement
of the slips from the expanded configuration. That is, the contemplated
ratchet device provides a
mechanism that maintains the plurality of slips in the radially extended
position. The downhole
tool also includes a piston lock to prevent movement of the piston until slip
actuation.
100211 The downhole tool may include a morphable element. The morphable
element may be
considered as a packer element. More preferably, the morphable element is a
sleeve arranged on
the tool body, sealed thereto and providing an annular chamber, that when
fluid is introduced to
the chamber, expands the sleeve to seal against a borehole wall or a tubular
in which the packer
element is located.
100221 Thus, it is one aspect of one embodiment of the present invention to
provide an anchor
mechanism configured for use with a downhole tool, comprising: a member
substantially having
a cylindrical or frusto-conical outer profile, which defines a first
volumetric envelope, and a
plurality of longitudinally-disposed channels provided in the outer profile,
the channels having an
interiorly-disposed surface spaced from the outer profile that is bounded by
angled walls extending
from a distal end of the member and terminate before a proximal end of the
member, thereby
defining distal channel openings; and a plurality of slips, wherein each of
the plurality of channels
receives a corresponding slip, each slip having lateral surfaces configured to
operatively engage
onto the angled walls of the channel in which they are located, the slips
further having: a first
position of use wherein distal ends of the slips are located a first distance
from the distal channel
openings, wherein outermost surfaces associated with portions of the slips
engaged within the
channels do not extend beyond the volumetric envelope of the member; and a
second position of
use wherein distal ends of the slips are located a second distance from the
distal channel openings,
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wherein the outermost surfaces associated with the portions of the slips
engaged within the
channels extend beyond the volumetric envelope of the member.
100231 It is still yet another aspect of one embodiment to provide an anchor
mechanism configured
for use with a downhole tool, comprising: a member having an outer profile and
a plurality of
longitudinally-disposed channels provided in the outer profile; and a
plurality of slips, wherein
each of the plurality of channels receives a corresponding slip, the slips
further having. a first
position of use wherein distal ends of the slips are located a first distance
from the distal channel
openings; and a second position of use wherein distal ends of the slips are
located a second
distance from the distal channel openings, and wherein the distal ends of the
slips extend away
from the outer profile.
100241 It is another aspect of one embodiment of the present invention to
provide a downhole
tool, comprising: a mandrel having a proximal end configured to be located
towards an opening
of a well; a cone positioned about the mandrel, the cone having an outer
profile and a plurality of
longitudinally-disposed channels provided in the outer profile; a plurality of
slips positioned about
the mandrel and operatively received by the plurality of channels; a spacer
ring positioned about
the mandrel and associated with distal ends of the slips; and a piston
positioned about the mandrel
and associated with the spacer ring.
100251 The Summary of the Invention is neither intended nor should it be
construed as being
representative of the full extent and scope of the present invention. That is,
these and other aspects
and advantages will be apparent from the disclosure of the invention(s)
described herein. Further,
the above-described embodiments, aspects, objectives, and configurations are
neither complete
nor exhaustive. As will be appreciated, other embodiments of the invention are
possible using,
alone or in combination, one or more of the features set forth above or
described below. Moreover,
references made herein to "the present invention" or aspects thereof should be
understood to mean
certain embodiments of the present invention and should not necessarily be
construed as limiting
all embodiments to a particular description. The present invention is set
forth in various levels of
detail in the Summary of the Invention as well as in the attached drawings and
the Detailed
Description and no limitation as to the scope of the present invention is
intended by either the
inclusion or non-inclusion of elements, components, etc. in this Summary of
the Invention.
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Additional aspects of the present invention will become more readily apparent
from the Detailed
Description, particularly when taken together with the drawings.
[0026] The above-described benefits, embodiments, and/or characterizations are
not necessarily
complete or exhaustive, and in particular, as to the patentable subject matter
disclosed herein.
Other benefits, embodiments, and/or characterizations of the present invention
are possible
utilizing, alone or in combination, as set forth above and/or described in the
accompanying figures
and/or in the description herein below.
[0027] The phrases "at least one," "one or more," and "and/or," as used
herein, are open-ended
expressions that are both conjunctive and disjunctive in operation. For
example, each of the
expressions "at least one of A, B and C," "at least one of A, B, or C," "one
or more of A, B, and
C," "one or more of A, B, or C," and "A, B, and/or C" means A alone, B alone,
C alone, A and B
together, A and C together, B and C together, or A, B and C together.
[0028] Unless otherwise indicated, all numbers expressing quantities,
dimensions, conditions, and
so forth used in the specification and drawing figures are to be understood as
being approximations
which may be modified in all instances as required for a particular
application of the novel
assembly and method described herein.
[0029] The term "a- or "an- entity, as used herein, refers to one or more of
that entity. As such,
the terms "a" (or "an"), "one or more" and "at least one" can be used
interchangeably herein.
[0030] The use of "including," "comprising," or "having" and variations
thereof herein is meant
to encompass the items listed thereafter and equivalents thereof as well as
additional items.
Accordingly, the terms "including," "comprising," or "having" and variations
thereof can be used
interchangeably herein.
[0031] It shall be understood that the term "means" as used herein shall be
given its broadest
possible interpretation in accordance with 35 U.S.C., Section 112(f).
Accordingly, a claim
incorporating the term "means" shall cover all structures, materials, or acts
set forth herein, and all
of the equivalents thereof. Further, the structures, materials, or acts and
the equivalents thereof
shall include all those described in the Summary, Brief Description of the
Drawings, Detailed
Description and in the appended drawing figures.
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BRIEF DESCRIPTION OF THE DRAWINGS
100321 The accompanying drawings, which are incorporated in and constitute a
part of the
specification, illustrate embodiments of the invention and, together with the
general description of
the invention given above and the detailed description of the drawings given
below, serve to
explain the principles of these inventions.
100331 Fig. 1 is a partial perspective view of a downhole coupling mechanism
as described herein.
100341 Fig. 2A is a cross-sectional view through a first tubular section of
the downhole coupling
mechanism of Fig. 1.
100351 Fig. 2B is a cross-sectional view through a second tubular section of
the downhole coupling
mechanism of Fig. 1.
100361 Fig. 3A is a cross-sectional view through an anchor including the
downhole coupling
mechanism of Fig. 1
100371 Fig. 3B is an exploded view of Fig. 3A.
100381 Fig. 4A is a cross-sectional view of the piston of the anchor of Fig. 3
shown in locked
configuration.
100391 Fig. 4B is a cross-sectional view of the piston of the anchor of Fig. 3
shown in an unlocked
configuration.
100401 Fig. 5 is a perspective view of an alternate anchor, including the
coupling mechanism of
Fig. 1.
100411 Fig. 6 is a cross-sectional view through a packer suitable for use with
the downhole
coupling mechanism of Fig. 1.
100421 Fig. 7 is a perspective view of a downhole tool that employs an
alternate anchor
mechanism.
100431 Fig. 8 is an elevation view of Fig. 7.
100441 Fig. 9 is a perspective view of an anchor mechanism of one embodiment
of the present
invention, wherein components have been removed for clarity.
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[0045] Fig. 10 is a front elevation view of Fig. 9.
[0046] Fig. 11 is a partial cross-sectional view showing the anchor mechanism
of Fig. 9.
[0047] Fig. 12 is a cross-sectional view of Fig. 7.
[0048] Fig. 13 is a detailed view of Fig. 12, showing the downhole tool in a
run-in position of use.
[0049] Fig. 14 is a detailed view of Fig. 14, showing the downhole tool in a
set position of use.
[0050] Fig. 15 is a perspective view showing a cone of the anchor mechanism of
Fig. 9.
[0051] Fig. 16 a front cross-sectional view of Fig. 15.
[0052] Fig. 17 is a perspective view showing a cone of Fig. 15 as a material
blank.
[0053] Fig. 18 is a side elevation view of Fig. 17.
[0054] Fig. 19 is a right elevation view of Fig. 17, wherein the blank has
been modified to define
a plurality of fingers with channels therebetween.
[0055] It should be understood that the drawings are not necessarily to scale.
In certain instances,
details that are not necessary for an understanding of the invention or that
render other details
difficult to perceive may have been omitted. It should be understood, of
course, that the invention
is not necessarily limited to the particular embodiments illustrated herein.
DETAILED DESCRIPTION
[0056] Referring to Fig. 1, the drawings illustrate a downhole coupling
mechanism 10 as described
herein. The coupling mechanism 10 features a first tubular section 12 and a
second tubular section
14 connected via a tensile load arrangement 16, a torque arrangement 18 and a
seal arrangement
20. Arrangements 16, 18, 20 allow the tubular sections 12, 14 to be fixed
together without a screw-
threaded connection and can thus find application in small diameter bores and
casing strings used
downhole.
[0057] The first tubular section 12 is considered as an end piece to a
downhole tool 22. The
downhole tool 22 may be an packer, liner hanger, or similar tool used within a
wellbore. Fig. 2A
illustrates a tubular member 24 forming a portion of a downhole tool 22 and
having a first tubular
section 12 at a first end 26 thereof. Tubular section 12 has a smooth
circumferential inner surface
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28. The outer surface 30 is provided with a series of grooves 32. Each groove
32 may be square in
cross-section though may be of any cross-sectional shape such as circular, v-
grooved, dovetailed
or a hooked profile. Each groove 32 is provided into the outer surface 30 to
provide a continuous
groove depth around a circumference of the outer surface 30. There are several
grooves 32. In one
embodiment, there are fifteen grooves, but there may be any number ranging
typically from 3 to
20. The parallel grooves 32 are perpendicular to the bore 34 through the tool
22 and provide a
continuous circumferential profile on the outer surface 30. The shape is
entirely circumferential in
that a cross-sectional view, as shown in Fig. 2A, would be identical for every
cross-section around
the tubular section 12. This is in contrast to a screw thread arrangement that
would provide a single
groove helically wound on the outer surface. A single wire may be fed around
such a helical
groove.
100581 The first tubular section 12 also features lugs 36. Lugs 36 are
protrusions or tongues
extending from the end face 38 of section 12. These are best seen with the aid
of Fig. 1. In one
embodiment, two lugs 36 arranged equidistantly around the end face 38 are
provided. However,
there may be any number of lugs 36. Each lug 36 is may be square in cross-
section with rounded
edges to assist in assembly. Each lug 36 is of the same thickness as the wall
thickness 40 of section
12 so that the inner 28 and outer surfaces 30 extend over the lugs. A
protrusion length 42, coaxial
with the bore 34, is also greater than the wall thickness 40.
100591 Fig. 2B illustrates the second tubular section 14 being the
complementary mating section
to the first tubular section 12. The second tubular section 14 also has a
cylindrical body and a series
of grooves 44. Grooves 44 match the grooves 32 in number, depth, and position
along section 14
but are now arranged on the inner surface 46. A longitudinally arranged access
window 48 is
machined through section 14 over the grooves 44.
100601 Adjacent to the grooves 44 are two further grooves 50a, 50b. The
further grooves 50 a, 50
b are wider and deeper than the grooves 44, but they are also continuous
around the inner surface
46 and are neither helical nor provide a thread. Though two further grooves
50a, 50b are shown,
there may be a single further groove or more than two further grooves, but
there will always be
fewer further grooves 50 than grooves 44.
100611 When considered from an end face 52 of the second tubular section 14,
there are the
grooves 44, the further grooves 50 and then a stop edge 54. Stop edge 54 is
provided by a reduction
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in the inner diameter of the tubular section 14, providing a circumferential
rim or lip arranged
perpendicular to the bore 56. The stop edge 54 has a width greater than or
equal to the wall
thickness 40 of the first tubular section 12. Machined into the stop edge 54
is a notch 58 that does
not extend through the wall thickness. There are two notches 58 that may be
equidistantly
machined around the edge 54; the number and dimensions of each notch 58 match
the lugs 36 on
the first tubular section 12. The second tubular section 14 may form part of
tubing such as casing
or liner. The second tubular section 14 may be considered as a bottom sub for
connection to other
downhole tools and components.
100621 Returning to Fig. 1, the coupling mechanism 10 is illustrated in an
assembled form. The
second tubular section 14 has been slid over the first tubular section 12
until the end face 38 has
abutted the stop edge 54. The sections 12 and 14 have been aligned so that the
lugs 36 fit in the
notches 58. Before engagement, seals 60 a, 60 b have been located in the
further grooves 50 a, 50
b. Upon engagement, grooves 44 will be coaxial with grooves 32. Separate wires
62 are each
located in one of the groove pairs 32,44 and joined to provide individual wire
loops in each groove
44 via the access window 48.
100631 The grooves 32,44 with corresponding wires 62 provide the tensile load
arrangement 16.
In one embodiment, there are fifteen grooves 32, 44 with corresponding wires
62. However, there
may be more than three wires. There may be more than eleven wires. The
increased number of
wires increases the tensile loading of the coupling 10. The wires 62 may be of
square cross-section
and may be considered as a square locking wire. Wire having circular,
triangular, rectangular, or
other cross-sections may also be used. Each wire 62 has a diameter in cross-
section, perpendicular
to the axis of the bores 34, 56, greater than a depth of a groove 32, 44 into
which they locate. This
ensures that the wires 62 lie between the first and second tubular sections
12, 14. In the
embodiment shown, the wires 62 are sized to fill both grooves 32,44 to prevent
relative
longitudinal movement of the tubular sections 12,14. This provides the
required tensile loading
through the coupling mechanism 10.
100641 The seals 60a, 60b, within the further grooves 50a, 50b, that are sized
to protrude from the
further grooves 50a, 50b and be compressed against the outer surface 30 of the
first tubular section
12 provides the seal arrangement 20. The seal arrangement 20 prevents the
egress of fluid through
the coupling mechanism 10.
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100651 The combination of the lugs 36 and notches 58 provide the torque
arrangement 18. The
length 42 of the lugs 36 provides abutting surfaces between the lugs 36 and
notches 58 that are
parallel with the axis of the bores 34, 56. As this length 42 is greater than
a wall thickness 64 of
the coupling mechanism 10, this gives a torque rating to the coupling
mechanism 10 greater than
the torque rating of a screw-threaded connection of similar thickness.
100661 The tensile load arrangement 16, torque arrangement 18 and seal
arrangement 20 of the
coupling mechanism 10 can all be formed over relatively small wall
thicknesses. The coupling
mechanism 10 is suitable for slim hole arrangements where a maximum bore 34,
56 is required to
be maintained. The wall thickness 64 of the made-up coupling mechanism 10 is
less than or equal
to 10% of the outer diameter 66 of the coupling mechanism 10. Also, the wall
thickness 64 is less
than or equal to 12% of the inner diameter 68 of the coupling mechanism 10.
This provides a thin-
wall tubular connection. In one embodiment, the inner diameter 68 is greater
than or equal to
3.843" (97.61 mm) and the outer diameter 66 is less than or equal to 4.700"
(118.44 mm). The
inner diameter 68 provides clearance through the bore 34, 56 of the downhole
tool 22.
100671 By providing such a small relative wall thickness over the tubing
diameter, the coupling
mechanism 10 finds use on downhole tools used in refracturing operations such
as anchors, liner
hangers, and packers and provides particular advantages. An embodiment of a
suitable anchor 70
with the coupling mechanism 10 is now described with reference to Figs. 3A,
3B, 4A, and 4B.
100681 Fig. 3A is a cross-section view of a downhole tool 22 being an anchor
70 incorporating the
coupling mechanism 10 according to an embodiment described herein. The figure
is provided in
the standard downhole format with the right side being the lower end 72 of the
tool 22 that is run
into the wellbore first before the upper end 74 of the tool 22 shown on the
left side of the figure.
Fig. 3B is an exploded view of a section of the anchor 70 of Fig. 3A so that
the features are clearer.
100691 Anchor 70 features a substantially tubular body 76 with a maximum outer
diameter 78 and
minimum inner diameter 80. At the lower end 72 a coupling mechanism 10 is
provided as
described herein for connecting the anchor to another downhole component (not
shown). The first
tubular section 12 is part of an inner mandrel 82 that is connected at the
upper end 74 to a J-housing
84 as is known in the art.
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100701 At the upper end 74 of the inner mandrel 82, the diameter is tapered to
provide a downward-
facing wedge 86 around the mandrel 82. Slips 88 are arranged around the
mandrel 82 and initially
held in place using a retaining wire 90 wrapped around the outside of the
slips 88. Using a retaining
ring 90 advantageously removes the requirement for mounts for the slips 88
that would increase
the wall thickness 79 of the tool 22. The slips 88 abut a spacer ring 92 that
can be moved upwards
by action of a piston 102 so as to force the slips 88 up the wedge 86 moving
them radially outwards
to contact an inner surface 94 of the outer tubing 96. Movement of the slips
is initially prevented
by the location of a shear pin 98 in the wedge 86 at the front of the slips
88. This arrangement
provides anchoring of the downhole tool 22 to the outer tubing 96.
100711 A piston locking assembly 100 is used to prevent premature actuation of
the anchor 70,
especially during run-in. The piston locking assembly 100 sits between the
spacer ring 92 and the
coupling mechanism 10. Fig. 4A shows the piston locking assembly 100 in a run-
in configuration.
100721 Piston locking assembly 100 includes the piston 102 being a cylindrical
body arranged
around the mandrel 82. At the upper end, it is connected to the spacer ring 92
via a wire and groove
arrangement as per the tensile load arrangement 16 described hereinbefore.
Four wires are
illustrated, but there could be any number. Behind the spacer ring 92 is a
locking ring 104 whose
outer surface 106 is threaded to attach to an inner surface 108 of the piston
102. The inner surface
110 of the locking ring 104 is also threaded with a complementary left-hand
thread 112 along the
outer surface 114 of the mandrel 82 that extends to the wedge 86. At a lower
end of the piston 102
are collet fingers 116 directed inwardly and located in a recess 118 formed on
the outer surface
114 of the mandrel 82. Recess 118 is located below a port 120 through the
mandrel 82.
100731 Below the piston 102 is a locking element 122. The ring has an upwardly
directed lip 124
at its upper end, extending the outer surface 126 at the upper end. The
locking element 122 also
has a circumferential groove 134 around the outer surface 126 towards a lower
end. A piston
housing 128 slides over the locking element 122 and a portion of the piston
102. The piston housing
128 is fixed to the inner mandrel 82 and/or a second tubular portion 14 at the
lower end. The
locking element 122 is moveable between the housing 128 and mandrel 82 but is
sealed 130 to
both and initially held in place via a shear pins 132 through the housing 128
locating in the groove
134. Similarly, the piston 102 is moveable between the housing 128 and mandrel
82 but is sealed
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136 to both and initially held in place by virtue of the collet fingers 116
located in the recess 118
and locked in place by the lip 124 of the locking element 122.
100741 In the run-in configuration, shown in Figs. 3A, 3B, and 4A, the slips
88 are held in position
at the bottom of the wedge 86 by the retaining wire 90. The spacer ring 92
abuts the slips 88 and
is held to the piston 102 with the locking ring 104 sitting adjacent the
spacer ring 92 and connecting
to the mandrel 82 and piston 102. The collet fingers 116 and in the recess
118. The locking element
122 is positioned so that the lip 124 is over ends of the collet fingers 116
and supports them in the
recess 118. The locking element 122 is prevented from moving off the fingers
116 as it is held in
place by shear pin 132 located through the housing 128 and locating in the
groove 134. In this
configuration, the tool 22 can be run in the outer tubing 96, and if it
encounters ledges such as at
casing collars, it cannot be activated.
100751 When the anchor 70 requires setting, pressure is applied through the
bore 138 from the
surface. The pressurized fluid enters the tool 22 through the port 120. The
pressure acts on the
locking element 122 until the pressure is sufficient to shear the pins 132
allowing the element to
move downward until the lip 124 is clear of the collet fingers 116. This
releases the collet fingers
116 so that they come out of the recess 118. Fluid pressure now acts on the
piston 102 moving it
upwards. The piston 102 acts on the locking ring 104, spacer ring 92 and
ultimately the slips 88.
With sufficient pressure the slips 88 move upwards along the wedge 86 and
radially outwards so
that they contact and grip the inner surface 94 of the outer tubing 96. On
movement the slips 88
will contact and shear the shear pins 98 while breaking the retaining wire 90.
Due to the close
tolerance between the slips 88 and the outer tubing 96, the slips 88 will
never clear the width of
the spacer ring 92 and thus will only move upwards and outwards. The anchor
set arrangement is
illustrated in Fig. 4B. Advantageously, pressure does not have to be held to
keep the anchor in the
set configuration due to the locking ring 104 arrangement on the mandrel 82
that acts as a ratchet
when the piston 102 moves.
100761 The overall outer diameter 78 of the anchor 70 in the run-in
configuration is less than or
equal to the overall outer diameter 66 of the coupling mechanism 10. Thus, the
anchor 70 is
suitable for slim hole applications. Additionally, the minimum inner diameter
80 of the anchor 70
is equal to the minimum inner diameter 68 of coupling mechanism 10 by virtue
of the inner tubular
section 12 of the coupling mechanism 10 being formed on the same mandrel 82 as
the anchor 70.
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Thus, the wall thickness 64, 79 of the anchor 70 and coupling mechanism 10 are
substantially the
same.
100771 Fig. 5 illustrates an alternative embodiment for the slips 88A that
provides a mechanical
constraint to prevent the slips 88A from unwanted movement until actuation.
Those like parts to
FIGS. 3 and 4 are given the same reference numbers and suffixed 'A,' for
clarity. Fig. 5 shows an
anchor 70A where at the lower end 72A there is arranged a coupling mechanism
10A as described
herein for connecting the anchor to another downhole component (not shown).
[0078] At the upper end 74A of the inner mandrel 82A, the diameter is tapered
to provide a
downward facing wedge 86A around the mandrel 82A. Slips 88A are arranged
around the mandrel
82A and initially held in place using three retaining wires 90A wrapped around
the outside of the
slips 88A in the same manner as for FIGS 3 and 4 However, where the slips 88
abutted a spacer
ring 92 in the earlier embodiment, the slips 88A now have tabs 91 extending
from a lower end 93.
Typically, there is a tab 91 on each section of the slip 88A. Spacer ring 92A
is extended to provide
mating recesses 95 for the tabs 91. The spacer ring 92A is connected to the
piston 102A in an
identical manner as before with the addition of a securing band 97, between a
lower shoulder 99
of the spacer ring 92A and the end face 101 of the piston 102. The securing
band 97 (shown in
transparency in Fig. 6) of soft metal lies over the interlocking arrangement
of tabs 91 and recesses
95 to prevent movement radially outwards when the piston 102 is actuated.
Further, the shear pin
88 on the wedge 86 is now a pin or screw 88A, located in a front tab 103 of
each slip 88A. This
secures the front or nose of the slips 88A to the mandrel 82A to provide added
security to the slips
and prevent unwanted movement until actuation is desired. Anchor 70A is
operated in the same
manner as anchor 70.
[0079] A further embodiment of a downhole tool 22 that can use the coupling
mechanism 10 is a
packer 140, as illustrated in Fig. 6. Packer 140 features three tubular parts,
a mandrel 142, a bottom
section 144, and a sleeve member 146. Each part is machined as a single piece,
and the bottom
section 144 forms the first tubular section 12 of the coupling mechanism 10.
The mandrel 142
provides a downward facing ledge 148 perpendicular to an axis of the central
bore 150 on its outer
surface 152. There is a port 154 through the mandrel 142. The mandrel 142 has
an end face 156 at
its lower end that is perpendicular to the axis of the central bore 150. The
bottom section 144 is
arranged at the lower end of the mandrel with a portion 158 extending over the
mandrel 142 and
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presenting an upward facing end face 160 that is perpendicular to the axis of
the central bore 150.
The bottom section 144 has an upward facing ledge 162 that is perpendicular to
the axis of the
central bore 150. The lower end of the bottom section 144 forms the first
tubular section 12 of the
coupling mechanism 10. A tubular section with first and second end faces 164,
166 respectively
forms the sleeve member 146.
100801 The sleeve member 146 is slid over the mandrel 142 in order to abut the
ledge 148 with the
first end face 164. 'The ledge 148 and face 164 are joined together. The
bottom section 144 is then
slid over the end of the mandrel 142 so the portion 158 sits on the mandrel
and the end face 160
abuts the second end face 166 of the sleeve member 146. The faces are joined
together. This
connection also sees the ledge 162 of the bottom section 144 abutting the end
face 156 of the
mandrel 142. The ledge 162 and face 156 are joined together. The mandrel 142
and bottom section
144 are made of a hardened steel that does not yield under pressure. The
sleeve member 146 is
made of a ductile metal that yields under pressure. The joints are formed by
welding or other
suitable techniques known to those skilled in the art to provide a pressure
tight seal between the
components.
100811 The packer 140 is run into the well in the configuration shown in Fig.
6. At the desired
location, fluid pressure is increased from the surface, or via a running tool
inside the packer 140,
so that fluid under pressure enters the port 154. This fluid reaches a chamber
168 created between
the outer surface 152 of the mandrel 142 and the inner surface 170 of the
sleeve member 146. The
ductile metal of the sleeve member 146 yields and expands. The sleeve member
146 morphs
against the inner surface 94 of the outer tubing 96 and creates a metal to
metal seal. As the sleeve
member 146 undergoes elastic and plastic deformation during morphing, the
packer 140 holds a
seal between the packer 140 and the outer tubing 96 thereby maintaining a seal
across the annulus
between both.
100821 The overall outer diameter 172 of the packer 140 in the run-in
configuration is less than or
equal to the overall outer diameter 66 of the coupling mechanism 10. Thus, the
packer 140 is
suitable for slim hole applications. Additionally, the minimum inner diameter
174 of the packer
140 is equal to the minimum inner diameter 68 of the coupling mechanism 10 by
virtue of the
inner tubular section 12 of the coupling mechanism 10 being formed in the same
piece as the
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bottom section 144. Thus, the wall thickness 64, 176 of packer 140 and
coupling mechanism 10
are substantially the same.
100831 The anchor 70 may be used along with the packer 140 on a string.
Advantageously the
anchor 70 may be located above the packer 140 as the anchor 70 does not
require holding pressure
in use. This is the reverse of typical packers where the slips are used to
expand the packer element
and thus pressure must be held by the anchor to keep the packer element
expanded in use.
100841 Figs. 7, 8, and 12-14 show a downhole tool 322 of another embodiment of
the present
invention that employs an alternative anchor mechanism 370. The downhole tool
322 generally
consists of a mandrel 382 interconnected to a cone 500 that selectively
receives a plurality of slips
388. The slips are associated with a piston 402, which is also operatively
interconnected to a
housing 428 Figs 7, 8, and 12-14 are provided in the standard downhole format,
with the right
side being a lower end 372 of the tool 322 that is run into the wellbore
before an upper end 374 of
the tool 322.
100851 The downhole tool 322 has a maximum outer diameter and minimum inner
diameter. The
lower end 372 is configured to selectively accept another downhole component
(not shown) using
a coupling mechanism 310. The contemplated coupling mechanism may be that
shown in Figs. 1-
2B, wherein a first tubular section 12 is part of the mandrel 382, as is known
in the art.
100861 Figs. 9-11 show the anchor mechanism 370 employed by this embodiment of
the present
invention that comprises a cone 500 configured to interconnect to the mandrel
and a plurality of
operatively interconnected slips 388. The slips 388 are arranged around the
cone 500 and may be
initially held in place using a retaining wire positioned in a groove 532
provided in the slips 388.
The retaining wire removes the requirement for slip mounts that would increase
the tool's wall
thickness. The slips 388 are secured to the tool body by a slip retainer ring
504 that maintains the
slip proximal ends 508 against the mandrel. Movement of the slips may also be
initially prevented
by a shear pin(s) located in webbing 516 of the cone 500 that abuts the distal
slip ends 512.
100871 The slips 388 abut a spacer ring (Fig. 13, 392) that is moved by a
piston 402 to force the
slips 388 further onto the cone 500. The cone 500 includes a plurality of
longitudinal channels
configured to receive corresponding slips. The channels have interior surfaces
that define the
webbing 516 and angled or faceted lateral surfaces 524 that function somewhat
like the wedge
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described above. The channels of one embodiment of the present invention are
tapered and wider
at the distal end of the cone 500. The slips 388 may be likewise tapered,
wherein the proximal ends
thereof are wider than the distal ends. In operation, as the slips move in the
direction of Arrow A,
which will be described in further detail below, the slip distal ends 512 will
engage lateral surfaces
520, which urge the slips outwardly, generally along the path of Arrow B (see
Fig. 14). Movement
of the slips 388 within channels engages slip lateral surfaces 520 onto
corresponding channel walls
524. As will be more apparent upon review of Figs. 15 and 16, the channels
also define fingers
528 that maintain the slip's 388 angular orientation relative to the cone's
outer diameter.
100881 Figs. 12-14 illustrate the operation of the anchor mechanism 370 of one
embodiment of the
present invention that employs a piston locking assembly 400 to prevent
premature actuation of
the anchor 370 during run-in. The piston locking assembly 400 is located
between the spacer ring
392 and the coupling mechanism 310. Figs. 12 and 13 show the piston locking
assembly 400 in a
run-in configuration. The piston 402 is a cylindrical body arranged around the
mandrel 382 and is
connected at its upper end to the spacer ring 392 via a wire and groove
arrangement, which may
be similar to the configuration described above. A locking ring 404 is
positioned behind the spacer
ring 392. The locking ring 404 has an outer threaded surface 406 that attaches
to an inner surface
408 of the piston 402. Collet fingers 416 are located at a lower end of the
piston 402. The collet
fingers are directed inwardly and locate in a recess 418 formed on the outer
surface 414 of the
mandrel 382. The recess 418 is located below a port through the mandrel 382
(see Fig. 12,
reference numeral 420).
100891 A piston lock 422 is positioned below the piston 402 and generally
comprises a ring with
a lip 424 at its upper end. The piston lock 422 also has a circumferential
groove 434 around the
outer surface adjacent to its lower end. A piston housing 428 slides over the
locking element 422
and a portion of the piston 402. The piston housing 428 is fixed to the
mandrel 382 and/or a second
tubular portion 314 at the lower end. The locking element 422 is moveable
between the housing
428 and mandrel 382 but is sealed to both and initially held in place via a
shear pins/screws 432
through the housing 428 located in the groove 434. Similarly, the piston 402
is moveable between
the housing 428 and mandrel 382 but is sealed to both and initially held in
place by the collet
fingers 416 located in the recess 418 and locked in place by the lip 424 of
the locking element 422.
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100901 In the run-in configuration, shown in Figs. 12 and 13, the slips 388
are held in position at
the bottom of the cone 500 by the retaining wire. The spacer ring 392 abuts
the proximal end of
the slips 388 and is held to the piston 402 with the locking ring 404
positioned adjacent the spacer
ring 392 and connecting to the mandrel 382 and piston 402. The collet fingers
416 are shown in
the recess 4118, and the locking element 422 is positioned so that the lip 424
is located over the
ends of the collet fingers 416 to maintain the collet fingers in the recess
418. The locking element
422 is prevented from moving from the fingers 416 as it is held in place by
the shear pin 432
located through the housing 428 and located in the groove 434. In this
configuration, the tool 322
can be run into the casing 96, and if it encounters ledges such as at casing
collars, it cannot be
activated.
100911 The anchor mechanism set arrangement is illustrated in Fig. 14.
Pressurized fluid enters
the tool 322 through the bore 438 which exits the port 420 to "set" the anchor
mechanism 370.
The pressurized fluid acts on the locking element 422 until the pressure is
sufficient to shear the
pins 432, allowing the locking element 422 to move downward until the lip 424
clears the collet
fingers 416, which allows the collet fingers 416 to expand out of the recess
418. Fluid pressure
then acts on the piston 402, moving it upwards to act on the locking ring 404,
spacer ring 392, and
ultimately the slips 388. The slips 388 will move upwards along the cone 500
and radially outwards
until they contact and grip the inner surface of the casing 96, wherein teeth
550 of the slips dig
into the casing. Urging the slips in this matter will also abut the slip
distal ends against
corresponding shear pins to sever the same and break any retaining wires
provided. Close
tolerance between the slips 388 and the casing 96 prevents the slips 388 from
clearing the outer
diameter of the spacer ring 392 and, thus, movement of the slips in the
direction opposite Arrow
A is impossible. In one embodiment, pressure does not have to be held to keep
the anchor
mechanism in the set configuration due to the locking ring 404 arrangement on
the mandrel 382
that acts as a ratchet preventing the piston from traveling in a direction
opposite Arrow A.
100921 The overall outer diameter of the downhole tool in the run-in
configuration is less than or
equal to the overall outer diameter of the coupling mechanism. Thus, the
anchor mechanism 370
is suitable for slim hole applications. Additionally, in some embodiments, the
minimum inner
diameter of the anchor mechanism 370 is equal to the minimum inner diameter of
the coupling
mechanism by virtue of the inner tubular section of the coupling mechanism
being formed on the
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same mandrel 382 as the anchor mechanism 370. Thus, the wall thickness of the
anchor mechanism
and the coupling mechanism may be substantially the same.
[0093] Figs. 15 and 16 show the cone 500 of one embodiment of the present
invention. As
described above, the cone 500 is generally comprised of a series of
circumferentially situated
fingers 528 that define channels therebetween. The channels are further
defined by a bottom
surface that comprises the aforementioned webbing 516 bounded by angled or
faceted lateral walls
524. In operation, the lateral walls 524 are loaded in the tangential
direction when engaged by
corresponding slip lateral surfaces 520 as the slips move in the direction of
Arrow A. The
tangential loads, which is denoted as FT, generally compress the fingers 528.
As in the
embodiments described above, the slips will eventually engage the casing,
wherein a reactive
radial load will be directed into the outer surfaces of the slips which will
transfer to zones where
the slip lateral surfaces 520 and the channel walls 524 engage. Because the
engagement surfaces
are angled relative to the radial direction, the reactive load will be split
into a X-Y components,
depicted in the drawings as FR and FT. One of ordinary skill in the art will
appreciate FR is akin to
a reduced radial load and FT is a tangential load directed into the thickness
of the fingers and
compresses the same. One of ordinary skill in the art will appreciate that
this configuration, thus,
creates force components in directions other than radially into the mandrel
end, i.e. the cone, as in
the embodiments described above. Accordingly, the cone 500 can receive much
more slip loading,
which translates into a more secure grasp of the tool onto the casing.
[0094] It will also be appreciated from a review of Figs. 15 and 16 that a
fluid flow path associated
with the outer surface of the fingers will be provided when the slips are
engaged onto the casing
wall, which may be beneficial.
[0095] Fig. 17-19 illustrate the construction of an cone 500 of one embodiment
of the present
invention; those of ordinary skill in the art will appreciate that the
dimensions shown are for
reference only and only illustrate the dimensions used in one embodiment of
the present invention.
Indeed, the magnitudes of FR and F r are directly proportional to the channel
wall angle, which will,
thus, dictate the cone wall thickness needed to withstand a given load.
[0096] Exemplary characteristics of embodiments of the present invention have
been described.
However, to avoid unnecessarily obscuring embodiments of the present
invention, the preceding
description may omit several known apparatus, methods, systems, structures,
and/or devices one
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of ordinary skill in the art would understand are commonly included with the
embodiments of the
present invention. Such omissions are not to be construed as a limitation of
the scope of the claimed
invention. Specific details are set forth to provide an understanding of some
embodiments of the
present invention. It should, however, be appreciated that embodiments of the
present invention
may be practiced in a variety of ways beyond the specific detail set forth
herein.
100971 Modifications and alterations of the various embodiments of the present
invention
described herein will occur to those skilled in the art. It is to be expressly
understood that such
modifications and alterations are within the scope and spirit of the present
invention, as set forth
in the following claims. Further, it is to be understood that the invention(s)
described herein is not
limited in its application to the details of construction and the arrangement
of components set forth
in the preceding description or illustrated in the drawings. That is, the
embodiments of the
invention described herein are capable of being practiced or of being carried
out in various ways.
The scope of the various embodiments described herein is indicated by the
following claims rather
than by the foregoing description. And all changes which come within the
meaning and range of
equivalency of the claims are to be embraced within their scope. It is
intended to obtain rights
which include alternative embodiments to the extent permitted, including
alternate,
interchangeable and/or equivalent structures, functions, ranges or steps to
those claimed, whether
or not such alternate, interchangeable and/or equivalent structures,
functions, ranges or steps are
disclosed herein, and without intending to publicly dedicate any patentable
subject matter.
[0098] The foregoing disclosure is not intended to limit the invention to the
form or forms
disclosed herein. In the foregoing Detailed Description, for example, various
features of the
invention are grouped together in one or more embodiments for the purpose of
streamlining the
disclosure. This method of disclosure is not to be interpreted as reflecting
an intention that the
claimed inventions require more features than expressly recited. Rather, as
the following claims
reflect, inventive aspects lie in less than all features of a single foregoing
disclosed embodiment.
Thus, the following claims are hereby incorporated into this Detailed
Description, with each claim
standing on its own as a separate preferred embodiment of the invention.
Further, the embodiments
of the present invention described herein include components, methods,
processes, systems, and/or
apparatus substantially as depicted and described herein, including various
sub-combinations and
subsets thereof Accordingly, one of skill in the art will appreciate that
would be possible to provide
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for some features of the embodiments of the present invention without
providing others. Stated
differently, any one or more of the aspects, features, elements, means, or
embodiments as disclosed
herein may be combined with any one or more other aspects, features, elements,
means, or
embodiments as disclosed herein
22
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