Note: Descriptions are shown in the official language in which they were submitted.
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TITLE: CEMENTING TOOL AND METHOD FOR USING SAME
INVENTOR: Allen RicaIton
TECHNICAL FIELD:
[0001] The present disclosure is related to the field of tools for cementing
in casing in a
well bore, in particular, cementing tools for cementing in casing in wells
that will be
fracturized to stimulate production of hydrocarbons.
BACKGROUND:
[0002] Well bores are often completed by injecting cement around the casing in
the
annulus space surrounding the casing in the well bore. The cement can hold the
casing
in place in the well bore, and can further create isolation in the well bore
by preventing
the passage of fluid between sections or stages within the well bore. As an
example,
the isolation can prevent the intermingling of water or gas that is present in
one section
with fluid hydrocarbons in another section. In wells where fracturizing or
"fracking" is
carried out to stimulate production of hydrocarbons, the isolation provided by
cementing
in the casing further assists in isolating the fracking operations to targeted
production
zones of the well.
[0003] It is known to use tools for cementing in the casing, which are placed
in line with
the casing when the casing is placed in the well bore. The prior art cementing
tools can
include movable sleeves that open ports extending through the sidewalls of the
tool to
allow cement injected into the casing to pass through the ports, and into the
annulus of
the well bore to cement in the casing. The ports can then be closed in the
tool by a
moving inner sleeve. Such tools comprise seals between the moving sleeves in
the tool
to close off the ports. The seals can include elastomer placed in grooves
disposed
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around the sleeves to providing the sealing contact between the sleeves. The
problem
with the prior art cementing tools is that the seals used in them are not
capable of
withstanding the fluid pressures used or required in fracking operations once
the casing
is cemented in. Fracking fluid pressures as high as 15,000 pounds per square
inch
("PSI") may be required to properly fracture or stimulate a production zone in
a well. As
the cementing tool is placed in-line with the casing, the pressurized fracking
fluid passes
through the cementing tool to reach the desired production zone. Pressurized
fracking
fluid has been known to cause seal failure in the cementing tool, wherein
fracking fluid
can leak through the compromised seals of the cementing tool, thus reducing
the
volume and pressure of the fracking fluid that can be delivered to the
production zone.
[0004] It is, therefore, desirable to provide a cementing tool that overcomes
the
shortcomings of prior art cementing tools.
SUMMARY:
[0005] A cementing tool is provided for use in cementing in casing or pipe in
a well bore,
so as to provide isolation between sections or production zones within a well
formation.
In some embodiments, the tool can comprise an outer sleeve and inner sleeve
slidably
disposed therein. The outer and inner sleeves can comprise aligned openings
that
allow cement to pass through once an opening seat disposed inside the inner
sleeve
slides down to expose the openings to the interior of the tool. Once the
cement has
been placed around the casing or pipe, the inner sleeve can slide downwards,
closing
off the openings of the outer sleeve. The inner sleeve can comprise
circumferential
seals placed therearound such that when the inner sleeve is moved downward to
a
lower position to close off the outer sleeve openings, the seals can straddle
these
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openings, thus closing off the openings. The seals themselves can comprise
convex
protrusions extending outwardly from the inner sleeve and configured to
contact the
inner wall of the outer sleeve in an interference fit. In this manner, the
seals can seal off
the outer sleeve openings from pressurized fracking fluid that is pumped
through the
tool and the casing, even at the high pressures used in fracking operations,
which can
reach as high as 15,000 PSI.
[0006] Broadly stated, in some embodiments, a cementing tool can be provided
for
cementing in a casing in well bore, the cementing tool comprising: a tubular
outer
sleeve defining a passageway therethrough, the outer sleeve comprising a first
upper
end configured to couple to a first pipe disposed thereabove, the outer sleeve
further
comprising at least one first opening disposed through a first sidewall of the
outer
sleeve; a tubular bottom subassembly operatively coupled to a first lower end
disposed
on the outer sleeve, the bottom subassembly configured to couple to a second
pipe
disposed therebelow; a tubular inner opening sleeve slidably disposed in the
outer
sleeve above the bottom subassembly; a tubular inner sleeve disposed in the
outer
sleeve above the inner opening sleeve, the inner sleeve further comprising at
least one
second opening disposed through a second sidewall of the inner sleeve, the
inner
sleeve comprising a first seal circumferentially disposed about the second
sidewall
above the at least one second opening, the inner sleeve comprising a second
seal
circumferentially disposed about the second sidewall above the first seal, the
inner
sleeve configured to move from a first upper position, wherein the at least
one second
opening is substantially aligned with the at least one first opening to
provide
communication between the at least one first opening and the passageway, to a
first
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lower position wherein the first seal is disposed below the at least one first
opening and
the second seal is disposed above the at least one first opening to prevent
communication between the at least one first opening and the passageway; and a
tubular opening seat slidably disposed between the inner sleeve and the inner
opening
sleeve, the tubular opening seat configured to move from a second upper
position,
wherein the tubular opening seat prevents communication between the at least
one first
opening and the passageway, to a second lower position wherein the at least
one first
opening is in communication with the passageway.
[0007] Broadly stated, in some embodiments, one or both of the first and
second seals
can be integral to the inner sleeve.
[0008] Broadly stated, in some embodiments, one or both of the first and
second seals
further can comprise an interference fit between the inner sleeve and the
outer sleeve.
[0009] Broadly stated, in some embodiments, one or both of the first and
second seals
can comprise a convex profile.
[0010] Broadly stated, in some embodiments, an outer diameter of one or both
of the
first and second seals can be greater than an inner diameter of the outer
sleeve.
[0011] Broadly stated, in some embodiments, the outer diameter can be greater
than
the inner diameter by a range of 0.007 inches to 0.012 inches.
[0012] Broadly stated, in some embodiments, the convex profile can comprise a
radius
in the range of 0.4 inches to 0.6 inches.
[0013] Broadly stated, in some embodiments, the convex profile can comprise a
width in
the range of 0.3 inches to 0.4 inches.
[0014] Broadly stated, in some embodiments, a method can be provided for
cementing
in a casing in a well bore, the method comprising the steps of: providing the
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abovementioned cementing tool configured for cementing in the casing in the
well bore;
placing the cementing tool in a string of casing pipe and inserting the string
into the well
bore; shutting off the string below the cementing tool; moving the tubular
opening seat
from the second upper position to the second lower position; and injecting
cementing
into the string wherein cement flows from the passageway through the at least
one first
and second openings into an annular space surrounding the casing.
[0015] Broadly stated, in some embodiments, when a sufficient amount of cement
has
been placed in the annular space, the method can comprise the step of moving
the
inner sleeve from the first upper position to the first lower position.
BRIEF DESCRIPTION OF THE DRAWINGS:
[0016] Figure 1 is a side elevation cut-away view depicting one embodiment of
a
cementing tool.
[0017] Figure 2 is an exploded view depicting the metal on metal seal feature
as shown
as Detail A in Figure 1.
[0018] Figure 3 is an exploded view depicting the metal on metal seal feature
as shown
as Detail B in Figure 1.
[0019] Figure 4 is a side elevation cross-section view depicting one
embodiment on an
inner sleeve for use with the tool of Figure 1.
[0020] Figure 5 is a cross-section view depicting the metal seal shown as
Detail C in
Figure 8.
[0021] Figure 6 is a top plan view depicting a guide slot of the inner sleeve
of Figure 8.
[0022] Figure 7 is a side cross-section view depicting one embodiment of the
inner and
outer sleeves of the tool of Figure 1 when in a run-in and open position.
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[0023] Figure 8 is a side cross-section view depicting the inner and outer
sleeves of
Figure 4 when in a closed position.
[0024] Figure 9 is a side elevation view depicting a shut-off plug and baffle
for use with
the tool of Figure 1.
[0025] Figure 10 is a side elevation view depicting a closing plug for use
with the tool of
Figure 1.
[0026] Figure 11 is a side elevation cross-section view depicting the tool of
Figure 1
being run-in a well bore.
[0027] Figure 12 is a side elevation cross-section view depicting the tool of
Figure 11
shown in an open position.
[0028] Figure 13 is a side elevation cross-section view depicting the tool of
Figure 11
shown in a closed position.
DETAILED DESCRIPTION OF EMBODIMENTS:
[0029] Referring to Figure 1, one embodiment of cementing tool 10 is shown. In
some
embodiments, tool 10 can comprise tubular housing or outer sleeve 12
threadably
coupled to tubular bottom subassembly or "sub" 14 via threaded end 15 threaded
into
threaded opening 17 to define passageway 20 extending from inlet coupling 16
to outlet
coupling 18. Inlet coupling 16 can comprise a threaded box end for threadably
coupling
to a section of casing disposed above tool 10. Outlet coupling 18 can comprise
a
threaded pin end for threadably coupling to another section of casing disposed
below
tool 10. In some embodiments, tool 10 can comprise tubular inner opening
sleeve 30
threaded into threaded opening 31 disposed on the upper end of bottom sub 14.
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[0030] In some embodiments, tool 10 can comprise inner sleeve 22 slidably
disposed
within outer sleeve 12. Inner sleeve 22 can be initially positioned within
outer sleeve 12
with a plurality of shear pins 27 extending from closing seat 24 of inner
sleeve 22 into
corresponding openings disposed on the inner wall of outer sleeve 12 such that
openings 36 extending through the sidewall of inner sleeve 22 are
substantially aligned
with openings 34 extending through the sidewall of outer sleeve 12. Each of
outer
sleeve 12 and inner sleeve 22 can comprise a plurality of openings 34 and 36,
respectively, extending through the sidewalls thereof. In some embodiments,
inner
sleeve 22 can comprise a plurality of vertical slots 60 disposed on the outer
sidewall
thereof, wherein slots 60 can be configured to receive setscrews 62 extending
inwardly
from the inner sidewall of outer sleeve 12. The combination of slots 60 and
setscrews
62 can limit the amount of travel inner sleeve 22 can move within outer sleeve
12 in a
vertical direction, and can further prevent inner sleeve 22 from twisting
within inner
sleeve 12, thus keeping openings 34 and 36 substantially aligned with each
other. The
length, depth and number of slots 60 can be chosen or selected as a matter of
design
considerations arising from the size and diameter of tool 10, the choice or
selection of
which is well known or obvious to those skilled in the art. In a
representative
embodiment, each of outer and inner sleeves 12 and 22 can comprise six
openings 34
and 36, respectively, disposed about the circumferences thereof, spaced
substantially
equidistant apart, and can further comprise six slots 60 and six setscrews 62
disposed
about the circumferences of inner and outer sleeves 22 and 12, respectively,
spaced
substantially equidistant apart.
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[0031] In some embodiments, tool 10 can comprise tubular opening seat 32
slidably
disposed within inner sleeve 22 and inner opening sleeve 30. In an initial
position,
opening seat 32 can be positioned in an upper position within inner sleeve 22
and inner
opening sleeve 30 wherein communication between passageway 20 and openings 34
and 36 is blocked.
[0032] Referring to Figures 1, 2 and 3, tool 10 can comprise seals 26 and 28
disposed
around the circumference of inner sleeve 22. Seal 26 can be disposed above
slot 60,
and seal 28 can be disposed below slot 60. In some embodiments, each of seals
26
and 28 can comprise a convex-shaped protrusion extending from outer sidewall
21 of
inner sleeve 22 such that seals 26 and 28 can contact inner sidewall 23 of
outer sleeve
12 in an interference fit. In some embodiments, the outer diameter of inner
sleeve 22
as defined by the outer edge of seals 26 and 28 can be 0.007 to 0.012 inches
greater
than the inner diameter of outer sleeve 12 as defined by inner sidewalls 23.
[0033] Referring to Figure 4, a cross-section view of one embodiment of inner
sleeve 22
is shown. In some embodiments, inner sleeve 22 can comprise grooves 64 and 66
configured for receiving elastomer o-rings seals to prevent fluids from
entering into an
annular space located between inner opening sleeve 30 and outer sleeve 12
which
would prevent inner sleeve 22 from fully descending within outer sleeve 12 to
fully close
off and seal openings 34. Inner sleeve 22 can further comprise threaded
opening 29
configured for threadably receiving closing seat 24.
[0034] Referring to Figure 5, a cross-section view of seal 26 or 28 is shown.
In some
embodiments, seal 26 or 28 can comprise a convex protrusion extending from
outer
sidewall 21 of inner sleeve 22. In some embodiments, the convex protrusion can
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comprise a radius R in the range of 0.4 inches to 0.6 inches. In a
representative
embodiment, radius R can be 0.5 inches. In some embodiments, the convex
protrusion
can comprise a width W in the range of 0.3 inches to 0.4 inches. In a
representative
embodiment, width W can range from 0.341 inches to 0.347 inches.
[0035] Referring to Figure 6, one embodiment of slot 60 is shown. The length
of slot 60
can be selected in accordance with the diameter of tool 10. When tool 10 is
configured
for use with a 4-1/2 inch casing, slot 60 can be milled to be 2.00 inches long
and 0.562
inches wide, to a depth of 0.090 inches. When tool 10 is configured for use
with a 9-5/8
inch casing, slot 60 can be milled to be 2.50 inches long and 0.562 inches
wide, to a
depth of 0.090 inches.
[0036] Referring to Figures 7 and 8, representations of outer and inner
sleeves 12 and
22 are shown. When inner sleeve 22 is in an upper position within outer sleeve
12, both
of seals 26 and 28 are positioned above opening 34. When inner sleeve 22 is in
a
lower position within outer sleeve 12, seal 26 is positioned above opening 34
whereas
seal 28 is positioned below opening 34 thus enclosing opening 34 between seals
26
and 28 and, thus, preventing any communication between opening 34 and
passageway
20. The diameter of openings 34 and 36 can be chosen or selected in accordance
with
design considerations arising from the diameter of tool 10, the choice or
selection of
which is well known or obvious to those skilled in the art. When tool 10 is
configured for
use with a 4-1/2 inch casing, openings 34 and 36 can be 0.81 inches in
diameter.
When tool 10 is configured for use with a 9-5/8 inch casing, openings 34 and
36 can be
1.13 inches in diameter.
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[0037] Referring to Figure 9, one embodiment of a shut off plug and baffle for
use with
tool 10 is shown, as shown in Figures 11, 12 and 13 and discussed in further
detail
below. In some embodiments, baffle 38 can comprise a tubular subassembly that
can
be placed between adjoining sections of casing 8 joined together with coupler
9, as
shown in Figures 11 to 13. Baffle 38 can further comprise frustoconical-shaped
seat 39
configured to receive frustoconical-shaped plug 48 disposed on a lower end of
shut off
plug 40. Plug 40 can further comprise cup 42 connected to plug 48 via plug
shaft 46.
Plug 40 can further comprise a plurality of circumferential fins 44 disposed
around shaft
46.
[0038] Referring to Figure 10, one embodiment of closing plug 50 for use with
tool 10 is
shown, as shown in Figure 13 and discussed in further detail below. In some
embodiments, plug 50 can comprise cup 52 connected to frustoconical-shaped
plug 58
via plug shaft 56. Plug 50 can further comprise a plurality of circumferential
fins 54
disposed around shaft 56. Plug 58 can be configured to seat in frustoconical-
shaped
seat 25 disposed in closing seat 24.
[0039] Referring to Figure 11, tool 10 is shown coupled between sections of
casing 8 via
coupling 9 when the casing is being run into a well bore. In this
configuration, opening
seat 32 is in an upper position wherein openings 36 are closed off from
passageway 20.
Once the casing has been run in to its position within the well bore, tool 10
can then be
operated to cement in the casing in the region surrounding tool 10.
[0040] Referring to Figure 12, shut off plug 40 is run down casing 8 followed
by
displacement fluid, such as water, drilling mud, brine water or other like
fluid as well
known to those skilled in the art, to push shut off plug 40 down the casing.
Fins 44 and
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cup 42 help keep shut off plug 40 centered and stable in the casing as it
makes its way
down the casing, and through tool 10 to seat on baffle 38 where plug 48 seats
on seat
39. Once shut off plug 40 is seated, cement can then be injected into casing 8
and
down to tool 10 located above shut off plug 40. The hydraulic pressure of the
cement
can then also cause opening seat 32 to travel downward, sliding into inner
opening
sleeve 30, to reveal openings 36, which can be substantially aligned with
openings 34.
Once opening seat 32 is pushed downwards to a lower position where opening
seat 32
is in contact with inner opening sleeve 30, the pressurized cement can then
exit tool 10
by passing through openings 36 and 34, and into the annular space surrounding
tool 10
and the casing in the well bore, thus cementing in the casing in the well
bore. When a
sufficient amount of cement has been placed, closing plug 50 can be run down
the
casing with displacement fluid until it contacts closing seat 24. Fins 54 and
cup 52 help
keep closing plug 50 centered and stable as it makes its way down the casing,
and any
tools placed in line with the casing above tool 10.
[0041] Referring to Figure 13, closing plug 50 is shown seated in closing seat
24
wherein plug 58 is firmly seated in seat 25. The hydraulic pressure of the
cement/fluid
pushing downward on plug 50 can shear shear pins 27, thus allowing inner
sleeve 22 to
move downward, guided by setscrews 62 extending into slots 60, and then close
off
openings 34 as seal 28 slides downward below openings 34 when inner sleeve 22
reaches a lower position where inner sleeve 22 contacts bottom sub 14.
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[0042] In one test that was conducted on a tool configured as a 5-1/2", 26
pound, P-110
Hydraulic Ball Seal Stage Cementing tool, the following steps and results were
carried
out and observed:
1. The inner sleeve was installed into housing with a hydraulic press at
18,860 lbs of force.
2. The opening seat assembly and bottom sub was installed into the tool.
3. The test caps were installed on both ends of the tool.
4. Pressure was applied and the opening seat opened at 4000 PSI with 7 -
3/8" (.268) brass pins.
5. The top test cap was removed to install the closing plug was installed, the
top test cap was then reinstalled.
6. Pressure was applied and the inner sleeve started to close at 800 PSI, the
pressure dropped to 400 PSI as the tool closed, but came back to 800 PSI
at complete close, with the pressure being raised to 3200 PSI and held at
this pressure for 3 minutes.
7. The top test cap was removed to remove the closing plug, with the top test
cap then being reinstalled.
8. Pressure was applied to the tool up to 15,000 PSI for 22 cycles at 10
minutes per each cycle.
9. No leaks were observed in the tool.
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[0043] In another test that was conducted on a tool configured as a 7", 41
pound, P-110
Hydraulic Ball Seal Stage Cementing tool, the following steps and results were
carried
out and observed:
1. The inner sleeve was installed into housing with a hydraulic press at
25,380 lbs of force.
2. The opening seat assembly and bottom sub was installed into the tool.
3. The test caps were installed on both ends of the tool.
4. Pressure was applied and the opening seat opened at 3000 PSI with 7 -
3/8" (.265) brass pins.
5. The top test cap was removed to install the closing plug was installed, the
top test cap was then reinstalled.
6. Pressure was applied and the inner sleeve started to close at 500 PSI, the
tool was closed at 800 PSI, with the pressure being raised to 3200 PSI
and held at this pressure for 2 minutes.
7. The top test cap was removed to remove the closing plug, with the top test
cap then being reinstalled.
8. Pressure was applied to the tool up to 15,000 PSI for 22 cycles at 10
minutes per each cycle.
9. No leaks were observed in the tool
[0044] In the foregoing disclosure, the description and operation of tool 10
has been
provided. While the placement and operation of a single tool 10 to cement in
casing in
a well bore has been discussed, it should also be well known or obvious to
those skilled
in the art that two or more tools 10 can be placed in line with a casing
placed in a well
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bore to permit the cementing in of the casing at various locations or stages
to provide
multiple, cemented-in production zones in the formation. This can take place
in
vertically-drilled wells, or in diagonally-drilled or horizontally-drilled
wells.
[0045] Although a few embodiments have been shown and described, it will be
appreciated by those skilled in the art that various changes and modifications
can be
made to these embodiments without changing or departing from their scope,
intent or
functionality. The terms and expressions used in the preceding specification
have been
used herein as terms of description and not of limitation, and there is no
intention in the
use of such terms and expressions of excluding equivalents of the features
shown and
described or portions thereof, it being recognized that the invention is
defined and
limited only by the claims that follow.
