U.S. patent application number 13/247583 was filed with the patent office on 2012-03-29 for downhole catcher for an actuating ball and method.
This patent application is currently assigned to PACKERS PLUS ENERGY SERVICES INC.. Invention is credited to ROBERT JOE COON, MICHAEL KENYON, DANIEL JON THEMIG, JOHN THOMAS ZUKOWSKI.
Application Number | 20120073827 13/247583 |
Document ID | / |
Family ID | 45869463 |
Filed Date | 2012-03-29 |
United States Patent
Application |
20120073827 |
Kind Code |
A1 |
KENYON; MICHAEL ; et
al. |
March 29, 2012 |
DOWNHOLE CATCHER FOR AN ACTUATING BALL AND METHOD
Abstract
A ball catching device has been invented that catches an
actuator ball used in a wellbore to actuate a downhole tool. The
device catches the ball downhole as it begins to flow back with
fluids toward surface. The device is configured such that when a
ball flows back with wellbore fluids, the ball can flow through the
device and if the ball reverses direction, as by falling back due
to decreased or stopped production back flow, then the device will
catch the ball and keep it from falling back past the device into
the well.
Inventors: |
KENYON; MICHAEL; (Calgary,
CA) ; COON; ROBERT JOE; (Missouri City, TX) ;
THEMIG; DANIEL JON; (Calgary, CA) ; ZUKOWSKI; JOHN
THOMAS; (Calgary, CA) |
Assignee: |
PACKERS PLUS ENERGY SERVICES
INC.
Calgary
CA
|
Family ID: |
45869463 |
Appl. No.: |
13/247583 |
Filed: |
September 28, 2011 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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61387850 |
Sep 29, 2010 |
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Current U.S.
Class: |
166/373 ;
166/193 |
Current CPC
Class: |
E21B 34/14 20130101;
E21B 34/107 20130101 |
Class at
Publication: |
166/373 ;
166/193 |
International
Class: |
E21B 34/06 20060101
E21B034/06; E21B 33/12 20060101 E21B033/12 |
Claims
1. A downhole ball catcher for preventing an actuation ball
migrating upwardly through a well from falling back down deeper
into the well after passing upwardly through the downhole ball
catcher, the downhole ball catcher comprising: a main housing sized
to be positioned downhole in the well and including a bottom end, a
top end, an inner open area and openings for fluid flow from the
bottom end, through the inner open area and out through the top
end; and a protrusion connected by a moveable connection to the
main housing and positioned in the inner open area in a blocking
position to block passage of a ball through the inner open area,
the moveable connection being configured to allow movement of the
protrusion away from the blocking position in response to a ball
pushing upwardly past the protrusion toward the top end and the
moveable connection being configured to resist movement of the
protrusion away from the blocking position to prevent movement of
the ball downwardly past the protrusion toward the bottom end.
2. The downhole ball catcher of claim 1 wherein the moveable
connection includes at least one of a pivot, a flexing member or a
slider/groove.
3. The downhole ball catcher of claim 1 wherein the moveable
connection is resilient biasing the protrusion to the blocking
position.
4. The downhole ball catcher of claim 1 further comprising a
fishing structure for accepting engagement of a retrieval tool.
5. The downhole ball catcher of claim 1 further comprising a
connection to a retrieval tool.
6. The downhole ball catcher of claim 1 wherein the top end is open
and sized to allow the ball to pass.
7. The downhole ball catcher of claim 1 formed as a separate
structure and independently positionable in the well.
8. The downhole ball catcher of claim 1 wherein the main housing is
installed as part of a tubing string with the inner open area open
to the tubing string's inner bore.
9. The downhole ball catcher of claim 8 wherein the tubing string
is a frac string through which wellbore stimulation fluids are
injected into the well.
10. The downhole ball catcher of claim 8 wherein the bottom end is
formed for accepting connection to a lower portion of the string
and the top end is formed for accepting connection of an upper
portion of the string.
11. The downhole ball catcher of claim 1 further comprising an
activation mechanism for maintaining the protrusion in an inactive
position and operable to move the protrusion into an active
position.
12. The downhole ball catcher of claim 11, wherein the activation
mechanism an openable sleeve behind which the protrusion are
retracted when in the inactive position.
13. The downhole ball catcher of claim 12 wherein openable sleeve
is moveable by sliding to release the protrusion to assume the
active position.
14. The downhole ball catcher of claim 12 wherein the openable
sleeve includes a seat on its inner diameter sized to catch and
create a seal with a ball such that pressure can be built up behind
the ball sufficient to shift the sleeve to release the
protrusion.
15. A wellbore assembly comprising: an actuator ball in the well
useful to actuate a downhole tool and moveable to migrate upwardly
in the well as driven by back flow of wellbore fluids; and an
actuator ball catching device positioned in a lower portion of the
well above the actuator ball, the device including a main housing
with a fluid flow passage from a bottom end to an upper end and
formed to be removable from the well by pulling to surface and the
device having a mechanism to allow the passage of an actuator ball
moving up through the device, the mechanism preventing the actuator
ball from moving down past the device into the well.
16. The wellbore assembly of claim 15 wherein the mechanism
includes a plurality of protrusions acting as a one-way valve for
the actuator ball to allow movement of the actuator ball in an
upward direction, while preventing movement of the actuator ball
downward through the actuator ball catching device.
17. The wellbore assembly of claim 15 wherein the mechanism
includes a protrusion connected by a moveable connection to the
main housing and positioned in the inner open area in a blocking
position to block passage of a ball through the inner open area,
the moveable connection configured to allow movement of the
protrusion away from the blocking position to allow movement of the
actuator ball upwardly past the protrusion toward the top end and
the moveable connection configured to resist movement of the at
least one protrusion away from the blocking position to allow
movement of the actuator ball downwardly past the protrusion toward
the bottom end.
18. The wellbore assembly of claim 15 wherein the moveable
connection includes at least one of a pivot, a flexing member or a
slider/groove.
19. The wellbore assembly of claim 15 wherein the moveable
connection is resilient biasing the protrusion to the blocking
position.
20. The wellbore assembly of claim 15 further comprising a fishing
structure for accepting engagement of a retrieval tool.
21. The wellbore assembly of claim 15 further comprising a
connection to a retrieval tool.
22. The wellbore assembly of claim 15 wherein the top end is open
and sized to allow the ball to pass.
23. The wellbore assembly of claim 15 formed as a separate
structure and independently positionable in the well.
24. The wellbore assembly of claim 15 wherein the main housing is
installed as part of a tubing string with the inner open area open
to the tubing string's inner bore.
25. The wellbore assembly of claim 24 wherein the tubing string is
a frac string through which wellbore stimulation fluids are
injected into the well.
26. The wellbore assembly of claim 24 wherein the bottom end is
formed for accepting connection to a lower portion of the string
and the top end is formed for accepting connection of an upper
portion of the string.
27. The wellbore assembly of claim 15 further comprising an
activation mechanism for maintaining the protrusion in an inactive
position and operable to move the protrusion into an active
position.
28. The wellbore assembly of claim 27, wherein the activation
mechanism an openable sleeve behind which the protrusion are
retracted when in the inactive position.
29. The wellbore assembly of claim 28 wherein openable sleeve is
moveable by sliding to release the protrusion to assume the active
position.
30. The wellbore assembly of claim 28 wherein the openable sleeve
includes a seat on its inner diameter sized to catch and create a
seal with a ball such that pressure can be built up behind the ball
sufficient to shift the sleeve to release the protrusion.
31. A method for catching an actuation ball from a wellbore, the
method comprising: positioning an actuator ball catching device
downhole in a wellbore; back flowing wellbore fluids to push an
actuator ball along the wellbore to the actuator ball catching
device; catching the actuator ball by allowing the actuator ball to
move up through the actuator ball catching device, the actuator
ball catching device catching the actuator ball by preventing the
actuator ball from falling back down into the well; and retrieving
the actuator ball catching device to surface along with the
actuator ball caught in the actuator ball catching device.
32. The method of claim 31 wherein the actuator ball catching
device includes a protrusion acting as a one-way valve for the
actuator ball and wherein during catching the actuator ball passes
upwardly through the plurality of protrusions and thereafter cannot
pass downwardly through the protrusions.
33. The method of claim 31 wherein positioning includes dropping
the actuator ball catching device into the wellbore or running the
actuator ball catching device into the wellbore using a string.
34. The method of claim 31 wherein positioning places the actuator
ball catching device low down in the wellbore.
35. The method of claim 31 wherein the wellbore includes a liner
installed therein and positioning places the actuator ball catching
device adjacent the upper end of the liner.
36. The method of claim 35, wherein catching occurs uphole of the
liner.
37. The method of claim 31 further comprising launching the
actuator ball after positioning.
38. The method of claim 31 further comprising launching the
actuator ball before positioning.
39. The method of claim 31 wherein retrieving uses a string or a
pressure driven seal.
40. The method of claim 31 further comprising activating the
actuator ball catching device after positioning.
41. The method of claim 31 wherein during positioning the actuator
ball catching device is in an inactive condition and after
positioning the method further comprises launching the actuator
ball and activating the actuator ball catching device.
42. The method of claim 31 further comprising opening a drain port
and allowing the fluid to drain from above the actuator ball caught
in the actuator ball catching device.
Description
FIELD
[0001] The present invention relates to wellbore tools,
installations and processes. In particular, a downhole tool for
addressing the use of downhole tool actuators, herein referred to
as actuating balls.
BACKGROUND
[0002] Some wellbore processes employ actuators to activate
downhole tools. For example, in some wellbore stimulation
processes, as described in U.S. Pat. No. 7,861,774 and U.S. Pat.
No. 7,748,460, both for Packers Plus Energy Services Inc.,
actuators of various sizes are employed to activate sliding sleeves
such as those over frac ports. As described therein, stimulation of
vertical and horizontal wells may proceed by dropping actuators to
actuate the sliding sleeves. The actuators can be in the shape of
balls, plugs, darts, etc., but are commonly referred to as
balls.
[0003] In certain cases, it may be necessary to retrieve all balls
from the wellbore that were used to actuate downhole tools. For
example, after deploying balls, it may be of interest to go in and
do some kind of an intervention in the well. For example, an
operation could be undertaken to shift previously opened sleeves to
closed positions for example to re-frac the well or to shut off
water. As another example, it may be of interest to do a production
log, which is run typically on coiled tubing or jointed tubing. If
the balls remain in the well, one or more of the balls may prevent
the strings/tools from achieving total depth. A ball may blank off
the operation.
[0004] It has been believed that balls will work their way out of
the well by flow back. In particular, after a ball is pumped and
used to actuate a downhole tool, the operator may begin to flow the
well back. When the well begins to flow back, the balls generally
begin to move with the flowing fluids back up the well. The balls
typically will move along the base of the horizontal well and to
the heel of the well without much problem. However, when the balls
reach a vertical section, the lifting forces of the fluid may be
inadequate to continue to carry the balls. As such, the balls tend
to flow up to a certain point in the well but they may not flow all
the way up to surface.
SUMMARY
[0005] In accordance with broad aspects of the present invention,
there are provided a catcher for a wellbore actuation ball, a
wellbore assembly and a method for wellbore operations.
[0006] For example, in one aspect, there is a provided a downhole
ball catcher for preventing an actuation ball migrating upwardly
through a well from falling back down deeper into the well after
passing upwardly through the downhole ball catcher, the downhole
ball catcher comprising: a main housing sized to be positioned
downhole in the well and including a bottom end, a top end, an
inner open area and openings for fluid flow from the bottom end,
through the inner open area and out through the top end; and a
protrusion connected by a moveable connection to the main housing
and positioned in the inner open area in a blocking position to
block passage of a ball through the inner open area, the moveable
connection being configured to allow movement of the protrusion
away from the blocking position in response to a ball pushing
upwardly past the protrusion toward the top end and the moveable
connection being configured to resist movement of the protrusion
away from the blocking position to prevent movement of the ball
downwardly past the protrusion toward the bottom end.
[0007] In a further aspect there is provided a wellbore assembly
comprising: an actuator ball in the well useful to actuate a
downhole tool and moveable to migrate upwardly in the well as
driven by back flow of wellbore fluids; and an actuator ball
catching device positioned in a lower portion of the well above the
actuator ball, the device including a main housing with a fluid
flow passage from a bottom end to an upper end and formed to be
removable from the well by pulling to surface and the device having
a mechanism to allow the passage of an actuator ball moving up
through the device, the mechanism preventing the actuator ball from
moving down past the device into the well.
[0008] In a further aspect there is provided a method for catching
an actuation ball from a wellbore, the method comprising:
positioning an actuator ball catching device downhole in a
wellbore; back flowing wellbore fluids to push an actuator ball
along the wellbore to the actuator ball catching device; catching
the actuator ball by allowing the actuator ball to move up through
the actuator ball catching device, the actuator ball catching
device catching the actuator ball by preventing the actuator ball
from falling back down into the well; and retrieving the actuator
ball catching device to surface along with the actuator ball caught
in the actuator ball catching device.
[0009] It is to be understood that other aspects of the present
invention will become readily apparent to those skilled in the art
from the following detailed description, wherein various
embodiments of the invention are shown and described by way of
illustration. As will be realized, the invention is capable for
other and different embodiments and its several details are capable
of modification in various other respects, all without departing
from the spirit and scope of the present invention. Accordingly the
drawings and detailed description are to be regarded as
illustrative in nature and not as restrictive.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] Referring to the drawings, several aspects of the present
invention are illustrated by way of example, and not by way of
limitation, in detail in the figures, wherein:
[0011] FIGS. 1A, 1B and 1C are a series of schematic illustrations
of one embodiment of a downhole ball catcher in section in a well
and a method for catching an actuation ball. FIG. 1A illustrates
the ball catcher in position in a well with a ball approaching the
ball catcher from below as driven by flow back. FIG. 1B illustrates
the ball moving upwardly through the protrusions of the ball
catcher, as driven by flow back, with the protrusions flexing out
of the way to permit the movement. FIG. 1C illustrates the ball
caught in the ball catcher, the protrusions holding the ball in the
ball catcher and ball being unable to move back downhole since the
protrusions stop such movement.
[0012] FIGS. 2A, 2B and 2C are a series of schematic illustrations
of one embodiment of a downhole ball catcher in quarter section and
a method for activating the ball catcher. FIG. 2A shows the ball
catcher in a run in position with an activation ball just landed
therein. FIG. 2B shows the ball catcher after activation. FIG. 2C
shows the ball catcher activated and having operated to catch an
actuator ball. FIG. 2D shows a bottom perspective view of a ball
catcher, with a section through the housing oriented with reference
to line I-I in FIG. 2C.
[0013] FIGS. 3A to 3D are a series of schematic illustrations of
one embodiment of a downhole ball catcher in section in tubing
string in a well and a method for catching a plurality of actuation
balls. FIG. 3A illustrates the ball catcher incorporated in a
tubing string and in position in a well in an inactive position,
where it has not interfered with actuation balls conveyed to drive
processes below the ball catcher. FIG. 3B illustrates the ball
catcher being activated by an activation ball. In FIG. 3C, the ball
catcher has caught a plurality of actuation balls including the
activation ball used to activate it. FIG. 3D shows the tubing
string being pulled toward surface with the balls remaining in the
ball catcher and also, therefore, being retrieved.
[0014] FIGS. 4A, 4B and 4C are a series of schematic illustrations
of one embodiment of a downhole ball catcher in quarter section and
a method for activating the ball catcher. FIG. 4A shows the ball
catcher with balls caught therein. FIG. 4B shows the ball catcher
before a bypass is opened. FIG. 4C shows the ball catcher the ball
catcher after a bypass is opened.
[0015] FIG. 5 is a partial sectional view through another all
catcher.
[0016] FIGS. 6A and 6B are a series of schematic illustrations of
the ball catcher of FIG. 5 in a well and a method for catching a
plurality of actuation balls. FIG. 6A illustrates the ball catcher
in position in a well in an active position. FIG. 6B shows the ball
catcher being pulled toward surface with balls caught in the ball
catcher.
DETAILED DESCRIPTION OF VARIOUS EMBODIMENTS
[0017] The description that follows, and the embodiments described
therein, is provided by way of illustration of an example, or
examples, of particular embodiments of the principles of various
aspects of the present invention. These examples are provided for
the purposes of explanation, and not of limitation, of those
principles and of the invention in its various aspects. The
drawings are not necessarily to scale and in some instances
proportions may have been exaggerated in order more clearly to
depict certain features. Throughout the drawings, from time to
time, the same number is used to reference similar, but not
necessarily identical, parts.
[0018] Actuation balls are used in wellbore actuation. As noted
above, if an actuator ball remains in the wellbore, wellbore
interventions may be impossible or complicated. Flow back, while
sometimes successful to remove the balls, cannot be relied upon in
all situations. However, if the balls are removed from the well, it
may be more readily possible to run tools or strings in to actuate
well apparatus or to inspect or treat the well. If the balls can be
removed, they won't create restrictions in the well. Thus, the
ability to retrieve all the actuation balls is beneficial
especially if intervention techniques are to be attempted
thereafter.
[0019] While the term ball is used, it is to be understood that the
term can broadly be used to refer to non-spherical actuators, such
as rods, darts, etc., sometimes also referred to as actuator plugs
or actuator tools. Also, while a particular device may be deployed,
it may break apart downhole and the resultant broken parts may also
be problematic. It is intended that all such components including
balls, plugs, tools, and broken pieces thereof are encompassed by
the term balls.
[0020] A ball catching device has been invented that catches an
actuator ball used to actuate a downhole tool. The device catches
the ball downhole as it begins to flow back with fluids toward
surface. The device is configured such that when a ball flows back
with wellbore fluids, the ball can flow through the device and if
the ball reverses direction, as by falling back due to decreased or
stopped production back flow, then the device will catch the ball
and keep it from falling back past the device into the well.
[0021] With reference to FIGS. 1A to 1C, a ball catcher device
includes a main housing 12 with an inner open area 14 and one or
more protrusions 16 in the inner open area moveably connected to
the main housing 12. The one or more protrusions are configured via
their moveable connection 18 to allow a ball 15 to move, arrow A,
upwardly therethrough toward surface (FIG. 1B). The one or more
protrusions are also configured via their moveable connection 18 to
block any reverse movement of that ball downwardly therepast (FIG.
1C).
[0022] Protrusion 16 may take various forms. A protrusion may be,
for example, a finger, a collet, a flapper, a dog, etc.
[0023] Moveable connection 18 may take various forms including any
of pivots, flexing members, sliders, etc. For example, as shown,
moveable connection 18 may be formed as flexible base portions 24
of the protrusions. The flexible base portions are formed of
material such as resilient steel angled in a direction that allows
each protrusion to flex between a blocking position and a position
allowing upward movement therepast, but resist any movement from
the blocking position to a position allowing downward movement
therepast. As such, flexible base portions 24 allow a ball to push
the protrusions out of the way when the ball is moving upwardly
against the protrusions. However, once the ball passes the
protrusions, the protrusions flex back into the blocking position
and if the ball reverses direction and attempts to move back down
in the well, the protrusions cannot flex past the blocking position
and the protrusions resist downward movement of the ball
therethrough.
[0024] Inner open area 14 is sized to accommodate at least one ball
15 to be caught.
[0025] Main housing 12 and protrusions 16 may be formed to allow
fluid flow therethrough, such as for example, flow from a bottom
end 12a of the main housing, past protrusions 16 and out through a
top end 12b of the main housing such that fluid flow, arrows F,
toward surface is not sealed off. Main housing 12 can take various
forms. For example, main housing 12 may be formed as a tubular
member for example with inner open area passing through and being
open at the bottom and top ends. The main housing can: have solid
walls or perforated walls, be shaped in various ways; and/or can
include locking structures for locking to a wellbore structure or
fishing structures such as an upper gland 20 for accepting
engagement of a retrieval tool.
[0026] The basket can be open topped, with end 12b having a
diameter sized to allow an actuator ball to pass through, since
upward further travel of the balls past the basket toward or fully
to surface is not a problem.
[0027] The ball catcher device may be a separate structure, as
shown in FIG. 1, independently positionable in a well 22 or may be
installed as part of a tubing string, as shown in later
Figures.
[0028] As a separate structure, the ball catcher device may be
likened to a basket that is sized to be moved through the well to
be installable to catch one or more balls and, thereafter,
retrievable to carry any caught balls out of the well. The basket
can catch one or more of the balls in the well, but allow fluid to
pass therethrough. The basket can be released from surface and
moved by pumping or gravity, mechanically run on a string such as
tubing (i.e. jointed tubing, coiled tubing, etc.) or wireline (i.e.
slickline, braided line, e-line, control line, etc.) or connected
to and carried into the well on another wellbore apparatus, such as
the tubing string to be actuated. Once in place, it may simply rest
unsecured in well 12 (as shown) or it may lock into a structure in
the well.
[0029] The protrusions act like a one-way valve for the ball,
acting to allow the ball's movement in one direction, while
restricting the ball's movement in the opposite direction. The
device is positioned such that the protrusions restrict the ball
from moving downwardly therepast, but allow the ball to move
upwardly therepast.
[0030] When the well is flowed back, any balls in the well such as
ball 15 will start to move uphole toward surface. As a ball
approaches the protrusions from below, the protrusions are
initially in a blocking position (FIG. 1A) but the protrusions are
only active to prevent downward movement of the ball, such that the
ball is able to come up through protrusions 16 into inner open area
14 of the basket above the protrusions. As shown in FIG. 1B, the
protrusions can move, arrows M, out of the way of a ball passing in
a first direction up therethrough and, therefore, allow the ball to
pass. In this operation, the protrusions move along arrows M in a
direction out of the blocking position. One or more of the
protrusions of the mechanism may be moved by a ball pushing
upwardly therepast.
[0031] The protrusions resist movement away from the blocking
position in a direction opposite to the above-noted direction out
of a blocking position. For example, if any ball that has passed
the protrusions upwardly, moves back against the protrusions, as by
falling back by gravity, the protrusions cannot move to allow
passage of the ball (FIG. 1C). Thus, the one or more balls can flow
into the basket but they can't pass back out the bottom of the
basket past the protrusions.
[0032] When the balls have been caught in the basket, the basket
can be retrieved. For example, the basket can be retrieved using
any of the various means for tool retrieval including pressure,
tubing, wireline, etc., as noted above with respect to deployment.
Alternately, a seal device can be launched, for example, and
conveyed by gravity or pressure to latch onto the basket, for
example into gland 20. The seal can then be acted upon by fluid
pressure from below, to flow the seal device and the basket back to
surface.
[0033] The ball catcher device according to the present invention
may be installed low down in well 22, at a position that can be
reached by the balls during normal back flow. When positioning the
ball catcher device, the back flow driven movement of even the
smallest balls should be considered, as they do not create a lot of
hydraulic back pressure and tend to move the least. The ball
catcher device may be low down in the well for example, in the
horizontal section, in the heel or in a lower vertical section of
well 22.
[0034] In another embodiment, as shown in FIGS. 2 and 3, the ball
catching device 100 may be incorporated in a tubing string 130 and
positioned in a well 122 along with the tubing string. The tubing
string may take various forms, but herein is shown as a frac
string.
[0035] Ball catcher device 100 includes a main housing 112 with an
inner open area 114 and one or more protrusions 116 in the inner
open area moveably connected to the main housing 112. FIG. 2D shows
a possible arrangement of protrusions circumferentially around the
inner wall 112c of the main housing. The one or more protrusions
are configured via their moveable connection to allow a ball to
move upwardly therethrough in a direction toward surface. As shown
in FIG. 3C, the one or more protrusions are also configured via
their moveable connection to block any reverse movement of that
ball 140, 115a, 115b downwardly therepast.
[0036] Inner open area 114 is sized to accommodate at least one
ball 140, 115a, 115b to be caught by device 100.
[0037] Main housing 112 can take various forms, but at least
supports an installation of the device in a tubing string. For
example, main housing 112 may be formed as a tubular member having
a bottom end 112a formed for accepting connection to a lower
portion of string 130 and a top end 112b formed for accepting
connection of an upper portion of string 130. The end may be formed
by threading, quick connects, tapering, etc. to permit connection,
depending on the form of the tubing string whether it be
interconnected tubulars, coiled tubing, etc. Inner open area 114
may extend between and open at ends 112a, 112b such that area 114
is in open communication with inner bore 132 of the tubing string
and fluid passing through the string's inner bore 132 also passes
through area 114. Protrusions 116 also allow fluid flow
therepast.
[0038] Because the ball catching device is installed in tubing
string 130 and, in this embodiment, the tubing string is used for
wellbore operations including the passing of balls 115a, 115b
therethrough, device 110 includes an activation mechanism 134 that
allows the device to be maintained in an inactive position (FIG.
2A) and then activated to an active position (FIG. 2B). If the ball
catching device is installed after any need to move balls down
therepast, then a mechanism for activation need not be considered,
as the device could be run in in the active position without
concern.
[0039] Activation mechanism 134 may take various forms and be
operated in various ways. For example, in one embodiment, the
protrusions may be held in an inactive position, retracted behind
an openable sleeve 136. Protrusions 116 may be installed in or
adjacent to an annular recess 138 opening from area 114 in the
inner wall of main housing 112 and openable sleeve 136 may be
positioned in the main housing open inner area 114 extending across
at least the ends of protrusions 116, while the protrusions are
positioned in the recess. With openable sleeve 136 overlying
protrusions 116, they are held in this retracted position (FIG.
2A). The device may be activated in numerous possible ways,
including for example, hydraulic drives, physical manipulation from
surface, signaling, or pressure drive, including by use of a timer,
a conveyed tool such as a drop bar, plug (ball, dart, etc.),
control line, hydraulic, electronic, etc. In one embodiment, for
example, the frac string and/or the annulus could be pressured up
to shift the sleeve away from the protrusions. In another
embodiment, wireline or coiled tubing may be run in to shift the
sleeve away and, thus, allow the protrusions to be released into an
active position. In yet another embodiment, an electronic mechanism
or radio signal can signal the protrusions to be released. The
illustrated mechanism 134 allows openable sleeve 136 to be moved to
release protrusions 116 by engagement of the sleeve with an
activation ball 140 passing downwardly thereby. Sleeve 136,
therefore, includes a seat 142 on its inner diameter sized to catch
and create a seal with ball 140 such that pressure can be built up
behind the ball sufficient to shift the sleeve away from its
overlying position over protrusions 116. A shear pin 143 may be
employed to releasably control the movement of the sleeve. In the
illustrated embodiment, ball 140 is launched for the sole purpose
of activating device 100. In particular, after ball 140 shifts
sleeve 136 and pressure is reduced from surface, the ball can flow
back from seat 142 through the (now activated) protrusions. Ball
140 is then caught from falling back down into seat 142 in the same
way as the other actuation balls are caught by protrusions 116. In
another embodiment, the ball launched to activate the protrusions
may also be the last ball needed to actuate a tool downhole of the
ball catchers. For example, in a frac job, the ball, when launched,
can cause the protrusions to be released as it passes them. Then
the ball can pass to a frac port below the protrusions to open the
frac port such that frac fluid can be flowed therethrough. In such
an embodiment, the seat of the activation mechanism may be
deformable to allow the ball to pass both downhole and back up such
that the ball, when flowing back can reach and move through the
protrusions. Thus, the activation ball can be used to conduct other
wellbore processes or can be launched only for the purpose of
actuating the ball catcher. In any event, ball 140 can be caught by
the protrusions when it flows back.
[0040] In the active position, the protrusions are initially in a
blocking position (FIG. 2C). When the well is flowed back, ball 140
and other actuation balls in the well below are able to come up
through protrusions 116 into inner open area 114 between
protrusions 116 and open top end 112b. Once above the protrusions,
the balls cannot pass back down through the protrusions, as the
protrusions block such movement. In particular, protrusions 116 are
moveable between the blocking position and a position allowing
upward movement of a ball therethrough. In the position allowing
upward movement of a ball therethrough, the protrusions are pushed
out of the way of a ball passing in a first direction up
therethrough and, therefore, allow the ball to pass. In this
operation, the protrusions move along arrow B in a direction out of
the blocking position. However, protrusions 116 resist any movement
from the blocking position to a position allowing downward movement
of a ball therethrough, for example, such as if a ball, once above
the protrusions, moves back against the protrusions, as by falling
back by gravity.
[0041] Moveable connection 118 may incorporate various mechanisms
to permit such protrusion operation including any of pivots,
flexing members, sliders, etc. For example, as shown, moveable
connection 118 includes a pivotal connection 144 on the base of
each protrusion through which it is connected to the main housing
wall. The protrusions, as permitted by their pivotal connections
144 can pivot radially outwardly or inwardly to increase or
decrease, respectively, the space between the tips of the
protrusions, which is the space through which the balls will
travel. When the protrusions have applied thereto a force by a ball
being pushed thereagainst from below, the protrusions can pivot up
and out, arrow B, toward the housing walls to increase the space
between the tips 116a of protrusions 116. When the force is
removed, the protrusions can pivot back in toward the center axis
x, which decreases the space between the tips of protrusions 116.
Thus, once the ball passes upwardly through the protrusions, the
protrusions fall back into the blocking position, and cannot pivot
down beyond this position such that the protrusions resist downward
movement of the ball.
[0042] It is noted that the protrusions in this illustrated
embodiment may also be resilient to some degree to allow them (i)
to be moved behind sleeve 136 and (ii) to pop out into an active
position, when the sleeve is removed.
[0043] In operation, device 100 is installed in tubing string 130
which is runable from surface. In the string, device 100 is in a
position to catch the balls. In a wellbore stimulation operation, a
suitable tubing string may be referred to as a frac string. In a
wellbore stimulation operation, a liner 150 may be set in the well
122. The stimulation of the formation 148 accessed by the wellbore
may occur through the liner. The liner may be set by use of a liner
hanger 154, liner packers 156, etc. and has an inner diameter 158
accessible through an uphole end. In this embodiment, liner 150
includes a plurality of fluid ports 160, included in tubular
components commonly called frac ports 162, through which fluid can
communicate between the annular area 164 about the liner and the
liner inner diameter 158. The frac ports include valves controlling
the open/closed position of the fluid ports. The valves are opened
by and fluids are diverted through ports 160 by use of actuation
balls 115a, 115b sized to land and seal in correspondingly sized
seats. As described in the above-noted US patents, the balls can be
graduated in size. A smallest ball 115a, for example, is used to
actuate the lowest component in the liner, since that ball can pass
through all the seats intended for larger balls before landing in
its suitably sized seat.
[0044] The frac string is typically latchable at its distal end
130a onto the upper end 150a of the liner and, when desired, may be
disconnected to be pulled to surface. The distal end can include a
connecting point such as an on/off tool or a seal assembly.
[0045] Device 100 may be installed adjacent, for example, at or
near, distal end 130a.
[0046] If the frac string in which device 100 is installed is to be
used also during the stimulation operation, the protrusions 116 may
initially be held in a retracted position (FIG. 3A), such that they
do not affect the passage of balls 115a, 115b downwardly therepast.
In one embodiment, the protrusions are configurable into a position
that presents substantially no restriction in the string. For
example, device 100 may include an activation mechanism 134,
according to one of the embodiments described herein before.
Activation mechanism 134 allows protrusions 116 to be initially
retracted (FIG. 3A) and therefore inactive, and to be released into
an active, ball catching position (FIG. 3B-3D) when it is
appropriate.
[0047] For example, as noted above, the illustrated embodiment
includes openable sleeve 136, which holds the protrusions in a
retracted, inactive position. In particular, openable sleeve 136
extends partially or fully across an annular recess in which the
protrusions are retracted when the string is run in to hold the
protrusions in the recess. Thus, as far as the pressure containment
is concerned, that string can have substantially full pressure
containment and substantially no restrictions through inner
diameter 132.
[0048] Device 100 is run in as part of the frac string 130. After
connecting the frac string to liner 150, a stimulation job may be
pumped through string 130 including conveying balls 115a, 115b,
which can pass through the inactive ball catcher device, with
protrusions 116 retracted.
[0049] After the job is run, before flow back is initiated, the
device may be activated to position protrusions 116 into their
blocking position such that the protrusions are available to catch
balls 115a, 115b.
[0050] While the device may be activated in numerous possible ways,
openable sleeve 136 in this embodiment, is moved to release the
protrusions by engagement with a ball passing downwardly thereby.
Ball 140 may be dropped and conveyed with fluid pressure arrow P
toward sleeve 136 (FIG. 3A) and eventually lands in sleeve 136. The
pressure differential generated when ball 140 lands in the seat of
sleeve 136 causes the sleeve to shear loose and move to release
protrusions 116, which pop out into the active, blocking position
(FIG. 3B).
[0051] In the illustrated embodiment, ball 140 is launched only for
the purpose of actuating the ball catcher. Ball 140 remains in the
seat until flow back is initiated.
[0052] Once activated, protrusions 116 are in an active, blocking
position which means balls can flow through in one direction only,
that being toward surface. Back flow can then be initiated. While
normally after a stimulation process, the frac string is pulled out
of the well in order to put the well on production, frac string in
this case is left in place to accept back flowing fluid and to
allow balls carried by the back flowing fluid to pass through bore
132 and reach device 100. With consideration as to the
characteristics of the well, device 100 is in a position to be
reached and passed through upwardly by ball 140 and at least some
of balls 115a, 115b, as they are pushed along by back flow.
However, once they pass the protrusions upwardly, the balls cannot
reverse direction and go back down because of the protrusions 116
(FIG. 3C).
[0053] When at least some, and in this embodiment all, of the balls
are above the protrusions of device 100, frac string 130 can be
disconnected from the liner and pulled to surface (FIG. 3D). To
pull the frac string out of the hole, the disconnect mechanism,
such as on/off tool or seal assembly, is operated and then the frac
string is pulled out of the hole (arrow POOH). Balls 140, 115a,
115b remain retained in the string above the protrusions and are,
therefore, also retrieved to surface.
[0054] Since all the balls that passed upwardly through the
protrusions are captured by ball catching device 100, the balls
will also be removed from the well. As such, a ball-free liner 150
and well 122 is available if further operations are needed.
[0055] The well can be shut in before the frac string 150 is
disconnected, if desired.
[0056] The protrusions are sized to retain the balls used in the
well. For example, the protrusions may be selected with
consideration as to the smallest balls to be retained, such that
when the protrusions come together in the blocking position, any
gaps therebetween are smaller than the smallest ball to be
retained. The smallest ball may be the last one flowing back and
may, therefore, be the ball directly above the protrusions.
[0057] In one embodiment, the protrusions may be formed and/or
spaced in their housing such that fluid is mostly directed through
one opening, as this will facilitate pushing balls up through the
protrusions. To block flow except through a smaller opening, less
than the full inner diameter, the protrusions can be closely
positioned, overlapping, etc. For example, in one embodiment,
protrusions 116 can be closely positioned adjacent their bases to
block fluid flow adjacent inner wall 112c, while an opening remains
between tips 116a.
[0058] If the ball catcher tends to retain liquid when retrieved to
surface, a bypass port may be provided to permit fluid to escape
from above protrusions, and more likely balls, to prevent the
development of a wet string. If the ball catcher is, as shown in
FIGS. 2 and 3, formed in a tubing string, the bypass port may be
normally closed but openable when desired. For example, with
reference to FIG. 4, ball catching device 200 may be incorporated
in a tubing string 230, which requires a pressure holding wall
above, in and below device 200.
[0059] Ball catcher device 200 includes a main housing 212 with an
inner open area 214 and one or more protrusions 216 in the inner
open area moveably connected to the main housing 212. The one or
more protrusions are configured via their moveable connection to
allow balls 240a, 240b, 240c to move upwardly therethrough in a
direction toward surface and to block any reverse movement of those
balls downwardly therepast.
[0060] Inner open area 214 is sized to accommodate the balls to be
caught by device 200. If the size of the balls relative to ID of
open area 214 is such that liquid cannot readily drain, arrows D,
from area 214 down past the balls, a wet string may develop.
[0061] Housing 212 therefore can include a bypass port 260 that is
an opening for fluid evacuation between inner area 214 and the
outer surface 212d of the housing. Bypass port 260 has a closure
262 that permits the port to be opened with intent. Closure 262 is
a sleeve in this embodiment, shiftable by hydraulic manipulation.
For example, to open the bypass, a ball 264 may be launched from
surface and is selected to apply a force to the closure to drive it
open. In this embodiment, closure 262 includes a seat 262a onto
which ball 264 can land FIG. 4B and generate a pressure to shift
the closure down FIG. 4C. Once port 260 is open, liquid above the
balls can drain out, arrows D'. The string, device and caught balls
240a, 240b, 240c and ball 264 can be pulled up without the
inconvenience of a wet string.
[0062] Another embodiment of a ball catcher is shown in FIGS. 5 and
6. In this embodiment, ball catcher 300 is connected to bridge plug
assembly 370 for installation in a well 322. Bridge plug assembly
370 includes a plurality of slips 372 and a seal 374 that can be
engaged against the wall of the well. Bridge plug assembly 370 can
be connected to a string 320 for manipulation including running in,
setting and retrieval. Of course, the tool can be conveyed downhole
by other means, as noted above.
[0063] Ball catcher device 300 includes a main housing 312 with an
inner open area 314 and a protrusion 316 in the inner open area
pivotally connected to the main housing 312. In this embodiment,
the protrusion is in the form of a flapper and is configured via a
pivotal connection 344 to be moveable up away from its seat 376 to
allow a ball 340 to move upwardly therethrough in a direction
toward surface. As shown in FIG. 6B, protrusion 316 is also
configured, as by biasing, to pivot back down onto its seat 376
after the ball pushes past to block any reverse movement of that
ball downwardly therepast.
[0064] The protrusion includes apertures 378 for fluid passage
therethrough.
[0065] Inner open area 314 is sized to accommodate at least one
ball to be caught by device 300.
[0066] Because the ball catching device can be installed after any
wellbore operations to convey actuation balls 340, the protrusion
of the device is always in the active position and does not have a
mechanism for inactivation thereof.
[0067] In use, the tool including bridge plug assembly 370 and ball
catching device 300 is run into a well and installed by setting the
bridge plug including setting slips 372 and seal 374 (FIG. 6A). The
tool is then in position to catch balls 340 from a treatment string
350. Seal 374 ensures that all produced fluids pass up through
catcher 300, carrying the balls along with the flow. When balls
enter area 314, they push up past protrusion 216. After each ball
passes, the protrusion is biased back down about connection 344
onto seat 376 to prevent the ball from reversing down past the
protrusion.
[0068] Protrusion 316 doesn't seal off the well, as fluid can
continue to flow through apertures 378, even when the protrusion is
seated.
[0069] When all the balls have been caught, the tool can be
retrieved to surface carrying balls 340 therein (FIG. 6B). In this
embodiment, string 320 is tripped in and connected to the upper end
of the bridge plug. Bridge plug 370 is then manipulated to retract
slips 372 and seal 374 and the string is pulled to pull the tool
toward surface.
[0070] Balls 340 are caught by protrusion 316, but fluid can drain
through apertures 378.
[0071] The previous description of the disclosed embodiments is
provided to enable any person skilled in the art to make or use the
present invention. Various modifications to those embodiments will
be readily apparent to those skilled in the art, and the generic
principles defined herein may be applied to other embodiments
without departing from the spirit or scope of the invention. Thus,
the present invention is not intended to be limited to the
embodiments shown herein, but is to be accorded the full scope
consistent with the claims, wherein reference to an element in the
singular, such as by use of the article "a" or "an" is not intended
to mean "one and only one" unless specifically so stated, but
rather "one or more". All structural and functional equivalents to
the elements of the various embodiments described throughout the
disclosure that are know or later come to be known to those of
ordinary skill in the art are intended to be encompassed by the
elements of the claims. Moreover, nothing disclosed herein is
intended to be dedicated to the public regardless of whether such
disclosure is explicitly recited in the claims. No claim element is
to be construed under the provisions of 35 USC 112, sixth
paragraph, unless the element is expressly recited using the phrase
"means for" or "step for".
* * * * *