U.S. patent application number 13/411607 was filed with the patent office on 2013-01-17 for ball injecting apparatus for wellbore operations with external loading port.
The applicant listed for this patent is Sheldon GRIFFITH. Invention is credited to Sheldon GRIFFITH.
Application Number | 20130014936 13/411607 |
Document ID | / |
Family ID | 47518261 |
Filed Date | 2013-01-17 |
United States Patent
Application |
20130014936 |
Kind Code |
A1 |
GRIFFITH; Sheldon |
January 17, 2013 |
BALL INJECTING APPARATUS FOR WELLBORE OPERATIONS WITH EXTERNAL
LOADING PORT
Abstract
A ball injecting apparatus for releasing balls into a well
comprises a housing adapted to be supported by a wellhead
structure, the housing having an axial bore therethrough, said
axial bore being in fluid communication and aligned with the
wellbore, at least one ball housing having a radial bore extending
away from the axial bore, a ball ram block movable along the radial
bore and having a chamber for storing a ball therein or for
releasing a ball therefrom, an actuator for moving the ball ram
block along the radial bore and an external port on the ball
housing for providing access to the ball ram block and the
chamber.
Inventors: |
GRIFFITH; Sheldon; (Red
Deer, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
GRIFFITH; Sheldon |
Red Deer |
|
CA |
|
|
Family ID: |
47518261 |
Appl. No.: |
13/411607 |
Filed: |
March 4, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61508590 |
Jul 15, 2011 |
|
|
|
Current U.S.
Class: |
166/75.15 |
Current CPC
Class: |
E21B 33/068
20130101 |
Class at
Publication: |
166/75.15 |
International
Class: |
E21B 33/13 20060101
E21B033/13 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 15, 2011 |
CA |
2746598 |
Claims
1. A ball injecting apparatus for releasing balls into a well
having a wellhead structure and wellbore comprising: a main housing
adapted to be supported by the wellhead structure, the main housing
having an axial bore therethrough, said axial bore being in fluid
communication and aligned with the wellbore; at least one ball
housing having a radial bore extending radially away from the axial
bore and in fluid communication therewith; for each ball housing, a
ball ram block movable along the radial bore, the ball ram block
having a chamber for storing a ball therein or releasing a ball
therefrom; for each ram block, an actuator for moving the ball ram
block along the radial bore for operably aligning said ball ram
block with the axial bore for releasing any stored ball therein
into said axial bore and operably misaligning said ball ram block
from the axial bore for clearing the axial bore; and an external
port on said ball housing for providing access to the ball ram
block and the chamber.
2. The ball injecting apparatus of claim 1, wherein the external
port further comprises: a passage through the ball housing to guide
a ball into the chamber when said ram ball block is in a misaligned
position; and means to selectively seal the external port so as to
retain fluid pressure in the ball housing or so as to provide
access to the chamber.
3. The ball injecting apparatus of claim 2, wherein the external
port has a distal end and the means to selectively seal the
external port comprises a closing member that is removably,
sealably secured at said distal end.
4. The ball injecting apparatus of claim 3, wherein the closing
member comprises a plug sealably secured at the distal end by means
of a quick release union.
5. The ball injecting apparatus of claim 4, wherein the quick
release union is a hammer union.
6. The ball injecting apparatus of claim 2, wherein the passage is
oriented substantially parallel to the axial bore.
7. The ball injecting apparatus of claim 2, wherein the passage is
oriented at an angle anywhere between 10 to 80 degrees up from the
horizontal plane.
8. The ball injecting apparatus of claim 2, wherein the passage is
oriented at an angle approximately 40 degrees up from the
horizontal plane.
9. The ball injecting apparatus of claims 1 to 8, wherein the
chamber comprises entrance and exit openings of sufficient
dimensions to provide sufficient clearance to a ball to allow said
ball to enter or exit easily through either of said entrance or
exit opening.
10. The ball injecting apparatus of claims 1 to 9, further
comprising an indicator system to provide confirmation of alignment
of the ball ram block with the axial bore.
11. The ball injecting apparatus of claim 10 wherein the indicator
system further comprises: an indicator housing having an indicator
viewing window; and an indicator rod moveable within said indicator
housing and viewable through said indicator viewing windows;
wherein the indicator rod is operably connected to the
actuator.
12. The ball injecting apparatus of claims 1 to 11, wherein the ram
ball block further comprises a radial bore cap biased outward so as
to align substantially with the wall of axial bore when the ram
block is retracted within the radial bore into a misaligned
position.
13. The ball injecting apparatus of claims 1 to 12, wherein the ram
ball block further comprises rotational alignment means to prevent
rotation of the ram block 11 relative to the ball housing.
14. The ball injecting apparatus of claims 1 to 13, comprising a
plurality of ball housings arranged into at least one radial ball
array.
15. The ball injecting apparatus of claim 14, wherein the plurality
of ball housings comprise three radial ball arrays stacked
vertically on top of one another, each array having four ball
housings, each with their respective radial bores oriented at 90
degrees from one another.
16. The ball injecting apparatus of claim 14, wherein the plurality
of ball housings comprise two radial ball arrays stacked vertically
on top of one another, each array having four ball housings, each
with their respective radial bores oriented at 90 degrees from one
another.
17. A ball injecting apparatus for releasing balls into a well
having a wellhead structure and wellbore comprising: a main housing
adapted to be supported by the wellhead structure, the main housing
having an axial bore therethrough, said axial bore being in fluid
communication and aligned with the wellbore; at least one ball
housing having a radial bore extending radially away from the axial
bore and in fluid communication therewith; for each ball housing, a
ball ram block movable along the radial bore, the ball ram block
having a chamber for storing a ball therein or releasing a ball
therefrom; and for each ram block, an actuator for moving the ball
ram block along the radial bore for operably aligning said ball ram
block with the axial bore for releasing any stored ball therein
into said axial bore and operably misaligning said ball ram block
from the axial bore for clearing the axial bore; wherein the
chamber comprises entrance and exit openings of sufficient
dimensions to provide sufficient clearance to a ball to allow said
ball to enter or exit easily through either of said entrance or
exit opening.
18. The ball injecting apparatus of claim 17, wherein the ram ball
block further comprises a radial bore cap biased outward so as to
align substantially with the wall of axial bore when the ram block
is retracted within the radial bore into a misaligned position.
19. A ball housing with actuator assembly for use with a ball
injecting apparatus, said ball injecting apparatus for releasing
balls into a well having a wellhead structure and wellbore and
having a main housing adapted to be supported by the wellhead
structure, the main housing having an axial bore therethrough, said
axial bore being in fluid communication and aligned with the
wellbore, the ball housing assembly comprising: a radial bore
extending radially away from the axial bore and in fluid
communication therewith; a ball ram block movable along the radial
bore, the ball ram block having a chamber for storing a ball
therein or releasing a ball therefrom; an actuator for moving the
ball ram block along the radial bore for operably aligning said
ball ram block with the axial bore for releasing any stored ball
therein into said axial bore and operably misaligning said ball ram
block from the axial bore for clearing the axial bore; and an
external port on said ball housing for providing access to the ball
ram block and the chamber.
20. The ball housing with actuator assembly of claim 19, wherein
the external port further comprises: a passage through the ball
housing to guide a ball into the chamber when said ram ball block
is in a misaligned position; and means to selectively seal the
external port so as to retain fluid pressure in the ball housing or
so as to provide access to the chamber.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application is a regular application of U.S.
Provisional Patent Application Ser. No. 61/508,590 filed Jul. 15,
2011 and entitled, "BALL INJECTING APPARATUS FOR WELLBORE
OPERATIONS WITH EXTERNAL LOADING PORT", the entirety of which is
incorporated herein by reference.
FIELD OF THE INVENTION
[0002] The present invention relates to an apparatus that houses,
and controls the release of, down-hole actuating devices for oil
and gas wells. More particularly, the apparatus comprises one or
more external loading ports to introduce or inject actuating
devices into the apparatus and provides positive identification as
to whether a particular actuating device was successfully injected
into the wellbore.
BACKGROUND OF THE INVENTION
[0003] Down-hole actuating devices serve various purposes.
Down-hole actuating devices such as balls, darts, etc. may be
released into a wellhead to actuate various down-hole systems.
[0004] For example, in an oil well fracturing (also known as
"fracing") or other stimulation procedures the down-hole actuating
devices are a series of increasingly larger balls that cooperate
with a series of packers inserted into the wellbore, each of the
packers located at intervals suitable for isolating one zone of
interest (or intervals within a zone) from an adjacent zone.
Isolated zone are created by selectively engaging one or more of
the packers by releasing the different sized balls at predetermined
times. These balls typically range in diameter from a smallest
ball, suitable to block the most downhole packer, to the largest
diameter, suitable for blocking the most uphole packer.
[0005] At surface, the wellbore is normally fit with a wellhead
including valves and a pipeline connection block, such as a
frachead, which provides fluid connections for introducing
stimulation fluids, including sand, gels and acid treatments, into
the wellbore.
[0006] Conventionally, operators introduce balls to the wellbore
through an auxiliary line, coupled through a valve, to the
wellhead. This auxiliary line would be fit with a valved tee or
T-configuration connecting the wellhead to a fluid pumping source
and to a ball introduction valve. One such conventional apparatus
is that as set forth in U.S. Pat. No. 4,132,243 to Kuus. There,
same-sized balls are used for sealing perforations and these are
fed, one by one, from a stack of identically sized balls held in a
magazine.
[0007] However, the apparatus appears limited to using
identically-sized balls in the magazine stack during a particular
operation. To accommodate a set of balls of a different size,
however, the apparatus of Kuus requires disassembly, substitution
of various components (such as the magazine, ejector and ejector
sleeve, which are properly sized for the new set of balls) and then
reassembly. The apparatus of Kuus, therefore, cannot accommodate
different sized balls during a particular operation, since it is
designed to handle only a plurality of same-sized sealer balls at
any one time. To use a plurality of different sized balls, in the
magazine, will result in jamming of the devices (such as in the
ejector sleeve area).
[0008] Moreover, the ball retainer springs in Kuus do not appear to
be very durable and would also need to be replaced when using a
ball of a significantly different size. There is a further concern
that the ball retainer springs could also break or come loss and
then enter into the wellbore (which is undesirable). Additionally,
there is no positive identification whether a ball was successfully
indexed or ejected from the stack of balls for injection.
[0009] Furthermore, the device of Kuus is oriented so as to have
the sealer balls transferred into the magazine by gravity and must
therefore utilize a fluid flow line and valved tee through which
well treating fluid and sealer balls are subsequently pumped into a
wellbore. The device of Kuus, with its peculiar orientations of
components, could therefore not be directly aligned with, or
supported by, a wellhead.
[0010] More recent advance in ball injecting apparatus do feature a
housing adapted to be supported by the wellhead. Typically the
housing has an axial bore therethrough and is in fluid
communication and aligned with the wellbore. This direct aligned
connection to the wellhead avoids the conventional manner of
introduce balls to the wellbore through an auxiliary fluid flow
line (which is then subsequently connected to the wellhead) and the
disadvantages associated therewith. Some of these disadvantages,
associated with conventional T-connected ball injectors, include
requiring personnel to work in close proximity to the treatment
lines through which fluid and balls are pumped at high pressures
and rates (which is hazardous), having valves malfunctioning and
balls becoming stuck and not being pumped downhole and being
limited to smaller diameter balls. In particular, larger packer
balls also require specialty large bore launchers and related 4''
and even 5'' piping which is costly, may not have the required
pressure ratings or, if so, be heavy and bulky.
[0011] Examples of more recent ball injecting apparatus, which are
supported by the wellhead, and are aligned with the wellbore,
include those described in published U.S. Patent Application
2008/0223587, published on Sep. 18, 2008 and published U.S. Patent
Application 2010/0288496, published on Nov. 18, 2010, the entirety
of both published applications being incorporated by reference
herein. Another example of a ball injecting apparatus supported by
the wellhead and aligned with the wellbore is published U.S. Patent
Application 2010/0294511, published on Nov. 25, 2010, the entirety
of which is also incorporated by reference herein. Although these
devices address many of the above issues identified with injection
balls indirectly into the wellbore, i.e. via fluid flow lines,
these still retain a significant number of disadvantages.
[0012] For example, it is know that the device taught in published
U.S. Patent Application 2010/0294511, where each ball is
temporarily supported by a rod or finger within the main bore.
However, the pumping of displacement fluid through unit can damage
or scar balls, especially if the displacement fluid is sand-laden
fracturing fluid or if the balls are caused to rapidly spin on the
support rod or finger. Such damaged balls typically fail to then
properly actuate a downhole packer and fully isolate the intended
zone. This then requires an operator to drop an identical ball down
the bore which is extremely inefficient, time consuming, costly and
can adversely compromise the well treatment.
[0013] The apparatus described in published U.S. Patent Application
2008/0223587, published on Sep. 18, 2008 teaches a ball magazine
adapted for storing balls, in two or more transverse ball chambers,
axially movable in a transverse port and which can be serially
actuated for serially injecting the stored balls from the magazine
into the wellbore. This overcomes a number of the disadvantages of
the device taught in published U.S. Patent Application
2010/0294511. However, the invention contemplates loading the
magazine externally from the ball injecting apparatus and, since
the transverse chambers are transverse, cylindrical passageways or
bores through the magazine's body with both horizontal and vertical
openings, the plurality of balls can easily fall out of their
respective chambers during preloading operations (i.e. through
either entrance or exit openings). This could result in runaway
balls on the surface next to the wellhead and potentially create a
safety hazard. The design of this devices therefore makes the
loading of the magazine difficult and time consuming, especially
when loading a magazine with a large number of balls that must be
monitored (i.e. to prevent the balls from exiting out through their
respective entrance or exit openings) until placed within the axial
bore of the apparatus.
[0014] Moreover, because the balls are serially positioned in a
linear extending magazine, the ball injector of this patent
application becomes cumbersome and unwieldy, especially when
designed to work with 10, 12 or even 24 balls. For all practical
purposes, the apparatus of this application is therefore limited to
handling 5, or maybe 6, balls before becoming ungainly and
unmanageable. As such, the applicant in a subsequent patent
application, stated that this (earlier) apparatus retains a measure
of mechanical complexity.
[0015] Published U.S. Patent Application 2010/0288496, published on
Nov. 18, 2010, teaches a radial ball injection apparatus comprising
a housing adapted to be supported by the wellhead. The housing has
an axial bore therethrough and at least one radial ball array
having two or more radial bores extending radially away from the
axial bore and in fluid communication therewith, the axial bore
being in fluid communication and aligned with the wellbore. Each
radial bore has a ball cartridge for storing a ball and an actuator
for moving the ball cartridge along the radial bore. The actuator
reciprocates the ball cartridge for operably aligning with the
axial bore for releasing the stored ball and operably misaligning
from the axial bore for clearing the axial bore. This patent
application also teaches that several of the radial ball arrays can
be arranged vertically within one housing, or one or more of the
radial ball arrays can be housed in a single housing and vertically
by stacked one on top of another for increasing the number of
available balls. For example, in one embodiment, it describes using
an injector having two vertically spaced arrays of four radial
bores so as to drop eight (8) ball.
[0016] However, published U.S. Patent Application 2010/0288496
suffers from a number of disadvantages including icing issues
during winter operations which can result in the balls being frozen
within their respective ball cartridges which have a cup-like body
comprised of an open side, a lateral restraining structure and a
supporting side for seating the ball during loading. However,
during winter operations, the balls can become frozen within this
cup-like body, thereby preventing proper release of the balls
downhole. For that reason, U.S. Patent Application 2010/0288496
teaches that one should use methanol in the displacement fluid to
reduce such icing issues. However, using methanol adds to the
expense and complexity of the ball injection process.
[0017] Moreover, and although U.S. Patent Application 2010/0288496
teaches an indicator for indicating a relative position of the ball
cartridge between the aligned and misaligned positions, this
indicator does not indicate whether a ball was actually released
from the cup-like structure, when placed in the aligned position,
or whether it remains stuck and frozen within the ball cartridge,
only to be retracted back into the radial bore when returned to the
misaligned position. Therefore an operator of this apparatus cannot
accurately determine whether a ball was successfully released from
the injector as taught in this patent application.
[0018] A further disadvantage of the apparatus taught by U.S.
Patent Application 2010/0288496 is that each of the balls are
loaded through the axial bore of the injector by rotating the ball
cartridge into a receiving position and then aligning each ball
cartridge with the axial bore so as to be able receive a ball from
above as it is dropped through the axial bore. This results in a
time consuming an awkward loading procedure wherein balls are
loaded serially, one after another, with each ball cartridge then
being stroked between misaligned, aligned and then misaligned
position. In an alternate loading procedure, this application
suggest to pre-load the apparatus by removing the ball cartridges
from each housing, seating the balls into each ball cartridge, and
then reinstalling the loaded ball cartridges on each radial
housing. This alternate loading procedure is also time consuming
and awkward.
[0019] Additionally, in the primary suggested loading procedure,
the balls will need to be carefully aligned along the axial bore
and above its particular ball cartridge before being dropped, so as
to avoid missing the ball cartridge and then having the ball
continue on downward the axial bore. If a dropped ball does miss
the intended ball cartridge and continues downward the axial bore
then, in a best case scenario such as during pre-loading, the ball
exits at the bottom end of the injector to be simply retrieved and
loading can then be attempted again. However, if a dropped ball
misses the intended ball cartridge when the injector is mounted to
the wellhead structure or above a gate valve, then the injector
will have to be disconnected from the wellhead or gate valve so as
to then retrieve the ball. In a worst case scenario, a ball that is
dropped in the axial bore and which misses the ball cartridge could
prematurely be launched down the wellbore and premature activate
one or more downhole tools (such as packers), resulting a ruined
fracturing operation. As such the application even teaches use of a
calibrated tubular or sleeve to assist with the loading of the
balls through the axial bore. This additional piece of equipment
adds further complication to the apparatus and loading
procedure.
[0020] Another prior art apparatus that utilizes a housing having
an axial bore therethrough and a radial ball array having two
radial bores extending radially away from the axial bore and in
fluid communication therewith, the axial bore being in fluid
communication and aligned with the wellbore, is that taught by U.S.
Pat. No. 5,960,881 to Allamon et al. However, this apparatus is
only designed to drop two balls (preferably sized at 11/4'' for the
smaller ball and a 1.75'' for the larger ball) along with a drill
pipe wiper dart and therefore is unsuitable to drop more than two
balls, such as 8 to 12 balls. Additionally, this apparatus relies
on elastomer members having specifically sized circular openings to
allow release of different sized balls when they are urged into the
axial bore by a rod and piston. This elastomer member is subject to
wearing down. Moreover, the different sized circular openings in
the elastomer, along with the need to utilize a centering member to
properly locate the smaller ball within the radial bores, makes
this apparatus complex and impractical for a multi-size and
multi-ball application.
[0021] As such, there remains a need for a safe, simple and
efficient apparatus and mechanism for loading balls therein and for
subsequent introducing into a wellbore.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] Embodiments of the invention will now be described, by way
of example only, with reference to the accompanying drawings,
wherein:
[0023] FIG. 1a is perspective view of an embodiment of the
invention;
[0024] FIG. 1 b is a side view of the embodiment of FIG. 1a;
[0025] FIG. 2a is a sectional view of the embodiment of FIG. 1a
along line A-A of FIG. 1b;
[0026] FIG. 2b is an enlarged view of the circled area B in FIG.
2a;
[0027] FIG. 3a is perspective view of another embodiment of the
invention;
[0028] FIG. 3b is a side view of the embodiment of FIG. 3a;
[0029] FIG. 4a is a sectional view of one of the radial ball arrays
of the embodiment of FIG. 3a;
[0030] FIG. 4b is a side view, with a partial sectional view, of
one of the radial ball arrays of the embodiment of FIG. 3a;
[0031] FIG. 4c is an enlarged view of the circled area C in FIG.
4b;
[0032] FIGS. 5a-5c are various perspective views of an embodiment
of a ball ram block;
[0033] FIG. 6a is perspective view of yet another embodiment of the
invention;
[0034] FIG. 6b is a side view of the embodiment of FIG. 6a;
[0035] FIG. 6c is a side view, partially schematic, of the
embodiment of FIG. 6a supported on a wellhead structure on a
wellhead;
[0036] FIG. 7a is a top end view of the embodiment of FIG. 6a;
[0037] FIG. 7b is a side view of one of the ball housings with
actuator and indicator system of the embodiment of FIG. 6a;
[0038] FIG. 7c is a sectional view of the ball housing with
actuator and indicator system of the embodiment of FIG. 6a along
line D-D of FIG. 7b;
[0039] FIG. 8a is a sectioned perspective view of the embodiment of
FIG. 6a;
[0040] FIG. 8b is a perspective view of the ball housing with
actuator and indicator system of the embodiment of FIG. 6a,
illustrating the ball ram block in an extended, aligned position
and illustrating the radial bore cap in a compressed position;
[0041] FIGS. 9a-9g are perspective views of the embodiment of a
ball ram block and radial bore cap of the embodiment of FIG. 6a and
illustrating the radial bore cap in both compressed and extended
positions;
[0042] FIGS. 10a-10c are sectioned perspective views of the ball
housing with actuator, ram block and indicator system of the
embodiment of FIG. 6a, illustrating the ball ram block in an
extended, aligned position and illustrating the radial bore cap in
a compressed position;
[0043] FIGS. 11a-11c are sectioned perspective views of the ball
housing with actuator, ram block and indicator system of the
embodiment of FIG. 6a, illustrating the ball ram block in a
retracted, misaligned position and illustrating the radial bore cap
in an extended position;
[0044] FIG. 12a is a perspective view of the ball ram block of
FIGS. 9a-9g, but not showing the radial bore cap;
[0045] FIG. 12b is a sectioned perspective view of the ball ram
block of FIGS. 9a-9g, also illustrating a piston rod attached to
the ram block and showing the radial bore cap in an extended
position;
[0046] FIG. 13 is perspective view of yet another embodiment of the
invention;
[0047] FIG. 14 is a side view of the embodiment of FIG. 13; and
[0048] FIG. 15 is a sectional view of the embodiment of FIG.
13.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0049] The following description is of a preferred embodiment by
way of example only and without limitation to the combination of
features necessary for carrying the invention into effect.
Reference is to be had to the Figures in which identical reference
numbers identify similar components. The drawing figures are not
necessarily to scale and certain features are shown in schematic or
diagrammatic form in the interest of clarity and conciseness.
[0050] With reference to the Figures, and generally in accordance
with a preferred embodiment of the invention as shown in FIGS.
6a-12b, the ball injecting apparatus or injector 10 receives and
releases balls 12, including drop balls, frac balls, packer balls,
and the like, down a wellbore 20b to, for example, isolate zones of
interest during wellbore operations such as fracturing. The
injector 10 is preferably supported on a wellhead structure 20
connected to the wellbore 20b (see FIG. 6c). Preferably, the
injector 10 is fit with a top access port 10p and an access valve
10v, such as a T-valve.
[0051] The wellhead structure 20 can include a high pressure
wellhead or a frac head and a wellhead valve 20v having a bore
sufficiently large to permit the passage of the balls 12
therethrough. In the context of fracturing or treating sequential
zones within a formation accessed by the wellbore 20b, flow passage
P is fluidly connected to the wellbore 20b through the wellhead 20.
The wellhead 20 may be connected to pump trucks (not shown) through
a fluid line (not shown) for supplying a fracturing or stimulation
fluid to the wellbore 20b in a conventional manner, such as through
the injecting apparatus 10 or through other ports in the wellhead
20 at a point below the injecting apparatus 10.
[0052] The ball injector 10 comprises a main housing 30 having an
axial bore 32. The axial bore 32 is in fluid communication and
aligned with the wellbore 20b and flow passage P. The ball injector
10 further comprises at least one ball housing 34 having a radial
bore 33 and a ball ram block 11. Ball ram block 11 is adapted to
store a range of diameters of balls, up to the largest ball
required for the particular operation. Ball ram block 11 is
preferably preloaded with said ball 12 and is movable along the
radial bore 33 for aligning the ball 12 with the axial bore 32 and
flow passage P so as to effect injection of said ball 12 into the
wellbore 20b (see, for example, FIGS. 2a-2b, 8a, 10a-10c and
11a-11c). In a preferred embodiment, axial bore 32 has a diameter
of 7 and 1/16 inches.
[0053] Preferably, the ball injector 10 is fit with at least one
radial ball array 35 comprised of two or more ball housings 34,
wherein each of the radial bores 33 of the two or more ball
housings 34 are in fluid communication with the axial bore 32, for
selectively making two or more balls 12 available to the axial bore
32. The embodiments illustrated in FIGS. 1a-12b show a ball
injector 10 comprised of three radial ball arrays 35 stacked
vertically on top of one another, each array 35 having four ball
housings 34, each with radial bores 33 oriented at 90 degrees from
one another (the bores 33 in each array 35 being along the same
horizontal plane), for a total of twelve ball housings 34. The
embodiment illustrated in FIGS. 13-15 shows a ball injector 10
comprised of two radial ball arrays 35 stacked vertically on top of
one another, each array 35 having four ball housings 34, each with
radial bores 33 oriented at 90 degrees from one another (along the
horizontal plane), for a total of eight ball housings 34.
[0054] Advantageously, by placing two, three, four or more ball
housings 34 in the same radial ball array 35, significant height
savings are achieved. More advantageously, a lower profile of the
ball injector 10 allows for easier access to the injector 10 as
well as reduces the strain applied to the entire wellhead 20.
Moment forces imposed on the wellhead can be considerable and thus
a shorter wellhead is stronger and safer.
[0055] Ball ram block 11 maintains ball 12 in the radial bore 33
and may be actuated to reciprocate, extending into and in operable
alignment with the axial bore 32 for releasing a ball 12. Ball ram
block 11 may also be actuated to retract into the radial bore 33
for operable misalignment with the axial bore 32 for clearing the
axial bore 32 and for storing and preventing a ball 12 from being
prematurely released or launched into the wellbore 20b. For
example, see FIGS. 2a-2b, 8a and 15.
[0056] Balls 12 can be injecting directly into the wellhead 20 by
gravity or fluid which urges the balls 12 from the ball ram block
11 (when in operable alignment with axial bore 32) and into the
flow passage P. In many instances, a flow of fluids F is introduced
through flow passage P or other ports in the wellhead to the
wellbore 2 therebelow. By injecting the ball 8 directly into the
flow passage P to join the flow fluid F one avoids accidental
lodging of the ball 8 in side ports or other cavities such as in
some prior art T-configuration injection apparatus. Advantageously,
the ball 12 does not need to change direction and is reliably
introduced into the flow of fluids F through the wellhead 20 for
delivery down the wellbore 20b.
[0057] The ball ram block 11 comprises a piston-like
linearly-extending body 11b having at least one chamber 40 to
receive, store and discharge an individual ball 12. Body 11b has at
least constraining end walls 40c, 40d for forming the chamber 40
and for retaining the ball within the ball ram block 11 during
reciprocating movement along the radial bore 33. Preferably chamber
40 is a transverse, substantially cylindrical passageway or bore
through the body 11b, for forming entrance and exit openings 40a,
40b to permit ball 12 to be loaded into the chamber 40 or released
therefrom. More preferably, entrance and exit openings 40a, 40b are
of sufficient dimensions to provide sufficient clearance to ball 12
so as to allow it to enter or exit easily through either opening
and in either direction.
[0058] When a selected chamber 40 is axially aligned with the axial
bore 32, it is fluidly contiguous with the flow passage P to allow
egress of a ball 12 from the chamber 40 into the wellbore 20b via
axial bore 32 and flow passage P. Preferably, the chamber 40 and
the apparatus 10 itself can be sized to accept a range of diameters
of balls up to the largest ball required for the particular
operation.
[0059] Advantageously, by virtue of transverse chamber 40, ball ram
block 11 does not result in a cup-like structure or cartridge (as
is the case in U.S. Patent Application 2010/0288496) and therefore
does not suffer from the same disadvantages associated with such a
cup-like structure (i.e. balls 12 do not become frozen within ram
block 11 and methanol is not needed to reduce icing issues; since
no icing issues occur with the present invention).
[0060] To provide access to a ram block 11, when the ball ram block
11 is within the radial bore 33, the ball housing 34 and radial
bore 33 are provided with an external port 50. External port 50
comprises a passage 50p through the ball housing 34, said passage
50p being of suitable dimensions to accept a range of diameters of
balls, up to the largest ball required for the particular
operation, and guide such balls 12 into the chamber 40 of a ram
block 11 when said block 11 is in the misaligned position MP. The
external port 50 is selectively sealable at its distal end 50d, so
as to retain fluid pressure in the ball housing 34 (and hence also
axial bore 32 and flow passage P) or so as to provide access to the
chamber 40 (for loading, unloading or inspection of ball 12
therein) as may be desired during operations.
[0061] Preferably, external port 50 is selectively sealable by
using a closing member 52 that is removably, sealably secured at
distal end 50d. More preferably, closing member 52 comprises a plug
52p sealably secured at distal end 50d by means of a quick release
union such as a hammer union assembly 52h, thereby permitting easy
access to the passage 50p, the radial bore 33 and the ball ram
block 11 to remove, load and replace a ball 12 in the chamber 40.
Alternatively the external port 50 may be sealably secured within
the ball housing 34 using other releasable connections. Preferably,
the apparatus 10 is designed to American Petroleum Institute (API)
standards for the particular design criteria including pressure and
fluid characteristics. More preferably, the apparatus 10 is rated
for 10,000 psi.
[0062] In the embodiment of FIGS. 1a-2b, the external port 50 is
located within a lateral extension 34l of the ball housing 34 and
the axis of its passage 50p is oriented substantially along the
vertical axis (and substantially parallel to the axial bore 32). In
this embodiment sufficient space or clearance SP is provided
between adjacent ball housings 34 (which may be overlapping in
their respective radial ball arrays 35) so as to allow for loading
and unloading of balls 12 in all of the ball housings 34 that may
be present in the apparatus 10 (see FIG. 1 b). In the embodiments
of FIGS. 3a-4c, 6a-12b and 13-15, the external port 50 is likewise
located within a lateral extension 34l of the ball housing 34, but
its passage 50p is oriented (along with ball housing 34) at a
slanted angle relative the vertical axis or axial bore 32.
Preferably, this angle is approximately 40 degrees up from the
horizontal plane (see FIG. 6b, angle between lines E and E'). Other
slanted angles (not shown), such as anywhere in the range of 10 to
80 degrees up from the horizontal plane, would likewise work.
[0063] In embodiments where the slanted angles are below the
horizontal plane (not shown), i.e. where the external port's
passage opening faces downward, gravity will tend to pull any ball
12 out of the ram block 11 (and ball housing 34), thereby making
loading or checking of the ball 12 more difficult than when the
slanted angle is above the horizontal plane and gravity assists in
keeping the ball 12 within chamber 40 and radial bore 33. In such
embodiments, reliance will have to be placed on the closing member
52 to maintain the ball 12 in the proper position within the ram
block's chamber 40 and sufficient clearance of the various
components will need to be provided so that actuation of the
apparatus 10 into the aligned position OA does not result in
interference or jamming of some of the apparatus' components (e.g.
plug 52p component of closing member 52 is of sufficient dimension
to still retain ball 12 within the chamber 40, but is not too long
so as to jam the ram block 11 when it is actuated to the aligned
position OA).
[0064] Advantageously, this slanted angle of the external port 50
and ball housing 34 between 10 to 80 degrees up from the horizontal
plane, along with the four radial bores 33 in each array 35 being
oriented at 90 degrees from one another, allows for a closer
spacing SP' of each array 35 to an adjacent array 35 while still
providing sufficient clearance to load, unload and view balls 12
through the external port 50. See, for example, FIGS. 6a-6b and
FIGS. 13-14. More advantageously, a slanted angle of the external
port 50 and ball housing 34, between 10 to 80 degrees up from the
horizontal plane, provides from a more natural and easier viewing
angle to an operator when the apparatus 10 is placed high up on a
wellhead structure 20 and a particular ball housing 34 and ram
block 11 needs to be inspected.
[0065] An actuator 14 is provided to the ball housing 34 for
positioning the ball ram block 11 for aligning a ball 12 (held
within a chamber 40) with the axial bore 32 and flow passage P and
assuring injection of the ball 12 out of a chamber 40 and into the
wellbore 20b. The ball ram block 11 is actuated reciprocally
axially within the radial bore 33 by the actuator 14 between an
operably aligned position OA and an operably misaligned position
MP. As shown in FIGS. 8a, 8b and 10a-10c, as well as in the
embodiments of FIGS. 2a-2b and FIG. 15, when placed in an operably
aligned position OA, the ball ram block 11 is located within the
axial bore 32 for releasing a ball 12 into the wellbore 20b. As
shown in FIGS. 7b-7c, 8a and 11a-11c, as well as in the embodiments
of FIGS. 2a-2b and FIG. 15, when in the misaligned position MP, the
ball ram block 11 is retracted into its respective radial bore 33,
fully clearing the axial bore 32 and either safely housing the ball
12 from accidental release into the axial bore 32 or having empty
chamber 40.
[0066] The ball ram block 11 itself, and the actuation thereof, is
insensitive to the size of the balls. A suitable actuator 14 is a
conventional double-acting hydraulic ram 60 having a piston 61 in a
cylinder 62. See, for example, FIG. 7c. The piston 61 is
operatively connected to the ball ram block 11, such as through a
piston rod 63. A piston rod seal or seals 48 are positioned between
the ball housing 34 and the piston rod 63 wherein the radial bore
33 and wellbore 20b are contained and further are isolated from the
actuator 11. Ports 64 are provided at opposing ends 65, 66 of the
cylinder 62 for connection to a control valve (not illustrated) as
understood by one of skill in the art, and which can be actuated
remotely.
[0067] In embodiments of the invention, rotational alignment means
80 are provided for ensuring that the ball ram block 11, having
chambers 40 formed therein, remains rotationally oriented during
axial manipulation of the ram block 11 for aligning of the chamber
40 with the axial bore 32. While the radial bore 33 in ball housing
34 and ram block 11 can have a cross-sectional profile which
resists rotation, such as a corresponding polygonal profile,
pressure conditions of the wellbore 20b encourage selection of a
generally cylindrical housing 34 and ram block 11. Accordingly,
means 80 are provided for preventing rotation of the ram block 11
relative to the ball housing 34. One of skill in the art would
appreciate that alignment of the ram block 11 within the ball
housing 34 may be accomplished in a number of different ways
including the use of alignment pins, splines, key and keyway
combinations, locking nuts and the like.
[0068] As shown in FIGS. 10a-11c and in the preferred embodiment of
the invention, the ball ram block 11 is aligned within the ball
housing 34, and so as to retain proper alignment of the chamber 40
throughout the axial manipulation of the ball ram block 11, via
alignment pin 82 attached within ball housing 34. As shown, the pin
82 is mounted at end 34e of the interior of the ball housing 34 and
matching keyway or pin chamber 84 is formed in the ball housing 11
for sliding movement along pin 82 when actuated.
[0069] Preferably, an indicator system 100 is provided for
confirmation of alignment of a ball ram block 11 with the axial
bore 32 and flow passage P, in the aligned position OA, so as to
ensure a ball 12 is injected when required. The indicator system
100 may comprise an indicator rod 105 extending from an end 65 of
the actuator 14 opposite the hydraulic ram 60 and connected to
piston 61 for movement therealong with. In the embodiment of FIGS.
6a-12b, the indicator rod 105 extends through an indicator housing
107 which includes indicator viewing windows or openings 108
aligned axially along the housing 107, to allow viewing of the
indicator's position therethrough. Preferably, indicator rod 105 is
painted a bright colour so as to provide a quick and easy visual
cue to allow an operator to determine the indicator's, and the ball
ram block's, relative axial position. Indicator rod seal 110 and
indicator housing seals 111 are provided at the appropriate places
in a conventional manner so as to contain wellbore pressure within
the injector 10 and ball housing 34. See, for example, FIG. 7c.
[0070] In a preferred embodiment, and as more clearly shown in
FIGS. 9a-9g, the ram block 11 is provided with a radial bore cap
120 at the end 11e of the ram block 11 that is proximal to the
axial bore 32. More preferably, radial bore cap 120 is housed
within a cavity 11c of the ram block 11 at proximal end 11e. Even
more preferably, radial bore cap 120 is biased outward, in a
normally expanded state, by a spring 124 placed within cavity 11c
and a second cavity 126 that is within the radial bore cap 120 (see
FIGS. 7c, 8a, 9f-9g and 15). The amount of outward biasing of
radial bore cap 120 relative to the ram block 11 by spring 124 is
pre-set, and the cap 120 is sufficiently retained within the ram
block 11 when biased outward, so that radial bore cap 120 aligns
substantially with the wall of axial bore 32 when the ram block 11
is retracted within the radial bore 33 into the misaligned position
MP (see FIG. 8a for example). One of skill in the art would
appreciate that retaining the bore cap 120 and preventing it from
completely disengaging from the ram block 11 may be accomplished in
a number of different ways including the use of alignment pins,
splines, key and keyway combinations, and the like.
[0071] Advantageously, radial bore cap 120 prevents accidental
lodgment of a ball 12 (that may have been inserted into axial bore
32 by another ball housing 34) within said radial bore 33 and
thereby encourages such ball 12 to instead travel down the axial
bore 32 into the wellbore 20b. More advantageously, should a first
ram block 11 be in the misaligned position MP and a second ram
block 11, located directly opposite the first ram block 11 in the
same radial ball array 35, is then actuated to the aligned position
OA, radial bore caps 120 of both ram blocks 11 will abut and be
placed in a compressed state, thereby allowing the second ram block
11 to partially enter the radial bore 33 of the first ram block 11.
Even more advantageously, the use of such spring-biased radial bore
caps 120 allows for optimal axial bore diameters while still
providing for large radial bore diameters (capable of holding
larger balls 12) and a radial ball array 35 having four ball
housings 34 located at 90 degrees from each other along the
horizontal plane of said array 35.
[0072] Operation
[0073] Preferably, an injector 10 having at least one radial ball
array 35 with two or more radial bores 33, each having an
associated ball housings 34 with an actuator 14, is provided.
However, it is contemplated that an embodiment of the injector 10
comprises only a single radial bore 33 and a single ball housing 34
with an actuator 14 (and therefore no radial array). Multiple ball
12 drops would then be accomplished through repeated reloading of
the chamber 40 through the external port 50 as further described
herein.
[0074] In a preferred embodiment, and during normal fracturing
operations, an injector having said at least one radial ball array
35 is provided wherein the ball ram blocks 11 are normally
positioned in the misaligned position MP within the radial bores
33, each storing a ball 12. Thus, an open and unobstructed axial
bore 32 allows an operator to have unhindered access to the
wellbore 20b during normal wellbore or fracturing operations.
Preferably, there are at least as many radial bores 34 and ball
housings 34 as there are balls 12 required for a particular
wellbore operation. For example, in the embodiment of FIGS. 6a-12b,
the injector 10 has three radial ball arrays 35, each array 35
having four radial bores 33 and corresponding ball housings 34,
providing for a total of twelve balls 12. As another example, the
embodiment of FIGS. 13-15, the injector 10 has two radial ball
arrays 35, each array 35 having four radial bores 33 and
corresponding ball housings 34, providing for a total of eight
balls.
[0075] At the appropriate times and as operations dictate, each
ball ram block 11 is sequentially actuated by actuator 14, one by
one, to the operably aligned position OA for release and injection
into the wellbore 20b. Preferably this alignment is confirmed by
the indicator system 100 for each particular ball ram block 11.
Once in the aligned position OA, the ball 12 will be released from
the chamber 40, under the influence of gravity, into the axial bore
32 and to the wellbore 20b via flow passage P. Alternatively ball
12 can be positively displaced from the chamber 40 by fluid (such
as fracturing fluid) that may be moving through the flow passage
P.
[0076] In situations where a very large number of balls 12 are
required to be dropped, one or more of the chambers 40 in a ball
housing 34 may be reloaded with a subsequent ball 12 via external
port 50. This may be accomplished by isolating the injector 10 from
wellbore pressures (such as by closing wellhead valve 20v and then
bleeding off the pressure through top access port 10p and access
valve 10v), unsealing the external port 50 (such as by removing
closing member 52), ensuring the ram block 11 is actuated to the
misaligned position MP and then loading said subsequent ball 12 via
external port 50. Advantageously, the injector 10 need not be
removed from the wellhead structure 20 in order to reload
balls.
[0077] Likewise, a similar procedure can be used to retract a ram
block 11 into the misaligned position MP, open and unseal the
external port 50 so as to provide an operator with a visual view
into the ram block 11 and chamber 40, such as to ensure that a ball
12 has left its chamber 40. Advantageously, if there was any doubt
about a particular ball 12 having been successfully released into
the wellbore 20b, such quick means to obtain a visual view into the
chamber 40 can provide additional confirmation of such release or
of an unsuccessful attempt.
[0078] Embodiments of the invention are discussed herein in the
context of the actuation of a series of packers within a wellbore
for isolating subsequent zones within the formation for fracturing
of the zones. A series of packers typically use a series of
different sized balls for sequential blocking of adjacent packers.
One of skill in the art however would appreciate that the invention
is applicable to any operation requiring the dropping of one or
more balls (whether same-sized or different sized) into the
wellbore.
* * * * *