US20130014936A1

US20130014936A1 - Ball injecting apparatus for wellbore operations with external loading port

Info

Publication number: US20130014936A1
Application number: US13/411,607
Authority: US
Inventors: Sheldon GRIFFITH
Original assignee: Individual
Current assignee: Individual
Priority date: 2011-07-15
Filing date: 2012-03-04
Publication date: 2013-01-17
Also published as: CA2746598A1

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.

Description

CROSS REFERENCE TO RELATED APPLICATION

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

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

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.
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.
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.
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.
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).
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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 1¼″ 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.
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

Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, wherein:

FIG. 1 a is perspective view of an embodiment of the invention;

FIG. 1 b is a side view of the embodiment of FIG. 1 a;

FIG. 2 a is a sectional view of the embodiment of FIG. 1 a along line A-A of FIG. 1 b;

FIG. 2 b is an enlarged view of the circled area B in FIG. 2 a;

FIG. 3 a is perspective view of another embodiment of the invention;

FIG. 3 b is a side view of the embodiment of FIG. 3 a;

FIG. 4 a is a sectional view of one of the radial ball arrays of the embodiment of FIG. 3 a;

FIG. 4 b is a side view, with a partial sectional view, of one of the radial ball arrays of the embodiment of FIG. 3 a;

FIG. 4 c is an enlarged view of the circled area C in FIG. 4 b;

FIGS. 5 a-5 c are various perspective views of an embodiment of a ball ram block;

FIG. 6 a is perspective view of yet another embodiment of the invention;

FIG. 6 b is a side view of the embodiment of FIG. 6 a;

FIG. 6 c is a side view, partially schematic, of the embodiment of FIG. 6 a supported on a wellhead structure on a wellhead;

FIG. 7 a is a top end view of the embodiment of FIG. 6 a;

FIG. 7 b is a side view of one of the ball housings with actuator and indicator system of the embodiment of FIG. 6 a;

FIG. 7 c is a sectional view of the ball housing with actuator and indicator system of the embodiment of FIG. 6 a along line D-D of FIG. 7 b;

FIG. 8 a is a sectioned perspective view of the embodiment of FIG. 6 a;

FIG. 8 b is a perspective view of the ball housing with actuator and indicator system of the embodiment of FIG. 6 a, illustrating the ball ram block in an extended, aligned position and illustrating the radial bore cap in a compressed position;

FIGS. 9 a-9 g are perspective views of the embodiment of a ball ram block and radial bore cap of the embodiment of FIG. 6 a and illustrating the radial bore cap in both compressed and extended positions;

FIGS. 10 a-10 c are sectioned perspective views of the ball housing with actuator, ram block and indicator system of the embodiment of FIG. 6 a, illustrating the ball ram block in an extended, aligned position and illustrating the radial bore cap in a compressed position;

FIGS. 11 a-11 c are sectioned perspective views of the ball housing with actuator, ram block and indicator system of the embodiment of FIG. 6 a, illustrating the ball ram block in a retracted, misaligned position and illustrating the radial bore cap in an extended position;

FIG. 12 a is a perspective view of the ball ram block of FIGS. 9 a-9 g, but not showing the radial bore cap;

FIG. 12 b is a sectioned perspective view of the ball ram block of FIGS. 9 a-9 g, also illustrating a piston rod attached to the ram block and showing the radial bore cap in an extended position;

FIG. 13 is perspective view of yet another embodiment of the invention;

FIG. 14 is a side view of the embodiment of FIG. 13; and

FIG. 15 is a sectional view of the embodiment of FIG. 13.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

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.
With reference to the Figures, and generally in accordance with a preferred embodiment of the invention as shown in FIGS. 6 a-12 b, 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 20 b 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 20 b (see FIG. 6 c). Preferably, the injector 10 is fit with a top access port 10 p and an access valve 10 v, such as a T-valve.
The wellhead structure 20 can include a high pressure wellhead or a frac head and a wellhead valve 20 v 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 20 b, flow passage P is fluidly connected to the wellbore 20 b 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 20 b 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.
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 20 b 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 20 b (see, for example, FIGS. 2 a-2 b, 8 a, 10 a-10 c and 11 a-11 c). In a preferred embodiment, axial bore 32 has a diameter of 7 and 1/16 inches.
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. 1 a-12 b 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.
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.
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 20 b. For example, see FIGS. 2 a-2 b, 8 a and 15.
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 20 b.
The ball ram block 11 comprises a piston-like linearly-extending body 11 b having at least one chamber 40 to receive, store and discharge an individual ball 12. Body 11 b has at least constraining end walls 40 c, 40 d 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 11 b, for forming entrance and exit openings 40 a, 40 b to permit ball 12 to be loaded into the chamber 40 or released therefrom. More preferably, entrance and exit openings 40 a, 40 b 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.
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 20 b 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.
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).
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 50 p through the ball housing 34, said passage 50 p 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 50 d, 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.
Preferably, external port 50 is selectively sealable by using a closing member 52 that is removably, sealably secured at distal end 50 d. More preferably, closing member 52 comprises a plug 52 p sealably secured at distal end 50 d by means of a quick release union such as a hammer union assembly 52 h, thereby permitting easy access to the passage 50 p, 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.
In the embodiment of FIGS. 1 a-2 b, the external port 50 is located within a lateral extension 34 l of the ball housing 34 and the axis of its passage 50 p 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. 3 a-4 c, 6 a-12 b and 13-15, the external port 50 is likewise located within a lateral extension 34 l of the ball housing 34, but its passage 50 p 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. 6 b, 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.
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 52 p 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).
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. 6 a-6 b 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.
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 20 b. 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. 8 a, 8 b and 10 a-10 c, as well as in the embodiments of FIGS. 2 a-2 b 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 20 b. As shown in FIGS. 7 b-7 c, 8 a and 11 a-11 c, as well as in the embodiments of FIGS. 2 a-2 b 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.
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. 7 c. 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 20 b 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.
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 20 b 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.
As shown in FIGS. 10 a-11 c 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 34 e 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.
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. 6 a-12 b, 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. 7 c.
In a preferred embodiment, and as more clearly shown in FIGS. 9 a-9 g, the ram block 11 is provided with a radial bore cap 120 at the end 11 e of the ram block 11 that is proximal to the axial bore 32. More preferably, radial bore cap 120 is housed within a cavity 11 c of the ram block 11 at proximal end 11 e. Even more preferably, radial bore cap 120 is biased outward, in a normally expanded state, by a spring 124 placed within cavity 11 c and a second cavity 126 that is within the radial bore cap 120 (see FIGS. 7 c, 8 a, 9 f-9 g 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. 8 a 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.
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 20 b. 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.
Operation
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.
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 20 b 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. 6 a-12 b, 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.
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 20 b. 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 20 b 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.
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 20 v and then bleeding off the pressure through top access port 10 p and access valve 10 v), 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.
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 20 b, such quick means to obtain a visual view into the chamber 40 can provide additional confirmation of such release or of an unsuccessful attempt.
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.

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:

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

20. The ball housing with actuator assembly of claim 19, wherein the external port further comprises: