Patent Publication Number: US-2013228326-A1

Title: Ball injecting apparatus for wellbore operations with external loading port

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application is a continuation-in-part of U.S. application Ser. No. 13/411,607, filed Mar. 4, 2012, entitled “Ball injecting apparatus for wellbore operations with external loading port”, which claims priority to, and benefit of, U.S. Provisional Application Ser. No. 61/508,590 filed Jul. 15, 2011 and also entitled, “Ball injecting apparatus for wellbore operations with external loading port”, both of which are incorporated by reference herein in their entirety. 
    
    
     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&#39;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 ; 
         FIG. 15  is a sectional view of the embodiment of  FIG. 13 ; 
         FIG. 16   a  is perspective view of yet another embodiment of the invention, having a plurality of ram block receiving housings; 
         FIG. 16   b  is another perspective view of the embodiment of  FIG. 16   a;    
         FIG. 17  is a sectional view of the embodiment of  FIG. 16   a  along line E-E of  FIG. 16   b;    
         FIG. 18   a  is a perspective view of four the of ball housings, with their respective actuators, of the embodiment of  FIG. 16   a;    
         FIG. 18   b  is another perspective view of four the of ball housings, with their respective actuators, of the embodiment of  FIG. 16   a;    
         FIG. 19  is a sectional view of the ball housings of  FIG. 18   a;    
         FIGS. 20   a  and  20   b  are sectional views of one of the ball housings of  FIG. 18   a , showing the ram block in a misaligned position and an aligned position, respectively; 
         FIGS. 21   a  and  21   b  are sectional views of another one of the ball housings of  FIG. 18   a , showing the ram block in a misaligned position and an aligned position, respectively; 
         FIG. 22   a  is another perspective view of the embodiment of  FIG. 16   a , wherein one of the ball housings is in an aligned position; and 
         FIG. 22   b  is another sectional view of the embodiment of  FIG. 16   a , wherein one of the ball housings is in an aligned position and illustrating how the ram block can push a radial bore cap down into a ram block receiving housing against a spring-biased force. 
     
    
    
     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 one or more chambers  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 at least one chamber  40  (for loading, unloading or inspection of balls  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 one or more chambers  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&#39;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&#39;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&#39; 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&#39; 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 at least one 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&#39;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&#39;s, and the ball ram block&#39;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 . 
     Other Embodiment 
     In the embodiment of  FIGS. 16   a - 22   b,  the injector  10  has four radial ball arrays  35 ′,  35 ″, 35 ′″, 35 ″″, with each array  35  having four radial bores  33  located at substantially 90 degrees from each other along the horizontal plane of said array  35 . Each array  35  is comprised of two adjacently-located ball housings  34 , wherein each of the radial bores  33  of the two ball housings  34  are in fluid communication with the axial bore  32 , for selectively making a plurality of balls  12  available to the axial bore  32  via a respective ram block  11 . Preferably, two adjacent bores  33  (within a particular array  35 ) each have a ball housings  34  (e.g. the two ball housings  34   a  in the top array  25 ), while the remaining two bores  33  have a ram block receiving housing  200 . Ram block receiving housing  200  do not feature a ram block and are preferably located opposite a ball housing  34 . 
     All of the ram blocks  11  in this embodiment have a plurality of chambers  40 , each to receive, store and discharge a ball  12 ; thereby allowing a particular ram block  11  to have a plurality of balls  12 . More particularly, in this embodiment the ram blocks  11  of the ball housings  34   a  in the top array  35 ′ each have two chambers  40 , so as to hold two balls each—for a total of four balls in the top array  35 ′. The rest of the ram blocks  11 , of the remaining ball housings  34  each have three chambers  40 , so as to hold three balls  12  each—for a total of six balls in each of the remaining three arrays  35 ; see,  FIG. 17 . This embodiment therefore provides for a total of twenty-two balls across the four arrays  35 ′,  35 ″, 35 ′″, 35 ″″. 
     Because the ram blocks  11  hold a plurality of balls, such ram blocks  11  may extend across bore  32  when placed in the aligned position OA for each of the chambers  40  in such block  11 . As such, preferably, the bores  33  associated with a ball housing  34  are oriented (along the horizontal plane of an array  35 ) at 180 degrees opposite to those bores  33  having a ram block receiving housing  200 . ram block receiving housing  200  and their respective radial bores  33  are of such dimensions that a ram block  11  can be at least partially received by a bore  33  of the corresponding (opposing) ram block receiving housing  200 , i.e. when ram block  11  is in the aligned position OA. See, for example  FIG. 22   b  and the array  35 ′″ that is second from the bottom. 
     Each ram block receiving housing  200  preferably comprises a spring-biased radial bore cap  120  provided at the end of the radial bore  33  that is proximal to the axial bore  32 . Radial bore cap  120  is normally biased by spring  124  within radial bore  33  of ram block receiving housing  200  (as generally shown in  FIGS. 17 and 22   b ). 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 receiving housing  200  when biased outward, so that radial bore cap  120  aligns substantially with the wall of axial bore  32  when an opposing ram block  11  is retracted within its radial bore  33  into the misaligned position MP. In another embodiment (not shown), the ram receiving housing  200  may simply comprise a radial bore  33  of sufficient length so as to receive a ram block  11  therein. 
     Like the embodiment of  FIGS. 6   a - 12   b , each ball housing  34  is associated with an actuator  14 . Actuators  14  are suitable for aligning a ball  12  (held within a particular chambers  40  of the relevant ram block  11 ) 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 aligned position OA and the misaligned position MP, said alignments being now relative to a particular chamber  40  within the multi-chambered ram block  11 . 
     The embodiment of  FIGS. 16   a - 22   b  illustrates a variety of suitable actuators  14   a,    14   b,    14   c  to achieve proper alignment of a particular chamber  40  (within the multi-chambered ram block  11 ) with the axial bore  32  when in the aligned position OA; and to achieve proper misalignment of the ram block  11  (back within its radial bore  33 ; and aligning with the port  50 ) when ram block  11  is put in the misaligned position MP. For example, actuator  14   a  is a telescoping actuator featuring an internal hydraulic telescoping mechanism  14   i,  as more clearly shown in  FIGS. 20   a  and  20   b . Actuator  14   c,  in contrast, features an external telescoping mechanism  14   e  (see  FIG. 17 , for example). 
     Advantageously, telescoping actuator mechanisms  14   i,    14   e  give discrete positions which allows for easy placement of a particular chamber  40  into the aligned position OA during operations. For example, a telescoping actuator mechanism  14   i  that is 2-stage provides two discrete positions and will be suitable for aligning the chambers  40  of a two-chambered ram block  11  into the aligned position OA in a serial, step-wise fashion (see, for example the two-stage internal hydraulic telescoping mechanism shown in  FIGS. 20   a  and  20   b ). Similarly, a 3-stage telescoping actuator mechanism  14  provides three discrete positions and will be suitable for aligning the chambers  40  of a three-chambered ram block  11  into the aligned position OA during operations (see, for example the three-stage internal hydraulic telescoping mechanism of the bottom array  35  as shown in  FIGS. 17 and 19 ). 
     Hydraulic telescoping actuator mechanisms  14   i,    14   e  are known. For example, TRD Manufacturing, Inc. of Machesney Park, Ill. distributes such telescoping actuators under the trademark SERIES ‘TC’™. 
     Another suitable actuator  14  is a conventional double-acting hydraulic ram  60  (having a piston  61  in a cylinder  62  operatively connected to the ball ram block  11  through a piston rod  63 ), such as actuator  14   b  and wherein the position of said conventional actuator  14   b  is monitored via a position sensor  250 . See, for example  FIGS. 21   a  and  21   b . Electronic position sensors for hydraulic cylinders are known; for example, Energy Manufacturing Company, Inc. headquartered in Monticello, Iowa can currently provide such electronic position sensor units, which are also referred to as electro-hydraulic control, or “smart” cylinders. 
     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  33  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. However, and as shown in the embodiment of  FIGS. 16   a - 22   b , each ram block  11  can hold a plurality of balls  12  and, as such, the total number of balls (twenty-two in the case of that embodiment) exceeds the number of radial bores  33  (sixteen in the case of that embodiment) and the number of ball housing  34  (eight in the case of that embodiment). 
     At the appropriate times and as operations dictate, each ball ram block  11  (or each chamber  40  within a multi-chambered 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 ; 
     alternatively an electronic position sensor  250  may be utilized to confirm such alignment; yet further alternatively, the discrete operation of a telescoping actuator may be utilized to confirm such alignment. 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 ram block  11  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 appropriate misaligned position MP and then loading said subsequent balls  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 any chambers  40 , such as to ensure that a ball  12  has left its particular 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.