1. Field of Invention
The invention is directed to ball launching assemblies for releasing balls into wellbores to facilitate completion operations in oil and gas wells and, in particular to surface-located ball launching assemblies capable of launching multiple balls in sequence.
2. Description of Art
Use of balls and ball seats in completion operations are generally known in the art. For example, typical ball seats are tubular members having a bore or passageway that is restricted by a seat. A ball or drop plug is disposed on the seat, preventing or restricting fluid from flowing through the bore of the ball seat and, thus, isolating the tubing or conduit section in which the ball seat is disposed. As the fluid pressure above the ball or drop plug builds up, the conduit can be pressurized for tubing testing or actuating a tool connected to the ball seat such as setting a packer. Ball seats are also used in cased hole completions, liner hangers, flow diverters, frac systems, and flow control equipment and systems.
Although the terms “ball seat” and “ball” are used herein, it is to be understood that a drop plug or other shaped plugging device or element may be used with any ball seats capable of receiving a ball to perform the required completion operation. For simplicity it is to be understood that the term “ball” includes and encompasses all shapes and sizes of plugs, balls, or drop plugs unless the specific shape or design of the “ball” is expressly discussed.
In certain completion operations, it is desired to drop or launch multiple balls into the wellbore so that more than one completion operation can be performed. For example, a first ball may be dropped or launched into the wellbore to set a packer. Thereafter, second, third, fourth, etc. balls may be dropped or launched into the wellbore to set an additional packer, set a bridge plug, set an anchor, run fracturing operations, or any other well completion operation. Multiple ball launch assemblies, thus, are designed to launch multiple balls into wellbores.
Broadly, the ball launch assemblies disclosed herein are surface-located ball launch assemblies that comprise multiple ball launch pods disposed around an outer wall surface of a housing and operatively associated with a flow tube or sleeve disposed within the housing. An actuator assembly operatively associated with the flow tube rotates the flow tube causing multiple balls to be launched in sequence into the wellbore. The actuator may be hydraulically or pneumatically actuated. In specific embodiments, one or more of the ball launch pods comprise a biased member that forces the ball against an outer wall surface of the flow tube until the flow tube is rotated such that a ball opening in the flow tube corresponding to the ball launch pod is placed in alignment with the ball launch pod. After alignment of the opening in the flow tube with the ball launch pod, the biased member forces the ball through the ball opening and into a bore of the flow tube that is in fluid communication with the wellbore. The ball is, thus, dropped or launched into the wellbore so that it can perform its designed downhole function.
In other specific embodiments, the multiple openings in the flow tube are all the same size so that multiple balls of the same diameter or shape can be sequentially launched. In other embodiments, the multiple openings in the flow tube are different sizes so that multiple balls of differing diameters or shape can be sequentially launched. In one particular embodiment, the openings are spirally disposed along the longitudinal length of the flow tube.
In one specific embodiment, the actuator assembly comprises a pneumatically actuated piston operatively associated with an incremental drive assembly such as a ratchet gear. Upon pressure being applied, the piston rotates the ratchet gear which in-turn rotates the flow tube. The ratchet gear is calibrated so that one application of pressure rotates the flow tube once and each of the openings in the flow tube are calibrated so that upon each actuation of the piston and, thus, ratchet gear, one opening is aligned with one ball launch pod, but the remaining openings in the flow tube are not in alignment with the other ball launch pods, or at least not in alignment with other ball launch pods that have not yet launched their respective balls.
In particular embodiments, the ball launch pods include an indictor capable of visually showing when a ball has been launched from the ball launch pod.
While the invention will be described in connection with the preferred embodiments, it will be understood that it is not intended to limit the invention to that embodiment. On the contrary, it is intended to cover all alternatives, modifications, and equivalents, as may be included within the spirit and scope of the invention as defined by the appended claims.
Referring now to
Multiple ball launch assembly 20 may also include flush line inlet 30 so that fluid can be pumped into, or out of, multiple ball launch assembly 20 as desired or necessary for the operation of multiple ball launch assembly 20.
Actuator assembly 40 is disposed at upper end 24. Although actuator assembly 40 may be any device known to persons skilled in the art, in the embodiment of
As best illustrated in
Housing cap 53 is releasably secured to upper end 24 of housing 22 such as through threads (not shown) or any other fastener member. Housing cap 53 and dowel pin 61 secure inner top cap 59 to housing 22. Piston bracket 44 is secured to inner top cap 59 by fasteners (not shown) such as bolts.
Flow tube 54 comprises one or more flush line openings 32 to permit fluids to flow into and out of flush line inlet 30. Flow tube 54 also comprises a plurality of ball openings 34 to permit the passage of a plurality of corresponding sized balls (not shown) from a plurality of corresponding ball launch pods. As shown in the embodiment of
In the embodiment shown in
In the particular embodiment shown, incremental drive member 66 comprises ratchet assembly 70. As illustrated in
Referring now to
Cam 90 is disposed in cam housing 81 and is operatively associated with indicator shaft 87 such that actuation of cam 90 causes indicator shaft 87 to rotate which, in turn, moves indicator 84 from the pre-launched position (
Cam 90 may be in direct contact with ball 100 in the non-launched position. Alternatively, as shown in
In operation, multiple ball launch assembly 20 is assembled such that flow tube 54 is initially oriented to block all of the openings 99 of ball launch pods 80. Multiple ball launch assembly 20 is then connected at the surface a wellbore by connecting lower end 26 to wellbore casing or tubing (not shown) and actuator assembly 40 is placed in connection with an actuator control unit, such as pneumatic or hydraulic controls.
After installation of multiple ball launch assembly 20, actuator assembly 40 is actuated which rotates drive assembly 50 to rotate flow tube 54. In so doing a first ball opening 34 in flow tube 54 is aligned with a first opening 99 of a first ball launch pod 80. As a result, a first ball 100 is launched from the first ball launch pod 80, through the first opening 99, through the first ball opening 34, into the bore of flow tube 54, and, thus, into the wellbore. Thereafter, actuator assembly 40 actuated to align a second ball opening 34 with a second opening 99 of a second ball launch pod 80. As a result, a second ball is launched from the second ball launch pod 80, through the second opening 99, through the second ball opening 34, into the bore of flow tube 54, and, thus, into the wellbore. The foregoing steps can be repeated until all of the balls are launched from the multiple ball launch assembly 20.
As discussed briefly above, when each of the first, second, third, etc., ball openings 34 of flow tube are aligned with each corresponding first, second, third, etc., openings 99 of ball launch pods 80, the corresponding ball 100 can be launched into the wellbore due to one or more of gravity acting on the ball, the release energy stored in a biased member which is transferred directly to the ball or indirectly to the ball through one or more of ball plunger 92 and/or cam plunger 94, and/or by camming action caused by the lowering of a weighted indicator which rotates a cam to push the ball, either directly or indirectly, out of openings 99.
It is to be understood that the invention is not limited to the exact details of construction, operation, exact materials, or embodiments shown and described, as modifications and equivalents will be apparent to one skilled in the art. For example, one or more of biased member 96, ball plunger 94, or cam plunger 92 is not required in ball launch pods 80. Moreover, ball launch pods 80 may be disposed at a sloping angle relative to housing 22 and flow tube 54 so that gravity assists the launching of ball 100. Additionally, the size of each ball launch pod and, thus, each ball, can vary or they can all be the same size. Further, the actuator assembly does not require a piston and the drive assembly does not require a ratchet assembly. Any other actuator assembly or drive assembly can be included. Moreover, rotation of the flow tube does not have to continually block openings 99 of ball launch pods 80 that have already launched their respective balls. Accordingly, the invention is therefore to be limited only by the scope of the appended claims.
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