Ball injecting apparatus for wellbore operations

Abstract

Apparatus is provided injecting drop balls into a wellbore, such as for actuating downhole tools. A ball magazine adapted for storing drop balls, in two or more transverse ball chambers, is axially movable in a magazine housing mounted at a transverse port to a fluid passage in fluid communication with the wellbore. The magazine is serially actuable for aligning a first and subsequent chambers with the transverse port for injecting stored balls to the wellbore. An indicator, such as a rod extending from the magazine housing, can be used to indicate the relative location of the chamber and transverse port. The apparatus can be used in a system and methodology for actuating two or more downhole tools spaced at intervals along the wellbore.

1 . A ball injecting apparatus for injecting drop balls into a wellbore comprising:
 a magazine housing having an axial bore formed therethrough and a transverse port, the transverse port being adapted for fluidly connecting to the wellbore;   a magazine axially movable in the axial bore, the magazine having two or more transverse chambers spaced axially therealong, each chamber being adapted for receiving an individual drop ball therein; and   an actuator for axially positioning the magazine within the axial bore between a loaded position where none of the two or more chambers are axially aligned with the transverse port, and an injection position where one selected chamber of the two or more chambers is moved into alignment with the transverse port wherein a drop ball for the selected chamber is injected from the selected chamber and through the transverse port to the wellbore.   
   
   
       2 . The ball injecting apparatus of  claim 1  wherein each chamber is a transverse, substantially cylindrical bore through the magazine which is parallel and axially spaced from each other chamber. 
   
   
       3 . The ball injecting apparatus of  claim 2  wherein the magazine is rotationally constrained for maintaining rotational alignment of the selected chamber with the transverse port. 
   
   
       4 . The ball injecting apparatus of  claim 3  further comprising rotational alignment means for rotationally aligning the magazine and the magazine housing. 
   
   
       5 . The ball injecting apparatus of  claim 4  wherein the rotational alignment means is a co-operating key and keyway between the magazine housing and the magazine. 
   
   
       6 . The ball injecting apparatus of  claim 4  wherein the rotational alignment means is a co-operating key and keyway on the actuator. 
   
   
       7 . The ball injecting apparatus of  claim 1  further comprising:
 an indicator rod extending from an end of the magazine opposite to the actuator, the indicator rod extending axially through the housing; and   an indicator seal between the housing and the indicator rod.   
   
   
       8 . The ball injecting apparatus of  claim 1  further comprising an indicator for signaling the position of the selected chamber. 
   
   
       9 . The ball injecting apparatus of  claim 8  wherein the indicator is an electronic sensor for sensing relative position of the magazine with respect to the housing. 
   
   
       10 . The ball injecting apparatus of  claim 8  wherein the indicator comprises:
 an indicator rod extending from an end of the magazine opposite to the actuator, the indicator rod extending axially through the magazine housing;   an indicator seal between the housing and the indicator rod;   an indicator disc at a distal end of the indicator rod;   an indicator housing extending about the indicator rod and fixed relative to the magazine housing;   a plurality of holes bored through the housing each of which is axial spaced at intervals to correspond to the axial spacing of the two or more chambers in the magazine; and   removable stop pins for positioning in the plurality of holes along the indicator housing and acting between the indicator disc and the indicator housing for engaging the indicator disc thereagainst for signaling when one of the one or more chambers is aligned with the transverse port.   
   
   
       11 . The ball injecting apparatus of  claim 10  wherein the pins are shear pins acting between the indicator disc and the indicator housing, the actuator being actuatable to cause one of the shear pins to shear and permit movement of the magazine to a subsequent shear pin to axially align the selected chamber with the transverse port. 
   
   
       12 . The ball injecting apparatus of  claim 1  wherein the two or more chambers are similarly sized. 
   
   
       13 . The ball injecting apparatus of  claim 1  wherein each chamber is axially and equally spaced from each other chamber. 
   
   
       14 . The ball injecting apparatus of  claim 1  wherein the actuator comprises a double-acting hydraulic ram having a piston in a cylinder, the piston being operatively connected to the magazine. 
   
   
       15 . The ball injecting apparatus of  claim 14  wherein the piston is connected to magazine by a piston rod. 
   
   
       16 . The ball injecting apparatus of  claim 15  further comprising a piston rod seal between the magazine housing and the piston rod wherein the wellbore is isolated from the actuator. 
   
   
       17 . A method for injecting drop balls into a flow passage comprising:
 providing a ball injecting apparatus having
 a magazine housing having an axial bore formed therethrough and a transverse port, the transverse port being adapted for fluidly connecting to the wellbore; 
 a magazine axially movable in the axial bore, the magazine having two or more transverse chambers spaced axially therealong, a first of the two or more of the chambers having a first drop ball loaded therein and each subsequent chamber having a subsequent drop ball loaded therein; and 
 an actuator for axially positioning the magazine within the axial bore between a loaded position where none of the two or more chambers are axially aligned with the transverse port, and an injection position where one selected chamber of the two or more chambers is moved into alignment with the transverse port; 
   mounting the ball injecting apparatus so that the transverse port is fluidly connected to the flow passage;   actuating the actuator to move the magazine in the magazine housing to axially align the first chamber with the transverse port for injecting the first drop ball from the first chamber and through the transverse port to the flow passage; and   serially repeating the actuating step for each subsequent chamber for serially injecting each of the subsequent drop balls from the subsequent chambers.   
   
   
       18 . The method of  claim 17  wherein the mounting step comprising mounting the ball injecting apparatus to a top of a wellbore for forming the flow passage extending downward from the transverse port to the wellbore, wherein the selected ball is injected to the flow passage by gravity. 
   
   
       19 . The method of  claim 17  wherein the mounting step comprises mounting the ball injecting apparatus intermediate a fluid flow line connected to the wellbore for forming the flow passage through transverse port of the ball injecting apparatus, wherein the selected ball is injected to the flow passage by fluid passing through the fluid flow line and the transverse port and to the wellbore. 
   
   
       20 . A system for injecting one or more balls into a wellbore for actuating a series of downhole tools comprising:
 a ball injecting apparatus having
 a magazine housing having an axial bore formed therethrough and a transverse port, the transverse port being adapted for fluidly connecting to the wellbore; 
 a magazine axially movable in the axial bore, the magazine having two or more transverse chambers spaced axially therealong, a first of the two or more of the chambers having a first drop ball loaded therein and each subsequent chamber having a subsequent drop ball loaded therein; and 
 an actuator for axially positioning the magazine within the axial bore between a loaded position where none of the two or more chambers are axially aligned with the transverse port, and an injection position where one selected chamber of the two or more chambers is moved into alignment with the transverse port; 
   two or more downhole tools spaced at intervals along the wellbore, the two or more downhole tools comprising a first downhole tool actuable upon receipt of the first drop ball and each subsequent downhole tool actuable upon receipt of each subsequent drop ball;   wherein when the actuator is actuated to move the magazine in the magazine housing to axially align the first chamber with the transverse port, the first drop ball is injected from the first chamber and through the transverse port to the wellbore for actuating the first downhole tool; and   serially actuating the actuator for each subsequent chamber for serially injecting each of the subsequent drop balls from the subsequent chambers to serially actuate each of the subsequent downhole tools.   
   
   
       21 . The system of  claim 20  wherein
 the two of more downhole tools are a first and subsequent packers for isolating a first zone and subsequent zones along the wellbore and the first packer is actuable upon receipt of the first drop ball for blocking the wellbore below the packer, and each subsequent packer is actuable upon receipt of the subsequent drop ball for blocking the wellbore below the subsequent packer;   the subsequent drop ball has a diameter greater than the first drop ball and each subsequent ball has a diameter greater than an immediately preceding subsequent drop ball wherein each of the drop balls does not actuate the subsequent packer.   
   
   
       22 . The method of  claim 21  further comprising:
 a wellhead fluidly connected to the wellbore, wherein the ball injecting apparatus is mounted to a top of the wellhead for forming a flow passage extending downward from the transverse port to the wellbore, wherein the selected ball is injected to the flow passage by gravity.   
   
   
       23 . The method of  claim 21  further comprising:
 a wellhead fluidly connected to the wellbore; and   a fluid flow line for flowing fluid to the wellhead, wherein the ball injecting apparatus is mounted intermediate the fluid flow line forming a flow passage through transverse port of the ball injecting apparatus and to the wellbore, wherein the selected ball is injected to the flow passage by fluid passing through the fluid flow line and the transverse port and to the wellbore.   
   
   
       24 . The system of  claim 23  wherein the wellhead further comprises a wellhead isolation tool having a bore of sufficient size to accept the first and subsequent drop balls.