Downhole catcher for an actuating ball and method

Abstract

A ball catching device has been invented that catches an actuator ball used in a wellbore to actuate a downhole tool. The device catches the ball downhole as it begins to flow back with fluids toward surface. The device is configured such that when a ball flows back with wellbore fluids, the ball can flow through the device and if the ball reverses direction, as by falling back due to decreased or stopped production back flow, then the device will catch the ball and keep it from falling back past the device into the well.

1 . A downhole ball catcher for preventing an actuation ball migrating upwardly through a well from falling back down deeper into the well after passing upwardly through the downhole ball catcher, the downhole ball catcher comprising:
 a main housing sized to be positioned downhole in the well and including a bottom end, a top end, an inner open area and openings for fluid flow from the bottom end, through the inner open area and out through the top end; and   a protrusion connected by a moveable connection to the main housing and positioned in the inner open area in a blocking position to block passage of a ball through the inner open area, the moveable connection being configured to allow movement of the protrusion away from the blocking position in response to a ball pushing upwardly past the protrusion toward the top end and the moveable connection being configured to resist movement of the protrusion away from the blocking position to prevent movement of the ball downwardly past the protrusion toward the bottom end.   
     
     
         2 . The downhole ball catcher of  claim 1  wherein the moveable connection includes at least one of a pivot, a flexing member or a slider/groove. 
     
     
         3 . The downhole ball catcher of  claim 1  wherein the moveable connection is resilient biasing the protrusion to the blocking position. 
     
     
         4 . The downhole ball catcher of  claim 1  further comprising a fishing structure for accepting engagement of a retrieval tool. 
     
     
         5 . The downhole ball catcher of  claim 1  further comprising a connection to a retrieval tool. 
     
     
         6 . The downhole ball catcher of  claim 1  wherein the top end is open and sized to allow the ball to pass. 
     
     
         7 . The downhole ball catcher of  claim 1  formed as a separate structure and independently positionable in the well. 
     
     
         8 . The downhole ball catcher of  claim 1  wherein the main housing is installed as part of a tubing string with the inner open area open to the tubing string's inner bore. 
     
     
         9 . The downhole ball catcher of  claim 8  wherein the tubing string is a frac string through which wellbore stimulation fluids are injected into the well. 
     
     
         10 . The downhole ball catcher of  claim 8  wherein the bottom end is formed for accepting connection to a lower portion of the string and the top end is formed for accepting connection of an upper portion of the string. 
     
     
         11 . The downhole ball catcher of  claim 1  further comprising an activation mechanism for maintaining the protrusion in an inactive position and operable to move the protrusion into an active position. 
     
     
         12 . The downhole ball catcher of  claim 11 , wherein the activation mechanism an openable sleeve behind which the protrusion are retracted when in the inactive position. 
     
     
         13 . The downhole ball catcher of  claim 12  wherein openable sleeve is moveable by sliding to release the protrusion to assume the active position. 
     
     
         14 . The downhole ball catcher of  claim 12  wherein the openable sleeve includes a seat on its inner diameter sized to catch and create a seal with a ball such that pressure can be built up behind the ball sufficient to shift the sleeve to release the protrusion. 
     
     
         15 . A wellbore assembly comprising:
 an actuator ball in the well useful to actuate a downhole tool and moveable to migrate upwardly in the well as driven by back flow of wellbore fluids; and   an actuator ball catching device positioned in a lower portion of the well above the actuator ball, the device including a main housing with a fluid flow passage from a bottom end to an upper end and formed to be removable from the well by pulling to surface and the device having a mechanism to allow the passage of an actuator ball moving up through the device, the mechanism preventing the actuator ball from moving down past the device into the well.   
     
     
         16 . The wellbore assembly of  claim 15  wherein the mechanism includes a plurality of protrusions acting as a one-way valve for the actuator ball to allow movement of the actuator ball in an upward direction, while preventing movement of the actuator ball downward through the actuator ball catching device. 
     
     
         17 . The wellbore assembly of  claim 15  wherein the mechanism includes a protrusion connected by a moveable connection to the main housing and positioned in the inner open area in a blocking position to block passage of a ball through the inner open area, the moveable connection configured to allow movement of the protrusion away from the blocking position to allow movement of the actuator ball upwardly past the protrusion toward the top end and the moveable connection configured to resist movement of the at least one protrusion away from the blocking position to allow movement of the actuator ball downwardly past the protrusion toward the bottom end. 
     
     
         18 . The wellbore assembly of  claim 15  wherein the moveable connection includes at least one of a pivot, a flexing member or a slider/groove. 
     
     
         19 . The wellbore assembly of  claim 15  wherein the moveable connection is resilient biasing the protrusion to the blocking position. 
     
     
         20 . The wellbore assembly of  claim 15  further comprising a fishing structure for accepting engagement of a retrieval tool. 
     
     
         21 . The wellbore assembly of  claim 15  further comprising a connection to a retrieval tool. 
     
     
         22 . The wellbore assembly of  claim 15  wherein the top end is open and sized to allow the ball to pass. 
     
     
         23 . The wellbore assembly of  claim 15  formed as a separate structure and independently positionable in the well. 
     
     
         24 . The wellbore assembly of  claim 15  wherein the main housing is installed as part of a tubing string with the inner open area open to the tubing string's inner bore. 
     
     
         25 . The wellbore assembly of  claim 24  wherein the tubing string is a frac string through which wellbore stimulation fluids are injected into the well. 
     
     
         26 . The wellbore assembly of  claim 24  wherein the bottom end is formed for accepting connection to a lower portion of the string and the top end is formed for accepting connection of an upper portion of the string. 
     
     
         27 . The wellbore assembly of  claim 15  further comprising an activation mechanism for maintaining the protrusion in an inactive position and operable to move the protrusion into an active position. 
     
     
         28 . The wellbore assembly of  claim 27 , wherein the activation mechanism an openable sleeve behind which the protrusion are retracted when in the inactive position. 
     
     
         29 . The wellbore assembly of  claim 28  wherein openable sleeve is moveable by sliding to release the protrusion to assume the active position. 
     
     
         30 . The wellbore assembly of  claim 28  wherein the openable sleeve includes a seat on its inner diameter sized to catch and create a seal with a ball such that pressure can be built up behind the ball sufficient to shift the sleeve to release the protrusion. 
     
     
         31 . A method for catching an actuation ball from a wellbore, the method comprising:
 positioning an actuator ball catching device downhole in a wellbore; back flowing wellbore fluids to push an actuator ball along the wellbore to the actuator ball catching device; catching the actuator ball by allowing the actuator ball to move up through the actuator ball catching device, the actuator ball catching device catching the actuator ball by preventing the actuator ball from falling back down into the well; and retrieving the actuator ball catching device to surface along with the actuator ball caught in the actuator ball catching device.   
     
     
         32 . The method of  claim 31  wherein the actuator ball catching device includes a protrusion acting as a one-way valve for the actuator ball and wherein during catching the actuator ball passes upwardly through the plurality of protrusions and thereafter cannot pass downwardly through the protrusions. 
     
     
         33 . The method of  claim 31  wherein positioning includes dropping the actuator ball catching device into the wellbore or running the actuator ball catching device into the wellbore using a string. 
     
     
         34 . The method of  claim 31  wherein positioning places the actuator ball catching device low down in the wellbore. 
     
     
         35 . The method of  claim 31  wherein the wellbore includes a liner installed therein and positioning places the actuator ball catching device adjacent the upper end of the liner. 
     
     
         36 . The method of  claim 35 , wherein catching occurs uphole of the liner. 
     
     
         37 . The method of  claim 31  further comprising launching the actuator ball after positioning. 
     
     
         38 . The method of  claim 31  further comprising launching the actuator ball before positioning. 
     
     
         39 . The method of  claim 31  wherein retrieving uses a string or a pressure driven seal. 
     
     
         40 . The method of  claim 31  further comprising activating the actuator ball catching device after positioning. 
     
     
         41 . The method of  claim 31  wherein during positioning the actuator ball catching device is in an inactive condition and after positioning the method further comprises launching the actuator ball and activating the actuator ball catching device. 
     
     
         42 . The method of  claim 31  further comprising opening a drain port and allowing the fluid to drain from above the actuator ball caught in the actuator ball catching device.