Multi-stage well isolation and fracturing

Abstract

An activation tool is provided for use in a well isolation and stimulation string, The activation tool has a stationary seat for receiving a ball deployed down the string, a stationary inner body, a stationary outer body and a moving sleeve positioned between the stationary inner and stationary outer bodies and movable from an open position to a closed position by force of the ball against the seat.

1 . An activation tool for use in a well isolation and stimulation string, said activation tool comprising:
 a. a stationary seat for receiving a ball deployed down the string;   b. a stationary inner body;   c. a stationary outer body; and   d. an internal sleeve positioned between the stationary inner and stationary outer bodies said internal sleeve being shiftable from an open position to a closed position by force of the ball against the seat, said internal sleeve further comprising:
 i. a collet formed with the internal sleeve and shiftable to lock the moving internal sleeve in the closed position, 
   
       wherein the internal sleeve and the collet are shiftable with a single stroke. 
     
     
         2 . The activation tool of  claim 1 , wherein deployment of the ball onto the seat prevents circulation of liner fluid through the activation tool and re-directs fluid into a chamber formed between the stationary inner body and the moving internal sleeve, said fluid acting to move the sleeve. 
     
     
         3 . The activation tool of  claim 2 , further comprising one or more shears screws affixing the stationary inner body to the moving internal sleeve, said shear screws being shearable at a predetermined liner fluid accumulated in the tool when the ball lands on the seat, wherein shearing of said one or more shear screws allows the internal sleeve to shift to the closed position. 
     
     
         4 . A method of closing an activation tool on a stimulation string, said method comprising:
 a. deploying a ball down the stimulation string to the activation tool;   b. receiving the ball on a stationary seat of the activation tool;   c. shifting an internal sleeve being from an open position to a closed position by force of the ball against the seat; and   d. shifting a collet integrally connected to the internal sleeve to lock the internal sleeve in the closed position,   
       wherein the internal sleeve and the collet are shifted in a single stroke.