Stage cementing tool and method

Abstract

A stage cementing tool for wellbore cementing, the stage cementing tool including a side pocket conduit and opening and closing pistons in the conduit. An actuator extends from the closing piston to an inner diameter of the stage cementing tool through a passage in the tool wall. The actuator has a contact surface actuatable from within the inner diameter to cause the closing piston to move into the closing position.

1 . A stage cementing tool for wellbore cementing, the stage cementing tool comprising:
 a cylindrical body with a cylindrical wall encircling an inner diameter and ends configured for coupling to a casing string;   a first lateral port through the cylindrical wall;   a second lateral passage through the cylindrical wall adjacent the first lateral port;   a conduit extending outside the inner diameter of the cylindrical wall and including an open end opening to the outer surface, the conduit positioned such that the first lateral port and the second lateral passage open into the conduit;   an opening piston in the conduit in a sealing position positioned to seal against fluid flow from the first lateral port to the open end, the opening piston being configured to be movable from the sealing position to an open position permitting fluid flow from the first lateral port to the open end;   a closing piston in the conduit, the closing piston being moveable into a closing position to seal against fluid flow out the open end of the conduit; and   an actuator extending from the closing piston to the inner diameter through the second lateral passage, the actuator having a contact surface actuatable from within the inner diameter to cause the closing piston to move into the closing position.   
     
     
         2 . The stage cementing tool of  claim 1 , further comprising a sliding sleeve in the inner diameter configured to apply force to the contact surface of the actuator when the sliding sleeve is moved. 
     
     
         3 . The stage cementing tool of  claim 2  wherein the actuator is engaged with the sliding sleeve to restrict rotation of the sliding sleeve within the inner diameter. 
     
     
         4 . The stage cementing tool of  claim 2  further comprising a shearable connection between the sliding sleeve and the cylindrical body and the actuator is engaged for movement with the sliding sleeve. 
     
     
         5 . The stage cementing tool of  claim 1  wherein the closing piston moves along a path and the actuator extends laterally relative to the path. 
     
     
         6 . The stage cementing tool of  claim 1  wherein the closing piston moves along a path that is at an angle relative to a long axis of the inner diameter and the actuator is at an end of the closing piston. 
     
     
         7 . The stage cementing tool of  claim 1 , wherein the opening piston is moveable by hydraulic pressure from the sealing position to an open position and in the open position, the opening piston is expelled out of the conduit. 
     
     
         8 . The stage cementing tool of  claim 7 , further comprising a coupling connecting the opening piston to the closing piston and wherein the coupling has a selected break force, and the opening piston is moveable when the hydraulic pressure exceeds the break force and decouples the opening piston from the closing piston. 
     
     
         9 . The stage cementing tool of  claim 1 , wherein the conduit includes an erosion resistant coating. 
     
     
         10 . A method for cementing an annulus of a wellbore, the method comprising:
 applying hydraulic pressure to a cementing tool according to  claim 1  that is within the wellbore, the hydraulic pressure moving the opening piston from the sealing position to the open position;   pumping cement through the first lateral port and the conduit into the annulus; and   applying a force from within the inner diameter against the contact surface of the actuator, thereby causing the closing piston to move into the closing position.   
     
     
         11 . The method of  claim 10  wherein applying the force includes launching a plug to move into the inner diameter and apply force directly or indirectly against the contact surface. 
     
     
         12 . The method of  claim 11  further comprising landing the plug in a shiftable sleeve in the inner diameter, shifting the shiftable sleeve to move the shiftable sleeve against the contact surface. 
     
     
         13 . The method of  claim 12  further comprising drilling out the shiftable sleeve, while rotation of the shiftable sleeve is prevented by engagement with the actuator.