Method and apparatus for treating a well

Abstract

A tool for forming an obstruction in the production casing of an oil or gas well includes a sleeve adapted to be secured to the casing and having an annular abutting surface that captures a body or a cage having a solid body within the casing thereby forming an obstruction. The tool may be secured within the well either by an expandable sleeve or a collet having resilient fingers. The tool may be used as a plug to prevent flow through the production casing of the well in a well treatment process such as fracing. A process for treating a well using the tool is also presented.

I claim: 
     
         1 . A tool for forming an obstruction in production casing of an oil or gas well comprising:
 a sleeve adapted to be secured within the production casing;   a cage member having an annular surface adapted to abut against a first end portion of the sleeve; and   the cage member having a solid body that is axially movable to a first position blocking fluid flow through the tool in a first direction and movable to a second position permitting fluid flow through the tool in a direction opposite to the first direction.   
     
     
         2 . The tool according to  claim 1  wherein the cage member includes a hollow cylindrical portion having a diameter slightly less than that of the production casing and a hollow frustoconical portion extending downstream of the hollow cylindrical portion and terminating in an outlet. 
     
     
         3 . The tool according to  claim 1  wherein the cage member further includes a perforated disk closing one end of the hollow cylindrical portion of the cage member. 
     
     
         4 . The tool according to  claim 1  wherein the perforated disk includes an annular wall spacing the solid body from a planar flat portion of the disk. 
     
     
         5 . A tool for forming an obstruction in the production casing of an oil or gas well comprising:
 an expandable sleeve adopted to be secured within the casing.   a solid body having a frustonical shape and having a surface portion adapted to abut against an annular surface on the sleeve thereby forming an obstruction in the well.   
     
     
         6 . A tool for forming an obstruction of an oil or gas well having production casing comprising:
 a sleeve having a passageway therethrough;   a plurality of collet fingers on the sleeve adapted to engage a gap between adjacent production casing members; and   a ball or dart adapted to seat on a surface of the sleeve to close the passageway.   
     
     
         7 . A tool as claimed in  claim 6  further including a cup-shaped member having an interior surface conforming to the exterior surface of the ball or dart and engaging an uphole surface of the ball or dart. 
     
     
         8 . A tool as claimed in  claim 6  wherein the sleeve includes a valve seat. 
     
     
         9 . A method of treating a well having a production casing comprising:
 providing a production casing including a plurality of production casing members;   securing a tool having a valve seat and a through passageway at a predetermined position within the production casing;   perforating the production casing uphole of the tool;   closing the through passageway in the tool; and   pumping a treating fluid in the production casing and out through the perforations.   
     
     
         10 . The method of  claim 9  including:
 terminating the pumping of the treating fluid; 
 positioning a second tool in the production casing upstream of the perforations in the production casing; 
 perforating the production casing at a second location uphole of the second tool and resuming pumping of the treating fluid in the production casing and through perforations located in the second location. 
 
     
     
         11 . The method of  claim 9  wherein the tool includes a collet having a plurality of resilient fingers with tabs, the tabs adapted to be captured by a gap formed between adjacent production casing members. 
     
     
         12 . The method of  claim 9  wherein the tool includes a collet having a plurality of resilient fingers with tabs, the tabs adapted to be captured by a groove within a connection sub that connects two adjacent production casing members together.