Well Bore Tool With Ball Seat Assembly

Abstract

Tools for a well tubular comprising a ball seat assembly. The ball seat assembly comprises first and second ball seats. The first ball seat is adapted to receive a ball deployed into the tool, transition to a second state and release the ball. The first ball seat is operatively engaged with the second ball seat such that as it transitions to its second state it causes the second ball seat to transition from a first state of increased clearance to a second state having reduced clearance. The second seat then is adapted to receive the ball after it is released by the first seat. The second ball seat is adapted to actuate the tool, transition to a third state, and release the ball. The clearance through the second ball seat in its second state is less than the clearance through the first ball seat in its first state.

What is claimed is: 
     
         1 . A tool for a well tubular, said tool comprising:
 (a) a cylindrical housing adapted for assembly into a tubular for a well and defining a conduit for passage of fluids through said housing;   (b) a ball seat assembly, said ball seat assembly comprising first and second ball seats mounted in said conduit, wherein:
 i) said first ball seat has a first state in which it is adapted to receive a ball deployed into said conduit and is adapted to transition to a second state in response to receiving said ball, in which second state it is adapted to release said ball; 
 ii) said first ball seat is operatively engaged with said second ball seat such that as said first ball seat transitions to its second state it causes said second ball seat to transition from a first state having increased clearance to a second state having reduced clearance, in which second state said second seat is adapted to receive said ball for actuation of said tool after said ball is released by said first seat; 
 iii) said second ball seat is adapted to actuate said tool and transition to a third state in response to receiving said ball, in which third state it is adapted to release said ball; and 
 iv) wherein the clearance through said second ball seat in its second state is less than the clearance through said first ball seat in its first state. 
   
     
     
         2 . The tool of  claim 1 , wherein the clearances through said first ball seat in its second state and through said second ball seat in its third state are sized to allow backflow of said ball through said seats with production fluids from said well. 
     
     
         3 . The tool of  claim 1 , wherein said first ball seat is adapted to remain in its second state after releasing said ball. 
     
     
         4 . The tool of  claim 1 , wherein, said first ball seat comprises a split ring, said first split ring being compressed in said first state and being expanded in said second state and wherein said second ball seat comprises a split ring, said second split ring being expanded in said first state, compressed in said second state, and expanded in said third state. 
     
     
         5 . The tool of  claim 1 , wherein said first ball seat is in its first state when said tool is configured for assembly into said tubular and run into said well. 
     
     
         6 . The tool of  claim 1 , wherein said second ball seat is mounted in said conduit below said first ball seat. 
     
     
         7 . The tool of  claim 1 , wherein said first ball seat is mounted in said conduit for downward linear movement relative to said housing, said first ball seat adapted to cause said second seat to transition to its second state as said first ball seat moves down said conduit. 
     
     
         8 . The tool of  claim 7 , wherein said first ball seat is carried in an area of reduced diameter in its first state and is adapted to move down said conduit into an area of enlarged diameter, whereby said first ball seat transitions to its said second state by radial displacement outward into said enlarged diameter area. 
     
     
         9 . The tool of  claim 1 , wherein said second ball seat is mounted in said conduit for downward linear movement relative to said housing, said second ball seat adapted to transition to its second and third states as said second ball seat moves down said conduit. 
     
     
         10 . The tool of  claim 9 , wherein said second ball seat is carried in an area of enlarged diameter in its first state and is adapted to move down said conduit into an area of reduced diameter, whereby said second ball seat transitions to its said second state by being displaced radially inward by said reduced diameter area. 
     
     
         11 . The tool of  claim 10 , wherein said second ball seat is adapted to move down said conduit from said reduced diameter area to another area of enlarged diameter, whereby said second ball seat transitions to its said third state by radial displacement outward into said enlarged diameter area. 
     
     
         12 . A tool for a well tubular, said tool comprising:
 (a) a cylindrical housing adapted for assembly into a tubular for a well and defining a conduit for passage of fluids through said housing;   (b) a ball seat assembly, said ball seat assembly comprising first and second ball seats mounted in said conduit, wherein:
 i) said first ball seat has a first state in which it is adapted to receive a ball deployed into said conduit and is adapted to transition to a second state in response to receiving said ball, in which second state it is adapted to release said ball; 
 ii) said first ball seat is operatively engaged with said second ball seat such that as said first ball seat transitions to its second state it causes said second ball seat to transition from a first state having reduced load capacity to a second state having increased load capacity, in which second state said second seat is adapted to receive said ball after said ball is released by said first seat; 
 iii) said second ball seat is adapted to transition to a third state in response to receiving said ball, in which third state it is adapted to release said ball; and 
 iv) wherein the load capacity of said first ball seat in its first state is less than the load capacity of said second ball seat in its second state. 
   
     
     
         13 . A tool for a well tubular, said tool comprising:
 (a) a cylindrical housing adapted for assembly into a tubular for a well and defining a conduit for passage of fluids through said housing; and   (b) a ball seat assembly, said ball seat assembly comprising:
 i) a first split ring operatively engaged with a first drive sleeve, said first split ring and first drive sleeve being adapted for downward linear movement through said conduit, said downward movement causing said first split ring to transition from a compressed state in which it forms a ball seat sized to receive a ball deployed into said conduit to an expanded state in which it is sized to release said ball; 
 ii) a second split ring adapted for downward linear movement though said conduit, said downward movement causing said second split ring to transition from an expanded state to a compressed state in which it forms a ball seat sized to receive said ball; 
 iii) wherein said first split ring is adapted to move down said conduit and transition to its expanded state in response to receiving said ball thereon; 
 iv) wherein said first drive sleeve operatively engages said second split ring as said first split ring moves down said conduit and causes said second split ring to move down said conduit and transition to its compressed state, whereby said second split ring, is adapted to receive said ball after said ball is released by said first split ring; 
 v) wherein the clearance through said ball seat formed by said second split ring in its compressed state is less than the clearance through said ball seat formed by said first split ring in its compressed state. 
   
     
     
         14 . The tool of  claim 13 , wherein said second split ring is adapted to move down said conduit after receiving said ball and transition back to an expanded state in which it is sized to release said ball. 
     
     
         15 . A stimulation valve for a well tubular, said stimulation valve comprising:
 (a) a cylindrical housing adapted for assembly into a tubular for a well and defining a conduit for passage of fluids through said housing and one or more ports allowing fluid communication between said conduit and the exterior of said housing;   (b) a valve body adapted for movement from a closed position restricting fluid communication through said ports to an open position allowing fluid communication through said ports; and   (c) a ball seat assembly, said ball seat assembly comprising first and second ball seats mounted in said conduit, wherein:
 i) said first ball seat has a first state in which it is adapted to receive a ball deployed into said conduit and is adapted to transition to a second state in response to receiving said ball, in which second state it is adapted to release said ball; 
 ii) said first ball seat is operatively engaged with said second ball seat such that as said first ball seat transitions to its second state it causes said second ball seat to transition from a first state having increased clearance to a second state having reduced clearance, in which second state said second seat is adapted to receive said ball for actuation of said valve body after said ball is released by said first seat; 
 iii) said second ball seat is adapted to transition to a third state in response to receiving said ball, in which third state it is adapted to release said ball; 
 iv) wherein said second ball seat is operatively engaged with said valve body such that as said second seat transitions to its third state it causes said valve body to move from its closed position to its open position; and 
 v) wherein the clearance through said second ball seat in its second state is less than the clearance through said first ball seat in its first state. 
   
     
     
         16 . The stimulation valve of  claim 15 , wherein said ball seat assembly is mounted in said conduit above said ports. 
     
     
         17 . The stimulation valve of  claim 15 , wherein said valve comprises a third ball seat mounted below said ports, said third ball seat being adapted to receive a ball to restrict fluid flow through said conduit. 
     
     
         18 . A tubular adapted for installation in a well comprising the tool of  claim 1 . 
     
     
         19 . A tubular adapted for installation in a well comprising an uphole tool and a downhole tool, said tools comprising the tools of  claim 1 . 
     
     
         20 . A method of lining a well, the method comprising installing a tubular comprising the tool of  claim 1 . 
     
     
         21 . A method of stimulating a formation in a well having a tubular comprising an uphole stimulation valve and a downhole stimulation valve, said stimulation valves comprising the stimulation valves of  claim 15 , said method comprising:
 (a) opening said uphole valve by pumping a ball through said uphole valve, said pumped ball causing said first ball seat in said uphole stimulation valve to transition to its second said state and said second ball seat in said uphole stimulation valve to transition to its third said state;   (b) opening said downhole valve by pumping said ball through said downhole valve, said pumped ball causing said first ball seat in said downhole stimulation valve to transition to its second said state and said second ball seat in said uphole stimulation valve to transition to its third said state; and   (c) pumping fluid through said tubular and out said opened valves to stimulate said formation adjacent to said valves.