Multistage Production System Incorporating Valve Assembly With Collapsible or Expandable C-Ring

Abstract

A valve assembly, and related system and method, with an annular sleeve having an inner surface with a diameter, a first cylindrical outer surface, and a plurality of openings extending between the inner surface and the first cylindrical outer surface. The annular sleeve includes a second cylindrical outer surface having a different diameter than the first cylindrical outer surface. A first C-ring having a body with a seating surface, opposing terminal ends, and an outer diameter extending from the body is at least partially within the inner surface of the sleeve. A coil spring is positioned around a portion of the sleeve and in an annular space at least partially defined by an annular body and the second cylindrical outer surface.

We claim: 
     
         1 . A valve assembly for use in a subterranean well for oil, gas, or other hydrocarbons, said valve assembly comprising:
 an annular sleeve having an inner surface with a diameter, a first cylindrical outer surface, and a plurality of openings extending between said inner surface and said first cylindrical outer surface, wherein said annular sleeve further comprises a second cylindrical outer surface having a different diameter than the first cylindrical outer surface.   a first C-ring having a body with a seating surface, opposing terminal ends, and an outer diameter extending from the body, wherein the first C-ring is at least partially within the inner surface of the sleeve; and   a coil spring positioned around a portion of the sleeve and in an annular space at least partially defined by an annular body and the second cylindrical outer surface.   
     
     
         2 . The valve assembly of  claim 1  wherein said first C-ring is aligned with a circumferential groove formed in the inner surface of the sleeve. 
     
     
         3 . The valve assembly of  claim 1  further comprising a plurality of dogs positioned between radially outward of the outer diameter. 
     
     
         4 . The valve assembly of  claim 1  further comprising a second seating surface having a second seating diameter. 
     
     
         5 . The valve assembly of  claim 4  wherein the second seating surface is formed in a ball seat. 
     
     
         6 . The valve assembly of  claim 4  wherein the second seating surface is formed in a second C-ring having a body, opposing terminal ends, and an outer diameter extending from the body, wherein the second C-ring is at least partially within the inner surface of the sleeve. 
     
     
         7 . The valve assembly of  claim 6  wherein when one of said first C-ring and said second C-ring is compressed, the other of said first C-ring and said second is uncompressed. 
     
     
         8 . The valve assembly of  claim 6  wherein the diameter of the seating surface of the first C-ring in a compressed state is smaller than the diameter of the seating surface of the second seating surface; and wherein the diameter of the seating surface of the first C-ring in an uncompressed state is larger than the diameter of the seating surface of the second seating surface. 
     
     
         9 . The valve assembly of  claim 6  wherein one of the first C-ring and the second C-ring is compressed and the other of the first C-ring and the second C-rings is uncompressed. 
     
     
         10 . The valve assembly of  claim 1  further comprising at least one first mounting element having a first diameter and at least one mounting element having a second diameter, wherein the sleeve is movable between a first position wherein the openings are aligned with the at least one first mounting element to the first C-ring and a second position wherein the openings are aligned with the at least one second mounting element. 
     
     
         11 . A system of valve assemblies for use in a subterranean well for oil, gas, or other hydrocarbons, said valve assembly comprising:
 a first set of at least two tools, wherein each tool of the first set of tools comprises a C-ring sized to be actuated by a first resistor element having a first size and movable within the tool interior between a first position in which the C-ring is compressed and a second position in which the C-ring is uncompressed;   a second set of at least two tools, wherein each tool of the second set of tools comprises a C-ring sized to be actuated by a second resistor element having a second size that is smaller than the first size, and is further movable within the tool interior between a first position in which the C-ring is compressed and a second position in which the C-ring is uncompressed;   a first static seat tool positioned between the first set of tools and the second set of tools, said first static seat having seating surface sized to engage with the first resistor element and not engage with the second resistor element; and   wherein each tool of said first set of tools and said second set of tools comprises an annular sleeve at least partially encircling the corresponding C-ring and a spring positioned in an annular space partially defined by the corresponding sleeve and operative to exert an expansive force against the sleeve to resist a force applied to the seat by an resistor element of corresponding ball size.   
     
     
         12 . A method for treating a well for oil, gas or other hydrocarbons, the method comprising:
 causing a first resistor element to pass through a first set of tools and a first static seat to at least one compressed C-ring of a second set of tools;   seating the first resistor element to against the seating surface of the at least one compressed C-ring, wherein the at least one compressed C-ring is associated with at least one sleeve in a first position;   causing a pressure differential of a first pressure value across the first resistor element, said pressure value greater than an opposing expansive force of at least one spring associated with the at least one compressed C-ring to move the at least one sleeve to a second position wherein the at least one C-ring becomes uncompressed;   causing the first resistor element to flow through the at least one C-ring; and   returning the at least one sleeve to the first position using an expansive force of the at least one spring.