Valve system and method

Abstract

A system and method for a valve system for downhole use with downhole tools such as packers is disclosed. The valve system includes an opening piston and a closing piston which preferably utilize any suitable means to control erosion such as, for example only, carbide inserts that define the various inlets and outlets of the opening and closing piston. Preferably a carbide baffle is used to produce a slower and smoother fluid pressure flow through the valve system. Pressure from the casing bore above a selected value causes opening piston to shift and permit fluid flow past the valve stem of the closing piston and into the filling port of the packer. When pressure inside the inflatable packer produces a force on the closing piston above a selected amount, the closing piston shifts to the closed position whereby fluid flow into or out of the inflatable packer is prevented. Once pressure is bled off the casing bore, the return spring of the opening piston pushes the piston back to seal off the port. A non-elastomeric seal such as a TEFLON seal and/or an elastomeric seal may be bonded to the closing piston is provided to resist forces that could otherwise damage the seal as the closing piston is shifted to the closed position. An equalizer valve is preferably built into the opening piston equalize hydrostatic pressure to the casing bore.

What is claimed is:  
     
         1 . A valve system for a downhole tool, comprising: 
 a valve body;    an opening valve assembly within said valve body, said opening valve assembly having an opening piston, said opening piston being moveable from a closed position to an open position in response to pressure acting thereon to open a flow path through said valve body; and    a closing valve assembly within said valve body, said flow path extending through said closing valve assembly when said opening piston is in said open position.    
     
     
         2 . The valve system of  claim 1 , further comprising: 
 a sleeve surrounding said opening valve assembly.    
     
     
         3 . The valve system of  claim 1 , further comprising: 
 said valve body defining a machined aperture, said sleeve slidably fitting into said aperture.    
     
     
         4 . The valve system of  claim 1 , further comprising: 
 a sleeve surrounding said closing valve assembly.    
     
     
         5 . The valve system of  claim 1 , further comprising: 
 a baffle having a plurality of walls therein, each of said plurality of walls defining a one or more openings.    
     
     
         6 . The valve system of  claim 1 , wherein said flow path through said closing piston extends around a closing piston valve stem.  
     
     
         7 . The valve system of  claim 1 , wherein: 
 said closing piston is moveable to close said flow path.    
     
     
         8 . The valve system of  claim 1 , further comprising a seal bonded to said closing piston.  
     
     
         9 . The valve system of  claim 1 , further comprising a non-elastomeric seal on said closing piston.  
     
     
         10 . The valve system of  claim 1 , further comprising an elastomeric seal on said closing piston adjacent said non-elastomeric seal.  
     
     
         11 . The valve system of  claim 1 , further comprising: 
 an equalizer valve mounted within said opening piston.    
     
     
         12 . A method for a valve system for a downhole tool with an inflatable element, said method comprising: 
 applying pressure to an opening piston for moving said opening piston from an original position to a shifted position to thereby open a flow path through said valve system for filling said inflatable element; and    connecting internal pressure from said inflatable element of said downhole tool to a closing piston such that said closing piston moves from an original position to a closed position after said internal pressure reaches a selected pressure, said movement of said closing piston closing said flow path to prevent further fluid flow into said inflatable element.    
     
     
         13 . The method of  claim 12 , further comprising: 
 biasing said opening piston such that said opening piston moves back to said original position by reducing said applied pressure, and    locking said opening piston in said original position.    
     
     
         14 . The method of  claim 12 , further comprising: 
 shearing a shearable member in response to said step of applying pressure to permit movement of said opening piston.    
     
     
         15 . The method of  claim 12 , further comprising: 
 bonding a sealing element to said closing piston.    
     
     
         16 . The method of  claim 12 , further comprising: 
 providing a non-elastomer as a sealing element of said closing piston.    
     
     
         17 . The method of  claim 12 , further comprising: 
 providing an elastomeric adjacent said non-elastomer sealing element.    
     
     
         18 . The method of  claim 12 , further comprising: 
 equalizing pressure inside said inflatable element to a wellbore.    
     
     
         19 . The method of  claim 12 , further comprising: 
 impeding fluid flow into said fluid flow path with a baffle.    
     
     
         20 . The method of  claim 12 , further comprising: 
 providing said flow path through said closing valve assembly such that after said opening piston moves, then fluid flow occurs through said flow path into said inflatable element.    
     
     
         21 . A method for a valve system for a downhole tool with an inflatable element, said method comprising: 
 providing a valve body with a first cylinder for an opening piston, said opening piston being moveable between an open position and a closed position for controlling fluid flow for said inflatable element;    providing said valve body with a second cylinder for a closing piston, said closing piston being moveable between an open position and a closed position for controlling said fluid flow for said inflatable element;    inserting a first cylinder liner in said valve body around said opening piston, and    inserting a second cylinder liner in said valve body around said closing piston.    
     
     
         22 . The method of  claim 21 , further comprising: 
 providing ports through said first cylinder liner and said second cylinder liner.    
     
     
         23 . The method of  claim 21 , further comprising: 
 machining said first cylinder and said second cylinder in said valve body for receiving said first cylinder liner and said second cylinder liner, respectively.    
     
     
         24 . The method of  claim 21 , further comprising: 
 bonding a sealing element to said closing piston.    
     
     
         25 . The method of  claim 21 , further comprising: 
 providing a non-elastomer as a sealing element of said closing piston.    
     
     
         26 . The method of  claim 21 , further comprising: 
 providing a plurality of walls with offset openings therebetween for impeding said fluid flow into said valve body.    
     
     
         27 . The method of  claim 21 , further comprising: 
 providing said flow path through said closing valve assembly such that when said opening piston is in said open position, then said fluid flow occurs through said flow path into said inflatable element.    
     
     
         28 . The method of  claim 21 , further comprising: 
 providing a locking assembly for locking said opening position in said closed position after said inflatable element is inflated.    
     
     
         29 . The method of  claim 21 , further comprising: 
 forming a equalizing valve in said opening position to permit said fluid flow through said opening piston when said opening piston is in said closed position.    
     
     
         30 . A valve system for a downhole tool, comprising: 
 a valve body, said valve body having a fluid flow path therethrough;    a valve assembly disposed within said valve body;    a baffle assembly for said valve body, said baffle assembly comprising a plurality of walls spaced apart and secured with respect to each other, said plurality of walls defining one or more ports, said baffle assembly receiving fluid flow for said fluid flow path.    
     
     
         31 . The valve system of  claim 30 , wherein said valve assembly disposed within said valve body further comprises: 
 an opening valve assembly within said valve body, said opening valve assembly having an opening piston, said opening piston being moveable in response to pressure acting thereon from a closed position to an open position to open a flow path through said valve body; and    a closing valve assembly within said valve body, said flow path extending through said closing valve assembly when said opening piston is in said open position.    
     
     
         32 . The valve system of  claim 31 , further comprising: 
 a sleeve surrounding at least one of said opening valve assembly or said closing valve assembly.    
     
     
         33 . The valve system of  claim 31 , wherein said flow path through said closing piston extends around a closing piston valve stem.  
     
     
         34 . The valve system of  claim 31 , wherein: 
 said closing piston is moveable in response to pressure acting thereon to close said flow path.    
     
     
         35 . The valve system of  claim 31 , further comprising a seal bonded to said closing valve piston.  
     
     
         36 . The valve system of  claim 31 , further comprising a non-elastomeric seal on said closing piston.  
     
     
         37 . The valve system of  claim 31 , further comprising: 
 an equalizing valve mounted within said opening piston.    
     
     
         38 . The valve system of  claim 31 , further comprising: 
 said valve body defining a machined aperture, and    a sleeve slidably fitting into said aperture.    
     
     
         39 . The valve system of  claim 31 , wherein said baffle assembly receives said fluid flow prior to said fluid flow entering said fluid flow path through said valve body.  
     
     
         40 . A valve system for a downhole tool controlling fluid flow to an expandable member, comprising: 
 a valve body;    at least one valve assembly within said valve body, said at least one valve assembly having at least one piston; and    at least one non-elastomer seal disposed on said at least one piston.    
     
     
         41 . The valve system of  claim 40 , further comprising: 
 an elastomer seal adjacent said non-elastomer seal.    
     
     
         42 . The valve system of  claim 41 , further comprising: 
 at least one of said elastomer seal or said non-elastomer seal being bonded to said at least one piston.    
     
     
         43 . The valve system of  claim 40 , further comprising: 
 an opening valve assembly with an opening piston within said valve body,    a closing valve assembly with a closing piston within said valve body, said non-elastomer seal being provided on said closing piston.    
     
     
         44 . The valve system of  claim 43 , further comprising: 
 said flow path extending through said closing valve assembly when said opening piston is in said open position.    
     
     
         45 . The valve system of  claim 44 , further comprising hardened sleeves insertable into said valve body to resist erosion due to said fluid flow.  
     
     
         46 . The valve system of  claim 44 , wherein said opening valve assembly and said closing valve assembly are hardened to resist erosion due to said fluid flow.