Robust sand screen for oil and gas wells

Abstract

According to a first preferred aspect of the invention, there is provided a downhole sand screen device for use in well completions that comprises a plurality of isolated individual sand screens. Further, in the preferred arrangement the instant invention consists of two screens, one concentrically nested inside of the other, and further wherein the screen sections are not continuous but rather are periodically interrupted by sections of blank pipe. Further, the screen sections are arranged so that a screen section on the outer pipe will be matched by a corresponding, but staggered, blank pipe section on the inner pipe. As a consequence, if a hole develops in one of the outer screen sections the movement of sand will be blocked from entering the wellbore by a second/inner screen.

1 . A device for use in a well completion, said device having an interior volume suitable for withdrawing fluid from the subsurface, comprising: 
 a. an outer cylindrical member, said outer cylindrical member having an outer blank pipe section and an outer screen section, 
 (a1) wherein said outer blank pipe section is substantially cylindrical in shape and forms at least a portion of an outer surface of said outer cylindrical member, and,  
 (a2) wherein said outer screen section is substantially cylindrical in shape and forms at least a portion of said outer surface of said outer cylindrical member, and,  
 (a3) wherein outer blank pipe section and said outer screen section are contiguous to each other;  
   b. an inner cylindrical member positioned within said outer cylindrical member and coaxial therewith, wherein said inner cylindrical member has an inner blank pipe section and an inner screen section, 
 (b1) said inner blank pipe section being substantially cylindrical in shape and forming at least a portion of an outer surface of said inner cylindrical member, and,  
 (b2) said inner screen section being substantially cylindrical in shape and forming at least a portion of said outer surface of said inner cylindrical member,  
 (b3) wherein inner blank pipe section and said inner screen section are contiguous to each other, and,  
 (b4) wherein said inner cylindrical member is oriented such that said outer blank pipe section is proximate to said inner cylindrical screen section and said outer screen section is proximate to said inner blank pipe section; and,  
   c. a spacer situated between said inner cylindrical member and said outer cylindrical member, said spacer being in mechanical communication with said inner cylindrical member and said outer cylindrical member, said spacer being at least for maintaining said inner cylindrical member and said outer cylindrical member in a spaced apart relationship, said outer cylindrical member, said inner cylindrical member, and said spacer together comprising a segment.    
   
   
       2 . A device for use in a well completion according to  claim 1 , wherein said spacer completely encircles said inner cylindrical member.  
   
   
       3 . A device for use in a well completion according to  claim 2 , wherein said spacer is impermeable to the passage of said fluid therethrough.  
   
   
       4 . A device for use in a well completion according to  claim 3 , 
 wherein said device is comprised of at least two adjacent segments, and    wherein each of said at least two segments has a void between its inner cylindrical member and its outer cylindrical member, and    wherein each of said segment voids is maintained in fluid isolated from the other by said one or more spacers.    
   
   
       5 . A device for use in a well completion according to  claim 1 , wherein said first outer blank pipe section has a first predetermined length and said first outer screen section has a same first predetermined length.  
   
   
       6 . A device for use in a well completion according to  claim 5 , wherein said first inner blank pipe section has a second predetermined length and said first inner screen section has a same second predetermined length.  
   
   
       7 . A device for use in a well completion according to  claim 6 , wherein said first predetermined length and said second predetermined length are substantially equal.  
   
   
       8 . A device for use in a well completion according to  claim 1 , wherein said first outer screen section is comprised of a material selected from a list consisting of stainless steel and aluminum.  
   
   
       9 . A device for use in a well completion according to  claim 1 , wherein said first inner screen section is comprised of a material selected from a list consisting of stainless steel and aluminum.  
   
   
       10 . A device for use in a well completion, said device having an interior volume suitable for withdrawing fluid from the subsurface, comprising: 
 a. an outer pipe member, said outer pipe member having a first outer blank pipe section and a first outer screen section, 
 (a1) wherein said first outer blank pipe section is substantially cylindrical in shape and forms at least a portion of an outer surface of said outer pipe member, and,  
 (a2) wherein said first outer screen section is substantially cylindrical in shape and forms at least a portion of said outer surface of said outer pipe member, and,  
 (a3) wherein first outer blank pipe section and said first outer screen section are proximate to each other; and,  
   b. an inner pipe member positioned within said outer pipe member, wherein said inner pipe member comprises a first inner blank pipe section and a first inner screen section, 
 (b1) said first inner blank pipe section being substantially cylindrical in shape and forming at least a portion of an outer surface of said inner pipe member, and,  
 (b2) said first inner screen section being substantially cylindrical in shape and forming at least a portion of said outer surface of said inner pipe member,  
 (b3) wherein first inner blank pipe section and said first inner screen section are proximate to each other, and,  
 (b4) wherein said inner pipe member is oriented with respect to said outer pipe member such that 
 (i) said first outer blank pipe section is proximate to said first inner screen section, said first inner screen section being positioned between said outer blank pipe section and an interior of said inner pipe member, and,  
 (ii) said first outer screen section is proximate to said first inner blank pipe section, said first inner blank pipe section being positioned between said outer screen section and said interior of said inner pipe member.  
 
   
   
   
       11 . A device for use in a well completion according to  claim 10 , further comprising: 
 c. a spacer situated between said inner pipe member and said outer pipe member, said spacer being in mechanical communication with said inner pipe member and said outer pipe member, said spacer being at least for maintaining said inner pipe member and said outer pipe member in a spaced apart relationship, said outer pipe member, said inner pipe member, and said spacer together comprising a segment.    
   
   
       12 . A device for use in a well completion according to  claim 11 , wherein said spacer completely encircles said inner pipe member.  
   
   
       13 . A device for use in a well completion according to  claim 11 , wherein said spacer is impermeable to the passage of said fluid therethrough.  
   
   
       14 . A device for use in a well completion according to  claim 13 , 
 wherein said device is comprised of at least two adjacent segments, and    wherein each of said at least two segments has a void between its inner pipe member and its outer pipe member, and    wherein each of said segment voids is maintained in fluid isolated from the other by said one or more spacers.