Well screens having distributed flow

Abstract

Well screens having distributed flow. A well screen includes a generally tubular structure having a longitudinal axis, and a passage for flow between an interior and an exterior of the well screen; and a filter assembly having a restriction to flow which varies in a direction parallel to the longitudinal axis. A well system includes a well screen including a passage for flow between an interior and an exterior of the well screen, and a filter assembly having a series of longitudinally extending sections, the series of filter assembly sections having a restriction to flow which increases in a direction toward the passage.

1 . A well screen, comprising: 
 a longitudinal axis; and    a filter assembly having a restriction to flow which varies in a direction parallel to the longitudinal axis.    
   
   
       2 . The well screen of  claim 1 , further comprising a passage for flow between an interior and an exterior of the well screen, and wherein the restriction to flow increases in the direction toward the passage.  
   
   
       3 . The well screen of  claim 1 , wherein the restriction to flow varies in discrete increments.  
   
   
       4 . The well screen of  claim 1 , wherein the restriction to flow varies continuously.  
   
   
       5 . The well screen of  claim 1 , wherein the varied restriction to flow results from a variation in a filter material of the filter assembly, and where the variation is in at least one of density, permeability, porosity, bonding resin, matrix, thickness, particle size, consolidation, and material type of the filter material.  
   
   
       6 . The well screen of  claim 1 , wherein the varied restriction to flow is a result of a varied number of layers of filter material in the filter assembly.  
   
   
       7 . The well screen of  claim 1 , wherein the varied restriction to flow is a result of a varied number of openings in the filter assembly.  
   
   
       8 . The well screen of  claim 1 , wherein the varied restriction to flow is a result of a varied size of openings in the filter assembly.  
   
   
       9 . The well screen of  claim 1 , wherein the varied restriction to flow is a result of a varied spacing between successive elements of the filter assembly.  
   
   
       10 . The well screen of  claim 1 , wherein the passage extends through a device which restricts flow of a fluid which flows through the filter assembly.  
   
   
       11 . A well system, comprising: 
 a well screen including a passage for flow between an interior and an exterior of the well screen, and a filter assembly having a series of longitudinally extending sections, the series of filter assembly sections having a restriction to flow which increases in a direction toward the passage.    
   
   
       12 . The well system of  claim 11 , wherein a first one of the sections overlies the passage, and a second one of the sections is farther from the passage than the first section, the restriction to flow through the first section being greater than the restriction to flow through the second section.  
   
   
       13 . The well system of  claim 11 , wherein the restriction to flow varies in discrete increments.  
   
   
       14 . The well system of  claim 11 , wherein the restriction to flow varies continuously in the series of sections.  
   
   
       15 . The well system of  claim 11 , wherein the increased restriction to flow results from a variation in a filter material of the filter assembly, and where the variation is in at least one of density, permeability, porosity, bonding resin, matrix, thickness, particle size, consolidation, and material type of the filter material.  
   
   
       16 . The well system of  claim 11 , wherein the increased restriction to flow is a result of an increased number of layers of filter material in the filter assembly.  
   
   
       17 . The well system of  claim 11 , wherein the increased restriction to flow is a result of a decreased number of openings in the filter assembly.  
   
   
       18 . The well system of  claim 11 , wherein the increased restriction to flow is a result of a decreased size of openings in the filter assembly.  
   
   
       19 . The well system of  claim 11 , wherein the increased restriction to flow is a result of a decreased spacing between successive elements of the filter assembly.  
   
   
       20 . The well system of  claim 11 , wherein the passage extends through a device which restricts flow of a fluid which flows through the filter assembly.  
   
   
       21 . A well screen, comprising: 
 a tubular structure made up of multiple longitudinal tubular structure sections; and    a filter assembly made up of multiple longitudinal filter assembly sections.    
   
   
       22 . The well screen of  claim 21 , further comprising a passage for flow between an interior and an exterior of the well screen, and wherein the filter assembly sections have a restriction to flow which increases in a direction toward the passage.  
   
   
       23 . The well screen of  claim 21 , wherein the tubular structure has a longitudinal axis, and wherein the filter assembly has a restriction to flow which varies in a direction parallel to the longitudinal axis.  
   
   
       24 . The well screen of  claim 21 , wherein the tubular structure sections are joined to each other with flush threaded joints.  
   
   
       25 . The well screen of  claim 21 , wherein the filter assembly sections are joined to each other with flush threaded joints.