Well Screen With Drainage Assembly

Abstract

A well screen assembly has an elongate base pipe having apertures therein. A filtration layer resides around the base pipe. A drainage assembly resides between the base pipe and the filtration layer. The drainage assembly includes a plurality of elongate risers carried on a mesh. The drainage layer supports the filtration layer apart from the elongate base pipe and defines an elongate passage between the base pipe and the filtration layer that communicates fluid laterally through the drainage assembly.

1 . A well screen assembly, comprising:
 an elongate base pipe having apertures therein;   a filtration layer around the base pipe; and   a drainage assembly between the base pipe and the filtration layer, the drainage assembly comprising a plurality of elongate risers carried on a mesh, the drainage layer supporting the filtration layer apart from the elongate base pipe and defining an elongate passage between the base pipe and the filtration layer that communicates fluid laterally through the drainage assembly.   
     
     
         2 . The well screen assembly of  claim 1 , wherein the plurality of risers comprise wires of a second mesh carried by the first mentioned mesh. 
     
     
         3 . The well screen assembly of  claim 2 , wherein the second mesh is a non-woven mesh. 
     
     
         4 . The well screen assembly of  claim 1 , wherein the plurality of risers are not arranged in a mesh. 
     
     
         5 . The well screen assembly of  claim 1 , wherein the risers are oriented substantially longitudinally with respect to the elongate base pipe and the elongate passage extends substantially the entire length of the drainage assembly unobstructed by structures transversely crossing the passage. 
     
     
         6 . The well screen assembly of  claim 1 , wherein the risers define a plurality of elongate passages and the of passages are substantially parallel to one another. 
     
     
         7 . The well screen assembly of  claim 1 , wherein the filtration layer is a wire mesh and the risers are of a lower gage than the wires of the filtration layer wire mesh. 
     
     
         8 . The well screen assembly of  claim 1 , wherein the filtration layer is a wire mesh and a greatest dimension between wires of the filtration layer wire mesh is smaller than a greatest dimension between risers of the drainage assembly. 
     
     
         9 . The well screen assembly of  claim 8 , wherein the filtration layer is a wire mesh and a greatest dimension between wires of the filtration layer wire mesh is smaller than a greatest dimension between wires of the drainage assembly mesh. 
     
     
         10 . The well screen assembly of  claim 1 , further comprising an apertured shroud pipe around the filtration layer. 
     
     
         11 . A screen assembly for use in a well, comprising:
 an elongate apertured tubing;   a first mesh layer carried on the tubing;   a second mesh layer between the first mesh layer and the apertured tubing; and   a third, non-woven mesh layer between the second mesh layer and the apertured tubing, the third, non-woven mesh layer formed from a planar non-woven mesh sheet wrapped into a cylindrical shape, the planar sheet having a first plurality of wires oriented in generally the same direction and residing in a first plane and a second plurality of wires affixed to the first plurality of wires and residing in a second plane.   
     
     
         12 . The screen assembly of  claim 11 , wherein the third, non-woven mesh layer comprises a square mesh. 
     
     
         13 . The screen assembly of  claim 11 , wherein the first plurality of wires are oriented substantially longitudinally along the elongate apertured tubing and define an elongate passage that extends substantially the entire longitudinal dimension of the third, non-woven mesh layer unobstructed by structures transversely crossing the passage. 
     
     
         14 . The screen assembly of  claim 11 , wherein first mesh layer is a wire mesh and the first plurality of wires of the third, non-woven mesh are of a lower gage than the wires of the first mesh layer. 
     
     
         15 . The screen assembly of  claim 11 , wherein the first mesh layer is a wire mesh and a greatest dimension between wires of the first mesh layer is smaller than a greatest dimension between the first plurality of wires of the third, non-woven mesh. 
     
     
         16 . The screen assembly of  claim 11 , wherein the third, non-woven mesh is affixed to the second mesh. 
     
     
         17 . A method of communicating fluids in a well, comprising:
 filtering particulate from a fluid with a filtration layer of a well screen assembly; and   communicating the fluid laterally through the well screen assembly via an elongate passage defined in a drainage assembly of the well screen assembly, the drainage assembly residing between the filtration layer and a base pipe of the well screen assembly and comprising a plurality of elongate risers carried on a mesh that support the filtration layer apart from the elongate base pipe and define the elongate passage.   
     
     
         18 . The method of  claim 17 , wherein the plurality of risers comprise wires of a second, non-woven mesh carried by the first mentioned mesh. 
     
     
         19 . The method of  claim 17 , wherein the plurality of risers are not arranged in a mesh. 
     
     
         20 . The method of  claim 17 , wherein the risers are oriented substantially longitudinally with respect to the elongate base pipe and the elongate passage extends substantially the entire length of the drainage assembly unobstructed by structures transversely crossing the passage.