Alternate path gravel packing with enclosed shunt tubes

Abstract

Apparatus for gravel packing a wellbore interval with enclosed alternate flowpaths (i.e. conduits) that can provide a good distribution of gravel over the entire completion interval. The alternate flowpaths for the slurry are positioned in the annulus formed by the base pipe and the external surface of the screen, and connected to corresponding exit nozzle chambers positioned at different levels on the screen, and therefore do not significantly increase the overall effective outside diameter of the screen.

1 . A well screen comprising: 
 a base pipe having openings through the wall thereof;    an outer surface having a top and having a section mounted over said base pipe, some of said surface of said section being permeable to fluids and abating the flow of particulate material, said outer surface having standoff from said base pipe, to form an annulus between the said base pipe and said outer surface;    at least one section of exit nozzle chambers, said section placed over said base pipe and adjacent to said permeable outer surface section;    at least one shunt tube positioned inside said annulus and secured to the inside of said outer surface and extending axially along said base pipe adjacent to said permeable section of said outer surface;    said section of exit nozzle chambers secured to said outer surface, said nozzle chamber section having multiple exit ports circumferentially spaced around said nozzle chamber section, said exit nozzle chambers being connected to said shunt tube for communicating with the outside of said outer surface of said screen;    an outer member having side openings and mounted on said top of said outer surface, and forming an annulus between said outer member and said base pipe with openings through the exterior of the sides of said outer member, permitting fluid flow to said annulus from the exterior to said outer member.    
   
   
       2 . The well screen of  claim 1 , wherein there are several permeable sections of said outer surface.  
   
   
       3 . The well screen of  claim 2 , wherein there are further included longitudinal support rods secured to the inside of said outer surface, thereby causing said outer surface to stand off from said base pipe.  
   
   
       4 . The well screen of  claim 3 , wherein said support rods are welded to the inside of said outer surface.  
   
   
       5 . The well screen of  claim 4 , wherein said shunt tube is interspersed with said longitudinal support rods.  
   
   
       6 . The well screen of  claim 5 , wherein said shunt tube is welded to the inside of said outer surface.  
   
   
       7 . The well screen of  claim 3 , wherein said outer surface includes multiple sections of a wire wrapped around said shunt tube and said longitudinal support rods, each wrap of said wire being spaced from the adjacent wraps to create openings between said wraps of wire.  
   
   
       8 . The well screen of  claim 2 , wherein said section of exit nozzle chambers is placed over said base pipe and alternates with sections of said outer surface.  
   
   
       9 . The well screen of  claim 1 , wherein said exit ports of nozzle inserts includes material used for erosion abatement.  
   
   
       10 . The well screen of  claim 2  where there is included: a multiple number of said shunt tubes radially spaced around said base pipe within said annulus and extending along said base pipe in said permeable sections of said outer surface and connected to said exit nozzle chamber sections of said outer surface, thereby at least one flow path is established.  
   
   
       11 . A well screen for use with fluid in slurry in a flow stream, comprising: 
 a plurality of joints, each of said joints having    a base pipe having openings through the wall thereof;    an outer surface having a top and having a section mounted over said base pipe, some of said surface of said section being permeable to fluids and abating the flow of particulate material, said outer surface having standoff from said base pipe, to form an annulus between the said base pipe and said outer surface;    at least one section of exit nozzle chambers, said section placed over said base pipe and adjacent to said permeable outer surface section;    at least one shunt tube positioned inside said annulus and secured to the inside of said outer surface and extending axially along said base pipe adjacent to said permeable section of said outer surface;    said section of exit nozzle chambers secured to said outer surface, said nozzle chamber section having multiple exit ports circumferentially spaced around said nozzle chamber section, said exit nozzle chambers being connected to said shunt tube for communicating with the outside of said outer surface of said screen;    a coupling joining adjacent ones of said joints together forming a common manifold area, whereby said coupling permits said at least one shunt tube in one each of said joints being in fluid connection which is connected to said common manifold area and thereby in communication with said exit nozzle chambers and at least one shunt tube of the adjoining joints of said joint;    an outer member having side openings and mounted on said top of said outer surface, and forming annulus in the upper most joint of said joints between said outer member and said base pipe for joining adjacent ones of said joints and top of said outer surface with openings through the exterior of the sides of said outer member, permitting fluid flow to said annulus from the exterior to said outer member.    
   
   
       12 . The well screen of  claim 11  where said mechanism joining said joints includes: 
 a fluid means for fluid in slurry to return to the flow stream in the said shunt tubes.    
   
   
       13 . The well screen of  claim 12  wherein said fluid means includes a box end at one end of said base pipe, said box end having threads for attachment to an adjacent one of said plurality of joints; 
 an external circumferential groove above said threads; and    a slotted plate covering said external circumferential groove.    
   
   
       14 . The well screen of  claim 11  where said mechanism includes connection means for joining adjacent ones of said joints, and the flow stream is in said base pipe and further including: 
 a fluid means for the fluid in slurry to return to the flow stream in said base pipe;    a slotted external concentric pipe positioned between said exit nozzle chamber that is the highest mounted and said threaded box, said slotted external concentric pipe forming an annulus with said inner concentric pipe and said threaded box and having a bored channel therein, said bored channel being in fluid connection with said annulus and in further fluid communication with the flow stream in said base pipe.    
   
   
       15 . The well screen of  claim 11  where there are a multiple number of said shunt tubes radially spaced around said base pipe within said annulus and extending along said base pipe in said permeable section of said outer surface and connected to said exit nozzle chamber sections of said outer surface.  
   
   
       16 . A method for placement of gravel slurry for gravel packing an interval of a wellbore in the presence of a block by a sand bridge or void formed in a well annulus before the placement of the gravel slurry in the gravel packing is complete, the well annulus being formed between a tool, having a screen, with exit nozzle chambers placed at different points along the screen, inside the wellbore, which screen at least partially surrounds a base pipe of the tool forming a tube annulus, comprising the steps of: 
 A. providing conduits and the arrangement of conduits positioned between the base pipe and the screen in the tube annulus and connected to the exit nozzle chambers;    B. filling the well annulus with gravel slurry until the well annulus is blocked;    C. after step B, flowing the gravel slurry into the conduits in the tube annulus past the well annulus block;    D. causing the gravel slurry flow of step C to flow from the tube annulus through said exit nozzle chambers to the well annulus.    
   
   
       17 . The method of  claim 16  wherein the conduits are unperforated flow conduits.  
   
   
       18 . The method of  claim 16  wherein the conduits are alternate flow paths.  
   
   
       19 . The method of  claim 16  wherein the conduits are shunt tubes.  
   
   
       20 . The method of  claim 16  wherein the conduits are round conduits.  
   
   
       21 . The method of  claim 16  wherein the alternate flow paths are spaced radially around the base pipe within the tube annulus.  
   
   
       22 . The method of  claim 16  wherein the gravel slurry is introduced interior to the tool.  
   
   
       23 . The method of  claim 16  wherein the well bore is sealed in its upper end by the tool preventing the flow of gravel slurry upward into the well annulus.  
   
   
       24 . The method of  claim 16  wherein the gravel slurry flows through the interior of the tool and through a crossover tool to flow into the well annulus.  
   
   
       25 . The method of  claim 16  wherein the gravel slurry flows from the annulus through the screen to the shunt tubes and returns through the interior of the tool.