A sealing device for temporarily closing a well or a pipe

Abstract

The device comprises a tubular membrane ( 3 ) of circular section, having a wall ( 30 ) of material that is leakproof, flexible, and elastic, e.g. of rubber, and that is inflatable and deformable radially outwards under the action of internal fluid pressure, said membrane ( 3 ) being mechanically reinforced by at least one sheet of flexible strands ( 6, 7 ); the device is remarkable in that it includes at least one and preferably a pair of adjacent and concentric cylindrical fiber layers ( 8, 9 ) embedded in the thickness of the wall ( 30 ) inside relative to the sheet of flexible strands ( 6, 7 ), and of a structure that acts as an anti-extrusion barrier, limiting creep of the material of the wall ( 30 ) and preventing it from passing outwards between said reinforcing wires / 6, 7 ) under the effect of the pressure generated by the inflation fluid. The device serves for temporarily closing the casing of an oil well or a variety of pipes.

1 . A sealing device ( 1 ) for temporarily closing a well or a pipe, the device comprising a support ( 2   a - 2   b ;  4 ,  40   a - 40   b ) supporting an inflatable tubular membrane ( 3 ) of circular section, having a wall ( 30 ) of material that is leakproof, flexible and elastic, and deformable radially outwards under the action of internal fluid pressure so as to be pressed hermetically against the wall (T) of the wall or the pipe, said membrane ( 3 ) being mechanically reinforced by at least one sheet of flexible strands ( 6 ,  7 ) embedded in the thickness of its wall, the sheet being inscribed in a circularly cylindrical surface on the same axis as said membrane, wherein the sealing device includes at least one fiber layer ( 8 ,  9 ), referred to as a “filter” layer, which is likewise circularly cylindrical in shape, and disposed concentrically, being embedded in the thickness of the wall ( 30 ) of the membrane ( 3 ), inside relative to said sheet of flexible strands ( 6 ;  7 ), said filter layer ( 8 ,  9 ) possessing a structure made up of a multitude of very fine fibers ( 80 , 90 ) that acts as an anti-extrusion barrier, adapted to limit creep of the material constituting the wall ( 30 ) of the membrane ( 3 ) and to prevent it from passing outwards between the reinforcing strands ( 6 ,  7 ) under the effect of the pressure (Pi) generated by the inflation fluid.  
   
   
       2 . A sealing device ( 1 ) for temporarily closing a well or a pipe, the device comprising a support ( 2   a - 2   b ;  4 ,  40   a - 40   b ) supporting an inflatable tubular membrane ( 3 ) of circular section, having a wall ( 30 ) of material that is leakproof, flexible and elastic, and deformable radially outwards under the action of internal fluid pressure so as to be pressed hermetically against the wall (T) of the wall or the pipe, said membrane ( 3 ) being mechanically reinforced by at least one sheet of flexible strands ( 6 ,  7 ) embedded in the thickness of its wall, the sheet being inscribed in a circularly cylindrical surface on the same axis as said membrane, wherein the sealing device includes at least one pair of adjacent fiber layers ( 8 ,  9 ), referred to as “filter” layers, which are likewise circularly cylindrical in shape, and are disposed concentrically one inside the other, being embedded in the thickness of the wall ( 30 ) of the membrane ( 3 ), inside relative to said sheet of flexible strands ( 6 ;  7 ), said pair of filter layers ( 8 ,  9 ) possessing a structure made up of a multitude of very fine fibers ( 80 , 90 ) that acts as an anti-extrusion barrier, adapted to limit creep of the material constituting the wall ( 30 ) of the membrane ( 3 ) and to prevent it from passing outwards between the reinforcing strands ( 6 ,  7 ) under the effect of the pressure (P i ) generated by the inflation fluid.  
   
   
       3 . A sealing device according to  claim 1 , wherein the filter layer(s) ( 8 ,  9 ) is/are made up of a multitude of very fine fibers ( 80 ,  90 ) which extend parallel to one another forming a helix of very long pitch, in a direction that is inclined at a small angle relative to the axis of revolution (Z-Z′) of the membrane ( 3 ).  
   
   
       4 . A sealing device according to claims  2  and  3  in combination, wherein the fibers ( 80 ,  90 ) constituting the two filter layers ( 8 ,  9 ) are inclined at the same acute angle (β 0 ) relative to said axis of revolution (Z-Z′) of the membrane ( 3 ), but in opposite directions.  
   
   
       5 . A sealing device according to  claim 4 , wherein the acute angle (β 0 ) formed by the fibers ( 80 ,  90 ) relative to said axis of revolution (Z-Z′) lies in the range 5° to 15°.  
   
   
       6 . A sealing device according to  claim 3 , wherein said fibers ( 80 ,  90 ) are made of a material having high traction strength, such as, in particular, fibers of aramid resin, carbon, or glass.  
   
   
       7 . A sealing device according to  claim 6 , wherein said fibers ( 80 ,  90 ) are circular in section with a diameter lying in the range about 5 fim to 20 μm, and preferably in the range 10 μm to 12 μm.  
   
   
       8 . A sealing device according to  claim 7 , wherein the packing density of said fibers ( 80 ,  90 ) in a cross-section plane is about 10,000 fibers per mm 2 .  
   
   
       9 . A sealing device according to  claim 1 , wherein each of said filter layers ( 8 ,  9 ) possesses thickness of about 0.4 mm to 0.8 mm.  
   
   
       10 . A sealing device according to  claim 2 , wherein each of said filter layers ( 8 ,  9 ) possesses thickness of about 0.4 mm to 0.8 mm.  
   
   
       11 . A sealing device according to  claim 4 , wherein said fibers ( 80 ,  90 ) are made of a material having high traction strength, such as, in particular, fibers of aramid resin, carbon, or glass.