Annular Isolators for Expandable Tubulars in Wellbores

Abstract

The present disclosure addressed apparatus and methods for forming an annular isolator in a borehole after installation of production tubing. Annular seal means are carried in or on production tubing as it is run into a borehole. In conjunction with expansion of the tubing, the seal is deployed to form an annular isolator. An inflatable element carried on the tubing may be inflated with a fluid carried in the tubing and forced into the inflatable element during expansion of the tubing. Reactive chemicals may be carried in the tubing and injected into the annulus to react with each other and ambient fluids to increase in volume and harden into an annular seal. An elastomeric sleeve, ring or band carried on the tubing may be expanded into contact with a borehole wall and may have its radial dimension increased in conjunction with tubing expansion to form an annular isolator.

1 . A system for forming an annular isolator between expandable tubing and a borehole comprising:
 a section of expandable tubing,   a compartment formed in said expandable tubing,   an annular isolator forming material carried in said compartment,   an inflatable member carried on the outer surface of said expandable tubing, and   a flow path from said compartment to said inflatable member   said inflatable member comprises a bladder,   further including a piston adapted for driving said annular isolator forming material from said compartment through said flow path into said bladder,   a compressed spring coupled to said piston, and   a spring restraining means adapted to release said spring upon expansion of said tubing.   
   
   
       2 . A system according to  claim 2 , wherein said restraining means comprises a weld adapted to break upon expansion of said tubing. 
   
   
       3 . A system for forming an annular isolator between tubing and a borehole, comprising:
 a section of expandable tubing,   two annular rings of elastomeric material carried on the outer surface of said tubing, whereby, when said tubing is installed in a borehole and expanded, said rings at least partially block flow of fluids in an annulus between said tubing and the borehole wall,   means for placing an annular isolator forming material between said pair of annular rings,   a band of chemically reactive materials carried on said tubing between said pair of annular rings.   
   
   
       4 . A system according to  claim 3 , wherein said materials are incased in a protective covering preventing chemical reactions from occurring when said tubing is unexpanded and allowing chemical reactions to occur when said tubing is expanded. 
   
   
       5 . A system according to  claim 4 , wherein said materials are two components of an acid base cement which react in the presence of water. 
   
   
       6 . A system according to  claim 5 , wherein said materials are magnesium oxide and monopotassium phosphate. 
   
   
       7 . A system for forming an annular isolator between tubing and a borehole, comprising:
 a section of expandable tubing,   two annular rings of elastomeric material carried on the outer surface of said tubing, whereby, when said tubing is installed in a borehole and expanded, said rings at least partially block flow of fluids in an annulus between said tubing and the borehole wall,   a port from an inner wall of said tubing to an outer wall of said tubing between said two annular rings,   a work string in said tubing having a flow path from the surface location of said borehole to the port.   
   
   
       8 . A system according to  claim 7 , further comprising an expansion tool carried on said work string. 
   
   
       9 . A system for forming an annular isolator between tubing and a borehole comprising:
 a section of tubing,   an elastomeric sleeve carried on the outer wall of said tubing,   said sleeve having a generally cylindrical shape when free of external forces and, in response to axial compression, folding along circumferential lines to take a circumferentially corrugated shape, and   means for compressing said sleeve axially in a borehole.   
   
   
       10 . A system according to  claim 9 , further comprising a plurality of rings of reduced thickness in said sleeve, said rings axially spaced along said sleeve and defining fold points. 
   
   
       11 . A system for forming an annular isolator between tubing and a borehole comprising:
 a section of expandable tubing,   an elastomeric sleeve carried on the outer wall of said tubing,   said sleeve having a generally cylindrical shape having a first axial dimension and a first radial dimension when free of external forces and, in response to axial compressive force, having a second axial dimension shorter than said first axial dimension and a second radial dimension greater than said first radial dimension,   means for applying axial compressive force to said sleeve in a borehole,   wherein said sleeve has a first end and a second end,   a first ring coupled to said sleeve first end and coupled to said tubing,   a second ring coupled to said sleeve second end and slidably coupled to said tubing,   said second ring shaped to slide axially along said tubing and apply compressive force to said sleeve in response to expansion of said tubing by a cone type expansion tool,   an internal sleeve slidably carried within said tubing and coupled to said second ring, said internal sleeve shaped to engage and move with a cone type expansion tool moving through said tubing and to move said second ring axially on said tubing.   
   
   
       12 . A system for forming an annular isolator between tubing and a borehole comprising:
 a section of expandable tubing,   an elastomeric sleeve carried on the outer wall of said tubing,   said sleeve having a generally cylindrical shape having a first axial dimension and a first radial dimension when free of external forces and, in response to axial compressive force, having a second axial dimension shorter than said first axial dimension and a second radial dimension greater than said first radial dimension, and   means for applying axial compressive force to said sleeve in a borehole,   wherein:
 said tubing comprises two sections coupled by a threaded connection, 
 said elastomeric sleeve is carried between said two sections, 
 whereby upon making up of the threaded connection an axial compressive force is applied to said elestomeric sleeve. 
   
   
   
       13 . A system according to  claim 12 , further including:
 a work string adapted to rotatably engage one of said two sections,   whereby upon rotation of said work string, axial compressive force may be applied to said elastomeric sleeve.   
   
   
       14 . A system for forming an annular isolator between tubing and a borehole comprising:
 a section of expandable tubing,   an elastomeric sleeve carried on the outer wall of said tubing,   said sleeve having a generally cylindrical shape having a first axial dimension and a first radial dimension when free of external forces and, in response to axial compressive force, having a second axial dimension shorter than said first axial dimension and a second radial dimension greater than said first radial dimension,   means for applying axial compressive force to said sleeve in a borehole,   a cylinder divided into first and second chambers by a seal adapted to break upon expansion of said tubing,   a first part of two part hypergolic chemical system in said first chamber,   a second part of two part hypergolic chemical system in said second chamber, and   a piston in said cylinder coupled to said sleeve,   whereby upon expansion of said tubing and breaking of said seal, a hypergolic reaction drives said piston to compress said seal.   
   
   
       15 . A system for forming an annular isolator between tubing and a borehole comprising:
 a section of tubing in a borehole,   a conduit in the annulus between said tubing and said borehole, and   an annular isolator filling the space between said tubing, said conduit and said borehole.   
   
   
       16 . A method for forming an annular isolator between tubing and a borehole comprising:
 installing an elastomeric sleeve on an expandable tubing section,   installing the tubing section in a borehole,   increasing the radial dimension of said sleeve, and   expanding said tubing.   
   
   
       17 . A method according to  claim 16 , wherein:
 said sleeve has a first radial dimension when free of external forces,   said step of installing said sleeve on said expandable tubing section comprises applying an axial stretching force to said sleeve to reduce its radial dimension to a second radial dimension smaller than said first radial dimension, and   said step of increasing the radial dimension of said sleeve comprises releasing said axial stretching force.   
   
   
       18 . A method according to  claim 17 , wherein said axial stretching force is released by expansion of said tubing. 
   
   
       19 . A method according to  claim 16 , wherein said step of increasing said radial dimension comprises applying an axial compressive force to said sleeve. 
   
   
       20 . A method according to  claim 19 , wherein said axial compressive force is applied to said sleeve by expansion of said tubing. 
   
   
       21 . A method according to  claim 20 , further comprising installing a ring on said tubing adjacent one end of said elastomeric sleeve, said ring adapted to slide on said tubing in response to movement of a cone type expansion tool through said tubing and to apply axial compressive force to said sleeve. 
   
   
       22 . A method according to  claim 16 , wherein:
 said sleeve has a first radial dimension when free of external forces,   said step of installing said sleeve on said expandable tubing section comprises applying an radial compressive force to said sleeve to reduce its radial dimension to a second radial dimension smaller than said first radial dimension, and   said step of increasing the radial dimension of said sleeve comprises releasing said radial compressive force.   
   
   
       23 . A method according to  claim 22 , wherein said radial compressive force is released by expanding said tubing. 
   
   
       24 . A method for forming an annular isolator between expandable tubing and a borehole comprising:
 attaching an elastomeric sleeve to a section of expandable tubing,   installing the tubing in a borehole,   expanding the tubing with a first expansion tool having a fixed expansion diameter, and   further expanding the tubing in the location of said sleeve.   
   
   
       25 . The method according to  claim 24 , further comprising using a variable expansion cone to further expand the tubing in the location of said sleeve. 
   
   
       26 . The method according to  claim 24 , further comprising applying pressure inside the tubing in the location of said sleeve to further expand said tubing. 
   
   
       27 . The method according to  claim 26 , further comprising applying axial compression to said tubing in the location of said sleeve. 
   
   
       28 . The method according to  claim 24 , further comprising using an expandable bladder at the location of said sleeve to further expand said tubing. 
   
   
       29 . The method according to  claim 24 , further comprising swelling the elastomeric sleeve in the borehole. 
   
   
       30 . The method according to  claim 29 , further comprising swelling the elastomeric sleeve by exposing the elastomeric sleeve to fluid in the borehole.