Abstract:
A method of supporting a tubular within a bore including the steps of at least partially expanding a sleeve into contact with a bore wall to secure the sleeve within the bore, and engaging a portion of the tubular to be supported with the sleeve to provide hanging support for the tubular. In one embodiment, the sleeve is expanded by engagement with the tubular. In another embodiment, the sleeve is initially expanded using a roller expansion tool, with further expansion being achieved by way of engagement of the tubular with the sleeve. 
     An apparatus for supporting a tubular within a bore in one embodiment comprises an expandable sleeve having a first surface and being adapted to be expanded into contact with a bore wall, and a conical portion adapted to be coupled to a tubular, the conical portion having a second surface adapted to engage the first surface of the sleeve.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   This application claims benefit of Great Britain patent application serial number GB 0313664.5, filed Jun. 13, 2003, which is herein incorporated by reference. 
   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to a method and apparatus for supporting a tubular within a bore, and in particular, but not exclusively, to a method and apparatus for supporting liner tubing within a cased subterranean bore. 
   2. Description of the Related Art 
   In the oil and gas exploration and production industry, subterranean bores are drilled from surface to intercept hydrocarbon bearing formations, which often requires bore reaches of as much as 6000 to 10000 metres, for example. In conventional drilling operations, a bore is drilled to a depth of around, for example, 600 metres, when the drill bit and associated drill string is then removed and a string of casing run in and cemented in place to support and seal the bore. Drilling is then recommenced for a further 600 metres, for example, following which a further string of casing is required to support the bore. However, in this case the casing is normally tied back to, and supported from the surface by the wellhead. This procedure is repeated until the bore reaches or nears the required total depth. Once the final drilling stage is completed the drilling string is pulled out of the hole and the final bore section is supported by a liner casing string which does not extend back to the wellhead, but instead terminates downhole and is supported by the previous full string of casing. Thus, special liner hangers are required to allow the liner string to be coupled to and supported by the previous casing string. 
   Conventional liner hangers may be initially coupled to the liner string which is run in hole to the required depth using a setting tool string, and the liner hanger is then set in place within the bore. Typical liner hangers are set in place by mechanical activation of slips or the like, which are brought into engagement with the wall of the bore, thus providing support for the liner. 
   It is among the objects of embodiments of the present invention to provide an improved method and apparatus for providing hanging support for a liner. 
   SUMMARY OF THE INVENTION 
   According to a first aspect of the present invention, there is provided a method of supporting a tubular within a bore, said method comprising the steps of:
         providing a tubular defining a first support surface;   providing an expandable sleeve adapted to be peripherally located around said tubular, said expandable sleeve defining a second support surface;   locating said tubular and expandable sleeve within a bore;   expanding at least a portion of said sleeve into engagement with the bore; and   at least partially supporting the tubular by way of engagement of the first and second support surfaces.       

   It should be understood that the expandable sleeve may be initially located within the bore and at least partially expanded in place before the tubular is located within the bore. Alternatively, the expandable sleeve and the tubular may be located within the bore simultaneously. 
   It should also be understood that the sleeve is expanded into engagement with a bore wall. 
   In one embodiment of the present invention, at least a portion of the sleeve may be initially expanded into engagement with the wall surface of the bore in which the tubular is to be supported by an expansion tool such as a roller expansion tool or an expansion cone or mandrel or the like. In this case the expandable sleeve may be run into the bore on the expansion tool, and at least partially expanded into contact with the bore wall using the expansion tool to provide initial hanging support at the required depth. Subsequently, the tubular may be run into the bore until the first support surface of the tubular engages the second support surface of the sleeve, at which stage weight may be applied to the tubular resulting in further expansion of the sleeve by interaction of the first and second support surfaces, thus providing additional gripping force between the sleeve and the bore wall to support the weight of the tubular. In this regard, the first support surface of the tubular may act as a swage and expands the sleeve by a swage expansion. 
   Advantageously, where expansion is achieved using a roller expansion tool, the expandable sleeve undergoes circumferential yield causing the wall thickness of the sleeve to be reduced. 
   In an alternative embodiment of the present invention, the method may involve the initial step of locating the expandable sleeve peripherally around the tubular in the region of the first support surface. Preferably, the sleeve is initially located below the first support surface of the tubular. Conveniently, the following step may involve running the tubular and the expandable sleeve into the required bore together until the expandable sleeve is located at the required depth. Once the required depth is achieved, relative axial movement of the tubular and expandable sleeve may be initiated to cause engagement of the first and second support surfaces, wherein said engagement results in radial expansion of at least a portion of the sleeve into contact with the wall surface of the bore, providing support for the tubular via the first and second support surfaces. The expansion of the expandable sleeve is thus provided by effectively forcing the tubular through the sleeve or alternatively forcing the sleeve over the tubular. Thus, the first support surface of the tubular may act as a swage to expand the sleeve by a swage expansion process. 
   Preferably, expansion of the sleeve using the first support surface as a swage expander, for example, is achieved by initially restraining the first support surface from movement while moving or forcing the expandable sleeve and thus the second support surface into engagement with the first support surface to initiate expansion of the sleeve. Alternatively, the expandable sleeve may be held stationary while moving the first support surface into engagement with the second support surface of the sleeve. For example, the sleeve may be prevented from travelling further into the bore by a no-go or a profile located on the inner wall surface of the bore, against which no-go or profile the sleeve abuts when run in hole. Alternatively, the sleeve may be held stationary by fixing means associated with the tubular such that the sleeve may be expanded into contact with the bore wall at any required depth. 
   Advantageously, relative movement of the expandable sleeve and the tubular may be achieved by an actuation assembly such as a piston assembly activated by fluid pressure. Alternatively, relative movement may be achieved by a mechanical actuation assembly such as a screw assembly, or by any other suitable actuation assembly. The actuation assembly may be, for example, located below the expandable sleeve and activated to force or push the sleeve towards the first support surface. Alternatively, the actuation assembly may be located above the expandable sleeve and the first support surface of the tubular and activated to force or pull the sleeve towards the first support surface. In this preferred embodiment, the at least one actuation assembly may be coupled to the expandable sleeve by at least one strap or other fixed coupling such as a shear pin or a bolt or the like. 
   Conveniently, where the actuation assembly is located above the first support surface and is coupled to the expandable sleeve by at least one strap, as noted above, said first support surface includes at least one respective channel or recess to accommodate said at least one strap. Thus, the at least one channel or recess will substantially reduce or eliminate any interference by the first support surface. 
   In a preferred embodiment where the expandable sleeve is expanded by interaction of the first and second support members, the method preferably comprises the steps of:
         locating the expandable sleeve and tubular within a bore at the required depth;   restraining said tubular from movement and activating the actuation assembly to pull the sleeve, and thus the second support surface, towards the first support surface of the tubular via at least one connecting strap, thus initiating radial expansion of the sleeve into engagement with the bore wall by engagement of the first and second support surfaces to provide initial hanging support;   imparting weight on the tubular to initiate further radial expansion of the sleeve to increase the grip force between the sleeve and the bore wall; and   exerting an increasing force on the sleeve by the actuation assembly to ensure sufficient expansion of the sleeve to provide support for the tubular via the first and second support surfaces.       

   Preferably, the method further involves inducing tensile failure of the at least one strap to ensure sufficient expansion has been achieved. Thus, the actuation assembly is preferably adapted to exert a force at least equivalent to the tensile strength of the at least one strap. 
   Preferably, the first and second support surfaces of the tubular and sleeve respectively are substantially complementary in shape to allow proper engagement to provide support for the tubular from the expandable sleeve, and to allow expansion of the sleeve by the tubular, where required. 
   Conveniently, the outer diameter described by the first support surface decreases in a direction corresponding to a downward direction with respect to a bore in which the tubular is to be located. Conveniently also, the inner diameter described by the second support surface decreases in a direction corresponding to a downward direction with respect to a bore in which the expandable sleeve is to be located. 
   Preferably, the first support surface of the tubular defines, at least partially, an outer frusto-conical surface portion. Advantageously, the second support surface defines, at least partially, a complementary inner frusto-conical surface portion adapted to be mated or brought into abutment with the outer frusto-conical surface portion of the first support surface upon engagement therewith. Conveniently, where the first and second support surfaces define complementary frusto-conical surface portions, the taper of the surface portions may be less than around 16° from a plane substantially parallel to the longitudinal axis of the tubular. Preferably, the taper of the surface portions is between 3 to 8°. 
   Alternatively, the first support surface of the tubular may define, at least partially, an outer convex surface portion, and the second support surface may define, at least partially, a complementary inner concave portion adapted to be mated or brought into abutment with the outer convex portion of the first support member upon engagement therewith. That is, the first and second support surfaces may be described by a radius of curvature such that the second support surface defines a bowl structure which receives or abuts the complementary shaped first support surface. 
   It should be understood, however, that any complementary shape or configuration of the first and second support surfaces of the tubular and expandable sleeve respectively may be utilised. 
   Advantageously, the expandable sleeve may include a substantially cylindrical portion, which cylindrical portion may be adapted to be at least partially expanded into engagement with a bore wall surface to provide initial hanging support before the remainder of the expandable sleeve is expanded into contact with the bore wall. Preferably, the cylindrical portion is located above the second support surface of the sleeve. Thus, the cylindrical portion, at least once partially expanded, will allow the tubular and first support surface to pass therethrough to engage the second support surface of the sleeve. Alternatively, the cylindrical portion of the expandable sleeve may be located below the second support surface. 
   It should be understood that the term “below” as used herein generally defines relative positions of various components such that a lower component will, in use, be located at a deeper location in the bore. Similarly, it should be understood that the term “above” generally implies that a component is located at a more elevated location in the bore. 
   Advantageously, at least a portion of an outer surface of the expandable sleeve is roughened or otherwise formed or adapted to increase the friction and thus grip between the sleeve and the bore wall. The outer surface of the sleeve may be textured, profiled or may additionally or alternatively include hardened or coarse particles embedded therein or coupled thereto. Such particles may be, for example, carbide or diamond buttons or the like. 
   Conveniently, once the expandable sleeve is expanded and set in place within the bore, and the first and second support surfaces are in engagement such that the tubular is supported by the sleeve, sufficient sealing is provided between the outer surface of the sleeve and the bore wall, and between the first and second support surfaces to prevent the passage of any fluids, such as cement, past the sleeve from an annulus formed between the tubular and the bore. Conveniently, a sealing material may be provided on at least a portion of the outer surface of the sleeve in order to seek to improve sealing between the sleeve and bore wall when the sleeve is expanded. The sealing material may be an elastomer or any other suitable material which is resistant to degradation in a hydrocarbon producing bore environment, for example. The sealing material by comprise a swelling elastomer adapted to swell in the presence of a fluid containing, for example water, drilling mud or lubricant or hydrocarbons. 
   In one embodiment of the present invention, the first support surface may be integrally formed with the tubular. In an alternative embodiment, the first support surface may be provided on a separate component which is subsequently coupled or fixed to the tubular. For example, the first support surface may be provided on a further tubular member which is coupled to the tubular by way of a threaded connection or the like. 
   The bore in which the tubular is to be located and supported may be lined or unlined. For example, the bore may be supported and sealed by casing tubulars cemented in place within the bore such that the expandable sleeve is radially expanded into contact with the inner wall of the casing. 
   Preferably, the tubular to be supported within the bore is a string of liner tubing or the like. 
   Conveniently, once the sleeve has been expanded and the tubular is supported with the bore, the tubular may be lifted from the sleeve to disengage the first and second support surfaces, thus creating a flow passage past the sleeve from an annulus defined between the tubular and the bore wall. This is particularly advantageous in that the flow passage will allow any fluids contained within the annulus to be displaced therefrom during a cementing operation or the like. Additionally, the flow path will allow cement to flow past the sleeve in an up-hole direction to cement the tubular within the bore both above and below the sleeve. 
   Conveniently also, once the sleeve has been expanded and the tubular is supported within the bore, the tubular may be lifted from the sleeve and rotated to assist circulating and evenly distributing cement, for example, within the annulus formed between the tubular and the bore wall during a cementing operation. 
   Thus, the engagement between the first and second support surfaces of the tubular and sleeve respectively is preferably non-permanent. 
   According to a second aspect of the present invention, there is provided a method of supporting a tubular within a bore, said method comprising the steps of:
         providing a tubular defining an outer support surface;   providing an expandable sleeve defining an inner support surface;   running said expandable sleeve into a bore to a first depth and expanding at least a portion of said sleeve into contact with a wall of the bore;   running said tubular into the bore;   engaging the outer support surface of the tubular with the inner support surface of the expandable sleeve; and   supporting the tubular by engagement of the outer and inner support surfaces.       

   Preferably, the method further involves the step of applying weight to the tubular upon engagement of the outer and inner support surfaces to effect further expansion of the sleeve by interaction of the outer and inner support surfaces, thus providing additional gripping force between the sleeve and the bore wall to support the weight of the tubular. In this way, the outer support surface acts as a swage and expands the sleeve by a swage expansion process. 
   According to a third aspect of the present invention, there is provided a method of supporting a tubular within a bore, said method comprising the steps of:
         providing a tubular having an outer support surface;   locating an expandable sleeve peripherally around a portion of the tubular, said sleeve defining an inner support surface;   running said tubular and expandable sleeve into a bore;   initiating relative axial movement between the outer and inner support surfaces of the tubular and the sleeve to expand at least a portion of the sleeve into engagement with a wall of the bore by interaction of the outer and inner support surfaces; and   supporting the tubular via the outer and inner support surfaces.       

   Thus, the outer support surface of the tubular acts as a swage, which in use expands at least a portion of the sleeve into contact with the wall surface of the bore in which the tubular is located. 
   Preferably, the expandable sleeve is moved towards the outer support surface of the tubular while said outer support surface is held stationary. Preferably also, the sleeve is moved in an upward direction relative to the bore in order to initiate expansion of the sleeve. It should be understood that the term “upward” is used herein to define a relative direction and implies that the sleeve is moved in an up-hole direction. 
   According to a fourth aspect of the present invention, there is provided a method of supporting a liner within a cased bore, said method comprising the steps of:
         providing a liner defining a first support surface;   locating an expandable sleeve peripherally located around said liner, said expandable sleeve defining a second support surface;   locating said liner and expandable sleeve within a cased bore;   expanding at least a portion of said sleeve into engagement with a wall of the cased bore; and   supporting the liner by way of engagement of the first and second support surfaces.       

   According to a fifth aspect of the present invention, there is provided an apparatus for supporting a tubular within a bore, said apparatus comprising:
         a first support portion for coupling to a tubular to be supported within a bore, said first support portion including a first support surface;   an expandable second support portion adapted to be expanded into contact with the bore, said second support portion including a second support surface;   wherein said first support portion is adapted to engage the second support portion to provide support for the tubular via the first and second support surfaces.       

   Preferably, the second support portion is adapted to be peripherally located around the tubular requiring support. The second support portion may be a sleeve or the like. 
   In a preferred embodiment of the present invention, the second support portion is adapted to be expanded into engagement with the bore by an expansion tool such as a roller expansion tool or a mandrel or a swage or the like. Alternatively, or additionally, the second support portion may be adapted to be expanded by interaction of the first and second support surfaces, wherein relative movement between the first and second support surfaces results in a swaged expansion of the second support portion. 
   Advantageously, the first support portion may be integrally formed with the tubular. Alternatively, the first support portion may be separately formed and subsequently secured to the tubular at the required location. 
   Preferably, the first support surface defines, at least in part, an outer, substantially frusto-conical surface portion. Preferably also, the second support surface defines, at least in part, an inner, substantially complementary frusto-conical surface portion adapted to be mated with the outer conical surface portion of the first support surface upon engagement therewith. 
   It should be understood that any complementary shape or configuration of the first and second support surfaces may be utilised. 
   Preferably, the tubular to be supported within the bore is a string of liner tubing or the like. 
   According to a sixth aspect of the present invention there is provided a support for use in supporting a tubular within a bore, said support comprising an expandable sleeve defining an inner support surface, wherein said expandable sleeve is adapted to be at least partially expanded into contact with a wall surface of the bore, and the inner support surface is adapted to engage the tubular to provide support therefor. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     These and other aspects of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which: 
       FIGS. 1 and 2  are diagrammatic representations of steps in a method of supporting a tubular within a bore, in accordance with one embodiment of the present invention; 
       FIGS. 3 to 6  are diagrammatic representations of various steps in a method of supporting a tubular within a bore, in accordance with an alternative embodiment of the present invention; 
       FIG. 7  is a cross-sectional perspective view of a sleeve portion used to provide support for a tubular within a bore, in accordance with an embodiment of the present invention; 
       FIG. 8  is a cross-sectional perspective view of a sleeve portion used to provide support for a tubular within a bore, in accordance with an alternative embodiment of the present invention; and 
       FIG. 9  is a diagrammatic representation of a preferred feature of an embodiment of the present invention. 
   

   DETAILED DESCRIPTION 
   Reference is first made to  FIGS. 1 and 2  of the drawings in which there are shown separate stages of a method of supporting or hanging a liner tubing string  10  within a bore  12 , in accordance with an embodiment of the present invention. The bore  12  is a subterranean well bore and is supported and sealed by a casing string  14  which is cemented in place. Referring initially to  FIG. 1 , the liner  10  includes a conical portion  16  which defines a first support surface which is an outer tapered support surface  18 . As shown, the support surface  18  tapers inwardly in a downhole direction, that is, the outer diameter of the conical portion  16  decreases in a downhole direction. Located peripherally around the liner  10  and initially below the conical portion  16 , is a sleeve  20  which defines a second support surface which is an inner conical support surface  22 . The sleeve is manufactured from an expandable material and is complementary to the tapered support surface  18  of the conical portion  16 . For clarity, the sleeve  20  is shown in cross-section. 
   A piston assembly  24  is located above the conical portion  16  of the liner and is coupled to the sleeve  20  by way of a plurality (four in the embodiment shown) of straps  26 . The conical portion  16  includes a corresponding number of channels  28  in the outer surface thereof to accommodate the straps  26 . The piston assembly  24  is actuated by fluid pressure provided from surface. 
   The method of operation and use of the various components identified above will now be described with reference to  FIGS. 1 and 2 . The initial step involves assembling the components in the manner described above to form a liner hanger assembly  30 , which is then run into the bore  12  until the required depth is reached, as shown in  FIG. 1 . The piston assembly  24  is then actuated to pull the sleeve  20  towards the conical portion  16  via the straps  26 , in the direction of arrow A. Continued actuation of the piston assembly  24  will cause engagement of the sleeve inner conical support surface  22  with the conical portion outer tapered support surface  18 , resulting in radial expansion of the sleeve  20 . The sleeve  20  will thus be expanded into contact with the inner wall surface  32  of the bore, as shown in  FIG. 2 , to provide a hanging support for the liner  10 . That is, once the sleeve  20  is expanded into contact with the bore wall  32  by interaction of the outer tapered and inner conical support surfaces  18 ,  22 , the liner  10  will be supported by the sleeve through engagement of said support surfaces  18 ,  22 . 
   In the preferred method of providing hanging support for the liner  10 , the assembly  30  is located in the bore  12  and the piston assembly  24  is actuated while restraining the liner  10  (and thus the conical portion  16 ) from movement, to initially expand the sleeve  20  into contact with the bore wall surface  32 , thus providing initial hanging support. Subsequent to this, weight is applied to the liner  10  to force the conical portion  16  in a downward direction into the bore  12 , to increase the expansion force exerted on the sleeve  20  and thus increasing the grip force produced between the sleeve  20  and the bore wall  32 . The piston assembly  24  is continually actuated to expand the sleeve  20  by interaction with the conical portion  16  until tensile failure of the straps  26  is achieved, as indicated by numeral  34  in  FIG. 2 . At this stage, the sleeve  20  will provide full support for the liner  10  via the complementary support surfaces  18 ,  22 . 
   Once the liner  10  is fully supported by the sleeve  20 , engagement between the sleeve  20  and the bore wall  32 , and the sleeve  20  and the conical portion  16  will provide a fluid tight seal to prevent the upward flow of any fluids, such as cement, past the sleeve  20  from an annulus  36  formed between the casing  14  and the liner  10 . To seek to improve sealing between the sleeve  20  and the bore wall  32 , a sealing element or material  31  is provided on a portion of the outer surface of the sleeve  20 . 
   An alternative method of providing support for a liner within a bore will now be described with reference to  FIGS. 3 to 6  where an expandable sleeve  40  is set in place within a bore  42  to provide hanging support for a liner tubing string  44 . 
   In the embodiment shown, the expandable sleeve  40  includes an upper cylindrical portion  46  and a lower conical portion  48 , and is run into the bore  42 , supported and sealed by casing  50 , to the required depth. As shown in  FIG. 3 , the sleeve  40  is run into the bore  42  on a roller expansion tool  52 , such as that described in WO 00/37766. Upon reaching the required depth, the roller expansion tool  52  is activated to expand the sleeve  40 , and in particular the cylindrical portion  46  of the sleeve  40 , into contact with the bore wall surface  54  in order to retain the sleeve within the bore  42 , as shown in  FIG. 4 . Once the entire cylindrical portion  46 , or at least a substantial portion thereof, is fully expanded into contact with the bore wall  54 , the roller expansion tool  52  is removed from the bore and a string of liner tubing  44  is run in, as shown in  FIG. 5 . The liner  44  includes a conical portion  56  fixed relative thereto and defines an outer tapered surface  58  which corresponds to an inner tapered surface  60  of the sleeve conical portion  48 . Once the conical portion  56  of the liner  10  reaches the depth of the sleeve  40  retained in the bore, engagement of the outer and inner tapered surfaces  58 ,  60  will prevent the liner from travelling further into the bore. 
   In order to ensure that the sleeve  40  will support the liner  44 , the following step involves expanding the remaining portion, that is, the conical portion  48 , of the sleeve  40  into contact with the bore wall surface  54 . This is achieved by applying weight to the liner  44  to force the conical portion  56  of the liner through the sleeve  40 , thus expanding the remaining portion of the sleeve  40  by interaction of the outer and inner tapered portions  58 ,  60 . Thus, the conical portion  56  of the liner  44  acts as a swage expander. In this way, the entire sleeve  40  will be expanded into contact with the bore wall  54  and the liner  44  will be supported by the sleeve by engagement of the outer and inner tapered surfaces  58 ,  60  of the liner conical portion  56  and the sleeve conical portion  48  respectively, as shown in  FIG. 6 . 
   Once the liner  44  is fully supported by the sleeve  40 , engagement between the sleeve  40  and the bore wall surface  54 , and the sleeve  40  and the conical portion  56  of the liner  44  will provide a fluid tight seal to prevent the upward flow of fluid, such as cement, past the sleeve  40  from an annulus  62  formed between the casing  50  and the liner  44 . To seek to improve sealing between the sleeve  40  and the bore wall  52 , a sealing element or material  53  is provided on a portion of the outer surface of the sleeve  40   
   Reference is now made to  FIGS. 7 and 8  in which there is shown cross-sectional perspective views of alternative embodiments of an expandable sleeve for use in supporting a liner within a bore. The sleeve  70  illustrated in  FIG. 7  includes a cylindrical portion  72  formed with a conical portion  74 . As shown, the inner diameter of the conical portion  74  decreases in a downward direction with respect to the orientation of the representation, and defines an inner conical or tapered surface  76 . Thus, the sleeve  70  may be used to support a liner having a portion defining a corresponding tapered surface. The slope or angle B of the tapered surface is, in a preferred embodiment, less then 16°, and advantageously between 3 to 8°. The outer surface  78  of the sleeve  70  is textured to improve the grip between the sleeve and a bore wall surface when the sleeve is expanded into engagement therewith. In the embodiment shown, the outer surface  78  is embedded with diamond or carbide particles or buttons  79 . 
   The sleeve  70  may be used in the method as described with reference to and as shown in  FIGS. 3 to 6 . Additionally, the conical portion  74  alone may be used in the method of  FIGS. 1 and 2 . 
   In the alternative embodiment shown in  FIG. 8 , the sleeve  80  includes an upper cylindrical portion  82  and a lower inner concave portion  84  which defines an inner concave surface  86 . The inner diameter of the lower concave portion  84  generally decreases in a downwards direction with respect to the orientation of the representation. The sleeve  80  of  FIG. 8  is thus adapted for use with a liner having an outer convex surface portion which complements the inner concave surface  86  of the sleeve  80 . Similar to the sleeve  70  of  FIG. 7 , the outer surface  88  of sleeve  80  is embedded with diamond or carbide particles or buttons  89  to improve the grip against a bore wall surface when expanded into contact therewith. 
   The sleeve  80  may be used in the method as described with reference to and as shown in  FIGS. 3 to 6 . Additionally, the lower inner concave portion  84  alone may be used in the method of  FIGS. 1 and 2 . 
   A preferred feature of the present invention will now be described with reference to  FIG. 9  of the drawings in which there is shown a liner string  100  and an expandable sleeve  102  located in a cased bore  104 . The liner  100  includes a conical portion  106  which defines an outer tapered support surface  108 , and the sleeve  102  defines an inner conical support surface  110 , such that the liner  100  may be supported by the sleeve  102  by engagement of the support surfaces  108 ,  110 . Once the liner  100  is supported by the sleeve  102 , as shown, for example, in the embodiments of  FIGS. 2 and 6 , the liner  100  is adapted to be lifted from the sleeve  102  to disengage the support surfaces  108 ,  110  to create a flow passage  112  between the sleeve  102  and the conical portion  106  of the liner  100 . The flow passage  112  allows fluid contained within an annulus  114  below the sleeve  102  to flow past the sleeve in the direction of arrows C. This feature is particularly advantageous, for example, in cementing operations where cement is flowed downwards through the liner  100  and into the annulus  114 . In most cases, drilling fluid and the like will initially be contained within the annulus  114  and the flow passage  112  thus provides a means for this fluid to be displaced upon injection of cement. Once cement is injected into the annulus  114 , the liner  100  is adapted to be reciprocated in longitudinal and rotary directions, as represented by arrows D and E respectively, in order to assist in circulating and evenly distributing the cement within the annulus  114 . 
   It should be understood that the various embodiments of aspects of the present invention described and shown herein may be modified without departing from the scope of the invention. For example, any complementary shape or configuration of the expandable sleeve and the liner may be utilised as would be selected by a person of skill in the art. Additionally, in the embodiment shown in  FIGS. 1 and 2 , the piston assembly  24  may be connected to the sleeve by any suitable number of straps  26 . Furthermore, the piston assembly  24  may be located below the sleeve  22  and thus push the sleeve towards the conical portion  16  of the liner. In the embodiment shown in  FIGS. 3 to 6 , initial expansion of the sleeve may be achieved by any suitable expansion tool or process, and should not be limited to roller expansion. 
   The expandable sleeve may be located at the required depth within the bore and prevented from travelling further into the bore by engagement with a no-go or an internal profile located within the bore on the bore wall surface.