Patent Publication Number: US-9840878-B2

Title: Connector apparatus

Description:
The present invention provides an apparatus and a method for connecting tubular members in a wellbore and in particular provides an apparatus and a method for sealing and/or securing a first (inner) tubular to a second (outer) tubular in a wellbore and thereby providing an annular seal between the first and second tubular members. 
     In wellbore drilling and completion, various tubular elements (also typically referred to in the industry as “tubulars”) need to be connected to each other. For example, in well completions, a number of tubulars may have to be connected end to end in order to form a string of tubulars such as a casing string or liner string to line the wellbore to the required depth. In some cases, one tubular has to be set inside another tubular by increasing the diameter of the inner tubular until it contacts the inner wall of the outer tubular and creates an interference fit therewith. The connection between the tubulars very often must be capable of withstanding axial loads (i.e. secured). The connection should also be fluid tight to provide an annular barrier between the tubulars (i.e. sealed) to prevent fluid passage between the internal bore of the outer tubular and the exterior of the inner tubular. 
     One prior art arrangement for connecting tubular members in a wellbore is described in WO2011/048426 A2 and includes a metal to metal seal between first and second tubular members A, B in a cased wellbore, as shown in  FIGS. 1 and 2  of the present application. The second (lower) tubular member B includes an upper end portion C which has a greater inner diameter than the outer diameter of a lower end portion D of the first (upper) tubular member A. Circumferential recesses or grooves E are formed on the inner surface or bore of the upper end portion C of the second (lower) tubular member B. In order to form the seal, firstly, the lower end portion D of the first tubular member A is located within the upper end portion C of the second tubular member B. Next, a hydraulic expansion tool F is lowered from surface inside the first tubular member A to the intended location of the seal (see  FIG. 2  of the present application). The tool F seals off a chamber G between a pair of axially spaced apart seals H. Actuation of the hydraulic expansion tool F causes chamber G to be filled with fluid under high pressure, and this high pressure fluid acts on the inner surface or bore of the lower end portion D of the first tubular member A to first elastically and then plastically expand so that the lower end portion D expands radially outwardly along a length bounded by the seals H into the recesses E on the inner bore of the second tubular member B such that circumferential protrusions I or ridges are formed on the outside of the lower end portion D of the first tubular portion A. These protrusions I are received in the recesses E until a seal is formed between the first and second tubular members A, B. 
     In this way, a liner tieback is formed. A similar technique is used to connect an overshot device with a tubular downhole, e.g. casing or liner, in fishing operations, to engage an inner bore surface of the overshot device with the outer surface of the tubular, to allow jarring and retrieval of the tubular. This technique also provides a casing reconnect. 
     A known problem associated with the above described arrangement is that well fluid present at the interface between the tubular members A, B may become trapped in the recesses E which can lead to the formation of hydraulic lock which is potentially damaging to the tubular members. Additionally, when the pressure used to morph the first tubular member A to the second tubular member B is released, the trapped fluid pressure within the recesses E may cause separation of the members A, B causing the metal to metal seal created at the contact point  3  (see  FIG. 3 ) to be lost as the first member A is forced away from the second member B. 
     It is an object of the present invention to provide a connector apparatus for sealingly connecting to a tubular member in a wellbore which obviates or mitigates at least some of the disadvantages of the prior art. 
     According to a first aspect of the invention there is provided a connector apparatus for sealingly connecting to a tubular member in a wellbore, the connector apparatus comprising: 
     a substantially cylindrical body having a receiving section adapted to receive therein at least one portion of the tubular member for permitting expansion of the said at least one portion radially outwardly against one or more circumferential recesses on an inner surface of the receiving section until one or more joints are formed between the said at least one portion and the receiving section; wherein, a resilient member protrudes from a side wall of at least one of said recesses, the resilient member being acted on by the at least one portion during expansion and maintaining sealing contact to the at least one portion after expansion. 
     In this way, when the pressure is released after expansion of the tubular member, the resilient member will move with the tubular member to ensure a seal is maintained between the connector apparatus and the tubular member. 
     Preferably, the resilient member is entirely contained within the recess. In this way, the resilient member does not interfere with the tubular member being located in the receiving section. 
     Preferably, there are two resilient members, oppositely arranged across the recess, each protruding from an opposing side wall. In this way, a seal is maintained at either side of the recess. 
     Preferably, the resilient member is an annular ring and is coaxial with the circumferentially arranged recess. In this way, a seal is maintained around the entire circumference of the connector apparatus. 
     Preferably, the resilient member has an upper surface and a lower surface, the lower surface facing a base of the recess. In this way, the lower surface provides a surface for the trapped pressure to act against and help maintain the seal. 
     Preferably, the resilient member includes a spur, located on the upper surface. More preferably the spur extends circumferentially around the resilient member. In this way, point contact is achieved with the tubular member. 
     In an embodiment, the resilient member is formed integrally with the receiving section. In this way, the resilient member can be machined in the receiving section when the recess is machined. 
     In a further embodiment, the resilient member is a metal ring located within the recess. In this way, resilient members can be added when required and the complexity and cost of machining the receiving section. Preferably, the metal ring includes a support base, the base having a height substantially the same as the height of the side wall of the recess. In this way, the metal ring is supported in the recess and the position of the protruding resilient member is fixed relative to the base of the recess. 
     Preferably, a plurality of recesses is linearly arranged along the inner surface of the receiving section and at least one recess includes at least one resilient member. More preferably, a recess includes two opposing resilient members. Alternatively, there are a pair of neighbouring recesses with a resilient member on each side wall of the adjoining rim between the recesses. 
     A resilient member may be located on a common side wall of a plurality of the recesses. In this way, a unidirectional seal is provided along the connector apparatus at multiple unidirectional sealing points. Such a unidirectional arrangement allows any pressure build up between resilient members facing the same direction to be expelled as the upper resilient members flex outwards to let the pressurised fluid out. 
     In an embodiment, there are a pair of neighbouring recesses with a resilient member on each side wall of the adjoining rim between the grooves, with at least one recess to the right including a resilient member on its left side wall and at least one recess to the left including a resilient member on its right side wall. In this way, pressure can be expelled through the opposing directed resilient members away from the centre rim. 
     Preferably, where a recess includes one resilient member the opposing side wall has a radius with the inner surface of the tubular member. 
     Preferably, the resilient member is formed of metal so that a metal to metal seal is formed. 
     Preferably, the one or more created joints are either sealed or secured connections or, more preferably, are both sealed and secured joints. The so formed joint created between the connector apparatus and the tubular member has the ability to withstand axial loads and fluid pressures acting between the connector apparatus and the tubular member. The joint preferably creates both a mechanical fixing between the two tubular members and also a hermetic seal between the connector apparatus and the tubular member. Preferably, the joint is formed as a result of initially elastic and then plastic deformation of the material of at least the said at least one portion and, preferably also the receiving section of the connector apparatus. 
     The outward expansion may be achieved, for example, by application of radial outward pressure or force to side walls of the said at least one portion of the tubular member within an inner bore of the said at least one portion. 
     In an embodiment, a fluid exclusion device is located in one or more recesses. The fluid exclusion device may be provided having an annular configuration, e.g. in the form of a ring. The fluid exclusion device may comprise a fluid exclusion material, which may comprise a crushable medium, such as, for example closed cell foam, such as, for example, metal foam or syntactic foam, placed in the recess in order to prevent fluid from filling the recess but being collapsible under the pressure of the at least one portion so as to allow a protrusion of the at least one portion to enter the recess. The fluid exclusion device is also preferably capable of taking in some fluid whilst being collapsed thereby further minimising the risk of occurrence of a hydraulic lock. Such fluid may be present about the fluid exclusion device prior to the fluid exclusion device being collapsed or may be displaced towards the fluid exclusion device during expansion of the said at least one portion of the tubular member. Alternatively or additionally, the fluid exclusion device comprises a collapsible ring, such as, for example, a hollow ring, in the or each recess, the ring being configured to collapse when the ring experiences certain pressure. The collapsible ring works in a manner similar to the fluid exclusion foam, i.e. by preventing fluid from entering the recess when the ring is intact whilst collapsing under the force of the circumferential protrusion of the said at least one portion of the second tubular member. A collapsible ring can function at higher temperatures and pressures than those withstandable by foam. Also, an appropriately selected collapsible ring may be capable of accommodating greater fluid volume than foam. 
     In a further embodiment, a port may be located through the base of one or more recesses. The port provides a fluid exit path to relieve pressure from within the recess during morphing by evacuating it to the outside of the connector apparatus. 
     Optionally, one or more rims between adjacent recesses may include a bypass channel. The bypass channel advantageously allows fluid under pressure to travel from one recess to a neighbouring recess. The bypass channel may be a slot machined on the surface of the rim. A fluid bypass channel may also be located along the inner surface of a distal recess to allow fluid to escape from an end of the connector apparatus. In this way hydraulic lock is prevented. 
     The said at least one portion of the tubular member can be expanded by an appropriate tool, such as for example a conventional prior art hydraulic expansion tool, a cone displacement tool, rollers, or any other tool capable of increasing the inner diameter of the said at least one portion. 
     The connector apparatus could be any sort of tubing used downhole, for example, an overshot device for fishing operations, or indeed casing, liner, tieback liner or production tubing, etc. which needs to be fitted over an outer surface of another smaller diameter tubing for example, as a liner tieback or casing reconnect. 
     Similarly, the tubular member can comprise any sort of tubing, tubular, conduit or pipe used downhole e.g. liner for a liner tieback and casing for a casing reconnect. 
     According to a second aspect of the invention there is provided a method of connecting tubular members in a wellbore, the method comprising the steps of: 
     a) providing a connector apparatus according to the first aspect; 
     b) placing the said at least one portion within the receiving section of the connector apparatus; 
     c) expanding the said at least one portion radially outwardly against the receiving section until one or more joints are formed between the said at least one portion and the receiving section; 
     d) acting on the resilient member by the at least one portion during expansion; and 
     e) acting on the at least one portion by the resilient member following expansion to maintain sealing contact between the resilient member and the at least one portion after expansion. 
     In this way, when the pressure is released after expansion of the tubular member, the resilient member will move with the tubular member to ensure a seal is maintained between the connector apparatus and the tubular member. 
     Preferably, the method includes the step of using trapped fluid pressure to act upon a lower surface of the resilient member to assist in maintaining sealing contact between the resilient member and the at least one portion after expansion. 
     Preferably, the method includes the step of providing multiple unidirectional sealing points along the connector apparatus. 
     Preferably, the method includes the step of directing pressurised fluid out the at least one recess. This step may be by directing fluid through a port in the recess to the outside of the connector apparatus. Alternatively or additionally the step may be by directing fluid between neighbouring recesses. 
     In the description that follows, the drawings are not necessarily to scale. Certain features of the invention may be shown exaggerated in scale or in somewhat schematic form, and some details of conventional elements may not be shown in the interest of clarity and conciseness. It is to be fully recognized that the different teachings of the embodiments discussed below may be employed separately or in any suitable combination to produce the desired results. 
     Accordingly, the drawings and descriptions are to be regarded as illustrative in nature, and not as restrictive. Furthermore, the terminology and phraseology used herein is solely used for descriptive purposes and should not be construed as limiting in scope. Language such as “including,” “comprising,” “having,” “containing,” or “involving,” and variations thereof, is intended to be broad and encompass the subject matter listed thereafter, equivalents, and additional subject matter not recited, and is not intended to exclude other additives, components, integers or steps. Likewise, the term “comprising” is considered synonymous with the terms “including” or “containing” for applicable legal purposes. 
     All numerical values in this disclosure are understood as being modified by “about”. All singular forms of elements, or any other components described herein including (without limitations) components of the apparatus are understood to include plural forms thereof. All positional terms such as ‘up’ and ‘down’, ‘left’ and ‘right’ are relative and apply equally in opposite and in any direction. 
    
    
     
       Embodiments 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 sectional side views of stages of a prior art method of connecting tubular members and therefore do not form part of the present invention; 
         FIG. 3  is an exploded view of part of the sectional side view of the connection in  FIG. 2  and therefore does not form part of the present invention; 
         FIG. 4  is a schematic illustration of a sectional side view of an arrangement for connecting tubular members according to an embodiment of the present invention; 
         FIGS. 5 and 6  are schematic illustrations of a sectional side view of details of a connecting apparatus of an arrangement of  FIG. 4 ; 
         FIG. 7  is a schematic illustration of a sectional side view of a detail of the arrangement for connecting tubular members of  FIG. 4 ; 
         FIG. 8  is a schematic illustration of a sectional side view of a detail of an arrangement for connecting tubular members according to another embodiment of the present invention; 
         FIG. 9  is a schematic illustration of a sectional side view of a detail of an arrangement for connecting tubular members according to another embodiment of the present invention; 
         FIG. 10  is a schematic illustration of a sectional side view of a detail of an arrangement for connecting tubular members according to another embodiment of the present invention; 
         FIGS. 11 and 12  are schematic illustrations of a sectional side view of a detail of an arrangement for connecting tubular members according to another embodiment of the present invention; 
         FIGS. 13 and 14  are schematic illustrations of a sectional side view of a detail of an arrangement for connecting tubular members according to another embodiment of the present invention; 
         FIG. 15  is a schematic illustration of a sectional side view of a detail of an arrangement for connecting tubular members according to another embodiment of the present invention; 
         FIG. 16  is a schematic illustration of a sectional side view of a detail of an arrangement for connecting tubular members according to another embodiment of the present invention; and 
         FIG. 17  is a schematic illustration of a sectional side view of a detail of an arrangement for connecting tubular members according to another embodiment of the present invention. 
     
    
    
     Referring initially to  FIG. 4  there is provided a connector apparatus generally indicated by reference numeral  10  for providing a sealed connection to a first tubular member  12  according to an embodiment of the present invention. 
     The first tubular member  12  has a substantially cylindrical body having a bore  14  therethrough providing an inner surface  16  with a first diameter  18  and an outer surface  10  with a second diameter  22  along the majority of its length (not shown). The first tubular member  12  is of metal construction and has dimensions typical of tubulars round in the oil and gas industry as used in tubing strings, casings and liners. The first tubular member  12  has a first end  24  with an annular end face  26  which is substantially perpendicular to the longitudinal axis of the bore  27 . 
     In this embodiment, a second tubular member  32  has a substantially cylindrical body  34  having a bore  36  therethrough providing an inner surface  38  with an inner diameter  40  along the majority of its length (not shown). The inner diameter  40  is the narrowest section of the tubular member  32 . The second tubular member body  34  is of metal construction and has dimensions typical of tubulars round in the oil and gas industry as used in tubing strings, casings and liners. The second tubular member  32  has a first end  42  with an annular face  44  which is substantially perpendicular to the longitudinal axis  46  of the bore  36 . 
     The connector apparatus  10  is integrally formed with, and will be described with reference to, a first end  42  of the second tubular member  32 . On the inner surface  38  of the length of connector apparatus arranged at the first end  42  of the second tubular member  32  there is provided a series of profiled sections  50  and  52 . Each profiled section  50  and  52  is a shape machined into the inner surface  38 . The shape of each of  50  and  52  are each entirely circumferential in that, a cross sectional view, as shown in  FIG. 5  for profiled section  50  and  52  for every cross-section around the tubular  32 . 
     Profile section  50  provides circumferential groove  54 . The grooves  54  are rectangular cut outs forming a complete annular ring. The grooves  54 , when formed adjacent one another, are equidistantly spaced with a rim  56 , which has a rectangular profiled, is located between the grooves  54 . The rim  56  may be considered as a circumferential band, bead or protrusion facing the bore  34 . While three adjacent grooves  54  are arranged adjacent one another in the present embodiment, it will be understood that any number of grooves may be arranged adjacent one another in this arrangement. In this embodiment, a width of each groove  54  is greater than a corresponding width of each rim  56  although any relationship can be used. 
     Profile section  52  provides circumferential groove  60  which forms a complete annular ring. The groove  60  is undercut into the body  34  of second tubular  32  to create recesses  61  such that the distal end  57  of each rim  58 , which is formed adjacent groove  60  is provided with a projection, or lug  63 . Each lug  63  extends from rim  58  toward the opposing lug  63  in parallel to the longitudinal axis of the bore  36 . In this embodiment, a width of each groove  60  is greater than a corresponding width of each rim  58  and projection  63  although any relationship can be used. 
     In  FIG. 6 , a portion of a profiled section  52  and rim  58  is shown in more detail. The recess  61  is formed by undercutting the body  34  of the inner surface  38  below thus leaving projection  63  at the distal end  57  of rim  58  where it extends in parallel to the longitudinal axis of bore  36 . The projection  63  is machined in such a way that the underside surface  66  tapered towards the inner surface  38  of the bore  36  as the lug progresses in its projection to form the distal end  67  of the lug  63  and is formed so as to be operable to act as a resilient member which can be elastically deformed upon application of radial pressure. Distal end  67  may be rounded. 
     In use, the first end  24  of the first tubular member  12  is inserted into the first end  42  of the second tubular member  32  until the annular end face  26  of the first end  24  extends beyond the profiled sections  50 ,  52  of connector apparatus  10  such that the profiled sections  50 ,  52  are co-axially arranged around the outer surface  20  of the first tubular member  12 . This arrangement is shown in  FIG. 4 . A metal to metal seal is created between the outer surface  20  of the first end  24  of the first tubular member  12  and the profiled sections  50  of the connector apparatus  10  arranged at the first end  42  of the second tubular member  32 . This is achieved by applying force to the inner surface  16  at the first end  24  of the tubular member  12 . 
     The seal may be created by use of a hydraulic tool (not shown). A detailed description of the operation of such a hydraulic tool is described in GB2398312 in relation to the packer too  112  shown in  FIG. 27  of GB2398312 with suitable modifications thereto, where the seal means  92  could be provided by suitably modified seal assemblies  214 ,  215  of GB2398312, the disclosure of which is incorporated herein by reference. The entire disclosure of GB 2398312 is incorporated herein by reference. 
     The tool is inserted into the tubulars  12 ,  32  and located within the bore  27  of the first tubular member  12 . Elastomeric seals (not shown) are arranged on the tool to straddle the grooves  50 ,  52  and lie over the inner surface  16  of the tubular member  12 . When in position, the elastomeric seals are energised so that they expand radially outwardly and create a seal between the outer surface of the tool body and the inner surface  16  of the first tubular member  12 . With the seals energised, a chamber is created which is bounded by the outer surface of the tool, the inner surface  16  and the elastomeric seals. Hydraulic fluid is then pumped through the tool body so that it exits a port and enters the chamber. Once the chamber is filled, continued pumping forces the outer surface  20  of the first end  24  of the tubular member  12  to move radially outwardly by the use of fluid pressure acting directly on the inner surface  16  between the elastomeric seals. Sufficient hydraulic fluid pressure is applied to move the outer surface  20  of the first end  14  of the tubular member  12  radially outwards and cause the tubular member  12  to morph itself onto the inner surface  38  of the first end  42  of the second tubular member  32 . This is as per the prior art described with reference to  FIGS. 1 and 2 . 
     During the morphing process, the first tubular member  12  will undergo elastic expansion filling, or at least partially filing the grooves  50 ,  52 . The lugs  63  will be acted upon by the outer surface of the morphing first tubular  12  and will deflect inward towards the recess  52  within their elastic limit giving an improved metal to metal sealing contact between the lugs  63  and the outer surface  20  as is shown in  FIG. 7  with no intermediary connector member required. Continued expansion will cause the tubular member  12  to undergo plastic deformation. Sufficient pressure may be applied to also cause the first end  42  of the second tubular member  32  to elastically deform. When the pressure is released the first end  42  will return to its original dimensions and create a seal against the deformed end  24  of the tubular member  12 . Similarly, upon release of the hydraulic fluid pressure if any reduction in expanded dimensions of inner tubular  12  occurs, the deflected lugs  63  will also spring back maintaining a sealing contact pressure. 
     During the morphing process, the outer surface  20  of the end  24  of the first tubular member  12  will take up the shape of the inner surface  38  of the first end  40  of the second tubular member  32 . A metal to metal seal is preferentially achieved between the first tubular member  12  and the second tubular member  32  at the edges of the grooves  50 ,  52 . At each groove  50 , there are two points for a seal, so for several grooves there are multiple sealing points. At each groove  52 , the lugs  63  provide an extended surface area over which a resilient seal occurs as well as the points at the distal ends  67  around which the tubular member  12  bends when it is morphed into groove  52 . The grooves  50 ,  52  provide for vertical loading when the tubular members  12 ,  32  are arranged for insertion into the well bore (not shown) should assembly of the tubulars  12 ,  32  occur prior to insertion into a well bore. The lugs  63  at grooves  52  also provide for improved continued sealing being achieved should axial loading occur at the joint. Once the connector apparatus  10  has been activated, the resilient seal provided by the lugs  63  protruding in an opposing direction maintains a seal at either side of the recess  50  which is maintained around the entire circumference of the connector apparatus  10 . Furthermore, should any fluid have become trapped in recess  52  during the morphing process then, upon release of the hydraulic morphing pressure, residual trapped fluid pressure will act upon the underside  66  of the lug  63  thus helping to maintain the metal to metal contact seal. 
     With the joint between the first tubular member  12  and the second tubular member  32  made, the elastomeric seals on the tool are de-energised so that they come away from the surface  20 . The tool can then be removed from the tubular members  12 ,  32 . 
     In  FIG. 8 , a detail of connector apparatus  10  is shown according to another embodiment of the present invention. The resilient seal lug  63  is shown to be provided with a projection, or spur,  70  which extends circumferentially around the resilient member  63 . In use, as morphing hydraulic pressure is applied to first tubular member  12 , the spur  70  acts as a point contact around which the outer surface  20  of the first tubular member  12  can deform thus enhancing the resilient seal achieved. 
     In  FIG. 9 , a detail of connector apparatus  10  is shown according to another embodiment of the present invention. The body  34  of second tubular member  32  has circumferential groove  54  milled to form a complete annular ring having a profile section  50 . The section  50  has sides  71  milled perpendicularly to the longitudinal axis  46  of the bore  36 . Resilient seal members  72  are ring members, formed of metal construction, which are located in recess  50  such that the upper surface  73  of lugs  63  is in parallel with rim surfaces  57 . The resilient seal member  72  is formed of metal and is provided with a side support  76  which, in use abuts against side  71  of profile section  50  and enables the protruding lug  63  to be held in position within the recess  50 . The resilient seal  72  can be further provided with a base (not shown) which lies in parallel along the base  77  of the recess  50  and connects to the opposing resilient seal  72  to further facilitate the positioning of the resilient seal members within the recess  50 . In use, the resilient seal will be actuated such that the lugs  63  elastically deform to provide an enhanced seal as previously described above. 
       FIG. 10  illustrates an embodiment of the present invention wherein the first end  24   a  of a first tubular member  12   a  and the first end  24   b  of another first tubular member  12   b , are each inserted into opposing ends  82   a ,  82   b  respectively of a connection tubular member  80  wherein each end  82   a ,  82   b  of the tubular member  80  is provided with connector apparatus  10 . The connection tubular member  80  is a dual coupling system for connecting tubular members  12   a ,  12   b . Connection tubular member  80  can, advantageously be of a shorter length that tubular members  12   a ,  12   b  so that it is easier to machine the profiled sections  50  and, if included,  52 , on the inner surface  84  thereof. The connector  80  may also be formed of a different material to tubular members  12   a ,  12   b  which can resist the outwardly applied radial force better than the material of the tubular members  12   a ,  12   b.    
     Reference is now made to  FIGS. 11 and 12  of the drawings which illustrates a detail of the connector apparatus, generally indicated by reference numeral  110 , for providing a connection between a first tubular member  112  and a second tubular member  132  according to another embodiment of the present invention. Like parts to those of  FIGS. 4 to 10  have been given the same reference numerals with the addition of ‘100’ to aid clarity.  FIG. 11  shows a details of connector apparatus  110  for forming a metal to metal coupling between a first tubular member  112  and a second tubular member  114 , similar to the coupling arrangement of  FIG. 4 , wherein the first tubular member is inserted into the second tubular member  132  end  146  at which connector apparatus  110  is located such that it is able to be connected as is shown in  FIG. 12 . 
     In the embodiment of  FIG. 11 , the second tubular member  132  is provided with grooves  150  having rims  154  therebetween with one groove  150  between two rims  154  shown. The depth of groove  150  is approximately half the thickness of the wall  133  of the second tubular member  132 . The side walls  171  of groove  150  and resilient seal member  180  are inserted into groove  150  along with fluid exclusion means  182 . 
     The resilient seal member  180 , formed of a metallic material, each comprises a support  176 , one face  176   a  of which is suitable to abut in parallel against recess wall  171 . From support face  176   b , two lugs project: lug  163  which juts from the distal end  175  of the seal member  180 , and lug  184  which projects from around the midpoint of faced  176   b . Lug  163  tapers from the point of projection to the distal tip  167  of the lug  163 . The upper surface  173  of lug  163  is angled slightly away from recess  152  without projecting beyond rim  154  into bore  146 . A spur  170  extends from the upper surface  173  of resilient seal member  180  and the projection  170  will act as a metal seal ring in use as described with reference to the metal seal ring  70  of  FIG. 8 . 
     Lug  184  projects into recess  150  and is used to hold the fluid exclusion means  182  in position. The recess  150  is further provided with fluid exclusion means  182 . Fluid exclusion means are operable to exclude fluid from the interface between groove  150  and the outer surface  124  of first tubular  112  to minimize the occurrence of a hydraulic lock during the morphing process. In the presently described embodiment, the fluid exclusion means  182  comprises three fluid exclusion rings  182   a, b, c  each of which can be made of a fluid exclusion material, for example closed cell foam such as metal foam or syntactic foam although it will be appreciated that other suitable materials may be used. 
     Fluid exclusion ring  182   b  is an annular ring with a substantially rectangular or square profile. Fluid exclusion rings  182   a, c  each have a substantially rectangular profile which is provided with a lug projection  183   a, c  respectively which extends outwards from the ring  182   a, c . The fluid exclusion rings  182   a, b, c  are placed in the recess  150  with ring  182   b  placed centrally and rings  182   a, c  placed on either side of ring  182   b  such that lug projections  183   a, c  extend in opposing directions towards the walls  171  of recess  150  such that the projections  183   a, c  are retained in placed within recess  159  below lugs  184  and a void  186  is created between lugs  163 ,  184  and fluid exclusion means  182 . 
     The rings  182   a, b, c  may be made of the same, or of differing, fluid exclusion materials. The fluid exclusion rings  182   a, b, c  are placed in the recess  150  between resilient seal members  180  in order to prevent fluid from entering the recess  150 . The fluid exclusion rings  182   a, b, c  are crushable or collapsible under external pressure. The fluid exclusion rings are preferably capable of taking in some fluid whilst being collapsed thereby further minimising the risk of occurrence of a hydraulic lock. Such fluid may be present around the fluid exclusion rings  182   a, b, c  prior to being collapsed or may be displaced towards the fluid exclusion rings  182   a, b, c  during expansion of the first tubular member  112 . However, fluid  188  may be present in voids  186  during the morphing process. 
     In use the lugs  163  provide an extended surface area over which a resilient seal occurs as well as the points at the distal ends  67  around which the tubular member  112  bends when it is morphed into groove  150 . Once the connector apparatus  110  has been activated, the resilient seal provided by the lugs  163  protruding in an opposing direction maintains a seal at either side of the recess  150  which is maintained around the entire circumference of the connector apparatus  110 . Furthermore, the fluid  188 , having become trapped in void  186  during the morphing process is subject to fluid pressure and, upon release of the hydraulic morphing pressure, will act upon the underside  166  of the lug  163  thus helping to maintain the metal to metal contact seal. 
     The connection joint formed between the first tubular member  112  and second tubular member  132  by connector arrangement  110  has the ability to withstand axial loads and fluid pressures acting between the first tubular member  112  and the second tubular member  132 . The joint creates both a mechanical fixing between the two tubular members  112 ,  132  and a hermetic seal between the tubular members  112 ,  132 . 
     In use, the first end  124  of the first tubular member  112  is inserted into the first end  142  of the second tubular member  132  until the annular end face  126  of the first end  124  extends beyond the profiled sections  150  of connector apparatus. A metal to metal seal is created between the outer surface  120  of the first end  124  of the first tubular member  112  and the profiled sections  150  and resilient members  180  of the connector apparatus  10  arranged at the first end  142  of the second tubular member  132 . This is achieved by applying force to the inner surface  16  at the first end  24  of the tubular member  12  using a hydraulic tool as is described above. 
     Reference is now made to  FIGS. 13 and 14  of the drawings which illustrates a detail of the connector apparatus, generally indicated by reference numeral  210 , for providing a connection between a first tubular member  212  and a second tubular member  232  according to another embodiment of the present invention. Like parts to those of  FIGS. 4 to 10  have been given the same reference numerals with the addition of ‘200’ to aid clarity. 
       FIG. 13  shows a details of connector apparatus  210  for forming a metal to metal coupling between a first tubular member  212  and a second tubular member  232 , similar to the coupling arrangement of  FIG. 4 , wherein the first tubular member is inserted into the second tubular member end  242  at which connector apparatus  210  is located such that it is able to be connected as is shown in  FIG. 14 . 
     In the embodiment of  FIG. 13 , the second tubular member  232  is provided with grooves  250  having rims  256  therebetween. The side wall  271   a  on the right hand or upper side of groove  250  includes a resilient seal member  263  as described hereinbefore with reference to  FIGS. 4 to 10 . This provides a set of resilient seal members  263  all facing the same direction, that is, towards the left or downwards. The opposing side wall  171   b  is rounded being provided with a radius to meet the rim  256 . 
     When the first tubular member  212  and a second tubular member  232  are morphed together as described hereinbefore and shown in  FIG. 14 , each resilient seal member  263  provides a sealing point between the tubular members  212 ,  232 . The radius provides a sealing section at each groove and assists in pushing fluid under the resilient member  263  to thereby maintain the sealing point contact when the morphing pressure is released. 
     A further embodiment of a connector apparatus  310  is shown in  FIG. 15 . Connector apparatus  310  is integrally formed with, and will be described with reference to, a first end  342  of the second tubular member  332 . Like parts to those of  FIGS. 4 to 10  have been given the same reference numerals with the addition of ‘300’ to aid clarity. 
     On the inner surface  338  of the length of connector apparatus  310  arranged at the first end  342  of the second tubular member  332  there is provided a series of profiled sections  350 ,  352 ,  354 . Each profiled section  350 ,  352 ,  354  is a shape machined into the inner surface  338 . The shape of each of  350 ,  352 ,  354  are each entirely circumferential in that, a cross sectional view, as shown in  FIG. 15  for profiled section  350 ,  352 ,  354  for every cross-section around the tubular  332 . 
     Profiled sections  354  provide circumferential grooves  360 . The grooves  360  are rectangular cut outs forming a complete annular ring. The grooves  360 , when formed adjacent one another, are equidistantly spaced with a rim  356 , which has a rectangular profiled, is located between the grooves  360 . The rim  356  may be considered as a circumferential band, bead or protrusion facing the bore. While two adjacent grooves  360  are arranged adjacent one another in the present embodiment, it will be understood that any number of grooves may be arranged adjacent one another in this arrangement. In this embodiment, a width of each groove  360  is greater than a corresponding width of each rim  356  although any relationship can be used. 
     Profile sections  352 ,  354  provide circumferential grooves  361 ,  365  which form complete annular rings. The grooves  361 ,  365  both include a single resilient member or lug  363 . Lug  363  is described hereinbefore with reference to  FIGS. 4-13 . Each lug  363  is arranged on opposing side walls  371   b ,  371   a  of the rim  356  located between the grooves  361 ,  365 . As such the lugs  363  each provide a unidirectional seal but in opposite directions. This gives bi-directional metal to metal sealing to the connection. 
     Grooves  360 ,  361  also include a port  90  being an aperture between the base  377  of the groove  360 ,  361  and the outer surface  92  of the second tubular member  332 . Groove  365  includes a slot  94  along the inner surface  338  connecting the groove  365  with the bore above the upper end  326  of the first tubular member  312 . 
     In use, first tubular member  312  is inserted within the connector apparatus  310  of second tubular member  332  to form a casing reconnect or liner tieback, for example. The upper end  326  of the first tubular member  312  is positioned at the slot  94 . The first tubular member  312  is morphed against the inner surface  338  of the second tubular member  332  so that it enters the grooves  360 ,  361 ,  365  making metal to metal sealing contact with the edges of the rims  356  and the lugs  363 . Fluid trapped in the grooves  360 ,  361  is forced out of the ports  90  so as to allow the first tubular member  312  to enter the grooves  360 ,  361  without risk of hydraulic lock. Fluid within groove  365  is forced through the slot  94  into the bore of the tubular members  312 ,  332 . When the morphing pressure is released the lugs  363  will by their resilient nature bend inwards to maintain sealing contact with the first tubular member  312 . The morphed connection can bear axial loading due to the corrugation of the first tubular member  312  into the grooves  360 ,  361 ,  365  of the second tubular member  332 . It is noted that this connection is achieved without requiring the use of a fluid exclusion means such as syntactic foam in the grooves  360 ,  361 ,  365 . 
     A further embodiment of a connector apparatus  410  is illustrated in  FIG. 16 . Like parts to those of  FIGS. 4 to 10  have been given the same reference numerals with the addition of ‘400’ to aid clarity. In this arrangement there are four grooves  465   a, b ,  461   a, b . These provide a central rim  456 . The grooves  461 ,  465  all include a single resilient member or lug  463 . Lug  463  is described hereinbefore with reference to  FIGS. 4-13 . Lugs  463  are arranged on opposing side walls  371   b ,  371   a  of the rim  456  located between the grooves  461   a ,  465   a . Lugs  463  are also arranged on matching side walls of the outer grooves  461   b ,  465   b . As such the lugs  463  provide multiple uni-directional sealing points along the apparatus  410 . As the lugs  463  are unidirectional, if there is a pressure build up between lugs facing the same way the upper lugs flex outwards (burp) to let pressurised fluid out. 
     Like the embodiment of  FIG. 15 , groove  461   b  includes a port  490  being an aperture between the base  477  of the groove  461   b  and the outer surface  492  of the second tubular member  432 . Groove  465   b  includes a slot  494  along the inner surface  438  connecting the groove  465   b  with the bore above the upper end  426  of the first tubular member  412 . Slot  494  provides a bypass channel to allow fluid to exit at the top of the first tubular member  412 . An additional feature of this embodiment is the introduction of a slot  96  in the rim  456   a, b  to provide a fluid bypass channel between similarly profiled grooves  465 ,  461 . Unidirectional sealing lugs  463  with bypass slots  96  ensure that the lugs  463  do not inadvertently seal in the opposite direction, leading to hydraulic lock during morphing. 
     An alternative arrangement to the slots  96  on rims  456  is to provide a helical groove  98  cut into the inner surface  438  of the second tubular member  432  at the connector apparatus  410 . This is illustrated in  FIG. 17 . This provides a fluid exit path between the grooves  461 ,  465 . 
     The principle advantage of the present invention is that it provides a connection apparatus for joining two tubular members with an improved metal to metal seal between the members. 
     A further advantage of the present invention is that it provides a connection apparatus for joining two tubular members in which following morphing, a metal to metal seal is retained even when the tubular members relax. 
     A yet further advantage of at least one embodiment of the present invention is that it provides a connection apparatus for joining two tubular members by morphing into grooves arranged on a member which does not require the use of fluid exclusion means such as syntactic foam. 
     It will be appreciated by those skilled in the art that modifications may be made to the invention herein described without departing from the scope thereof. For example, when the tubular members have been described as metal structures, only the end portions need to have metal to form the seal and thus the tubular members may be of composite form with metal ends. While integrally formed lug projections may be formed in the milled recesses of the inner surface of the outer tubular, or may be stand alone components inserted into recesses in the outer tubular, it will be appreciated that a combination of these two different lug constructions may be used within a single connector apparatus. In addition, fluid exclusion means may be inserted into recesses with integral milled lug details or inserted into recesses along with lug components. Stud projections may or may not be provided on the upper surface of the projecting lugs of the connector apparatus and although in the illustrated embodiments an arrangement with a single stud projection is shown, the stud projections may be formed as a plurality of discreet point projections which form a circular seal, or may be formed as a curvilinear projection which forms a circular seal. In addition, either one ring of stud projection may be provided or a plurality of circumferential stud projection circles may be arranged on the uppers surface of the lugs to further enhance the seal effect provided.