FIELD OF THE INVENTION

The present invention relates to an expansion apparatus, and in particular to an expansion apparatus for use in expanding respective portions of two or more tubular members.

BACKGROUND TO THE INVENTION

Many industries require pipes to be connected end to end to define a continuous and normally fluid tight conduit. For example, in the oil and gas industry lengths of pipe called casing are secured together to form a casing string which is run into a drilled bore and cemented in place to provide wellbore support and define a reliable fluid conduit for wellbore and other fluids. Such pipes are conventionally secured together by threaded connectors, which have associated disadvantages. For example, threaded connectors require the pipe ends to be accurately machined to create the male and female threads, which increases the production costs. Additionally, individual pipes require precise handling during make-up of the threaded connection to ensure proper thread alignment. Additionally, many sealing problems may be encountered with threaded connectors, and to minimise the possibility of leakage at a threaded connector the individual threads are typically manufactured to very high tolerances, again increasing production costs. Also, separate seals and/or thread compounds are typically utilised to assist to improve connector sealing integrity. However, the use of such seals and compounds increases costs and installation time.

It has been proposed in the art to secure lengths of pipe together by welding, for example by forge welding. However, while welding pipes together may address many issues relating to threaded connectors, many other concerns arise. For example, it is understood that weld integrity can be significantly compromised when individual pipes are not accurately aligned during the welding process. However, it is often the case that pipes are manufactured to wide band tolerances on many ruling dimensions such that considerable variations exist between different pipes to be connected together, presenting alignment issues. These tolerances applied to pipe inner and outer diameters, together with wall thickness variations, ovality and concentricity make it difficult to weld pipe sections coaxially and concentrically together.

Also, most pipe welding applications require the pipes to be gripped while applying relatively large axial loads. However, such loads can result in the pipe material being stressed beyond yield, causing local plastic damage, and contributing to loss of axial motion when large axial forces are applied.

SUMMARY OF THE INVENTION

According to a first aspect of the present invention there is provided an expansion apparatus comprising:

a first expansion assembly configured to engage a first tubular member; and a second expansion assembly coaxially aligned with the first expansion assembly and configured to engage a second tubular member.

The first expansion assembly may be configured to engage an end region of a first tubular member. The second expansion assembly may be configured to engage an end region of a second tubular member.

In use, the expansion apparatus may be configured for use to expand respective regions, such as end regions, of first and second tubular members. Coaxially aligning the first and second expansion assemblies assists to ensure that the respective regions of first and second tubular members are expanded relative to a common datum. This may permit the respective regions, such as end regions of the first and second tubular members to be expanded to define substantially identical geometric and/or dimensional properties. The expansion apparatus of the present invention may be configured for use in preparing respective regions of first and second tubular members prior to a joining process, for example a welding process, such as a forge welding process. In this respect, utilising the expansion apparatus to expand respective regions of the tubular bodies assists to ensure that the tubulars can be accurately aligned prior to welding, which may permit improved weld quality to be achieved. This may obviate or at least mitigate problems associated with welding together tubular bodies, such as problems relating to different dimensional tolerances and the like.

The first and second expansion assemblies may be configured to expand respective first and second tubular members simultaneously. The first and second expansion assemblies may be configured to expand first and second tubular members sequentially.

The first and second expansion assemblies may be adapted to be located internally of first and second tubular members, and be configured to radially expand said tubulars.

The first and second expansion assemblies may be defined by a single expansion structure. The single expansion structure may be controlled to operate both the first and second expansion assemblies. Alternatively, the first and second expansion assemblies may be provided by independent expansion structures. This may permit independent control of the first and second expansion assemblies.

The first and second expansion assemblies may be located in close proximity relative to each other. In this arrangement, respective ends of first and second tubular members may be arranged adjacent to each other to be expanded. This may assist in reducing process time, for example welding process time as the tubular bodies may be appropriately aligned and positioned following expansion to be welded by a suitable method.

The first and second expansion assemblies may be mounted on a support body, such as a mandrel. In this arrangement the expansion assemblies may be axially arranged along the support body. The apparatus may comprise a single support body configured to support both the first and second expansion assemblies. Alternatively, the apparatus may comprise first and second support bodies configured to support a respective expansion assembly.

The first and second expansion assemblies may be substantially identically configured. Alternatively, the first and second expansion assemblies may be configured differently.

One or both of the expansion assemblies may comprise at least one expansion element adapted to be displaced radially outwardly to engage one or more tubular members. One or both of the expansion assemblies may comprise a plurality of circumferentially arranged expansion elements adapted to be displaced radially outwardly to engage one or more tubular members. The expansion elements may be arranged to be entirely displaced radially outwardly. Alternatively, the expansion elements may be arranged to pivot about a fixed point, such that pivoting motion of the expansion elements effects radial displacement thereof.

One or both of the expansion assemblies may comprise at least one drive arrangement configured to radially displace the at least one expansion element. The drive arrangement may comprise a hydraulic drive arrangement, pneumatic drive arrangement, mechanical drive arrangement or the like, or any suitable combination thereof. A single drive arrangement may be associated with a single expansion element. Alternatively, a single drive arrangement may be associated with a plurality of expansion elements

The drive arrangement may comprise a cam assembly. In one embodiment the drive arrangement may comprise a cam member comprising a cam surface configured to engage at least one expansion element, wherein relative movement of the cam member and the at least one expansion element in a first direction may radially extend the expansion element. Relative movement of the cam surface and the at least one expansion element in a second direction, which may be opposite to the first direction, may permit retraction of the expansion element.

The cam surface may taper in an axial direction, such that relative axial movement of the cam surface and the expansion element effects radial displacement of said expansion element.

The drive arrangement may comprise an actuator configured to displace the cam member. The actuator may be integrally formed with the cam member. Alternatively, the actuator may be formed separately of the cam member. In one embodiment the actuator may comprise a piston, such as an annular piston.

The cam surface may be configured to directly engage the at least one expansion element. Alternatively, the cam surface may be configured to indirectly engage the expansion element. For example, a component, material or the like may be interposed between the cam surface and the at least one expansion element.

The drive arrangement may comprise a plurality of individual cam surfaces configured to engage one or more expansion elements. The drive arrangement may comprise a substantially conical structure, wherein the at least one cam surface is defined on the conical structure. The conical structure may define a plurality of lands each defining a respective cam surface.

The cam member may be adapted to be coupled to one or more expansion elements. The cam member may be coupled to one or more expansion elements via an interengaging profile, such as a dovetail profile. The interengaging profile may be integrally formed on the cam member and one or more expansion elements.

Alternatively, the interengaging profile may be at least partially defined by separate components configured to be secured to one or both of the cam member and the expansion element.

The apparatus may comprise a first drive arrangement associated with the first expansion assembly, and a second drive arrangement associated with the second expansion assembly, wherein the first and second drive arrangements are configured to operate in mutually opposite directions to extend the associated expansion assembly. This arrangement may assist to eliminate any net reaction forces acting on the expansion apparatus by operation of the drive arrangements, preventing or at least minimising any undesired movement of the apparatus.

The first and second expansion assemblies may be electrically insulated from each other. This arrangement may be advantageous in applications in which the expansion apparatus is used during a welding process which relies on electrical heating.

The expansion apparatus may comprise a gripping assembly configured to grip a tubular member to be expanded. This arrangement may therefore permit a tubular member to be robustly secured prior to and/or during and/or after expansion. The gripping assembly may be configured to provide support to a tubular member subject to gripping from an external source. The gripping assembly may assist to prevent deformation, such as crushing, of a tubular member during gripping by an external source.

The expansion apparatus may comprise a single gripping assembly configured to grip first and second tubular members to be expanded. In one embodiment the expansion apparatus may comprise a first gripping assembly configured to grip a first tubular member to be expanded by the first expansion assembly, and a second gripping assembly configured to grip a second tubular member to be expanded by the second expansion assembly. The first and second gripping assemblies may be substantially identically configured. Alternatively, the first and second gripping assemblies may be configured differently.

One or both of the first and second gripping assemblies may comprise at least one and preferably a plurality of gripping elements. The gripping elements may be circumferentially distributed. The gripping elements may be configured to be radially extended and retracted to achieve respective gripping and releasing of a tubular member. The gripping assembly may comprise a drive arrangement configured to displace at least one gripping element to effect gripping. The drive arrangement may comprise a cam member comprising a cam surface configured to engage at least one gripping element, wherein relative movement of the cam member and the at least one gripping element in a first direction may radially extend the expansion element. Relative movement of the cam surface and the at least one gripping element in a second direction, which may be opposite to the first direction, may permit retraction of the gripping element.

The cam surface may taper in an axial direction, such that relative axial movement of the cam surface and the gripping element effects radial displacement of said gripping element.

The gripping drive arrangement may comprise an actuator configured to displace the cam member. The actuator may be integrally formed with the cam member. Alternatively, the actuator may be formed separately of the cam member. In one embodiment the actuator may comprise a piston, such as an annular piston.

The cam surface may be configured to directly engage the at least one gripping element. Alternatively, the cam surface may be configured to indirectly engage the expansion element. For example, a component, material or the like may be interposed between the cam surface and the at least one expansion element.

The gripping drive arrangement may comprise a plurality of individual cam surfaces configured to engage one or more gripping elements.

The cam member may be adapted to be coupled to one or more expansion elements. The cam member may be coupled to one or more expansion elements via an interengaging profile, such as a dovetail profile.

The apparatus may comprise a first gripping drive arrangement associated with the first gripping assembly, and a second gripping drive arrangement associated with the second drive assembly, wherein the first and second drive arrangements are configured to operate in mutually opposite directions to extend the associated gripping assembly. This arrangement may assist to eliminate any net reaction forces acting on the expansion apparatus by operation of the gripping drive arrangements, preventing or at least minimising any undesired movement of the apparatus.

The expansion apparatus may comprise a sealing arrangement configured to establish a seal between the apparatus and a tubular being expanded. The sealing arrangement may be configured to be established to provide isolation within a region of tubular expansion. This arrangement may be provided to permit desired atmospheric conditions to be achieved in the region of expansion. For example, it may be desirable to establish a particular atmospheric composition by delivering a gas, such as an inert gas, to the region of expansion, establish a vacuum in the region of expansion, or the like. This may be desirable in welding applications, wherein the region of expansion may be subjected to a welding operation, such as a forge welding operation.

The sealing arrangement may be configured to establish a seal in an annular region defined between the expansion apparatus and tubular member.

The sealing arrangement may be selectively operated. In this way the seal arrangement may be energised when required, and de-energised when no longer required. The sealing arrangement may comprise a mechanically actuated seal. The sealing arrangement may comprise an inflatable seal.

In one embodiment the sealing arrangement may comprise a first sealing assembly configured to establish a seal between the expansion apparatus and a first tubular member, and a second sealing assembly configured to establish a seal between the expansion apparatus and a second tubular member.

The expansion assembly may be configured to function as an electrode, such as an electrode configured for use in electrically heating a tubular.

The expansion apparatus may be configured to expand first and second wellbore tubular members, such as casing tubular members.

According to a second aspect of the present invention there is provided a method of expanding first and second tubular members, comprising: arranging an expansion apparatus within the first and second tubular members, wherein the expansion apparatus comprises coaxially aligned first and second expansion assemblies; and

activating the first and second expansion assemblies to respectively engage the first and second tubular bodies.

The method may comprise activating the first and second expansion assemblies simultaneously. Alternatively, the expansion assemblies may be activated sequentially.

The expansion apparatus according to the first aspect may be utilised within the method according to the second aspect. Accordingly, features described above in relation to the first aspect may be assumed to apply to the second aspect.

According to a third aspect of the present invention there is provided a welding apparatus comprising the expansion apparatus according to the first aspect.

According to a fourth aspect of the present invention there is provided a method of welding a first tubular member to a second tubular member, comprising: arranging an expansion apparatus within the first and second tubular members, wherein the expansion apparatus comprises coaxially aligned first and second expansion assembles;

activating the first and second expansion assemblies to respectively engage the first and second tubular bodies; and

welding the first and second tubular members together.

The method may comprise activating the first and second expansion assemblies to engage respective end regions of the first and second tubular members, and welding said respective end regions together.

The welding apparatus and method according to the third and fourth aspects respectively may incorporate features defined above in relation to the first and second aspects. According to a fifth aspect of the present invention there is provided an expansion apparatus configured to prepare respective end regions of first and second tubular members prior to being welded together, said apparatus comprising first and second expansion assemblies configured to engage respective end regions of first and second tubular members to define substantially equal inner diameters in said respective end regions.

According to a sixth aspect of the present invention there is provided a method of welding first and second tubular members together, comprising:

engaging respective end regions of the first and second tubular members with an expansion apparatus to define substantially equal inner diameters in the said respective end regions; and

welding together the respective end regions.

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:

Figure 1 is a diagrammatic representation of end regions of first and second tubular members to be welded together;

Figure 2 shows an expansion apparatus in accordance with an embodiment of the present invention, shown in use with first and second tubular members;

Figure 3 is a longitudinal cross section of the expansion apparatus of Figure

1 ;

Figure 4 shows the expansion apparatus removed from the tubular members; Figure 5 is an enlarged view in the region of a first expansion assembly of the expansion apparatus, with some components removed for clarity: and

Figure 6 is an enlarged view in the region of a first gripping assembly of the expansion apparatus, with some components removed for clarity. DETAILED DESCRIPTION OF THE DRAWINGS

Reference is first made to Figure 1 in which there is shown respective end regions 10, 12 of a first tubular member 14 and a second tubular member 16. In this case the tubular members 14, 16 represent wellbore casing. As demonstrated in Figure 1 , it is possible for individual casing tubulars which, although manufactured to the same general ruling dimensions, exhibit dimensional variations, such as variations in inner diameter, outer diameter and wall thickness. These variations may occur due to relatively wide band permitted tolerances.

In the oil and gas industry long casing strings are formed by securing together individual casing tubulars using threaded connections. Any dimensional variations in the individual tubulars does not usually generate any particular problems, as the individual threads for the connection are machined to very accurate tolerances. However, recent developments in the oil and gas industry relate to the concept of joining individual tubulars together by welding, for example by forge welding. Welding requires the ends of the individual tubulars to be very accurately aligned in order to minimise problems during the welding process, and to minimise any potential weld defects. As such, the wide band tolerances on pipe dimensions represents a particular problem.

Reference is now made to Figure 2 in which there is shown an expansion apparatus, generally identified by reference numeral 20, in accordance with an embodiment of the present invention. The apparatus 20 is shown located within first and second casing tubulars 14, 16 which are arranged with respective end portions 10, 12 generally aligned and positioned adjacent each other in preparation for welding together. As will be described in further detail below, the expansion apparatus 20 is configured to expand the end regions 10, 12 of the respective tubulars 14, 16 to define a common inner diameter relative to a common central axis, in order to assist alignment for welding. Although not illustrated, the lower casing 1 tubular 16 extends downwardly towards a wetlbore and is secured relative to a work platform, such as a rig floor.

The apparatus 20 is supported via a tubing string 22, such as a coiled tubing string, which is configured to provide support and deliver hydraulic pressure.

The apparatus 20 comprises a first, upper expansion assembly 24 and a second, lower expansion assembly 26, wherein the expansion assemblies 24, 26 are coaxially arranged and are configured to expand the respective end regions 10, 12 of the tubulars 14, 16. For the purposes of the present description, the upper expansion assembly 24 is shown in the expanded configuration, with the end region 10 of tubular 14 slightly expanded radially outwardly, and the lower expansion assembly 26 is shown in a retracted configuration.

As will be described in further detail below, each expansion assembly 24, 26 comprises a plurality of expansion elements in the form of fingers 24a, 26a which are displaced radially outwardly by a desired amount to effect expansion of the tubulars 14, 16.

The apparatus 20 further comprises a first, upper gripping assembly 30 configured to grip the upper tubular 14, and a second, lower gripping assembly 32 configured to grip the lower tubular 16. Each gripping assembly 30, 32 may be configured to grip a respective tubular 14, 16, for example to secure the tubulars to the apparatus 10. Additionally, or alternatively, each gripping assembly 30, 32 may be configured to provide internal support to the respective tubulars to prevent deformation by any external gripping force, as represented by arrows 34, 36. External gripping may be provided from a welding apparatus (not shown). Each gripping assembly 30, 32 comprises a plurality of circumferentially arranged gripping elements 30a, 32a which are configured to be displaced outwardly to effect gripping.

For the purposes of the present description, the upper gripping elements 30a are shown in an extended, gripping configuration, and the lower gripping elements 32a are shown in a retracted configuration. The apparatus 20 further comprises a first, upper sealing arrangement 40, and a second, lower sealing arrangement 42 configured to provide an annular seal between the apparatus 10 and the internal surface of the respective tubular 14, 16. Accordingly, the sealing arrangements 40, 42 may permit the internal region in the vicinity of the end portions 10, 12 of the respective tubulars 14, 16 to be isolated.

This may permit sealing to be achieved to contain a gas, such as an inert gas used during a welding process. Each sealing arrangement 40, 42 comprises a pair of annular inflatable sealing elements 40a, 42a.

Reference is now made to Figure 3 in which a longitudinal cross-sectional view of the apparatus 20 is shown, in addition to Figure 4 in which the apparatus 20 is shown removed from the tubulars 14, 16.

The apparatus 20 comprises a central mandrel 50 which supports the expansion assemblies 24, 26, the gripping assemblies 30, 32 and the sealing arrangements 40, 42. This common mandrel 50 permits both expansion assemblies 24, 26 to be centred about a common axis, assisting to ensure that the tubular members 14, 16 are expanded relative to a common datum. The mandrel 50 is electrically insulated from each of the supported components to prevent electrical communication therebetween, for example of electrical current used to heat the tubulars 14, 16 for welding.

It should be noted that in the embodiment disclosed the expansion assemblies 24, 26 are substantially identical, as are the gripping assemblies 30, 32 and the sealing arrangements 40, 42. Accordingly, for brevity only the upper expansion assembly 24, upper gripping assembly 30 and upper sealing arrangement 40 will be described.

The upper expansion assembly 24 comprises the plurality of circumferentially arranged expansion fingers 24a which are displaceable radially outwardly by a drive arrangement mounted on the mandrel 50 and which includes a cone member 52 having a cam face 54, and a double acting annular piston 56. Actuation of the piston 56 causes axial displacement of the cone member 52 which results in radial movement of the fingers 24a by engagement with the cam face 54.

Reference is now additionally made to Figure 5 in which there is shown an enlarged perspective view in the region of the expansion assemblies 24, 26, with some expansion fingers 24a, 26a removed for clarity. The cone member 52 comprises a plurality of individual lands or cam surfaces 54a, each configured to engage a respective expansion finger 24a. Each cam surface 54a comprises or defines an axially extending dovetail slot 54b which slidably receives a respective dovetail spar 54c, wherein each expansion finger 24a is secured to a respective spar 54c via screws 58. Accordingly, the expansion fingers 24a are inter-engaged with the cone member 52 such that separation is not possible. Furthermore, each expansion finger 24a is secured against axial movement by pins 60 which are slidably received within radially extending bores 62 in the fingers 24a.

Each expansion finger 24a includes an expansion insert 24b, which may be of a hardened material and be replaceable, wherein each insert 24b defines an outwardly tapering surface. This configuration may assist in achieving a required deformation of the tubular member.

Referring again to Figure 3, the upper gripping assembly 30 also comprises a drive arrangement mounted on the mandrel 50 for displacing the gripping elements 30a radially outwardly, wherein the drive arrangement includes a cone member 64 having a pair of axially separated cam faces 66, 68, and a double acting annular piston 70. Actuation of the piston 70 causes axial displacement of the cone member 64 which results in radial movement of the gripping elements 30a by engagement with the cam faces 66, 68.

Reference is now additionally made to Figure 6 in which there is shown an enlarged perspective view in the region of the upper gripping assembly 30, with some gripping elements 30a removed for clarity. Providing cam surface 66, 68 which are axially separated permits the gripping elements 30a to be increased in length while still being supported by the cone members 64, without increasing the radial dimensions of the apparatus 20. Each cam surface 66, 68 of the cone member 64 comprises a plurality of individual lands or cam surfaces 66a, 68a, each configured to engage respective cam surfaces 30b, 30c on each gripping element 30a.

The configuration of the upper sealing arrangement 40 will now be briefly described with reference again to Figure 3. The sealing arrangement 40 comprises a support sleeve 72 mounted on the mandrel 50, wherein the support sleeve supports the pair of annular inflatable sealing elements 40a. Upon inflation of the sealing elements 40a, for example by hydraulic fluid, the elements will extend radially outwardly to engage the inner wall surface of the tubular.

As noted previously, the expansion apparatus 20 may be used to prepare tubular members 14, 16 for welding. In one exemplary use, which is described with reference again to Figure 2, the lower tubular member 16 is held relative to a rig floor, for example by conventional pipe slips, or alternatively/additionally by a welding apparatus. The apparatus 20 is located within the upper tubular 14, with the upper expansion assembly 24 aligned with a lower end portion 10 of the upper tubular 14, and the upper gripping assembly 30 activated to grip and support the tubular 14. The upper tubular 14 and apparatus 20 are then manipulated such that the lower end of the apparatus 20 is inserted within the lower tubular 16, and the tubulars 14, 16 are positioned as shown in Figure 2. Following this the respective end portions 10, 12 of the tubulars 14, 16 are expanded by the expansion assemblies 24, 26 to assist with alignment prior to welding. The upper and lower sealing arrangements 40, 42 may be activated and a required environment, such as a vacuum, may be established in the region of welding. A welding apparatus may then heat the end portions 10, 12 of the tubulars 14, 16, which may then be brought together with a required force to effect forge welding.

It should be noted that the expansion assemblies 24, 26 are configured to engage the tubular members 14, 16 in order to eliminate any problems associated with dimensional variations, for example due to wide band manufacturing tolerances. In some cases a tubular member may be provided which already exhibits the necessary dimensions, such that expansion is not required. In this case the appropriate expansion assembly may still be utilised as confirmation of this.

It should be understood that the embodiment described herein is merely exemplary and that various modifications may be made thereto without departing from the scope of the invention. For example, the expansion fingers may each comprise an integrally formed spar configured to be received within the dovetail slot in the cam member of the drive arrangement. In the embodiment shown the respective drive arrangements for the expansion and gripping assemblies comprise pistons. In alternative embodiments a mechanical drive arrangement may be utilised, such as a motor or the like. Additionally, the gripping elements of the gripping assemblies may be secured to an expansion cone view an inter-engaging profile, such as a dovetail profile.