CA2557965C - Procedures and equipment for profiling and jointing of pipes - Google Patents

Abstract

Methods and apparatus for shaping pipes, tubes, liners, or casing at downhole locations in wells. Use is made of rollers bearing radially outwards against the inside wall of the pipe (etc.), the rollers being rolled around the pipe to cause outward plastic deformation which expands and shapes the pipe to a desired profile. Where one pipe is inside another, the two pipes can be joined without separate components (except optional seals). Landing nipples and liner hangers can be formed in situ. Valves can be deployed to a selected downhole location and there sealed to the casing or liner without separate packers. Casing can be deployed downhole in reduced-diameter lengths and then expanded to case a well without requiring larger diameter bores and casing further uphole. The invention enables simplified downhole working, and enables a well to be drilled and produced with the minimum downhole bore throughout its depth, obviating the need for large bores. When expanding lengths of casing, the casing does not need to be anchored or made pressure-tight. The profiling/expansion tools of the invention can be deployed downhole on coiled tubing, and operated without high tensile loads on the coiled tubing.

Description

2 AND JOINTING OF PIPES

3

4 This is a divisional application of Canadian Patent Application Serial No. 2,356,194 filed on December 21, 1999.

7 This invention relates to procedures and equipment for 8 profiling and jointing of pipes, and relates more 9 particularly but not exclusively to methods and apparatus for the shaping and/or expansion and/or conjoining of 11 tubular casings in wells. The expression "the invention"
12 and the like encompasses the subject matter of both the 13 parent and the divisional application.

In the hydrocarbon exploration and production industry there 16 is a requirement to deploy tubular casings in relatively 17 narrow-bore wells, and to expand the deployed casing in 18 situ. The casing may require to be expanded throughout its 19 length in order to line a bore drilled through geological material; the casing may additionally or alternatively 21 requir.e to be expanded at one end where it overlaps and lies 22 concentrically within another length of previously deployed 23 casing in order to form a swaged joint between the two 24 lengths of casing. Proposals have been made that a slotted metal tube be expanded by mechanically pulling a mandrel 26 through the tube, and that a solid-walled steel tube be 27 expanded by hydraulically pushing a part-conical ceramic 28 plunger through the tube. In both of these proposals, very 29 high longitudinal forces would be exerted throughout the length of the tubing, which according would require to be 31 anchored at one end.

WO 00/37766 PCT/GB99/04225.

1 Where mechanical pulling is to be employed, the pulling 2 force would require to be exerted through a drillstring 3 (in relatively large diameter wells) or through coiled 4 tubing (in relatively small diameter wells). The necessary force would become harder to apply as the 6 well became more deviated (i.e. more non-vertical), and 7 in any event, coiled tubing may not tolerate high 8 longitudinal forces. Where hydraulic pushing is to be 9 employed, the required pressure may be hazardously high, and in any event the downhole system would 11 require to be pressure-tight and substantially leak-12 free. (This would preclude the use of a hydraulically 13 pushed mandrel for the expansion of slotted tubes).
14 The use of a fixed-diameter mandrel or plug would make it impracticable or impossible to control or to vary 16 post-deformation diameter after the start of the 17 expansion procedure.

18 It is therefore an object of the invention to provide 19 new and improved procedures and equipment for the profiling or jointing of pipes or other hollow tubular 21 articles, which obviate or mitigate at least some of 22 the disadvantages of the prior art.

23 In the following specification and claims, references 24 to a"pipe" are to be taken as references to a hollow tubular pipe and to other forms of hollow tubular 26 article, and references to "profiling" are to be taken 27 as comprising alteration of shape and/or dimension(s) 28 which alteration preferably takes place substantially 29 without removal of material. -31 According to a first aspect of the present invention 32 ttiere is provided a profiling method for profiling a 33 pipe or other hollow tubular article, the profiling 1 method comprising the steps of applying a roller means 2 to a part of the pipe bore selected to be profiled, 3 translating the roller means across the bore in a 4 direction including a circumferential component while applying a force to the roller means in a radially 6 outwards direction with respect to the longitudinal 7 axis of the pipe, and continuing such translation and 8 force application until the pipe is plastically 9 deformed substantially into the intended profile.
The deformation of the pipe may be accomplished by 11 radial compression of the pipe wall or by 12 circumferential stretching of the pipe wall, or by a 13 combination of such radial compression and 14 circumferential stretching.

Said direction may be purely circumferential, or said 16 direction may partly circumferential and partly 17 longitudinal.

18 Said roller means is preferably peripherally profiled 19 to be complementary to the profile into which the selected part of the pipe bore is intended to be 21 formed.

22 The selected part of the pipe bore may be remote from 23 an open end of the pipe, and the profiling method then 24 comprises the further steps of inserting the roller means into the open end of the pipe (if the roller 26 means is not already in the pipe), and transferring the 27 roller means along the pipe to the selected location.
28 Transfer of the roller means is preferably accomplished 29 by the step of actuating traction means coupled to or forming part of the roller means and effective to apply 31 along-pipe traction forces to the roller means by 1 reaction against parts of the pipe bore adjacent the 2 roller means.

3 The profiling method according to the first aspect of 4 the present invention can be applied to the profiling of casings and liners deployed in a well (e.g. a 6 hydrocarbon exploration or production well) , and the 7 profile created by use of the method may be a liner 8 hanger, or a landing nipple, or another such downhole 9 profile of the type which previously had to be provided by inserting an annular article or mechanism into the 11 well, lowering it the required depth, and there 12 anchoring it (which required either a larger diameter 13 of well for a given through diameter, or a restricted 14 through diameter for a given well diameter, together with the costs and inconvenience of manufacturing and 16 installing the article or mechanism). Additionally or 17 alternatively, the profiling method according to the 18 first aspect of the present invention can be applied to 19 increasing the diameter of a complete length of pipe;
for example, where a well has been cased to a certain 21 depth (the casing having a substantially constant 22 diameter), the casing can be extended downwardly by 23 lowering a further length of pipe (of lesser diameter 24 such th~Lt it freely passes,down the previously installed casing) to a depth where the top of the 26 further length lies a short way into the lower end of 27 the previously installed casing and there expanding the 28 upper end of the further length to form a joint with 29 the lower end of the previously installed casing (e.g.
by using the method according to the second aspect of 31 the present invention), followed by circumferential 32 expansion of the remainder of the further length to 33 match the bore of the previously installed casing.

1 According to a second aspect of the present invention 2 there is provided a conjoining method for conjoining 3 two pipes or other hollow tubular articles, said 4 conjoining method comprising the steps of locating one

5 of the two pipes within and longitudinally overlapping

6 one of the other of the two pipes, applying roller

7 means to a part of the bore of the inner of the two

8 pipes at a location where it is intended that the two

9 pipes be conjoined, translating the roller means across the bore in a direction including a circumferential 11 component while applying a radially outwardly directed 12 force to the roller means, and continuing such 13 translation and force application until the inner pipe 14 is plastically deformed into permanent contact with the outer pipe and is thereby conjoined thereto.

16 Said deformation may be accomplished by radial 17 compression of the pipe wall or by circumferential 18 stretching of the pipe wall, or by a combination of 19 such radial compression and circumferential stretching.
Said direction may be purely circumferential, or said 21 direction may be partly circumferential and partly 22 longitudinal.

23 The location where the pipes are intended to be 24 conjoined may be remote from an accessible end of the bore, and the conjoining method then comprises the 26 further steps of inserting the roller means into the 27 accessible end of the bore (if the roller means is not 28 already in the bore), and transferring the roller means 29 to the intended location. Transfer of the roller means is preferably accomplished by the step of actuating 31 traction means coupled to or forming part of the roller 32 means and effective to apply along-bore traction forces 1 to the roller means by reaction against parts of the 2 pipe bore adjacent the roller means.

3 The conjoining method according to the second aspect of 4 the present invention can be applied to the mutual joining of successive lengths of casing or liner 6 deployed in a well (e.g. a hydrocarbon exploration or 7 production well), such that conventional screw-threaded 8 connectors are not required.

9 According to third aspect of the present invention, there is provided expansion apparatus for expanding a 11 pipe or other hollow tubular article, said expansion 12 apparatus comprising roller means constructed or 13 adapted for rolling deployment against the bore of the 14 pipe, said roller means comprising at least one set of individual rollers each mounted for rotation about a 16 respective rotation axis which is generally parallel to 17 the longitudinal axis of the apparatus, the rotation 18 axes of said at least one set of rollers being 19 circumferentially distributed around the expansion apparatus and each being radially offset from the 21 longitudinal axis of the expansion apparatus, the 22 expansion apparatus being selectively rotatable around 23 its longitudinal axis. = ' 24 The rotation axes of said at least one set of rollers may conform to a first regime in which each said 26 rotation axis is substantially parallel to the 27 longitudinal axis of the expansion apparatus in a 28 generally cylindrical configuration, or the rotation 29 axes of said at least one set of rollers may conform to a second regime in which each said rotation axis lies 31 su'bstantially in a respective radial plane including 32 the longitudinal axis of the expansion apparatus and 1 the rotation axes each converge substantially towards a 2 common point substantially on the longitudinal axis of 3 the expansion apparatus in a generally conical 4 configuration, or the rotation axes of said at least one set of rollers may conform to third regime in which 6 each said rotation axis is similarly skewed with 7 respect to the longitudinal axis of the expansion 8 apparatus in a generally helical configuration which 9 may be non-convergent (cylindrical) or convergent (conical). Rollers in said first regime are 11 particularly suited to profiling and finish expansion 12 of pipes and other hollow tubular articles, rollers in 13 said second regime are particularly suited to 14 commencing expansion in, and to flaring of pipes, and other hollow tubular articles, while rollers in said 16 third regime are suited to providing longitudinal 17 traction in addition to such functions of the first or 18 second regimes as are provided by other facets of the 19 roller axes besides skew. The expansion apparatus may have only a single such set of rollers, or the 21 expansion apparatus may have a plurality of such sets 22 of rollers which may conform to two or more of the 23 aforesaid regimes of roller axis alignments; in a 24 particular example where the expansion apparatus has a set of rollers conforming to the second regime located 26 at leading end of the exemplary expansion apparatus and 27 another set of rollers conforming to the first regime 28 located elsewhere on the exemplary expansion apparatus, 29 this exemplary expansion apparatus is particularly suited to expanding complete lengths of hollow tubular 31 casing by reason of the conically disposed leading set 32 of rollers opening up previously unexpanded casing and 33 the following set of cylindrically disposed rollers 34 finish-expanding the casing to its intended final diameter; if this exemplary expansion apparatus were 1 modified by the addition of a further set of rollers 2 conforming to third regime with non-convergent axes, 3 this further set of rollers could be utilised for the 4 purpose of applying traction forces to the apparatus by means of the principles described in the present 6 inventor's previously published PCT patent application 7 W093/24728-Al. This document discloses a downhole tool for 8 providing radial support for a rotatable downhole assembly.
The tool comprises a plurality of rolling element means which are each rotatably mounted on an axis which is tangential to a notional helix which lies substantially co-12 axial with the longitudinal axis of the tool. Rotation of 13 the tool will cause rotation of the rolling element means 14 about their skewed axes and this acts to translate rotation of the tool into a longitudinally-directed force acting 16 upon the tool, providing a traction force in the direction 17 of the longitudinal axis of the tool. Rotation of the rolling element means that their skewed axes generates a traction force which may me applied to apparatus.

22 The rollers of said expansion apparatus may each be 23 mounted for rotation about its respective rotation axis 24 substantially without freedom of movement along its respective rotation axis, or the rollers may each be 26 mounted for rotation about its respective rotation axis 27 with freedom of movement along its respective rotation 28 axis, preferably within predetermined limits of 29 movement. In the latter case (freedom of along-axis movement within predetermined limits), this is advantageous in the particular case of rollers 31 conforming to the afore-mentioned second regime (i.e_ a 32 conical array of rollers) in that the effective maximum 33 outside diameter of the rollers depends on the position of the.rollers along the axis of the expansion 8a 1 apparatus and this diameter is thereby effectively 2 variable; this allows relief of radially.outwardly. 3 directed forces by longitudinally retracting the 4 expansion apparatus to allow the rollers collectively to move longitudinally in the convergent direction and 6 hence collectively to retract radially inwards away from the bore against which they were immediately previously pressing.

9 According to a fourth aspect of the present invention, there is provided profiling/conjoining apparatus for 11 profiling or conjoining pipes or other hollow tubular 1 articles, said profiling/conjoining apparatus 2 comprising roller means and radial urging means 3 selectively operable to urge the roller means radially 4 outwards of a longitudinal axis of the profiling/conjoining apparatus, the radial urging means 6 causing or allowing the roller means to move radially 7 inwards towards the longitudinal axis of the 8 profiling/conjoining apparatus when the radial urging 9 means is not operated, the roller means comprising a plurality of individual rollers each mounted for 11 rotation about a respective rotation axis which is 12 substantially parallel to the longitudinal axis of the 13 profiling/conjoining apparatus, the rotation axes of 14 the individual rollers being circumferentially distributed around the apparatus and each said rotation 16 axis being radially offset from the longi.tudinal axis 17 of the profiling/conjoining apparatus, the 18 profiling/conjoining apparatus being selectively 19 rotatable around its longitudinal axis to translate the roller means across the bore of a pipe against which 21 the roller means is being radially urged.

23 The radial urging means may comprise a respective 24 piston on which each said roller is individually rotatably mounted, each said piston being slidably 26 sealed in a respective radially extending bore formed 27 in a body of the profiling/conjoining apparatus, a 28 radially inner end of each said bore being in fluid 29 communication with fluid pressure supply means selectively pressurisable to operate said radial urging 31 means.

32 Alternatively, the radial urging means may comprise bi-33 cohical race means upon which each said individual 34 roller rolls in use of the profiling/conjoining apparatus, and separation variation means selectively operable controllably to vary the longitudinal separation of the two conical races of the bi-conical race means whereby correspondingly to vary the radial displacement of each said roller rotation axis from the longitudinal axis of the profiling/conjoining apparatus. The separation variation means may comprise hydraulic linear motor means selectively pressurisable to drive one of said two cones longitudinally towards and/or away from the other said cone.

According to an aspect of the present invention there is provided an apparatus for expanding a tubular in a wellbore, comprising a tubular run-in string to transport the apparatus into the wellbore and to provide fluid thereto, and an expander tool, disposable in the tubular, the expander tool rotatable and having a plurality of elements radially therefrom, the elements extendable with the application of pressurized fluid.

According to another aspect of the present invention there is provided a method of profiling a pipe or other hollow tubular article, the method comprising the steps of applying a roller means to a part of the pipe bore selected to be profiled, translating the roller means across the bore in a direction including a circumferential component while applying a force provided by fluid pressure to the roller means in a radially outwards direction with respect to the longitudinal axis of the pipe, and continuing such translation and force application until the pipe is plastically deformed substantially into the intended profile.

l0a According to another aspect of the present invention there is provided a method of conjoining two pipes or other hollow tubular articles, the method comprising the steps of locating one of the two pipes within and longitudinally overlapping one of the other of the two pipes, applying roller means to a part of the bore of the inner of the two pipes at a location where it is intended that the two pipes be conjoined, translating the roller means across the bore in a direction including a circumferential component while applying a radially outwardly directed force provided by fluid pressure to the roller means, and continuing such translation and force application until the inner pipe is plastically deformed into permanent contact with the outer pipe and is thereby conjoined thereto.

According to a further aspect of the present invention there is provided an apparatus for expanding a pipe or other hollow tubular article, the apparatus comprising roller means constructed or adapted for rolling deployment against the bore of the pipe, the roller means comprising at least one set of individual rollers each mounted on a readily extendable member operated by fluid pressure, the at least one set of individual rollers for rotation about a respective rotation axis which is generally parallel to the longitudinal axis of the apparatus, the rotation axes of the at least one set of rollers being circumferentially distributed around the expansion apparatus and each being radially offset from the longitudinal axis of the expansion apparatus, the expansion apparatus being selectively rotatable around its longitudinal axis.

lOb According to a further aspect of the present invention there is provided an apparatus for profiling or conjoining pipes or other hollow tubular articles, the apparatus comprising roller means and radial urging means selectively operable to urge the roller means radially outwards of a longitudinal axis of the apparatus, the radial urging means being operated by fluid pressure, the radial urging means causing or allowing the roller means to move radially inwards towards the longitudinal axis of the apparatus when the radial urging means is not operated, the roller means comprising a plurality of individual rollers each mounted for rotation about a respective rotation axis which is substantially parallel to the longitudinal axis of the apparatus, the rotation axes of the individual rollers being circumferentially distributed around the apparatus and each the rotation axis being radially offset from the longitudinal axis of the apparatus, the apparatus being selectively rotatable around its longitudinal axis to translate the roller means across the bore of a pipe against which the roller means is being radially urged.
According to a further aspect of the present invention there is provided a method of expanding an inner pipe into an outer pipe, the method comprising providing a body having expander members which are extendable therefrom under fluid pressure to cause the rolling compressive yield of the wall, and extending the expander members to cause rolling compressive yield of the wall of the inner pipe wall to cause reduction in wall thickness and subsequent increase in circumference resulting in diameter increase.

lOc According to a further aspect of the present invention there is provided a method of creating a high pressure seal between an inner pipe and an outer pipe by creating a metal to metal interface between the pipes by effecting rolling compressive yield of the inner pipe within the outer pipe by fluid pressure.

According to a further aspect of the present invention there is provided an apparatus for expanding a tubular in a wellbore, comprising a tubular run-in string to transport the apparatus into the wellbore and to provide fluid thereto, and an expander tool, disposable in the tubular, the expander tool rotatable and having a plurality of elements radially therefrom, the elements extendable with the application of pressurized fluid.

According to a further aspect of the present invention there is provided a method of profiling a pipe or other hollow tubular article in a wellbore, the method comprising the steps of applying a roller means to a part of the pipe bore selected to be profiled, translating the roller means across the bore in a direction including a circumferential component while applying a force to the roller means in a radially outwards direction with respect to the longitudinal axis of the pipe, and continuing such translation and force application until the pipe is plastically deformed substantially into the intended profile.

According to a further aspect of the present invention there is provided an apparatus for expanding a pipe or other hollow tubular article in a wellbore, the apparatus comprising roller means constructed or adapted for rolling 10d deployment against the.bore of the pipe, the roller means comprising at least one set of individual rollers each mounted for rotation about a respective rotation axis which is generally parallel to the longitudinal axis of the apparatus, the rotation axes of the at least one set of rollers being circumferentially distributed around the expansion apparatus and each being radially offset from the longitudinal axis of the expansion apparatus, the expansion apparatus being selectively rotatable around its longitudinal axis.

According to a further aspect of the present invention there is provided an apparatus for profiling or conjoining pipes or other hollow tubular articles in a wellbore, the apparatus comprising roller means and radial urging means selectively operable to urge the roller means radially outwards of a longitudinal axis of the apparatus, the radial urging means causing or allowing the roller means to move radially inwards towards the longitudinal axis of the apparatus when the radial urging means is not operated, the roller means comprising a plurality of individual rollers each mounted for rotation about a respective rotation axis which is substantially parallel to the longitudinal axis of the apparatus, the rotation axes of the individual rollers being circumferentially distributed around the apparatus and each the rotation axis being radially offset from the longitudinal axis of the apparatus, the apparatus being selectively rotatable around its longitudinal axis to translate the roller means across the bore of a pipe against which the roller means is being radially urged.
According to a further aspect of the present invention there is provided a method of expanding an inner pipe into 10e an outer pipe in a wellbore, the method comprising effecting rolling compressive yield of the wall of the inner pipe wall to cause reduction in wall thickness and subsequent increase in circumference resulting in diameter increase.

According to a further aspect of the present invention there is provided a method for profiling a pipe or other hollow tubular article comprising applying a roller system to a part of a pipe bore selected to be profiled, wherein the roller system comprises an annular body having a longitudinal bore disposed there-through, one or more recesses formed in an outer surface of the body, and one or more rollers each mounted on one or more slideable pistons, wherein the pistons are sealably disposed within the one or more recesses, translating the roller system across the bore in a direction including a circumferential component while applying a force to the roller system in a radially outwards direction with respect to a longitudinal axis of the pipe, and continually applying and translating until the pipe is plastically deformed substantially into the intended profile.

According to a further aspect of the present invention there is provided a method for conjoining two pipes or other hollow tubular articles, comprising locating at least a portion of a first pipe within and longitudinally overlapping at least a portion of a second pipe, applying a roller system to an inner surface of the first pipe at a location where the first and second pipes are to be conjoined, wherein the roller system comprises an annular body having a longitudinal bore disposed there-through, one or more recesses formed in an outer surface of the body, l Of and one or more rollers each mounted on one or more slideable pistons, wherein the pistons are sealably disposed within the one or more recesses, translating the roller system across the bore of the first pipe in a direction including a circumferential component while applying a radially outwardly directed force to the rollers, and continually applying and translating until the first pipe is plastically deformed into permanent contact with the second pipe and is thereby conjoined thereto.
According to a further aspect of the present invention there is provided an apparatus for expanding a tubular article, comprising an annular body having a longitudinal bore disposed there-through, one or more recesses formed in an outer surface of the body, and one or more rollers each mounted on one or more slideable pistons, wherein the pistons are sealably disposed within the one or more recesses.

According to a further aspect of the present invention there is provided an apparatus for expanding a tubular article, comprising an annular body having a longitudinal bore disposed there-through, one or more recesses formed in an outer surface of the body, and one or more roller assemblies, each comprising a roller mounted on a slideable piston, wherein each roller assembly is sealably disposed within each one or more recesses.

According to a further aspect of the present invention there is provided an apparatus for profiling tubular articles comprising roller means, and radial urging means selectively operable to urge the roller means radially outwards of a longitudinal axis of the apparatus, the .lOg radial urging means causing or allowing the roller means to more radially inwards towards the longitudinal axis of the apparatus when the radial urging means is not operated, wherein the radial urging means comprises a respective piston on which each the roller is individually rotatably mounted, each the piston being slidably sealed in a respective radially extending bore formed in a body of the apparatus, a radially inner end of each the bore being in fluid communication with fluid pressure supply means selectively pressurisable to operate the radial urging means, and wherein the roller means comprises a plurality of individual rollers each mounted for rotation about a respective rotation axis which is substantially parallel to the longitudinal axis of the apparatus, the rotation axes of the individual rollers being circumferentially distributed around the apparatus and each the rotation axis being radially offset from the longitudinal axis of the apparatus, the apparatus being selectively rotatable around its longitudinal axis to translate the roller means across the bore of a pipe against which the roller means is being radially urged.

According to a further aspect of the present invention there is provided a method for profiling a pipe or other hollow tubular article comprising applying a roller system to a part of a pipe bore selected to be profiled, wherein the roller system comprises an annular body having a longitudinal bore disposed there-through, one or more recesses formed in an outer surface of the body, and one or more rollers each mounted on one or more slideable pistons, wherein the pistons are operable in a compliant manner, translating the roller system across the bore in a direction including a circumferential component while 10h applying a force to the roller system in a radially outwards direction with respect to a longitudinal axis of the pipe, and continually applying and translating until the pipe is plastically deformed substantially into the intended profile.

According to a further aspect of the present invention there is provided a method for conjoining two pipes or other hollow tubular articles, comprising locating at least a portion of a first pipe within and longitudinally overlapping at least a portion of a second pipe, applying a roller system to an inner surface of the first pipe at a location where the first and second pipes are to be conjoined, wherein the roller system comprises an annular body having a longitudinal bore disposed there-through, one or more recesses formed in an outer surface of the body, and one or more compliant rollers each mounted on one or more slideable pistons, translating the roller system across the bore of the first pipe in a direction including a circumferential component while applying a radially outwardly directed force to the rollers, and continually applying and translating until the first pipe is plastically deformed into permanent contact with the second pipe and is thereby conjoined thereto.

According to a further aspect of the present invention there is provided a method for conjoining two pipes or other hollow tubular articles, comprising locating at least a portion of a first pipe within and longitudinally overlapping at least a portion of a second pipe, applying a compliant roller system to an inner surface of the first pipe at a location where the first and second pipes are to be conjoined, wherein the roller system comprises an 1ol annular body having a longitudinal bore disposed there-through, one or more recesses formed in an outer surface of the body, and one or more rollers each mounted on one or more slideable pistons, translating the roller system across the bore of the first pipe in a direction including a circumferential component while applying a compliant, radially outwardly directed force to the rollers, and continually applying and translating until the first pipe is plastically deformed into permanent contact with the second pipe and is thereby conjoined thereto.

According to a further aspect of the present invention there is provided an apparatus for compliantly expanding a tubular article, comprising an annular body having a longitudinal bore disposed there-through, one or more recesses formed in an outer surface of the body, and one or more compliant rollers each mounted on one or more slideable members that are radially extendable from the one or more recesses.

According to a further aspect of the present invention there is provided an apparatus for expanding an inner and outer diameter of a wellbore tubular, comprising an annular body having a longitudinal bore disposed there- through, one or more roller assemblies, each comprising an independently extendable roller mounted on a slideable member, and wherein the members are slideable with fluid pressure applied thereto.

According to a further aspect of the present invention there is provided an apparatus for enlarging an inner and outer diameter of wellbore tubulars comprising roller means, and radial urging means selectively operable to urge i oj the roller means radially in a compliant manner outwards of a longitudinal axis of the apparatus, the radial urging means causing or allowing the roller means to move radially inwards towards the longitudinal axis of the apparatus when the radial urging means is not operated.

According to a further aspect of the present invention there is provided a method of expanding a tubular in a wellbore comprising expanding a first tubular in at least one location, whereby an outer wall of the tubular is in frictional contact with an inner wall of the wellbore therearound, and completing the expansion of the first tubular into a substantially circumferential contact with the inner wall whereby at least one fluid path remains between the first tubular and the inner wall after expanding the first tubular and before completing the expansion.

According to a further aspect of the present invention there is provided a method for profiling a pipe or other hollow tubular article comprising applying an expander system to a part of a pipe bore selected to be profiled, wherein the expander system comprises an annular body, one or more recesses formed in an outer surface of the body,and one or more expanders each mounted on one or more slidable pistons, translating the expander system across the bore in a direction including a circumferential component while applying a force to the expander system in a radially outwards direction with respect to a longitudinal axis of the pipe, and continually applying and translating until the pipe is plastically deformed substantially into the intended profile.

10k According to a further aspect of the present invention there is provided A method for conjoining two pipes or other hollow tubular articles, comprising locating at least a portion of a first pipe within and longitudinally overlapping at least a portion of a second pipe, applying an expander system to an inner surface of the first pipe at a location where the first and second pipes are to be conjoined, wherein the expander system comprises an annular body, one or more recesses formed in an outer surface of the body, and one or more expanders each mounted on one or more slidable pistons, translating the expander system across the bore of the first pipe in a direction including a circumferential component while applying a radially outwardly directed force to the expanders, and continually applying and translating until the first pipe is plastically deformed into permanent contact with the second pipe and is thereby conjoined thereto.

According to a further aspect of the present invention there is provided An apparatus for expanding a tubular article, comprising an annular body, one or more recesses formed in an outer surface of the body, and one or more expander assemblies, each comprising an expander mounted on a slidable piston, wherein each expander assembly is disposed within one of the one or more recesses.

According to a further aspect of the present invention there is provided An apparatus for compliantly expanding a tubular article, comprising an annular body, one or more recesses formed in an outer surface of the body, and one or more compliant expanders each mounted on one or more slideable members that are radially extendable from the one or more recesses.

According to a further aspect of the present invention there is provided a method of expanding a tubular in a wellbore comprising expanding a first tubular in at least one location whereby at least one fluid path remains between the first tubular and an inner wall of the wellbore therearound, and completing the expansion of the first tubular thereby substantially closing the at least one fluid path.

According to a further aspect of the present invention there is provided a method of expanding a tubular in a wellbore comprising expanding a first tubular.in at least one location whereby at least one fluid path remains between the first tubular and an inner wall of the wellbore therearound, and completing the expansion of the first tubular'whereby the tubular is substantially circular in cross section.

According to a further aspect of the present invention there is provided a method of completing a wellbore comprising forming an enlarged inner diameter at the bottom of a first tubular through expansion, placing the top of a second tubular adjacent the enlarged inner diameter, and expanding a top portion of the second tubular into frictional contact with an interior surface of the enlarged inner diameter at the bottom of the first tubular.
According to a further aspect of the present invention there is provided a method of completing a wellbore comprising expanding a first tubular to a desired monobore I Om diameter, forming an enlarged inner diameter at the bottom of the first tubular through expansion, lowering a second tubular through the first tubular, placing the top of the second tubular adjacent the enlarged inner diameter at the bottom of the first tubular, expanding the top of the second tubular into frictional contact with an interior surface of the enlarged inner diameter, and expanding the second tubular to the desired monobore diameter.
According to a further aspect of the present invention there is provided a method of completing a wellbore comprising expanding a bottom portion of a first tubular with a hydraulically actuated tool, wherein the hydraulically actuated tool comprises an annular body having a longitudinal bore disposed there-through, one or more radially extendable members mounted on one or more slidable pistons, the piston having a piston surface on the underside thereof.

According to a further aspect of the present invention there is provided a method of forming a seal between two tubular members, the method comprising providing a first tubular member having an internal surface and an external surface, the external surface describing a first diameter, providing at least one recess in the external surface at a seal portion of the first tubular member, locating a deformable sealing member in the recess such that the sealing member describes an external diameter no greater than the first diameter, locating the first tubular member within a second tubular member, and expanding at least the seal portion of the first tubular member such that the lOn sealing member engages an inner surface of the second tubular member.

According to a further aspect of the present invention there is provided a seal-forming arrangement comprising a first tubular member having an internal surface, and an external surface describing a first diameter, the tubular member defining at least one recess in the external surface at a deformable seal portion of the first tubular member, the seal portion having a wall thickness substantially equal to the wall thickness of the tubular member adjacent the seal portion, and a deformable sealing member in the recess, the sealing member describing an external diameter no greater than the first diameter, wherein expansion of at least the seal portion of the first tubular member increases the diameter of the sealing member to at least the first diameter.

According to a further aspect of the present invention there is provided an apparatus for expanding a down hole tubular comprising a body, at least one radially extendable member operatively connected to the body and being radially extendable therefrom, the at least one radially extendable member having a first extended position and a second lesser extended position, and a biasing mechanism for biasing the at least one radially extendable member toward the first extended position.

According to a further aspect of the present invention there is provided an apparatus for expanding a down hole tubular comprising a body, at least one radially extendable member operatively connected to the body and being radially lOo extendable therefrom, the at least one radially extendable member having a first extended position and being movable radially inward therefrom, and a biasing mechanism for biasing the at least one radially extendable member toward the first extended position.

According to a further aspect of the present invention there is provided a method for expanding a wellbore tubular comprising providing an expander having at least one radially extendable member, the radially extendable member having a first unextended position, a second fully extended position and a range of positions between the first and second positions wherein the radially extendable moves form the first position upon application of force to the radially extendable member, locating the expander proximate the wellbore tubular, applying the force to the radially extendable member, engaging the radially extendable member with an inner diameter of the wellbore tubular, and expanding the tubular wherein the radially extendable member is positioned within range for at least a portion of the expansion.

According to a further aspect of the present invention there is provided a method for expanding a wellbore tubular comprising providing an expander having at least one radially extendable member, the radially extendable member having a first unextended position, a second fully extended position and a range of positions between the first and second positions wherein the radially extendable member moves from the first position upon application of a force to the radially extendable member and wherein at least a portion of the force remains applied during the expanding, locating the expander proximate the well bore tubular, lOp applying the force to the radially extendable member and maintaining at least a portion of the applied force, engaging the radially extendable member with an inner diameter of the well bore tubular, and expanding the tubular wherein the radially extendable member is positioned within the range for at least a portion of the expansion.

According to a further aspect of the present invention there is provided an apparatus for expanding a well bore tubular comprising a body, at least one radially extendable member operatively connected to the body, the radially extendable member having a first unextended position, a second fully extended position and a range of positions between the first and second positions wherein the radailly extendable member is movable from the first position upon application of a force to the radially extendable member, and a force storage mechanism for storing at least a portion of the force.

According to a further aspect of the present invention there is provided a tool for expanding a tubular comprising a primary expander portion for initially expanding the tubular to a first diameter, and a secondary, compliant expander portion for expanding the tubular to a second larger diameter, the secondary expand portion being compliant in response to inwardly directed forces and capable of assuming an outer diameter equal to an outer diameter of the primary expander portion.

According to a further aspect of the present invention there is provided a method of expanding a tubular of differing characteristics, the method comprising expanding 10q a first portion of the tubular with a first set of characteristics to a first diameter, expanding a second portion of the tubular with a second set of characteristics to a second diameter, whereby the diameters are determined by the characteristics of the tubular.

According to a further aspect of the present invention there is provided a two step method of expanding a tubular in a wellbore comprising initially expanding the tubular with a fixed expansion member, and additionally expanding the tubular with a compliant expansion member.

According to a further aspect of the present invention there is provided an expander tool for increasing the diameter of a tubular in a wellbore, the tool comprising a non compliant portion for initially expanding the tubular, and a compliant portion for compliantly expanding the tubular.

According to a further aspect of the present invention there is provided a compliant expander assembly including a body, at least radially extendable expander members disposed about the body, each expander member having a retracted and an extended position and each member having a piston surface for moving the member to the extended position with a pressurized fluid, wherein, the extended position, the expander members operate to permit radially inward movement due to inwardly directed forces from an adjacent wellbore.

According to a further aspect of the present invention there is provided a method of expanding pipes in a wellbore, comprising placing a smaller diameter pipe in an 10r overlapping arrangement in the wellbore with a larger diameter pipe, and expanding the pipes radially in an area of overlap whereby the smaller and larger diameter pipes are deformed plastically into a wall of the wellbore therearound.

According to a further aspect of the present invention there is provided an apparatus for expanding a wellbore tubular, comprising a body, and at least one radially extendable member selectively movable outwardly from the body by the application of a controllable force thereto.
According to a further aspect of the present invention there is provided a method for expanding a wellbore tubular, comprising providing an expander having at least one radially extendable member selectively movable outwardly from a first unextended position upon application of controllable force thereto, locating the expander proximate the wellbore tubular, applying the force to the radially extendable member, engaging the radially extendable member with an inner diameter of the wellbore tubular, and expanding the tubular.

According to a further aspect of the present invention there is provided a method of completing a wellbore comprising forming an enlarged inner diameter portion at the bottom of a first tubular through expansion, placing the top of a second tubular adjacent the enlarged inner diameter, and expanding a top portion of the second tubular into frictional contact with an interior surface of the enlarged inner diameter portion at the bottom of the first tubular.

lOs According to a further aspect of the present invention there is provided a method of expanding a tubular in a wellbore comprising expanding a first tubular in at least one location whereby at least one fluid path remains between the first tubular and an inner wall of the wellbore therearound, and completing the expansion of the first tubular thereby substantially closing the at least one fluid path.

According to a further aspect of the present invention there is provided a method of sealing an annular area in a wellbore, comprising providing a tubular member, and deforming the tubular member in a manner whereby an outer surface of the tubular member assumes a shape of a non-uniform surrounding surface and forms a seal therebetween.
According to a further aspect of the present invention there is provided a method of conjoining two pipes in a wellbore or other hollow tubular articles in a wellbore, the method comprising the steps of locating one of the two pipes within and longitudinally overlapping one of the other of the two pipes, applying roller means to a part of the bore of the inner of the two pipes at a location where_ it is intended that the two pipes be conjoined, translating the roller means across the bore in a direction including a circumferential component while applying a radially outwardly directed force to the roller means, and continuing such translation and force application until the inner pipe is plastically deformed into permanent contact with the outer pipe and is thereby conjoined thereto.

lOt 1 According to a further aspect of the present invention ~ 2 there is provided a method of creating a high pressure seal 3 between an inner pipe and an outer pipe in a wellbore by 4 creating a metal to metal interface between the pipes by effecting rolling compressive yield of the inner pipe 6 within the outer pipe.

8 In another aspect, the invention provides a method of 9 forming a seal between two tubular members, the method comprising:
11 providing a first tubular member having an iriternal 12 surface and an external surface, the external surface 13 describing a first diameter;
14 providing at least one recess in said external surface at a seal portion of the first tubular member, said seal 16 portion having a wall thickness substantially equal to the 17 wall thickness of the tubular member adjacent said seal 18 portion;
19 locating a deformable sealing member in the recess such that the sealing member describes an external diameter no 21 greater than said first diameter;
22 locating the first tubular member within a second tubular 23 member; and 24 expanding at least the seal portion of the first tubular member such that the sealing member engages an inner 26 surface of the second tubular member.

28 Embodiments of the invention will now be described by 29 way of example, with reference to the accompanying .30 drawings wherein Fig. 1 is a plan view of_a first embodiment.

of profiling tool;

lOu 1 Fig. 2 is an elevation of the profiling tool 2 of Fig. 1;

Fig. 3 is a sectional perspective view of the profiling tool of Figs. 1 & 2, the section being taken on the line III-III in Fig. 2;
6 Fig. 4 is an exploded perspective view of the 7 profiling tool of Figs. 1-4;

Figs. 5A, 5B, & 5C are simplified sectional 9 views of three successive stages of operation of the profiling tool of Figs. 1-4;

12 Fig. 6 is a schematic diagram illustrating 13 the metallurgical principle underlying the 14 operational stage depicted in Fig. 5C;

1 Figs. 7A & 7B are illustrations corresponding 2 to Figs. 5A & 53 but in respect of a variant 3 of the Figs. 1-4 profiling tool having two 4 rollers instead of three;

Figs. 8A & 89 are illustrations corresponding 6 to Figs. 5A & 5B but in respect of a variant 7 of the Figs. 1-4 profiling tool having five 8 rollers instead of three;

9 Figs. 9A & 9B respectively illustrate starting and finishing stages of a first 11 practical application of the profiling tool 12 of Figs. 1-4;

13 Figs. l0A & 10B respectively illustrate 14 starting and finishing stages of a second practical application of the profiling tool 16 of Figs. 1-4;

17 Figs. 11A & 11B respectively illustrate 18 starting and finishing stages of a third 19 practical application of the profiling tool of Figs. J-4; , , 21 Figs. 12A & 12B respectively illustrate 22 starting and finishing stages of a fourth 23 practical application of the profiling tool 24 of Figs. 1-4;

Figs. 13A & 13B respectively illustrate 26 starting and finishing stages of a fifth 27 practical application of the profiling tool 28 of Figs. 1-4;

1 Figs. 14A & 14B respectively illustrate 2 starting and finishing stages of a sixth 3 practical application of the profiling tool 4 of Figs. 1-4;

Figs. 15A & 152 respectively illustrate 6 starting and finishing stages of a seventh 7 practical application of the profiling tool 8 of Figs. 1-4;

9 Figs. 16A & 16B respectively depict starting and finishing stages of an eighth practical 11 application of the profiling tool of Figs. 1-12 4;

13 Figs. 17A & 17B respectively depict starting 14 and finishing stages of a ninth practical application of the profiling tool of Figs. 1-16 4;

17 Fig. 18 schematically depicts a tenth 18 practical application of the profiling tool 19 of Figs. 1-4;

Fig. 19 schematically depiCts an eleventh 21 practical application of the profiling tool 22 of Figs. 1-4;

23 Fig. 20 is a longitudinal elevation of.a 24 first embodiment of expansion tool in accordance with the present invention; -27 Fig. 21 is a longitudinal elevation, to'an 28 enlarged scale, of part of the expansion tool 29 of Fig. 20;

1 Fig. 21A is an exploded view of the tool part 2 illustrated in Fig. 20;

3 Fig. 22 is a longitudinal section of the tool 4 part illustrated in Fig. 20;

Fig. 23 is a longitudinal section of the 6 expansion tool illustrated in Fig. 21;

7 Fig. 24 is an exploded view of part of the 8 expansion tool illustrated in Fig. 20;

9 Fig. 25 is a longitudinal section of an alternative form of the tool part illustrated 11 in Fig. 21;

12 Fig. 26 is a longitudinal section of a 13 technical variant of the tool part 14 illustrated in Fig. 21;

Fig. 27 is a longitudinal elevation ot a 16 second embodiment of expansion tool in 17 accordance with the present invention;
18 Figs. 28A, 28B, & 28C are respectively a 19 longitudinal section, a longitudinal elevation, and a simplified end view of a 21 , third embodiment of expansion tool in 22 accordance with the present invention;

23 Figs. 29A & 29B are longitudinal sections of 24 a fourth embodiment of expansion tool in accordance with the present invention, = .
26 respectively in expanded and contracted 27 configurations; and 1 Fig. 30 is a longitudinal section of a fifth 2 embodiment of expansion tool in accordance 3 with the present invention.

4 Referring first to Figs. 1 & 2, these depict a three-roller profiling tool 100 in accordance with the 6 present invention. The tool 100 has a body 102 which 7 is hollow and generally tubular, with conventional 8 screw-threaded end connectors 104 & 106 for connection 9 to other components (not shown) of a downhole assembly.
The end connectors 104 & 106 are of reduced diameter il (compared to the outside diameter of the longitudinally 12 central body part 108 of the tool 100), and together 13 with three longitudinal flutes 110 on the central body 14 part 108, allow the passage of fluids along the outside of the tool 100. The central body part 108 has three 16 lands 112 defined between the three flutes 110, each 17 land 112 being formed with a respective recess 114 to 18 hold a respective roller 116 (see also Figs. 3 & 4)_ 19 Each of the recesses 114 has parallel sides and extends radially from the radially perforated tubular core 115 21 of the tool 100 to the exterior of the respective land 22 112. Each of the mutually identical rollers 116 is 23 near-cylindrical and slightly barrelled (i.e. of sligh-,24 tly greater diameter in its longitudinally central region than at either longitudinal end, with a 26 generally convex profile having a discontinuity-free 27 transition between greatest and least diameters). Each 28 of the rollers 116 is mounted by means of a bearing 118 29 at each end of the respective roller for rotation about a respective rotation axis which is parallel ta the 31 longitudinal axis of the tool 100 and radially offset 32 therefrom at 120-degree mutual circumferential 33 separations around the central part 108. The bearings 34 118 are formed as integral end members of radially 1 slidable pistons 120, one piston 120 being slidably 2 sealed within each radially extending recess 114. The 3 inner end of each piston 120 is exposed to the pressure 4 of fluid within the hollow core of the tool 100 by way 5 of the radial perforations in the tubular core 115; in 6 use of the tool 100, this fluid pressure will be the 7 downhole pressure of mud or other liquid within a 8 drillstring or coiled tubing at or near the lower end 9 of which the toll 100 will be mounted. Thus by

10 suitably pressurising the core 115 of the tool 100, the

11 pistons 120 can be driven radially outwards with a

12 controllable force which is proportional to the

13 pressurisation, and thereby the piston-mounted rollers

14 116 can be forced against a pipe bore in a manner to be

15 detailed below. Conversely, when the pressurisation of

16 the core 115 of the tool 100 is reduced to below

17 whatever is the ambient pressure immediately outside

18 the tool 100, the pistons 120 (together with the

19 piston-mounted rollers 116) are allowed to retract radially back into their respective recesses 114.
21 (Such retraction can optionally be encouraged by 22 suitably disposed springs (not shown)).

23 The principles by which the profiling tool 100 24 functions will now be detailed with reference to Figs.
5 and 6.

26 Fig. 5A is a schematic end view of the three rollers 27 116 within the bore of an inner pipe 180, the remainder 28 of the tool 100 being omitted for the sake of clarity.
29 The pipe 180 is nested within an outer pipe 190 whose internal diameter is somewhat greater than the outside 31 diameter of the inner pipe 180. As depicted.in Fig.
32 5A, the core of the tool 100 has been pressurised just 33 sufficiently to push the pistons 120 radially outwards 1 and thereby to bring the piston-mounted rollers 116 2 into contact with the bore of the inner pipe 180, but 3 without at first exerting any significant forces on the 4 pipe 180.

Fig. 53 depicts the next stage of operation of the 6 profiling tool 100, in which the internal 7 pressurisation of the tool 100 is increased 8 sufficiently above its external pressure (i.e. the 9 pressure in the region between the exterior of the tool 100 and the bore of the pipe 180) such that the rollers 11 116 each exert a substantial outward force, as denoted 12 by the arrow-headed vectors superimposed on each roller 13 116 in Fig. 5B. The effect of such outward forces on 14 the rollers 116 is circumferentially to deform the wall of the inner pipe 180 (with concomitant distortion of 16 the pipe 180 which is shown in Fig. 5B for the sake of 17 clarity). When the roller-extended lobes touch the 18 bore of the outer pipe 190, the inner pipe 180 is 19 thereby anchored against rotation with respect to the outer pipe 190, or at least constrained against free 21 relative rotation. By simultaneously rotating the 22 tool 100 around its longitudinal axis (which will 23 normally be substantially coincident with the 24 longitudinal axis of the pipe 180), the circumferential deformation of the wall of the pipe 180 tends to become 26 uniform around the pipe 180, and the pipe 180 27 circumferentially extends into substantially uniform 28 contact with the bore of the outer pipe 190, as 29 depicted in Fig. 5C. This occurs due to the rollers causing rolling compressive yield of the inner pipe 31 wall to cause reduction in wall thickness, increase in 32 circumference and consequent increase in diameter.
33 (Rotation of the tool 100 can be undertaken by any 34 suitable procedure, several of which will subsequently 1 be described). Circumferential deformation of the pipe 2 180 is initially elastic and may subsequently be 3 plastic. A secondary effect of the process is to 4 generate compressive hoop stress in the internal portion of the inner tube and an interference fit 6 between the inner tube and the outer tube.

7 From the stage depicted in Fig. 5C wherein the inner 8 pipe 180 has initially been circumferentially deformed 9 just into full contact with the bore of the outer pipe 190 (thus removing the previous clearance between the 11 pipes 180 and 190) but without stretching or distortion 12 of the outer pipe 190, continued (and possibly 13 increased) internal pressurisation of the tool 100 in 14 conjunction with continued rotation of the tool 100 (at the same rotational speed or at a suitably different 16 rotational speed) forces the inner pipe 180 outwards 17 against the resistance to deformation of the outer pipe 18 190. Since the inner pipe 180 is now backed by the 19 outer pipe 190 with respect to the radially outward forces being applied by the rollers 116 such that the 21 wall of the inner pipe 180 is now pinched between the 22 rollers 116 and the outer pipe 190, the mechanism of 23 deformation of the pipe 180 changes to compressive 24 extension by rolling (i.e. the same thinning/extension principle as prevails in conventional steel rolling 26 mills, as schematically depicted in Fig. 6 wherein the 27 circular rolling of Figs. 5A-5C has been opened out and 28 developed into an equivalent straight-line rolling 29 procedure to enhance the analogy with steel rolling mills).

31 When operation of the tool 100 is terminated.and the 32 rbllers 116 are caused or allowed to retract radially 33 into the body of the tool 100 thereby to relieve the 1 pipes 180 of all contact with the rollers 116, the 2 induced compressive hoop stress created in the wall of 3 the inner pipe 180 due to the rolling process causes 4 the inner pipe 180 to remain in contact with the inner wall of the outer pipe 190 with very high contact 6 stresses at their interface.

7 Figs. 7A & 7B correspond to Figs. 5A & SB, and 8 schematically depict the equivalent stages of operation 9 of a two-roller profiling tool (not otherwise shown per se) in order to illustrate the effects of using a 11 profiling tool having fewer than the three rollers of 12 the profiling tool 100 detailed above.

13 Figs. BA & 8B also correspond to Figs. 5A & SB, and 14 schematically depict the equivalent stages of operation of a five-roller profiling tool (not otherwise shown 16 per se) in order to illustrate the effects of using a 17 profiling tool having more than the three rollers of 18 the profiling tool 100 detailed above.

19 It should be noted that though the very high contact stresses existing at the interface of the inner pipe 21 180 and outer pipe 190 may cause the outer pipe 190 to 22 expand elastically or plastically, it is not a 23 requirement of this process that the outer pipe 190 is 24 capable of any expansion whatsoever. The process would still result in the high contact stresses between the 26 inner pipe=180 and the outer pipe 190 even if the outer 27 pipe 190 was incapable of expansion, eg by being thick 28 walled, by being encased in cement, or being tightly 29 embedded in a rock formation.

various practical applications of profiling tools in 31 accordance with the invention will now be described 1 with reference to Figs. 9 - 19. The profiling tool 2 used in these practical applications may be the 3 profiling tool 100 detailed above, or some variant of 4 such a profiling tool which differs in one or more details without departing from the scope of the 6 invention.

7 Fig. 9A schematically depicts the upper end of a first 8 pipe or casing 200 concentrically nested within the 9 lower end of a second pipe or casing 202 whose bore (internal diameter) is marginally greater than the 11 outside diameter of the first pipe or casing 200. A
12 profiling tool (not shown) is located within the upper 13 end of the first pipe or casing 200 where it is 14 overlapped by the second pipe or casing 202. The rollers of the profiling tool are then radially 16 extended into contact with the bore of the inner pipe 17 or casing 200 by means of internal pressurisation of 18 the profiling tool (or by any other suitable means 19 which may alternatively be utilised for forcing the rollers radially outwards of the profiling tool). The 21 outward forces exerted by the rollers on the bore of 22 the first pipe or casing 200 are schematically depicted 23 by the force-vector-depicting arrows 204.

24 From the starting situation depicted in Fig. 9A, combined with suitable rotation of the profiling tool 26 about its longitudinal axis (which is substantially 27 coincident with the longitudinal axis of the first pipe 28 or casing 200), the finish situation schematically 29 depicted in Fig. 9B is arrived at, namely the upper end of the inner pipe or casing 200 is profiled by 31 permanent plastic expansion into conjunction.with the 32 lower end of the second pipe or casing 202. Thereby 33 the two pipes or casings are permanently conjoined 1 without the use of any form of separate connector and 2 without the use of conventional joining techniques such 3 as welding.

4 Figs. 10A & 109 correspond to Figs. 9A & 9B
5 respectively, and schematically illustrate an optional 6 modification of the profiling/conjoining technique 7. described with respect to Figs. 9A & 9B. The 8 modification consists of applying an adherent coating 9 206 of hard particulate material to the exterior of the 10 upper end of the first (inner) pipe or casing 200 prior 11 to its location within the lower end of the second 12 (outer) pipe or casing 202. The hard particulate 13 material may consist of carbide granules, e.g. tungsten 14 carbide granules such as are commonly used to coat 15 downhole reamers. In the application depicted in Figs.
16 10A & 10B, the hard particulate material is selected 17 for its crush resistance rather than for its abrasive 18 qualities, and in particular the material is selected 19 for its ability to interpenetrate the meeting surfaces

20 of two sheets of steel which are pressed together with

21 the hard particulate material sandwiched between the

22 steel components. Such sandwiching is schematically

23 depicted in Fig. lOB. Tests have shown a surprising

24 incre4se in resistance to separation forces of pipes or =
other articles conjoined by a profiling tool in 26 accordance with the invention to withstand, where a 27 coating of hard particulate material was first 28 interposed between the part:s being conjoined. It is 29 preferred that of the whole area to be coated, only a minority of the area is actually covered with the 31 particulate material, e.g. 10% of the area. (It is 32 believed that a higher covering factor actually reduces 33 the interpenetration effect and hence diminishes the 34 benefits below the optimum level).

1 Referring now to Figs. 11A & 11B, these schematically 2 depict an optional modification of the Fig. 9 3 conjoining procedure to achieve improved sealing 4 between the two conjoined pipes or casings. As depicted in Fig. 11A, the modification comprises 6 initially fitting the exterior of the first (inner) 7 pipe or casing 200 with a circumferentially extending 8 and part-recessed ductile metal ring 208, which may 9 (for example) be formed of a suitable copper alloy or a suitable tin/lead alloy. The modification also 11 comprises initially fitting the-exterior of the first 12 (inner) pipe or casing 200 with a circumferentially 13 extending and fully recessed elastomeric ring 210. As 14 depicted in Fig. 11B, the rings 208 and 210 become crushed between the two pipes or casings 200 & 202 16 after these have been conjoined by the profiling tool, 17 and thereby a mutual sealing is achieved which may be 18 expected to be superior to the basic Fig. 9 arrangement 19 in otherwise equal circumstances. In suitable situations, one or other of the sealing rings 208 and 21 210 may be omitted or multiplied to achieve a necessary 22 or desirable level of sealing (e.g. as in Fig. 12)_ 23 Referring now to Figs. 12A & 12B, these schematically 24 depict an arrangement in which the lower end of the second (outer) casing 202 is pre-formed to have a 26 reduced diameter so as to function as a casing hanger.
27 The upper end of the first (inner) casing 200 is 28 correspondingly pre-formed to have an increased 29 diameter which is complementary to the reduced diameter of the casing hanger formed at the lower end of the 31 outer casing 202, as depicted in Fig. 12A. Optionally, 32 the upper end of the first (inner) casing 200=may be 33 pfovided with an external seal in the form of an 34 elastomeric ring 212 flush-mounted in a circumferential 1 groove formed in the outer surface of the first casing 2 200. The arrangement of Fig. 12A differs from the 3 arrangement of Fig. 9A in that the latter arrangement 4 requires the pipe or casing 200 to be positively held up (to avoid dropping down the well out of its intended 6 position) until joined to the upper pipe or casing as 7 in Fig. 9B, whereas in the Fig. 12A arrangement the 8 casing hanger allows the inner/lower casing 200 to be 9 lowered into position and then released without the possibility of dropping out of position prior to the 11 two casings being conjoined by the profiling tool, as 12 depicted in Fig. 12B.

13 Referring now to Figs. 13A & 13B, these schematically 14 depict another optional modification of the Fig. 9 conjoining procedure in order to achieve a superior 16 resistance to post-conjunction separation. As depicted 17 in Fig. 13A, the modification consists of initially 18 forming the bore (inner surface) of the second (outer) 19 pipe or casing 202 with two circumferentially extending grooves 214 each having a width which reduces with 21 increasing depth. As depicted in Fig. 13B, when the 22 two pipes or casings 200 and 202 have been conjoined by 23 the profiling tool (as detailed with respect to Figs.
24 9A & 9$) , the first (innez) pipe or casing 20,0 will have been plastically deformed into the grooves 214, 26 thereby increasing the interlocking of the conjoined 27 pipes or casings and extending their resistance to 28 post-conjunction separation. While two grooves 214 are 29 shown in Figs. 13A & 13B by way of example, this procedure can in suitable circumstances be carried with 31 one such groove, or with three or more such grooves.
32 While each of the grooves 214 has been shown.with a 33 pieferred trapezoidal cross-section, other suitable 34 groove cross-sections can be substituted.

'aVO 00/37766 PCT/GB99/04225 1 The superior joint strength of the Fig. 13 arrangement 2 can be combined with the superior sealing function of 3 the Fig. 11 arrangement, as shown in Fig. 14. Fig. 14A
4 schematically depicts the pre-jointing configuration, in which the exterior of the first (inner) pipe or 6 casing 200 is fitted with a longitudinally spaced pair 7 of circumferentially extending and part-recessed 8 ductile metal rings 208, while the bore (inner surface) 9 of the second (outer) pipe or casing 202 is formed with l0 two circumferentially extending grooves 214 each having 11 a width which reduces with increasing depth. The 12 longitudinal spacing of the two grooves 214 is 13 substantially the same as the longitudinal spacing of 14 the seal rings 208. When the two pipes or casings are conjoined by use of the profiling tool (as 16 schematically depicted in Fig. 14B), the first (inner) 17 pipe or casing 200 is not only plastically deformed 18 into the corresponding grooves 214 (as in Fig. 13B), 19 but the metal rings 208 are crushed into the bottoms of these grooves 214 thereby to form high grade metal-to-21 metal seals.

22 In the arrangements of Figs. 9 - 14, it is assumed that 23 the second (outer) pipe or casing 202 undergoes little 24 or no permanent deformation, which may either be due to the outer pipe or casing 202 being inherently rigid 26 compared to the first (inner) pipe or casing 200, or be 27 due to the outer pipe or casing being rigidly backed 28 (e.g. by cured concrete filling the annulus around the 29 outer pipe or casing 202), or be due to a combination of these and/or other reasons. Fig. 15 schematically 31 depicts an alternative situation in which the second 32 (outer) pipe or casing 202 does not have the previously 33 assumed rigidity. As schematically depicted in Fig.
34 15A, the pre-jointing configuration is merely a variant 1 of the previously described pipe-joining arrangements, 2 in which the exterior of the upper end of the first 3 (inner) pipe or casing 200 is provided with two part-4 recessed metal seal rings 208 (each mounted in a respective circumferential groove), neither pipe being 6 otherwise modified from its initial plain tubular 7 shape. To conjoin the casings 200 and 202, the 8 profiling tool is operated in a manner which forces the 9 second (outer) casing 202 through its elastic limit and into a region of plastic deformation, such that when 11 the conjoining process is completed, both casings 12 retain a permanent outward set as depicted in Fig. 15B.
13 In each of the arrangements described with reference to 14 Figs. 9 - 15, the bore of the first pipe or casing 200 was generally smaller than the bore of the second pipe 16 or casing 202. However, there are situations where it 17 would be necessary or desirable that these bores be 18 about mutually equal following conjoining, and this 19 requires variation of the previously described arrangements, as will now be detailed.

21 In the arrangement schematically depicted in Fig. 16A, 22 the lower end of the second (outer) pipe or casing 202 23 is pre-formed to have an enlarged diameter, the bore 24 (inside diameter) of this enlarged end being marginally greater than the outside diameter of the first (inner) 26 pipe or casing 200 intended to be conjoined thereto.
27 The first (inner) pipe or casing 200 has initial 28 dimensions which are similar or identical to those of 29 the second pipe or casing 202 (other than for the enlarged end of the pipe or casing 202). Following use 31 of the profiling tool to expand the overlapping ends of 32 tfie two pipes or casings, both bores have about the 33 same diameter (as depicted in Fig. 16B) which has WO 00/37766 PC'T/GR99/04225 1 certain advantages (e.g. a certain minimum bore at 2 depth in a well no longer requires a larger or much 3 larger bore at lesser depth in the well). While 4 surface-level pipes can be extended in this manner 5 without difficulties in adding extra lengths of pipe, 6 special techniques may be necessary for feeding 7 successive lengths of casing to downhole locations when 8 extending casing in a downhole direction. (One 9 possible solution to this requirement may be provide 10 successive lengths of casing with a reduced diameter, 11 and to expand the entire length of each successive 12 length of casing to the uniform bore of previously 13 installed casing, this being achievable by further 14 aspects of the invention to be subsequently described 15 by way of example with reference to Figs. 20 et seq).
16 A modification of the procedure and arrangement of Fig.
17 16 is schematically depicted in Fig. 17 wherein the end 18 of the outer pipe or casing is not pre-formed to an 19 enlarged diameter (Fig. 17A). It is assumed in this 20 case that the profiling tool is capable of exerting 21 sufficient outward force through its rollers as to be 22 capable of sufficiently extending the diameter of the 23 outer pipe or casing simultaneously with the diametral 24 extension of the inner pipe or casing during forming of

25 the joint (Fig. 17B)

26 As well as conjoining pipes or casings, the profiling

27 tool in accordance with the invention can be utilised

28 for other useful purposes such as will now be detailed

29 with reference to Figs. 18 and 19.

In the situation schematically depicted in Fig. 18, a 31 riser 220 has a branch 222 which is to be blocked off 32 while continuing to allow free flow of fluid along the 1 riser 220. To meet this requirement, a sleeve 224 is 2 placed within the riser 220 in position to bridge the 3 branch 222. The sleeve 224 initially has an external 4 diameter which is just sufficiently less than the internal diameter of the riser 220 as to allow the 6 sleeve 224 to be passed along the riser to its required 7 location. Each end of the sleeve 224 is provided with 8 external seals 226 of any suitable form, e.g. the seals 9 described with reference to Fig. 11. When the sleeve 224 is correctly located across the branch 222, a 11 profiling tool (not shown in Fig. 18) is applied to 12 each end of the sleeve 224 to expand the sleeve ends 13 into mechanically anchoring and fluid-sealing contact 14 with the bore of the riser 220, thus permanently sealing the branch (until such time as the sleeve may 16 be milled away or a window may be cut through it).

17 Fig. 19 schematically depicts another alternative use 18 of the profiling tool in accordance with the invention, 19 in which a valve requires to be installed within plain pipe or casing 240 (i.e. pipe or casing free of landing 21 nipples or other means of locating and anchoring 22 downhole equipment). A valve 242 of a size to fit 23 within the pipe or casing 240 has a hollow tubular 24 - sleeve 244 welded-or otherwise secur6d to one end of 25 the valve. The sleeve 244 initially has an external 26 diameter which is just sufficiently less than the 27 internal diameter of the pipe or casing 240 as to allow 28 the mutually attached valve 242 and sleeve 244 to 29 passed down the pipe or casing 240 to the required location. The end of the sleeve 244 opposite to the 31 end attached to the valve 242 is provided with external 32 seals 246 of any suitable form, e.g. the seals 33 de'scribed with reference to Fig. 11. When the valve 34 242 is correctly located where it is intended to be 1 installed, a profiling tool (not shown in Fig. 19) is 2 applied to the end of the sleeve opposite the valve 242 3 to expand that end of the sleeve 244 into mechanically 4 anchoring and fluid-sealing contact with the bore of the pipe or casing 240. An optional modification of 6 the Fig. 19 arrangement is to attach an expandable 7 sleeve to both sides of the valve such that the valve 8 can be anchored and sealed on either side instead of 9 one side only as in Fig. 19.

Turning now to Fig. 20, this illustrates a side 11 elevation of an embodiment of expansion tool 300 in 12 accordance with the present invention. The expansion 13 tool 300 is an assembly of a primary expansion tool 302 14 and a secondary expansion tool 304, together with a connector sub 306 which is not essential to the 16 invention but which facilitates mechanical and 17 hydraulic coupling of the expansion tool 300 to the 18 downhole end of a drillstring (not shown) or to the 19 downhole end of coiled tubing (not shown). The primary expansion tool 302 is shown separately and to an 21 enlarged scale in Fig. 21 (and again, in exploded view, 22 in Fig. 21A). The expansion tool 300 is shown in 23 longitudinal section in Fig. 22, the primary expansion 24 tool 302 is shown separately in longitudinal section in Fig. 23, and the secondary expansion tool 304 is shown 26 separately in an exploded view in Fig. 24.

27 From Figs. 20 - 24 it will be seen that the general 28 form of the primary expansion tool 302 is that of a 29 roller tool externally presenting a conical array of four tapered rollers 310 tapering towards an imaginary 31 point (not denoted) ahead of the leading end=of the 32 expansion tool 300, i.e. the right end of the tool 300 33 as viewed in Figs. 20 & 21. As may be more clearly 1 seen in Figs. 21A, 22, & 23, the rollers 310 run on a 2 conical race 312 integrally formed on the surface of 3 the body of the primary expansion tool 302, the rollers 4 310 being constrained for true tracking by a longitudinally slotted cage 314. An end retainer 316 6 for the rollers 310 is secured on the screw-threaded 7 leading end 318 of the primary expansion tool 302 by 8 means of a ring nut 320. The trailing end 322 of the 9 primary expansion tool 302 is screw-threaded into the leading end 106 of the secondary expansion tool 304 to 11 form the composite expansion tool 300. Functioning of 12 the primary expansion tool 300 will be detailed 13 subsequently.

14 The secondary expansion tool 304 is substantially identical to the previously detailed profiling tool l00 16 (except for one important difference which is described 17 below), and accordingly those parts of the secondary 18 expansion tool 304 which are the same as corresponding 19 parts of the profiling tool 100 (or which are obvious modifications thereof) are given the same reference 21 numerals. The important difference in the secondary 22 expansion tool 304 with respect to the profiling tool 23 100 is that the rotation axes of the rollers 116 are no 24 longer'exactly parallel td the longitudinal axis of the tool, but are skewed such that each individual roller 26 rotation axis is tangential to a respective imaginary 27 helix, though making only a small angle with respect to 28 the longitudinal direction (compare Fig. 24 with Fig.
29 4). As particularly shown in Figs. 20 and 24, the direction (or "hand") of the skew of the rollers 116 in 31 the secondary expansion tool 304 is such that the 32 conventional clockwise rotation of the tool (as viewed 33 from,the uphole end of the tool, i.e. the left end as 34 viewed in Figs. 20 & 22) is such as to induce a 1 reaction against the bore of the casing (not shown in 2 Figs. 20 - 24) which tends not only to rotate the tool 3 300 around its longitudinal axis but also to advance 4 the tool 300 in a longitudinal direction, i.e. to drive the tool 300 rightwards as viewed in Figs. 20 & 22.
6 (The use of skewed bore-contacting rollers to cause a 7 rotating downhole tool to drive itself along a casing 8 is detailed in the afore-mentioned W093/24728-Al).

9 In use of the expansion tool 300 to expand casing (not shown) previously deployed to a selected downhole 11 location in a well, the tool 300 is lowered ori a 12 drillstring (not shown) or coiled tubing (not shown) 13 until the primary expansion tool 302 at the leading end 14 of the tool 300 engages the uphole end of the unexpanded casing. The core of the tool 300 is 16 pressurised to force the roller-carrying pistons 120 17 radially outwards and hence to force the rollers 116 18 into firm contact with the casing bore. The tool 300 19 is simultaneously caused to rotate clockwise (as viewed from its uphole end) by any suitable means (e.g. by 21 rotating the drillstring (if used), or by actuating a 22 downhole mud motor (not shown) through which the tool 23 300 is coupled to the drillstring or coiled tubing), 24 and this rotation combines with the skew of the rollers 116 of the secondary tool 304 to drive the tool 300 as 26 a whole in the downhole direction. The conical array 27 of rollers 310 in the primary expansion tool 302 forces 28 its way into the uphole end of the unexpanded casing 29 where the combination of thrust (in a downhole direction) and rotation rolls the casing into a conical 31 shape that expands until its inside diameter is just 32 greater than the maximum diameter of the array of 33 rollers 310 (i.e. the circumscribing diameter of the 34 array of rollers 310 at its upstream end). Thereby the 1 primary expansion tool 302 functions to bring about the 2 primary or initial expansion of the casing.

3 The secondary expansion tool 304 (which is immediately 4 uphole of the primary expansion tool 302) is internally 5 pressurised to a pressure which not only ensures that 6 the rollers 116 contact the casing bore with sufficient 7 force as to enable the longitudinal traction force to 8 be generated by rotation of the tool about its 9 longitudinal axis but also forces the pistons 120 10 radially outwards to an extent that positions the 11 piston-carried rollers 116 sufficiently radially 12 distant from the longitudinal axis of the tool 304 13 (substantially coincident with the centreline of the 14 casing) as to complete the diametral expansion of the 15 casing to the intended final diameter of the casing.
16 Thereby the secondary expansion tool 304 functions to 17 bring about the secondary expansion of the casing.
18 (This secondary expansion will normally be the final 19 expansion of the casing, but if further expansion of 20 the casing is necessary or desirable, the expansion 21 tool 300 can be driven through the casing again with 22 the rollers 116 of the secondary expansion tool set at 23 a greater radial distance from the longitudinal axis of 24 the tool 304, or a larger expansion tool cah be driven 25 through the casing). While the primary expansion tool 26 302 with its conical array of rollers 310 is preferred 27 for initial expansion of casing, the secondary 28 expansion tool 304 with its radially adjustable rollers 29 has the advantage that the final diameter to which the

30 casing is expanded can be selected within a range of

31 diameters. Moreover, this final diameter can not only

32 be adjusted while the tool 304 is static but=can also

33 be adjusted during operation of the tool by suitable

34 adjustment of the extent to which the interior of the 1 tool 304 is pressurised above the pressure around the 2 outside of the tool 304. This feature also gives the 3 necessary compliance to deal with variances in wall 4 thickness Fig. 25 is a longitudinal section of a primary 6 expansion tool 402 which is a modified version of the 7 primary expansion tool 302 (detailed above with 8 reference to Figs. 20 - 24) . Components of the tool 9 402 which correspond to components of the tool 302 are given the same reference numeral except that the 11 leading "3" is replaced by a leading "4". The tool 402 12 is essentially the same as the tool 302 except that the 13 rollers 410 are longer than the rollers 310, and the 14 conical race 412 has a cone angle which is less than the cone angle of the race 312 (i.e. the race 412 16 tapers less and is more nearly cylindrical than the 17 race 312). As shown in Fig. 25, the trailing (uphole) 18 end of the tool 402 is broken away. For details of 19 other parts of the tool 402, reference should be made to the foregoing description of the tool 302. In 21 contrast to Figs. 20 - 24, Fig. 25 also shows a 22 fragment of casing 480 which is undergoing expansion by 23 the tool 402.

24 Fig. 26 is a longitudinal section of a primary expansion tool 502 which is a further-modified version 26' of the primary expansion tool 302. Components of the 27 tool 502 which correspond to components of the tool 302 28 are given the same reference numeral except that the 29 leading 113" is replaced by a leading "5". The tool 502 is identical to the tool 402 except that the rollers 31 510 have a length which is somewhat less than the 32 length of the rollers 410. This reduced length allows 33 the rollers 510 some longitudinal freedom within their 1 windows in the cage 514. Consequently, although 2 expansion operation of the primary expansion tool 502 3 is essentially identical to operation of the primary 4 expansion tool 410 (and similar to operation of the primary expansion tool 310 except for functional 6 variations occasioned by the different conicities of 7 the respective races), reversal of longitudinal thrust 8 on the tool 502 (i.e. pulling the tool 502 uphole 9 instead of pushing the tool 502 downhole) will cause or allow the rollers 510 to slide along the conical race 11 512 in the direction of its reducing diameter, thus 12 allowing the rollers 510 radially to retract from the 13 casing bore as illustrated in Fig. 26. Such roller 14 retraction frees the tool 502 from the casing 480 and permits free withdrawal of the tool 502 in an uphole 16 direction whereas the non-retracting rollers 410 of the 17 tool 402 might possibly jam the tool 402 within the 18 casing 480 in the event of attempted withdrawal of the 19 tool 402.

Turning now to Fig. 27, this is a simplified 21 longitudinal elevation of a casing expander assembly 22 600 for use in downhole expansion of a solid, slotted 23 or imperforate metal tube 602 within a casing 604 which 24 lines a well.= The casing expander assembly 600 is a' three-stage expansion tool which is generally similar 26 (apart from the number of expansion stages) to the two-27 stage expansion tool 300 described above with reference 28 to Figs. 20 - 24.

29 In order from its leading (downhole) end, the expander assembly 600 comprises a running/guide assembly 610, a 31 first-stage conical expander 612, an inter-stage 32 cohpling 614, a second-stage conical expander 616, a 33 further inter-stage coupling 618, and a third-stage 1 cylindrical expander 620.

2 The first-stage conical expander 612 comprises a 3 conical array of tapered rollers which may be the same 4 as either one of the primary expansion tools 302 or 402, or which differs therefrom in respect of the 6 number of rollers and/or in respect of the cone angles 7 of the rollers and their race.

8 The second-stage conical expander 616 is an enlarged-9 diameter version of the first-stage conical expander 612 dimensioned to provide the intermediate expansion 11 stage of the three-stage expansion assembly 600. The 12 diameter of the leading (narrow) end of the second-13 stage expander 616 (the lower end of the expander 616 14 as viewed in Fig. 27) is marginally less than the diameter of the trailing (wide) end of the first-stage 16 expander 612 (the upper end of the expander 612 as 17 viewed in Fig. 27) such that the second-stage expander 18 616 is not precluded from entering initially expanded 19 tube 602 resulting from operation of the first-stage expander 612.

21 The third-stage expander 620 is a generally cylindrical 22 expander which may be similar either to the profiling 23 tool 100 or to the secondary expansion tool 304.
24 (Although the rollers of the third-stage expander 620 may be termed "cylindrical" in order to facilitate 26 distinction over the conical rollers of the first-stage 27 and second-stage expanders 612 & 616, and although in 28 certain circumstances such so-called "cylindrical"
29 rollers may in fact be truly cylindrical, the rollers of the cylindrical expander will usually be barrelled 31 tb avoid excessive end stresses). The rollers of the 32 third-stage expander 620 will normally be radially 1 extended from the body of the expander 620 by an extent 2 that the third-stage expander 620 rolls the tube 602 3 into its final extension against the inside of casing 4 604, such that no further expansion of the tube 602 is required in the short term.

6 The inter-stage couplings 614 and 618 can be 7 constituted by any suitable arrangement that 8 mechanically couples the three expander stages, and 9 (where necessary or desirable) also hydraulically couples the stages.

11 The rollers of the third-stage expander 620 may be 12 skewed such that rotation of the assembly 600 drives 13 the assembly in a downhole direction; alternatively, 14 the rollers may be unskewed and forward thrust on the expanders be provided by suitable weights, e.g. by 16 drill collars 630 immediately above the assembly 600.
17 Where the third-stage rollers are skewed, drill collars 18 can be employed to augment the downhole thrust provided 19 by rotation of the assembly 600.

As depicted in Fig. 27, the three-stage expander 21 assembly 600 is suspended from a drillstring 640 which 22 not only serves for transmitting totation to the 23 assembly 600 but also serves for transmitting hydraulic 24 fluid under pressure to the assembly 600 for radial extension of the third-stage rollers, for cooling the 26 assembly 600 and newly deformed tube 602, and for 27 flushing debris out of the work region.

28 In suitable circumstances, the drillstring 640 may be 29 substituted by coiled tubing (not shown) of a form known per se.

1 Turning now to Fig. 28 (which is divided into three 2 mutually related Figs. 28A, 28B, & 28C), these 3 illustrate a primary expansion tool 702 which may be 4 summarised as being the primary expansion tool 402 5 (Fig_ 25) with hard steel bearing balls 710 substituted 6 for the rollers 410. Each of the balls 710 runs in a 7 respective circumferential groove 712, and is located 8 for proper tracking by a suitably perforated cage 714.
9 As with the tool 402, the cage 714 is retained by a 10 retainer 716 secured on the screw-threaded leading end 11 718 of the tool 702 by means of a ring nut 720.
12 Operation of the tool 702 is functionally similar to 13 operation of the tool 402, as is illustrated by the 14 expansion effect of the tool 702 on casing 480.

15 The primary expansion tool 702 as shown in Figs. 28A -16 28C could be modified by the substitution of the series 17 of circumferential ball tracks 712 with a single spiral 18 track (not shown) around which the balls 710 would 19 circulate at ever-increasing radii to create the 20 requisite expansion forces on the casing. At the point 21 of maximum radius, the balls 710 would be recirculated 22 back to the point of minimum radius (near the leading 23 end of the tool 702, adjacent the retainer 716) by 24 means of a channel (not shown) formed entirely within 25 the central body of the tool 702 in a form analogous to 26 a recirculating ball-screw (known per se).

27 Figs. 29A & 29B illustrate a modification 802 of the 28 ball-type expansion primary expansion tool 702 of Fig.
29 28 analogous to the Fig. 26 modification 502 of the 30 Fig. 25 roller-type primary expansion tool 402. In the 31 modified ball-type primary expansion tool 802., the hard 32 steel bearing balls 810 run in longitudinally-extending 33 grooves 812 instead of the circumferential grooves 712 1 of the tool 702. The ball-guiding perforations in the 2 cage 814 are longitudinally extended into slots which 3 allow individual balls 810 to take up different 4 longitudinal positions (and hence different effective radii) according to whether the tool 802 is being 6 pushed downhole (Fig. 28A) or being pulled uphole (Fig.
7 28B). In the latter case, the balls 810 are relieved 8 from pressure on the surrounding casing 480 and thereby 9 obviate any risk of the tool 802 becoming jammed in partly-expanded casing.

11 In the profiling and expansion tools with controllably 12 displaceable rollers as previously described, e.g. with 13 reference to Figs. 4 and 24, the ability to obtain and 14 to utilise hydraulic pressure may place practical limits on the forces which can be exerted by the 16 rollers. Fig. 30 illustrates a roller-type 17 expansion/profiling tool 900 which utilises a 18 mechanical force-multiplying mechanism to magnify a 19 force initially produced by controlled hydraulic pressure, and to apply the magnified force to 21 profiling/expanding rollers 902. Each of the plurality 22 of rollers 902 (only two being visible in Fig. 30) has 23 a longitudinally central portion which is near-24 cylindrical and slightly barrelled (i.e.=slightly convex), bounded on either side by end portions which 26 are conical, both end portions tapering from 27 conjunction with the central portion to a minimum 28 diameter at each end. Rotation of each roller 902 29 about a respective rotation axis which is parallel to the longitudinal axis of the tool 900 and at a -31 controllably variable radial displacement therefrom is 32 ensured by a roller-guiding cage 904 of suitable form. .
.

33 The effective working diameter of the tool 900 is WO 00137766 PCTlGB99/04225 1 dependent on the (normally equal) radial displacements 2 of the rollers 902 from the longitudinal axis of the 3 tool 900 (such displacement being shown at a minimum in 4 Fig. 30). The conical end portions of each roller 902 each run on a respective one of two conical races 906 6 and 908 whose longitudinal separation determines the 7 radial displacement of the rollers 902. The conical 8 races 906 and 908 are coupled for synchronous rotation 9 but variable separation by means of a splined shaft 910 which is rigid with the upper race 906 and non-11 rotatably slidable in the lower race 908. The tool 900 12 has a hollow core which hydraulically couples through 13 an upper sub 912 to a drilistring (not shown) which 14 both selectively rotates the tool 900 within surrounding casing 990 which is to be profiled/expanded 16 by the tool 900 and transmits controllable hydraulic 17 pressure to the core of the tool 900 for controlling 18 the roller displacement as will now be detailed.

19 The lower end of the tool 900 (with which the lower race 908 is integral) is formed as hollow cylinder 914 21 within which a piston 916 is slidably sealed. The 22 piston 916 is mounted on the lower end of a downward 23 extension of the shaft 910 which is hollow to link 24 through the tool core and the drillstring to the controlled hydraulic pressure. The piston 916 divides 26 the cylinder 914 into upper and lower parts. The upper 27 part of the cylinder 914 is linked to the controlled 28 hydraulic pressure by way of a side port 918 in the 29 hollow shaft 910, just above the piston 916. The lower part of the cylinder 914 is vented to the outside of 31 the tool 900 through a hollow sub 920 which constitutes 32 the lower end of the tool 900 (and which enables 33 further components, tools, or drillstring (not shown)) 34 to be connected below the tool 900). Thereby a 1 controllable hydraulic pressure differential can be 2 selectively created across the piston 916, with 3 consequent control of the longitudinal separation of 4 the two roller-supporting conical races 906 and 908 which in turn controls the effective rolling diameter 6 of the tool 900.

7 While certain modifications and variations of the 8 invention have been described above, the invention is 9 not restricted thereto, and other modifications and variations can be adopted without departing from the 11 scope of the invention as defined in the appended 12 claims.

Claims (13)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A method of forming a seal between two tubular members, the method comprising:

providing a first tubular member having an internal surface and an external surface, the external surface describing a first diameter;

providing at least one recess in said external surface at a seal portion of the first tubular member, said seal portion having a wall thickness substantially equal to the wall thickness of the tubular member adjacent said seal portion;

locating a deformable sealing member in the recess such that the sealing member describes an external diameter no greater than said first diameter;

locating the first tubular member within a second tubular member; and expanding at least the seal portion of the first tubular member such that the sealing member engages an inner surface of the second tubular member.

2. The method of claim 1, wherein the seal portion is expanded by rolling expansion, with an expansion member being rotated within the first tubular member with a face in rolling contact with an internal surface thereof.

3. The method of claim 1 or 2, wherein the first tubular member is expanded only at or in the region of the seal portion.

4. A seal-forming arrangement comprising:

a first tubular member having an internal surface, and an external surface describing a first diameter, the tubular member defining at least one recess in said external surface at a deformable seal portion of the first tubular member, said seal portion having a wall thickness substantially equal to the wall thickness of the tubular member adjacent said seal portion; and a deformable sealing member in the recess, the sealing member describing an external diameter no greater than said first diameter;
wherein expansion of at least the seal portion of the first tubular member increases the diameter of the sealing member to at least said first diameter.

5. The arrangement of claim 4, wherein the sealing member is of an elastomer.

6. The arrangement of claim 4, wherein the sealing member is of a ductile metal.

7. A method of sealing an annular area in a wellbore, the method comprising:
providing a tubular member; and mechanically deforming the tubular member in a manner whereby an outer surface of the tubular member assumes a shape of a non-uniform surrounding surface and forms a seal therebetween.

8. The method of claim 7, wherein deforming the tubular member includes applying a compliant roller system to an inner surface of the tubular member.

9. The method of claim 7 or 8, wherein deforming the tubular member includes expanding the tubular member with an expander tool having at least two radially extendable members.

10. The method of claim 9, wherein the expander tool is hydraulically actuated.

11. The method of claim 9 or 10, wherein the at least two radially extendable members are fluid-pressure actuated.

12. The method of claim 10 or 11, wherein the expander tool comprises an annular body having a longitudinal bore disposed therethrough, and wherein the at least two radially extendable members are mounted on slidable pistons, each piston having a piston surface on the underside thereof.

13. The method of claim 12, wherein the radially extendable members are extended via the fluid pressure on the piston surfaces, and wherein increased fluid pressure results in an increased extension of the radially extendable members.