GB2526354A

GB2526354A - Improved isolation barrier

Info

Publication number: GB2526354A
Application number: GB1409170.6A
Authority: GB
Inventors: Scott James Mcbride
Original assignee: Meta Downhole Ltd
Current assignee: Meta Downhole Ltd
Priority date: 2014-05-22
Filing date: 2014-05-22
Publication date: 2015-11-25
Also published as: WO2015177545A3; GB201409170D0; WO2015177545A2; US20150337617A1; US20150337616A1

Abstract

An assembly 10 comprising a tubular body 12 arranged to be run in and secured within a larger diameter, generally cylindrical structure, a sleeve member 14 positioned on the exterior of the tubular body, creating a chamber 16 therebetween, the tubular body including a port 18 permitting flow of fluid into the chamber to cause the sleeve member to move outwardly against an inner surface of the larger diameter, characterised in that at least one torsion spring is located within the chamber, the torsion spring 20 relaxing as the sleeve member is moved outwardly by fluid pressure to provide a frame within the chamber when the sleeve member is pressed against the inner surface of the larger diameter structure.

Description

IMPROVED ISOLATION BARRIER

The present invention relates to an apparatus and method for securing a tubular within another tubular or borehole, creating a seal across an s annulus in a well bore, and centralising or anchoring tubing within a wellbore. In particular, though not exclusively, the invention relates to morphing a sleeve to secure it to a well bore wall by the use of fluid pressure and providing a torsion spring to support of the sleeve in the event of collapse so as to maintain a seal between the sleeve and well ao bore wall.

In the exploration and production of oil and gas wells, packers are typically used to isolate one section of a downhole annulus from another section of the downhole annulus. The annulus may be between tubular members, such as a liner, mandrel, production tubing and casing or between a tubular member, typically casing, and the wall of an open borehole. These packers are carried into the well on tubing and at the desired location, elastomeric seals are urged radially outwards or elastomeric bladders are inflated to cross the annulus and create a seal with the outer generally cylindrical structure i.e. another tubular member or the borehole wall. These elastomers have disadvantages, particularly when chemical injection techniques are used.

As a result, metal seals have been developed, where a tubular metal member is run in the well and at the desired location, an expander tool is run through the member. The expander tool typically has a forward cone with a body whose diameter is sized to the generally cylindrical structure so that the metal member is expanded to contact and seal against the cylindrical structure. These so-called expanded sleeves have an internal surface which, when expanded, is cylindrical and matches the profile of the expander tool. These sleeves work well in creating an annular seal between tubular members but can have problems in sealing against the irregular surface of an open borehole.

The present applicants have developed a technology where a metal sleeve s is forced radially outwardly by the use of fluid pressure acting directly on the sleeve. Sufficient hydraulic fluid pressure is applied to move the sleeve radially outwards and cause the sleeve to morph itself onto the generally cylindrical structure. The sleeve undergoes plastic deformation and, if morphed to a generally cylindrical metal structure, the metal ao structure will undergo elastic deformation to expand by a small percentage as contact is made. When the pressure is released the metal structure returns to its original dimensions and will create a seal against the plastically deformed sleeve. During the morphing process, both the inner and outer surfaces of the sleeve will take up the shape of the surface of the wall of the cylindrical structure. This morphed isolation barrier is therefore ideally suited for creating a seal against an irregular borehole wall.

Such a morphed isolation barrier is disclosed in US 7,306,033, which is zo incorporated herein by reference. An application of the morphed isolation barrier for FRAC operations is disclosed in US2012/0125619, which is incorporated herein by reference. Typically, the sleeve is mounted around a supporting tubular body, being sealed at each end of the sleeve to create a chamber between the inner surface of the sleeve and the outer surface of the body. A port is arranged through the body so that fluid can be pumped into the chamber from the throughbore of the body.

U52007/0089886 to Schlumberger Technology Corporation discloses an expandable sleeve for use in a well, comprising a tubular structure including an external sealing layer comprising a compliant material; an intermediate expandable tubular body made from a plastically deformable material; and an internal spring structure such as a helically wound spring; wherein the external sealing layer is disposed on the outer surface of the tubular body, and the internal spring structure is disposed inside the tubular body and acts so as to exert a radial force on the body when in an expanded state. The sleeve is expanded by running a cone through s the tubular. In use, the spring must be held in compression when the tubular structure is run-in a well bore and released when the radial support is required following expansion. Alternatively, the tubular body is located in the well bore and expanded prior to the spring being run-in and inserted in the expanded to body to provide radial support. A ao disadvantage of this arrangement is that each of the processes requires a second trip into the well bore to release the spring or locate the spring in position.

GB2417271 to Schlumberger Holdings Limited describes an energised sealing element for a packer that maintains a seal under various conditions by providing a source of stored energy that can be used to insure that contact forces are maintained between the seal and the wall or casing of the wellbore. Various combinations of sealing layers, support sleeves and energising elements are disclosed. The seal layer may be zo made from rubber, an elastomeric compound, metal, thermoplastic or other soft, deformable materials. The support sleeve and energizing element may be made of metal, composite materials or various other materials that would permit the storage of mechanical potential energy.

The energising element may take the form of a bow and wedges, a spring, a bag or container which is energised with gas or other compressible material or a swelling material. For the spring arrangement, a coil type spring is described held in place by a pin or weld. Such an arrangement requires a mechanism to release the spring when the packer is in the desired position. For the bow arrangement, wedges are moved radially inside the bow to force the bow radially outwards to contact and move the support sleeve. Again a mechanism is required to move wedges inside the bow when the packer is to be expanded. Such additional mechanisms may fail, thus preventing expansion of the packer.

A further disadvantage of the prior art spring arrangements is that the s spring is left exposed within the throughbore of the barrier/packer/sleeve following expansion. This provides multiple points for the build-up of debris or for later run tools to catch and stick upon.

It is therefore an object of at least one embodiment of the present ao invention to provide a morphed isolation barrier which obviates or mitigates one or more disadvantages of the prior art.

It is a further object of at least one embodiment of the present invention to provide a method of creating an isolation barrier in a well bore which obviates or mitigates one or more disadvantages of the prior art.

According to a first aspect of the present invention there is provided an assembly, comprising: a tubular body arranged to be run in and secured within a larger diameter zo generally cylindrical structure; a sleeve member positioned on the exterior of the tubular body, to create a chamber therebetween; the tubular body including a port to permit the flow of fluid into the chamber to cause the sleeve member to move outwardly and morph against an inner surface of the larger diameter structure; and characterised in that: at least one torsion spring is located within the chamber; the torsion spring relaxing as the sleeve member is moved outwardly by fluid pressure to provide a frame within the chamber when the sleeve member is morphed against the inner surface of the larger diameter structure.

In this way, the torsion spring is always contained within a chamber and is advantageously activated by the fluid pressure used to morph the sleeve member. Thus a second run in the well-bore is not required to position/operate the spring and the spring is not left exposed in the s throughbore. The relaxed torsion spring creates a frame to support the sleeve member and assist in preventing collapse, once the sleeve has been morphed by fluid pressure.

Preferably, the torsion spring is a helically coiled spring which unwinds as it relaxes. In this way, the torsion spring can be helically wound around the tubular body to ease construction.

Preferably, the torsion spring has a relaxed diameter less than the diameter of the larger diameter structure. More preferably, the torsion spring has a relaxed diameter less than the diameter of the morphed sleeve. In this way, the torsion spring provides a frame with a diameter less than the diameter of the larger diameter structure and, preferably, less than the diameter of the morphed sleeve. Also, the torsion spring does not exert a radial force on the morphed sleeve. This is in contrast to zo the prior art spring arrangements and advantageously prevents rupture of the sleeve when it is thinned during expansion.

Preferably, the torsion spring has a square or rectangular cross-section.

In this way, the torsion spring presents a flat, smooth surface to contact the inner surface of the sleeve member. This limits damage or puncturing of the sleeve member as it is thinned during morphing.

The sleeve member may have a first end which is affixed and sealed to the tubular body and a second end which includes a sliding seal to permit longitudinal movement of the second end over the tubular body. In this way, as the sleeve is morphed, longitudinal contraction of the sleeve member occurs which reduces the thinning of the sleeve member during morph in g.

The large diameter structure may be an open hole borehole, a borehole s lined with a casing or liner string which may be cemented in place downhole, or may be a pipeline within which another smaller diameter tubular section requires to be secured or centralised.

The tubular body is preferably located coaxially within the sleeve and is ao part of a tubular string used within a wellbore, run into an open or cased oil, gas or water well. Therefore the present invention allows a casing section or liner to be centralised within a borehole or another downhole underground or above ground pipe by provision of a morphable sleeve member positioned around the casing or liner. Centralisation occurs as the sleeve will expand radially outwardly at a uniform rate with the application of pressure from the fluid. Additionally, the present invention can be used to isolate one section of the downhole annulus from another section of the downhole annulus and thus can also be used to isolate one or more sections of downhole annulus from the production conduit.

Preferably, there is a plurality of ports arranged through the tubular body.

In this way, rapid morphing of the sleeve member can be achieved. The ports may be arranged circumferentially around the body. The ports may be arranged longitudinally along the body. As the torsion spring is coiled helically around the tubular body, space may be left between each adjacent coil so that fluid can bypass the springs at all times to act against the sleeve member. This is in contrast to the prior art arrangements of a tube in which slots are cut longitudinally or helically on the tube body. Fluid flow through the wall of the tube is restricted until sufficient longitudinal compression of the tube has occurred to move the strips, between the slots, radially outwards.

The port may include a barrier. In this way, fluid is prevented from entering the chamber until activation is required. The barrier may be a rupture disc which allows fluid to flow through the port at a predetermined fluid pressure. Alternatively the barrier may be a valve.

s Preferably the valve is a one-way check valve. In this way, fluid is prevented from exiting the chamber. More preferably the valve is set to close when the pressure in the chamber reaches a morphed pressure value. In this way, the torsion spring can assist in morphing the sleeve by exerting a radial force on the sleeve member during morphing, but will ao not exert any pressure at the time the seal is made between the sleeve member and the larger diameter structure.

According to a second aspect of the present invention there is provided a method of setting a morphed sleeve in a well bore, comprising the steps: (a) locating a sleeve member on the exterior of a tubular body and sealing it thereto to create a chamber therebetween, (b) locating a torsion spring in the chamber; (c) running the tubular body on a tubular member into a wellbore and positioning the sleeve member at a desired location within a larger zo diameter structure; (d) pumping fluid through the tubular member and through a port in the tubular body to access the chamber; (e) causing the sleeve member to move radially outwardly and morph against an inner surface of the larger diameter structure; (f) allowing the torsion spring to relax and exert a radial force on the sleeve member as the sleeve member is moved radially outwardly towards the inner surface of the larger diameter structure; and (g) creating a frame from the relaxed torsion spring to prevent collapse of the morphed sleeve member.

In this way, the naturally occurring unwinding of the torsion spring during morphing is used to assist in expanding the sleeve member and once relaxed, the torsion spring acts as a frame to support the morphed sleeve and prevent collapse thereof. Thus the creation of the barrier and the frame, formed from the relaxed spring, can be achieved in a single run in the well bore.

Preferably, the method includes the step of selecting a torsion spring having a relaxed diameter less than a diameter of the larger diameter structure. More preferably, the method includes the step of selecting a torsion spring having a relaxed diameter less than a calculated diameter ao of the morphed sleeve.

The large diameter structure may be an open hole borehole, a borehole lined with a casing or liner string which may be cemented in place downhole, or may be a pipeline within which another smaller diameter tubular section requires to be secured or centralised.

Preferably, step (d) includes the step of pumping fluid through the tubular member and through multiple ports in the tubular body to access the chamber. This provides a faster morphing of the sleeve.

Preferably, the method includes the step of rupturing a disc at a valve in the port to allow fluid to enter the chamber when the pressure reaches a desired value. This allows selective and controlled activation of the morphing process.

The method may include the steps of running in an activation fluid delivery tool, creating a temporary seal above and below the port and injecting fluid from the tool into the chamber via the port. Such an arrangement allows selective operation of the sleeve member if more than one sleeve member is arranged in the well bore.

In the description that follows, the drawings are not necessarily to scale.

Certain features of the invention may be shown exaggerated in scale or in somewhat schematic form, and some details of conventional elements may not be shown in the interest of clarity and conciseness. It is to be fully recognized that the different teachings of the embodiments discussed below may be employed separately or in any suitable combination to produce the desired results.

Accordingly, the drawings and descriptions are to be regarded as ao illustrative in nature, and not as restrictive. Furthermore, the terminology and phraseology used herein is solely used for descriptive purposes and should not be construed as limiting in scope. Language such as "including," "comprising," "having," "containing," or "involving," and variations thereof, is intended to be broad and encompass the subject matter listed thereafter, equivalents, and additional subject matter not recited, and is not intended to exclude other additives, components, integers or steps. Likewise, the term "comprising" is considered synonymous with the terms "including" or "containing" for applicable legal purposes.

All numerical values in this disclosure are understood as being modified by "about". All singular forms of elements, or any other components described herein including (without limitations) components of the apparatus are understood to include plural forms thereof.

An embodiment of the present invention will now be described, by way of example only, with reference to the accompanying drawings of which: Figure 1 is a cross-sectional view through an assembly according to an embodiment of the present invention; Figure 2 is a cross-sectional view through the assembly of Figure 1 following morphing of the sleeve member; and Figure 3 is a schematic illustration of a sequence for setting two sleeve s members in an open borehole; FIG. 3a is a cross-sectional view of a liner provided with two sleeve members; FIG. 3b shows the liner in the borehole of FIG. 3a with an activation fluid delivery tool inserted therein; and FIG. 3c is a cross-sectional view of the liner of FIGS. 3a and 3b with morphed sleeves and a relaxed torsion spring, in use.

Reference is initially made to Figure 1 of the drawings which illustrates an assembly, generally indicated by reference numeral 10, including a tubular body 12, sleeve member 14, chamber 16, port 18 and torsion spring, generally indicated by reference numeral 20, according to an embodiment of the present invention.

Tubular body 12 is a cylindrical tubular section having at a first end 22, a first connector (not shown) and at an opposite end 26, a second connector (not shown) for connecting the body 12 into a tubing string zo such as casing, liner or production tubing that is intended to be permanently set or completed in a well bore. Body 12 includes a throughbore 30 which is co-linear with the throughbore of the string. The string may be a drill pipe or any other tubular string designed to be run in a well bore.

A port 18 is provided through the side wall 34 of the body 12 to provide a fluid passageway between the throughbore 30 and the outer surface 36 of the body 12. While only a single port 18 is shown, it will be appreciated that a set of ports may be provided. These ports may be equidistantly spaced around the circumference of the body 12 and/or be arranged along the body between the first end 22 and the second end 26 to access the chamber 16. :ii

In an embodiment, at the port 18 there is located a check valve 54. The check valve 54 is a one-way valve which only permits fluid to pass from the throughbore 30 into the chamber 16. The check valve 54 can be s made to close when the pressure within the chamber 16 reaches a predetermined level, this being defined as the morphed pressure value.

Thus, when the pressure in the sleeve 14 reaches the morphed pressure value, the valve 54 will close. Also arranged at the port 18 is a rupture disc 56. The rupture disc 56 is rated to a desired pressure at which fluid ao access to the chamber is desired. In this way, the rupture disc 56 can be used to control when the setting of the sleeve 14 is to begin. The disc 56 can be operated by increasing pressure in the throughbore 30 with the pressure to rupture the disc being selected to be greater than the fluid pressure required to activate any other tools or functions in the well bore.

Tubular body 12 is located coaxially within a sleeve member 14. Sleeve member 14 is a steel cylinder being formed from typically 316L or Alloy 28 grade steel but could be any other suitable grade of steel or any other metal material or any other suitable material which undergoes elastic and zo plastic deformation. Ideally the material exhibits high ductility i.e. high strain before failure. The sleeve member 14 is appreciably thin-walled of lower gauge than the tubing body 12 and is preferably formed from a softer and/or more ductile material than that used for the tool body 12.

The sleeve member 14 may be provided with a non-uniform outer surface 40 such as ribbed, grooved or other keyed surface in order to increase the effectiveness of the seal created by the sleeve member 14 when secured within another casing section or borehole.

An elastomer or other deformable material may be bonded to the outer surface 40 of the sleeve 14; this may be as a single coating but is preferably a multiple of bands with gaps therebetween. The bands or coating may have a profile or profiles machined into them. The elastomer bands may be spaced such that when the sleeve 14 is being morphed the bands will contact the inside surface 24 of the larger diameter structure (casing 28 or open borehole 80) first. The sleeve member 14 will continue to expand outwards into the spaces between the bands, thereby causing a s corrugated effect on the sleeve member 14. These corrugations provide a great advantage in that they increase the stiffness of the sleeve member 14, increase its resistance to collapse forces and also improves annular sealing.

ao Sleeve member 14 which surrounds the tubular body 12 is affixed thereto via welded or clamped connections 42, 44, respectively. Such attachments 42, 44 are pressure-tight connectors. An 0-ring seal (not shown) may also be provided between the inner surface 46 of the sleeve member 14 and the outer surface 36 of the tubular body 12 to act as a secondary seal or back-up to the seal provided by the welded connections. In an embodiment of the present invention, the first attachment means 42 is provided by a mechanical clamp to fix the first end 48 of sleeve member 14 to the tubular body 12. The second end 50 of the sleeve member 14 is connected to the outer surface 36 of the zo tubular body 12 via a sliding seal arrangement. In this way, the second end 50 of the sleeve member 14 can move longitudinally along the outer surface 36 of the tubular body 12 while maintaining a seal between the surfaces to hold pressure within the chamber 16. This sliding seal is arranged so that the second end 50 of the sleeve member 14 is permitted to move towards the first end 48. Thus when the sleeve member 14 is caused to move in a radially outward direction, during morphing, the sleeve contracts which causes simultaneous movement of the sliding seal.

This has the advantage in reducing thinning of the material of the sleeve 14 by the radial outward expansion.

The attachments 42, 44 together with the inner surface 46 of the sleeve member 14 and the outward surface 36 of the body 12 define the chamber 16. The port 18 is arranged to access the chamber 16 and permit fluid communication between the through-bore 30 and the chamber 16.

s Located within the chamber 16, is a torsion spring 20. Torsion spring 20 comprises a helically wound wire. Torsion spring 20, as shown in the embodiment in Figure 1, has a circular cross-section 52 but may preferably have a square or rectangular cross-section so as to provide a smooth contact between the outer surface 58 of the spring 20 and the ao inner surface 46 of the sleeve 14.

Torsion spring 20 is as known in the art of helically wound coiled spring design in which energy is stored within the spring 20 by being tightly wound and held in compression. In the embodiment shown in Figure 1, torsion spring 20 is in compression. Naturally, the torsion spring 20 wishes to relax and in doing so, will wish to unwind and thus provide a radially outward force from the body 12 against the inner surface 46 of the sleeve member 14. Thus, once constructed, the assembly 10 will have the torsion spring 20 held in compression within the chamber 16. In zo the embodiment shown, there is a single torsion spring 20 extending from a first end 48 of the sleeve member to a second end 50 of the sleeve member along the entire length of the chamber 16. Alternatively, there may be a number of separate torsion springs arranged along the length of the chamber 16. In this arrangement, the centre-most torsion spring may have a higher compressibility factor so that it exerts a stronger radial force against the inner surface 46 of the sleeve member 14 thus causing expansion at the centre point of the sleeve member 14 ahead of the outer ends 48, 50 of the sleeve member. This will assist in preventing hydraulic lock during morphing of the sleeve member 14.

The torsion spring may be held against the outer surface 36 of the tubular body 12, held against the inner surface 46 of the sleeve member 14 or preferably let free within the chamber 16 and not be directly attached to any part thereof.

Thus, the assembly 10 is constructed by taking a tubular body 12 and s locating a sleeve member 14 thereon. A first end 48 of the sleeve member 14 is attached to the tubular body via the attachment 42. The torsion spring 20 is then compressed under tension by tightening the spring to reduce its diameter so that it fits within the inner diameter of the sleeve member 14. Once located in the sleeve, the second end 50 of ao the sleeve member is also attached to the tubular body, via attachment 44. The diameter of the sleeve member 14 will have been selected to match the inner diameter of the casing 28 into which the assembly 10 is intended for use. Likewise, the torsion spring 20 will have been selected so that its relaxed diameter i.e. the diameter in which the spring takes up when entirely unwound and unbounded is selected to be less than the inner diameter of the casing 28 and preferably of a diameter less than the intended diameter for the morphed sleeve 14. This will be described hereinafter with reference to the morphed sleeve. Assembly 10 is then connected into a string as is known in the art and run into the wellbore 60. The assembly 10 is run into a position where a barrier is required and in the embodiment shown in Figure 1, this is inside casing 28. As casing 28 comes in standard sizes of diameters then the assembly 10 of the present invention can also be formed in standard sizes selected for the diameter of the casing in which it will form a barrier.

When the assembly 10 is in position in the casing 28, pressure in the through-bore 30 is increased. This is typically fluid pressure delivered from a pump at surface with a plug or stop located within the through-bore 30 at a position below the assembly 10 in the string. Pressure in the through-bore 30 thus increases to a point where the disc 56 ruptures and allows fluid under pressure to pass through the check valve 54 at the port 18. As detailed previously, multiple ports 18 may be located upon the tubular body 12 to increase the rate of fluid pressure entering the chamber 16. The torsion spring 20 is preferentially wound to provide a spacing between the individual coils of the helix so that as the fluid enters chamber 16, it will pass through the torsion spring 20 unimpeded and act s against the inner surface 46 of the sleeve member 14. As the chamber 16 is cylindrical in nature and the material of the sleeve member 14 is more elastic than that of the tubular body 12, as pressure increases in the chamber 16, the sleeve member 14 will be forced radially outwardly from the tubular body across the annulus 62 between the outer surface 36 of the tubular body 12 and the inner surface 24 of the casing 28. This expansion of the sleeve member 14 by fluid pressure is assisted by the torsion spring 20 also expanding as it unwinds in the greater space being made available as the chamber 16 increases in volume. During unwinding of the torsion spring 20, the spring 20 will exert a radial force on the inner surface 46 of the sleeve member 14.

Fluid pressure will continue to enter through port 18 until the sleeve member 14 contacts the inner surface 24 of the casing 28 and effectively morphs the material of the sleeve member 14 against the inner surface 24. This morphing creates a metal-to-metal seal between the sleeve member 14 and the casing 28. This process is known and operates by elastically and then plastically deforming the sleeve member 14. On contact with the casing 28, the casing 28 may also elastically deform under fluid pressure. At a morphed fluid pressure value, the check valve 54 closes therefore sealing the chamber 16. At this pressure value, the sealed chamber and in particular, the sleeve member 14 will wish to relax slightly. This relaxation will cause the elastically deformed casing 28 to also contract back to its original diameter. This movement improves the metal-to-metal seal between the sleeve 14 and the casing 28. The seal between the assembly 10 and the casing 28 thus forms a barrier in the wellbore 60 so that fluid flow through the annulus 62 is prevented.

Indeed, a loss of fluid flow through the annulus 62 can be considered as the point at which an effective barrier seal has been made by the assembly 10.

During morphing of the sleeve member 14, the torsion spring 20 has s unwound to a relaxed position as shown in Figure 2. The spring 20 has now increased in diameter and is located just within the inner surface 46 of the sleeve 14. It may contact the sleeve 14 but the torsion spring 20 is designed such that it provides no radial force against the inner wall 46 of the sleeve 14 when in the relaxed position. The torsion spring 20 thus ao merely acts as a metal frame located within the chamber 16. During the morphing process, the second end 50 of the sleeve member 14 will have moved towards the first end 48 of the sleeve member 14 due to the longitudinal contraction of the sleeve member during radial expansion.

The spring 20 may also have reduced in length within the chamber 16.

The helical arrangement of the torsion spring 20 can reduce in length without affecting the diameter it takes up within the chamber 16.

The frame created by the torsion spring 20 in its relaxed position provides a support to the sleeve member 14 in the event that there is any zo potential collapse to the sleeve member 14. In such morphed sleeve arrangements, collapse can occur from a difference in the differential pressure between the pressure in chamber 16 and that in the annulus 62 above or below the assembly 10. Essentially, once morphed, the spring is there to prevent the morphed sleeve 14 from changing shape and getting to its first buckling mode (essentially going from a round to a heart shape). By preventing such a change in shape occurring, the barrier will retain its sealing ability against the casing 28. Thus, by incorporating a torsion spring 20 into the design, this allows for lower morph pressures to be used and accommodate a larger pressure differential across the barrier.

Reference will now be made to Figure 3 of the drawings which provides an illustration of a further method for setting a sleeve within a well bore according to an embodiment of the present invention. Like parts to those in the earlier Figures have been given the same reference numerals to aid s clarity.

In use, the assembly 10 is conveyed into the borehole by any suitable means, such as incorporating the assembly 10 into a casing or liner string 76 or on an end of a drill pipe and running the string into the wellbore 78 until it reaches the location within the open borehole 80 at which operation of the assembly 10 is intended. This location is normally within the borehole at a position where the sleeve 14 is to be expanded in order to, for example, isolate the section of borehole 80b located above the sleeve 14 from that below SOd in order to provide an isolation barrier between the zones 80b,80d. Additionally a further assembly lOb can be run on the same string 76 so that zonal isolation can be performed in a zone 80b in order that an injection, frac'ing or stimulation operation can be performed on the formation 80b located between the two sleeves 14, 14a. This is as illustrated in FIG. 3B.

Each sleeve 14,14a can be set by increasing the pump pressure in the throughbore 30 to a predetermined value which ruptures the disc 56 giving fluid access to the chamber 16. Fluid entering the chamber 16 increases in internal volume of the chamber 16, creating a pressure on the inner wall 46 sufficient to cause the sleeve 14 to move radially away from the body 12 by elastic expansion, contact the surface 82 of the borehole and morph to the surface 82 by plastic deformation.

Fluid may be pumped into the chamber 16 at any desired pressure as the the check valve 54 can be set to allow a calculated volume of fluid which is sufficient to morph the sleeve to enter the chamber before closing.

When closed, the check-valve will trap any fluid remaining in the chamber 16.

Additionally, by locating a plug at any desired position in the string, such s as the bottom of the string, fluid can be pumped from surface or from a tool located in the string to morph any desired number of sleeves, between the surface/tool and the plug, at the same time.

On run-in the torsion spring 20 is in a compressed state being held in tension. As the sleeve 14 is moved radially outwards, the second end 50 of the sleeve 14 will move towards the first end 42 of the sleeve 14. The sliding seal maintains contact on the liner 76 to ensure the chamber 16 remains sealed. Movement of the sleeve 14 radially outwardly expands the volume of the chamber and hence the torsion spring 20. As the torsion spring 20 unwinds it will exert a radial force upon the sleeve 14 and support the expansion of the sleeve. Note that this movement of the torsion spring 20 does not require separate intervention and occurs automatically on radial movement of the sleeve 14 due to morphing of the sleeve 14.

The sleeve 14 will have taken up a fixed shape under plastic deformation with an inner surface 46 matching the profile of the surface 82 of the borehole 80, and an outer surface also matching the profile of the surface 82 to provide a seal which effectively isolates the annulus 84 of the borehole 80 above the sleeve 14 from the annulus 86 below the sleeve 14. If two sleeves 14,14a are set together then zonal isolation can be achieved for the annulus 84 between the sleeves 14,14a. At the same time the sleeves 14,14a have effectively centered, secured and anchored the tubing string 76 to the borehole 80. When the sleeves 14,14a are morphed, the respective torsion springs 20 will have entirely unwound to their relaxed state creating a frame within the sleeves 14,14a. The torsion springs 20 do not exert any radial force on the morphed sleeves 14,14a and support to the sleeves 14,14a against collapse in the morphed configuration.

An alternative method of achieving morphing of the sleeve 14 is shown in S FIG 3B. This method uses an activation fluid delivery tool 88. Once the string 76 reaches its intended location, tool 88 can be run into the string 76 from surface by means of a coiled tubing 90 or other suitable method.

The tool 88 is provided with upper and lower seal means 92, which are operable to radially expand to seal against the inner surface 94 of the ao body 12 at a pair of spaced apart locations in order to isolate an internal portion of body 12 located between the seals 92; it should be noted that said isolated portion includes the fluid port 18. Tool 88 is also provided with an aperture 96 in fluid communication with the interior of the string 76.

To operate the tool 88, seal means 92 are actuated from the surface to isolate the portion of the tool body 12. Activation fluid is then pumped under pressure through the coiled tubing such that the pressurised fluid flows through tool aperture 96 and then via port 18 into chamber 16 and zo acts on the sleeve members 14,14b in the same manner as described hereinbefore. Use of such a tool allows setting of selective assemblies 10 in a well bore.

A detailed description of the operation of such a fluid delivery tool 88 is described in GB2398312 in relation to the packer tool 112 shown in Figure. 27 with suitable modifications thereto, where the seal means 92 could be provided by suitably modified seal assemblies 214, 215 of GB2398312, the disclosure of which is incorporated herein by reference.

The entire disclosure of GB2398312 is incorporated herein by reference.

Using either pumping method, the increase in pressure of fluid causes the sleeve 14 to move radially outwardly and seal against a portion of the inner circumference of the borehole 80 and the torsion spring 20 to relax and form a frame to support the sleeve 14 in the event of collapse in the morphed position. The pressure within the chamber 16 continues to increase such that the sleeve 14 initially experiences elastic expansion s followed by plastic deformation. The sleeve 14 expands radially outwardly beyond its yield point, undergoing plastic deformation until the sleeve 14 morphs against the surface 82 of the borehole 80 as shown in FIG.3C.

Accordingly, the sleeve 14 has been plastically deformed and morphed by pressure from the chamber contents without any mechanical expansion ao means being required. Note that the springs 20 support the sleeve during morphing of the sleeve but do not provide any support once morphing is complete unless a pressure differential is created across the sleeve 14 which would wish to cause the sleeve 14 to collapse. The spring 20 then acts as a support frame to prevent collapse of the sleeve 14 and maintain the seal.

The principle advantage of the present invention is that it provides an assembly for creating an isolation barrier in a well bore in which a torsion spring is used to create a supporting frame for the morphed sleeve in the zo event of collapsing of the sleeve.

A further advantage of the present invention is that it provides a method for setting a sleeve in a well bore in which support of the sleeve is achieved without additional intervention by using movement of the sleeve during the morphing process to provide for expansion of the spring.

It will be apparent to those skilled in the art that modifications may be made to the invention herein described without departing from the scope thereof. For example, while a single torsion spring is described, multiple torsion springs may be used to create the frame.

Claims

CLAIMS1. An assembly, comprising: a tubular body arranged to be run in and secured within a larger s diameter generally cylindrical structure; a sleeve member positioned on the exterior of the tubular body, to create a chamber therebetween; the tubular body including a port to permit the flow of fluid into the chamber to cause the sleeve member to move outwardly and morph ao against an inner surface of the larger diameter structure; and characterised in that: at least one torsion spring is located within the chamber; the torsion spring relaxing as the sleeve member is moved outwardly by fluid pressure to provide a frame within the chamber when the sleeve member is morphed against the inner surface of the larger diameter structure.
2. An assembly according to claim 1 wherein, the torsion spring is a helically coiled spring which unwinds as it relaxes.
3. An assembly according to claim 1 or claim 2 wherein, the torsion spring has a relaxed diameter less than a diameter of the larger diameter structure.
4. An assembly according to claim 3 wherein, the torsion spring has a relaxed diameter less than a diameter of the morphed sleeve.
5. An assembly according to any preceding claim wherein, the torsion spring has a rectangular cross-section.
6. An assembly according to any preceding claim wherein, the torsion spring has a square cross-section.
7. An assembly according to any preceding claim wherein, the sleeve member has a first end which is affixed and sealed to the tubular body and a second end which includes a sliding seal to permit longitudinal s movement of the second end over the tubular body.
8. An assembly according to any preceding claim wherein the large diameter structure is selected from a group comprising: an open hole borehole, a borehole lined with a casing or liner string, a borehole lined with a casing or liner string which is cemented in place downhole; a pipeline within which another smaller diameter tubular section requires to be secured or a pipeline within which another smaller diameter tubular section requires to be centralised.
9. An assembly according to any preceding claim wherein the tubular body is located coaxially within the sleeve and is part of a tubular string used within a wellbore.
10. An assembly according to any preceding claim wherein there is a zo plurality of ports arranged through the tubular body.
11. An assembly according to claim 10 wherein the ports are arranged circumferentially around the body.
12. An assembly according to claim 10 or claim 11 wherein the ports are arranged longitudinally along the body.
13. An assembly according to any preceding claim wherein the port includes a barrier.
14. An assembly according to claim 13 wherein the barrier is a rupture disc which allows fluid to flow through the port at a predetermined fluid pressure.
15. An assembly according to claim 13 or claim 14 wherein the barrier includes a valve.
16. An assembly according to claim 15 wherein the valve is a one-way check valve.
17. An assembly according to claim 15 or claim 16 wherein the valve is set to close when the pressure in the chamber reaches a morphed pressure value.
18. A method of setting a morphed sleeve in a well bore, comprising the steps: (a) locating a sleeve member on the exterior of a tubular body and sealing it thereto to create a chamber therebetween, (b) locating a torsion spring in the chamber; (c) running the tubular body on a tubular member into a wellbore and positioning the sleeve member at a desired location within a larger diameter structure; (d) pumping fluid through the tubular member and through a port in the tubular body to access the chamber; (e) causing the sleeve member to move radially outwardly and morph against an inner surface of the larger diameter structure; (f) allowing the torsion spring to relax and exert a radial force on the sleeve member as the sleeve member is moved radially outwardly towards the inner surface of the larger diameter structure; and (g) creating a frame from the relaxed torsion spring to prevent collapse of the morphed sleeve member.
19. A method of setting a morphed sleeve in a well bore according to claim 18 wherein, the method includes the step of selecting a torsion spring having a relaxed diameter less than a diameter of the larger diameter s structure.
20. A method of setting a morphed sleeve in a well bore according to claim 18 or claim 19 wherein, the method includes the step of selecting a torsion spring having a relaxed diameter less than a calculated ao diameter of the morphed sleeve.
21. A method of setting a morphed sleeve in a well bore according to any one of claims 18 to 20 wherein the large diameter structure is selected from a group comprising: an open hole borehole, a borehole lined with a casing or liner string, a borehole lined with a casing or liner string which is cemented in place downhole, a pipeline within which another smaller diameter tubular section requires to be secured or a pipeline within which another smaller diameter tubular section requires to be centralised.
22. A method of setting a morphed sleeve in a well bore according to any one of claims 18 to 21 wherein step (d) includes the step of pumping fluid through the tubular member and through multiple ports in the tubular body to access the chamber.
23. A method of setting a morphed sleeve in a well bore according to any one of claims 18 to 22 wherein the method includes the step of rupturing a disc at a valve in the port to allow fluid to enter the chamber when the pressure reaches a desired value.
24. A method of setting a morphed sleeve in a well bore according to any one of claims 18 to 23 wherein the method includes the steps of running in an activation fluid delivery tool, creating a temporary seal above and below the port and injecting fluid from the tool into the chamber via the port.