Improved Isolation Barrier

Abstract

An apparatus (10) and method for securing a tubular (12) within another tubular or borehole (80), creating a seal across an annulus in a wellbore (80), and centralising or anchoring tubing within a wellbore. A sleeve (14) is arranged on a tubular body (12) to create a chamber (16) therebetween. A port (18) provides fluid access through the body to the chamber. The chamber is filled with a swellable material (20). Thus the sleeve can be morphed to secure it to a well bore wall by the use of fluid pressure and an activated swellable material, the swellable material being used to support the sleeve to maintain a seal between the sleeve and well bore wall to form an isolation barrier.

Description

The present invention relates to an apparatus and method for securing a tubular within another tubular or borehole, creating a seal across an 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 a fluid pressure and an activated swellable material, the swellable material being used to support the sleeve to maintain a seal between the sleeve and well bore wall to form an isolation barrier.

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.

Another class of packers are swellable packers where a swellable elastomer is wrapped on a tubular body. Metal end rings may be located on the body to protect the swellable elastomer on run-in and prevent longitudinal extrusion of the elastomer so that swelling increases the outer original diameter of the swellable elastomer. The packers are simply run to depth on a tubing string and allowed to swell before production or injection operations begin. An advantage of swellable packers is their simplicity with no moving parts, but they have some major disadvantages. As the swellable material is exposed on the outer surface of the tubular body, fluid in the annulus will flow over the elastomer during run-in and risk early activation. As these swellable elastomers are activated by oil and/or water and water based fluids i.e. common oil field fluids, the well bore must be kept clear of the activating fluid until such time as the packer is in position and requires to be set. Additionally, these packers use the swellable elastomer to create the seal with the inner surface of the larger diameter cylindrical structure. Uniform swelling is assumed so that these packers are best used when a seal to another tubular is required. For open hole deployment, as swelling is achieved by absorption or diffusion of the fluid into the swellable material, when a seal is made at a first point on the borehole wall, sections of the outer surface of the elastomer may not be exposed to the fluid and thus swelling can be non-homogenous risking areas where a seal is not formed.

All these prior art packers have the same disadvantage in that they use an elastomer to create the seal against the outer generally cylindrical structure. Consequently, the elastomer must be exposed to well fluids in use and therefore they cannot be used where corrosive fluids are present, for example in chemical injection applications.

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 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 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 U.S. Pat. No. 7,306,033, which is 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.

In use, the pressure of fluid in the throughbore is increased sufficiently to enter the chamber and force the sleeve radially outwardly to morph to the generally cylindrical structure. Sufficient pressure has been applied when there is no return of fluid up the annulus which verifies that a seal has been achieved.

There are a number of difficulties in expanding a sleeve in this manner. Initially, sufficient pressure must be generated at the location of the port. This is done by increasing fluid pressure at surface and it is difficult to predict what the pressure will be at what may be a significant depth in the well where the sleeve is positioned. Alternatively, a setting tool can be run but this requires intervention and careful positioning of the setting tool at the port. To ensure sufficient pressure is generated, it is typical to set these sleeves by applying maximum pressure to the sleeve. However, there is a risk that the pressure could be high enough to rupture the sleeve.

Additionally, pressure must be sealed in the chamber to maintain inflation and, as the morphed sleeve may be needed for the life of the well, keeping the pressure at a set value in the chamber is required. Leakage through trapped debris in the check valve at the port can cause a slow loss of pressure. Temperature changes when the well is operated can cause pressure variations in the chamber. Consequently, though the sleeve has been plastically deformed and will therefore hold its new shape, if a sufficient pressure differential is created across the sleeve wall, there is a possibility that fracture or collapse can occur and the seal may be lost.

It is therefore an object of at least one embodiment of the present 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 generally cylindrical structure;
a sleeve member positioned on the exterior of the tubular body and sealed thereto 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:
a swellable material is located in at least a portion of the chamber;
the swellable material being activated to swell by fluid entering the chamber and the swelled material supporting the morphed sleeve member against the inner surface of the larger diameter structure.

In this way, the fluid pressure is not critical as it is used to activate the swellable material, and the swelling material will itself increase fluid pressure in the chamber. By having the swellable material contained in the chamber, exposure to the activating fluid can be controlled and there is no reliance on the swellable material to create the seal. Additionally, once the sleeve is morphed the swellable material supports the sleeve in the morphed position.

The term “swellable” and similar terms (such as “swelling”) are used herein to indicate an increase in volume of a material. Typically, this increase in volume is due to absorption or diffusion of molecular components of the fluid into the material itself, but other swelling mechanisms or techniques may be used, if desired. Note that swelling is not the same as expanding, although a material may expand as a result of swelling.

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.

The tubular body is preferably located coaxially within the sleeve and is 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 swellable material. 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 the swellable material is a swellable elastomer. The swellable material may be as known in the industry for swellable packers. Alternatively, the swellable material may be any composition which increases in volume on contact with a specified fluid e.g. bentonites such as sodium bentonite. The swellable material may be of a type which swells immediately on contact with the activating fluid. Alternatively, the swellable material may swell following a predetermined time after contact with the activating fluid.

The swellable material may be arranged as a sleeve around the body. In this way, the assembly is simple to construct as the morphable sleeve will locate over the swellable sleeve and contain it with the chamber. Alternatively, the swellable material may be a plurality of swellable elements. In this way, the swell rate can be increased due to the increased contact area for the activating fluid. The swellable material may be attached to the exterior of the tubular body or may be free to move within the chamber. The swellable elements may be shaped as balls, cubes, strips or granules′.

Preferably, there is a plurality of ports arranged through the tubular body. In this way, activating fluid can reach the maximum amount of swellable material in the quickest time. The ports may be arranged circumferentially around the body. The ports may be arranged longitudinally along the body. In an embodiment, one or more channels are machined on the exterior of the tubular body at the chamber. The channels provide for fluid flow between the swellable material and the tubular body, increasing the potential contact surface area between the fluid and the swellable material.

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. 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, swelling can occur rapidly by the introduction of high pressure fluid in the knowledge that fluid flow will stop when the morphed pressure is reached. The valve preferably allows pressure to be bled off so that fluid trapped in the chamber will not increase in pressure if swelling is still continuing after the morphed pressure value is reached.

The morphed sleeve will have a chamber filled with swelled material and fluid. Swelling of the material will increase the pressure of the fluid and both will exert pressure to cause the sleeve member to move outwardly and morph against the inner surface of 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 swellable material 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) activating the swellable material with the fluid to create swelling of the material in the chamber;
• (f) causing the sleeve to move radially outwardly and morph against an inner surface of the larger diameter structure; and
• (g) supporting the morphed sleeve via the swelled material.

In this way, a selective seal is created between the morphed sleeve and the inner surface of the larger diameter structure, with the swellable material increasing the rate of expansion of the sleeve and supporting the morphed sleeve once it is expanded.

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 acting time for the swellable material.

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 swellable material.

Preferably, in step (e) activating the swellable material with the fluid creates immediate swelling of the material in the chamber. Alternatively, in step (e) activating the swellable material with the fluid creates swelling of the material in the chamber after a predetermined time. By delaying the onset of swelling, contact of fluid to all surfaces of the swellable material can be achieved before swelling occurs. In this way, optimum swelling of the material occurs.

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 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.

Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings of which:

FIG. 1 is a half cross-sectional view through an assembly according to an embodiment of the present invention;

FIG. 2 is a half cross-sectional view through the assembly of FIG. 1 when the sleeve is morphed to an inner wall of a well bore; and

FIG. 3 is a schematic illustration of a sequence for setting two sleeve 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 pressure balanced chambers, in use.

Reference is initially made to FIG. 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 swellable material, 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 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.

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 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 82 of the open borehole 80 first. The sleeve member 14 will continue to expand outwards into the spaces between the bands, thereby causing a 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.

A first end 42 of the sleeve 14 is attached to a stop 44 machined in the outer surface 36 of the body 12. Attachment is via pressure-tight connections to provide a seal. An O-ring seal (not shown) may also be provided between the inner surface 46 of the sleeve 14 and the outer surface 36 of the body 12 to act as a secondary seal or backup to the seal provided by the welded connection at the stop 44. Attachment could also be by means of a mechanical clamp. It will be appreciated that the sleeve 14 need not be attached to the stop 44.

A second stop 48 is arranged at a second end 50 of the sleeve 14. The second stop 48 may be clamped to the body 12 so that the sleeve 14 can be slid onto the body 12 over the second end during assembly. A seal 52 is provided at the outer surface 36 of the body 12 forward of the stop 48 so that the seal 52 is between the sleeve 14 and the body 12. This provides a sliding seal so that the end of the sleeve 14 is permitted to move towards the first end, relative to the body 12. Thus when the sleeve member 14 is caused to move in the radially outward direction, this causes simultaneous movement of the sliding seal 52, which has the advantage in that the thickness of the sleeve 14 is not further thinned by the radially outwards expansion.

Stop 44 together with the inner surface 46 of the sleeve 14 and the outer surface 36 of the body 12, define a chamber 16. The port 18 is arranged to access the chamber 16 and permit fluid communication between the throughbore 30 and the chamber 16.

Located within the chamber 16 is a swellable material 20. Swellable materials are known with swellable elastomers being commonly used in the industry. Compositions which increase in volume on contact with a specified fluid e.g. bentonites are known. While the compound sodium bentonite is more commonly used in drilling muds it may be used in the present application. While the swellable material 20 may be a swellable elastomer, any swellable material capable of swelling against the fluid pressures needed to morph the sleeve may be used. In this application, pressures in the region of 5,000 to 10,000 psi are required. The swellable material may be of a type which swells immediately on contact with an activating fluid. Alternatively, the swellable material may swell after a predetermined time after contact with an activating fluid. The swellable material 20 can be selected to activate with any desired fluid, but preferably will act with a known well fluid. In this way, the activation fluid is readily available when the sleeve 14 is to be morphed. Both hydrocarbon-based and water-based (including brine) activated swellable materials are known.

Swellable material 20 is provided as chips 24. The chips 24 are dropped into the chamber 16 before the second end 50 of the sleeve is sealed to the body 12. By providing the material 20 as chips 24 they are easy to locate in the chamber 16 and provide a greater surface area for contact with an activating fluid than a larger, single piece of material. While chips 24 are described, the material 20 may be of any shape such as balls, cubes, granules' or even strips arranged as rings around the outer surface 36 of the body 12. The swellable material 20 could alternatively be a single tubular section arranged as a swellable sleeve around the body 12 between the outer surface 36 of the body 12 and the inner surface 46 of the sleeve 14. The swellable material does not require to be attached to the body 12 and/or the sleeve 14 as any contact would limit the available surface area for activation. It should be noted that the sleeve 14 is not a coating applied to a swellable packer.

The swellable material 20 is activated by activation fluid entering the chamber 16 through the port 18. In the embodiment shown, the swellable material 20 is selected to swell after a predetermined time on contact with the activation fluid. This time delay allows the fluid to fill the chamber 16, surrounding all the chips 24 and thereby making contact with the entire surface area of swellable material 20 within the chamber 16.

The material 20 will swell by the process of absorption or diffusion of the activation fluid into the material 20. The process will continue until an equilibrium is reached between absorbed fluid and surrounding fluid. The initial unswollen volume of material 20 is therefore calculated on the basis of the expected volume of the chamber once morphed to be filled with swollen material 20 of a volume sufficient to maintain a desired pressure on the inner surface 46 of the sleeve 14. This is calculated from knowledge of the diameter of the body 12, the approximate diameter of the borehole 80 at the sleeve 14, the length of the sleeve 14, the material and thickness of the sleeve 14 and the properties of the swellable material 20. Ideally a majority of the volume of the unexpanded chamber is filled with unswollen swellable material.

On swelling, the material 20 increases in volume and thus each chip 24 will take up an increased volume of the chamber 16. The chips 24 will contact each other and as the volume of the chamber 16 is initially sized to be smaller than the volume of the swollen material 20, the chips 24 will exert a pressure both on the fluid and on the walls of the chamber 16. As the sleeve 14 is of a more ductile material than the body 14, the sleeve 14 will be forced radially outwardly by the pressure from the swelling material 20 and the fluid in the chamber 16. The sleeve 14 will be forced against the wall 82 of the well bore 80 and the outer surface 46 of the sleeve 14 will morph to the wall 82 with the contact therebetween creating a seal. This seal will be an annular seal around the assembly 10 and between the assembly 10 and the well bore 80. This is as illustrated in FIG. 2.

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 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, which will occur rapidly on swelling of the material 20, the valve 54 will close. As the morphed pressure value is not created by fluid pressure alone, a high fluid pressure can initially be used to fill the chamber 16, with the check valve 54 being set to close after a fixed amount of fluid has passed therethrough. The amount of fluid can be calculated as that required to take up the volume of the chamber 16 which isn't taken up with unswollen material 20 on deployment. It will be appreciated that the check valve 54 may not be required as the swollen material 20 may take up the inner volume and wholly support the morphed sleeve 14.

Also arranged at the port 32 is a rupture disc 56. The rupture disc isolates the swellable material 20 in the chamber 16 from fluids in the throughbore during run-in of the string. The rupture disc 56 is rated to a desired pressure at which fluid 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 and prevent premature swelling of the material 20. 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.

Reference will now be made to FIG. 3 of the drawings which provides an illustration of the 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 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 80d in order to provide an isolation barrier between the zones 80b,80d. Additionally a further assembly 10b 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 activates the swellable material 20 which increases in volume creating a pressure 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 material 20 can be set to swell before fluid pressure can exceed that which would expand and rupture the sleeve 14. Indeed the check valve 54 can be set to allow a calculated volume of fluid to enter the chamber before closing. When closed, the check-valve will trap any fluid remaining in the chamber 16. However, as the material 20 will have swollen to fill the volume of the morphed sleeve and still exert pressure on the sleeve 14, the material 20 will provide a support to the sleeve 14 and thus the presence of fluid to maintain a morphed fluid pressure value in the chamber is no longer required.

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 14,14b have effectively centered, secured and anchored the tubing string 76 to the borehole 80.

An alternative method of achieving morphing of the sleeve 14 is shown in 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 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 acts on the swellable material 20 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 FIG. 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 and the swelling material directly against the sleeve 14 causes the sleeve 14 to move radially outwardly and seal against a portion of the inner circumference of the borehole 80. The pressure within the chamber 16 continues to increase such that the sleeve 14 initially experiences elastic expansion 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 means being required.

Additionally, the fluid pressure is not critical as it is merely used to activate the material; by having the swellable material contained in the chamber, exposure to the activating fluid can be controlled and there is no reliance on the swellable material to create the seal; and, once the sleeve is morphed the swellable material can support the sleeve in the morphed position.

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 swellable material is used to both decrease the reliance on fluid pressure to morph the sleeve and provide support to the morphed sleeve as a barrier.

A further advantage of the present invention is that it provides a method for setting a sleeve in a well bore which uses well fluids to activate a swellable material in a metal sleeve to gain the advantages of a barrier of solid volume which can be used in corrosive environments.

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 the swellable material is described as a solid it may be a liquid which solidifies when swollen.

Claims

1. An assembly, comprising:

a tubular body arranged to be run in and secured within a larger diameter generally cylindrical structure;

a sleeve member positioned on the exterior of the tubular body and sealed thereto 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:

a swellable material is located in at least a portion of the chamber;

the swellable material being activated to swell by fluid entering the chamber and the swelled material supporting the morphed sleeve member against the inner surface of the larger diameter structure.

2. An assembly according to claim 1 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.

3. An assembly according to claim 1 wherein the tubular body is located coaxially within the sleeve and is part of a tubular string used within a wellbore.

4. An assembly according to claim 1 wherein the swellable material is a swellable elastomer.

5. An assembly according to claim 1 wherein the swellable material is of a type which swells immediately on contact with the activating fluid.

6. An assembly according to claim 1 wherein the swellable material is of a type which swells following a predetermined time after contact with the activating fluid.

7. An assembly according to claim 1 wherein the swellable material is arranged as a sleeve around the body.

8. An assembly according to claim 1 wherein the swellable material is a plurality of swellable elements.

9. An assembly according to claim 8 wherein the swellable elements are shaped as balls, cubes, strips or granules'.

10. An assembly according to claim 1 wherein the swellable material is attached to the exterior of the tubular body.

11. An assembly according to claim 1 wherein the swellable material is free to move within the chamber.

12. An assembly according to claim 1 wherein there is a plurality of ports arranged through the tubular body.

13. An assembly according to claim 12 wherein the ports are arranged circumferentially around the body.

14. An assembly according to claim 12 wherein the ports are arranged longitudinally along the body.

15. An assembly according to claim 1 wherein one or more channels are machined on the exterior of the tubular body at the chamber.

16. An assembly according to claim 1 wherein the port includes a barrier.

17. An assembly according to claim 16 wherein the barrier is a rupture disc which allows fluid to flow through the port at a predetermined fluid pressure.

18. An assembly according to claim 16 wherein the barrier includes a valve.

19. An assembly according to claim 18 wherein the valve is a one-way check valve.

20. (canceled)

21. 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 swellable material 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) activating the swellable material with the fluid to create swelling of the material in the chamber;

(f) causing the sleeve to move radially outwardly and morph against an inner surface of the larger diameter structure; and

(g) supporting the morphed sleeve via the swelled material.

22. (canceled)

23. (canceled)

24. (canceled)

25. (canceled)

26. (canceled)

27. (canceled)