High pressure expandable packer

Abstract

A packer device includes a central packer mandrel and radially surrounding expansion mandrel that carries a suitable engagement profile for engaging the surrounding casing or other tubular member. A material chamber is defined between the expansion mandrel and the packer mandrel and is filled with a filler material. In currently preferred embodiments, the filler material comprises a pliable solid, a gel or colloid, or a liquid. A setting mechanism radially expands the expansion mandrel so that the engagement profile of the expansion mandrel is brought into engagement with the surrounding tubular.

Description

BACKGROUND OF THE INVENTION

This application is a continuation-in-part of U.S. patent application Ser. No. 10/117,521 filed on Apr. 5, 2002.

1. Field of the Invention

The invention relates generally to wellbore packer assemblies and, in particular aspects, to packer devices that are set within a wellbore by radial expansion.

2. Description of the Related Art

Traditional packers are comprised of an elastomeric sealing element and at least one mechanically set slip. Typically, a setting tool is run in with the packer to set it. The setting can be accomplished hydraulically due to relative movement created by the setting tool when subjected to applied pressure. This relative movement causes the slips to ride up on cones and extend into biting engagement with the surrounding tubular. At the same time, the sealing element is compressed into sealing contact with the surrounding tubular. The set can be held by a body lock ring, which would prevent the reversal of the relative movement that caused the packer to be set in the first instance.

As an alternative to applying pressure through the tubing to the setting tool to cause the packer to set, another alternative was to run the packer in on wire line with a known electrically-operated setting tool, such as an “E-4”-style setting tool that is available commercially from Baker Oil Tools of Houston, Tex. In setting the packer device, a signal fires the E-4 causing the requisite relative movement for setting. If the packer device is of a retrievable type, a retrieving tool could later be run into the set packer and release the grip of the lock ring and allow movement of the slips back down their respective cones and a stretching out of the sealing element so that the packer device can be removed from the well.

In the past, sealing has been suggested between an inner and outer tubular with a seal material in between. That technique, illustrated in U.S. Pat. No. 5,6,098,717, required the outer tubular or casing to be expanded elastically and the inner tubular to be expanded plastically. The sealing force arose from the elastic recovery of the casing being greater than the elastic recovery of the inner tubular, thus putting a net compressive force on the inner tubular and the seal. Other expansion techniques are described in U.S. Pat. Nos. 5,348,095; 5,366,012; and 5,667,011.

One problem with conventional packer devices arises when the packer device is used in high temperature conditions. Non-metallic elements tend to extrude from the packer device over time, compromising their ability to maintain a fluid seal. Additionally, there is a need for a packer that can remain reliably set in the presence of high pressure in the annulus above the packer. High pressure within the annulus acts upon the packer element and slips to urge them toward a radially retracted, and unset, position.

Additionally, the presence of ramps on the outer surface of a packer mandrel for setting the slips necessitates a reduction in the available interior bore diameter. As a result, some packer designs seek to create an engagement of packer element slips or wickers by direct radial expansion of the slips or wickers. Examples of such designs are found in a parent application to this one, U.S. Patent Publication No. US 2005/0028989 A1. This Publication describes packer devices that are set by radially expanding an outer expansion mandrel in response to fluid pressure from the flowbore. In one embodiment, shown in FIGS. 4a-4d and 5a-5d, pressure within the flowbore is used to actuate a plurality of setting pistons. The setting pistons create a pressure inside of the expansion mandrel that urges it outwardly into a set condition. Once the expansion mandrel has been set, the setting pressure within the flowbore may be reduced. The ability of this type of packer to remain set is largely dependent upon the deformed expansion mandrel retaining its deformed shape. A suitably high annulus pressure will tend to urge the expansion mandrel toward an unset position and, in the absence of offsetting flowbore pressure, the packer device can become unset or, at least, prone to leakage

The present invention addresses the problems of the prior art.

SUMMARY OF THE INVENTION

The invention provides an improved packer device and methods of setting such a device within a wellbore. The exemplary packer device of the present invention is suitable for use in high temperature conditions, since there are essentially no elastomeric sealing components that would tend to fail in response to high temperatures. Additionally, the packer device will remain reliably set even in the presence of high annulus pressures that would tend to urge the packer device back to an unset condition.

In a preferred embodiment, the exemplary packer device includes a central packer mandrel and a radially surrounding expansion mandrel that carries a suitable engagement profile for engaging the surrounding casing or other tubular member. A material chamber is defined between the expansion mandrel and the packer mandrel and is filled with a filler material. In currently preferred embodiments, the filler material comprises a pliable solid, a gel or colloid, or a liquid.

The packer device includes a setting mechanism for radially expanding the expansion mandrel so that the engagement profile of the expansion mandrel is brought into engagement with the surrounding tubular. In a currently preferred embodiment, the setting mechanism includes a piston member that is driven by flowbore pressure into the filler material. Driving the piston into the filler material causes the filler material to be axially compressed and, as a result, radially expanded. Radial expansion of the filler material drives the expansion mandrel radially outwardly so that the engagement profile is brought into sealing engagement with the surrounding tubular. A body lock ring is used to maintain the piston in its driven position. In practice, the packer device has proven to be very useful in situations where a packer device is needed that can retain its set and sealed position within a high annulus pressure condition.

BRIEF DESCRIPTION OF THE DRAWINGS

For a thorough understanding of the present invention, reference is made to the following detailed description of the preferred embodiments, taken in conjunction with the accompanying drawings, wherein like reference numerals designate like or similar elements throughout the several figures of the drawings and wherein:

FIG. 1 is a side, cross-sectional view of an exemplary packer assembly constructed in accordance with the present invention.

FIG. 2 is a side, cross-sectional view of the packer assembly shown in FIG. 1, now in a set position.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIGS. 1-2 depict an exemplary packer assembly 10 having a generally tubular central packer mandrel 12 that defines an axial flowbore 14 along its length. The packer mandrel 12 has an upper axial end 14 that is threaded so that the packer assembly 10 may be incorporated into a production tubing string 15. The central packer mandrel 12 is preferably formed of a very hard, non-malleable material, such as 4140 steel. A fluid passage, or flowbore, 16 is disposed through the central packer mandrel 12. The lower end 18 of the packer mandrel 12 is secured by threaded connection 20 to a lower sub 22. The lower sub 22 may have a lower end (not shown) that is also threaded so that the lower sub 22 may be connected to additional tubing members in a tubing string.

An expansion mandrel 24 radially surrounds an upper portion of the packer mandrel 12. The upper end 26 of the expansion mandrel 24 has a radially inner threaded surface 28 which engages a mating threaded exterior of the packer mandrel 12. At its lower end, the expansion mandrel 24 is affixed to the lower sub 22. The outer radial surface 30 of the expansion mandrel 24 presents an engagement surface 32 having a series of individual pointed wickers 34 that are shaped to provide a biting engagement with a surrounding tubular member 36. Optionally, an annular elastomeric fluid seal 38 could Is also carried on the engagement surface 32. The expansion mandrel 24 is preferably formed of 4140 steel also, but is typically of a lesser thickness than the central mandrel 12. Although the expansion mandrel 24 is shown in FIGS. 1 and 2 to be formed of a unitary piece, it is noted that it may also be made up of a number of separate components that, together, form the expansion mandrel 24. For example, the engagement surface 32 and wickers 34 might be formed on a separate outer sleeve.

A filler material chamber 40 is defined between the expansion mandrel 24 and the packer mandrel 12. A filler material 42 resides within the material chamber 40. The filler material 42 preferably comprises a quantity of gel, or a liquid, or a pliable solid. One suitable pliable solid for use as the filler material 42 is an elastomeric cylinder, particularly a cylinder fashioned of AFLAS™, a filler material 42 of plastic or TEFLON® might be used. A suitable liquid filler material would be water. An anti-extrusion ring 44 is preferably disposed at the upper axial end of the material chamber 40 to prevent the filler material 42 from escaping. Other mechanisms and arrangements for sealing of the material chamber 40, as are known in the art, may be employed to help prevent the escape of filler material 42 from the chamber 40, as well.

The packer assembly 10 is provided with a setting mechanism, generally indicated at 46 that moves the packer assembly 10 from an unset position, shown in FIG. 1, to a set position, shown in FIG. 2. The setting mechanism 46 includes a piston chamber 48 that is defined radially between the piston mandrel 12 and the lower sub 22. A fluid port 49 is disposed through the central mandrel 12 to allow fluid communication between the flowbore 16 and the piston chamber 48. An annular piston 50 is retained within the piston chamber 48 and axially moveable therewithin. The piston 50 carries fluid seals 52 on its inner and outer radial surfaces. The piston 50 also presents a displacement ring portion 54 that extends axially outwardly from the main piston body portion 56.

The piston 50 is preferably a force multiplying piston member that will create an applied setting pressure that is significantly greater than the pressure received by the piston 50. The main piston body portion 56 presents a force receiving area 58 at its lower end that is greater than the area presented by the distal end 60 of the displacement portion 54 (i.e., ten times the available area, as an example). As a result, the distal end 60 will generate a much higher applied pressure than that received that the area 58. For example, if 2000 psi of fluid pressure is applied to the force receiving area 58, approximately 20,000 psi. of setting pressure will be applied by the distal end 60.

A body lock ring 62, of known construction, is carried by the expansion mandrel 24. The body lock ring 62 provides a radially inner ratcheted surface that mates with a complimentary ratcheted surface on the displacement portion 54 of the piston 50. The body lock ring 62 ensures one way relative axial motion between the piston 50 and the expansion mandrel 24 such that, when the piston 50 has been moved to its set position, as shown in FIG. 2, it will be secured by the interlocking ratcheted surfaces from returning to the unset position shown in FIG. 1.

In operation to set the packer device 10, fluid pressure is increased within the flowbore 16 of the packer device. Typically, this is done by increasing fluid pressure from the surface of the well inside the production tubing string within which the packer device 10 is incorporated. If desired for setting, a ball or plug (not shown) may be dropped into the tubing string to land on a ball seat (not shown) below the packer device 10 within the tubing string. Pressure is then built up behind the ball or plug. Increased pressure within the flowbore 16 of the packer assembly 10 will be transmitted from the flowbore 16 through the fluid port 49 to the piston chamber 48. The increased pressure will bear upon the force receiving area 58 of the piston 50 and urge the piston 50 upwardly with respect to the expansion mandrel 24 until the piston 50 is moved to its set position, shown in FIG. 2. As the piston 50 is moved to its set position, the displacement portion 54 of the piston 50 extends into the material chamber 40. As a result, the filler material 42 is urged radially outwardly under the setting pressure generated by the piston 50 as well as the physical displacement of filler material 42 by the displacement portion 54. As the filler material 42 is displaced radially outwardly, the expansion mandrel 24 also expands radially outwardly until the engagement surface 32 is brought into biting engagement with the outer tubular 36. The terms “outer tubular” and “surrounding tubular” are used herein to designate generally any surrounding cylindrical surface into which the packer device 10 might be set. Ordinarily, the packer device 10 would be set within a string of steel casing lining the interior of a wellbore. However, a suitably sized packer device 10 could also be set within an inner production tubing string or liner. Alternatively, the “surrounding tubular” might be the uncased surface of a section of open hole within a wellbore.

It is noted that one could use mechanisms other than the particular setting assembly 46 for setting the packer device 10. For example, a striker module or power charge or a force intensifier device, both devices of known construction and operation, that are run into the flowbore 16 of the packer device 10. Numerous setting techniques are described in U.S. Patent Publication No. US 2005/0028989, which is owned by the assignee of the present invention and is herein incorporated by reference.

A significant design advantage of present device is that cones are not required to drive slips radially outwardly and into engagement with the surrounding casing 36. This means that for a given outside diameter for run-in, the packer can have a larger internal bore diameter than a design having cones to ramp the slips out. Additionally, the increased bore size possible with the present design comes with no significant reduction in the pressure rating of the packer device. A packer device constructed in accordance with the present invention could be rated, for example, at 20,000 psi. and be set with approximately 25,000 psi setting pressure. A further advantage is that the filler material 42 causes the expansion mandrel 24 to maintain biting engagement with the outer tubular 36. Annulus pressure does not cause the expansion mandrel 24 to collapse.

Those of skill in the art will recognize that the present invention provides not only a packer device 10 but also a system for selectively setting a packer element within a wellbore and a method for setting a packer device within a wellbore. To install the packer device 10 within a wellbore, the packer device 10 is incorporated into the tubing string 15 and is then disposed into the wellbore. The packer device 10 is positioned within the wellbore so that it is proximate the area wherein it is desired to set the packer device 10. At this point, the packer device 10 is set as described above.

Those of skill in the art will recognize that numerous modifications and changes may be made to the exemplary designs and embodiments described herein and that the invention is limited only by the claims that follow and any equivalents thereof.

Claims

1. A packer device for use within a wellbore and comprising:

a central packer mandrel defining an axial flowbore;

an expansion mandrel radially surrounding the central packer mandrel to define a filler material chamber between the expansion mandrel and the central packer mandrel;

an engagement profile formed on a radial exterior surface of the expansion mandrel for forming a biting engagement with a surrounding tubular within the wellbore;

a filler material disposed within the filler material chamber; and

a setting mechanism for selectively radially expanding the expansion mandrel relative to the central packer mandrel by displacing the filler material.

2. The packer device of claim 1 wherein the filler material comprises elastomer.

3. The packer device of claim 1 wherein the filler material comprises a pliable solid material.

4. The packer device of claim 3 wherein the solid material comprises a plurality of pellets.

5. The packer device of claim 4 wherein the pellets are formed of TEFLON®.

6. The packer device of claim 3 wherein the solid material comprises a cylinder of elastomeric material.

7. The packer device of claim 1 wherein the filler material comprises a liquid.

8. The packer device of claim 7 wherein the liquid comprises water.

9. The packer device of claim 1 wherein the filler material comprises a gel.

10. The packer device of claim 1 wherein the setting mechanism comprises a piston having a displacement portion for displacing the filler material and expansion mandrel radially outwardly and bringing the engagement profile into engagement with a surrounding tubular.

11. The packer device of claim 10 wherein the setting mechanism further comprises a body lock ring for maintaining the packer device in a set position.

12. A system for selectively setting a packer element in a wellbore, the system comprising:

a production tubing string;

a packer device incorporated into the tubing string; the packer device comprising:

a) a central packer mandrel defining an axial flowbore;

b) an expansion mandrel radially surrounding the central packer mandrel to define a filler material chamber between the expansion mandrel and the central packer mandrel;

c) a filler material disposed within the filler material chamber; and

d) a setting mechanism for selectively radially expanding the expansion mandrel relative to the central packer mandrel by displacing the filler material.

13. The system of claim 12 further comprising an engagement profile formed on a radial exterior surface of the expansion mandrel for forming a biting engagement with a surrounding tubular within the wellbore.

14. The system of claim 12 wherein the filler material is a material from the group consisting essentially of: a liquid, a gel, and a pliable solid.

15. The system of claim 12 wherein the filler material is a material from the group consisting of: a liquid, a gel, and a pliable solid.

16. The system of claim 12 wherein the setting mechanism comprises a piston having a displacement portion for displacing the filler material and expansion mandrel radially outwardly and bringing the engagement profile into engagement with a surrounding tubular.

17. The system of claim 12 wherein the setting mechanism further comprises a body lock ring for maintaining the packer device in a set position.

18. A method of setting a packer device within a wellbore comprising the steps of:

1) disposing a packer device within a wellbore, the packer device having: a) a central packer mandrel defining an axial flowbore; b) an expansion mandrel radially surrounding the central packer mandrel to define a filler material chamber between the expansion mandrel and the central packer mandrel, the expansion mandrel having an engagement profile formed on a radial exterior surface of the expansion mandrel for forming a biting engagement with a surrounding tubular within the wellbore; c) a filler material disposed within the filler material chamber; and

2) actuating a setting mechanism to displace the filler material and radially expand the expansion mandrel to secure the engagement profile with a surrounding tubular.

19. The method of claim 18 wherein the step of actuating a setting mechanism further comprises urging a piston having a displacement portion into the filler material to displace the filler material.

20. The method of claim 19 wherein the step of actuating a setting mechanism further comprises retaining the piston in a set position with a body lock ring.