Methods and Systems Using an Expandable Sleeve in a Casing for Forming a Zonal Hydraulic Isolation

Abstract

An expandable sleeve is used for providing support to an obturation member. The expandable sleeve and the obturation member form a hydraulic isolation in a casing. The expandable sleeve has preferably a small thickness or cross-section, which can allow for a large flow-through inner diameter after expansion. Also, the expandable sleeve is preferably short. Thus, mill-up operations that are performed when the expandable sleeve is no longer in use can be expedited or even eliminated in some cases.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of priority to U.S. provisional application Ser. No. 62/720,458 filed on Aug. 21, 2018, the content of which is incorporated herein by reference.

BACKGROUND

The disclosure relates generally to methods and systems using an expandable sleeve in a casing. The disclosure relates more particularly to methods and systems in which the expandable sleeve is used to provide support to an obturation member and, together with the obturation member, forms a hydraulic isolation in the casing.

Some examples of known expandable sleeves are described in U.S. Pub. No. 2017/0241231. The known sleeves are expanded using a gripping device located on the inner diameter of the sleeve that is engaged with and selectively released from a connecting device. A thruster connected to the expansion swage propels the expansion swage toward the connecting device in a direction referred to as the front-end direction. The known anchor sleeves include an anchoring element on a middle portion of the sleeves. The middle portion of the sleeves is partially expanded by the expansion swage, so that the sleeves may be anchored to a casing. The gripping device is released from the connecting device when the middle portion of the sleeves comes into interference contact with the casing. The partially expanded middle portion is used for landing a fracking ball. The known sleeves also include a sealing element on an end portion of the sleeves. As such, pressure may be increased in the wellbore above the sleeves, for a fracking operation.

Despite these advances in the art, there remains continuing need in the art for improved methods and systems using an expandable sleeve in a casing. Preferably, the improved methods and systems provide reduced cost, reduced length, and/or reduced mill-up times of the expandable sleeve, and optionally elimination of the mill-up operation of the expandable sleeve.

SUMMARY

The disclosure describes a method of using an expandable sleeve for providing support to an obturation member and for forming, together with the obturation member, a hydraulic isolation in a casing.

The method may comprise providing a sleeve. The sleeve may include a tubular body and a tubular seal. The tubular body may be essentially made of a plastically deformable material. The tubular body may have a longitudinal axis, a first end, a second end axially opposite the first end, an inner radial surface, and an outer radial surface. The inner radial surface may include a conical seat surface. The conical seat surface may extend axially between a base level and the first end of the tubular body. The tubular seal may comprise an elastomeric material. The tubular seal may have a longitudinal axis, a first end, and a second end axially opposite the first end. The tubular seal may be secured around the outer radial surface of the tubular body. A distance from the first end of the tubular seal to the first end of the tubular body may be less than or equal to a length of the tubular seal, and in some embodiments, the first end of the tubular seal may extend axially at least to the base level.

The method may comprise expanding the sleeve against a casing located in a wellbore drilled through an Earth formation. Expanding the sleeve against the casing may be performed by translating an expansion cone through an entirety of the sleeve in a direction from the second end of the tubular body to the first end of the tubular body.

The method may comprise forming an annular seal between the tubular body and the casing with the tubular seal.

The method may comprise landing an obturation member on the conical seat surface.

The method may comprise dissolving or milling the obturation member. The method may further comprise flowing fluids through the sleeve after dissolving or milling the obturation member. The method may further comprise passing a downhole tool through the sleeve after dissolving or milling the obturation member.

The disclosure describes a system for using an expandable sleeve.

The system may comprise a sleeve. The sleeve may include a tubular body and a tubular seal.

The tubular body may be essentially made of a plastically deformable material. The tubular body may have a substantially uniform thickness. The tubular body may have a longitudinal axis, a first end, a second end axially opposite the first end, an inner radial surface, and an outer radial surface. The inner radial surface may include a conical seat surface. The conical seat surface may extend axially between a base level and the first end of the tubular body.

The tubular seal may comprise an elastomeric material. The tubular seal may comprise means for increasing friction between the tubular body and a casing. The means for increasing friction may be bonded to or embedded into the elastomeric material. The tubular seal may have a longitudinal axis, a first end, and a second end axially opposite the first end. The tubular seal may be secured around the outer radial surface of the tubular body. An axial distance from the first end of the tubular seal to the first end of the tubular body may be less than or equal to an axial length of the tubular seal, and in some embodiments, the first end of the tubular seal may extend axially at least to the base level.

The first end of the tubular body may be enlarged such that an outer diameter of the first end of the tubular body may be larger than a minimum outer diameter of the tubular body below the tubular seal. The second end of the tubular body may be enlarged such that an outer diameter of the second end of the tubular body may be larger than an outer diameter of the tubular seal.

The system may comprise a setting tool. The setting tool may include a tool body. The tool body may have a chamber. The setting tool may also include a piston slidable within the chamber, and a mandrel joining the piston and to an expansion cone. The tool body may be configured to abut the first end of the tubular body. The second end of the tubular body may be configured to abut the expansion cone. The mandrel may be configured to pass through the tubular body.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more detailed description of the embodiments of the disclosure, reference will now be made to the accompanying drawings, wherein:

FIG. 1 is a sectional view of a system including a setting tool and a sleeve, illustrated in a configuration prior to an expansion of the sleeve;

FIG. 2 is a sectional view of the system shown in FIG. 1, illustrated in a configuration after the expansion of the sleeve;

FIG. 3 is a sectional view of the sleeve shown in FIG. 1 after the setting tool is pulled out of the well;

FIG. 4 is a sectional view of the sleeve shown in FIG. 3, after an obturation member is landed on the sleeve;

FIG. 5 is a perspective view of a sleeve in accordance with another embodiment;

FIG. 6 is a sectional view of the sleeve shown in FIG. 5, illustrated in a casing and supported by an expansion cone of a setting tool;

FIG. 7 is a perspective view of a sleeve in accordance with another embodiment;

FIG. 8 is a sectional view of the sleeve shown in FIG. 7, illustrated in a casing and supported by an expansion cone of a setting tool;

FIG. 9 is a perspective view of a sleeve in accordance with another embodiment;

FIG. 10 is a sectional view of the sleeve shown in FIG. 9, illustrated in a casing and supported by an expansion cone of a setting tool; and

FIGS. 11A-11G illustrate a sequence of steps of a method of using a sleeve in a fracking operation.

DETAILED DESCRIPTION

It is to be understood that the following disclosure describes several exemplary embodiments for implementing different features, structures, or functions of the invention. Exemplary embodiments of components, arrangements, and configurations are described below to simplify the disclosure; however, these exemplary embodiments are provided merely as examples and are not intended to limit the scope of the invention. Additionally, the disclosure may repeat reference numerals and/or letters in the various exemplary embodiments and across the Figures provided herein. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various exemplary embodiments and/or configurations discussed in the various Figures. Finally, the exemplary embodiments presented below may be combined in any combination of ways, i.e., any element from one exemplary embodiment may be used in any other exemplary embodiment, without departing from the scope of the disclosure.

All numerical values in this disclosure may be approximate values unless otherwise specifically stated. Accordingly, various embodiments of the disclosure may deviate from the numbers, values, and ranges disclosed herein without departing from the intended scope. Moreover, the formation of a first feature over or on a second feature in the description that follows may include embodiments in which the first and second features are formed in direct contact, and may also include embodiments in which additional features may be formed interposing the first and second features, such that the first and second features may not be in direct contact.

FIG. 1 illustrates an embodiment of a system that uses an expandable sleeve in a casing 10 for forming zonal hydraulic isolation. The system shown in FIG. 1 comprises a setting tool, which includes a tool body 12 having a chamber 14, a piston 16 slidable within the chamber 14, and a mandrel 18 joining the piston 16 and to an expansion cone 20. As shown, the tool body 12 and/or the mandrel 18 may be made from several parts assembled with threaded connections. A set of shear pins or similar feature (not shown) may initially retain the mandrel 18 in the tool body 12 to prevent premature setting of the expandable sleeve. The setting tool may be conveyed by wireline in the casing 10. For example, the setting tool may be similar to setting tools that are commonly used in fracking plug/bridge plug operations.

The expandable sleeve can be designed with few elements to reduce cost. As shown, the expandable sleeve comprises a tubular body 22 and a tubular seal 24 secured (e.g., bonded) around the outer radial surface of the tubular body 22. The tubular body 22 and the tubular seal 24 have the same longitudinal axis 34.

Compared to known expandable sleeves, the expandable sleeve preferably has a smaller thickness or cross-section. The smaller thickness or cross-section can allow for a large flow-through inner diameter. For example, the flow-through inner diameter after expansion may be on the order of 90% of the diameter of the casing 10. Also, compared to known expandable sleeves, the tubular body 22 can be shorter, for example approximately six inches long. The smaller thickness or cross-section, as well as the shorter length of the expandable sleeve, can allow expediting or even eliminating mill-up operations when the expandable sleeve is no longer in use.

The tubular body 22 can essentially be made of a plastically deformable material, such as steel. The inner radial surface of the tubular body 22 includes a conical seat surface 26 that extends axially between a base level 28 and the top end of the tubular body 22. The tubular body 22 preferably has a substantially uniform thickness, for example in the order of four hundred mils. As such, the force required for expanding the tubular body 22 may be almost constant.

The tubular seal 24 comprises an elastomeric material. The top end of the tubular seal 24 extends axially at least to the base level 28. As such, the top end of the tubular seal 24 can be at approximately the same axial location as the seal created by an obturation member 36 (shown in FIG. 4) dropped on the conical seat surface 26. This configuration may assists in preventing burst or collapse failure modes during pressurization of a zone of the casing 10 that is hydraulically isolated with the expandable sleeve and the obturation member 36, even when the thickness or cross-section of the tubular body 22 is smaller than known expandable sleeves and/or even when the plastically deformable material making the tubular body 22 is a steel having a low yield strength (e.g., less than one hundred and ten kpsi, and optionally less than ninety kpsi).

In other embodiments, the top end of the tubular seal 24 may not extend axially at least to the base level 28. However, the distance from the top end of the tubular seal 24 to the top end of the tubular body 22 is preferably less than or equal to the axial length of the tubular seal 24. This configuration may still reduce the axial gap between the seal created by an obturation member 36 dropped on the conical seat surface 26 and the top end of the tubular seal 24, and may be sufficient to prevent burst or collapse failure modes during pressurization of a zone of the casing 10 that is hydraulically isolated with the expandable sleeve and the obturation member 36. In addition, this configuration may leave a sufficient axial length of the tubular body 22 to avoid that the tubular seal 24 extrudes beyond the top end of the tubular body 22 when the tubular seal 24 is compressed against the casing 10.

In some embodiments, the tubular seal 24 may consist essentially of an elastomeric material. The friction created by the elastomeric material being compressed against the casing 10 may be sufficient to resist the pressure loads applied to the obturation member 36, sometimes for sealing pressures up to fifteen kpsi. However, in other embodiments that may be more suitable in high-pressure, high-temperature environments, the tubular seal 24 can optionally further comprise means for increasing friction between the tubular body 22 and the casing 10. For example, the means for increasing friction can be bonded to or embedded (e.g., compounded) into the elastomeric material. The means for increasing friction can include embedded wire mesh, abrasive particulates, epoxy inclusions, coatings, etc. . . . , and their combinations. The means for increasing friction may be provided only on or in one or more portions of the tubular seal 24, such as on or in one or more disjoint portions distributed around a circumference of the tubular seal 24.

FIGS. 1 and 2 illustrate the expansion of the sleeve formed by the tubular body 22 and the tubular seal 24 against the casing 10. As shown in FIG. 1, during conveyance, the tool body 12 is configured to abut the top end of the tubular body 22, the bottom end of the tubular body 22 is configured to abut the expansion cone 20, and the mandrel 18 is configured to pass through the tubular body 22. Optionally, the bottom end of the tubular body 22 is enlarged such that an outer diameter 32 of the bottom end is larger than an outer diameter of the tubular seal 24. As such, the outer diameter 32 may provide a gauge surface that may protect the tubular seal 24 against scratching during conveyance in the casing 10. The setting tool may be pumped or dropped by gravity below a target fracture location within the casing 10. When triggered, the setting tool can translate the expansion cone 20 through the inner diameter of the sleeve, causing the tubular body 22 to plastically deform and expand. As shown in FIG. 2, the expansion of the sleeve is performed by translating the expansion cone 20 through an entirety of the sleeve in a direction from the bottom end of the tubular body 22 to the top end of the tubular body 22.

FIGS. 3 and 4 illustrate the formation of a hydraulic isolation in the casing 10. As shown in FIG. 3, once the setting tool is pulled out of the casing 10, the tubular seal 24 still dads against the casing 10 below the target fracture location, can form a seal between the tubular body 22 and the casing 10, and can provide an anchor to the tubular body 22 against the casing 10. As shown in FIG. 4, an obturation member 36 (e.g., a ball, a dart) is disposed or dropped in the bore traversing the sleeve. The obturation member 36 can be made of drillable (e.g., phenolic) material, degradable (e.g., phosphoric) material, or other material. The post expanded geometry of the conical seat surface 26 can be optimized to provide adequate seal once the obturation member 36 is seated. As such, for example, during fracking operations, the sleeve can support the obturation member 36 (shown in FIG. 4), provide a hydraulic isolation between the zones above and below the obturation member 36, and resist the pressure loads applied to the obturation member 36. In other words, the obturation member 36 can provide complete hydraulic isolation and allow for a pressure increase in a zone sealed above the expandable sleeve relative to a pressure in a zone below the expandable sleeve. Optionally, the pressure increase may cause fracking of a formation in the zone sealed above the expandable sleeve.

The expandable sleeve may be used in applications other than fracking, such as for patching a casing, or as a support for the obturation member 36 in non-fracking applications. Regardless of the application, the sleeve may be expanded using a hydraulic or mechanical setting tool conveyed on drill pipe, coil tubing, stick pipe, or other conveyance methods. The expansion could be performed in a bottom-up or top-down direction. The seal completion could be formed by dropping a ball, a dart, or utilizing a detachable expansion cone.

FIGS. 5 and 6 illustrate an expandable sleeve that includes inserts or buttons 38, which may penetrate the inner diameter of the casing 10 to increase friction between the tubular body 22 and the casing 10 upon expansion of the sleeve. The inserts or buttons 38 can be provided as an addition to the tubular seal 24 consisting essentially of an elastomeric material, or to the tubular seal 24 further comprising other means for increasing friction bonded to or embedded (e.g., compounded) into the elastomeric material. The inserts or buttons 38 can be made of metal carbide, hardened steel, ceramic, or other hardened material. Optionally, the inserts or buttons 38 are inserted, press fit or bonded into pockets formed in the tubular body 22 of the expandable sleeve.

In some embodiments, the inserts or buttons 38 may be separated from the tubular seal 24, as shown in FIGS. 5 and 6. As mentioned before, the elastomeric material in the tubular seal 24 is compressed between the casing 10 and the tubular body 22 to form a seal therebetween. The combined friction created by the elastomeric material and the mechanical penetration of the inserts or buttons 38 may achieve a sufficient resistance to axial loads generated by large pressure differentials (e.g., more than fifteen kpsi) across the obturation member 36 (similar to the one shown in FIG. 4), even in high-temperature environments. In other embodiments, the inserts or buttons 38 may be molded into, bonded to, or embedded into the elastomeric material of the tubular seal 24 (not shown).

FIGS. 7 and 8 illustrate an expandable sleeve that includes slips 40 having wickers on their outer radial surfaces, which may also penetrate the inner diameter of the casing 10 to increase friction between the tubular body 22 and the casing 10 upon expansion of the sleeve. The slips 40 can be provided as an addition to the tubular seal 24 consisting essentially of an elastomeric material, or to the tubular seal 24 further comprising other means for increasing friction bonded to or embedded (e.g., compounded) into the elastomeric material. The slips 40 can be made of metal, such as hardened steel, or may be made of combinations of materials, such as combination of steel and one or more of metal carbide, hardened steel, ceramic, or other hardened material. Optionally, the slips 40 are provided on ramp surfaces 46 formed on the outer radial surface of the tubular body 22, below shoulders 44. The slips 40 may be held in place using dowel pins, screws, or may be manufactured as a continuous ring that is designed to break into segments under hoop load. The wickers of the slips 40 may be coated or treated in a manner to increase their hardness. A radial spring (not shown) may be provided underneath the slips 40. This radial spring may assist in maintaining frictional engagement of the slips 40 with the casing 10 during and after expansion of the expandable sleeve, such as during fracking operations.

In some embodiments, the slips 40 may be separated from the tubular seal 24, as shown in FIGS. 5 and 6. As mentioned before, the elastomer material in the tubular seal 24 is compressed between the casing 10 and the tubular body 22 to form a seal therebetween. Again, the combined friction created by the elastomeric material and the mechanical penetration of the slips 40 may achieve a sufficient resistance to axial loads generated by large pressure differentials across the obturation member 36, even in high-temperature environments. In other embodiments, the slips 40 may be molded into, bonded to, or embedded into the elastomeric material of the tubular seal 24 (not shown).

A lip 42 may optionally protrude from the outer radial surface of the tubular body 22. The lip 42 can be designed to be compressed against the casing 10 during expansion, and to deform. As such, the lip 42 may function as a loading surface during expansion. The lip 42 may also function as a backup ring for the tubular seal 24, reducing an extrusion gap between the tubular body 22 and the casing 10. Alternatively, the tubular body 22 may include other anti-extrusion devices, such as split rings or petal rings (not shown).

FIGS. 9 and 10 illustrate an expandable sleeve that includes a set of slips 40 having hardened wickers. The slips 40 are segmented, and are bonded to the elastomeric material forming the tubular seal 24. As such, the elastomer material can hold the slips 40 in place during conveyance and deployment of the expandable sleeve. Further, a layer 54 of elastomeric material functioning as a radial spring is provided underneath the slips 40. The layer 54 of elastomeric material may assist in maintaining frictional engagement of the slips 40 with the casing 10 during and after expansion of the expandable sleeve, such as during fracking operations. The layer 54 may permit the expandable sleeve to be usable in different casings having a large range of inner diameters, such as in standard API casings as well as in re-fracking liners.

After expansion, the tubular seal 24 having the slips 40 bonded thereto performs both the function of sealing the tubular body 22 against the casing 10 and the function of increasing the friction between the tubular body 22 and the casing 10.

As shown, the top end of the tubular body 22 is enlarged such that an outer diameter 56 of the top end of the tubular body 22 is larger than a minimum outer diameter 58 of the tubular body 22 below the tubular seal 24. This enlargement may be used to promote occurrence of the seal between the tubular body 22 and the casing 10 at the top end of the tubular body 22 by generating a local pressure increase in tubular seal 24 during and/or after the expansion of the expandable sleeve, or in other words, by pinching the tubular seal 24. The pressure may further be increased by the radial load generated by the obturation member 36 seating or pressing against the conical seat surface 26.

Further, in cases where the bond between the tubular body 22 and the tubular seal 24 accidentally shears away after the slips 40 are anchored against the casing 10, and the tubular body 22 slides downward through the tubular seal 24 and the slips 40, the enlarged top end of the tubular body 22 may limit the amount by which the tubular body 22 can slide by pressing against the slips 40.

Any combination of features of the embodiments disclosed herein may be implement in the design of an expanded sleeve.

FIGS. 11A-11G illustrate a sequence of steps of a method of using the expandable sleeve described herein in a casing. In the method as shown, the expandable sleeve is used to provide support to an obturation member and, together with the obturation member, forms a hydraulic isolation in the casing. Also, in the method as shown, a formation is fracked.

In FIG. 11A a tool string comprising a setting tool including a tool body 12 and an expansion cone 20 and, above the setting tool, a perforation gun 48, is pumped or dropped by gravity below a target fracture location within the casing 10. The setting tool conveys an expansion sleeve formed by a tubular body 22 and a tubular seal 24. During conveyance, the top end of the tubular body 22 abuts the tool body 12 of the setting tool, the bottom end of the tubular body 22 abuts the expansion cone 20. In FIG. 11B, the expansion sleeve is set in the casing. The expansion of the sleeve is performed by translating the expansion cone 20 through an entirety of the sleeve in a direction from the bottom end of the tubular body 22 to the top end of the tubular body 22. In FIG. 11C, the perforating gun is used to perforate the casing above the sleeve. In FIG. 11D, the tool string is then pulled out of the hole. A perforation 50 is formed above the expansion sleeve. In FIG. 11E, an obturation member 36 (e.g., a degradable ball) is pumped. In FIG. 11F, the obturation member 36 sits on the sleeve and forms a seal. Fracking fluid and proppant 52 is pumped in a zone above the obturation member 36 that is hydraulically isolated from a zone below the obturation member 36. Pressure in the zone above the obturation member 36 is applied to the formation around the perforation 50. The formation may be fracked under the pressure. In FIG. 11G, the steps illustrated in FIGS. 11A-11F are repeated, so that multiple expansion sleeves and obturation members 36 form a series of seal along the casing 10.

After the fracking operation is complete, the obturation member(s) can then be milled or dissolved. In some cases, there may not be a need to mill out the expandable sleeve(s) including the tubular body and the tubular seal after the obturation member(s) is milled or dissolved. As such, the fracked formation may flow back through the sleeve. Also, because the flow-through inner diameter of the expandable sleeve(s) after expansion is sufficiently large, a downhole tool (a casing clean-up tool) can be passed through the expandable sleeve. Even if the expandable sleeve(s) are milled, the milling is expedited because of the reduced amount of material that is used for making the expandable sleeve(s).

While the disclosure is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and description. It should be understood, however, that the drawings and detailed description thereto are not intended to limit the claims to the particular form disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the scope of the claims.

Claims

1. A method, comprising:

providing a sleeve, the sleeve including: a tubular body, the tubular body being essentially made of a plastically deformable material, the tubular body having a longitudinal axis, a first end, a second end axially opposite the first end, an inner radial surface, and an outer radial surface, wherein the inner radial surface includes a conical seat surface; and a tubular seal, the tubular seal comprising an elastomeric material, the tubular seal having a longitudinal axis, a first end, and a second end axially opposite the first end, the tubular seal being secured around the outer radial surface of the tubular body, wherein a distance from the first end of the tubular seal to the first end of the tubular body is less than or equal to a length of the tubular seal;

expanding the sleeve against a casing located in a wellbore drilled through an Earth formation;

forming an annular seal between the tubular body and the casing with the tubular seal; and

landing an obturation member on the conical seat surface.

2. The method of claim 1 wherein the conical seat surface extends axially between a base level and the first end of the tubular body, and wherein the first end of the tubular seal extends axially at least to the base level.

3. The method of claim 1 wherein expanding the sleeve against the casing is performed by translating an expansion cone through an entirety of the sleeve in a direction from the second end of the tubular body to the first end of the tubular body.

4. The method of claim 1 further comprising dissolving or milling the obturation member.

5. The method of claim 4 further comprising flowing fluids through the sleeve after dissolving or milling the obturation member.

6. The method of claim 4 further comprising passing a downhole tool through the sleeve after dissolving or milling the obturation member.

7. A system, comprising:

a sleeve, the sleeve including: a tubular body, the tubular body being essentially made of a plastically deformable material, the tubular body having a longitudinal axis, a first end, a second end axially opposite the first end, an inner radial surface, and an outer radial surface, wherein the inner radial surface includes a conical seat surface; and a tubular seal, the tubular seal comprising an elastomeric material, the tubular seal having a longitudinal axis, a first end, and a second end axially opposite the first end, the tubular seal being secured around the outer radial surface of the tubular body, wherein an axial distance from the first end of the tubular seal to the first end of the tubular body is less than or equal to an axial length of the tubular seal; and

a setting tool, the setting tool including a tool body having a chamber, a piston slidable within the chamber, and a mandrel joining the piston and to an expansion cone,

wherein the tool body is configured to abut the first end of the tubular body, the second end of the tubular body is configured to abut the expansion cone, and the mandrel is configured to pass through the tubular body.

8. The system of claim 7 wherein the conical seat surface extends axially between a base level and the first end of the tubular body, and wherein the first end of the tubular seal extends axially at least to the base level.

9. The system of claim 7 wherein the tubular seal comprises means for increasing friction between the tubular body and a casing, the means for increasing friction being bonded to or embedded into the elastomeric material.

10. The system of claim 7 wherein the tubular body has a substantially uniform thickness.

11. The system of claim 7 wherein the second end of the tubular body is enlarged such that an outer diameter of the second end of the tubular body is larger than an outer diameter of the tubular seal.

12. The system of claim 7 wherein the first end of the tubular body is enlarged such that an outer diameter of the first end of the tubular body is larger than a minimum outer diameter of the tubular body below the tubular seal.