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Publication numberUS20080156501 A1
Publication typeApplication
Application numberUS 11/647,677
Publication dateJul 3, 2008
Filing dateDec 29, 2006
Priority dateDec 29, 2006
Also published asCA2667344A1, WO2008082970A1
Publication number11647677, 647677, US 2008/0156501 A1, US 2008/156501 A1, US 20080156501 A1, US 20080156501A1, US 2008156501 A1, US 2008156501A1, US-A1-20080156501, US-A1-2008156501, US2008/0156501A1, US2008/156501A1, US20080156501 A1, US20080156501A1, US2008156501 A1, US2008156501A1
InventorsJustin P. Vinson, Dennis E. Kroll, David S. Bishop, Kevin W. Clark
Original AssigneeVinson Justin P, Kroll Dennis E, Bishop David S, Clark Kevin W
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Non-backed-up packing element system
US 20080156501 A1
Abstract
Well tool packing element systems that do not require a back-up element or component include a mandrel, an upper supporting member, a lower supporting member, a cantilever element, and a ramp element disposed on the mandrel. The cantilever element and ramp element are disposed on the mandrel with an interface angle between the cantilever element and the ramp element, the interface angle being less than 90 degrees, preferably in a range from 40 degrees to 60 degrees, and more preferably at an angle greater than 45 degrees. When an axial load is applied to upper and lower supporting members, cantilever element and ramp element are forced outward and into an inner wall surface of a casing to seal off the casing bore.
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Claims(24)
1. A packing element system for a well tool comprising:
a mandrel;
rigid upper and lower supporting members disposed on the mandrel; and
an annular deformable cantilever element and an annular deformable ramp element disposed adjacent one another on the mandrel between the upper and lower supporting members,
wherein the annular deformable cantilever element and the annular deformable ramp element have a conical interface between them, the interface forming an angle less than 90 degrees relative to an axis of the mandrel.
2. The packing element system of claim 1, wherein the angle is in the range from 40 degrees to 60 degrees.
3. The packing element system of claim 1, wherein the angle is greater than 45 degrees.
4. The packing element system of claim 1, wherein the annular deformable cantilever element has an outer surface having an axial length that is longer than an axial length of an outer surface of the annular deformable ramp element.
5. The packing element system of claim 1, wherein the annular deformable cantilever element has a supporting member interface, at least a portion of which is perpendicular to the axis of the mandrel.
6. The packing element system of claim 1, wherein the annular deformable ramp element with an axial length of an inner surface that is longer than an axial length of an inner surface of the annular deformable cantilever element.
7. The packing element system of claim 1, wherein the annular deformable ramp element has a supporting member interface, at least a portion of which is perpendicular to the axis of the mandrel.
8. The packing element system of claim 1, wherein the annular deformable cantilever element includes an inner surface in contact with the mandrel and a bevel at at least one end of the inner surface.
9. The packing element system of claim 8, wherein the inner surface of the annular deformable cantilever element has a bevel at each end of the inner surface.
10. The packing element system of claim 1, wherein the annular deformable ramp element includes an inner surface in contact with the mandrel and a bevel at at least one end of the inner surface.
11. The packing element system of claim 8, wherein the inner surface of the annular deformable ramp element has a bevel at each end of the inner surface.
12. The packing element system of claim 1, wherein one of the upper supporting member or the lower supporting member is stationary relative to the mandrel.
13. The packing element system of claim 1, wherein both the upper supporting member and the lower supporting member are slidingly engaged with the mandrel.
14. The packing element system of claim 1, further comprising a second annular deformable ramp element,
wherein the annular deformable cantilever element is disposed between said first mentioned annular deformable ramp element and the second annular deformable ramp element,
wherein the annular deformable cantilever element and the second annular deformable ramp element have a second conical interface between them, the second conical interface forming a second angle less than 90 degrees relative to an axis of the mandrel.
15. The packing element system of claim 1, wherein the upper supporting member and the lower supporting member are both cones.
16. The packing element of claim 1, wherein at least one of the upper supporting member or the lower supporting member is formed of a metal.
17. The packing element of claim 1, wherein one of the supporting members comprises a piston located within a cylinder and mounted to the mandrel for relative axial movement.
18. A packing element system for sealing a well tool against an outer tubular member, the packing element system comprising:
a mandrel having disposed thereon an upper supporting member and a lower supporting member, one of the supporting members being movable toward the other supporting member;
a cantilever element and a ramp element disposed between the upper and lower supporting members, each of the cantilever element and the ramp element having cylindrical inner and outer diameters, a supporting member end that interfaces with one of the supporting members, and a conical end, the conical ends interfacing with each other and defining a conical angle relative to an axis of the mandrel; and
the cantilever element and the ramp element each being formed of a deformable material so that axial movement of one of the supporting members toward a set position extrudes both the cantilever element and the ramp element into sealing contact with the outer tubular member.
19. The packing element system of claim 18, wherein at least a portion of each of the supporting member ends of the cantilever element and the ramp element is perpendicular to the axis of the mandrel.
20. The packing element system of claim 18, further comprising a second ramp element,
wherein the cantilever element is disposed between said first mentioned ramp element and the second ramp element,
wherein the cantilever element and the second ramp element have a second conical interface between them, the second conical interface forming a second angle less than 90 degrees relative to an axis of the mandrel.
21. A method of sealing a wellbore, the method comprising the steps of:
(a) running a string having a packing element system attached thereto into a bore of a wellbore having a wellbore casing, the packing element system having a cantilever element and a ramp element disposed along a mandrel having an axis, wherein the cantilever element is disposed against the ramp element to provide an interface between the cantilever element and the ramp element, the interface forming an angle less than 90 degrees;
(b) applying an axial load to force the cantilever element and the ramp element against each other, causing the ramp element to wedge under the cantilever element and force the cantilever element radially outward into sealing engagement with the wellbore casing; and
(c) continuing to apply the axial load causing the ramp element to move radially outward into sealing engagement with the wellbore casing.
22. The method of claim 21, wherein the cantilever element and the ramp element are formed of elastomeric materials.
23. The method of claim 21, wherein the angle is in the range from 40 degrees to 60 degrees.
24. The method of claim 21, wherein the angle is greater than 45 degrees.
Description
BACKGROUND

1. Field of Invention

The invention is directed to packing element systems for use in a casing string in a wellbore and, in particular, to packing element systems lacking a back-up component.

2. Description of Art

Referring to FIG. 1, prior packing element systems 10 include a housing or mandrel 11 with a packing element 12 disposed therein. Each end of packing element 12 includes housing or support 13 to facilitate elastic expansion of packing element 12 away from mandrel 11 when an axial load is placed on packing element 12 at axial load points 14. Each end of packing element 12 also includes two back-up elements 15, 16 each of which are shown as metal petal back-ups having bottom layer 17 and top layer 18, or a phenolic back-up (not shown), both of which are known in the art. Such prior packing element systems, comprising of a back-up element 15, have the shortcomings of increased manufacturing time, increased time to mill through the packing element system after its use is no longer required, increased formation of debris from the back-up element breaking during setting of the packing element system, increased tool length, high axial loading requirement to set the packing element system, and/or specialized components requirements, such as a TeflonŽ barrier in the case of a metal petal back-up element. These shortcomings result in increased costs associated with running and setting these prior packing element systems.

Accordingly, prior to the development of the packing elements systems disclosed herein, there has been no packing element system or method of setting a packing element system in a wellbore known to the inventors that does not require a back-up element. Therefore, the art has sought packing element systems and methods of setting a packing element system in a wellbore that: do not require a back-up element; decrease the costs associated with the manufacture, running-in, and setting of the packing element systems; permit setting of the packing element system with less axial loading; provide shortened manufacturing time; provide shortened mill time; do not require specialized components such as a TeflonŽ barrier; and reduce the length of prior packing element systems.

SUMMARY OF INVENTION

Broadly, the packing element systems disclosed herein include a sealing member having two components: a cantilever element and a ramp element. “Cantilever element” is used herein to mean the shape of the element as having at least one conical end and an axial dimension on its inner surface defined by its inner diameter that is less than the axial dimension on its outer surface defined by its outer diameter. “Ramp element” is used herein to mean the shape of the element as having at least one conical end and an axial dimension on its inner surface defined by its inner diameter that is greater than the axial dimension on its outer surface defined by its outer diameter.

The cantilever element and ramp element are disposed adjacent to each other at an angle less than 90 degrees and, preferably, greater than about 45 degrees. In a particularly preferred embodiment, the angle is in the range from 45 to 60 degrees, and more preferably at 50 degrees. The inclusion of a cantilever element and ramp element disposed adjacent and relative to each other at these angles allows the packing element system to effectively seal a casing string against the inner wall surface of a wellbore casing without the need for a back-up component.

The packing element systems and methods of setting a packing element system in a wellbore may have one or more of the following advantages: not requiring a back-up element; decreasing the costs associated with the manufacture, running-in, and milling out of the packing element systems; permitting setting of the packing element system with less axial loading; providing shortened manufacturing time; providing shortened mill time; not requiring specialized components such as a Teflon(& barrier; and reducing the length of prior packing element systems.

In one aspect, one or more of the foregoing advantages can be achieved through a packing element system for a well tool. The packing element system comprises a mandrel; rigid upper and lower supporting members disposed on the mandrel; and an annular deformable cantilever element and an annular deformable ramp element disposed adjacent one another on the mandrel between the upper and lower supporting members, wherein the annular deformable cantilever element and the annular deformable ramp element have a conical interface between them, the interface forming an angle less than 90 degrees relative to an axis of the mandrel.

A further feature of the packing element system is that the angle may be in the range from 40 degrees to 60 degrees. Another feature of the packing element system is that the angle may be greater than 45 degrees. An additional feature of the packing element system is that the annular deformable cantilever element may have an outer surface having an axial length that is longer than an axial length of an outer surface of the annular deformable ramp element. Still another feature of the packing element system is that the annular deformable cantilever element may have a supporting member interface, at least a portion of which is perpendicular to the axis of the mandrel. A further feature of the packing element system is that the annular deformable ramp element may have an axial length of an inner surface that is longer than an axial length of an inner surface of the annular deformable cantilever element. Another feature of the packing element system is that the annular deformable ramp element may have a supporting member interface, at least a portion of which is perpendicular to the axis of the mandrel. An additional feature of the packing element system is that the annular deformable cantilever element may include an inner surface in contact with the mandrel and a bevel at at least one end of the inner surface. Still another feature of the packing element system is that the inner surface of the annular deformable cantilever element may have a bevel at each end of the inner surface. A further feature of the packing element system is that the annular deformable ramp element may include an inner surface in contact with the mandrel and a bevel at at least one end of the inner surface. Another feature of the packing element system is that the inner surface of the annular deformable ramp element may have a bevel at each end of the inner surface. An additional feature of the packing element system is that one of the upper supporting member or the lower supporting member may be stationary relative to the mandrel. Still another feature of the packing element system is that both the upper supporting member and the lower supporting member may be slidingly engaged with the mandrel. A further feature of the packing element system is that the packing element system may further comprise a second annular deformable ramp element, wherein the annular deformable cantilever element is disposed between said first mentioned annular deformable ramp element and the second annular deformable ramp element, wherein the annular deformable cantilever element and the second annular deformable ramp element have a second conical interface between them, the second conical interface forming a second angle less than 90 degrees relative to an axis of the mandrel. Another feature of the packing element system is that the upper supporting member and the lower supporting member both may be cones. An additional feature of the packing element system is that at least one of the upper supporting member or the lower supporting member may be formed of a metal. Still another feature of the packing element system is that one of the supporting members may comprise a piston located within a cylinder and mounted to the mandrel for relative axial movement.

In another aspect, one or more of the foregoing advantages may be achieved through a packing element system for sealing a well tool against an outer tubular member. The packing element system comprises a mandrel having disposed thereon an upper supporting member and a lower supporting member, one of the supporting members being movable toward the other supporting member; a cantilever element and a ramp element disposed between the upper and lower supporting members, each of the cantilever element and the ramp element having cylindrical inner and outer diameters, a supporting member end that interfaces with one of the supporting members, and a conical end, the conical ends interfacing with each other and defining a conical angle relative to an axis of the mandrel; and the cantilever element and the ramp element each being formed of a deformable material so that axial movement of one of the supporting members toward a set position extrudes both the cantilever element and the ramp element into sealing contact with the outer tubular member.

A further feature of the packing element system is that at least a portion of each of the supporting member ends of the cantilever element and the ramp element may be perpendicular to the axis of the mandrel. Another feature of the packing element system is that the packing element system may further comprise a second ramp element, wherein the cantilever element is disposed between said first mentioned ramp element and the second ramp element, wherein the cantilever element and the second ramp element have a second conical interface between them, the second conical interface forming a second angle less than 90 degrees relative to an axis of the mandrel. An additional feature of the packing element system is that both the ramp element and the cantilever element may be formed from an elastomeric material. Still another feature of the packing element system is that the ramp element may be formed of a metal material and may have an o-ring to seat against the mandrel.

One or more of the foregoing advantages may also be achieved through the a method of sealing a wellbore. The method comprises the steps of: (a) running a string having a packing element system attached thereto into a bore of a wellbore having a wellbore casing, the packing element system having a cantilever element and a ramp element disposed along a mandrel having an axis, wherein the cantilever element is disposed against the ramp element to provide an interface between the cantilever element and the ramp element, the interface forming an angle less than 90 degrees; (b) applying an axial load to force the cantilever element and the ramp element against each other, causing the ramp element to wedge under the cantilever element and force the cantilever element radially outward into sealing engagement with the wellbore casing; and (c) continuing to apply the axial load causing the ramp element to move radially outward into sealing engagement with the wellbore casing.

A further feature of the method of sealing a wellbore is that the cantilever element and the ramp element may be formed of elastomeric materials. Another feature of the method of sealing a wellbore is that the angle may be in the range from 40 degrees to 60 degrees. An additional feature of the method of sealing a wellbore is that the angle may be greater than 45 degrees.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a cross-sectional view of a prior art packing element system.

FIG. 2 is a cross-sectional view of a specific embodiment of a packing element system disclosed herein shown in its initial or run-in position.

FIG. 3 is a cross-sectional view of the packing element system illustrated in FIG. 2 shown in its set position.

FIG. 4 is a cross-sectional view of another specific embodiment of a packing element system disclosed herein shown in its initial or run-in position.

FIG. 5 is a cross-sectional view of the packing element system illustrated in FIG. 4 shown in its set position.

FIG. 6 is a cross-sectional view of an additional specific embodiment of a packing element system disclosed herein shown in its initial or run-in position.

FIG. 7 is a cross-sectional view of the packing element system illustrated in FIG. 6 shown in its set position.

While the invention will be described in connection with the preferred embodiments, it will be understood that it is not intended to limit the invention to that embodiment. On the contrary, it is intended to cover all alternatives, modifications, and equivalents, as may be included within the spirit and scope of the invention as defined by the appended claims.

DETAILED DESCRIPTION OF INVENTION

Referring now to FIGS. 2-3, packing element system 20 is shown in its initial or run-in position (FIG. 2) and its set position (FIG. 3). Broadly, packing element system 20 includes five components or parts: cantilever element 22, ramp element 24, upper cone 26, and lower cone 28, all carried on mandrel 30. Cantilever element 22, ramp element 24, upper cone 26, and lower cone 28 are tubular members, each having an inner surface determined by an inner diameter that receives mandrel 30. As will be appreciated by persons of ordinary skill in the art, mandrel 30 is a tubular member carried on a casing string (not shown). Mandrel 30 can be secured to the casing string through any device or method known to persons of ordinary skill in the art. No back-up component such as component 15 shown in FIG. 1 is required.

Cantilever element 22 is a deformable element formed from a deformable material that is in contact with ramp element 24 at interface 32. Ramp element 24 also is a deformable element formed from a deformable material that may be the same deformable material used to form cantilever element 22. Cantilever element 22 and ramp element 24 slide relative to each other along interface 32 during setting of packing element system 20.

Interface 32 is a conical surface disposed at angle 34 relative to the axis of mandrel 30. Interface 32 results in the axial length of inner surface 21 of cantilever element 22 being shorter than axial length 50 of outer surface 23 of cantilever element. Inner surface 25 of ramp element 24 has a longer axial length than axial length 52 of outer surface 27 of ramp element 24.

In one embodiment, the axial length of inner surface 21 of cantilever element 22 is substantially equal to axial length 52 of outer surface 27 of ramp element 24. In another embodiment, inner surface 21 of cantilever element 22 has a greater axial length compared to axial length 52 of outer surface 27 of ramp element 24. In still another embodiment, the axial length of inner surface 21 of cantilever element 22 has a shorter axial length compared to axial length 52 of outer surface 27 of ramp element 24.

Moreover, cantilever element 22 and ramp element 24 may be substantially the same shape and size. In one particular embodiment, outer surface 23 of cantilever element 22 has a greater axial length 50 than axial length 52 of outer surface 27 of ramp element 24. In another particular embodiment, outer surface 23 of cantilever element 22 may be shorter along its axial length 50 than axial length 52 of outer surface 27 of ramp element 24. In still another embodiment, cantilever element 22 has a larger volume than ramp element 24. Alternatively, in yet another embodiment, ramp element 24 has a larger volume than cantilever element 22.

In the embodiment shown in FIG. 2, cantilever element 22 may include angled bevels 55, 56 disposed at the upper and lower ends, respectively, of cantilever element 22. Additionally, ramp element 24 may include angled bevels 57, 58 disposed at the upper and lower ends, respectively, of ramp element 24. Angled bevels 55, 56 and 57, 58 assist in the assembly of packing element system 20.

Additionally, cantilever element 22 and ramp element 24 may be formed of any material known by persons of ordinary skill in the art such as elastomers, rubbers, polymers, or thermoplastics. Preferably, both cantilever element 22 and ramp element 24 are formed of 95 durometer Nitrile. Additionally, cantilever element 22 and ramp element 24 may have any shape desired or necessary to provide the requisite compression, deformation, or “extrusion” to form the seal with inner wall surface 40 of casing 42. As shown in FIGS. 2-3, in a preferred embodiment, both cantilever element 22 and ramp element 24 are formed into the shape of a sleeve.

Angle 34 is less than 90 degrees because if angle 34 is 90 degrees, ramp element 24 will be unable to wedge under cantilever element 22 to force cantilever element 22 into inner wall surface 40 of casing 42. Preferably, angle 34 is greater than 45 degrees because when the angle is equal to or less than 45 degrees, the setting stroke required to move packing element system 20 from its run-in position (FIG. 2) to its set position (FIG. 3) in increased. As a result, a longer tool is required. Also, when angle 34 is less than 45 degrees, the radial force to create the seal with inner wall surface 40 of casing 42 is less effective. In other words, having angle 34 greater than 45 degrees provides a more effective seal compared to packing element systems 20 having angle 34 less than 45 degrees. Thus, by having angle 34 greater than 45 degrees, the stroke length required to move packing element system 20 from the run-in position (FIG. 2) to the set position (FIG. 3) is reduced and, therefore, the likelihood of over-extrusion is reduced. In a preferred embodiment, angle 34 is in the range from 45 degrees to 60 degrees and, in a particularly preferred embodiment, angle 34 is 50 degrees (shown in FIG. 2).

In addition to interface 32, cantilever element 22 is adjacent to, and interfaces with, upper support member 26, and ramp element 24 is adjacent to, and interfaces with, lower support member 28. It is to be understood, however, that the location of cantilever element 22 and ramp element 24 may be reversed. Thus, cantilever element 22 may be adjacent to, and interface with, lower support member 28, and ramp element 24 may be adjacent to, and interface with, upper support member 26.

Upper support member 26 and lower support member 28 may be any shape desired or necessary to provide transference of an axial load on cantilever element 22 and ramp element 24. As shown in FIGS. 2-3, both upper support member 26 and lower support member 28 are cones. In other embodiments, only one of upper support member 26 or lower support member 28 is a cone. In still other embodiments, one or both of upper support member 26 and/or lower support member 28 are rectangular-shaped cross sections. In still another embodiment, discussed in greater detail below, one or upper support member 26 or lower support member 28 is rectangular-shaped and the other of upper support member 26 or lower support member 28 is a piston-shaped sleeve.

Upper support member 26 and lower support member 28 are slidable relative to each other. Preferably, one of upper support member 26 or lower support member 28 is fixed to mandrel 30 against movement. The interface between upper support member 26 and cantilever element 22 is a flat surface perpendicular to the axis of mandrel 30. The interface between lower support member 28 and ramp element 24 is also a flat surface perpendicular to the axis of mandrel 30.

Upper support member 26 and lower support member 28 are rigid members formed from any material known by persons of ordinary skill in art, including, but not limited to, glass or carbon reinforced phenolic or metals such as steel. In embodiments in which the axial load is applied in only one direction, one of the upper support member 26 or lower support member 28 may be formed of a material that is less strong than the material used to form the cone that is directly receiving the axial load.

After packing element system 20 is disposed within a wellbore at the desired depth and location, packing element system 20 is actuated in the same manner as any other packer or packing element system known to persons of ordinary skill in the art, such as by applying a force to upper support member 26 axially in the direction of the arrow in FIG. 3 while lower support member 28 is stationary. Such axial load may also be applied in the opposite direction of the arrow in FIG. 3 on lower support member 26 while upper support member 26 is stationary or in both directions to both upper support member 26 and lower support member 28 with neither upper support member 26 nor lower support member 28 being stationary.

When an axial load is applied to upper support member 26 and cantilever element 22, ramp element 24 wedges under cantilever element 22 and forces it outward toward inner wall surface 40 of casing 42. As mentioned above, ramp element 24 and cantilever element 22 slide relative to each other along interface 32. As axial force increases, both cantilever element 22 and ramp element 24 are forced outward toward inner wall surface 40 of casing 42 until both cantilever element 22 and ramp element 24 form a seal against inner wall surface 40 (FIG. 3). The distance 44 between inner wall surface 40 of casing 42 and upper and lower support members 26, 28 is referred to as the extrusion gap 44.

After setting, cantilever element 22 is disposed at angle 36 relative to ramp element 24. Preferably, angle 36 is the equal to, or substantially identical to, angle 34. In other words, as packing element system 20 is moved from its run-in position (FIG. 2) to its set position (FIG. 3) angle 34 does not substantially change. Therefore, if angle 34 at run-in is 48 degrees, angle 36 at setting is substantially equal to 48 degrees. As mentioned above, in a particular preferred embodiment, angle 34 is 50 degrees and, thus, angle 36 is also 50 degrees or substantially equal to 50 degrees. The term “substantially equal” is used herein to mean that the measurement of angle 36 is within 5% of the measurement of angle 34.

As a result of placing cantilever element 22 at angle 34 relative to ramp element 24, a significant portion of the applied axial load used to extrude cantilever element 22 and ramp element 24 is transformed into a radial force because a component of the axial force will be normal to the conical interface 32. This radial force compresses, deforms, or “extrudes” cantilever element 22 and ramp element 24 outward to inner wall surface 40 of casing 42. A seal is then established through outer surface 23 of cantilever element 22 with inner wall surface 40. A seal is also established at interface 32 between cantilever element 22 and ramp element 24, and between mandrel 30 and inner surface 21 of cantilever element 22. Inner surface 25 of ramp element 24 also forms a seal with mandrel 30. The additional axial load not transformed into a radial force squeezes ramp element 24 causing it to bulge or extrude outward and seal against inner wall surface 40 of casing 42. This seal creates a first barrier from wellbore pressure. A second barrier is created by outer surface 23 of cantilever element 22 against inner wall 40 of casing 42. Any extrusion seen in packing element system 20 is experienced in ramp element 24 on the non-sealing end 29, which is the exposed lower surface of ramp element 24. After setting of packing element system 20, angle 36 of interface 32 between cantilever element 22 and ramp element 24 is substantially equal to angle 34 of interface 32 during run-in.

It has been discovered that by placing cantilever element 22 relative to ramp element 24 at angle 34 greater than 45 degrees, and more preferably in the range from 45 degrees to 60 degrees, packing element system 20 provides a seal against inner wall surface 40 of casing 42 without failing at temperatures, pressures, and elapsed time in the ranges equal to prior packing element systems having a back-up component 15 (FIG. 1). For example, in a particularly preferred embodiment in which angle 34 is 50 degrees and axial length 50 of outer surface 23 of cantilever element 22 was longer than axial length 52 of outer surface 27 of ramp 24, a seal was formed along outer surface 23 of cantilever element 22 against inner wall surface 40 of casing 42. This seal held without failing at temperature, pressure, and elapsed time of 325° F., 10,000 PSI, and 17 hours, respectively. Thus, packing element systems 20 constructed in accordance with the teachings herein can obtain the same temperature and pressure ratings as prior packing element systems having a back-up component.

Referring now to FIGS. 4-5, in another embodiment, packing element system 60 comprises mandrel 30 having disposed thereon upper and lower support members 26, 28, upper and lower ramp elements 62, 64 with cantilever element 66 disposed in between upper ramp element 62 and lower ramp element 64. Cantilever element 66, thus, has upper interface 68 and lower interface 70 defining relative to the axis of mandrel 30 upper angle 72 and lower angle 74, respectively. Upper and lower angles 72, 74 are both less than 90 degrees, are both preferably in the range from 40 degrees to 60 degrees, are both more preferably greater than 45 degrees and most preferably 50 degrees. Additionally, although upper angle 72 is not required to be equal to lower angle 74, and vice versa, preferably, upper angle 72 is equal to lower angle 74. Other than the addition of a second ramp element, packing element system 60 operates in the same manner as packing element system 20 shown in FIGS. 2-3 and discussed above.

As shown in FIG. 5, upper and lower angles 72 and 74 remain substantially the same when packing element system 60 is moved from its run-in position (FIG. 4) to its set position (FIG. 5). However, it is to be understood that upper and lower angles 72, 74 do not always stay substantially the same when packing element system 60 is moved from its run-in position (FIG. 4) to its set position (FIG. 5). For example, in some embodiments, upper and lower angles 72, 74 become curved by upper and lower ramp elements 62, 64 wedging under cantilever element 66.

As illustrated in FIGS. 6-7, in another embodiment, packing element system 100 comprises mandrel 130 having disposed thereon upper and lower support members 126, 128, cantilever element 122, and ramp element 124 disposed in between upper and lower support members 126, 128. Upper support member 126 is a top sub sealingly engaged to an upper member 131 of mandrel 130. Thus, upper support member 126 is stationary.

Lower support member 128 is a piston 129 slidingly engaged with mandrel 130. Piston 129 may be any piston known to persons of ordinary skill in the art. As shown in FIGS. 6-7, piston 129 is formed from two members that form chambers between the two members and mandrel 130 so that high and low pressures within the chambers provide the means for movement of piston along mandrel 130.

Like the embodiment shown in FIGS. 2-3, cantilever element 122 and ramp element 124 have interface 132 defining relative to the axis of mandrel 30 angle 34. Angle 34 is less than 90 degrees, preferably in the range from 40 degrees to 60 degrees, more preferably greater than 45 degrees and most preferably 50 degrees. Other than the differing shape of upper supporting member 126 and lower supporting member 128, packing element system 100 operates in the same manner as packing element system 20 shown in FIGS. 2-3 and discussed above.

It is to be understood that the invention is not limited to the exact details of construction, operation, exact materials, or embodiments shown and described, as modifications and equivalents will be apparent to one skilled in the art. For example, in certain embodiments, a stiff ring, not effected by high temperatures and pressures, may be placed between cantilever element 22 and ramp element 24 to facilitate maintaining angle 34 at which cantilever 22 and ramp element 24 are placed in the run-in position (FIG. 2) and, thus, substantially equal to angle 36 at which cantilever element 22 and ramp element 24 interface in the set position (FIG. 1). Additionally, cantilever element 22 may be disposed below ramp element 24 so that cantilever element 22 is adjacent to, and interfaces with, lower cone 28 instead of upper cone 26 (as shown in FIGS. 2-3) and ramp element is adjacent to, and interfaces with, upper cone 26 instead of lower cone 28 (as shown in FIGS. 2-3). Accordingly, the invention is therefore to be limited only by the scope of the appended claims.

Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US7921921Sep 24, 2008Apr 12, 2011Baker Hughes IncorporatedDownhole backup system and method
Classifications
U.S. Classification166/387
International ClassificationE21B33/12
Cooperative ClassificationE21B33/1208
European ClassificationE21B33/12F
Legal Events
DateCodeEventDescription
Apr 5, 2007ASAssignment
Owner name: BAKER HUGHES INCORPORATED, TEXAS
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:VINSON, JUSTIN P.;KROLL, DENNIS E.;BISHOP, DAVID S.;AND OTHERS;REEL/FRAME:019141/0315
Effective date: 20070305