WO2009050503A2

WO2009050503A2 - Anchoring device

Info

Publication number: WO2009050503A2
Application number: PCT/GB2008/050918
Authority: WO
Inventors: David Martin
Original assignee: Caledyne Ltd
Current assignee: Caledyne Ltd
Priority date: 2007-10-18
Filing date: 2008-10-07
Publication date: 2009-04-23
Anticipated expiration: 2010-04-18
Also published as: WO2009050503A3

Abstract

An anchoring device for anchoring a movable body to a stationary surface, the anchoring device comprising: at least one cam member which is movable in a first direction substantially parallel to the longitudinal axis of the movable body, the cam member having a cam surface which is at an oblique orientation to the first direction; a grip member having gripping means for preventing movement of the movable body relative to the stationary surface, and having a first oblique surface; and at least one intermediary member have a second oblique surface which cooperates with the cam surface of the cam member and a third oblique surface which cooperates with the first oblique surface of the grip member such that movement of the cam member in the first direction causes at least movement of the intermediary member in a second direction normal to the first direction which in turn causes movement of the grip member in the second direction such that the gripping means engages with the stationary surface.

Description

Anchoring Device

This invention relates to an anchoring device particularly, but not exclusively, for down-hole tools. In particular, the device may comprise expansion cones, slips and intermediate expander segments.

Anchor systems are well known in the oil and gas industry and are used to locate down-hole tools within the well tubing string. Various slip and cone systems are in existence, where the cones or expanders are moved to urge the slip sections outwards from the tool body to engage with the inside of the well tubing string. Once engaged with the tubing wall, axial forces applied to the down- hole tool via mechanical or hydraulic forces are transmitted to the tubing wall via the cone and slip system.

One main limitation of the majority of the slip and cone designs is that the percentage expansion, i.e. the reach of the slips from the major outside diameter or gauge diameter of the down-hole tool to the inside wall of the well tubing string is limited by the wall section of the cone and slip. So to increase the reach of the slips, the diameters of the mounting mandrel or tube have to be reduced. In through-tubing applications for down-hole tools, the reach of the anchor has to be significantly larger than on standard down-hole tools. This is because the down- hole tool has to pass through a restriction, such as a tubing patch or smaller diameter tubing. The slip expansion ratio must then be higher to reach the inside wall of the well tubing string.

Various solutions have been arrived at for high expansion anchor systems, in particular as described in US patent applications, High Expansion Anchor System 2004031606 (Xu Yang) and Extended Reach Anchor 2007175631 (O'Brien) .

As noted in the patent application 2004031606 High Expansion Anchor System, the design is limited in that the expectation is that the pins mentioned may fail due to mechanical loading. This type of anchor system is useful for locating monitoring devices such as pressure sensors, but is of limited use on packers and plugs, where significant loads are generated by differential pressure across the down-hole tool.

As noted in the illustration for the Extended Reach Anchor, the through bore of the tool is small in comparison with the major diameter of the tool.

An anchoring device is described which overcomes or mitigates the problems encountered in the current state of the art. This anchoring device would normally be part of a larger assembly, typically a well packer, bridge plug or gauge hanger. Methods for moving the cones to activate the mechanism and to hold the cones in such a position as to maintain the anchor to the well tubing string are understood and commercially available.

According to the present invention there is provided an anchoring device for anchoring a movable body to a stationary surface, the anchoring device comprising: at least one cam member which is movable in a first direction substantially parallel to the longitudinal axis of the movable body, the cam member having a cam surface which is at an oblique orientation to the first direction; a grip member having gripping means for preventing movement of the movable body relative to the stationary surface, and having a first oblique surface; and at least one intermediary member have a second oblique surface which cooperates with the cam surface of the cam member and a third oblique surface which cooperates with the first oblique surface of the grip member such that movement of the cam member in the first direction causes at least movement of the intermediary member in a second direction normal to the first direction which in turn causes movement of the grip member in the second direction such that the gripping means engages with the stationary surface. Preferably the anchoring device is connected to a downhole tool for anchoring the tool to well tubing.

The anchoring device may use a plurality of intermediary members to increase the overall expansion ratio of the anchoring component of tool, to the gauge diameter of the down-hole tool, in relation to the inside diameter of the well tubing string.

The grip member may be fixed to the intermediary member by a releasable connector. The releasable connector may be adapted to release the connection of the grip member and the intermediary member when a predetermined value of a parameter is reached. Preferably the parameter comprises a breaking force and the releasable connector breaks when a sufficiently high breaking force is reached. Preferably the releasable connector is a shearable connector. Alternatively or in addition, the parameter may be movement of one or both of the grip member and the intermediary member in a direction.

A plurality of intermediary members may be provided between the cam member and the grip member.

Preferably the anchoring device comprises two cam members, a central grip member and two intermediary members and movement of the cam members towards each other causes movement of each intermediary member in the second direction which in turn causes movement of the grip member in the second direction such that the gripping means engages with the stationary surface.

The intermediary member may have a limited travel, to prevent the intermediary member becoming disengaged from the cam member.

The grip member may have a limited travel, to prevent the grip member becoming disengaged from the intermediary member.

Preferably the grip member and intermediary member have further features, which prevent each component becoming detached from the other.

Preferably one or more of the cam member, intermediary member and grip member include guide means which allows only movement parallel to the oblique surfaces. The components may be mechanically linked via tee-slots or a similar arrangement. The formation of the slots and tee sections on the mating parts may be so designed to expand the expander segments and slips when one, or other or both cones are moved axially towards each other.

Preferably the anchoring device is arranged so that movement of the cam member in a third direction opposite to the first direction to disengage the grip member from the stationary surface. When the anchoring device is used for a downhole tool, this allows the down-hole tool to be removed from the well tubing string.

In a downhole application , axial loads imparted to the down-hole tool, by application of differential pressure across a packer seal or by a mechanical load may be transferred to the well tubing string by compressive forces acting through the cone, expander segment, slip and the engagement of teeth on the outside surface of the slip with the inside wall.

Preferably the gripping means is configured to provide a biting action, but fundamentally produces a friction force with the stationary surface.

A particular embodiment of the invention will now be described by way of example only with reference to the accompanying drawings in which:

Figure 1 shows a cross section view of the anchoring device in the collapsed position, for installation of a down-hole tool in a well tubing string.

Figure 2 shows a cross section view of the anchoring device in the partially set position, with the expander segments expanded and slips pinned to the expander segments . Figure 3 shows a cross section view of the anchoring device in the fully set position, with the slips engaged with the inside wall of the well tubing string.

Figures 4 and 5 show isometric views of the staged assembly of the anchoring device.

Figures 6 and 7 show detailed views of the components within the anchoring device.

In the preferred embodiment of the invention, as shown in figure 1, the anchoring device is deployed in a well tubing string 1 having a stationary surface. The anchoring device comprises a mandrel 2, a first cam member or upper cone 3A, two intermediary members or expander segments 4A, a grip member or slip 5A, shearable members 6A and a second cam member or lower cone 7A.

This system may be part of a larger assembly such as a well packer, bridge plug or other such anchor assemblies.

As shown in figure 2, the anchoring device is operated by manipulation of the cone sections 3B and 7B. By moving the cones towards one another the angled surfaces on the cones 3B and 7B contact the matching surfaces on the expander segments 4B, urging the said segments outwards. As shown in figure 6B, feature 11 on expander segment 4 acts as a stop, limiting the movement of the expander segment. The slips 5B are prevented from moving by shearable members, preferably shear screws 6A. When the expander segments 4B reach the end of their travel, the setting load is transmitted to the shearable members 6A, which in turn shear, allowing the slips 5B to expand. The matching faces between the expander segments 4C and slips 5C urge the slips to move out and contact the inside wall of the well tubing string 1.

Figure 3 shows the anchoring device engaged with the inside wall of the well tubing string 1. The cones 3C and 7C have fully expanded the mechanism. Expander segments 4C support the slips 5C against the well tubing string 1.

With reference to details on figures 6A, 6B and 7, figures 4 and 5 show the staged assembly of the anchor to clarify the operation of the guide means or tee-slots. On cones 3 and 7 angled slots 8 are profiled such that they form a tee slot. The internal tee slot 12 on expander segment 4 engages with the slot 8 on cones 3 and 7. Similarly, the external tee slot 10 on the expander segment 4 engages with the profile 14 on the slip 5. When the anchoring device is expanded, compressive loads are transmitted via the flats 16 on the cones 3 and 7 to mating surface on the expander segment 4. In turn the load is transferred via face 9 on the expander segment 4 to face 15 on the slip. A toothed profile 13 is used to engage the slips with the well tubing string 1, where the said teeth bite into the tubing wall, anchoring the tool in place. Various modifications and variations can be made without departing from the scope of the present invention.

Claims

1. An anchoring device for anchoring a movable body to a stationary surface, the anchoring device comprising: at least one cam member which is movable in a first direction substantially parallel to the longitudinal axis of the movable body, the cam member having a cam surface which is at an oblique orientation to the first direction; a grip member having gripping means for preventing movement of the movable body relative to the stationary surface, and having a first oblique surface; and at least one intermediary member have a second oblique surface which cooperates with the cam surface of the cam member and a third oblique surface which cooperates with the first oblique surface of the grip member such that movement of the cam member in the first direction causes at least movement of the intermediary member in a second direction normal to the first direction which in turn causes movement of the grip member in the second direction such that the gripping means engages with the stationary surface.

2. An anchoring device as claimed in Claim 1, wherein the anchoring device is connected to a downhole tool for anchoring the tool to well tubing.

3. An anchoring device as claimed in Claim 2, including a plurality of intermediary members to increase the overall expansion ratio of the tool to the inside diameter of the well tubing string.

4. An anchoring device as claimed in any preceding claim, wherein the grip member is fixed to the intermediary member by a releasable connector.

5. An anchoring device as claimed in Claim 4, wherein the releasable connector is adapted to release the connection of the grip member and the intermediary member when a predetermined value of a parameter is reached.

6. An anchoring device as claimed in Claim 5, wherein the parameter comprises a breaking force such that the releasable connector breaks when a sufficiently high breaking force is reached.

7. An anchoring device as claimed in any of claims 4 to 6, wherein the releasable connector is a shearable connector.

8. An anchoring device as claimed in Claim 5 or 6, wherein the parameter comprises movement of one or both of the grip member and the intermediary member in a direction.

9. An anchoring device as claimed in any preceding claim, wherein a plurality of intermediary members is provided between the cam member and the grip member.

10. An anchoring device as claimed in any preceding claim, including two cam members, a central grip member and two intermediary members, and wherein movement of the cam members towards each other causes movement of each intermediary member in the second direction which in turn causes movement of the grip member in the second direction such that the gripping means engages with the stationary surface.

11. An anchoring device as claimed in any preceding claim, wherein one or more of the cam member, intermediary member and grip member include guide means which allows only movement substantially parallel to the oblique surfaces.

12. An anchoring device as claimed in any preceding claim, wherein one or more of the cam member, intermediary member and grip member are mechanically linked via one or more tee-slots.

13. An anchoring device as claimed in any preceding claim, wherein the anchoring device is arranged so that movement of the cam member in a third direction opposite to the first direction causes the grip member to disengage from the stationary surface.

14. An anchoring device as claimed in any preceding claim, wherein the gripping means is configured to produce a friction force with the stationary surface.

15. An anchoring device substantially as hereinbefore described and illustrated in the accompanying drawings.

16. A downhole tool substantially as hereinbefore described and illustrated in the accompanying drawings.