Interventionless Packer Setting Tool

Abstract

A packer setting mechanism has a series of fingers with tabs protruding into the mandrel bore. An object such as a plug is landed on the protruding tabs and pressure is applied. The fingers extend from a ring whose movement triggers the packer to set by driving out slips on cones and compressing a sealing element. When the packer set, tensile stress builds in the fingers and a reduced dimension location on the fingers just above the tabs pulls apart. The plug drives the fingers outwardly by pushing them along a ramp against an opposing spring force. The plug clears the tabs as the tabs are driven outwardly on respective ramps such that the tabs are precluded to enter the bore as the plug clears. The drift dimension in the mandrel is preserved when the plug clears.

Description

FIELD OF THE INVENTION

The field of the invention is packers and more particularly packers that are set with mechanical compression triggered by pressure applied to a landed plug on the setting mechanism with the plug advancing out of the packer after setting.

BACKGROUND OF THE INVENTION

Packers are downhole barriers used in a number of applications to isolate portions of a borehole. They can be set with setting tools that create relative axial movement to axially compress a sealing element and associated slips such that those components extend radially to a sealing position with the slips anchoring the set position of the sealing element. The slips are frequently driven out radially on cones or ramps associated with the mandrel body of the packer. The extended or set position for the packer components can also be locked in with body lock rings or snap rings or dogs in grooves to name a few options. If the packer is to be retrieved, the locking mechanism can be defeated, generally with an upward pull on the packer mandrel through a connected tubular string or by way of a release tool run into the packer on a retrieval string. Some packers can also be released with cutting the mandrel to overcome the locking mechanism. The setting tools that create relative movement generally are of the type that hold a grip on the mandrel while pushing down a setting sleeve to ramp out the slips and axially compress the sealing element to increase its diameter so that a seal is obtained. These relative movement setting tools are driven by developed gas pressure such as by a chemical reaction and are released from the packer as part of the setting movement as a result of parting a retainer that allowed the setting tool to properly position the packer in the borehole.

Other packers can be set with tubing pressure acting on differential piston areas or one side of a piston to achieve axial compression of the assembly of slips, cones and sealing elements to obtain the set position. Another type of packer can hold a caged ball such that pressure from above seats the ball and drives a piston to compress the packer components for a set. The problem with these designs is that the bore through the packer is impeded for flow as the caged ball is displaced off its seat while retained in the cage as produced fluid has to flow around the caged ball. Other tools cannot pass the caged ball, precluding intervention beyond the packer. One example of this design is U.S. Pat. No. 6,394,180. Inflatable packers are set with tubing pressure going through a valving system and into an enclosed volume. Usually one end of the inflatable is free to move and rides up closer to the fixed end as the inflatable grows in radial dimension at a center location for the seal. Still other types of packer are set with reaction to well fluids or their temperature. The sealing element can be a swelling material or a shape memory foam for example.

What is needed and provided by the present invention is a way to set a packer quickly while still leaving the drift diameter of the bore through the packer intact. The setting mechanism is equipped to detain an object on which pressure can be developed to create the compressive force needed to set the packer. As the packer sets components of the setting system separate and retract from the mandrel passage allowing the object to pass leaving the drift dimension intact for operations through the packer. These and other aspects of the present invention will be more readily apparent to those skilled in the art from a review of the detailed description of the preferred embodiment and the associated drawings while recognizing that the full scope of the invention is to be determined form the appended claims.

SUMMARY OF THE INVENTION

A packer setting mechanism has a series of fingers with tabs protruding into the mandrel bore. An object such as a plug is landed on the protruding tabs and pressure is applied. The fingers extend from a ring whose movement triggers the packer to set by driving out slips on cones and compressing a sealing element. When the packer set, tensile stress builds in the fingers and a reduced dimension location on the fingers just above the tabs parts in tension. The plug drives the fingers outwardly by pushing them along a ramp against an opposing spring force. The plug clears the tabs as the tabs are driven outwardly on respective ramps such that the tabs are precluded to enter the bore as the plug clears. The drift dimension in the mandrel is preserved when the plug clears.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of the collet fingers showing the support tabs at the downhole ends;

FIG. 2 is a section view of the packer setting tool before the packer is set;

FIG. 3 is a detailed view of one of the collet fingers showing the preferred parting location;

FIG. 4 is an end view of the collet finger shown in FIG. 3;

FIG. 5 is a close up view in section of the plug landed on the tabs before the packer is set;

FIG. 6 is the view of FIG. 5 with the packer set.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The setting sleeve assembly 10 is slidably mounted over the mandrel 12 such that spaced fingers 14 each having tabs 16 that extend radially into bore 18 of mandrel 12. A pair of wings 20 and 22 straddle longitudinal openings 24 to allow the tabs 16 to extend into bore 18 to serve as support for a setting object such as a plug 26 as shown in FIG. 2. The assembly 10 interacts with a known compression set packer that is not shown. Shoulder 28 is intended to schematically represent an interaction with a setting sleeve of a known packer that is not shown. Movement of the assembly 10 in the direction of arrow 30 under the force of pressure on plug 26 from uphole results in parting at location 32 at the lower end of fingers 14. Assembly 10 initially moves to extend slips and seal of known compression set packer. As contact is made to the surrounding tubular further movement of assembly 10 is arrested and tensile stress begins to build in fingers 14 until the yield limit is reached and separation occurs at necked down location 32 where stress concentrated by design so that the break can occur at that location after the packer sets. With pressure continuing to be applied to the plug 26 that abuts the now unsupported tabs 16 on segments 34 now detached from respective fingers 14 the net result is that the plug 26 advances the segments 34 with great force causing them to each approach a respective ramp 36. Each of the segments has an exterior groove segment 38 such that all the groove segments 38 line up to accept a band spring 40. As the plug 26 causes the break at 32 the segments 34 are accelerated toward ramp 36 and tabs 16 retract radially until the plug 26 can pass. However, the segments 34 have enough momentum to continue to radially expand the spring 40 and to pass the top 42 of the ramp 36. At that point the spring 40 pushes the segments 34 radially toward longitudinal axis 44 until tabs 20 and 22 land on an outer surface of the mandrel 12 at opposed sides of openings 24 and on an opposite side of ramp 36 from the run in position so that the end position of the tabs 16 is such that the drift diameter of bore 18 is not reduced. The packer is now set and the plug 26 can either be caught in a catcher that is not shown, allowed to go to hole bottom or can be allowed to simply disintegrate over time such as when the plug is made of a controlled electrolytic material.

It should be noted that the plug 26 does not need to seal in bore 18 but simply to allow pressure to build behind it to move the assembly 10. The plug can be cylindrical or spherical or other shapes. Once the parted segments run past the ramp they are prevented from going in the reverse direction by the band spring 40 or equivalent designs such as a snap ring, a wedging action, a ratchet locking mechanism or the like. The tabs that supported the plug are retracted far enough to get out of the main mandrel bore so as not to reduce its drift diameter. Although four collet fingers are shown additional or fewer fingers can be used. While the wings 20 and 22 of adjacent fingers are shown spaced apart they can be adjacent to provide nearly continuous support for the band spring 40. The location for the break in the fingers in tension can be accomplished with a reduction in width or thickness or both or by drilling holes or providing a score that extends transversely.

The above description is illustrative of the preferred embodiment and many modifications may be made by those skilled in the art without departing from the invention whose scope is to be determined from the literal and equivalent scope of the claims below:

Claims

1. A subterranean compression set packer setting assembly for a packer comprising a sealing element and at least one slip, comprising:

a mandrel having a passage therethrough, said passage having a drift dimension, said mandrel comprising ends for attachment to a tubular string;

a setting sleeve on said mandrel and extending at least in part through at least one wall opening in said mandrel to present at least one movable support in said passage;

said setting sleeve movable with pressure applied to an object passing through said drift dimension and landed on said support in said passage to set said seal and slip.

2. The assembly of claim 1, wherein:

said support movable in said passage to retract from a central axis of said passage to beyond said drift dimension.

3. The assembly of claim 1, wherein:

said object displaces said support axially.

4. The assembly of claim 1, wherein:

said object displaces said support radially.

5. The assembly of claim 1, wherein:

said at least one support comprises a plurality of supports each extending through a respective said opening.

6. The assembly of claim 5, wherein:

said supports are circumferentially spaced.

7. The assembly of claim 1, wherein:

said setting sleeve comprises a plurality of axially extending fingers at least some of which further comprise a said support adjacent an end thereof

8. The assembly of claim 7, wherein:

said supports separating from said associated fingers to create segments on rising tensile stress in said associated fingers resulting from force transfer from said object to said supports when further movement of said sleeve is impeded by setting the slip and seal of the packer.

9. The assembly of claim 7, wherein:

said fingers mounted outside said mandrel with said supports extending through respective said openings, said supports further comprise opposed wings to limit travel of said support toward a center of said passage.

10. The assembly of claim 9, wherein:

said mandrel comprises at least one ramp to engage at least one of said wings to retract said supports outside said drift dimension.

11. The assembly of claim 8, wherein:

said fingers comprising a feature to concentrate tensile stress to define a separation location for said segments.

12. The assembly of claim 11, wherein:

said concentrating tensile stress feature comprises at least one of a score, openings, reduced dimension and slots.

13. The assembly of claim 11, wherein:

said segments are radially biased toward an axis of said passage.

14. The assembly of claim 13, wherein:

said bias comprises a band spring.

15. The assembly of claim 13, wherein:

said object pushes said segments on a ramp to retract said segments to allow said object to pass;

said radial bias on said segments biasing said segments toward the axis of said passage after said segments clear said ramp such that said segments are positioned outside said drift dimension.

16. The assembly of claim 15, wherein:

said ramp configured to preclude return movement of said segments after initial movement over said ramp.

17. The assembly of claim 1, wherein:

said object does not seal pressure when landed on said support.

18. The assembly of claim 7, wherein:

said fingers extend from a base ring whose movement sets the seal and slip of the packer.

19. The assembly of claim 15, wherein:

said fingers mounted outside said mandrel with said supports extending through respective said openings, said supports further comprise opposed wings to limit travel of said support toward a center of said passage.