U.S. patent application number 15/313583 was filed with the patent office on 2017-06-29 for drag block assembly.
The applicant listed for this patent is Halliburton Energy Services, Inc.. Invention is credited to David Allen Dockweiler.
Application Number | 20170183921 15/313583 |
Document ID | / |
Family ID | 55264255 |
Filed Date | 2017-06-29 |
United States Patent
Application |
20170183921 |
Kind Code |
A1 |
Dockweiler; David Allen |
June 29, 2017 |
DRAG BLOCK ASSEMBLY
Abstract
Disclosed is a drag block assembly for use with a downhole tool
in a subterranean well, such as packers or bridge plugs. The drag
block assembly comprises a generally cylindrically shaped sleeve
and a block element. The block element is mounted to the sleeve
such that it can radially slide. The block element is outwardly
biased from the sleeve by an electromagnetic element.
Inventors: |
Dockweiler; David Allen;
(McKinney, TX) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Halliburton Energy Services, Inc. |
Houston |
TX |
US |
|
|
Family ID: |
55264255 |
Appl. No.: |
15/313583 |
Filed: |
August 7, 2014 |
PCT Filed: |
August 7, 2014 |
PCT NO: |
PCT/US2014/050084 |
371 Date: |
November 23, 2016 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
E21B 17/1078 20130101;
E21B 33/134 20130101; E21B 33/12 20130101; E21B 33/1291 20130101;
E21B 33/12955 20130101 |
International
Class: |
E21B 17/10 20060101
E21B017/10; E21B 33/12 20060101 E21B033/12 |
Claims
1. A drag block assembly for a downhole tool comprising: a
generally cylindrically shaped sleeve; and a block element mounted
to said sleeve, such that said block element can radially slide,
and wherein said block element is outwardly biased from said sleeve
by an electromagnetic element.
2. The drag block assembly of claim 1, wherein said electromagnetic
element comprises a first magnetic member mounted to said sleeve
and a second magnetic member mounted to said block element, and
wherein said first magnetic member and second magnetic member have
magnetization aligned such that they repel each other.
3. The drag block of claim 2, wherein said first magnetic member
and said second magnetic member have a magnetization sufficient to
provide a spring-like action to said block element and generate a
drag force between said block element and a casing of a wellbore
when said drag block assembly is introduce into said casing.
4. The drag block assembly of claim 1, wherein: said sleeve has an
outer surface, an array of longitudinally disposed slots disposed
around said outer surface, and an inner surface at the bottom of
each slot; said block element has an elongated block-like body with
a casing-wall-contacting outer surface and a bottom surface; and
there are a plurality of said block elements, each said slot has
one of said block elements mounted in said slot such that said
casing-wall-contacting outer surface protrudes through said slot,
and said bottom surface faces said inner surface of said
sleeve.
5. The drag block assembly of claim 4, wherein: said sleeve further
comprises a wall extending from said inner surface to said outer
surface in each slot; and said block has an elastic member
extending around its periphery, such that said elastic member
contacts said wall to block debris from entering into a space
between said inner surface and said bottom surface.
6. The drag block assembly of claim 4, wherein said drag block is
radially moveable within said slot.
7. The drag block assembly of claim 6, wherein said electromagnetic
element comprises a plurality of first magnetic members and a
plurality of second magnetic members, said inner surface of each
said slot has one of said first magnetic members mounted thereto,
said bottom surface of each block element has one of said second
magnetic members mounted thereto, and wherein said first magnetic
member and said second magnetic member have magnetization aligned
such that they repel each other to thus outwardly bias said drag
block element in said slot.
8. The drag block assembly of claim 4, wherein said block element
has a first lateral end having a first flange extending lengthwise
therefrom and a second lateral end having a second flange extending
lengthwise therefrom and wherein said first flange is retained by a
retaining ring disposed about said outer surface of said sleeve and
said second flange being retained by a tab connected to said sleeve
wherein said block is thus mounted in and retained from moving out
of said slot.
9. The drag block assembly of claim 8, wherein said drag block is
radially moveable within said slot.
10. The drag block assembly of claim 9, wherein: said sleeve
further comprises a wall extending from said inner surface to said
outer surface in each slot; and said block has an elastic member
extending around its periphery such that said elastic member
contacts said wall to block debris from entering into a space
between said inner surface and said bottom surface.
11. The drag block assembly of claim 10, wherein said
electromagnetic element comprises a plurality of first magnetic
members and a plurality of second magnetic members, said inner
surface of each said slot has one of said first magnetic members
mounted thereto, said bottom surface of each block element has one
of said second magnetic members mounted thereto, and wherein said
first magnetic member and said second magnetic member have
magnetization aligned such that they repel each other to thus
outwardly bias said drag block element in said slot.
12. The drag block of claim 11, wherein said first magnetic member
and said second magnetic member have a magnetization sufficient to
provide a spring-like action to said block element and generate a
drag force between said block element and a casing of a wellbore
when said drag block assembly is introduce into said casing.
13. A method of centering a downhole tool with drag friction
comprising: (a) connecting a drag block assembly to said downhole
tool, said drag block assembly having a generally cylindrically
shaped sleeve and a plurality of block elements mounted to said
sleeve such that they can radially slide; (b) biasing each said
block element outwardly from said sleeve by an electromagnetic
element; and (c) placing said downhole tool into a casing in a
wellbore such that a casing-wall-contacting outer surface of each
block elements presses outward on the casing thus centering the
downhole tool in the casing and creating drag friction.
14. The method of claim 13, wherein said electromagnetic element
comprises a plurality of first magnetic member mounted to said
sleeve and a plurality of second magnetic member, wherein said
first magnetic members are mounted to said sleeve, each said block
element has one of said second magnetic members mounted thereto,
and said first magnetic member and second magnetic member have
magnetization aligned such that they repel each other.
15. The method of 14, wherein said first magnetic member and said
second magnetic member have a magnetization sufficient to provide a
spring-like action to said block element and generate a drag force
between said block element and said casing when said drag block
assembly is introduce into said casing.
16. The method of claim 15, wherein: said sleeve comprises an outer
surface, an array of longitudinally disposed slots having a bottom
and disposed around said outer surface, and an inner surface at
said bottom of each slot; each said block element comprises an
elongated block-like body with a casing-wall-contacting outer
surface and a bottom surface; and each said slot has one of said
block elements mounted in said slot such that said
casing-wall-contacting outer surface protrudes through said slot,
and said bottom surface faces said inner surface of said
sleeve.
17. The method of claim 16, wherein: said sleeve further comprises
a wall extending from said inner surface to said outer surface in
each slot; and said block has an elastic member extending around
its periphery such that said elastic member contacts said wall to
block debris form entering into a space between said inner surface
and said bottom surface.
18. The method of claim 17, wherein said electromagnetic element
comprises a plurality of first magnetic members and a plurality of
second magnetic members, said inner surface of each said slot
having one of said first magnetic members mounted thereto, said
bottom surface of each said drag block element having one of said
second magnetic members mounted thereto, and wherein said first
magnetic member and said second magnetic member have magnetization
aligned such that they repel each other to thus outwardly bias said
drag block element in said slot.
19. The method of claim 18, wherein said drag block is radially
moveable within said slot.
Description
FIELD
[0001] This disclosure relates to drag block assemblies for use
with downhole tools in subterranean wells, such as packers or
bridge plugs.
BACKGROUND
[0002] In the completion and the production of hydrocarbons from
wells, it is frequently necessary to isolate a portion of the well
using a well tool, such as a packer, plug, tubing hanger and the
like, supported in the wellbore at a subterranean location. These
tools are lowered into the well in a retracted state called the
"run position"; and in a process called "setting", the gripping
means and packing means are radially expanded to a "set position"
wherein the slips means and packing means engage the wellbore. A
variety of types of gripping means are well known in the art, such
as a slip means with wedge-shaped slip elements. Typically, packing
means have resilient annular members mounted on the tool to move
axially to pack off or seal the annulus around the tool. Such
packing means can comprise one or more resilient annular packing
elements which, depending on the use environment, may also comprise
back up and/or anti-extrusion rings. When these packing elements
are axially compressed, they expand radially from the mandrel into
contact with the wellbore. To hold these tools in place in the
wellbore against movement, slip means typically are mounted on the
tool. These slip means, like the packing means, expand radially to
grip the wellbore when forced to compress axially.
[0003] Axially directed forces are used to axially compress the
packing elements and slip assemblies. Such forces are typically
generated by moving the tubing string, initiating an explosive
charge, or applying pressure to the tool. Examples of tools that
are set by manipulating the tubing string include weight down and
tension packers. A weight down packer is one in which force
generated by the weight of the tubing string above the tool is used
to set (expand) the packing and slip element and to hold the tool
in set condition. In a tension packer, the tubing string is placed
in tension and that tension force is used to set and hold the tool
in the set condition.
[0004] Weight down and tension packers typically comprise a hollow
tubular mandrel which is connected to the tubing string. Mounted on
the mandrel are the axially compressible packing elements adjacent
to the slip assembly. An annular tool element called a "drag block
assembly" is located on the mandrel, adjacent the slip assembly on
the opposite side from the packing elements. In weight down tools,
the drag block is located below the slip means. In a tension
packer, the drag block is located above the slip means.
[0005] Drag block assemblies typically frictionally engage the
wellbore. Drag block assemblies are mounted to slide axially on the
mandrel. Drag block assemblies are used to center the tool in the
middle of the casing and to provide a resistant force or frictional
force, which aids in the rotating, setting and unsetting of
downhole tools. This frictional force is also referred to as "drag
friction".
[0006] Conventional prior art packers use drag block having leaf,
bow or compression springs to provide a resistant force pushing the
drag block against the interior surface of the casing thus creating
friction between the drag block and the casing.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] FIG. 1 is a perspective view of a drag block assembly in
accordance with an embodiment.
[0008] FIG. 2 is a perspective view of a drag block element usable
in the drag block assembly of FIG. 1.
[0009] FIG. 3 is a schematic cross-sectional view of a drag block
mounted in the sleeve of the drag block assembly of FIG. 1.
DETAILED DESCRIPTION
[0010] Referring now to the drawings, wherein like reference
numbers are used herein to designate like elements throughout the
various views, various embodiments are illustrated and described.
The figures are not necessarily drawn to scale; and in some
instances, the drawings have been exaggerated and/or simplified in
places for illustrative purposes only. In the following
description, the terms "upper," "upward," "lower," "below,"
"downhole" and the like, as used herein, shall mean: in relation to
the bottom or furthest extent of the surrounding wellbore even
though the well or portions of it may be deviated or horizontal.
The terms "inwardly" and "outwardly" are directions toward and away
from, respectively, the geometric center of a referenced object.
Where components of relatively well-known designs are employed,
their structure and operation will not be described in detail. One
of ordinary skill in the art will appreciate the many possible
applications and variations of the present invention based on the
following description.
[0011] Turning now to FIG. 1, a drag block assembly 10 in
accordance with one embodiment can be seen. Drag block assembly 10
comprises a generally cylindrically shaped sleeve 20 and a block
element 40. Sleeve 20 can be suitable for being received on a
mandrel 12. Mandrel 12 can be attached to a downhole tool at upper
end 14 and/or lower end 16, or mandrel 12 can be part of a mandrel
of a downhole tool. Mandrel 12 has a longitudinal central axis or
longitudinal axial centerline 18. Also, as referred to herein, the
term "radially" will refer to a radial direction perpendicular to
the longitudinal axial centerline 18 and "longitudinal" or "axial"
will refer to a direction parallel to the longitudinal axial
centerline 18.
[0012] Referring now to FIGS. 1 and 3, sleeve 20 has an outer
surface 22, an array of longitudinally disposed slots 24 disposed
around outer surface 22, and an inner surface 26 at the bottom of
each slot 24. A wall 28 extends from inner surface 26 to outer
surface 22 in each slot 24. A first magnet 30 is mounted in inner
surface 26; thus, there are a plurality of magnets disposed about
sleeve 20 in the bottom of slots 24. First magnet 30 can be
embedded within a channel 34 in inner surface 26 such that the
outer surface 32 of first magnet 30 lies flush with inner surface
26. Typically, first magnet 30 will be an elongated magnet having a
length at least 50% of the length of slot 24 and can be at least 70
percent of the length of slot 24. The width of first magnet 30 will
generally be from 80% to 100% of the width of slot 24.
Alternatively, first magnet 30 can be a set of smaller magnets
embedded into inner surface 26, as long as they align with the
magnets in the block element to create a repulsive effect, as
further described below.
[0013] Referring now to FIGS. 1, 2 and 3, a block element 40 is
mounted to sleeve 20 such that it can radially slide. Block element
40 comprises an elongated block-like body 42 with a
casing-wall-contacting outer surface 44 and a bottom surface 46.
Further, a second magnet 48 is mounted in bottom surface 46.
Typically, there are a plurality of block elements 40, such that
each slot 24 has one of block elements 40 mounted in it with
casing-wall-contacting outer surface 44 protruding through the slot
and bottom surface 46 facing inner surface 26 of sleeve 20. Second
magnet 48 is generally mounted flush in bottom surface 46.
Typically, second magnet 48 is approximately the same size and
shape as first magnet 30 and is positioned such that when block
element 40 is mounted in slot 24, first magnet 30 and second magnet
48 will be aligned so as to generate a magnetic repulsion between
the two magnets. Second magnet 48 can be mounted in a channel 49 in
bottom surface 46 such that it is flush with bottom surface 46.
Alternatively, both slot 24 and block element 40 can have several
smaller magnets dispersed about inner surface 26 and bottom surface
46, as long as their positioning and magnetization generate a
repelling force between the inner surface 26 and bottom surface 46.
Also, while described in terms of magnets, other electromagnetic
elements are within the scope of the invention as long as they
produce a repelling electromagnetic force between inner surface 26
and bottom surface 46, such that casing-wall-contacting outer
surface 44 of block element 40 is radially outwardly biased from
sleeve 20 by the electromagnetic elements. If magnets are used,
typically the first magnet and the second magnet can have a
magnetization sufficient to provide a spring-like action to the
block element and generate a drag force between the block element
and a casing of a wellbore when the drag block assembly is
introduce into the casing.
[0014] Block element 40 has a first lateral end 50 and a second
lateral end 52, which extend laterally as opposed to axially or
longitudinally. Block element 40 also has first longitudinal side
54 and second longitudinal side 56, which extend axially or
longitudinally. A first flange 58 extends lengthwise from first
lateral end 50 and a second end flange 60 extends lengthwise from
second lateral end 52. Accordingly, block element 40 can be mounted
within slot 24 by retaining members on sleeve 20 that interact with
flanges 58 and 60 so as to prevent block element 40 from moving out
of slot 24. Thus, first flange 58 can be retained by a retaining
tab 38 connected to sleeve 20, and second flange 60 can be retained
by a retaining ring 36 circumferentially disposed about outer
surface 22 of sleeve 20. When so mounted, block element 40 will be
pushed outward from inner surface 26 by magnetic forces so as to
form a gap 62 between inner surface 26 and bottom surface 46. Gap
62 allows block element 40 to move inward towards inner surface 26
when there is an exterior force on outer surface 44 great enough to
overcome the magnetic force. Moreover, as bottom surface 46 nears
inner surface 26, the magnetic force repelling the two surfaces
will increase requiring greater exterior force to overcome it. When
the exterior force lessens, block element 40 will move outwardly so
as to have a spring-like action.
[0015] For example, a drag block assembly, having a gap 62 of 1
inch when block element 40 is in its outer most position in slot
24, might use two opposing grade N52 magnets having a length of 6
inches, a width of 1 inch and a depth of 1 inch. The magnets for
this drag block assembly will exert approximately 110 lbs with a 1
inch gap with the magnetic field between magnets being about 1,107
gauss and the permeance coefficient being 1.6. As the distance
between the magnets is compressed and approaches contact between
the magnet, the force can increase to approximately 300-400lbs.
[0016] Drag block 40 can have an elastic member extending around
its periphery, such as O-ring 64. When drag block 40 is mounted in
slot 24, O-ring 64 contacts wall 28 to block debris from entering
into gap 62. O-ring 64 is formed from an elastomeric material, such
as Nitrile Butadiene Rubber (NBR). Mandrel 12 and sleeve 20
typically can be formed from a drillable material such as brass or
composite materials such as engineered plastics. Specific plastics
include nylon, phenolic materials and epoxy resins. Drag block
element 40 can also be formed from a composite material or can be
molded from an elastomeric material.
[0017] In operation, a plurality of block elements 40 are mounted
in slots 24 spaced about the periphery of sleeve 20. Drag block
elements 40 are outwardly biased within the slots by an
electromagnetic element, such as magnet pairs 30 and 48. The
resulting drag block assembly is mounted on a mandrel of a downhole
tool. Next, the downhole tool is placed into a casing in a wellbore
such that casing-wall-contacting outer surface 44 of each block
element 40 presses outward on the casing, thus centering the
downhole tool in the casing and creating drag friction. To provide
additional drag force and to limit damage to block element 40, wear
members 66 in the form of buttons or inserts can be mounted on or
in casing-wall-contacting outer surface 44. The wear members can be
formed from tough wear resistant materials, such as composite
materials (hard rubber, resins and the like), metallic materials
(steel, carbide and the like), and ceramic materials.
[0018] In accordance with the above description, there is provided
in one embodiment a drag block assembly for a downhole tool. The
drag block assembly comprises a generally cylindrical shaped sleeve
and a block element. The block element is mounted to the sleeve
such that it can radially slide. The block element is outwardly
biased from the sleeve by an electromagnetic element. The
electromagnetic element can comprise a first magnetic member
mounted to the sleeve and a second magnetic member mounted to the
block element. The first magnetic member and second magnetic member
have magnetization aligned such that they repel each other. The
first magnetic member and the second magnetic member can have a
magnetization sufficient to provide a spring-like action to the
block element and generate a drag force between the block element
and a casing of a wellbore when the drag block assembly is
introduce into the casing.
[0019] In a further aspect, the sleeve can have an outer surface,
an array of longitudinally disposed slots disposed around the outer
surface, and an inner surface at the bottom of each slot. The block
element can have an elongated block-like body with a
casing-wall-contacting outer surface and a bottom surface. There
can be a plurality of the block elements, and each slot has one of
the block elements mounted in it such that the
casing-wall-contacting outer surface protrudes through the slot and
the bottom surface faces the inner surface of the sleeve. The drag
block can be radially moveable in the slot.
[0020] Further, the sleeve can comprise a wall extending from the
inner surface to the outer surface in each slot. The block can have
an elastic member extending around its periphery, such that the
elastic member contacts the wall to block debris from entering into
a space between the inner surface and the bottom surface.
[0021] Additionally, the electromagnetic element comprises a
plurality of first magnetic members and second magnetic members.
Each slot has one of said first magnetic members mounted to the
inner surface thereof. Each block element has one of said second
magnetic members mounted to the bottom surface thereof. The first
magnetic member and the second magnetic member have magnetization
aligned such that they repel each other to thus outwardly bias the
drag block element in the slot.
[0022] In another aspect, the block element can have a first
lateral end having a first flange extending lengthwise therefrom
and a second lateral end having a second flange extending
lengthwise therefrom. The first flange can be retained by a
retaining ring disposed about the outer surface of the sleeve, and
the second flange can be retained by a tab connected to the sleeve.
The block is thus mounted in and retained from moving out of the
slot.
[0023] In another embodiment, there is provided a method of
centering a downhole tool with drag friction. The method comprises:
[0024] (a) connecting a drag block assembly to the downhole tool,
the drag block assembly having a generally cylindrically shaped
sleeve and a plurality of block elements mounted to the sleeve such
that they can radially slide; [0025] (b) biasing each block element
outwardly from the sleeve by an electromagnetic element; and [0026]
(c) placing the downhole tool into a casing in a wellbore such that
a casing-wall-contacting outer surface of each block elements
presses outward on the casing, thus centering the downhole tool in
the casing and creating drag friction.
[0027] In the method, the block elements are radially moveable. The
electromagnetic element can comprise a plurality of first magnetic
members mounted to the sleeve and a plurality of second magnetic
members. Each block element has one of the second magnetic members
mounted to it. The first magnetic member and second magnetic member
have magnetization aligned such that they repel each other. Also,
the sleeve can comprise an outer surface, an array of
longitudinally disposed slots disposed around the outer surface,
and an inner surface at the bottom of each slot. Each block element
can comprise an elongated block-like body with a
casing-wall-contacting outer surface and a bottom surface. Each
slot can have one of the block elements mounted in it such that the
casing-wall-contacting outer surface protrudes through the slot,
and the bottom surface faces the inner surface of the sleeve. The
sleeve can further comprise a wall extending from the inner surface
to the outer surface in each slot. Each block can have an elastic
member extending around its periphery, such that the elastic member
contacts the wall to block debris from entering into a space
between the inner surface and the bottom surface. The drag block
can be radially moveable within the slot.
[0028] While various embodiments of the invention have been shown
and described herein, modifications may be made by one skilled in
the art without departing from the spirit and the teachings of the
invention. The embodiments described here are exemplary only and
are not intended to be limiting. Many variations, combinations, and
modifications of the invention disclosed herein are possible and
are within the scope of the invention. Accordingly, the scope of
protection is not limited by the description set out above, but is
defined by the claims which follow. The scope includes all
equivalents of the subject matter of the claims.
* * * * *