U.S. patent application number 14/283947 was filed with the patent office on 2014-09-11 for rolled tubular centralizer.
This patent application is currently assigned to Antelope Oil Tool & Mfg. Co., LLC. The applicant listed for this patent is Antelope Oil Tool & Mfg. Co., LLC. Invention is credited to Jean Buytaert, Jeffrey Kubiak, Clayton Plucheck.
Application Number | 20140251595 14/283947 |
Document ID | / |
Family ID | 50431806 |
Filed Date | 2014-09-11 |
United States Patent
Application |
20140251595 |
Kind Code |
A1 |
Buytaert; Jean ; et
al. |
September 11, 2014 |
ROLLED TUBULAR CENTRALIZER
Abstract
A method of forming a centralizer where a flat plate is created
into a tubular where the flat plate is typically rolled so that two
sides of the plate contact one another and are then linked,
typically by welding. Openings are then created in the tubular such
that there are no corners or other points that stress cracks may
originate. Once the openings are created the remaining material
between adjacent openings forms ribs. The openings created in the
tubular are generally aligned with the long axis of the tubular.
The material at the upper and lower end of the flat plate where
openings were not created serve as circumferential collars. The
ribs may be radially outwardly expanded in order to provide
adequate stand-off. In many instances the ribs will also be
hardened by heat treating or other hardening processes.
Inventors: |
Buytaert; Jean; (Mineral
Wells, TX) ; Plucheck; Clayton; (Tomball, TX)
; Kubiak; Jeffrey; (Houston, TX) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Antelope Oil Tool & Mfg. Co., LLC |
Mineral Wells |
TX |
US |
|
|
Assignee: |
Antelope Oil Tool & Mfg. Co.,
LLC
Mineral Wells
TX
|
Family ID: |
50431806 |
Appl. No.: |
14/283947 |
Filed: |
May 21, 2014 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
13957016 |
Aug 1, 2013 |
|
|
|
14283947 |
|
|
|
|
13191074 |
Jul 26, 2011 |
|
|
|
13957016 |
|
|
|
|
Current U.S.
Class: |
166/241.1 ;
29/428 |
Current CPC
Class: |
E21B 17/1028 20130101;
E21B 17/1078 20130101; E21B 19/24 20130101; Y10T 29/49826 20150115;
Y10T 156/1038 20150115 |
Class at
Publication: |
166/241.1 ;
29/428 |
International
Class: |
E21B 19/24 20060101
E21B019/24 |
Claims
1. A method for manufacturing a centralizer, comprising: rolling a
plate such that first and second sides of the plate are adjacent;
attaching together the first and second sides, such that a seam is
formed where the first and second sides are attached together; and
after rolling the plate, removing one or more portions from the
plate, such that two or more ribs are defined extending between two
or more end collars.
2. The method of claim 1, wherein removing the one or more portions
of the plate occurs after attaching together the first and second
sides.
3. The method of claim 1, wherein removing the one or more portions
comprises removing at least a portion of the seam.
4. The method of claim 1, wherein removing the one or more portions
comprises forming one or more openings that do not intersect the
seam.
5. The method of claim 1, wherein removing the one or more portions
comprises forming one or more openings that extend substantially
parallel to the seam.
6. The method of claim 5, wherein the seam is defined along one of
the two or more ribs.
7. The method of claim 1, wherein removing the one or more portions
comprises forming two or more openings between which the two or
more ribs are defined, the two or more openings being substantially
oval-shaped.
8. The method of claim 1, wherein the seam comprises a non-linear
shape selected from the group consisting of: one or more smooth
curves, one or more jagged curves, or one or more zig-zag
shapes.
9. The method of claim 1, wherein attaching together the first and
second sides comprises welding the first and second sides together,
without overlapping.
10. The method of claim 1, wherein: rolling the plate comprises
spiral winding the plate; the seam extends along a helical path;
and removing the one or more portions comprises forming one or more
openings that intersect the seam at least once.
11. The method of claim 1, wherein: the plate comprises a first
plate segment and a second plate segment, the first plate segment
providing the first side and the second plate segment providing the
second side; and rolling the plate comprises forming each of the
first and second plate segments into an arcuate shape.
12. A centralizer, comprising: a tubular body comprising a first
side and a second side, the first and second sides extending
axially along the tubular body, wherein the tubular body defines at
least first and second axially-offset end collars and a plurality
of ribs extending between the first and second end collars, the
plurality of ribs being integral with the first and second end
collars; and a seam connecting the first side and the second side
together, wherein the seam is formed along at least a portion of
the first end collar and along at least a portion of the second end
collar, such that the first and second sides are connected together
to form the first and second end collars without overlapping the
first and second sides.
13. The centralizer of claim 12, wherein the seam is
circumferentially aligned with an opening defined between two of
the plurality of ribs.
14. The centralizer of claim 12, wherein the seam extends parallel
to and along an entirety of at least one of the plurality of
ribs.
15. The centralizer of claim 12, wherein the plurality of ribs are
elongated in an axial direction, and wherein the seam extends at a
non-zero angle to the axial direction and is defined on at least
one of the plurality of ribs.
16. The centralizer of claim 15, wherein the seam is defined on at
least two of the plurality of ribs.
17. The centralizer of claim 15, wherein the seam extends in a
partial helix along the body.
18. The centralizer of claim 12, wherein the first and second sides
each define one or more curves.
19. The centralizer of claim 12, wherein the first and second sides
are connected end-to-end without overlap.
20. The centralizer of claim 12, wherein the tubular body further
comprises third and fourth sides, and the centralizer further
comprises a second seam connecting together the third and fourth
sides.
21. A centralizer, comprising: a first end collar comprising a
first seam portion extending axially across the first end collar; a
second end collar that is axially offset from the first end collar
and comprises a second seam portion extending axially across the
second end collar; and a plurality of ribs extending between the
first and second end collars and being integral therewith, at least
one of the plurality of ribs comprising a third seam portion.
22. The centralizer of claim 21, wherein the first end collar and
the second end collar are free from overlapping regions.
23. The centralizer of claim 21, wherein the first and second seam
portions are circumferentially aligned.
24. The centralizer of claim 21, wherein the first, second, and
third seam portions form a continuous seam.
25. The centralizer of claim 21, wherein the plurality of ribs are
elongated in an axial direction, and wherein the third seam portion
extends at a non-zero angle with respect to the axial
direction.
26. The centralizer of claim 25, wherein the first, second, and
third seam portions together extend along a helical path.
27. The centralizer of claim 21, wherein at least two of the
plurality of ribs define the third seam portion.
28. A method for manufacturing a centralizer, comprising: rolling a
substantially linear plate such that first and second sides of the
plate are adjacent; attaching together the first and second sides,
such that a first seam portion, a second seam portion and a third
seam portion are formed; and removing one or more portions from the
plate, such that two or more ribs are defined extending between two
end collars.
29. The method of claim 28, wherein the first, second, and third
seam portions form a continuous seam
30. The method of claim 28, wherein the two end collars include the
first and second seam portions, respectively.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is a continuation of to U.S. patent
application Ser. No. 13/957,016, filed on Aug. 1, 2013, which is a
continuation-in-part of U.S. patent application Ser. No.
13/191,074, filed on Jul. 26, 2011. The entirety of both of these
applications is incorporated herein by reference.
FIELD OF INVENTION
[0002] Embodiments of the present invention generally relate to
methods and apparatuses a downhole operation. More particularly,
the invention relates to methods and apparatuses for centralization
in wellbores or tubulars.
BACKGROUND
[0003] In the course of drilling and producing oil and gas wells,
it has been found be beneficial to keep the tubular, which may be
drill pipe, casing, production pipe, or screens, generally centered
in the well. In certain instances it may be desirable to center one
tubular within another. By keeping the tubular generally centered
in the well a substantially uniform annular area between the
wellbore wall and the tubular is maintained. In certain instances,
such as cementing the tubular into the well, centralization to
provide a substantially uniform annular area is imperative. By
having a substantially uniform annular area the cement is better
able to fill all voids between the tubular and the well thereby
forming a better bond with both the wellbore wall and the
tubular.
[0004] A common type of centralizer is a bow spring centralizer. A
bow spring centralizer typically includes a number of bows attached
to a collar on the upper end of the bow and on the lower end of the
bow. The bow typically curves radially outward between the two
collars. In its simplest form the bow spring centralizer slides
over a tubular joint and is restricted only by the tubular
couplings at either end of the tubular joint. In some situations,
when the bow spring centralizer is pushed into a wellbore on a
tubular string the leading collar may be stopped by a restriction
that will cause the bows to longitudinally compress thereby
radially expanding the bows radially outwards ultimately causing
the bow to fail as the tubular string continues to move down into
the well. The problem is compounded due to the thickness of the bow
spring centralizer's collars and ribs. Usually the collars and the
ribs had the same thickness however the thickness of the
centralizer as a whole centralizer was effectively doubled because
the ribs were welded on top of the collar. In the event that a rib
was welded edge to edge to the collar a generally weaker collar to
rib interface is created and stress points are created by both the
welding process and the remaining corners or other sharp
points.
[0005] One solution has been to attach at least one of the collars
of the bow spring centralizer so that the centralizer will be
pulled into the wellbore rather than pushed into the wellbore.
SUMMARY
[0006] In order to minimize any potential stress points created by
either welding or by having any sharp points or corners, it was
envisioned that a centralizer is fabricated wherein a planar
material having an upper end, a lower end, a first side, and a
second side is formed into a tubular such that the planar material
first side contacts the planar material second side. The planar
material first side may be linked with the planar material second
side. An elongated opening is then created in the tubular. The
tubular has a long axis and the opening has a long axis having a
first end and a second end such that the opening first end is
adjacent the planar material upper end and the opening second end
is adjacent the planar material lower end. Typically the opening
does not have any corners and may be an oval, or a rectangle.
Preferably the rectangle has rounded corners. In most instances the
opening long axis is parallel to the long axis of the tubular
although in some cases the opening long axis is not parallel to the
long axis of the tubular. Typically the planar material first side
is linked to the planar material second side by welding.
[0007] In another embodiment of fabricating a centralizer, a planar
material having an upper end, a lower end, a first side, and a
second side may be formed into a tubular such that the planar
material first side contacts the planar material second side. The
planar material first side is linked with the planar material
second side. A number of elongated openings are then created in the
tubular. The tubular has a long axis and each of the plurality of
openings has a long axis having a first end and a second end such
that the opening first end is adjacent the planar material upper
end and the opening second end is adjacent the planar material
lower end. While usually the planar material is rolled into a
cylinder where the rolling is parallel to one side in some
instances the planar material may be rolled into a cylinder by
spiral winding process where the rolling is not parallel to either
side. In such instances a long tubular may be formed without
stopping. Typically the plurality of openings do not have corners.
While usually the plurality of openings are ovals the openings may
be rectangles although in most instances the rectangles have
rounded corners. Typically the plurality of openings long axis are
parallel to the long axis of the tubular although in some cases the
plurality of openings long axis are not parallel to the long axis
of the tubular. Usually the planar material first side is linked to
the planar material second side by welding. In most instances the
openings are created within the tubular structure that was formed
from the planar material. The material in the tubular structure
both above and below the openings define circumferential collars.
The material in the tubular structure between the openings define
ribs that are disposed between the upper collar and lower collar.
Typically the ribs are expanded radially outward where the
expansion process typically, but not always, plastically deforms
the ribs. Typically the ribs and in many instances the entire
centralizer may be heat-treated, hardened, cured, or any other
process known to one skilled in the art to allow the ribs to
elastically deflect after the ribs are expanded. However, in
certain instances the ribs or the entire centralizer may be
heat-treated, hardened, cured, or any other process known to one
skilled in the art.
[0008] In another embodiment of fabricating a centralizer a first
planar material having an upper end and a lower end, a first side,
and a second side and at least a second planar material having an
upper end, a lower end, a first side, and a second side may be
formed into a tubular such that the first planar material first
side contacts second planar material second side and the first
planar material second side contacts the at least second planar
material first side. The first planar material first side may be
linked with the at least second planar material second side and the
first planar material second side may be linked with the second
planar material first side. A number of elongated openings are then
created in the tubular. The tubular has a long axis and each of the
plurality of openings has a long axis having a first end and a
second end such that the opening first end is adjacent the planar
material upper end and the opening second end is adjacent the
planar material lower end. While usually the planar material is
rolled into a cylinder where the rolling is parallel to one side in
some instances the planar material may be rolled into a cylinder by
spiral winding process where the rolling is not parallel to either
side. In such instances a long tubular may be formed without
stopping. Typically the plurality of openings do not have corners.
While usually the plurality of openings are ovals the openings may
be rectangles although in most instances the rectangles have
rounded corners. Typically the plurality of openings long axis are
parallel to the long axis of the tubular although in some cases the
plurality of openings long axis are not parallel to the long axis
of the tubular. Usually the planar material first side is linked to
the planar material second side by welding. In most instances the
openings are created within the tubular structure that was formed
from the planar material. The material in the tubular structure
both above and below the openings define circumferential collars.
The material in the tubular structure between the openings define
ribs that are disposed between the upper collar and lower collar.
Typically the ribs are expanded radially outward where the
expansion process typically, but not always, plastically deforms
the ribs. The ribs may be heat-treated, hardened, cured, or any
other process known to one skilled in the art before or after the
expansion or forming of the ribs.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] So that the manner in which the above recited features of
the present invention can be understood in detail, a more
particular description of the invention, briefly summarized above,
may be had by reference to embodiments, some of which are
illustrated in the appended drawings. It is to be noted, however,
that the appended drawings illustrate only typical embodiments of
this invention and are therefore not to be considered limiting of
its scope, for the invention may admit to other equally effective
embodiments.
[0010] FIG. 1 depicts a generally flat material.
[0011] FIG. 2 depicts the generally flat material rolled into a
tubular.
[0012] FIG. 3 depicts a first and a second generally flat material
each formed into a portion of the tubular.
[0013] FIG. 4 depicts the first and the second generally flat piece
of material each formed into a portion of the tube of FIG. 3 linked
together.
[0014] FIG. 5 depicts a generally flat piece of material having a
length substantially greater than its width.
[0015] FIG. 6 depicts the generally flat piece of material of FIG.
5 formed into a tubular by spiral winding.
[0016] FIG. 7 depicts a generally flat piece of material having a
nonlinear first side and a mirrored nonlinear second side.
[0017] FIG. 8 depicts the generally flat piece of material of FIG.
7 rolled into a tubular so that the nonlinear first side and
mirrored nonlinear second side mate together.
[0018] FIG. 9 depicts a rolled tubular with openings created
therein that are parallel to the long axis of the tubular.
[0019] FIG. 10 depicts a rolled tubular with openings created
therein that are not parallel to the long axis of the tubular.
[0020] FIG. 11 depicts a rolled tubular where the first side and
second side are partially linked.
[0021] FIG. 12 depicts the rolled tubular of FIG. 11 where at least
one opening is created across the unlinked portions between the
first side and second side.
[0022] FIG. 13 depicts a rolled tubular having ribs that have been
radially expanded.
DETAILED DESCRIPTION
[0023] The description that follows includes exemplary apparatus,
methods, techniques, and instruction sequences that embody
techniques of the inventive subject matter.
[0024] FIG. 1 depicts a generally flat material 10 having an upper
end 12, a lower end 14, a first side 18 and a second side 16.
Typically the process of forming a tubular begins with the
generally flat material 10 where the generally flat material 10
does not have any openings or notches in the material. When forming
the generally flat material 10 into the tubular, the generally flat
material 10 may be rolled by a plate roll, may be hydraulically
formed, hydro-dynamically formed, stamped, or any other process
known for forming flat material into a roll. While it is
anticipated that the generally flat material 10 will typically be a
steel or other ferrous material, any material may be used including
most metals, plastics, or fiber reinforced materials such as carbon
fiber polymers and epoxies.
[0025] FIG. 2 depicts the generally flat material 10 from FIG. 1
after the generally flat material 10 has been rolled into a tubular
20 so that the first side 18 and the second side 16 are in contact
with one another along their length. With the first side 18 in the
second side 16 in contact with one another the sides 16 and 18 may
be linked. In some instances the sides 16 and 18 may be linked one
to the other by welding, crimping, pinning, gluing, epoxy or any
other linking process known in the industry.
[0026] In some instances multiple generally flat materials may each
be partially formed into a tubular such that when their sides come
into contact with one another and are linked to multiple generally
flat materials will form the tubular. FIG. 3 depicts a first curved
piece of material 30 and a second curved piece of material 40 that
were formed from two pieces of generally flat material. In this
instance, the first curved piece of material 30 has an upper end
32, a lower end 34, a first side 36, and a second side 38. The
second curved piece of material 40 has an upper end 42, a lower end
44, a first side 46, and the second side 48.
[0027] FIG. 4 depicts the curved pieces of material 30 and 40
respectively that have been aligned such that the first side 36 of
the first curved piece of material 30 and the second side 48 of the
second curved piece of material 40 are in contact with one another
along their length while the second side 38 of the first curved
piece of material 30 and the first side 46 of the second curved
piece of material 40 are also in contact with one another along
their length. With the first curved piece of material 30 and the
second curved piece of material 40 in contact with one another, the
curved pieces of material may be linked together to form a tubular
50.
[0028] In other instances a generally flat material may be spiral
wound such that its first side and the second side come into
contact with one another. FIG. 5 depicts an elongated piece of
generally flat material 60 where a length 63 is substantially
greater than a width 61. The generally flat material 60 has an
upper end 62, a lower end 68, a first side 64, and the second side
66. As depicted in FIG. 6, the generally flat material 60 has been
formed into a tubular 70. The generally flat material 60 was rolled
or otherwise formed into the tubular 70 at an angle that was not
parallel to the upper end 62, the lower end 68, the first side 64,
or the second side 66. The tubular 70 may be curved by a spiral
winding process such that the first side 64 and the second side 66
may be linked to one another.
[0029] In certain instances, as depicted in FIG. 7, a generally
flat material 80 has an upper end 82, a lower end 84, a first side
88, and a second side 86 where the first side 88 and the second
side 86 are nonlinear reflections of one another. FIG. 8 depicts
the generally flat material 80 from FIG. 7 after the generally flat
material 80 has been formed into a tubular 90 so that the first
side 88 and the second side 86 are in contact with one another
along their length. With the first side 88 in the second side 86 in
contact with one another the two sides 86 and 88 may be linked to
form a nonlinear seam between the sides 86 and 88. In those
instances where the sides 86 and 88 are nonlinear reflections of
one another the two sides may take any form such as a smooth curve,
a jagged curve, zig-zags, or any other form.
[0030] FIG. 9 depicts the tubular 20 of FIG. 2 where the first and
the second sides 16 and 18 are linked together and with openings
102 created through the tubular 20. Generally the long axis of the
tubular 20 is parallel to the seam created by linking first and
second sides 16 and 18 although in some cases such as when the
tubular is formed by spiral winding the seam will not be parallel
to the long axis of the tubular. Each opening 102 has an upper end
104, a lower end 106, and a long axis 108 where the long axis 108
is generally parallel to the long axis of the tubular 20. Ribs 112
are created by the material of the tubular 20 that remains between
the openings 102 after the openings 102 are created in the tubular
20. A first collar 114 and a second collar 116 are created by the
material of the tubular 20 that remains above the upper end 104 of
the openings 102 and below the lower end 106 of the openings 102
after the openings 102 are created in the tubular 20. To prevent
failure in the ribs 112 as the ribs 112 are being moved downhole,
the ribs 112 are created from the tubular 20 thereby eliminating
the potential stress point such as when the ribs in the prior art
are welded onto their collars. Additionally the openings 102 are
created preferably as ovals to minimize stress points in the ribs
112 that may remain after the openings 102 are created in the
tubular 20 although any shape that avoids sharp corners or points
may be used. The openings 122 may be formed through the tubular 50,
70, and 90 in a similar manner.
[0031] In certain instances such as when the material used to form
the tubular is thick enough or is not hardened, heat treated, or
cured to obtain spring-like properties, each rib 112 will have the
ability to plastically deform when subjected to sufficient side
load. In such cases, the centralizer will act like a rigid type
centralizer that has the ability to give when inserted through a
tight restriction. When the material is not as thick as in the case
of a rigid centralizer described above and when the material is
heat treated, hardened, or cured to provide spring-like properties,
each rib 112 will have spring-like properties and the centralizer
will act as a bow type centralizer.
[0032] FIG. 10 depicts a tubular 120 having an upper end 121, a
lower end 123, and openings 122 created through the tubular 120.
Each opening 122 has an upper end 124, a lower end 126, and a long
axis 128 where the long axis 128 is generally not parallel to the
long axis of the tubular 120. Ribs 132 are created by the material
of the tubular 120 that remains between the openings 122 after the
openings 122 are created in the tubular 120. A first collar 134 and
the second collar 136 are created by the material of the tubular
120 that remains above the upper end 124 of the openings 122 and
below the lower end 126 of the openings 122 after the openings 122
are created in the tubular 120. The openings 122 may be formed
through the tubular 20, 70, and 90 in a similar manner.
[0033] FIG. 11 depicts the generally flat material 10 from FIG. 1
after the generally flat material 10 has been rolled into the
tubular 20 so that the first side 18 and the second side 16 are in
contact with one another along their length. With the first side 18
and the second side 16 in contact with one another a portion of the
two sides 16 and 18 may be linked. For instance the two sides may
be linked along the contact portion of the two sides 18 and 16 from
the upper end 12 to any desired point such as point 19 and from the
lower end 14 to any desired point such as point 17 leaving the
contact portion of the two sides between point 19 and point 17
unlinked.
[0034] FIG. 12 depicts the tubular 20 from FIG. 11 having the upper
end 12, the lower end 14, and at least one opening 150 created
through the tubular 20.
[0035] When creating the opening 150 the material between the upper
end 152 and the lower end 154 of the tubular where the first side
18 and second side 16 are adjacent, whether linked or not, is
removed. The upper end 152 of the opening 150 may be located at
point 19, between point 19 and the upper end 12 of the tubular 20,
or between points 19 and 17. The lower end 154 of the opening 150
may be located at point 17, between point 17 and the lower end 14
of the tubular 20, or between points 17 and 19. Ribs 160 are
created by the material of the tubular 20 that remains between the
openings 150 after the openings 150 are created in the tubular 20.
A first collar 162 and the second collar 164 are created by the
material of the tubular 20 that remains above the upper end 152 of
the openings 150 and below the lower end 154 of the openings 150
after the openings 150 are created in the tubular 20. While only
the tubular with linear sides is depicted any created tubular may
be used. The opening 150 may be formed through tubular 50 in a
similar manner.
[0036] FIG. 13 depicts a tubular 140 having an upper end 142, a
lower end 144, openings 146, ribs 148, opening upper end 152,
opening lower end 154, and upper collar 156, and a lower collar
158. The ribs 148 have been expanded radially outward so that each
of the ribs 148 will have at least one portion, an apex 161 of each
of the ribs 148 that extends further radially outward than other
portions of each the ribs 148 or of the tubular 140. So that a
portion of each of the ribs 148, typically the apex 161 of each rib
148, will contact the wellbore or other tubular wall (not shown).
In many instances at least a portion of each of the ribs 148 will
be treated to enhance the ability of each of the ribs 148 to
elastically deform. Any treatment process such as heat treating,
cold treating, curing, or any other process known in the industry
may be used to enhance the ability each of the ribs 148 to
elastically deform.
[0037] In practice it is generally understood that the tubular 140
(i.e. a centralizer) as depicted in FIG. 13 is placed on a separate
tubular so that the collar 158, collar 156, and ribs 148 are
generally coaxial with the separate tubular and that each collar
158 and 156 has a reasonably tight fit on the separate tubular. The
centralizer may be allowed to slide up or down the separate tubular
within the limits of couplings that are typically attached at
either end of the separate tubular although more preferably at
least one of the collars 158 or 156 are attached to the separate
tubular. Collars 158 or 156 may be attached to the separate tubular
by any attachment system known in the industry. For instance the
collars 158 or 156 may be attached to the separate tubular as
disclosed by U.S. patent application Ser. Nos. 11/749,544,
12/042,989, 12/756,173, 13/019,084, 13/476,807, and 12/913,495
which are each incorporated by reference herein. The tubular 20,
50, 70, 80, or 90 placed on a separate tubular so that the collars
and the ribs may be generally coaxial with the separate tubular.
The tubular 20, 50, 70, 80, or 90 may be a centralizer in a similar
manner as described in relation to FIG. 13.
[0038] Bottom, lower, or downward denotes the end of the well or
device away from the surface, including movement away from the
surface. Top, upwards, raised, or higher denotes the end of the
well or the device towards the surface, including movement towards
the surface. While the embodiments are described with reference to
various implementations and exploitations, it will be understood
that these embodiments are illustrative and that the scope of the
inventive subject matter is not limited to them. Many variations,
modifications, additions and improvements are possible.
[0039] Plural instances may be provided for components, operations
or structures described herein as a single instance. In general,
structures and functionality presented as separate components in
the exemplary configurations may be implemented as a combined
structure or component. Similarly, structures and functionality
presented as a single component may be implemented as separate
components. These and other variations, modifications, additions,
and improvements may fall within the scope of the inventive subject
matter.
[0040] While the foregoing is directed to embodiments of the
present invention, other and further embodiments of the invention
may be devised without departing from the basic scope thereof, and
the scope thereof is determined by the claims that follow.
* * * * *