U.S. patent application number 12/269141 was filed with the patent office on 2009-03-05 for downhole draw down pump and method.
Invention is credited to Danny T. Williams.
Application Number | 20090057028 12/269141 |
Document ID | / |
Family ID | 34226995 |
Filed Date | 2009-03-05 |
United States Patent
Application |
20090057028 |
Kind Code |
A1 |
Williams; Danny T. |
March 5, 2009 |
Downhole Draw Down Pump and Method
Abstract
An apparatus for drawing down a fluid level in a wellbore. The
apparatus comprises a first tubular disposed within the wellbore so
that a wellbore annulus is formed. The apparatus further includes
an annular nozzle operatively attached to the first tubular, and
wherein the annular nozzle comprises: an annular adapter; and, a
suction tube that extends from the annular member into an inner
portion of the first tubular. The apparatus further comprises a
second tubular concentrically disposed within the first tubular so
that a micro annulus is formed therein. The apparatus may further
contain a jetting device for delivering an injected medium injected
from the micro annulus into the wellbore annulus, and a stabilizer
that stabilizes the second tubular within the first tubular. A
method of drawing down a fluid level is also disclosed.
Inventors: |
Williams; Danny T.; (Katy,
TX) |
Correspondence
Address: |
LONGMAN RUSSO;A PROFESSIONAL LAW CORPORATION
P.O. DRAWER 3408
LAFAYETTE
LA
70502-3408
US
|
Family ID: |
34226995 |
Appl. No.: |
12/269141 |
Filed: |
November 12, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11801678 |
May 10, 2007 |
7451824 |
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12269141 |
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11447767 |
Jun 6, 2006 |
7222675 |
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11801678 |
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10659663 |
Sep 10, 2003 |
7073597 |
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11447767 |
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Current U.S.
Class: |
175/213 ;
166/372 |
Current CPC
Class: |
E21B 43/124 20130101;
E21B 43/006 20130101; E21B 17/18 20130101 |
Class at
Publication: |
175/213 ;
166/372 |
International
Class: |
E21B 17/00 20060101
E21B017/00; E21B 43/00 20060101 E21B043/00 |
Claims
1. An apparatus for use in a wellbore, the apparatus comprising: a
first tubing member disposed within the wellbore so that a wellbore
annulus is formed therein, the first tubing member having a suction
tube device at a first end, and wherein said suction tube device
extends into an inner portion of said first tubing member; a second
tubing member disposed within said first tubing member so that a
micro annulus is formed therein, wherein a first end of said second
tubing member is positioned about said suction tube device, and
wherein said suction tube is in communication with said wellbore
annulus.
2. The apparatus of claim 1 further comprising stabilizer means,
disposed about said second tubing member, for stabilizing said
second tubing member within said first tubing member.
3. The apparatus of claim 2 further comprising jet means, disposed
within said first tubing member, for delivering an injected medium
from said micro annulus into the wellbore annulus.
4. The apparatus of claim 3 further comprising: means, disposed at
the surface, for injecting the injection medium into said micro
annulus.
5. The apparatus of claim 4 further comprising an inner tubing
restriction sleeve disposed within said second tubing member and
wherein said suction tube device extends into said inner tubing
restriction sleeve.
6. The apparatus of claim 5 wherein said injection medium is
selected from the group consisting of gas, air, or fluid.
7. The apparatus of claim 5 wherein said wellbore intersects and
extends past a coal bed methane gas seam so that a sump portion of
the wellbore is formed.
8. The apparatus of claim 7 wherein the apparatus is placed at a
position below the coal bed methane gas seam.
9. (canceled)
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Description
BACKGROUND OF THE INVENTION
[0001] This invention relates to a downhole pump. More
particularly, but not by way of limitation, this invention relates
to a downhole draw down pump used to withdraw fluid from a wellbore
and method.
[0002] In the production of oil and gas, a well is drilled in order
to intersect a hydrocarbon bearing deposit, as is well understood
by those of ordinary skill in the art. The well may be of vertical,
directional, or horizontal contour. Also, in the production of
natural gas, including methane gas, from coal bed seams, a wellbore
is drilled through the coal bed seam, and methane is produced via
the wellbore.
[0003] Water encroachment with these natural gas deposits is a well
documented problem. Once water enters the wellbore, production of
the hydrocarbons can be severely hampered due to several reasons
including the water's hydrostatic pressure effect on the in-situ
reservoir pressure. Down hole pumps have been used in the past in
order to draw down the water level. However, prior art pumps suffer
from several problems that limit the prior art pump's usefulness.
This is also true of wellbores drilled through coal beds. For
instance, in the production of methane from coal bed seams, a sump
is often times drilled that extends past the natural gas deposit.
Hence, water can enter into this sump. Water encroachment can
continue into the wellbore, and again the water's hydrostatic
pressure effect on the in-situ coal seam pressure can cause
termination of gas production. As those of ordinary skill will
recognize, for efficient production, the water in the sump and
wellbore should be withdrawn. Also, rock, debris and formation
fines can accumulate within this sump area and operators find it
beneficial to withdraw the rock and debris.
[0004] Therefore, there is a need for a downhole draw down pump
that can be used to withdraw a fluid contained within a wellbore
that intersects a natural gas deposit. These, and many other needs,
will be met by the invention herein disclosed.
SUMMARY OF THE INVENTION
[0005] An apparatus for use in a wellbore is disclosed. The
apparatus comprises a first tubular disposed within the wellbore so
that a wellbore annulus is formed therein, and wherein the first
tubular has a distal end and a proximal end. The apparatus further
includes an annular nozzle operatively attached to the distal end
of the first tubular, and wherein the annular nozzle comprises: an
annular adapter; and, a suction tube that extends from the annular
adapater into an inner portion of the first tubular. In one
embodiment, the suction tube may be threadedly attached to the
annular adapter.
[0006] The apparatus further comprises a second tubular
concentrically disposed within the first tubular so that a micro
annulus is formed therein, and wherein a first end of the second
tubular is positioned adjacent the suction tube so that a
restricted area is formed within an inner portion of the second
tubular.
[0007] The apparatus may further contain jet means, disposed within
the first tubular, for delivering an injected medium from the micro
annulus into the wellbore annulus. Also, the apparatus may include
stabilizer means, disposed about the second tubular, for
stabilizing the second tubular within the first tubular. The
apparatus may further contain an inner tubing restriction sleeve
disposed within the inner portion of the second tubular, and
wherein the inner tubing restriction sleeve receives the suction
tube.
[0008] Additionally, the apparatus may include means, located at
the surface, for injecting the injection medium into the micro
annulus. The injection medium may be selected from the group
consisting of gas, air, or fluid.
[0009] In one of the preferred embodiments, the wellbore intersects
and extends past a coal bed methane gas seam so that a sump portion
of the wellbore is formed. Also, in one of the preferred
embodiments, the apparatus is placed below the coal bed methane gas
seam in the sump portion. In another embodiment, the apparatus may
be placed within a wellbore that intersects subterranean
hydrocarbon reservoirs.
[0010] The invention also discloses a method of drawing down a
fluid column from a wellbore, and wherein the wellbore intersects a
natural gas deposit. The method comprises providing a first tubular
within the wellbore so that a wellbore annulus is formed therein,
the first tubing member having an annular nozzle at a first end.
The annular nozzle contains an annular adapter that is connected to
a suction tube, and wherein the suction tube extends into an inner
portion of the first tubular.
[0011] The method includes disposing a second tubular
concentrically within the first tubular so that a micro annulus is
formed, and wherein a first end of the second tubular is positioned
about the suction tube. A medium is injected into the micro annulus
which in turn causes a zone of low pressure within the suction
tube. Next, the fluid contained within the wellbore annulus are
suctioned into the suction tube. The fluid is exited from the
suction tube into an inner portion of the second tubular, and
wherein the fluid is mixed with the medium in the inner portion of
the second tubular. The fluids, solids and medium are then
discharged at the surface.
[0012] In one embodiment, the method may farther comprise injecting
the medium into the wellbore annulus and mixing the medium with the
fluid within the wellbore annulus. Then the medium and fluid is
forced into the suction tube.
[0013] The method may also include lowering the level of the fluid
within the wellbore annulus, and flowing the natural gas into the
wellbore annulus once the fluid level reaches a predetermined
level. The natural gas in the wellbore annulus can then be produced
to a surface collection facility.
[0014] In another preferred embodiment, a portion of the medium is
jetted from the micro annulus into the wellbore annulus, and the
medium portion is mixed with the fluid within the wellbore annulus.
The medium and fluid is forced into the suction tube. The level of
the fluid within the wellbore annulus is lowered. The injection of
the medium into the micro annulus is terminated once the fluid
level reaches a predetermined level. The natural gas can then be
produced into the wellbore annulus which in turn will be produced
to a surface collection facility.
[0015] In one of the preferred embodiments, the wellbore contains a
sump area below the level of the natural gas deposit and wherein
the suction member is positioned within the sump area.
Additionally, the natural gas deposit may be a coal bed methane
seam, or alternately a subterranean hydrocarbon reservoir
[0016] An advantage of the present invention is the novel annular
nozzle. Another advantage of the present invention includes the
apparatus herein disclosed has no moving parts. Another advantage
is that the apparatus and method will draw down fluid levels within
a wellbore. Another advantage is that the apparatus and method will
allow depletion of low pressure wells, or wells that have ceased
production due to insufficient in-situ pressure, and/or pressure
depletion.
[0017] Yet another advantage is that the apparatus and method
provides for the suctioning of fluids and solids. Another advantage
is it can be run in vertical, directional, or horizontal wellbores.
Another advantage is a wide range of suction discharge can be
implemented by varying medium injection rates. Another advantage is
that the device can suction from the wellbore both fluids as well
as solids.
[0018] A feature of the present invention is that the annular
nozzle provides for an annular flow area for the power fluid.
Another feature of the invention is that the annular nozzle
includes an annular adapter and suction tube and wherein the
annular adapter is attached to a tubular member, with the annular
adapter extending to the suction tube. Another feature is use of a
restriction adapter sleeve disposed on an inner portion of a second
tubular member. Yet another feature is that the restriction sleeve
may be retrievable.
[0019] Another feature includes use of jets that are placed within
the outer tubular member to deliver an injection medium to the
wellbore annulus. Yet another feature is that the jets can be
placed in various positions and directed to aid in evacuating the
wellbore annulus. Still yet another feature is that the suction
tube may contain a check valve to prevent a back flow of fluid
and/or solids.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] FIG. 1 depicts a first tubular member with suction member
disposed within a wellbore
[0021] FIG. 2 depicts a second tubular member having been
concentrically disposed within the first tubular member of FIG.
1.
[0022] FIG. 3 depicts a second embodiment of the apparatus
illustrated in FIG. 2.
[0023] FIG. 4 depicts the embodiment illustrated in FIG. 3 with
flow lines to depict the flow pattern within the wellbore.
[0024] FIG. 5 is a schematic illustration of the apparatus of the
present invention in use in a wellbore.
[0025] FIG. 6 is a cross sectional view of the apparatus taken from
line 6-6 of FIG. 4.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0026] Referring now to FIG. 1, a first tubular member 2 is shown
concentrically disposed into a wellbore 4. As used herein, a
wellbore can be a bore hole, casing string, or other tubular. In
the most preferred embodiment, the wellbore 4 is a casing string
The first tubular member 2 has been lowered into the wellbore 4
using conventional means such as by coiled tubing, work string,
drill string, etc. In one of the preferred embodiments, the
wellbore extends below the surface and will intersect various types
of subterranean reservoirs and/or mineral deposits. The wellbore is
generally drilled using various types of drilling and/or boring
devices, as readily understood by those of ordinary skill in the
art.
[0027] The first tubular member 2 disposed within the wellbore 4
creates a wellbore annulus 5. The wellbore 4 may be a casing string
cemented into place or may simply be a drilled bore hole. It should
be noted that while a vertical well is shown in the figures, the
wellbore 4 may also be of deviated, directional or horizontal
contour.
[0028] The first tubular member 2 will have an annular nozzle that
comprises an annular adapter and a suction tube. More specifically,
the annular adapter 6 is attached to the second end 8 of the first
tubular member 2. In the preferred embodiment, the annular adapter
6 contains thread means 10 that make-up with the thread means 12 of
the first tubular member 2. The annular adapter 6 has a generally
cylindrical outer surface 14 that has a generally reducing outer
surface portion which in turn extends radially inward to inner
portion 16 The inner portion 16 has thread means 18. The suction
tube 20 will extend from the annular adapter 6. More specifically,
the suction tube 20 will have thread means 22 that will cooperate
with the thread means 18 in one preferred embodiment and as shown
in FIG. 1. The suction tube 20 has a generally cylindrical surface
24 that then extends to a conical surface 26, which in turn
terminates at the orifice 28. The orifice 28 can be sized for the
pressure draw down desired by the operator at that point The
suction tube has an inner portion 29. Note that FIG. 1 shows the
opening 72 of the annular adapter 6.
[0029] FIG. 1 further depicts a plurality of jets. More
specifically, the jet 30 and jet 32 are diposed through the first
tubular member 2. The jets 30, 32 are positioned so to direct a
stream into the wellbore annulus 5. The jets are of nozzle like
construction and are positioned in opposite flow directions, at
different angles, and it is also possible to place the jets in
different areas on member 2 in order to aid in stirring the fluid
and solids within the wellbore annulus. Jets are usually sized
small in order to take minimal flow from the micro annulus (as
described below).
[0030] Referring now to FIG. 2, a second tubular member 34 is shown
having been concentrically disposed within the first tubular member
2 of FIG. 1. It should be noted that like numbers appearing in the
various figures refer to like components. Thus, the second tubular
member 34 has been concentrically lowered into the inner portion of
the first tubular member 2 via conventional means, such as by
coiled tubing, work string, drill string, etc. The second tubular
member 34 will have stabilizer means 36 and 38. The stabilizer
means 36, 38 may be attached to the outer portion of the second
tubular member 34 by conventional means such as by welding,
threads, etc. The stabilizer means may be a separate module within
the second tubular member 34. In one embodiment, three stabilizer
means are disposed about the outer portion of the second tubular
member 34. As shown in FIG. 2, the stabilizer means are attached to
the second tubular member 34. Additionally, the stabilizer means
36, 38 can be placed on the second tubular member 34 at any
position, direction and/or angle needed to stabilize second tubular
member 34 over suction tube 20.
[0031] Once the second tubular member 34 is concentrically
positioned within the first tubular member 2, a micro annulus 40 is
formed. The second tubular member 34 is placed so that the suction
tube 20 extends past an end 42 of the second tubular member 34. As
will be discussed in further detail later in the application, a
medium is injected into the micro annulus 40, and wherein the
medium will be directed about the end 42 into the passage 44 and up
into the inner diameter portion 46 of the second tubular member 34.
Note that the passage 44 is formed from the suction tube being
disposed within the second tubular member 34. The passage 44
represents an annular flow area of the annular nozzle that the
medium traverses through.
[0032] Referring now to FIG. 3, a second embodiment of the
apparatus illustrated in FIG. 2 will now be described. More
specifically, an inner tubing restriction sleeve 48 has been added
to the inner portion 46 of the second tubular member 34. FIG. 3
also shows two additional jets, namely jet 50 and jet 52. The jets
are of nozzle like construction. The jets may be placed in varying
positions and/or angle orientation in order to lift the wellbore
fluids and solids to the surface. The position and/or angle
orientation of the jets is dependent on specific wellbore
configurations, flow characteristics, and other design
characteristics. The jets 50, 52 are positioned to direct a portion
of the micro annulus injection medium exiting the jets 50, 52 into
the bottom of the suction tube 20.
[0033] The inner tubing restriction sleeve 48 has an outer diameter
portion 54 that will cooperate with the inner diameter portion 46
of the second tubular member 34. Extending radially inward, the
sleeve 48 has a first chamfered surface 56 that extends to an inner
surface 58 which in turn extends to conical surface 60. The conical
surface 60 then stretches to radial surface 62 which in turn
extends to the conical surface 64 which then stretches to the
radial surface 66. FIG. 3 further depicts thread means 68 on the
restriction sleeve 48 that will cooperate with thread means 70 on
the second tubular member 34 for connection of the restriction
sleeve 48 to the second tubular member 34. Other means for
connecting are possible, such as by welding, or simply by making 21
the restriction sleeve integral with the second tubular member 34.
It should be noted that the 22 inner diameter portion of the
restriction sleeve 48 can vary in size according to the various
needs of a specific application. In other words, the inner diameter
of the restriction sleeve 48 can be sized based on the individual
well needs such as downhole pressure, fluid density, solids
content, etc. In FIG. 3, the passage 44 is formed between the
restriction sleeve 48 and the suction tube 20.
[0034] Reference is now made to FIG. 4, and wherein FIG. 4 depicts
the embodiment illustrated in FIG. 3 with flow lines to depict the
flow pattern within the wellbore 4. The operator would inject a
medium, such as gas, air, or fluid, into the micro annulus 40. The
medium will generally be injected from the surface. The medium,
sometimes referred to as a power fluid, proceeds down the micro
annulus 40 (as seen by the arrow labeled "AA") and into the annular
nozzle. More specifically, the medium will flow around the end 42
and in turn into the passage 44 (see arrow "B"). Due to the suction
tube 20 as well as the restriction sleeve 48, the flow area for the
injected medium has been decreased. This restriction in flow area
will in turn cause an increase in the velocity of the medium within
the passage 44. As the medium continues, a further restriction is
experienced once the medium flows past the conical surface 64 (see
arrow "C"), and accordingly, the velocity again increases. The
velocities within the passage 44 and immediately above the orifice
28 would have also increased. The pressure within the suction tube
20, however, will be experiencing a suction due to the venturi
effect. The pressure P1 is greater than the pressure at P2 which
causes flow into, and out of, the suction tube 20. As noted
earlier, the orifice 28 and/or restriction sleeve 48 can be sized
to create the desired pressure draw down. Hence, the fluid and
solids contained within the wellbore annulus 5 will be suctioned
into the suction tube 20 via opening 72. The suction thus created
will be strong enough to suction fluids and solids contained within
the well bore annulus 5 (see arrow "D"). Once the fluid and solids
exit the orifice 28, the fluid and solids will mix and become
entrained with the medium within the throat area denoted by the
letter "T" and will be carried to the surface.
[0035] The jets 30, 32 will also take a portion of the medium
injected into the micro annulus 40 and direct the medium into the
wellbore annulus 5. This will aid in mixing and moving the fluid
and solids within the wellbore annulus 5 into the suction tube 20.
FIG. 4 also depicts the jets 50, 52 that will direct the medium
that has been injected into the micro annulus into the suction tube
20. Again, this will aid in stirring the annular fluid and solids)
and causing a suction at the opening 72 and aid in directing the
fluid and/or solids into the suction tube 20.
[0036] According to the teachings of this invention it is also
possible to place a check valve (not shown) within the suction tube
20. The check valve would prevent the fluid and solids from falling
back down. Also, it is possible to make the restriction sleeve 48
retrievable so that the restriction sleeve 48 could be replaced due
to the need for a more appropriate size, wear, and/or general
maintenance. Moreover, the invention may include placement of an
auger type of device (not shown) which would be operatively
associated with the annular adapter 6. The auger means would
revolve in response to the circulation of the medium which in turn
would mix and crush the solids.
[0037] Referring now to FIG. 5, a schematic illustration of one of
the preferred embodiments of the apparatus of the present invention
in use in a wellbore will now be described. More specifically, the
wellbore 4 intersects a natural gas deposit. In FIG. 5, the natural
gas deposit is a coal bed methane seam. In the case of a coal bed
methane seam, and as those of ordinary skill will recognize, a bore
hole 74 is drilled extending from the wellbore 4. As shown in FIG.
5, the bore hole 74 is essentially horizontal, and the bore hole 74
may be referred to as a drainage bore hole 74. The methane gas
embedded within the coal bed methane seam will migrate, first, to
the drilled bore hole 74 and then, secondly, into the wellbore 4.
It should be noted that the invention is applicable to other
embodiments. For instance, the natural gas deposit may be a
subterranean hydrocarbon reservoir. In the case where the natural
gas deposit is a subterranean hydrocarbon reservoir, there is no
requirement to drill a drainage bore hole. The in-situ hydrocarbons
will flow into the wellbore annulus 5 due to the permeability of
the reservoir. Hence, the invention herein described can be used in
coal bed methane seams as well as traditional oil and gas
subterranean reservoirs.
[0038] The annular adapter 6 is shown attached to the first tubular
member 2. The suction tube 20 extends into the second tubular
member 34 and inner tubing restriction sleeve 48 as previously
noted. The medium is injected from the surface from a generator
means 76. The medium is forced (directed) down the wellbore 4. As
noted earlier, the medium flowing through the annular nozzle will
in turn cause a suction within the opening 72 so that the fluid and
solids that have entered into the wellbore 4 can be withdrawn.
[0039] The fluid and solids that enter into the inner portion 46 of
the second tubular member 34 will be delivered to separator means
78 on the surface for separation and retention. As the fluid is
drawn down to a sufficient level within the wellbore 4, gas can
migrate from the natural gas deposit into the wellbore 4. The gas
can then be produced to the surface to production facility means 79
for storage, transportation, sale, etc.
[0040] As seen in FIG. 5, the wellbore 4 contains a sump area 80.
Thus, in one embodiment, the sump area 80 can collect the fluid and
solids which in turn will be suctioned from the wellbore 4 with the
novel apparatus herein disclosed. The fluid level is drawn down
thereby allowing the gas from the deposit to enter into the
wellbore 4 for production to the surface. If the subterranean
mineral deposit is pressure deficient or is subject to water
encroachment, then water may migrate back into the wellbore, and
into the sump. The water level can rise within the wellbore 4,
thereby reducing or shutting-off gas production. Once the water
rises to a sufficient level so that gas production is interrupted,
then, and according to the teachings of the present invention, the
fluid level can be drawn down using the suction method and
apparatus herein disclosed, and production can be restored. This
can be repeated indefinitely or until the subterranean mineral
deposit is depleted.
[0041] It should also be noted that it is possible to also inject
the injection medium down the wellbore annulus 5. Hence, the
operator could inject into both the micro annulus 40 and wellbore
annulus 5, or either, depending on conditions and desired down hole
effects.
[0042] FIG. 6 is a cross sectional view of the apparatus taken from
line 6-6 of FIG. 4. In the view of FIG. 6, the wellbore annulus 5
is shown. The micro annulus 40 is shown, and as previously
described, the medium (power fluid) is injected down the micro
annulus. The FIG. 6 also shows the passage 44, which is formed due
to the configuration of the annular nozzle, and wherein the passage
44 represents an annular flow area for passage of the power fluid.
The suction tube's inner portion is seen at 29 and wherein the
fluid and solids being suctioned into the suction tube's inner
portion 29 is being drawn from the wellbore annulus 5.
[0043] As understood by those of ordinary skill in the art, a
stream that exits a restriction will have considerable kinetic
energy associated therewith, and wherein the kinetic energy results
from a pressure drop generated by the restriction. Generally, the
sizing of the restriction determines the pressure drop, and a
desired pressure drop can be caused by varying the size of passage
44. This can be accomplished by varying the diameter of the
restriction sleeve which reduces flow area, increase velocity and
in turn effects a pressure drop. As noted earlier, a portion of
FIG. 6 depicts the flow area created due to placement of the
restriction sleeve 48. Hence, if the restriction sleeve's 48 inner
diameter portion is enlarged, then the effective area of the
passage 44 would be reduced thereby increasing the pressure drop.
By the same token, the size of the suction tube 20 walls could be
enlarged, thereby reducing the effective flow area which in turn
would cause an increase pressure drop.
[0044] While preferred embodiments of the present invention have
been described, it is to be understood that the embodiments
described are illustrative only and that the scope of the invention
is to be defined solely by the appended claims when accorded a fill
range of equivalence, many variations and modifications naturally
occurring to those skilled in the art from a review thereof
* * * * *