U.S. patent application number 17/524837 was filed with the patent office on 2022-03-10 for reverse burn power charge for a wellbore tool.
This patent application is currently assigned to DynaEnergetics Europe GmbH. The applicant listed for this patent is DynaEnergetics Europe GmbH. Invention is credited to Liam McNelis.
Application Number | 20220074718 17/524837 |
Document ID | / |
Family ID | |
Filed Date | 2022-03-10 |
United States Patent
Application |
20220074718 |
Kind Code |
A1 |
McNelis; Liam |
March 10, 2022 |
REVERSE BURN POWER CHARGE FOR A WELLBORE TOOL
Abstract
A power charge and method for actuating a wellbore tool with a
power charge. The power charge may include a groove formed in the
outer surface of the power charge. The power charge may include a
first volume containing a first energetic material and a second
volume containing a second energetic material that is a faster
burning material compared to the first energetic material. The
wellbore tool may include a tool body wall defining a power charge
cavity. The groove formed in the outer surface of the power charge
may define a gas pressure path between the tool body wall and the
power charge, within the power charge cavity, when the power charge
is inserted into the power charge cavity. The method may include
coupling an initiator to the wellbore tool and initiating
combustion of the first energetic material and the second energetic
material to actuate the wellbore tool.
Inventors: |
McNelis; Liam; (Bonn,
DE) |
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Applicant: |
Name |
City |
State |
Country |
Type |
DynaEnergetics Europe GmbH |
Troisdorf |
|
DE |
|
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Assignee: |
DynaEnergetics Europe GmbH
Troisdorf
DE
|
Appl. No.: |
17/524837 |
Filed: |
November 12, 2021 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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16886257 |
May 28, 2020 |
11204224 |
|
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17524837 |
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62853824 |
May 29, 2019 |
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International
Class: |
F42B 3/10 20060101
F42B003/10; E21B 23/04 20060101 E21B023/04; E21B 33/10 20060101
E21B033/10; F42B 3/26 20060101 F42B003/26; F42D 1/04 20060101
F42D001/04; F42B 3/04 20060101 F42B003/04; E21B 41/00 20060101
E21B041/00 |
Claims
1. A power charge for actuating a wellbore tool, the power charge
comprising: a first end and a second end opposite the first end; an
outer surface extending from the first end to the second end; a
groove formed in the outer surface; a first volume comprising a
first energetic material; and a second volume comprising a second
energetic material, wherein the second energetic material is a
faster burning material compared to the first energetic
material.
2. The power charge of claim 1, wherein the second volume extends
from a position adjacent the first end towards the second end.
3. The power charge of claim 1, wherein the second volume extends
from a position adjacent the first end to a position adjacent the
second end.
4. The power charge of claim 3, wherein the second volume extends
all the way through the power charge from the first end to the
second end.
5. The power charge of claim 1, wherein the second volume is
coaxial with the first volume.
6. The power charge of claim 1, further comprising an indentation
in the power charge adjacent the first end.
7. The power charge of claim 6, further comprising a booster
positioned within the indentation.
8. The power charge of claim 6, wherein the second volume extends
from a position adjacent the indentation, in a direction away from
the indentation.
9. The power charge of claim 1, further comprising a path formed
within the first energetic material for directing pressurized gas
out of the power charge, wherein the second energetic material
fills at least a portion of the path.
10. A wellbore tool including a power charge for actuating the
wellbore tool, comprising: a tool body wall defining a power charge
cavity, wherein the power charge is positioned within the power
charge cavity and the power charge includes: a first end and a
second end opposite the first end, an outer surface extending from
the first end to the second end, a groove formed in the outer
surface, a first volume comprising a first energetic material, and
a second volume comprising a second energetic material that is a
faster burning material compared to the first energetic
material.
11. The wellbore tool of claim 10, further comprising an initiator
holder positioned within the power charge cavity and configured for
receiving and positioning an initiator adjacent to the power charge
within the power charge cavity, wherein the initiator holder is
configured for positioning an initiating output portion of the
initiator adjacent to an ignition portion of the power charge.
12. The wellbore tool of claim 11, wherein the ignition portion of
the power charge includes the first energetic material or the
second energetic material.
13. The wellbore tool of claim 12, wherein the ignition portion of
the power charge includes the second energetic material and the
initiator holder is configured for positioning the initiating
output portion of the initiator adjacent to the second volume.
14. The wellbore tool of claim 11, wherein the power charge further
includes an indentation in the power charge and a booster
positioned within the indentation, wherein the initiator holder is
configured for positioning the initiating output portion of the
initiator adjacent to the booster.
15. The wellbore tool of claim 10, further comprising a channel
open to and extending, through the tool body wall, from the power
charge cavity to an outside of the tool body wall.
16. The wellbore tool of claim 15, wherein the groove defines a gas
pressure path between the tool body wall and the power charge,
within the power charge cavity, and the gas pressure path is open
to the channel.
17. The wellbore tool of claim 10, further comprising a path formed
within the first energetic material for directing pressurized gas
out of the power charge, wherein the second energetic material
fills at least a portion of the path.
18. A method for actuating a wellbore tool with a power charge,
comprising: providing the wellbore tool including a power charge
cavity defined by a tool body wall of the wellbore tool; inserting
the power charge into the power charge cavity, wherein the power
charge includes a first end and a second end opposite the first
end, an outer surface extending from the first end to the second
end, a groove formed in the outer surface, wherein the groove is
configured for defining a gas pressure path between the tool body
wall and the power charge, within the power charge cavity, when the
power charge is inserted into the power charge cavity, a first
volume comprising a first energetic material, and a second volume
comprising a second energetic material that is a faster burning
material compared to the first energetic material; and coupling an
initiator to the wellbore tool, wherein the initiator is configured
for initiating an ignition portion of the power charge and thereby
causing combustion of the first energetic material and the second
energetic material and generation of gas pressure from combustion
of the first energetic material and the second energetic material,
wherein the gas pressure travels along the gas pressure path and
actuates the wellbore tool.
19. The method of claim 18, wherein the tool body wall includes a
channel open to and extending through the tool body wall, from the
power charge cavity to an actuation chamber of the wellbore tool,
and the gas pressure builds up in the actuation chamber to actuate
the wellbore tool.
20. The method of claim 19, wherein the gas pressure path is open
to the channel.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. application Ser.
No. 16/886,257 filed May 28, 2020, which claims the benefit of U.S.
Provisional Patent Application No. 62/853,824 filed May 29, 2019,
the entire contents of which are incorporated herein by
reference.
BACKGROUND OF THE DISCLOSURE
[0002] Oil and gas are extracted by subterranean drilling and
introduction of tools into the resultant wellbore for performing
various functions. The work performed by tools introduced in a
wellbore may be achieved by a force exerted by expanding gases; the
expanding gases may be the result of combustion of an energetic
material.
[0003] One example of a wellbore tool is a setting tool. Among
other functions, a setting tool is utilized to place plugs at
locations inside the wellbore to seal portions of the wellbore from
other portions. The force exerted to set a plug is typically
exerted on a piston in the setting tool, with the piston acting to
deform or displace portions of the plug which then engage the walls
of the wellbore. The engagement of the wellbore wall by the
deformed portions of the plug hold the plug, as well as any
elements attached to the plug, stationary in the wellbore. The plug
and any associated elements may completely or partially seal the
wellbore, and the associated elements may function to vary this
complete/partial blockage depending upon circumstances.
[0004] Primarily used during completion or well intervention, a
plug may pressure isolate a part of the wellbore from another part.
For example, when work is carried out on an upper section of the
well, the lower part of the wellbore must be isolated and plugged;
this is referred to as zonal isolation. Plugs can be temporary or
permanent. Temporary plugs can be retrieved whereas permanent plugs
can only be removed by destroying them with a drill. There are
number of types of plugs, e.g., bridge plugs, cement plugs, frac
plugs and disappearing plugs. Plugs may be set using a wire-line,
coiled tubing, drill pipe or untethered drones. In a typical
operation, a plug can be disposed into a well and positioned at a
desired location in the wellbore. A setting tool may be attached to
and lowered along with the plug or it may be lowered after the
plug, into an operative association therewith.
[0005] The expanding gases in a tool typically result from a
chemical reaction involving a power charge. In the example of a
setting tool, activation of the chemical reaction in the power
charge results in a substantial force being exerted on the setting
tool piston. When it is desired to set the plug, the
self-sustaining chemical reaction in the power charge is initiated,
resulting in expanding gas exerting a substantial force on the
piston. The piston being constrained to movement in a single
direction, the substantial force causes the piston to move axially
and actuate the plug to seal a desired area of the well. The
substantial force exerted by the power charge on the piston can
also shear one or more shear pins or similar frangible members that
serve certain functions, e.g., holding the piston in place prior to
activation and separating the setting tool from the plug.
[0006] The force applied to a tool by the power charge must be
controlled; it must be sufficient to actuate the tool reliably but
not so excessive as to damage the downhole tools or the wellbore
itself. Also, even a very strong force can fail to properly actuate
a tool if delivered too abruptly or over too short a time duration.
Even if a strong force over a short time duration will actuate a
tool, such a set-up is not ideal. That is, a power charge
configured to provide force over a period of a few seconds or tens
of seconds instead of a few milliseconds is sometimes required and
the desired option. In the context of a setting tool, such an
actuation is referred to as a "slow set". Depending on the
particular function of a given tool and other parameters, favorable
force characteristics may be provided by a force achieving work
over a period of milliseconds, several seconds or even longer.
[0007] FIG. 1 shows a power charge 116 contained in a prior art
generic wellbore tool 60. A chemical reaction in power charge 116
results in expanding gas exerting a force 86 on a piston 80 or
other force transferring element. The piston 80, in turn, exerts an
actuation force 84 to accomplish a function of the generic tool 60.
Initiation of the chemical reaction, e.g., combustion, begins at a
section of power charge 116 remote from piston 80 and the chemical
reaction proceeds in a direction 88 toward piston 80. A problem in
the prior art is that the portion of the power charge 116 that has
not undergone the chemical reaction may block the expanding gas
from exerting the force 86 on piston 80. Thus, expanding gas
pressure will increase until it is able to exert a force on the
piston 80 and begin moving the piston 80 to exert the actuation
force 84 to achieve the function of the generic tool 60.
[0008] In view of the disadvantages associated with currently
available power charges, there is a need for a safe, predictable
and economical power charge for use in wellbore tools. The improved
power charge will reduce extraneous forces developed during the
chemical reaction, i.e., a much-improved force/time profile will be
achieved. Such improvements may result in smaller power charges
being required and reduced maximum forces within the tool; both of
these results will reduce the likelihood of inadvertent damage to
the tool.
BRIEF DESCRIPTION OF THE EXEMPLARY EMBODIMENTS
[0009] In an aspect, the disclosure is directed to a power charge
for actuating a wellbore tool. An exemplary power charge has a
first end and a second end opposite the first end, and an outer
surface extending from the first end to the second end. A groove is
formed in the outer surface of the power charge. The power charge
includes a first volume containing a first energetic material and a
second volume containing a second energetic material. The second
energetic material is a faster burning material compared to the
first energetic material.
[0010] In another aspect, the disclosure is directed to a wellbore
tool including a power charge for actuating the wellbore tool. An
exemplary wellbore tool includes a tool body wall that defines a
power charge cavity. The power charge is positioned within the
power charge cavity and includes a first end and a second end
opposite the first end, and an outer surface extending from the
first end to the second end. A groove is formed in the outer
surface of the power charge. The power charge includes a first
volume containing a first energetic material and a second volume
containing a second energetic material that is a faster burning
material compared to the first energetic material.
[0011] In another aspect, the disclosure is directed to a method
for actuating a wellbore tool with a power charge. An exemplary
method includes providing the wellbore tool including a power
charge cavity defined by a tool body wall of the wellbore tool, and
inserting the power charge into the power charge cavity. The
exemplary power charge includes a first end and a second end
opposite the first end, and an outer surface extending from the
first end to the second end. A groove is formed in the outer
surface of the power charge and defines a gas pressure path between
the tool body wall and the power charge, within the power charge
cavity, when the power charge is inserted into the power charge
cavity. The power charge includes a first volume containing a first
energetic material and a second volume containing a second
energetic material that is a faster burning material compared to
the first energetic material. The method further includes coupling
an initiator to the wellbore tool. Initiating the initiator
initiates an ignition portion of the power charge causing
combustion of the first energetic material and the second energetic
material and generation of gas pressure from combustion of the
first energetic material and the second energetic material. The gas
pressure travels along the gas pressure path and is used to actuate
the wellbore tool.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] A more particular description will be rendered by reference
to specific exemplary embodiments thereof that are illustrated in
the appended drawings. Understanding that these drawings depict
only exemplary embodiments thereof and are not therefore to be
considered to be limiting of its scope, the exemplary embodiments
will be described and explained with additional specificity and
detail through the use of the accompanying drawings in which:
[0013] FIG. 1 is a cross-sectional, side, plan view of a generic
prior art wellbore tool that utilizes a power charge to perform
work;
[0014] FIG. 2 is a one-quarter-sectional, side, perspective view of
a setting tool in accordance with an exemplary embodiment;
[0015] FIG. 3 is a cross-sectional, side, plan view of a setting
tool in accordance with an exemplary embodiment;
[0016] FIG. 4 is a cross-sectional, side, plan view of a power
charge in accordance with an exemplary embodiment;
[0017] FIG. 5A is an end, plan view of the power charge power
charge shown in FIG. 4 viewed from the perspective of line A-A;
[0018] FIG. 5B is a cross-sectional, plan view of the power charge
shown in FIG. 4 taken at line B-B;
[0019] FIG. 5C is a cross-sectional, plan view of the power charge
shown in FIG. 4 taken at line C-C;
[0020] FIG. 6 is a cross-sectional, side, plan view of a power
charge in accordance with an exemplary embodiment;
[0021] FIG. 7 is a cross-sectional, side, plan view of a portion of
a setting tool in accordance with an exemplary embodiment; and
[0022] FIG. 8 is a side, perspective view of a power charge in
accordance with an exemplary embodiment.
[0023] Various features, aspects, and advantages of the exemplary
embodiments will become more apparent from the following detailed
description, along with the accompanying figures in which like
numerals represent like components throughout the figures and text.
The various described features are not necessarily drawn to scale
but are drawn to emphasize features of the exemplary
embodiments.
[0024] The headings used herein are for organizational purposes
only and are not meant to limit the scope of the description or the
claims. To facilitate understanding, reference numerals have been
used, where possible, to designate like elements common to the
figures.
DETAILED DESCRIPTION
[0025] Reference will now be made in detail to various exemplary
embodiments. Each example is provided by way of explanation and is
not meant as a limitation and does not constitute a definition of
all possible embodiments.
[0026] In the description that follows, the terms "setting tool",
"mandrel", "initiator", "power charge", "piston", "bore",
"apertures" and/or "channels"; and other like terms are to be
interpreted and defined generically to mean any and all of such
elements without limitation of industry usage. Such terms used with
respect to exemplary embodiments in the drawings should not be
understood to necessarily connote a particular orientation of
components during use.
[0027] As used herein, the term "cylinder" includes cylinders and
prisms having a base of any shape. In addition, collections of
cylinders having different base shapes and sizes stacked together
are also encompassed by the term "cylinder".
[0028] For purposes of illustrating features of the exemplary
embodiments, examples will now be introduced and referenced
throughout the disclosure. Those skilled in the art will recognize
that these examples are illustrative and not limiting and are
provided purely for explanatory purposes. For example, the
exemplary embodiments presented in FIGS. 2 and 3 show the use of a
power charge 116 in exemplary setting tools. Although shown in the
context of a setting tool 100, the power charge 116 presented
herein may be utilized in any wellbore tool capable of being
actuated by expanding gas from a chemical reaction, e.g.,
combustion. U.S. patent application Ser. No. 16/858,041 filed Apr.
24, 2020, which is commonly owned by DynaEnergetics Europe GmbH and
incorporated herein by reference in its entirety, provides
additional details regarding setting tools.
[0029] FIG. 2 illustrates a perspective, partial quarter-sectional
view of an exemplary setting tool 100 for actuating a tool 102 in a
wellbore. The setting tool 100 includes an inner piston 104 having
a proximal end 106 and a distal end 108. An intermediate section of
the inner piston 104 has an annular wall 112 enclosing a cavity
114. The cavity 114 is configured to receive a power charge 116
therein. The power charge 116 is not shown in cross section. Thus,
only the external surface of power charge 116 is shown in FIG. 2.
An initiator 118 may be positioned proximate to the power charge
116. The initiator 118 is used to initiate combustion of the power
charge 116 to form a combustion gas pressure inside the cavity
114.
[0030] Another component of setting tool 100 is an outer sleeve 120
having a piston proximal end 122, a piston distal end 124, a body
110, and a central bore 126. The outer sleeve 120 is configured to
slideably receive the inner piston 104. A generally annular
expansion chamber 128 may be defined by a portion of the central
bore 126 of the outer sleeve 120 and a portion of the annular wall
112 of the inner piston 104. A gas diverter channel 134 extends
through the annular wall 112 of the inner piston 104. The gas
diverter channel 134 is configured to allow gas pressure
communication between the cavity 114 containing power charge 116
and the expansion chamber 128. Accordingly, in the circumstance
where the combusting portion of the power charge 116 has an
unimpeded gas pressure path to channel 134, the combustion gas will
pass through the gas diverter channel 134 and into the expansion
chamber 128. Increasing amounts of gaseous combustion products from
burning power charge 116 will increase the pressure in the cavity
114, the gas diverter channel 134 and the expansion chamber 128.
Expansion chamber 128 is so named because it is adapted to expand
in volume as a result of axial movement of the outer sleeve 120
relative to the inner piston 104. The increasing gas pressure in
the expansion chamber 128 will exert an axial force on outer sleeve
120 and inner piston 104, resulting in the outer sleeve 120 sliding
axially toward tool 102 and expansion chamber 128 increasing in
volume.
[0031] Referring again to FIG. 2, the initiator 118 is configured
for positioning in an initiator holder 138. Initiator 118 may be of
the type described in U.S. Pat. No. 9,605,937 issued Mar. 28, 2017,
which is commonly owned by DynaEnergetics Europe GmbH and
incorporated herein by reference in its entirety, and comprise an
initiator head 146 and an initiator shell 136. The initiator shell
136 may contain an electronic circuit board (not shown) and an
element, e.g., a fuse head (not shown), capable of converting an
electrical signal into an ignition, flame or pyrotechnical output.
Initiator head 146 includes an electrically contactable line-in
portion 148 through which electrical signals may be conveyed to the
electronic circuit board of initiator 118.
[0032] The initiator holder 138 may be configured for positioning
the initiator shell 136 adjacent the power charge 116 within the
inner piston 104. The initiator 118 is positioned sufficiently
close to power charge 116 such that ignition of the initiator 118
will initiate combustion of power charge 116.
[0033] In accordance with an embodiment, power charge 116 occupies
a volume of a cylinder, typically an elongated cylinder having an
initiation end 186 and a distal end 184 with the volume 178 of the
power charge 116 between the initiation end 186 and the distal end
184. The initiation end 186 includes an ignition portion 188 of the
power charge 116, i.e., the place where combustion of the power
charge 116 is initiated. Combustion of the power charge 116 will
proceed from the ignition portion 188 through the volume of the
power charge 178 in any direction where unreacted energetic
material is sufficiently close to reacting, i.e., burning,
energetic material. Therefore, combustion of the power charge 116
will generally proceed from the initiation end 186 to the distal
end 184 of the power charge. The rate at which combustion will
proceed in the power charge 116 is discussed hereinbelow. The
exothermic chemical reaction, e.g., combustion or burning, in the
power charge 116 results in replacement of the solid energetic
material of the power charge volume 178 with gas and a small amount
of particulate residual material. Since the cavity 114 is sealed by
sub 512 and bulkhead 514 (FIG. 3), it has a fixed volume. Thus, the
gas produced by the exothermic chemical reaction results in
increasing gas pressure within the cavity 114.
[0034] In current setting tool wellbore tools, a path does not
initially exist for gas pressure from the combustion gas produced
early in the combustion of power charge 116 to reach the gas
diverter channel 134. A time delay occurs before such a gas
pressure path is opened. The pressure built up in the cavity 114
prior to a path to the gas diverter channel 134 being opened is
delivered in a single pulse of a short burst of high force. Thus,
current setting tools often have problems delivering a "slow set",
i.e., a force over a period of seconds to minutes instead less than
a second or, perhaps, less than several seconds. Thus, the
favorable force characteristics achievable with a slow set may be
difficult or impossible to achieve with currently available
wellbore tools.
[0035] The most commonly used energetic material, i.e., chemical
reactant resulting in expanding gas, is black powder. Black powder,
also known as gunpowder, is the earliest known chemical explosive
and includes sulfur, charcoal and potassium nitrate (saltpeter,
KNO.sub.3). The sulfur and charcoal act as fuels while the
saltpeter is an oxidizer. Because of the amount of heat and gas
volume that it generates when burned, black powder has been used as
a propellant for about 1000 years in firearms, artillery, rockets,
and fireworks, and as a blasting powder in quarrying, mining, and
road building. Black powder is referred to as a low explosive
because of its slow reaction rate relative to high explosives and
consequently low brisance. Low explosives deflagrate, i.e., burn,
at subsonic speeds in contrast to a supersonic wave generated by
the detonation of high explosives. Ignition of black powder
generates gas. When generated in a closed and constant volume, the
increased amount of gas result in increased pressure in the closed
volume. The force of this increased pressure in a closed volume may
be utilized to perform work.
[0036] There exist a number of `substitutes` for black powder.
Various parameters may be reduced or enhanced in a black powder
substitutes ("BPS"). For example, the sensitivity as an explosive
may be reduced while the efficiency as a propellant may be
increased. The first widely used BPS was Pyrodex.RTM.. Pyrodex.RTM.
will produce a greater amount of gas per unit mass than black
powder but has a reduced sensitivity to ignition. Both of these
parameters may be considered improvements over black powder. Triple
Seven.RTM. and Black Mag3.RTM. are sulfurless BPS that burn more
quickly and develop greater pressure.
[0037] Rate of burn for black powder and BPS is a notoriously
difficult parameter to measure or on which to find accurate data.
This is possibly because of the number of variables that can have
an effect on the rate of burn, i.e., black powder and BPS will burn
at different rates depending upon a number of factors. Regardless,
pure black powder and BPS will usually have a burn rate on the
order of about 0.3 to about 0.7 feet per second ("ft/sec") which
may be converted to about 18 feet per minute to about 42 feet per
minute ("ft/min"). Mixing black powder or BPS with additives that
are not fuel or oxidizer components contributing to the chemical
reaction, i.e., "inert" ingredients, will typically slow the burn
rate. Further, the higher the proportion of inert ingredients to
black powder or BPS, the slower the burn rate will be.
[0038] The burn rate of a mixture containing black powder or BPS
may be adjusted from very near the burn rate of pure black powder
or BPS, i.e., by adding very little inert material, to very much
slower, i.e., by adding a large proportion of inert material.
Formulations for the power charge 116 for use in a wellbore tool
are known that have a burn rate on the order of about 12 ft/min
down to about 0.5 ft/min or even lower. Thus, a fast-burning
portion of the power charge may contain 50 to 100% black powder or
BPS and 0 to 50% potassium nitrate (KNO.sub.3).
[0039] In an embodiment, a formulation for a slow-burning power
charge may contain about 6% by weight of black powder or BPS,
sodium nitrate (NaNO.sub.3) as fuel, wheat flour
(C.sub.6H.sub.10O.sub.5) as oxidizer and an epoxy resin as a
binder. Varying the ratio of epoxy resin provides a means of
varying the burn rate for the power charge 116. In addition, the
selection of epoxy resin may have an impact on the burn rate. In an
embodiment, a power charge permitting a slow-set are formulated to
produce burn rates from about 3 ft/min to about 0.13 ft/min. The
slow-burning portion of the power charge may contain 40 to 75%
sodium nitrate (NaNO.sub.3), 0 to 10% black powder or BPS, 15 to
45% wheat flour, and 10 to 30% epoxy.
[0040] Utilizing the 18 ft/min to 42 ft/min values for pure black
powder or BPS and power charge formulations with values of 3 ft/min
to about 0.13 ft/min results in relative burn rates from about 6:1
to about 300:1. In an embodiment, relative burn rates between a
fast reacting energetic material and a slow reacting energetic
material between about 100:1 and 300:1 are contemplated.
[0041] As stated previously, a problem with current wellbore tools
is that a path does not initially exist for gas pressure from the
combustion gas produced early in the combustion of power charge 116
to reach the gas diverter channel 134. Thus, regardless of the
reaction rate of the energetic material, a time delay occurs before
the gas pressure is able to exert a force where it is needed. Also,
the pressure built up in the cavity 114 prior to a path to the gas
diverter channel 134 being opened is delivered as a short burst of
high force.
[0042] In an embodiment, a power charge 116 is presented that opens
the path from the combustion gas created by the burning power
charge 116 to the portions of the wellbore tool upon which a force
needs to be exerted far earlier in the combustion process than in
the prior art. For the wellbore tools presented in FIG. 2 and FIG.
3, this path includes the gas diverter channel 134 and the portions
of the wellbore tool where force is exerted are the portions of the
outer sleeve 120 and the inner piston 104 forming expansion chamber
128.
[0043] FIG. 4 illustrates a cross-section of the power charge in
accordance with an embodiment. The outer dimensions of the power
charge 116 may be identical to those found in the prior art, thus
permitting its use in existing generic wellbore tools 60. The
portion 180 that forms the majority of power charge 116 of FIG. 4
is a slow-burning formulation of energetic material, e.g., a power
charge formulation with a burn-rate on the order of about 1 ft/min
to about 0.13 ft/min. A portion 182 of power charge 116 is a
relatively fast-burning energetic material. For example, the
portion 182 may be pure black powder or BPS and have a burn rate on
the order of about 18 ft/min up to about 42 ft/min. Each of the
slow-burning portion 180 and the fast-burning portion 182 occupy a
separate volume of the power charge 116. Further, the volume of the
slow-burning portion 180 is continuous and the volume of the
fast-burning portion 182 continuous, i.e., there exists one and
only one volume of each in a single power charge.
[0044] With continuing reference to FIGS. 3 and 4, and further
reference to FIG. 5A, the slow-burning portion 180 volume of the
power charge 116 may define the fast-burning portion 182 volume of
the power charge 116 such that the fast-burning portion 182 volume
is a chamber formed within the slow-burning portion 180 volume. For
example, as in the exemplary power charge(s) shown in FIGS. 3 and
4, the cylindrically shaped power charge 116 may include the
slow-burning portion 180 volume formed as an elongate annular
member. The fast-burning portion 182 volume may be the open inner
area of the annulus, i.e., the chamber formed within the
slow-burning portion 180 volume, defined and bounded by an inner
annulus surface 189. The fast-burning energetic material may be
filled, packed, inserted, etc. in the chamber. Alternatively, the
fast-burning energetic material may be formed as a core of the
power charge 116 such that the fast-burning energetic material and
the slow-burning energetic material are arranged together and
formed into the power charge 116 without discrete or delineated
portions. The chamber, or the fast-burning portion 182 volume,
generally, may extend along any length within the slow-burning
portion 180 volume including all the way therethrough, or may
otherwise be formed by any technique to occupy any particular
volume, of any particular profile or configuration, consistent with
this disclosure.
[0045] Further, in various alternative embodiments, the power
charge 116 may have any geometry, cross-sectional profile,
arrangement, and the like including the incorporation and
configuration of the slow-burning portion 180 volume and the
fast-burning portion 182 volume consistent with this disclosure and
as particular applications may dictate.
[0046] FIG. 5A illustrates the end of the power charge 116 shown in
FIG. 4 designed to cause ignition portion 188 to be disposed
adjacent the initiator 118 when power charge 116 is properly
inserted in power charge cavity 114, according to an embodiment.
FIG. 5B is a cross-sectional view of the power charge 116 shown in
FIG. 4 showing the relationship between the slow-burning portion
180 and the fast-burning portion 182. FIG. 5C is a cross-sectional
view of the power charge 116 shown in FIG. 4 showing a portion of
thereof having only slow-burning energetic material, i.e., lacking
fast-burning portion 182.
[0047] Ignition of the initiator 118 adjacent ignition portion 188
will initiate combustion of both the slow-burning portion 180 and
the fast-burning portion 182 of the power charge 116 shown in FIG.
4. The different burn rates of the portion 180 and the portion 182
results in combustion of the fast-burning portion 182 occurring
much more quickly than the combustion of the portion 180. The fast
and slow-burn rates differing by a factor in the range of about a
hundred to several hundred times, portion 182 will be completely
consumed in the time that only a small portion of portion 180 has
been consumed. As with any energetic material used in a power
charge, once consumed, the volume previously occupied by the
energetic material is now occupied primarily by gas. The volume
previously occupied by the energetic material becomes part of the
path for pressurized gas to access the expansion chamber 128. Thus,
the relatively fast combustion of the fast-burning portion 182
quickly opens a path through the power charge 116 that would have
taken substantially longer to open if the combustion of the
slow-burning portion 180 were relied upon to open the path. Once
opened, the path for pressurized gas formerly occupied by
fast-burning portion 182 causes the combustion gases and, thus, gas
pressure from the combustion of slow-burning portion 180 to be
conveyed past the unreacted portion of the slow-burning portion
180.
[0048] Thus, the current problem of pressure build-up being
delivered as an excessively strong single pulse to the gas divertor
channel is avoided with the provision of a fast-burning portion 182
through some or all of the slow-burning portion 180. Rather,
depending upon the different combustion rates between the
slow-burning portion and fast-burning portion 182 of the power
charge 116, only a relatively small pressure build-up will occur
prior to a path being opened to the gas diverter channel 134 or
other access route to the area in the wellbore tool where
mechanical work is achieved, e.g., expansion chamber 128. In the
embodiments shown in FIG. 2 and FIG. 3, the axial force exerted on
outer sleeve 120 will be increased relatively gradually after
fast-burning portion 182 is fully consumed, thus enabling a simple
and economical means of achieving slow set delivery of force by
setting tool 100 on tool 102.
[0049] As illustrated in FIG. 3, FIG. 4 and FIG. 5A, the power
charge 116 may further include an indentation 140 adjacent the
initiator 118 and/or initiator holder 138. By providing a slight
offset between initiator 118 and the surface of power charge 116,
the indentation 140 is configured to increase the reliability that
the initiator 118 initiates the combustion of the power charge 116.
Further, indentation 140 may be filled or lined with a booster
charge (not shown), the chemical makeup of the booster charge being
more sensitive to initiation than the chemical makeup of either or
both the fast-burning and slow-burning portions of the power charge
116.
[0050] Although the figures, particularly FIG. 4 and FIG. 5B, show
the fast-burning portion 182 as approximately coaxial to the
remainder of the power charge 116, this geometry is one option.
FIG. 6 illustrates an embodiment where the fast-burning portion 182
is radially offset from the axis of the power charge 116. The
geometry of FIG. 6 may be selected to decrease the distance between
the fast-burning portion 182 and the gas diverter channel 134 or
other access route to the area in the wellbore tool where
mechanical work is achieved is located. The possibility exists that
the fast-burning portion 182 may be completely consumed but the
reaction still needs to consume the slow-burning portion 180 to
complete the path for pressurized gas to the gas diverter channel
134. The geometry of FIG. 6 can be one solution to this issue.
Another solution to this issue is to have the fast-burning portion
182 approach very close to or even meet the distal end 184 of power
charge 116. The fast consumption of the fast-burning portion 182
relative to the slow-burning portion 180 will, thus, result in a
path through the entirety (or substantially the entirety) of the
power charge 116 before a substantial portion of the portion 180
has been consumed. For example, in an exemplary embodiment in which
the slow burning portion 180
[0051] In the exemplary embodiment illustrated in FIG. 3, the
single use setting tool 100 may include a shear element 152
connected to the inner piston 104 and the outer sleeve 120. The
shear element 152 may be configured to prevent the axial sliding of
the outer sleeve 120 relative to the inner piston 104. The shear
element 152 allows the axial sliding of the outer sleeve 120
relative to the inner piston 104 subsequent to the formation of the
combustion gas in the expansion chamber 128 exceeding a threshold
pressure. That is, once the gas pressure in expansion chamber 128
reaches a threshold pressure, the force pushing axially against
outer sleeve 120 will cause failure of shear pin 152. The outer
sleeve 120 will then be free to move axially relative to inner
piston 104. In the context of the power charge 116 embodiments
described herein, the force to shear the shear element 152 can be
set higher than the greatly reduced initial force from burning of
energetic material prior to a path to the gas diverter channel 134
being opened. Thus, the shear element 152 prevents the initial gas
build-up from having any effect on the ultimate work performed by
the wellbore tool.
[0052] The exemplary single use setting tool 100 may also include a
gas bleed 154 positioned such that after gas pressure in the
expansion chamber 128 has moved the outer sleeve 120 and inner
piston 104 relative to one another to a point where gas bleed 154
moves past a first seal assembly 148, the gas bleed 154 may vent
excess pressures in the expansion chamber 128 and the central bore
126 of the outer sleeve 120, through the body 110 of the outer
sleeve 120. A second seal assembly 150 seals the outer sleeve 120
to the inner piston 104 such that the expansion chamber 128 is
sealed on both ends and gas pressure may build up therein.
[0053] In an embodiment, either or both the power charge 116 and
the power charge cavity 114 may have a gas pressure path formed
therein before any combustion is initiated. FIG. 7 shows a side
cross-sectional detail view of the power charge cavity 114 portion
of a setting tool 100. The setting tool 100 of FIG. 7 includes one
or more grooves 142 disposed at an intersecting surface 144 between
the power charge 116 and the annular wall 112 of cavity 114. The
one or more grooves 142 may extend axially along a substantial
portion of the intersecting surface 144. The groove 142 is
configured to allow gas pressure communication between the
proximal, initiation end 186 of power charge 116, where combustion
begins, and the expansion chamber 128 via the gas diverter channel
134.
[0054] The groove 142 may be formed in the power charge 116 or the
annular wall 112 of the setting tool cavity 114. FIG. 7 shows a set
of grooves 142 present in the annular wall 112 of the power charge
cavity 114. A standard, cylindrical power charge 116 disposed in
the power charge cavity of 114 of FIG. 7 will have a gas pressure
path, in the form of grooves 142, linking the initiation end 186 of
the power charge 116 to the expansion chamber 128 via the gas
diverter channel 134. The power charge shown in FIG. 8 does not
have a standard cylindrical shape. Rather, FIG. 8 shows a power
charge 116 in which two axial grooves 142' have been formed into
the outer surface thereof. The power charge 116 shown in FIG. 8
inserted in the power charge cavity 114 of tool 100 will have a gas
pressure path, in the form of grooves 142', linking the initiation
end 186 of the power charge 116 to the expansion chamber 128 via
the gas diverter channel 134. Grooves 142 and 142' may also be
formed in both the annular wall 112 of the power charge cavity 114
and the power charge 116 itself.
[0055] Thus, grooves 142 and/or 142' provide an immediate or far
earlier gas pressure path from the combusting initiation end 186 of
the power charge 116 to the gas diverter channel 134. Like the
fast-burning portion 182, the grooves 142, 142' prevent a large
build-up of gas pressure in cavity 114 that is blocked from
reaching gas diverter channel 134 by unburned power charge 116.
Thus, the current problem of pressure build-up being delivered as a
single pulse may be reduced with grooves 142, 142'. Rather, the
axial force exerted on outer sleeve 120 may be increased relatively
gradually, over the course of seconds (or any particular amount of
time as applications dictate and the design of the cavity 114, the
power charge 116, and the gas diverter channels 134, among other
things, may accomplish), thus enabling a simple and economical
means of achieving slow set delivery of force in a wellbore
tool.
[0056] The present disclosure, in various embodiments,
configurations and aspects, includes components, methods,
processes, systems and/or apparatus substantially developed as
depicted and described herein, including various embodiments,
sub-combinations, and subsets thereof. Those of skill in the art
will understand how to make and use the present disclosure after
understanding the present disclosure. The present disclosure, in
various embodiments, configurations and aspects, includes providing
devices and processes in the absence of items not depicted and/or
described herein or in various embodiments, configurations, or
aspects hereof, including in the absence of such items as may have
been used in previous devices or processes, e.g., for improving
performance, achieving ease and/or reducing cost of
implementation.
[0057] The phrases "at least one", "one or more", and "and/or" are
open-ended expressions that are both conjunctive and disjunctive in
operation. For example, each of the expressions "at least one of A,
B and C", "at least one of A, B, or C", "one or more of A, B, and
C", "one or more of A, B, or C" and "A, B, and/or C" means A alone,
B alone, C alone, A and B together, A and C together, B and C
together, or A, B and C together.
[0058] In this specification and the claims that follow, reference
will be made to a number of terms that have the following meanings.
The terms "a" (or "an") and "the" refer to one or more of that
entity, thereby including plural referents unless the context
clearly dictates otherwise. As such, the terms "a" (or "an"), "one
or more" and "at least one" can be used interchangeably herein.
Furthermore, references to "one embodiment", "some embodiments",
"an embodiment" and the like are not intended to be interpreted as
excluding the existence of additional embodiments that also
incorporate the recited features. Approximating language, as used
herein throughout the specification and claims, may be applied to
modify any quantitative representation that could permissibly vary
without resulting in a change in the basic function to which it is
related. Accordingly, a value modified by a term such as "about" is
not to be limited to the precise value specified. In some
instances, the approximating language may correspond to the
precision of an instrument for measuring the value. Terms such as
"first," "second," "upper," "lower," etc. are used to identify one
element from another, and unless otherwise specified are not meant
to refer to a particular order or number of elements.
[0059] As used herein, the terms "may" and "may be" indicate a
possibility of an occurrence within a set of circumstances; a
possession of a specified property, characteristic or function;
and/or qualify another verb by expressing one or more of an
ability, capability, or possibility associated with the qualified
verb. Accordingly, usage of "may" and "may be" indicates that a
modified term is apparently appropriate, capable, or suitable for
an indicated capacity, function, or usage, while taking into
account that in some circumstances the modified term may sometimes
not be appropriate, capable, or suitable. For example, in some
circumstances an event or capacity can be expected, while in other
circumstances the event or capacity cannot occur--this distinction
is captured by the terms "may" and "may be."
[0060] As used in the claims, the word "comprises" and its
grammatical variants logically also subtend and include phrases of
varying and differing extent such as for example, but not limited
thereto, "consisting essentially of" and "consisting of." Where
necessary, ranges have been supplied, and those ranges are
inclusive of all sub-ranges therebetween. It is to be expected that
variations in these ranges will suggest themselves to a
practitioner having ordinary skill in the art and, where not
already dedicated to the public, the appended claims should cover
those variations.
[0061] The terms "determine", "calculate" and "compute," and
variations thereof, as used herein, are used interchangeably and
include any type of methodology, process, mathematical operation or
technique.
[0062] The foregoing discussion of the present disclosure has been
presented for purposes of illustration and description. The
foregoing is not intended to limit the present disclosure to the
form or forms disclosed herein. In the foregoing Detailed
Description for example, various features of the present disclosure
are grouped together in one or more embodiments, configurations, or
aspects for the purpose of streamlining the disclosure. The
features of the embodiments, configurations, or aspects of the
present disclosure may be combined in alternate embodiments,
configurations, or aspects other than those discussed above. This
method of disclosure is not to be interpreted as reflecting an
intention that the present disclosure requires more features than
are expressly recited in each claim. Rather, as the following
claims reflect, the claimed features lie in less than all features
of a single foregoing disclosed embodiment, configuration, or
aspect. Thus, the following claims are hereby incorporated into
this Detailed Description, with each claim standing on its own as a
separate embodiment of the present disclosure.
[0063] Advances in science and technology may make variations and
substitutions possible that are not now contemplated by reason of
the imprecision of language; these variations should be covered by
the appended claims. This written description uses examples to
disclose the method, machine and computer-readable medium,
including the best mode, and also to enable any person of ordinary
skill in the art to practice these, including making and using any
devices or systems and performing any incorporated methods. The
patentable scope thereof is defined by the claims, and may include
other examples that occur to those of ordinary skill in the art.
Such other examples are intended to be within the scope of the
claims if they have structural elements that do not differ from the
literal language of the claims, or if they include structural
elements with insubstantial differences from the literal language
of the claims.
* * * * *