FIELD OF THE INVENTION
[0001] This invention relates, in general, to equipment utilized in conjunction with operations
performed in subterranean wells and, in particular, to remote actuated downhole pressure
barriers for use in subterranean wells and methods for use of same.
BACKGROUND OF THE INVENTION
[0002] Without limiting the scope of the present invention, its background is described
with reference to using dissolvable members in plugging devices, as an example.
[0003] It is well known in the completion and production arts to install and retrieve plugs
in subterranean wells via intervention into the wells. For example, when it is desired
to plug a well, a plugging device may be latched in an internal profile of a tubular
string using a conveyance such as a slickline, a wireline, a coiled tubing or the
like. When it is later desired to produce or otherwise access the well, the plugging
device may be retrieved using the appropriate conveyance.
[0004] It has been found, however, that in some well configurations, such as certain deviated
or horizontal wells, the use of such conveyances may not be desirable or feasible
for installation or retrieval of a plugging device. In such well configurations, the
plugging device may be installed at the desired location within the tubular string
at the surface then conveyed into the well as part of the tubular string in which
it is installed. Once installed, such plugging devices have been remotely actuated
using a variety of techniques such as dissolving all or part of the plugging device
using a chemical solution, ultraviolet light, a nuclear source or an explosive. For
example, certain plugging devices have utilized a dispersible plug member that is
dissolvable or otherwise dispersible by contact with fluid, including chemical solutions
or water. In such cases, the member may be initially isolated from contact with the
fluid and then, when it is desired to permit flow through the plugging device, the
fluid is placed in communication with the member, thereby dispersing the member. In
one commonly used plugging device, the dispersible plug member has been constructed
using a mixture of compacted salt and sand. These and other types of plugging devices
have used activation mechanisms including timer-controlled mechanical, hydraulic and
electrical devices as well as wireless communication systems.
[0005] It has been found, however, that conventional dispersible plug members are not suitable
for service over an extended time period and thus cannot operate as pressure barriers.
Accordingly, a need has arisen for a plugging device that is suitable installation
and deployment in a tubular string. A need has also arisen for such a plugging device
that is operable to be remotely actuated. Further, a need has arisen for such a plugging
device that has an extended service life and may therefore operate as a pressure barrier.
SUMMARY OF THE INVENTION
[0006] The present invention disclosed herein is directed to remote actuated downhole pressure
barriers for use in subterranean wells and methods for use of same. The downhole pressure
barrier of the present invention is suitable for installation and deployment in a
tubular string and is operable to be remotely actuated. In addition, the downhole
pressure barrier of the present invention has an extended service life.
[0007] In one aspect, the present invention is directed to a downhole pressure barrier that
is operatively positionable in a subterranean well. The downhole pressure barrier
includes a housing having a flow passage formed therethrough and a plug member positioned
within the flow passage that selectively prevents flow through the flow passage and
allows flow through the flow passage responsive to contact with an activating agent.
At least one retainer assembly supports the plug member within the housing. The retainer
assembly selectively prevents communication between the activating agent and the plug
member. An activating assembly includes a combustible agent that is positioned between
at least a portion of retainer assembly and the plug member. The activating assembly
is operable to create a communication path through the retainer assembly upon combustion
of the combustible agent to allow communication between the activating agent and the
plug member.
[0008] In one embodiment, the plug member may be a mixture of sand and salt. In another
embodiment, the activating agent may be at least one of a wellbore fluid and water.
In this embodiment, the housing may include a fluid chamber operable to contain the
activating agent. In a further embodiment, the combustible agent may be a mixture
of a metal powder and a metal oxide.
[0009] In one embodiment, a seal element is positioned between the retainer assembly and
the housing to prevent fluid flow therebetween. In another embodiment, the retainer
assembly may include a discoidal portion that has a spaced apart relationship with
the plug member. In this embodiment, the combustible agent may be positioned in the
space between the plug member and the discoidal portion of the retainer assembly.
Also in this embodiment, a separator member may be positioned between the combustible
agent and the plug member. The discoidal portion of the retainer assembly and the
separator member may be metallic. In a further embodiment, the activating assembly
may include an ignition agent operably positioned proximate the combustible agent
used to ignite the combustible agent. In addition, the activating assembly may include
an electronic package operable to receive a wireless signal and to send a signal to
the ignition agent.
[0010] In another aspect, the present invention is directed to a downhole pressure barrier
that is operatively positionable in a subterranean well. The downhole pressure barrier
includes a housing having a flow passage formed therethrough. A plug member, formed
from a mixture of sand and salt, is positioned within the flow passage to selectively
prevent flow through the flow passage and allow flow through the flow passage responsive
to contact with an activating agent. At least one retainer assembly supports the plug
member within the housing. The retainer assembly selectively prevents communication
between the activating agent and the plug member. An activating assembly includes
a combustible agent that is integrally formed in the plug member. The activating assembly
is operable to create a communication path through the retainer assembly upon combustion
of the combustible agent to allow communication between the activating agent and the
plug member.
[0011] In a further aspect, the present invention is directed to a downhole pressure barrier
that is operatively positionable in a subterranean well. The downhole pressure barrier
includes a housing having a flow passage formed therethrough. A plug member, formed
from a thermosetting polymer or a polymer matrix, is positioned within the flow passage
to selectively prevent and allow flow through the flow passage. At least one retainer
assembly supports the plug member within the housing. An activating assembly includes
a combustible agent that is integrally formed in the plug member. The activating assembly
is operable to create a communication path through the downhole pressure barrier upon
combustion of the combustible agent.
[0012] In a further aspect, the present invention is directed to a method for remotely actuating
a downhole pressure barrier positioned in a subterranean well. The method includes
receiving a wireless signal at a receiver positioned within the downhole pressure
barrier, generating a activation signal responsive to the received wireless signal,
activating an ignition agent responsive to the activation signal, igniting a combustible
agent with the ignition agent, creating a communication path between an activating
agent and a plug member of the downhole pressure barrier responsive to the combustion
and contacting the plug member with the activating agent to disperse the plug member,
thereby opening a communication path through the downhole pressure barrier.
[0013] The method may also include one or more of sensing a series of pressure fluctuations
via the receiver, activating a magnesium fuse, igniting a mixture of a metal powder
and a metal oxide, contacting the plug member with at least one of a wellbore fluid
and water, contacting a mixture of sand and salt with the activating agent and containing
the activating fluid in a fluid chamber of the downhole pressure barrier.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] For a more complete understanding of the features and advantages of the present invention,
reference is now made to the detailed description of the invention along with the
accompanying figures in which corresponding numerals in the different figures refer
to corresponding parts and in which:
[0015] Figure 1 is a schematic illustration of an offshore oil and gas platform operating
a remote actuated downhole pressure barrier according to an embodiment of the present
invention;
[0016] Figures 2A-2B are cross sectional views of consecutive axial sections of a remote
actuated downhole pressure barrier according to an embodiment of the present invention;
[0017] Figures 3A-3B are cross sectional views of consecutive axial sections of a remote
actuated downhole pressure barrier according to an embodiment of the present invention;
[0018] Figures 4A-4B are cross sectional views of consecutive axial sections of a remote
actuated downhole pressure barrier according to an embodiment of the present invention;
[0019] Figures 5A-5B are cross sectional views of consecutive axial sections of a remote
actuated downhole pressure barrier according to an embodiment of the present invention;
and
[0020] Figures 6A-6B are cross sectional views of consecutive axial sections of a remote
actuated downhole pressure barrier according to an embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0021] While the making and using of various embodiments of the present invention are discussed
in detail below, it should be appreciated that the present invention provides many
applicable inventive concepts, which can be embodied in a wide variety of specific
contexts. The specific embodiments discussed herein are merely illustrative of specific
ways to make and use the invention, and do not delimit the scope of the invention.
[0022] Referring initially to Figure 1, a remote actuated downhole pressure barrier being
operated from an offshore oil and gas platform is schematically illustrated and generally
designated 10. A semi-submersible platform 12 is centered over an offshore oil and
gas formation 14 located below sea floor 16. A subsea conduit 18 extends from deck
20 of platform 12 to wellhead installation 22 including subsea blow-out preventers
24. Platform 12 has a hoisting apparatus 26 and a derrick 28 for raising and lowering
pipe strings such as work string 30.
[0023] A wellbore 32 extends through the various earth strata including formation 14. A
casing 34 is cemented within wellbore 32 by cement 36. The portion of wellbore 32
extending through horizontal portion 38 includes a plurality of perforations 40 that
allow fluid communication between formation 14 and wellbore 32. Work string 30 includes
various tools such as a plurality of sand control screens 42, a remote actuated downhole
pressure barrier 44 and a packer 46. In operation, remote actuated downhole pressure
barrier 44 provides a pressure barrier that allows the operator to set production
and isolation packers as well as pressure test the production tubing.
[0024] In the illustrated embodiment, even though remote actuated downhole pressure barrier
44 has been disposed in a horizontal portion of wellbore 32, it should be understood
by those skilled in the art that the remote actuated downhole pressure barriers of
the present invention are equally well-suited for use in other well configurations
including, but not limited to, inclined wells, wells with restrictions, non-deviated
wells, multilateral wells and the like. As such, use of directional terms such as
"above", "below", "upper", "lower" and the like are used for convenience in referring
to the illustrations. In addition, even though an offshore operation has been depicted
in figure 1, the remote actuated downhole pressure barriers of the present invention
are equally well-suited for use in onshore operations.
[0025] Referring now to figures 2A-2B, therein is representatively illustrated a remote
actuated downhole pressure barrier that is generally designated 100. Barrier 100 includes
a generally tubular housing assembly 102. Housing assembly 102 that includes a top
sub 104 that is securably and sealingly connected to a middle sub 106 by a plurality
of set screws 108 and seal 110. At its lower end, middle sub 106 is securably and
sealingly connected to a bottom sub 112 at threaded connection 114 and by seal 116.
Disposed within middle sub 106 is an inner mandrel 118. Seals 120, 121 provide a sealing
relationship between middle sub 106 and inner mandrel 118. Housing assembly 102 has
a flow passage 122 formed axially therethrough. Even though housing assembly 102 is
shown as being made up of several interconnected portions 104, 106, 112, 118, it is
to be understood that greater or fewer numbers of housing portions may be utilized
in the housing assembly 102 and the portions may be otherwise configured and otherwise
attached to each other without departing from the principles of the present invention.
[0026] Fluid flow through passage 122 is initially blocked by a dispersible plug member
124. Plug member 124 includes a dispersible portion 126 which is initially compacted
within a plug sleeve 128. Plug member 124 is supported within housing assembly 102
by a pair of oppositely disposed retainer assemblies 130, 132. Retainer assembly 130
is sealingly coupled to inner mandrel 118 by a seal 134. Retainer assembly 132 is
sealingly coupled to bottom sub 112 by a seal 136. Retainer assemblies 130, 132 are
axially positioned between lower shoulder 138 of inner mandrel 118 and upper shoulder
140 of bottom sub 112. Retainer assemblies 130, 132 respectively include discoidal
portions 142, 144 that are generally impervious and serve to isolate dispersible portion
126 from contact with any fluid in flow passage 122. Retainer assemblies 130, 132
including discoidal portions 142, 144 are preferable formed from a metal such as a
stainless steel including, but not limited to, a 625 stainless steel.
[0027] In the illustrated embodiment, dispersible portion 126 is a compacted salt and sand
composition which has sufficient compressive strength to resist fluid pressure in
flow passage 122. When an activating agent such a wellbore fluid, water or other fluid,
is permitted to contact dispersible portion 126, however, the salt constituent will
dissolve. This dissolving of the salt constituent significantly reduces the compressive
strength of dispersible portion 126, so that it is no longer able to resist fluid
pressure in flow passage 122.
[0028] Plug member 124 may be dispersed by dissolving dispersible portion 126 or a constituent
part thereof using wellbore fluid in flow passage 122. In certain implementations,
however, a wellbore fluid capable of dispersing plug member 124 may not available,
for example, if the fluid in flow passage 122 is salt-saturated, oil-based or otherwise
incapable of dissolving a constituent part of dispersible portion 126. In the illustrated
embodiment, barrier 100 includes a fluid chamber 146 disposed within inner mandrel
118 and an upper portion of middle sub 106 and is protected from contamination with
other fluids and debris in the well during conveyance by a debris barrier 148. Debris
barrier 148 extends laterally across flow passage 122, thus isolating the fluid in
fluid chamber 146 from contact with any other fluid or debris in flow passage 122
above debris barrier 148. As such, the fluid in fluid chamber 146 is available for
interaction with dispersible portion 126 when desired.
[0029] As representatively illustrated, debris barrier 148 includes a body portion 150 extending
across flow passage 122 and a somewhat enlarged annular-shaped peripheral portion
152 sealingly received between top sub 104 and middle sub 106 of housing assembly
102. Such sealing engagement of debris barrier 148 acts to completely isolate the
fluid in fluid chamber 146 from other fluids in the well. Debris barrier 148 may be
formed from an elastomeric material, however, in certain implementations, debris barrier
148 may alternatively be made of a nonelastomeric material. An elastomeric material
is preferred, however, since applications of fluid pressure are made to flow passage
122 to initiate activation of plug member 124 as described below.
[0030] In the illustrated embodiment, barrier 100 includes an activating assembly that is
operable to create a communication path through retainer assembly 130 to allow communication
between the fluid in fluid chamber 146 and dispersible portion 126. The activating
assembly includes an electronic package and a combustion assembly. The electronic
package includes a pressure sensor 154, a logic module 156, batteries 158 and various
signal and current conductors (not pictured). The combustion assembly includes ignition
agents 160, 162 and combustible agents 164, 166. As illustrated, separator members
168, 170 are positioned respectively between combustible agents 164, 166 and dispersible
portion 126. Separator members 168, 170 are preferable formed from a metal such as
a stainless steel including, but not limited to, a 625 stainless steel. An optional
heat shielding sleeve 172 is positioned between plug member 124 and middle sub 106.
Heat shielding sleeve 172 is preferably formed from a ceramic materials or other material
capable of shielding middle sub 106 from the heat and temperature generated in the
combustion reaction discussed below.
[0031] Pressure sensor 154 is operable to receive and interpret pressure signals sent from
the surface. For example, by applying a predetermined number and sequence of fluid
pressure fluctuations to flow passage 122 via the tubular string at the surface, pressure
sensor 154 receives the signal via the fluid in fluid chamber 146. The pressure signals
are transferred to the fluid in fluid chamber 146 from the fluid in the tubular string
through debris barrier 148. When pressure sensor 154 receives the proper pressure
signature, pressure sensor 154 sends a signal to logic module 156 to begin the activation
process. Even though the signal for initiating the activation of plug member 124 has
been described as a pressure signal received by a pressure sensor, those skilled in
the art will understand the other types of signals both wireless and wired could alternatively
be used including, but not limited to, acoustic signals, electromagnetic signals,
hydraulic signals, electrical signals, optical signals and the like, such signals
being received and interpreted by the corresponding type of receiver.
[0032] Logic module 156 receives the activation signal from pressure sensor 154 and causes
a current to be sent to ignition agents 160, 162. Logic module 156 may include various
controllers, processors, memory components, operating systems, instructions, communication
protocols and the like. As should be understood by those skilled in the art, any of
the functions described with reference to logic module 156 herein can be implemented
using software, firmware, hardware, including fixed logic circuitry or a combination
of these implementations. As such, the term logic module as used herein generally
represents software, hardware or a combination of software and hardware. For example,
in the case of a software implementation, the term logic module represents program
code and/or declarative content, e.g., markup language content that performs specified
tasks when executed on a processing device or devices such as one or more processors
or CPUs. The program code can be stored in one or more computer readable memory devices.
More generally, the functionality of the illustrated logic module may be implemented
as distinct units in separate physical grouping or can correspond to a conceptual
allocation of different tasks performed by a single software program and/or hardware
unit.
[0033] Batteries 158 are used to power the electronic devices within barrier 100 such as
pressure sensor 154 and logic module 156. In addition, batteries 158 are used to provide
suitable current to initiate the combustion of combustible elements 164, 166. Batteries
158 may be of any suitable type such as alkaline batteries that provide sufficient
power and current and are capable of withstanding the temperature in the well environment.
[0034] In the illustrated embodiment, ignition agents 160, 162 are metal burning fuses such
as magnesium fuses which are activated by the electrical current supplied from batteries
158 in response to the activation signal. Metal fuses are preferred as metals burn
without releasing cooling gases and can burn at extremely high temperatures. Magnesium
fuses are most preferred as due to the reactive nature of magnesium and temperature
at which magnesium burn which is sufficiently high to ignite combustible agents 164,
166. Alternatively, a nichrome wire such as a NiCr60 wire, may be used to directly
ignite combustible agents 164, 166. As another alternative, a nichrome wire may be
used in an ignition train to ignite a metal burning fuse which in turn ignites one
of the combustible agents 164, 166. In this case, both the nichrome wire and the metal
burning fuse may be considered to be one of the ignition agents 160, 162.
[0035] Combustible agents 164, 166 are preferable formed from a composition of a metal powder
and a metal oxide that produces an exothermic chemical reaction at high temperature
such as a thermite reaction. The metal powder used in the composition may include
aluminum, magnesium, calcium, titanium, zinc, silicon, boron and the like. The metal
oxide used in the composition may include boron(III) oxide, silicon(IV) oxide, chromium(III)
oxide, manganese(IV) oxide, iron(III) oxide, iron(II, III) oxide, copper(II) oxide,
lead(II, III, IV) oxide and the like. For example, a composition of aluminum and iron(III)
oxide may be used which has a reaction according to the following equation:
[0036]
Fe
2O
3 + 2Al -> 2Fe + Al
2O
3 + Heat
[0037] Use of combustible agents 164, 166 that produce a thermite reaction is advantageous
in the present invention as the reactants are stable at wellbore temperatures but
produce an extremely intense exothermic reaction following ignition. The combination
of the high temperature and the heat generated by the reaction are sufficient to melt
both the metallic separator members 168, 170 and discoidal portions 142, 144 of retainer
assemblies 130, 132. In the illustrated embodiment, this process creates a communication
path through retainer assembly 130 to allow communication between the fluid in fluid
chamber 146 and dispersible portion 126. The fluid in fluid chamber 146 dissolves
the salt in dispersible portion 126 such that the remaining sand component of dispersible
portion 126 lacks sufficient compressive strength to plug flow passage 122. Accordingly,
the sand disintegrates leaving an open bore within plug sleeve 128.
[0038] Referring next to figures 3A-3B, therein is representatively illustrated a remote
actuated downhole pressure barrier that is generally designated 200. Barrier 200 includes
a generally tubular housing assembly 202 that includes a top sub 204 that is securably
and sealingly connected to a middle sub 206 by a plurality of set screws 208 and seal
210. At its lower end, middle sub 206 is securably and sealingly connected to a bottom
sub 212 at threaded connection 214 and by seal 216. Disposed within middle sub 206
is an inner mandrel 218. Seals 220, 221 provide a sealing relationship between middle
sub 206 and inner mandrel 218. Housing assembly 202 has a flow passage 222 formed
axially therethrough.
[0039] Fluid flow through passage 222 is initially blocked by a dispersible plug member
224. Plug member 224 includes a dispersible portion 226 which is initially compacted
within a plug sleeve 228. Plug member 224 is supported within housing assembly 202
by a pair of oppositely disposed retainer assemblies 230, 232. Retainer assembly 230
is sealingly coupled to inner mandrel 218 by a seal 234. Retainer assembly 232 is
sealingly coupled to bottom sub 212 by a seal 236. Retainer assemblies 230, 232 are
axially positioned between lower shoulder 238 of inner mandrel 218 and upper shoulder
240 of bottom sub 212. Retainer assemblies 230, 232 respectively include discoidal
portions 242, 244 that are generally impervious and serve to isolate dispersible portion
226 from contact with any fluid in flow passage 222.
[0040] In the illustrated embodiment, dispersible portion 226 is preferably a compacted
salt and sand composition, as described above. Barrier 200 includes a fluid chamber
246 disposed within inner mandrel 218 and an upper portion of middle sub 206 and is
protected from contamination with other fluids and debris by a debris barrier 248.
Debris barrier 248 includes a body portion 250 extending across flow passage 222 and
a somewhat enlarged annular-shaped peripheral portion 252 sealingly received between
top sub 204 and middle sub 206 of housing assembly 202.
[0041] In the illustrated embodiment, barrier 200 includes an activating assembly that is
operable to create a communication path through retainer assembly 230 to allow communication
between the fluid in fluid chamber 246 and dispersible portion 226. The activating
assembly includes an electronic package and a combustion assembly. The electronic
package includes a pressure sensor 254, a logic module 256, batteries 258 and various
signal and current conductors (not pictured). The combustion assembly includes ignition
agents 260, 262 and combustible agents 264, 266. In the illustrated embodiment, combustible
agents 264, 266 are integrally disposed within dispersible portion 226 such that the
greatest concentration of the combustible agents 264, 266 is located in the two ends
of dispersible portion 226 proximate discoidal portions 242, 244 of retainer assemblies
230, 232. Ignition agents 260, 262 are preferably metal fuses, as described above.
Combustible agents 264, 266 are preferably formed from a composition of a metal powder
and a metal oxide, as described above. An optional heat shielding sleeve 272 is positioned
between plug member 224 and middle sub 206.
[0042] In operation, pressure sensor 254 receives and interprets pressure signals sent from
the surface. When pressure sensor 254 receives the proper pressure signature, pressure
sensor 254 sends a signal to logic module 256 to begin the activation process. Logic
module 256 then causes a current to be sent to ignition agents 260, 262 from batteries
258. The current is used to ignite ignition agents 260, 262 which in turn ignite combustible
agents 264, 266. The combination of the high temperature and the heat generated by
the reaction of combustible agents 264, 266 are sufficient to melt discoidal portions
242, 244 of retainer assemblies 230, 232, which creates a communication path through
retainer assembly 230 to allow communication between the fluid in fluid chamber 246
and dispersible portion 226. The fluid in fluid chamber 246 dissolves the salt in
dispersible portion 226 such that the remaining sand component of dispersible portion
226 lacks sufficient compressive strength to plug flow passage 222. Accordingly, the
sand disintegrates leaving an open bore within plug sleeve 228.
[0043] Referring next to figures 4A-4B, therein is representatively illustrated a remote
actuated downhole pressure barrier that is generally designated 300. Barrier 300 includes
a generally tubular housing assembly 302 that includes a top sub 304 that is securably
and sealingly connected to a middle sub 306 by a plurality of set screws 308 and seal
310. At its lower end, middle sub 306 is securably and sealingly connected to a bottom
sub 312 at threaded connection 314 and by seal 316. Disposed within middle sub 306
is an inner mandrel 318. Seals 320, 321 provide a sealing relationship between middle
sub 306 and inner mandrel 318. Housing assembly 302 has a flow passage 322 formed
axially therethrough.
[0044] Fluid flow through passage 322 is initially blocked by a plug member 324. Plug member
324 includes a removable portion 326 which is initially compacted within a plug sleeve
328. Plug member 324 is supported within housing assembly 302 by a pair of oppositely
disposed retainer assemblies 330, 332. Retainer assembly 330 is sealingly coupled
to inner mandrel 318 by a seal 334. Retainer assembly 332 is sealingly coupled to
bottom sub 312 by a seal 336. Retainer assemblies 330, 332 are axially positioned
between lower shoulder 338 of inner mandrel 318 and upper shoulder 340 of bottom sub
312. Retainer assemblies 330, 332 respectively include discoidal portions 342, 344
that are generally impervious and serve to isolate removable portion 326 from contact
with any fluid in flow passage 322.
[0045] In the illustrated embodiment, removable portion 326 may be a compacted salt and
sand composition, as described above, that is generally uniformly mixed with a combustible
agent 364. In this embodiment, barrier 300 includes a fluid chamber 346 disposed within
inner mandrel 318 and an upper portion of middle sub 306 and is protected from contamination
with other fluids and debris by a debris barrier 348. Debris barrier 348 includes
a body portion 350 extending across flow passage 322 and a somewhat enlarged annular-shaped
peripheral portion 352 sealingly received between top sub 304 and middle sub 306 of
housing assembly 302. Alternatively, removable portion 326 may be substantially completely
formed from a compaction of the combustible agent 364. In this embodiment, fluid chamber
346 and debris barrier 348 are optional.
[0046] In the illustrated embodiment, barrier 300 includes an activating assembly that is
operable to create a communication path through retainer assembly 330 to allow communication
between the fluid in fluid chamber 346 and removable portion 326. The activating assembly
includes an electronic package and a combustion assembly. The electronic package includes
a pressure sensor 354, a logic module 356, batteries 358 and various signal and current
conductors (not pictured). The combustion assembly includes a plurality of ignition
agents, only two of which, ignition agents 360, 362 are shown and combustible agent
364. The ignition agents are preferably metal fuses, as described above. Combustible
agent 364 is preferably formed from a composition of a metal powder and a metal oxide,
as described above. An optional heat shielding sleeve 372 is positioned between plug
member 324 and middle sub 306.
[0047] In operation, pressure sensor 354 receives and interprets pressure signals sent from
the surface. When pressure sensor 354 receives the proper pressure signature, pressure
sensor 354 sends a signal to logic module 356 to begin the activation process. Logic
module 356 then causes a current to be sent to the ignition agents from batteries
358. The current is used to ignite the ignition agents, which in turn ignites combustible
agent 364. The combination of the high temperature and the heat generated by the reaction
of combustible agent 364 is sufficient to melt discoidal portions 342, 344 of retainer
assemblies 330, 332. In those embodiments including fluid chamber 346 and wherein
removable portion 326 includes a salt constituent, a communication path is created
through retainer assembly 330 to allow communication between the fluid in fluid chamber
346 and removable portion 326. The fluid in fluid chamber 346 dissolves the salt in
removable portion 326 such that the remaining sand component of removable portion
326 lacks sufficient compressive strength to plug flow passage 322. Accordingly, the
sand disintegrates leaving an open bore within plug sleeve 328. In those embodiments
wherein removable portion 326 is substantially completely formed from a compaction
of the combustible agent 364, combustion of combustible agent 364 not only melts the
discoidal portions 342, 344 of retainer assemblies 330, 332 but also creates the open
bore within plug sleeve 328.
[0048] Referring next to figures 5A-5B, therein is representatively illustrated a remote
actuated downhole pressure barrier that is generally designated 400. Barrier 400 includes
a generally tubular housing assembly 402 that includes a top sub 404 that is securably
and sealingly connected to a middle sub 406 by a plurality of set screws 408 and seal
410. At its lower end, middle sub 406 is securably and sealingly connected to a bottom
sub 412 at threaded connection 414 and by seal 416. Disposed within middle sub 406
is an inner mandrel 418. Seals 420, 421 provide a sealing relationship between middle
sub 406 and inner mandrel 418. Housing assembly 402 has a flow passage 422 formed
axially therethrough.
[0049] Fluid flow through passage 422 is initially blocked by a plug member 424. Plug member
424 includes a removable portion 426 which is initially positioned within a plug sleeve
428. Plug member 424 is supported within housing assembly 402 by a pair of oppositely
disposed retainer assemblies 430, 432. Retainer assembly 430 is sealingly coupled
to inner mandrel 418 by a seal 434. Retainer assembly 432 is sealingly coupled to
bottom sub 412 by a seal 436. Retainer assemblies 430, 432 are axially positioned
between lower shoulder 438 of inner mandrel 418 and upper shoulder 440 of bottom sub
412. Retainer assemblies 430, 432 respectively include discoidal portions 442, 444
that are generally impervious and serve to isolate removable portion 426 from contact
with any fluid in flow passage 422. In the illustrated embodiment, removable portion
426 is preferably a polymer material such as a thermosetting polymer including, but
not limited to, an epoxy.
[0050] Barrier 400 includes an activating assembly that is operable to create a communication
path through passage 422. The activating assembly includes an electronic package and
a combustion assembly. The electronic package includes a pressure sensor 454, a logic
module 456, batteries 458 and various signal and current conductors (not pictured).
The combustion assembly includes a plurality of ignition agents, only two of which,
ignition agents 460, 462 are shown and combustible agent 464. In the illustrated embodiment,
combustible agent 464 is integrally disposed within removable portion 426 in a substantially
even distribution throughout removable portion 426. The ignition agents are preferably
metal fuses, as described above. Combustible agent 464 is preferably formed from a
composition of a metal powder and a metal oxide, as described above. An optional heat
shielding sleeve 472 is positioned between plug member 424 and middle sub 406.
[0051] In operation, pressure sensor 454 receives and interprets pressure signals sent from
the surface. When pressure sensor 454 receives the proper pressure signature, pressure
sensor 454 sends a signal to logic module 456 to begin the activation process. Logic
module 456 then causes a current to be sent to the ignition agents from batteries
458. The current is used to ignite the ignition agents, which in turn ignites combustible
agent 464. The combination of the high temperature and the heat generated by the reaction
of combustible agent 464 is sufficient to melt discoidal portions 442, 444 of retainer
assemblies 430, 432 as well as the matrix material of removable portion 426 leaving
an open bore within plug sleeve 428.
[0052] Referring next to figures 6A-6B, therein is representatively illustrated a remote
actuated downhole pressure barrier that is generally designated 500. Barrier 500 includes
a generally tubular housing assembly 502 that includes a top sub 504 that is securably
and sealingly connected to a middle sub 506 by a plurality of set screws 508 and seal
510. At its lower end, middle sub 506 is securably and sealingly connected to a bottom
sub 512 at threaded connection 514 and by seal 516. Disposed within middle sub 506
is an inner mandrel 518. Seals 520, 521 provide a sealing relationship between middle
sub 506 and inner mandrel 518. Housing assembly 502 has a flow passage 522 formed
axially therethrough.
[0053] Fluid flow through passage 522 is initially blocked by a plug member 524. Plug member
524 includes a removable portion 526 which is initially positioned within a plug sleeve
528. Plug member 524 is supported within housing assembly 502 by a pair of oppositely
disposed retainer assemblies 530, 532. Retainer assembly 530 is sealingly coupled
to inner mandrel 518 by a seal 534. Retainer assembly 532 is sealingly coupled to
bottom sub 512 by a seal 536. Retainer assemblies 530, 532 are axially positioned
between lower shoulder 538 of inner mandrel 518 and upper shoulder 540 of bottom sub
512. Retainer assemblies 530, 532 respectively include discoidal portions 542, 544
that are generally impervious and serve to isolate removable portion 526 from contact
with any fluid in flow passage 522. In the illustrated embodiment, removable portion
526 is preferably a polymer material such as a thermosetting polymer including, but
not limited to, an epoxy.
[0054] Barrier 500 includes an activating assembly that is operable to create a communication
path through passage 522. The activating assembly includes an electronic package and
a combustion assembly. The electronic package includes a pressure sensor 554, a logic
module 556, batteries 558 and various signal and current conductors (not pictured).
As illustrated, portions of the electronic package are positioned within removable
portion 526. In other implementations, all of the components of the electronic package
could be positioned within removable portion 526. The combustion assembly includes
a plurality of ignition agents, only two of which, ignition agents 560, 562 are shown
and combustible agent 564. In the illustrated embodiment, combustible agent 564 is
integrally disposed within removable portion 526 in a substantially even distribution
throughout removable portion 526. The ignition agents are preferably metal fuses,
as described above. Combustible agent 564 is preferably formed from a composition
of a metal powder and a metal oxide, as described above. An optional heat shielding
sleeve 572 is positioned between plug member 524 and middle sub 506.
[0055] In operation, pressure sensor 554 receives and interprets pressure signals sent from
the surface. When pressure sensor 554 receives the proper pressure signature, pressure
sensor 554 sends a signal to logic module 556 to begin the activation process. Logic
module 556 then causes a current to be sent to the ignition agents from batteries
558. The current is used to ignite the ignition agents, which in turn ignites combustible
agent 564. The combination of the high temperature and the heat generated by the reaction
of combustible agent 564 is sufficient to melt discoidal portions 542, 544 of retainer
assemblies 530, 532 as well as the matrix material of removable portion 526 leaving
an open bore within plug sleeve 528.
[0056] While this invention has been described with reference to illustrative embodiments,
this description is not intended to be construed in a limiting sense. Various modifications
and combinations of the illustrative embodiments as well as other embodiments of the
invention will be apparent to persons skilled in the art upon reference to the description.
It is, therefore, intended that the appended claims encompass any such modifications
or embodiments.
1. A downhole pressure barrier operatively positionable in a subterranean well, the downhole
pressure barrier comprising:
a housing having a flow passage formed therethrough; a plug member positioned within
the flow passage that selectively prevents flow through the flow passage and allows
flow through the flow passage responsive to contact with an activating agent;
at least one retainer assembly supporting the plug member within the housing, the
retainer assembly selectively preventing communication between the activating agent
and the plug member; and
an activating assembly including a combustible agent positioned between at least a
portion of the retainer assembly and the plug member, the activating assembly operable
to create a communication path through the retainer assembly upon combustion of the
combustible agent to allow communication between the activating agent and the plug
member.
2. A downhole pressure barrier according to claim 1 wherein the activating agent further
comprises at least one of a wellbore fluid and water.
3. A downhole pressure barrier according to claim 1 or 2 wherein the retainer assembly
includes a discoidal portion that has a spaced apart relationship with the plug member.
4. A downhole pressure barrier according to any one of the preceding claims wherein the
combustible agent further comprises a mixture of a metal powder and a metal oxide.
5. A downhole pressure barrier according to any one of the preceding claims wherein the
activating assembly further comprises an ignition agent operably positioned proximate
the combustible agent and an electronic package operable to receive a wireless signal
and send a signal to the ignition agent.
6. A downhole pressure barrier according to any one of the preceding claimswherein the
housing further comprises a fluid chamber operable to contain the activating agent.
7. A downhole pressure barrier operatively positionable in a subterranean well, the downhole
pressure barrier comprising:
a housing having a flow passage formed therethrough; a plug member positioned within
the flow passage that selectively prevents and allows flow through the flow passage;
at least one retainer assembly supporting the plug member within the housing; and
an activating assembly including a combustible agent that is integrally formed in
the plug member, the activating assembly operable to create a communication path through
the retainer assembly upon combustion of the combustible agent.
8. A downhole pressure barrier according to any one of the preceding claims wherein the
plug member further comprises a mixture of sand and salt.
9. a downhole pressure barrier according to any preceding claims wherein the plug member
consists essentially of the combustible agent.
10. A downhole pressure barrier according to any one of the preceding claims wherein the
combustible agent further comprises a mixture of a metal powder and a metal oxide.
11. A downhole pressure barrier according to any one of the preceding claims wherein the
activating assembly further comprises an ignition agent operably positioned proximate
the combustible agent and an electronic package operable to receive a wireless signal
from a surface source and send a signal to the ignition agent.
12. A downhole pressure barrier according to any one of the preceding claims wherein the
housing further comprises a fluid chamber operable to contain an activating agent.
13. A method for remotely actuating a downhole pressure barrier positioned in a subterranean
well, the method comprising:
receiving a wireless signal at a receiver positioned within the downhole pressure
barrier;
generating an activation signal responsive to the received wireless signal;
activating an ignition agent responsive to the activation signal;
igniting a combustible agent with the ignition agent;
creating a communication path between an activating agent and a plug member of the
downhole pressure barrier responsive to the combustion; and
contacting the plug member with the activating agent to disperse the plug member,
thereby opening a communication path through the downhole pressure barrier.
14. A method according to claim 13 wherein receiving a wireless signal at a receiver positioned
within the downhole pressure barrier further comprises sensing a series of pressure
fluctuations via the receiver.
15. A method according to any one of claims 13 or 14 further comprising containing the
activating fluid in a fluid chamber of the downhole pressure barrier.