This invention relates, in general, to equipment utilized in conjunction with operations performed in subterranean wells and, in particular, to a downhole actuator apparatus having a chemically activated trigger.
Without limiting the scope of the present invention, its background will be described in relation to setting packer assemblies, as an example.
In the course of completing a subterranean well, one or more packer assemblies are commonly installed at various locations within the well to isolate the wellbore annulus from the production tubing. Typically, a packer assembly incorporates a slip arrangement for securing the packer against the casing or liner wall and an expandable elastomeric element for creating a reliable hydraulic seal to isolate the annulus. In this manner, the packer assemblies are capable of supporting the production tubing and other completion equipment in the well and providing a seal between the outside of the production tubing and the inside of the well casing to block movement of fluids in the annulus to, for example, isolate a production interval.
Such production packers as well as other types of downhole tools may be run downhole on production tubing to a desired depth in the wellbore. Certain production packers may be set hydraulically by creating a pressure differential across a setting piston. For example, this pressure differential may be generated by creating a pressure differential between the fluid within the production tubing and the fluid within the wellbore annulus. This pressure differential shifts the setting piston to actuate the production packer into sealing and gripping engagement with the wellbore casing or liner. To prevent premature actuation of the setting piston, an actuator assembly including a rupture disc may be positioned in the flow path between the pressure differential. When it is desired to set the production packer, sufficient pressure may be applied to burst the rupture disc, thereby allowing the actuator assembly to operate and providing a fluid path for the differential pressure to operate on the setting piston.
As operators increasingly pursue more complicated completions in deep water offshore wells, highly deviated wells and extended reach wells, the use of rupture discs to create a downhole pressure barrier has become more difficult due to the lack of pressure headroom between the downhole hydrostatic pressure and the burst or collapse pressure of the downhole tubulars. Accordingly, a need has arisen for a downhole actuator assembly operable to selectively prevent and allow the application of a pressure differential to a hydraulically set downhole tool. A need has also arisen for such a downhole actuator assembly that is operable for use in complicated completions in deep water offshore wells, highly deviated wells and extended reach wells.
The present invention disclosed herein is directed to an improved downhole actuator assembly operable to selectively prevent and allow the application of a pressure differential to a hydraulically set downhole tool. In addition, the downhole actuator assembly of the present invention is operable for use in complicated completions in deep water offshore wells, highly deviated wells and extended reach wells.
In one aspect, the present invention is directed to a downhole actuator apparatus that has a body defining first and second chambers and a piston slidably disposed in the body that is selectively moveable between first and second positions. A barrier is disposed in the body to selectively separate the first and second chambers. A fluid is disposed in the first chamber between the barrier and the piston. A control system that is at least partially disposed within the body is operable to generate an output signal responsive to receipt of a predetermined input signal. The output signal is operable to create a failure of the barrier such that at least a portion of the fluid flows from the first chamber to the second chamber and the piston moves from the first position to the second position.
In one embodiment, the body defines a fluid path between two pressure regions and the piston is sealably disposed in the fluid path to maintain a pressure differential between the two pressure regions when the piston is in the first position. In this embodiment, the piston may include a piston area that is exposed to pressure from at least one of the pressure regions to bias the piston from the first to the second position. Alternatively or additionally, the piston may be biased toward the second position from the first position by a spring. In another embodiment, the fluid in the first chamber prevents the piston from moving to the second position until failure of the barrier. In this embodiment, fluid may be one or more substantially incompressible fluids, one or more compressible fluids or may be a combination of one or more substantially incompressible fluids and one or more compressible fluids.
In one embodiment, the barrier may be a disc member. In another embodiment, the control system may include a signal detector, a control circuit and a trigger, such that upon receipt of the predetermined input signal by the signal detector, the control circuit activates the trigger to create the failure of the barrier. In this embodiment, the predetermined input signal may be a surface generated signal such as a wireless signal, an electromagnetic signal, an acoustic signal, a pressure signal, an electrical signal, an optical signal or the like. Alternatively, the predetermined input signal may be a downhole generated signal such as a signal from a timer, a downhole sensor or the like. Also, in this embodiment, the output signal may be heat generated by the trigger that melts at least a portion of the barrier, pressure generated by the trigger that shifts a piercing assembly that forms an opening through the barrier, a chemical jet generated by the trigger that makes an opening in the barrier or the like. In this and other embodiments, the trigger may include an energetic material such as pyrotechnic compositions, flammable solids, explosives, thermites and the like.
In another aspect, the present invention is directed to a downhole actuator apparatus that has a body defining first and second chambers and a fluid path between two pressure regions. A piston is slidably disposed in the body and selectively moveable between first and second positions. The piston is sealably disposed in the fluid path to maintain a pressure differential between the two pressure regions when the piston is in the first position.
A barrier is disposed in the body to selectively separate the first and second chambers. A fluid is disposed in the first chamber between the barrier and the piston. The fluid is operable to selectively prevent the piston from moving to the second position. A control system is disposed at least partially within the body. The control system includes a signal detector, a control circuit and a thermite trigger, such that upon receipt of a predetermined input signal by the signal detector, the control circuit activates the thermite trigger to create a failure of the barrier enabling at least a portion of the fluid to flow from the first chamber to the second chamber and the piston to move from the first position to the second position, thereby allowing fluid communication between the two pressure regions.
In a further aspect, the present invention is directed to a downhole actuator apparatus that includes a body defining a fluid path between two pressure regions. A barrier is disposed in the fluid path to maintain a pressure differential between the two pressure regions. A control system is at least partially disposed within the body. The control system includes a signal detector, a control circuit and a thermite trigger, wherein upon receipt of a predetermined input signal by the signal detector, the control circuit activates the thermite trigger to create a failure of the barrier, thereby allowing fluid communication between the two pressure regions.
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:
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.
Referring initially to
In each of these cases, the actuators are used to operate the corresponding well tool by controlling fluid communication between pressure regions in the well. For example, when the pressure regions are blocked from one another, the well tool is in one position and when there is fluid communication between the pressure regions, the well tool is actuated to another position. The pressure regions could be, for example, an interior flow passage 44 of tubular string 12 and an annulus 46 formed radially between tubular string 12 and casing 14. In another example, the pressure regions could be interior flow passage 44 of tubular string 12 and an interior chamber within a sample chamber 36, 38 or the pressure regions could be two chambers with a sample chamber 36, 38 such as a nitrogen charged chamber and an atmospheric chamber. As a further example, the pressure regions could be sections of a control line leading from the surface to a well tool, sections of a control line between well tools or other similar control line configuration. Accordingly, it is to be understood by those skilled in the art that the actuators of the present invention may be used to operate the corresponding well tools by controlling fluid communication between any two pressure regions in the well without departing from the principles of the present invention.
Even though
Referring now to
Slidably and sealingly disposed within housing member 56 is a piston 66 that initially blocks communication between ports 60, 62, as best seen in
Securably and sealingly positioned between housing member 54 and housing member 56 is a barrier assembly 74 that includes a barrier 76 and a support assembly 78 having a fluid passageway 80 defined therethrough. Barrier 76 initially prevents fluid 70 from escaping from chamber 72 into a chamber 82 of housing member 54. Barrier 76 is depicted as a disk member and is preferably formed from a metal but could alternatively be made from a plastic, a composite, a glass, a ceramic, a mixture of these materials, or other material suitable for initially containing fluid 70 in chamber 72 but failing in response to an output signal as described below.
Positioned within housing member 54 is a control system 84 that includes numerous components that cooperate together to receive and process a predetermined input signal and to generate an output signal that creates a failure of barrier 76. For example, control system 84 includes a signal detector such as a pressure sensor, a strain sensor, a hydrophone, an antenna or any other type of signal detector which is capable of receiving the predetermined input signal, which may be in the form of a wireless signal such as an acoustic signal, pressure pulses, electromagnetic telemetry or the like. Alternatively, the signal detector could be hard wired to the surface and operable to receive the predetermined input signal in the form of an electrical signal, an optical signal or the like. As another alternatively, the signal detector may communicate with other downhole devices which may be internal or external to housing assembly 52 such as a timer, a downhole sensor or the like that generates the predetermined input signal.
The signal detector may include or be in communication with a control circuit that interprets the input signal, for example, by digitally decoding the input signal, and that determines whether actuator 50 should be operated. The control circuit is preferably an electronic circuit including various components such as a microprocessor, a digital signal processor, random access member, read only member and the like that are programmed or otherwise operable to recognize the predetermined input signal and to determine whether actuator 50 should be operated. Control system 84 also includes a downhole power supply operable to provide the required power to the other elements of control system 84. Preferably, the power supply is in the form of one or more batteries, however, other types of power supplies may alternatively be used without departing from the principles of the present invention. Control system 84 may also include timing devices to delay or control the time period between receipt of the predetermined input signal and the generation of the output signal.
Control system 84 further includes an output signal generator or trigger depicted in
Fe2O3+2Al→2Fe+Al2O3+Heat
Use of chemical element 88 that produces 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. Chemical element 88 may also include a binder material to hold the included chemicals together, including, for example, TEFLON™, VITON™, PBAN (polybutadiene acrylonitrile copolymer), HTPB (hydroxyl-terminated polybutadiene), epoxy and the like.
In the illustrated embodiment, ignition agent 90 is connected to the control circuit via an electrical cable 94 so that, when it is determined that actuator 50 should be operated, the control circuit supplies electrical current to ignition agent 90. Ignition agent 90 is preferably a metal burning fuse such as a magnesium fuse which is activated by the electrical current. Metal fuses are preferred as metals burn without releasing cooling gases and can burn at extremely high temperatures. Magnesium fuses are most preferred due to the reactive nature of magnesium and the temperature at which magnesium burns which is sufficiently high to ignite chemical element 88. Alternatively, a nichrome wire such as a NiCr60 wire, may be used to directly ignite chemical element 88. As another alternative, a nichrome wire may be used in an ignition train to ignite a metal burning fuse which in turn ignites chemical element 88. In this case, both the nichrome wire and the metal burning fuse may be considered to be ignition agent 90.
In the illustrated embodiment, nozzle 92 is designed to focus the heat and molten materials created in the thermite reaction into a hot jet that is directed towards barrier 76. The hot jet causes a focused hot spot on barrier 76 resulting in the desired failure of barrier 76. It is noted that the mode of failure of barrier 76 may including penetrating, melting, combustion, ignition, weakening or other degradation of barrier 76.
Even though control system 84 has been described as being positioned within housing member 54, those skilled in the art will recognize that certain elements of control system 84 could alternatively be positioned outside of actuator 50 including the signal detector, the control circuit and the power supply, without departing from the principle of the present invention. For example, one or more of these components could be located within the well tool that is to be actuated by actuator 50 or could be located in other tools that are coupled to actuator 50. For the purposes of the present invention, it is only relevant that the output signal generator is positioned sufficiently proximate to barrier 76 to cause the desired failure.
In operation, the signal detector of control system 84 receives the predetermined input signal and the control circuit processes the predetermined input signal to verify the signal. If the control circuit determines that actuator 50 should be operated, electrical power is supplied from the power supply to ignition agent 90 to initiate the chemical reaction in chemical element 88. The chemical reaction causes barrier 76 to fail, creating opening 96 therethrough, as best seen in
Referring now to
Securably and sealingly positioned between housing member 154 and housing member 156 is a barrier assembly 174 that includes a barrier 176 and a support assembly 178 having a fluid passageway 180 defined therethrough. Barrier 176 initially prevents fluid 170 from escaping from chamber 172 into a chamber 182 of housing member 154. Positioned within housing member 154 is a control system 184 that includes a signal detector, a control circuit, a power supply, optional timing devices and an output signal generator or trigger depicted in
In an exemplary embodiment, chemical element 188 may comprises a solid propellant such as nitrocellulose plasticized with nitroglycerin or various phthalates and inorganic salts suspended in a plastic or synthetic rubber and containing a finely divided metal. Chemical element 188 may comprise inorganic oxidizers such as ammonium and potassium nitrates and perchlorates such as potassium perchlorate. It should be appreciated, however, that substances other than propellants may be utilized without departing from the principles of the present invention, including other explosives, pyrotechnics, flammable solids or the like. In the illustrated embodiment, ignition agent 190 is connected to the control circuit via an electrical cable 196 so that, when it is determined that actuator 150 should be operated, the control circuit supplies electrical current to ignition agent 190.
In operation, the signal detector of control system 184 receives the predetermined input signal and the control circuit processes the predetermined input signal to verify the signal. If the control circuit determines that actuator 150 should be operated, electrical power is supplied from the power supply to ignition agent 190 to initiate the chemical reaction in chemical element 188. The chemical reaction causes piercing element 192 to move to the right piecing barrier 176, as best seen in
Referring now to
Securably and sealingly positioned between housing member 254 and housing member 256 is a barrier assembly 274 that includes a barrier 276 and a support assembly 278 having a fluid passageway 280 defined therethrough. Barrier 276 initially prevents fluid 270 from escaping from chamber 272 into a chamber 282 of housing member 254. Positioned within housing member 254 is a control system 284 that includes a signal detector, a control circuit, a power supply, optional timing devices and an output signal generator or trigger depicted in
In operation, the signal detector of control system 284 receives the predetermined input signal and the control circuit processes the predetermined input signal to verify the signal. If the control circuit determines that actuator 250 should be operated, electrical power is supplied from the power supply to ignition agent 290 via electrical cable 294 to initiate the chemical reaction in chemical element 288. The chemical reaction causes barrier 276 to fail, as best seen in
Referring now to
In operation, the signal detector of control system 384 receives the predetermined input signal and the control circuit processes the predetermined input signal to verify the signal. If the control circuit determines that actuator 350 should be operated, electrical power is supplied from the power supply to ignition agent 390 via electrical cable 394 to initiate the chemical reaction in chemical element 388. The chemical reaction causes barrier 376 to fail, as best seen in
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.