Not applicable.
After a wellbore has been drilled through a subterranean formation, the wellbore may be cased by inserting lengths of pipe (“casing sections”) connected end-to-end into the wellbore. Threaded exterior connectors known as casing collars may be used to connect adjacent ends of the casing sections at casing joints, providing a casing string including casing sections and connecting casing collars that extends from the surface towards the bottom of the wellbore. The casing string may then be cemented into place to secure the casing string within the wellbore.
In some applications, following the casing of the wellbore, a wireline tool string may be run into the wellbore as part of a “plug-n-perf” hydraulic fracturing operation. The wireline tool string may include a perforating gun for perforating the casing string at a desired location in the wellbore, a downhole plug that may be set to couple with the casing string at a desired location in the wellbore, and a setting tool for setting the downhole plug. In certain applications, once the downhole plug has been set and the casing string has been perforated by the perforating gun, a ball or dart may be pumped into the wellbore for landing against the set downhole plug, thereby isolating the portion of the wellbore extending uphole from the set downhole plug. With this uphole portion of the wellbore isolated, the formation extending about the perforated section of the casing string may be hydraulically fractured by fracturing fluid pumped into the wellbore.
An embodiment of a method for perforating tubular strings positioned in wellbores comprises (a) lowering a first tool string into a first wellbore, the tool string comprising a first perforating gun and a gun switch configured to detonate the first perforating gun, (b) detonating the first perforating gun in response to transmitting a first gun firing signal from a control system to the gun switch, (c) retrieving the tool string from the first wellbore following (c), (d) lowering a second tool string comprising the gun switch used in the first tool string and a second perforating gun into at least one of the first wellbore and a second wellbore that is different from the first wellbore following (d), and (e) detonating the second perforating gun of the second tool string in response to transmitting a second gun firing signal from the control system to the gun switch. In some embodiments, the method comprises (f) with the first tool string lowered into the first wellbore, transmitting an enabling signal from the control system to a safety switch positioned in a switch receptacle of a safety sub of the tool string to close the safety switch and thereby permit signal communication between the control system and the gun switch, wherein the safety switch is isolated from fluid pressure external of the safety sub. In some embodiments, the method comprises (f) with the first tool string lowered into the first wellbore, transmitting a setting tool firing signal from the control system to a setting tool switch positioned in a switch receptacle of a setting tool of the first tool string to set a downhole plug of the first tool string whereby the downhole plug seals against the first tubular string, wherein the setting tool switch is isolated from fluid pressure external of the setting tool. In certain embodiments, the first tool string comprise a sub configured to couple with the first perforating gun, wherein the sub comprises a sub housing comprising first end, a second end opposite the first end, and a central passage that includes a gun switch receptacle, the gun switch which is positioned in the gun switch receptacle, wherein the gun switch establishes an electrical connection with a signal conductor of the first perforating gun and is isolated from fluid pressure external of the gun switch receptacle. In certain embodiments, the first perforating gun comprises a pressure barrier positioned in the central passage of the sub housing and which isolates the gun switch from fluid pressure external of the gun switch receptacle. In some embodiments, the central passage of the sub housing comprises a first bulkhead receptacle extending into the sub housing from the first end, and a second bulkhead receptacle extending into the sub housing from the second end, wherein the gun switch receptacle is positioned between the first bulkhead receptacle and the second bulkhead receptacle, and the pressure barrier comprises a first bulkhead connector positioned in the first bulkhead receptacle, and a second bulkhead connector positioned in the second bulkhead receptacle. In some embodiments, the method comprises (f) rotatably coupling the sub housing with a housing of the first perforating gun to establish an electrical connection between a signal conductor of the first perforating gun and the gun switch.
An embodiment of a method for perforating tubular strings positioned in wellbores comprises (a) lowering a first tool string into a first wellbore, the first tool string comprising a first perforating gun comprising a signal conductor, a sub configured to couple with the first perforating gun, wherein the sub comprises a sub housing comprising first end, a second end opposite the first end, and a central passage that includes a gun switch receptacle, and a gun switch positioned in the gun switch receptacle, wherein the gun switch is isolated from fluid pressure external of the gun switch receptacle, and (b) detonating the first perforating gun in response to transmitting a first gun firing signal from a control system to the gun switch. In some embodiments, the first perforating gun comprises a pressure barrier positioned in the central passage of the sub housing and which isolates the gun switch from fluid pressure external of the gun switch receptacle. In some embodiments, the central passage of the sub housing comprises a first bulkhead receptacle extending into the sub housing from the first end, and a second bulkhead receptacle extending into the sub housing from the second end, wherein the gun switch receptacle is positioned between the first bulkhead receptacle and the second bulkhead receptacle, and the pressure barrier comprises a first bulkhead connector positioned in the first bulkhead receptacle, and a second bulkhead connector positioned in the second bulkhead receptacle. In certain embodiments, the method comprises (d) rotatably coupling the sub housing with a housing of the first perforating gun to establish an electrical connection between a signal conductor of the first perforating gun and the gun switch. In certain embodiments, the method comprises (d) retrieving the first tool string from the first wellbore following (c), (e) lowering a second tool string comprising the gun switch used in the first tool string and a second perforating gun into at least one of the first wellbore and a second wellbore that is different from the first wellbore following (d), and (f) detonating the second perforating gun in response to transmitting a second gun firing signal from the control system to the gun switch. In some embodiments, the method comprises (d) with the first tool string lowered into the first wellbore, transmitting an enabling signal from the control system to a safety switch positioned in a switch receptacle of a safety sub of the first tool string to close the safety switch and thereby permit signal communication between the control system and the gun switch, wherein the safety switch is isolated from fluid pressure external of the safety sub. In some embodiments, the method comprises (d) with the first tool string lowered into the first wellbore, transmitting a setting tool firing signal from the control system to a setting tool switch positioned in a switch receptacle of a setting tool of the first tool string to set a downhole plug of the first tool string whereby the downhole plug seals against the first tubular string, wherein the setting tool switch is isolated from fluid pressure external of the setting tool.
An embodiment of a tool string for perforating a tubular string positioned in a wellbore comprises a perforating gun configured to selectably form perforations in the tubular string, a sub configured to couple with the perforating gun, wherein the sub comprises a sub housing comprising first end, a second end opposite the first end, and a central passage that includes a switch receptacle, a gun switch positionable in the switch receptacle, wherein the gun switch is configured to detonate the perforating gun in response to receiving a gun firing signal from a control system, and wherein the gun switch is isolated from fluid pressure external of the switch receptacle when the gun switch is positioned in the switch receptacle. In some embodiments, the perforating gun comprises a pressure barrier positioned in the central passage of the sub housing and which isolates the gun switch from fluid pressure external of the gun switch receptacle. In some embodiments, the central passage of the sub housing comprises a first bulkhead receptacle extending into the sub housing from the first end, and a second bulkhead receptacle extending into the sub housing from the second end, wherein the gun switch receptacle is positioned between the first bulkhead receptacle and the second bulkhead receptacle, and the pressure barrier comprises a first bulkhead connector positioned in the first bulkhead receptacle, and a second bulkhead connector positioned in the second bulkhead receptacle. In certain embodiments, the tool string comprises a safety sub that comprises a safety switch positionable in a switch receptacle of the safety sub, and wherein the safety switch is isolated from fluid pressure external of the safety sub when it is positioned in the switch receptacle of the safety sub, wherein the safety switch is configured to permit signal communication between the control system and the gun switch in response to the safety switch receiving an enabling signal from the control system. In certain embodiments, the tool string comprises a setting tool that comprises a setting tool switch positionable in a switch receptacle of the setting tool, and wherein the setting tool switch is isolated from fluid pressure external of the setting tool when it is positioned in the switch receptacle of the setting tool, wherein the setting tool switch is configured to set a downhole plug of the tool string whereby the downhole plug seals against the tubular string in response to the setting tool switch receiving a setting tool firing signal from the control system. In some embodiments, the sub is configured to establish an electrical connection between a signal conductor of the perforating gun and the gun switch in response to rotatably coupling the sub housing with a housing of the perforating gun.
For a detailed description of exemplary embodiments of the disclosure, reference will now be made to the accompanying drawings in which:
The following discussion is directed to various exemplary embodiments. However, one skilled in the art will understand that the examples disclosed herein have broad application, and that the discussion of any embodiment is meant only to be exemplary of that embodiment, and not intended to suggest that the scope of the disclosure, including the claims, is limited to that embodiment.
Certain terms are used throughout the following description and claims to refer to particular features or components. As one skilled in the art will appreciate, different persons may refer to the same feature or component by different names. This document does not intend to distinguish between components or features that differ in name but not function. The drawing figures are not necessarily to scale. Certain features and components herein may be shown exaggerated in scale or in somewhat schematic form and some details of conventional elements may not be shown in interest of clarity and conciseness.
In the following discussion and in the claims, the terms “including” and “comprising” are used in an open-ended fashion, and thus should be interpreted to mean “including, but not limited to . . . . ” Also, the term “couple” or “couples” is intended to mean either an indirect or direct connection. Thus, if a first device couples to a second device, that connection may be through a direct connection, or through an indirect connection via other devices, components, and connections. In addition, as used herein, the terms “axial” and “axially” generally mean along or parallel to a central axis (e.g., central axis of a body or a port), while the terms “radial” and “radially” generally mean perpendicular to the central axis. For instance, an axial distance refers to a distance measured along or parallel to the central axis, and a radial distance means a distance measured perpendicular to the central axis. Any reference to up or down in the description and the claims is made for purposes of clarity, with “up”, “upper”, “upwardly”, “uphole”, or “upstream” meaning toward the surface of the borehole and with “down”, “lower”, “downwardly”, “downhole”, or “downstream” meaning toward the terminal end of the borehole, regardless of the borehole orientation.
Referring now to
In some embodiments, system 10 may further include suitable surface equipment for drilling, completing, and/or operating completion system 10 and may include, for example, derricks, structures, reels, pumps, electrical/mechanical well control components, etc. Tool string 20 is generally configured to perforate casing string 12 to provide for fluid communication between formation 6 and wellbore 4 at predetermined locations to allow for the subsequent hydraulic fracturing of formation 6 at the predetermined locations.
In this embodiment, tool string 20 has a central or longitudinal axis 25 and generally includes a cable head 24, a casing collar locator (CCL) 26, a direct connect sub 500, a plurality of perforating guns 300A, 300B, a switch sub 100, a plug-shoot firing head 600, a setting tool 30, and a downhole or frac plug 34. Cable head 24 is the uppermost component of tool string 20 and includes an electrical connector for providing electrical signal and power communication between the wireline 22 and the other components (CCL 26, perforating guns 300A, 300B, setting tool 30, etc.) of tool string 20. CCL 26 is coupled to a lower end of the cable head 24 and is generally configured to transmit an electrical signal to the surface via wireline 22 when CCL 26 passes through a casing collar, where the transmitted signal may be recorded at the surface as a collar kick to determine the position of tool string 20 within wellbore 4 by correlating the recorded collar kick with an open hole log. The direct connect sub 500 (shown schematically in
Perforating guns 300A, 300B (shown schematically in
In this embodiment, switch sub 100 (shown schematically in
In this embodiment, tool string 20 further includes setting tool 30 and downhole plug 34, where setting tool 30 is coupled to a lower end of plug-shoot firing head 600 and is generally configured to set or install downhole plug 34 within casing string 12 to isolate desired segments of the wellbore 4, as will be discussed further herein. Once downhole plug 34 has been set by setting tool 30, an outer surface of downhole plug 34 seals against an inner surface of casing string 12 to restrict fluid communication through wellbore 4 across downhole plug 34. Downhole plug 34 of tool string 20 may be any suitable downhole or frac plug known in the art while still complying with the principles disclosed herein. Although in this embodiment tool string 20 generally includes cable head 24, CCL 26, direct connect sub 500, perforating guns 300A, 300B, switch sub 100, plug-shoot firing head 600, setting tool 30, and downhole or frac plug 34, in other embodiments, the configuration of tool string 20 may vary. For instance, in some embodiments, tool string 20 may comprise weight bars and/or a fish neck at an upper or uphole end thereof. In certain embodiments, tool string 20 may comprise a release tool for releasing at least a portion of tool string 20 in the event that tool string 20 becomes stuck in wellbore 4. In some embodiments, tool string 20 may also comprise a safety sub.
Referring to
In this embodiment, switch sub 100 generally includes an outer housing 102, an electronic first or gun switch 120, a multi-contact bulkhead connector 160, and a second or single-contact bulkhead connector 220. Housing 102 of switch sub 100 has a first or upper end 104, a second or lower end 106, a central bore or passage defined by a generally cylindrical inner surface 108 extending between ends 104, 106, and a generally cylindrical outer surface 110 extending between ends 104, 106. The central passage of housing 102 includes a switch receptacle 112, an upper bulkhead receptacle 114 extending between upper end 104 and switch receptacle 112, and a lower bulkhead receptacle 116 extending between switch receptacle 112 and the lower end 106 of housing 102. An annular first or upper shoulder 113 of the inner surface 108 separates upper bulkhead receptacle 114 and switch receptacle 112 while an annular second or lower shoulder 115 of inner surface 108 separates lower bulkhead receptacle 116 from switch receptacle 112. Gun switch 120 is disposed in switch receptacle 112, multi-contact bulkhead connector 160 is disposed in upper bulkhead receptacle 114, and single-contact bulkhead connector 220 is disposed in lower bulkhead receptacle 116. In this embodiment, the outer surface 110 includes a pair of annular first or upper seal assemblies 117A positioned thereon, a pair of annular second or lower seal assemblies 117B positioned thereon, and a pair of releasable or threaded connectors 118 formed thereon and positioned at the ends 104, 106 of housing 102.
Referring to
In this embodiment, the electrical circuit 124 positioned on the PCB 122 of gun switch 120 includes a first or upper electrical connector 130, a second or lower electrical connector 140, and a pair of circumferentially spaced radial ground contacts 150. As shown particularly in
The detonator contacts 134 of upper electrical connector 130 allow for electrical signals to be selectably communicated between wireline 22 and a detonator of upper perforating gun 300A, as will be described further herein. Ground contacts 150 extend radially outwards from the outer surface 128 of potting compound 126 and are configured to contact inner surface 108 of the switch receptacle 112 of housing 102 to thereby ground the electrical circuit 124 of gun switch 120 to housing 102. In some embodiments, each ground contact 150 comprises a biasing member configured to bias ground contacts 150 into engagement with the inner surface 108 of housing 102, thereby maintaining contact between ground contacts 150 and housing 102 during operation of tool string 20.
Referring to
Additionally, multi-contact bulkhead connector 160 is configured to act as a pressure bulkhead isolating switch 120 from pressure in upper perforating gun 300A (due to the firing of gun 300A, for example) and/or pressure in the environment surrounding switch sub 100. In other words, multi-contact bulkhead connector 160 is configured to restrict the communication of fluid pressure between upper end 164 and lower end 166. The outer surface 168 of multi-contact bulkhead connector 160 comprises an annular engagement surface 171 extending from upper end 164 and a pair of opposing flanking engagement surface 173 extending from annular engagement surface 171. In this embodiment, annular engagement surface 171 comprises a planar surface extending between opposing ends of an arcuate surface of annular engagement surface 171. Additionally, in this embodiment, flanking engagement surfaces 173 are circumferentially spaced approximately 180 degrees about a longitudinal axis of multi-contact bulkhead connector 160.
The PCB of multi-contact bulkhead connector 160 includes an electrical circuit that comprises electronic components including a first or upper electrical connector 172, a second or lower electrical connector 180 in signal communication with upper electrical connector 172, and a pair of circumferentially spaced radial circuits or contacts 190 in signal communication with lower electrical connector 180. Connectors 172, 180 each extend along central axis 165 while radial contacts 190 are spaced from central axis 165 and extend radially outwards therefrom. In this embodiment, upper electrical connector 172 comprises a pair of detonator circuits or female contacts. Lower electrical connector 180 comprises a wireline circuit or male contact 182 and a pair of detonator circuits or male contacts 184. Radial contacts 190 are electrically connected to the wireline contact 182 of lower electrical connector 180, thereby permitting signals and/or data to be transmitted from wireline 22 to the electrical circuit 124 of switch sub 100 via the insertion of the wireline contact 182 of lower electrical connector 180 into the wireline contact 132 of the upper electrical connector 130 of switch 120.
In this embodiment, the PCB of multi-contact bulkhead connector 160 does not include transistors, resistors, or other electronic components beyond electrical connectors 172, 180, 190, and the electrical conductors extending therebetween; however, in other embodiments, the PCB of multi-contact bulkhead connector 160 may include additional electronic components. Additionally, in this embodiment, housing 162 is overmolded to the previously formed PCB to form multi-contact bulkhead connector 160, where housing 162 comprises one of Polyether ether ketone (PEEK), Ultem, or a similar material; however, in other embodiments, the material from which housing 162 is comprised may vary. In some embodiments, housing 162 may comprise one or more strengthening materials, such as glass.
Additionally, the detonator contacts of upper electrical connector 172 are electrically connected to detonator contacts 184 of lower electrical connector 180. In this configuration, electrical signals may be selectably communicated between the detonator of upper perforating gun 300A and electrical circuit 124 of switch 120 via the insertion of the detonator contacts 184 of lower electrical connector 180 into the detonator contacts 134 of the upper electrical connector 130 of switch 120. In this embodiment, switch sub 100 includes an annular first or upper retainer 200 (shown in
As shown particularly in
Additionally, single-contact bulkhead connector 220 is configured to act as a pressure bulkhead isolating switch 120 from pressure in lower perforating gun 300B (due to the firing of gun 300B, for example) and/or pressure in the environment surrounding switch sub 100. In this embodiment, switch sub 100 includes an annular second or lower retainer 240 having an outer surface that includes a releasable or threaded connector 242 which releasably or threadably connects to a corresponding threaded connector formed on the inner surface 108 of lower bulkhead receptacle 116 to couple lower retainer 240 to housing 102. Additionally, an inner surface of lower retainer 240 includes an annular shoulder that matingly engages an annular shoulder formed on the outer surface of the insulation sleeve 230 of single-contact bulkhead connector 220 to thereby retain lower bulkhead 220 within lower bulkhead receptacle 116 and limit relative axial movement between single-contact bulkhead connector 220 and housing 102. In this embodiment, force applied to single-contact bulkhead connector 220 due to pressure applied to a lower end of bulkhead connector 220 is transferred to housing 102 via contact between an upper end of bulkhead connector 220 and the lower shoulder 115 of housing 102, thereby restricting pressure applied to the lower end of bulkhead connector 220 from being communicated to switch 120.
Referring again to
The charge tube 320 of each perforating gun 300A, 300B is generally cylindrical and has a first or upper end 322, a second or lower end 324, and a central bore or passage 326 extending between ends 322, 324. As will be described further herein, charge tube 320 is configured to receive a plurality of explosive shaped charges (not shown in
In this embodiment, upper endplate 330 of each perforating gun 300A, 300B includes a central bore or passage 332 that receives a first or upper electrical connector 340 that includes a generally cylindrical electrical conductor 342 and a biasing member 344 that biases electrical conductor 342 towards the single-contact bulkhead connector 220 of switch sub 100. Particularly, biasing member 344 acts against an annular shoulder of electrical conductor 342 to maintain contact between an upper end of electrical conductor 342 and a lower end 226 of the electrical conductor 222 of single-contact bulkhead connector 220, thereby providing an electrical connection between the upper electrical connector 340 of lower perforating gun 300B and the single-contact bulkhead connector 220 of switch sub 200. Additionally, a lower end of electrical conductor 342 is connected to a signal conductor or charge tube cable 346 that extends between an upper end and a lower end of the charge tube 320 of lower perforating gun 300B. In this configuration, signals and/or data may be selectably communicated from wireline 22 to charge tube cable 346 (and components of tool string 20 positioned downhole of lower perforating gun 300B) via the electrical connection formed between single-contact bulkhead connector 220 of switch sub 100 and the upper electrical connector 340 of lower perforating gun 300B.
In this embodiment, lower endplate 334 of each perforating gun 300A, 300B includes a central bore or passage that receives a second or lower electrical connector 350. Referring to
In this embodiment, the outer surface 360 of housing 352 includes a plurality of circumferentially spaced flexible or snap connectors 362 positioned proximal to the lower end 356 of housing 352. Snap connectors 362 are configured to connect housing 352 to an inner surface of the lower endplate 334 of charge tube 320. At least a portion of the central passage 358 of housing 352 forms a detonator receptacle 364 extending from the upper end 354 of housing 352, wherein detonator receptacle 364 extends along central axis 355. As will be described further herein, detonator receptacle 364 is configured to receive one of the detonator assemblies 400A, 400B and permit relative rotation between lower electrical connector 350 and detonator assembly 400A, 400B when detonator assembly 400A, 400B is received in detonator receptacle 364.
Additionally, housing 352 includes a detonator cord or “detcord” receptacle 366 that also extends into the lower end 366 of housing 352 in a direction parallel with, but radially offset from, central axis 355. Detcord receptacle 366 is configured to receive an end of a detonator cord or detcord connected to the shaped charges of charge tube 320. Additionally, detcord receptacle 366, being positioned adjacent detonator receptacle 364, is configured to position the end of the detcord adjacent one of the detonator assemblies 400A, 400B such that the detonator assembly 400A, 400B may selectably initiate or ignite the detcord and thereby fire the shaped charges coupled to charge tube 320. Housing 352 further includes an electrical stab connector 368 positioned adjacent upper end 354. Stab connector 368 includes a receptacle 370 extending into housing 352 in a direction parallel with, but radially offset from, central axis 355. Stab connector 368 additionally includes a protrusion 372 formed on outer surface 360 of housing 352.
As shown particularly in
Referring to
The connector housing 420 of detonator assembly 400 has a first end 422, a second end 424 opposite first end 422, and a central bore or passage defined by a generally cylindrical inner surface 426 extending between second end 424 and a base 425. Additionally, connector housing 420 comprises separate, connectable components to assist with assembling connector housing 420 with detonator 402. In this embodiment, connector housing 420 comprises a first arcuate portion 421 and a second arcuate portion 423. A flexible snap connector 428 formed along an edge of second arcuate portion 423 may be matingly inserted into a corresponding groove formed in first arcuate portion 421 to couple arcuate portions 421, 423 together. When arcuate portions 421, 423 of connector housing 420 are in an assembled configuration, inner surface 426 of connector housing 420 forms an annular groove 430 in which the annular shoulder 405 of detonator housing 404 may be received to restrict relative axial movement between connector housing 420 and detonator 402 when detonator assembly 400 is in an assembled configuration.
In this embodiment, connector housing 420 includes a pair of apertures 432 that extend through base 425 and are configured to allow for the passage of terminals 410 of detonator 402 therethrough. Terminals 410 of detonator assembly 400 may be inserted into the female contacts of the upper electrical connector 172 of multi-contact bulkhead connector 160 to provide an electrical connection therebetween. In this manner, an activation or firing signal may be selectably transmitted from the electrical circuit 124 of switch 120 to the detonator 402 of detonator assembly 400.
In this embodiment, connector housing 420 includes a flexible or snap connector 434 extending from base 425 and configured to matingly engage the engagement surfaces 171, 173 of multi-contact bulkhead connector 160. Particularly, snap connector 434 includes a pair of circumferentially spaced arms 436 configured to matingly engage the flanking engagement surfaces 173 of multi-contact bulkhead connector 160. Arms 436 permit snap connector 434 to latch to multi-contact bulkhead connector 160, inhibiting or preventing disconnection of snap connector 434 from bulkhead connector 160 while also restricting relative rotation between connector housing 420 and bulkhead connector 160.
Mating engagement between arms 436 of connector housing 420 with flanking engagement surfaces 173 of multi-contact bulkhead connector 160 assists with angularly aligning detonator assembly 400 with multi-contact bulkhead connector 160 such that terminals 410 of detonator assembly 400 may be axially inserted into the corresponding female contacts of the upper electrical connector 172 of multi-contact bulkhead connector 160, thereby providing an electrical connection between detonator 402 and the electrical circuit 124 of switch 120 via multi-contact bulkhead connector 160. In some embodiments, a compliant material (e.g., rubber) may be positioned and compressed at the interface between snap connector 434 and multi-contact bulkhead connector 160 to dampen or prevent vibration and to further inhibit disconnection of the snap connector 434 from the multi-contact bulkhead connector 160. Additionally, as described above, detonator assembly 400 fits within the detonator receptacle 364 of lower electrical connector 350. Moreover, detonator assembly 400 is configured to permit relative rotation between lower electrical connector 350 and multi-contact bulkhead connector 160 when detonator 402 is electrically connected to the upper electrical connector 172 of multi-contact bulkhead connector 160.
In this embodiment, prior to installation of detonator assembly 20 within one of the components of tool string 20, detonator assembly 400 includes a shunt cap 440 configured to prevent the accidental initiation of detonator 402. Particularly, when detonator assembly 400 is in the assembled configuration (shown in
Integrated shunt 464 is affixed or coupled to a first of the terminals 410A of detonator assembly 460 and is biased into contact with a second of the terminals 410B to provide a direct electrical connection between terminals 410A, 410B. Unlike the shunt cap 440 of detonator assembly 400, integrated shunt 464 does not need to be mechanically removed from detonator assembly 460 prior to the assembly of tool string 20. Instead, as terminals 410A, 410B of detonator 402 are inserted into the female contacts of the upper electrical connector 172 of multi-contact bulkhead connector 160, the upper electrical connector 172 contacts integrated shunt 464 and bends or flexes shunt 464 out of contact with the second terminal 410B, thereby removing the electrical short formed between terminals 410A, 410B. Direct electrical contact or an electrical short may be reestablished between terminals 410A, 410B by uncoupling detonator assembly 460 from multi-contact bulkhead connector 160, thereby permitting integrated shunt 464 to flex into contact with second terminal 410B. Thus, integrated shunt 464 may be biased into contact with second terminal 410B. Thus, integrated shunt 464 may prevent inadvertent initiation of detonator 402 while reducing the time required for assembling tool string 20 by eliminating the need to insert and remove a mechanical shunt from detonator assembly 460 prior to coupling detonator assembly 460 with multi-contact bulkhead connector 160.
Referring again to
In this embodiment, the central passage of housing 502 includes a switch receptacle 514, an upper bulkhead receptacle 515 extending between upper end 504 and switch receptacle 514, and a lower bulkhead receptacle 516 extending between switch receptacle 514 and the lower end 506 of housing 502. An annular first or upper shoulder 517 of the inner surface 508 of housing 502 separates upper bulkhead receptacle 515 and switch receptacle 514 while an annular second or lower shoulder 519 of inner surface 508 separates lower bulkhead receptacle 516 from switch receptacle 514. Safety switch 520 is disposed in switch receptacle 514, biased bulkhead connector 560 is disposed in upper bulkhead receptacle 515, and single-contact bulkhead connector 220 is disposed in lower bulkhead receptacle 516. Although in this embodiment safety switch 520 is housed within direct connect sub 500, in other embodiments, safety switch 520 may be located in a component of tool string 20 other than direct connect sub 500. For example, in an embodiment where tool string 20 comprises a release tool configured to release at least a portion of tool string 20, safety switch 520 may be positioned in a safety sub located between CCL 26 and the release tool, the release tool being positioned between the safety sub and direct connect sub 500.
Referring to
Safety switch 520 has a longitudinal or central axis 525, an axial maximum length 520L (extending along central axis 525), and a maximum diameter 520D (extending orthogonal central axis 525). In the embodiment of
By providing safety switch 520 with an exterior shape which differs from an exterior shape of gun switch 120, safety switch 520 may be easier to visually distinguish from gun switch 120 in the field by operators or personnel of completion system 10, thereby reducing the likelihood of a safety switch 520 being mistakenly installed in a switch sub 100 and/or a gun switch 120 being mistakenly installed in a direct connect sub 500 by personnel of completion system 10. In some embodiments, the maximum length 520L and/or maximum diameter 520D of safety switch 520 differs from the maximum length 120L and/or maximum diameter 120D of gun switch 120 to further distinguish safety switch 520 from gun switch 120. Potting compound 526 comprises a solid or gelatinous material configured to provide electrical insulation and resistance to shock and/or vibration at elevated temperatures (e.g., 300-350 degrees Fahrenheit or greater) to thereby protect electrical circuit 524. In some embodiments, potting compound 526 comprises an epoxy resin; however, in other embodiments, the material from which potting compound 526 is comprised may vary. Additionally, the potting compound 526 of safety switch 520 may comprise a material which differs from the material comprising the potting compound 126 of gun switch 120.
In this embodiment, the electrical circuit 524 positioned on the PCB 522 of safety switch 520 includes a first or upper electrical connector 535, a second or lower electrical connector 540, and a pair of circumferentially spaced ground contacts 550. Electrical connectors 535, 540 each extend along central axis 525 while ground contacts 550 are offset from central axis 525 and extend radially outwards therefrom. As shown particularly in
In this embodiment, the ground contacts 550 of electrical circuit 524 extend radially outwards from the outer surface 528 of potting compound 526 and are configured to contact inner surface 508 of the switch receptacle 514 of housing 502 to thereby ground the electrical circuit 524 of safety switch 520 to housing 502. In some embodiments, each ground contact 550 comprises a biasing member configured to bias ground contacts 550 into engagement with the inner surface 508 of housing 502, thereby maintaining contact between ground contacts 550 and the housing 502 of direct connect sub 500.
As shown particularly in
The lower electrical conductor 576 of biased bulkhead connector 560 includes a first or upper male contact 578, and a second or lower male contact 580. Upper male contact 578 of lower electrical conductor 576 is coupled to biasing member 572, forming an electrical connection between upper electrical conductor 574 and lower electrical conductor 576. Additionally, the lower end 580 of lower electrical conductor 576 is insertable into the female contact 536 of the upper electrical connector 535 of safety switch 520, thereby providing an electrical connection between lower electrical conductor 576 and the electrical circuit 524 of safety switch 520.
An annular insulation sleeve 582 surrounds lower electrical conductor 576 to prevent direct electrical contact from forming between lower electrical conductor 576 and the inner surface of housing 562. Additionally, a pair of annular seal assemblies 584 surround insulation sleeve 582 and sealingly engage the inner surface of housing 562. In this configuration, seal assemblies 578 disposed about housing 562 and seal assemblies 584 disposed about insulation sleeve 582 restrict fluid communication between the upper bulkhead receptacle 515 and the switch receptacle 514 of housing 502. In this embodiment, biasing member 572 acts against upper electrical conductor 574 to bias conductor 574 in a first or upwards axial direction. Additionally, biasing member 572 acts against lower electrical conductor 576 to bias conductor 576 in a second or lower axial direction, opposite the upper axial direction. In this manner, biasing member 572 biases upper electrical conductor 574 into electrical contact with a corresponding electrical connector of CCL 26 (not shown in
As described above, a single-contact bulkhead connector 220, similar in configuration as the bulkhead connector 220 of switch sub 100, is positioned in the lower bulkhead receptacle 516 of housing 502. The upper male contact 224 of the electrical conductor 222 of single-contact bulkhead connector 220 is insertable into the female contact 542 of the lower electrical connector 540 of safety switch 520, thereby providing an electrical connection between electrical conductor 222 of single-contact bulkhead connector 220 and the electrical circuit 524 of safety switch 520. Additionally, the lower male contact 226 of electrical conductor 222 is configured to contact the electrical conductor 342 of the upper endplate 330 of upper perforating gun 300A to form an electrical connection between the electrical conductor 222 of single-contact bulkhead connector 220 and the charge tube cable 346 of upper perforating gun 300A. An annular second or lower retainer 592 releasably or threadably couples to the inner surface 508 of housing 502 at the lower end 506 thereof. Lower retainer 592 retains or locks single-contact bulkhead connector 220 within the lower bulkhead receptacle 516 of housing 502. In this embodiment, force applied to single-contact bulkhead connector 220 due to pressure applied to a lower end of bulkhead connector 220 is transferred to housing 502 via contact between an upper end of bulkhead connector 220 and the lower shoulder 519 of housing 502, thereby restricting pressure applied to the lower end of bulkhead connector 220 from being communicated to safety switch 520.
Referring again to
In this embodiment, the central passage of housing 602 includes a switch receptacle 614, an upper bulkhead receptacle 615 extending between upper end 604 and switch receptacle 614, and an igniter receptacle 616 extending between switch receptacle 614 and the lower end 606 of housing 602. An annular first or upper shoulder 617 of the inner surface 608 of housing 602 separates upper bulkhead receptacle 615 and switch receptacle 614 while an annular second or lower shoulder 619 of inner surface 608 separates igniter receptacle 616 from switch receptacle 614. Combination switch 620 is disposed in switch receptacle 614, multi-contact bulkhead connector 160 is disposed in upper bulkhead receptacle 515, and an igniter assembly 700 of the setting tool 30 (not shown in
As shown particularly in
Combination switch 620 has an exterior shape that differs from the exterior shapes of switches 120, 520. For example, the maximum length 620L and/or maximum diameter 620D of combination switch 620 may differ from the maximum lengths 120L, 520L and/or maximum diameters 120D, 520 of switches 120, 520, respectively. In other embodiments, the exterior shape of combination switch 620 may differ from the exterior shapes of switches 120, 520 in other ways (e.g., a different cross-sectional shape, the inclusion of surface features, etc.). By providing combination switch 620 with a different exterior shape than the exterior shapes of switches 120, 520, combination switch 620 is easier to distinguish from switches 120, 520 in the field by personnel of completion system 10.
In this embodiment, the electrical circuit 624 positioned on the PCB 622 of combination switch 620 includes a first or upper electrical connector 630, a second or lower electrical connector 640, and a pair of circumferentially spaced ground contacts 650. As shown particularly in
The detonator contacts 634 of upper electrical connector 630 allow for electrical signals to be selectably communicated between wireline 22 and a detonator of lower perforating gun 300B, as will be described further herein. Ground contacts 650 extend radially outwards from the outer surface 628 of potting compound 626 and are configured to contact inner surface 608 of the switch receptacle 614 of housing 602 to thereby ground the electrical circuit 624 of combination switch 620 to housing 602. In some embodiments, each ground contact 650 comprises a biasing member configured to bias ground contacts 650 into engagement with inner surface 608, thereby maintaining contact between ground contacts 650 and housing 602.
As shown particularly in
In this embodiment, force applied to the multi-contact bulkhead connector 160 of plug-shoot firing head 600 due to pressure applied to the upper end 164 of upper bulkhead connector 160 is transferred to housing 602 via contact between the lower end 166 of bulkhead connector 160 and the upper shoulder 617 of housing 602, thereby restricting pressure applied to upper end 164 of upper bulkhead connector 160 from being communicated to combination switch 620. Additionally, force applied to igniter assembly 700 due to pressure applied to a lower end thereof is transferred to housing 602 via contact between an upper end of igniter assembly 700 and the lower shoulder 619 of housing 602, thereby restricting pressure applied to the lower end of igniter assembly 700 from being communicated to combination switch 620.
Having described structural features of tool string 20, an embodiment of a method for assembling and operating tool string 20 will now be described. As will be described further herein, at least some components of tool string 20 may be assembled by the manufacturer, or the end user or operator of tool string 20 prior to transporting tool string 20 to a well site (e.g., the location of wellbore 4) of completion system 10. The remaining components of tool string 20 may be assembled at the wellsite of completion system 10 but prior to the insertion of tool string 20 into wellbore 4.
In this embodiment, detonator assemblies 400A, 400B of tool string 20 are assembled by the manufacturer, with required safeguards in place, prior to transportation of tool string 20 to the wellsite of completion system 10. Referring to
As shown in
Prior to assembling perforating guns 300A, 300B with the other components of tool string 20, as will be discussed further herein, the charge tube 320 of each perforating gun 300B is assembled and installed within its corresponding housing 302.
Particularly, in this embodiment, with charge tube 320 disposed external of its respective housing 302, endplates 330, 334 are attached by a user of perforating guns 300A, 300B and/or tool string 20 (e.g., a manufacturer, end user, etc., of tool string 20 or components thereof) to the ends 322, 324, respectively of charge tube 320 to thereby assemble charge tube 320. Lower electrical connector 350 is attached to lower endplate 334 prior to coupling lower endplate 334 to the lower end 324 of charge tube 320. In some embodiments, charge tube cable 346, which extends through charge tube 320, is electrically connected to the elongate contact of lower electrical connector 350 prior following the coupling lower endplate 334 to the lower end 324 of charge tube 320; however, in other embodiments, charge tube cable 346 is connected to lower electrical connector 350 prior to the coupling of lower endplate 334 to charge tube 320.
In this embodiment, following the assembly of endplates 330, 334, lower electrical connector 350, and charge tube cable 346, the user positions a plurality of explosive shaped charges in the openings formed in charge tube 320, and ballistically couples the detcord to each of the shaped charges coupled to charge tube 320. With the plurality of explosive shaped charged positioned in the openings of the charge tube 320, the user may insert an end of the detcord into the detcord receptacle 366 of lower electrical connector 350. An interference fit is formed between the end of the detcord and an inner surface of the detcord receptacle 366, and thus, friction between the end of the detcord and the inner surface of the detcord receptacle 366 prevents, or at least inhibits, removal of the end of the detcord from detcord receptacle 366. With the end of the detcord inserted into detcord receptacle 366, charge tube 320 may be loaded into its respective housing 302 by the user of perforating guns 300A, 300B, and/or tool string 20.
Referring again to
In some embodiments, the lower electrical connector 540 of safety switch 520 is electrically connected to the single-contact bulkhead connector 220 of direct connect sub 500, which is received in lower bulkhead receptacle 516 of housing 502, when safety switch 520 is inserted into the switch receptacle 514 of housing 502; however, in other embodiments, single-contact bulkhead connector 220 may be inserted into lower-bulkhead receptacle 516 and connected to safety switch 520 following the insertion of safety switch 520 into switch receptacle 514. Following the insertion of biased bulkhead connector 560 and single-contact bulkhead connector 220 into housing 502, retainers 590, 592 are coupled to the inner surface 508 of housing 502 to lock safety switch 520 and bulkhead connectors 560, 220 in the central passage of housing 502, and thereby complete the assembly of direct connect sub 500.
Following the assembly of direct connect sub 500, the lower end 506 of the housing 502 of direct connect sub 500 is inserted into the upper end 304 of the housing 302 of upper perforating gun 300A. As housing 502 of direct connect sub 500 is inserted into the housing 302 of upper perforating gun 300A, housing 502 is rotated relative to housing 302 to threadably connect a threaded connector 513 of housing 502 with a corresponding threaded connector positioned at the upper end 304 of housing 302. Additionally, as the housing 502 of direct connect sub 500 is inserted into the housing 302 of upper perforating gun 300A, lower male contact 226 of the single-contact bulkhead connector 220 of direct connect sub 500 contacts electrical conductor 342 of the upper electrical connector 340 of upper perforating gun 300A, thereby forming an electrical connection between safety switch 520 and the charge tube cable 346 of upper perforating gun 300A.
Referring to
In some embodiments, the lower electrical connector 140 of gun switch 120 is electrically connected to single-contact bulkhead connector 220, which is received in lower bulkhead receptacle 116 of housing 102, when gun switch 120 is inserted into the switch receptacle 112 of housing 102; however, in other embodiments, single-contact bulkhead connector 220 may be inserted into lower-bulkhead receptacle 116 and connected to gun switch 120 following the insertion of gun switch 120 into switch receptacle 112. Following the insertion of multi-contact bulkhead connector 160 and single-contact bulkhead connector 220 into housing 102, retainers 200, 240 are coupled to the inner surface 108 of housing 102 to lock gun switch 120 and bulkhead connectors 160, 220 in the central passage of housing 102, and complete the assembly of switch sub 100.
In this embodiment, following the assembly of switch sub 100, upper detonator assembly 400A is connected to the multi-contact bulkhead connector 160 of switch sub 100. Particularly, arms 436 of the snap connector 434 of upper detonator assembly 400A are circumferentially aligned with the flanking engagement surfaces 173 of multi-contact bulkhead connector 160 and the engagement surfaces 171, 173 of connector 160 are inserted into and latched onto snap connector 434. With upper detonator assembly 400A connected to multi-contact bulkhead connector 160 of switch sub 100, switch sub 100 may be connected to the upper perforating gun 300A.
Particularly, in this embodiment, upper end 104 of the housing 102 of switch sub 100 is inserted into the lower end 306 of the housing 302 of upper perforating gun 300A. As housing 102 of switch sub 100 is inserted into the housing 302 of upper perforating gun 300A, housing 102 is rotated relative to housing 302 to threadably connect a threaded connector 118 of housing 102 with a corresponding threaded connector positioned at the lower end 306 of housing 302. Additionally, as housing 102 of switch sub 100 is inserted into the housing 302 of upper perforating gun 300A, detonator 402 of upper detonator assembly 400A is axially and slidably inserted into the detonator receptacle 364 of the lower electrical connector 350 (indicated by arrow 455 in
Also following the assembly of switch sub 100, the lower end 106 of the housing 102 of switch sub 100 is inserted into the upper end 304 of the housing 302 of lower perforating gun 300B. As housing 102 of switch sub 100 is inserted into the housing 302 of lower perforating gun 300B, housing 102 is rotated relative to housing 302 to threadably connect a threaded connector 118 of housing 102 with a corresponding threaded connector positioned at the upper end 304 of housing 302. Additionally, as the housing 102 of switch sub 100 is inserted into the housing 302 of lower perforating gun 300B, lower male contact 226 of single-contact bulkhead connector 220 contacts electrical conductor 342 of the upper electrical connector 340 of lower perforating gun 300B, thereby forming an electrical connection between gun switch 120 and the charge tube cable 346 of lower perforating gun 300B.
Referring again to
In some embodiments, the lower electrical connector 640 of combination switch 620 is electrically connected to igniter assembly 700 when combination switch 620 is inserted into the switch receptacle 614 of housing 602; however, in other embodiments, igniter assembly 700 may be connected to combination switch 620 following the insertion of combination switch 620 into switch receptacle 614. With combination switch 620 and multi-contact bulkhead connector 160 received in the central passage of housing 602, housing 602 may be coupled to setting tool 30 of tool string 20. Additionally, retainer 660 is coupled to the inner surface 608 of housing 602 to lock combination switch 620 and multi-contact bulkhead connector 160 in the central passage of housing 602.
With combination switch 620 and multi-contact bulkhead connector 160 received in the central passage of housing 602, lower detonator assembly 400B is connected to multi-contact bulkhead connector 160. Particularly, arms 436 of the snap connector 434 of lower detonator assembly 400B are circumferentially aligned with the flanking engagement surfaces 173 of multi-contact bulkhead connector 160 and the engagement surfaces 171, 173 of connector 160 are inserted into and latched onto snap connector 434, thereby coupling lower detonator assembly 400B with multi-contact bulkhead connector 160.
Following the assembly of lower perforating gun 300B, upper end 604 of the housing 602 of plug-shoot firing head 600 may be inserted into the lower end 306 of the housing 302 of lower perforating gun 300B. As housing 602 of plug-shoot firing head 600 is inserted into the housing 302 of lower perforating gun 300B, housing 602 is rotated relative to housing 302 to threadably connect the threaded connector 613 of housing 602 with a corresponding threaded connector positioned at the lower end 306 of housing 302. Additionally, as housing 602 of plug-shoot firing head 600 is inserted into the housing 302 of lower perforating gun 300B, detonator 402 of lower detonator assembly 400B is axially inserted into the detonator receptacle 364 of the lower electrical connector 350, thereby positioning detonator 402 adjacent the detcord positioned in detcord receptacle 366 of the lower electrical connector 350 of lower perforating gun 300B. In this embodiment, detonator 402 is positioned along the central axis of lower perforating gun 300B while the end of the detcord, received in detcord receptacle 366, is offset from the central axis of lower perforating gun 300B.
As detonator 402 is inserted through detonator receptacle 364 of the lower electrical connector 350, the annular contact 382 of lower electrical connector 350 contacts the radial contacts 190 of the multi-bulkhead connector 160 of plug-shoot firing head 600, thereby providing an electrical connection between the charge tube cable 346 of lower perforating gun 300B and multi-bulkhead connector 160. Lower electrical connector 350 of lower perforating gun 300B permits relative rotation between connector 350 and multi-contact bulkhead connector 160 as plug-shoot firing head 600 is rotatably coupled with lower perforating gun 300B. In some embodiments, the assembly of plug-shoot firing head 600 with setting tool 30 and lower perforating gun 300B, as described above, may be accomplished at the well site of completion system 10 or at a location distal the well site.
In this embodiment, following the assembly of plug-shoot firing head 600 with lower perforating gun 300B and setting tool 30, upper end 504 of the housing 502 of direct connect sub 500 may be releasably or threadably connected to a lower end of the CCL 26 of tool string 20. As direct connect sub 500 is connected to CCL 26, electrical conductor 574 contacts a corresponding conductor of CCL 26 to establish an electrical connection between the biased bulkhead connector 560 of direct connect sub 500 and CCL 26. The electrical connection between CCL 26 and direct connect sub 500 permits the selectable communication of signals and/or data between wireline 22 and components positioned downhole of direct connect sub 500 (e.g., switch sub 100, perforating guns 300A, 300B, plug-shoot firing head 600, etc.).
Referring to
For example, an electrical connection permitting selectable communication of signals and/or data between the safety switch 520 of direct connect sub 500 and the gun switch 120 of switch sub 100 is formed by or in response to rotatably coupling the housing 102 of switch sub 100 to the housing 302 of upper perforating gun 300A and rotatably coupling the housing 302 of upper perforating gun 300A with the housing 502 of switch sub direct connect sub 500. Thus, in order to assemble direct connect sub 500, upper perforating gun 300A, and switch sub 100, the charge tube cable 346 of upper perforating gun 300A does not need to be electrically wired (e.g., by personnel of completion system 10) to either gun switch 120 or safety switch 520. Instead, the electrical connection between charge tube cable 346 with both safety switch 520 of direct connect sub 500 and gun switch 120 of switch sub 100 is made simply by axially inserting both direct connect sub 500 and switch sub 100 into the housing 302 of upper perforating gun 300A.
Similarly, an electrical connection permitting selectable communication of signals and/or data between the gun switch 120 of switch sub 100 and the combination switch 620 of plug-shoot firing head 600 is formed by or in response to rotatably coupling the housing 602 of plug-shoot firing head 600 to the housing 302 of lower perforating gun 300B and rotatably coupling the housing 302 of lower perforating gun 300B with the housing 102 of switch sub 100. Thus, in order to assemble switch sub 100, lower perforating gun 300B, and plug-shoot firing head 600, the charge tube cable 346 of lower perforating gun 300B does not need to be electrically wired (e.g., by personnel of completion system 10) to either gun switch 120 or combination switch 620.
In this embodiment, tool string 20 is configured such that the switches 120, 520, 620 may be reused following the firing of perforating guns 300A, 300B. Particularly, multi-contact bulkhead connector 160 and the single-contact bulkhead connector 220 of switch sub 100 shield gun switch 120 from the pressure (which may exceed 20,000 pounds per square inch (PSI) in some applications) released following the detonation of the shaped charges of perforating guns 300A, 300B by inhibiting or preventing the communication of fluid pressure from perforating guns 300A, 300B to the switch receptacle 112 of housing 102, thereby preventing damage from occurring to gun switch 120 from the activation of perforating guns 300A, 300B. Additionally, biased bulkhead connector 560 and the single-contact bulkhead connector 220 of direct connect sub 500 shield safety switch 520 from the pressure released following the detonation of the shaped charges of perforating guns 300A, 300B by inhibiting or preventing the communication of fluid pressure from perforating guns 300A, 300B to the switch receptacle 514 of housing 502, thereby preventing damage from occurring to safety switch 520 from the activation of perforating guns 300A, 300B. Further, in some embodiments, igniter assembly 700 comprises a pressure bulkhead such that multi-contact bulkhead connector 160 of plug-shoot firing head 600 and the pressure bulkhead of igniter assembly 700 shield combination switch 620 from the pressure released following the detonation of the shaped charges of perforating guns 300A, 300B by inhibiting or preventing the communication of fluid pressure from perforating guns 300A, 300B to the switch receptacle 614 of housing 602, thereby preventing damage from occurring to combination switch 620 from the activation of perforating guns 300A, 300B.
Due to the protection afforded to switches 120, 520, and 620 by pressure bulkheads 160, 560 and the pressure bulkhead of igniter assembly 700, switches 120, 520, and 620 may be reused following the perforation of casing string 12 by perforating guns 300A, 300B so that switches 120, 520, and 620 may be employed in a plurality of separate and distinct completion operations. Given that the cost of manufacturing switches 120, 520, 620 may be relatively expensive compared to the cost of manufacturing the other components of switch sub 100, direct connect sub 500, and plug-shoot firing head 600, the ability to reuse switches 120, 520, 620 may reduce the cost of operating tool string 20 and perforating casing string 12. In some embodiments, pressure bulkheads 160, 560 and the pressure bulkhead of igniter assembly 700 may be sacrificial, and thus, not reused for multiple completion operations.
Referring still to
In this embodiment, following the actuation (via the closing of the FET in this example) of the safety switch 520 into the closed configuration, a second or enabling signal is transmitted from control system 15 to the combination switch 620 of plug-shoot firing head 600 via wireline 22 to enable combination switch 620 and thereby actuate combination switch 620 from an “open” configuration into a “closed” configuration. A third or arming signal is then transmitted from the control system 15 to the combination switch 620 via wireline 22 to arm combination switch 620 for initiating an igniter of igniter assembly 700 by closing an electronic shunt (e.g., an igniter FET) of the electrical circuit 624 of combination switch 620 which thereby completes a circuit path to the igniter of igniter assembly 700. A firing signal comprising electricity or electrical energy is then transmitted from control system 15 down wireline 22 to igniter assembly 700 to initiate the igniter of igniter assembly 700 and thereby actuate setting tool 30 and set frac plug 34 whereby fluid communication across frac plug 34 is restricted.
In this embodiment, following the actuation of setting tool 30 and the setting of frac plug 34, a fourth or arming signal is transmitted from the control system 15 to the combination switch 620 via wireline 22 to arm combination switch 620 for initiating the detonator 402 of lower detonator assembly 400B by closing an electronic shunt (e.g., a detonator FET) of the electrical circuit 624 of combination switch 620, thereby completing a circuit path to detonator 402. A firing signal comprising electricity or electrical energy is then transmitted from control system 15 down wireline 22 to the detonator 402 of lower detonator assembly 400B to thereby initiate detonator 402. The initiation of detonator 402 of lower detonator assembly 400B detonates the explosive shaped charges of lower perforating gun 300B, forming a first or lower set of perforations in casing string 12.
In this embodiment, following the detonation of the shaped charges of lower perforating gun 300B, a fifth or enabling signal is transmitted from control system 15 to the gun switch 120 of switch sub 100 to enable gun switch 120. A sixth or arming signal is then transmitted from the control system 15 to the gun switch 120 via wireline 22 to arm gun switch 120 for initiating the detonator 402 of upper detonator assembly 400A by closing an electronic shunt (e.g., a detonator FET) of the electrical circuit 124 of gun switch 120, thereby completing a circuit path to detonator 402. A firing signal comprising electricity or electrical energy is then transmitted from control system 15 down wireline 22 to the detonator 402 of upper detonator assembly 400A to thereby initiate detonator 402. The initiation of detonator 402 detonates the explosive shaped charges of upper perforating gun 300A, forming a second or upper set of perforations in casing string 12 that are spaced from the lower set of perforations formed by lower perforating gun 300B. In this embodiment, following the detonation of the shaped charges of upper perforating gun 300A, tool string 20 (sans frac plug 34) is retracted from wellbore 4 and the formation 6 is hydraulically fractured via a fluid delivered to formation 6 via the upper and lower sets of perforations formed in casing string 12 by perforating guns 300A, 300B.
While exemplary embodiments have been shown and described, modifications thereof can be made by one skilled in the art without departing from the scope or teachings herein. The embodiments described herein are exemplary only and are not limiting. Many variations and modifications of the systems, apparatus, and processes described herein are possible and are within the scope of the invention. For example, the relative dimensions of various parts, the materials from which the various parts are made, and other parameters can be varied. Accordingly, the scope of protection is not limited to the embodiments described herein, but is only limited by the claims that follow, the scope of which shall include all equivalents of the subject matter of the claims. Unless expressly stated otherwise, the steps in a method claim may be performed in any order. The recitation of identifiers such as (a), (b), (c) or (1), (2), (3) before steps in a method claim are not intended to and do not specify a particular order to the steps, but rather are used to simplify subsequent reference to such steps.
This application is a continuation of U.S. non-provisional patent application No. 16/786,445 filed Feb. 10, 2020, and entitled “Reusable Perforating Gun System and Method”, which claims benefit of U.S. provisional patent application No. 62/803,222 filed Feb. 8, 2019, and entitled “Digital Perforating Gun System” which is hereby incorporated herein by reference in its entirety.
Number | Date | Country | |
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62803222 | Feb 2019 | US |
Number | Date | Country | |
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Parent | 16786445 | Feb 2020 | US |
Child | 17157503 | US |