Patent Publication Number: US-2022235634-A1

Title: Perforating gun with detonation module

Description:
TECHNICAL FIELD 
     The present disclosure relates to devices and method for perforating a subterranean formation. 
     BACKGROUND 
     Hydrocarbons, such as oil and gas, are produced from cased wellbores intersecting one or more hydrocarbon reservoirs in a formation. These hydrocarbons flow into the wellbore through perforations in the cased wellbore. Perforations are usually made using a perforating gun that is generally comprised of a steel tube “carrier,” a charge tube riding on the inside of the carrier, and with shaped charges positioned in the charge tube. The gun is lowered into the wellbore on electric wireline, slickline, tubing, coiled tubing, or other conveyance device until it is adjacent to the hydrocarbon producing formation. Thereafter, a surface signal actuates a firing head associated with the perforating gun, which then detonates the shaped charges. Projectiles or jets formed by the explosion of the shaped charges penetrate the casing to thereby allow formation fluids to flow through the perforations and into a production string. 
     In certain instances, it may be desirable to use switches to selectively fire guns in a perforating tool. The present disclosure addresses the need to more efficiently assemble and/or transport such switches in a downhole tool. 
     SUMMARY 
     In aspects, the present disclosure provides an apparatus for selectively firing a perforating gun having a plurality of gun assemblies. The plurality of gun assemblies include at least a first gun and a second gun. The apparatus may include an end plate, a portion of a signal communication circuit, an initiator assembly, and an initiating element. The end plate has a cavity formed by at least a first passage intersecting a second passage. The first passage extends from a planar end face of the end plate and the second passage extends from a circumferential surface of the end plate. The portion of a signal communication circuit is disposed in the end plate and conveys signals between the first gun and the second gun. The initiator assembly is at least partially disposed in the first passage. The initiating element is sized to pass through the second passage. The initiating element is also configured to electrically couple to the portion of the signal communication circuit and to thermally couple to the initiator assembly when at least partially seated in the first passage. 
     In aspects, the present disclosure provides a related perforating apparatus. The perforating tool may include a first perforating gun having a first carrier having a first interior; a second perforating gun having a second carrier connectable to the first carrier, the second carrier having a second interior, the second carrier further having an opening communicating with the second interior; and a detonation module. The detonation module may include an end plate having a first passage and a second passage; a first electrical contact module positioned at a first end in the first passage; a second electrical contact assembly positioned at a second end in the first passage; and an addressable switch. The addressable switch may be seated in the second passage. The addressable switch includes a body and a seal disposed circumferentially around the body. The addressable switch electrically couples the first electrical contact assembly to the second electrical contact assembly when seated in the second passage. The opening of the second carrier rotationally and axially aligns with the second passage when the end plate is seated in the second carrier interior. 
     It should be understood that certain features of the invention have been summarized rather broadly in order that the detailed description thereof that follows may be better understood, and in order that the contributions to the art may be appreciated. There are, of course, additional features of the invention that will be described hereinafter and which will in some cases form the subject of the claims appended thereto. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       For detailed understanding of the present disclosure, references should be made to the following detailed description taken in conjunction with the accompanying drawings, in which like elements have been given like numerals and wherein: 
         FIG. 1  schematically illustrates a side sectional view of a perforating tool according to one embodiment of the present disclosure; 
         FIG. 2  sectionally illustrates a detonation module in accordance with one embodiment of the present disclosure; 
         FIG. 3  sectionally illustrates in greater detail a detonation module in accordance with one embodiment of the present disclosure; 
         FIGS. 4 and 5  illustrate the  FIG. 2  embodiment in different states of assembly; 
         FIG. 6  illustrates an “exploded” view of a perforating apparatus in accordance with one embodiment of the present disclosure; and 
         FIG. 7  illustrates another embodiment of a detonation module in accordance with the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     The present disclosure relates to devices and methods for perforating a formation intersected by a wellbore. The present disclosure is susceptible to embodiments of different forms. There are shown in the drawings, and herein will be described in detail, specific embodiments of the present disclosure with the understanding that the present disclosure is to be considered an exemplification of the principles of the disclosure, and is not intended to limit the disclosure to that illustrated and described herein. 
     Referring to  FIG. 1 , there is shown one embodiment of a perforating tool  100  in accordance with the present disclosure. The perforating tool  100  may include a first gun assembly  110  and a second gun assembly  112  aligned in an end to end fashion along a longitudinal axis  50 . Each gun assembly  110 ,  112  includes a carrier  111  that is shaped to receive a charge tube  114 . Each gun assembly  110 ,  112  also includes one or more shaped charges  115  fixed within the charge tube  114 . While two gun assemblies are shown, it should be understood that the perforating tool  100  may include three or more gun assemblies.  FIG. 2  is directed to a system for selectively firing gun assemblies. However, it should be understood that the teachings of the present disclosure may be applied to perforating tools that do not require selective firing. 
     Referring now to  FIG. 2 , there is shown a sectional side view of the perforating tool  100  in accordance with one embodiment of the present disclosure. To selectively fire a gun assembly within the perforating tool  100 , a firing signal is sent along a signal communication circuit formed along the perforating tool  100 . The firing signal may be an information-encoded signal and/or electrical energy having defined characteristic (e.g., voltage, amperage, duration, polarity, etc.). The signal communication circuit may include a detonation module  200  that is electrically and thermally coupled to the gun assembly  110  and electrically coupled to the gun assembly  112 . In some embodiments, the detonation module  200  may be provided with a programmable addressable switch to enable selective firing. 
     The perforating tool  100  includes guns  110 ,  112 electrically and thermally coupled to the gun assemblies  110 ,  112 , a signal communication circuit  116 , and one or more detonation modules  200 . The guns  110 ,  112  include carriers  111   a,    111   b,  respectively. The detonation module  200  provides a fluid-tight, pressure isolated environment for the guns  110 ,  112  and also forms a portion of the signal communication circuit  116  between the guns  110 ,  112 . In an embodiment, the detonation module  200  includes an end plate  202  that is positioned adjacent to a threaded connection  122  between the two guns  110 ,  112  and seats within the interiors  118 ,  120  of the guns  110 ,  112 , respectively. 
     The end plate  202  houses the components used to form the portion of the signal communication circuit  116  between the guns  110 ,  112 . The end plate  202  may include a body  205  in which are disposed a contact pin  207 , an electrical insulator  209 , and fastener  211 . The body  205  may be a cylindrical member having an outer circumferential surface  204 , a planar end face  231 , and a cavity  206 . The end plate  202  may include an alignment key  208  fixed on the outer surface  204  that is complementary to a keyway  210  formed along an inner surface  212  of the carrier  111   b.  The keyway  210  may be a slot, groove, or other similar surface depression that has a specified angular orientation relative to one or more features of the perforating gun  112 , e.g., an opening  214  in the circumferential wall of the carrier  111   b.  One or more seals  216  may be disposed on the outer circumferential surface  204  to contact the inner walls of the carriers  111   a,b  and thereby provide an interior of the carriers  111   a, b  that is fluid-tight and pressure isolated. Because the seals  216  are independent and are positioned in each carrier  111   a,b,  the end plate  202  provides a pressure seal between guns  110 ,  112  that remains sealed when either gun is detonated. 
     Referring to  FIG. 3 , the detonation module  200  forms the portion of the signal communication circuit  116  by using an addressable switch  220  and a contact module  222 . The cavity  206  of the end plate  202  includes a longitudinal passage  230  that intersects a transverse passage  232 . The longitudinal passage  230  extends from the planar end face  231  and is shaped and dimensioned to receive the contact module  222  and the transverse passage  232  extends from the circumferential surface  204  is shaped and dimensioned to receive the addressable switch  220 . The terms “longitudinal” and “transverse” refer to the direction in which the contact module  222  and the addressable switch  220 , respectively, enter the end plate  202 . That is, when fully assembled, the longitudinal passage  230  enables physical access, or communication, with the cavity  206  along a direction parallel with the longitudinal axis  50  ( FIG. 1 ) and the transverse passage  232  enables physical access, or communication, with the cavity  206  along a direction that is not parallel with the longitudinal axis  50  ( FIG. 1 ); e.g., perpendicular. The different directions of access to the cavity  206  enable personnel to access the cavity  206  after assembly as discussed below. Thus, the longitudinal passage  230  and the transverse passage  232  may simply be referred to as a first passage  230  and a second passage  232 . 
     The addressable switch  220  may be any conventionally constructed electrical device that, in response to a received signal, can output sufficient thermal energy to detonate an energetic material such as that used in a detonator cord (not shown) or a booster (not shown) and/or transmit, re-transmit, or otherwise convey an electrical signal. One class of switches are considered “select fire” switches because they can be programmed to initiate the firing of one perforating gun of a plurality of perforating guns or the firing of a sub-set of perforating guns of sets of perforating guns. The switch  220  may include analog and/or digital circuitry configured to receive and interpret signals. Interpreting signals may be as simple as recognizing polarity or comparing a received signal with a preprogrammed code or pattern. Irrespective of the configuration, the switch  220  either initiates the firing of the associated perforating gun or passes the signal to the next switch (not shown) based on the received signal. 
     In embodiments, the switch  220  may have a generally cylindrical body  260  in which are housed electrical circuitry (not shown) for receiving, processing, and transmitting firing signals. Generally, the electrical circuitry (not shown) determine whether a receiving signal is a firing signal for the associated perforating gun, here perforating gun  110  ( FIG. 1 ) or a firing signal for another perforating gun, e.g., a “pass through” signal. 
     To fire the perforating gun  110  ( FIG. 1 ), the switch  220  includes an initiating element  248  that projects out of an end  250  of the body  260 . The initiating element  248  applies activating energy for detonating an end of a detonator cord (not shown) or a booster (not shown) of the perforating gun  110  ( FIG. 1 ) in response to an activation signal (e.g., electrical energy). In some embodiments, the initiating element  248  may be formed of a metal that is resistant to electrical flow and generates heat when electrical current is applied. The initiating element  248  may act directly on and detonate the detonator cord end (not shown), which may be secured in a detonator cord holder  247 . In other embodiments, the initiating element  248  may act on the booster charge (not shown), which may be secured in a booster charge holder  249 . The detonator cord holder  247  and the booster charge holder  249 , if present, may be collectively referred to as an ‘initiator assembly.’ When fully assembled, the end of the detonator cord (not shown) or booster charge (not shown) may be in physical contact with or spatially separated from the initiating element (not shown). Nevertheless, these components are sufficiently close enough to be detonated by the thermal energy emitted by the initiating element  248 . Detonation of the booster charge (not shown) and/or the end of the detonator cord (not shown) carries the detonation to one or more shaped charges  116  ( FIG. 1 ) of the perforating gun  110  ( FIG. 1 ). 
     Contact pads or rings  262 ,  264  on the outer surface of the body  260  enable an electrical connection to be established with the electrical circuitry (not shown), to receive signals and to pass through signals, when required. Also, one or more seals  266  are disposed on the outer surface of the body  260  to form a fluid-tight seal with the surfaces defining the transverse passage  232 . The body  260  is engaged to the end plate  202  by complementary threads  268  formed on an outer surface of the body  260  and the inner surface defining the transverse passage  232 . A bolt head  270  or other suitable projection may be provided to apply torque or otherwise manipulate the body  260 . 
     In an arrangement, the contact module  222  may include a first contact assembly  240  that can be electrically coupled to the perforating gun  110  ( FIG. 1 ) and a second contact assembly  242  that can be connected to the second perforating gun  112  ( FIG. 1 ). In some arrangements, the contact module  222  may include a body  234  in which is formed a cavity  238  that receives the contact assemblies  240 ,  242 . The contact assemblies  240 ,  242  have ends  244 ,  246 , respectively, exposed to the cavity  238 . Each contact assembly  240 ,  242  may be attached to electrically conductive circuits (not shown) for their associated perforating guns  110 ,  112 , ( FIG. 1 ) respectively. Generally, the signal conducting elements along which a firing signal travels through the perforating tool  100  make up the portion of the signal communication circuit  116 . 
     The perforating tool  100  may be configured such that insertion of the addressable switch  220  and the integrated initiating element  248  into the transverse passage  232  effectively completes physical assembly of the perforating tool  100  and completes the signal communication circuit  116 . As noted previously, the signal communication circuit  116  is considered operative or complete if a firing signal can be conveyed along the signal communication circuit  116  between the guns  110 ,  112 . The remaining activities may include programming the addressable switch  220  and activities that do not require access to the interior of the perforating tool  100 . In one arrangement, the transverse passage  232  includes a shoulder  272  against which an enlarged diameter portion  274  of the addressable switch  220  seats. The position of the shoulder  272  is selected such that when the addressable switch  220  is seated thereon, the end  244  of the contact assembly  240  physically contacts the contact ring  262  and the end  246  of the contact assembly  242  physically contacts the contact ring  264 . Thus, for example, when the addressable switch  220  is threaded into the end plate  202 , having the enlarged diameter portion  274  physically contact the shoulder  272  ensures that the contact rings  262 ,  264  have established electrical connections with their respective contact assemblies  240 ,  242 . When so seated, the signal communication circuit  116  is complete; i.e., capable of transmitting information encoded signals between the guns  110 ,  112 . 
     Referring to  FIG. 4 , there is shown the perforating tool  100  without the addressable switch  220  ( FIG. 3 ) installed. However, the perforating guns  110 ,  112  may be otherwise assembled and include shaped charges  115 , detonator cords, wiring  290 ,  292 , etc. (not shown). To prevent debris or contaminants from entering the perforating tool  100 , a cap  280  may be used to close the opening  214  and/or the transverse passage  232 . For example, the cap  280  may be a disc that is press fit into the opening  214  or a lid that is screwed into the transverse passage  232 . In some situations, the perforating tool  100  may be configured as shown prior to transport from a manufacturing facility to a well site. 
     Referring to  FIG. 5 , after being transported to the well site and in preparation for deployment into a wellbore, the cap  280  of  FIG. 4  may be removed and the addressable switch  220  may be installed into the end plate  202  via the opening  214 . It should be appreciated that the wiring  290  ( FIG. 4 ) associated with the perforating gun  112  and the wiring  292  ( FIG. 4 ) associated with the perforating gun  110  have already been installed in the perforating tool  100 . Furthermore, the perforating gun  110  has already been connected to the perforating gun  112 . Thus, the addressable switch  220  has been inserted through the opening  214 , which is formed as a window in the circumferential wall of the carrier  111   b  ( FIG. 2 ). Insertion of the addressable switch  220  completes the physical electrical wiring for the signal communication circuit  116  and also positions the initiating element  248  close enough to the initiator assembly (e.g., the detonator cord holder  247  or the booster charge holder  249 ) to transfer sufficient thermal energy to fire the gun  110 . At this point, suitable devices such as a computing device may be used to program the addressable switch  220  with a code or “address” that uniquely identifies the perforating gun  110 . 
     Referring to  FIG. 3 , upon assembly, a signal from the surface may be communicated along the signal communication circuit  116  to the contact assembly  240  via wiring  292  ( FIG. 4 ) associated with the perforating gun  112  ( FIG. 1 ). The signal travels via the contact assembly  240  and the contact ring  262  to the circuitry (not shown) of the addressable switch  220 . 
     If the circuitry (not shown) determines that the signal is a firing signal for the perforating gun  110 , the circuitry (not shown) activates the initiating element  248 . If the circuitry (not shown) determines that the signal is not a firing signal for the perforating gun  110 , the circuitry (not shown) passes through the signal. By “passing through”, it is meant conveying the original signal without any modification, amplifying the original signal, partially processing and passing through the original signal, generating a new signal that carries the same information as the original signal, or combinations thereof. The passed through signal, travels via the physical contact between the contact ring  264  and the contact assembly  242  to wiring  290  associated with the perforating gun  112 . 
     Referring to  FIG. 6 , there is shown a side sectional view of the perforating tool  100  with the charge tube partially removed to better illustrate the features of the present disclosure. The perforating tool  100  may include a first gun assembly  110  and a second gun assembly  112 . Each gun assembly  110 ,  112  includes a carrier  111  that is shaped to receive a charge tube  114 . Each gun assembly  110 ,  112  also includes one or more shaped charges  115  ( FIG. 1 ) fixed within the charge tube  114 . To selectively fire a gun assembly within the perforating tool  100 , detonation modules  200 a,b are electrically and thermally coupled to the gun assemblies requiring selective firing. The addressable switches  220  ( FIG. 2 ) are not shown. Detonation module  200   b  is shown with the cap  280 . While two detonation modules are shown, fewer or greater may be used. 
     Detonation module  200   a  is shown in an “exploded” view between a pin end  300  of the gun assembly  110  and the box end  302  of the gun assembly  112 . The pin end  300  has an circumferential rim  304  and the box end  302  has an circumferential interior shoulder  306 . The end plate  202  has a circumferential annular shoulder  308  and a second circumferential shoulder  310 . When inserted into the interior  120  of the gun assembly  112 , the second circumferential shoulder  310  contacts the circumferential interior shoulder  306 . When the pin end  300  is inserted into the box end  302 , the rim  304  contacts the first circumferential shoulder  308 . When the end plate  202  is compressively secured between the rim  304  and the interior shoulder  306 , the opening  214  is rotationally and axially aligned with the transverse passage  232 . Thus, an unobstructed path is now available to insert the addressable switch  220  ( FIG. 2 ) into the detonation module  200   a.  It should be appreciated that components internal to the gun assemblies  110 ,  112  are not disassembled or otherwise disturbed during insertion of the addressable switch  220  ( FIG. 2 ). In particular, the wiring to the detonation module  200  may have already been made at an earlier time. 
     Referring to  FIG. 7 , there is shown another embodiment of a detonation module  200  according to the present disclosure. As in previous embodiments, the detonation module  200  provides a fluid-tight, pressure isolated environment for the guns  110 ,  112  ( FIG. 1 ) and also forms a portion of the signal communication circuit  116  between the guns  110 ,  112  ( FIG. 1 ). As also in previous embodiments, the detonation module  200  includes an end plate  202  that is configured in generally the same manner as previously discussed. As discussed below, in the  FIG. 7  embodiment, the electrical connections are performed during assembly of the perforating tool  100  ( FIG. 1 ) and the thermal connection may be completed at a later time. 
     The detonation module  200  forms a signal communication interface by using a contact module  322 . In some embodiments, an addressable switch  220  may be used to energize an initiator assembly  324 . 
     In one embodiment , the contact module  322  may include a block  224  disposed in a cavity  206  of the end plate  202 . The block  224  includes a first passage  230  that intersects a transverse second passage  232 . The first passage  230  is shaped and dimensioned to receive the addressable switch  220  and an initiator assembly  324  and the second passage  232  is shaped and dimensioned to receive a detonator  326 . 
     The contact module  322  may also include an input contact  342  that can be electrically coupled to the perforating gun  110  ( FIG. 1 ) and an output contact  344  that can be electrically connected to the second perforating gun  112  ( FIG. 1 ) via a insulated contact pin  340 . The input contact  342  is electrically coupled to the addressable switch  220 . Detonator contacts  346  electrically couples the addressable switch  220  to the contacts  327  of the detonator  326 . A transfer contact  348  electrically couples the addressable switch  220  to the output contact  344 . The contacts  342 ,  344 ,  346 ,  348  may be an assembly of electrical wires, contact pads, clips, biased connections, strips, soldered connections, etc. 
     In a non-limiting arrangement, the contact  342  may include wires electrically coupled to a contact pin (not shown) associated with the perforating gun  110  ( FIG. 1 ). The contacts  346  may be flexible conductive metal strips that compressively contact the contacts  327  of the detonator  326 . The contacts  327  may be circumferential strips positioned to contact the contacts  346  after the detonator  326  is seated in the end cap  202 . The contacts  348  and  344  may also be flexible conductive metal strips that compressively contact one another when the addressable switch  220  is seated in the end cap  202 . 
     Generally, the detonator  326  is configured to fire the perforating gun  110  ( FIG. 1 ) by energizing an initiating element  352 . The initiating element  352  applies activating energy for detonating an end of the detonator cord (not shown) or a booster (not shown) of the perforating gun  110  ( FIG. 1 ) in response to a activation signal (e.g., electrical energy). The detonator cord end (not shown) and a booster (not shown) may be secured within the initiator assembly  324 . One or more seals  216  disposed on the detonator  326  may be used to seal the second passage  232 . 
     The use of the  FIG. 7  embodiment is the same as the previously described embodiments of detonation modules. 
     After being transported to the well site and in preparation for deployment into a wellbore, the cap  280  of  FIG. 4  may be removed if present and the detonator  326  may be installed into the end plate  202  via the opening  214  ( FIG. 3 ). It should be appreciated that all internal wiring associated with the perforating guns has already been installed in the perforating tool  100 . 
     In one mode of use, the perforating tool  100  ( FIG. 1 ) is assembled without the detonator  326  and associated initiating element  352 . However, the perforating guns  110 ,  112  ( FIG. 1 ) may be otherwise assembled and include shaped charges, detonator cords, addressable switch  220 , the contact module  322 , etc. Thus, insertion of the detonator  326  electrically couples the detonator  326  to the addressable switch  220  and thermally couples the initiating element  352  to the initiator assembly  324 , which enables the firing of the perforating gun  110  ( FIG. 1 ). It should be noted that access to the internal areas of the perforating guns  110 ,  112  ( FIG. 1 ) was not needed to complete assembly. Also, suitable devices such as a computing device may be used to program the addressable switch  220  with a code or “address” that uniquely identifies the perforating gun  110 . To prevent debris or contaminants from entering the perforating tool  100  ( FIG. 1 ), a cap  280  ( FIG. 4 ) as previously described may be used. 
     In another mode of use, the perforating tool  100  ( FIG. 1 ) is assembled without the detonator  326  and associated initiating element  352 . However, the perforating guns  110 ,  112  ( FIG. 1 ) may be otherwise assembled and include shaped charges, detonator cords, the contact module  322 , etc. The addressable switch  220  may be replaced with an electrical circuit (not shown) that communicates electrical energy to the initiating element  352 . Because no addressable switch is used, there is no need to code or “address” any switch. Further, the firing signal may not include information-encoded signals but simply electrical power having defined characteristics (e.g., voltage, time duration, polarity, amperage, etc.). Such embodiments may be used when all guns are to be fired using a single surface transmitted firing signal, when only one gun is used, when one detonation train is used to fire multiple guns, or other situations that do not require selective firing. Insertion of the detonator  326  electrically couples the detonator  326  to the portion of the signal communication circuit  116  and thermally couples the initiating element  352  to the initiator assembly  324 , which enables the firing of the perforating gun  110  ( FIG. 1 ). It should be noted that access to the internal areas of the perforating guns  110 ,  112  ( FIG. 1 ) was not needed to complete assembly. To prevent debris or contaminants from entering the perforating tool  100  ( FIG. 1 ), a cap  280  ( FIG. 4 ) as previously described may be used. 
     As used in this disclosure, the terms “aligned” means co-linear or concentric. Thus, axes that are aligned are concentric. Axes that are misaligned or eccentric are separated by a predetermined distance. As used in this disclosure, terms such as “substantially,” “about,” and “approximately” refer to the standard engineering tolerances that one skilled in the art of well tools would readily understand. 
     As used throughout, an “electrical connection” or “electrical engagement” is a connection wherein electrical signals are conveyed between two or more objects. Physical contact between the two bodies may or may not be present. Also, the terms “gun” and “gun assembly” may be used interchangeably. 
     By electrically coupled, it is meant that the coupling or connection allows the transfer of information-encoded signals. By thermal connection or thermal coupling, it is meant having the end of the detonator cord (not shown) or booster charge (not shown) sufficiently close enough to an initiating element to be detonated by the thermal energy emitted by the initiating element. 
     The foregoing description is directed to particular embodiments of the present invention for the purpose of illustration and explanation. It will be apparent, however, to one skilled in the art that many modifications and changes to the embodiment set forth above are possible without departing from the scope of the invention. It is intended that the following claims be interpreted to embrace all such modifications and changes.