Downhole ignition assembly

Abstract

A downhole ignition assembly is described herein. The downhole ignition assembly has a switch capsule having a longitudinal axis, the switch capsule having a first portion housing a switch circuit in an orientation transverse to the longitudinal axis and a second portion contacting an igniter disposed in the second portion, the first portion having a contact in electrical contact with a tool coupled to the downhole ignition assembly.

Description

[0001] Cross-reference paragraphs

[0002] This application claims the benefit of U.S. Provisional Application No. 63 / 011,046 entitled “DOWNHOLE IGNITION ASSEMBLY”, filed April 16, 2020, the disclosure of which is incorporated herein by reference. Technical Field

[0003] The embodiments of the present invention generally relate to well perforation in oil and gas extraction. Specifically, embodiments of downhole ignition assemblies are described. Background Technology

[0004] Hydraulic fracturing is a practical operation used by geological resource producers, in which underground geological formations are subjected to hydraulic pressure to loosen the dense formations and facilitate the extraction of resources from them. Typically, the resources are liquid and / or gaseous hydrocarbons.

[0005] Perforating tools, sometimes called perforating guns, are used to prepare fracturing formations. The borehole wall is perforated by detonating explosive charges. The material is ejected into the well wall, creating an opening several inches to several feet long, depending on the explosive discharge and the local structure and composition of the formation. Hydraulic fluid can then be supplied to the opening and used to deliver the hydraulic shock.

[0006] Perforation is an example of a downhole tool that uses explosive charges. All of these tools require ignition. Electrically activated ignition assemblies are commonly used to ignite downhole explosive tools. A cable transfers electrical energy to a combustible element, igniting a ballistic discharge that detonates the explosive charge within the tool. Ignition assemblies are typically used once, then removed from the well and reassembled for future use. To avoid requiring numerous spare assemblies and the time and effort spent reassembling used ones, speed and ease of reassembly are paramount. An improved downhole ignition assembly is needed that is reliable and easy to reassemble after use. Summary of the Invention

[0007] The embodiments described herein provide a downhole ignition assembly including a switch container having a longitudinal axis, the switch container having a first portion and a second portion, the first portion accommodating a switch circuit in a direction transverse to the longitudinal axis, the second portion contacting an igniter disposed in the second portion, the first portion having contacts for tool electrical contact coupled to the downhole ignition assembly.

[0008] Other embodiments described herein provide a downhole ignition assembly including an ignition module coupled to a feedthrough module. The ignition module includes an ignition housing having an igniter and a switch assembly disposed within the ignition housing. The switch assembly includes a switch container housing a switch circuit that is electrically in contact with the igniter and the feedthrough module; an igniter contact that is electrically in contact with the switch circuit and the igniter; and a feedthrough contact electrically connected between the switch circuit and a feedthrough member of the feedthrough module.

[0009] Other embodiments described herein provide an ignition module for a downhole ignition assembly, the ignition module including an ignition housing having a housing and a central channel extending from a base plate of the housing; and a switching assembly disposed in the housing and extending along the central channel for energizing an igniter, the switching assembly having a grounding path bypassing the ignition housing. Attached Figure Description

[0010] Therefore, the above-described features of this disclosure can be understood in detail, and a more specific description of this disclosure, as outlined above, can be obtained by referring to the embodiments, some of which are illustrated in the accompanying drawings. However, it should be noted that the drawings only illustrate exemplary embodiments and should not be considered as limiting its scope; other equivalent embodiments are permissible.

[0011] Figure 1 This is an exploded view of a downhole ignition assembly according to one embodiment.

[0012] Figure 2 yes Figure 1 A cross-sectional view of the downhole ignition assembly.

[0013] Figure 3 This is a cross-sectional view of a downhole ignition assembly according to another embodiment.

[0014] For ease of understanding, the same reference numerals are used where possible to denote the same elements common in the figures. It is contemplated that elements and features of one embodiment can be advantageously incorporated into other embodiments without further description. Detailed Implementation

[0015] Figure 1This is an exploded side view of a downhole ignition assembly 100. The ignition assembly 100 is used to ignite downhole tools using explosive charges. The ignition assembly 100 typically includes an ignition module 101 that engages with a feedthrough module 124. The feedthrough module 124 is any module that typically implements electrical feedthrough to the ignition module 101; it can be a tool utilizing ballistic ignition provided by the ignition module 101, or it can simply be an electrical feedthrough module. The ignition module 101 is characterized by an ignition housing 102 that houses a switch assembly 104 and an igniter 106. The switch assembly 104 has a switch container 108 having a first portion 109 that houses an electrical switch 110. The switch container 108 also has a second portion 112 extending from the first portion 109, housing the igniter 106, and having electrical contact with the igniter 106. The first portion 109 has a larger diameter than the second portion 112. The diameter of the second part 112 is generally similar to the diameter of the igniter 106 housed within the second part 112 to simplify electrical contact between the second part 112 and the igniter 106. The switch assembly 104 is nested with the ignition housing 102. The downhole ignition assembly 100 is generally cylindrical with a longitudinal axis 120, and each component of the assembly 100 is generally cylindrical, with its center, cylinder, or longitudinal axis coinciding with the longitudinal axis 120 of the assembly when the components are assembled.

[0016] Switch 110 includes a circuit board 114 that carries the circuitry constituting the switch. Circuit board 114 is typically nested within a first portion 109 in an orientation transverse to the longitudinal axis 120. An ignition contact 116 extends from a first side of circuit board 114, and a feedthrough contact 118 extends from a second side of circuit board 114 opposite the first side. Feedthrough contact 118 typically connects circuit board 114 to a power source. In this case, feedthrough contact 118 connects to a feedthrough member 122 of feedthrough module 124, which transmits electrical pulses and / or signals to other electrical switches and / or signaling devices. Feedthrough member 122 is surrounded by an insulator 123, and both are contained within a feedthrough housing 125, defining the main components of feedthrough module 124. Here, feedthrough module 124 is shown as a purely electrical feedthrough member separate from ignition module 101; however, feedthrough module 124 can be part of an ejection tool, such as a perforating gun tool. The feedthrough module 124 is nested with the switch assembly 104 and the ignition housing 102, and can also be nested with other tools.

[0017] An optional backplate 115 may be included to enclose the circuit board 114 within the first portion 109 of the switch container 108. Figure 1The backplate 115 has a central opening for mounting around the feedthrough contact 118, allowing it to be fitted into the first portion 109 of the switch housing 108. The backplate 115 may have alignment features that help stabilize the orientation of the circuit board 114 within the switch housing 108. The backplate 115 is optional in some embodiments where it is not used, while it is used in other embodiments.

[0018] To assemble the downhole ignition assembly 100, an igniter contact 116 is connected to a switch container 108, and an igniter 106 is attached to the igniter contact 116, forming a subassembly. In one embodiment, the igniter contact 116 is a threaded member, and the igniter 106 is screwed onto the igniter contact 116. The subassembly is disposed within the switch container 108, and the feedthrough contact 118 and feedthrough plug 230 ( Figure 2 A switch assembly 104 is mounted to form a switch assembly 104, which is in turn housed within an ignition housing 102. A feedthrough member 122 is coupled to a feedthrough contact 118 to connect the switch assembly 104 to another tool. The ignition housing 102 can be secured to the feedthrough module 124 via a threaded connection to the feedthrough housing 125, or the ignition housing 102 can be secured to a gun component or another component via a threaded connection or other fasteners that securely hold the switch assembly 104 in place.

[0019] Figure 2 It is in the assembly and configuration stage. Figure 1 A cross-sectional view of the downhole ignition assembly 100. The ignition housing 102 has a central channel 202 that accommodates a second portion 112 of an igniter 106 and a switch container 108. The central channel 202 has an inner diameter larger than the outer diameter of the second portion 112 and larger than the diameter of the igniter 106. Therefore, when the igniter 106 and the switch assembly 104 are disposed in the ignition housing 102, a first annular gap 204 having a first width is defined by the inner wall 206 of the central channel 202 and the outer wall of the second portion 112, and a second annular gap 208 having a second width greater than the first width is defined by the inner wall 206 and the igniter 106, both of which are coaxially positioned with respect to the central channel 202.

[0020] The first portion 109 has a larger diameter than the second portion 112. The ignition housing 102 has a reservoir 210 for receiving the first portion 109 of the switch container 108. A central channel 202 of the ignition housing 102 extends from the central region of the reservoir 210, such that the switch container 108 is fitted within the reservoir 210. Here, the reservoir 210 is manufactured such that its diameter matches the outer diameter of the first portion 109, such that the first portion 109 is nested within the reservoir 210. The base plate portion 212 of the first portion 109 generally contacts the base plate portion 214 of the reservoir 210, while the second portion 112 of the switch container 108 extends into the central channel 202.

[0021] The igniter 106 is provided with a contact flange 218, which can be an integral part of the igniter 106 or a separate component. The contact flange 218 can also be a ridge extending radially outward from the core of the igniter 106. In this case, the contact flange 218 has a truncated conical shape, with its diameter increasing in the direction away from the igniter contact 116. The wide end 222 of the contact flange 218 abuts against a lip 224 at the end 226 of the second portion 112 opposite to the first portion 109. The narrow end 228 of the contact flange 218 opposite to the wide end 226 contacts the core of the igniter 106. If desired, the lip 224 can be omitted, and the contact flange 218 can contact only the inner wall of the second portion 112 without the lip 224.

[0022] The feedthrough contact 118 is typically a cylindrical member. A first end 234 of the feedthrough contact 118 contacts the circuit board 114. A feedthrough plug 230 is nested with a second end 236 of the feedthrough contact 118 opposite the first end 234. The feedthrough plug 230 is a conductive member with a truncated conical shape that accommodates the contact end 232 of the feedthrough member 122. The feedthrough plug 230 has a first end 238 with a diameter larger than the maximum diameter of the contact end 232 to allow for precise and easy connection between the contact end 232 and the feedthrough plug 230. The feedthrough plug 230 has a flange 240 at the first end 238 to maintain reliable contact with the second end 236 of the feedthrough contact 118. The diameter of the feedthrough plug 230 decreases from the first end 238 to the second end 242 to provide reliable electrical contact with the contact end 232 of the feedthrough member 122. An optional backplate 115 is shown mounted only within the first portion 109 of the switch housing 108. The backplate 115 can be held in place by friction against the wall of the first portion 109.

[0023] Contact flange 218 contacts the fire head 106 and the switch container 108. In this configuration, contact flange 218 and switch container 108 are conductive. Switch container 108 has a flange 244 at the edge of its first portion 109, which contacts the feedthrough housing 125 when assembled. (See again) Figure 1 In this configuration, flange 244 has a rounded projection form, configured as an open edge of switch housing 108, with periodic notches around its circumference. Flange 244 can have any form that provides support for switch assembly 104 and contacts feedthrough housing 125 or any other compatible tool. For example, flange 244 can be a smooth, continuous edge, or flange 244 can be configured as several tabs spaced apart around the edge of switch housing 108, or even a pointed tip. Here, the tabs are shown as square at the ends, but the tabs can be rounded. In some cases, flange 244 can be configured to enhance conductivity, for example by coating or electroplating with a material of higher conductivity. If desired, small rings, fine lines, or even several small dots of such highly conductive material (e.g., gold) can be plated around the periphery of flange 244 to enhance its conductivity. It should be noted that in the case where flange 244 has notches, backplate 115 may include tabs that frictionally engage with the notches to hold backplate 115 in place, such as... Figure 1 As shown.

[0024] Refer again Figure 2 As described above, the ignition housing 102 also contacts the switch housing 108 and the feedthrough housing 125. Thus, all electrical components of the ignition assembly 100, including the ignition housing 102, the switch assembly 104, and the igniter 106, are grounded to the feedthrough module 124 via the feedthrough housing 125 in this case. Therefore, the switch housing 108 is made of or coated with a conductive material such as steel or brass. This provides the advantage that the grounding path of the ignition assembly 100 bypasses the ignition housing 102, allowing the ignition assembly 100 to be removed from a well, taken from a tool string, fitted with a new igniter, and installed on a new tool string with minimal or no cleaning required to establish electrical contact with the new tool string. Furthermore, the assembly described herein does not require wiring connections. Finally, as described above, the assembly can be quickly constructed by attaching the igniter 106 to the igniter contact 116, placing the resulting sub-assembly into the switch container 108, placing the switch container 108 with the switch assembly into the ignition housing 102, adding the feedthrough contact 118 and the plug 230, and attaching the resulting ignition module to the feedthrough module 124, or to a tool having the feedthrough component 122, by connecting the feedthrough component 122. Using the embodiments described herein, the speed and accuracy of assembling ignition-activated downhole tools are improved. The embodiments described herein also require less cleaning at the well site.

[0025] Flange 244 extends radially outward a short distance from the first portion 109 of switch container 108, but does not contact the head housing 102. Figure 2The diagram also shows a flange 244 angled toward the feedthrough housing 125 to contact the feedthrough module 124 when the contact end 232 of the feedthrough member 122 is within the feedthrough plug 230. In an alternative embodiment, the flange 244 may have a length that provides contact with the ignition housing 102 in addition to the feedthrough housing 125. The flange 244 may have a segmented or curved profile to conform to the profile of the feedthrough module 124 or the ignition housing 102. In other embodiments, a tabbed form may extend to the first portion 109 such that tabs or tips extend upward from the second portion 112 around the circuit board 114 to form the flange 244. For example, in one embodiment, three tips may extend upward from the top of the second portion 112 around the circuit board to form the flange 244. In such an embodiment, the switch container 108 would be formed by the second portion 112 with three tips extending upward from the second portion 112 to form the flange 244. In another related embodiment, a single pointed or thick wire may extend from the second portion 112 around the circuit board 114 to contact the feedthrough module 124 or other compatible tool. In this embodiment, the switch assembly 104 also does not have a switch housing, but only a contact member comprising an igniter portion and a contact point. In such an embodiment, the positioning of the circuit board 114 can be provided using a pin inserted into a hole in the base portion 214 of the ignition housing 102 or other convenient means.

[0026] Figure 3 This is a cross-sectional view of a downhole ignition assembly 300 according to another embodiment. Figure 3 The embodiments are similar in most respects Figure 2 An embodiment. The electrical connection from the feedthrough member 122 is in Figure 3 In different embodiments, it is provided in a different manner. Instead of the feedthrough contact 118 and feedthrough plug 230, a conductive elastic member 342 is electrically connected to the circuit board 114 in the central region of the circuit board 114 and electrically connected to the igniter contact 116 through the circuit board 114. The elastic member 342 has a first end 334 and a second end 336 opposite to the first end 334, in which case the first end 334 is in direct physical contact with one end of the igniter contact 116 disposed through the circuit board 114. Figure 3 In this design, an alternative backplate 315 is used, which has a support extension 318 for supporting the elastic member 342 and preventing the elastic member 342 from bending excessively laterally.

[0027] A contact cap 330 may be disposed at the second end 336 of the elastic member 342 to provide enhanced electrical contact with the elastic member 342. The contact cap 330 is conductive and has a flanged truncated conical shape to nest within the generally circular second end 336 of the elastic member 342. This flange supports the contact cap 330 at the second end 336 of the elastic member 342. When the feedthrough module 124 and the ignition module 101 are assembled, the contact cap 330 makes electrical contact with the feedthrough member 122. When the feedthrough module 124 moves to its attachment position with the ignition housing 102, the feedthrough member 122 presses down the contact cap 330 and compresses the elastic member 342. The reaction force of the compressed elastic member 342 maintains reliable electrical contact between the elastic member 342, the contact cap 330, the feedthrough member 122, and the circuit board 114.

[0028] The elastic member 342 can be any convenient type of spring. A coil spring or a leaf spring can be used. The leaf spring has a lateral bending member to provide elasticity as the length of the elastic member 342 changes. In an alternative embodiment, the elastic member 342 can be electrically connected to the circuit board 114 and the igniter contact 116 via conductive contacts disposed in a circuit board between the elastic member 342 and the igniter contact 116.

[0029] The contact cap 330 and the second end 336 can be shaped in any advantageous manner to enhance contact. For example, the contact cap 330 can have a cylindrical extension with a flange at the top. In another example, the contact cap 330 can be larger than... Figure 3 The length shown has an extending cylindrical, conical, or truncated conical length that projects downward within the elastic member 342. The contact cap 330 may also be integrally formed with the elastic member 342, meaning the elastic member 342 may have a contact or cap formed at the second end 336. In one embodiment, an elastic contact that can replace the elastic member 342 and the contact cap 330 may have a first contact at the first end 334 for contacting the circuit board 114 or the ignition contact 116, a second contact at the second end 336 for contacting the feedthrough member 122, and an elastic portion between the first and second contacts, which may be any convenient type of spring.

[0030] The support extension 318 of the back plate 315 may have a ledge 320 at its free end that restricts the movement of the contact cap 330. When assembling the switch assembly characterized by the contact cap 330 and the support extension 318, the contact cap 330 is located at the end of the elastic member 342, and the back plate 315 is mounted such that the support extension 318 surrounds the elastic member 342. The ledge 320 contacts the contact cap 330 around its edge, presses down the contact cap 330, and compresses the elastic member 342, so that the contact cap 330 rests against the ledge 320. When the feedthrough module 124 is subsequently assembled to the ignition module 101, as the switch assembly 104 is installed, the contact end 232 of the feedthrough member 122 is pushed against the contact cap 330 into the support extension 318 of the back plate 315, pressing down the contact cap 330 and further compressing the elastic member 342, thereby creating a space between the contact cap 330 and the ledge 320, such as Figure 3 As shown. In this way, as long as the back plate 315 is in the proper position, the elastic member 342 and the contact cap 330 are prevented from disengaging from the switch assembly 104.

[0031] In all embodiments shown here, the grounding of igniter 106 and the circuitry supplying power to igniter 106 are provided to feedthrough housing 125 via the second portion 112 of switch container 108 and via flange 244. This configuration simplifies field operations by allowing for rapid reassembly and reuse of ignition module 101 without requiring extensive cleaning when the component is brought to the surface, as the grounding of the ignition circuitry is independent of its connection to the housing of the ignition assembly.

[0032] While the foregoing describes embodiments of the present invention, other and further embodiments of the present disclosure may be devised without departing from the basic scope of the present disclosure, the scope of which is determined by the appended claims.

Claims

1. A downhole ignition assembly, comprising: A switch container having a longitudinal axis, the switch container having a first part and a second part, the first part accommodating a switch circuit in an orientation transverse to the longitudinal axis, the second part having an igniter disposed in the second part, the second part being disposed in an ignition housing, the first part having a contact for a tool electrical contact coupled to a downhole ignition assembly, wherein the ignition housing has a housing, the first part of the switch container being nested within the housing, and the switch container having a flange at the edge of the first part providing a grounding path bypassing the ignition housing.

2. The downhole ignition assembly of claim 1, wherein the igniter is attached to an electrical contact that provides electrical communication between the igniter and a switching circuit.

3. The downhole ignition assembly according to claim 2 further includes an ignition housing of the first part of the contact switch container.

4. The downhole ignition assembly according to claim 2 further includes a cylindrical feedthrough contact attached to the switching circuit.

5. The downhole ignition assembly according to claim 2 further includes a resilient contact attached to the switching circuit.

6. The downhole ignition assembly according to claim 4 or 5, further comprising a backplate disposed in the first part of the switch container.

7. A downhole ignition assembly, comprising: An ignition module connected to the feedthrough module, the ignition module comprising: The ignition housing has an ignition device and a switching assembly disposed within the ignition housing, the switching assembly comprising: A switch container that houses a switch circuit, the switch container being in electrical contact with an igniter and a feedthrough module, the switch container providing a grounding path bypassing an ignition housing, and the switch container having a first portion that houses the switch circuit and a second portion that houses and is in electrical contact with the igniter to provide a grounding path, the second portion being disposed within the ignition housing; Ignition contacts that are in electrical contact with the switching circuit and the igniter; and A feedthrough contact is electrically connected between a switching circuit and a feedthrough component of a feedthrough module, the feedthrough module including an insulator surrounding the feedthrough component. The ignition housing has a housing, and a first part of the switch container is nested within the housing. The switch container has a flange at the edge of the first part that provides a grounding path bypassing the ignition housing.

8. The downhole ignition assembly according to claim 7, wherein the switching circuit is a circuit board positioned transversely to the longitudinal axis of the ignition assembly.

9. The downhole ignition assembly of claim 7, wherein the switch container has a first portion for receiving a switch circuit and a second portion for receiving and electrically contacting the igniter.

10. The downhole ignition assembly of claim 7, wherein the switch container provides a grounding path bypassing the ignition housing.

11. The downhole ignition assembly of claim 10, wherein the switch container has a first portion for receiving a switch circuit and a second portion for receiving and electrically contacting the igniter to provide a grounding path.

12. The downhole ignition assembly of claim 11, wherein the flange is used for electrical contact with the feedthrough housing of the feedthrough module.

13. The downhole ignition assembly of claim 12, wherein the feedthrough contact is an elastic member.

14. The downhole ignition assembly of claim 12, wherein the ignition housing further has a central channel extending from the base plate of the housing, a first portion of the switch container contacts the base plate of the housing, and a second portion of the switch container extends along the central channel of the ignition housing.

15. The downhole ignition assembly of claim 14, wherein the feedthrough contact is an elastic member.

16. An ignition module for a downhole ignition assembly, the ignition module comprising: An ignition housing having a housing and a central channel extending from the base plate of the housing; and A switching assembly, disposed within the housing and extending along a central channel, is used to energize the igniter. The switching assembly has a grounding path that bypasses the ignition housing. The switch assembly includes a switch housing having a first portion that houses the switch circuit and a second portion that holds and electrically contacts the igniter, wherein the first portion of the switch housing is nested within the housing and has a flange that provides a grounding path bypassing the ignition housing, and the second portion is disposed within the ignition housing.

17. The ignition module of claim 16, wherein the switching assembly includes an ignition contact electrically connecting the igniter to the switching circuit and a feedthrough contact electrically connecting the switching circuit to a power source.

18. The ignition module according to claim 17, wherein the feedthrough contact is an elastic member.

19. The ignition module of claim 18, further comprising a backplate engaged with the first portion of the switch container.

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