Patent Application
20190292886
This disclosure generally relates to a detonator for use with a perforating gun system. More specifically, the detonator is capable of being fluid-disabled in the event that the perforating gun system leaks or is flooded with a fluid.
Perforating gun assemblies are used to generate holes in steel casing pipe/tubing and/or cement lining in a wellbore to gain access to the oil and/or gas formation. During the process of perforating the oil and/or gas formation, the perforating gun assembly is lowered into and positioned properly in the wellbore. Typical perforating gun assemblies include a carrier and a plurality of shaped charges housed in the carrier. The shaped charges are initiated to create holes in the casing and to blast through the formation so that the hydrocarbons can flow through the casing. Each shaped charge is connected to each other via a detonation cord. The detonation cord is typically coupled to a detonator, such as percussion detonator or an electrical detonator. Electrical detonators typically include hot-wire detonators, semiconductor bridge detonators, or exploding foil initiator (EFI) detonators. Once the detonator is activated/initiated, the detonator begins a sequence of events that initiate the detonation cord, and thereby the shaped charges of the perforation gun assembly.
The perforating gun assembly may spend some time in the fluid-filled environment of the wellbore prior to the initiation of the detonator, and thus the shaped charges. If the gun assembly develops a leak which allows wellbore fluids to enter the perforating gun assembly, several undesirable things may occur, including severe damage to the perforating gun assembly. The assembly may misfire, only partially fire, fire low-order and thereby split/burst open and plug/obstruct the wellbore, and the like.
In view of the continually increasing safety requirements and the problems described hereinabove, there is a need for a detonator for use in a perforating gun system that provides additional precaution against the firing of the perforating gun system when there is a potential leakage of fluid in the perforating gun system. Furthermore, there is a need for a detonator this is capable of being fluid-disabled/fluid desensitized in the presence of fluids in the perforating gun system. Additionally, there is a need for a detonator that facilitates the entry of fluids into the detonator to abort the firing sequence of the perforating gun system.
According to an aspect, the present disclosure may be associated with a detonator for use with perforating gun assemblies. The detonator includes a shell having a closed end, an open end, and a hollow interior between the closed and open ends. One or more openings extend through the shell from the hollow interior. The detonator includes a non-mass explosive body disposed within the hollow interior. The non-mass explosive body includes a head portion and a leg portion opposite the head portion. One or more channels are formed between the head portion and the leg portion, and are in fluid communication with the openings. A main explosive load is disposed at the closed end of the shell, and is sandwiched between the closed end and the head portion. The openings, in combination with the channels, are configured to introduce fluids, such as wellbore fluids, into the non-mass explosive body to disable the detonator.
The present disclosure further describes the detonator including a cylindrical plug positioned at the open end of the shell and at least partially disposed in the hollow interior. The plug includes an elongated opening that extends along a length of the plug. The elongated opening facilitates communication of the fluid(s) into the shell, and to the non-mass explosive body. According to an aspect, the elongated opening and the channels are configured to introduce the fluid into the non-mass explosive body to disable the detonator.
According to an aspect, the detonators described hereinabove are particularly suited for use in a perforating gun system/perforating gun assembly.
The present embodiments also relate to a method of using a detonator in a wellbore. The method includes positioning the detonator within a perforation gun system. The detonator is substantially as described hereinabove, and includes a shell having a closed end, an open end, and a hollow interior extending between the closed and open ends. A main explosive load is disposed within the hollow interior and a non-mass explosive body abuts the main explosive load. A cylindrical plug including an elongated opening may be positioned at the open end of the shell and may be at least partially disposed within the hollow interior. The method includes lowering the perforating gun system into the wellbore, and initiating the detonator to trigger an explosive reaction. According to an aspect, in the event that fluid has leaked into or flooded the perforating gun system, the openings of the shell in combination with channels, alternatively the elongated opening of the cylindrical plug and the channels of the non-mass explosive body, introduces the fluid into the non-mass explosive body to disable the detonator.
A more particular description will be rendered by reference to specific embodiments thereof that are illustrated in the appended drawings. Understanding that these drawings depict only typical embodiments thereof and are not therefore to be considered to be limiting of its scope, exemplary embodiments will be described and explained with additional specificity and detail through the use of the accompanying drawings in which:
Various features, aspects, and advantages of the embodiments will become more apparent from the following detailed description, along with the accompanying figures in which like numerals represent like components throughout the figures and text. The various described features are not necessarily drawn to scale, but are drawn to emphasize specific features relevant to some embodiments.
The headings used herein are for organizational purposes only and are not meant to limit the scope of the description or the claims. To facilitate understanding, reference numerals have been used, where possible, to designate like elements common to the figures.
Reference will now be made in detail to various embodiments. Each example is provided by way of explanation, and is not meant as a limitation and does not constitute a definition of all possible embodiments.
As used herein, “fluid-disabled” means that if a perforating gun has a leak and fluid enters the perforating gun, a detonator of the perforating gun system is disabled/deactivated by the presence of the fluid, which breaks the explosive train. This prevents the perforating gun from potentially splitting/bursting open while inside a wellbore, and potentially plugging the wellbore.
For purposes of illustrating features of the embodiments, reference will be made to various figures.
Embodiments of the disclosure may be associated with a detonator/fluid-disabled detonator 10. According to an aspect, and as illustrated in
A main explosive load 28 is disposed within the hollow interior 26 of the shell 20. As illustrated in
A non-mass-explosive (also referred to herein as a NME) body is 30 is disposed in the hollow interior 26 of the shell 20, adjacent the main explosive load 28. As illustrated in
The head portion 32 of the non-mass explosive body 30 includes a primary explosive 31. The primary explosive 31 may be embedded within the head portion 32 in such a manner that protects the primary explosive 31 from being unintentionally initiated. As would be understood by one of ordinary skill in the art, explosives of typical detonator assemblies may be unintentionally initiated due to shock, impact and/or any friction forces. A secondary explosive 33 abuts the primary explosive 31, and seals the primary explosive 31 within the head portion 32. The primary and secondary explosives 31, 33 collectively have a total thickness T of about 3 mm to about 30 mm, alternatively about 3 mm to about 10 mm. The secondary explosive 33 may be configured as a layer of an explosive material. According to an aspect, the primary explosive 31 includes at least one of lead azide, silver azide, lead styphnate, tetracene, nitrocellulose, and BAX.
Each of the primary and secondary explosives 31, 33 have a safe temperature rating of above 150° C. (with the exception of PETN, which has a rating of approximately 120° C.). The secondary explosive 33 may include a material that is less sensitive to initiation, as compared to the primary explosive 31. The secondary explosive 33 may include at least one of PETN, RDX, HMX, HNS and PYX. In an embodiment, the secondary explosive 33 may be less sensitive to initiation than PETN. As would be understood by one of ordinary skill in the art, the sensitivities of the primary and secondary explosives 31, 33 refer to the degree to which they can be initiated by impact (Nm), heat, friction (N) or other forms of mechanical forces. Since the secondary explosive 33 has a lower degree of sensitivity than the primary explosive 31, it is not required for the secondary explosive 33 to be housed within an additional NME type safety body within the shell 20, in order to avoid an unintentional initiation by an external mechanical force.
One or more channels 36 are arranged between the head and leg portions 32, 34. As illustrated in
The channels 36 include a first channel 37 and a second channel 38. The first channel 37 extends along a lengthwise dimension of the detonator 10 (i.e., along the Y-axis of the detonator 10) a distance from about 0.5 mm to about 5 mm, alternatively about 0.5 mm to about 3 mm. Alternatively, the second channel 38 extends along a transverse dimension of the detonator 10 (i.e., along the X-axis of the detonator 10) at a distance of about 0.5 mm to about 5 mm, alternatively about 1 mm to about 3 mm. When the channels 36 include the first and second channels 37, 38, the first channel 37 and the second channel 38 intersect one another so that the first channel 37 is in fluid communication with the second channel 38. According to an aspect, the second channel 38 includes a primary distribution channel 38a and a secondary distribution channel 38b. Each distribution channel 38a, 38b intersects the other in a cross-wise direction so that they are fluidly connected to each other. When the channels 36 includes the first channel 37, the primary distribution channel 38a and the secondary distribution channel 38b, each of the channels 37, 38a, 38b intersect one another so that the first channel 37 is in fluid communication with the primary and secondary distribution channels 38a, 38b.
The non-mass explosive body 30 is composed of an electrically conductive, electrically dissipative or electrostatic discharge (ESD) safe synthetic material. According to an aspect, the non-mass-explosive body 30 includes a metal, such as cast-iron, zinc, machinable steel or aluminum. Alternatively, the non-mass-explosive body 30 may be formed from a plastic material. While the non-mass-explosive body 30 may be made using various processes, the selected process utilized for making the non-mass-explosive body 30 is based, at least in part, by the type of material from which it is made. For instance, when the non-mass-explosive body 30 is made from a plastic material, the selected process may include an injection molding process. When the non-mass-explosive body 30 is made from a metallic material, the non-mass-explosive body 30 may be formed using any conventional CNC machining or metal casting processes.
According to an aspect, the detonator 10 includes a cylindrical plug 50. The plug 50 is configured for being at least partially disposed in the hollow interior 26 of shell, adjacent the open end 24, as illustrated in
The detonator 10 further includes a printed circuit board (PCB) 40. The PCB 40 may have a generally cylindrical shape, and may be disposed in a slot formed by the leg portion 34 of the non-mass explosive body 30. A first end 41a of the PCB 40 may be coupled or otherwise secured to the first portion 52 of the plug 50 using any known fastening mechanism. A second end 41b of the PCB houses a plurality of components. Such components may include a plurality of contact/relay contacts. As illustrated in, for instance,
According to an aspect, leg wires 60 extend through the plug 50. The leg wires 60 are configured to provide electrical connection to the PCB 40. According to an aspect, the leg wires include a first leg wire 62, and a second leg wire 64 spaced apart from the first leg wire 62. The first leg wire 62 is electrically coupled to the first contact 44a, while the second leg wire 64 is electrically coupled to the second contact 44b (see, for example,
When the detonator 10 is in use, it is typically axially aligned with an end of a detonating cord (not shown). According to an aspect, upon receiving a sufficient current from the leg wires 62, 64 (and directly from the contacts 44a, 44b), the resistor 42 explodes to generate a high-energy plasma cloud. In the event that the perforating gun in which the detonator 10 is assembled is not flooded, the high-energy plasma cloud travels initiates the primary explosive 31 (and when included, the secondary explosive 33) embedded within the head portion 32 of the detonator 10. The initiation of the primary explosive 31 results in the initiation of the main explosive load 28 housed in the hollow interior 26 of the shell 20. Initiation of the main explosive load 28 may further initiate the axially-aligned detonating cord (not shown) adjacent the closed end 22 of the shell 20. In the event that a fluid has leaked into or flooded the perforating gun system, the channels of the non-mass explosive body 30 facilitate entry of the fluid into the non-mass explosive body 30 to create a barrier between the resistor 42 and the primary explosive 31, which prevents initiation of the main explosive load 28 and disables the detonator 10.
Further embodiments of the disclosure are associated with a detonator/fluid-disabled 110, as illustrated in
A non-mass explosive body 130 is disposed in the hollow interior 126, adjacent the main explosive load 128. The non-mass explosive body 130 may be arranged within the hollow interior 126 of the shell 120, at a location between the open end 124 and the main explosive load 128. According to an aspect, the non-mass explosive body 130 includes an electrically conductive, electrically dissipative or electrostatic discharge (ESD) safe synthetic material. The non-mass explosive body 130 may be composed of a metal (or metal alloy) such as cast-iron, zinc, machinable aluminum or steel. Alternatively, the non-mass explosive body 130 may be composed of a plastic material.
The non-mass explosive body 130 may be substantially cylindrical. According to an aspect, the non-mass explosive body 130 includes a head portion 132, and a leg portion 134 opposite the head portion 132. The head portion 132 is disposed adjacent the main explosive load 128. A primary explosive 131 is embedded within the head portion 132, so that the non-mass-explosive body 130 protects the primary explosive 131 from being unintentionally initiated. According to an aspect, a secondary explosive 133 is adjacent the primary explosive 131. The secondary explosive 133 is configured to seal the primary explosive 131 within the head portion 132. The primary and secondary explosives 131, 133, disposed in the head portion 132, may collectively have a total thickness of about 3 mm to about 30 mm. To be sure, the thickness of the primary and secondary explosives 131, 133 may be adjusted based on the needs of the particular application and the types of explosives that are being utilized. In an embodiment, the primary explosive 131 includes at least one of lead azide, silver azide, lead styphnate, tetracene, nitrocellulose and BAX. The selected secondary explosive 133 may include a material that is less sensitive than the primary explosive 131. In an embodiment, the secondary explosive 133 includes at least one of PETN, RDX, HMX, HNX and PYX.
According to an aspect and as illustrated in
The detonator 110 further includes a cylindrical plug 150. The cylindrical plug 150 is secured in the hollow interior 126 of the shell 120, adjacent the non-mass explosive body 130 (
The plug 150 includes a first portion 152, and a second portion 154. According to an aspect, the plug 150 includes a recessed area 156 that extends around the circumference of the plug 150 between the first and second portions 152, 154. The first portion 152 may include a first outer diameter OD1, and the second portion 154 may include a second outer diameter OD2. The first and second outer diameters OD1, OD2 may be substantially the same, with the recessed area 156 between them. In an embodiment, the first outer diameter OD1 may be less than the second outer diameter OD2. According to an aspect, the first outer diameter OD1 of the first portion 152 may be substantially the same as an inner diameter ID of the shell 120. The first portion 152 is disposed within the chamber 126 of the shell 120 and may be secured therein by virtue of a compression fit or by crimping a portion of the shell onto the first portion 152. The recessed area 156 may help to facilitate the crimping, or otherwise securing, of the shell 120 onto the plug 150.
According to an aspect, an elongated opening 151 extends along a length of the plug 150 (i.e., the longitudinal direction Y of the shell 120. As illustrated in
A printed circuit board/PCB 140 is adjacent the first portion 152 of the plug 150. According to an aspect, the printed circuit board 140 is mechanically coupled to the first portion 152 of the plug 150. The PCB 140 may be secured to the plug 150 by any conventional mechanism, such as, adhesives, and also by friction as the leg wires 160 may be held securely in place inside the plug 150 as soon as the shell 120 is mechanically crimped onto the plug 150 or plug 50. For purposes of convenience, and not limitation, the general characteristics of the PCB 40, though applicable to the PCB 140, are described above with respect to the
The PCB 140 includes one or more components, such as contacts/relay contacts. According to an aspect and as illustrated in
The detonator 110 may include a plurality of leg wires 160 extending through the plug 150. The leg wires 160 provide electrical connection to the PCB 140. The leg wires 160 may include a first leg wire 162 and a second leg wire 164. The first and second leg wires 162, 164 may each be secured in longitudinal slots/channels 153 that extend through the plug 150. The longitudinal slots 153 may extend in the same general direction as the elongated openings 151. The first leg wire 162 is electrically coupled to the first contact 144a, and the second leg wire 164 is electrically coupled to the second contact 144b, to provide electrical connection to the printed circuit board 140.
In use, the detonator 110 functions similar to the detonator 10 described hereinabove with reference to
Embodiments of the present disclosure are further associated with a method 200 of using a detonator 10/110, such as a fluid-disabled detonator, that is associated with a perforating gun system in a wellbore. The detonator 10/110, which is positioned 220 within the perforating gun system, may be configured substantially as described hereinabove. Thus, for purposes of convenience and not limitation, the various features and arrangement of the detonator 10/110 described hereinabove and illustrated in
The detonator 10/110 includes a shell 20/120 having a closed end, an open end, and a hollow area extending between the closed and open ends. A non-mass explosive body is disposed within the hollow area. The non-mass explosive body includes one or more channels that are in fluid communication with the wellbore. According to an aspect, a main explosive load is disposed within the hollow area between the closed end of the shell and the non-mass explosive body. A cylindrical plug 50/150 is positioned at the open end of the shell and is at least partially disposed in the hollow area. A printed circuit board including a resistor, is arranged adjacent the plug and is disposed within the hollow interior.
The method 200 further includes lowering 240 the perforating gun system into the wellbore and initiating 260 the detonator to trigger an explosive reaction. The detonator 10/110 may be initiated 260 by transmitting 262 a voltage or current through first and second leg wires of the detonator 10/110 to the resistor. The voltage may exceed a threshold voltage, which is required to burst the resistor so the resistor generates a high-energy plasma cloud for initiating the primary explosive, and thus initiating the main explosive load and detonating cord.
According to an aspect, in the event that a fluid has leaked into or flooded the perforating gun system, the channels of the non-mass explosive body, in combination with either the openings 21 of the shell 20 (i.e., of the detonator 10 illustrated in
The present disclosure, in various embodiments, configurations and aspects, includes components, methods, processes, systems and/or apparatus substantially developed as depicted and described herein, including various embodiments, sub-combinations, and subsets thereof. Those of skill in the art will understand how to make and use the present disclosure after understanding the present disclosure. The present disclosure, in various embodiments, configurations and aspects, includes providing devices and processes in the absence of items not depicted and/or described herein or in various embodiments, configurations, or aspects hereof, including in the absence of such items as may have been used in previous devices or processes, e.g., for improving performance, achieving ease and/or reducing cost of implementation.
The phrases “at least one”, “one or more”, and “and/or” are open-ended expressions that are both conjunctive and disjunctive in operation. For example, each of the expressions “at least one of A, B and C”, “at least one of A, B, or C”, “one or more of A, B, and C”, “one or more of A, B, or C” and “A, B, and/or C” means A alone, B alone, C alone, A and B together, A and C together, B and C together, or A, B and C together.
In this specification and the claims that follow, reference will be made to a number of terms that have the following meanings. The terms “a” (or “an”) and “the” refer to one or more of that entity, thereby including plural referents unless the context clearly dictates otherwise. As such, the terms “a” (or “an”), “one or more” and “at least one” can be used interchangeably herein. Furthermore, references to “one embodiment”, “some embodiments”, “an embodiment” and the like are not intended to be interpreted as excluding the existence of additional embodiments that also incorporate the recited features. Approximating language, as used herein throughout the specification and claims, may be applied to modify any quantitative representation that could permissibly vary without resulting in a change in the basic function to which it is related. Accordingly, a value modified by a term such as “about” is not to be limited to the precise value specified. In some instances, the approximating language may correspond to the precision of an instrument for measuring the value. Terms such as “first,” “second,” “upper,” “lower” etc. are used to identify one element from another, and unless otherwise specified are not meant to refer to a particular order or number of elements.
As used herein, the terms “may” and “may be” indicate a possibility of an occurrence within a set of circumstances; a possession of a specified property, characteristic or function; and/or qualify another verb by expressing one or more of an ability, capability, or possibility associated with the qualified verb. Accordingly, usage of “may” and “may be” indicates that a modified term is apparently appropriate, capable, or suitable for an indicated capacity, function, or usage, while taking into account that in some circumstances the modified term may sometimes not be appropriate, capable, or suitable. For example, in some circumstances an event or capacity can be expected, while in other circumstances the event or capacity cannot occur—this distinction is captured by the terms “may” and “may be.”
As used in the claims, the word “comprises” and its grammatical variants logically also subtend and include phrases of varying and differing extent such as for example, but not limited thereto, “consisting essentially of” and “consisting of.” Where necessary, ranges have been supplied, and those ranges are inclusive of all sub-ranges therebetween. It is to be expected that variations in these ranges will suggest themselves to a practitioner having ordinary skill in the art and, where not already dedicated to the public, the appended claims should cover those variations.
The terms “determine”, “calculate” and “compute,” and variations thereof, as used herein, are used interchangeably and include any type of methodology, process, mathematical operation or technique.
The foregoing discussion of the present disclosure has been presented for purposes of illustration and description. The foregoing is not intended to limit the present disclosure to the form or forms disclosed herein. In the foregoing Detailed Description for example, various features of the present disclosure are grouped together in one or more embodiments, configurations, or aspects for the purpose of streamlining the disclosure. The features of the embodiments, configurations, or aspects of the present disclosure may be combined in alternate embodiments, configurations, or aspects other than those discussed above. This method of disclosure is not to be interpreted as reflecting an intention that the present disclosure requires more features than are expressly recited in each claim. Rather, as the following claims reflect, the claimed features lie in less than all features of a single foregoing disclosed embodiment, configuration, or aspect. Thus, the following claims are hereby incorporated into this Detailed Description, with each claim standing on its own as a separate embodiment of the present disclosure.
Advances in science and technology may make equivalents and substitutions possible that are not now contemplated by reason of the imprecision of language; these variations should be covered by the appended claims. This written description uses examples to disclose the method, machine and computer-readable medium, including the best mode, and also to enable any person of ordinary skill in the art to practice these, including making and using any devices or systems and performing any incorporated methods. The patentable scope thereof is defined by the claims, and may include other examples that occur to those of ordinary skill in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal language of the claims.
This application claims the benefit of U.S. Provisional Application No. 62/647,103 filed Mar. 23, 2018, which is incorporated herein by reference in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| 62647103 | Mar 2018 | US |
