Patent Application
20220018638
Oil and gas exploration and mining operations often involve the detonation of explosives within an underground formation, for example within a borehole drilled into the formation. Oftentimes, explosives are disposed at the desired point in the borehole and detonated by an initiating charge, e.g., a shaped charge that is itself detonated by an initiator, lowered into the borehole after placement of the main explosives.
The initiator is typically carried by a wireline or similar structure extending from the surface down into the borehole. It is crucial that the placement, speed, and direction of the wireline is accurate, not just for the safety of nearby equipment but also for the safety of personnel involved. A typical initiator and initiator holder used to detonate a main explosive or another explosive downhole tool need to be simple, inexpensive, robust and easy to use. In the event that an initiator and initiator holder may include significant structures other than the initiating charge itself, it is highly advantageous that the initiating charge be provided separately from the remainder of the apparatus and inserted into the apparatus as close in time to insertion of the initiator into the borehole as possible. Under such circumstances, the non-explosive portion of the initiator is sometimes referred to as the initiator holder or the like. Assembly of the electronically activated initiator portion of the initiator into the initiator holder needs, also, to be simple, robust and serve to minimize errors/failures.
Assembly of the electronically activated initiator portion and the initiator holder also typically involves attachment of the electronically activated initiator portion to an electrical cable that conveys an electrical signal or voltage to the electronically activated initiator, resulting in initiation of the electronically activated initiator portion thereof. The electrical cable may be an element of the wireline extending to the surface of the borehole or may simply be the wireline itself. Maintaining a connection between the electrical cable and the initiator is one extremely important function of the initiator holder.
There is a need for a device that can support and connect the initiator, electrical cable and shaped charge during the mining process. This device needs to be simple, inexpensive, robust, easy to use, easy to assemble and minimize errors/failures.
According to an aspect, a holding device is disclosed for use in a detonation system. The holding device may include an initiator holder having a first end, a second end, and a longitudinal internal cavity formed within the initiator holder and extending from the first end to the second end. The internal cavity may be configured for retaining an initiator and an electrical cable. The holding device may also include a plurality of retention fingers extending from the first end of the initiator holder configured for retaining a shaped charge within the holding device.
The internal cavity of the holding device may include a first section having a diameter configured for retaining the electrical cable. The internal cavity may further include a second section having a diameter configured for retaining the initiator. The diameter of the second section may be greater than the diameter of the first section of the internal cavity. The holding device may further include a plurality of longitudinal sections. In one case, the holding device may include a first longitudinal half-section and a second longitudinal half-section. The first half-section may be identical to the second half-section. The first half-section may include tabs and the second half section may include corresponding slots formed for mateable engagement with the tabs of the first half-section.
The initiator holder may include an external surface and the holding device may include a top clip positioned on the external surface of the initiator holder and configured for urging the first half-section and the second half-section radially inward. An internal wall of the internal cavity adjacent the top clip may frictionally retain the electrical cable and thereby prevent any tension from pulling against the sealing plug of the initiator. The top clip may include a protruding lip configured to latch onto the external surface of the initiator holder. The initiator holder may include an external surface and the holding device may include a bottom clip positioned on the external surface adjacent the first end of the initiator holder. The bottom clip may be connected by frictional engagement or by mated engagement with the initiator holder.
The holding device may further include at least four retention fingers. The shaped charge may be aligned longitudinally with the initiator. The electrical cable may be connected to the initiator and configured to convey an electrical activation signal to the initiator. The initiator may be wireless and pressure-sealed. The retention fingers may be shaped for retaining a conical shaped charge or a slotted shaped charge. The shaped charge may be an encapsulated and hydraulically sealed shaped charge. Each of the retention fingers may be spaced apart from each other, thus allowing direct contact between an explosive emulsion in a borehole and the shaped charge. The retention fingers may further include a plurality of receiving grooves on an interior surface of each of the retention fingers. The grooves may be configured to engage one or a plurality of mated grooves on an exterior surface of the shaped charge. The holding device may further include a plurality of apertures within the initiator holder configured to provide passage for borehole fluids. The plurality of apertures may be formed longitudinally within the exterior surface of the initiator holder or as circular channels in the initiator holder. The holding device may be injection molded and may be composed of a thermoplastic material. The thermoplastic material may comprise at least one of polyamide, polypropylene, polyethylene, polymethylene oxide, polytetrafluoroethylene, perfluoro(ethylene-propylene), nylon, polyethylene terephthalate, polyvinylidene fluoride and combinations thereof.
According to an aspect, the present embodiment may be associated with a holding device for a detonation system. The holding device may include an initiator holder configured to receive an initiator. The holding device may further include a shaped charge holder configured to receive a shaped charge. The shaped charge holder can extend from the initiator holder and be aligned with the initiator holder such that the initiator is vertically/longitudinally aligned with a back-wall portion of the shaped charge. Further, the shaped charge holder may include a plurality of fingers configured to retain the shaped charge therebetween.
The holding device may also comprise a first section and a second section of the initiator holder. The first section of the initiator may be configured for retaining the initiator, and the second section of the initiator holder may be configured for retaining an electrical cable. The electrical cable may be configured for providing a firing signal to the initiator. The holding device may further comprise at least one clip slideably positioned on an external surface of the initiator holder. The at least one clip may be configured for securing a first half-section of the initiator holder to a second half-section of the initiator holder.
In one aspect, the holding device may comprise a first clip and a second clip. The first clip may be positioned at the second end of the initiator holder, and the second clip may be positioned at the first end of the initiator holder. Further, the initiator holder may also comprise an internal cavity for receiving the initiator and the electrical cable. The internal cavity may comprise a contoured surface that may frictionally engage the electrical cable.
The initiator holder and the shaped charge holder, as explained above, may be injection molded. The holding device may be configured for use with an explosive emulsion in a borehole. The detonation system holding device can be used in detonating an explosive emulsion in a borehole. By using such detonation system holding device, explosive capacity in a borehole operation can be improved.
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.
In the description that follows, the terms “holder”, “cavity”, “clip”, “fingers”, “grooves”, “apertures” and/or “channels”, and other like terms are to be interpreted and defined generically to mean any and all of such elements without limitation of industry usage. Such terms used with respect to embodiments in the drawings should not be understood to necessarily connote a particular orientation of components during use.
For purposes of illustrating features of the embodiments, several embodiments will now be introduced and referenced throughout the disclosure. Those skilled in the art will recognize that these embodiments are illustrative, not limiting and are provided purely for explanatory purposes. In such embodiments, as illustrated using
With reference to
The point at which electrical cable 106 connects to the initiator 104 is one of the more delicate components of systems of this type and, therefore, this connection is prone to failure. The electrical cable receiving portion 202 shown in
The diameter d1 of the electrical cable receiving portion 202 and the diameter d2 of the initiator receiving section 120 may be modified to accommodate electrical cables and initiators of different sizes. The diameter d1 of the electrical cable receiving portion 202 may be between about 2 mm and about 8 mm. The diameter d2 of the initiator receiving section 120 may be between about 5 mm and 10 mm.
With continuing reference to
In an embodiment, holding device 100 may have no apertures 402 in the external surface of the initiator holder 102 or the apertures 402 may have closed bottoms. In either case, the initiator holder 102 will seal any components contained in the longitudinal internal cavity 108 from exposere to any fluids in the borehole. Since the longitudinal internal cavity 108 includes the initiator receiving section 120 and the electrical cable receiving portion 202, any structural elements contained therein will be sealed from exposure to borehole fluids.
Once in place, each of the top clip 502 and the bottom clip 506 retain the first longitudinal section and the second longitudinal section in engagement with one another by substantially preventing radial movement of the first longitudinal section and the second longitudinal section with respect to each other. The first engagement structures 300a and the second engagement structures 300b also act in concert with the top clip 502 and the bottom clip 506 to keep the first longitudinal section and the second longitudinal section in engagement. In the event that the top clip 502 and the bottom clip 506 are formed from a resilient material, the protruding lip 504 may be engaged and disengaged from the radially extending wall 116 to secure and remove the top clip 502 and the bottom clip 506.
The electrical cable 106 and the initiator 104 may be positioned respectively within the electrical cable receiving portion 202 and the initiator receiving section 104 before the first longitudinal section and the second longitudinal section are engaged, such that the electrical cable 106 and the initiator 104 are secured in their respective positions when the first longitudinal section and the second longitudinal section are engaged. Once the top clip 502 and the bottom clip 506 are in place, the electrical cable 106 is firmly gripped by the internal walls of the electrical cable receiving portion 202 of the longitudinal internal cavity 108 and, if present, the protrusions 202a. Further, the retention fingers 114 extending from the distal end of the initiator holder 102 retain the shaped charge 604 once the top clip 502 and the bottom clip 506 are in place. As discussed previously, the retention fingers 114 may be of a shape and material allowing for removal and placement of the shaped charge 604 subsequent to assembly of the holding device 100, including the top clip 502 and the bottom clip 506.
In various embodiments, the holding device 100 may be injection molded and composed of a thermoplastic material. The thermoplastic material may comprise at least one of a polyamide, polypropylene, polyethylene, polymethylene oxide, polytetrafluoroethylene, perfluoro(ethylene-propylene), nylon, polyethelene teraphthelate, polyvinylidene fluoride and combinations thereof. The primary factors in selecting a thermoplastic material are a melting point above 150° C., sufficient stiffness and low brittleness. Glass fiber additives may also be added to the liquid thermoplastic material prior to molding in order to improve the physical characteristics of the holding device 100, e.g., addition of 10% to 30% glass fiber additive to increase stiffness. The holding device 100 could also be made of any material suitable for use in high temperature mining applications. The detonation system holding device 100 can be used with an explosive emulsion in a borehole. Usage of the holding device 100 described in the above embodiments could result in improved explosive capacity of the detonation system in a borehole operation.
Advantages of using the holding device 100 includes and are not limited to the ones that are subsequently mentioned. Several components of the above described holding device 100 may typically be assembled, at least partly, on site by a user. The holding device 100 could be assembled and disassembled quickly, and the holding device 100 obtained upon assembling may be very sturdy. Structural integrity is provided to the holding device 100 with sliding collars, i.e. the top clip 502 and the bottom clip 506. These clips may be used at both ends of the initiator holder 102. Further, at the proximal end of the initiator holder 102, where the electrical cable 106 enters the longitudinal internal cavity 108, a portion of the electrical cable 106 is gripped by the walls of the electrical cable receiving portion 202 as well as optional protrusions 202a in the wall. The grip of the electrical cable 106, initiator 104 and shaped charge 604 may be greatly strengthened by the sliding collars, i.e., the top clip 502 and the bottom clip 506. The electrical cable 106 could thus be secured without usage of or resulting in knots, kinks, and loops. Such arrangement for securing the electrical cable 106 in the holding device 100 thus works as a strain relieving mechanism.
By using an encapsulated shaped charge and a pressure sealed initiator, sealing of the components in the field is avoided, and more explosive emulsion present in the borehole remains in direct contact with the shaped charge 604. This increases the initiation capability and reliability.
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 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 Patent Application No. 62/792,460 filed Jan. 15, 2019, the entire contents of which are incorporated herein by reference in its entirety.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2019/085528 | 12/17/2019 | WO | 00 |
| Number | Date | Country | |
|---|---|---|---|
| 62792460 | Jan 2019 | US |
