Patent Application
20140345485
The present disclosure relates generally to wellbore casing perforation operations and, more particularly, to a more robust selective fire switch used in casing perforating guns.
After drilling the various sections of a subterranean wellbore that traverses a hydrocarbon-bearing formation, individual lengths of relatively large diameter metal tubulars are typically secured together to form a casing string that is positioned within the wellbore. This casing string increases the integrity of the wellbore and provides a path for producing fluids extracted from producing intervals in the formation to the surface. Conventionally, the casing string is cemented within the wellbore. To produce fluids into the casing string, hydraulic openings or perforations must be made through the casing string and the cement, and extend a short distance into the surrounding subterranean formation.
Typically, these perforations are created by detonating a series of shaped charges that are disposed within the casing string and are positioned adjacent to the formation. Specifically, one or more perforating guns are loaded with shaped charges that are connected with a detonator via a detonating cord. The perforating guns are then connected within a tool string that is lowered into the cased wellbore at the end of a tubing string, wireline, slickline, coiled tubing or other type of downhole conveyance. Once the perforating guns are properly positioned in the wellbore such that the shaped charges are adjacent the formation to be perforated, the shaped charges are detonated, thereby creating the desired hydraulic openings in to the casing string.
To detonate a particular shaped charge, a voltage is commonly sent to a corresponding selective fire switch that includes a filament wire configured to be burned or otherwise disintegrate upon being subjected to a predetermined amount of voltage. The filament wire also typically supports a plunger used to switch the fire switch into detonation mode. Once the filament wire is burned, the plunger is able to switch positions, thereby placing the fire switch in detonation mode. In traditional selective fire switches, the filament wire is usually supported with a pliable terminal or turret and may be susceptible to tensile stresses and environmental vibrations. Upon experiencing extreme vibrations, for example, especially vibrations stemming from adjacent detonations or explosions, the filament wire can fail or may otherwise be rendered inoperable before its intended operation can be carried out.
The present disclosure relates generally to wellbore casing perforation operations and, more particularly, to a more robust selective fire switch used in casing perforating guns.
In some embodiments, a selective fire switch is disclosed and may include a switch housing, a plunger having a head and a body, the body extending longitudinally from the head and at least partially into an opening defined in the switch housing, a first post and a second post arranged on opposing sides of the switch housing, and a filament wire coupled to and extending between both the first and second posts across the switch housing, the filament wire being in contact with the plunger and thereby securing the plunger in a seated configuration within the switch housing.
In some embodiments, a method of operating a selective fire switch is disclosed. The method may include securing a plunger in a seated configuration within a switch housing with a filament wire that engages the plunger, the filament wire being coupled to and extending between a first post and a second post arranged on opposing sides of the switch housing and extending across the switch housing, applying a voltage across the filament wire, burning the filament wire with the voltage, and moving the plunger from the seated configuration to an extended configuration with respect to the switch housing.
In some embodiments, another selective fire switch is disclosed and may include a switch housing, a plunger extending at least partially into an opening defined in the switch housing, an input stanchion and an output stanchion arranged on a first side of the switch housing, the input and output stanchions being electrically conductive and structurally offset from each other, a post arranged on a second side of the switch housing opposite the first side of the switch housing, and a filament wire having a first portion coupled to the input stanchion and extending to the post across the switch housing, and a second portion extending from the post across the switch housing and to the output stanchion, the filament wire being in contact with the plunger and thereby maintaining the plunger in a seated configuration within the switch housing.
The features of the present disclosure will be readily apparent to those skilled in the art upon a reading of the description of the embodiments that follows.
The following figures are included to illustrate certain aspects of the present disclosure, and should not be viewed as exclusive embodiments. The subject matter disclosed is capable of considerable modifications, alterations, combinations, and equivalents in form and function, as will occur to those skilled in the art and having the benefit of this disclosure.
The present disclosure relates generally to wellbore casing perforation operations and, more particularly, to a more robust selective fire switch used in casing perforating guns.
The present disclosure describes a selective fire switch that has structural stanchions or posts configured to reliably support a filament wire that is to be burned or otherwise disintegrated in the process of setting a detonator. The posts provide additional structural strength to the switch and the filament wire such that the filament wire is able to sustain heavy shock loads and vibrations, such as vibrations that are sustained through detonations of adjacent perforation charges. Moreover, the posts may include lateral extensions that bend over or extend across the switch a short distance in order to decrease the deflection potential of the filament wire, thereby reducing the potential for tensile fatigue in the filament wire before its intended operation can be undertaken.
Referring to
As depicted, a wellbore 122 extends through the various earth strata including a hydrocarbon-bearing formation 104. A casing string 124 is cemented within the wellbore 122 using cement 126. The work string 120 includes various tools such as a plurality of perforating gun assemblies 134 arranged at or near its distal end. When it is desired to perforate the casing string 124 and cement 126 in order to provide fluid communication to the formation 104, the work string 120 is lowered through the casing string 124 until the perforating guns 134 are properly positioned relative to the formation 104. Thereafter, one or more shaped charges within the string of perforating guns are sequentially fired, either in an uphole to downhole or a downhole to uphole direction. Upon detonation, the liners of the shaped charges form jets that create a spaced series of perforations extending outwardly through the casing string 124, the cement 126, and into surrounding portions of the formation 104, thereby allowing fluid communication between the formation 104 and the wellbore 122.
In the illustrated embodiment, the wellbore 122 has an initial, generally vertical portion 128 and a lower, generally deviated or horizontal portion 130. The work string 120 may include a retrievable packer 132 which may be sealingly engaged with the casing string 124 in the vertical portion 128 of the wellbore 122. The perforating guns 134 may have a ported nipple 136 arranged at their upper or proximal end, below which is a time domain firer 138. The time domain firer 138 may be arranged at the upper end of a tandem gun set 140 including first and second guns 142 and 144. In the illustrated embodiment, a plurality of such gun sets 140 are utilized, each including a first gun 142 and a second gun 144.
Positioned between each gun set 140 may be a blank pipe section 146 used to control and optimize the pressure conditions in the wellbore 122 immediately after detonation of the shaped charges. In other embodiments, the blank pipe sections 146 may serve as secondary pressure generators. It should be understood by those skilled in the art that any arrangement of perforating guns may be utilized in conjunction with the present disclosure, including both more and less sections of blank pipe 146 as well as no sections of blank pipe 146, without departing from the scope of the disclosure. It will also be appreciated by those skilled in the art that even though
Referring now to
The switch 200 depicted in
The plunger 206 may have a head 208 and a body 210 (
The switch 200 may further include a filament wire 214 that may extend across at least a portion of the housing 202 and may be supported across the housing 202 by at least a first post 216a and a second post 216b. The filament wire 214, also known as a fuse wire or heater wire, may also be configured to at least partially maintain or otherwise secure the plunger 206 in its seated configuration within the housing 202. In some embodiments, for example, the plunger 206 may define or otherwise include at least one groove 218 configured to receive or engage the filament wire 214. In the embodiment of
The filament wire 214 is shown in
In its seated configuration, as shown in
As illustrated, the exemplary toggle mechanism 220 may include a wiper 222 that may be movable between a first position, as shown in
In order to maintain the wiper 222 in the first position or otherwise in contact with the first contact 224a, the body 210 of the plunger 206 may be extended through the opening 212 such that it engages the wiper 222 and overcomes its spring force until the wiper 222 makes contact with the first contact 224a. In such a configuration, the plunger 206 is in its seated configuration and may be maintained therein with the filament wire 214 biasing against a portion of the head 208, such as the at least one groove 218. In the event the filament wire 214 is severed or otherwise fails, such as is depicted in
The filament wire 214 may be coupled to or otherwise attached to the first and second posts 216a,b which generally serve as stanchions that support the filament wire 214 across the housing 202 and hold the filament wire 214 in a substantially tangential relationship with the head 208 of the plunger 206. As illustrated, the first and second posts 216a,b may be arranged on opposing sides of the housing 202 such that the filament wire 214 generally extends across the top of the housing 202. In some embodiments, the filament wire 214 may be soldered, welded, or brazed to one or both of the first and second posts 216a,b, or otherwise attached thereto using a glue or any chemical adhesive known to those skilled in the art. In other embodiments, the filament wire 214 may be fastened to one or both of the first and second posts 216a,b using one or more mechanical fasteners such as, but not limited to, screws, clamps, wedges, rivets, clips, heat shrink tubing, combinations thereof, and the like. In yet other embodiments, the filament wire 214 may form an integral part of one or both of the first and second posts 216a,b, without departing from the scope of the disclosure.
At their respective bases, the first and second posts 216a,b may be soldered to, mechanically fastened to, or otherwise form an integral part of the circuit board 204. In some embodiments, both the first and second posts 216a,b may be electrically conductive or otherwise made of a material that is able to conduct an electrical current therethrough. In other embodiments, however, one of the first or second posts 216a,b may be non-conductive or otherwise made of an insulative material, without departing from the scope of the disclosure. In the illustrated embodiment, both the first and second posts 216a,b are electrically conductive, as will be described below.
In one or more embodiments, at least one of the first and second posts 216a,b may include or otherwise define a lateral extension that extends or otherwise reaches a short distance across or over the housing 202. In
According to one or more embodiments of the disclosure, the switch 200 may be used to set or otherwise arm an igniter or detonator (not shown) used to detonate a corresponding perforating charge (not shown), such as is used in casing perforating operations briefly described above. With the switch 200 and the plunger 206 in their secured and seated configurations, respectively, as depicted in
A first voltage 227 may be sent to the toggle mechanism 220 via a power line 228. The power line 228 may be communicably or otherwise electrically coupled to a power source (not shown) either arranged adjacent the switch 200 (e.g., downhole) or at a remote location (e.g., via wireline, slickline, e-line, etc.), such as the platform 102 of
With the plunger 206 in its seated configuration, the wiper 222 is held in its first position and therefore in contact with the first contact 224a. Accordingly, the first voltage 227 is conveyed to the first contact 224a which may be configured to convey the first voltage 227 to a first conductor line 230a. In some embodiments, the first conductor line 230a may be communicably or otherwise electrically coupled to the first post 216a, such that the first voltage 227 is conveyed to the first post 216a via the first conductor line 230a. As shown in
With continued reference to
Those skilled in the art will readily recognize the several advantages of the first and second posts 216a,b. For example, the first and second posts 216a,b may reliably secure the filament wire 214 across the top of the housing 202 while holding the plunger 206 in its seated configuration. Moreover, the first and second posts 216a,b provide additional structural strength to the switch 200 and the filament wire 214 such that the filament wire 214 may be able to sustain heavy shock loads and vibrations. The lateral extensions 226a,b of each post 216a,b, respectively, may serve to decrease the length and deflection of the filament wire 214, thereby reducing the potential for tensile fatigue, commonly referred to as “support post fatigue.” As a result, the switch 200 provides a more robust and reliable means of setting a detonator.
Referring to
To activate the detonator, and thereby detonate a corresponding perforating charge, a second voltage 234 may be applied across the power line 228 and conveyed through the wiper 222, the second contact 224b, and the second conductor line 230b which applies the second voltage 234 to the detonator. Similar to the first voltage 227, the second voltage 234 may be a positive or a negative voltage, depending on the perforating application and how many switches 200 are to be activated.
Referring now to
Unlike the switch 200 of
In some embodiments, the filament wire 214 may be soldered, welded, or brazed to one or both of the input and output stanchions 302a,b. In other embodiments, the filament wire 214 may be fastened to one or both of the input and output stanchions 302a,b using one or more mechanical fasteners such as, but not limited to, screws, clamps, wedges, rivets, clips, combinations thereof, and the like. In yet other embodiments, the filament wire 214 may form an integral part of one or both of the input and output stanchions 302a,b. Moreover, one or both of the input and output stanchions 302a,b may include or otherwise define a portion of the first lateral extension 226a. In the illustrated embodiment, each of the input and output stanchions 302a,b are shown as defining corresponding portions of the first lateral extension 226a.
In the illustrated embodiment, the first voltage 227 may be conveyed to the input stanchion 302a via the first conductor line 230a. The input stanchion 302a may apply the first voltage 227 across the filament wire 214 and, more particularly, to a first portion 304a of the filament wire 214 that extends from the input stanchion 302a, across the housing 202, and to the second post 216b. The filament wire 214 may then loop around the second post 216 such that the first voltage 227 is conveyed back to the first post 216a or, more particularly, to the output stanchion 302b via a second portion 304b of the filament wire 214. More particularly, the second portion 304b may be configured to extend from the second post 216b, across the housing 202, and to the output stanchion 302b. The output stanchion 302b may convey the first voltage 227 downstream, such as to ground, for example.
As briefly discussed above, the filament wire 214 may be manufactured or otherwise configured to exhibit a predetermined resistance per unit length, and the first voltage 227 may be a predetermined voltage used to overcome the predetermined resistance of the filament wire 214. As a result, as the first voltage 227 is conducted through the filament wire 214, the filament wire 214 may be configured to burn, disintegrate, or otherwise fail, thereby freeing the plunger 206 to move into its extended configuration, as depicted in
Those skilled in the art will readily appreciate that looping the filament wire 214 around the second post 216 via the first and second portions 304a,b of the filament wire 214 requires the first voltage 227 to traverse a greater effective length of the filament wire 214. Increasing the effective length of the filament wire 214 may increase its resistance such that a reduced amount of voltage would be required to burn or otherwise disintegrate the filament wire 214.
Moreover, looping the filament wire 214 around the second post 216 via the first and second portions 304a,b also offers an increased amount of strength for the filament wire 214 such that the filament wire 214 may be better able to sustain vibrations and other shock loading that may be encountered in a downhole environment.
Referring now to
In
In
Those skilled in the art will readily recognize several other variations that the plunger 206 may assume while remaining within the scope of the present disclosure. The embodiments depicted in
Therefore, the disclosed systems and methods are well adapted to attain the ends and advantages mentioned as well as those that are inherent therein. The particular embodiments disclosed above are illustrative only, as the teachings of the present disclosure may be modified and practiced in different but equivalent manners apparent to those skilled in the art having the benefit of the teachings herein. Furthermore, no limitations are intended to the details of construction or design herein shown, other than as described in the claims below. It is therefore evident that the particular illustrative embodiments disclosed above may be altered, combined, or modified and all such variations are considered within the scope and spirit of the present disclosure. The systems and methods illustratively disclosed herein may suitably be practiced in the absence of any element that is not specifically disclosed herein and/or any optional element disclosed herein. While compositions and methods are described in terms of “comprising,” “containing,” or “including” various components or steps, the compositions and methods can also “consist essentially of” or “consist of” the various components and steps. All numbers and ranges disclosed above may vary by some amount. Whenever a numerical range with a lower limit and an upper limit is disclosed, any number and any included range falling within the range is specifically disclosed. In particular, every range of values (of the form, “from about a to about b,” or, equivalently, “from approximately a to b,” or, equivalently, “from approximately a-b”) disclosed herein is to be understood to set forth every number and range encompassed within the broader range of values. Also, the terms in the claims have their plain, ordinary meaning unless otherwise explicitly and clearly defined by the patentee. Moreover, the indefinite articles “a” or “an,” as used in the claims, are defined herein to mean one or more than one of the element that it introduces. If there is any conflict in the usages of a word or term in this specification and one or more patent or other documents that may be incorporated herein by reference, the definitions that are consistent with this specification should be adopted.
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/US2013/036204 | 4/11/2013 | WO | 00 | 2/6/2014 |
