Abstract
Self-selecting switch devices, perforating gun systems including the devices, and methods of using the gun systems are provided herein. A self-selecting switch device includes a microcontroller, a logic circuit, and a first switch. The microcontroller is configured for direct operative connection to a shooting panel and to other self-selecting switch devices, wherein the microcontroller is programmed to detect a presence of other self-selecting switch devices that are operatively connected thereto. The first switch is operative to electrically connect a shooting panel to a detonator. The first switch is under operational control of the microcontroller. The logic circuit is in electrical communication with the microcontroller and the first switch. The logic circuit is configured to selectively direct electrical current to the microcontroller or to the first switch.
Claims
1. A self-selecting switch device comprising: a microcontroller configured for direct operative connection to a shooting panel and to other self-selecting switch devices, wherein the microcontroller is programmed to detect a presence of other self-selecting switch devices that are operatively connected thereto; a first switch operative to electrically connect the shooting panel to a detonator, wherein the first switch is under operational control of the microcontroller; and a logic circuit in electrical communication with the microcontroller and the first switch, wherein the logic circuit is configured to selectively direct electrical current to the microcontroller or to the first switch.
2. The self-selecting switch device of claim 1, wherein the logic circuit is configured to receive positive or negative DC voltage.
3. The self-selecting switch device of claim 2, wherein the logic circuit includes a first diode and a second diode, whereby the first diode is configured to pass current of a first polarity to the microcontroller and the second diode is configured to block current of the first polarity to the detonator.
4. The self-selecting switch device of claim 3, wherein the second diode is configured to pass electrical current to the detonator at a second polarity that is opposite the first polarity.
5. The self-selecting switch device of claim 1, further comprising a second switch located between a ground and the detonator wherein the second switch is operative to shunt the detonator.
6. The self-selecting switch device of claim 1, further comprising a switch controller operatively connected to the microcontroller and to the switches.
7. The self-selecting switch device of claim 6, wherein the switch controller is isolated from direct operative connection to the shooting panel and to other self-selecting switch devices by the microcontroller.
8. The self-selecting switch device of claim 1, further comprising a third switch and/or or fourth switch that are operative to connect and disconnect the self-selecting switch device from other self-selecting switch devices upline or downline thereto in a perforating string.
9. The self-selecting switch device of claim 1, wherein the microcontroller is further programmed to cooperatively determine a most downline self-selecting switch device operatively connected thereto.
10. The self-selecting switch device of claim 9, wherein the microcontroller is further programmed to auto-selectively arm a detonator in the most downline un-fired gun in the string.
11. The self-selecting switch device of claim 10, wherein the device is configured for voltage of the same polarity used to determine which switch device is located within the last un-fired gun to also be applied to the microcontroller to selectively arm the detonator.
12. The self-selecting switch device of claim 11, wherein the device is further configured for an opposite voltage polarity, as compared to the voltage polarity used to determine which switch device is located within the last un-fired gun, to initiate the detonator through function of the logic circuit.
13. A perforating gun system comprising: a shooting panel; a perforating gun string in electrical communication with the shooting panel, wherein the perforating gun string comprises an upline perforating gun and a downline perforating gun in electrical communication with the upline perforating gun; wherein the upline perforating gun comprises a first self-selecting switch device, a first detonator in electrical communication with the first self-selecting switch device, and at least one shaped charge detonatable by the first detonator; a downline perforating gun comprising a second self-selecting switch device operatively connected to the first self-selecting switch device, a second detonator in electrical communication with the second self-selecting switch device, and at least one shaped charge detonatable by the second detonator; wherein the first and second self-selecting switch devices comprise: a microcontroller configured for direct operative connection to a shooting panel and to other self-selecting switch devices, wherein the microcontroller is programmed to detect a presence of other self-selecting switch devices that are operatively connected thereto; a first switch operative to electrically connect the shooting panel to the detonator in electrical communication with the respective self-selecting switch device, wherein the first switch is under operational control of the microcontroller; and a logic circuit in electrical communication with the microcontroller and the first switch, wherein the logic circuit is configured to selectively direct electrical current to the microcontroller or to the first switch.
14. The perforating gun system of claim 13, wherein the shooting panel is configured to selectively supply positive or negative DC voltage to the perforating gun string.
15. The perforating gun system of claim 13, wherein the self-selecting switch device includes diodes whereby a first voltage polarity is used to operate the microcontroller, and a second voltage polarity opposite the first voltage polarity is used to activate the detonator in electrical communication with the respective self-selecting switch device.
16. A method of using a perforating gun system comprising: providing a perforating gun system comprising: a shooting panel; a perforating gun string in electrical communication with the shooting panel, wherein the perforating gun string comprises an upline perforating gun and a downline perforating gun in electrical communication with the upline perforating gun, wherein the upline perforating gun comprises a first self-selecting switch device, a first detonator in electrical communication with the first self-selecting switch device, and at least one shaped charge detonatable by the first detonator; a downline perforating gun comprising a second self-selecting switch device operatively connected to the first self-selecting switch device, a second detonator in electrical communication with the second self-selecting switch device, and at least one shaped charge detonatable by the second detonator; wherein the first and second self-selecting switch devices comprise: a microcontroller configured for direct operative connection to a shooting panel and to other self-selecting switch devices, wherein the microcontroller is programmed to detect a presence of other self-selecting switch devices that are operatively connected thereto; a first switch operative to electrically connect the shooting panel to the detonator in electrical communication with the respective self-selecting switch device, wherein the first switch is under operational control of the microcontroller; and a logic circuit in electrical communication with the microcontroller and the first switch, wherein the logic circuit is configured to selectively direct electrical current to the microcontroller or to the first switch; determining which switch device is located within a last un-fired gun in the perforating string using the microcontrollers of the respective self selecting switch devices; and initiating the detonator in electrical communication with the respective self-selecting switch device based on the determination of the last un-fired gun in the perforating string.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) The various embodiments will hereinafter be described in conjunction with the following drawing figures, wherein like numerals denote like elements, and wherein:
(2) FIG. 1 is a schematic diagram illustrating a hollow-carrier perforating gun within a well.
(3) FIG. 2 is a schematic diagram illustrating a shooting panel electrically connected to a perforating gun string.
(4) FIG. 3 is a schematic diagram of a perforating gun system including a self-selecting switch device.
(5) FIG. 4 is an electrical circuit diagram of the self-selecting switch shown schematically in FIG. 3.
(6) FIG. 5 is a flow chart detailing an embodiment of the logic used by a self-selecting switch to arm a detonator.
(7) FIG. 6 is a flow chart detailing another embodiment of the logic used by a self-selecting switch to arm a detonator.
DETAILED DESCRIPTION
(8) The following detailed description is merely exemplary in nature and is not intended to limit the perforating systems and methods as described herein. Furthermore, there is no intention to be bound by any theory presented in the preceding background or the following detailed description. The description is not in any way meant to limit the scope of any present or subsequent related claims.
(9) As used here, the terms “above” and “below”; “up” and “down”; “upper” and “lower”; “upwardly” and “downwardly”; and other like terms indicating relative positions above or below a given point or element are used in this description to more clearly describe some embodiments. However, when applied to equipment and methods for use in wells that are deviated or horizontal, such terms may refer to a left to right, right to left, or diagonal relationship as appropriate. As used herein, “upline” and “downline” refer to positions of perforating guns along a perforating gun string relative to a shooting panel, with downline positions further away in series from upline positions.
(10) The subject matter described here is a self-selecting switch device, a perforating gun system including at least two perforating guns each having a self-selecting switch device, and methods of using the perforating gun system for, e.g., perforating an oil or natural gas well. As shown schematically in FIG. 4, the self-selecting switch devices 10 include a microcontroller 20 configured for direct operative connection to a shooting panel 12 and to other self-selecting switch devices. A first switch 24 is operative to electrically connect the shooting panel 12 to a detonator 21, wherein the first switch 24 is under operational control of the microcontroller 20 (either directly or through an additional switch controller 30). The microcontroller 20, which may be a programmable logic controller (PLC), is programmed to detect the presence of other active self-selecting switch devices 10 that are operatively connected thereto, along a perforating string, through information provided by the switch devices 10. The “operative connection” may be a physical connection, e.g., through wiring, or may be an informational connection facilitated through wireless communication. The microcontroller 20 of different switch devices 10 may further be programmed to cooperatively determine a most downline self-selecting switch device 10 operatively connected thereto, and may also be programmed to auto-selectively arm a detonator (e.g., by closing switch 24 and opening switch 25) in the most downline un-fired gun in the string using a switch device 10 associated with the last un-fired gun in the string 13. However, it is to be appreciated that in embodiments, such determinations can alternatively be made by an external processor that is separate from and in informational communication with the switch devices. A special feature of perforating gun systems 11 including the switch devices 10 having a microcontroller programmed as described is that mono-cable (wireline or slick line) or wireline cables containing multiple electrical wires (often referred to as “conductors”) can be used. Such capabilities are enabled due to the presence of a logic circuit 19 that is configured to selectively direct electrical current to the microcontroller 20 or to switch 24 that electrically connects the shooting panel 12 to the detonator 21. In particular, the logic circuit 19 can include diodes 22, 23 that are configured to direct current to either the microcontroller 20 or to the switch 24 based on polarity of the current (e.g., positive or negative DC voltage), thereby enabling a single current source to be employed that is capable of operating the microcontroller 20 and that is also capable of providing electrical current to activate the detonator 21. However, it is to be appreciated that alternative transistor configurations can be employed in the logic circuit that enable current to be selectively directed to the microcontroller or to the switches.
(11) FIG. 2 depicts an exemplary perforating gun system 11 including a shooting panel 12 and a perforating gun string 13 in electrical communication with the shooting panel 12. In this embodiment, the shooting panel 12 is connected to the perforating gun string 13 through a wireline cable 16. The perforating gun string 13 includes an upline perforating gun 14 and a downline perforating gun 15 in electrical communication with the upline perforating gun 14. The perforating guns 14, 15 may be electrically connected in series. In embodiments, the shooting panel 12 is configured to selectively supply positive or negative DC voltage to the perforating gun string 13 through the wireline cable 16. In an embodiment and referring momentarily to FIG. 4, the self-selecting switch device 10 includes a logic circuit 19 having diodes 22, 23 with one diode 22 controlling electrical current to the microcontroller 20 and the other diode 23 controlling electrical current to a detonator 21 when switch 24 is closed and switch 25 is open. In operation, a first voltage polarity is used to operate the microcontroller 20 with diode 22 configured to pass electrical current to the microcontroller at the first voltage polarity, and a second opposite polarity is used to activate the detonator 21 with diode 23 configured to pass electrical current to the detonator 21 at the second polarity. In embodiments, through operation of the microcontrollers 20 in the respective switch devices 10, a determination may be made regarding which switch device 10 is located within the last un-fired gun in the perforating string 13. Referring to FIG. 4, the switch device 10 includes a first switch 24, which is operative to arm the detonator 21. Optionally, the switch device 10 further includes a second switch 25 to shunt the detonator 21 to ground when the detonator 21 is not armed, a third switch 26, and/or or fourth switch 27 that are operative to connect and disconnect a given self-selecting switch device 10 from the other self-selecting switch devices 10 immediately upline or downline thereto in the perforating gun string 13, thus enabling further control and selective detonation of specific perforating guns 14, 15 in the perforating gun string 13. However, it is to be appreciated that effective operation of the self-selecting switch device 10 is possible without the second switch 25, the third switch 26, and the fourth switch 27. Determinations regarding which switch device 10 is located within the last un-fired gun in the perforating string 13 may be made exclusively between the switch devices 10 through communication with each other, particularly through communication between microcontrollers 20 of the respective switch devices 10, with the determinations optionally communicated to the shooting panel 12 or other external device (such as a portable computing device). For example, in embodiments, voltage of the first polarity is applied to the microcontroller 20 to determine which switch device 10 is located within the last un-fired gun in the perforating string 13. Alternatively, the determinations can be made with an external processor or circuit that gathers data from the microcontrollers 20 in the respective switch devices 10. The microcontroller 20 of the switch devices 10 may be programmed to assure that the switch device 10 in the last un-fired gun is the only one that can be used to arm its corresponding detonator 21. Alternatively, the switch devices 10 can be controlled by the external processor to effectuate such function. The second, opposite voltage polarity may then be applied from outside of the wellbore (e.g. with the shooting panel) to initiate the detonator through function of the logic circuit 19.
(12) In an embodiment and as shown in FIG. 4, when, for example, negative DC voltage is applied to the self-selecting switch device 10, the diode 22 passes the current and microcontroller 20 is energized while diode 23 effectively blocks current to the detonator 21. To comply with safety regulations, the current used with the first polarity should be no more than the detonator's maximum no-fire current, for example less than 10 mA. As alluded to above, first switch 24, optional second switch 25, optional third switch 26, and optional fourth switch 27 are under operational control of the microcontroller 20. In embodiments, the switches 24, 25, 26, 27 are directly controlled by microcontroller 20. In other embodiments and as shown in FIG. 4, a switch controller 30 is operatively connected to the microcontroller 20 and to the switches 24, 25, 26, 27. In embodiments, the switch controller 30 is isolated from direct operative connection to the shooting panel 12 and to other self-selecting switch devices 10 by the microcontroller 20, i.e., the switch controller 30 is directly electrically connected to the microcontroller 20 and the switches 24, 25, 26, 27 only. In the embodiment of FIG. 4, the microcontroller 20 communicates with the switch controller 30 to open or close the switches 24, 25, 26, 27. Voltage of the same polarity used to determine which switch device 10 is located within the last un-fired gun 14, 15 (e.g., the first polarity) may also be applied to the microcontroller 20 to operate the switch controller 30. The switches can be, for example, Micro-Electro-Mechanical-Systems (MEMS) switches or Switch Electronic Circuits (SEC). The optional third switch 26 can be used to disconnect the immediately downline self-selecting switch device. The optional second switch 25 serves to safely shunt the detonator 21 to ground when it is not armed, wherein the second switch is located between a ground and the detonator 21. The first and second switches 24, 25 may be in direct electrical communication, i.e., part of the same electrical line with no intervening switches or devices and with the second switch 25 downline from the first switch in the direction of the detonator 21. The first switch 24 is used to arm the detonator 21 when closed. The optional fourth switch 27 can disconnect the self-selecting switch device 10 from the immediately upline self-selecting switch device in the event of a misfire.
(13) Flow charts are provided in FIGS. 5 and 6 that detail two logic scenarios that can be programmed to the microcontroller 20. Upon detonation of a perforating gun 14, 15, the self-selecting switch device 10 in the gun 14, 15 may be disabled by the detonation shock. To ensure that the self-selecting switch device 10 is destroyed or disconnected during gun detonation, the switch device 10 or its lead wires can be located adjacent to the detonator 21 or in the proximity of shaped charge(s) 17. As shown in the flow charts in FIGS. 5 and 6, if the switch device 10 is still active, the microcontroller 20 may send a signal indicating its active status (e.g., to the shooting panel 12 or a portable computing device) immediately after waking-up. If the microcontroller 20 detects a signal from an immediately preceding switch device 10, then it may determine that it is not associated with the last un-fired gun 14, 15 of the string 13. If no signal is detected from the immediately downstream switch device, then the microcontroller 20 may determine that it is associated with the last un-fired gun 14, 15 in the string and will arm the detonator 21. More specifically, the microcontroller 20 may command the switch controller 30 to close the first switch 24 and open the second switch 25 to electrically connect the detonator 21 and un-shunt the detonator 21 respectively. Optionally, the microcontroller 20 may further command the switch controller 30 to open the third switch 26 (when present) to disconnect the immediately downstream switch device 10. The operator at the surface may then use a power supply or the shooting panel 12 to send the opposite polarity voltage (e.g., the second polarity) through the wireline cable 16, with diode 23 of the logic circuit 19 passing the current to initiate the detonator 21.
(14) In embodiments, in the event that a gun 14, 15 is to misfire, the misfired gun's self-selecting switch device 10 can be bypassed since it would still be active. As shown in FIG. 5, the microcontroller 20 may allow N attempts (for example 3) to successfully initiate the detonator 21. If the switch device 10 is still functional after the N attempts, then the microcontroller 20 may command the switch controller 30 to open the fourth switch 27 and disconnect itself from the immediately upline switch device 10. This feature can also be used if for any reason it is desired to bypass a particular gun 14, 15. In this case, a gun 14, 15 can be armed (N+1) times without sending the second polarity to fire the detonator 21. Alternatively, as shown in FIG. 6, the self-selecting switch device 10 could disconnect itself from the immediately upline switch device 10 after a single failed attempt to fire. In this scenario, a timer may be started upon arming the detonator 21. If the detonator 21 has not fired after a predetermined period of time, then the microcontroller 20 can command the switch controller 30 to disarm the detonator 21 by opening the first switch 24 and disconnect itself from the immediately upline switch device 10 by opening the fourth switch 27.
(15) While at least one exemplary embodiment has been presented in the foregoing detailed description, it should be appreciated that a vast number of variations exist. It should also be appreciated that the exemplary embodiment or exemplary embodiments are only examples, and are not intended to limit the scope, applicability, or configuration of the present disclosure in any way. Rather, the foregoing detailed description will provide those skilled in the art with a convenient road map for implementing an exemplary embodiment of the present disclosure. It being understood that various changes may be made in the function and arrangement of elements described in an exemplary embodiment without departing from the scope of the present disclosure as set forth in the appended claims.
