The following disclosure generally relates to methods and systems for setting a plurality of explosive devices located remotely down-hole beneath the earth's surface using a networked switching system, and controlling the detonation of the plurality of explosive devices using network addresses corresponding to the explosive devices.
Hydraulic fracturing, also known as “fracking,” is a process for drilling beneath the earth's surface to extract natural gas from shale rock. Once the rock formation is reached, a combination of water, sand and chemicals are inserted into the well to fracture the rock and release gas.
The first step for fracking is to drill and case a well A hole is drilled down vertically and then surface casing is inserted into the hole. Cement is pumped through the casing to seal off the wellbore from fresh water in the earth. After further vertical drilling is completed, a down hole drilling motor is inserted to begin horizontal drilling. When a target distance is reached, production casing is inserted into the full length of the wellbore, and cement is pumped down the casing and out through the hole. Once this step is completed, the hole has been dug and the casing prevents hydrocarbons from seeping out as they are brought to the surface.
The next step is to “perf and frack” the area. “Perfing” is accomplished via a “perforating gun,” which is lowered into the casing. Typically, a plurality of perforating guns, along with corresponding switch subs, are connected to form a gun train. The switch subs include an electronic switch that sends a signal to detonate the corresponding gun. The perf gun is loaded with extremely high explosives. The gun train is lowered by a wireline into the casing, and an electrical current is sent down the hole to set off the explosives in the perf gun. The explosives shoot small holes into the casing and cement. The perf gun explosives can develop a blast pressure on the order of 10 million PSI. The extreme pressures are necessary to overcome both the hydrostatic pressure and the yield pressure of the steel pipe of the perf gun.
After the explosions, the gun train is then pulled from the well. The small holes created by the perf guns provide perforations for the “fracking” stage, which occurs after the gun train is removed.
Finally, the well is “fracked” by sending water, sand and lube into the wellbore under high pressure. The holes in the walls of the well that were blown by the perf gun create channels for this “fracking fluid” to reach the surrounding shale. The extreme pressure causes the shale to fracture, creating a path that allows released gas to flow to the wellbore. Once fracking is complete, a permanent wellhead is installed and a pipeline is constructed to transport the gas.
Exemplary embodiments of the disclosure are directed to a method and system for defining addresses for a networked switching system, controlling and enabling user control over the detonation of a plurality of explosive devices, and setting a plurality of charges located remotely down-hole beneath the earth's surface.
For example, an exemplary embodiment of the disclosure is directed to an addressable switch system that includes a plurality of perforating gun assemblies that are lowered into a wellbore. Each of the plurality of perforating gun assemblies includes a switch sub comprising a network communications module with a unique network address for communications over a network bus, and a perforating gun comprising explosives. The addressable switch system also includes a control panel for at least one of monitoring and controlling the plurality of perforating gun assemblies and a top sub controller that is also lowered into the wellbore. The top sub controller has a first communications module to communicate with the control panel via a wireline and a second communications module to communicate with the plurality of perforating gun assemblies via the network bus. The control panel includes an interface to select one perforating gun assembly from the plurality of perforating gun assemblies based on the unique network address of the switch sub corresponding to the selected perforating gun assembly. The control panel interface can also provide a command signal that at least one of arms and fires the perforating gun corresponding to selected perforating gun assembly.
Another exemplary embodiment is directed to a method for operating an addressable switch system. The method includes providing a plurality of perforating gun assemblies, with each of the plurality of perforating gun assemblies comprising a switch sub and a perforating gun. The method further includes providing a top sub controller and a unique network address for communications over a network bus to each of the switch subs in the plurality of perforating gun assemblies. The method further includes installing explosives in each of the perforating guns of the plurality of perforating gun assemblies and monitoring and controlling the plurality of perforating gun assemblies using a control panel. The method also includes communicating between the control panel and the top sub controller via a wireline and communicating between the top sub controller and the plurality of perforating gun assemblies via the network bus. The method further includes selecting one perforating gun assembly from the plurality of perforating gun assemblies based on the unique network address of the switch sub corresponding to the selected perforating gun assembly, and providing a command signal that at least one of arms and fires the perforating gun corresponding to selected perforating gun assembly.
These and other objects, features and characteristics of the present invention will become more apparent to those skilled in the art from a study of the following detailed description in conjunction with the appended drawings, all of which form a part of this specification. In the drawings:
In conventional systems and assemblies for down-hole blasting, such as fracking, the explosives in each “perf” gun are typically actuated by standard mechanical switches. For example, in known assemblies for fracking, mechanical switches select which perf gun in the gun train is being fired and then ultimately control its firing. While this often provides an acceptable solution, there can be problems with reliability. Typically, if a switch fails to activate a perf gun in the train, perhaps due to a short, there is no way for the operators working at ground level to then select other guns in that train for firing. This can result in a plugged well, requiring operators to pull out the malfunctioning equipment and waste valuable time and expense.
In accordance with certain embodiments of the disclosure, the conventional mechanical switching arrangement may be replaced with a networked architecture that enables digital communication between a controller that selects the perf gun to detonate and the switches that fire the charges in the perf gun. An electronic switch in the switch sub can include an application specific integrated circuit (“ASIC”) configured to interpret and respond to certain digital signals, e.g., signals to arm and fire the perf gun associated with the switch sub. The ASIC can be associated with a unique address so as to be separately addressable for initiation by the controller. Furthermore, each of the ASICs in the switch subs can communicate over a networked bus configured for fault tolerant operation, such that, if a short causes a perf gun to malfunction, other perf guns in the train may still maintain communications over the bus.
In an exemplary embodiment, the control panel 10 sends and receives signals via a serial communications protocol, such as an RS232 signaling link 20, to control panel box 30. The signals can be communicated to switch logic 32 via a voltage translator 31. Of course, other communications protocols may be utilized, and depending upon the protocol and the logic configuration, the voltage translator 31 may be unnecessary. In other embodiments, control panel with GUI 10 may be integrated into the control panel box 32, such that the RS232 link 20 may also be unnecessary. In addition, the control panel 10 (or a separate device) can perform logging and reporting functions that capture the time the perforating guns are fires, the depth, the shock data from accelerometers, etc. The reports can be sent to text or spreadsheet files or over a network to other computers.
In an exemplary embodiment, the control panel box 30 is above ground, at the top of the well. The control panel box 30 may be in communication with a top sub controller 50 via a wireline 40. The top sub controller 50 is in the well, and may be hundreds or even thousands of feet below the surface. In an exemplary embodiment, the wireline 40 includes a high voltage wire, which provides the high voltage, e.g., 300 volts, needed by the detonators in each perf gun. Wireline 40 is also capable of providing communications signals over a potentially long distance, e.g., from control panel box 30 to top sub controller 50. That is, both the communication signals and the high voltage is delivered to the top sub controller 50 using the same wire. In some embodiments, the high voltage is oscillated 8 to 12 volts, e.g., the 300 volt bus may oscillate from 288 volts to 312 volts, such that the top sub controller 50 “interprets” 288 volts as a digital “0” and 312 volts as a digital “1.” Of course, other ranges such as, e.g., 270 volts to 300 volts can also be used.
In an exemplary embodiment, the wireline 40 is fed to voltage translator 51 in top sub controller 50. The voltage translator 51 converts the signal on wireline 40 to a low power signal to power and communicate with a field programmable gate array (FPGA) 52. The FPGA 52 is thus configured to bi-directionally communicate with switch logic 32. The signals communicated via switch logic 32 to FPGA 52 are then translated via Bus Driver 54 into signals that can be communicated over communication bus 56. Bus 56 is a low power communication line that, in some embodiments, can be up to approximately 40 m in length.
Bus 56 sends digital communication signals to the reusable detonator electronics 60-63 in each switch sub. In an exemplary embodiment, there may be up to 24 devices connected to the bus 56. The detonator electronics 60-63 can be individually addressed via switch logic 32 and signaled to, e.g., “ARM” or “FIRE.” In some embodiments, the detonator electronics 60-63 can also receive signals to “DISARM.” Upon receiving a “FIRE” signal, the detonator electronics switches 60-63 send power via the 300V power line 55 to their respective detonators, which then ignite the explosives in each perf gun. As shown in
In an exemplary embodiment, each of the reusable detonator electronics 60-63 may be structurally the same. The electronics 60-63 may include an ASIC including a bus interface (see, e.g., 511, 512 in
In the exemplary embodiment, when the user selects a command for a perf gun (e.g., Gun 1—FIRE), the client computer running the GUI 200, e.g., control panel 10, sends a signal, via, e.g., an RS232 link 20, to control panel box 30, which in turn, will receive and interpret the signals from the control panel 10. For example, if Gun 1 is selected to fire, the control panel box 30 will interpret this command and determine the proper network address of the reusable electronics for Gun 1, and then send a signal with the Gun 1 fire command to top sub controller 50 via wireline 40 using the appropriate protocol. Top sub controller 50 receives and interprets the signal from control panel box 30 and relays the information, e.g., the command to file Gun 1, to the appropriate reusable electronics 60-63 corresponding to Gun 1 via communications bus 56. The reusable electronics 60-63 that corresponds to the selected Gun 1, receives and interprets the signal from bus 56. Because the signal from top sub controller 50 includes the network address of the reusable electronics for Gun 1, the reusable electronics 60-63 of the other perf guns “ignore” the signal from controller 50. Once the reusable electronics of Gun 1, which is already in an “armed” state, detects the fire signal based on the corresponding digital address, the reusable electronics of the Gun 1 will convert the status of Gun 1 from “ARMED” to “FIRE.”
In a fracking well, the casing in the horizontal section of the well can be quite narrow. Accordingly, the perf gun assembly is commonly configured as a narrow cylindrical tube that can be pushed and pulled along within the casing.
In the exemplary addressable switching system, switch sub 430 includes glass sealed connectors 431 and 432 at each end. These connectors are intended to protect the switch electronics 433 from heat, chemicals, gases, and other elements that are known to create a difficult environment for electronic components. In an exemplary embodiment, as seen in
In some embodiments, the glass-metal assembly and/or the switch sub 430 can be filled or coated with a thermal management material to protect the electronics in the addressable system, e.g., the ASIC and reusable electronics 60-63, from high temperatures that could damage the electronics. The thermal management material has a sharp melting point and excellent heat resistance such that the thermal management material can be used around the electronics to increase the inherent thermal lag in the switch sub 430. This means that the switch sub 430 can be exposed to temperatures beyond the limits of the electronics for an extended length of time. This is because, when the thermal management material reaches it melting point, it takes a large amount of additional heat to increase the temperature in switch sub 430 beyond the melting temperature of the thermal management material. In some exemplary embodiments, the thermal management material is a polymer or wax, e.g., a polyethylene. An example of such a material is Polywax 3000 by Baker Hughes, Inc.
As discussed above, the various sections of the perf gun assembly (300, 400) are attached to each other by threaded connections. A threaded connection, however, makes it difficult to keep the communication bus wire 412 and the high voltage bus wire 411 from tangling as the various sections are twisted together.
The spring-loaded connector 1120 includes a metal casing 1121 with a connector section 1122. The connector section 1122 includes a spring-loaded center conductor 1123 and two spring-loaded concentric ring conductors 1124, 1125. The flush connector 1110 is designed to mate with the spring-loaded connector 1120 such that the connectors 1113-1115 match up with and contact spring-loaded conductors 1123-1125, respectively. The contacts on the spring-loaded conductors 1123-1125, as the name implies have springs or other biasing mechanisms to ensure a positive contact with conductors 1113-1115. The spring-loaded connector 1120 may also have a glass-to-metal seal.
In some embodiments, the ends of each section in the perf gun assembly (i.e., perf gun 410, tandem sub 420, switch sub 430) will have either the flush connector 1110 or the spring-loaded connector 1120 and the corresponding end of the next section in the gun assembly will have the other mating connector 1110, 11120. By using a rotary design having a center conductor and concentric ring conductors, the sections of the perf gun assembly can be threaded together without twisting the wires. As with the metal-to-glass seal assembly 1200 discussed above, the number of conductors in the rotary connector assembly 1110 can vary depending on the application.
Continuing with
In accordance with at least one embodiment, the ASIC in the reusable detonator electronics 60-63 can be preprogrammed with a network address that identifies the ASIC device to other devices on the bus 56, e.g., to sub controller 50, control panel box 30, control panel 10, etc. In some embodiments, the network addresses uniquely identifies each perf gun in the system. When a user builds a gun train, the addresses of each of the ASICs in the tandem subs 420 can be placed into the control system. Software that runs the control panel 10 can be configured to prompt the user via the GUI to enter each address into the control system, such that each perf gun assembly 400 is associated with a network address.
To ensure that the correct addresses are entered, in one embodiment, a tester (not shown) can be provided to confirm that, as the gun train is being assembled, the ASIC in each switch sub 420 is communicating properly and responding appropriately to its address. An “assembly checker” (not shown) can additionally include a USB port for a “memory stick” or some other storage device to store information concerning the order of each perf gun assembly 400 in a gun train, so that the information can then be transmitted to the control panel box 30, control panel 10, or another device as needed. In some embodiments, the information can be transmitted via a wired or wireless network.
In another embodiment, two ASICs can be provided in each switch sub 420. One ASIC controls the “firing” functions of the perf gun assembly 400 and the other ASIC controls a switch that either opens or closes the connection of the communications bus and the high voltage wire to the rest of the perf gun assemblies in the system. With this configuration, the switch logic 32 in the control panel box 30 can poll each of the perf gun assemblies 400 and turn them on/off one at a time to determine the order that they are in. In some embodiments, the poll function can be included in the control panel 10. In this manner, the addressing for the different switch subs 420 can be detected in an automated manner after the gun train is assembled, without requiring user intervention.
The automated addressing configuration is illustrated in
Referring to
If the assembly test has passed, the next perf gun assembly is assembled as discussed above. If not, then in step 655, the switch sub 430 is removed and replaced.
If in step 650, it is determined that all perf gun assemblies have been installed, then in step 660, a setting tool is attached. The user installs a switch sub for the setting tool (the switch sub of the setting tool is different from that of a switch sub for firing a gun), and then a “quick change” assembly is attached to the switch sub of the setting tool in step 665. A quick change assembly connects the top sub to the wire line. In step 670, the detonator for the setting tool is connected. In step 675, the setting tool is connected to the firing head, and lastly in step 680, the plug is connected to the firing head.
Upon selecting the number of switches, if there is an error, it will be indicted in 840. At that point, a red light indicates (in 845) that one or more addresses are not responding, which requires troubleshooting. In addition, the addressable switch software is exited on the PC (e.g., control panel 10), the control box (e.g., control panel box 30) is turned off, and the in-truck box is disarmed.
If no errors are presented, then a switch to be command is selected via the PC (e.g., control panel 10) (see step 850). If STATUS is selected (see
After a command is executed, the system determines whether another command is being indicated in step 890. If all commands are completed, the system is disconnected in step 895.
Finally,
Accordingly, in
It will be appreciated to those skilled in the art that the preceding examples and embodiments are exemplary and not limiting to the scope of the present invention. It is intended that all permutations, enhancements, equivalents, combinations, and improvements thereto that are apparent to those skilled in the art upon a reading of the specification and a study of the drawings are included within the true spirit and scope of the present invention. It is therefore intended that the following appended claims include all such modifications, permutations and equivalents as fall within the true spirit and scope of the present invention.
The present application claims priority to and benefit from U.S. Provisional Patent Application No. 61/840,457 titled “Methods And Systems For Controlling Networked Electronic Switches For Remote Detonation Of Explosive Devices” filed on Jun. 27, 2013, the entire content of which is herein expressly incorporated by reference.
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International Application No. PCT/US2014/044752, International Search Report & Written Opinion, 9 pages, Mar. 10, 2015. |
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20150000509 A1 | Jan 2015 | US |
Number | Date | Country | |
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61840457 | Jun 2013 | US |