Remote power management method and system in a downhole network

A method for remotely managing downhole power consumption in a downhole network system is disclosed. The method comprises the steps of monitoring an activation state for each of a plurality of individually activatable electrically-powered modules in a downhole device and determining an optimal activation state for each module according to system demands. The activation state of each module may be selected from the group consisting of activated or deactivated. The method further comprises the step of transmitting a power state switching instruction from a top-hole processing element to a downhole power-consumption state controller over the downhole network. The method also includes the step of switching the selected electrically-powered modules according to the determined optimal activation states.

BACKGROUND OF THE INVENTION

The present invention relates to power management in electronic devices. More particularly, it relates to remote power management in a downhole device connected to a downhole network.

In downhole operations such as drilling for oil, gas, and water, it is often very desirable to take and record measurements at selected points along a tool string and relay that information to surface equipment. U.S. Pat. No. 6,670,880 to Hall (hereafter referenced as the '880 patent), which is herein incorporated by reference for all that it teaches, discloses a downhole data transmission system which enables one or more downhole devices situated along a tool string to be connected through a downhole network to surface equipment.

One challenge in operating electronic devices in a downhole environment is that of providing them with electrical power. It is often difficult to supply downhole power from the surface of a drilling site, and as a result downhole electronic devices are often powered by special batteries. Batteries have a finite duration of operable utility, and a downhole battery may need to be replaced during drilling operations. In many cases, sensitive electronic equipment is placed in a sealed housing inside of a tool string component in order to protect it from downhole conditions. Under such circumstances, it is inconvenient to remove the sealed portion of the housing to access the equipment installed in the tool string component on a very frequent basis. Also, electronic equipment so housed may be extremely difficult to turn on and off once the tool string is downhole.

In addition to the difficulties in accessing them, another problem arises in the fact that electronic devices on a tool string may be left downhole for considerable amounts of time, thus draining power from the batteries.

Various attempts to maximize power efficiency in electronic apparatus have been made in the drilling industry. U.S. Pat. No. 4,709,234 to Forehand, which is incorporated herein by reference for all that it teaches, discloses a power-conserving apparatus that includes a plurality of independently energizable electrical circuits used in receiving electrical signals from a transducer which senses an environmental condition, in processing the electrical signals, and in storing information related to the detected environmental condition. The apparatus is self-monitoring, and may switch power between the independently energizable electrical circuits.

U.S. Pat. No. 5,960,883 to Tubel, which is incorporated herein by reference for all that it teaches, discloses a method of managing power in a control system in a production well, the control system including a plurality of downhole modules which require power and are addressable. The downhole modules are permanently deployed and are for controlling devices that are operatively associated with them. The method includes the steps of maintaining each module in a dormant, low-power state until activation is required and selectively activating one or more of the modules when activation is required.

U.S. Pat. No. 5,784,004 to Esfahami, which is incorporated herein by reference for all that it teaches, discloses an apparatus with a temperature sensor, a pressure sensor, and a control module. Energy is conserved by sending change-in temperature and change-in pressure data. The control module stores previous measurements, determines a “change-in” calculation, generates transmitter activation signals, and generates a control signal. The control module can go into a sleep mode, and is equipped with a wake-up delay generated by a counter.

U.S. patent application Ser. No. 10/710,638, filed in the name of David Hall on Jul. 27, 2004, and incorporated herein by reference for all that it teaches, discloses that a tool may receive power directly through the tool string; when the source of power is disconnected (e.g. during tripping operations), it may automatically go into a sleep mode powered by a small battery until reawakened by the reinstatement of tool string power.

BRIEF SUMMARY OF THE INVENTION

A method for remotely managing downhole power consumption in a downhole network system is disclosed. The downhole network system is preferably integrated into a downhole tool string. The method comprises the steps of monitoring an activation state for each of a plurality of individually activatable electrically-powered modules in a downhole device and determining an optimal activation state for each module according to system demands. The activation state for each module may be selected from the group consisting of activated or deactivated. The optimal activation state for each module may be the most power-efficient activation state for the evaluated downhole operating conditions. The step of determining an optimal activation state for each electrically-powered module may also comprise the step of evaluating downhole operating conditions of a tool string.

The method further comprises the step of transmitting a power state switching instruction from a top-hole processing element to a downhole power-consumption state controller. The instruction is sent over the downhole network and may be to independently activate or deactivate selected modules not operating in their determined optimal activation states. The method also comprises the step of switching the selected electrically-powered modules according to the determined optimal activation states. The activation state of modules may be switched by providing or cutting off an oscillator signal or a power supply to selected modules. The method may also comprise the additional step of transmitting a completion signal to the top-hole processing element.

A remote power management system for a downhole device in a downhole network comprises a top-hole processing element in communication with a downhole power-consumption state controller. The top-hole processing element may be selected from the group consisting of network servers, network nodes, electronic processors, and integrated circuits. The top-hole processing element may also be in communication with an external network. The downhole network is preferably integrated into a downhole tool string, and may further comprise a data transmission system of inductive couplers in tool string components.

The downhole power-consumption state controller is operably connected to a plurality of individually electrically-powered hardware modules in the downhole device. The downhole device may be a network node, an electronic processor, an integrated circuit, a downhole tool, a sensor, or other functional equipment for a downhole environment. The electrically-powered hardware modules are individually activatable. The downhole power-consumption state controller may be configured to alter a power-consumption state of the downhole device.

In select embodiments, the downhole power-consumption state controller is a downhole packet decoding unit. The downhole power-consumption state controller may also be an integrated circuit or an electronic processor. In preferred embodiments, the downhole power-consumption state controller is continuously active. Each electrically-powered hardware module may further comprise an oscillator signal generator module in communication with the downhole power-consumption state controller. The activation states of the modules may be altered by the downhole power-consumption state controller selectively providing or cutting off power and/or a clock signal.

The following figures, in which like elements are labeled with like numerals, are intended to illustrate certain embodiments of the present invention, and not to limit its scope.

Referring toFIG. 1, the present invention is designed for use in a downhole network20. For the purposes of this invention, a downhole network is defined as a system in which at least two physically separate devices, at least one of the devices being located beneath the surface of the earth, may communicate with each other at a data rate of greater than or equal to 30.0 kilobits per second. In this embodiment, the downhole network20is incorporated into a downhole tool string31in a drilling rig21. The downhole network20comprises a top-hole processing element33in communication with a plurality of downhole devices25such as network nodes incorporated into the downhole tool string31. The top-hole processing element33may comprise a network server. In other embodiments, the top-hole processing element may comprise at least one element of the group consisting of network nodes, electronic processors, and integrated circuits. The top-hole processing element33may also be connected to an external network (not shown) such as a local area network (LAN), a satellite network, the internet, a global positioning system (GPS) network, or the like.

The top-hole processing element33comprises a connection22to the rest of the downhole network20. This connection22may be a wireless data connection, or a physical data connection such as that of a swivel assembly. Data may be transmitted between devices25in the downhole network20through a data transmission path27in the downhole tool string31. A preferred system for transmitting data up and down the tool string31comprises inductive couplers in tool joints and is disclosed in the previously referenced '880 patent to Hall. Alternate data transmission paths29may comprise direct electrical contacts in tool joints such as in the system disclosed in U.S. Pat. No. 6,688,396 to Floerke, et al., which is herein incorporated by reference for all that it teaches. Another data transmission system that may be adapted for use with the present invention is U.S. Pat. No. 6,641,434 to Boyle, et al.; which is also herein incorporated by reference for all that it teaches. In other embodiments optical couplers may be used to transmit data from one downhole component to another.

As in most networks, data may be transmitted between downhole devices25in a downhole network by electronic packets26. Packets26may be transmitted up and down the tool string. The digital information contained in the electronic packets26may be modulated on an analog signal when transmitted between downhole devices25.

The electrically-powered hardware modules35,36,37are individually activatable. In other words, the modules35,36,37do not necessarily depend on the activation status of each other in order to be activated or deactivated individually. The electrically-powered hardware modules35,36,37may be switched to an activated or a deactivated state by enabling or disabling a power signal from a power source. The downhole device25comprises a plurality of possible power-consumption states. These states may be off, dormant, low-power, or fully-on. The power-consumption state of the downhole device25may be determined by the number of electrically-powered hardware modules35,36,37that are currently activated. For example, the off power-consumption state may occur when no power is supplied to any of the electrically-powered hardware modules35,36,37. In another example, the fully-on power-consumption state of the downhole device25may occur when power is being supplied to all of the electrically-powered hardware modules35,36,37.

One significant feature of the present invention is the use of a downhole power-consumption state controller34operably connected to the top-hole processing element33through the data transmission path27of the network and the electrically-powered hardware modules35,36,37of the downhole device. The downhole power-consumption state controller34may comprise any of the group consisting of packet decoder units, integrated circuits, software, and electronic processors. In the preferred embodiment, the downhole power-consumption state controller34is maintained in a continuously active state. The downhole power-consumption state controller34is configured to receive instructions from the top-hole processing element33.

The downhole power-consumption state controller34is configured to selectively alter the power-consumption state of the downhole device25. The downhole power-consumption state controller34may alter the power-consumption state of the downhole device25by selectively switching specific electrically-powered hardware modules35,36,37to activated or deactivated states. The downhole power-consumption state controller34may also comprise at least one switching element38connected between a local power source39and at least one electrically-powered hardware module35,36,37. In this particular embodiment of the invention, the switching element38is a transistor and the local power source39is a downhole battery. With such a configuration, the downhole power-consumption state controller34may provide a HIGH voltage (i.e. a digital ‘1’ signal) to the gates of transistors of electrically-powered hardware modules35,36,37that require power for the current power-consumption state while maintaining a LOW voltage (i.e. a digital ‘0’ signal) at the gates of transistors of electrically-powered hardware modules35,36,37that do not require power for the current power-consumption state. Also in this embodiment, each electrically-powered hardware module35,36,37is connected to a separate local power supply39with a separate switching element38wherein all of the switching elements38are governed by the downhole power-consumption state controller34.

Another significant feature of the present invention is the fact that the downhole power-consumption state controller34is configured to receive instructions from the top-hole processing element33with regard to altering the state of the individual electrically-powered modules35,36,37. For example, in this embodiment of the invention, if the top-hole processing element33were to transmit an instruction to the downhole power-consumption state controller34to switch all of the hardware modules35,36,37to an activated state, the downhole power-consumption state controller34would be configured to electronically enable the power signal to all of the electrically-powered hardware modules35,36,37.

Referring now toFIG. 3, in some embodiments the electrically-powered hardware modules35,36,37may be oscillator-controlled hardware modules. For the purposes of this invention, an oscillator-controlled hardware module is defined as an electrically-powered hardware module that requires input from an oscillator41such as a clock source to execute its specified functions. In such cases, another suitable method of activating or deactivating individual modules35,36,37may be to selectively enable or disable an oscillator signal connected to an individual module35,36,37.

In this embodiment of the invention, each of the hardware modules35,36,37comprises a 2-1 digital multiplexer40. The multiplexers40are configured to output either a signal from the oscillator41or a connection to ground42according to input data from a select line43. The output signal from each multiplexer41is coupled to the oscillator signal input of a hardware module35,36,37. The select line43of each multiplexer40is operably connected to the downhole power-consumption state controller34. In this manner, output from the downhole power-consumption state controller34determines whether or not a specific oscillator-controlled module35,36,37receives input from the oscillator41. Thus, if the top-hole processing element33transmits an instruction through the data transmission path27of the downhole network20to the downhole power-consumption state controller34to alter the power-consumption state of the downhole device25, the downhole power-consumption state controller34is configured to selectively switch individual oscillator-controlled modules35,36,37to achieve the requested power-consumption state.

In other embodiments of the invention, an oscillator signal may be disabled or enabled by a pass transistor or other electronic component.

Referring now toFIG. 4, another embodiment of a remote power management system in a downhole network20in accordance with the present invention is depicted. The top-hole processing element33is in communication with a downhole power-state consumption controller34over a data transmission path27comprised by the downhole network20. The downhole power-state consumption controller may comprise a packet decoder unit46that is operably connected to a plurality of oscillator-controlled hardware modules35,36,37in a downhole device25. Each oscillator-controlled hardware module35,36,37may also be operably connected to an oscillator signal generator module (OSGM)45. The oscillator signal generator modules45may receive input from an oscillator41such as a system clock. When not processing instructions, oscillator-controlled hardware modules35,36,37may be maintained continuously in a dormant state by simply not routing an oscillator signal from the oscillator signal generator modules45to the oscillator-controlled hardware modules35,36,37.

The packet decoder unit46is configured to receive packets26of digital information from the downhole network20. When a packet26is received by the downhole power-state consumption controller34, the downhole packet decoder unit46is adapted to route the instruction along with any necessary parameters to one or more of the oscillator-controlled hardware modules35,36,37to which it corresponds. The packet decoder unit46may determine to which oscillator-controlled hardware module35,36,37the instruction corresponds by decoding information in a certain part of the packet26received, such as a header.

In this embodiment, the downhole packet decoder unit46is also able to send an instruction to the oscillator signal generator module(s)45in communication with the selected oscillator-controlled hardware module(s)35,36,37to begin routing the oscillator signal to the appropriate oscillator-controlled hardware module(s)35,36,37. In some embodiments, the oscillator-controlled hardware module(s)35,36,37may already have a predetermined task to perform and only require activation to perform it. In other embodiments, the downhole packet decoder unit46may route additional instructions and/or necessary parameters to the selected oscillator-controlled hardware module(s)35,36,37. Upon receiving an oscillator signal, an oscillator-controlled hardware module35,36,37becomes activated and may thus begin processing the instruction routed to it from the downhole packet decoder unit46. In some embodiments, the oscillator signal generator module45may route the oscillator signal to its corresponding oscillator-controlled hardware module35,36,37for a predetermined amount of time. In preferred embodiments, when an oscillator-controlled hardware module35,36,37completes all tasks related to the instruction routed to it by the downhole packet decoder unit46it sends a signal to its corresponding oscillator signal generator module45. Upon receiving the signal, the oscillator signal generator module45may discontinue routing the oscillator signal to its corresponding oscillator-controlled hardware module35,36,37and thus deactivate it.

In this manner, the top-hole processing element33may transmit an instruction over the downhole network20to activate or deactivate a specific oscillator-controlled hardware module35,36,37in order to change the power-consumption state of the downhole device25. Logic found in the downhole packet decoder unit46and the oscillator signal generator module45may enable the instruction to be carried out.

Referring now toFIG. 5, a downhole network20may comprise a plurality of downhole devices25comprising systems according to the present invention. In this figure, the downhole devices25all comprise remote power-management systems according to the embodiment ofFIG. 4. Specifically, each downhole device25comprises a downhole power consumption state controller34which in turn comprises a packet decoder unit46operably connected to a plurality of oscillator-controlled hardware modules35,36,37, oscillator signal generator modules45, and a local oscillator41as described more fully in the description ofFIG. 4. Each downhole device25is configured to receive instructions from the top-hole processing element33, and may also communicate with other downhole devices25. In some embodiments, downhole devices25may comprise sufficient intelligence to send power management instructions to other downhole devices25in the network. While all of the downhole devices25inFIG. 5are depicted as incorporating the embodiment of the invention disclosed inFIG. 4, it is also possible to incorporate multiple instances of another embodiment or multiple instances of multiple embodiments of the present invention in a single downhole network20. Downhole devices25in the downhole network20may also comprise modulator/demodulators (modems)47and other local circuitry48not affiliated with remote power management systems of the present invention.

Referring now toFIG. 6, a method60for remotely managing power in a downhole network20is disclosed. The method60comprises the step of monitoring61an activation state for each electrically-powered module35,36,37in a downhole device25.

The activation states may be monitored by a top-hole processing element33in communication with the downhole device25. The downhole device may comprise specific circuitry for reporting the activation state of each of its modules to the top-hole processing element33. In this particular embodiment, the method also comprises the step of evaluating62downhole operating conditions of a downhole device25. The downhole operating conditions of the downhole device25may be received and evaluated by a top-hole processing element33. The downhole operating conditions may be drilling conditions of a downhole tool string31. In some embodiments, the downhole operating conditions may be operating conditions at a specific point on the downhole tool string31. The downhole operating conditions may be system demands. One example of a system demand may be the requirement for a certain electrically-powered module35,36,37to be in an activated state in order to carry out a downhole task.

The method60also preferably comprises the step of analyzing63if the downhole device25is operating in the most appropriate state for the conditions evaluated in step62. The most appropriate operating state for the downhole device25may be the most power-efficient operating state for the downhole operating conditions while meeting system demands. The current operating state of the downhole device25may be determined by the current activation status of individual electrically-powered hardware modules35,36,37in the downhole device25.

If the downhole device25is found to be in the most appropriate operating state for the evaluated conditions, it may continue64in its current operating state for a predetermined amount of time or until some other detected change, such as a change in system demands, triggers the step of analyzing63to be repeated. If the downhole device25is not found to be operating at the most appropriate state for the evaluated conditions and system demands, the optimal activation state for each specific electrically-powered hardware module35,36,37may be determined65, preferably by the top-hole processing element33. The activation state of the electrically-powered hardware modules35,36,37may be selected from the group consisting of power being available to the module35,36,37, power being unavailable to the module35,36,37, an oscillator signal being available to the module35,36,37, and an oscillator signal being unavailable to the module35,36,37. This may further entail the step of determining66which of the electrically-powered hardware modules35,36,37need to be activated or deactivated in order to achieve the desired operating state in the downhole device25.

The method60also comprises the step of transmitting67a power state switching instruction from the top-hole processing element33to a downhole power-consumption state controller34over the downhole network20. The downhole power-consumption state controller34of this method60is consistent with descriptions of the downhole power-consumption state controller34in previous figures. A downhole power-consumption state controller may comprise a packet decoder unit46.

The method further comprises the step of switching68the selected electrically-powered modules35,36,37according to the optimal activation states. Preferably, the switching68is performed by the downhole power-consumption state controller34. In some embodiments, the downhole power-consumption state controller34may selectively switch68individual modules35,36,37by selectively providing or cutting off power to the modules35,36,37. In other embodiments, the downhole power-consumption state controller34may switch68the modules35,36,37by selectively providing or cutting of a clock signal.

The step of switching68the selected modules35,36,37may also comprise the additional steps of receiving69the transmission in the downhole power-consumption state controller34and transmitting70a completion signal to the top-hole processing element33when the selected modules have been switched.

Once the selected modules35,36,37of the downhole device25have been switched68, the downhole device25may continue64in its current state for a predetermined amount of time or until a detected change occurs as previously mentioned.