WO2001053656A1 - Downhole electrical transmission system - Google Patents

Downhole electrical transmission system Download PDF

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Publication number
WO2001053656A1
WO2001053656A1 PCT/US2001/000147 US0100147W WO0153656A1 WO 2001053656 A1 WO2001053656 A1 WO 2001053656A1 US 0100147 W US0100147 W US 0100147W WO 0153656 A1 WO0153656 A1 WO 0153656A1
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WO
WIPO (PCT)
Prior art keywords
conductor
controller
recited
electric power
transmitting
Prior art date
Application number
PCT/US2001/000147
Other languages
French (fr)
Inventor
Steven C. Owens
Original Assignee
Haliburton Energy Services, Inc.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Haliburton Energy Services, Inc. filed Critical Haliburton Energy Services, Inc.
Priority to AU2001227566A priority Critical patent/AU2001227566A1/en
Publication of WO2001053656A1 publication Critical patent/WO2001053656A1/en

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Classifications

    • HELECTRICITY
    • H04ELECTRIC COMMUNICATION TECHNIQUE
    • H04BTRANSMISSION
    • H04B3/00Line transmission systems
    • H04B3/02Details
    • H04B3/44Arrangements for feeding power to a repeater along the transmission line
    • EFIXED CONSTRUCTIONS
    • E21EARTH DRILLING; MINING
    • E21BEARTH DRILLING, e.g. DEEP DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B47/00Survey of boreholes or wells
    • E21B47/12Means for transmitting measuring-signals or control signals from the well to the surface, or from the surface to the well, e.g. for logging while drilling

Definitions

  • the present invention relates generally to the field of tool operation downhole in a wellbore and, in an embodiment described herein, more particularly provides an improved system for providing electric power to downhole instruments and other tools and for transmitting electric signals from such tools to the well surface.
  • Downhole well instruments and other tools are positioned in hydrocarbon producing wells to detect well conditions and to control well operations.
  • fluid pressure communication systems communicate between the well surface and downhole tools positioned at great depths below the well surface, such systems are affected by distortions within the well fluid and by delays in data transmission.
  • the hard wires for communicating electricity to downhole tools are commonly referred to as l-wires.
  • a separate l-wire is connected between well surface equipment and the downhole tool.
  • One type of tool comprises a pressure and temperature transducer, which typically produces one frequency for pressure and one frequency for temperature.
  • a regulated voltage is transmitted through the l-wire from the well surface equipment to the pressure and temperature transducer, and a linear regular converts the voltage to the voltage required by the pressure and temperature transducer.
  • Pressure and temperature signals are transmitted to the well surface with time division multiplexing techniques.
  • the pressure signal from the pressure transducer is transmitted to the well surface by modulating the current in the l-wire.
  • the temperature signal from the temperature transducer is transmitted to the well surface by modulating the current in the l-wire when the pressure transducer is not transmitting.
  • This technique can be used for a single well tool such as the pressure and temperature transducer described.
  • this technique has certain limitations. If another gauge or tool is positioned in the well, an additional l-wire must be installed. This increases the cost and requires the use of multiple l-wires in a wire array. Additionally, the electric signals can only be transmitted in one direction, such as from the downhole tool to the well surface. This limitation on the transmission of signals reduces the flexibility of the system for communication information.
  • a frequency band transmitted data from a pressure and temperature gauge, and a different frequency band transmitted data from the gas lift valve.
  • the current was reversed through the l-wire.
  • the voltage was raised to overcome the current transmission losses caused by the resistivity of the l-wire.
  • a diode was positioned in series with the gauge load to block the reverse line voltage.
  • the system should be able to transmit different types of information and electric signals and should be able to meet different power requirements of downhole tools.
  • the above problem in the art is alleviated by the provision of apparatus for transmitting electric power and signals between a well surface electrical source and a downhole well tool.
  • the apparatus comprises a controller located at the well surface, a receiver module engaged with the well tool for receiving electric power and signals for operating the well tool, a conductor engaged with the electrical source and being connected between the controller and the receiver module for transmitting electrical power and signals between the controller and the receiver module, and a choke engaged between the controller and the conductor for selectively isolating the controller from electric power in the conductor.
  • the apparatus comprises a controller located at the well surface wherein the controller includes a communication transmitter operable to generate an electric signal representing at least two states, a receiver module engaged with the well tool for receiving electric signals and for operating the well tool, a conductor connected between the transmitter and the receiver module, and a regulator engaged with the conductor for modifying the electric power transmitted through the conductor and for transmitting the modified electric power to the well tool.
  • the controller includes a communication transmitter operable to generate an electric signal representing at least two states, a receiver module engaged with the well tool for receiving electric signals and for operating the well tool, a conductor connected between the transmitter and the receiver module, and a regulator engaged with the conductor for modifying the electric power transmitted through the conductor and for transmitting the modified electric power to the well tool.
  • FIG. 1 illustrates the position of an embodiment of the invention relative to a wellbore
  • FIG. 2 illustrates a schematic view of an embodiment of the invention
  • FIG. 3 illustrates a cross-sectional view of an l-wire
  • FIG. 4 illustrates one embodiment of a regulator for converting high voltage low current power to low voltage high current power
  • FIG. 5 illustrates a schematic view showing one embodiment of a communication system having a choke for regulating electricity transmission.
  • FIG. 1 Representatively and schematically illustrated in FIG. 1 is an apparatus which embodies principles of the present invention and is used to transmit electric power and electric signals between a subsurface well tool and the well surface.
  • directional terms such as “above”, “below”, “upper”, “lower”, etc., are used only for convenience in referring to the accompanying drawings. Additionally, it is to be understood that the various embodiments of the present invention described herein may be utilized in various orientations, such as inclined, inverted, horizontal, vertical, etc., and in various configurations, without departing from the principles of the present invention.
  • the apparatus depicted in FIG. 1 is illustrated in well bore 10 and is generally identified as a surface interface unit shown as controller 12, two conductor wire 14, and receiver module or power modem 16 engaged with downhole well tools 18.
  • controller 12 two conductor wire 14
  • receiver module or power modem 16 engaged with downhole well tools 18.
  • tools is defined as including a wide range of sensors, gauges and equipment, including but not limited to temperature sensors, flow meters, pressure transducers, density sensors, packers, sliding sleeves, control valves, injection ports, gas lift valves, and any other instruments or devices in a wellbore.
  • Controller 12 includes general purpose computer 22, modulator/demodulator 24, and mixer 26.
  • Computer 22 can comprise any computer system having a keyboard or other operator interface, a display screen, and a communication port (not shown). Computer 22 generates commands requested by the operator and displays information for review by the operator.
  • Command signals generated on computer 22 by an operator are combined with a modulation signal in mixer 26, the modulation signal is mixed with the high voltage from DC power source 20, and the combined signal is applied to wire 14. In this fashion, wire 14 simultaneously transmits electric power and communication signals.
  • wire 14 is illustrated in one embodiment as an l-wire comprising first conductor 28, insulation 30, and control line or second conductor 32.
  • First conductor 28 is suitable for conducting current from controller 12 through second conductor 32.
  • First conductor 28 can comprise an electricity conducting material such as copper or aluminum.
  • Second conductor 32 can comprise a corrosion resistant material such as lconel and prevents fluids from contacting insulation 30 and first conductor 28.
  • insulation 30 can comprise an insulating material such as Teflon and further prevents first conductor 28 and second conductor 32 from electrical shortcircuits. insulation 30 also maintains a constant spacing between first conductor 28 and second conductor 23 along the entire length of first conductor 28.
  • equal spacing of the conductor is accomplished by maintaining first conductor 28 concentric with the outer tube forming second conductor 32.
  • the uniformity of spacing between first conductor 28 and second conductor 32 is important to the efficient operation of the invention because the length of conductors 28 and 32 is great. If insulation 30 was non-uniform, the distance between first conductor 28 and second conductor 32 would vary over distance and would create an impedance upset. Such upset would reflect a portion of the modulation signal, thereby creating standing waves interfering with communication signals on first conductor 28 and second conductor 32. The interference created by such standing waves is undesirable because such interference can attenuate and distort the communication signals and cause regulator 34 to be unstable.
  • the invention permits signal communication through wire 14 in addition to power transmission.
  • Command signals from computer 22 are combined with a modulation signal in modulator/demodulator 24, are further combined with high DC voltage with mixer 26, and are communicated through first conductor 28.
  • Such signals are transmitted through first combiner 36, are demodulated through modulator/demodulator 38, and are received by embedded processor 40.
  • the same signal or series of signals are received by additional combiners 41 and a different embedded processor (not shown) associated with other well tools 18.
  • embedded processor 40 can do nothing (not addressed), can send data back to controller 12, or can perform a selected control function.
  • first conductor 28 has an impedance greater than zero
  • the maximum power that can be supplied to each power modem 16 is the power from DC source 20 minus the power consumed by the impedance of first conductor 28.
  • Such power loss equals the current squared multiplied by the impedance of first conductor 28.
  • power modem 16 can convert high voltage, low current power in wire 14 to a lower voltage which is desirable because electronic circuits and other electrical devices typically require low supply voltage.
  • Regulator 34 provides this conversion, and permits the operation of tools requiring relatively high current such as motors, solenoids, and other devices.
  • Regulator 34 preferably comprises a regulator that does not function as a linear regulator.
  • a linear regulator is undesirable for such use because the power dissipated in a linear regulator is equal to the difference between the input and output voltages multiplied by the current flowing to the load, assuming fixed output voltages and current. Excessive power dissipation by linear regulators in a well control system would require a large heat sink and would reduce the reliability of the system.
  • FIG. 4 illustrates a schematic of one embodiment for regulator 34.
  • High voltage is present at node 44, and electronic switch 46 is initially closed to cause current to flow into inductor 48. Because of inductance, voltage at load 50 will rise at a controlled rate.
  • Control system 52 monitors the voltage increase in load 50. When voltage in load 50 reaches the desired voltage, switch 46 is opened by control system 52 and stored energy in inductor 48 will flow through load 50 and diode 54.
  • Control system 52 monitors the drop in voltage at load 50 and turns on electronic switch 46 when the voltage falls below the desired voltage. This process is repeated, and power losses during such conversion are limited to the resistance of electronic switch 46, the resistance of inductor 48 and the loss in diode 54.
  • the output current can be greater than the input current. Consequently, downhole tools 18 requiring high current can be powered without the high current losses typically experienced in first conductor 28 at low voltage and high current.
  • the electric power provided by first conductor 28 can be controlled to provide different electric currents and voltages to different tools 18 within the system. Additionally, the current and voltage distributed to each tool can be detected by the respective power modems 16 and transmitted to computer 22. Computer 22 can process this information and can selectively operate tools 18 to reduce or increase the electric power required for each tool 18. In this fashion, the entire production system can be controlled so that the power transmitting capability of wire 14 is not exceeded.
  • This feature of the invention accounts for the power consumption of each tool 18 and reduces the possibility of system failure.
  • Power modem 16 can be configured as a distinct package attachable to wire 14 and engageable to well tool 18. In this fashion, power modem 14 uniquely provides the power and communication link between controller 12 and well tool 18.
  • high voltage DC power source 20 would normally have a very low output impedance and would attenuate communication signals.
  • choke 56 permits the DC voltage to pass while preventing modulation current from entering DC power source 20.
  • choke 56 as used herein can be configured in different ways, the unique function provided by choke 56 permits simultaneous transmission of high voltage potential and signals by the same conductor. Choke 56 can also be provided between the line voltage within conductor 14 and a controller such as computer 22 to prevent high voltage from contacting computer 22 or other system components.
  • one embodiment of downhole power modem 16 can include capacitor 58, transformer 60, capacitor 62, amplifier 64, phase lock loop 66, choke 68, capacitor 70 and regulator 72.
  • Capacitor 58 and the primary coil of transformer 60 combine to form a tuned circuit at the modulation frequency. Secondary voltage of transformer 60 is increased by amplifier 64 and is applied to phase lock loop 66. High DC voltage flows through choke 68 to regulator 72. Since regulator 72 will generate noise, choke 68 acts to isolate such noise from wire 14.
  • Capacitor 70 is charged by DC voltage and is discharged when regulator 72 is switched.
  • Phase lock loop 66 is positioned for demodulating electric signals and is equipped with a quadrature phase detector so that when the modulation signal is present, the quadrature detector is driven low to create a space as described below. In this fashion, a non return to zero (NRZ) signal from computer 22 is replicated in tool 18.
  • NRZ non return to zero
  • a NRZ signal is the output signal typically generated by a central processing unit such as computer 22.
  • the NRZ signal generated by embedded processor 40 can be sent to computer 22 by reversing the process described above.
  • the NRZ signal is combined at "AND" gate 74 with a high frequency tone generated by high frequency generator 76.
  • the NRZ signal from computer 22 has two states identified herein as a "mark” and a "space".
  • the space mark is normally associated with a binary "0” and the mark space is normally associated with a binary "1".
  • the NRZ signal can also be viewed as having a third state identified as "no information”. And three modulation frequencies would normally be required to represent these three states.
  • a significant teaching of the invention is that only one modulation frequency is necessary because two of the states are identical, and the lack or absence of a modulation frequency can signify the third state.
  • the present invention is useful in a well control system wherein a single or multiple well tools are installed downhole in a well.
  • a singled wire to transmit power and to communicate electrical signals, the simplicity and resulting reliability of a well control system can be achieved.
  • a single wire requires less space downhole in a well, and problems associated with multiple seal connections are significantly reduced.
  • each power modem 16 is illustrated as being associated with a single well tool, the present invention contemplates that a single downhole receiver module or power modem 16 could be engaged with multiple tools for receiving data and for transmitting signals to such multiple tools.
  • a single power modem 16 could be engaged with multiple tools for receiving data and for transmitting signals to such multiple tools.
  • a single power modem 16 could be engaged with a pressure transducer (not shown) to identify the well pressure in a discrete zone, and the same power modem 16 could communicate signals and power to operate a sliding sleeve or valve (not shown) for opening or closing access to such well zone.

Abstract

An apparatus for transmitting electricity between downhole well tools and the well surface incorporates a surface controller (12) in combination with a conductor (28) and a downhole receiver module. A choke (56) prevents electricity from the controller from entering a high voltage DC power source, and a downhole regulator (34) converts high voltage, low current power into high current, low voltage power. This feature of the invention permits a single wire to transmit sufficient power to operate multiple downhole well tools. The controller (12) also includes a transmitter and a modulator (24) operable to generate an electric signal representing at least two states, wherein a first state is represented by a signal, and the second state is represented by the absence of a signal. A receiver module receives the electric signals and selectively transmits commands to the associated well tool or to the surfaced controller (12).

Description

DOWNHOLE ELECTRICAL TRANSMISSION SYSTEM
TECHNICAL FIELD
The present invention relates generally to the field of tool operation downhole in a wellbore and, in an embodiment described herein, more particularly provides an improved system for providing electric power to downhole instruments and other tools and for transmitting electric signals from such tools to the well surface.
BACKGROUND
Downhole well instruments and other tools are positioned in hydrocarbon producing wells to detect well conditions and to control well operations. Although fluid pressure communication systems communicate between the well surface and downhole tools positioned at great depths below the well surface, such systems are affected by distortions within the well fluid and by delays in data transmission.
To avoid the problems associated with fluid based communication systems, metallic wire conductors communicate electric power and signals between the well surface and subsurface well equipment. In one example, united States Patent No. 5,236,047 to Pringle et al. (1993) disclosed multiple well tools connected to a surface controller with multiple electric conductors. A separate electric conductor or signal line was connected between each downhole tool and the well surface. In a large installation having numerous downhole tools, the large space required by multiple hard wires and the plurality of wire failure paths restricts the utility of this approach. Various techniques transmit power and signals to downhole well tools. In United States Patent No. 4,010,799 to Kern et al. (1977), power losses were reduced by transmitting low frequency alternating current through the conductors. In United States Patent No. 4,689,620 to Wondrak (1987), electrical signals were transmitted through a two wire line by selectively interrupting current transmission. In United States Patent No. 4,720,996 to Marsden et al. (1988), a control circuit established electrical connection to a power system, and provided power after a selected time delay, in united States Patent No. 4,901,069 to Veneruso (1990), inner and outer coils electromagnetically coupled a downhole tool to a conductor. in United States Patent No. 4,995,058 to Byers et al. (1991) short duration pulses represented by "0" and "1" bit voltage impulses transmitted data between downhole and surface locations. In United States Patent No. 5,236,048 to Skinner et al. (1993), electrical signals were transmitted between circuits through a moveable coil and a stationary coil. In united states Patent No. 5,236,047 to Pringle et al. (1993) multiple electrical lines transmitted power and communication signals between the surface and downhole well equipment. In united States Patent No. 5,515,039 to Delattore (1994), a two wire system applied a voltage above a selected threshold to initiate a data communication system, and applied a voltage below the threshold level to collect tool data. In United States Patent No. 4,415,038 to Smith (1996), power and communication signals were transmitted downhole through a modulated DC loop current. By varying the resistance of a second serial output circuit an analog loop current was varied to permit bi-directional digital transmission. The hard wires for communicating electricity to downhole tools are commonly referred to as l-wires. A separate l-wire is connected between well surface equipment and the downhole tool. One type of tool comprises a pressure and temperature transducer, which typically produces one frequency for pressure and one frequency for temperature. A regulated voltage is transmitted through the l-wire from the well surface equipment to the pressure and temperature transducer, and a linear regular converts the voltage to the voltage required by the pressure and temperature transducer. Pressure and temperature signals are transmitted to the well surface with time division multiplexing techniques. The pressure signal from the pressure transducer is transmitted to the well surface by modulating the current in the l-wire. Similarly, the temperature signal from the temperature transducer is transmitted to the well surface by modulating the current in the l-wire when the pressure transducer is not transmitting.
This technique can be used for a single well tool such as the pressure and temperature transducer described. However, this technique has certain limitations. If another gauge or tool is positioned in the well, an additional l-wire must be installed. This increases the cost and requires the use of multiple l-wires in a wire array. Additionally, the electric signals can only be transmitted in one direction, such as from the downhole tool to the well surface. This limitation on the transmission of signals reduces the flexibility of the system for communication information.
Certain limitations of the technique described above have been reduced in applications combining a pressure and temperature gauge and another tool such as a gas lift valve. In one example, a frequency band transmitted data from a pressure and temperature gauge, and a different frequency band transmitted data from the gas lift valve. To operate the gas lift valve, the current was reversed through the l-wire. To supply the substantially higher electric current required by the gas lift valve, the voltage was raised to overcome the current transmission losses caused by the resistivity of the l-wire. To prevent the high voltage from destroying the gauge, a diode was positioned in series with the gauge load to block the reverse line voltage. Although the concept can permit power and signal transmission on a single l-wire, the number of systems attachable to the l-wire is limited by the bandwidth of the l-wire. Moreover, the concept limits the commands to a single downhole tool at a time, which encumbers the ability to perform multiple simultaneous functions.
Accordingly, a need exists for a system for two-way transmission of signals and electric power between the well surface and downhole well tools. The system should be able to transmit different types of information and electric signals and should be able to meet different power requirements of downhole tools.
SUMMARY In carrying out the principles of the present invention, in accordance with an embodiment thereof, the above problem in the art is alleviated by the provision of apparatus for transmitting electric power and signals between a well surface electrical source and a downhole well tool. The apparatus comprises a controller located at the well surface, a receiver module engaged with the well tool for receiving electric power and signals for operating the well tool, a conductor engaged with the electrical source and being connected between the controller and the receiver module for transmitting electrical power and signals between the controller and the receiver module, and a choke engaged between the controller and the conductor for selectively isolating the controller from electric power in the conductor. in other embodiments of the invention, the apparatus comprises a controller located at the well surface wherein the controller includes a communication transmitter operable to generate an electric signal representing at least two states, a receiver module engaged with the well tool for receiving electric signals and for operating the well tool, a conductor connected between the transmitter and the receiver module, and a regulator engaged with the conductor for modifying the electric power transmitted through the conductor and for transmitting the modified electric power to the well tool.
These and other features, advantages and benefits of the present invention will become apparent to one of ordinary skill in the art upon careful consideration of the detailed description of a representative embodiment of the invention hereinbelow and the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 illustrates the position of an embodiment of the invention relative to a wellbore; FIG. 2 illustrates a schematic view of an embodiment of the invention;
FIG. 3 illustrates a cross-sectional view of an l-wire;
FIG. 4 illustrates one embodiment of a regulator for converting high voltage low current power to low voltage high current power; and
FIG. 5 illustrates a schematic view showing one embodiment of a communication system having a choke for regulating electricity transmission.
DETAILED DESCRIPTION
Representatively and schematically illustrated in FIG. 1 is an apparatus which embodies principles of the present invention and is used to transmit electric power and electric signals between a subsurface well tool and the well surface. In the following description of the apparatus, and other apparatus and methods described herein, directional terms, such as "above", "below", "upper", "lower", etc., are used only for convenience in referring to the accompanying drawings. Additionally, it is to be understood that the various embodiments of the present invention described herein may be utilized in various orientations, such as inclined, inverted, horizontal, vertical, etc., and in various configurations, without departing from the principles of the present invention.
The apparatus depicted in FIG. 1 is illustrated in well bore 10 and is generally identified as a surface interface unit shown as controller 12, two conductor wire 14, and receiver module or power modem 16 engaged with downhole well tools 18. As used herein, the term "tool" is defined as including a wide range of sensors, gauges and equipment, including but not limited to temperature sensors, flow meters, pressure transducers, density sensors, packers, sliding sleeves, control valves, injection ports, gas lift valves, and any other instruments or devices in a wellbore.
Referring to FIG. 2, a communication signal from controller 12 is mixed with high voltage DC power from power source 20. Controller 12 includes general purpose computer 22, modulator/demodulator 24, and mixer 26. Computer 22 can comprise any computer system having a keyboard or other operator interface, a display screen, and a communication port (not shown). Computer 22 generates commands requested by the operator and displays information for review by the operator.
Command signals generated on computer 22 by an operator are combined with a modulation signal in mixer 26, the modulation signal is mixed with the high voltage from DC power source 20, and the combined signal is applied to wire 14. In this fashion, wire 14 simultaneously transmits electric power and communication signals.
Referring to FIG. 3, wire 14 is illustrated in one embodiment as an l-wire comprising first conductor 28, insulation 30, and control line or second conductor 32. First conductor 28 is suitable for conducting current from controller 12 through second conductor 32. First conductor 28 can comprise an electricity conducting material such as copper or aluminum. Second conductor 32 can comprise a corrosion resistant material such as lconel and prevents fluids from contacting insulation 30 and first conductor 28. insulation 30 can comprise an insulating material such as Teflon and further prevents first conductor 28 and second conductor 32 from electrical shortcircuits. insulation 30 also maintains a constant spacing between first conductor 28 and second conductor 23 along the entire length of first conductor 28. In a preferred embodiment of the invention as illustrated, equal spacing of the conductor is accomplished by maintaining first conductor 28 concentric with the outer tube forming second conductor 32. The uniformity of spacing between first conductor 28 and second conductor 32 is important to the efficient operation of the invention because the length of conductors 28 and 32 is great. If insulation 30 was non-uniform, the distance between first conductor 28 and second conductor 32 would vary over distance and would create an impedance upset. Such upset would reflect a portion of the modulation signal, thereby creating standing waves interfering with communication signals on first conductor 28 and second conductor 32. The interference created by such standing waves is undesirable because such interference can attenuate and distort the communication signals and cause regulator 34 to be unstable.
As illustrated by the schematic diagram in FIG. 2, the invention permits signal communication through wire 14 in addition to power transmission. Command signals from computer 22 are combined with a modulation signal in modulator/demodulator 24, are further combined with high DC voltage with mixer 26, and are communicated through first conductor 28. Such signals are transmitted through first combiner 36, are demodulated through modulator/demodulator 38, and are received by embedded processor 40. The same signal or series of signals are received by additional combiners 41 and a different embedded processor (not shown) associated with other well tools 18. Depending on the address and command sent by controller 12 as described below, embedded processor 40 can do nothing (not addressed), can send data back to controller 12, or can perform a selected control function.
Because first conductor 28 has an impedance greater than zero, the maximum power that can be supplied to each power modem 16 is the power from DC source 20 minus the power consumed by the impedance of first conductor 28. Such power loss equals the current squared multiplied by the impedance of first conductor 28. Referring to FIG. 2, power modem 16 can convert high voltage, low current power in wire 14 to a lower voltage which is desirable because electronic circuits and other electrical devices typically require low supply voltage. Regulator 34 provides this conversion, and permits the operation of tools requiring relatively high current such as motors, solenoids, and other devices. Regulator 34 preferably comprises a regulator that does not function as a linear regulator. A linear regulator is undesirable for such use because the power dissipated in a linear regulator is equal to the difference between the input and output voltages multiplied by the current flowing to the load, assuming fixed output voltages and current. Excessive power dissipation by linear regulators in a well control system would require a large heat sink and would reduce the reliability of the system.
FIG. 4 illustrates a schematic of one embodiment for regulator 34. High voltage is present at node 44, and electronic switch 46 is initially closed to cause current to flow into inductor 48. Because of inductance, voltage at load 50 will rise at a controlled rate. Control system 52 monitors the voltage increase in load 50. When voltage in load 50 reaches the desired voltage, switch 46 is opened by control system 52 and stored energy in inductor 48 will flow through load 50 and diode 54. Control system 52 monitors the drop in voltage at load 50 and turns on electronic switch 46 when the voltage falls below the desired voltage. This process is repeated, and power losses during such conversion are limited to the resistance of electronic switch 46, the resistance of inductor 48 and the loss in diode 54. By using this feature of the invention, the output current can be greater than the input current. Consequently, downhole tools 18 requiring high current can be powered without the high current losses typically experienced in first conductor 28 at low voltage and high current. The electric power provided by first conductor 28 can be controlled to provide different electric currents and voltages to different tools 18 within the system. Additionally, the current and voltage distributed to each tool can be detected by the respective power modems 16 and transmitted to computer 22. Computer 22 can process this information and can selectively operate tools 18 to reduce or increase the electric power required for each tool 18. In this fashion, the entire production system can be controlled so that the power transmitting capability of wire 14 is not exceeded. This feature of the invention accounts for the power consumption of each tool 18 and reduces the possibility of system failure.
Referring to FIG. 5, one embodiment of receiver module or power modem 16 is illustrated. Power modem 16 can be configured as a distinct package attachable to wire 14 and engageable to well tool 18. In this fashion, power modem 14 uniquely provides the power and communication link between controller 12 and well tool 18.
As shown in FIG. 5, high voltage DC power source 20 would normally have a very low output impedance and would attenuate communication signals. To accommodate this condition, choke 56 permits the DC voltage to pass while preventing modulation current from entering DC power source 20. Although choke 56 as used herein can be configured in different ways, the unique function provided by choke 56 permits simultaneous transmission of high voltage potential and signals by the same conductor. Choke 56 can also be provided between the line voltage within conductor 14 and a controller such as computer 22 to prevent high voltage from contacting computer 22 or other system components.
As illustrated in FIG. 5, one embodiment of downhole power modem 16 can include capacitor 58, transformer 60, capacitor 62, amplifier 64, phase lock loop 66, choke 68, capacitor 70 and regulator 72. Capacitor 58 and the primary coil of transformer 60 combine to form a tuned circuit at the modulation frequency. Secondary voltage of transformer 60 is increased by amplifier 64 and is applied to phase lock loop 66. High DC voltage flows through choke 68 to regulator 72. Since regulator 72 will generate noise, choke 68 acts to isolate such noise from wire 14. Capacitor 70 is charged by DC voltage and is discharged when regulator 72 is switched.
Phase lock loop 66 is positioned for demodulating electric signals and is equipped with a quadrature phase detector so that when the modulation signal is present, the quadrature detector is driven low to create a space as described below. In this fashion, a non return to zero (NRZ) signal from computer 22 is replicated in tool 18. As is known in the art, a NRZ signal is the output signal typically generated by a central processing unit such as computer 22. Similarly, the NRZ signal generated by embedded processor 40 can be sent to computer 22 by reversing the process described above.
As shown in FIG. 5, the NRZ signal is combined at "AND" gate 74 with a high frequency tone generated by high frequency generator 76. The NRZ signal from computer 22 has two states identified herein as a "mark" and a "space". The space mark is normally associated with a binary "0" and the mark space is normally associated with a binary "1". The NRZ signal can also be viewed as having a third state identified as "no information". And three modulation frequencies would normally be required to represent these three states. A significant teaching of the invention is that only one modulation frequency is necessary because two of the states are identical, and the lack or absence of a modulation frequency can signify the third state.
The present invention is useful in a well control system wherein a single or multiple well tools are installed downhole in a well. By using a singled wire to transmit power and to communicate electrical signals, the simplicity and resulting reliability of a well control system can be achieved. A single wire requires less space downhole in a well, and problems associated with multiple seal connections are significantly reduced. Although each power modem 16 is illustrated as being associated with a single well tool, the present invention contemplates that a single downhole receiver module or power modem 16 could be engaged with multiple tools for receiving data and for transmitting signals to such multiple tools. As one representative example, a single power modem 16 could be engaged with multiple tools for receiving data and for transmitting signals to such multiple tools. As one representative example, a single power modem 16 could be engaged with a pressure transducer (not shown) to identify the well pressure in a discrete zone, and the same power modem 16 could communicate signals and power to operate a sliding sleeve or valve (not shown) for opening or closing access to such well zone.
Of course, a person skilled in the art would, upon a careful consideration of the above description of representative embodiments of the invention, readily appreciate that many modifications, additions, substitutions, deletions, and other changes may be made to the specific embodiments, and such changes are contemplated by the principles of the present invention. Accordingly, the foregoing detailed description is to be clearly understood as being given by way of illustration and example only, the spirit and scope of the present invention being limited solely by the appended claims.

Claims

WHAT IS CLAIMED IS:
1. An apparatus for transmitting electric power and signals between a well surface electrical source and a downhole well tool, comprising: a controller located at the well surface; a receiver module engaged with the well tool for receiving electric power and signals and for operating the well tool; a conductor engaged with the electrical source and being connected between the controller and the receiver module for transmitting electric power and signals between the controller and the receiver module; and a choke engaged between the controller and the conductor for selectively isolating the controller from electric power in the conductor.
2. An apparatus as recited in Claim 1, wherein two or more conductors are connected between the receiver module and the controller for transmitting electric power and signals therebetween.
3. An apparatus as recited in Claim 2 wherein each conductor is equally spaced from the other conductor.
4. An apparatus as recited in Claim 1, wherein the controller includes a communication transmitter and a modulator operable for generating an electric signal representing at least two states and for transmitting the electric signal to the conductor.
5. An apparatus as recited in Claim 1, further comprising a regulator attached to the conductor for modifying the electric power transmitted through the conductor and for transmitting the modified electric power to the well tool.
6. An apparatus as recited in Claim 5, wherein the regulator modifies high voltage, low current electric power into low voltage, high current electric power.
7. An apparatus as recited in Claim 1, wherein the receiver module is engaged with least two tools and selectively generates a signal for operating each well tool.
8. An apparatus as recited in Claim 1, wherein said conductor is connected to at least two receiver modules each engaged with a well tool.
9. An apparatus as recited in Claim 1, wherein said receiver module generates a signal for transmission through the conductor to the controller.
10. An apparatus for transmitting electric power and signals between a power source at the well surface and a downhole tool, comprising: a controller located at the well surface, wherein the controller includes a communication transmitter operable to generate an electrical signal representing at least two states; a receiver module engaged with the well tool for receiving electric signals and for operating the well tool; a conductor connected between the transmitter and the receiver module; and a regulator engaged with the conductor for modifying the electric power transmitted through the conductor and for transmitting the modified electric power to the well tool.
11. An apparatus as recited in Claim 10, wherein the regulator modifies the electrical power from high voltage, low current to low voltage, high current electric power before such electric power is transmitted to the well tool.
12. An apparatus as recited in Claim 10, further comprising a second conductor attached to the controller, and further comprising at least two regulators each attached to the conductors and to a different well tool.
13. An apparatus as recited in Claim 12, wherein each regulator is capable of transmitting an electric signal to the controller.
14. An apparatus as recited in Claim 12, wherein the electric signal transmitted by each regulator identifies the power transmitted to the respective well tool.
15. An apparatus as recited in Claim 10, wherein the controller is capable of receiving electric signals, of processing signals to monitor the total electric power transmitted through the conductors, and of transmitting a signal to the regulator to modify the quantity of electric power transmitted by the regulator to a well tool.
16. An apparatus as recited in Claim 10, further comprising a second conductor between the well tool and the controller for transmitting electrical power and signals therebetween.
17. An apparatus as recited in Claim 10, wherein said receiver module includes a phase lock loop system for demodulating the electric signal.
18. An apparatus as recited in Claim 10, further comprising a modulator engaged with the transmitter for transmitting an electric signal from the transmitter to the conductor, wherein the modulator includes a logical gate for transmitting the electric signal to the conductor.
19. An apparatus as recited in Claim 10, wherein the receiver module includes a transformer and a capacitor combined with the inductance of the transformer to form a resonant circuit at the modulation frequency generated by the modulator and transmitter.
PCT/US2001/000147 2000-01-18 2001-01-03 Downhole electrical transmission system WO2001053656A1 (en)

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US09/484,081 2000-01-18

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2004111389A1 (en) * 2003-06-13 2004-12-23 Shell Internationale Research Maatschappij B.V. System and method for transmitting electric power into a bore
US8842744B2 (en) 2009-10-19 2014-09-23 Badger Explorer Asa System for communicating over a power cable

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5995020A (en) * 1995-10-17 1999-11-30 Pes, Inc. Downhole power and communication system

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5995020A (en) * 1995-10-17 1999-11-30 Pes, Inc. Downhole power and communication system

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2004111389A1 (en) * 2003-06-13 2004-12-23 Shell Internationale Research Maatschappij B.V. System and method for transmitting electric power into a bore
GB2418304A (en) * 2003-06-13 2006-03-22 Shell Int Research System and method for transmitting electric power into a bore
GB2418304B (en) * 2003-06-13 2006-11-08 Shell Int Research System and method for transmitting electric power into a bore hole
AU2004247900B2 (en) * 2003-06-13 2008-01-10 Shell Internationale Research Maatschappij B.V. System and method for transmitting electric power into a bore
AU2004247900B9 (en) * 2003-06-13 2008-06-05 Shell Internationale Research Maatschappij B.V. System and method for transmitting electric power into a bore
US8665110B2 (en) 2003-06-13 2014-03-04 Zeitecs B.V. Transmitting electric power into a bore hole
US8842744B2 (en) 2009-10-19 2014-09-23 Badger Explorer Asa System for communicating over a power cable

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