US20060232138A1 - Electrical power supply arrangement for a downhole measurement assembly - Google Patents
Electrical power supply arrangement for a downhole measurement assembly Download PDFInfo
- Publication number
- US20060232138A1 US20060232138A1 US10/546,056 US54605605A US2006232138A1 US 20060232138 A1 US20060232138 A1 US 20060232138A1 US 54605605 A US54605605 A US 54605605A US 2006232138 A1 US2006232138 A1 US 2006232138A1
- Authority
- US
- United States
- Prior art keywords
- capacitor
- power supply
- tool
- assembly according
- conductor arrangement
- Prior art date
- Legal status (The legal status 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 status listed.)
- Abandoned
Links
Images
Classifications
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M3/00—Conversion of dc power input into dc power output
- H02M3/02—Conversion of dc power input into dc power output without intermediate conversion into ac
- H02M3/04—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters
- H02M3/06—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using resistors or capacitors, e.g. potential divider
- H02M3/07—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using resistors or capacitors, e.g. potential divider using capacitors charged and discharged alternately by semiconductor devices with control electrode, e.g. charge pumps
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
- G01V11/00—Prospecting or detecting by methods combining techniques covered by two or more of main groups G01V1/00 - G01V9/00
- G01V11/002—Details, e.g. power supply systems for logging instruments, transmitting or recording data, specially adapted for well logging, also if the prospecting method is irrelevant
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
- G01V3/00—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation
- G01V3/18—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation specially adapted for well-logging
- G01V3/26—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation specially adapted for well-logging operating with magnetic or electric fields produced or modified either by the surrounding earth formation or by the detecting device
Definitions
- the present invention relates to downhole measurement assemblies and more particularly to the electrical power supply arrangement for such assemblies.
- the oil and gas industry employs a variety of information gathering downhole tools during exploration and drilling of wells. These tools provide such information as hole inclination and azimuth, temperature, radioactivity, or resistivity. These tools are encased in non-magnetic stainless steel cylindrical pressure cases. By their nature, these tools have a large length to diameter ratio. The number of tools that have been introduced over the years has increased. Each tool is aligned serially down the drill string, and power is connected to each in parallel on a bus, which also allows communication between the tools and the transmission of signals to the surface. Traditionally, the pressure case of each tool is grounded and is the return path for DC current.
- the directional measurement tool was always the one furthest down the hole and part of the directional measurement tool is an array of fluxgate magnetometers situated at the bottom of the tool in a module known as the stack. These magnetometers respond to the earth's magnetic field. Recently, other tools have been placed below the directional package and the power required by such tools results in current flowing in wire which passes the magnetometers and which in turn generates an electromagnetic field which causes errors in the readings produced by the magnetometers.
- the pressure cases of the downhole tools have always been grounded and connected to the system zero volts. This means that if conventional current carrying conductors are replaced in the region of the magnetometers by say a twisted pair or a coaxial cable, but otherwise the electrical arrangements remain unaltered, the current in the two conductors of the twisted pair or coaxial cable will be unbalanced as some current will flow through the parallel path of the pressure cases. In fact, most of the current will flow through the pressure case as it is a much better conductor.
- the present invention provides a downhole measurement assembly comprising a metal casing housing a plurality of tool sections, one of which includes a detector sensitive to a magnetic field, and a DC power supply for said tool sections, the power supply and the tool sections being electrically connected to the casing, characterised in that the power supply is connected to at least one tool section via a switching circuit and a conductor arrangement, the switching circuit comprising a capacitor, a plurality of switches and control means operative to alternately charge the capacitor from the DC supply and discharge the capacitor through said at least one tool section using the conductor arrangement so as to inhibit the generation of an electromagnetic field in the conductor arrangement between the capacitor and the said at least one tool.
- FIG. 1 is a diagrammatic representation of a downhole measurement assembly for explaining the present invention
- FIG. 2 shows a basic circuit diagram for explaining the principle underlying the present invention
- FIG. 3 shows a basic circuit diagram of a modification of the circuit shown in FIG. 2 ;
- FIG. 4 shows a more detailed circuit diagram of the circuit shown in FIG. 3 ;
- FIGS. 5 a and b show a block diagram of a practical circuit of the present invention.
- FIG. 6 shows a more detailed circuit diagram of the circuit shown if FIG. 4 .
- FIG. 1 shows a diagrammatic representation of a downhole measurement assembly 1 which comprises a plurality of individual tools 3 encased in non-magnetic stainless steel cylindrical pressure cases which are represented by the conductor 2 and which are mechanically and electrically connected together and also grounded.
- the tools 3 are supplied with DC power from a power supply 4 one side of which is also grounded.
- a stack 5 which includes an array of fluxgate magnetometers is located towards the bottom of the assembly 1 below the individual tools 3 but in this case other tools represented by the block 7 are shown in a position on the other side of the stack 5 from the power supply 4 .
- This means that current for the other tools 7 has to be carried by conductors past the stack 5 and this in turn results in the generation of electromagnetic fields in the region of the stack 5 which causes in the output from the stack 5 to be inaccurate.
- the present invention proposes to use a twisted pair or coaxial cable for the current carrying conductors but which allows the pressure cases to be electrically connected together in such a manner that they carry no current. This is achieved by utilising a capacitor connected by a switching network as will be explained in relation to FIG. 2 .
- one side of the DC supply 4 is connected to the pressure casing 1 a of the downhole measurement assembly which is in turn grounded.
- a capacitor 20 is connected between the poles of a two-pole electronic changeover switch which in one position of the switch accumulates charge from the supply and, when the switch is changed over to its other position, allows the capacitor to transfer its charge to one or more downhole tools which are represented by the load 24 . It can be seen that although the grounds are connected, no current can flow between them. Thus, all the current delivered to the downhole tools represented by the load 24 must flow in the conductors 25 and 26 connected between the electronic changeover switch 22 and the downhole tools.
- conductors 25 and 26 thus carry the same current but in opposite directions and can be a twisted pair or coaxial cable which can be routed past the magnetometers in the stack without causing electromagnetic interference.
- the changeover switch position is reversed quickly, the effect is enhanced and it is preferred to reverse the switch 22 several thousand times a second.
- FIG. 3 shows an improved arrangement of the circuit shown in FIG. 2 .
- the improved arrangement employs two capacitors 20 a and 20 b each provided with its own two-pole electronic changeover switch 22 a and 22 b respectively. With this arrangement, when one capacitor is charging, the other is discharging. This arrangement is more efficient and reduces the ripple voltage between the conductors. This is an important consideration as the conductor 25 is also used as a communications bus in many downhole tool arrangements.
- FIG. 4 shows a more practical circuit diagram of the circuit shown in FIG. 3 and in FIG. 4 the two-pole changeover switches have been replaced by semiconductor switches in the form of MOSFETs. It is preferred to use P-channel MOSFETs for switches SW 1 to SW 4 and N-channel MOSFETs for switches SW 5 to SW 8 . Although it is not shown in FIG. 4 , an oscillator is provided in order to drive the MOSFET switches.
- the positive pole of the DC power supply 4 to the capacitor 20 a is via MOSFET switch SW 1 when closed and the other side of capacitor 20 a is connected to the negative terminal of the DC power supply 4 via the MOSFET switch SW 5 . In this way, capacitor 20 a charges.
- capacitor 20 b is connected to and discharges into the load via the closed MOSFET switches SW 4 and SW 8 .
- the switches SW 1 , SW 5 , SW 4 , and SW 8 are opened and the switches SW 2 , SW 6 close which allows the capacitor 20 a to discharge through the load while the MOSFET switches SW 3 and SW 7 are also closed to allow the capacitor 20 b to be charged from the power supply 4 .
- FIGS. 5 a and 5 b when combined at conductors A-J show a block diagram of a practical circuit diagram for implementing the arrangement shown in FIG. 4 .
- the same component numbers and designations are used in FIGS. 5 a and 5 b as are used in FIG. 4 and consequently a detailed description of the operation of FIG. 5 will not be given.
- the oscillator is now shown and represented by the reference numeral 50 .
- the reference numeral 50 In the present example, it operates at about 53 KHz and controls the MOSFETs SW 1 to SW 8 .
- the frequency is not particularly critical but operation has been found to be optimal with a frequency in the region 50 KHz to 65 KHz.
- the current taken by it is approximately 16 mA. This is due to the current required by the oscillator and amplifier and the current required to switch the MOSFETs, some of which have a gate capacitance of up to 1.5 nF. When it is merely required to pass current past the stack without the need for preventing magnetic interference, current can be saved by turning off the oscillator, in which case the upper and lower switches are short circuit.
- An on/off switch 51 in the form of a transistor is provided for this purpose. When a logic 1 from a control circuit 52 is applied to the gate of the transistor it is turned on and provides power to the oscillator. A logic 0 turns the transistor off and oscillation ceases.
- the output of the oscillator 50 is fed to a primary winding of a transformer 53 which has two centre-tapped secondary windings.
- the upper secondary of the transformer 53 then simply acts as a short circuit to connect the gates of the upper MOSFETS IC 2 -IC 5 through their networks to ground via a resistor (R 21 ) connected to the centre tap turning them on.
- R 21 resistor
- the lower MOSFETs IC 6 -IC 9 are turned on by the lower secondary.
- the output from the circuit shown in FIG. 5 is taken from the output terminals 55 a and 55 b which can be suitable for connection to a twisted pair of wires or a coaxial cable.
- the operational cycle is as follows:
- the charging path from the positive to capacitor 20 a is from an input socket 51 to transformers T 3 to inductor T 1 to IC 2 /D 2 to IC 2 /S 2 to IC 2 /S 1 to IC 2 /D 1 to C 20 a.
- the return path from the lower end of capacitor 20 a is IC 9 /D 1 to IC 9 /S 1 to IC 9 /S 2 to IC 9 /D 1 to inductor T 1 to socket 51 .
- Capacitor 20 a is charged up when the MOSFETs in IC 2 and IC 9 are switched on.
- capacitor 20 b When capacitor 20 a is charging up, capacitor 20 b is discharging into the load via IC 4 , IC 6 , inductor T 4 and terminals 55 a and 55 b.
- the discharge path for capacitor 20 a is via IC 5 , IC 8 , inductor T 4 and terminals 55 a and 55 b.
- capacitor 20 a When capacitor 20 a is discharging, capacitor 20 b is being charged.
- the charge path for capacitor 20 b is similar to that for capacitor 20 a but via IC 3 and IC 7 .
- the transformer secondaries switch the MOSFETs on and off in the correct sequence to charge and discharge the capacitors 20 a and 20 b .
- the transformer secondaries switch the MOSFETs on and off in the correct sequence to charge and discharge the capacitors 20 a and 20 b .
- the upper MOSFETs, IC 2 , IC 5 , IC 3 and IC 4 are dual P-channel devices.
- the gate of a N-Channel MOSFET is positive with respect to its source, then that MOSFET is turned on.
- the lower MOSFETs IC 9 , IC 8 , IC 7 and IC 4 are dual N-channel devices.
- the output transformer 53 from the oscillator 50 has two centre tapped secondaries. One secondary controls the P-channel devices. The other secondary controls the N-channel devices. To save space, only the operation of the P-channel devices will be described.
- Each of the sources is connected to the centre tap secondary through a 100 nF capacitor (C 2 , C 5 , C 3 and C 4 ).
- the capacitor gives DC isolation, but allows AC to pass through. If they were not there, then all the MOSFET sources would be connected together, rendering the circuit non-operational.
- the upper half of the top secondary winding drives the gates of IC 5 and IC 3
- the lower half of the top secondary winding drives the gates of IC 2 and IC 4 .
- the gate drive to the MOSFETs is via drive circuits 62 - 69 each of which consists of a diode and resistor connected in parallel.
- the components compensate for a difference between the turn-on and turn-off delays in the MOSFETs. These delays, were they to occur, would mean that some MOSFETs are turned on for a short time when they should be turned off. The effect would be a small amount of ground current resulting in an imbalance in the currents in the twisted pair or co-axial cable.
- This circuit has been designed to operate over a wide temperature range up to 165° C. and has been found to perform satisfactorily.
- FIG. 6 is a more detailed arrangement of the circuit shown in FIG. 4 and indicates the signal communication through the circuit.
- C 5 and C 17 act as reservoir capacitors, which in conjunction with the inductors T 1 and T 4 , reduce the switching spikes and ripple.
- the main path for the communication is via C 18 .
- a parallel and very necessary path is between the two windings of T 3 .
- This wound component acts as both a transformer for communications and also as a dual choke to further reduce the switching spikes and ripple.
- the two windings of T 1 share the same core, but T 1 is not a transformer, which is why the two windings are shown separate from each other. The same applies to T 4 .
- the core shared by the two wind of each inductor been omitted from the figure for clarity purposes.
- the reason for sharing the same core is that the net dc flux is zero due to cancellation. This enables the size of the component to be kept small and prevents saturation, particularly at high temperature.
Abstract
A downhole measurement assembly comprising a metal casing housing a plurality of tool sections, one of which includes a detector sensitive to a magnetic field, and a DC power supply for said tool sections, the power supply and the tool sections being electrically connected to the casing, characterised in that the power supply is connected to at least one tool section via a switching circuit and a conductor arrangement, the switching circuit comprising a capacitor, a plurality of switches and control means operative alternately to charge the capacitor from the DC supply and discharge the capacitor through said at least one tool section using the conductor arrangement so as to inhibit the generation of an electromagnetic field in the conductor arrangement between the capacitor and the said at least one tool.
Description
- The present invention relates to downhole measurement assemblies and more particularly to the electrical power supply arrangement for such assemblies.
- The oil and gas industry employs a variety of information gathering downhole tools during exploration and drilling of wells. These tools provide such information as hole inclination and azimuth, temperature, radioactivity, or resistivity. These tools are encased in non-magnetic stainless steel cylindrical pressure cases. By their nature, these tools have a large length to diameter ratio. The number of tools that have been introduced over the years has increased. Each tool is aligned serially down the drill string, and power is connected to each in parallel on a bus, which also allows communication between the tools and the transmission of signals to the surface. Traditionally, the pressure case of each tool is grounded and is the return path for DC current. Until recently, the directional measurement tool was always the one furthest down the hole and part of the directional measurement tool is an array of fluxgate magnetometers situated at the bottom of the tool in a module known as the stack. These magnetometers respond to the earth's magnetic field. Recently, other tools have been placed below the directional package and the power required by such tools results in current flowing in wire which passes the magnetometers and which in turn generates an electromagnetic field which causes errors in the readings produced by the magnetometers.
- Historically, the pressure cases of the downhole tools have always been grounded and connected to the system zero volts. This means that if conventional current carrying conductors are replaced in the region of the magnetometers by say a twisted pair or a coaxial cable, but otherwise the electrical arrangements remain unaltered, the current in the two conductors of the twisted pair or coaxial cable will be unbalanced as some current will flow through the parallel path of the pressure cases. In fact, most of the current will flow through the pressure case as it is a much better conductor.
- It is an object of the present invention to enable a fully grounded downhole measurement assembly to pass direct current in either direction without the current carrying conductors generating an electromagnetic field.
- The present invention provides a downhole measurement assembly comprising a metal casing housing a plurality of tool sections, one of which includes a detector sensitive to a magnetic field, and a DC power supply for said tool sections, the power supply and the tool sections being electrically connected to the casing, characterised in that the power supply is connected to at least one tool section via a switching circuit and a conductor arrangement, the switching circuit comprising a capacitor, a plurality of switches and control means operative to alternately charge the capacitor from the DC supply and discharge the capacitor through said at least one tool section using the conductor arrangement so as to inhibit the generation of an electromagnetic field in the conductor arrangement between the capacitor and the said at least one tool.
- In order that the present invention be more readily understood, an embodiment thereof will now be described by way of example with reference to the accompanying drawings in which:—
-
FIG. 1 is a diagrammatic representation of a downhole measurement assembly for explaining the present invention; -
FIG. 2 shows a basic circuit diagram for explaining the principle underlying the present invention; -
FIG. 3 shows a basic circuit diagram of a modification of the circuit shown inFIG. 2 ; -
FIG. 4 shows a more detailed circuit diagram of the circuit shown inFIG. 3 ; and -
FIGS. 5 a and b show a block diagram of a practical circuit of the present invention; and -
FIG. 6 shows a more detailed circuit diagram of the circuit shown ifFIG. 4 . - Referring now to
FIG. 1 , this shows a diagrammatic representation of adownhole measurement assembly 1 which comprises a plurality ofindividual tools 3 encased in non-magnetic stainless steel cylindrical pressure cases which are represented by theconductor 2 and which are mechanically and electrically connected together and also grounded. Thetools 3 are supplied with DC power from apower supply 4 one side of which is also grounded. Astack 5 which includes an array of fluxgate magnetometers is located towards the bottom of theassembly 1 below theindividual tools 3 but in this case other tools represented by theblock 7 are shown in a position on the other side of thestack 5 from thepower supply 4. This means that current for theother tools 7 has to be carried by conductors past thestack 5 and this in turn results in the generation of electromagnetic fields in the region of thestack 5 which causes in the output from thestack 5 to be inaccurate. - It has been found that simply shielding the current carrying conductor in the region of the
stack 5 is not possible, as the shield itself will cause disruption of the earth's magnetic field and also, as mentioned above, simply using a twisted pair or coaxial cable is also not sufficient if one wishes to retain the basic structure of the downhole assembly utilising the grounded pressure cases of the individual tools. - The present invention proposes to use a twisted pair or coaxial cable for the current carrying conductors but which allows the pressure cases to be electrically connected together in such a manner that they carry no current. This is achieved by utilising a capacitor connected by a switching network as will be explained in relation to
FIG. 2 . - As in the case of
FIG. 1 , one side of theDC supply 4 is connected to the pressure casing 1 a of the downhole measurement assembly which is in turn grounded. Acapacitor 20 is connected between the poles of a two-pole electronic changeover switch which in one position of the switch accumulates charge from the supply and, when the switch is changed over to its other position, allows the capacitor to transfer its charge to one or more downhole tools which are represented by theload 24. It can be seen that although the grounds are connected, no current can flow between them. Thus, all the current delivered to the downhole tools represented by theload 24 must flow in theconductors electronic changeover switch 22 and the downhole tools. Theseconductors switch 22 several thousand times a second. -
FIG. 3 shows an improved arrangement of the circuit shown inFIG. 2 . The improved arrangement employs twocapacitors electronic changeover switch conductor 25 is also used as a communications bus in many downhole tool arrangements. -
FIG. 4 shows a more practical circuit diagram of the circuit shown inFIG. 3 and inFIG. 4 the two-pole changeover switches have been replaced by semiconductor switches in the form of MOSFETs. It is preferred to use P-channel MOSFETs for switches SW1 to SW4 and N-channel MOSFETs for switches SW5 to SW8. Although it is not shown inFIG. 4 , an oscillator is provided in order to drive the MOSFET switches. The positive pole of theDC power supply 4 to thecapacitor 20 a is via MOSFET switch SW1 when closed and the other side ofcapacitor 20 a is connected to the negative terminal of theDC power supply 4 via the MOSFET switch SW5. In this way,capacitor 20 a charges. At the same time,capacitor 20 b is connected to and discharges into the load via the closed MOSFET switches SW4 and SW8. On changeover, the switches SW1, SW5, SW4, and SW8 are opened and the switches SW2, SW6 close which allows thecapacitor 20 a to discharge through the load while the MOSFET switches SW3 and SW7 are also closed to allow thecapacitor 20 b to be charged from thepower supply 4. -
FIGS. 5 a and 5 b when combined at conductors A-J show a block diagram of a practical circuit diagram for implementing the arrangement shown inFIG. 4 . The same component numbers and designations are used inFIGS. 5 a and 5 b as are used inFIG. 4 and consequently a detailed description of the operation ofFIG. 5 will not be given. Suffice to say that inFIG. 5 a, the oscillator is now shown and represented by thereference numeral 50. In the present example, it operates at about 53 KHz and controls the MOSFETs SW1 to SW8. The frequency is not particularly critical but operation has been found to be optimal with a frequency in theregion 50 KHz to 65 KHz. - When the circuit is operating, the current taken by it is approximately 16 mA. This is due to the current required by the oscillator and amplifier and the current required to switch the MOSFETs, some of which have a gate capacitance of up to 1.5 nF. When it is merely required to pass current past the stack without the need for preventing magnetic interference, current can be saved by turning off the oscillator, in which case the upper and lower switches are short circuit. An on/
off switch 51 in the form of a transistor is provided for this purpose. When alogic 1 from acontrol circuit 52 is applied to the gate of the transistor it is turned on and provides power to the oscillator. A logic 0 turns the transistor off and oscillation ceases. - The output of the
oscillator 50 is fed to a primary winding of atransformer 53 which has two centre-tapped secondary windings. The upper secondary of thetransformer 53 then simply acts as a short circuit to connect the gates of the upper MOSFETS IC2-IC5 through their networks to ground via a resistor (R21) connected to the centre tap turning them on. Similarly, the lower MOSFETs IC6-IC9 are turned on by the lower secondary. - In normal forward operation, that is with the power supply located above the tools in the downhole measurement assembly and providing current to the lower tools, current flows through transformer T3 (
FIG. 5 b) and inductor T1 (FIG. 5 a) to R7 and R5. Should it be required for current to flow in the reverse direction, clearly the upper MOSFETs have to be turned on to provide current to R5 and R7. In the circuit shown inFIG. 5 , this will always happen as the gates of the upper MOSFETs will be connected to the lower supply via R21. - The output from the circuit shown in
FIG. 5 is taken from theoutput terminals - The operational cycle is as follows:
- The charging path from the positive to capacitor 20 a is from an
input socket 51 to transformers T3 to inductor T1 to IC2/D2 to IC2/S2 to IC2/S1 to IC2/D1 to C20 a. - The return path from the lower end of
capacitor 20 a is IC9/D1 to IC9/S1 to IC9/S2 to IC9/D1 to inductor T1 tosocket 51. -
Capacitor 20 a is charged up when the MOSFETs in IC2 and IC9 are switched on. - When capacitor 20 a is charging up,
capacitor 20 b is discharging into the load via IC4, IC6, inductor T4 andterminals - The discharge path for
capacitor 20 a is via IC5, IC8, inductor T4 andterminals - When capacitor 20 a is discharging,
capacitor 20 b is being charged. - The charge path for
capacitor 20 b is similar to that forcapacitor 20 a but via IC3 and IC7. - The transformer secondaries switch the MOSFETs on and off in the correct sequence to charge and discharge the
capacitors - Consider the P-channel MOSFETs.
- The
output transformer 53 from theoscillator 50 has two centre tapped secondaries. One secondary controls the P-channel devices. The other secondary controls the N-channel devices. To save space, only the operation of the P-channel devices will be described. - Each of the sources is connected to the centre tap secondary through a 100 nF capacitor (C2, C5, C3 and C4). The capacitor gives DC isolation, but allows AC to pass through. If they were not there, then all the MOSFET sources would be connected together, rendering the circuit non-operational.
- The upper half of the top secondary winding drives the gates of IC5 and IC3, while the lower half of the top secondary winding drives the gates of IC2 and IC4.
- The gate drive to the MOSFETs is via drive circuits 62-69 each of which consists of a diode and resistor connected in parallel. The components compensate for a difference between the turn-on and turn-off delays in the MOSFETs. These delays, were they to occur, would mean that some MOSFETs are turned on for a short time when they should be turned off. The effect would be a small amount of ground current resulting in an imbalance in the currents in the twisted pair or co-axial cable.
- This circuit has been designed to operate over a wide temperature range up to 165° C. and has been found to perform satisfactorily.
- It is known that power may be passed up and down a downhole tool so as to allow communication between the tools and transmission of signals to the surface. The present invention preferably utilises the 1553 signal transmission and reception to supply power throughout the tool. However it will be appreciated that other communication standards may be utilised.
FIG. 6 is a more detailed arrangement of the circuit shown inFIG. 4 and indicates the signal communication through the circuit. - The type of communication we are dealing with is where a signal is superimposed on the supply line. It is fed into transmitter/receivers through a transformer. Referring to
FIG. 6 , C5 and C17 act as reservoir capacitors, which in conjunction with the inductors T1 and T4, reduce the switching spikes and ripple. The main path for the communication is via C18. A parallel and very necessary path is between the two windings of T3. This wound component acts as both a transformer for communications and also as a dual choke to further reduce the switching spikes and ripple. The two windings of T1 share the same core, but T1 is not a transformer, which is why the two windings are shown separate from each other. The same applies to T4. The core shared by the two wind of each inductor been omitted from the figure for clarity purposes. The reason for sharing the same core is that the net dc flux is zero due to cancellation. This enables the size of the component to be kept small and prevents saturation, particularly at high temperature.
Claims (9)
1. A downhole measurement assembly comprising a metal casing housing a plurality of tool sections, one of which includes a detector sensitive to a magnetic field, and a DC power supply for said tool sections, the power supply and the tool sections being electrically connected to the casing, characterised in that the power supply is connected to at least one tool section via a switching circuit and a conductor arrangement, the switching circuit comprising a capacitor, a plurality of switches and control means operative alternately to charge the capacitor from the DC supply and discharge the capacitor through said at least one tool section using the conductor arrangement so as to inhibit the generation of an electromagnetic field in the conductor arrangement between the capacitor and the said at least one tool.
2. An assembly according to claim 1 wherein the switching circuit includes a plurality of electrically controlled switches.
3. An assembly according to claim 2 wherein the electrically controlled switches are MOSFETs.
4. An assembly according to claim 1 wherein the control circuit is an oscillator.
5. An assembly according to claim 4 wherein a switch is provided for switching off the oscillator.
6. An assembly according to claim 4 wherein the oscillator operates in the range of 50-65 KHz.
7. An assembly according to claim 1 wherein there are two capacitors connected to the power supply by switches such that as one capacitor is connected to the power supply so as to be charged, the other capacitor is connected to said at least one tool section so as to provide power thereto.
8. An assembly according to claim 1 wherein the conductor arrangement comprises a twisted pair of conductors.
9. An assembly according to claim 1 wherein the conductor arrangement is a coaxial cable.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US12/472,152 US7928605B2 (en) | 2003-02-19 | 2009-05-26 | Electrical power supply arrangement for a downhole measurement assembly |
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
AUY0303875.9 | 2003-02-19 | ||
GB0303875A GB0303875D0 (en) | 2003-02-19 | 2003-02-19 | Electrical power supply arrangement for a downhole measurement assembly |
PCT/GB2004/000629 WO2004075369A2 (en) | 2003-02-19 | 2004-02-18 | Electrical power supply arrangement for a downhole measurement assembly |
Related Child Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US12/472,152 Continuation US7928605B2 (en) | 2003-02-19 | 2009-05-26 | Electrical power supply arrangement for a downhole measurement assembly |
Publications (1)
Publication Number | Publication Date |
---|---|
US20060232138A1 true US20060232138A1 (en) | 2006-10-19 |
Family
ID=9953343
Family Applications (2)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US10/546,056 Abandoned US20060232138A1 (en) | 2003-02-19 | 2004-02-18 | Electrical power supply arrangement for a downhole measurement assembly |
US12/472,152 Expired - Fee Related US7928605B2 (en) | 2003-02-19 | 2009-05-26 | Electrical power supply arrangement for a downhole measurement assembly |
Family Applications After (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US12/472,152 Expired - Fee Related US7928605B2 (en) | 2003-02-19 | 2009-05-26 | Electrical power supply arrangement for a downhole measurement assembly |
Country Status (8)
Country | Link |
---|---|
US (2) | US20060232138A1 (en) |
EP (2) | EP1595166A2 (en) |
AU (1) | AU2004213958B2 (en) |
BR (1) | BRPI0406205A (en) |
CA (1) | CA2494170C (en) |
GB (1) | GB0303875D0 (en) |
NO (1) | NO20052091L (en) |
WO (1) | WO2004075369A2 (en) |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20090243399A1 (en) * | 2003-02-19 | 2009-10-01 | Halliburton Energy Services, Inc. | Electrical power supply arrangement for a downhole measurement assembly |
WO2016076846A1 (en) * | 2014-11-12 | 2016-05-19 | Halliburton Energy Services, Inc. | Well detection using induced magnetic fields |
US20160299252A1 (en) * | 2014-10-22 | 2016-10-13 | Halliburton Energy Services, Inc. | Magnetic sensor correction for field generated from nearby current |
JP2020137298A (en) * | 2019-02-21 | 2020-08-31 | 公益財団法人鉄道総合技術研究所 | Capacitor and insulation circuit |
Families Citing this family (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20100156512A1 (en) * | 2007-06-13 | 2010-06-24 | Semiconductor Components Industries, L.L.C. | Charge pump controller and method therefor |
US9856722B2 (en) | 2014-03-14 | 2018-01-02 | General Electric Company | Methods and systems for controlling voltage switching |
GB2535236A (en) * | 2015-02-16 | 2016-08-17 | Ge Oil & Gas Uk Ltd | Retrofit power switching and repeating module |
US9893631B2 (en) * | 2015-09-23 | 2018-02-13 | Toyota Motor Engineering & Manufacturing North America, Inc. | Non-isolated DC-DC conversion circuit configured for capacitive and magnetic power transfer |
US10612344B2 (en) | 2016-01-12 | 2020-04-07 | Halliburton Energy Services, Inc. | Downhole control and sensing system |
US10753191B2 (en) | 2016-06-28 | 2020-08-25 | Baker Hughes, A Ge Company, Llc | Downhole tools with power utilization apparatus during flow-off state |
US11025059B2 (en) | 2016-10-31 | 2021-06-01 | Baker Hughes Oilfield Operations Llc | Switch systems for controlling conduction of multi-phase current |
WO2018178607A1 (en) | 2017-03-31 | 2018-10-04 | Metrol Technology Ltd | Monitoring well installations |
Citations (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3459956A (en) * | 1966-08-25 | 1969-08-05 | Schlumberger Technology Corp | Power supply system for well logging |
US5187421A (en) * | 1988-08-30 | 1993-02-16 | Kabushiki Kaisha Enu-Esu | Electrostatic transformer |
US5596489A (en) * | 1994-01-14 | 1997-01-21 | Intel Corporation | Capacitive transformer having a switch responsive to clock signals |
US5744877A (en) * | 1997-01-13 | 1998-04-28 | Pes, Inc. | Downhole power transmission system |
US6088294A (en) * | 1995-01-12 | 2000-07-11 | Baker Hughes Incorporated | Drilling system with an acoustic measurement-while-driving system for determining parameters of interest and controlling the drilling direction |
US6300844B1 (en) * | 1999-01-20 | 2001-10-09 | Telefonaktiebolaget Lm Ericsson (Publ) | Oscillator starting method |
US6392317B1 (en) * | 2000-08-22 | 2002-05-21 | David R. Hall | Annular wire harness for use in drill pipe |
Family Cites Families (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
BE757746A (en) * | 1969-12-22 | 1971-04-01 | Ibm | ELECTRICAL POWER SUPPLY DEVICE WITHOUT TRANSFORMER |
JPS5814224A (en) * | 1981-07-17 | 1983-01-27 | Nippon Gakki Seizo Kk | Power supply circuit |
EP1131882A1 (en) * | 1998-11-19 | 2001-09-12 | Infineon Technologies AG | Power supply device and switching arrangement with said power supply device |
GB0303875D0 (en) * | 2003-02-19 | 2003-03-26 | Halliburton Man Ltd | Electrical power supply arrangement for a downhole measurement assembly |
-
2003
- 2003-02-19 GB GB0303875A patent/GB0303875D0/en not_active Ceased
-
2004
- 2004-02-18 EP EP20040712097 patent/EP1595166A2/en not_active Withdrawn
- 2004-02-18 BR BRPI0406205 patent/BRPI0406205A/en not_active IP Right Cessation
- 2004-02-18 CA CA 2494170 patent/CA2494170C/en not_active Expired - Lifetime
- 2004-02-18 EP EP20060026580 patent/EP1777801A3/en not_active Withdrawn
- 2004-02-18 WO PCT/GB2004/000629 patent/WO2004075369A2/en active Application Filing
- 2004-02-18 US US10/546,056 patent/US20060232138A1/en not_active Abandoned
- 2004-02-18 AU AU2004213958A patent/AU2004213958B2/en not_active Ceased
-
2005
- 2005-04-29 NO NO20052091A patent/NO20052091L/en not_active Application Discontinuation
-
2009
- 2009-05-26 US US12/472,152 patent/US7928605B2/en not_active Expired - Fee Related
Patent Citations (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3459956A (en) * | 1966-08-25 | 1969-08-05 | Schlumberger Technology Corp | Power supply system for well logging |
US5187421A (en) * | 1988-08-30 | 1993-02-16 | Kabushiki Kaisha Enu-Esu | Electrostatic transformer |
US5596489A (en) * | 1994-01-14 | 1997-01-21 | Intel Corporation | Capacitive transformer having a switch responsive to clock signals |
US6088294A (en) * | 1995-01-12 | 2000-07-11 | Baker Hughes Incorporated | Drilling system with an acoustic measurement-while-driving system for determining parameters of interest and controlling the drilling direction |
US5744877A (en) * | 1997-01-13 | 1998-04-28 | Pes, Inc. | Downhole power transmission system |
US6300844B1 (en) * | 1999-01-20 | 2001-10-09 | Telefonaktiebolaget Lm Ericsson (Publ) | Oscillator starting method |
US6392317B1 (en) * | 2000-08-22 | 2002-05-21 | David R. Hall | Annular wire harness for use in drill pipe |
Cited By (11)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20090243399A1 (en) * | 2003-02-19 | 2009-10-01 | Halliburton Energy Services, Inc. | Electrical power supply arrangement for a downhole measurement assembly |
US7928605B2 (en) | 2003-02-19 | 2011-04-19 | Halliburton Energy Services, Inc. | Electrical power supply arrangement for a downhole measurement assembly |
US20160299252A1 (en) * | 2014-10-22 | 2016-10-13 | Halliburton Energy Services, Inc. | Magnetic sensor correction for field generated from nearby current |
US10481296B2 (en) * | 2014-10-22 | 2019-11-19 | Hallibunon Energy Services, Inc. | Magnetic sensor correction for field generated from nearby current |
WO2016076846A1 (en) * | 2014-11-12 | 2016-05-19 | Halliburton Energy Services, Inc. | Well detection using induced magnetic fields |
US9529111B2 (en) | 2014-11-12 | 2016-12-27 | Halliburton Energy Services, Inc. | Well detection using induced magnetic fields |
GB2545596A (en) * | 2014-11-12 | 2017-06-21 | Halliburton Energy Services Inc | Well detection using induced magnetic fields |
AU2014411408B2 (en) * | 2014-11-12 | 2018-05-10 | Halliburton Energy Services, Inc. | Well detection using induced magnetic fields |
GB2545596B (en) * | 2014-11-12 | 2020-09-23 | Halliburton Energy Services Inc | Well detection using induced magnetic fields |
JP2020137298A (en) * | 2019-02-21 | 2020-08-31 | 公益財団法人鉄道総合技術研究所 | Capacitor and insulation circuit |
JP7114506B2 (en) | 2019-02-21 | 2022-08-08 | 公益財団法人鉄道総合技術研究所 | Capacitor and isolation circuit |
Also Published As
Publication number | Publication date |
---|---|
EP1777801A3 (en) | 2011-03-16 |
AU2004213958B2 (en) | 2009-07-02 |
BRPI0406205A (en) | 2005-08-09 |
CA2494170A1 (en) | 2004-09-02 |
AU2004213958A1 (en) | 2004-09-02 |
EP1595166A2 (en) | 2005-11-16 |
US20090243399A1 (en) | 2009-10-01 |
WO2004075369A3 (en) | 2005-03-24 |
NO20052091L (en) | 2005-04-29 |
GB0303875D0 (en) | 2003-03-26 |
US7928605B2 (en) | 2011-04-19 |
EP1777801A2 (en) | 2007-04-25 |
CA2494170C (en) | 2013-11-19 |
WO2004075369A2 (en) | 2004-09-02 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US7928605B2 (en) | Electrical power supply arrangement for a downhole measurement assembly | |
US5726615A (en) | Integrated-magnetic apparatus | |
US7369026B2 (en) | Method and apparatus for substantially reducing electrical displacement current flow between input and output circuits coupled to input and output windings of an energy transfer element | |
US9478351B2 (en) | Isolation transformer for use in isolated DC-to-DC switching power supply | |
CN102856988B (en) | The energy transmission system of inductance resonance coupling and method | |
US7142440B2 (en) | Ripple-current reduction for transformers | |
US8379415B2 (en) | Systems and methods for reducing EMI in switch mode converter systems | |
US5394065A (en) | Circuit for supplying current to a discharge tube | |
US5631815A (en) | High voltage power supply | |
EP0410526B1 (en) | Generator for generating an electric voltage | |
US5355293A (en) | Low-voltage DC power supply | |
US9831789B2 (en) | Switched mode drive circuit | |
US6426610B1 (en) | Controlled ferroresonant constant current source | |
US4194128A (en) | Ripple control systems | |
US7193397B2 (en) | Voltage converter | |
EP3572846B1 (en) | High power transformer and transmitter for geophysical measurements | |
US6633493B2 (en) | Inherently short-circuit resistant power distribution system | |
FI113502B (en) | Power supply of an electric switch | |
JPH05304451A (en) | Dc high-voltage solid switching device | |
US6069413A (en) | Apparatus for generating an alternating magnetic field | |
US6606258B1 (en) | Voltage reference translation system and an electronic circuit employing the same | |
FI88233C (en) | RESONANSSTROEMKAELLA |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
AS | Assignment |
Owner name: HALLIBURTON ENERGY SERVICES, INC., TEXAS Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:WILLIAMS, PERCIVAL F;REEL/FRAME:017724/0254 Effective date: 20050208 |
|
STCB | Information on status: application discontinuation |
Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION |