Remotely reconfigurable system for mapping subsurface geological anomalies

• US 20080136421A1
• Filed: 11/01/2007
• Published: 06/12/2008
• Est. Priority Date: 06/22/2006
• Status: Active Grant

• Current Assignee: Earth Systems Technologies, Inc.
• Original Assignee: Bryant Consultants Incorporated
• Inventors: Bryant, John, Salamat, Arash Tom, Willey, H. Michael, Leopold, Jerry, Lehmann, Guenter H., Edgar, Michael
• Granted Patent: US 7,788,049 B2
• Time in Patent Office: Days
• US Class Current: 324/357
• CPC Class Codes: G01V 1/22 Transmitting seismic signals to recording or processing apparatus
• CPC Class Codes: G01V 3/02 operating with propagation of electric current

Abstract

A method and apparatus are provided for detecting and transmitting geophysical data from a plurality of electrodes inserted into the soil utilizing a set of identical dynamically reconfigurable voltage control units located on each electrode and connected together by a communications and power cable. A test sequence is provided in each voltage control unit. Each voltage control unit records data measurements for transmission to a central data collector. Each voltage control unit incorporates and determines its positional relationship to other voltage control units by logging when the unit is attached to the electrode. Each voltage control unit I equipped with a magnetic switch for detecting when they are in contact with the electrode.

Claims

1. A system for collecting resistivity data from a subsurface media comprising:

a power distribution unit distributing an injection current, an operating power source and an operating ground to a set of interconnected voltage control units;

the power distribution unit further comprising a high voltage source, and a high voltage sink;

a reference electrode in contact with the geological surface, connected to the power distribution unit for defining a high voltage reference;

a current source connected to the power distribution unit;

a data collection unit connected to the power distribution unit;

an array of electrodes in contact with a geological surface, having at least a first electrode, a second electrode and a third electrode;

the set of interconnected voltage control units connected to the array of electrodes and in in data communication with the power distribution unit,

the set of interconnected voltage control units programmed to dispense the injection current into the array of electrodes in a predetermined pattern; and

the set of interconnected voltage control units programmed to measure the voltages between the array of electrodes and the reference electrode and to send a first signal to the power distribution unit related to the measured voltages.

2. The system of claim 1 wherein the current source is a battery.

3. The system of claim 1 wherein the data collector is programmed to receive a second signal from the power distribution unit related to the measured voltages and to store a dataset related to the measured voltages.

4. The system of claim 1 wherein the power distribution unit further comprises:

a first power converter connected to the current source and the set of interconnected voltage control units;

a high voltage power supply connected to the current source for supplying the injection current to the set of interconnected voltage control units;

a microprocessor for translating communications between the set of voltage control units and the data collection unit;

a voltmeter connected to the microprocessor for measuring the voltage at which the injection current is delivered; and

an ammeter connected to the microprocessor for measuring the amount of injection current delivered.

5. The system of claim 4 wherein the microprocessor is programmed to proportionally control the voltage from the high voltage source.

6. The system of claim 1 wherein each voltage control unit in the set of interconnected voltage control units further comprises:

a microcontroller;

volatile memory connected to the microcontroller;

non-volatile memory connected to the microcontroller;

an analog to digital converter connected to the microcontroller, attached to at least one electrode of the array of electrodes; and

attached to the high voltage reference so as to make a measurement of a voltage at the at least one electrode;

the microcontroller programmed to store the measurement in the volatile memory;

an upstream communications port and a downstream communications port;

a bi-directional transceiver connected to the upstream communications port and the downstream communications port and to the microcontroller;

a first solid state switch connected to the at least one electrode and the high voltage source, the first solid state switch being connected to and controlled by the microcontroller so as to operationally connect the high voltage source to the at least one electrode;

a second solid state switch connected to the at least one electrode and to the high voltage sink, the first solid state switch being connected to and controlled by the microcontroller so as to operationally connect the high voltage sink to the at least one electrode; and

a capacitor connected to the operating power source for storing and supplying energy to the microcontroller, the voltage meter, the nonvolatile memory, the analog to digital converter, the bi-directional transceiver, the first solid state switch and the second solid state switch when the operational power source is disconnected.

7. The system of claim 6 further comprising a housing, the housing having a connection connecting the at least one electrode and the first solid state switch, the second solid state switch, and the analog to digital converter;

the housing further comprising a magnet adjacent the at least one electrode.

8. The system of claim 6 further comprising a set of test sequence tables stored in the non-volatile memory.

9. A system for collecting resistivity data from a subsurface media comprising:

an array of electrodes in the subsurface media;

a power distribution unit connected to an electrode in the array of electrodes;

a set of voltage control units, wherein each voltage control unit of the set of voltage control units is connected to an electrode in the array of electrodes;

the power distribution unit programmed to send a high voltage signal to the set of voltage control units;

each voltage control unit of the set of voltage control units programmed to;

retrieve a test table from a memory upon receipt of the high voltage signal

reconfigurably connect the array of electrodes to the high voltage signal in a predetermined permutation;

reconfigurably take a voltage measurement from the array of electrodes; and

transmit the voltage measurement to a data collection unit.

10. The system of claim 9 wherein the test table includes a source connect instruction, a sink connect instruction and a measure instruction for each voltage control unit of the set of voltage control units.

11. The system of claim 9 wherein each voltage control unit of the set of voltage control units is further programmed to conduct a self test and activate an indicator upon a failure condition.

12. The system of claim 9 wherein each power distribution unit of the set of power distribution units is further programmed to conduct a self test and activate an indicator upon a failure condition.

13. The system of claim 9 wherein each voltage control unit includes a capacitor means serving as a sole power source when the operating power source is disconnected.

14. The system of claim 13 wherein the power distribution unit includes a low voltage source for changing the capacitor.

15. The system of claim 9 wherein the memory is resident in the voltage control unit.

16. The system of claim 9 wherein the memory is resident in a controller connected to the power distribution unit.

17. The system of claim 15 wherein the memory includes a plurality of test tables.

18. The system of claim 9 wherein each voltage control unit of the set of voltage control units is programmed to determine a positional relationship among the set of voltage control units.

19. The system of claim 18 wherein each voltage control unit of the set of voltage control units is programmed to transmit a signal unit related to the positional relationship to a predetermined pole position voltage control unit.

20. The system of claim 9 wherein the power distribution unit and each voltage control unit is connected in a serial fashion with a set of connection cables and wherein each of the connection cables of the set of connection cables is identical in structure.

21. The system of claim 9 wherein each voltage control unit of the set of voltage control units is identical in structure.

22. A method of gathering resistivity data from a subsurface media comprising:

providing an array of electrodes in the media;

providing a set of voltage control units connected by a set of cables;

connecting the set of voltage control units to the array of electrodes;

connecting the set of voltage control units to a power distribution unit in a serial connection;

registering a positional relationship of the set of voltage control units based on a connection time to the array of electrodes;

choosing a test sequence;

loading the test sequence into the set of voltage control units;

prompting the power distribution unit to send a high voltage signal to the set of voltage control units to activate the test sequence;

using the test sequence to reconfigurably adapt the set of voltage control units to inject a current signal into the subsurface media and take a set of voltage readings from the array of electrodes based on the current signal;

transmitting a data set related to the set of voltage readings to a data collection mode; and

using the set of voltage readings to derive a resistivity map.

23. The method of claim 22 wherein the step of registering the set of voltage control units further comprises:

generating a random number based on the receipt of a register signal;

broadcasting the random number to the set of voltage control units;

assigning a pole position voltage control unit from the set of voltage control units based on the random number;

assigning an order to the set of voltage control units based on the random number; and

storing the order in the pole position voltage control unit.

24. The method of claim 22 wherein the step of choosing a test sequence further includes forming a table comprised of a series of connection states related to a predetermined permutation of connections of the high voltage signal to the array of electrodes by each voltage control unit of the set of voltage control units.

25. The method of claim 24 wherein the step of forming includes the further step of choosing each connection state in the series of connection states one of the group of “

high voltage”

, “

sink” and

“

measure”

.

26. The method of claim 22 wherein the step of transmitting further comprises transmitting the data set on a data line in a time period based on the positional relationship.

27. The method of claim 22 wherein the step of loading further comprises loading a test sequence from a memory in each voltage control unit of the set of voltage control units.

28. The method of claim 22 wherein the step of loading further comprises loading a test sequence from a memory in the data collection mode.

29. A method of switching a current to an electrode inserted into a geological surface the method comprising:

providing a high voltage source for driving the current into the electrode;

providing a high voltage sink for sinking the current extracted from the electrode;

providing a charge pump device that produces an output charge;

providing a first signal line to charge the charge pump device;

providing a second signal line to pulse the charge pump device;

providing a third signal line to discharge the charge pump device;

providing a fourth signal line to a first transistor to connect and disconnect a ground signal to the charge pump;

providing a second transistor having the output charge of the charge pump appear on a second transistor gate, a source of the second transistor being connected to the high voltage sink and a drain of the second transistor being connected to the electrode;

sending a voltage on the first signal line and a set of voltage pulses on the second signal line to the charge pump to accumulate a charge so that the second transistor is caused to conduct between the high voltage source and the electrode;

removing a voltage on the fourth signal line to disconnect the ground signal from the charge pump;

discontinuing the charge to the charge pump by removing power from the first signal line and the second signal line;

floating an accumulated charge on the second transistor so that the second transistor continues to conduct;

sending a voltage on the fourth signal line to connect the ground signal to the charge pump; and

sending a voltage on the third signal line to discharge the accumulated charge on the second transistor so that the second transistor ceases to conduct between the high voltage source and the electrode.

30. A solid state switch apparatus for switching a high voltage signal onto an output pin in a connected state and off of the output pin in a disconnected state, the solid state switch being operationally powered by a supply voltage, the solid state switch capable of sustaining one of the group of the connected state and the disconnected state when the supply voltage is removed from the solid state switch, the solid state switch being comprised of:

an isolation transformer having;

an input DC power supply signal in one to one voltage relationship with an isolated output DC power supply signal;

an input A signal in a in one to one voltage relationship with an isolated output A signal;

an input B signal in a in one to one voltage relationship with an isolated output B signal;

an input ground signal in a in one to one voltage relationship with an output ground signal;

a charge pump with an input connected to the isolated output DC power supply signal and being driven by the isolated output A signal, the charge pump having an output charge at an output DC voltage larger than the input;

a first transistor connected to the output charge of the charge pump, the first transistor connected to the isolated output ground signal and further connected to the isolated B signal so that the isolated output signal B causes the first transistor to conduct the output charge of the charge pump to discharge to the isolated output ground;

a second transistor connected to the high voltage signal, the second transistor being connected to the output charge of the charge pump and further connected to the output pin, the output charge of the charge pump being connected to a gate input of the second transistor so that when a charge is produced on a gate input, the second transistor is caused to conduct the high voltage signal to the output pin;

a third transistor connected to the input ground signal, the third transistor connected to an external power off signal and further connected to an earthed ground so that the external power off signal causes the third transistor to conduct between the input ground signal and the earthed ground.

31. The solid state switch apparatus of claim 30 wherein a fourth transistor is connected to the high voltage signal, the fourth transistor connected to the output charge of the charge pump and further connected to the output pin, the output charge being connected to a gate input of the fourth transistor so that when a charge is produced on the gate input of the fourth transistor, the fourth transistor is caused to conduct the high voltage signal to the output pin;

32. The solid state switch apparatus of claim 30 wherein the output pin is connected to an electrode inserted into a geological surface so that a current may be sourced to the geological surface.

33. The solid state switch apparatus of claim 30 wherein the output pin is connected to an electrode inserted into a geological surface so that a current may be extracted from the geological surface.

34. A method of collecting geophysical resistivity data from subsurface media comprising the steps of:

deploying an array of electrodes dispersed in a pattern in the subsurface media;

providing a reference electrode;

providing an array of voltage control units correlated to the array of electrodes;

equipping each voltage control unit in the array of voltage control units with bi-directional data communications means for generating a data communication signal to and from the array of voltage control units;

providing a voltage measurement device in each voltage control unit in the array of voltage control units;

providing a power distribution unit, connected to the first voltage control unit, the power distribution unit supplying an injection current, an operational power, a control line and data communication signal to the array of voltage control units, the power distribution unit having a test button for a test start signal;

providing a high voltage source, connected to the power distribution unit, for supplying the injection current;

providing a high voltage sink, connected to the power distribution unit, for sinking an injection current return;

providing a proportional control means for ramping the high voltage source;

providing a means for activating and deactivating the operational power;

providing a capacitor in each voltage control unit of the array of voltage control units to store energy from the operational power when the operational power is activated; and

deliver energy to the array of voltage control units when the operational power is deactivated;

providing a current measuring device, in the power distribution unit, to measure the injection current;

providing a voltage measuring device, in the power distribution unit, to measure an injection voltage of the high voltage source line;

providing a data collector for collecting a set of test data, the set of test data comprising a set of measured voltages;

providing a voltage control switch in each voltage control unit of the array of voltage control units, the switch being in one connecting state from the group of connecting states;

(i) a first state of connecting the injection current to an electrode,

(ii) a second state of connecting the injection current return to an electrode, and

(iii) a third state of disconnection from the electrode;

cabling the array of control units together interconnecting in a serial fashion;

running a self-test on each voltage control unit of the array of voltage control units when operational power is activated;

providing a set of predefined test sequence tables, each test sequence table of the set of predefined sequence tables comprised of a table of tests, each test of the table of tests including a linear position parameter and an instruction parameter;

distributing a predefined test sequence table to the array of voltage control units;

attaching each voltage control unit in the array of voltage control units to the correlated electrode in the array of electrodes;

selecting a test sequence identifier associated with tone predefined test sequence table of the set of predefined test sequence tables; and

running a test associated with the test sequence identifier.

35. The method of claim 34 further including the step of manually recording a position of electrodes in the array of electrodes upon deployment.

36. The method of claim 34 wherein the step of running a self-test includes the steps of:

verifying a first status condition of a firmware system in a voltage control unit of the array of voltage control units; and

verifying a second status condition of a memory of the voltage control unit of the array of voltage control units.

37. The method of claim 36 further including the step of generating an error signal if one of the group of the first status condition and the second status condition is “

fail”

.

38. The method of claim 34 wherein the step of distributing a predefined test sequence includes the additional step of storing the predefined test sequence in a non-volatile memory.

39. The method of claim 34 wherein the step of distributing a predefined test sequence includes the additional step of:

storing the predefined test sequence in the data collector;

downloading the predefined test sequence from the data collector to each voltage control unit of the array of voltage control units;

storing the predefined test sequence into volatile memory at each voltage control unit of the array of voltage control units;

40. The method of claim 34 wherein the step of attaching each voltage control unit to the array of electrodes comprises the steps of:

attaching a first voltage control unit of the array of voltage control units to a first electrode in the array of electrodes;

activating the first voltage control unit, in which a first position and a first address for the first voltage control unit is assigned;

attaching a next voltage control unit of the array of voltage control units to a next electrode in the array of electrodes;

activating the next voltage control unit in which a second position and a second address for the next voltage control unit is assigned; and

repeating the step of activating the next voltage control unit for each voltage control unit of the array of voltage control units.

41. The method of claim 40 wherein the step of activating the first voltage control unit includes the further steps of:

generating a random address;

broadcasting the random address with the data communications means;

waiting for a response from the data communication means;

setting a position number of first voltage control unit to 1;

storing the random address and the position number in an address list in the first voltage control unit;

42. The method of claim 41 wherein the random address is generated by the first voltage control unit.

43. The method of claim 41 wherein the address list is kept in the volatile memory of the first voltage control unit.

44. The method of claim 40 wherein the step of activating the next voltage control unit includes the further steps of:

generating a random address in the next voltage control unit;

broadcasting the random address using the data communications means;

receiving a position number from an upstream voltage control unit in the array of voltage control units using the data communication means;

setting a position parameter of next voltage control to the position number;

storing the random address and the position number in an address list.

45. The method of claim 44 wherein the upstream voltage control unit is received is the first voltage control unit.

46. The method of claim 44 wherein the address list is stored in a volatile memory of an upstream voltage control unit of the set of voltage control units.

47. The method of claim 44 wherein the upstream voltage control unit is the first voltage control unit of the set of voltage control units.

48. The method of claim 44 including the additional steps of

checking that the random address is unique;

if the random address is not unique, then regenerating the random address;

if the random address is unique, then receiving a position number.

49. The method of claim 48 wherein the step of checking that the random address is unique includes the additional steps of:

comparing the random address with a set of addresses in an address list;

sending a predefined response to a voltage control unit of the set of voltage control units comprising;

a first signal if the random address is unique, and

a second signal if the random address is not unique.

50. The method of claim 34 wherein the method of selecting the test sequence identifier includes the further steps of:

entering a set of recorded positions of the array of electrodes into the data collector;

creating a test data file for holding test data; and

waiting for a signal to begin a test.

51. The method of claim 50 wherein the step of entering the set of recorded positions includes the step of transferring data between a handheld computing device and the data collector.

52. The method of claim 50 wherein the step of entering the set of recorded positions including the step of manually entering a set of alphanumeric characters into the data collector.

53. The method of claim 50 wherein the step of entering a signal includes the step of polling a test button on the power distribution unit;

54. The method of claim 50 including the additional steps of;

broadcasting the test sequence identifier to the array of voltage control units;

selecting a selected test sequence table associated with the selected test sequence identifier from the set of predefined test sequence tables from a persistently stored set of predefined test sequences in non-volatile memory in each voltage control unit of the array of voltage control units; and

selecting a test sequence from the selected test sequence table based on the position number.

55. The method of claim 50 including the additional steps of:

broadcasting the selected test sequence table from the data collection unit to the array of voltage control units;

downloading of the selected test sequence table during the broadcasting step by each voltage control unit of the array of voltage control units;

storing the selected test table in a volatile memory by each voltage control unit of the array of voltage control units; and

selecting a test sequence from the test sequence table wherein the selection is based on the position number.

56. The method of claim 34 wherein the step of running the test further comprises the steps of:

applying a low voltage of between about 0.1 and about 50 volts to a high voltage source line from the high voltage source;

sending the address list to the data collector;

turning off the high voltage source line;

setting the number of tests, T, to a maximum number of tests;

setting a test index number, i, to a value of 1;

sending the test index number to the array of voltage control units using the data communication means;

setting the voltage control switch of each voltage control unit in the array of voltage control units to the third state;

setting the voltage control switch of a first voltage control unit in the array of voltage control units to the first state and setting the voltage control switch of a second voltage control unit in the array of voltage control units to the second state;

ramping the voltage of the high voltage source line from 0 (zero) to V in a time R, wherein V is between 500V and 1500V, and R is between 0.5 sec and 5 seconds;

switching off the operational power source during each voltage control of the set of voltage control units with an internal capacitor;

measuring a set of electric potentials on the array of electrodes, except for electrodes connected to the first voltage control unit and the second voltage control unit, the array of voltage control units storing the set of measured electric potentials;

measuring the injection current and the injection voltage;

activating the operational power source;

switching voltage control units of the first voltage control unit and the second voltage control unit to the third state;

transmitting the measured injection current value and the measured injection voltage value to the data collector over the data communication means;

transmitting the set of measured electric potentials to the data collector over the data communication means;

storing the measured injection current value, the measured injection voltage value and the set of electric potentials in a test data file in the data collector;

incrementing the test index, i;

i=i+1;

repeating the previous steps in order beginning with step of sending the test index number to the voltage control units, if “

i”

is less than or equal to “

f”

, and continuing to the next step if “

i”

is greater than “

T”

; and

powering down the power distribution unit and the array of voltage control units.

57. The method of claim 56 including the additional step of activating a safety signal before activating the high voltage.

58. The method of claim 56 wherein the step of transmitting the measured electric potentials is accomplished by the steps of:

assigning a time slot according to a physical position of each voltage control unit in the array of voltage control units;

transmitting a set of measured data packets containing the set of electric potentials to the data collector in the assigned time slot.