Method for measuring spectrum parameters of formation outcrop and rock mass

Patent metadata

Field	Value
Publication number	US-2025060502-A1
Application number	US-202418937177-A
Country	US
Kind code	A1
Filing date	Nov 5, 2024
Priority date	May 29, 2024
Publication date	Feb 20, 2025
Grant date	—

Abstract

A device and method for measuring spectrum parameters of a formation outcrop and a rock mass are provided. An excitation signal is generated by a direct digital synthesis (DDS) module of a signal transmission portion. A constant voltage mode or a constant current mode is adopted for observation. After the signal passes through a constant voltage/constant current module, a constant high-voltage signal source or a current source signal with constant current output is formed and output to ground through grounding electrodes A and B to establish a stable observation signal field source. Geoelectric response information under the excitation of each frequency signal is acquired by a signal receiving portion through grounding electrodes M and N, processed and send out to a microcontroller unit (MCU) for display and storage. The spectrum parameters at different depths are observed by adjusting geometric dimensions of AB and MN.

First claim

What is claimed is:

1 . A device for measuring spectrum parameters of a formation outcrop and a rock mass, comprising:
a signal transmission portion; and a signal receiving portion; wherein the signal transmission portion comprises a grounding electrode A, a grounding electrode B, a microcontroller unit (MCU), a direct digital synthesis (DDS) module, a polarity conversion module, a signal amplification module, a mode switching module, a constant voltage/constant current module, a power amplification module and a current acquisition module; the MCU, the DDS module, the polarity conversion module, the signal amplification module, the mode switching module, the constant voltage/constant current module and the power amplification module are connected in sequence; an output signal of the power amplification module is configured to be output to ground through the grounding electrode A and the grounding electrode B to form a first transmission loop circuit; an input end of the current acquisition module is connected to the power amplification module, and an output end of the current acquisition module is connected to the MCU; a frequency signal generated by the signal transmission portion is configured to be sequentially subjected to polarity conversion, signal amplification and connection to the grounding electrode A and the grounding electrode B to form a second transmission loop circuit; and the current acquisition module is configured to record information about output voltage, current and time of each frequency point to the MCU in real time; and the signal receiving portion comprises a grounding electrode M, a grounding electrode N, a pre-amplification module, a notch/pass-through module, a bandpass filtration module, a programmable gain amplification module and an analog-digital converter (ADC) module; the grounding electrode M and the grounding electrode N are connected to the pre-amplification module; the pre-amplification module, the notch/pass-through module, the bandpass filtration module, the programmable gain amplification module, the ADC module and the MCU are connected in sequence; the signal receiving portion is configured to acquire a frequency response signal of an underground medium through the grounding electrode M and the grounding electrode N, such that the frequency response signal is sequentially subjected to signal pre-amplification, signal conditioning, ADC conversion and post-processing by the MCU, so as to form spectrum characteristic information of the formation outcrop or the rock mass within a preset frequency bandwidth.

2 . The device of claim 1 , further comprising:
a communication module; a display module; a keyboard module; and a storage module; wherein the MCU is connected to the communication module, the display module, the keyboard module and the storage module.

3 . The device of claim 1 , wherein the signal transmission portion is configured to generate an excitation signal at a frequency point of 2″ Hz, and n is an integer selected from −7 to 10; a 0.5-time frequency within the preset frequency bandwidth is configured to perform frequency encryption among each frequency point; and a final signal frequency range is 0.01 Hz-1 kHz.

4 . The device of claim 1 , wherein the signal transmission portion is in a common clock mode with the signal receiving portion, such that signal transmission and signal receiving are completed based on the common clock mode, thereby detecting amplitude frequency information and phase frequency information of the formation outcrop or the rock mass on the basis of improving an anti-interference capability.

5 . The device of claim 1 , wherein the grounding electrode A, the grounding electrode B, the grounding electrode C and the grounding electrode D are arranged in a symmetrical quadrupole arrangement, such that the spectrum parameters of the formation outcrop or the rock mass at different depths within a preset depth range are observed by changing a geometric dimension of the grounding electrode A, the grounding electrode B, the grounding electrode C and the grounding electrode D.

6 . A method for measuring spectrum parameters of a formation outcrop and a rock mass using the device of claim 1 , comprising:
(1) selecting the formation outcrop or the rock mass as an observation object according to an exploration target requirement and a working area; lowering a grounding resistance of the grounding electrode A and the grounding electrode B by watering; connecting a first connecting wire to the grounding electrode A and the grounding electrode B to form a first connecting loop; measuring a first resistance value of the first connecting loop to estimate an output constant current or an output constant voltage; arranging the grounding electrode M and the grounding electrode N according to a requirement of a symmetrical quadrupole arrangement; connecting the grounding electrode M to a terminal of an M port of the device through a second connecting wire; and connecting the grounding electrode N to a terminal of an N port of the device through the second connecting wire to form a second connecting loop; (2) connecting an external direct current (DC) power supply to an input end of the power amplification module followed by polarity correctness check; and connecting the first connecting wire to terminals of an output end A and an output end B of the power amplification module; (3) powering on the device for preheating; and checking a connection status of the input end, the output end A and the output end B of the power amplification module, the grounding electrode A, the grounding electrode B, the grounding electrode M, the grounding electrode N, the first connecting wire and the second connecting wire; measuring a second resistance value of the first connecting loop; checking a connection status of the second connecting wire, the grounding electrode M and the grounding electrode N; measuring a resistance value of the second connecting loop; (4) after preheating the device for 5 min, generating and transmitting, by the signal transmission portion, a 1 Hz excitation signal, and observing and calculating a resistivity value of the observation object at this time; adjusting, by the signal transmission portion, an intensity of the output constant voltage or the output constant current; and sending out, by the signal transmission portion, each frequency point signal in the preset frequency bandwidth set by a frequency table in sequence; (5) picking up, by the signal transmission portion, the frequency response signal followed by checking to conform that the frequency response signal is normal; and starting acquisition; (6) saving information of each frequency point received by the signal receiving portion and current information sent by the signal transmission portion in the storage module; and (7) performing mapping processing in an upper computer followed by corresponding geological interpretation.

7 . The device of claim 6 , wherein in step (1), in a case where the observation object is a complete rock mass, a dough with a saturated copper sulfate solution is adopted as a coupling material coupled to the grounding electrode A, the grounding electrode B and the complete rock mass, thereby lowering the grounding resistance.

Assignees

• Univ Hunan Science & Technology

Inventors

• Cheng Hui
• Fu Guohong
• Liu Yan
• Liao Xiuying

Classifications

• G01V2003/084

  Sources · CPC title

• G01V2003/085

  Receivers · CPC title

• G01V3/083 Primary

  Controlled source electromagnetic [CSEM] surveying · CPC title

• Y02A90/30

  Assessment of water resources · CPC title

• G01V3/08 Primary

  operating with magnetic or electric fields produced or modified by objects or geological structures or by detecting devices (with electromagnetic waves G01V3/12) · CPC title