In-hole geological and geophysical prospecting method and system based on direct current method-transient electromagnetic method coupling

Abstract

The invention provides a direct current method-transient electromagnetic method coupling in-hole geology and geophysical prospecting method and system. The method comprises the following steps: acquiring resistance information of a target area by adopting a direct current method; a transient electromagnetic method is adopted to collect a secondary field attenuation signal of the target area; coupling the resistance information and the secondary field attenuation signal of the target area, and comprehensively obtaining a detection result of the target area; according to the application, the direct current method and the transient electromagnetic method are simultaneously adopted to acquire related information of the target area, and the resistance information and the secondary field attenuation signal of the target area are coupled, so that the advantages of the two methods are integrated, and the geological exploration accuracy is improved.

Description

Technical Field

[0001] This application relates to the field of geological exploration technology, and specifically relates to a borehole geological geophysical exploration method and system based on the coupling of direct current method - transient electromagnetic method. Background Art

[0002] The direct current method utilizes the resistivity difference and polarization rate difference of rocks and ores due to electrical property differences. The measured parameters include apparent resistivity and apparent polarization rate, etc. The direct current methods using artificial field sources include resistivity profiling method, resistivity sounding method, charging method, direct current induced polarization method, etc. The direct current method using natural field sources includes natural electric field method, etc. It is sensitive to low-resistance anomalies, but the detection depth of the direct current method is limited and it is easily affected by the resistivity of borehole mud; the transient electromagnetic method is a time-domain electromagnetic exploration method. It uses an ungrounded loop or a grounded wire source to emit a primary pulse magnetic field into the ground, and during the interval of the primary pulse magnetic field, a coil or a grounded electrode is used to observe the secondary induced eddy current field in the underground medium, thereby detecting the resistivity of the medium. The transient electromagnetic method has a strong response to highly conductive geological bodies, but has low shallow-layer resolution and is severely affected by electromagnetic interference from underground metal equipment.

[0003] Both the direct current method and the transient electromagnetic method have their defects, resulting in blurred boundaries of abnormal bodies and high misjudgment rates in geological exploration. Therefore, a solution that can accurately detect the boundaries of geological abnormal bodies is needed. Summary of the Invention

[0004] In order to solve the above technical problems, this application is proposed. Embodiments of this application provide a borehole geological geophysical exploration method and system based on the coupling of direct current method - transient electromagnetic method.

[0005] According to one aspect of this application, there is provided a borehole geological geophysical exploration method based on the coupling of direct current method - transient electromagnetic method, including: collecting resistance information of a target area using the direct current method; collecting the secondary field attenuation signal of the target area using the transient electromagnetic method; coupling the resistance information and the secondary field attenuation signal of the target area to comprehensively obtain the detection result of the target area.

[0006] In one embodiment, the collecting resistance information of a target area using the direct current method includes: arranging a circular electrode pair along the axial direction of the drill collar and using a constant current source to excite a stable current field to measure the resistance information of the target area.

[0007] In one embodiment, the measuring the resistance information of the target area includes: measuring the conductivity and potential of the target area; calculating the resistance information of the target area based on the conductivity and potential of the target area using the finite element method or the finite difference method.

[0008] In one embodiment, the step of collecting the secondary field attenuation signal of the target area by using the transient electromagnetic method includes: arranging an integrated transmitting coil array and a receiving magnetic rod along the axial direction of the drill collar, controlling the transmitting coil array to emit a pulsed magnetic field, and using the receiving magnetic rod to receive the secondary field attenuation signal of the target area.

[0009] In one embodiment, the method for borehole geophysical prospecting based on the coupling of direct current method and transient electromagnetic method further includes: isolating the annular electrode pair, the integrated transmitting coil array and the receiving magnetic rod by using a magnetic shielding cover.

[0010] In one embodiment, the step of coupling the resistance information and the secondary field attenuation signal of the target area and comprehensively obtaining the detection result of the target area includes: inputting the resistance information and the secondary field attenuation signal of the target area into a detection model to obtain the detection result of the target area.

[0011] In one embodiment, the step of inputting the resistance information and the secondary field attenuation signal of the target area into a detection model to obtain the detection result of the target area includes: performing weighted fusion on the resistance information and the secondary field attenuation signal of the target area to obtain the detection result of the target area; wherein, the weight of the resistance information of the target area is inversely correlated with the detection depth, and the weight of the secondary field attenuation signal of the target area is positively correlated with the detection depth.

[0012] In one embodiment, the method for borehole geophysical prospecting based on the coupling of direct current method and transient electromagnetic method further includes: constructing a loss function of the detection model based on the measured resistance information and the corresponding estimated resistance information of the standard area, and the measured secondary field attenuation signal and the corresponding estimated secondary field attenuation signal of the standard area; using a genetic algorithm to solve the minimum value of the loss function of the detection model to obtain the weights of the resistance information and the secondary field attenuation signal corresponding to different detection depths.

[0013] In one embodiment, the step of coupling the resistance information and the secondary field attenuation signal of the target area and comprehensively obtaining the detection result of the target area includes: if the resistivity of the target area is less than a preset resistivity threshold and the secondary field attenuation rate of the target area is greater than a preset attenuation rate threshold, determining that the target area is a high-risk water-conducting channel.

[0014] According to another aspect of the present application, there is provided a borehole geophysical prospecting system based on the coupling of direct current method and transient electromagnetic method, including: a direct current method acquisition module for acquiring the resistance information of a target area by using the direct current method; a transient electromagnetic method acquisition module for acquiring the secondary field attenuation signal of the target area by using the transient electromagnetic method; and a detection result coupling module for coupling the resistance information and the secondary field attenuation signal of the target area and comprehensively obtaining the detection result of the target area.

[0015] According to another aspect of the present application, there is provided a computer-readable storage medium storing a computer program for executing any one of the above methods.

[0016] According to another aspect of the present application, there is provided an electronic device, including: a processor; a memory for storing executable instructions of the processor; the processor is configured to execute any one of the above methods.

[0017] The method and system for borehole geophysical prospecting based on the coupling of direct current method and transient electromagnetic method provided by the present application collect the resistance information of the target area by using the direct current method; collect the secondary field attenuation signal of the target area by using the transient electromagnetic method; couple the resistance information and the secondary field attenuation signal of the target area to comprehensively obtain the detection result of the target area; the present application simultaneously uses the direct current method and the transient electromagnetic method to collect relevant information of the target area, and couples the resistance information and the secondary field attenuation signal of the target area to combine the advantages of both and improve the accuracy of geological exploration. Description of the Drawings

[0018] By describing the embodiments of the present application in more detail in conjunction with the drawings, the above and other objects, features, and advantages of the present application will become more obvious. The drawings are used to provide a further understanding of the embodiments of the present application, and constitute a part of the specification, and are used to explain the present application together with the embodiments of the present application, and do not constitute a limitation to the present application. In the drawings, the same reference numerals generally represent the same components or steps.

[0019] Figure 1 is a schematic flow chart of a method for borehole geophysical prospecting based on the coupling of direct current method and transient electromagnetic method provided by an exemplary embodiment of the present application.

[0020] Figure 2 is a schematic structural diagram of a system for borehole geophysical prospecting based on the coupling of direct current method and transient electromagnetic method provided by an exemplary embodiment of the present application.

[0021] Figure 3 is a structural diagram of an electronic device provided by an exemplary embodiment of the present application. Detailed Description of the Embodiments

[0022] Next, exemplary embodiments according to the present application will be described in detail with reference to the drawings. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. It should be understood that the present application is not limited by the exemplary embodiments described herein.

[0023] Figure 1 is a schematic flow chart of a method for borehole geophysical prospecting based on the coupling of direct current method and transient electromagnetic method provided by an exemplary embodiment of the present application. As Figure 1As shown in the figure, the borehole geological geophysical exploration method based on the coupling of DC resistivity method and transient electromagnetic method includes the following steps:

[0024] Step 110: Collect the resistance information of the target area using the DC resistivity method.

[0025] In this application, inclined boreholes (for example, with an inclination angle of 30°) are constructed in the suspected water-conducting channel area (i.e., the target area), and a composite sensor array is installed in the boreholes to collect the resistance information of the target area using the DC resistivity method. Specifically, the acquisition frequency of the DC resistivity method is 10 Hz.

[0026] Step 120: Collect the secondary field attenuation signal of the target area using the transient electromagnetic method.

[0027] In this application, the transient electromagnetic method is also used to collect the secondary field attenuation signal of the target area. Specifically, the transient electromagnetic method emits a pulsed magnetic field with a pulse width of 1 ms and receives the secondary field signal with a delay time of 0.1 - 20 ms.

[0028] Step 130: Couple the resistance information and the secondary field attenuation signal of the target area to comprehensively obtain the detection result of the target area.

[0029] After this application separately uses the DC resistivity method and the transient electromagnetic method to collect the resistance information and the secondary field attenuation signal of the target area, by coupling the two types of data, the detection result of the target area is comprehensively determined to improve the detection accuracy.

[0030] The borehole geological geophysical exploration method based on the coupling of DC resistivity method and transient electromagnetic method provided by this application collects the resistance information of the target area using the DC resistivity method; collects the secondary field attenuation signal of the target area using the transient electromagnetic method; couples the resistance information and the secondary field attenuation signal of the target area to comprehensively obtain the detection result of the target area; this application simultaneously uses the DC resistivity method and the transient electromagnetic method to collect relevant information of the target area, and couples the resistance information and the secondary field attenuation signal of the target area to integrate the advantages of both and improve the accuracy of geological exploration.

[0031] In one embodiment, the specific implementation manner of the above step 110 can be: arranging a pair of annular electrodes along the axial direction of the drill collar and using a constant current source to excite a stable current field to measure the resistance information of the target area.

[0032] This application arranges a pair of annular electrodes along the axial direction of the drill collar and uses a constant current source to excite a stable current field to collect the resistance information of the target area, thereby collecting the resistance information of the target area using the DC resistivity method.

[0033] In one embodiment, the specific implementation manner of the above step 110 can be: measuring the conductivity and potential of the target area; based on the conductivity and potential of the target area, calculating the resistance information of the target area using the finite element method or the finite difference method.

[0034] This application measures the conductivity and potential of the target area, and solves the DC electric field equation by the finite element method or the finite difference method to obtain the potential gradient or apparent resistivity of the target area. Among them, the DC electric field equation is , represents the divergence calculation, is the conductivity, is the potential. The unit of the potential gradient is mV / m, and the unit of the apparent resistivity is Ω·m.

[0035] In one embodiment, the specific implementation manner of the above step 120 may be: arranging an integrated transmitting coil array and a receiving magnetic rod along the axial direction of the drill collar, controlling the transmitting coil array to emit a pulsed magnetic field, and using the receiving magnetic rod to receive the secondary field attenuation signal of the target area.

[0036] This application arranges an integrated transmitting coil array and a receiving magnetic rod along the axial direction of the drill collar, controls the transmitting coil array to emit a pulsed magnetic field, and uses the receiving magnetic rod to receive the secondary field attenuation signal of the target area. Specifically, this application solves the Maxwell equations and calculates the attenuation curve of the transient electromagnetic field of the target area in combination with the formation conductivity distribution.

[0037] In one embodiment, the above-mentioned geological geophysical exploration method in the borehole based on the coupling of DC resistivity method and transient electromagnetic method may further include: using a magnetic shielding cover to isolate the annular electrode pair, the integrated transmitting coil array and the receiving magnetic rod.

[0038] This application uses a magnetic shielding cover to isolate the metal components of the detection system to exclude external interference and further improve the detection accuracy.

[0039] In one embodiment, the specific implementation manner of the above step 130 may be: inputting the resistance information and the secondary field attenuation signal of the target area into the detection model to obtain the detection result of the target area.

[0040] This application inputs the measured resistance information and secondary field attenuation signal of the target area into the detection model, and comprehensively obtains the detection result of the target area by combining the measurement results of the DC resistivity method and the transient electromagnetic method. It should be understood that the detection model in this application may be a comprehensive model, that is, the resistance information and the secondary field attenuation signal are used as inputs simultaneously to comprehensively obtain the detection result of the target area; the detection model may also be two models, and the two models respectively obtain the detection result of the target area based on the resistance information and the secondary field attenuation signal, and then fuse the two detection results to obtain the final detection result.

[0041] In one embodiment, the specific implementation of the above step 130 may be: weighted fusion of the resistance information and the secondary field attenuation signal of the target area to obtain the detection result of the target area; wherein, the weight of the resistance information of the target area is inversely correlated with the detection depth, and the weight of the secondary field attenuation signal of the target area is positively correlated with the detection depth.

[0042] Based on the advantages and disadvantages of the direct current method and the transient electromagnetic method, this application adjusts the weights of the resistance information and the secondary field attenuation signal for detections at different depths to ensure the detection accuracy. For example, this application can set that when the detection depth is less than 50 meters, the resistance information is the main and the secondary field attenuation signal is the auxiliary, that is, the weight of the resistance information is greater than the weight of the secondary field attenuation signal, and when the detection depth is greater than 50 meters, the secondary field attenuation signal is the main and the resistance information is the auxiliary, that is, the weight of the resistance information is less than the weight of the secondary field attenuation signal, wherein, the sum of the weight of the resistance information and the weight of the secondary field attenuation signal is equal to 1.

[0043] In one embodiment, the above direct current method - transient electromagnetic method coupled borehole geophysical prospecting method may further include: constructing a loss function of the detection model based on the measured resistance information and the corresponding estimated resistance information of the standard area, and the measured secondary field attenuation signal and the corresponding estimated secondary field attenuation signal of the standard area; using the genetic algorithm to solve the minimum value of the loss function of the detection model to obtain the weights of the resistance information and the secondary field attenuation signal corresponding to different detection depths.

[0044] This application can set the weights of the resistance information and the secondary field attenuation signal at different detection depths according to empirical values. This application can also dynamically adjust the weights of the resistance information and the secondary field attenuation signal at different detection depths specifically for different target areas. For example, this application can measure the measured resistance information and the measured secondary field attenuation signal in the standard area (i.e., the selected test area) within the target area, and construct a loss function of the detection model in combination with the corresponding estimated resistance information and the corresponding estimated secondary field attenuation signal in this standard area, and use the genetic algorithm to solve the minimum value of the loss function of the detection model to obtain the weights of the resistance information and the secondary field attenuation signal corresponding to different detection depths. Specifically, the loss function constructed by this application is:

[0045] ;

[0046] The corresponding objective function is:

[0047] ;

[0048] wherein, J DC is the forward response matrix (estimated resistance information) of the direct current method, representing the potential gradient or apparent resistivity calculated according to the current electrical model, dDC is the actual observed data of the direct current resistivity method (i.e., measuring resistance information), J TEM is the forward response matrix of the transient electromagnetic method (estimating the secondary field attenuation signal), representing the secondary field attenuation signal calculated according to the current electrical property model, d TEM is the actual observed data of the transient electromagnetic method (i.e., measuring the secondary field attenuation signal), and are the weights of the resistance information and the weights of the secondary field attenuation signal respectively.

[0049] This application obtains the weights of the resistance information and the weights of the secondary field attenuation signal at different depths by solving the above objective function.

[0050] In one embodiment, the specific implementation manner of the above step 130 may be: if the resistivity of the target area is less than the preset resistivity threshold and the secondary field attenuation rate of the target area is greater than the preset attenuation rate threshold, then determine that the target area is a high-risk water-conducting channel.

[0051] After this application measures and calculates the resistivity and secondary field attenuation rate of the target area, it determines whether the target area is a water-conducting channel area according to the resistivity and secondary field attenuation rate. Specifically, this application sets a resistivity threshold and an attenuation rate threshold. For example, the resistivity threshold is 10 Ω·m and the attenuation rate threshold is 5 mV / ms. If the resistivity of the target area is less than the resistivity threshold and the secondary field attenuation rate of the target area is greater than the attenuation rate threshold, then determine that the target area is a high-risk water-conducting channel. And when the high-risk water-conducting channel is determined, an audible and visual alarm device can be activated to prompt relevant staff.

[0052] This application can also fuse the results obtained by the direct current resistivity method and the transient electromagnetic method respectively to generate a three-dimensional electrical anomaly body distribution map, so as to more intuitively display the distribution of the water-conducting channels in the target area.

[0053] Figure 2 is a schematic structural diagram of a borehole geological geophysical exploration system based on the coupling of the direct current resistivity method and the transient electromagnetic method provided by an exemplary embodiment of this application. As Figure 2 shown, the borehole geological geophysical exploration system 20 based on the coupling of the direct current resistivity method and the transient electromagnetic method includes: a direct current resistivity method acquisition module 21 for acquiring the resistance information of the target area by using the direct current resistivity method; a transient electromagnetic method acquisition module 22 for acquiring the secondary field attenuation signal of the target area by using the transient electromagnetic method; a detection result coupling module 23 for coupling the resistance information and the secondary field attenuation signal of the target area to comprehensively obtain the detection result of the target area.

[0054] The borehole geological geophysical exploration system based on the coupling of direct current method and transient electromagnetic method provided by this application uses the direct current method acquisition module 21 to acquire the resistance information of the target area by the direct current method; the transient electromagnetic method acquisition module 22 uses the transient electromagnetic method to acquire the secondary field attenuation signal of the target area; the detection result coupling module 23 couples the resistance information and the secondary field attenuation signal of the target area to comprehensively obtain the detection result of the target area; this application simultaneously uses the direct current method and the transient electromagnetic method to acquire relevant information of the target area, and couples the resistance information and the secondary field attenuation signal of the target area to integrate the advantages of both and improve the accuracy of geological exploration.

[0055] In one embodiment, the above-mentioned direct current method acquisition module 21 can be further configured to: arrange annular electrode pairs along the axial direction of the drill collar, and use a constant current source to excite a stable current field to measure the resistance information of the target area.

[0056] In one embodiment, the above-mentioned direct current method acquisition module 21 can be further configured to: measure the conductivity and potential of the target area; based on the conductivity and potential of the target area, use the finite element method or the finite difference method to calculate the resistance information of the target area.

[0057] In one embodiment, the above-mentioned transient electromagnetic method acquisition module 22 can be further configured to: arrange an integrated transmitting coil array and a receiving magnetic rod along the axial direction of the drill collar, control the transmitting coil array to emit a pulsed magnetic field, and use the receiving magnetic rod to receive the secondary field attenuation signal of the target area.

[0058] In one embodiment, the above-mentioned borehole geological geophysical exploration system 20 based on the coupling of direct current method and transient electromagnetic method can be further configured to: use a magnetic shielding cover to isolate the annular electrode pair, the integrated transmitting coil array and the receiving magnetic rod.

[0059] In one embodiment, the above-mentioned detection result coupling module 23 can be further configured to: input the resistance information and the secondary field attenuation signal of the target area into a detection model to obtain the detection result of the target area.

[0060] In one embodiment, the above-mentioned detection result coupling module 23 can be further configured to: perform weighted fusion on the resistance information and the secondary field attenuation signal of the target area to obtain the detection result of the target area; wherein, the weight of the resistance information of the target area is inversely correlated with the detection depth, and the weight of the secondary field attenuation signal of the target area is positively correlated with the detection depth.

[0061] In one embodiment, the above-mentioned borehole geological geophysical exploration system 20 based on the coupling of direct current resistivity method and transient electromagnetic method can be further configured to: construct a loss function of the detection model based on the measured resistance information and the corresponding estimated resistance information of the standard area, and the measured secondary field attenuation signal and the corresponding estimated secondary field attenuation signal of the standard area; use the genetic algorithm to solve the minimum value of the loss function of the detection model to obtain the weights of the resistance information and the weights of the secondary field attenuation signal corresponding to different detection depths.

[0062] In one embodiment, the above-mentioned detection result coupling module 23 can be further configured to: if the resistivity of the target area is less than a preset resistivity threshold and the secondary field attenuation rate of the target area is greater than a preset attenuation rate threshold, determine that the target area is a high-risk water-conducting channel.

[0063] Next, refer to Figure 3 to describe the electronic device according to the embodiments of the present application. The electronic device can be any one or both of the first device and the second device, or a stand-alone device independent of them, and the stand-alone device can communicate with the first device and the second device to receive the input signals collected from them.

[0064] Figure 3 The block diagram of the electronic device according to the embodiments of the present application is illustrated.

[0065] As Figure 3 shown, the electronic device 10 includes one or more processors 11 and a memory 12.

[0066] The processor 11 can be a central processing unit (CPU) or other forms of processing units with data processing capabilities and / or instruction execution capabilities, and can control other components in the electronic device 10 to perform desired functions.

[0067] The memory 12 can include one or more computer program products, and the computer program products can include various forms of computer-readable storage media, such as volatile memory and / or non-volatile memory. The volatile memory can include, for example, random access memory (RAM) and / or cache memory, etc. The non-volatile memory can include, for example, read-only memory (ROM), hard disk, flash memory, etc. One or more computer program instructions can be stored on the computer-readable storage medium, and the processor 11 can run the program instructions to implement the methods of the various embodiments of the present application described above and / or other desired functions. Various contents such as input signals, signal components, and noise components can also be stored in the computer-readable storage medium.

[0068] In one example, the electronic device 10 may further include: an input device 13 and an output device 14, and these components are interconnected through a bus system and / or other forms of connection mechanisms (not shown).

[0069] When the electronic device is a stand-alone device, the input device 13 may be a communication network connector for receiving the collected input signals from the first device and the second device.

[0070] In addition, the input device 13 may further include, for example, a keyboard, a mouse, and the like.

[0071] The output device 14 may output various information to the outside, including the determined distance information, direction information, etc. The output device 14 may include, for example, a display, a speaker, a printer, and a communication network and its connected remote output devices, and the like.

[0072] Of course, for simplicity, Figure 3 only some of the components related to the present application in the electronic device 10 are shown, and components such as a bus, an input / output interface, and the like are omitted. In addition, according to specific application scenarios, the electronic device 10 may further include any other appropriate components.

[0073] In addition to the above methods and devices, an embodiment of the present application may also be a computer program product, which includes computer program instructions, and when the computer program instructions are run by a processor, the processor is caused to execute the steps in the methods according to various embodiments of the present application described in the above "Exemplary Method" section of this specification.

[0074] The computer program product may be written in any combination of one or more programming languages for programming code to perform the operations of the embodiments of the present application. The programming languages include object-oriented programming languages, such as Java, C++, etc., and also include conventional procedural programming languages, such as the "C" language or similar programming languages. The program code may be executed entirely on the user computing device, partially on the user device, executed as an independent software package, partially on the user computing device and partially on a remote computing device, or entirely on a remote computing device or server.

[0075] In addition, an embodiment of the present application may also be a computer-readable storage medium, on which computer program instructions are stored, and when the computer program instructions are run by a processor, the processor is caused to execute the steps in the methods according to various embodiments of the present application described in the above "Exemplary Method" section of this specification.

[0076] The computer-readable storage medium may adopt any combination of one or more readable media. The readable media may be a readable signal medium or a readable storage medium. The readable storage medium may include, for example, but is not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination of the above. More specific examples (a non-exhaustive list) of the readable storage medium include: an electrical connection with one or more wires, a portable disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above.

[0077] The basic principles of the present application have been described above in conjunction with specific embodiments. However, it should be noted that the advantages, benefits, effects, etc. mentioned in the present application are only examples and not limitations, and it cannot be considered that these advantages, benefits, effects, etc. are essential for each embodiment of the present application. In addition, the above-disclosed specific details are only for illustrative and easy-to-understand purposes and are not limitations. The above details do not limit the present application to necessarily adopt the above specific details for implementation.

[0078] The block diagrams of the devices, apparatuses, equipment, and systems involved in the present application are only illustrative examples and do not intend to require or imply that they must be connected, arranged, and configured in the manner shown in the block diagrams. As those skilled in the art will recognize, these devices, apparatuses, equipment, and systems can be connected, arranged, and configured in any manner. Words such as "including", "comprising", "having", etc. are open-ended words, meaning "including but not limited to", and can be used interchangeably with each other. The word "or" and "and" used herein refer to the word "and / or" and can be used interchangeably with each other, unless the context clearly indicates otherwise. The word "such as" used herein refers to the phrase "such as but not limited to" and can be used interchangeably with each other.

[0079] It should also be noted that in the devices, equipment, and methods of the present application, each component or each step can be decomposed and / or recombined. These decompositions and / or recombinations should be regarded as equivalent solutions of the present application.

[0080] The above description of the disclosed aspects enables any person skilled in the art to make or use the present application. Various modifications to these aspects are very obvious to those skilled in the art, and the general principles defined herein can be applied to other aspects without departing from the scope of the present application. Therefore, the present application is not intended to be limited to the aspects shown herein, but rather to the broadest scope consistent with the principles and novel features disclosed herein.

[0081] The foregoing description has been presented for purposes of illustration and description. In addition, this description is not intended to limit embodiments of the present application to the forms disclosed herein. Although several example aspects and embodiments have been discussed above, those skilled in the art will recognize some variations, modifications, alterations, additions, and subcombinations thereof.

Claims

1. A method for in-hole geological exploration based on direct current method-transient electromagnetic method coupling, characterized in that: include: The resistance information of the target area is collected by using the direct current method; Using transient electromagnetic method to collect secondary field attenuation signal of the target area; The resistance information of the target area and the secondary field attenuation signal are coupled to comprehensively obtain the detection result of the target area.

2. The method for in-hole geological exploration based on direct current method-transient electromagnetic method coupling according to claim 1 is characterized in that: The method of collecting the resistance information of the target area by using the direct current method includes: A pair of annular electrodes are arranged along the axial direction of the drill collar, and a constant current source is used to excite a stable current field to measure the resistance information of the target area.

3. The method for in-hole geological exploration based on direct current method-transient electromagnetic method coupling according to claim 2 is characterized in that: The measuring the resistance information of the target area comprises: measuring the conductivity and potential of the target area; Based on the conductivity and potential of the target area, the resistance information of the target area is calculated by using a finite element method or a finite difference method.

4. The method for in-hole geological exploration based on direct current method-transient electromagnetic method coupling according to claim 2 is characterized in that: The method of collecting the secondary field attenuation signal of the target area by using the transient electromagnetic method comprises: An integrated transmitting coil array and a receiving magnetic rod are arranged along the axial direction of the drill collar, the transmitting coil array is controlled to transmit a pulsed magnetic field, and the receiving magnetic rod is used to receive a secondary field attenuation signal of the target area.

5. The method for in-hole geological exploration based on direct current method-transient electromagnetic method coupling according to claim 4 is characterized in that: The in-hole geological geophysical exploration method based on direct current method-transient electromagnetic method coupling also includes: A magnetic shield is used to isolate the annular electrode pair, the integrated transmitting coil array and the receiving magnetic rod.

6. The method for in-hole geological exploration based on direct current method-transient electromagnetic method coupling according to claim 1 is characterized in that: The coupling of the resistance information of the target area and the secondary field attenuation signal to comprehensively obtain the detection result of the target area includes: The resistance information and the secondary field attenuation signal of the target area are input into a detection model to obtain a detection result of the target area.

7. The method for in-hole geological exploration based on direct current method-transient electromagnetic method coupling according to claim 6 is characterized in that: Inputting the resistance information and the secondary field attenuation signal of the target area into the detection model to obtain the detection result of the target area includes: The resistance information and the secondary field attenuation signal of the target area are weighted and fused to obtain the detection result of the target area; wherein the weight of the resistance information of the target area is negatively correlated with the detection depth, and the weight of the secondary field attenuation signal of the target area is positively correlated with the detection depth.

8. The method for in-hole geological exploration based on direct current method-transient electromagnetic method coupling according to claim 7 is characterized in that: The in-hole geological geophysical exploration method based on direct current method-transient electromagnetic method coupling also includes: Constructing a loss function of the detection model based on measured resistance information and corresponding estimated resistance information of a standard area, a measured secondary field attenuation signal of the standard area and a corresponding estimated secondary field attenuation signal; A genetic algorithm is used to solve the minimum value of the loss function of the detection model to obtain the weights of the resistance information and the weights of the secondary field attenuation signal corresponding to different detection depths.

9. The method for in-hole geological exploration based on direct current method-transient electromagnetic method coupling according to claim 1 is characterized in that: The coupling of the resistance information of the target area and the secondary field attenuation signal to comprehensively obtain the detection result of the target area includes: If the resistivity of the target area is less than a preset resistivity threshold, and the secondary field attenuation rate of the target area is greater than a preset attenuation rate threshold, the target area is determined to be a high-risk water channel.

10. Based on the direct current method-transient electromagnetic method coupling borehole geological geophysical exploration system, it is characterized by: include: A direct current electrical method acquisition module is used to acquire resistance information of a target area using a direct current electrical method; A transient electromagnetic method acquisition module, used for acquiring a secondary field attenuation signal of the target area by using a transient electromagnetic method; The detection result coupling module is used to couple the resistance information of the target area and the secondary field attenuation signal to comprehensively obtain the detection result of the target area.

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