Combined acquisition device for ocean induced polarization and spontaneous potential and data processing method

Abstract

This invention discloses a combined ocean induced polarization and spontaneous potential data collection device and data processing method, addressing the existing technical problem of being unable to accurately characterize sulfide ore morphology. The device comprises a first autonomous underwater robot and a second autonomous underwater robot, the first robot being equipped with an induced polarization transmitter, and the second robot being equipped with a spontaneous potential collection device. The induced polarization transmitter comprises an induced polarization control chamber, a first watertight cable, a positive transmitting terminal electrode, and a negative transmitting terminal electrode, while the spontaneous potential collection device comprises a spontaneous potential collection chamber, a second watertight cable, and several pairs of Ag / AgCl non-polarizable electrodes. This invention can more accurately interpret the distribution characteristics of seafloor sulfides, reduce ambiguity, and improve exploration accuracy and reliability.

Description

Technical Field

[0001] The present invention belongs to the field of marine geophysics, and in particular relates to a device for jointly collecting ocean induced polarization and spontaneous potential and a data processing method. Background Art

[0002] Seabed polymetallic sulfides are rich in metals such as copper, zinc, silver, and gold, and are considered to be one of the three major potential marine mineral resources. Indoor rock electrical measurement data show that sulfides have an extremely strong induced polarization effect, which will distort the currently popular active source electromagnetic exploration data based on resistivity, and the inverted resistivity cannot accurately characterize the morphology of sulfide ores. In addition, the natural potential inversion based on resistivity constraints will also result in erroneous interpretation results. Therefore, it is urgent to carry out marine induced polarization exploration based on DC resistivity. At the same time, the development of a joint inversion algorithm for multiple geophysical data can further reduce the multi-solution problem. Both the induced polarization method and the natural potential method data are obtained based on the potential difference data between non-polarized electrodes, and traditional towed measurements cannot guarantee the stability of the electrodes. Therefore, the present invention proposes a joint acquisition device and data processing method for induced polarization and natural potential data carried by an underwater autonomous robot. Summary of the Invention

[0003] The purpose of the present invention is to provide a combined ocean induced polarization and spontaneous potential acquisition device and data processing method to solve the technical problem in the prior art that the morphology of sulfide minerals cannot be accurately characterized.

[0004] To achieve the above objectives, the present invention provides the following technical solutions:

[0005] In a first aspect, the present invention provides a combined ocean induced polarization and spontaneous potential acquisition device, comprising a first underwater autonomous robot and a second underwater autonomous robot, wherein the first underwater autonomous robot is equipped with an induced polarization transmitting device, and the second underwater autonomous robot is equipped with a spontaneous potential acquisition device;

[0006] The induced polarization transmitting device includes an induced polarization control chamber, a first watertight cable, a transmitting end positive electrode, and a transmitting end negative electrode. The induced polarization control chamber is fixed to the housing of the first underwater autonomous robot, the first watertight cable is installed at the end of the first underwater autonomous robot, the transmitting end positive electrode is installed at the tail of the first underwater autonomous robot, and the transmitting end negative electrode is fixed to the first watertight cable. A transmitting electric field is formed between the transmitting end positive electrode and the transmitting end negative electrode.

[0007] The spontaneous potential acquisition device includes a spontaneous potential acquisition chamber, a second watertight cable and several pairs of Ag / AgCl non-polarizable electrodes. The spontaneous potential acquisition chamber is fixed to the outer shell of the second underwater autonomous robot, the second watertight cable is installed at the end of the second underwater autonomous robot, and the Ag / AgCl non-polarizable electrodes are distributed at the tail of the second underwater autonomous robot and on the second watertight cable to collect mixed data of induced polarization and spontaneous potential.

[0008] Furthermore, it also includes several buoyancy balls, which have grooves in the center and are distributed on the first watertight cable and the second watertight cable in sequence to maintain upward buoyancy and ensure the safe operation of the first underwater autonomous robot and the second underwater autonomous robot.

[0009] Furthermore, it also includes a scientific research vessel, which is equipped with an ultra-short baseline receiving device, and the underwater autonomous robot is equipped with an ultra-short baseline transmitting device. Through the cooperation of the transmitting and receiving devices, the position of the underwater robot and the distance between the underwater autonomous robots can be located in real time.

[0010] Furthermore, the distance between the first underwater autonomous robot and the second underwater autonomous robot is 100 meters, the distance between the positive pole of the transmitting end and the negative pole of the transmitting end is 15 meters, the transmitting waveform is a bipolar square wave, the transmitting period is 2S, and it is transmitted once every 10 seconds.

[0011] Furthermore, the distance between two adjacent Ag / AgCl non-polarized electrodes is 15 meters, and the receiving frequency of the Ag / AgCl non-polarized electrode at the receiving end is set to 250 Hz-1000 Hz.

[0012] Furthermore, an altimeter is installed on the bottom of the underwater autonomous robot to control the height from the seabed. During the collection process, the underwater autonomous robot is controlled to be 15 meters away from the seabed and the speed is controlled at 0.5 m / s.

[0013] In a second aspect, the present invention provides a data processing method for jointly collecting ocean induced polarization and spontaneous potential, comprising:

[0014] Collect mixed data of induced polarization and spontaneous potential using equipment carried by an underwater autonomous robot;

[0015] Resampling is used to obtain spontaneous potential data, which is then re-interpolated to the acquisition frequency. The interpolated data is then subtracted from the original data to obtain induced polarization data, achieving a preliminary separation of the two data types.

[0016] The two types of data after preliminary separation are subjected to denoising respectively to improve data quality;

[0017] The denoised data were jointly inverted using a joint inversion method based on cross-gradient structure constraints to obtain a detailed distribution image of seabed sulfides.

[0018] Furthermore, the target functional of the joint inversion of the three-dimensional natural potential constrained by the cross-gradient structure and the induced polarization method is as follows:

[0019]

[0020] The superscripts sp and ip represent the spontaneous potential and induced polarization data, respectively. is the data weighting matrix, is the predicted data in the inversion, is the observed data after denoising, is the regularization factor, which is used to control the weight of the model constraint. is the model weight matrix, are the model parameters obtained by inversion, is the reference model, is a constant coefficient, which is used to control the weight of the cross term in the joint inversion;

[0021] The following iterative equations for model changes are obtained by linearized least squares inversion:

[0022]

[0023] in, , , , , , , .

[0024] Based on the above technical solution, the embodiments of the present invention can produce at least the following technical effects:

[0025] (1) The present invention provides a combined ocean induced polarization and natural potential acquisition device. The present invention implements two autonomous underwater robots (AUVs) equipped with induced polarization and natural potential equipment, which can realize the simultaneous acquisition of two types of data. Moreover, since the robots have stable motion characteristics, the stability of the electrodes is guaranteed, thereby improving the accuracy of data acquisition. By optimizing the electrode mounting position and acquisition parameters, detection at different depths is achieved, thereby improving exploration efficiency. The mid-ocean ridge sulfides are located under the sea water at a depth of about 1500 meters to 3000 meters, with complex terrain and large ocean currents. The underwater autonomous robot used in the present invention has strong environmental adaptability and can work stably in complex environments, ensuring the continuity and integrity of data acquisition.

[0026] (2) Data processing method for joint acquisition of ocean induced polarization and natural potential. By developing a separation and joint inversion algorithm for induced polarization data and natural potential data, the present invention can more accurately interpret the distribution characteristics of seabed sulfides, reduce ambiguity, and improve the accuracy and reliability of exploration. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0028] Figure 1 Schematic diagram of the AUV-based induced polarization device and spontaneous potential device of the present invention;

[0029] Figure 2 It is a schematic structural diagram of the first underwater autonomous robot of the present invention;

[0030] Figure 3 is a schematic structural diagram of a second underwater autonomous robot of the present invention;

[0031] Figure 4 Schematic diagram of the detection depth of the induced polarization equipment of the present invention;

[0032] Figure 5 It is a data processing flow chart of the present invention.

[0033] In the figure: 1. First underwater autonomous robot; 2. Second underwater autonomous robot; 3. Induced polarization control chamber; 4. First watertight cable; 5. Transmitter positive electrode; 6. Transmitter negative electrode; 7. Transmitting electric field; 8. Natural potential acquisition chamber; 9. Second watertight cable; 10. Ag / AgCl non-polarizable electrode; 11. Buoyancy ball; 12. Research vessel; 13. Seabed; 14. Stern main thruster; 15. Bow auxiliary thruster; 16. Bow horizontal rudder; 17. Stern horizontal rudder; 18. Forward-looking sonar; 19. Temperature, salinity and depth sensor; 20. Vertical stabilizer fin; 21. Long baseline; 22. Acoustic communication transducer. DETAILED DESCRIPTION

[0034] The technical solutions in the embodiments of the present invention will be described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in this field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0035] This embodiment provides a combined ocean induced polarization and spontaneous potential acquisition device and data processing method. Figure 1-5 Describe them together.

[0036] Example 1

[0037] See also Figure 1-Figure 3 , a combined ocean induced polarization and natural potential acquisition device, comprising a first underwater autonomous robot 1 and a second underwater autonomous robot 2, wherein the first underwater autonomous robot 1 is equipped with an induced polarization transmitting device, and the second underwater autonomous robot 2 is equipped with a natural potential acquisition device;

[0038] The induced polarization transmitting device includes an induced polarization control chamber 3, a first watertight cable 4, a transmitting end positive electrode 5 and a transmitting end negative electrode 6. The induced polarization control chamber 3 is fixed to the shell of the first underwater autonomous robot 1, the first watertight cable 4 is installed at the end of the first underwater autonomous robot 1, the transmitting end positive electrode 5 is installed at the tail of the first underwater autonomous robot 1, and the transmitting end negative electrode 6 is fixed to the first watertight cable 4. A transmitting electric field 7 is formed between the transmitting end positive electrode 5 and the transmitting end negative electrode 6.

[0039] The spontaneous potential collection equipment includes a spontaneous potential collection chamber 8, a second watertight cable 9 and several pairs of Ag / AgCl non-polarizable electrodes 10. The spontaneous potential collection chamber 8 is fixed to the outer shell of the second underwater autonomous robot 2, the second watertight cable 9 is installed at the end of the second underwater autonomous robot 2, and the Ag / AgCl non-polarizable electrodes 10 are distributed at the tail of the second underwater autonomous robot 2 and on the second watertight cable 9, and are used to collect mixed data of induced polarization and spontaneous potential.

[0040] In this embodiment, several buoyancy balls 11 are also included. The buoyancy balls 11 have a groove in the center and are distributed in sequence on the first watertight cable 4 and the second watertight cable 9 to maintain upward buoyancy and ensure the safe operation of the first underwater autonomous robot 1 and the second underwater autonomous robot 2.

[0041] In this embodiment, a scientific research vessel 12 is also included. The scientific research vessel 12 is equipped with an ultra-short baseline receiving device, and the underwater autonomous robot is equipped with an ultra-short baseline transmitting device. Through the cooperation of the transmitting and receiving devices, the position of the underwater robot and the distance between the underwater autonomous robots can be located in real time.

[0042] In this embodiment, the first underwater autonomous robot 1 and the second underwater autonomous robot 2 both include a robot shell made of buoyant material, a stern main thruster 14 and a bow auxiliary thruster 15 for driving the underwater autonomous robot forward, a bow horizontal rudder 16 and a stern horizontal rudder 17 for controlling the posture and heading of the underwater autonomous robot, a forward-looking sonar 18 for detecting obstacles ahead and underwater terrain, an internal temperature, salinity and depth sensor 19, a vertical stabilizer 20, a long baseline 21 for positioning and navigation, and an acoustic communication transducer 22 arranged on the upper part of the robot shell.

[0043] In order to improve the stability and accuracy of the acquisition device, this embodiment adjusts the various parameters of the underwater autonomous robot. Figure 4 The effective detection depth o" of the induced polarization method is approximately one-third of the distance between the midpoint o of the transmitting end positive electrode 12 and the transmitting end negative electrode 13 and the midpoint o' of the Ag / AgCl non-polarized electrode 16. Once the distance L between the two AUVs is determined, a single excitation of the induced polarization transmitting end can obtain data at three different depths (L / 3, L / 3+7.5, and L / 3+15). The sulfide ore bodies currently being investigated on the mid-ocean ridge are distributed within 100 meters of the seabed, so the distance between the two AUVs should be maintained at 300 meters. Considering the attenuation of electromagnetic signals in seawater, a distance of 100 meters between the AUVs is ideal, with a maximum detection depth of approximately 50 meters. By reducing the distance L between the two AUVs, detection at different depths can be achieved.

[0044] The distance between the transmitting positive electrode 12 and the transmitting negative electrode 13 of the induced polarization method is 15 meters. The transmission waveform is a bipolar square wave with a transmission period of 2 seconds, with one transmission every 10 seconds. The receiving frequency of the Ag / AgCl electrode on the receiving end is set to 250Hz-1000Hz. During the acquisition process, the AUV is always kept approximately 15 meters above the bottom and at a speed of 1 knot (0.5m / s).

[0045] The induced polarization transmitting device includes an induced polarization control chamber 3, a first watertight cable 4, a transmitting end positive electrode 5 and a transmitting end negative electrode 6. The induced polarization control chamber 3 is fixed to the shell of the first underwater autonomous robot 1, the first watertight cable 4 is installed at the end of the first underwater autonomous robot 1, the transmitting end positive electrode 5 is installed at the tail of the first underwater autonomous robot 1, and the transmitting end negative electrode 6 is fixed to the first watertight cable 4. A transmitting electric field 7 is formed between the transmitting end positive electrode 5 and the transmitting end negative electrode 6.

[0046] The spontaneous potential collection equipment includes a spontaneous potential collection chamber 8, a second watertight cable 9 and several pairs of Ag / AgCl non-polarizable electrodes 10. The spontaneous potential collection chamber 8 is fixed to the outer shell of the second underwater autonomous robot 2, the second watertight cable 9 is installed at the end of the second underwater autonomous robot 2, and the Ag / AgCl non-polarizable electrodes 10 are distributed at the tail of the second underwater autonomous robot 2 and on the second watertight cable 9, and are used to collect mixed data of induced polarization and spontaneous potential.

[0047] Specifically, the excitation polarization control chamber is installed on the belly of the first underwater autonomous robot; the positive electrode of the transmitter is installed on the tail of the first underwater autonomous robot, and the negative electrode of the transmitter is installed on the first watertight cable 15 meters away from the positive electrode of the transmitter. A buoyancy ball is installed on the first watertight cable between the positive and negative electrodes to ensure the safe operation of the first underwater autonomous robot. The natural potential collection chamber is installed on the belly of the second underwater autonomous robot, and the first pair of Ag / AgCl non-polarized electrodes are installed on the tail of the second underwater autonomous robot with a spacing of approximately 1.2 meters. The other two pairs of electrodes are installed on the second watertight cable with a spacing of 15 meters. The spacing between the electrode pairs can be appropriately increased, but if the spacing is too large, the extension rod will be too long, affecting the safe operation of the AUV and introducing noise.

[0048] Example 2

[0049] See also Figure 5 , the data processing method for the joint acquisition of ocean induced polarization and spontaneous potential includes:

[0050] Collect mixed data of induced polarization and spontaneous potential using equipment carried by an underwater autonomous robot;

[0051] Resampling is used to obtain spontaneous potential data, which is then re-interpolated to the acquisition frequency. The interpolated data is then subtracted from the original data to obtain induced polarization data, achieving a preliminary separation of the two data types.

[0052] The two types of data after preliminary separation are subjected to denoising respectively to improve data quality;

[0053] The denoised data were jointly inverted using a joint inversion method based on cross-gradient structure constraints to obtain a detailed distribution image of seabed sulfides.

[0054] Specifically, the Ag / AgCl non-polarizable electrode collects mixed data of induced polarization and natural potential. In implementation 1, the acquisition frequency is set above 250 Hz. However, the bipolar square wave emission frequency is low, and the induced secondary electric field only exists for a period of time near the rising and falling edges. Therefore, resampling is used to obtain the natural potential data. The resampled natural potential data is re-interpolated to the acquisition frequency, and then the interpolated data is subtracted from the collected original data to obtain the induced polarization data. The two types of data are then denoised separately. The noise of the natural potential data mainly includes linear drift, temperature, etc. The induced polarization data mainly filters out the low-frequency interference of the natural potential. The denoised induced polarization data and natural potential data are jointly inverted based on cross-gradients to obtain the fine distribution of seabed sulfide minerals.

[0055] Specifically, the target functional for the joint inversion of the three-dimensional natural potential constrained by the cross-gradient structure and the induced polarization method is as follows:

[0056]

[0057] The superscripts sp and ip represent the spontaneous potential and induced polarization data, respectively. is the data weighting matrix, is the predicted data in the inversion, The observed data after denoising, is the regularization factor, which is used to control the weight of the model constraint. is the model weight matrix, are the model parameters obtained by inversion, is the reference model, It is used to control the weight of the cross term in the joint inversion;

[0058] The following iterative equations for model changes are obtained by linearized least squares inversion:

[0059]

[0060] in, , , , , , , , is a constant coefficient used to control the weight of the cross-gradient constraint in the objective functional.

[0061] This paper proposes a combined induced polarization and spontaneous potential data acquisition device and data processing method for an autonomous underwater vehicle. Numerical simulation optimizes electrode placement, enabling high-precision acquisition of multiple electromagnetic data without disrupting the AUV's normal operation. Joint inversion reveals the fine structure of seafloor sulfides, facilitating precise exploration and resource assessment in my country's southwest Indian Ocean sulfide contract area.

[0062] The basic principles, main features, and advantages of the present invention are shown and described above. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and modifications are intended to fall within the scope of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A combined ocean induced polarization and spontaneous potential acquisition device, characterized in that: It comprises a first underwater autonomous robot (1) and a second underwater autonomous robot (2), wherein the first underwater autonomous robot (1) is equipped with an induced polarization emission device, and the second underwater autonomous robot (2) is equipped with a natural potential acquisition device; The induced polarization transmitting device comprises an induced polarization control chamber (3), a first watertight cable (4), a transmitting end positive pole (5) and a transmitting end negative pole (6), wherein the induced polarization control chamber (3) is fixed on the outer shell of the first underwater autonomous robot (1), the first watertight cable (4) is installed at the end of the first underwater autonomous robot (1), the transmitting end positive pole (5) is installed at the tail of the first underwater autonomous robot (1), the transmitting end negative pole (6) is fixed on the first watertight cable (4), and a transmitting electric field (7) is formed between the transmitting end positive pole (5) and the transmitting end negative pole (6); The spontaneous potential acquisition device comprises a spontaneous potential acquisition chamber (8), a second watertight cable (9) and a plurality of pairs of Ag / AgCl non-polarizable electrodes (10), wherein the spontaneous potential acquisition chamber (8) is fixed on the outer shell of the second underwater autonomous robot (2), the second watertight cable (9) is installed at the end of the second underwater autonomous robot (2), and the Ag / AgCl non-polarizable electrodes (10) are distributed at the tail of the second underwater autonomous robot (2) and on the second watertight cable (9) for acquiring mixed data of induced polarization and spontaneous potential.

2. The combined ocean induced polarization and spontaneous potential acquisition device according to claim 1, characterized in that: The invention also includes a plurality of buoyancy balls (11), each of which has a groove in the center and is sequentially distributed on the first watertight cable (4) and the second watertight cable (9), so as to maintain an upward buoyancy and ensure the safe operation of the first underwater autonomous robot (1) and the second underwater autonomous robot (2).

3. The combined ocean induced polarization and spontaneous potential acquisition device according to claim 1, characterized in that: It also includes a scientific research vessel (12), on which an ultra-short baseline receiving device is installed, and an underwater autonomous robot is installed with an ultra-short baseline transmitting device, so that the position of the underwater robot and the distance between the underwater autonomous robots can be located in real time through the cooperation of the transmitting and receiving devices.

4. The combined ocean induced polarization and spontaneous potential acquisition device according to claim 1, characterized in that: The distance between the first underwater autonomous robot (1) and the second underwater autonomous robot (2) is 100 meters, the distance between the transmitting end positive pole (5) and the transmitting end negative pole (6) is 15 meters, the transmitting waveform is a bipolar square wave, the transmitting period is 2 seconds, and the transmitting is performed once every 10 seconds.

5. The combined ocean induced polarization and spontaneous potential acquisition device according to claim 1, characterized in that: The distance between two adjacent Ag / AgCl non-polarized electrodes (10) is 15 meters, and the receiving frequency of the receiving end Ag / AgCl non-polarized electrode (10) is set to 250 Hz-1000 Hz.

6. The combined ocean induced polarization and spontaneous potential acquisition device according to claim 1, characterized in that: The underwater autonomous robot is equipped with an altimeter at the bottom to control the height from the seabed (13). During the acquisition process, the underwater autonomous robot is controlled to be 15 meters away from the seabed (13) and the speed is controlled at 0.5 m / s.

7. A method for processing data collected by combining ocean induced polarization and spontaneous potential, wherein the method comprises collecting data using the apparatus for collecting ocean induced polarization and spontaneous potential according to any one of claims 1 to 6, wherein the apparatus is characterized in that: include: Collect mixed data of induced polarization and spontaneous potential using equipment carried by an underwater autonomous robot; Resampling is used to obtain spontaneous potential data, which is then re-interpolated to the acquisition frequency. The interpolated data is then subtracted from the original data to obtain induced polarization data, achieving a preliminary separation of the two data types. The two types of data after preliminary separation are subjected to denoising respectively to improve data quality; The denoised data were jointly inverted using a joint inversion method based on cross-gradient structure constraints to obtain a detailed distribution image of seabed sulfides.

8. The method for processing data from combined ocean induced polarization and spontaneous potential acquisition according to claim 7, characterized in that: The target functional for the joint inversion of the three-dimensional natural potential constrained by the cross-gradient structure and the induced polarization method is as follows: ； The superscripts sp and ip represent the spontaneous potential and induced polarization data, respectively. is the data weighting matrix, is the predicted data in the inversion, is the observed data after denoising, is the regularization factor, which is used to control the weight of the model constraint. is the model weight matrix, are the model parameters obtained by inversion, is the reference model, is a constant coefficient, which is used to control the weight of the cross term in the joint inversion; The following iterative equations for model changes are obtained by linearized least squares inversion: ； in, , , , , , .

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