Semi-seabed electromagnetic detection device and method

Abstract

The invention discloses a semi-seabed electromagnetic detection device and method, and solves the technical problem that the distribution of deep sulfide ores cannot be accurately represented in the prior art. The device comprises a seabed fixed transmitting device and an underwater autonomous robot receiving system, the seabed fixed transmitting device comprises a seabed current source transmitting device and an anchoring unit, and the underwater autonomous robot receiving system is provided with a sensor receiving array and a data acquisition module; the seabed current source transmitting device comprises a transmitting source control bin, a first watertight cable, a transmitting end positive pole and a transmitting end negative pole, the anchoring unit comprises an anchor body and an acoustic positioning beacon, and the sensor receiving array comprises an electric field acquisition bin, a second watertight cable, a plurality of pairs of Ag / AgCl non-polarized electrodes and a three-component magnetometer. According to the method, the distribution characteristics of deep seabed sulfides can be more accurately detected, the drilling risk is reduced, and the exploration accuracy and the resource quantity evaluation reliability are improved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of marine geophysics, and particularly relates to a semi-submarine electromagnetic detection device and method. BACKGROUND

[0002] Seafloor polymetallic sulfide is rich in copper, zinc, silver, gold and other metals, and is an important potential strategic metal source. The existing detection methods, such as seafloor transient electromagnetic method, have the transmitting loop located in the high-conductivity seawater, and the electromagnetic energy penetrating the seafloor is limited, so the detection depth is shallow, and it is difficult to accurately detect the sulfide deposits with a depth of more than 80 m. Therefore, it is urgent to develop an electromagnetic method with both detection depth and detection efficiency to improve the detection capability of the middle-deep seafloor sulfide. At the same time, the traditional inversion has a higher requirement for the collection quality of the detection data, and it is necessary to propose a sulfide indicator based on data driving to realize the rapid identification and delineation of the sulfide distribution. Therefore, the present application provides a semi-submarine electromagnetic device with a fixed transmitting source on the seafloor and underwater mobile collection, and provides the detection capability of the high-middle-deep seafloor sulfide. SUMMARY

[0003] The present application aims to provide a semi-submarine electromagnetic detection device and method to solve the technical problem that the existing technology cannot accurately characterize the middle-deep seafloor sulfide ore morphology.

[0004] To achieve the above-mentioned purpose, the present application provides the following technical solutions: In a first aspect, the present application provides a semi-submarine electromagnetic detection device, comprising a seafloor fixed transmitting device and an underwater autonomous robot receiving system, the seafloor fixed transmitting device comprising a seafloor current source transmitting device and an anchoring unit, and the underwater autonomous robot receiving system being provided with a sensor receiving array and a data acquisition module; Further, the seafloor current source transmitting device comprises a transmitting source control bin, a first water-tight cable, a transmitting end positive electrode and a transmitting end negative electrode, the transmitting source control bin being connected with the transmitting end positive electrode and the transmitting end negative electrode through the first water-tight cable, and the current source transmitting device transmitting a primary current field to the seafloor through the transmitting end; Further, the sensor receiving array comprises an electric field collection bin, a second water-tight cable and a plurality of pairs of Ag / AgCl non-polarizable electrodes and a three-component magnetometer, the electric field collection bin and the three-component magnetometer being fixed on the shell of the underwater autonomous robot receiving system, the second water-tight cable being installed at the end of the underwater autonomous robot, and the Ag / AgCl non-polarizable electrodes being distributed and arranged on the tail of the underwater autonomous robot receiving system and the second water-tight cable, the sensor receiving array being used for receiving the secondary electromagnetic field data generated by the seafloor sulfide sensing; Further, the anchoring unit of the seabed fixed transmitting system comprises an anchor body, a buoyancy adjusting assembly and an acoustic positioning beacon, the anchoring unit keeps the transmitting coil posture stable in the environment with a sea current speed of ≤3 m / s by load adjustment, the posture deviation is ≤5°, and the acoustic positioning beacon is sequentially arranged at the head end and tail end of the first water-tight cable and used for positioning the end point positions of the seabed fixed transmitting source.

[0005] Further, the transmitting source can generate an alternating electromagnetic field with a frequency range of 64 Hz-2048 Hz and support frequency multiplication step adjustment with a multiplication factor of 2; the distance between the transmitting end positive pole and the transmitting end negative pole is 200 meters, and the transmitting waveform is a bipolar square wave.

[0006] Further, the receiving sensor array of the underwater mobile receiving system is a multi-component electric field sensor and a magnetic field sensor, the spatial arrangement distance between two adjacent Ag / AgCl non-polarized electrodes is 2-4 meters to cover the main lobe area of the electromagnetic field radiated by the transmitting system, and the receiving frequency of the receiving end Ag / AgCl non-polarized electrode and the multi-component magnetometer is set to 64 Hz-2048 Hz.

[0007] Further, the underwater autonomous robot receiving system carries out the collection of electric field and magnetic field signals according to the planned path, and in the collection process, the underwater autonomous robot receiving system is controlled to be 15 meters away from the seabed and the speed is controlled to be 1 m / s.

[0008] In a second aspect, the present application provides a seabed polymetallic sulfide detection method based on the above-mentioned device, comprising the following steps: Deploying the transmitting system: transporting the seabed fixed transmitting system to the target area by the research ship, fixing the seabed fixed transmitting system to the seabed by the anchoring unit, debugging the parameters of the transmitting source and starting the electromagnetic field transmission; Planning the receiving path: planning the cruise path and survey line distribution of the underwater autonomous robot receiving system according to the position, orientation and detection range of the seabed transmitting system, planning the survey line to be parallel to the long axis direction of the transmitting source and ensuring that the underwater autonomous robot receiving system moves along the preset trajectory in the electromagnetic field coverage area, and the underwater mobile receiving system collects the secondary electromagnetic signals in real time during the movement, positions the data and records the synchronization time stamp with the transmitting signal; Data processing and analysis: based on the amplitude, phase characteristics and positioning information of the received signal, calculating the sulfide indicator factor of the electric field and the magnetic field, and identifying the spatial position and scale of the seabed polymetallic sulfide.

[0009] Further, the calculation formula of the sulfide indicator factor is as follows: wherein, is a sulfide indicator factor of an electric field, is a component of an electric field in a direction parallel to a long axis of a fixed emission source on a seabed, is a component of an electric field in a direction parallel to a long axis of a fixed emission source on a seabed, is a component of an electric field in a direction parallel to a long axis of a fixed emission source on a seabed, is a sulfide indicator factor of a magnetic field, is a component of a magnetic field in a direction perpendicular to a long axis of a fixed emission source on a seabed, is a horizontal component of a magnetic field in a direction perpendicular to a long axis of a fixed emission source on a seabed, is a component of an electric field in a direction perpendicular to a long axis of a fixed emission source on a seabed.

[0010] Based on the above technical solutions, the embodiments of the present application can at least produce the following technical effects: (1) The semi-seabed electromagnetic detection device provided by the present application has a fixed emission source on the seabed and directly contacts the seabed, can send a large-power alternating current to the seabed, makes the sulfide in the deep part of the seabed produce an induced secondary field, and thus improves the detection depth of the electromagnetic method. Through the underwater autonomous robot receiving system, the array sensor is moved to collect the induced electromagnetic secondary field parameters, combined with the multi-frequency emission of the emission source, the three-dimensional detection of the sulfide ore body in space and the depth direction at different depths is realized, and the exploration efficiency is improved.

[0011] (2) The semi-seabed electromagnetic detection method provided by the present application can more accurately explain the distribution characteristics of the seabed sulfide by obtaining the measured data of different regions, by normalization analysis, and by comprehensively analyzing the electric field and magnetic field data, reduces the multi-solution, and improves the accuracy and reliability of the exploration. DETAILED DESCRIPTION

[0012] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor on the basis of the drawings shown.

[0013] Fig. 1 is a semi-seabed electromagnetic detection schematic diagram of the present application; Fig. 2 is a typical semi-seabed electromagnetic detection electric field sulfide indicator factor distribution diagram; Fig. 3 is a typical semi-seabed electromagnetic detection magnetic field sulfide indicator factor distribution diagram; In the figure: 1, seabed fixed launching device; 101, launching source control bin; 102, first water-tight cable; 103, launching end positive pole; 104, launching end negative pole; 105, anchor body; 106, acoustic positioning beacon; 2, underwater autonomous robot receiving system; 201, electric field collection bin; 202, second water-tight cable; 203, Ag / AgCl non-polarization electrode; 204, three-component magnetometer; 3, primary current field; 4, planned path DETAILED DESCRIPTION The technical solutions in the embodiments of the present application will be described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by a person of ordinary skill in the art without creative work are within the protection scope of the present application. In addition, the technical solutions in various embodiments can be combined with each other, but it must be based on that a person of ordinary skill in the art can realize. When the combination of technical solutions appears contradictory or unachievable, it should be considered that the combination of technical solutions does not exist and is not within the protection scope of the present application.

[0014] The present embodiment provides a semi-seabed electromagnetic detection device and method, which will be described below in combination with the accompanying drawings. Figs. 1-3 The present embodiment provides a semi-seabed electromagnetic detection device and method, which will be described below in combination with the accompanying drawings.

[0015] Embodiment 1 Please refer to Fig. 1 A semi-seabed electromagnetic detection device, comprising a seabed fixed launching device 1 and an underwater autonomous robot receiving system 2, the seabed fixed launching device 1 comprising a seabed current source launching device and an anchoring unit, the underwater autonomous robot receiving system 2 being provided with a sensor receiving array and a data acquisition module; In the present embodiment, the seabed current source launching device comprises a launching source control bin 101, a first water-tight cable 102, a launching end positive pole 103 and a launching end negative pole 104, the launching source control bin 101 being connected with the launching end positive pole 103 and the launching end negative pole 104 through the first water-tight cable 102, and the current source launching device 1 emitting a primary current field 3 to the seabed through the launching end. The sensor receiving array comprises an electric field collection bin 201, a second water-tight cable 202, a plurality of pairs of Ag / AgCl non-polarizable electrodes 203, and a three-component magnetometer 204, the electric field collection bin 201 and the three-component magnetometer 204 are fixed on the shell of the underwater autonomous robot receiving system 2, the second water-tight cable 202 is installed at the end of the underwater autonomous robot 2, the Ag / AgCl non-polarizable electrodes 203 are distributed on the tail of the underwater autonomous robot receiving system 2 and the second water-tight cable 202, and the sensor receiving array is used for receiving the secondary electromagnetic field data generated by the seabed sulfide induction, in the embodiment, the measured electric field component is the survey line component consistent with the direction of the robot.

[0016] In the embodiment, the anchoring unit of the seabed fixed transmitting system comprises an anchor body 105 and an acoustic positioning beacon 106, the anchoring unit keeps the transmitting coil posture stable through load adjustment, and the acoustic positioning beacon 106 is sequentially distributed at the head end and the tail end of the first water-tight cable 102, and is used for positioning the end point position of the seabed fixed transmitting source.

[0017] In the embodiment, the transmitting source 101 can generate alternating electromagnetic fields with frequencies of 256 Hz, 512 Hz, 1024 Hz and 2048 Hz, the spacing between the transmitting end positive pole 103 and the transmitting end negative pole 104 is 200 meters, the transmitting waveform is a bipolar square wave, and the transmitting current is 100 A.

[0018] In the embodiment, the receiving sensor array of the underwater mobile receiving system is a multi-component electric field sensor and a magnetic field sensor, the spatial arrangement spacing between two adjacent Ag / AgCl non-polarizable electrodes 203 is 2 meters, the electric field along the survey line direction and the electric field in the vertical direction are measured respectively, so as to cover the main lobe region of the electromagnetic field radiated by the transmitting system, and the receiving frequency of the receiving end Ag / AgCl non-polarizable electrode and the multi-component magnetometer is set to 256 Hz-2048 Hz. In the embodiment, the underwater autonomous robot receiving system 2 collects electric field and magnetic field signals according to the planned path 4, the main survey line direction of the planned path 4 is parallel to the long axis direction of the transmitting source, in the collection process, the underwater autonomous robot receiving system 2 is controlled to be 15 meters away from the seabed, and the speed is controlled to be 1 m / s.

[0019] Embodiment 2 Please refer to Figs. 2-3 The embodiment provides a semi-seabed electromagnetic detection method, comprising the following steps: Deploying the transmitting system: transporting the seabed fixed transmitting system to the target area by the research ship, fixing the transmitting system to the seabed by the anchoring unit, debugging the transmitting source parameters and starting the electromagnetic field transmission. Planning receiving path: according to the position, orientation and detection range of the submarine transmitting system, the cruise path and survey line distribution of the underwater autonomous robot receiving system are planned, as shown in Fig. 2 and Fig. 3 The sulfide is located in the center of the detection area, the sulfide distribution is 50m*50m, and the survey line length is 400m, which is parallel to the long axis direction (Y direction) of the transmitting source. The mobile underwater receiving system collects the secondary electromagnetic signals in real time during the movement; Data processing and analysis: based on the amplitude, phase characteristics and positioning information of the received signals, the sulfide indicator factors of the electric field and the magnetic field are calculated, and the spatial position and scale of the submarine polymetallic sulfide are identified.

[0020] Specifically, the calculation formula of the sulfide indicator factor is as follows: Among them, is the electric field sulfide indicator factor, represents the electric field component parallel to the long axis direction of the fixed transmitting source on the seabed, the electric field component parallel to the transmitting source direction above the sulfide, is the electric field component parallel to the transmitting source direction; is the magnetic field sulfide indicator factor, represents the magnetic field component perpendicular to the long axis direction of the fixed transmitting source on the seabed, the horizontal component of the magnetic field perpendicular to the transmitting source direction above the sulfide, is the electric field component perpendicular to the transmitting source direction. The calculated As shown in Fig. 2 , the calculated As shown in Fig. 3 , the electric field and magnetic field sulfide indicator factors can indicate the distribution of sulfide.

[0021] The present application proposes a kind of semi-submarine electromagnetic detection device and method, by not being set fixed transmitting source on seabed, the identification and detection of seabed sulfide are realized, detection device can obtain the fine structure of seabed sulfide, serve the accurate exploration and resource evaluation of southwest Indian Ocean sulfide contract area of our country.

[0022] The basic principles and main features of the present application and the advantages of the present application are shown and described above. It should be understood by those skilled in the art that the present application is not limited by the above examples, and the above examples and descriptions in the specification are only to illustrate the principles of the present application. Without departing from the spirit and scope of the present application, various changes and improvements can be made to the present application, and these changes and improvements all fall within the scope of the claimed present application. The scope of protection claimed by the present application is defined by the appended claims and their equivalents.

Claims

1. A semi-submarine electromagnetic surveying apparatus, characterized in that, The application relates to a seabed fixed launching device (1) and an underwater autonomous robot receiving system (2), wherein the seabed fixed launching device (1) comprises a seabed current source launching device and an anchoring unit, and the underwater autonomous robot receiving system (2) is provided with a sensor receiving array and a data acquisition module. The seabed current source launching device comprises a launching source control bin (101), a first water-proof cable (102), a launching end positive electrode (103) and a launching end negative electrode (104), the launching source control bin (101) is connected with the launching end positive electrode (103) and the launching end negative electrode (104) through the first water-proof cable (102), and the seabed fixed launching device (1) launches a primary current field (3) to the seabed through the launching end. The sensor receiving array comprises an electric field collection bin (201), a second water-proof cable (202), a plurality of pairs of Ag / AgCl non-polarization electrodes (203) and a three-component magnetometer (204), the electric field collection bin (201) and the three-component magnetometer (204) are fixed on the shell of the underwater autonomous robot receiving system (2), the second water-proof cable (202) is arranged at the end of the underwater autonomous robot receiving system (2), the Ag / AgCl non-polarization electrodes (203) are arranged on the tail of the underwater autonomous robot receiving system (2) and the second water-proof cable (202), and the sensor receiving array is used for receiving secondary electromagnetic field data generated by seabed sulfide induction.

2. Semi-submerged electromagnetic surveying apparatus according to claim 1, characterised in that, The anchoring unit of the seabed fixed launching system (1) comprises an anchor body (105) and an acoustic positioning beacon (106), the anchoring unit can keep the launching coil posture stable under the condition that the sea current speed is less than or equal to 3 m / s, and the posture deviation is less than or equal to 5 degrees through load adjustment, and the acoustic positioning beacon (106) is arranged at the head end and the tail end of the first water-proof cable (102) in sequence and is used for positioning the end point position of the seabed fixed launching source.

3. The semi-submarine electromagnetic survey apparatus of claim 1, wherein, The launching source control bin (101) can generate an alternating electromagnetic field with a frequency range of 64 Hz-2048 Hz and support frequency multiplication step adjustment, and the multiplication multiple is 2.

4. The semi-submarine electromagnetic survey apparatus of claim 1, wherein, The distance between the launching end positive electrode (103) and the launching end negative electrode (104) is 200 meters, and the launching waveform is a bipolar square wave.

5. The semi-submarine electromagnetic surveying apparatus of claim 1, wherein, The sensor receiving array of the underwater autonomous robot receiving system (2) is a multi-component electric field sensor and a magnetic field sensor, the space arrangement distance between two adjacent Ag / AgCl non-polarization electrodes (203) is 2-4 meters, so as to cover the main lobe area of the electromagnetic field radiated by the launching system, and the receiving frequency of the receiving end Ag / AgCl non-polarization electrode (203) and the three-component magnetometer (204) is set as 64 Hz-2048 Hz.

6. The semi-submarine electromagnetic surveying apparatus of claim 1, wherein, The underwater autonomous robot receiving system (2) collects electric field and magnetic field signals according to a planned path (4), and in the collecting process, the underwater autonomous robot receiving system (2) is controlled to be 15 meters away from the seabed and the speed is controlled to be 1 m / s.

7. A semi-submarine electromagnetic prospecting method, in which the device according to any one of claims 1 to 6 is used for prospecting, characterized in that, The application further discloses a seabed sulfide detection method comprising the following steps: Deployment of the transmitting system: The seabed fixed transmitting system is transported to the target area by the research vessel, anchored to the seabed by the anchoring unit, the transmitting source parameters are adjusted, and the electromagnetic field is transmitted; Planning of the receiving path: According to the position, orientation and detection range of the seabed transmitting system, the cruise path and the survey line distribution of the underwater autonomous robot receiving system are planned. The survey line should be parallel to the long axis direction of the transmitting source, and the underwater autonomous robot receiving system should move along the preset trajectory in the electromagnetic field coverage area. The underwater mobile receiving system collects secondary electromagnetic signals in real time during the movement, locates the data and records the synchronization time stamp with the transmitting signal; Data processing and analysis: Based on the amplitude, phase characteristics and positioning information of the received signal, the sulfide indicator factor of the electric field and the magnetic field is calculated, and the spatial position and scale of the seabed polymetallic sulfide are identified.

8. The semi-submarine electromagnetic survey method of claim 7, wherein, The calculation formula of the sulfide indicator factor is as follows: wherein, is the electric field sulfide indicator factor, represents the electric field component parallel to the long axis of the fixed source above the sulfide, is the electric field component parallel to the long axis of the fixed source above the sulfide, is the electric field component parallel to the long axis of the fixed source, is the magnetic field sulfide indicator factor, represents the magnetic field component perpendicular to the long axis of the fixed source above the sulfide, is the magnetic field horizontal component perpendicular to the long axis of the fixed source above the sulfide, is the electric field component perpendicular to the long axis of the fixed source.

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