CN112731539B - Zero-magnetic-flux multi-coil receiving transient electromagnetic method detection device - Google Patents
Zero-magnetic-flux multi-coil receiving transient electromagnetic method detection device Download PDFInfo
- Publication number
- CN112731539B CN112731539B CN202011473166.7A CN202011473166A CN112731539B CN 112731539 B CN112731539 B CN 112731539B CN 202011473166 A CN202011473166 A CN 202011473166A CN 112731539 B CN112731539 B CN 112731539B
- Authority
- CN
- China
- Prior art keywords
- coil
- receiving
- receiving coil
- sector
- transmitting
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
- G01V3/00—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation
- G01V3/08—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation operating with magnetic or electric fields produced or modified by objects or geological structures or by detecting devices
- G01V3/10—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation operating with magnetic or electric fields produced or modified by objects or geological structures or by detecting devices using induction coils
Landscapes
- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Remote Sensing (AREA)
- Life Sciences & Earth Sciences (AREA)
- Electromagnetism (AREA)
- Environmental & Geological Engineering (AREA)
- Geology (AREA)
- General Life Sciences & Earth Sciences (AREA)
- General Physics & Mathematics (AREA)
- Geophysics (AREA)
- Geophysics And Detection Of Objects (AREA)
Abstract
The invention discloses a zero-magnetic-flux multi-coil receiving transient electromagnetic method detection device which comprises a transmitter, a transmitting coil, a receiving coil and a receiver, wherein the transmitting coil is a circular loop, a multi-turn loop or a single-turn loop and is connected with the transmitter. The receiving coil is composed of a plurality of fan-shaped return wires which are equal in size and same in shape. The receiving coils are connected in series and are connected with a receiver. The device adopts the receiving coil with a special shape, and the total magnetic flux of the primary magnetic field generated by the transmitting coil in the receiving coil can be zero by adjusting the proper position, so that the interference of the primary field on the receiving coil is effectively eliminated. The transient electromagnetic detection device has the advantages that the detection dead zone of the transient electromagnetic method is greatly reduced, and meanwhile, the device is not influenced by a primary field, so that larger transmitting current can be loaded, and the detection depth is increased.
Description
Technical Field
The invention relates to the field of geophysical electromagnetic prospecting, in particular to a detection device for transient electromagnetic prospecting. The invention can realize that the total magnetic flux of the primary field generated by the transmitting coil is zero in the receiving coil.
Background
The transient electromagnetic method is a kind of geophysical electrical prospecting method, its detection principle is that a primary magnetic field is excited by means of transmitting coil, then the transmitting current is cut off, in the gap of current cut-off the electromagnetic induction law can produce induced eddy current due to the sudden change of magnetic field in the underground electric medium, so as to produce secondary magnetic field, and the receiving coil placed on the ground can utilize observation of secondary magnetic field to infer the distribution of underground abnormal body.
From the principle, the primary field is the interference field to the receiving coil, and the ideal state of the transient electromagnetic method is that the receiving coil only receives the secondary field, but, the current observation device has the important defect that: the receiving coil receives the primary field and the secondary field simultaneously.
Most of the devices currently used for transient electromagnetic detection fall into two categories, one being the traditional observation devices introduced earlier or simulated foreign developments or variants thereof, for example: a central loop device, an overlapping loop device, etc., which have obvious disadvantages: the receiving coil is subject to significant interference from the primary field, and in the case where the transmitting coil current is not switched off, the receiving coil receives the total field signal containing the primary field transmitted by the transmitting coil, and the secondary field generated by the subsurface medium. And the larger the transmitting power is, the more the influence of the primary field is, so that the device has a near-surface detection blind zone of about 15 to 40 meters, and the detection depth of the transient electromagnetic method is limited.
The other is some devices for eliminating the influence of the primary field disclosed in recent years, for example, patent nos. CN110187395A, CN106908845A, CN103837899A and CN101776770A, which weaken the influence of the primary field by different methods, for example, a method of canceling the primary field by two coils emitting opposite current directions, but even though the primary field is eliminated, the problem of insufficient self-emitting power is directly caused, and the detection in a large depth cannot be performed.
Disclosure of Invention
In order to solve the problems that a receiving coil is easily influenced by a primary field and the transmitting power is low, the invention provides a novel device for transient electromagnetic detection.
In order to achieve the purpose, the technical scheme adopted by the invention is as follows:
a zero-magnetic-flux multi-coil receiving transient electromagnetic method detection device comprises a transmitter, a transmitting coil, a receiving coil and a receiver, wherein the transmitting coil is directly connected with the transmitter in series, the receiving coil is connected with the receiver in series, and the transmitting coil is a circular loop, a multi-turn loop or a single-turn loop; the receiving coils are composed of a plurality of 'fan-shaped' loop wires which are equal in size and same in shape, the receiving coils are connected in series, all the 'fan-shaped' receiving coils are located on the same plane and are coplanar with the transmitting coil, all the receiving coils have equivalence, and the received observation signals are the same.
Further, the position of the "fan" receiving coil is the key to eliminating the primary field, and the receiving coil should be located at a position where there is an overlapping area between the "fan" receiving coil and the transmitting coil, which is described in detail as follows: the inner radius arc of the "sector" receiver coil falls inside the transmitter coil and does not coincide with the transmitter coil, while the outer radius arc of the "sector" receiver coil falls outside the ring of the transmitter coil and does not overlap with the transmitter coil. Two radii of the central angle of the "sector" receiver coil intersect the receiver coil perpendicularly.
Furthermore, the number of turns of the "sector" receiving coils can be adjusted according to needs, but the winding direction of each "sector" receiving coil should be the same, and the connecting line between two adjacent "sector" receiving coils should be as close as possible, preferably located at both sides of the transmitting coil;
taking any one of the receiver coils as an example, a "sector" of the receiver coil area is partially located in the inner region of the transmitter coil, and partially located in the outer region of the transmitter coil. After the primary magnetic field is generated by energizing the transmitting coil, a part of downward magnetic field is contained in the receiving coil, and a part of upward magnetic field is also contained in the receiving coil, so that the areas of two magnetic flux directions are changed by adjusting the inner radius and the outer radius of the sector-shaped receiving coil or moving the position of the sector-shaped receiving coil. There can be a position where the passing upward and downward magnetic fluxes in the receiving coil cancel each other out so that the total magnetic flux in the receiving coil is zero, thereby achieving the purpose of eliminating the primary field.
The beneficial effect of the invention is that,
(1) the device adopts the receiving coil with a special shape, and the total magnetic flux of the primary magnetic field generated by the transmitting coil in the receiving coil can be zero by adjusting the proper position, so that the interference of the primary field on the receiving coil is effectively eliminated. The transient electromagnetic detection device has the advantages that the detection dead zone of the transient electromagnetic method is greatly reduced, and meanwhile, the device is not influenced by a primary field, so that larger transmitting current can be loaded, and the detection depth is increased.
(2) The "sector" receiving coil inner radius arc edge described above refers to an arc having a smaller radius corresponding to a central angle, which is sandwiched between two radii of the central angle of the sector.
(3) The arc edge of the outer radius of the sector-shaped receiving coil is an arc which is formed by two radii of the central angle of the sector and has a larger radius corresponding to the central angle.
Drawings
Fig. 1 is a schematic diagram of a zero-flux multi-coil receiving transient electromagnetic method detection device of the present invention, in which 1 is a number 1 receiving coil, 2 is a number 2 receiving coil, 3 is a number 3 receiving coil, 4 is a number 4 receiving coil, 5 is a transmitting coil, 6 is a transmitting current direction, 7 is a direction of a primary magnetic field, 8 is a transmitter, and 9 is a receiver;
FIG. 2 is a comparison graph of theoretical attenuation curves of the secondary field of the zero-flux device and the central loop device in the uniform half-space model;
FIG. 3 is a comparison graph of theoretical attenuation curves of a secondary field of a zero-flux device and a central loop device provided by the invention under a one-dimensional layered stratum model;
FIG. 4 is a schematic diagram of a zero flux device according to the present invention with only one "sector" receiver coil; wherein, 1-1 is a receiving coil, 5 is a transmitting coil, 6 is a transmitting current direction, 7 is a direction of a primary magnetic field, 8 is a transmitter, and 9 is a receiver;
fig. 5 is a comparison graph of a theoretical secondary field attenuation curve of a single 'fan-shaped' receiving coil device and a theoretical secondary field attenuation curve of a central loop device under a one-dimensional layered stratum model.
Detailed Description
The following description of the embodiments of the present invention is provided in connection with the accompanying drawings, and it is to be understood that the invention is not limited thereto, but rather is intended to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims.
Example 1
Fig. 1 is a schematic structural diagram of a zero-flux multi-coil receiving transient electromagnetic detection device, the main core device of the invention is a coil between a transmitter 8 and a receiver 9, the coil is composed of a transmitting coil 5 externally connected with the transmitter 8 and a plurality of receiving coils, and all the receiving coils are connected in series and connected with the receiver 9.
Embodiment 1 will be described with 4 receiving coils as an example device. In practice the number of "sector" receiving coils may not be limited to this example.
As can be seen from fig. 1, the detection device according to the present invention comprises a transmitter 8, a transmitting coil 5, a "sector" receiving coil and a receiver 9. The sector receiving coils are a No. 1 receiving coil 1, a No. 2 receiving coil 2, a No. 3 receiving coil 3 and a No. 4 receiving coil 4. The transmitter 8 is connected with the transmitting coil 5, the receiving coil 1, the receiving coil 2, the receiving coil 3 and the receiving coil 4 are sequentially connected in series, and only one input end and one output end are located at the position where the receiving coil 1 starts to be wound. And the input and output terminals of the receiving coil are connected to a receiver 9.
The 4 transmitting coils 5 are positioned on the same plane and are coplanar with the transmitting coils 5.
The 4 transmitting coils 5 are completely the same, the winding direction of the 4 transmitting coils starts from the No. 1 coil, the input end forms 4 fan-shaped radiuses and arc lengths corresponding to the outer radiuses, and the output end forms a ring shape inside the transmitting coils 5 to form the arc lengths corresponding to the inner radiuses of the 4 fan-shaped receiving coils. The wires of the input end and the output end are connected at the No. 4 coil to form a closed loop, and the finally formed effective detection area is the sum of the loop areas formed by 4 sectors.
The inner radius arc of the "sector" receiving coil is located inside the orthographic projection of the transmitting coil 5, while the outer radius arc of the "sector" receiving coil is located outside the orthographic projection of the transmitting coil 5.
When the transmitter 8 transmits a current I of a certain magnitude (assuming that the current is counterclockwise, as shown in fig. 1), a magnetic field is generated around the transmitting coil 5, the magnetic field is perpendicular to the transmitting coil 5 and outward inside the transmitting coil 5, which satisfies the right-hand helical rule, and the direction of the magnetic induction line is inward outside the transmitting coil 5. By adjusting the inner and outer radial arc lengths of the "sector" receiver coil, the total flux passing through can eventually be made zero.
After the position and size of the receiving coil are adjusted to be free from the influence of a primary field, the device can be used for performing electrical prospecting. The method comprises the following specific steps:
1. switching on a power supply, introducing current into the transmitting coil 5, and switching off the transmitting current at a certain moment after the current is kept stable; causing the primary field to suddenly disappear;
2. after the current is completely cut off, the induced electromotive force of the receiving coil begins to be recorded, and the induced electromotive force reflects the change rate of the magnetic flux in the receiving coil;
3. and carrying out normalization processing on the recorded induced electric data, sampling in a certain windowing mode, removing early and late noises by using methods such as wavelet denoising and the like, and finally obtaining an attenuation curve of a secondary field.
FIG. 2 is a simulated attenuation curve of the device of FIG. 1 in a uniform half-space model designed to have a resistivity of 10 Ω. m, in comparison to a center loop device. When 4 'fan-shaped' receiving coils are adopted, the actual equivalent detection position is the central point, and after normalization processing, the device is equivalent to a central loop device under the condition of ideal turn-off step turn-off, namely, under the condition of no primary field influence. As can be seen from fig. 2, the device of the present invention perfectly fits the calculated results to the results of the central loop.
Example 2
Still taking the example apparatus of example 1 as an example, a stratigraphic model was designed assuming the subsurface medium is stratified, i.e., the resistivity varies only vertically, with the resistivity set as: the resistivity of the first layer is 100 omega.m, and the thickness of the first layer is 100 m; the resistivity of the second layer is 200 omega.m, and the thickness of the second layer is 100 m; the resistivity of the third layer is 100 omega.m, and the thickness of the third layer is 100 m; the resistivity of the fourth layer is 500 omega.m, the thickness of the fourth layer is the lower half space, and the thickness is large enough;
fig. 3 is a simulated attenuation curve of a one-dimensional layer model, and it can be seen that when 4 coils are distributed symmetrically about the center, the normalized secondary field signal completely coincides with the theoretical data observed by the central loop.
Example 3
Based on the device in example 1, only changing the number of the receiving coils can still maintain zero magnetic flux of the primary field when the receiving coils are only one "fan-shaped" receiving coil, because the "fan-shaped" receiving coils can independently realize zero magnetic flux, and the "fan-shaped" receiving coils are only in series connection.
In the arrangement shown in fig. 4, the receiving coil 1-1 is in series with the receiver 9, the transmitting coil 5 is in series with the transmitter 8, and the "sector" receiving coil 1-1 is in the same plane as the transmitting coil 5.
In such a case as in fig. 4, the "sector" receiving coils are not centrosymmetrically distributed, with the equivalent receiving point not at the center, which results in weaker coupling with the secondary field.
As shown in fig. 5, after the one-dimensional layer model in example 2 is simulated, after the current is turned off, the phenomenon of inconsistency occurs between the secondary field attenuation signal received by the device in fig. 4 and the received signal of the central device in an early stage, and the attenuation signals of the two devices are gradually the same in a later stage along with the extension of the observation time.
Claims (2)
1. A zero-magnetic-flux multi-coil received transient electromagnetic detection device is characterized in that: the detection device comprises a transmitter (8), a transmitting coil (5), a receiving coil and a receiver (9), wherein the transmitting coil (5) is connected with the transmitter (8) in series, and the receiving coil is connected with the receiver (9) in series; the transmitting coil is a circular loop, a multi-turn loop or a single-turn loop; the receiving coils are composed of a plurality of 'fan-shaped' loop wires which are equal in size and same in shape, the receiving coils are connected in series, all the 'fan-shaped' receiving coils are positioned on the same plane and are coplanar with the transmitting coil (5), all the receiving coils have equivalence, and the received observation signals are the same;
the sector receiving coil and the transmitting coil (5) are overlapped, the arc edge of the inner radius of the sector receiving coil falls inside the transmitting coil (5) and is not overlapped with the transmitting coil (5), the arc edge of the outer radius of the sector receiving coil falls outside the ring of the transmitting coil (5) and is not overlapped with the transmitting coil (5), and two radiuses of the central angle of the sector receiving coil are vertically intersected with the receiving coil;
the number of turns of the 'sector' receiving coils is adjusted according to needs, but the winding direction of each 'sector' receiving coil is the same, and connecting lines between two adjacent 'sector' receiving coils are close to each other, and the selected method is that the receiving coils are positioned on two sides of the transmitting coil (5); for any receiving coil, one part of the area of the sector receiving coil is positioned in the inner area of the transmitting coil (5), the other part of the area of the sector receiving coil is positioned in the outer area of the transmitting coil (5), after the transmitting coil (5) is electrified to generate a primary magnetic field, the receiving coil not only contains a part of downward magnetic field, but also contains a part of upward magnetic field, and the areas of the two magnetic flux directions are changed by adjusting the inner radius and the outer radius of the sector receiving coil or moving the position of the sector receiving coil, so that a position can exist, the upward and downward magnetic fluxes passing through the receiving coil are mutually offset, and the total magnetic flux in the receiving coil is zero, thereby achieving the aim of eliminating the primary field.
2. The zero-flux multi-coil received transient electromagnetic detection device of claim 1, wherein: the size and the number of turns of the transmitting coil (5) are adjusted according to requirements.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011473166.7A CN112731539B (en) | 2020-12-15 | 2020-12-15 | Zero-magnetic-flux multi-coil receiving transient electromagnetic method detection device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011473166.7A CN112731539B (en) | 2020-12-15 | 2020-12-15 | Zero-magnetic-flux multi-coil receiving transient electromagnetic method detection device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN112731539A CN112731539A (en) | 2021-04-30 |
| CN112731539B true CN112731539B (en) | 2022-05-13 |
Family
ID=75602040
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202011473166.7A Active CN112731539B (en) | 2020-12-15 | 2020-12-15 | Zero-magnetic-flux multi-coil receiving transient electromagnetic method detection device |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN112731539B (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113608267A (en) * | 2021-06-08 | 2021-11-05 | 华北科技学院(中国煤矿安全技术培训中心) | Double-circuit zero-flux transient electromagnetic detection device |
| CN114814957A (en) * | 2022-04-15 | 2022-07-29 | 吉林大学 | Plane gradient measurement method based on transient electromagnetic method |
| CN116953803B (en) * | 2023-08-22 | 2024-05-14 | 中南大学 | Abnormal body information processing method and coil sensor device applied by same |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103590825A (en) * | 2013-10-26 | 2014-02-19 | 中国石油化工集团公司 | Transient electromagnetic well-logging probe detection system |
| CN209102918U (en) * | 2018-12-28 | 2019-07-12 | 国科（重庆）仪器有限公司 | A kind of transient electromagnetic apparatus |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8305081B2 (en) * | 2009-07-16 | 2012-11-06 | Baker Hughes Incorporated | Cancellation of vibration noise in deep transient resistivity measurements while drilling |
| CN101776770B (en) * | 2010-02-26 | 2012-07-25 | 重庆大学 | Electromagnetic prospecting sending-receiving integration method and device |
| CN110187395B (en) * | 2019-06-24 | 2020-12-01 | 安徽理工大学 | Zero-magnetic-flux shallow transient electromagnetic test coil and test method thereof |
| CN111273355B (en) * | 2020-03-16 | 2021-08-13 | 中国科学技术大学 | Advanced detection method and advanced detection system for roadway |
-
2020
- 2020-12-15 CN CN202011473166.7A patent/CN112731539B/en active Active
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103590825A (en) * | 2013-10-26 | 2014-02-19 | 中国石油化工集团公司 | Transient electromagnetic well-logging probe detection system |
| CN209102918U (en) * | 2018-12-28 | 2019-07-12 | 国科（重庆）仪器有限公司 | A kind of transient electromagnetic apparatus |
Also Published As
| Publication number | Publication date |
|---|---|
| CN112731539A (en) | 2021-04-30 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN112731539B (en) | Zero-magnetic-flux multi-coil receiving transient electromagnetic method detection device | |
| EP3685198B1 (en) | Device and method for foreign object detection in wireless energy transfer | |
| CN102680567B (en) | Vortex finder | |
| CN106062309B (en) | Induction logging sensor | |
| WO2008036077A3 (en) | Multi-axial antenna and method for use in downhole tools | |
| CN110187395B (en) | Zero-magnetic-flux shallow transient electromagnetic test coil and test method thereof | |
| CN104215688B (en) | Can split high voltage transmission line online electromagnetic nondestructive device | |
| CN109884718B (en) | Magnetic resonance water detection device and method capable of effectively reducing dead time | |
| JP2009539090A (en) | Detection system suitable for identifying and tracking buried pipes or other objects embedded in the ground or embedded in civil engineering structures | |
| CN101676518A (en) | Horizontal guiding drill while-drilling detection early warning system | |
| CN109209363B (en) | Through-casing formation differential resistivity logging probe structure | |
| CN103472489B (en) | The antithesis emitter of transient electromagnetic | |
| DE60222013D1 (en) | COIN DISTINCTION APPARATUS IN WHICH FREQUENCIES OF SPINS ARE MEASURED | |
| CN112666613A (en) | Weak magnetic flux coaxial coplanar single-transmitting single-receiving transient electromagnetic detection device | |
| CN210775866U (en) | Multi-transmitting-coil transient electromagnetic combination device | |
| CN105629313B (en) | Move the magnetic flux detection method of target in ocean | |
| CN110767979A (en) | Borehole electromagnetic wave transmitting antenna for subway diaphragm wall leakage detection | |
| US8610311B1 (en) | Passive power generation system | |
| CN103775076B (en) | Magnetic susceptibility checkout gear | |
| RU97111162A (en) | METHOD FOR DETERMINING ELECTRIC CONDUCTIVITY OF SOIL LAYER | |
| CN214474011U (en) | Weak magnetic flux coaxial coplanar single-transmitting single-receiving transient electromagnetic detection device | |
| CN208521010U (en) | A kind of grounded screen breakpoint detection device of arch form solenoid transmission coil | |
| CN114814957A (en) | Plane gradient measurement method based on transient electromagnetic method | |
| CN107765316B (en) | Cable path detection multi-frequency emission system and method and cable path detection instrument | |
| US8310237B2 (en) | Apparatus for and method of detecting a conductive object |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |