CN109031432A - A kind of very low frequencies and magnetotelluric union measuring method - Google Patents
A kind of very low frequencies and magnetotelluric union measuring method Download PDFInfo
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- 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
- G01V3/12—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation operating with electromagnetic waves
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- G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
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Abstract
The invention discloses a kind of very low frequencies and magnetotelluric union measuring method, belong to deep resource detection technology field.Specifically for geology of deep part stratum, the fine detection of construction, the high-resolution electrical fine structure detection of oil gas ore field deep 10km can be especially carried out.Very low frequencies and magnetotelluric union measuring method are as follows: obtain electromagnetic wave using the signal emitting-source of WEM method, i.e., frequency conversion electric current is injected to underground by big emission power, the electromagnetic wave of generation upwardly propagates to form sky wave, sky wave propagation is to ionosphere, again by ionospheric reflection to underground ore bodies, ground is finally traveled to by underground medium；Array WEM electromagnetic signal is carried out in oil gas field and the natural field electromagnetic signal of MT receives, and by WEM electromagnetic signal and the natural field electromagnetic signal combined measurement of MT and data processing inversion interpretation, obtains the high-resolution electrical fine structure in oil gas ore field deep.The present invention can be improved Neoproterozoic Progress of Residual Basins forecast of distribution precision in ultra-deep and provide scientific basis for petroleum resources assessment in the depth bounds.
Description
Technical field
Present invention relates particularly to a kind of very low frequencies and magnetotelluric union measuring method, belong to deep resource Detection Techniques neck
Domain.Specifically for geology of deep part stratum, the fine detection of construction, the high-resolution electrical property of oil gas ore field deep 10km can be especially carried out
The problems such as fine structure detects, and solves the geologic structure of Neoproterozoic in ultra-deep.
Background technique
In the detection of deep 10km geologic structure, usually used electromagnetic prospecting method is generally magnetotelluric sounding method
(MT), magnetotelluric sounding method utilizes natural field signal, and observing frequency 0.001Hz to 320Hz, what it is due to observation is natural field
Electromagnetic field signal is influenced 0.1Hz to 1Hz " dead frequency range " is extremely weak by natural field electromagnetic field, so that MT was observed in the frequency range
The quality of data is poor, due to the defective effect MT of this band frequency quality of data 10km stratum geological structure detection close to deep.
Summary of the invention
Therefore, to solve the above problem in the prior art, propose that the very low frequencies in the present invention combine survey with magnetotelluric
Amount method.
Very low frequencies provided by the invention and magnetotelluric union measuring method are as follows:
Using WEM method signal emitting-source excite electromagnetic wave upwardly propagate to form sky wave, sky wave propagation to ionosphere, then
By ionospheric reflection to underground medium, ground finally is traveled to by subsurface formations；
Array WEM electromagnetic signal is carried out in oil gas ore field and the natural field electromagnetic signal of MT receives, by WEM electromagnetic signal
With the natural field electromagnetic signal combined measurement of MT and data processing inversion interpretation, the high-resolution electrically essence in oil gas ore field deep is obtained
Fine texture.
Further, the received receiver of signal uses positive north-south mode cloth pole in the method, and direct north is determined
For positive direction of the x-axis, due east direction is set to positive direction of the y-axis, and z-axis vertically downward, remembers that positive north-south electric field is Ex, positive East and West direction electric field
For Ey, the receiving instrument in 9 channels observes 3 by the 2 pairs of electric road signals (Ex and Hy) and receiver of three measuring points simultaneously
Magnetic-field component (Hx, Hy and Hz).
Further, the received receiver of signal is laid according to line direction in the method, refers to x-axis forward direction along survey line
Direction is put to trumpet, y-axis is directed toward large size line direction perpendicular to survey line.
Further, WEM electromagnetic signal and the natural field signal combined measurement of MT in the method method particularly includes: with above-mentioned
WEM emission system according to formulation working frequency table, i.e., it is same with this by certain frequency and certain time to underground Injection Current
When data collector continuous data carried out to electric road signal (Ex and Hy) and magnetic-field component (Hx, Hy and Hz) with 2.4kHz sample rate
Acquisition, and acquisition data are recorded in time.
Further, WEM electromagnetic signal and the natural field signal joint data processing of MT in the method method particularly includes: right
The data of WEM system (CLEM) acquisition, can obtain WEM data and MT low-frequency data by two kinds of data processing methods.
1, WEM active mode data processing is carried out using self-developed software, obtains the xy mode and yx mode of 0.1-300Hz
Frequency spectrum data, apparent resistivity and impedance phase.
(1) Tssplit software carries out original time series segmentation according to tranmitting frequency table；
(2) WEMPro software carries out time-frequency convert, obtains frequency domain electromagnetic field spectrum and apparent resistivity and impedance phase result；
(3) PlotWEMResult software reads that WEMPro software is handled as a result, drawing single frequency point signal spectrogram, full range
Point spectrogram and apparent resistivity curve figure.
2, to the data of CLEM system acquisition, it is convertible into MTU system MT data format, is handled using SSMT2000 software
The xy mode of 0.01-300Hz and frequency spectrum data, apparent resistivity and the impedance phase of yx mode are obtained, or is converted into ADU-07 system
System MT data format uses ProcMT software to handle frequency spectrum data, the apparent resistance of the xy mode and yx mode that obtain 0.1-300Hz
Rate and impedance phase.
It 3, can be by two groups of data of obtained WEM and MT, the i.e. frequency spectrum data of xy mode and yx mode, apparent resistivity and impedance
Phase carries out impedance decomposition, main shaft rotation and inverting according to MT data processing method respectively.
The beneficial effects of the present invention are: very low frequencies proposed by the present invention and magnetotelluric union measuring method, to make up
MT detects the deficiency weak to 1Hz Natural electromagnetic field signal in 0.1Hz, i.e., reaches number using the coverage area of WEM emission system transmitting
Thousand kilometers, artificial source's electromagnetic signal of high s/n ratio detect deep advantage using natural field signal in conjunction with magnetotelluric sounding method,
WEM electromagnetic signal and the natural field signal joint observation of MT promote MT observation quality, realize Neoproterozoic Progress of Residual Basins point in ultra-deep
Cloth precision of prediction provides scientific basis for petroleum resources assessment in the depth bounds.
Detailed description of the invention
Fig. 1 is WEM method operation principle schematic diagram；
Fig. 2 is that the coordinate of spherical hollow space waveguide modes method establishes schematic diagram；
Fig. 3 a, Fig. 3 b are the Distribution of Magnetic Field figures (cylindrical coordinate) for simulating WEM antenna when frequency is 90Hz；
Fig. 4 a, Fig. 4 b are the Distribution of Magnetic Field figure (rectangular coordinate system) for simulating WEM antenna when frequency is 90Hz；
Fig. 5 is CSAMT and WEM the simulation curve comparison diagram of model one；
Fig. 6 is CSAMT and WEM the simulation curve comparison diagram of model two；
Fig. 7 is single set reception system class MT mode layout diagram；
Fig. 8 is single set reception system along Hydrographic General Line schematic diagram；
Fig. 9 is the full-time long spectrogram of late north and south antenna transmitting observation；
Figure 10 is the final optimal duration spectrogram of late north and south antenna transmitting observation；
Figure 11 is ADU-07 system MT and CLEM system xy apparent resistivity and impedance phase correlation curve；
Figure 12 is ADU-07 system MT and CLEM system yx apparent resistivity and impedance phase correlation curve；
Figure 13 is MTU system MT and CLEM system xy mode apparent resistivity and impedance phase correlation curve；
Figure 14 is MTU system MT and CLEM system yx mode apparent resistivity and impedance phase correlation curve；
Figure 15 is 117 station ADU-07/MTU/CLEM system xy mode apparent resistivities and impedance phase correlation curve；
Figure 16 is 117 station ADU-07/MTU/CLEM system yx mode apparent resistivities and impedance phase correlation curve.
Specific embodiment
Description of specific embodiments of the present invention with reference to the accompanying drawing:
WEM method is a kind of artificial source's electromagnetic method, and principle is similar with CSAMT method to emit electromagnetism letter by artificial source
Number, the external collection of letters number of certain distance in range transmission source.It is a difference in that WEM method establishes a fixed high-power transmitting
Source, the signal covering whole nation, signal-to-noise ratio reach 10dB~20dB, had not only had the characteristics that MT method investigation depth was big, at low cost but also have people
The high feature of work source electromagnetic method (CSAMT etc.) strong antijamming capability, detection accuracy is the completely new subterranean resource detection of one kind and ground
Shake earth magnetism method and technique.
The signal of WEM method injects hundreds of Ampere currents to underground by fixed, about hundred kilometers of long earth leads
Electromagnetic wave, electromagnetism wave direction underground, along earth's surface and upwards carry out width penetrate, place different with CSAMT method is " sky wave "
In the presence of this makes WEM method become a kind of method of innovation, and " sky wave " propagates up ionosphere, then by ionospheric reflection to ground
Lower ore body, finally passes to ground by underground ore bodies.The presence of sky wave, has slowed down the rate of decay of electromagnetic wave energy, to make electricity
The penetration depth of magnetic wave is bigger, achievees the purpose that deep detects.Its working principle is as shown in Figure 1.
In the great scientific and technical infrastructure projects-" very low frequencies visit ground (WEM) engineering " of country, NW trending has been built
The transmitting antenna of 120km and north-south 80km, transmitting group power are 1000KW.It is limited by technical conditions at that time, at present its work
Working frequency range is 350Hz~0.1Hz, other observing frequencies can natural field signal make to supplement, thus ensured ultralow frequency/
The depth of exploration that Extremely Low Frequency Electromagnetic method is applied in oil-gas exploration.
Under " ionosphere " mode, the approximate calculation of electromagnetic wave field in solid layer and earth-ionosphere waveguide, for artificial
The Electromagnetic Wave Propagation that electromagnet source excites in solid layer has mature research in electromagnetic survey field.In this case, right
The influence of electromagnetic wave near field and far field, ionosphere is very micro-, therefore is the theoretical model using layered half space (containing in midair
Between, solid layer only has one layer of special circumstances) studied.Wherein enter in the mode of excitation of CSAMT and Extremely Low Frequency Electromagnetic method
The mode of excitation of work stationary source is very much like, and field source intensity, the scale of Extremely Low Frequency Electromagnetic method are much larger than CSAMT.
Ultra-low frequency electromagnetic wave can be divided into three regions in communication process, according to site at a distance from emission source: near region,
Far field and waveguide section.The ground resistivity below boundary position and transmitting antenna between three areas, emit the frequency of signal with
And the parameters such as layer height have when calculating the field strength near region and far field, the influence of displacement current can be in ionosphere and air
Ignore, therefore referred to as quasi-stability field；When previous field strength calculates in waveguide section, it is mainly used in the communications field, considers high frequency waves, because
This considers displacement current and ignores the influence for conducting electric current, therefore is called waveguide field.American scientist and Russian scientist
Trizonal division is all accepted, near region and far field line of demarcation are using 6 times of effective skin depths as standard.Have on delimiting waveguide section
Different views, American scientist Bannister is using 3 layer heights as the criteria for classifying, and Russian scientist is with quasi-stability
The amplitude difference 10% of the Ex and Hy component of field and waveguide field is standard.
The theoretical method used in the theoretical calculation and CSAMT of near region and far field field strength is consistent, in the frequency of research
Quasi-stability field method is utilized in range, is integrated using homogeneous half space HORIZONTAL ELECTRIC DIPOLE and homogeneous half space finite length conducting wire
Method.Since antenna farm resistivity and distribution situation play a very important role to ultralow frequency transmitting, so it is not only determined
The effective transmission power of antenna, and affect the electromagnetic field emissions direction of antenna.It therefore, is that there are stratiforms to antenna farm
Influence of the resistivity level distribution anisotropy (two dimension) to transmitting antenna field strength distribution and size is studied.By actual
Example is compared the calculated result in the case of electric dipole, different geology, obtains distinct methods and different geological conditions pair
Calculate the influence of field strength.
In waveguide section, the field strength distribution that extremely low frequency source is generated in waveguide section is studied, using spherical hollow space model and spherical coordinates
System and spheric-harmonic method.In the communications field, spheric-harmonic method is a mature method, when only study solid and ionosphere it
Between waveguide wave when, this is a good method, it can study global problems.But the field of localized region labyrinth
It accurately calculates relatively time-consuming, and when making approximate calculation to field, has large error, but can be used to study setting for high-power stationary source
Meter, can be how many in the signal-to-noise ratio that distance how far is entered the court with one high-power source of approximate estimation, this is also meaningful, sheet
Chapter gives such approximation, and is compared with the waveguide result of flat plate model.
Calculation method of the Extremely low frequency electronic magnetic fields in waveguide section
There are two types of the basic skills that waveguide section field strength solves: flat plate model method and spherical hollow space modelling.Flat plate model method
Ground ionosphere is regarded as the parallel flat waveguide infinitely extended, each electromagnetic field component is solved by maxwell equation group.This
Kind method is only applicable to the case where horizontal distance is less than earth radius.Since the earth is spherical shape, can also be used under spherical coordinate system
Spheric-harmonic method solution maxwell equation group is answered, and this method is suitable for the entire earth.
Spherical coordinates origin is selected in earth center, and horizontal electric dipole source is placed in θ=0, Φ=0, at r > a, and a is the earth
Radius, height of the source apart from ground are zs, and site is z apart from ground level, and horizontal electric dipole source is placed along the direction θ, tool
Body is as shown in Figure 2.
It is assumed that when humorous field be e- i ω t, then electromagnetic field meets equation in cavity spherical shape waveguide
After spherical coordinate system, each field component meets following item on the boundary in ground and ionosphere respectively on spherical surface boundary
Part
Field component is unfolded using Legendre function and spherical harmonic coefficient, and application boundary conditional (3) and formula (4) are sat in ball
Mark system, can acquire the undetermined coefficient in expansion, to acquire the solution of field component under spherical coordinates.For water in spherical hollow space waveguide
The field strength of ordinary telegram dipole solves, general to use the field strength expression for first solving vertical electric (magnetic) dipole in spherical hollow space waveguide
Formula reapplies the field strength expression formula that principle of reciprocity seeks HORIZONTAL ELECTRIC DIPOLE.Here is HORIZONTAL ELECTRIC DIPOLE in spherical hollow space waveguide
Interior each field strength expression formula.
Wherein
D=α θ, PυFor Legnedre polynomial function,Hn、HmIt is humorous for ball
Coefficient.
Wherein, Λ, G, Δ, S are respectively that the excitation factor of TM mode (under be designated as n) and TE mode (under be designated as m), height increase
Beneficial function, height normalized impedance and propagation factor；Propagation factor S=C/V-i5.49 α/f, wherein C is electromagnetic wave in vacuum
In spread speed (3.0 × 108M/s), V is electromagnetic wave propagation phase velocity, and f is wave frequency, and α is electromagnetic wave in ground electricity
Attenuation rate in absciss layer waveguide.
In ultralow frequency frequency range, electromagnetic wave can only be with n=0 mode propagation.For TM wave, 0 ≈ 0.5 of Λ works as level
When eelctric dipole component and receiving point are all located on earth surface (z=0), then G0 (0)=1, G0 (z) ≈ 1, Δ n (0)=- Δ g；
For TE wave, do not motivated in m=0 mode, i.e., ultra-low frequency electromagnetic wave can only transmit TMn=0 wave in earth-ionosphere waveguide
(TEM wave), will not occur multimode transmissions.
Above each parameter is substituted into expression formula (5) to formula (10), then can be obtained
Hr=0 (14)
Wherein
Meet condition when simultaneously | υ θ | when > > 1 and Im υ > 0, then Legendre function PυIt can make following approximate processing
It can know that its calculating for emitting field strength is decided by known ultralow frequency transmitting antenna into formula (16) from formula (11)
Three parameters below: transmitting antenna place effective conductivity, the propagation of effective ionospheric reflection height and electromagnetic wave in the waveguide
The factor (S=C/V-i5.49 α/f).If it is known that the above parameter can calculate the field strength distribution of antenna transmitting.
The field strength expression (planar waveguide or spherical hollow space waveguide) that front is derived be assuming that ionosphere and ground all
To obtain under the conditions of uniform and precipitous boundary wave guide wall, but actual ionosphere was both uneven, and boundary is not also precipitous, and
Due to the influence in earth magnetic field, ionosphere is in anisotropy, i.e., simplification waveguide modes and reality used in the above field strength derivation of equation
There is very big difference in border waveguide.In fact unexpected, these expression formulas as derived from naive model, calculated result and reality
Surveying result can reach consistent well, the proof tested in this regard.But its precondition is must to provide accurately
Antenna farm effective conductivity, the Electromagnetic Wave Propagation factor (phase velocity and attenuation rate) and the effective reflection height in ionosphere, these ginsengs
Number is can accurately to be obtained by measurement.
Since propagation effect of the ionosphere to ultralow frequency is larger, in order to improve the accuracy of the calculated results, many sections
Scholar according to the variation of ionospheric electron density establishes different models, and (such as exponential distribution model visits grace model, Ke Si model
Deng), it is then calculated with all-wave numerical integrating or shave layered approach, algorithm is all more complicated.All-wave numerical value product
Point-score and shave layered approach are established on the basis of ionosphere is longitudinally varying and laterally homogeneous.In view of ionosphere is respectively to different
Property (vertical and horizontal all change), need to study more complicated calculation method about these algorithms, be not discussed herein,
It may refer to related document.
Since ionosphere will change at any time, the measurement of transmitter site effective conductivity is also impossible to accurate (actual
Place conductivity be three-dimensional tensor form), so with it is rationalistic accurately calculate field strength at present still can not.It is taken place frequently due to extremely low
The geological structure for penetrating antenna farm is generally all more complicated, we can not accurately know that the resistivity distribution of antenna farm is (real
Border place resistivity is three-dimensional tensor form), it can only relatively accurately know the equivalent resistivity value of antenna farm, therefore in reality
Generally use Bannister approximation method in the field strength theoretical calculation of border (HORIZONTAL ELECTRIC DIPOLE adds a correction term).The method exists
It is also applied in the place resistivity verifying work of U.S.'s ultralow frequency antenna.Specific formula for calculation is following (under cylindrical coordinate)
Wherein, I is antenna emission current, and L is antenna length, propagation constant γ e ≈ (i ω μ0σe)1/2,σeFor transmitting antenna
The effective conductivity of lower section, effective skin depth δ e ≈ (2/ ω μ0σe)1/2, μ0=4 π × 10-7H/m.Using propagation factor relationship
Formula S=C/V-i5.49 α/f derives the succinct waveguide section magnetic field of comparison in which can be convenientTheoretical calculation approximate formula,
This formula is widely used in the Distribution of Magnetic Field prediction of ultralow frequency transmitting antenna, and is verified during actual measurement.
Wherein, Idl is electric dipole moment (Am)；F is working frequency (Hz)；hiFor the effective reflection height (m) in ionosphere；σeFor
Antenna farm effective conductivity (S/m)；ρ is great-circle distance (m)；α is waveguide attenuation rate (NP/m), when attenuation rate is with dB/Mm
When for unit, then αMm=α/8.686；αeFor earth radius 6.37 × 106(m)；C is the free space light velocity (m/s)；V is electromagnetism
The spread speed (m/s) of wave in the waveguide.
It can be seen that, more 3 parameters are wanted in the calculating of the field strength calculating ratio near region and far field of waveguide section, i.e., from formula (20)
The effective reflection height h in ionospherei, spread speed v and propagation attenuation rate α in electromagnetism sonic wave guide.This 3 parameters all with ionosphere
It is related.Ionosphere plays the role of the propagation of ultra-low frequency electromagnetic wave in the waveguide very important.Therefore, to waveguide section field strength
The calculating of distribution has actually become calculating of the ionosphere to ultra-low frequency electromagnetic wave propagation effect.
Rig for model test whole nation field intensity map
Due to the effect of earth magnetism, the attenuation rate and phase velocity of electromagnetic wave are related with the direction of propagation, from west eastwards propagation attenuation compared with
It is small, on the contrary decaying is larger, and north-south is placed in the middle.It is obtained according to mid latitudes actual measurement data, in 300Hz, the two difference
1.5~2dB/Mm；In 100Hz, the two differs 0.5dB/Mm.It therefore, will be according to electromagnetic wave in the calculating of field strength distribution theory
The direction of propagation, with due regard to attenuation rate problem.When calculating the radio field intensity of 90Hz frequency westwards propagated herein, simply adopt
With in the attenuation rate that G&G theoretical calculation obtains plus 0.5dB/Mm.
In summary it analyzes, rig for model test 90Hz transmitting can be calculated according to the position of rig for model test in we
The field strength distribution isogram of frequency in China.Wherein, Fig. 3 a, Fig. 3 b be cylindrical coordinate under magnetic field H ρ andIt is equivalent
Figure, Fig. 4 a, Fig. 4 b are magnetic field Hx and Hy isopleth map under rectangular coordinate system.Institute's target field strength values may be with practical field strength in figure
Have certain error, but it reflects WEM signal strength in the distribution situation in the whole nation substantially, can be arranged for work later provide according to
According to.
WEM simulation curve feature:
It is whether consistent with MT and CSAMT forward modelling result to understand WEM forward modelling tracing pattern feature, thus
Homogeneous half space and three layers of geoelectric cross section forward modeling are carried out.
Model one
First layer resistivity, 100 Ω m, thickness 500m, the second layer resistivity is 1000 Ω m, and emitter is away from AB
120km, emission current 120A, frequency range 0.003-350Hz, transmitting-receiving away from for 2km, 20km, 50km, 100km, 150km,
250km,400km,700km,1500km.CSAMT and WEM forward modeling result is as shown in Figure 5.
CSAMT, WEM curve that Fig. 5 is shown can reflect 100 Ω m of the first layer resistivity of superficial part greater than 100Hz,
The apparent resistivity and impedance phase of CSAMT all shows the obvious area get Fei Bo curvilinear characteristic away from 2km~20km in transmitting-receiving, i.e. view electricity
Resistance rate is reduced with frequency and is gradually increased, and phase gradually tends to 0；Receive and dispatch away from be greater than 150km after apparent resistivity and phase gradually
The electrical property feature for tending to 1000 Ω m of inverting Deep Electrical layer, when transmitting-receiving is away from for 250km, curve and MT curve are completely the same,
Show to receive and dispatch herein away from for complete wave area feature.When considering ionosphere, WEM apparent resistivity and phase curve feature and variation
Curve is almost the same with CSAMT, in transmitting-receiving away from from closely still depositing to remote or even the distant place 150km apparent resistivity and phase curve
In the false extreme value phenomenon of transition region.
CSAMT, WEM curve that Fig. 6 is shown are substantially similar to Fig. 5, can reflect superficial part first layer resistance being greater than 100Hz
The apparent resistivity and impedance phase of rate 100 Ω m, CSAMT all show the obvious area get Fei Bo curve away from 2km~20km in transmitting-receiving
Feature；Receive and dispatch away from be greater than 150km after apparent resistivity and phase can just show 10 Ω m of low resistivity layer, be greater than 150km gradually
The electrical property feature for tending to 1000 Ω m of inverting Deep Electrical layer, when transmitting-receiving is away from for 250km, curve and MT curve are completely the same,
Show to receive and dispatch herein away from for complete wave area feature.
The result shows that, it is due to being greater than 250km at a distance in emission source in the case where ionosphere acts on from two above forward modeling
Plane wave, apparent resistivity and phase and MT curve are completely the same, are proved in practical field inspection with this, far from emission source
It can be observed when 250km with the device that MT is observed.
Data acquisition modes:
Positive north-south class MT mode cloth pole can be used in receiver, sees Fig. 7, and direct north is set to positive direction of the x-axis, positive east
To positive direction of the y-axis is set to, z-axis vertically downward, remembers that positive north-south electric field is Ex, positive East and West direction electric field is Ey at this time.Receiving instrument
3 magnetic-field components by the 3 pairs of electric road signals and receiver of three measuring points can be observed simultaneously.
It can also be laid according to line direction, x-axis forward direction is made to be directed toward small size point direction along survey line, y-axis refers to perpendicular to survey line
To large size line direction, cloth pole mode is shown in Fig. 8.
3 measuring points can be measured simultaneously to the every set equipment of WEM, intermediate measuring point measures the electric field and three components of two components
Magnetic field, the measuring point of two sides only measures the electric field of two components, and the magnetic field of two sides depth measurement point uses intermediate measuring point when data processing
Magnetic field.
2, tranmitting frequency launch time is designed
The length of time of WEM tranmitting frequency affects observation quality, is compared with the spectrum intensity of measured data, determines actual measurement
The launch time of tranmitting frequency table.Compared with molybdenum ore survey area is died young in Hebei Renqiu oil field survey area and Inner Mongol Cao Si, river Dongming Yue Xia structure
It is closer from emission source to make survey offset, preferable signal may can be also obtained with shorter transmitting duration, to improve efficiency.
Frequency meter is double antenna transmitting, is emitted daytime with East and West direction antenna, is emitted at night with north-south antenna.This stage
There are two purposes, first is that measuring on design measuring point, second is that further determining that transmitting duration.Select Cao Si die young Molybdenum Mining Area connection
Launching frequency and duration when testing are debugged to be tested, frequency point used and transmitting duration are shown in Table 1 secondary series and third column, root
1 the 4th column are shown in Table according to the optimal duration that signal-to-noise ratio counts.
Table 1 is tranmitting frequency table, with Cao Si die young Molybdenum Mining Area united test when the obtained spectrogram of transmitting duration used see figure
9, with final optimal duration, 1 the 5th column are shown in Table, obtained spectrogram is shown in Figure 10.
1 tranmitting frequency table of table
Although can be seen that the transmitting duration for shortening each frequency point from two figures, the intensity of signal relative to noise according to
It is so very strong, the value of available quantization is counted by signal-to-noise ratio, is shown in Table the signal-to-noise ratio statistical form of 2 two kinds of transmitting durations.By right
The spectrogram and signal-to-noise ratio for emitting duration than two kinds can be seen that is died young duration (in table 2 the 3rd column) transmitting of united test with Cao Si
25 frequency points, launch time summation is 514 minutes, and is emitted with final optimal duration (the 5th column in table 2), and launch time is total
Be 336 minutes, in comparison, launch time was shorten to 36 minutes 5 hours by original 34 minutes 8 hours, and the big step of efficiency mentions
Height, while signal-to-noise ratio is still very high.
Table 2
The reception system (CLEM) of WEM instrument and equipment can carry out WEM data with 2.4kHz sample rate and MT data aggregate is adopted
Collection, flow chart of data processing:
(1) to the data of domestic CLEM system acquisition, carrying out WEM using WEM engineering resource detection project self-developed software has
Source module data processing.
(a) Tssplit software carries out original time series segmentation according to tranmitting frequency table；
(b) WEMPro software carries out time-frequency convert, obtains frequency domain electromagnetic field spectrum and apparent resistivity and impedance phase result；
(c) PlotWEMResult software reads that WEMPro software is handled as a result, drawing single frequency point signal spectrogram, full range
Point spectrogram and apparent resistivity curve figure.
(2) to the data of domestic CLEM system acquisition, it is convertible into MTU system MT data format, it is soft using SSMT2000
Part processing forms MT data, or is converted into ADU-07 system MT data format, forms MT data using ProcMT software processing.
Acquire whether data use WEM and MT data aggregate to measure to verify the reception system (CLEM) of WEM instrument and equipment, once
Comparative test was done, i.e., CLEM system and Canada MTU system, German AD U-07 system is synchronized same measuring point data and adopted
Collection compares the result of three sets of systems of analysis.
Since MTU system and ADU-07 system not can be carried out WEM data acquisition and processing (DAP), the MT number of three kinds of systems is only provided
According to comparing result, i.e., the data conversion that arrives CLEM system acquisition at MTU system and ADU-07 system format time series data, then
It is handled to obtain MT data result with corresponding software.Here the comparing result of several typical positions is only shown.Wherein CLEM system
Receiver is DRU series, and hereafter the DRU in graph mark indicates CLEM measuring results.
Figure 11-Figure 12 is the MT Comparative result curve of the ADU-07 system and CLEM system at 87 stations (4340m), Tu11Shi
For xy to apparent resistivity and impedance phase correlation curve, Figure 12 is yx to apparent resistivity and impedance phase correlation curve.In figure
ProcMT expression is handled using German Metronix company ProcMT software, and red line is ADU-07 system MT data processing knot
Fruit, blue line are from CLEM system WEM acquisition data conversion into the processing result after MT data format.It can from Figure 11-Figure 12
The MT apparent resistivity and impedance phase curves of CLEM system are rounder and more smooth out, on most of frequency point, CLEM system and ADU-07
System is coincide preferably, and especially yx coincide fine to result.
Figure 13-Figure 14 is the MT Comparative result curve of MTU system and CLEM system on 125 stations (6250m), and Figure 13 is xy mould
Formula apparent resistivity and impedance phase correlation curve, Figure 14 are yx mode apparent resistivity and impedance phase correlation curve.SSMT in figure
Expression is handled using the SSMT2000 software of Canadian phoenix company, and red line is the data of CLEM system WEM type collection
Change into MT data format post-processing as a result, blue line is the processing result of CLEM system MT type collection data, green line is MTU system
System MT data processed result.It can be seen that the CLEM system MT processing result of WEM mode and MT type collection is equal from Figure 13-Figure 14
It coincide with MTU system MT processing result fine.
Figure 15-Figure 16 is that the MT Comparative result of ADU-07 system, MTU system and CLEM system on the 117th station (5850m) is bent
Line, Figure 15 are xy mode apparent resistivity and impedance phase correlation curve, and Figure 16 is yx mode apparent resistivity and impedance phase comparison
Curve.ProcMT expression is handled using the ProcMT software of German Metronix company in figure, and SSMT is indicated using plus taken
The SSMT2000 software of big phoenix company is handled, and red line is ADU-07 system MT data processed result, and blue line is CLEM system
The data of system WEM type collection change into after MT data format with the processing of ProcMT software as a result, green line is CLEM system WEM mould
The data of formula acquisition change into after MT data format with the processing of SSMT2000 software as a result, yellow line is MTU system MT data processing
As a result.It can be seen that four kinds of results of frequency point of 1Hz or more are identical from Figure 15-Figure 16, low-frequency range ProcMT software processing knot
Fruit and SSMT2000 software processing result are variant, think it is caused by two software low frequency algorithms are different.
From Figure 11-Figure 16 it is known that the data that the reception system device (CLEM) of WEM system acquires, which are passed through, is transformed into ADU-
07 system, MTU System Data Format, then MT data and curve can get by ADU-07 system, MTU system processing software respectively,
Its curve is rounder and more smooth, coincide preferably with ADU-07 system, the MT result of MTU system, shows that the data of CLEM system acquisition can be made
For MT initial data, effect is effectively reliable.Illustrate that CLEM system acquisition device can realize MT data while observing WEM data
Measurement.
The above is a preferred embodiment of the present invention, it is noted that for those skilled in the art
For, without departing from the principles of the present invention, it can also make several improvements and retouch, these improvements and modifications
It should be regarded as protection scope of the present invention.
Claims (4)
1. a kind of very low frequencies and magnetotelluric union measuring method, the method are as follows:
It upwardly propagates to form sky wave using the electromagnetic wave that the signal emitting-source of WEM method generates, sky wave propagation is to ionosphere, then by electricity
Absciss layer is reflected into underground medium, finally travels to ground by underground medium；
Array WEM electromagnetic signal is carried out in oil gas ore field and the natural field signal of MT receives, it is natural by WEM electromagnetic signal and MT
Field signal combined measurement and data processing inversion interpretation obtain the high-resolution electrical fine structure in oil gas ore field deep.
2. very low frequencies as described in claim 1 and magnetotelluric union measuring method, which is characterized in that observed in the method
Device uses positive north-south mode cloth pole, direct north is set to positive direction of the x-axis, due east direction is set to positive direction of the y-axis, and z-axis is hung down
Straight to remember positive north-south electric field downwards for Ex, positive East and West direction electric field is Ey, and a set of receiving instrument observes the electric road of three measuring points simultaneously
Magnetic-field component (Hx, Hy and Hz) by signal (Ex and Ey) and receiver.
3. very low frequencies as described in claim 1 and magnetotelluric union measuring method, which is characterized in that observed in the method
Device can also be laid according to line direction, so that x-axis forward direction is directed toward small size point direction along survey line, y-axis is directed toward big perpendicular to survey line
Number line direction.
4. very low frequencies as described in claim 1 and magnetotelluric union measuring method, which is characterized in that WEM in the method
Electromagnetic signal and the natural field signal combined measurement of MT and data processing.
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Cited By (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109407160A (en) * | 2018-12-19 | 2019-03-01 | 中国科学院地质与地球物理研究所 | A method of D integral pin-fin tube is carried out based on WEM vector finite element method |
| CN110068873A (en) * | 2019-05-10 | 2019-07-30 | 成都理工大学 | A kind of magnetotelluric D integral pin-fin tube method based on spherical coordinate system |
| CN110133727A (en) * | 2019-06-10 | 2019-08-16 | 周丹 | Ultra-deep oil and gas reservoir high-precision electromagnetism spectrum detection method |
| CN111126793A (en) * | 2019-12-05 | 2020-05-08 | 中国船舶重工集团公司第七研究院 | Landslide risk assessment method based on ultralow frequency electromagnetic wave |
| CN111290027A (en) * | 2020-03-09 | 2020-06-16 | 中国科学院地质与地球物理研究所 | Deep resource electromagnetic detection method combining mobile source and fixed source |
| CN112285790A (en) * | 2020-03-30 | 2021-01-29 | 中国科学院地质与地球物理研究所 | Method and device for determining attenuation coefficient of electromagnetic wave field and medium |
| CN112833853A (en) * | 2020-12-29 | 2021-05-25 | 中国船舶重工集团有限公司第七一0研究所 | Extremely-low-frequency through-earth electromagnetic signal source direction finding method |
| CN112946765A (en) * | 2020-12-29 | 2021-06-11 | 中国船舶重工集团公司第七研究院 | Impedance tensor calculation method of WEM method |
| CN117741776A (en) * | 2024-02-19 | 2024-03-22 | 山东大学 | Artificial source frequency domain electromagnetic exploration method and system containing natural source reference |
| CN117741776B (en) * | 2024-02-19 | 2024-05-03 | 山东大学 | Artificial source frequency domain electromagnetic exploration method and system containing natural source reference |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20100194394A1 (en) * | 2006-12-06 | 2010-08-05 | Technoimaging, Llc | Systems and methods for remote electromagnetic exploration for mineral and energy resources |
| CN103091718A (en) * | 2011-11-04 | 2013-05-08 | 中国船舶重工集团公司第七研究院 | Method of using extremely low frequency marine electromagnetic method to conduct marine oil and gas resources exploration |
| RU2012102876A (en) * | 2012-01-27 | 2013-08-10 | Федеральное бюджетное учреждение "12 Центральный научно-исследовательский институт Министерства обороны Российской Федерации" | METHOD OF SUBSURFACE SENSING AT MIDDLE LATITIES USING RADIATION OF HEATED IONOSPHERIC ELECTRONS |
| CN105807326A (en) * | 2016-04-11 | 2016-07-27 | 中国科学院地质与地球物理研究所 | System and method for deep exploration by means of sky waves |
| CN105807325A (en) * | 2014-12-31 | 2016-07-27 | 中国船舶重工集团公司第七研究院 | Frequency domain aviation extremely low frequency electromagnetic method |
-
2018
- 2018-09-27 CN CN201811128746.5A patent/CN109031432A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20100194394A1 (en) * | 2006-12-06 | 2010-08-05 | Technoimaging, Llc | Systems and methods for remote electromagnetic exploration for mineral and energy resources |
| CN103091718A (en) * | 2011-11-04 | 2013-05-08 | 中国船舶重工集团公司第七研究院 | Method of using extremely low frequency marine electromagnetic method to conduct marine oil and gas resources exploration |
| RU2012102876A (en) * | 2012-01-27 | 2013-08-10 | Федеральное бюджетное учреждение "12 Центральный научно-исследовательский институт Министерства обороны Российской Федерации" | METHOD OF SUBSURFACE SENSING AT MIDDLE LATITIES USING RADIATION OF HEATED IONOSPHERIC ELECTRONS |
| CN105807325A (en) * | 2014-12-31 | 2016-07-27 | 中国船舶重工集团公司第七研究院 | Frequency domain aviation extremely low frequency electromagnetic method |
| CN105807326A (en) * | 2016-04-11 | 2016-07-27 | 中国科学院地质与地球物理研究所 | System and method for deep exploration by means of sky waves |
Non-Patent Citations (7)
| Title |
|---|
| JANIS GALEJS: "《TERRESTRIAL PROPAGATION OF LONG ELECTROMAGNETIC WAVES》", 31 December 1972, PERGAMON PRESS * |
| MASAHIRO ICHIKI ,ET AL.: "Magnetotelluric investigations for the seismically active area in Northern Miyagi Prefecture, northeastern Japan", 《EARTH PLANET SPACE》 * |
| PETER R. BANNISTER,ET AL.: "Results of the August 1972 Wisconsin Test Facility Effective Earth Conductivity Measurements", 《JOURNAL OF GEOPHYSICAL RESEARCH》 * |
| ROBERT A. SAINATI,ET AL.: "Application of Magnetotelluric Techniques at Extremely Low Frequency (ELF) Eor Sanguine Transmitting Antenna Site Characterization", 《IEEE TRANSACTIONS ON COMMUNICATIONS》 * |
| 卓贤军 等，: "极低频探地（WEM）工程", 《中国工程科学》 * |
| 张淑玲 等，: "大功率源无线电磁探测信息处理技术研究", 《船舶电子工程》 * |
| 聂松 等，: "大地电磁磁场数据子库", 《工程地球物理学报》 * |
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