CN104749643A - CSAMT (controlled source audio frequency magneto telluric) measuring method and device used for electromagnetic interference areas - Google Patents

Abstract

The invention relates to a CSAMT (controlled source audio frequency magneto telluric) measuring method and device used for electromagnetic interference areas. The CSAMT measuring method includes: determining whether a to-be-measured area is an electromagnetic interference area or not; acquiring a CSAMT measuring result of the to-be-measured area according to CSAMT horizontal electric field component of the to-be-measured area when the to-be-measured area is an electromagnetic interference area. The CSAMT measuring device comprises an electromagnetic interference area determining unit and a measuring result acquiring unit, the electromagnetic interference area determining unit is used for determining whether the to-be-measured area is an electromagnetic interference area, and the measuring result acquiring unit is used for acquiring the CSAMT measuring result of the to-be-measured area according to the CSAMT horizontal electric field component when the to-be-measured area is an electromagnetic interference area. By the CSAMT measuring method and device, accurate CSAMT measuring results can be acquired in areas severe in electromagnetic interference.

Description

A kind of CSAMT measuring method for electromagnetic interference (EMI) area and device

Technical field

The present invention relates to electromagnetic technology field, be specifically related to a kind of CSAMT measuring method for electromagnetic interference (EMI) area and device.

Background technology

In recent years, controlled-source audiomagnetotellurics method (controlled-source audio-frequencymagneto-telluric, CSAMT) in geological information amount, signal intensity, operating efficiency and detection accuracy etc., show many superiority, make CSAMT technology more and more receive the concern of people.CSAMT technology is developed by magnetotelluric method (MT), its application of having succeeded in fields such as ore exploration, oil-gas exploration, deep-marine-environment investigation, underground water and underground heat researchs at present.Owing to can describe geologic body shape and position, CSAMT can also be applied to mineral structure investigation.In addition, CSAMT technology also can be applicable to bore front geofault location and ponding Mined-Out Areas.

In theory, the metering system of controlled-source audiomagnetotellurics method as shown in Figure 1A.As shown in Figure 1A, A, B are the emitting electrode of two ground connection, and both are connected by wire, and C, D, E, F are four identical electric field reception electrode, and 1,2,3 is three identical magnetic field receiving transducers.The electric current that emissive source is constantly changed to underground transmission frequency by emitting electrode and wire, during measurement, corresponding road, a magnetic field, each electric field road, often measures the horizontal electric field component data of a measuring point, just must measure the horizontal component ofmagnetic field data of this point.Like this can according to the plane wave impedance of measured horizontal component of electric field and horizontal magnetic field data computation and measurement point position:

Formula one: $Z_{\mathrm{xy}}=\frac{E_x}{H_y}=\sqrt{\mathrm{i\ω}{\mathrm{\μ}}_0\mathrm{\ρ}}$

In formula, Z _xyrepresent wave impedance, E _xrepresent horizontal electric field component amplitude, H _yrepresent horizontal component ofmagnetic field amplitude, ω represents signal circular frequency, and ρ represents resistivity, μ ₀represent permeability of vacuum.

Ratio (Cagniard) apparent resistivity can be obtained by formula one:

Formula two: ${\mathrm{\ρ}}_{\mathrm{\ω}}^{E_x/H_y}=\frac{1}{\mathrm{\ω}{\mathrm{\μ}}_0}{\left|\frac{E_x}{H_y}\right|}^2$

In formula, represent ratio (Cagniard) apparent resistivity.

From formula two: when resistivity value is less, electric field component need be made to keep less, or frequency values keep larger; On the contrary, when resistivity value is larger, electric field component need be made to keep comparatively large, or frequency values keep less.Therefore, the low-frequency electromagnetic wave propagated in low-resistance the earth, carries more magnetic-field component; The frequency electromagnetic waves propagated in high resistant the earth, carries more electric field component.

But, in actual applications, in order to increase work efficiency, most unit all have employed improvement type CSAMT metering system as shown in Figure 1B when carrying out controlled-source audiomagnetotellurics sounding work, namely when measuring, measure the horizontal component of electric field data of 3 measuring points simultaneously, and only observe the horizontal magnetic field data of 1 measurement point, when data process, think that the horizontal magnetic field of 3 measurement points is identical, according to the horizontal component of electric field data of formula dual-purpose 3 measuring points divided by the horizontal magnetic field data of 1 measurement point, the approximate apparent resistivity value obtaining 3 measuring points.

The disadvantage of this improvement type of current employing CSAMT metering system is: the numerical value of the magnetic track that each horizontal component of electric field is surveyed corresponding to road should be different, namely the magnetic field corresponding to each electric field component should be different, but only measuring a magnetic field value here, is obviously inappropriate.On the other hand, field signal is natively very faint, if survey district when there is larger interference, the error measuring magnetic field is all brought in result, then by square making error more amplify, this just causes very large impact to measurement result.Thus, the measurement result that obtains compared with Qiang Ce district for electromagnetic interference (EMI) of existing CSAMT measuring technique is accurate relatively not.

In addition, although when Electric and magnetic fields is subject to same disturbance, ratio apparent resistivity can remove interference.But the interference that is subject to of Electric and magnetic fields is not identical under many circumstances, and ratioing technigue will worsen observation quality.In reality exploration, can run into various different complex environment, the complicacy of measurement environment can cause different impact to each component of each component of electric field and magnetic field.

Summary of the invention

The invention provides a kind of CSAMT measuring method for electromagnetic interference (EMI) area and device, its objective is the inaccurate problem of measurement result solving existing CSAMT measuring technique and obtain compared with Qiang Ce district for electromagnetic interference (EMI).

In order to realize foregoing invention object, the technical scheme that the present invention takes is as follows:

For the CSAMT measuring method in electromagnetic interference (EMI) area, described CSAMT measuring method comprises: determine whether region to be measured is electromagnetic interference (EMI) area; And when described region to be measured is electromagnetic interference (EMI) area, obtain the CSAMT measurement result in described region to be measured according to the CSAMT horizontal electric field component in described region to be measured.

Preferably, described CSAMT measurement result comprises and utilizes the CSAMT horizontal electric field component in described region to be measured to carry out the apparent resistivity value calculated.

Preferably, described apparent resistivity value obtains according to following formulae discovery: wherein, r is the distance between field source to measuring point, l _aBfor the distance between transmitting electrode, l _mNfor the distance between receiving electrode, Δ V is the voltage between potential electrode M, N, Δ V=E _xl _mN, E _xfor horizontal electric field component amplitude, and I is for sending electric current.

Preferably, describedly determine that whether region to be measured is that the step in electromagnetic interference (EMI) area comprises: the multiple measuring points determining described region to be measured; At each measuring point of described multiple measuring point, measure horizontal electric field component and horizontal component ofmagnetic field respectively; And according to the horizontal electric field component of described multiple measuring point and horizontal component ofmagnetic field, determine horizontal electric field component error and the horizontal component ofmagnetic field error of described multiple measuring point, and when described horizontal electric field component error is less than described horizontal component ofmagnetic field error, described region to be measured is defined as electromagnetic interference (EMI) area.

Preferably, described CSAMT measuring method also comprises: according to horizontal electric field component and the horizontal component ofmagnetic field of described multiple measuring point, obtains horizontal electric field component curve and the horizontal component ofmagnetic field curve of described multiple measuring point under log-log coordinate system; And when curve quality higher than described horizontal component ofmagnetic field curve of the curve quality of described horizontal electric field component curve, judge that described horizontal electric field component error is less than described horizontal component ofmagnetic field error.

Preferably, described CSAMT measuring method also comprises: calculate described horizontal electric field component curve in the first slope of each measuring point and the first mean value of each the first slope and the first standard deviation, and the measuring point difference of the first slope and described first mean value being greater than described first standard deviation is defined as first departs from measuring point; Calculate described horizontal component ofmagnetic field curve in the second slope of each measuring point and the second mean value of each the second slope and the second standard deviation, and the measuring point difference of the second slope and described second mean value being greater than described second standard deviation is defined as second departs from measuring point; And when described first number departing from measuring point be less than described second depart from the number of measuring point time, judge the curve quality of the curve quality of described horizontal electric field component curve higher than described horizontal component ofmagnetic field curve.

For the CSAMT measurement mechanism in electromagnetic interference (EMI) area, described CSAMT measurement mechanism comprises: electromagnetic interference (EMI) area determining unit, and it is for determining whether region to be measured is electromagnetic interference (EMI) area; And measurement result obtains unit, it is for when described region to be measured is electromagnetic interference (EMI) area, obtains the CSAMT measurement result in described region to be measured according to the CSAMT horizontal electric field component in described region to be measured.

Preferably, described measurement result obtains apparent resistivity value that unit is used for utilizing the CSAMT horizontal electric field component in described region to be measured to carry out the calculating CSAMT measurement result as described region to be measured.

Preferably, described measurement result obtains unit for obtaining apparent resistivity value according to following formulae discovery: wherein, r is the distance between field source to measuring point, l _aBfor the distance between transmitting electrode, l _mNfor the distance between receiving electrode, Δ V is the voltage between potential electrode M, N, Δ V=E _xl _mN, E _xfor horizontal electric field component amplitude, and I is for sending electric current.

Preferably, described electromagnetic interference (EMI) area determining unit is used for: the multiple measuring points determining described region to be measured; At each measuring point of described multiple measuring point, measure horizontal electric field component and horizontal component ofmagnetic field respectively; And according to the horizontal electric field component of described multiple measuring point and horizontal component ofmagnetic field, determine horizontal electric field component error and the horizontal component ofmagnetic field error of described multiple measuring point, and when described horizontal electric field component error is less than described horizontal component ofmagnetic field error, described region to be measured is defined as electromagnetic interference (EMI) area.

Preferably, described electromagnetic interference (EMI) area determining unit is used for: according to horizontal electric field component and the horizontal component ofmagnetic field of described multiple measuring point, obtains horizontal electric field component curve and the horizontal component ofmagnetic field curve of described multiple measuring point under log-log coordinate system; And when curve quality higher than described horizontal component ofmagnetic field curve of the curve quality of described horizontal electric field component curve, judge that described horizontal electric field component error is less than described horizontal component ofmagnetic field error.

Preferably, described electromagnetic interference (EMI) area determining unit is used for: calculate described horizontal electric field component curve in the first slope of each measuring point and the first mean value of each the first slope and the first standard deviation, and the measuring point difference of the first slope and described first mean value being greater than described first standard deviation is defined as first departs from measuring point; Calculate described horizontal component ofmagnetic field curve in the second slope of each measuring point and the second mean value of each the second slope and the second standard deviation, and the measuring point difference of the second slope and described second mean value being greater than described second standard deviation is defined as second departs from measuring point; And when described first number departing from measuring point be less than described second depart from the number of measuring point time, judge the curve quality of the curve quality of described horizontal electric field component curve higher than described horizontal component ofmagnetic field curve.

Compared to the prior art the present invention, has following beneficial effect:

CSAMT measuring method for electromagnetic interference (EMI) area of the present invention and device, can obtain CSAMT measurement result relatively accurately for the area that electromagnetic interference (EMI) is serious; The apparent resistivity precision calculated only depends on the accuracy of electric field component, and does not affect by magnetic-field component; When for inferring subsurface geologic structures and distribution in electromagnetic interference (EMI) area, can obtain and infer more accurately and analysis result.

Accompanying drawing explanation

Figure 1A is the measuring equipment structural representation of existing CSAMT measuring technique;

Figure 1B is the measuring equipment structural representation of improvement type CSAMT measuring technique;

Fig. 2 is the process flow diagram of an example of a kind of CSAMT measuring method for electromagnetic interference (EMI) area of the embodiment of the present invention;

Fig. 3 is the block diagram of the CSAMT measurement mechanism for electromagnetic interference (EMI) area of embodiments of the invention;

Fig. 4 is the horizontal electric field component curve obtained in an application example of the present invention;

Fig. 5 is the horizontal component ofmagnetic field curve obtained in an application example of the present invention;

Fig. 6 is the apparent resistivity that utilizes prior art to obtain in an application example of the present invention and the curve map utilizing the apparent resistivity obtained for the CSAMT measuring method in electromagnetic interference (EMI) area of the present invention.

Embodiment

Clearly understand for making goal of the invention of the present invention, technical scheme and beneficial effect, below in conjunction with accompanying drawing, embodiments of the invention are described, it should be noted that, when not conflicting, the embodiment in the application and the feature in embodiment can combination in any mutually.

The embodiment provides a kind of CSAMT measuring method for electromagnetic interference (EMI) area, the method comprises: determine whether region to be measured is electromagnetic interference (EMI) area; And when described region to be measured is electromagnetic interference (EMI) area, obtain the CSAMT measurement result in described region to be measured according to the CSAMT horizontal electric field component in described region to be measured.

Fig. 2 shows the process flow diagram of an example process of a kind of CSAMT measuring method for electromagnetic interference (EMI) area according to the embodiment of the present invention.As shown in Figure 2, after this treatment scheme starts, first perform step S110.

In step s 110, determine whether region to be measured is electromagnetic interference (EMI) area: if so, then continue to perform step S120; Otherwise, can step S130 be performed, or, also can terminate this flow process.

In the step s 120, the CSAMT measurement result in region to be measured is obtained according to the CSAMT horizontal electric field component in region to be measured.Then, this flow process is terminated.

If perform step S130, then in step s 130, which, the CSAMT measurement result in region to be measured is obtained according to mode same as the prior art, such as, utilize the CSAMT horizontal electric field component in region to be measured and horizontal component ofmagnetic field to obtain its CSAMT measurement result (such as adopting formula two mentioned above to calculate apparent resistivity, as CSAMT measurement result).Then, this flow process is terminated.

Preferably, determine in step S110 that whether region to be measured is that the process in electromagnetic interference (EMI) area can realize in the following manner: in this region to be measured, determine multiple measuring point (such as 3 or more), wherein said multiple measuring point can be evenly distributed on region to be measured, also can rule of thumb or test method arrange; At each measuring point of described multiple measuring point, measure horizontal electric field component and horizontal component ofmagnetic field respectively, the concrete grammar wherein measuring horizontal electric field component and horizontal component ofmagnetic field can realize by CSAMT collecting method conventional in prior art; Then according to the respective horizontal electric field component of described multiple measuring point and horizontal component ofmagnetic field, determine horizontal electric field component error and the horizontal component ofmagnetic field error of described multiple measuring point, if the horizontal electric field component error of described multiple measuring point is less than its horizontal component ofmagnetic field error, then this region to be measured is defined as electromagnetic interference (EMI) area.

Preferably, in step s 110, according to the horizontal electric field component of described multiple measuring point and horizontal component ofmagnetic field, under log-log coordinate system, horizontal electric field component curve and the horizontal component ofmagnetic field curve of described multiple measuring point can be obtained.

If the curve quality of the horizontal electric field component curve of described multiple measuring point is higher than the curve quality of its horizontal component ofmagnetic field curve, then judge that its horizontal electric field component error is less than its horizontal component ofmagnetic field error, and then be electromagnetic interference (EMI) area by this regional determination to be measured; If the curve quality of the horizontal electric field component curve of described multiple measuring point is less than or equal to the curve quality of its horizontal component ofmagnetic field curve, then judge that its horizontal electric field component error is more than or equal to its horizontal component ofmagnetic field error, therefore this region to be measured is not electromagnetic interference (EMI) area.

Preferably, the curve quality of the horizontal electric field component curve of described multiple measuring point can be calculated in the following manner: the slope calculating horizontal electric field component curve each measuring point in described multiple measuring point of described multiple measuring point, as the first slope; Calculate mean value and the standard deviation of the first slope of each measuring point in described multiple measuring point, respectively as the first mean value and the first standard deviation; For each measuring point in described multiple measuring point, calculate the first slope of this measuring point and the difference of the first mean value, if this difference is greater than the first standard deviation, then this measuring point is defined as first and departs from measuring point; Statistics first departs from the number of measuring point, for reflecting the curve quality of horizontal electric field component curve, wherein, first to depart from the number of measuring point more, represent that the curve quality of horizontal electric field component curve is poorer, and first to depart from the number of measuring point fewer, represent that the curve quality of horizontal electric field component curve is better.

Similarly, the curve quality of the horizontal component ofmagnetic field curve of described multiple measuring point can be calculated in the following manner: the slope calculating horizontal component ofmagnetic field curve each measuring point in described multiple measuring point of described multiple measuring point, as the second slope; Calculate mean value and the standard deviation of the second slope of each measuring point in described multiple measuring point, respectively as the second mean value and the second standard deviation; For each measuring point in described multiple measuring point, calculate the second slope of this measuring point and the difference of the second mean value, if this difference is greater than the second standard deviation, then this measuring point is defined as second and departs from measuring point; Statistics second departs from the number of measuring point, for reflecting the curve quality of horizontal component ofmagnetic field curve, wherein, second to depart from the number of measuring point more, represent that the curve quality of horizontal component ofmagnetic field curve is poorer, and second to depart from the number of measuring point fewer, represent that the curve quality of horizontal component ofmagnetic field curve is better.

Then, judge whether the first number departing from measuring point is less than the number that second departs from measuring point: the curve quality of curve quality higher than horizontal component ofmagnetic field curve if so, then judging horizontal electric field component curve; Otherwise then the curve quality of horizontal electric field component curve is less than or equal to the curve quality of horizontal component ofmagnetic field curve.

If the curve quality of horizontal electric field component curve is better than the curve quality of horizontal component ofmagnetic field curve, illustrate that horizontal electric field component is less by electromagnetic interference influence, and horizontal component ofmagnetic field is large by electromagnetic interference influence.In this case, if use traditional ratio apparent resistivity method, result of calculation can by magnetic field data severe exacerbation.Therefore, in electromagnetic interference (EMI) area, CSAMT measuring method of the present invention is adopted to carry out CSAMT measurement, namely, adopt horizontal electric field component carry out data processing and explanation (such as adopt hereafter by the formula nine of description to calculate apparent resistivity, as CSAMT measurement result), measurement result can be made comparatively accurate.

Such as, if total measuring point is N number of, each measuring point respective frequencies f _iwith induced voltage amplitude V _ior magnetic field amplitude H _i.In log-log coordinate system, draw out induced voltage-frequency curve (example as electric field component curve), and ask for first slope k at each measuring point place by following formula three _i.

Formula three: $k_i=\frac{\lg V_{i+1}-\lg V_i}{\lg f_{i+1}-\lg f_i},i=\mathrm{1,2}...,N-1$

If the first mean value and first standard deviation of each measuring point first slope are respectively and s, then

Formula four: $\stackrel{\‾}{k}=\frac{k_1+k_2+...+k_{N-1}}{N-1}$

Formula five: $s=\sqrt{\frac{{(k_1-\stackrel{\‾}{k})}^2+{(k_2-\stackrel{\‾}{k})}^2+...+{(k_{N-1}-\stackrel{\‾}{k})}^2}{N-1}}$

For each measuring point, by the first slope of this measuring point and the difference of the first mean value $(k_i-\stackrel{\‾}{k},i=\mathrm{1,2},...,N-1)$ Compare with s, if $(k_i-\stackrel{\‾}{k})>s,$ Then think that this measuring point slope is overproof, and this measuring point is defined as first departs from measuring point.

Similarly, in log-log coordinate system, draw out magnetic field amplitude-frequency curve (example as magnetic-field component curve), and ask for second slope k at each measuring point place by following formula six ' _i:

Formula six: ${k^{,}}_i=\frac{\lg H_{i+1}-\lg H_i}{\lg f_{i+1}-\lg f_i},i=\mathrm{1,2}...,N-1$

If the second mean value and second standard deviation of each measuring point second slope are respectively and s ', then

Formula seven: ${\stackrel{\‾}{k}}^{,}=\frac{{k^{,}}_1+{k^{,}}_2...+k_{N-1}}{N-1}$

Formula eight: $s^{,}=\sqrt{\frac{{({k^{,}}_1-{\stackrel{\‾}{k}}^{,})}^2+{({k^{,}}_2-{\stackrel{\‾}{k}}^{,})}^2+...+{(k_{N-1}-\stackrel{\‾}{K})}^2}{N-1}}$

For each measuring point, by the second slope of this measuring point and the difference of the second mean value $({k^{,}}_i-{\stackrel{\‾}{k}}^{,},i=\mathrm{1,2},...,N-1)$ Compare with s ', if $({k^{,}}_i-{\stackrel{\‾}{k}}^{,})>s^{,},$ Then think that this measuring point slope is overproof, and this measuring point is defined as second departs from measuring point.

Preferably, in the step s 120, the CSAMT measurement result in region to be measured can comprise and utilizes the CSAMT horizontal electric field component in this region to be measured to carry out calculating and the apparent resistivity value obtained.

Such as, apparent resistivity value at each measuring point place can be calculated according to following formula nine:

Formula nine: ${\mathrm{\ρ}}^{E_x}=\frac{\mathrm{\π}{r}^3}{l_{\mathrm{AB}}\·l_{\mathrm{MN}}}\frac{\mathrm{\ΔV}}{I},$

Wherein, r is the distance between field source to measuring point, l _aBfor the distance between transmitting electrode, l _mNfor the distance between receiving electrode, Δ V is the voltage between potential electrode M, N, Δ V=E _xl _mN, E _xfor horizontal electric field component amplitude, and I is for sending electric current.

Embodiments of the invention additionally provide a kind of CSAMT measurement mechanism for electromagnetic interference (EMI) area, and as shown in Figure 3, this CSAMT measurement mechanism comprises: electromagnetic interference (EMI) area determining unit 1, and it is for determining whether region to be measured is electromagnetic interference (EMI) area; And measurement result obtains unit 2, it, for when region to be measured is electromagnetic interference (EMI) area, obtains the CSAMT measurement result in region to be measured according to the CSAMT horizontal electric field component in region to be measured.

Preferably, electromagnetic interference (EMI) area determining unit 1 can perform following process: the multiple measuring points determining region to be measured; At each measuring point of multiple measuring point, measure horizontal electric field component and horizontal component ofmagnetic field respectively; And according to the horizontal electric field component of multiple measuring point and horizontal component ofmagnetic field, determine horizontal electric field component error and the horizontal component ofmagnetic field error of multiple measuring point, and when horizontal electric field component error is less than horizontal component ofmagnetic field error, region to be measured is defined as electromagnetic interference (EMI) area.

Preferably, electromagnetic interference (EMI) area determining unit 1 can also perform following process: according to horizontal electric field component and the horizontal component ofmagnetic field of multiple measuring point, obtains horizontal electric field component curve and the horizontal component ofmagnetic field curve of multiple measuring point under log-log coordinate system; And when curve quality higher than horizontal component ofmagnetic field curve of the curve quality of horizontal electric field component curve, judge that horizontal electric field component error is less than horizontal component ofmagnetic field error.

Preferably, electromagnetic interference (EMI) area determining unit 1 can also perform following process: calculated level electric field component curve is in the first slope of each measuring point and the first mean value of each the first slope and the first standard deviation, and the measuring point difference of the first slope and the first mean value being greater than the first standard deviation is defined as first departs from measuring point; Calculated level magnetic-field component curve is in the second slope of each measuring point and the second mean value of each the second slope and the second standard deviation, and the measuring point difference of the second slope and the second mean value being greater than the second standard deviation is defined as second departs from measuring point; And when the first number departing from measuring point be less than second depart from the number of measuring point time, judge the curve quality of curve quality higher than horizontal component ofmagnetic field curve of horizontal electric field component curve.

Preferably, measurement result obtains unit 2 for the apparent resistivity value that will the CSAMT horizontal electric field component in region to be measured be utilized to carry out the calculating CSAMT measurement result as region to be measured.

Preferably, measurement result obtains unit 2 and obtains apparent resistivity value for calculating according to formula nine mentioned above, and wherein each parameter meaning is identical, no longer repeats here.

It should be noted that, electromagnetic interference (EMI) area determining unit 1 can perform the process in the step S110 of CSAMT measuring method as described above, and measurement result acquisition unit 2 can perform the process in the step S120 of CSAMT measuring method as described above, and similar function and effect can be reached, no longer describe in detail here.

Known by describing above, the above-mentioned CSAMT measuring method for electromagnetic interference (EMI) area according to the embodiment of the present invention or device, it is by utilizing horizontal electric field component to obtain CSAMT measurement result in electromagnetic interference (EMI) area, can obtain CSAMT measurement result relatively accurately for the area that electromagnetic interference (EMI) is serious.

Compared to prior art, the apparent resistivity precision calculated for CSAMT measuring method or the device in electromagnetic interference (EMI) area of the present invention only depends on the accuracy of electric field component, and do not affect by magnetic-field component, especially obviously serious area is disturbed for magnetic-field component and can obtains CSAMT measurement result comparatively accurately.On the other hand, the quantity of information of CSAMT horizontal electric field component, much larger than horizontal component ofmagnetic field, therefore, although CSAMT measuring method of the present invention or device do not adopt horizontal component ofmagnetic field information, also can obtain measurement result comparatively accurately.

Thus, when in electromagnetic interference (EMI) area by CSAMT measuring method of the present invention or application of installation in time inferring subsurface geologic structures and distribution, can obtain and infer more accurately and analysis result.

The application example of a kind of CSAMT measuring method for electromagnetic interference (EMI) area of the embodiment of the present invention is described below in conjunction with Fig. 4-6.

Adopt metering system shown in Figure 1B, survey district's (example as region to be measured) according to a kind of CSAMT measuring method for electromagnetic interference (EMI) area described by the embodiment of the present invention in Tangshan, Hebei Province and carry out CSAMT measurement, obtain horizontal electric field component curve as shown in Figure 4 and horizontal component ofmagnetic field curve as shown in Figure 5.

For Fig. 4, calculating measure-point amount that in horizontal electric field component curve, slope is overproof (i.e. the first number departing from measuring point) is 5; For Fig. 5, calculating measure-point amount that in horizontal component ofmagnetic field curve, slope is overproof (i.e. the second number departing from measuring point) is 12.Therefore, it is larger that horizontal component ofmagnetic field Hy is disturbed impact, and also can find out in figure that severe oscillations appears in field curve.

To observed horizontal electric field component data and horizontal component ofmagnetic field data, according to formula two computer card Buddhist nun Asian TV Station resistivity, result of calculation is as shown in the solid line in Fig. 6; The CSAMT measuring method utilizing the embodiment of the present invention to provide, only considers horizontal electric field component, calculates apparent resistivity according to formula nine, and result of calculation is as shown in the dotted line in Fig. 6.Wherein, in Fig. 6, horizontal direction represents frequency, and vertical direction represents apparent resistivity.

Two apparent resistivity curves in comparison diagram 6 are known: because magnetic interference is than stronger, and the apparent resistivity curve distortion calculated according to formula two is very serious; And only adopt horizontal component of electric field data, and calculate apparent resistivity value according to formula nine, result of calculation curve then smoother, apparent resistivity curve distortion level is less.Solid line in comparison diagram 5 and dotted line can be found out: in electromagnetic interference (EMI) comparatively great Ce district, if the horizontal component ofmagnetic field data observed are poor, then should abandon magnetic field data, only adopt electric field data to calculate formation apparent resistivity value.

Although disclosed embodiment as above, the embodiment that its content just adopts for the ease of understanding technical scheme of the present invention, is not intended to limit the present invention.Technician in any the technical field of the invention; under the prerequisite not departing from disclosed core technology scheme; any amendment and change can be made in the form implemented and details; but the protection domain that the present invention limits, the scope that still must limit with appending claims is as the criterion.

Claims (12)

1. for the CSAMT measuring method in electromagnetic interference (EMI) area, it is characterized in that, described CSAMT measuring method comprises:

Determine whether region to be measured is electromagnetic interference (EMI) area; And

When described region to be measured is electromagnetic interference (EMI) area, obtain the CSAMT measurement result in described region to be measured according to the CSAMT horizontal electric field component in described region to be measured.

2. CSAMT measuring method according to claim 1, is characterized in that, described CSAMT measurement result comprises and utilizes the CSAMT horizontal electric field component in described region to be measured to carry out the apparent resistivity value calculated.

3. CSAMT measuring method according to claim 2, is characterized in that, described apparent resistivity value obtains according to following formulae discovery:

${\mathrm{\ρ}}^{E_x}=\frac{\mathrm{\π}{r}^3}{l_{\mathrm{AB}}\·l_{\mathrm{MN}}}\frac{\mathrm{\ΔV}}{I},$

Wherein, r is the distance between field source to measuring point, l _aBfor the distance between transmitting electrode, l _mNfor the distance between receiving electrode, Δ V is the voltage between potential electrode M, N, Δ V=E _xl _mN, E _xfor horizontal electric field component amplitude, and I is for sending electric current.

4. the CSAMT measuring method according to any one of claim 1-3, is characterized in that, describedly determines that whether region to be measured is that the step in electromagnetic interference (EMI) area comprises:

Determine multiple measuring points in described region to be measured;

At each measuring point of described multiple measuring point, measure horizontal electric field component and horizontal component ofmagnetic field respectively; And

According to horizontal electric field component and the horizontal component ofmagnetic field of described multiple measuring point, determine horizontal electric field component error and the horizontal component ofmagnetic field error of described multiple measuring point, and when described horizontal electric field component error is less than described horizontal component ofmagnetic field error, described region to be measured is defined as electromagnetic interference (EMI) area.

5. CSAMT measuring method according to claim 4, is characterized in that, described CSAMT measuring method also comprises:

According to horizontal electric field component and the horizontal component ofmagnetic field of described multiple measuring point, obtain horizontal electric field component curve and the horizontal component ofmagnetic field curve of described multiple measuring point under log-log coordinate system; And

When curve quality higher than described horizontal component ofmagnetic field curve of the curve quality of described horizontal electric field component curve, judge that described horizontal electric field component error is less than described horizontal component ofmagnetic field error.

6. CSAMT measuring method according to claim 5, is characterized in that, described CSAMT measuring method also comprises:

Calculate described horizontal electric field component curve in the first slope of each measuring point and the first mean value of each the first slope and the first standard deviation, and the measuring point difference of the first slope and described first mean value being greater than described first standard deviation is defined as first departs from measuring point;

Calculate described horizontal component ofmagnetic field curve in the second slope of each measuring point and the second mean value of each the second slope and the second standard deviation, and the measuring point difference of the second slope and described second mean value being greater than described second standard deviation is defined as second departs from measuring point; And

When described first number departing from measuring point be less than described second depart from the number of measuring point time, judge the curve quality of the curve quality of described horizontal electric field component curve higher than described horizontal component ofmagnetic field curve.

7. for the CSAMT measurement mechanism in electromagnetic interference (EMI) area, it is characterized in that, described CSAMT measurement mechanism comprises:

Electromagnetic interference (EMI) area determining unit, it is for determining whether region to be measured is electromagnetic interference (EMI) area; And

Measurement result obtains unit, and it is for when described region to be measured is electromagnetic interference (EMI) area, obtains the CSAMT measurement result in described region to be measured according to the CSAMT horizontal electric field component in described region to be measured.

8. CSAMT measurement mechanism according to claim 7, it is characterized in that, described measurement result obtains apparent resistivity value that unit is used for utilizing the CSAMT horizontal electric field component in described region to be measured to carry out the calculating CSAMT measurement result as described region to be measured.

9. CSAMT measurement mechanism according to claim 8, is characterized in that, described measurement result obtains unit and is used for obtaining apparent resistivity value according to following formulae discovery:

${\mathrm{\ρ}}^{E_x}=\frac{\mathrm{\π}{r}^3}{l_{\mathrm{AB}}\·l_{\mathrm{MN}}}\frac{\mathrm{\ΔV}}{I},$

Wherein, r is the distance between field source to measuring point, l _aBfor the distance between transmitting electrode, l _mNfor the distance between receiving electrode, Δ V is the voltage between potential electrode M, N, Δ V=E _xl _mN, E _xfor horizontal electric field component amplitude, and I is for sending electric current.

10. the CSAMT measurement mechanism according to any one of claim 7-9, is characterized in that, described electromagnetic interference (EMI) area determining unit is used for:

Determine multiple measuring points in described region to be measured;

At each measuring point of described multiple measuring point, measure horizontal electric field component and horizontal component ofmagnetic field respectively; And

According to horizontal electric field component and the horizontal component ofmagnetic field of described multiple measuring point, determine horizontal electric field component error and the horizontal component ofmagnetic field error of described multiple measuring point, and when described horizontal electric field component error is less than described horizontal component ofmagnetic field error, described region to be measured is defined as electromagnetic interference (EMI) area.

11. CSAMT measurement mechanisms according to claim 10, is characterized in that, described electromagnetic interference (EMI) area determining unit is used for:

According to horizontal electric field component and the horizontal component ofmagnetic field of described multiple measuring point, obtain horizontal electric field component curve and the horizontal component ofmagnetic field curve of described multiple measuring point under log-log coordinate system; And

When curve quality higher than described horizontal component ofmagnetic field curve of the curve quality of described horizontal electric field component curve, judge that described horizontal electric field component error is less than described horizontal component ofmagnetic field error.

12. CSAMT measurement mechanisms according to claim 11, is characterized in that, described electromagnetic interference (EMI) area determining unit is used for:

Calculate described horizontal electric field component curve in the first slope of each measuring point and the first mean value of each the first slope and the first standard deviation, and the measuring point difference of the first slope and described first mean value being greater than described first standard deviation is defined as first departs from measuring point;

Calculate described horizontal component ofmagnetic field curve in the second slope of each measuring point and the second mean value of each the second slope and the second standard deviation, and the measuring point difference of the second slope and described second mean value being greater than described second standard deviation is defined as second departs from measuring point; And

When described first number departing from measuring point be less than described second depart from the number of measuring point time, judge the curve quality of the curve quality of described horizontal electric field component curve higher than described horizontal component ofmagnetic field curve.