Ground and underground combined water yield calculation method suitable for coal mine

Abstract

The invention relates to a ground and underground combined water yield calculation method suitable for a coal mine. The method comprises the following steps: acquiring a conductivity value by using a ground direct current method; acquiring electromagnetic wave field intensity by using an underground wireless electromagnetic wave perspective method; calculating an attenuation coefficient according to the electromagnetic wave field intensity; calculating a coal seam dielectric constant according to the apparent resistivity and the attenuation coefficient; and determining the coal seam internal water abundance according to the coal seam dielectric constant. According to the method, a ground direct current method and an underground wireless electromagnetic wave perspective method are combined, the ground direct current method aims at obtaining apparent conductivity, and the wireless electromagnetic wave perspective method aims at obtaining attenuation coefficients; the dielectric constant of the coal seam can be obtained according to the apparent conductivity obtained through the ground direct current method and the attenuation coefficient obtained through the wireless electromagnetic wave perspective method, then the water yield property in the coal seam is determined, and therefore the water yield property calculation accuracy can be improved through combination of the two methods.

Description

Technical Field

[0001] The invention relates to the field of coal detection, and in particular to a ground-underground combined water-richness calculation method applicable to coal mines. Background Art

[0002] In the existing technology, the common methods for detecting the water-richness inside the underground working face of coal mines include slot wave seismic, audio frequency electro-perspective, radio wave perspective, transient electromagnetic method, etc., and usually one or several technical methods are used for detection. However, these methods are all underground detection, which is affected by the interference of the mine environment, cannot suppress false anomalies, and the results have multiple solutions, resulting in low accuracy of detection results. Summary of the invention

[0003] In order to overcome the existing technology, the common methods for detecting the water-richness inside the underground working face of coal mines are slot wave seismic, audio frequency electro-perspective, radio wave perspective, transient electromagnetic method, etc., and one or several technical methods are usually used for detection. However, these methods are all underground detection, which are affected by the interference of the mine environment, cannot suppress false anomalies, and the results have multiple solutions, resulting in low accuracy of the detection results. The present invention provides a ground and underground combined water-richness calculation method suitable for coal mines, which can effectively improve the detection accuracy of coal seam water-richness.

[0004] The technical solution of the present invention is: a ground and underground combined water richness calculation method applicable to coal mines, comprising the following steps:

[0005] The conductivity value is obtained by using the ground direct current method;

[0006] Use underground radio electromagnetic wave perspective method to obtain electromagnetic wave field strength;

[0007] Calculating the attenuation coefficient according to the electromagnetic wave field intensity;

[0008] The dielectric constant of the coal seam is calculated according to the apparent resistivity and the attenuation coefficient;

[0009] The water richness inside the coal seam is determined based on the dielectric constant of the coal seam.

[0010] Through ground direct current exploration, the voltage V and current I values ​​of each measuring point are measured; then the apparent resistivity conversion is performed: the normalized voltage V / I of different pole distances at each measuring point is used to calculate the apparent resistivity using the formula:

[0011] ρ s =K×V / I

[0012] Where K is the device coefficient related to the electrode distance;

[0013] The apparent resistivity of strata at different depths is obtained through inversion; the apparent conductivity value near the coal seam at the measuring point is obtained by taking the resistivity value at the coal seam depth and performing inverse calculation.

[0014] The electromagnetic wave field strength is obtained by underground radio electromagnetic wave perspective method, and the attenuation coefficient is calculated using the electromagnetic wave formula, wherein the electromagnetic wave formula is:

[0015]

[0016] Among them, α is the attenuation coefficient, H is the electromagnetic wave field strength, H0 is the initial radiation field strength, r is the distance between the magnetic field emission point and the magnetic field receiving point, and ψ is the angle between the antenna axis of the magnetic field emission point and the direction of the test point in the electromagnetic wave.

[0017] The dielectric constant of the coal seam is calculated according to the dielectric constant formula of the coal seam, wherein the dielectric constant formula of the coal seam is:

[0018]

[0019] Among them, ε is the dielectric constant of the coal seam, μ is the vacuum magnetic permeability, ω is the angular frequency, σ is the apparent conductivity, and α is the attenuation coefficient; σ is the apparent conductivity obtained after direct current depth sounding at the ground position corresponding to the underground detection position.

[0020] Beneficial effect: The present invention is a combination of two algorithms, namely, the surface direct current method and the underground radio electromagnetic wave perspective method. The purpose of the surface direct current method is to obtain the apparent conductivity, and the purpose of the radio electromagnetic wave perspective method is to obtain the attenuation coefficient. The dielectric constant of the coal seam can be obtained according to the apparent conductivity obtained by the surface direct current method and the attenuation coefficient obtained by the radio electromagnetic wave perspective method, and then the water richness inside the coal seam can be determined. Therefore, the combination of these two methods can improve the accuracy of the water richness calculation. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of the process of the present invention;

[0022] Figure 2 It is a schematic diagram of the construction method of the electromagnetic wave perspective method in the present invention;

[0023] Figure 3 This is a comparison chart of the dielectric constants of common underground media and coal seams in the present invention. DETAILED DESCRIPTION

[0024] The present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments, but the protection scope and application scope of the present invention are not limited.

[0025] A method for calculating the combined water richness of ground and underground coal mines, such as Figure 1As shown, the method includes the following steps: obtaining the conductivity value by using the ground direct current method; obtaining the electromagnetic wave field strength by using the underground radio electromagnetic wave perspective method; calculating the attenuation coefficient according to the electromagnetic wave field strength; calculating the dielectric constant of the coal seam according to the apparent resistivity and the attenuation coefficient; and determining the water richness inside the coal seam according to the dielectric constant of the coal seam.

[0026] like Figure 2 As shown, the radio electromagnetic wave perspective method uses the fixed-voltage method for observation, and the transmitting points and receiving points are arranged in the tunnels on both sides of the working face.

[0027] A DC depth sounding point is arranged at the ground position corresponding to each receiving point, and the DC depth sounding inversion depth is required to be greater than the coal seam burial depth. The data is measured, and the electromagnetic wave field strength of each receiving point is measured by the radio electromagnetic wave perspective method; the voltage and current data of each measuring point are measured by the ground DC depth sounding method. Then the data is processed, and the radio electromagnetic wave perspective method uses the electromagnetic wave formula to calculate the attenuation coefficient, where the electromagnetic wave formula is:

[0028]

[0029] Among them, α is the attenuation coefficient, H is the electromagnetic wave field strength, H0 is the initial radiation field strength, r is the distance between the magnetic field emission point and the magnetic field receiving point, and ψ is the angle between the antenna axis of the magnetic field emission point and the direction of the test point in the electromagnetic wave.

[0030] In ground direct current electrical exploration, the voltage V and current I values ​​of each measuring point are measured. Then the apparent resistivity conversion is performed: the normalized voltage V / I of each measuring point with different pole distances is used to calculate the apparent resistivity using the formula:

[0031] ρ s =K×V / I

[0032] Where K is the device coefficient related to the electrode distance.

[0033] The apparent resistivity of strata at different depths is obtained through inversion. The apparent conductivity value near the coal seam at the measuring point is obtained by reciprocal calculation of the resistivity value at the coal seam depth.

[0034] The dielectric constant of the coal seam is calculated according to the dielectric constant formula of the coal seam, wherein the dielectric constant formula of the coal seam is:

[0035]

[0036] Among them, ε is the dielectric constant of the coal seam, μ is the vacuum magnetic permeability, ω is the angular frequency, σ is the apparent conductivity, and α is the attenuation coefficient. σ is the apparent conductivity obtained after the DC depth sounding at the ground position corresponding to the underground detection position.

[0037] like Figure 3As shown, the water richness inside the coal seam is determined by the dielectric constant of the coal seam. The larger the dielectric constant, the stronger the water richness.

[0038] The present invention is a combination of two algorithms, namely, a surface direct current method and an underground radio electromagnetic wave perspective method. The purpose of the surface direct current method is to obtain apparent conductivity, and the purpose of the radio electromagnetic wave perspective method is to obtain an attenuation coefficient. The dielectric constant of the coal seam can be obtained based on the apparent conductivity obtained by the surface direct current method and the attenuation coefficient obtained by the radio electromagnetic wave perspective method, and then the water richness inside the coal seam can be determined. Therefore, the combination of these two methods can improve the accuracy of water richness calculation.

[0039] The above description of the disclosed embodiments enables those skilled in the art to implement and use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit and scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest range consistent with the principles and novel features disclosed herein.

Claims

1. A method for calculating the combined water richness of ground and underground coal mines, characterized in that: The following steps are involved: The conductivity value is obtained by using the ground direct current method; Use underground radio electromagnetic wave perspective method to obtain electromagnetic wave field strength; Calculating the attenuation coefficient according to the electromagnetic wave field intensity; The dielectric constant of the coal seam is calculated according to the apparent resistivity and the attenuation coefficient; The water richness inside the coal seam is determined based on the dielectric constant of the coal seam.

2. A method for calculating the combined water richness of ground and underground coal mines according to claim 1, characterized in that: Through ground direct current exploration, the voltage V and current I values ​​of each measuring point are measured; then the apparent resistivity conversion is performed: the normalized voltage V / I of different pole distances at each measuring point is used to calculate the apparent resistivity using the formula: r s =K×V / I Where K is the device coefficient related to the electrode distance; The apparent resistivity of strata at different depths is obtained through inversion; the apparent conductivity value near the coal seam at the measuring point is obtained by taking the resistivity value at the coal seam depth and performing inverse calculation.

3. A method for calculating the combined water richness of ground and underground coal mines according to claim 2, characterized in that: The electromagnetic wave field strength is obtained by underground radio electromagnetic wave perspective method, and the attenuation coefficient is calculated using the electromagnetic wave formula, wherein the electromagnetic wave formula is: Among them, α is the attenuation coefficient, H is the electromagnetic wave field strength, H0 is the initial radiation field strength, r is the distance between the magnetic field emission point and the magnetic field receiving point, and ψ is the angle between the antenna axis of the magnetic field emission point and the direction of the test point in the electromagnetic wave.

4. A method for calculating the combined water richness of ground and underground coal mines as claimed in claim 3, characterized in that: The dielectric constant of the coal seam is calculated according to the dielectric constant formula of the coal seam, wherein the dielectric constant formula of the coal seam is: Among them, ε is the dielectric constant of the coal seam, μ is the vacuum magnetic permeability, ω is the angular frequency, σ is the apparent conductivity, and α is the attenuation coefficient; σ is the apparent conductivity obtained after direct current depth sounding at the ground position corresponding to the underground detection position.

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