Three-dimensional space positioning method for transient electromagnetic exploration of abnormal water body by multi-drilling combination

Abstract

This application relates to a three-dimensional spatial positioning method for anomaly water bodies using multi-bore combined transient electromagnetic exploration. To improve the accuracy of the detection results, multiple boreholes are used for joint exploration. After obtaining the observation data, the background signal is first extracted to obtain the pure anomaly signal generated by the water-bearing anomaly. By finding the extreme values ​​at the same depth on multiple boreholes, the center position of the water-bearing anomaly is determined by using the borehole Z component signal combined with the three-dimensional spatial positioning method. Similar processing is performed on the anomaly signals at other depths and other measurement times to finally obtain the spatial distribution result of the anomaly body. Since the use of X and Y components with relatively small signal strength is avoided, the obtained results are more accurate and reliable.

Description

Technical Field

[0001] This application relates to the field of geophysical exploration technology, specifically to a three-dimensional spatial positioning method for anomaly water bodies using multi-hole combined transient electromagnetic exploration. Background Technology

[0002] Coal mine water hazards are the second largest risk source after gas accidents. The causes of water hazards are multifaceted, one important factor being the insufficient accuracy of detecting hidden water bodies. The harsh mining environment and confined working space in coal mines make it difficult to implement many efficient surface exploration methods underground. This results in a significant difference in the density and accuracy of underground exploration work compared to surface exploration, severely hindering the achievement of the current goals of rapid, efficient, and intelligent mining.

[0003] There are many types of boreholes in coal mines. Boreholes can greatly increase the scope of various detection operations. At present, there are increasing cases of using boreholes for borehole imaging and seismic advance detection. In terms of water hazard detection, technologies such as using boreholes for monitoring water inrush in the resistivity of the bottom plate and conducting transient electromagnetic side water body detection in boreholes are also under continuous development.

[0004] By conducting transient electromagnetic detection in boreholes, it is possible to detect hidden hazardous water bodies within a certain range beside the borehole. Figure 1 A schematic diagram of borehole transient electromagnetic technology for probing water-bearing bodies is shown. Electromagnetic wave transmitting / receiving equipment moves within the borehole to probe the surrounding water-bearing body, and the spatial location of the water-bearing body is determined by analyzing the received data. However, this method has significant drawbacks.

[0005] If only the Z component data is used from the X, Y, and Z components of the signal received in the borehole, it is impossible to determine the specific location of anomalies such as water-bearing bodies beside the borehole. Only the distance of the anomaly relative to the borehole can be determined. With a fixed distance, the anomaly can rotate freely within a 360-degree range around the borehole axis. Figure 2 A schematic diagram of the equivalent effect within a 360-degree radial range of the borehole in the abnormal water body is shown. Figure 2 At the 16 locations marked in the diagram, anomalies of the same size (size and shape) and resistivity are completely symmetrical with respect to the borehole location, and the resulting anomaly signals have completely identical Z components. Using only the Z component to determine the location of the anomaly has obvious theoretical flaws.

[0006] Figure 3The diagram shows a comparison of the X, Y, and Z components of the pure anomalous signal of an anomalous body of the same size at different locations. When the anomalous body changes from position 1 to position 5, the three component signals generated by the anomalous body are completely consistent in the vertical Z component. The X and Y components change drastically. At position 1, the Y component signal is basically 0, and at position 5, the X component is basically 0. The amplitudes of the X and Y components vary within the range of 0 to half the amplitude of the Z component. At certain moments, the difference between the vertical component and the horizontal component can reach more than 10 times.

[0007] If the horizontal component is used, the data acquisition sensor needs to have extremely high acquisition accuracy and an extremely clean measurement environment. This measurement environment includes the environment of the construction site and the circuit environment of the instrument itself, and the measurement process must be absolutely stable. This is because the amplitude of the horizontal X-direction and Y-direction signals is extremely small, making them very easy to be submerged in various kinds of noise, which makes the measurement extremely difficult. It is difficult for a single set of equipment to simultaneously achieve high accuracy, high resolution, and wide range. To achieve a wide range and ensure that the Z component can be measured very accurately, some measurement accuracy must be sacrificed. In some directions, the amplitude of the X-component or Y-component signals is small, and low accuracy will lead to signal distortion. If a high-precision measurement scheme is adopted, at certain times, the value of the Z component may exceed the instrument's own range. A single set of equipment cannot simultaneously meet the requirements of range and accuracy.

[0008] The electromagnetic environment in underground coal mines is extremely complex, with numerous ventilation, electrical control, and power transmission devices whose power far exceeds that of transient electromagnetic borehole detection equipment. The electromagnetic radiation range covers the entire mine, making high-precision and high-sensitivity signal detection extremely difficult, and accurate measurement of the horizontal component very challenging. Therefore, traditional three-component measurement methods are not very accurate in three-dimensional spatial positioning of concealed water-bearing bodies, and the results are unreliable. Summary of the Invention

[0009] To overcome at least one deficiency in the prior art, this application provides a three-dimensional spatial positioning method for anomaly water bodies using multi-hole combined transient electromagnetic exploration.

[0010] Firstly, a method for three-dimensional spatial localization of anomalous water bodies using multi-hole combined transient electromagnetic detection is provided, including:

[0011] Acquire transient electromagnetic signal data of each measuring point in each borehole arranged in the target area at multiple sampling times; there are multiple boreholes arranged in the target area that are parallel to each other in space, and the number of boreholes is not less than 3; multiple measuring points are set in each borehole, and the measuring points with the same number in the multiple boreholes have the same depth;

[0012] Based on the transient electromagnetic signal data of each measuring point in each borehole at multiple sampling times, the original multi-track diagram corresponding to each borehole is obtained; the original multi-track diagram includes multiple curves, each curve is composed of transient electromagnetic signal data of all measuring points at a certain sampling time;

[0013] Based on the relationship between the apparent resistivity of the formation background and the background signal at each sampling time for each borehole, the background signal at each sampling time for each borehole is determined.

[0014] Remove the background signal at each sampling time from the original multi-track map corresponding to each borehole to obtain the pure anomaly multi-track map corresponding to each borehole; the pure anomaly multi-track map includes multiple curves, each curve is composed of the abnormal data of all measurement points at a certain sampling time.

[0015] Based on the pure anomaly multi-track map corresponding to each borehole, the anomaly data of the measuring points with the same number in all boreholes at each sampling time are extracted to form an outlier sequence A. ki ={abv 1ki ,abv 2ki ,…abv jki …abv qki}, where A ki For the measurement point numbered k at sampling time t i The corresponding outlier sequence, abv jki For the measuring point numbered k in the j-th borehole at sampling time t i Abnormal data, where q is the number of boreholes;

[0016] Based on the anomaly sequence corresponding to each sampling time for measuring points with the same number, an equation is constructed relating the location of the abnormal water body to the anomaly sequence.

[0017] Solving the equations yields the location of the anomalous water bodies at each sampling time for measuring points with the same number, i.e., the spatial distribution of the anomalous water bodies.

[0018] In one embodiment, the background signal for each sampling time corresponding to each borehole is determined based on the relationship between the apparent resistivity of the formation background and the background signal at each sampling time for each borehole, including:

[0019] Calculate sampling time t i Apparent resistivity of the underlying strata

[0020]

[0021] Where M is the number of measuring points in the borehole, j is the measuring point number, and ρs(i,j) is the sampling time t. i The resistivity value reflected by the signal data collected at the j-th measuring point;

[0022] Calculate sampling time t i Background signal S below i :

[0023]

[0024] Where μ0 is the vacuum permeability and P is the emission magnetic moment.

[0025] In one embodiment, based on the pure anomaly multi-track map corresponding to each borehole, the anomaly data of all boreholes with the same number at each sampling time are extracted to form an outlier sequence, including:

[0026] Step S51: Based on the pure anomaly multi-track map corresponding to each borehole, determine at least one maximum point of all curves in each borehole, and the measurement point corresponding to the maximum point; the number of maximum points is the same as the number of abnormal water bodies.

[0027] Step S52: For each borehole, the measuring points corresponding to the maximum value points are sorted in ascending order according to the depth corresponding to the measuring points to obtain the maximum value measuring point sequence for each borehole.

[0028] Step S53: Select the first measurement point in the maximum value measurement point sequence as the current measurement point, and determine the sampling time when the abnormal data of the current measurement point is the largest, denoted as the appropriate sampling time t. top And extract all boreholes at the current measuring point at the appropriate sampling time t. top The corresponding abnormal data form an outlier sequence;

[0029] Step S54, return to step S53, select the next measuring point in the maximum value measuring point sequence as the current measuring point; finally obtain the outlier value sequence of each measuring point in the maximum value measuring point sequence at the appropriate sampling time; each outlier value sequence is used to construct the equation between the center position of each anomalous water body and each outlier value sequence; the equation is used to obtain the center position of each anomalous water body;

[0030] Step S55: Extract the abnormal data corresponding to each measuring point of the maximum value measuring point sequence in all boreholes at each remaining sampling time, and construct the abnormal value sequence of each measuring point of the maximum value measuring point sequence at each remaining sampling time;

[0031] Step S56: Extract the abnormal data corresponding to each measuring point in all boreholes except for the measuring points in the maximum value measuring point sequence at each sampling time, and form the abnormal value sequence of each other measuring point at each sampling time.

[0032] In one embodiment, the equation relating the location of the anomalous water body to the sequence of outliers is:

[0033]

[0034] Where (x1,y1), (x2,y2), (x3,y3)…(x(q-1),y(q-1))…(xq,yq) are the coordinates of each borehole axis in the XOY plane, q is the number of boreholes, (x0,y0) is the location of the abnormal water body, and abv 1ki ,abv 2ki ,abv 3ki …abv (q-1)ki ,abv qki These are the sampling times of the measuring point k in each borehole at sampling time t. i The corresponding abnormal data.

[0035] Secondly, a three-dimensional spatial positioning device for detecting abnormal water bodies using multi-hole combined transient electromagnetic detection is provided, comprising:

[0036] The transient electromagnetic signal acquisition module is used to acquire transient electromagnetic signal data of each measuring point in each borehole arranged in the target area at multiple sampling times; there are multiple boreholes arranged in parallel to each other in space in the target area, and the number of boreholes is not less than 3; multiple measuring points are set in each borehole, and the measuring points with the same number in the multiple boreholes have the same depth;

[0037] The original multi-track plot acquisition module is used to obtain the original multi-track plot corresponding to each borehole based on the transient electromagnetic signal data of each measuring point in each borehole at multiple sampling times. The original multi-track plot includes multiple curves, and each curve is composed of transient electromagnetic signal data of all measuring points at a certain sampling time.

[0038] The background signal determination module is used to determine the background signal for each borehole at each sampling time based on the relationship between the apparent resistivity of the formation background and the background signal at each sampling time for each borehole.

[0039] The pure anomaly multi-track map acquisition module is used to remove the background signal at each sampling time corresponding to each borehole from the original multi-track map corresponding to each borehole to obtain the pure anomaly multi-track map corresponding to each borehole. The pure anomaly multi-track map includes multiple curves, and each curve is composed of the abnormal data of all measurement points at a certain sampling time.

[0040] The outlier sequence construction module is used to extract outlier data from all boreholes with the same measurement point at each sampling time, based on the pure outlier multi-track map corresponding to each borehole, to form an outlier sequence A. ki ={abv 1kq ,abv 2kq ,…abv jkq …abv qki}, where A kq For the measurement point numbered k at sampling time t i The corresponding outlier sequence, abvjki For the measuring point numbered k in the j-th borehole at sampling time t i Abnormal data, where q is the number of boreholes;

[0041] The equation construction module is used to construct equations for the location of abnormal water bodies and the sequence of abnormal values ​​based on the sequence of abnormal values ​​corresponding to each sampling time of measuring points with the same number.

[0042] The solver module is used to solve the equations and obtain the location of the abnormal water bodies at each sampling time for measuring points with the same number, i.e., the spatial distribution of the abnormal water bodies.

[0043] In one embodiment, the background signal determination module is further configured to:

[0044] Calculate sampling time t i Apparent resistivity of the underlying strata

[0045]

[0046] Where M is the number of measuring points in the borehole, j is the measuring point number, and ρs(i,j) is the sampling time t. i The resistivity value reflected by the signal data collected at the j-th measuring point;

[0047] Calculate sampling time t i Background signal S below i :

[0048]

[0049] Where μ0 is the vacuum permeability and P is the emission magnetic moment.

[0050] In one embodiment, the outlier sequence construction module is also used for:

[0051] Step S51: Based on the pure anomaly multi-track map corresponding to each borehole, determine at least one maximum point of all curves in each borehole, and the measurement point corresponding to the maximum point; the number of maximum points is the same as the number of abnormal water bodies.

[0052] Step S52: For each borehole, the measuring points corresponding to the maximum value points are sorted in ascending order according to the depth corresponding to the measuring points to obtain the maximum value measuring point sequence for each borehole.

[0053] Step S53: Select the first measurement point in the maximum value measurement point sequence as the current measurement point, and determine the sampling time when the abnormal data of the current measurement point is the largest, denoted as the appropriate sampling time t. top And extract all boreholes at the current measuring point at the appropriate sampling time t. top The corresponding abnormal data form an outlier sequence;

[0054] Step S54, return to step S53, select the next measuring point in the maximum value measuring point sequence as the current measuring point; finally obtain the outlier value sequence of each measuring point in the maximum value measuring point sequence at the appropriate sampling time; each outlier value sequence is used to construct the equation between the center position of each anomalous water body and each outlier value sequence; the equation is used to obtain the center position of each anomalous water body;

[0055] Step S55: Extract the abnormal data corresponding to each measuring point of the maximum value measuring point sequence in all boreholes at each remaining sampling time, and construct the abnormal value sequence of each measuring point of the maximum value measuring point sequence at each remaining sampling time;

[0056] Step S56: Extract the abnormal data corresponding to each measuring point in all boreholes except for the measuring points in the maximum value measuring point sequence at each sampling time, and form the abnormal value sequence of each other measuring point at each sampling time.

[0057] In one embodiment, the equation relating the location of the anomalous water body to the sequence of outliers is:

[0058]

[0059] Where (x1,y1), (x2,y2), (x3,y3)…(x(q-1),y(q-1))…(xq,yq) are the coordinates of each borehole axis in the XOY plane, q is the number of boreholes, (x0,y0) is the location of the abnormal water body, and abv 1ki ,abv 2ki ,abv 3ki …abv (q-1)ki ,abv qki These are the sampling times of the measuring point k in each borehole at sampling time t. i The corresponding abnormal data.

[0060] Thirdly, a computer-readable storage medium is provided, which stores a computer program. When the computer program is executed by a processor, it implements the above-mentioned method for three-dimensional spatial positioning of abnormal water bodies by multi-hole combined transient electromagnetic exploration.

[0061] Fourthly, a computer program product is provided, including a computer program / instruction, which, when executed by a processor, implements the aforementioned method for three-dimensional spatial positioning of anomalous water bodies using multi-hole combined transient electromagnetic exploration.

[0062] Compared with the prior art, this application has the following advantages: In order to improve the accuracy of the detection results, this application uses multiple boreholes for joint exploration. After obtaining the observation data, the background signal is first extracted to obtain the pure anomalous signal generated by the water-bearing anomaly. By finding the extreme values ​​at the same depth on multiple boreholes, the center position of the water-bearing anomaly is determined by using the borehole Z component signal combined with the three-dimensional spatial positioning method. Similar processing is carried out on the anomalous signals at other depths and other measurement times to finally obtain the spatial distribution result of the anomaly. Since the use of X and Y components with relatively small signal strength is avoided, the obtained results are more accurate and reliable. Attached Figure Description

[0063] This application can be better understood by referring to the description given below in conjunction with the accompanying drawings, which, together with the detailed description below, are incorporated in and form part of this specification. In the drawings:

[0064] Figure 1 A schematic diagram of borehole transient electromagnetic technology for exploring water-bearing bodies is shown;

[0065] Figure 2 An equivalent schematic diagram of the borehole in the abnormal water body within a radial range of 360 degrees is shown;

[0066] Figure 3 The following diagrams show the comparison of the X, Y, and Z components of the pure anomalous signal from an anomalous body of equal size at different locations: (a) is the comparison of the three components of the anomalous signal generated at location 1, (b) is the comparison of the three components of the anomalous signal generated at location 2, (c) is the comparison of the three components of the anomalous signal generated at location 3, (d) is the comparison of the three components of the anomalous signal generated at location 4, and (e) is the comparison of the three components of the anomalous signal generated at location 5.

[0067] Figure 4 A flowchart of a method for three-dimensional spatial localization of abnormal water bodies using multi-hole combined transient electromagnetic probing according to an embodiment of this application is shown.

[0068] Figure 5 The original multi-track plots for each borehole are shown;

[0069] Figure 6 A pure anomaly multi-channel plot is shown;

[0070] Figure 7 A schematic diagram of the equivalent magnetic dipole of the spatial anomaly signal source is shown;

[0071] Figure 8 A rectangular coordinate system parallel to the borehole orientation is shown;

[0072] Figure 9 A planar relationship diagram of the equivalent magnetic dipole and the borehole is shown;

[0073] Figure 10 This shows a rough spatial distribution map of the abnormal water bodies;

[0074] Figure 11 The inversion results of the three components of a single aperture are shown in the comparison diagram with the model;

[0075] Figure 12 A comparison diagram showing the joint inversion results of Z-component porous data with the model location is presented;

[0076] Figure 13 A schematic diagram of the multi-pore connection detection distance is shown;

[0077] Figure 14 A structural block diagram of a three-dimensional spatial positioning device for detecting abnormal water bodies using multi-hole combined transient electromagnetic detection according to an embodiment of this application is shown. Detailed Implementation

[0078] Exemplary embodiments of the present application will be described below with reference to the accompanying drawings. For clarity and brevity, not all features of the actual embodiments are described in the specification. However, it should be understood that many embodiment-specific decisions can be made in the development of any such actual embodiment to achieve the developer’s specific objectives, and these decisions may vary as the embodiments differ.

[0079] It should also be noted that, in order to avoid obscuring this application with unnecessary details, only the device structure closely related to the solution according to this application is shown in the accompanying drawings, while other details that are not closely related to this application are omitted.

[0080] It should be understood that this application is not limited to the described embodiments by virtue of the following description with reference to the accompanying drawings. In this document, embodiments may be combined with each other, features may be substituted or borrowed between different embodiments, and one or more features may be omitted in one embodiment, where feasible.

[0081] This application provides a method for three-dimensional spatial positioning of concealed water bodies within a certain range beside boreholes using only vertical Z-component data and multiple boreholes in combination. This solves the problem that current single-hole transient electromagnetic exploration cannot accurately locate the three-dimensional spatial position of water-bearing bodies. Based on in-hole transient electromagnetic technology, this application involves conducting in-hole transient electromagnetic exploration in three or more pre-deployed boreholes, measuring only the relatively reliable vertical Z-component signal, utilizing the correlation between signals at different measurement points within the borehole to remove background signals and retain only pure anomalous signals. Then, based on the amplitude of the anomalous signal at the same location in different boreholes, the three-dimensional spatial positioning of the water-bearing body beside the borehole is achieved.

[0082] This application provides a method for three-dimensional spatial localization of abnormal water bodies using transient electromagnetic detection with multiple boreholes. Figure 4 A flowchart illustrating a multi-hole combined transient electromagnetic probing method for three-dimensional spatial localization of anomalous water bodies according to an embodiment of this application is shown. See also... Figure 4 The methods include:

[0083] Step S1: Obtain transient electromagnetic signal data of each measuring point in each borehole arranged in the target area at multiple sampling times; there are multiple boreholes arranged in parallel to each other in space in the target area, and the number of boreholes is not less than 3; multiple measuring points are set in each borehole, and the measuring points with the same number in the multiple boreholes have the same depth.

[0084] Here, multiple parallel boreholes are arranged at certain intervals within the target area to be explored. These boreholes spatially surround the area to be explored to a certain extent, which is the location of at least one anomalous water body. Multiple measuring points are set in each borehole, with measuring points of the same number in multiple boreholes having the same depth for easy comparison of data from different boreholes. Electromagnetic transceivers are installed in the boreholes to acquire transient electromagnetic signal data from each measuring point at multiple sampling times.

[0085] The three-dimensional spatial positioning of the water-bearing body is based on the abnormal signal extracted from a single borehole and the equivalent magnetic moment of the water-bearing anomaly. In actual implementation, at least three or more boreholes are required to complete the positioning.

[0086] Step S2: Based on the transient electromagnetic signal data of each measuring point in each borehole at multiple sampling times, obtain the original multi-track diagram corresponding to each borehole; the original multi-track diagram includes multiple curves, each curve is composed of transient electromagnetic signal data of all measuring points at a certain sampling time; Figure 5 The original multitrack plots for each borehole are shown.

[0087] Step S3: Determine the background signal for each sampling time corresponding to each borehole based on the relationship between the apparent resistivity of the formation background and the background signal at each sampling time for each borehole.

[0088] Step S4: Remove the background signal at each sampling time from the original multi-track map corresponding to each borehole to obtain the pure anomaly multi-track map corresponding to each borehole; the pure anomaly multi-track map includes multiple curves, each curve is composed of the abnormal data of all measurement points at a certain sampling time; Figure 6 A pure anomaly multi-channel plot is shown.

[0089] Here, the extraction of background signals is the basis of this embodiment. The signals measured by the equipment / instrument include two parts: the background signal generated by the rock strata at the location of the borehole as a whole and the abnormal signal generated by the independent aquifer. The background signal is basically consistent at the same sampling time at different measurement points, while the abnormal signal is different at the same sampling time at different measurement points. The abnormal signal will gradually increase as the measurement point gets closer to the abnormal aquifer, and then gradually decrease until it disappears as the measurement point moves away. That is, the background signal exists throughout the entire measurement line, while the abnormal signal can only be received at a limited number of measurement points on the measurement line.

[0090] Background extraction is based on the correlation of signals from adjacent measurement points; that is, the signals measured at two adjacent points are relatively similar. The actual measurement process uses... Figure 1 The model is simplified by arranging multiple measuring points at equal intervals within the borehole, with each measuring point measuring a time-varying signal sequence. Each measuring point collects data at 40-100 time points, and the time points for data collection are identical across different measuring points; a single time point is referred to as a time channel in the professional field. Using the measuring point number / coordinates as the horizontal axis, the data at the same sampling time point at different measuring points are connected by curves. The curves from multiple time points are superimposed on a single graph, forming what is known as a multi-channel graph, such as... Figure 5 As shown.

[0091] For normal coal-bearing strata, the geological environment for coal formation is generally stable with little strata variation. When measuring at different points in the borehole, the signals from adjacent points show significant correlation. This is reflected in multi-track maps, where the line connecting the signal values ​​at the same time from different measuring points should approximate a horizontal straight line. When a water-bearing anomaly is present in the detection environment, the signal excited by the anomaly is superimposed on the approximate horizontal line, forming a 'bulge'. Finding a relatively reasonable horizontal baseline, the value of which can be considered the background value at that measurement time, yields the pure anomaly value. Subtracting this background value from the measured data gives the pure anomaly value. Figure 6 As shown.

[0092] Step S5: Based on the pure anomaly multi-track map corresponding to each borehole, extract the anomaly data of the measuring points with the same number in all boreholes at each sampling time to form an outlier sequence A. ki ={abv 1ki ,abv 2ki ,…abv jki …abv qki}, where A ki For the measurement point numbered k at sampling time t i The corresponding outlier sequence, abv jki For the measuring point numbered k in the j-th borehole at sampling time t i Abnormal data, where q is the number of boreholes;

[0093] Step S6: Based on the outlier sequence corresponding to each sampling time for measuring points with the same number, construct the equation for the location of the abnormal water body and the outlier sequence.

[0094] Step S7: Solve the equation to obtain the location of the abnormal water body at each sampling time for the measuring points with the same number, i.e., the spatial distribution of the abnormal water body.

[0095] In this embodiment, background signal extraction is used to eliminate the influence of the measurement environment and retain only the abnormal signal generated by the water-bearing anomaly, thus solving the problem of measurement environment interference. The equivalent evaluation of the abnormal signal is adopted to simplify the signal generated by the abnormal water-bearing body using analytical expression, avoiding the problem that the complex process of electromagnetic field propagation cannot be simply quantified and described, thus solving the problem of the quantitative relationship between the amplitude and distance of the abnormal signal. The Z-component combination of multiple boreholes is adopted to solve the three-dimensional spatial positioning problem that cannot be solved by a single component of a single borehole.

[0096] In one embodiment, step S3, determining the background signal for each sampling time corresponding to each borehole based on the relationship between the apparent resistivity of the formation background and the background signal at each sampling time for each borehole, includes:

[0097] Calculate sampling time t i Apparent resistivity of the underlying strata

[0098]

[0099] Where M is the number of measuring points in the borehole, j is the measuring point number, and ρs(i,j) is the sampling time t. i The resistivity value reflected by the signal data collected at the j-th measuring point;

[0100] Here, adjacent measuring points are correlated. At the same time, different measuring points should reflect similar electrical properties. That is, under normal background, the apparent resistivity values ​​of different measuring points at the same time should be similar. The average resistivity reflected by all measuring points at a certain time can be used to represent the influence of normal background.

[0101] In borehole transient electromagnetic exploration, apparent resistivity is used to reflect the electrical characteristics of the formation. The relationship between apparent resistivity and the measurement signal is as follows:

[0102]

[0103] in, Sampling time t i The rate of change of the borehole axial (Z direction) magnetic field strength at the j-th measuring point with respect to time can be obtained by normalizing the transmitting current and receiving area using the measured voltage. P is the transmitting magnetic moment, and μ0 is the free permeability.

[0104] Calculate sampling time t i Background signal S below i :

[0105]

[0106] Where μ0 is the vacuum permeability and P is the emission magnetic moment.

[0107] In one embodiment, the equivalent assessment of aquatic anomaly signals involves approximating and simplifying complex electromagnetic induction phenomena to obtain a model that can be directly described using analytical formulas. During power supply, the transmitting part of the device establishes a constant magnetic field in space. After the transmitting part stops supplying power, the spatial magnetic field induced by the device disappears instantaneously. However, according to the law of electromagnetic induction, the spatial magnetic field does not disappear immediately; 'eddy currents' are induced in the medium to maintain the previous magnetic field. The 'eddy currents' are related to the resistivity of the medium and gradually weaken over time until they disappear. According to research, the magnetic field generated by the eddy currents can be approximated by a magnetic dipole. Figure 7 A schematic diagram of the equivalent magnetic dipole of a spatial anomaly signal source is shown. The approximate expression for the magnetic field generated by the equivalent magnetic dipole of the initial eddy current in the anomaly is as follows:

[0108]

[0109] Among them, P M H is the magnetic moment of the equivalent magnetic dipole of the initial eddy current. z is the perpendicular component of the magnetic field, and r is the distance from the measurement point to the magnetic dipole.

[0110] From the above formula, it can be seen that the dipole magnetic field strength and P M And r is related. Since the secondary field gradually decays, but the degree of decay of the secondary field is the same at the same time, it is only necessary to compare the amplitude of pure anomalies in different boreholes at the same time to establish the ratio relationship between the anomaly amplitude and the distance.

[0111] As the eddy currents generated by the anomalous body gradually decrease, the magnetic field produced by these eddy currents in space also gradually decays. According to the attenuation law of transient electromagnetic signals, the magnetic field excited by the loop source follows the law of t... -5 / 2 The velocity decays, therefore, the general rule for the change of the secondary field with time is:

[0112]

[0113] Wherein, C is a coefficient related to the electrical distribution of the overall surrounding rock and the anomalous body, and this value is a constant for different measuring points and time t.

[0114] By making an equivalent approximation of the induced eddy current and using the analytical expression of the magnetic dipole field, the relationship between the received signal strength and the receiving distance and time can be established, providing a foundation for the three-dimensional spatial positioning technology of anomalies.

[0115] The dipole position (xo, yo) is unknown, and the following geometric relationship exists in the planar space:

[0116]

[0117]

[0118] Where d(1), d(2)...d(q-1), and d(q) are the distances between the same measuring point of q boreholes and the abnormal water body, respectively;

[0119] Based on the above, the equation relating the location of abnormal water bodies to the sequence of abnormal values ​​is:

[0120]

[0121] Where (x1,y1), (x2,y2), (x3,y3)…(x(q-1),y(q-1))…(xq,yq) are the coordinates of each borehole axis in the XOY plane, respectively. Figure 8 A rectangular coordinate system parallel to the borehole orientation is shown, where q represents the number of boreholes, (x0, y0) represents the location of the anomalous water body, i.e., the dipole location, and abv. 1ki ,abv 2ki ,abv 3ki …abv (q-1)ki ,abv qki These are the sampling times of the measuring point k in each borehole at sampling time t. i The corresponding abnormal data.

[0122] When solving the above equations, if there are 3 boreholes, the equations consist of 2 equations controlling 2 unknowns, and there is a unique solution. When there are more than 3 boreholes, the equations consist of multiple equations controlling 2 unknowns, and there is a solution with minimum error. In both cases, the values ​​of the unknown variables xo and yo, i.e. the location of the abnormal water body, can be obtained by iterative method.

[0123] In one embodiment, based on the distribution law of the anomalous field, the maximum value of the pure anomalous signal coincides with the borehole depth where the anomalous body is located. The maximum value points of the pure anomalous signal in the three boreholes can determine a plane, and the center point of the magnetic dipole equivalent to the water-bearing body (which can be approximated as the center position of the anomalous body) must be located in this plane. Figure 9A planar relationship diagram of the equivalent magnetic dipole and the borehole is shown. The magnetic dipole generates a magnetic field in space. Based on the anomalous amplitude of the dipole at its maximum amplitude position within the borehole, the dipole's location, i.e., the center position of the anomalous water-bearing body, can be determined. Therefore, in this embodiment, step S5, based on the pure anomaly multi-track map corresponding to each borehole, extracts the anomalous data of measuring points with the same number in all boreholes at each sampling time to form an anomaly value sequence, which may include:

[0124] Step S51: Based on the pure anomaly multi-track map corresponding to each borehole, determine at least one maximum point of all curves in each borehole, and the measurement point corresponding to the maximum point; the number of maximum points is the same as the number of abnormal water bodies.

[0125] Here, the pure anomaly multi-track plot corresponding to each borehole includes multiple curves at multiple sampling times. The distribution trends of the multiple curves are basically consistent. At least one maximum range can be determined based on the multiple curves, and then the mean of the maximum range can be obtained as a maximum point.

[0126] Step S52: For each borehole, the measuring points corresponding to the maximum value points are sorted in ascending order according to the depth corresponding to the measuring points to obtain the maximum value measuring point sequence for each borehole.

[0127] Step S53: Select the first measurement point in the maximum value measurement point sequence as the current measurement point, and determine the sampling time when the abnormal data of the current measurement point is the largest, denoted as the appropriate sampling time t. top And extract all boreholes at the current measuring point at the appropriate sampling time t. top The corresponding abnormal data form an outlier sequence. Here, the sampling time at which the maximum abnormal data occurs at the same measuring point in different boreholes is consistent, denoted as the appropriate sampling time t. top .

[0128] Step S54, return to step S53, select the next measurement point in the maximum measurement point sequence as the current measurement point; finally obtain the outlier sequence of each measurement point in the maximum measurement point sequence at the appropriate sampling time; each outlier sequence is used to construct the equation between the center position of each abnormal water body and each outlier sequence; the equation is used to obtain the center position of each abnormal water body.

[0129] Step S55: Extract the abnormal data corresponding to each measuring point of the maximum value measuring point sequence in all boreholes at each remaining sampling time, and construct the abnormal value sequence of each measuring point of the maximum value measuring point sequence at each remaining sampling time;

[0130] Step S56: Extract the abnormal data corresponding to each measuring point in all boreholes except for the measuring points in the maximum value measuring point sequence at each sampling time, and form the abnormal value sequence of each other measuring point at each sampling time.

[0131] In this embodiment, the measurement point sequence of each borehole can be obtained first. Based on the maximum value measurement point sequence and appropriate sampling times, an outlier sequence can be constructed. Based on the outlier sequence, an equation for solving the center location of at least one anomalous water body can be constructed. Then, based on the outlier sequences of other measurement points at other sampling times, equations for solving other locations besides the center location can be constructed. Finally, the overall spatial distribution of all anomalous water bodies is obtained. Figure 10 A general spatial distribution map of the abnormal water bodies is shown.

[0132] Figure 11 The inversion results for the three components of a single aperture are shown in the comparison diagram with the model. Figure 12 A comparison diagram of the joint inversion results of Z-component multi-well data and the model location is shown. Spatially, the inversion results of single-well data are distributed in an 'arc' shape along the borehole, and part of them match the model location. This is mainly due to the accurate depth calculated by the Z-component, while the orientation determined by the horizontal components X and Y has a certain error. However, by using Z-component multi-well data, the scale of the inversion results is greatly reduced, the location basically matches the model, and the accuracy is significantly improved.

[0133] Using a single-well three-component measurement method, the current detection distance is generally less than 30m, and the accuracy is limited. However, when using Z-component multi-well joint detection, Figure 13 A schematic diagram of the multi-pore connection detection distance is shown. (For example...) Figure 13 As shown, the method of this application can extend the precise exploration range to about 35m, greatly improving the exploration and positioning accuracy and, to a certain extent, increasing the exploration control distance.

[0134] Based on the same inventive concept as the multi-hole combined transient electromagnetic probing method for three-dimensional spatial positioning of abnormal water bodies, this embodiment also provides a corresponding multi-hole combined transient electromagnetic probing device for three-dimensional spatial positioning of abnormal water bodies. Figure 14 A structural block diagram of a multi-hole combined transient electromagnetic probing three-dimensional spatial positioning device for locating abnormal water bodies according to an embodiment of this application is shown. The device includes:

[0135] The transient electromagnetic signal acquisition module 141 is used to acquire transient electromagnetic signal data of each measuring point in each borehole arranged in the target area at multiple sampling times; there are multiple boreholes arranged in the target area that are parallel to each other in space, and the number of boreholes is not less than 3; multiple measuring points are set in each borehole, and the measuring points with the same number in the multiple boreholes have the same depth;

[0136] The original multi-track plot acquisition module 142 is used to obtain the original multi-track plot corresponding to each borehole based on the transient electromagnetic signal data of each measuring point in each borehole at multiple sampling times. The original multi-track plot includes multiple curves, and each curve is composed of transient electromagnetic signal data of all measuring points at a certain sampling time.

[0137] Background signal determination module 143 is used to determine the background signal for each sampling time corresponding to each borehole based on the relationship between the apparent resistivity of the formation background and the background signal at each sampling time of each borehole.

[0138] The pure anomaly multi-track map acquisition module 144 is used to remove the background signal at each sampling time corresponding to each borehole from the original multi-track map corresponding to each borehole to obtain the pure anomaly multi-track map corresponding to each borehole. The pure anomaly multi-track map includes multiple curves, and each curve is composed of the abnormal data of all measurement points at a certain sampling time.

[0139] The outlier sequence construction module 145 is used to extract outlier data from measuring points with the same number in all boreholes at each sampling time based on the pure outlier multi-track map corresponding to each borehole, thus forming an outlier sequence A. ki ={abv 1ki ,abv 2ki ,…abv jki …abv qki}, where A ki For the measurement point numbered k at sampling time t i The corresponding outlier sequence, abv jki For the measuring point numbered k in the j-th borehole at sampling time t i Abnormal data, where q is the number of boreholes;

[0140] Equation construction module 146 is used to construct equations for the location of abnormal water bodies and the sequence of abnormal values ​​based on the sequence of abnormal values ​​corresponding to each sampling time of measuring points with the same number.

[0141] The solver module 147 is used to solve the equations and obtain the location of the abnormal water bodies at each sampling time for the measuring points with the same number, i.e., the spatial distribution of the abnormal water bodies.

[0142] The multi-hole combined transient electromagnetic probing three-dimensional spatial positioning device for abnormal water bodies in this embodiment has the same inventive concept as the multi-hole combined transient electromagnetic probing three-dimensional spatial positioning method for abnormal water bodies described above. Therefore, the specific implementation of this device can be found in the embodiment section of the multi-hole combined transient electromagnetic probing three-dimensional spatial positioning method for abnormal water bodies described above, and its technical effects correspond to the technical effects of the above method, so it will not be repeated here.

[0143] This application provides a computer-readable storage medium storing a computer program. When the computer program is executed by a processor, it implements the above-described method for three-dimensional spatial positioning of abnormal water bodies using multi-hole combined transient electromagnetic exploration.

[0144] This application provides a computer program product, including a computer program / instruction, which is executed by a processor. The method for three-dimensional spatial positioning of abnormal water bodies using transient electromagnetic probing with multi-hole drilling is also described.

[0145] In summary, this application has the following technical effects:

[0146] To improve the accuracy of the detection results, this application employs joint exploration using multiple boreholes. After obtaining the observation data, the background signal is first extracted to obtain the pure anomalous signal generated by the water-bearing anomaly. By finding the extreme values ​​at the same depth on multiple boreholes, the center position of the water-bearing anomaly is determined using a three-dimensional spatial positioning method combined with the borehole Z-component signals. Similar processing is performed on anomalous signals at other depths and measurement times to finally obtain the spatial distribution results of the anomaly. Since the use of X and Y components with relatively low signal strength is avoided, the obtained results are more accurate and reliable.

[0147] The above descriptions are merely various embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A three-dimensional spatial positioning method for anomaly water bodies using multi-hole combined transient electromagnetic detection, characterized in that, include: Acquire transient electromagnetic signal data at multiple sampling times for each measuring point in each borehole in the target area; The target area is provided with a plurality of boreholes that are parallel to each other in space, and the number of boreholes is not less than 3; each borehole is provided with a plurality of measuring points, and the measuring points with the same number in the plurality of boreholes have the same depth; Based on the transient electromagnetic signal data of each measuring point in each borehole at multiple sampling times, the original multi-track diagram corresponding to each borehole is obtained; the original multi-track diagram includes multiple curves, and each curve is composed of transient electromagnetic signal data of all measuring points at a certain sampling time; Based on the relationship between the apparent resistivity of the formation background and the background signal at each sampling time for each borehole, the background signal at each sampling time for each borehole is determined. Remove the background signal at each sampling time from the original multi-track map corresponding to each borehole to obtain a pure anomaly multi-track map corresponding to each borehole; the pure anomaly multi-track map includes multiple curves, and each curve is composed of the abnormal data of all measurement points at a certain sampling time. Based on the pure anomaly multi-track map corresponding to each borehole, the anomaly data of the measuring points with the same number in all boreholes at each sampling time are extracted to form an outlier sequence A. ki ={abv 1ki ,abv 2ki ...abv jki ...abv qki }, where A ki For the measurement point numbered k at sampling time t i The corresponding outlier sequence, abv jki For the measuring point numbered k in the j-th borehole at sampling time t i Abnormal data, where q is the number of boreholes; Based on the sequence of outliers corresponding to each sampling time for measuring points with the same number, an equation is constructed relating the location of the abnormal water body to the sequence of outliers. Solving the equation yields the location of the abnormal water bodies at each sampling time for the measuring points with the same number, i.e., the spatial distribution of the abnormal water bodies.

2. The method as described in claim 1, characterized in that, in, Based on the relationship between the apparent resistivity of the formation background and the background signal at each sampling time for each borehole, the background signal at each sampling time for each borehole is determined, including: Calculate the apparent resistivity of the formation background at sampling time ti Where M is the number of measuring points in the borehole, j is the measuring point number, and ρs(i,j) is the sampling time t. i The resistivity value reflected by the signal data collected at the j-th measuring point; Calculate sampling time t i Background signal S i : Where μ0 is the vacuum permeability and P is the emission magnetic moment.

3. The method as described in claim 1, characterized in that, in, Based on the pure anomaly multi-track map corresponding to each borehole, the anomaly data of all boreholes with the same number at each sampling time are extracted to form an outlier sequence, including: Step S51: Based on the pure anomaly multi-track map corresponding to each borehole, determine at least one maximum point of all curves in each borehole, and the measurement point corresponding to the maximum point; the number of maximum points is the same as the number of abnormal water bodies. Step S52: For each borehole, the measuring points corresponding to the maximum value points are sorted in ascending order of the depth corresponding to the measuring points to obtain the maximum value measuring point sequence for each borehole. Step S53: Select the first measurement point in the maximum value measurement point sequence as the current measurement point, and determine the sampling time when the abnormal data of the current measurement point is the largest, denoted as the appropriate sampling time t. top And extract all boreholes at the current measuring point at the appropriate sampling time t. top The corresponding abnormal data form an outlier sequence; Step S54, return to step S53, select the next measuring point in the maximum value measuring point sequence as the current measuring point; finally obtain the outlier sequence of each measuring point in the maximum value measuring point sequence at a suitable sampling time; each outlier sequence is used to construct an equation between the center position of each abnormal water body and each outlier sequence; the equation is used to obtain the center position of each abnormal water body; Step S55: Extract the abnormal data corresponding to each measuring point of the maximum value measuring point sequence in all boreholes at each remaining sampling time, to form the abnormal value sequence of each measuring point of the maximum value measuring point sequence at each remaining sampling time; Step S56: Extract the abnormal data corresponding to each measuring point in all boreholes except for the measuring points in the maximum value measuring point sequence at each sampling time, and form the abnormal value sequence of each other measuring point at each sampling time.

4. The method as described in claim 1, characterized in that, The equation relating the location of the abnormal water body to the sequence of abnormal values ​​is as follows: Where (x1, y1), (x2, y2), (x3, y3)...(x(q-1), y(q-1))...(xq, yq) are the coordinates of each borehole axis in the XOY plane, q is the number of boreholes, (x0, y0) is the location of the abnormal water body, and abv 1ki ,abv 2ki ,abv 3ki ...abv (q-1)ki ,abv qki These are the sampling times of the measuring point k in each borehole at sampling time t. i The corresponding abnormal data.

5. A three-dimensional spatial positioning device for detecting abnormal water bodies using multi-hole combined transient electromagnetic detection, characterized in that, include: The transient electromagnetic signal acquisition module is used to acquire transient electromagnetic signal data of each measuring point in each borehole in the target area at multiple sampling times; The target area is provided with a plurality of boreholes that are parallel to each other in space, and the number of boreholes is not less than 3; each borehole is provided with a plurality of measuring points, and the measuring points with the same number in the plurality of boreholes have the same depth; The original multi-track mapping acquisition module is used to obtain the original multi-track mapping corresponding to each borehole based on the transient electromagnetic signal data of each measuring point in each borehole at multiple sampling times; the original multi-track mapping includes multiple curves, and each curve is composed of transient electromagnetic signal data of all measuring points at a certain sampling time; The background signal determination module is used to determine the background signal for each borehole at each sampling time based on the relationship between the apparent resistivity of the formation background and the background signal at each sampling time for each borehole. The pure anomaly multi-track map acquisition module is used to remove the background signal at each sampling time corresponding to each borehole from the original multi-track map corresponding to each borehole to obtain the pure anomaly multi-track map corresponding to each borehole; the pure anomaly multi-track map includes multiple curves, and each curve is composed of the abnormal data of all measurement points at a certain sampling time. The outlier sequence construction module is used to extract outlier data from all boreholes with the same measurement point at each sampling time based on the pure outlier multi-track map corresponding to each borehole, thus constructing an outlier sequence A. ki ={abv 1ki ,abv 2ki ...abv jki ...abv qki }, where A ki For the measurement point numbered k at sampling time t i The corresponding outlier sequence, abv jki For the measuring point numbered k in the j-th borehole at sampling time t i Abnormal data, where q is the number of boreholes; The equation construction module is used to construct equations relating the location of the abnormal water body to the abnormal value sequence at each sampling time, based on the abnormal value sequence corresponding to the measuring points with the same number. The solution module is used to solve the equation to obtain the location of the abnormal water body at each sampling time for the measuring points with the same number, i.e., the spatial distribution of the abnormal water body.

6. The apparatus as claimed in claim 5, characterized in that, The background signal determination module is further configured to: Calculate sampling time t i Apparent resistivity of the underlying strata Where M is the number of measuring points in the borehole, j is the measuring point number, and ρs(i,j) is the sampling time t. i The resistivity value reflected by the signal data collected at the j-th measuring point; Calculate sampling time t i Background signal S i : Where μ0 is the vacuum permeability and P is the emission magnetic moment.

7. The apparatus as claimed in claim 5, characterized in that, The outlier sequence construction module is also used for: Step S51: Based on the pure anomaly multi-track map corresponding to each borehole, determine at least one maximum point of all curves in each borehole, and the measurement point corresponding to the maximum point; the number of maximum points is the same as the number of abnormal water bodies. Step S52: For each borehole, the measuring points corresponding to the maximum value points are sorted in ascending order of the depth corresponding to the measuring points to obtain the maximum value measuring point sequence for each borehole. Step S53: Select the first measurement point in the maximum value measurement point sequence as the current measurement point, and determine the sampling time when the abnormal data of the current measurement point is the largest, denoted as the appropriate sampling time t. top And extract all boreholes at the current measuring point at the appropriate sampling time t. top The corresponding abnormal data form an outlier sequence; Step S54, return to step S53, select the next measuring point in the maximum value measuring point sequence as the current measuring point; finally obtain the outlier sequence of each measuring point in the maximum value measuring point sequence at a suitable sampling time; each outlier sequence is used to construct an equation between the center position of each abnormal water body and each outlier sequence; the equation is used to obtain the center position of each abnormal water body; Step S55: Extract the abnormal data corresponding to each measuring point of the maximum value measuring point sequence in all boreholes at each remaining sampling time, to form the abnormal value sequence of each measuring point of the maximum value measuring point sequence at each remaining sampling time; Step S56: Extract the abnormal data corresponding to each measuring point in all boreholes except for the measuring points in the maximum value measuring point sequence at each sampling time, and form the abnormal value sequence of each other measuring point at each sampling time.

8. The apparatus as claimed in claim 5, characterized in that, The equation relating the location of the abnormal water body to the sequence of abnormal values ​​is as follows: Where (x1, y1), (x2, y2), (x3, y3)...(x(q-1), y(q-1))...(xq, yq) are the coordinates of each borehole axis in the XOY plane, q is the number of boreholes, (x0, y0) is the location of the abnormal water body, and abv 1ki ,abv 2ki ,abv 3ki ...abv (q-1)ki ,abv qki These are the sampling times of the measuring point k in each borehole at sampling time t. i The corresponding abnormal data.

9. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program, which, when executed by a processor, implements the three-dimensional spatial positioning method for transient electromagnetic probing of abnormal water bodies using multiple boreholes combined, as described in any one of claims 1-4.

10. A computer program product, characterized in that, It includes a computer program / instruction, which, when executed by a processor, implements the three-dimensional spatial positioning method for transient electromagnetic probing of abnormal water bodies using multiple boreholes combined, as described in any one of claims 1-4.

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