Borehole transient electromagnetic method-based three-dimensional expansion processing method and system

Abstract

A borehole transient electromagnetic method-based three-dimensional expansion processing method, comprising: collecting measurement information at each measurement point inside a borehole to be measured, the measurement information comprising a secondary field induced electromotive force and a roll angle (S10); for each measurement point, establishing an expanded view by using the roll angle as the abscissa and using the secondary field induced electromotive force as the ordinate (S20); and, when an electromotive force signal in the expanded view is a negative response, according to a roll angle transformation formula, converting the electromotive force signal into a positive response, so as to obtain measurement transformation information at each measurement point (S30). The method solves processing problems for detecting negative induced electromotive force responses by means of borehole transient electromagnetic methods, obtains measurement transformation information of measurement points which contains negative electromotive force signals, and can improve the accuracy of anomalous body localization. The present invention further relates to a borehole transient electromagnetic method-based three-dimensional expansion processing system.

Description

A three-dimensional expansion processing method and system for drilling transient electromagnetic method Technical Field

[0001] The present invention relates to the field of surveying technology, and in particular to a three-dimensional expansion processing method and system for a borehole transient electromagnetic method. Background Art

[0002] The borehole transient electromagnetic method is proposed on the basis of traditional well logging technology and mine transient electromagnetic method. Combining the advantages of both, it conducts all-round transient electromagnetic detection in the limited space of the borehole, so as to achieve the purpose of using the underground coal mine borehole to understand the lithology of the borehole and its surrounding water-richness, structure and other issues. Compared with the traditional transient electromagnetic method, the advantages of applying the mine transient electromagnetic method in the borehole to explore the geological conditions around the borehole are mainly reflected in the following three aspects: (1) The detection of the borehole transient electromagnetic method can avoid the interference caused by the metal support of the tunnel and improve the signal-to-noise ratio of the transient electromagnetic signal; (2) The probe is sent into the borehole for detection, which is closer to the abnormal body, the abnormal information distance is short, the loss is small, the secondary field diffusion is small, and the resolution is higher; (3) The water damage anomaly that is not revealed in the borehole can be discovered by the borehole transient electromagnetic method, which expands the control radius of the borehole and improves the utilization rate of the borehole.

[0003] However, there are still some technical problems in the current hole transient electromagnetic detection technology:

[0004] (1) The borehole detection is a full-space response. The transient electromagnetic signal response curve will be different depending on the orientation of the anomaly relative to the probe, and even a negative response that is not conducive to the calculation of the resistivity value will occur. In related technologies, such as the method for detecting radial water-bearing anomalies in coal mine boreholes proposed in the Chinese invention patent application document with application publication number CN104090306A, the negative response cannot be effectively utilized in the process of locating the anomaly. (2) Only the approximate angle of the borehole where the anomaly is located can be located, and the distance of the anomaly from the center of the borehole cannot be determined. The above technical difficulties restrict the scope of application and efficiency of the borehole transient electromagnetic method.

[0005] Summary of the Invention

[0006] The technical problem to be solved by the present invention is how to convert the negative response into effective information that is beneficial to the resistivity value calculation during the abnormal body positioning process through a three-dimensional expansion processing method.

[0007] The present invention solves the above technical problems through the following technical means:

[0008] The present invention proposes a three-dimensional expansion processing method of a borehole transient electromagnetic method, the method comprising:

[0009] Measurement information of each measuring point in the borehole to be measured is collected, the measurement information including the secondary field induced electromotive force and the roll angle; for each measuring point, an expansion diagram is established with the roll angle as the horizontal coordinate and the secondary field induced electromotive force as the vertical coordinate; when there is an electromotive force signal with a negative response in the expansion diagram, the electromotive force signal is converted into a positive response according to the conversion formula of the roll angle, thereby obtaining measurement transformation information of each measuring point.

[0010] Furthermore, the collecting of measurement information of each measuring point in the borehole to be measured includes:

[0011] When the transient electromagnetic detection device is sent into and / or out of the borehole to be measured by using the push rod, point measurement is performed according to the set step distance to obtain measurement information of each measurement point.

[0012] Furthermore, the transient electromagnetic detection device is rotatably connected to the push rod, and the method also includes: when the transient electromagnetic detection device is pushed or withdrawn to a certain measuring point position by using the push rod, the transient electromagnetic detection device is rotated by a specified angle to measure the lateral information of the drilling at the measuring point position.

[0013] Furthermore, before collecting the measurement information of each measuring point in the borehole to be measured, the method further includes:

[0014] When the roll angle γ is 0°, the right side is 90°, and the left side is -90°. The transient electromagnetic detection device is calibrated to have 0 degrees vertically upward and +-180 degrees vertically downward, and a first coordinate system is established.

[0015] The first receiving coil is set to be perpendicular to the axial direction of the transient electromagnetic detection device along a horizontal plane, and the right direction is the positive direction of the X axis of the first coordinate system, and the second receiving coil is set to be perpendicular to the horizontal plane and upward, and the positive direction of the Z axis of the first coordinate system;

[0016] An iron object is placed as a known abnormal object in any quadrant of the first coordinate system, and the X-component induced electromotive force and the Z-component induced electromotive force are measured by the first receiving coil and the second receiving coil respectively;

[0017] When the X-component induced electromotive force and / or the Z-component induced electromotive force do not conform to the quadrant, the direction of the X-component and / or the direction of the Z-component are adjusted to make the direction of the induced electromotive force conform to the quadrant.

[0018] Furthermore, when there is an electromotive force signal with a negative response in the expanded diagram, the electromotive force signal is converted into a positive response according to the conversion formula of the roll angle to obtain measurement conversion information of each measuring point, including:

[0019] When a component electromotive force signal in the expanded diagram has a negative response, the roll angle is transformed to convert the negative electromotive force signal into a positive response, wherein the transformation formula of the roll angle is:

[0020] When 0°<γ<180°, γ'=γ-180°

[0021] When -180°<γ<0°, γ'=180°+γ

[0022] Where: γ represents the measured roll angle, and γ' represents the transformed roll angle.

[0023] Furthermore, for processing the induced electromotive force signal of the positive response, the method further includes:

[0024] The induced electromotive force signal of the positive response is divided into a high voltage region and a low voltage region;

[0025] Interpolation operations are performed on high-voltage areas and low-voltage areas respectively, and multiple measuring points in the corresponding areas are smoothly connected to form a multi-channel curve.

[0026] Furthermore, when there is an electromotive force signal with a negative response in the expanded diagram, the electromotive force signal is converted into a positive response according to the roll angle conversion formula to obtain measurement conversion information of each measuring point. The method further includes: locating the direction and distance of the abnormal body based on the measurement conversion information of all measuring points, including:

[0027] Based on the measurement transformation information of all measuring points, a three-dimensional electromotive force data centered on the drill hole is formed;

[0028] The position and distance of the abnormal body are located based on the three-dimensional electromotive force data.

[0029] Furthermore, the measurement transformation information based on all the measuring points forms a three-dimensional electromotive force data centered on the borehole, including:

[0030] Establish a second coordinate system with the X-axis of the first coordinate system being the transformed roll angle γ', the Y-axis being the hole depth or actual footage, and the Z-axis being the transformed induced electromotive force value;

[0031] In the second coordinate system, the measurement transformation information of all the measuring points is combined along the depth direction of the borehole to be measured according to the set spacing to obtain the three-dimensional electromotive force data after the borehole to be measured is expanded in the form of a roll angle.

[0032] Furthermore, the positioning of the orientation and distance of the abnormal body based on the three-dimensional electromotive force data includes: processing the three-dimensional electromotive force data using a known resistivity calculation method to obtain two-dimensional and three-dimensional spatial distributions of resistivity of all measuring points, and calculating a three-dimensional resistivity data volume centered on the borehole;

[0033] Extracting a two-dimensional resistivity value profile from the three-dimensional resistivity data volume according to an arbitrarily specified roll angle;

[0034] Based on the two-dimensional resistivity value profile, the geological conditions at any specified orientation and any specified distance of the borehole to be tested are determined.

[0035] In addition, the present invention also proposes a three-dimensional expansion processing system for a borehole transient electromagnetic method, the system comprising: an acquisition module for acquiring measurement information of each measuring point in the borehole to be measured, the measurement information including secondary field induced electromotive force and roll angle;

[0036] An expansion diagram construction module is used to establish an expansion diagram for each measuring point, using the roll angle as the abscissa and the secondary field induced electromotive force as the ordinate;

[0037] The electromotive force conversion module is used to convert the electromotive force signal into a positive response according to the conversion formula of the roll angle when there is a negative electromotive force signal in the expansion diagram, so as to obtain measurement conversion information of each measuring point.

[0038] Furthermore, the system further includes a calibration module, which includes:

[0039] A first coordinate system establishing unit is used to establish a first coordinate system with a roll angle γ of 0°, a right side of 90°, a left side of -90°, a vertical upward direction of the transient electromagnetic detection device of 0°, and a vertical downward direction of +-180°;

[0040] A setting unit is used to set the first receiving coil to be perpendicular to the axial direction of the transient electromagnetic detection device along a horizontal plane, with the right direction being the positive direction of the X axis of the first coordinate system, and the second receiving coil to be perpendicular to the horizontal plane and upwards being the positive direction of the Z axis of the first coordinate system; a measuring unit is used to place an iron object as a known anomaly in any quadrant of the first coordinate system, and measure the X-component induced electromotive force and the Z-component induced electromotive force respectively through the first receiving coil and the second receiving coil;

[0041] The calibration unit is configured to adjust the direction of the X component and / or the direction of the Z component to conform to the quadrant when the X component induced electromotive force and / or the Z component induced electromotive force do not conform to the quadrant.

[0042] The advantages of the present invention are:

[0043] (1) The present invention is directed to the measurement information of each measuring point in the borehole. The horizontal coordinate of the original measurement signal is time, and the vertical coordinate is the secondary field induced electromotive force. An expansion diagram is established by using the roll angle as the horizontal coordinate and the secondary field induced electromotive force as the vertical coordinate. If there is an electromotive force signal with a negative response in the expansion diagram, the roll angle conversion formula is used to convert the electromotive force signal into effective information that is beneficial to the calculation of the resistivity value, that is, a positive response, so as to facilitate the positioning of the orientation and distance of the abnormal body based on the electromotive force signals of all measuring points.

[0044] (2) In the present invention, the negative electromotive force signal is converted into a positive electromotive force signal, which is combined with the originally positive electromotive force signal to determine the orientation of the abnormal body and the distance from the detection device. By expanding the borehole in a roll angle manner, the problem of processing the negative induced electromotive force response detected by the borehole transient electromagnetic method is fundamentally solved. By fully and effectively utilizing the negative electromotive force signal, the accuracy of the abnormal body positioning is improved, and the technical problem of inaccurate abnormal orientation positioning caused by the full space response is solved.

[0045] (3) Before collecting the measurement information of each measuring point in the borehole to be measured, the present invention first calibrates the detection device to ensure that the detection device can accurately collect the measurement information of each measuring point.

[0046] Additional aspects and advantages of the present invention will be set forth in part in the description which follows and, in part, will be obvious from the description which follows, or may be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] FIG1 is a schematic flow chart of a three-dimensional expansion processing method using a drilling transient electromagnetic method according to an embodiment of the present invention;

[0048] FIG2 is a schematic structural diagram of a dual transmitting coil according to an embodiment of the present invention;

[0049] FIG3 is a front view of the entire detection device after entering the borehole according to one embodiment of the present invention;

[0050] FIG4 is a vector decomposition diagram of detection accuracy and detection times corresponding to an embodiment of the present invention;

[0051] 5 is a diagram showing the cause of a negative response signal occurring in a hole transient and its transformation principle in one embodiment of the present invention;

[0052] FIG6 is a schematic diagram of actual measurement in one embodiment of the present invention;

[0053] 7 is a schematic diagram showing changes in a negative signal according to a roll angle according to an embodiment of the present invention;

[0054] FIG8 is a schematic diagram of an interpolation principle according to an embodiment of the present invention;

[0055] FIG9 is a regular diagram of the original induced electromotive force curve of the secondary field at measuring point 1 in one embodiment of the present invention;

[0056] FIG10 is a regular diagram of the original induced electromotive force curve of the secondary field at measuring point 2 in one embodiment of the present invention;

[0057] FIG11 is a roll angle expansion diagram after transformation of measuring point 2 in one embodiment of the present invention;

[0058] FIG12 is a regular diagram of the original induced electromotive force curve of the secondary field at measuring point three in one embodiment of the present invention;

[0059] FIG13 is an expanded view of the roll angle after three transformations of the measuring points in one embodiment of the present invention;

[0060] FIG14 is a regular diagram of the original induced electromotive force curve of the secondary field at measuring point four in one embodiment of the present invention;

[0061] FIG15 is an expanded view of the roll angle after the transformation of the measuring point four in one embodiment of the present invention;

[0062] FIG16 is a regular diagram of the original induced electromotive force curve of the secondary field at measuring point five in one embodiment of the present invention;

[0063] FIG17 is an expanded view of the roll angle after transformation of measuring point five in one embodiment of the present invention;

[0064] FIG18 is a three-dimensional spatial distribution diagram of all measuring points in one embodiment of the present invention;

[0065] FIG19 is a two-dimensional slice image extracted at a roll angle of -150° when drilling a hole in one embodiment of the present invention;

[0066] FIG20 is a two-dimensional slice image extracted at a roll angle of 30° when drilling a hole in one embodiment of the present invention;

[0067] FIG21 is a schematic structural diagram of a three-dimensional expansion processing system for a drilling transient electromagnetic method according to an embodiment of the present invention. DETAILED DESCRIPTION

[0068] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0069] As shown in FIG1 , the first embodiment of the present invention provides a method for three-dimensional expansion processing using a borehole transient electromagnetic method, the method comprising the following steps:

[0070] S10, collecting measurement information of each measuring point in the borehole to be measured, the measurement information including the secondary field induced electromotive force and the roll angle; S20, for each measuring point, creating an expansion diagram with the roll angle as the abscissa and the secondary field induced electromotive force as the ordinate;

[0071] S30 , when there is an electromotive force signal with a negative response in the developed diagram, convert the electromotive force signal into a positive response according to the roll angle conversion formula to obtain measurement conversion information of each measuring point.

[0072] In this embodiment, a transient electromagnetic detection device can be used to measure each measuring point in the borehole to be measured. For the measurement information of each measuring point in the borehole, an expansion diagram is established with the roll angle as the horizontal coordinate and the secondary field induced electromotive force as the vertical coordinate. If there is an electromotive force signal with a negative response in the expansion diagram, the roll angle conversion formula is used to convert the electromotive force signal into a positive response, so that the direction and distance of the abnormal body can be located based on the electromotive force signals of all measuring points.

[0073] In one embodiment, when collecting information of each measuring point in the borehole to be measured, a push rod and a transient electromagnetic detection device are used. The transient electromagnetic detection device is rotatably connected to the push rod. The transient electromagnetic detection device includes a dual transmitting coil, a roll angle measurement component, an in-hole transient collection component and at least two receiving coils, and there is an angle between the two receiving coils; the dual transmitting coil is connected to the transmitter, and the receiving coil is connected to the receiver.

[0074] The roll angle measuring component may be an inclinometer or an electronic compass, the in-hole transient acquisition component may be an AD acquisition device, and the transient electromagnetic detection device and the push rod are specifically connected by threads.

[0075] Specifically, the structure of a dual transmitting coil is shown in Figure 2. A dual transmitting coil is constructed by placing two coaxial transmitting coils within a cylinder and passing currents in opposite directions. The solid lines represent the wiring diagram of the dual transmitting coils, and the solid arrows indicate the direction of the currents. Following the right-hand screw law, the transmitting coils generate a magnetic field, as indicated by the dashed lines, with the dashed arrows indicating the direction of the magnetic field lines. This dual transmitting coil is equivalent to having a magnetic field source, similar to a point power source, at the center of the cylinder, emitting a primary field in the radial direction of the borehole.

[0076] Unlike the related art in which the transmitting device is placed at the borehole mouth, the transient electromagnetic detection device used in this embodiment is cylindrical in shape as a whole and is rotatably connected to the push rod. When performing point measurement, the push rod can be used to send the transient electromagnetic measuring device into the borehole, and point measurement can be performed during the process of entering and / or exiting the borehole.

[0077] Figure 3 is a front view of the entire device after entering the drilling hole. When the roll angle γ is 0°, the right side is 90 degrees, the left side is -90 degrees, the device is vertically upward at 0 degrees, and downward at +-180 degrees, a first coordinate system is established.

[0078] Of the two receiving coils, the first receiving coil is used to measure the X component of the induced electromotive force. The first receiving coil is perpendicular to the axial direction of the device along the horizontal plane and is positive to the right; the second receiving coil is used to measure the Z component of the induced electromotive force. The second receiving coil is perpendicular to the horizontal plane and is positive upward.

[0079] In one embodiment, the step S10 of collecting measurement information of each measuring point in the borehole to be measured is specifically as follows:

[0080] When the transient electromagnetic detection device is sent into and / or out of the borehole to be measured by using the push rod, point measurement is performed according to the set step distance to obtain measurement information of each measurement point.

[0081] It should be noted that, in this embodiment, when performing point measurement, point measurement can be performed according to a certain advance distance while the probe is inserted into the borehole to be measured until the bottom of the hole; or point measurement can be performed according to a certain retreat distance while the probe is withdrawn from the borehole; or point measurement can be performed according to a certain interval both during the process of the probe being inserted into the borehole to be measured and during the process of withdrawing from the borehole, thereby improving the detection accuracy by increasing the number of collected data points.

[0082] It should be understood that the footage used when the probe is sent into the borehole to be measured and the delay used when the probe is withdrawn from the borehole to be measured may be the same or different.

[0083] In one embodiment, the step S10 of collecting measurement information of each measuring point in the borehole to be measured further includes the following steps:

[0084] When the transient electromagnetic detection device is pushed to a certain measuring point by using the pushing rod, the transient electromagnetic detection device is rotated to measure the lateral information of the borehole at the measuring point.

[0085] This embodiment rotates the transient electromagnetic detection device to achieve multiple measurements at the same measuring point position to improve lateral resolution and ensure detection accuracy. As shown in Figure 4, through vector diagram analysis, it can be seen that when measuring once, 2 measurement values ​​are obtained, and the abnormal direction can be controlled within the range of 90°. By measuring twice, 4 measurement values ​​are obtained, and the abnormal range can be controlled within the range of 45°. By measuring three times, the abnormal direction can be controlled within the range of 30°. When it is necessary to rotate n times for measurement, 2n measuring points appear in the radial direction, and the data of 1n axial measuring points can be directly superimposed into one measuring point. The 2n radial points need to be expressed similarly by vector decomposition and forward modeling. At the same time, the second measurement should be 45°, and the third measurement should be 30°. That is, the optimal deflection angle β for n measurements is 90 / n.

[0086] In one embodiment, before step S10: collecting measurement information of each measuring point in the borehole to be measured, the method further includes:

[0087] When the roll angle γ is 0°, the right side is 90°, the left side is -90°, the vertical upward direction of the transient electromagnetic detection device is 0 degrees, and the vertical downward direction is +-180 degrees, a first coordinate system is established;

[0088] The first receiving coil is set to be perpendicular to the axial direction of the transient electromagnetic detection device along a horizontal plane, and the right direction is the positive direction of the X axis of the first coordinate system, and the second receiving coil is set to be perpendicular to the horizontal plane and upward, and the positive direction of the Z axis of the first coordinate system;

[0089] An iron object is placed as a known abnormal object in any quadrant of the first coordinate system, and the X-component induced electromotive force and the Z-component induced electromotive force are measured by the first receiving coil and the second receiving coil respectively;

[0090] When the X-component induced electromotive force and / or the Z-component induced electromotive force do not conform to the quadrant, the direction of the X-component and / or the direction of the Z-component are adjusted to conform to the quadrant.

[0091] It should be noted that if the iron object is placed in the first quadrant as a known abnormal body, the induced electromotive force values ​​measured by the two components are both positive. If they are not both positive, the direction of the negative electromotive force component is adjusted; if the iron object is placed in the third quadrant as a known abnormal body, the induced electromotive force values ​​measured by the two components are both negative. If the actual measurement results are not both negative, the two induced electromotive force components are adjusted to be negative.

[0092] Preferably, in this embodiment, the ironware is placed in the first quadrant or the third quadrant to calibrate the detection device, which has the best effect.

[0093] In one embodiment, step S30: when there is a negative response of the electromotive force signal in the expanded diagram, converting the electromotive force signal into a positive response according to the roll angle conversion formula to obtain measurement conversion information of each measuring point includes:

[0094] When a component electromotive force signal in the expanded diagram has a negative response, the roll angle is transformed to convert the negative electromotive force signal into a positive response, wherein the transformation formula of the roll angle is:

[0095] When 0°<γ<180°, γ'=γ-180°

[0096] When -180°<γ<0°, γ'=180°+γ

[0097] Where: γ represents the measured roll angle, and γ' represents the transformed roll angle.

[0098] Specifically, the reason for the negative response signal in the hole transient and its transformation process are as follows: the primary magnetic field is directed radially. When entering the emission intermission period, according to Lenz's law, the secondary magnetic field induced by the low-resistance anomaly will hinder the disappearance of the primary magnetic field. As shown in Figure 5, ch1 is directly opposite the anomaly. To prevent the disappearance of the primary magnetic field, it must produce a secondary magnetic field with the same direction as the primary magnetic field. In reality, ch1 and ch4 are in the same direction, so only one channel is required (such as the X-component channel or the Z-component channel). Because the coil has a direction, according to a prior agreement, the right direction is defined as positive. In the anomaly shown in Figure 5, the measured induced electromotive force is positive; if the anomaly is in the opposite direction, the measured induced electromotive force is negative. A second coordinate system is established, with γ' as the horizontal coordinate of the expanded diagram and the induced electromotive force as the vertical coordinate. After replacing γ with γ' on the expanded diagram, the negative induced electromotive force should become positive (vector relationship) and be placed in the expanded diagram.

[0099] For example, when the abnormal body is located on the positive half axis of the Z component and the positive half axis of the X component, the secondary field induced electromotive force curve is positive. When the abnormal body is located on the negative half axis, the secondary field induced electromotive force curve is negative. To ensure that the signal is positive, the signal is transformed according to the measured roll angle γ. The transformation method is as follows:

[0100] When the induced electromotive force signal is positive: the changed roll angle γ' = the actual roll angle γ;

[0101] When the induced electromotive force signal is negative: Taking the X-component induced electromotive force as an example, the roll angle conversion formula is used for conversion to obtain the changed roll angle γ'.

[0102] It should be understood that when the Z-component induced electromotive force is negative, the signal conversion process is the same.

[0103] It should be noted that the signal collected by the transient electromagnetic method is the attenuation curve of the secondary field signal changing with time, and the secondary field signal collected by the transient electromagnetic equipment in the hole will appear positive or negative depending on the abnormal orientation. According to the attenuation curve, a time point can be artificially specified. Based on this point, the absolute value of the negative value to be converted is taken, and it is changed into a positive signal at the corresponding position through the roll angle formula.

[0104] It should be noted that in the traditional time domain transient electromagnetic method, the measurement information of a single measuring point can be reflected by the attenuation of the induced electromotive force values ​​of multiple measuring points over time, and the multi-track curves between multiple measuring points are formed according to linear interpolation (the time of the same measuring point at different measuring points is the same, but the measured induced electromotive force values ​​are different). In the expanded diagram, by expanding the information of a certain measuring point with the borehole roll angle, the measurement information of each roll angle can be reflected by the attenuation of the induced electromotive force of multiple measuring points over time, and the multi-track curves between different roll angles are formed according to linear interpolation.

[0105] In one embodiment, for the induced electromotive force signal of the positive response, the method further includes:

[0106] The induced electromotive force signal of the positive response is divided into a high voltage region and a low voltage region;

[0107] Interpolation operations are performed on high-voltage areas and low-voltage areas respectively, and multiple measuring points in the corresponding areas are smoothly connected to form a multi-channel curve.

[0108] It should be noted that the positive response induced electromotive force signal here includes the positive response induced electromotive force signal itself or the positive response induced electromotive force converted from the negative response induced electromotive force.

[0109] It should be noted that the overall secondary field induced electromotive force value can be artificially defined as a low voltage zone below 10 μV and a high voltage zone greater than or equal to 10 μV.

[0110] Specifically, as shown in FIG6 , when the in-hole transient electromagnetic device is placed on the reinforced concrete ground for detection, the values ​​of two components (Z, X) can be obtained in one measurement. At this time, the secondary fields corresponding to the response curves of the measured Z and X components are both negative.

[0111] As shown in Figure 7, when the anomaly is located on the negative half axis, the corresponding induced electromotive force is negative. To convert the negative value into a positive value, the Z component -30° induced electromotive force can be equivalent to the Z component 150°, and the X component 60° induced electromotive force can be equivalent to the X component -120°.

[0112] Therefore, the points where the induced electromotive force is negative can be converted into positive values ​​of the corresponding angles through the roll angle equivalent, and the previously negative angles can be artificially set as low voltage points (high resistance). For positive induced electromotive forces, multiple measurement points are smoothly connected through interpolation to form a multi-channel curve. During the specific interpolation, separate interpolation operations should be performed for high and low voltage areas, as shown in Figure 8.

[0113] In one embodiment, in step S30, when there is an electromotive force signal with a negative response in the developed diagram, the electromotive force signal is converted into a positive response according to the roll angle conversion formula to obtain measurement conversion information for each measuring point, the method further includes:

[0114] S40. Locate the orientation and distance of the abnormal body based on the measurement transformation information of all measurement points.

[0115] The step S40: locating the position and distance of the abnormal body based on the measurement transformation information of all measurement points, specifically includes the following steps:

[0116] S41, forming three-dimensional electromotive force data centered on the drill hole based on the measurement transformation information of all the measuring points;

[0117] S42. Locate the position and distance of the abnormal body based on the three-dimensional electromotive force data.

[0118] In this embodiment, the negative electromotive force signal is converted into a positive electromotive force signal, which is combined with the originally positive electromotive force signal to determine the orientation of the abnormal body and the distance from the detection device. By expanding the borehole in a roll angle manner, the problem of processing the negative induced electromotive force response detected by the borehole transient electromagnetic method is fundamentally solved. By fully and effectively utilizing the negative electromotive force signal, the accuracy of the abnormal body positioning is improved, and the technical problem of inaccurate abnormal orientation positioning caused by the full space response is solved.

[0119] In one embodiment, the step S41 of forming three-dimensional electromotive force data centered on the borehole based on the measurement transformation information of all measurement points includes the following steps:

[0120] Establish a second coordinate system with the X-axis of the first coordinate system being the transformed roll angle γ', the Y-axis being the hole depth or actual footage, and the Z-axis being the induced electromotive force value;

[0121] In the second coordinate system, the measurement transformation information of all the measuring points is combined according to the set spacing along the depth direction of the borehole to be measured to obtain the three-dimensional electromotive force data after the borehole to be measured is expanded in the form of a roll angle.

[0122] It should be noted that for the same measuring point, when there are only two measuring points with the X and Z components measured once, the abnormal interpolation rule uses the 4-way limit method; when there are four measuring points with two measurements, linear interpolation is used, which is more convenient when there are more than four measuring points.

[0123] The following five typical measurement examples are used to further illustrate this. For ease of drawing, multiple measurement curves in the figure are replaced by a thick solid line. In the expanded diagram, the solid thin arrows represent the actual positive values ​​of the measuring points and do not require transformation; the dashed arrows represent the actual negative values ​​of the measuring points and require transformation using the above-mentioned roll angle transformation formula; the solid bold arrows represent the positions and sizes of the corresponding positive values ​​calculated using the roll angle transformation formula.

[0124] (1) Measuring point 1: (the abnormal body is located on the positive axis of the X and Z components)

[0125] As shown in FIG9 , the low-resistance anomaly is located on the positive half-axes of the X and Z components, the secondary field induced electromotive force curves are all positive, and the changed roll angle γ′ = the actual roll angle γ.

[0126] (2) Measuring point 2: (the anomaly is located on the negative half axis of the X component and the positive half axis of the Z component)

[0127] The anomaly is located on the negative X-component axis and the positive Z-component axis. The corresponding secondary field original induced electromotive force curve is shown in Figure 10. At this time, the X-component measurement signal is negative, and the roll angle γ = -30°. According to the roll angle conversion formula, the transformed roll angle γ' = -30° + 180° = 150°. The Z-component measurement signal is positive, so no conversion is required. The expanded roll angle after conversion is shown in Figure 11.

[0128] (3) Measuring point three: (the anomaly is located on the negative half axis of the X component and the negative half axis of the Z component)

[0129] When the anomaly is located on the negative half-axis of the X and Z components, the corresponding original induced electromotive force curve of the secondary field is shown in Figure 12. At this time, the measurement signals of the X and Z components are both negative. At this time, the roll angle γ = -30°. According to the roll angle transformation formula, the X component roll angle γ' = 60°-180° = -120°, and the Y component roll angle γ' = -30° + 180° = 150°. The expanded diagram of the transformed roll angle is shown in Figure 13.

[0130] (4) Measurement point 4: (the anomaly is located on the positive half axis of the X component and the negative half axis of the Z component)

[0131] The anomaly is located on the positive half axis of the X component and the negative half axis of the Z component. The corresponding original induced electromotive force curve of the secondary field is shown in Figure 14. At this time, the X component measurement signal is positive and no transformation is required; the Z component measurement signal is negative, and the roll angle γ is -30°. According to the roll angle transformation formula, the Z component roll angle γ' is transformed into -30° + 180° = 150°. The expanded diagram of the transformed roll angle is shown in Figure 15.

[0132] (5) Measuring point 5: (the anomaly is located on the negative half axis of the X component and the positive half axis of the Z component)

[0133] The anomaly is located on the negative half axis of the X component and the positive half axis of the Z component. The corresponding original induced electromotive force curve of the secondary field is shown in Figure 16. At this time, the Z component measurement signal is positive and no transformation is required. The X component measurement signal is negative, and the roll angle γ is 120°. According to the roll angle transformation formula, the transformed X component roll angle γ' is -150° + 180° = 30°. The expanded diagram of the transformed roll angle is shown in Figure 17.

[0134] It should be noted that any of the aforementioned measuring points is interpreted as measuring point information at a certain depth within the borehole (this is done for each measuring point). Based on this, a three-dimensional rectangular coordinate system is established. All measuring points are grouped together at a fixed footage, resulting in the three-dimensional spatial distribution diagram shown in Figure 18: In this coordinate system, the X-axis (horizontal axis) represents the transformed roll angle, the Y-axis (vertical axis) represents the hole depth or actual footage, and the Z-axis (vertical axis) represents the induced electromotive force. Through three-dimensional interpolation calculations, the three-dimensional electromotive force data after the borehole is expanded in terms of roll angle can be obtained.

[0135] Furthermore, after obtaining the three-dimensional electromotive force data, two-dimensional resistivity profile data of all the above-mentioned measuring points are obtained by a known resistivity calculation method, such as a late resistivity calculation formula or other methods. Then, a three-dimensional resistivity data volume centered on the borehole is obtained by three-dimensional interpolation calculation. Specifically, step S42: locating the orientation and distance of the abnormal body based on the three-dimensional electromotive force data includes:

[0136] Using known resistivity calculation methods, the two-dimensional and three-dimensional spatial distribution of resistivity at all measuring points is obtained, and a three-dimensional resistivity data volume centered on the borehole is calculated;

[0137] Extracting a two-dimensional resistivity value profile from the three-dimensional resistivity data volume according to an arbitrary roll angle;

[0138] Based on the two-dimensional resistivity value profile, the geological conditions at any specified orientation and any specified distance of the borehole to be tested are determined.

[0139] As shown in Figures 19 and 20, two-dimensional slice images were extracted at roll angles of -150° and 30°, respectively, reflecting the geological conditions on the lower left and upper right sides of the borehole.

[0140] It should be noted that this embodiment extracts a two-dimensional resistivity profile at an arbitrary roll angle. The roll angle represents the actual borehole orientation, the X-axis (horizontal axis) represents the measurement point-hole depth information, and the Y-axis (vertical axis) represents the measured induced electromotive force. This allows accurate positioning of anomalies around the borehole.

[0141] It should be noted that for anomalies of the same size, the larger the induced electromotive force, the closer the anomaly is to the detection device, and the smaller the corresponding late resistivity calculated value will be; the smaller the induced electromotive force, the farther the anomaly is from the detection device, and the larger the corresponding late resistivity calculated value will be. The distance from the anomaly to the detection device can be expressed by the late resistivity calculation formula, where the late resistivity calculation formula is:

[0142] Where: is the induced electromotive force value, μ0 is the magnetic permeability in vacuum, t is the propagation time, and M is the transmitted magnetic moment. It can be seen that the late resistivity value is inversely proportional to the induced electromotive force value.

[0143] In addition, as shown in FIG17 , the second embodiment of the present invention further provides a drilling transient electromagnetic method three-dimensional expansion processing system, the system comprising:

[0144] An acquisition module 10 is used to acquire measurement information of each measuring point in the borehole to be measured, wherein the measurement information includes secondary field induced electromotive force and roll angle;

[0145] An expansion diagram construction module 20 is used to establish an expansion diagram for each measuring point, using the roll angle as the horizontal coordinate and the secondary field induced electromotive force as the vertical coordinate;

[0146] The electromotive force conversion module 30 is used to convert the electromotive force signal into a positive response according to the roll angle when there is a negative electromotive force signal in the development diagram, so as to obtain measurement conversion information of each measuring point.

[0147] In this embodiment, the negative electromotive force signal is converted into a positive electromotive force signal, which is combined with the originally positive electromotive force signal to determine the orientation of the abnormal body and the distance from the detection device. By expanding the borehole in a roll angle manner, the problem of processing the negative induced electromotive force response detected by the borehole transient electromagnetic method is fundamentally solved, and the negative electromotive force signal can be fully and effectively utilized.

[0148] In one embodiment, the acquisition module 10 is specifically configured to: perform point measurement according to a set step distance to obtain measurement information of each measuring point during the process of sending the transient electromagnetic detection device into and / or out of the borehole to be measured by using a push rod.

[0149] In one embodiment, the acquisition module 10 is further specifically configured to: when the transient electromagnetic detection device is pushed to a certain measuring point by the pushing rod, rotate the transient electromagnetic detection device to measure the lateral information of the borehole at the measuring point.

[0150] In one embodiment, the system further includes a calibration module, wherein the calibration module includes:

[0151] A first coordinate system establishing unit is used to establish a first coordinate system with a roll angle γ of 0°, a right side of 90°, a left side of -90°, a vertical upward direction of the transient electromagnetic detection device of 0°, and a vertical downward direction of +-180°;

[0152] A setting unit is used to set the first receiving coil to be perpendicular to the axial direction of the transient electromagnetic detection device along the horizontal plane and to the right as the positive direction of the X axis of the first coordinate system, and the second receiving coil to be perpendicular to the horizontal plane and upward as the positive direction of the Z axis of the first coordinate system;

[0153] a measuring unit, configured to place an iron object as a known abnormal object in any quadrant of the first coordinate system, and measure an X-component induced electromotive force and a Z-component induced electromotive force respectively through the first receiving coil and the second receiving coil;

[0154] The calibration unit is used to adjust the direction of the X component and / or the direction of the Z component when the X component induced electromotive force and / or the Z component induced electromotive force do not conform to the quadrant, so that the direction of the induced electromotive force conforms to the quadrant.

[0155] In one embodiment, the electromotive force conversion module 30 is specifically used to:

[0156] When a component electromotive force signal in the expanded diagram has a negative response, the roll angle is transformed to convert the negative electromotive force signal into a positive response, wherein the transformation formula of the roll angle is:

[0157] When 0°<γ<180°, γ'=γ-180°

[0158] When -180°<γ<0°, γ'=180°+γ

[0159] Where: γ represents the measured roll angle, and γ' represents the transformed roll angle.

[0160] In one embodiment, the system further includes a region-by-region interpolation module, specifically configured to:

[0161] The induced electromotive force signal of the positive response is divided into a high voltage region and a low voltage region;

[0162] Interpolation operations are performed on high-voltage areas and low-voltage areas respectively, and multiple measuring points in the corresponding areas are smoothly connected to form a multi-channel curve.

[0163] In one embodiment, the system further includes a positioning module 40 for locating the position and distance of the abnormal body based on the measurement transformation information of all measurement points.

[0164] Specifically, the positioning module 40 includes:

[0165] A three-dimensional data volume forming unit is used to form a three-dimensional electromotive force data centered on the drill hole based on the measurement transformation information of all measuring points;

[0166] The positioning unit is used to locate the position and distance of the abnormal body based on the three-dimensional electromotive force data.

[0167] In one embodiment, the three-dimensional data volume forming unit is specifically configured to perform the following steps:

[0168] Establish a second coordinate system with the X-axis of the first coordinate system being the transformed roll angle γ', the Y-axis being the hole depth or actual footage, and the Z-axis being the induced electromotive force value;

[0169] In the second coordinate system, the measurement transformation information of all the measuring points is combined along the depth direction of the borehole to be measured according to the set spacing to obtain the three-dimensional electromotive force data after the borehole to be measured is expanded in the form of a roll angle.

[0170] In one embodiment, the positioning unit is specifically configured to perform the following steps:

[0171] Using known resistivity calculation methods, the two-dimensional and three-dimensional spatial distribution of resistivity at all measuring points is obtained, and a three-dimensional resistivity data volume centered on the borehole is calculated;

[0172] Extracting a two-dimensional resistivity value profile from the three-dimensional resistivity data volume according to an arbitrarily specified roll angle;

[0173] Based on the two-dimensional resistivity value profile, the geological conditions at any specified orientation and any specified distance of the borehole to be tested are determined.

[0174] It should be noted that, although the spatial posture of the drilling hole is not taken into consideration in this embodiment, spatial positioning can be performed based on information such as the drilling hole inclination, azimuth, and hole depth.

[0175] It should be noted that other embodiments or implementation methods of the drilling transient electromagnetic method three-dimensional expansion processing system of the present invention can refer to the above-mentioned method embodiments, which will not be repeated here.

[0176] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "examples," "specific examples," or "some examples" means that a specific feature, structure, material, or characteristic described in conjunction with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0177] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0178] Although the embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A three-dimensional development processing method of drilling transient electromagnetic method, characterized in that: The method comprises: Collecting measurement information of each measuring point in the borehole to be measured, wherein the measurement information includes secondary field induced electromotive force and roll angle; For each measuring point, an expansion diagram is established with the roll angle as the abscissa and the secondary field induced electromotive force as the ordinate; When there is an electromotive force signal with a negative response in the development diagram, the electromotive force signal is transformed into a positive response according to the transformation formula of the roll angle to obtain measurement transformation information of each measuring point.

2. The drilling transient electromagnetic method three-dimensional development processing method according to claim 1, characterized in that: The collecting of measurement information of each measuring point in the borehole to be measured includes: When the transient electromagnetic detection device is sent into and / or withdrawn from the borehole to be measured by using the push rod, point measurement is performed according to the set step distance to obtain measurement information of each measurement point.

3. The drilling transient electromagnetic method three-dimensional development processing method according to claim 2, characterized in that: The transient electromagnetic detection device is rotatably connected to the push rod, and the method further includes: When the transient electromagnetic detection device is pushed or withdrawn to a certain measuring point position by using the pushing rod, the transient electromagnetic detection device is rotated by a specified angle to measure the lateral information of the borehole at the measuring point position.

4. The drilling transient electromagnetic method three-dimensional development processing method according to claim 1, characterized in that: Before collecting the measurement information of each measuring point in the borehole to be measured, the method further includes: When the roll angle γ is 0°, the right side is 90°, the left side is -90°, the vertical upward direction of the transient electromagnetic detection device is 0°, and the vertical downward direction is +-180°, a first coordinate system is established; Set the first receiving coil along the horizontal plane perpendicular to the axial direction of the transient electromagnetic detection device and the right direction is the positive direction of the X axis of the first coordinate system, and the second receiving coil is perpendicular to the horizontal plane and upwards is the positive direction of the Z axis of the first coordinate system; Placing an iron object as a known abnormal object in any quadrant of the first coordinate system, and measuring the X-component induced electromotive force and the Z-component induced electromotive force respectively through the first receiving coil and the second receiving coil; When the X-component induced electromotive force and / or the Z-component induced electromotive force do not conform to the quadrant, the direction of the X-component and / or the direction of the Z-component are adjusted to make the direction of the induced electromotive force conform to the quadrant.

5. The drilling transient electromagnetic method three-dimensional development processing method according to claim 1, characterized in that: When there is an electromotive force signal with a negative response in the development diagram, the electromotive force signal is transformed into a positive response according to the transformation formula of the roll angle to obtain measurement transformation information of each measuring point, including: When a component electromotive force signal in the development diagram is a negative response, the roll angle is transformed to convert the electromotive force signal with a negative response into a positive response, wherein the transformation formula of the roll angle is: When 0°<γ<180°, γ'=γ-180° When -180°<γ<0°, γ'=180°+γ Where: γ represents the measured roll angle, and γ' represents the transformed roll angle.

6. The drilling transient electromagnetic method three-dimensional development processing method according to claim 5, characterized in that: For processing the induced electromotive force signal of the positive response, the method further includes: The induced electromotive force signal of the positive response is divided into a high voltage region and a low voltage region; Interpolation operations are performed on high-voltage areas and low-voltage areas respectively, and multiple measuring points in the corresponding areas are smoothly connected to form a multi-channel curve.

7. The drilling transient electromagnetic method three-dimensional development processing method according to claim 1, characterized in that: When there is an electromotive force signal with a negative response in the development diagram, the electromotive force signal is converted into a positive response according to the conversion formula of the roll angle, and after obtaining the measurement conversion information of each measuring point, the method further includes: locating the orientation and distance of the abnormal body based on the measurement conversion information of all measuring points, specifically: Based on the measurement transformation information of all measuring points, a three-dimensional electromotive force data centered on the drilling hole is formed; The position and distance of the abnormal body are located based on the three-dimensional electromotive force data.

8. The drilling transient electromagnetic method three-dimensional development processing method according to claim 7, characterized in that: The measurement transformation information based on all the measuring points forms a three-dimensional electromotive force data centered on the drilling hole, including: A second coordinate system is established with the X-axis in the first coordinate system being the transformed roll angle γ', the Y-axis being the hole depth or actual footage, and the Z-axis being the induced electromotive force value; In the second coordinate system, the measurement transformation information of all the measuring points is combined along the depth direction of the borehole to be measured according to the set spacing to obtain the three-dimensional electromotive force data after the borehole to be measured is expanded in the form of a roll angle.

9. The drilling transient electromagnetic method three-dimensional development processing method according to claim 7, characterized in that: The positioning of the position and distance of the abnormal body based on the three-dimensional electromotive force data includes: The three-dimensional electromotive force data are processed by using a known resistivity calculation method to obtain the two-dimensional and three-dimensional spatial distribution of resistivity of all measuring points, and a three-dimensional resistivity data volume centered on the borehole is calculated; Extracting a two-dimensional resistivity value profile from the three-dimensional resistivity data volume according to an arbitrarily specified roll angle; Based on the two-dimensional resistivity value profile, the geological conditions at any specified orientation and any specified distance of the borehole to be tested are determined.

10. A three-dimensional development processing system for drilling transient electromagnetic method, characterized in that: The system comprises: An acquisition module is used to acquire measurement information of each measuring point in the borehole to be measured, wherein the measurement information includes secondary field induced electromotive force and roll angle; The expansion diagram construction module is used to construct a graph for each measuring point, with the roll angle as the horizontal coordinate and the secondary field induced electromotive force as the horizontal coordinate. Vertical axis, establish the expansion diagram; The electromotive force conversion module is used to convert the electromotive force signal into a positive response according to the conversion formula of the rolling angle when there is an electromotive force signal with a negative response in the development diagram, so as to obtain the measurement conversion information of each measuring point.

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