A magnetic guidance combined calibration method for long distance horizontal hole

Abstract

The application discloses a magnetic guidance combined calibration method for long-distance horizontal holes, which comprises the following steps: firstly, a magnetic reference benchmark is set, which is used as a true value basis for drilling trajectory checking; then, trajectory data of wireless drilling measurement is acquired according to a first acquisition frequency; magnetic positioning information of the drilling hole relative to a signal hole is acquired according to a second acquisition frequency, so as to form a double-mode combined measurement mode in parallel with the wireless drilling measurement and the magnetic guidance measurement; then, comparison and analysis are carried out to determine whether there is a system error or a cumulative deviation; if the drilling trajectory has a deviation, the wireless drilling measurement data is corrected according to the magnetic positioning result, and relevant parameters are adjusted in linkage to correct the drilling trajectory. The steps of the application are linked and closed-loop cooperated, and the whole forms an integrated trajectory control process from benchmark layout, double-mode acquisition, sectional comparison, trajectory correction, multiple checking to parameter solidification, which can effectively avoid error superposition and improve the spatial stability and comparison accuracy of the checking benchmark.

Description

Technical Field

[0001] This invention relates to the field of underground engineering drilling construction and borehole trajectory control technology. Specifically, it is a magnetic guidance combined calibration method for long-distance horizontal boreholes. Background Technology

[0002] In the process of advanced geological exploration of tunnels, underground engineering treatment and long-distance horizontal hole construction, the drilling trajectory is usually guided in real time by wireless measurement while drilling technology to achieve control of well inclination angle and azimuth angle.

[0003] However, in construction scenarios involving large borehole lengths, long drilling distances, or situations requiring significant azimuth adjustments due to surface conditions, wireless measurement-while-drilling (MWD) technology is prone to systematic errors and cumulative deviations during long-term continuous drilling, causing the borehole trajectory to gradually deviate from the design trajectory. In projects with high requirements for borehole accuracy and strict requirements for the relative positional relationships of boreholes, it is difficult to maintain the borehole trajectory within an acceptable accuracy range over the long term using only wireless MWD technology.

[0004] To address the aforementioned issues, magnetic guidance or magnetic positioning methods are required in some projects to correct and calibrate the borehole trajectory in the initial section or key control area of ​​the target treatment zone. Magnetic guidance technology can effectively compensate for wireless measurement-while-drilling results by acquiring spatial relationship information between the borehole and a known magnetic source.

[0005] However, existing magnetic guidance technologies mainly focus on the layout of magnetic signal acquisition circuits, construction of magnetic field models, and inversion of single-point relative positions. They emphasize signal acquisition and positioning result output, and still suffer from technical problems such as the instability of long-term drift in single-drilling recursion and the limited anti-interference of pure magnetic single-point drilling, resulting in low accuracy of drilling trajectory control in long-distance horizontal holes. Therefore, there is an urgent need for a magnetic positioning calibration and verification method for long-distance horizontal hole construction to solve the technical problem of low accuracy of drilling trajectory control in long-distance horizontal holes caused by the existing magnetic guidance technology's emphasis on signal acquisition and positioning result output. Summary of the Invention

[0006] Therefore, the technical problem to be solved by the present invention is to provide a magnetic guidance joint calibration method for long-distance horizontal holes. By introducing a joint verification mechanism of magnetic guidance and wireless measurement while drilling during the drilling process, the systematic errors generated by measurement while drilling are calibrated and verified in stages, thereby improving the control accuracy of the drilling trajectory of long-distance horizontal holes.

[0007] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0008] A magnetically guided joint calibration method for long-distance horizontal apertures includes the following steps:

[0009] Step P1: Set up reference signal holes

[0010] Signal holes are set up in the vicinity of the long-distance horizontal hole to be constructed, and magnetic sources are arranged in the signal holes to construct a stable and independent magnetic reference benchmark, which serves as the true value basis for drilling trajectory verification.

[0011] Step P2, Dual-mode joint measurement

[0012] During long-distance horizontal hole drilling, trajectory data of wireless drilling measurement is acquired according to the first acquisition frequency; when drilling reaches the effective range of the magnetic guidance signal, magnetic guidance measurement is started, and magnetic positioning information of the borehole relative to the signal hole is acquired according to the second acquisition frequency, forming a dual-mode joint measurement mode in parallel with wireless drilling measurement and magnetic guidance measurement.

[0013] Step P3, Phased Magnetic Positioning Verification

[0014] The magnetic positioning results are compared and analyzed with the wireless drilling measurement results. Based on the comparison and analysis results, it is determined whether there are systematic errors or cumulative deviations.

[0015] If not, continue with conventional drilling and conduct continuous comparative analysis during the drilling process;

[0016] If so, proceed to the next correction step;

[0017] Step P4: Trajectory Calibration and Parameter Correction

[0018] When the judgment results indicate that the borehole trajectory deviates from the design trajectory or there is a trend of cumulative deviation, the wireless drilling measurement data is corrected based on the magnetic positioning results, and relevant parameters are adjusted in conjunction to correct the borehole trajectory.

[0019] In the above-mentioned magnetic guidance joint calibration method for long-distance horizontal holes, in step P1, the signal hole is arranged directly above the tunnel axis, so that it is distributed in two-dimensional space with the tunnel axis on the tunnel axis profile, in order to simplify the magnetic field calculation model, thereby reducing the impact of orientation adjustment on construction accuracy and improving trajectory verification accuracy.

[0020] In the above-mentioned magnetic guidance joint calibration method for long-distance horizontal holes, in step P1, the signal hole is an oblique straight hole or a near straight hole, so as to reduce the difficulty of drilling trajectory control and compress construction errors, thereby ensuring the spatial position accuracy of the magnetic source built into the signal hole and improving the positioning reliability and comparison effectiveness of the magnetic guidance reference signal.

[0021] In the above-mentioned magnetically guided joint calibration method for long-distance horizontal holes, in step P2, the second acquisition frequency is higher than the first acquisition frequency. Wireless drilling measurement acquires data according to the first acquisition frequency for continuous recursion of the overall trajectory and long-term monitoring. Magnetic positioning information is acquired according to the second acquisition frequency, which is higher than the first acquisition frequency, for fixed-point verification and deviation capture in key sections, thereby forming a dual-mode parallel joint measurement mode of low-frequency continuous recursion and high-frequency fixed-point verification.

[0022] In the above-mentioned magnetic guidance joint calibration method for long-distance horizontal holes, during step P3, a phased composite verification is carried out on the spatial position, inclination angle and azimuth angle of the current borehole trajectory during comparative analysis.

[0023] The specific comparative analysis process of step P3 in the above-mentioned magnetically guided joint calibration method for long-distance horizontal holes is as follows:

[0024] The parameters of the segmented magnetic positioning measurement results and the wireless drilling measurement trajectory are aligned and cross-compared to verify the spatial position, inclination angle and azimuth angle of the current borehole trajectory, and to identify whether there are inherent systematic errors or long-term cumulative deviations in the drilling measurement.

[0025] The specific calibration and correction process in step P4 of the above-mentioned magnetically guided joint calibration method for long-distance horizontal holes is as follows:

[0026] When the trajectory is determined to deviate from the design direction or show a trend of cumulative deviation, the wireless drilling foundation calculation parameters are corrected in reverse based on the magnetic positioning truth value, and related parameters are adjusted in conjunction to achieve zeroing of the measurement base and control of the construction posture, gradually narrowing the offset path and making the drilling trajectory return to the preset main axis.

[0027] The aforementioned magnetically guided joint calibration method for long-distance horizontal holes includes drilling control parameters and horizontal section construction orientation compensation parameters.

[0028] The aforementioned magnetically guided joint calibration method for long-distance horizontal holes involves cyclically executing steps P3 and P4 at preset advance intervals in the area near the signal hole and in the key controlled section. This process, through segmented, multiple, and progressive correction, gradually converges the borehole trajectory to the designed trajectory, thereby reducing the construction risks and trajectory fluctuations caused by a single large-amplitude tilt adjustment.

[0029] In the above-mentioned magnetically guided joint calibration method for long-distance horizontal holes, in step P4, after the borehole trajectory meets the preset spatial accuracy index, the magnetic constraint calibration is exited; the well inclination parameters, azimuth parameters and compensation parameters corrected by magnetic guidance are solidified as reference parameters, which serve as the main control basis for subsequent long-distance horizontal extension sections, so as to realize the early calibration and later use, thereby taking into account both construction accuracy and drilling efficiency.

[0030] The technical solution of the present invention achieves the following beneficial technical effects:

[0031] This invention uses external signal holes, either oblique or nearly straight, arranged separately outside the main horizontal hole as magnetic references. The reference trajectory is simple to form, has small original errors, and is spatially stable. It is independent of the main hole measurement, avoids the superposition of errors from the same source, significantly improves the reliability of the true value of trajectory verification, and reduces the calculation error caused by long-distance comparison.

[0032] This application employs a dual-mode joint measurement method of "low-frequency continuous monitoring while drilling and high-frequency magnetic measurement point verification." Low-frequency wireless measurement while drilling enables continuous and stable monitoring of the main trajectory throughout the entire process, ensuring efficiency and data continuity during long-distance drilling. Simultaneously, within the effective range of the magnetic signal, higher-frequency magnetic guidance measurement is used for point verification, quickly capturing minor local deviations and achieving the effect of suppressing error accumulation in advance without reducing drilling speed. Based on this, multiple verifications and gradual small-amplitude corrections ensure smooth trajectory convergence, reducing construction risks such as borehole wall disturbance and stuck drill caused by large-scale skew adjustments. Finally, the corrected parameters are solidified and reused, effectively suppressing secondary drift during subsequent long-distance drilling and further improving the accuracy of end-point calibration. Attached Figure Description

[0033] Figure 1 This is a schematic flowchart of a magnetically guided joint calibration method for long-distance horizontal holes according to the present invention.

[0034] Figure 2 This is a schematic diagram of the signal hole arrangement in a magnetically guided joint calibration method for long-distance horizontal holes according to the present invention.

[0035] Figure 3 This is an engineering construction case diagram of a magnetically guided joint calibration method for long-distance horizontal holes according to the present invention. Detailed Implementation

[0036] This embodiment discloses a magnetically guided joint calibration method for long-distance horizontal holes, such as... Figures 1 to 3 As shown, it includes the following steps:

[0037] Step P1: Set up reference signal holes

[0038] Signal holes are installed directly above the tunnel axis, constructed using either inclined or near-straight holes. These signal holes and the tunnel axis form a two-dimensional spatial relationship in the axial section, reducing the difficulty of magnetic field calculation and construction errors caused by azimuth adjustments. A fixed magnetic source is pre-installed inside the signal holes to construct an independent, low-error, and spatially reliable external magnetic reference benchmark, avoiding the superposition of errors from the main borehole. On-site geomagnetic calibration is completed before construction to standardize magnetic declination and inclination, achieving coordinate system alignment.

[0039] Step P2, Dual-mode joint measurement

[0040] During continuous directional drilling of long-distance horizontal boreholes, wireless measurement while drilling (MWD) is conducted at a predetermined first acquisition frequency to continuously acquire borehole inclination, azimuth, spatial coordinates, and attitude parameters. Through recursive calculations while drilling, a continuous borehole trajectory is generated in real time for long-term, stable, and uninterrupted dynamic monitoring of the entire horizontal borehole, ensuring normal drilling progress and data continuity.

[0041] When the drill bit enters the effective range of the magnetic signal generated by the magnetic source of the signal hole, the magnetic guidance high-precision positioning measurement mode is started simultaneously, and the spatial magnetic positioning information of the drill bit relative to the upper magnetic source of the signal hole is periodically acquired at a second encrypted acquisition frequency higher than the first acquisition frequency.

[0042] Among them, wireless measurement while drilling has a large sampling interval and low frequency, focusing on low-frequency continuous recursion and overall trajectory extension; magnetic guidance measurement has a small sampling interval and high frequency, focusing on high-frequency densification of measurement points, local fixed-point verification, and capture of minute deviations.

[0043] The two methods are synchronized, operate synchronously, and complement each other, forming a dual-mode parallel joint measurement system that combines low-frequency continuous trajectory tracking with high-frequency fixed-point deviation detection. This avoids the efficiency reduction and cost increase caused by full-process high-frequency magnetic measurement, while also compensating for the shortcomings of single measurement-while-drilling (MSW) which easily accumulates drift and has a lag in deviation detection. It enables controllable long-distance drilling trajectory and traceable errors from the data source.

[0044] Compared to existing single wireless drilling or single magnetic-guided directional drilling technologies, this invention constructs an external magnetic reference benchmark by independently deploying inclined or near-straight reference signal holes outside the main borehole. This effectively avoids the superposition of errors from the same source and improves the spatial stability and comparison accuracy of the verification benchmark. At the same time, it adopts a dual-mode sparse-dense joint measurement mode of low-frequency continuous monitoring while drilling and high-frequency magnetic measurement point verification. This not only ensures the continuity and construction efficiency of long-distance drilling, but also captures small deviations in key sections in a timely manner, achieving a balance between accuracy and efficiency.

[0045] Step P3, Phased Magnetic Positioning Verification

[0046] During drilling operations, periodic magnetic positioning checks are conducted at preset advance intervals. The measured magnetic positioning reference data is then aligned and the borehole trajectory data obtained from wireless drilling calculations are normalized.

[0047] The real-time spatial location, inclination angle, and azimuth angle of the borehole were compared and verified separately to identify two types of error sources.

[0048] One type is the inherent systematic error introduced by the measurement while drilling equipment itself;

[0049] Another type is the trajectory drift and cumulative deviation formed by long-distance recursive calculation.

[0050] The judgment rules are as follows:

[0051] If the comparison results are within the preset accuracy threshold range and no obvious systematic error or cumulative deviation is detected, the original drilling parameters shall be maintained, conventional directional drilling shall continue, and periodic comparison and verification shall be continuously carried out in subsequent drilling.

[0052] If the comparison result exceeds the preset accuracy threshold, or if obvious systematic errors are identified and the deviation shows a continuous accumulation trend, it is determined that the trajectory is at risk of deviation, and the next step of trajectory calibration and parameter correction process is initiated.

[0053] Step P4: Trajectory Calibration and Parameter Correction

[0054] When the judgment result indicates that the borehole trajectory deviates from the design trajectory or has a tendency to accumulate deviation, the wireless drilling measurement data is corrected based on the magnetic positioning results, and relevant parameters are adjusted accordingly to correct the borehole trajectory. Specifically, when it is determined that the trajectory deviates from the design direction or shows a tendency to accumulate deviation, the wireless drilling foundation measurement parameters are reversed based on the magnetic positioning truth value, and relevant parameters are adjusted accordingly to achieve zeroing of the measurement baseline and control of the construction posture, gradually narrowing the offset path and bringing the borehole trajectory back to the preset main axis.

[0055] Furthermore, in the areas surrounding the signal borehole, trajectory-sensitive sections, and key controlled construction sections, P3 comparison and judgment and P4 parameter correction are cyclically performed at fixed advance intervals. Through segmented, multiple, and minor corrections, the borehole trajectory gradually and smoothly converges to the designed trajectory, reducing construction risks and improving trajectory stability. This invention, by segmenting and comparing the borehole spatial position, inclination angle, and azimuth angle, can distinguish between inherent systematic errors during drilling and long-distance recursive cumulative drift errors, achieving targeted correction and reducing directional margin consumption. Combined with multiple verifications and a progressive closed-loop small-amplitude correction method, the borehole trajectory converges smoothly, reducing trajectory bending, borehole wall disturbance, and stuck drill risks caused by large-scale inclination adjustments, resulting in higher borehole quality. After the trajectory meets the accuracy requirements, the correction parameters are solidified and applied to subsequent horizontal drilling, continuously suppressing secondary drift in long-distance drilling measurements and significantly improving the target accuracy of ultra-long-distance boreholes.

[0056] Furthermore, once the borehole trajectory meets the preset spatial accuracy indicators, the high-frequency magnetic constraint calibration mode is exited. The well inclination parameters, azimuth parameters, and compensation parameters after magnetic reference correction are uniformly solidified as reference parameters, serving as the main control basis for subsequent long-distance horizontal extension sections. Relying on the solidified parameters to suppress subsequent drift while drilling and reduce the number of frequent magnetic measurements, this ensures both long-distance drilling accuracy and effectively improves overall drilling efficiency.

[0057] The above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of the claims of this patent application.

Claims

1. A magnetically guided joint calibration method for long-distance horizontal apertures, characterized in that, Includes the following steps: Step P1: Set up reference signal holes Signal holes are set up in the vicinity of the long-distance horizontal hole to be constructed, and magnetic sources are arranged in the signal holes to construct a stable and independent magnetic reference benchmark, which serves as the true value basis for drilling trajectory verification. Step P2, Dual-mode joint measurement During long-distance horizontal hole drilling, trajectory data of wireless drilling measurement is acquired according to the first acquisition frequency; when drilling reaches the effective range of the magnetic guidance signal, magnetic guidance measurement is started, and magnetic positioning information of the borehole relative to the signal hole is acquired according to the second acquisition frequency, forming a dual-mode joint measurement mode in parallel with wireless drilling measurement and magnetic guidance measurement. Step P3, Phased Magnetic Positioning Verification The magnetic positioning results are compared and analyzed with the wireless drilling measurement results. Based on the comparison and analysis results, it is determined whether there are systematic errors or cumulative deviations. If not, continue with conventional drilling and conduct continuous comparative analysis during the drilling process; If so, proceed to the next correction step; Step P4: Trajectory Calibration and Parameter Correction When the judgment results indicate that the borehole trajectory deviates from the design trajectory or there is a trend of cumulative deviation, the wireless drilling measurement data is corrected based on the magnetic positioning results, and relevant parameters are adjusted in conjunction to correct the borehole trajectory.

2. The magnetically guided joint calibration method for long-distance horizontal holes according to claim 1, characterized in that, In step P1, the signal holes are positioned directly above the tunnel axis, so that they are distributed in a two-dimensional space on the tunnel axis profile, thereby simplifying the magnetic field calculation model, reducing the impact of orientation adjustment on construction accuracy, and improving trajectory verification accuracy.

3. The magnetically guided joint calibration method for long-distance horizontal holes according to claim 2, characterized in that, In step P1, the signal hole is an oblique straight hole or a near straight hole to reduce the difficulty of drilling trajectory control and compress construction errors, thereby ensuring the spatial position accuracy of the magnetic source built into the signal hole and improving the positioning reliability and comparison effectiveness of the magnetic guidance reference signal.

4. A magnetically guided joint calibration method for long-distance horizontal holes according to any one of claims 1-3, characterized in that, In step P2, the second acquisition frequency is higher than the first acquisition frequency. Wireless drilling measurement acquires data according to the first acquisition frequency for continuous recursion of the overall trajectory and long-term monitoring. Magnetic positioning information is acquired according to the second acquisition frequency, which is higher than the first acquisition frequency, for fixed-point verification and deviation capture in key sections, thereby forming a dual-mode parallel joint measurement mode of low-frequency continuous recursion and high-frequency fixed-point verification.

5. A magnetically guided joint calibration method for long-distance horizontal holes according to any one of claims 1-3, characterized in that, In step P3, during the comparative analysis, a phased composite verification is carried out on the spatial position, inclination angle, and azimuth angle of the current borehole trajectory.

6. The magnetically guided joint calibration method for long-distance horizontal holes according to claim 5, characterized in that, The specific comparative analysis process in step P3 is as follows: The parameters of the segmented magnetic positioning measurement results and the wireless drilling measurement trajectory are aligned and cross-compared to verify the spatial position, inclination angle and azimuth angle of the current borehole trajectory, and to identify whether there are inherent systematic errors or long-term cumulative deviations in the drilling measurement.

7. A magnetically guided joint calibration method for long-distance horizontal holes according to any one of claims 1-3, characterized in that, The specific calibration and correction process in step P4 is as follows: When the trajectory is determined to deviate from the design direction or show a trend of cumulative deviation, the wireless drilling foundation calculation parameters are corrected in reverse based on the magnetic positioning truth value, and related parameters are adjusted in conjunction to achieve zeroing of the measurement base and control of the construction posture, gradually narrowing the offset path and making the drilling trajectory return to the preset main axis.

8. A magnetically guided joint calibration method for long-distance horizontal holes according to claim 7, characterized in that, The relevant parameters include drilling control parameters and horizontal section construction orientation compensation parameters.

9. A magnetically guided joint calibration method for long-distance horizontal holes according to any one of claims 1-3, characterized in that, In the area near the signal hole and in the key controlled section, steps P3 and P4 are executed cyclically according to the preset advance interval. By segmenting, repeating, and gradually correcting the deviation, the drilling trajectory is gradually converged to the design trajectory, thereby reducing the construction risks and trajectory fluctuations caused by a single large-scale deviation adjustment.

10. A magnetically guided joint calibration method for long-distance horizontal holes according to any one of claims 1-3, characterized in that, In step P4, after the borehole trajectory meets the preset spatial accuracy index, the magnetic constraint calibration is exited; the well inclination parameters, azimuth parameters and compensation parameters corrected by magnetic guidance are solidified as benchmark parameters, which serve as the main control basis for subsequent long-distance horizontal extension sections, so as to achieve early calibration and later use, thereby taking into account both construction accuracy and drilling efficiency.

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