A method and system for borehole cross-well seismic ahead-of-drill detection

Abstract

This invention discloses a method and system for borehole-to-bore seismic advance detection. A trajectory measuring instrument is used to measure the corresponding borehole trajectory in a completed borehole A, and the borehole coordinates x(L) at different depths L are calculated. Multiple tandem seismic sensors are deployed at equal intervals in borehole A, and seismic data is acquired and analyzed simultaneously with the drilling process using a drilling-while-drilling mode. This eliminates the need for additional steps and time, solving the technical problem of low timeliness in existing geological exploration methods ahead of tunneling. By deploying seismic sensors in the completed borehole to receive seismic wave data in real time, and using a data acquisition and processing system for data analysis, geological information between boreholes can be obtained as early as possible, avoiding information loss and deviation due to delays. This enables accurate analysis and prediction of the stratigraphic structure and stress anomalies between boreholes, solving the technical problem of low accuracy in existing geological exploration methods ahead of tunneling.

Description

Technical Field

[0001] This invention belongs to the field of geophysical exploration technology and relates to seismic advance detection methods, specifically a borehole-based inter-hole seismic advance detection method and system. Background Technology

[0002] In mining operations, understanding the geological conditions ahead is crucial for ensuring mine safety and developing effective mining plans. Traditional geological exploration methods suffer from high costs, long processing times, and the inability to obtain real-time underground information, necessitating a more efficient and accurate method to meet practical needs. Summary of the Invention

[0003] To address the shortcomings of existing technologies, the present invention aims to provide a method and system for borehole-to-bore seismic advance detection, thereby solving the technical problems of low timeliness and accuracy of existing geological exploration methods ahead of tunneling.

[0004] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0005] A method for borehole-to-bore seismic advance detection, the method specifically includes the following steps:

[0006] Step 1: Use a trajectory measuring instrument to measure the corresponding borehole trajectory in the completed borehole A, and use the borehole trajectory to calculate the borehole coordinates x(L) corresponding to different borehole depths L.

[0007] Step 2: Install multiple seismic sensors in series at equal intervals in borehole A, and connect the seismic sensor located at the borehole opening to the external data acquisition system.

[0008] The depth of the seismic sensor in borehole A is denoted as L. i , where i is the serial number of the earthquake sensor;

[0009] Step 3: Seal borehole A;

[0010] Step four: Interpolate the borehole coordinates x(L) corresponding to different borehole depths L to obtain the coordinates x of each seismic sensor. i ;

[0011] Step 5: Set the sampling rate f, gain, and data storage location of the data acquisition system, and enable real-time acquisition;

[0012] Step 6: Save the collected data F over a period of time. i (t), for a set of real-time collected data F i (t) is preprocessed to obtain the cross-correlation travel time ΔT ij and the corresponding cross-correlation coefficient c il;

[0013] Step 7: Calculate the data quality evaluation coefficient σ according to the following formula, and determine whether σ≥θ is satisfied. If yes, proceed to step 8; otherwise, return to step 6.

[0014]

[0015] in:

[0016] N represents the number of seismic sensors.

[0017] θ is a given threshold;

[0018] Step 8: Employ a method based on double-difference inversion and cross-correlation travel time ΔT. ij The inversion yields the current time τ and the location S of the drill bit source. τ And the seismic wave velocity distribution V on the curved surface formed by the drill bit and borehole A τ (x);

[0019] Step nine, employing relative transmission coefficient tomography and cross-correlation coefficient c ij Seismic wave velocity distribution V τ (x) and the location S of the drill bit vibration source τ The transmission coefficient distribution T on the curved surface formed by the drill bit and borehole A is obtained. τ (x);

[0020] Step 10: Obtain the velocity distribution V′(x) and transmission coefficient distribution T′(x) according to the following formulas;

[0021]

[0022] Step 11: Set the current drill bit vibration source position S τ The velocity distribution V′(x) and transmission coefficient distribution T′(x) are transmitted to external display software in real time.

[0023] Step 12: Return to Step 6 until hole B is completed;

[0024] Step thirteen, utilize all obtained ΔT ij and S τ Perform tomographic inversion to obtain the final velocity distribution V(x);

[0025] Step fourteen, utilize all obtained c ij and S τ Perform tomographic inversion to obtain the final relative transmittance coefficient distribution T(x);

[0026] Step 15: Calculate the average value of V(x). The deviation of V(x) is calculated using formula (4). And The region is designated as a stress anomaly zone. A region is considered a positive anomaly, and vice versa;

[0027]

[0028] Step 16: Determine possible abnormal geological structures based on the relative transmission coefficient distribution T(x).

[0029] In step six, a set of real-time collected data F is processed. i (t) is preprocessed to obtain the cross-correlation travel time ΔT ij and the corresponding cross-correlation coefficient c ij ;

[0030] Step 6.1, process the collected data F i (t) is subjected to bandpass filtering to obtain the filtered acquired data F′ i (t);

[0031] Step 6.2, process the filtered acquired data F′ i (t) Perform a Fourier transform to obtain the frequency domain acquisition data.

[0032] Step 6.3, process the collected data using the following formula. Perform pairwise cross-correlation interference to obtain cross-correlation data.

[0033]

[0034] in:

[0035] i and j both represent the serial numbers of the seismic sensors, i≠j;

[0036] "*" indicates complex conjugation;

[0037] ε is a positive number;

[0038] Step 6.4, cross-correlation data Performing an inverse Fourier transform yields the cross-correlation data F in the time domain. i ′ j (t), in each cross-correlation data F i ′ j Pick the cross-correlation travel time ΔT on (t) ij and the corresponding cross-correlation coefficient c ij .

[0039] In step five, the sampling rate f of the data acquisition system is in the range of 1000Hz to 4000Hz.

[0040] In step two, the spacing between the seismic sensors is 2 to 5 meters; the number of seismic sensors is at least 12, and the bandwidth of the seismic sensors is 5 Hz to 500 Hz.

[0041] In step three, foam adhesive is used to seal borehole A.

[0042] A borehole-to-hole seismic advance detection system, based on the aforementioned borehole-to-hole seismic advance detection method, includes a trajectory measurement module, a data acquisition module, a data processing module, a CT tomography inversion module, a stress anomaly analysis module, and a structural anomaly analysis module.

[0043] The trajectory measurement module is used to measure the corresponding borehole trajectory in the completed borehole A using a trajectory measuring instrument, and to calculate the borehole coordinates x(L) at different borehole depths L using the borehole trajectory. It also interpolates the borehole coordinates x(L) at different borehole depths L to obtain the coordinates x of each seismic sensor. i ;

[0044] The data acquisition module is used to deploy multiple series-connected seismic sensors at equal intervals in borehole A, connect the seismic sensor located at the borehole opening to the external data acquisition system, and set the sampling rate f, gain and data storage location of the data acquisition system to enable real-time acquisition.

[0045] The data processing module is used to store the collected data F over a period of time. i (t), for a set of real-time collected data F i (t) is preprocessed to obtain the cross-correlation travel time ΔT ij and the corresponding cross-correlation coefficient c ij The method based on double-difference inversion and cross-correlation travel time ΔT is adopted. ij The inversion yields the current time τ and the location S of the drill bit source. τ And the seismic wave velocity distribution V on the curved surface formed by the drill bit and borehole A τ (x); relative transmission coefficient tomography and cross-correlation coefficient c were employed. ij Seismic wave velocity distribution V τ (x) and the location S of the drill bit vibration source τ The transmission coefficient distribution T on the curved surface formed by the drill bit and borehole A is obtained. τ (x); obtain the velocity distribution and transmission coefficient distribution T ′ (x);

[0046] The CT tomography inversion module is used to utilize all obtained ΔT ij and S τPerform tomographic inversion to obtain the final velocity distribution V(x); use all obtained c ij and S τ Perform tomographic inversion to obtain the final relative transmittance coefficient distribution T(x);

[0047] The stress anomaly analysis module is used to calculate the average value of V(x). and deviation value And The region is designated as a stress anomaly zone. A region is considered a positive anomaly, and vice versa;

[0048] The aforementioned structural anomaly analysis module is used to determine possible abnormal geological structures based on the relative transmission coefficient distribution T(x).

[0049] Compared with the prior art, the beneficial technical effects of this invention are:

[0050] (I) The present invention adopts the drilling-while-drilling mode, which performs seismic data acquisition and analysis simultaneously with the drilling process, without the need for additional work steps and time, thus solving the technical problem of low timeliness of existing geological exploration methods in front of the tunnel.

[0051] (II) In this invention, seismic sensors are installed in the completed boreholes to receive seismic wave data in real time. Data acquisition and processing systems are used to analyze the data, which can obtain geological information between boreholes as early as possible, avoid information loss and deviation due to delay, and achieve accurate analysis and prediction of the stratigraphic structure and stress anomalies between boreholes. This solves the technical problem of low accuracy of existing geological exploration methods in front of tunneling.

[0052] (III) The present invention can help mine managers assess mine stability and disaster risks by obtaining earthquake early detection results in a timely manner, and take necessary safety measures in advance, thus effectively avoiding some safety hazards. Attached Figure Description

[0053] Figure 1 A schematic diagram of the observation system layout and wavefield propagation path;

[0054] Figure 2 This is a velocity distribution diagram;

[0055] Figure 3 This is a graph showing the transmission coefficient distribution.

[0056] The specific content of the present invention will be further explained in detail below with reference to the embodiments. Detailed Implementation

[0057] It should be noted that, unless otherwise specified, all components in this invention are those known in the art.

[0058] The following are specific embodiments of the present invention. It should be noted that the present invention is not limited to the following specific embodiments. All equivalent modifications made based on the technical solutions of this application fall within the protection scope of the present invention.

[0059] This invention provides a method for borehole-to-bore seismic advance detection, which specifically includes the following steps:

[0060] Step 1: Use a trajectory measuring instrument to measure the corresponding borehole trajectory in the completed borehole A, and use the borehole trajectory to calculate the borehole coordinates x(L) corresponding to different borehole depths L.

[0061] Step 2: Install multiple seismic sensors in series at equal intervals in borehole A, and connect the seismic sensor located at the borehole opening to the external data acquisition system.

[0062] The depth of the seismic sensor in borehole A is denoted as L. i , where i is the serial number of the earthquake sensor;

[0063] Step 3: Seal borehole A;

[0064] Step four: Interpolate the borehole coordinates x(L) corresponding to different borehole depths L to obtain the coordinates x of each seismic sensor. i ;

[0065] Step 5: Set the sampling rate f, gain, and data storage location of the data acquisition system, and enable real-time acquisition;

[0066] Step 6: Save the collected data F over a period of time. i (t), for a set of real-time collected data F i (t) is preprocessed to obtain the cross-correlation travel time ΔT ij and the corresponding cross-correlation coefficient c il ;

[0067] Step 7: Calculate the data quality evaluation coefficient σ according to the following formula, and determine whether σ≥θ is satisfied. If yes, proceed to step 8; otherwise, return to step 6.

[0068]

[0069] in:

[0070] N represents the number of seismic sensors.

[0071] θ is a given threshold;

[0072] Step 8: Employ a method based on double-difference inversion and cross-correlation travel time ΔT. ij The inversion yields the current time τ and the location S of the drill bit source.τ And the seismic wave velocity distribution V on the curved surface formed by the drill bit and borehole A τ (x);

[0073] Step nine, employing relative transmission coefficient tomography and cross-correlation coefficient c ij Seismic wave velocity distribution V τ (x) and the location S of the drill bit vibration source τ The transmission coefficient distribution T on the curved surface formed by the drill bit and borehole A is obtained. τ (x);

[0074] Step 10: Obtain the velocity distribution V′(x) and transmission coefficient distribution T′(x) according to the following formulas;

[0075]

[0076] Step 11: Set the current drill bit vibration source position S τ The velocity distribution V′(x) and transmission coefficient distribution T′(x) are transmitted to external display software in real time.

[0077] Step 12: Return to Step 6 until hole B is completed;

[0078] Step thirteen, utilize all obtained ΔT ij and S τ Perform tomographic inversion to obtain the final velocity distribution V(x);

[0079] Step fourteen, utilize all obtained c ij and S τ Perform tomographic inversion to obtain the final relative transmittance coefficient distribution T(x);

[0080] Step 15: Calculate the average value of V(x). The deviation of V(x) is calculated using formula (4). And The region is designated as a stress anomaly zone. A region is considered a positive anomaly, and vice versa;

[0081]

[0082] Step 16: Determine possible abnormal geological structures based on the relative transmission coefficient distribution T(x).

[0083] In the above technical solution, the drilling-while-drilling mode is adopted, and seismic data acquisition and analysis are carried out simultaneously with the drilling process. No additional work steps and time are required, which solves the technical problem of low timeliness of existing geological exploration methods in front of the tunnel.

[0084] See Figure 1By deploying seismic sensors in the completed boreholes to receive seismic wave data in real time and using a data acquisition and processing system for data analysis, geological information between boreholes can be obtained as early as possible, avoiding information loss and deviation due to delays. This enables accurate analysis and prediction of the stratigraphic structure and stress anomalies between boreholes, solving the technical problem of low accuracy in existing geological exploration methods ahead of tunneling.

[0085] like Figure 2 and Figure 3 As shown, the final velocity distribution V(x) and relative transmission coefficient distribution T(x) are obtained. By obtaining the seismic advance detection results in a timely manner, mine managers can assess the stability of the mine and the risk of disasters, take necessary safety measures in advance, and effectively avoid some safety hazards.

[0086] Specifically, in step six, a set of real-time collected data F... i (t) is preprocessed to obtain the cross-correlation travel time ΔT ij and the corresponding cross-correlation coefficient c ij ;

[0087] Step 6.1, process the collected data F i (t) is subjected to bandpass filtering to obtain the filtered acquired data F′ i (t);

[0088] Step 6.2, process the filtered acquired data F′ i (t) Perform a Fourier transform to obtain the frequency domain acquisition data.

[0089] Step 6.3, process the collected data using the following formula. Perform pairwise cross-correlation interference to obtain cross-correlation data.

[0090]

[0091] in:

[0092] i and j both represent the serial numbers of the seismic sensors, i≠j;

[0093] "*" indicates complex conjugation;

[0094] ε is a positive number;

[0095] Step 6.4, cross-correlation data Performing an inverse Fourier transform yields the cross-correlation data F in the time domain. i ′ j (t), in each cross-correlation data F i ′ jPick the cross-correlation travel time ΔT on (t) ij and the corresponding cross-correlation coefficient c ij .

[0096] In the above scheme, ε is a sufficiently small positive number, which can generally be taken as... 1 / 40 of the average value ensures that formula (1) is stable.

[0097] Specifically, in step five, the sampling rate f of the data acquisition system ranges from 1000Hz to 4000Hz.

[0098] Specifically, in step two, the spacing between the seismic sensors is 2 to 5 meters; the number of seismic sensors is at least 12, and the bandwidth of the seismic sensors is 5 Hz to 500 Hz.

[0099] Specifically, in step three, foam adhesive is used to seal borehole A to effectively prevent sound wave interference.

[0100] This invention also provides a borehole-to-hole seismic advance detection system based on the borehole-to-hole seismic advance detection method, including a trajectory measurement module, a data acquisition module, a data processing module, a CT tomography inversion module, a stress anomaly analysis module, and a structural anomaly analysis module.

[0101] The trajectory measurement module is used to measure the corresponding borehole trajectory in the completed borehole A using a trajectory measuring instrument. Using this borehole trajectory, it calculates the borehole coordinates x(L) at different borehole depths L, and interpolates the borehole coordinates x(L) at different borehole depths L to obtain the coordinates x of each seismic sensor. i ;

[0102] The data acquisition module is used to deploy multiple series-connected seismic sensors at equal intervals in borehole A, connect the seismic sensors located at the borehole opening to the external data acquisition system, and set the sampling rate f, gain, and data storage location of the data acquisition system to enable real-time acquisition.

[0103] The data processing module is used to save the collected data F over a period of time. i (t), for a set of real-time collected data F i (t) is preprocessed to obtain the cross-correlation travel time ΔT ij and the corresponding cross-correlation coefficient c il The method based on double-difference inversion and cross-correlation travel time ΔT is adopted. ij The inversion yields the current time τ and the location S of the drill bit source. τ And the seismic wave velocity distribution V on the curved surface formed by the drill bit and borehole A τ (x); relative transmission coefficient tomography and cross-correlation coefficient c were employed. ijSeismic wave velocity distribution V τ (x) and the location S of the drill bit vibration source τ The transmission coefficient distribution T on the curved surface formed by the drill bit and borehole A is obtained. τ (x); obtain the velocity distribution V ′ (x) and transmission coefficient distribution T ′ (x);

[0104] The CT tomography inversion module is used to utilize all obtained ΔT ij and S τ Perform tomographic inversion to obtain the final velocity distribution V(x); use all obtained c ij and S τ Perform tomographic inversion to obtain the final relative transmittance coefficient distribution T(x);

[0105] The stress anomaly analysis module is used to calculate the average value of V(x). and deviation value And The region is designated as a stress anomaly zone. A region is considered a positive anomaly, and vice versa;

[0106] The anomaly analysis module is used to determine possible anomalous geological structures based on the relative transmission coefficient distribution T(x).

Claims

1. A method for borehole-to-bore seismic advance detection, characterized in that, The method specifically includes the following steps: Step 1: Use a trajectory measuring instrument to measure the corresponding borehole trajectory in the completed borehole A, and use the borehole trajectory to calculate the borehole coordinates x(L) corresponding to different borehole depths L. Step 2: Install multiple seismic sensors in series at equal intervals in borehole A, and connect the seismic sensor located at the borehole opening to the external data acquisition system. The depth of the seismic sensor in borehole A is denoted as L. i , where i is the serial number of the earthquake sensor; Step 3: Seal borehole A; Step four: Interpolate the borehole coordinates x(L) corresponding to different borehole depths L to obtain the coordinates x of each seismic sensor. i ; Step 5: Set the sampling rate f, gain, and data storage location of the data acquisition system, and enable real-time acquisition; Step 6: Save the collected data F over a period of time. i (t), for a set of real-time collected data F i (t) is preprocessed to obtain the cross-correlation travel time ΔT ij and the corresponding cross-correlation coefficient c ij ; Step 7: Calculate the data quality evaluation coefficient σ according to the following formula, and determine whether σ≥θ is satisfied. If yes, proceed to step 8; otherwise, return to step 6. in: N is the number of seismic sensors; θ is a given threshold; Step 8: Employ a method based on double-difference inversion and cross-correlation travel time ΔT. ij The inversion yields the current time τ and the location S of the drill bit source. τ And the seismic wave velocity distribution V on the curved surface formed by the drill bit and borehole A τ (x); Step nine, employing relative transmission coefficient tomography and cross-correlation coefficient c ij Seismic wave velocity distribution V τ (x) and the location S of the drill bit vibration source τ The transmission coefficient distribution T on the curved surface formed by the drill bit and borehole A is obtained. τ (x); Step 10: Obtain the velocity distribution V according to the following formula. ′ (x) and transmission coefficient distribution T ′ (x); Step 11: Set the current drill bit vibration source position S τ Velocity distribution V ′ (x) and transmission coefficient distribution T ′ (x) Transmitted to external display software in real time; Step 12: Return to Step 6 until hole B is completed; Step thirteen, utilize all obtained ΔT ij and S τ Perform tomographic inversion to obtain the final velocity distribution V(x); Step fourteen, utilize all obtained c ij and S τ Perform tomographic inversion to obtain the final relative transmittance coefficient distribution T(x); Step 15: Calculate the average value of V(x). The deviation of V(x) is calculated using formula (4). And The region is designated as a stress anomaly zone. A region is considered a positive anomaly, and vice versa; Step 16: Determine possible abnormal geological structures based on the relative transmission coefficient distribution T(x).

2. The borehole-to-hole seismic advance detection method as described in claim 1, characterized in that, In step six, a set of real-time collected data F is processed. i (t) is preprocessed to obtain the cross-correlation travel time ΔT ij and the corresponding cross-correlation coefficient c ij ; Step 6.1, process the collected data F i (t) is subjected to bandpass filtering to obtain the filtered acquired data F. i ′ (t); Step 6.2, process the filtered acquired data F i ′ (t) Perform a Fourier transform to obtain the frequency domain acquisition data. Step 6.3, process the collected data using the following formula. Perform pairwise cross-correlation interference to obtain cross-correlation data. in: i and j both represent the serial numbers of the seismic sensors, i≠j; "*" indicates complex conjugation; ε is a positive number; Step 6.4, cross-correlation data Performing an inverse Fourier transform yields the cross-correlation data F in the time domain. i ′ j (t), in each cross-correlation data F i ′ j Pick the cross-correlation travel time ΔT on (t) ij and the corresponding cross-correlation coefficient c ij .

3. The borehole-to-hole seismic advance detection method as described in claim 1 or 2, characterized in that, In step five, the sampling rate f of the data acquisition system is in the range of 1000Hz to 4000Hz.

4. The borehole-to-hole seismic advance detection method as described in claim 1 or 2, characterized in that, In step two, the spacing between the seismic sensors is 2 to 5 meters; the number of seismic sensors is at least 12, and the bandwidth of the seismic sensors is 5 Hz to 500 Hz.

5. The borehole-to-hole seismic advance detection method as described in claim 1 or 2, characterized in that, In step three, foam adhesive is used to seal hole A.

6. A borehole-to-bore seismic advance detection system, characterized in that, The borehole-to-hole seismic advance detection method according to any one of claims 1 to 5 includes a trajectory measurement module, a data acquisition module, a data processing module, a CT tomography inversion module, a stress anomaly analysis module, and a structural anomaly analysis module. The trajectory measurement module is used to measure the corresponding borehole trajectory in the completed borehole A using a trajectory measuring instrument, and to calculate the borehole coordinates x(L) at different borehole depths L using the borehole trajectory. It also interpolates the borehole coordinates x(L) at different borehole depths L to obtain the coordinates x of each seismic sensor. i ; The data acquisition module is used to deploy multiple series-connected seismic sensors at equal intervals in borehole A, connect the seismic sensor located at the borehole opening to the external data acquisition system, and set the sampling rate f, gain and data storage location of the data acquisition system to enable real-time acquisition. The data processing module is used to store the collected data F over a period of time. i (t), for a set of real-time collected data F i (t) is preprocessed to obtain the cross-correlation travel time ΔT ij and the corresponding cross-correlation coefficient c ik The method based on double-difference inversion and cross-correlation travel time ΔT is adopted. ij The inversion yields the current time τ and the location S of the drill bit source. τ And the seismic wave velocity distribution V on the curved surface formed by the drill bit and borehole A τ (x); relative transmission coefficient tomography and cross-correlation coefficient c were employed. ij Seismic wave velocity distribution V τ (x) and the location S of the drill bit vibration source τ The transmission coefficient distribution T on the curved surface formed by the drill bit and borehole A is obtained. τ (x); obtain the velocity distribution V ′ (x) and transmission coefficient distribution T ′ (x); The CT tomography inversion module is used to utilize all obtained ΔT ij and S τ Perform tomographic inversion to obtain the final velocity distribution V(x); use all obtained c ij and S τ Perform tomographic inversion to obtain the final relative transmittance coefficient distribution T(x); The stress anomaly analysis module is used to calculate the average value of V(x). and deviation value And The region is designated as a stress anomaly zone. A region is considered a positive anomaly, and vice versa; The aforementioned structural anomaly analysis module is used to determine possible abnormal geological structures based on the relative transmission coefficient distribution T(x).

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