Methods, apparatus, equipment and storage media for calculating quality factor Q value

Abstract

This disclosure relates to a method, apparatus, equipment, and storage medium for calculating the quality factor Q value. The method includes: sequentially numbering multiple geophone positions set in a single well; according to the matching relationship between the numbered geophone positions and the firing sequence, during each firing, using the geophone string at the multiple geophone positions corresponding to the firing sequence as a receiving channel to collect the seismic waves received by the geophone string; correcting the seismic waves corresponding to different geophone depths based on the receiving channels located at the same positions for the preceding and following firing sequences; correcting the centroid frequency and variance of the first arrival wave based on the relationship model between the centroid frequency and variance of the first arrival wave in the corrected seismic waves and the receiving depth; calculating the Q value corresponding to each receiving channel based on the corrected centroid frequency and variance of the first arrival wave. The method uses a multi-stage geophone string in the well to repeatedly receive multiple segments combined with wavelet correction to eliminate the wavelet inconsistency problem between different firing sequences.

Description

Technical Field

[0001] This disclosure relates to the field of geophysical exploration technology, and in particular to a method, apparatus, equipment and storage medium for calculating the quality factor Q value. Background Technology

[0002] In recent years, exploration workers have recognized that obtaining accurate near-surface Q values ​​is a crucial foundation for Q-compensation processing, thereby improving the quality of seismic data. Currently, near-surface Q values ​​are primarily obtained through field operations using dual-well micrologging, and then calculated indoors using the centroid frequency shift method or spectral ratio method.

[0003] Near-surface Q-value surveys are typically conducted using a dual-well micrologging method, with excitation and reception occurring in two separate wells. Different excitation-reception combinations using the centroid frequency method or spectral ratio method can yield relatively accurate near-surface Q-values. However, this method requires drilling two wells in the field, and the geophones embedded in the receiving well cannot be removed, resulting in high construction costs. Furthermore, the inconsistencies in the coupling conditions of the surrounding rock during excitation and reception in the wells lead to numerous variables, making it difficult to meet conditions such as constant excitation wavelet and consistent receiving coupling. Additionally, the interference from virtual reflection wavefields near the near-surface or high-velocity tops also reduces the accuracy of Q-value calculations.

[0004] To eliminate problems such as wavefield interference, some researchers have developed a survey method that combines in-well excitation with integrated well-to-surface observation. However, this method adds a surface receiver array to the existing dual-well micrologging, resulting in higher exploration costs and less than ideal calculation accuracy. Other technicians have explored a method of using surface explosives to excite multi-stage in-well receivers for Q-value surveys, but only energy correction was performed. Because the inconsistencies of the excitation wavelet and the effects of wavefield interference were not eliminated, the estimation accuracy was low, and non-explosive excitation methods have not been explored.

[0005] The widespread application of controlled seismic sources has led to an increase in data acquisition projects using non-explosive methods. However, using explosives for Q-value absorption attenuation surveys requires separate approval and the use of civilian explosives, thus increasing exploration costs. Surface-activated detonators increase safety risks during construction, and their use is prohibited in sensitive areas, reducing accessibility.

[0006] As Q-value surveys gain increasing importance, the number of Q-value survey deployments in seismic acquisition projects is gradually increasing. Currently, Q-value survey methods are relatively expensive. Optimizing Q-value survey methods to reduce construction costs can achieve the goal of cost reduction and efficiency improvement. With the continuous development of controllable source green exploration technology, how to reduce construction costs while ensuring the accuracy of Q-value surveys and avoiding the use of explosives has become an urgent problem to be solved. Summary of the Invention

[0007] To solve the above-mentioned technical problems, or at least partially solve them, embodiments of this disclosure provide a method, apparatus, device, and storage medium for calculating the quality factor Q value.

[0008] In a first aspect, embodiments of this disclosure provide a method for calculating the quality factor Q value, the method comprising:

[0009] The locations of multiple geophones set in a single well are numbered sequentially, and the numbered geophone locations are matched with the firing blasts.

[0010] According to the matching relationship between the geophone positions and the firing blasts, when each firing is performed at a preset distance from the wellhead, the geophone string at the multiple geophone positions corresponding to the firing blast is used as the receiving channel to collect the seismic waves received by the geophone string. The geophone strings corresponding to two adjacent firing blasts are the same, and the position of the geophone string of the subsequent firing blast is the position of the channel after the preceding firing blast is increased by a preset multiple. The preset multiple is the number of geophones contained in the geophone string minus 1, so that the preceding firing blast and the subsequent firing blast have receiving channels located at the same position.

[0011] Based on the receiving channels of the front and rear guns located at the same position, the seismic waves corresponding to different detector depths are corrected.

[0012] The centroid frequency and variance of the first arrival wave in the corrected seismic waves corresponding to different detector depths are calculated, and the centroid frequency and variance of the first arrival wave are corrected based on the relationship model between the centroid frequency and variance of the first arrival wave and the receiving depth.

[0013] Based on the centroid frequency and variance of the first arrival wave of each receiving channel at different detector depths that have been calibrated, the Q value corresponding to each receiving channel is calculated.

[0014] In one possible implementation, the step of matching the geophone positions with the firing blasts according to the numbered geophone positions, and performing each firing at a preset distance from the wellhead, uses the geophone string at the multiple geophone positions corresponding to the firing blast as a receiving channel to collect the seismic waves received by the geophone string, including:

[0015] The first step is that when the Nth shot is fired, the geophone in the well is placed at the well section position corresponding to the geophone points numbered (i-1)×(N-1)+1 to (i-1)×(N-1)+i, where i is the number of receiving channels corresponding to each firing shot, and N is the number of shots.

[0016] The second step is to raise the geophone to a distance of i-1 times the track spacing after the Nth shot acquisition is completed, and then perform the N+1th shot acquisition. The geophone in the well is placed at the well section position corresponding to the geophone points numbered (i-1)×(N-1)+i to (i-1)×N+i to receive the data.

[0017] The third step is to collect data in sequence, following the steps one and two, until data collection for the entire well section is completed.

[0018] In one possible implementation, the receiver channels at the same position as the front and rear guns are the last receiver channel of the front gun and the first receiver channel of the rear gun. The correction of seismic waves corresponding to different detector depths based on the receiver channels at the same position of the front and rear guns includes:

[0019] The first step is to use the data from the first receiving channel of the rear gun as the data to be corrected and the data from the last receiving channel of the front gun as the expected output data, based on the principle of shaping filtering. The shaping filtering operator is then used to correct the data from other receiving channels of the rear gun in order to eliminate the inconsistency of the excitation wavelet between the data of the front and rear guns.

[0020] The second step involves performing shaping and filtering on the data between adjacent shots in sequence, following the steps in the first step, to complete the excitation wavelet non-uniformity correction for all seismic waves corresponding to different detector depths.

[0021] In one possible implementation, the correction of the centroid frequency and variance of the first arrival wave based on the relationship model between the centroid frequency and variance of the first arrival wave and the receiving depth includes:

[0022] Based on the Laida criterion, outliers in the model relating the centroid frequency of the first arrival wave to the receiving depth are eliminated.

[0023] Based on the relationship model between the centroid frequency of the first arrival wave after removing outliers and the receiving depth, the centroid frequency of the first arrival wave of each receiving channel is calculated according to the receiving depth.

[0024] Based on the Laida criterion, outliers in the model relating the centroid variance of the first arrival wave to the receiving depth are removed.

[0025] Based on the relationship model between the centroid variance of the first arrival wave after outlier removal and the receiving depth, the centroid variance of the first arrival wave for each receiving channel is calculated according to the receiving depth.

[0026] In one possible implementation, calculating the Q value corresponding to each receiving channel based on the centroid frequency and variance of the first arrival wave of each receiving channel at different detector depths after calibration includes:

[0027]

[0028] Where, σ s To correct for the variance of the first arrival wave before attenuation in the current receiver channel, which is affected by the complex wave field, Δt is the time difference between the arrival times of the first arrival wave before and after attenuation in the current receiver channels at different depths, f sTo correct the centroid frequency of the current receiving channel before the first arrival wave attenuation, which is affected by complex wave fields, f R The centroid frequency of the current receiving channel after the first arrival wave attenuation has been corrected due to the influence of complex wave fields.

[0029] In one possible implementation, the method further includes:

[0030] The seismic velocity model is calculated based on the first arrival time acquired at different geophone depths, wherein the seismic velocity model includes the correspondence between depth and velocity;

[0031] Based on the earthquake velocity model, the correspondence between velocity and Q value is obtained according to the Q value corresponding to each receiver channel.

[0032] In one possible implementation, before calculating the seismic velocity model based on the first arrival times acquired at different detector depths, the method further includes:

[0033] A geophone is set at a first preset distance from the wellhead, and the arrival time of the direct wave of multiple firing shots is recorded in advance. The average value of the recorded arrival times of the direct wave is calculated.

[0034] The arrival time of the direct wave from each firing shot is used to correct the first arrival time of the data collected at different geophone depths, and the seismic velocity model is calculated based on the corrected first arrival time.

[0035] Secondly, embodiments of this disclosure provide a device for calculating the quality factor Q value, comprising:

[0036] The matching module is used to sequentially number the multiple geophone positions set in a single well and match the numbered geophone positions with the firing blasts.

[0037] The acquisition module is used to acquire seismic waves received by the geophone strings at multiple geophone positions corresponding to the excitation shot, according to the matching relationship between the geophone positions after numbering and the excitation shot. During each excitation at a preset distance from the wellhead, the geophone strings corresponding to the multiple geophone positions of the excitation shot are used as receiving channels. The geophone strings corresponding to two adjacent excitation shots are the same, and the position of the geophone string of the subsequent shot is the position of the channel spacing of the preceding shot after increasing the channel spacing by a preset multiple. The preset multiple is the number of geophones contained in the geophone string minus 1, so that the preceding shot and the subsequent shot have receiving channels located at the same position.

[0038] The correction module is used to correct seismic waves corresponding to different detector depths based on the receiving channels of the front and rear guns located at the same position.

[0039] The first calculation module is used to calculate the centroid frequency and variance of the first arrival wave in the corrected seismic waves corresponding to different detector depths, and to correct the centroid frequency and variance of the first arrival wave based on the relationship model between the centroid frequency and variance of the first arrival wave and the receiving depth.

[0040] The second calculation module is used to calculate the Q value corresponding to each receiving channel based on the centroid frequency and variance of the first arrival wave of each receiving channel at different detector depths that have been calibrated.

[0041] Thirdly, embodiments of this disclosure provide an electronic device, including a processor, a communication interface, a memory, and a communication bus, wherein the processor, the communication interface, and the memory communicate with each other via the communication bus;

[0042] Memory, used to store computer programs;

[0043] The processor, when executing a program stored in memory, implements the above-mentioned method for calculating the quality factor Q value.

[0044] Fourthly, embodiments of this disclosure provide a computer-readable storage medium having a computer program stored thereon, characterized in that the computer program, when executed by a processor, implements the above-described method for calculating the quality factor Q value.

[0045] Compared with the prior art, the technical solutions provided in this disclosure have at least some or all of the following advantages:

[0046] The method for calculating the quality factor Q value described in this embodiment involves sequentially numbering multiple geophone positions in a single well and matching the numbered geophone positions with the firing blast sequence. Based on this matching relationship, during each firing at a preset distance from the wellhead, the geophone string at the corresponding geophone positions is used as a receiving channel to collect the seismic waves received by the geophone string. The geophone strings corresponding to two adjacent firing blasts are identical, and the position of the geophone string in the subsequent blast is the position of the preceding blast after increasing the channel spacing by a preset multiple, where the preset multiple is the number of geophones in the geophone string minus one, ensuring that the preceding and subsequent blasts have receiving channels at the same position. Based on these receiving channels at the same position, seismic waves corresponding to different geophone depths are corrected. The centroid frequency and variance of the first arrival wave in the corrected seismic waves corresponding to different detector depths are calculated. Based on the relationship model between the centroid frequency and variance of the first arrival wave and the receiving depth, the centroid frequency and variance of the first arrival wave are corrected. According to the centroid frequency and variance of the first arrival wave of each receiving channel at different detector depths that have been corrected, the Q value corresponding to each receiving channel is calculated. Multiple excitations at the same location using a surface hammer combined with surface-corrected detectors can not only avoid the use of explosives but also ensure the stability of the excitation time. Using a multi-stage detector series in the well to repeat one segment of reception combined with wavelet correction eliminates the wavelet inconsistency problem between different excitation times. Using model inversion to fit the centroid frequency, variance, and first arrival time of different receiving points can eliminate the influence of virtual reflection interference near the high-speed top and improve the accuracy of Q value estimation by the centroid frequency migration method. Attached Figure Description

[0047] The accompanying drawings, which are incorporated in and form a part of this specification, illustrate embodiments consistent with this disclosure and, together with the description, serve to explain the principles of this disclosure.

[0048] To more clearly illustrate the technical solutions in the embodiments of this disclosure or the prior art, the accompanying drawings used in the description of the embodiments or related technologies will be briefly introduced below. Obviously, those skilled in the art can obtain other drawings based on these drawings without creative effort.

[0049] Figure 1 A schematic flowchart illustrating a method for calculating the quality factor Q value according to an embodiment of the present disclosure is shown.

[0050] Figure 2(a) schematically illustrates the construction of a multi-stage receiver absorption attenuation survey in the Nth MVSP surface excitation well according to an embodiment of the present disclosure;

[0051] Figure 2(b) schematically illustrates the construction diagram of the multi-stage receiver absorption attenuation survey in the N+1th MVSP surface excitation well according to an embodiment of the present disclosure;

[0052] Figure 3(a) schematically illustrates the surface correction detector records for different shots before correction according to an embodiment of the present disclosure;

[0053] Figure 3(b) schematically illustrates the surface correction detector records for different shots after correction according to an embodiment of the present disclosure;

[0054] Figure 4(a) schematically illustrates a model of the relationship between the centroid frequency of the first arrival wave and the receiving depth (60m deep at the top surface of the high-speed wave) according to an embodiment of the present disclosure;

[0055] Figure 4(b) schematically illustrates a model of the relationship between the variance of the centroid of the first arrival wave and the receiving depth (60m deep at the top surface of the high-speed wave) according to an embodiment of the present disclosure.

[0056] Figure 5 The diagram illustrates the relationship between Q values ​​obtained by different calculation methods and the burial depth of the strata.

[0057] Figure 6(a) schematically illustrates the relationship between the first-arrival centroid frequency and the reception depth at an actual absorption attenuation survey point according to an embodiment of the present disclosure;

[0058] Figure 6(b) schematically illustrates the relationship between the first-arrival centroid calculation and the receiving depth at an actual absorption attenuation survey point according to an embodiment of the present disclosure;

[0059] Figure 7 A schematic block diagram illustrating an apparatus for calculating the quality factor Q value according to an embodiment of the present disclosure is shown; and

[0060] Figure 8 A schematic block diagram of an electronic device according to an embodiment of the present disclosure is shown. Detailed Implementation

[0061] To make the objectives, technical solutions, and advantages of the embodiments of this disclosure clearer, the technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this disclosure. Based on the embodiments of this disclosure, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this disclosure.

[0062] See Figure 1 The embodiments of this disclosure provide a method for calculating the quality factor Q value, the method comprising:

[0063] S1, number the multiple geophone positions set in a single well in sequence, and match the numbered geophone positions with the firing blasts;

[0064] S2, according to the matching relationship between the geophone positions after the number and the excitation shot, when each heavy hammer blow is performed at a preset distance from the wellhead, the geophone string at the multiple geophone positions corresponding to the excitation shot is used as the receiving channel to collect the seismic waves received by the geophone string. Among them, the geophone strings corresponding to two adjacent excitation shots are the same, and the position of the geophone string of the subsequent shot is the position of the channel after the preceding shot is increased by a preset multiple. The preset multiple is the number of geophones contained in the geophone string minus 1, so that the preceding shot and the subsequent shot have receiving channels located at the same position.

[0065] S3, based on the receiving channels of the front and rear guns located at the same position, corrects the seismic waves corresponding to different detector depths;

[0066] S4. Calculate the centroid frequency and variance of the first arrival wave in the corrected seismic waves corresponding to different detector depths, and correct the centroid frequency and variance of the first arrival wave based on the relationship model between the centroid frequency and variance of the first arrival wave and the receiving depth.

[0067] S5. Based on the centroid frequency and variance of the first arrival wave of each receiving channel at different detector depths that have been calibrated, the Q value corresponding to each receiving channel is calculated.

[0068] In this embodiment, in step S2, the step of matching the geophone positions with the firing blasts according to the numbered geophone positions, and performing each firing at a preset distance from the wellhead, using the geophone string at the multiple geophone positions corresponding to the firing blast as a receiving channel to collect the seismic waves received by the geophone string, includes:

[0069] The first step is that when the Nth shot is fired, the geophone in the well is placed at the well section position corresponding to the geophone points numbered (i-1)×(N-1)+1 to (i-1)×(N-1)+i, where i is the number of receiving channels corresponding to each firing shot, and N is the number of shots.

[0070] The second step is to raise the geophone to a distance of i-1 times the track spacing after the Nth shot acquisition is completed, and then perform the N+1th shot acquisition. The geophone in the well is placed at the well section position corresponding to the geophone points numbered (i-1)×(N-1)+i to (i-1)×N+i to receive the data.

[0071] The third step is to collect data in sequence, following the steps one and two, until data collection for the entire well section is completed.

[0072] In this embodiment, in step S3, the receiving channels of the front and rear guns located at the same position are the last receiving channel of the front gun and the first receiving channel of the rear gun. The step of correcting the seismic waves corresponding to different detector depths based on the receiving channels of the front and rear guns located at the same position includes:

[0073] The first step is to use the data from the first receiving channel of the rear gun as the data to be corrected and the data from the last receiving channel of the front gun as the expected output data, based on the principle of shaping filtering. The shaping filtering operator is then used to correct the data from other receiving channels of the rear gun in order to eliminate the inconsistency of the excitation wavelet between the data of the front and rear guns.

[0074] The second step involves performing shaping and filtering on the data between adjacent shots in sequence, following the steps in the first step, to complete the excitation wavelet non-uniformity correction for all seismic waves corresponding to different detector depths.

[0075] In this embodiment, step S4, which involves correcting the centroid frequency and variance of the first arrival wave based on the relationship model between the centroid frequency and variance of the first arrival wave and the receiving depth, includes:

[0076] Based on the Laida criterion, outliers in the model relating the centroid frequency of the first arrival wave to the receiving depth are eliminated.

[0077] Based on the relationship model between the centroid frequency of the first arrival wave after removing outliers and the receiving depth, the centroid frequency of the first arrival wave of each receiving channel is calculated according to the receiving depth.

[0078] Based on the Laida criterion, outliers in the model relating the centroid variance of the first arrival wave to the receiving depth are removed.

[0079] Based on the relationship model between the centroid variance of the first arrival wave after outlier removal and the receiving depth, the centroid variance of the first arrival wave for each receiving channel is calculated according to the receiving depth.

[0080] In this embodiment, step S5, calculating the Q value corresponding to each receiving channel based on the centroid frequency and variance of the first arrival wave of each receiving channel at different detector depths after correction, includes:

[0081]

[0082] Where, σ s To correct for the variance of the first arrival wave before attenuation in the current receiver channel, which is affected by the complex wave field, Δt is the time difference between the arrival times of the first arrival wave before and after attenuation in the current receiver channels at different depths, f s To correct the centroid frequency of the current receiving channel before the first arrival wave attenuation, which is affected by complex wave fields, f RThe centroid frequency of the current receiving channel after the first arrival wave attenuation has been corrected due to the influence of complex wave fields.

[0083] In this embodiment, the method further includes:

[0084] The seismic velocity model is calculated based on the first arrival time acquired at different geophone depths, wherein the seismic velocity model includes the correspondence between depth and velocity;

[0085] Based on the earthquake velocity model, the correspondence between velocity and Q value is obtained according to the Q value corresponding to each receiver channel.

[0086] In this embodiment, before calculating the seismic velocity model based on the first arrival times acquired at different detector depths, the method further includes:

[0087] A geophone is set at a first preset distance from the wellhead, and the arrival time of the direct wave of multiple firing shots is recorded in advance. The average value of the recorded arrival times of the direct wave is calculated.

[0088] The arrival time of the direct wave from each firing shot is used to correct the first arrival time of the data collected at different geophone depths, and the seismic velocity model is calculated based on the corrected first arrival time.

[0089] The method for calculating the quality factor Q was applied to the northern Tarim Desert region of the Tarim Basin. This region is characterized by undulating sand dunes, with the water table at the top of the high-velocity surface and a loose sand layer above it, exhibiting near-continuous medium characteristics. Velocity gradually increases with depth. The MVSP (Multi-Voltage-Side Platform) construction method was used to complete the construction and calculation of multiple Q-value absorption attenuation survey points, ensuring survey accuracy while reducing construction costs and safety risks. The specific implementation details for one absorption attenuation survey point are as follows:

[0090] 1) At the absorption attenuation survey points, detectors and excitation points are deployed using the MVSP single-well method.

[0091] Step 1) Drill one well at the absorption attenuation survey point location according to the designed survey depth as the MVSP receiving well, and design n receiving points in the well. The hammer excitation position is set at the surface at a distance of x meters from the wellhead, ensuring that the excitation position remains unchanged for each iteration. A verification geophone is deployed around the wellhead in a location that does not interfere with construction, simultaneously receiving signals from the geophone in the MVSP well. Its function is to record the arrival time of the direct wave from each hammer excitation, thus eliminating the time delay difference between different excitation bursts. See [link to relevant documentation]. Figure 1 During the acquisition process, it is essential to ensure that the detector is in a fixed position and well coupled.

[0092] In practical applications, the surface database established based on surface data can roughly determine the thickness of the low-velocity layer at the absorption attenuation survey point to be approximately 29m. Only one well was completed, with a drilling depth of 50m. MVSP construction was employed, with 51 receiving points designed within the well. These 51 receiving points were numbered sequentially from bottom to top, starting with 1, with a distance of 1m between each receiving point. The excitation point was designed to be 2m away from the receiving well to ensure that the excitation position remained consistent for each iteration. A verification geophone was buried 1m from the wellhead on the surface. Its function was to record the arrival time of the direct wave from each hammer excitation, thus eliminating time delays between different excitation runs (see Figure 2).

[0093] 2) Multi-stage receivers in MVSP wells complete absorption attenuation survey data acquisition.

[0094] Step 2) Use multi-stage geophones in the MVSP well to receive seismic waves excited by surface hammers in multiple segments to complete the absorption attenuation survey data acquisition. Number the n receiving points in the receiving well sequentially from bottom to top starting from 1. Using the MVSP method, start receiving from receiving point 1 at the bottom of the well with the i-th stage geophone.

[0095] Considering the inconsistency of excitation wavelets between different hammer-triggered shots when using multi-stage in-well geophones, an improvement is made to the conventional MVSP in-well micro-logging method to eliminate this inconsistency and improve the accuracy of Q-value estimation. A duplicate receiving channel (the receiving record of a single seismic geophone, referred to as a seismic channel) is set at the junction of the receiving ranges of adjacent shots. This means that the last receiving channel of the preceding shot and the first receiving channel of the following shot are located at the same receiving position, thus eliminating the inconsistency of excitation wavelets between adjacent shots. A schematic diagram of the observation method is shown in Figure 2. During the Nth shot, the in-well geophone is placed at the well section corresponding to the geophone points numbered (i-1)×(N-1)+1 to (i-1)×(N-1)+i, as shown below. Figure 2a After the Nth shot acquisition is completed, the geophone is raised by a distance of i-1 times the channel spacing to acquire the N+1th shot. The geophone in the well is placed at the well section position corresponding to the geophone points numbered (i-1)×(N-1)+i to (i-1)×N+i to receive data. Figure 2b Collect data sequentially until data acquisition for the entire well section is complete.

[0096] In practical application, this MVSP method construction used a 6-stage in-well geophone string to receive data starting from receiver point 1 at the bottom of the well, and excitation was performed using a 12-pound hammer on the ground. The first blast's receiver points were from 1 to 6. After the first blast's data acquisition was completed, the 6-stage in-well geophone string was raised 5 receiver intervals, i.e., raised 5m, to conduct absorption attenuation surveys for the second blast's data acquisition. At this time, the bottom geophone in the second blast's in-well geophone string coincided with the top geophone in the first blast (both were at receiver point 6). This overlap between the second and first blasts served as the basis for subsequent shaping and filtering to eliminate excitation wavelet inconsistencies.

[0097] The MVSP detector string is sequentially raised for segmented acquisition. When the Nth shot is fired by the hammer, the detectors in the well are positioned at the well sections corresponding to the detector points numbered 5×(N-1)+1 to 5×(N-1)+6 to receive data. Figure 2a After the Nth shot acquisition is completed, the geophone is raised to a distance of 5 times the track spacing to acquire the N+1th shot. The geophone in the well is placed at the well section corresponding to the geophone points numbered 5×(N-1)+6 to 5×N+6 to receive data. Figure 2b Collect data sequentially until data acquisition for the entire well section is complete.

[0098] 3) Use the repeat channel of the multi-stage geophone in the MVSP well for hammer-excited wavelet consistency correction.

[0099] Step 3) Use the repeated receiving channels of the multi-stage detector in the MVSP well to eliminate the non-uniformity of the excitation wavelet between different excitation shots through waveform correction.

[0100] In digital signal processing, shaping filtering can eliminate wavelet consistency differences between records from different sources. The principle is to input the data to be corrected and the desired output data, and within a certain time and space range, use the Wiener filtering algorithm to derive a shaping filter operator. This operator is then applied to the data to be corrected, thus eliminating the difference between the input data and the desired output data. Ideally, the first arrival waves received by the verification detector should have the same start time and consistent waveform. However, in actual data acquisition, the start time and waveform of the records received by the verification detector differ somewhat between different shots. Figure 3a This reflects the problems of recording delay time difference and excitation wavelet inconsistency between different firing cycles.

[0101] Based on the basic principle of the shaping filter processing method, the first data of the rear gun is taken as the data to be corrected and the last data of the front gun is taken as the expected output data. The shaping filter operator is calculated and then applied to the data of other channels of the rear gun, thereby eliminating the inconsistency of the excitation wavelet between the data of the front and rear guns.

[0102] The data between two adjacent shots are sequentially shaped and filtered, and the excitation wavelet non-uniformity correction is completed for the absorption attenuation survey data of all MVSP multi-segment reception. Figure 3b The waveforms of the excitation wavelet before and after non-uniformity correction were recorded for different shots of the surface verification detector. It can be seen that after the excitation wavelet non-uniformity correction by shaping filter, the waveform morphology uniformity is significantly improved, and the influence of excitation wavelet non-uniformity on the Q value calculation result is eliminated.

[0103] 4) Model inversion fitting eliminates the influence of virtual reflection wave field at the high-speed top interface.

[0104] Step 4) When conducting absorption attenuation surveys using MVSP ground-excited well receivers, well receivers near the top of the high-speed wave will experience interference between the reflected wave and the direct wave field, resulting in complex waveforms. These affected waveforms will cause anomalies in the centroid frequency and variance, leading to abnormal Q-values ​​that cannot be used for Q-value estimation. As shown in Figure 4, five consecutive receivers at depths above 60m from the top of the high-speed wave exhibited anomalies in both centroid frequency and variance. Based on velocity and thickness data at the actual Q-value survey locations, a forward and inverse model based on the wave equation can be performed to eliminate abnormal data points.

[0105] In actual data, the centroid frequency and variance of the first arrival wave have a nonlinear relationship with the receiving depth. Using polynomial fitting to fit the whole has a high degree of similarity. The trend of the centroid frequency and variance of the first arrival wave with the receiving depth of the seismic trace affected by high-speed top surface reflection wave interference is significantly different from that of other traces. After removing outliers, the shape of the fitted curve can more objectively reflect the trend of the centroid frequency and variance of the first arrival wave with the receiving depth.

[0106] The collected absorption attenuation survey data were preprocessed to pick and extract the first arrival wave. The centroid frequency and centroid calculation were calculated for the first arrival wave corresponding to different depth detectors. Polynomial fitting was performed to obtain the relationship formulas between the centroid frequency and depth of the first arrival wave and between the calculated centroid of the first arrival wave and depth. Outliers were iteratively removed based on the Laida criterion. After removing outliers, the polynomial fitting formula was obtained. Figure 5 To eliminate anomalies near the high-speed top surface, curves and polynomial formulas for centroid frequency versus depth and variance versus depth are derived. Using the fitting formula and substituting the depth, the first-arrival centroid frequency and variance of each trace are calculated, including the corresponding depths of those affected by complex wave fields that have already been eliminated, for Q-value estimation.

[0107] Figure 6 shows a comparison between the Q-values ​​calculated before and after removing the centroid frequencies and variances of the anomalous first arrival waves and the equivalent Q-values ​​of the model theory. As can be seen from the figure, after removing the anomalous centroid frequencies and variances of the first arrival waves, the calculated Q-values ​​are closer to the theoretical values ​​of the model, and the accuracy is higher.

[0108] 5) Estimate the Q-value based on the data after model inversion and fitting.

[0109] Step 5) The centroid frequencies and variances of the first arrival waves at different detector depths, calculated according to the model inversion fitting formula, are calculated based on the centroid frequency method. The Q values ​​at different depths of the absorption attenuation survey point are then calculated by comparing them with the near-surface structural layer interpretation results, i.e., the Q values ​​for each layer, as shown in Table 1. Table 1 shows that, except for strata within 2m below the surface, the Q values ​​obtained by the method disclosed in this paper are close to the Q values ​​obtained by Li Qingzhong's empirical formula.

[0110] Table 1

[0111]

[0112] The above five steps complete the entire process of conducting absorption attenuation investigation using multi-stage geophones in the well with MVSP surface hammer excitation, eliminating the non-uniformity of the excitation wavelet through repetition channels and eliminating the influence of virtual reflections from the high-speed top surface through model inversion fitting, and finally obtaining the Q value.

[0113] The calculation method provided in this disclosure solves the problems of high safety risks and high construction costs associated with Q-value absorption attenuation surveys using dual-well micro-logging explosive excitation. By using surface heavy hammer excitation, the use of explosive sources is avoided. Multi-stage geophones in the MVSP well repeatedly receive multiple segments, eliminating the problem of non-consistency in the excitation wavelet. Model inversion fitting is used to eliminate the influence of virtual reflections at the high-speed top interface, thereby achieving the goal of ensuring the accuracy of Q-value surveys and reducing construction costs and safety risks.

[0114] The method disclosed herein relates to a method for investigating near-surface Q-value absorption attenuation in seismic exploration. It can be applied to onshore two-dimensional and three-dimensional seismic exploration. When conducting near-surface Q-value absorption attenuation investigations, it provides a construction method and calculation method that ensures investigation accuracy and reduces construction costs.

[0115] The method disclosed herein uses a heavy hammer to avoid the use of explosives, employs MVSP multi-stage well reception and repeats one cycle combined with model inversion fitting to improve the accuracy of Q value calculation, reduces the number of wells drilled from 2 to 1, and since MVSP does not require well sealing, the well can be reused as a production well, thus improving the economy of the absorption attenuation investigation method.

[0116] See Figure 7 Embodiments of this disclosure provide a device for calculating the quality factor Q, comprising:

[0117] Matching module 11 is used to sequentially number the positions of multiple geophones set in a single well and match the numbered geophone positions with the firing blasts.

[0118] The acquisition module 12 is used to acquire the seismic waves received by the geophone strings at multiple geophone positions corresponding to the excitation shot number, according to the matching relationship between the geophone positions and the excitation shot number. During each excitation at a preset distance from the wellhead, the geophone strings corresponding to the excitation shot number are used as receiving channels. The geophone strings corresponding to two adjacent excitation shots are the same, and the position of the geophone string of the subsequent shot is the position of the channel spacing after the preceding shot is increased by a preset multiple. The preset multiple is the number of geophones contained in the geophone string minus 1, so that the preceding shot and the subsequent shot have receiving channels located at the same position.

[0119] Correction module 13 is used to correct seismic waves corresponding to different detector depths based on the receiving channels of the front and rear guns located at the same position.

[0120] The first calculation module 14 is used to calculate the centroid frequency and variance of the first arrival wave in the corrected seismic waves corresponding to different detector depths, and to correct the centroid frequency and variance of the first arrival wave based on the relationship model between the centroid frequency and variance of the first arrival wave and the receiving depth.

[0121] The second calculation module 15 is used to calculate the Q value corresponding to each receiving channel based on the centroid frequency and variance of the first arrival wave of each receiving channel at different detector depths that have been calibrated.

[0122] The specific implementation process of the functions and roles of each unit in the above device can be found in the implementation process of the corresponding steps in the above method, and will not be repeated here.

[0123] For the device embodiments, since they basically correspond to the method embodiments, the relevant parts can be referred to in the description of the method embodiments. The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of the present invention according to actual needs. Those skilled in the art can understand and implement this without creative effort.

[0124] In the second embodiment described above, any plurality of the matching module 11, acquisition module 12, correction module 13, first calculation module 14, and second calculation module 15 can be combined into one module, or any one of these modules can be split into multiple modules. Alternatively, at least part of the functionality of one or more of these modules can be combined with at least part of the functionality of other modules and implemented in one module. At least one of the matching module 11, acquisition module 12, correction module 13, first calculation module 14, and second calculation module 15 can be at least partially implemented as hardware circuitry, such as a field-programmable gate array (FPGA), a programmable logic array (PLA), a system-on-a-chip, a system-on-a-substrate, a system-on-package, an application-specific integrated circuit (ASIC), or any other reasonable means of integrating or packaging the circuitry, or implemented in software, hardware, or firmware, or in any appropriate combination of any of these three implementation methods. Alternatively, at least one of the matching module 11, acquisition module 12, correction module 13, first calculation module 14, and second calculation module 15 can be at least partially implemented as a computer program module, which can perform corresponding functions when the computer program module is run.

[0125] See Figure 8 The electronic device provided in the embodiments of this disclosure includes a processor 1110, a communication interface 1120, a memory 1130 and a communication bus 1140, wherein the processor 1110, the communication interface 1120 and the memory 1130 communicate with each other through the communication bus 1140.

[0126] Memory 1130 is used to store computer programs;

[0127] When processor 1110 executes the program stored in memory 1130, it implements the following method for calculating the quality factor Q:

[0128] Multiple geophones installed in a single well are numbered sequentially, and the positions of the numbered geophones are matched with the firing blasts. In two adjacent firing blasts, the preceding blast has at least one receiving channel located in the same position as the following blast.

[0129] According to the matching relationship between the numbered geophone positions and the firing blasts, when each firing is performed at a preset distance from the wellhead, the geophone string at the multiple geophone positions corresponding to the firing blasts is used as the receiving channel to collect the seismic waves received by the geophone string.

[0130] Based on the receiving channels of the front and rear guns located at the same position, the seismic waves corresponding to different detector depths are corrected.

[0131] The centroid frequency and variance of the first arrival wave in the corrected seismic waves corresponding to different detector depths are calculated, and the centroid frequency and variance of the first arrival wave are corrected based on the relationship model between the centroid frequency and variance of the first arrival wave and the receiving depth.

[0132] Based on the centroid frequency and variance of the first arrival wave of each receiving channel at different detector depths that have been calibrated, the Q value corresponding to each receiving channel is calculated.

[0133] The aforementioned communication bus 1140 can be a Peripheral Component Interconnect (PCI) bus or an Extended Industry Standard Architecture (EISA) bus, etc. This communication bus 1140 can be divided into an address bus, a data bus, a control bus, etc. For ease of illustration, it is represented by only one thick line in the figure, but this does not indicate that there is only one bus or one type of bus.

[0134] The communication interface 1120 is used for communication between the above-mentioned electronic device and other devices.

[0135] The memory 1130 may include random access memory (RAM) or non-volatile memory, such as at least one disk storage device. Optionally, the memory 1130 may also be at least one storage device located remotely from the aforementioned processor 1110.

[0136] The processor 1110 mentioned above can be a general-purpose processor, including a central processing unit (CPU), a network processor (NP), etc.; it can also be a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components.

[0137] Based on the same inventive concept, a fifth exemplary embodiment of this disclosure also provides a computer-readable storage medium. The computer-readable storage medium stores a computer program, which, when executed by a processor, implements the method for calculating the quality factor Q value as described above.

[0138] The computer-readable storage medium may be included in the device / apparatus described in the above embodiments; or it may exist independently and not assembled into the device / apparatus. The computer-readable storage medium carries one or more programs that, when executed, implement the method for calculating the quality factor Q value according to embodiments of this disclosure.

[0139] According to embodiments of this disclosure, the computer-readable storage medium can be a non-volatile computer-readable storage medium, such as including, but not limited to: portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination thereof. In this disclosure, the computer-readable storage medium can be any tangible medium that contains or stores a program that can be used by or in conjunction with an instruction execution system, apparatus, or device.

[0140] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0141] The above description is merely a specific embodiment of this disclosure, enabling those skilled in the art to understand or implement it. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this disclosure. Therefore, this disclosure is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A method for calculating the quality factor Q value, characterized in that, The method includes: The locations of multiple geophones set in a single well are numbered sequentially, and the numbered geophone locations are matched with the firing blasts. According to the matching relationship between the geophone positions and the firing blasts, when each firing is performed at a preset distance from the wellhead, the geophone string at the multiple geophone positions corresponding to the firing blast is used as the receiving channel to collect the seismic waves received by the geophone string. The geophone strings corresponding to two adjacent firing blasts are the same, and the position of the geophone string of the subsequent firing blast is the position of the channel after the preceding firing blast is increased by a preset multiple. The preset multiple is the number of geophones contained in the geophone string minus 1, so that the preceding firing blast and the subsequent firing blast have receiving channels located at the same position. Based on the receiving channels of the front and rear shots located at the same position, the seismic waves corresponding to different detector depths are corrected. The centroid frequency and variance of the first arrival wave in the corrected seismic waves corresponding to different detector depths are calculated, and the centroid frequency and variance of the first arrival wave are corrected based on the relationship model between the centroid frequency and variance of the first arrival wave and the receiving depth. The Q value corresponding to each receiving channel is calculated based on the centroid frequency and variance of the first arrival wave of each receiving channel at different detector depths after calibration. According to the matching relationship between the numbered geophone positions and the firing blasts, during each firing at a preset distance from the wellhead, the geophone string at the multiple geophone positions corresponding to the firing blast is used as a receiving channel to collect the seismic waves received by the geophone string, including: The first step is that when the Nth shot is fired, the geophone in the well is placed at the well section position corresponding to the geophone points numbered (i-1)×(N-1)+1 to (i-1)×(N-1)+i, where i is the number of receiving channels corresponding to each firing shot, and N is the number of shots. The second step is to raise the geophone to a distance of i-1 times the track spacing after the Nth shot acquisition is completed, and then perform the N+1th shot acquisition. The geophone in the well is placed at the well section position corresponding to the geophone points numbered (i-1)×(N-1)+i to (i-1)×N+i to receive the data. The third step is to collect data in sequence according to the first and second steps until the data collection of the entire well section is completed. The model relating the centroid frequency and variance of the first arrival wave to the receiving depth corrects the centroid frequency and variance of the first arrival wave, including: Based on the Laida criterion, outliers in the model relating the centroid frequency of the first arrival wave to the receiving depth are eliminated. Based on the relationship model between the centroid frequency of the first arrival wave after removing outliers and the receiving depth, the centroid frequency of the first arrival wave of each receiving channel is calculated according to the receiving depth. Based on the Laida criterion, outliers in the model relating the centroid variance of the first arrival wave to the receiving depth are removed. Based on the relationship model between the centroid variance of the first arrival wave after outlier removal and the receiving depth, the centroid variance of the first arrival wave for each receiving channel is calculated according to the receiving depth.

2. The method according to claim 1, characterized in that, The receiver channels of the front and rear guns located at the same position are the last receiver channel of the front gun and the first receiver channel of the rear gun. The correction of seismic waves corresponding to different detector depths based on the receiver channels of the front and rear guns located at the same position includes: The first step is to use the data from the first receiving channel of the rear gun as the data to be corrected and the data from the last receiving channel of the front gun as the expected output data, based on the principle of shaping filtering. The shaping filtering operator is then used to correct the data from other receiving channels of the rear gun in order to eliminate the inconsistency of the excitation wavelet between the data of the front and rear guns. The second step involves performing shaping and filtering on the data between adjacent shots in sequence, following the steps in the first step, to complete the excitation wavelet non-uniformity correction for all seismic waves corresponding to different detector depths.

3. The method according to claim 1, characterized in that, The calculation of the Q value corresponding to each receiving channel based on the centroid frequency and variance of the first arrival wave of each receiving channel at different detector depths after calibration includes: in, To correct for the variance of the current receiver channel before the initial arrival wave attenuation, which is affected by complex wave fields. This represents the time difference between the arrival times of the initial arrival wave before and after attenuation at different depths of the receiving channel. The centroid frequency of the current receiving channel before the first arrival wave attenuation, which has been corrected for the influence of complex wave fields. The centroid frequency of the current receiving channel after the first arrival wave attenuation has been corrected due to the influence of complex wave fields.

4. The method according to claim 1, characterized in that, The method further includes: The seismic velocity model is calculated based on the first arrival time acquired at different geophone depths, wherein the seismic velocity model includes the correspondence between depth and velocity; Based on the earthquake velocity model, the correspondence between velocity and Q value is obtained according to the Q value corresponding to each receiver channel.

5. The method according to claim 4, characterized in that, Before calculating the seismic velocity model based on the first arrival times acquired at different detector depths, the method further includes: A geophone is set at a first preset distance from the wellhead, and the arrival time of the direct wave of multiple firing shots is recorded in advance. The average value of the recorded arrival times of the direct wave is calculated. The arrival time of the direct wave from each firing shot is used to correct the first arrival time of the data collected at different geophone depths, and the seismic velocity model is calculated based on the corrected first arrival time.

6. A device for calculating the quality factor Q, characterized in that, include: The matching module is used to sequentially number the multiple geophone positions set in a single well and match the numbered geophone positions with the firing blasts. The acquisition module is used to acquire seismic waves received by the geophone strings at multiple geophone positions corresponding to the excitation shot, according to the matching relationship between the geophone positions after numbering and the excitation shot. During each excitation at a preset distance from the wellhead, the geophone strings corresponding to the multiple geophone positions of the excitation shot are used as receiving channels. The geophone strings corresponding to two adjacent excitation shots are the same, and the position of the geophone string of the subsequent shot is the position of the channel spacing of the preceding shot after increasing the channel spacing by a preset multiple. The preset multiple is the number of geophones contained in the geophone string minus 1, so that the preceding shot and the subsequent shot have receiving channels located at the same position. The correction module is used to correct seismic waves corresponding to different detector depths based on the receiving channels of the front and rear guns located at the same position. The first calculation module is used to calculate the centroid frequency and variance of the first arrival wave in the corrected seismic waves corresponding to different detector depths, and to correct the centroid frequency and variance of the first arrival wave based on the relationship model between the centroid frequency and variance of the first arrival wave and the receiving depth. The second calculation module is used to calculate the Q value corresponding to each receiving channel based on the centroid frequency and variance of the first arrival wave of each receiving channel at different detector depths that have been calibrated. According to the matching relationship between the numbered geophone positions and the firing blasts, during each firing at a preset distance from the wellhead, the geophone string at the multiple geophone positions corresponding to the firing blast is used as a receiving channel to collect the seismic waves received by the geophone string, including: The first step is that when the Nth shot is fired, the geophone in the well is placed at the well section position corresponding to the geophone points numbered (i-1)×(N-1)+1 to (i-1)×(N-1)+i, where i is the number of receiving channels corresponding to each firing shot, and N is the number of shots. The second step is to raise the geophone to a distance of i-1 times the track spacing after the Nth shot acquisition is completed, and then perform the N+1th shot acquisition. The geophone in the well is placed at the well section position corresponding to the geophone points numbered (i-1)×(N-1)+i to (i-1)×N+i to receive the data. The third step is to collect data in sequence according to the first and second steps until the data collection of the entire well section is completed. The model relating the centroid frequency and variance of the first arrival wave to the receiving depth corrects the centroid frequency and variance of the first arrival wave, including: Based on the Laida criterion, outliers in the model relating the centroid frequency of the first arrival wave to the receiving depth are eliminated. Based on the relationship model between the centroid frequency of the first arrival wave after removing outliers and the receiving depth, the centroid frequency of the first arrival wave of each receiving channel is calculated according to the receiving depth. Based on the Laida criterion, outliers in the model relating the centroid variance of the first arrival wave to the receiving depth are removed. Based on the relationship model between the centroid variance of the first arrival wave after outlier removal and the receiving depth, the centroid variance of the first arrival wave for each receiving channel is calculated according to the receiving depth.

7. An electronic device, characterized in that, It includes a processor, a communication interface, a memory, and a communication bus, wherein the processor, the communication interface, and the memory communicate with each other through the communication bus; Memory, used to store computer programs; A processor, when executing a program stored in memory, implements the method for calculating the quality factor Q value as described in any one of claims 1-5.

8. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the method for calculating the quality factor Q value as described in any one of claims 1-5.

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