A method, readable storage medium, and device for inverting water hammer wave velocity based on fracturing

Abstract

This application discloses a method, readable storage medium, and device for inverting water hammer wave velocity based on fracturing, belonging to the field of fracturing technology. The method includes: acquiring the raw signal of water hammer pressure; performing noise reduction processing to obtain a noise-reduced signal; converting the noise-reduced signal to the cepstrum domain; establishing the relationship between the cepstrum amplitude and the fluid injection response time, generating a two-dimensional curve, identifying peak points, and obtaining the corresponding fluid injection response time; designing the value of the water hammer wave velocity and converting it to obtain the fluid injection depth value; and solving for the minimum value of the sum of the differences between the fluid injection depth value and the designed depth value. The readable storage medium stores the above method; the device has a computer program that stores and executes the above method. This application can effectively determine the water hammer wave velocity when the bridge plug slips and the actual bridge plug position does not match the designed bridge plug position, thus promoting a better match between the fracturing fluid injection position and the designed perforation position, thereby guiding the identification of the fracturing injection point, optimizing the fracturing construction plan, and improving the fracturing stimulation effect.

Description

Technical Field

[0001] This application belongs to the field of fracturing technology, and in particular relates to a water hammer wave velocity inversion method, readable storage medium and device based on fracturing. Background Technology

[0002] my country possesses abundant shale gas resources with broad development prospects. Due to the extremely dense nature of these reservoirs, effective development requires staged, multi-cluster fracturing techniques. In recent years, the method of using water hammer analysis to locate fracturing inlet points has attracted widespread attention due to its advantages of low cost and ease of operation. Accurate estimation of water hammer velocity is crucial for identifying fracturing inlet points. Accurate estimation of water hammer velocity can effectively improve the accuracy of fracturing fluid inlet point location identification, thereby providing a scientific basis for optimizing fracturing operation schemes and improving fracturing stimulation effects.

[0003] However, existing water hammer velocity analysis methods, such as the periodic method, the half-period method, and the Fourier fundamental frequency method, calculate water hammer velocity based on the bridge plug. These methods are only applicable to situations where there is no casing damage or bridge plug slippage during construction. When bridge plug slippage occurs, the actual bridge plug position differs significantly from the designed position. Therefore, establishing a method for determining water hammer velocity under abnormal conditions such as bridge plug slippage is of significant engineering guiding importance for identifying fracturing inlet locations and optimizing fracturing construction methods. Summary of the Invention

[0004] This application aims to solve the technical problem that existing analysis methods cannot be used to determine the water hammer velocity when the bridge plug slips. To this end, this application provides a water hammer velocity inversion method, readable storage medium and device based on fracturing. It can effectively determine the water hammer velocity when the actual bridge plug position does not match the designed bridge plug position due to bridge plug slippage. This promotes a better match between the fracturing fluid inlet position and the designed perforation position, thereby guiding the identification of the fracturing inlet point, optimizing the fracturing construction plan and improving the fracturing effect.

[0005] In a first aspect, embodiments of this application provide a water hammer wave velocity inversion method based on fracturing, which includes:

[0006] The raw signal of water hammer pressure downhole was collected at the wellhead when the pump was stopped;

[0007] The original signal is denoised to obtain the denoised signal of water hammer pressure;

[0008] The noise-reducing signal is converted to the cepstral domain using the cepstral transformation formula;

[0009] Establish a functional relationship between cepstrum amplitude and liquid inlet response time in the cepstrum domain, and generate a two-dimensional curve of the two.

[0010] Identify the maximum peak point in the two-dimensional curve and obtain the liquid inlet response time corresponding to the peak point;

[0011] Based on the fluid injection response time and the designed fracturing perforation range, a set of water hammer wave velocity values ​​were designed, and the conversion between water hammer wave velocity, time and depth was performed to obtain a set of fluid injection depth values.

[0012] Find the minimum sum of the differences between a set of inlet depth values ​​and the designed depth values ​​to obtain the actual water hammer wave velocity.

[0013] In some implementations, the cepstral transformation formula is used to transform the noise-reduced signal to the cepstral domain. Specifically, the logarithm of the noise-reduced signal is taken and an inverse Fourier transform is performed.

[0014] In some implementations, the cepstral conversion formula is:

[0015] ;

[0016] in, It is the cepstral function; x ( t () represents the original signal; i The imaginary unit; ω ω is the angular frequency, expressed in radians per second (rad / s). t For time, s; τ The frequency is the inverse frequency, s.

[0017] In some implementations, the sum of the differences between a set of inlet depth values ​​and the designed depth values ​​is specifically calculated as follows:

[0018] ;

[0019] in, E s Let m be the sum of the differences. L d To design the depth of the perforation cluster, m; L k The depth of liquid entry is given in meters for different inverse frequency response times and different wave velocities.

[0020] In some implementations, the conversion between time and depth is performed using the following formula:

[0021] ;

[0022] in, L k The ingress depth values ​​(m) are for different inverse frequency response times and different wave velocities. a s The water hammer wave velocity is given in m / s for different values. T zLet be the different liquid inlet response times in the ceccentric frequency domain, s.

[0023] In some implementations, a functional relationship between cepstrum amplitude and liquid inlet response time is established in the cepstrum domain. Specifically, in the cepstrum domain, the sampling points at different cepstrum response times are multiplied by cepstrum vectors and then superimposed to obtain the functional relationship between cepstrum response time and cepstrum amplitude.

[0024] In some implementations, when acquiring the raw signal of downhole water hammer pressure at the wellhead, the acquisition frequency is [900Hz, 1100Hz].

[0025] In some implementations, a Butterworth low-pass filter is used when denoising the original signal.

[0026] Secondly, embodiments of this application provide a readable storage medium storing a terminal program, characterized in that, when the terminal program is executed, it performs the water hammer wave velocity inversion method based on fracturing as described in any one of claims 1-8.

[0027] Thirdly, embodiments of this application provide an apparatus for inverting water hammer wave velocity, including a memory, a processor, and a computer program stored in the memory and executable in the processor, characterized in that the computer program includes steps corresponding to the water hammer wave velocity inversion method based on fracturing as described in any one of claims 1-8.

[0028] As can be seen from the above technical solution, the beneficial effects of this application are as follows:

[0029] 1. The method of this application avoids the calculation process introduced by bridge plug slippage and adopts an alternative calculation method. Specifically, it collects the original signal of water hammer pressure, effectively filters out noise through noise reduction to reduce the interference of noise signals on the water hammer pressure signal, and uses the cepstrum conversion formula to convert the noise-reduced signal to the cepstrum domain. Since the impedance of the wellbore and the impedance of the fracture will have significantly different characteristics in the cepstrum domain, the signal characteristics at the fluid inlet can be effectively extracted. By establishing the relationship between the cepstrum amplitude and the fluid inlet response time and generating a graph, the characteristic points of the fluid inlet response can be intuitively displayed and identified in the graph. Identifying the peak point can find the corresponding fluid inlet response time. With the fluid inlet cluster as a constraint, the water hammer wave velocity is designed by the fluid inlet response time and the perforation range. Then, the fluid inlet depth value is obtained by introducing time parameters and converting. Then, the minimum error method is used to match the fluid inlet depth calculated under different wave velocities with the designed fracturing cluster, and then the water hammer wave velocity is obtained by inversion. This application can effectively determine the water hammer wave velocity when the bridge plug slips and the actual bridge plug position does not match the designed bridge plug position, so as to better match the fracturing fluid inlet position with the designed perforation position, thereby guiding the identification of fracturing fluid inlet point, optimizing fracturing construction plan, and improving fracturing transformation effect.

[0030] 2. The storage medium of this application provides a storage medium by applying the water hammer wave velocity inversion method based on fracturing in a storage medium, which can be applied to a variety of electronic devices, thereby enabling rapid determination of water hammer wave velocity when the actual bridge plug position differs significantly from the designed bridge plug position during bridge plug slippage.

[0031] 3. The device of this application contains the above-mentioned water hammer wave velocity inversion method based on fracturing as a computer program. The execution process of the computer program is stored in the memory. By executing the computer program through the processor, the water hammer wave velocity can be obtained quickly and the result can be output. This simplifies the calculation of water hammer wave velocity during bridge plug slippage, improves efficiency, and enables the rapid determination of water hammer wave velocity. This helps to quickly provide feedback on the fracturing construction simulation results and adjust and optimize the fracturing construction plan. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced one by one below. Obviously, the accompanying drawings described below are some embodiments of this application. For those skilled in the art, other embodiments and drawings can be obtained based on these drawings without creative effort. Various schematic diagrams according to the embodiments of this application are shown in the drawings. These drawings are not necessarily drawn to scale. For the purpose of clear expression, some details are enlarged and some details may be omitted. The shapes of various regions and layers shown in the figures, as well as their relative sizes and positional relationships, are only exemplary. In reality, there may be deviations due to manufacturing tolerances or technical limitations. Except as specifically specified or limited in this application, those skilled in the art can design embodiments with different shapes, sizes, and relative positions according to actual needs.

[0033] The flowcharts shown in the accompanying drawings are merely illustrative and do not necessarily include all content and operations / steps, nor do they necessarily have to be performed in the described order. For example, some operations / steps can be broken down, while others can be combined or partially combined; therefore, the actual execution order may change depending on the specific circumstances.

[0034] Figure 1 A schematic diagram illustrating the steps of an embodiment of the water hammer wave velocity inversion method based on fracturing according to the present invention is shown.

[0035] Figure 2 A schematic diagram of the original signal of water hammer pressure in the water hammer wave velocity inversion method based on fracturing of the present invention is shown.

[0036] Figure 3 The cepstrum diagram of the noise-reduced signal of the water hammer wave velocity of the present invention is shown. Detailed Implementation

[0037] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. The detailed description of the embodiments of this application provided in the drawings is not intended to limit the scope of the claimed application. The described embodiments are only a part of the embodiments of this application, not all of them. Based on the embodiments in this application, they can be arranged and designed in various different configurations. All other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0038] This application is described below with reference to the accompanying drawings and specific embodiments:

[0039] Please refer to Figure 1 The first aspect of this application provides a method for inverting water hammer wave velocity based on fracturing, comprising:

[0040] S1. Collect the raw water hammer pressure signal at the wellhead when the pump is shut down. First, install a pressure monitoring gauge at the wellhead. The acquisition frequency is determined as needed. The pressure monitoring gauge collects and records the water hammer pressure signal generated during the fracturing pump shutdown period in real time. The raw water hammer pressure signal includes downhole information such as the location of the fracturing fluid inlet point, bridge plug slippage, and bridge plug leakage, providing a data basis for subsequent analysis.

[0041] S2. Denoising the original signal to obtain the denoised signal of the water hammer pressure. The original signal consists of two parts: a useful signal and a noise signal. The useful signal usually carries information such as the location of the downhole fracturing fluid inlet point, bridge plug slippage, and bridge plug leakage, and is the main object of subsequent interpretation. The noise signal is interference introduced during signal acquisition, transmission, and processing. Excessive noise can affect the analysis of the useful signal. Denoising can be achieved by using various filtering methods to process the original signal, such as low-pass filtering, high-pass filtering, band-pass filtering, and band-stop filtering. Filters that can be used include Butterworth filters, Chebyshev filters, or Bessel filters.

[0042] S3. Use the cepstral conversion formula to convert the denoised signal to the cepstral domain. This makes it easier to identify the response characteristics of fracturing fluid injection in the cepstral domain. The cepstral conversion formula is the key to performing the conversion. After the denoised signal is converted, the water hammer pressure signal in the cepstral domain is obtained. In the cepstral domain, the signal characteristics reflected from the wellbore and the signal characteristics reflected from the fluid injection point are significantly different, which can quickly identify the response characteristics of fracturing fluid injection.

[0043] S4. Establish a functional relationship between the cepstral amplitude and the inlet response time in the cepstral domain, and generate a two-dimensional curve of the two. By establishing a functional relationship in the cepstral domain and converting it into a curve, it is easy to find the difference in water hammer pressure signal at different inlet response times.

[0044] S5. Identify the maximum peak point in the two-dimensional curve and obtain the corresponding liquid inlet response time. The maximum peak point refers to the peak point whose amplitude is significantly higher than other amplitudes. It is the maximum value point. For example, if the peak value of a certain cepstrum amplitude of the water hammer pressure signal is much higher than the baseline or the adjacent value, it is defined as the maximum peak point. After determining the peak point, the point corresponding to the peak point on the time axis is the liquid inlet response time in the cepstrum domain.

[0045] S6. Based on the fluid injection response time and the designed fracturing perforation range, design a set of water hammer wave velocity values, and perform a conversion between water hammer wave velocity, time, and depth to obtain a set of fluid injection depth values. Based on the boundary values ​​of the perforation range, deduce the theoretical boundary of the water hammer wave velocity. Generate a wave velocity sequence within the water hammer wave velocity range using an arithmetic progression. Map the wave velocity sequence and the fluid injection response time to a fluid injection depth sequence using a conversion formula.

[0046] S7. Find the minimum sum of the differences between a set of inlet depth values ​​and the designed depth values ​​to obtain the actual water hammer wave velocity. Using the minimum error method, match the calculated inlet point position under different wave velocities with the designed perforation position to calculate the water hammer wave velocity.

[0047] Existing methods for analyzing water hammer velocity, such as the periodic method, half-period method, and Fourier fundamental frequency method, calculate water hammer velocity based on the bridge plug. These methods are only applicable to situations where there is no casing damage or bridge plug slippage during construction. When bridge plug slippage occurs, the actual bridge plug position differs significantly from the designed bridge plug position. This is because if the designed bridge plug position is still used as the benchmark to calculate the water hammer velocity and determine the inlet point, the calculated inlet position will differ significantly from the designed inlet position during fracturing. Consequently, there is a lack of existing methods for analyzing water hammer velocity under abnormal conditions such as bridge plug slippage. This application avoids the calculation process introduced by bridge plug slippage by adopting an alternative calculation method. Specifically, it collects the original signal of water hammer pressure, effectively filters out noise through noise reduction to reduce the interference of noise signals on the water hammer pressure signal, and uses the cepstrum conversion formula to convert the noise-reduced signal to the cepstrum domain. Since the impedance of the wellbore and the impedance of the fracture will have significantly different characteristics in the cepstrum domain, the signal characteristics at the fluid inlet can be effectively extracted. By establishing the relationship between the cepstrum amplitude and the fluid inlet response time and generating a graph, the characteristic points of the fluid inlet response can be intuitively displayed and identified in the graph. Identifying the peak points can help find the corresponding fluid inlet response time. With the fluid inlet cluster as a constraint, the water hammer wave velocity is designed by the fluid inlet response time and the perforation range. Then, by introducing time parameters, the fluid inlet depth value is calculated and converted. Then, using the minimum error method, the fluid inlet depth calculated under different wave velocities is matched with the designed fracturing cluster, and then the water hammer wave velocity is obtained by inversion. This application can effectively determine the water hammer wave velocity when the bridge plug slips and the actual bridge plug position does not match the designed bridge plug position, so as to better match the fracturing fluid inlet position with the designed perforation position, thereby guiding the identification of fracturing fluid inlet point, optimizing fracturing construction plan, and improving fracturing transformation effect.

[0048] In some implementations, the original signal expression acquired at the wellhead in step S2 is as follows:

[0049]

[0050] In the formula: y ( t () represents the water hammer pressure signal collected at the wellhead, in MPa; x ( t () represents the useful water hammer pressure signal, in MPa; e ( t () represents the noise pressure signal, in MPa.

[0051] In some implementations, a Butterworth low-pass filter is used when denoising the original signal. A large amount of noise can mask the characteristics of the useful signal; therefore, the original signal based on the acquired water hammer pressure is denoised using a Butterworth low-pass filter to filter out high-frequency noise, thereby minimizing the interference of noise signals on the useful signal.

[0052] Butterworth low-pass filters utilize their maximally flat amplitude-frequency response, meaning that signals of all frequencies within the passband can pass through the filter with almost the same amplitude, without significant amplitude variations or distortion. This flatness helps maintain the integrity of the useful signal, ensuring that the waveform of the filtered useful signal is as close as possible to the original signal. Through its maximally flat amplitude-frequency response, the Butterworth filter not only preserves the amplitude characteristics of the original signal but also exhibits good linearity in its phase characteristics, solving the phase nonlinearity distortion problem present in traditional filters. Therefore, noise reduction is achieved while maintaining the integrity of the original useful signal. The amplitude-frequency response of the Butterworth low-pass filter can be expressed by the following equation:

[0053]

[0054] In the formula: H (jω) This indicates the frequency response of the filter, that is, the degree to which the filter amplifies or attenuates signals of different frequencies; ε It is a parameter related to passband ripple, used to control the maximum gain deviation within the passband, and is dimensionless; ω ω is the angular frequency, expressed in radians per second (rad / s). ω c ω is the cutoff angular frequency, in radians per second (rad / s). n Let be the order of the filter, which is dimensionless.

[0055] In some implementations, the cepstral transformation formula is used to convert the denoised signal to the cepstral domain. Specifically, the logarithm of the denoised signal is taken, and an inverse Fourier transform is performed. Since the impedance of the wellbore is positive and the impedance of the fracture is negative, based on this characteristic, the filtered time-domain water hammer signal is mapped to the cepstral domain using cepstral analysis technology. In the cepstral domain, the signal characteristics reflected through the wellbore and the signal characteristics reflected by the fracture can be distinguished, the periodic characteristics of the signal can be identified, and thus the fluid injection response characteristics of each fracturing cluster can be effectively identified.

[0056] In some implementations, the logarithm of the noise-reduced signal is taken and an inverse Fourier transform is performed, specifically calculated using the cepstral transform formula, which is:

[0057]

[0058] in, It is the cepstral function; x ( t () represents the original signal; i The imaginary unit; ω ω is the angular frequency, expressed in radians per second (rad / s). t For time, s; τ The frequency is the inverse frequency, s.

[0059] In some implementations, a functional relationship between cepstral amplitude and liquid inlet response time is established in the cepstral domain. Specifically, in the cepstral domain, sampling points with different cepstral response times are multiplied by their cepstral vectors and then superimposed to obtain the functional relationship between cepstral response time and cepstral amplitude. Based on the identified cepstral response characteristics, manually extracting the range and simply using the average cepstral response time method to obtain the cepstral response time can easily produce large errors. Therefore, a functional relationship between cepstral amplitude and liquid inlet response time is established, generating a two-dimensional curve of cepstral amplitude and cepstral response time. The peak point with the largest amplitude in the curve is identified and recorded as the strong peak point. The cepstral response time corresponding to the strong peak point is the liquid inlet response time.

[0060] Specifically, the sampling points at different physical times are multiplied by a vector, as shown in the following formula:

[0061]

[0062] in, F mnσ This represents the cepstral amplitude vector function at different physical times; m , n For different physical time locations; V tm，σ For physical time t m The cepstral amplitude vector below; V tn，σFor physical time t n The cepstral amplitude vector below; parameters σ It characterizes the centroid position of each vector in the cepstrum domain during reflection.

[0063] The vector products of relevant sampling point pairs are superimposed to construct the functional relationship between cepstral response time and cepstral amplitude. A graph of cepstral amplitude versus response time is plotted, and the liquid inlet response time is determined by the strong peak points in the graph. The formula is as follows:

[0064]

[0065] in, F σ This is a function for superimposing cepstral amplitude vectors at different physical times; F mnσ This represents the cepstral amplitude vector function at different physical times; m , n For different physical time locations; V tm，σ For physical time t m The cepstral amplitude vector below; V tn，σ For physical time t n The cepstral amplitude vector below; parameters σ It characterizes the centroid position of each vector in the cepstrum domain during reflection.

[0066] Using the determined fluid injection response time, and combined with the designed perforation range, a series of water hammer wave velocities are designed according to a gradient, i.e., a series of water hammer wave velocities that increase at a certain gradient. In this way, the position of the designed perforation cluster is used as a constraint to determine the water hammer wave velocity. Then, the water hammer wave velocity, time and depth are converted, and the obtained series of fluid injection depth values ​​are compared with the design depth values. When the error is minimized, the wave velocity at this time is considered to be the actual water hammer wave velocity under the well conditions.

[0067] In some implementations, the sum of the differences between a set of inlet depth values ​​and the designed depth values ​​is specifically calculated as follows:

[0068]

[0069] in, E s Let m be the sum of the differences. L d To design the depth of the perforation cluster, m; L k The depth of liquid entry is given in meters for different inverse frequency response times and different wave velocities.

[0070] In some implementations, the conversion between time and depth is performed using the following formula:

[0071]

[0072] in, L k The ingress depth values ​​(m) are for different inverse frequency response times and different wave velocities. a s The water hammer wave velocity is given in m / s for different values. T z Let be the different liquid inlet response times in the ceccentric frequency domain, s.

[0073] In some implementations, when collecting the raw signal of downhole water hammer pressure at the wellhead, the sampling frequency is [900Hz, 1100Hz], such as 900Hz, 1000Hz or 1100Hz. Before sampling, a high-frequency pressure monitoring meter is installed at the wellhead. A sampling frequency of 1000Hz is more suitable. If the sampling frequency is insufficient, it will be difficult to monitor the complete water hammer waveform, thus affecting subsequent analysis.

[0074] An example using the method of this application is given, based on water hammer signal data collected from the 14th section of a shale gas fracturing well in the Sichuan Basin. The water hammer wave velocity of this section is analyzed, and the original water hammer pressure is shown in [reference needed]. Figure 2 The well was designed with 9 perforations, ranging from 4082.35 m to 4153.35 m. A significant pressure drop was observed in the fracturing operation curve for this section, suggesting bridge plug slippage. The water hammer signal for this section was filtered, and then mapped to the cepstrum domain. The cepstrum analysis diagram is shown below. Figure 3 , Figure 3 The continuous blue area within the red box represents the fluid inlet response, while the highlighted yellow area represents the wellbore response. The inverted frequency response shows a fluid inlet response time range of 0.2s. Typically, a perforation range of approximately 70m should only show an inverted frequency response time range of 0.1s. The inverted frequency domain plot of the water hammer pressure curve in this segment shows two segments of fluid inlet characteristic response, and there is no highlighted area response with bridge plug intervals in the response range. The inverted frequency domain plot analysis also indicates that bridge plug slippage occurs in this segment. Using the method of this invention, the water hammer wave velocity of this section is inverted using cepstral analysis. The cepstral analysis shows that the peak liquid inlet response time ranges from 5.185 s to 5.375 s. Combined with the perforation range, the designed wave velocity range is 1574.67 m / s to 1578.92 m / s. The obtained series of liquid inlet depth values ​​are compared with the designed depth values. When the wave velocity is 1575.37 m / s, the calculated liquid inlet position matches the designed perforation position well, achieving the minimum error. This value is the wave velocity value inverted using the cepstral analysis method for this section.

[0075] A second aspect of this application provides a readable storage medium storing a terminal program. The terminal program, when executed, performs the water hammer wave velocity inversion method based on fracturing as described above. If the modules / units integrated into the terminal device are implemented as software functional units and sold or used as independent products, the terminal program can be stored in a readable storage medium. Based on this understanding, all or part of the processes of the methods described in the above embodiments can also be implemented by the terminal program instructing related hardware. The terminal program can be stored in a readable storage medium. When the terminal program is executed by a processor, it can implement the steps of each method in the above embodiments. When the terminal program is executed by the processor, the specific implementation of each step and the resulting technical effects are the same as in the aforementioned method embodiments. For brevity, any parts not mentioned in this embodiment can be referred to the corresponding content in the aforementioned method embodiments. The readable storage medium includes hard disks, memory, optical storage, pluggable hard disks, memory cards, secure digital cards, flash memory cards, or at least one disk storage device, flash memory device, or other volatile solid-state storage device.

[0076] The storage medium of this application provides a storage medium by applying a fracturing-based water hammer wave velocity inversion method in the storage medium. This allows it to be applied to various electronic devices, thereby enabling rapid determination of water hammer wave velocity when the actual bridge plug position differs significantly from the designed bridge plug position during bridge plug slippage.

[0077] A third aspect of this application provides an apparatus for water hammer wave velocity inversion, including a memory, a processor, and a computer program stored in the memory and executable in the processor. The computer program includes steps corresponding to the water hammer wave velocity inversion method based on fracturing described above. When the processor executes the computer program, it implements the steps in the above-described method embodiments; or, when the processor executes the computer program, it implements the functions of each module / unit in the embodiments of the fracturing fracture diagnosis method and apparatus described above. It should be understood that the apparatuses of various embodiments of this application can be implemented based on a memory and a processor. Each memory is used to store a computer program for executing the methods described above, and the processor executes the computer program, causing the fracturing fracture diagnosis method and apparatus to implement the methods of the various embodiments described above.

[0078] The device of this application exists as a computer program for the above-mentioned water hammer wave velocity inversion method based on fracturing. The execution process of the computer program is stored in the memory. By executing the computer program through the processor, the water hammer wave velocity can be obtained quickly and the result can be output. This simplifies the calculation of water hammer wave velocity during bridge plug slippage, improves efficiency, and enables the rapid determination of water hammer wave velocity. This helps to quickly provide feedback on the fracturing construction simulation results and adjust and optimize the fracturing construction plan.

[0079] Regarding the specific implementation methods of this application, it should be noted that:

[0080] In the description of this application, the terms "comprising," "including," or any other variations thereof are intended to cover a 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 that are consistent with the concept of this application, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other elements in the process, method, article, or apparatus that includes said element.

[0081] In the description of this application, the use of terms such as "some embodiments," "optional embodiments," "example," "specific example," "optional example," or "optional embodiment," etc., indicates that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application, but does not imply that these embodiments illustrate and describe all possible forms of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Furthermore, those skilled in the art can combine and integrate the different embodiments or examples described in this specification.

[0082] The present invention has been described in detail above with reference to specific embodiments and exemplary examples. The above description is exemplary and not exhaustive, and is not limited to the disclosed embodiments; the above description should not be construed as a limitation of the present invention. Technical solutions between various embodiments can be combined with each other, but must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed in this application. Although embodiments of the present application have been shown and described, various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present application. Those skilled in the art will understand that various other specific changes and combinations of embodiments based on the technical teachings disclosed in this application, without departing from the essence of the present application, are still within the scope of protection defined by the claims of the present invention and their equivalent technical solutions.

Claims

1. A fracturing-based water hammer wave velocity inversion method, characterized in that, The method comprises the following steps: collecting the original signal of the water hammer pressure in the well under the condition of pump stopping at the wellhead; performing noise reduction processing on the original signal to obtain a noise-reduced signal of the water hammer pressure; converting the noise-reduced signal to the cepstrum domain by using a cepstrum conversion formula; establishing a functional relationship between the cepstrum amplitude and the liquid inlet response time in the cepstrum domain, and generating a two-dimensional curve graph of the two; identifying the maximum peak point in the two-dimensional curve graph to obtain the liquid inlet response time corresponding to the peak point; designing a group of water hammer wave speed values based on the liquid inlet response time and the designed fracturing perforation range, and converting the water hammer wave speed, time and depth to obtain a group of liquid inlet depth values; solving the minimum value of the sum of differences between the group of liquid inlet depth values and the designed depth values to obtain the actual water hammer wave speed.

2. The frac-based water hammer wave speed inversion method of claim 1, wherein, The conversion of the noise-reduced signal to the cepstrum domain by using the cepstrum conversion formula is specifically: taking the logarithm of the noise-reduced signal and performing inverse Fourier transform.

3. The frac-based water hammer wave speed inversion method of claim 2, wherein, The cepstrum conversion formula is: ； in, It is the cepstral function; x ( t () represents the original signal; i The imaginary unit; The sum of differences between the group of liquid inlet depth values and the designed depth values is specifically calculated as: ω is the angular frequency, expressed in radians per second (rad / s). t For time, s; The conversion of the time and the depth is specifically as follows: The frequency is the inverse frequency, s.

4. The frac-based water hammer wave speed inversion method of claim 1, wherein, The functional relationship between the cepstrum amplitude and the liquid inlet response time in the cepstrum domain is specifically: in the cepstrum domain, the sampling points under different cepstrum response times are multiplied by the cepstrum vector product, and then superimposed to obtain the functional relationship between the cepstrum response time and the cepstrum amplitude. ； wherein, E s is the difference sum, m; L d is the design perforation cluster depth, m; L k is the liquid depth value under different inverse frequency response time and different wave velocity, m.

5. The frac-based water hammer wave speed inversion method of claim 4, wherein, When collecting the original signal of the water hammer pressure in the well, the collection frequency is [900Hz, 1100Hz]. ； wherein, L k is the liquid inlet depth value under different reverse frequency response time and different wave speed, m; a s is the water hammer wave speed under different values, m / s; T z is the different liquid inlet response time in the reverse frequency domain, s.

6. The frac-based water hammer wave speed inversion method of claim 1, wherein, When performing noise reduction processing on the original signal, a Butterworth low-pass filter is used.

7. The fracture-based water hammer wave velocity inversion method according to any one of claims 1-6, wherein, The terminal program performs the fracturing-based water hammer wave speed inversion method according to any one of claims 1-8 when executed.

8. The fracture-based water hammer wave velocity inversion method according to any one of claims 1-6, wherein, The computer program comprises steps corresponding to the fracturing-based water hammer wave speed inversion method according to any one of claims 1-8.

9. A readable storage medium, the readable storage medium storing a terminal program, characterized in that, ​ 10. An apparatus for water hammer wave velocity inversion, comprising a memory, a processor, and a computer program stored in the memory and executable in the processor, characterized in that, ​

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