Method, system, and apparatus for calculating absorption attenuation under well-logging spectral constraints

Abstract

The application provides a well logging spectrum constrained absorption attenuation calculation method, system and device, and belongs to the technical field of oil and gas exploration. The absorption attenuation calculation method comprises the following steps: obtaining high-frequency band seismic data after high-resolution processing; determining an absorption coefficient processing range based on a target layer horizon; calculating a seismic amplitude spectrum based on the seismic data, and calculating a well logging amplitude spectrum based on well logging data; performing spatial interpolation on the well logging amplitude spectrum to obtain a three-dimensional well logging spectrum data body corresponding to the seismic amplitude spectrum; calibrating the seismic amplitude spectrum based on the well logging amplitude spectrum as a standard; and calculating an absorption coefficient by using a bispectrum absorption coefficient calculation formula and drawing an absorption coefficient plan. The application can solve the problems of low resolution and low accuracy of the existing absorption coefficient method, adds well logging spectrum constraint, and calculates the absorption coefficient together with the seismic spectrum, so that the calculation result is closer to the actual result.

Description

Technical Field

[0001] This invention relates to the field of seismic interpretation technology for oil and gas field exploration. Specifically, it relates to a method for calculating absorption attenuation under well logging spectrum constraints, a system for calculating absorption attenuation under well logging spectrum constraints, and a computer device and computer-readable storage medium for implementing the method for calculating absorption attenuation under well logging spectrum constraints. Background Technology

[0002] Absorption attenuation is a crucial aspect of seismic exploration and development in oil and gas. It primarily utilizes the energy absorption and attenuation of seismic waves during propagation within rock formations and fluids to predict fluid-bearing conditions. Many traditional fluid prediction methods exist, especially gas-water prediction methods, including seismic wave properties, pattern recognition, absorption coefficients, and fluid sensitivity factors. The absorption coefficient, similar to this method, has clear geological and geophysical significance and is a commonly used and intuitive method for reflecting fluid conditions. Its basic idea is to calculate the magnitude of absorption attenuation based on the changes in the amplitude of various frequency components at different times. Most fluid prediction methods calculate directly or indirectly from seismic data based on absorption principles, each with its own advantages and disadvantages. The calculation of the absorption coefficient suffers from low resolution and unstable results, thus its usage is not widespread. This is mainly due to the low frequency and narrow bandwidth of conventional seismic data, as well as the impact of absorption compensation processing on absorption attenuation characteristics. Since absorption attenuation is generally most pronounced in the high-frequency range, calculating the absorption coefficient at higher frequencies should yield better results and improve the method's practicality.

[0003] The existing calculation of absorption coefficients suffers from problems such as low resolution and low accuracy. The main reason is that the absorption attenuation characteristics are more fully realized in the high-frequency band, while conventional seismic data has a lower frequency and narrower bandwidth. In addition, the absorption compensation process may affect the absorption attenuation characteristics and introduce errors.

[0004] This invention, through extended research using high-resolution technology, has discovered new patterns and developed a method for calculating absorption attenuation under logging spectrum constraints.

[0005] Currently, theoretical research on the calculation of absorption coefficients constrained by well logging spectra is lacking. For example, patent document CN104536042A, published on April 22, 2015, entitled "A Method and Apparatus for Amplitude Compensation of Two-Dimensional Post-Stack Seismic Data," describes a method for amplitude compensation of two-dimensional post-stack seismic data. This method utilizes amplitude compensation factors within the effective frequency band of the seismic data and the boundaries of amplitude-weakened regions in the two-dimensional post-stack seismic data to perform amplitude compensation. Patent document CN107390271A, published on November 24, 2017, entitled "A Method and Apparatus for Amplitude Compensation of Seismic Data," describes a method for amplitude compensation of seismic data. This method uses a velocity-controlled geometric diffusion compensation method to obtain the longitudinal compensation amount and then performs amplitude compensation. Both of the above methods achieve the purpose of exploration by processing and correcting the original seismic data. However, conventional seismic data has low resolution and inconspicuous absorption characteristics. In addition, due to the changes in absorption compensation, the prediction effect of conventional absorption coefficient calculation is not ideal. At the same time, the scope of application is small, the resolution of the earthquake is not improved, the absorption attenuation characteristics cannot be applied, and the high-frequency components of the seismic wave cannot be well utilized. Summary of the Invention

[0006] The purpose of this invention is to address at least one of the aforementioned shortcomings of the prior art. For example, this invention provides a method, system, and device for calculating absorption attenuation under well logging spectrum constraints, to overcome the problems of low resolution and low accuracy in conventional absorption coefficient methods.

[0007] To achieve the above objectives, this invention provides a method for calculating absorption attenuation under well logging spectrum constraints. The method includes the following steps: obtaining high-resolution processed high-frequency seismic data; determining the absorption coefficient processing range based on the target layer; calculating the seismic amplitude spectrum based on the seismic data and the well logging amplitude spectrum based on the well logging data; performing spatial interpolation on the well logging amplitude spectrum to obtain a three-dimensional well logging spectrum data volume corresponding to the seismic amplitude spectrum; calibrating the seismic amplitude spectrum using the well logging amplitude spectrum as a standard; and calculating the absorption coefficient using a dual-spectrum absorption coefficient calculation formula, wherein the formula is:

[0008]

[0009] Where α is the absorption coefficient, dimensionless; f is the frequency, in Hz; f s f is the starting frequency, in Hz; e The termination frequency is in Hz; A w (f) represents the amplitude of the logging amplitude spectrum, which is dimensionless; A s (f) represents the amplitude of the earthquake amplitude spectrum, which is dimensionless; N f The frequency number of the amplitude spectrum is dimensionless.

[0010] In an exemplary embodiment of the absorption attenuation calculation method under logging spectrum constraints of the present invention, the absorption attenuation calculation method may include: performing high-resolution processing on pre-stack seismic data to obtain pre-stack high-frequency seismic data, and / or performing high-resolution processing on post-stack seismic data to obtain post-stack high-frequency seismic data.

[0011] In an exemplary embodiment of the absorption attenuation calculation method under logging spectrum constraints of the present invention, the absorption attenuation calculation method may further include: determining the absorption coefficient processing range based on the target layer position and time window size.

[0012] In an exemplary embodiment of the absorption attenuation calculation method under the constraint of well logging spectrum of the present invention, the method for calibrating the seismic amplitude spectrum can be as follows: average the well logging amplitude spectra of all wells and fit them into a straight line, then sum and average the seismic amplitude spectra of each well and fit them into a straight line, and calculate the amplitude ratio of the frequencies corresponding to the two straight lines as the calibration coefficient to calibrate the seismic spectrum.

[0013] In an exemplary embodiment of the absorption attenuation calculation method under logging spectrum constraints of the present invention, the inverse distance weighted interpolation method or the Kriging interpolation method can be used to spatially interpolate the logging amplitude spectrum.

[0014] In an exemplary embodiment of the absorption attenuation calculation method under the constraint of well logging spectrum of the present invention, the absorption attenuation calculation method further includes: drawing an absorption coefficient plane diagram based on the absorption coefficient calculation results.

[0015] In an exemplary embodiment of the absorption attenuation calculation method under the logging spectrum constraint of the present invention, the logging data may include an acoustic curve, or may include an acoustic curve and a density curve.

[0016] In an exemplary embodiment of the absorption attenuation calculation method under the logging spectrum constraint of the present invention, the dominant frequency of the high-frequency seismic data is above 50 Hz and the bandwidth is above 100 Hz.

[0017] Another aspect of the present invention provides a method for predicting the fluid content of rock strata, which uses the absorption attenuation calculation method described in any one of the above to determine the absorption coefficient of the target layer, and based on the magnitude of the absorption coefficient, finds the gas-bearing distribution area and predicts the gas-water distribution.

[0018] Another aspect of the present invention provides an absorption attenuation calculation system under logging spectrum constraints. The system may include a data processing module, a processing range module, an amplitude spectrum calibration module, and an absorption coefficient calculation module.

[0019] The data processing module is configured to perform high-resolution processing on pre-stack seismic data to obtain pre-stack high-frequency seismic data, and / or to perform high-resolution processing on post-stack seismic data to obtain post-stack high-frequency seismic data. The processing range module is configured to determine the absorption coefficient processing range based on the target layer position and time window size. The amplitude spectrum calibration module is connected to both the processing range module and the data processing module, and is configured to average the logging amplitude spectra of all wells and fit them to a straight line, then sum and average the seismic amplitude spectra near each well and fit them to a straight line, calculating the amplitude ratio of the frequencies corresponding to the two straight lines as a calibration coefficient to calibrate the seismic spectrum. The absorption coefficient calculation module is connected to the amplitude spectrum calibration module and is configured to calculate the absorption coefficient using a dual-spectrum absorption coefficient calculation formula, wherein the formula is:

[0020]

[0021] Where α is the absorption coefficient, dimensionless; f is the frequency, in Hz; f s f is the starting frequency, in Hz; e The termination frequency is in Hz; A w (f) represents the amplitude of the logging amplitude spectrum, which is dimensionless; A s (f) represents the amplitude of the earthquake amplitude spectrum, which is dimensionless; N f The frequency number of the amplitude spectrum is dimensionless.

[0022] In another aspect, the present invention provides a computer device, the device comprising: a processor; and a memory storing a computer program, wherein when the computer program is executed by the processor, at least one of the absorption attenuation calculation method described above and the prediction method for fluid-bearing conditions in rock strata described above is implemented.

[0023] In another aspect, the present invention provides a computer-readable storage medium that, when executed by a computer program by a processor, implements at least one of the absorption attenuation calculation method described above and the method for predicting fluid-bearing conditions in rock strata as described above.

[0024] Compared with the prior art, the beneficial effects of the present invention may include at least one of the following:

[0025] (1) The present invention adopts a method of calculating the absorption coefficient by combining well logging spectrum constraints with seismic spectrum, which is significantly different from the traditional method that only uses seismic spectrum for calculation.

[0026] (2) This invention clarifies the absorption characteristics of the high-frequency band of the logging spectrum (the amplitude spectrum of the reflection coefficient of logging acoustic waves and density conversion) and the seismic spectrum. The relationship between the seismic spectrum and gas and water is not obvious in the low-frequency range, but obvious in the high-frequency band. The absorption characteristics of the high-frequency band of the seismic spectrum are also more obvious than those of the low-frequency band. This solves the problem that over-absorption compensation processing may affect the absorption attenuation characteristics and cause errors.

[0027] (3) The present invention uses high-resolution data to obtain the absorption coefficient, and obtains the absorption coefficient in the high frequency range, which is consistent with the theory that geophysical high frequencies are easy to attenuate, and is also more consistent with the actual situation.

[0028] (4) This invention proposes a method for calculating the absorption coefficient by combining two spectra, namely, subtracting the seismic spectrum energy from the well logging spectrum energy and then dividing by the well logging spectrum energy, which solves the problems of low resolution and low accuracy in the calculation of the existing absorption coefficient. Attached Figure Description

[0029] The above and other objects and / or features of the present invention will become clearer from the following description taken in conjunction with the accompanying drawings, in which:

[0030] Figure 1 A flowchart illustrating the absorption coefficient calculation process of an exemplary embodiment of the well logging spectrum constraint absorption attenuation calculation method of the present invention is shown.

[0031] Figure 2 An absorption coefficient planar diagram is shown as an exemplary embodiment of the absorption attenuation calculation method for well logging spectrum constraints of the present invention.

[0032] Figure 3 A schematic diagram of the calculation system structure of an exemplary embodiment of the well logging spectrum-constrained absorption attenuation calculation system of the present invention is shown.

[0033] Figure 4 A schematic diagram of a computer device structure is shown as an exemplary embodiment of the well logging spectrum-constrained absorption attenuation calculation system of the present invention.

[0034] Explanation of reference numerals in the attached figures:

[0035] 100-Absorption attenuation calculation system constrained by well logging spectrum, 101-Data processing module, 102-Processing range module, 103-Amplitude spectrum calibration module, 104-Absorption coefficient calculation module, 200-Computer equipment, 201-Memory, 202-Processor. Detailed Implementation

[0036] The following will describe in detail the absorption attenuation calculation method, system, and equipment under logging spectrum constraints of the present invention with reference to the accompanying drawings and specific embodiments.

[0037] Existing absorption coefficient calculations suffer from low resolution and low accuracy. The main reason for this is that absorption attenuation characteristics are more pronounced in the high-frequency band, while conventional seismic data have lower frequencies and narrower bandwidths. Furthermore, absorption compensation processing may affect absorption attenuation characteristics and introduce errors.

[0038] This invention, through extended research using high-resolution technology, has discovered new patterns and developed a method for calculating absorption attenuation under logging spectrum constraints.

[0039] To achieve the above objectives, the present invention provides a method for calculating absorption attenuation under logging spectrum constraints, the method comprising the following steps.

[0040] S1. Obtain high-resolution processed high-frequency seismic data.

[0041] Specifically, obtaining high-resolution processed high-frequency seismic data may include the following sub-steps:

[0042] S11. Input acoustic wave and density logging data, and convert the acoustic wave data into velocity data.

[0043] S12. Multiply the velocity by the density to obtain the wave impedance, and then calculate the reflection coefficient.

[0044] S13, Given a wavelet (Rake wavelet or other type of wavelet) and its dominant frequency.

[0045] S14. Calculate the composite record using the convolution algorithm.

[0046] S15. Establish the relationship between the synthetic record and the seismic record; the method for establishing the relationship is not restricted.

[0047] S16. Apply the relation to all seismic traces to obtain the inverted high-resolution profile or data volume.

[0048] Specifically, high-resolution processing is performed on pre-stack seismic data to obtain pre-stack high-frequency seismic data, and / or high-resolution processing is performed on post-stack seismic data to obtain post-stack high-frequency seismic data.

[0049] Specifically, the main frequency of high-frequency seismic data is above 50Hz, and the bandwidth is above 100Hz.

[0050] S2. Determine the processing range of the absorption coefficient based on the target layer position.

[0051] Specifically, the absorption coefficient processing range can be determined based on the target layer position and time window size.

[0052] S3. Based on the earthquake data, calculate the earthquake amplitude spectrum; based on the well logging data, calculate the well logging amplitude spectrum.

[0053] Specifically, well logging data may include sonic curves, or may include both sonic curves and density curves.

[0054] S4. Spatial interpolation is performed on the well logging amplitude spectrum to obtain a three-dimensional well logging spectrum data volume corresponding to the seismic amplitude spectrum.

[0055] Specifically, inverse distance weighted interpolation or kriging interpolation can be used to spatially interpolate the well logging amplitude spectrum. Interpolation creates a well logging amplitude spectrum data volume that corresponds one-to-one with the 3D seismic data and reflects actual geological patterns, facilitating subsequent calculations. Interpolation also establishes spatial geological feature constraints, simplifying subsequent data processing.

[0056] S5. Using the well logging amplitude spectrum as a standard, calibrate the seismic amplitude spectrum.

[0057] Specifically, the method for calibrating the seismic amplitude spectrum is as follows: the well logging amplitude spectra of all wells are averaged and fitted into a straight line; then, the seismic amplitude spectra near each well are summed, averaged, and fitted into a straight line again. The amplitude ratio of the frequencies corresponding to the two straight lines is used as a calibration coefficient to calibrate the seismic spectrum. Through calibration, the magnitude of the seismic amplitude spectrum is made consistent with the magnitude of the well logging amplitude spectrum as a whole, thereby calculating the relative change between the two.

[0058] S6. Calculate the absorption coefficient using the bispectral absorption coefficient calculation formula, which is as follows:

[0059]

[0060] Where α is the absorption coefficient, dimensionless; f is the frequency, in Hz; f s f is the starting frequency, in Hz; e The termination frequency is in Hz; A w (f) represents the amplitude of the logging amplitude spectrum, which is dimensionless; A s (f) represents the amplitude of the earthquake amplitude spectrum, which is dimensionless; N f The frequency number of the amplitude spectrum is dimensionless.

[0061] Specifically, an absorption coefficient plane diagram can be drawn based on the absorption coefficient calculation results.

[0062] Based on the above calculation flow and process, a flowchart of the absorption attenuation calculation method under well logging spectrum constraints is drawn as follows: Figure 1 As shown.

[0063] Another aspect of the present invention provides a method for predicting the fluid content of rock strata, which uses the absorption attenuation calculation method described in any one of the above to determine the absorption coefficient of the target layer, and based on the magnitude of the absorption coefficient, finds the gas-bearing distribution area and predicts the gas-water distribution.

[0064] Another aspect of the present invention provides an absorption attenuation calculation system under logging spectrum constraints.

[0065] In an exemplary embodiment of the absorption attenuation calculation system under logging spectrum constraints of the present invention, the absorption attenuation calculation system may include a data processing module, a processing range module, an amplitude spectrum calibration module, and an absorption coefficient calculation module.

[0066] The data processing module is configured to perform high-resolution processing on pre-stack seismic data to obtain pre-stack high-frequency seismic data, and / or to perform high-resolution processing on post-stack seismic data to obtain post-stack high-frequency seismic data.

[0067] The processing range module is configured to determine the processing range of the absorption coefficient based on the target layer position and the time window size.

[0068] The amplitude spectrum calibration module is connected to the processing range module and the data processing module respectively. It is configured to average the logging amplitude spectra of all wells and fit them into a straight line, then sum and average the seismic amplitude spectra near each well and fit them into a straight line, and calculate the amplitude ratio of the corresponding frequencies of the two straight lines as the calibration coefficient to calibrate the seismic spectrum.

[0069] The absorption coefficient calculation module is connected to the amplitude spectrum calibration module and is configured to calculate the absorption coefficient using a bispectral absorption coefficient calculation formula, which is:

[0070]

[0071] Where α is the absorption coefficient, dimensionless; f is the frequency, in Hz; f s f is the starting frequency, in Hz; e The termination frequency is in Hz; A w (f) represents the amplitude of the logging amplitude spectrum, which is dimensionless; A s (f) represents the amplitude of the earthquake amplitude spectrum, which is dimensionless; N f The frequency number of the amplitude spectrum is dimensionless.

[0072] At least one of the absorption attenuation calculation method under logging spectrum constraints and the prediction method of fluid-bearing conditions in rock formations according to the present invention can be programmed into a computer program and the corresponding program code or instructions can be stored in a computer-readable storage medium. When the program code or instructions are executed by a processor, the processor performs at least one of the above-mentioned absorption attenuation calculation method under logging spectrum constraints and the prediction method of fluid-bearing conditions in rock formations. The processor and memory can be included in a computer device.

[0073] An exemplary embodiment of another aspect of the present invention also provides a computer-readable storage medium storing a computer program. This computer-readable storage medium stores a computer program that, when executed by a processor, causes the processor to perform at least one of the absorption attenuation calculation method under logging spectrum constraints and the prediction method for fluid-bearing conditions in rock formations according to the present invention. This computer-readable recording medium is any data storage device capable of storing data readable by a computer system. Examples of computer-readable recording media include: read-only memory, random access memory, read-only optical disk, magnetic tape, floppy disk, optical data storage device, and carrier waves (such as data transmission via the Internet through wired or wireless transmission paths).

[0074] An exemplary embodiment of another aspect of the present invention also provides a computer device. The computer device includes a processor and a memory. The memory stores a computer program. The computer program is executed by the processor, causing the processor to execute a computer program for at least one of the absorption attenuation calculation method under logging spectrum constraints and the method for predicting fluid-bearing conditions in rock formations according to the present invention.

[0075] To better understand the present invention, the following description, in conjunction with the accompanying drawings and examples, further clarifies the content of the present invention, but the content of the present invention is not limited to the following embodiments.

[0076] Example 1

[0077] This example uses seismic data from a region in Changqing to predict the fluid conditions of a specific stratum in that region. This stratum is primarily a sandstone reservoir with widespread water content, and most wells are co-producing gas and water. The biggest challenge is gas and water identification, which requires locating gas-bearing areas while simultaneously predicting the gas and water distribution as accurately as possible.

[0078] Specifically, the following steps are included:

[0079] Step 1: Prepare the 3D post-stack seismic data volume for this region, with a dominant frequency of 35Hz and a frequency band of 8-70Hz.

[0080] Step 2: Conduct high-resolution post-stack seismic processing, with a main frequency of 75Hz and a frequency band of 8-150Hz.

[0081] In steps one and two, the post-stack seismic data is directly processed with high resolution. The dominant frequency refers to the frequency corresponding to the maximum amplitude in the average amplitude spectrum of the target layer, which is increased from 35Hz to 75Hz.

[0082] Step 3: Determine the target layer as the Paleozoic Shan 1-He 8 sandstone reservoir section, with a time window thickness of approximately 70ms.

[0083] The top boundary of the target layer is Box 8 Top, and the bottom boundary is Mountain 1 Bottom.

[0084] Step 4: Read all seismic data. Calculate the amplitude spectrum of high-resolution seismic data within the target layer time window to form a three-dimensional amplitude spectrum data volume.

[0085] Step 5: Extract the acoustic and density curves of the target formation from nearly 59 wells in the area and convert them into reflection coefficient curves.

[0086] Among these steps, the well logging curves need to be converted to the time domain of the seismic profile, and the sampling rate should be the same as that of the seismic data, which is 1ms.

[0087] Step 6: Convert the well logging reflection coefficient curve into an amplitude spectrum.

[0088] Among them, the distribution range of the well logging spectrum is very high, reaching 500Hz at a sampling rate of 1ms, but only values ​​within the effective high cutoff frequency of the seismic profile can be extracted in the calculation.

[0089] Step 7: Spatial interpolation of the well logging spectrum is performed using the Kriging interpolation method to obtain a three-dimensional well logging spectrum data volume corresponding to the seismic spectrum.

[0090] The data volume can be obtained by ordinary kriging interpolation of the logging spectrum, or other interpolation methods can be used.

[0091] Step 8: Average the logging spectra of all 59 wells and fit them into a straight line. Then, sum and average the seismic spectra near each well and fit them into a straight line. Calculate the amplitude ratio of the frequencies corresponding to the two straight lines as calibration coefficients to calibrate the seismic spectra.

[0092] Among them, the logging spectra of 59 wells were basically linear, with weak low-frequency energy and strong high-frequency energy. The seismic spectrum generally showed an undulating oscillation pattern, reflecting the selective absorption of seismic reflections by the reservoir and fluids, or changes in absorption intensity, and was generally linear.

[0093] Step 9: Calculate the absorption coefficient using the following formula and generate a planar graph.

[0094]

[0095] The final result is an absorption coefficient plane diagram as shown below. Figure 2 As shown, the absorption coefficient planar plot is created after obtaining the absorption coefficient profile or 3D data volume. It extracts absorption coefficient parameters within the target layer, including average, maximum, and minimum values, to display the planar distribution of the absorption coefficient. It should be noted that... Figure 2The color scale in the graph represents the absorption coefficient values, ranging from 0 to 0.4 (it should be noted that this range is only for illustrating the color scale range and does not represent the actual range of the extracted absorption coefficient; the complete range is 0-1). Low-value areas (white) indicate predicted water-bearing or dry well areas; high-value areas (gray-black) indicate areas favorable for gas production. The graph also includes a bubble chart of the tested gas production; bubble size indicates relative production levels. Larger bubbles are generally located in or near high-value areas, with an overall accuracy rate of approximately 80%.

[0096] Example 2

[0097] like Figure 3 As shown, the well logging spectrum-constrained absorption attenuation calculation system 100 includes a data processing module 101, a processing range module 102, an amplitude spectrum calibration module 103, and an absorption coefficient calculation module 104.

[0098] The data processing module 101 is used to perform high-resolution processing on pre-stack seismic data to obtain pre-stack high-frequency seismic data, and / or to perform high-resolution processing on post-stack seismic data to obtain post-stack high-frequency seismic data.

[0099] The processing range module 102 is used to determine the processing range of the absorption coefficient based on the target layer position and the time window size;

[0100] The amplitude spectrum calibration module 103 is connected to the processing range module 102 and the data processing module 101 respectively. It is used to average the logging amplitude spectrum of all wells and fit it into a straight line, then sum and average the seismic amplitude spectrum of each well and fit it into a straight line, and calculate the amplitude ratio of the corresponding frequencies of the two straight lines as the calibration coefficient to calibrate the seismic spectrum.

[0101] The absorption coefficient calculation module 104 is connected to the amplitude spectrum calibration module 103 and is used to calculate the absorption coefficient using the bispectral absorption coefficient calculation formula, which is:

[0102]

[0103] Where α is the absorption coefficient, dimensionless; f is the frequency, in Hz; f s f is the starting frequency, in Hz; e The termination frequency is in Hz; A w (f) represents the amplitude of the logging amplitude spectrum, which is dimensionless; A s (f) represents the amplitude of the earthquake amplitude spectrum, which is dimensionless; N f The frequency number of the amplitude spectrum is dimensionless.

[0104] Example 3

[0105] like Figure 4As shown, a computer device 200 includes a memory 201 and a processor 202. The memory 201 stores computer programs. The computer programs are executed by the processor, causing the processor to execute at least one of the computer programs for calculating absorption attenuation under logging spectrum constraints and predicting fluid-bearing conditions in rock formations according to the present invention.

[0106] Although the present invention has been described above in conjunction with exemplary embodiments and accompanying drawings, those skilled in the art should understand that various modifications can be made to the above embodiments without departing from the spirit and scope of the claims.

Claims

1. A method for calculating absorption attenuation under logging spectrum constraints, characterized in that, The absorption attenuation calculation method includes the following steps: Obtain high-resolution processed high-frequency seismic data; Determine the processing range of the absorption coefficient based on the target layer level; Based on the earthquake data, the earthquake amplitude spectrum is calculated; based on the well logging data, the well logging amplitude spectrum is calculated. Spatial interpolation of the well logging amplitude spectrum yields a three-dimensional well logging spectrum data volume corresponding to the seismic amplitude spectrum; The seismic amplitude spectrum was calibrated using the well logging amplitude spectrum as a standard. The absorption coefficient is calculated using the bispectral absorption coefficient calculation formula, which is as follows: ， in, α The absorption coefficient is dimensionless. f Frequency, Hz; f s The starting frequency is in Hz. f e The termination frequency is in Hz. A w (f) The amplitude of the logging amplitude spectrum is dimensionless. A s (f) The amplitude of the earthquake amplitude spectrum is dimensionless. N f The frequency number of the amplitude spectrum is dimensionless. The method for calibrating the seismic amplitude spectrum is as follows: average the logging amplitude spectra of all wells and fit them into a straight line, then sum and average the seismic amplitude spectra near each well and fit them into a straight line, and calculate the amplitude ratio of the corresponding frequencies of the two straight lines as the calibration coefficient to calibrate the seismic spectrum.

2. The method for calculating absorption attenuation under logging spectrum constraints according to claim 1, characterized in that, The absorption attenuation calculation method includes: performing high-resolution processing on pre-stack seismic data to obtain pre-stack high-frequency seismic data, and / or performing high-resolution processing on post-stack seismic data to obtain post-stack high-frequency seismic data.

3. The method for calculating absorption attenuation under logging spectrum constraints according to claim 1, characterized in that, The absorption attenuation calculation method further includes: determining the absorption coefficient processing range based on the target layer position and time window size.

4. The method for calculating absorption attenuation under logging spectrum constraints according to claim 1, characterized in that, Spatial interpolation of well logging amplitude spectra is performed using inverse distance weighted interpolation or kriging interpolation.

5. The method for calculating absorption attenuation under logging spectrum constraints according to claim 1, characterized in that, The absorption attenuation calculation method further includes: drawing an absorption coefficient plane diagram based on the absorption coefficient calculation results.

6. The method for calculating absorption attenuation under logging spectrum constraints according to claim 1, characterized in that, The logging data includes acoustic curves, or includes both acoustic curves and density curves.

7. The method for calculating absorption attenuation under logging spectrum constraints according to claim 1, characterized in that, The high-frequency seismic data has a main frequency of 50Hz or higher and a bandwidth of 100Hz or higher.

8. A method for predicting the fluid content of rock strata, characterized in that, The absorption coefficient of the target layer is determined by the absorption attenuation calculation method as described in any one of claims 1 to 7, and the gas-bearing distribution area is found and the gas-water distribution is predicted based on the magnitude of the absorption coefficient.

9. A system for calculating absorption attenuation under logging spectrum constraints, characterized in that, The absorption attenuation calculation system includes a data processing module, a processing range module, an amplitude spectrum calibration module, and an absorption coefficient calculation module, wherein... The data processing module is configured to perform high-resolution processing on pre-stack seismic data to obtain pre-stack high-frequency seismic data, and / or to perform high-resolution processing on post-stack seismic data to obtain post-stack high-frequency seismic data. The processing range module is configured to determine the absorption coefficient processing range based on the target layer position and the time window size; The amplitude spectrum calibration module is connected to the processing range module and the data processing module respectively. It is configured to average the logging amplitude spectrum of all wells and fit it into a straight line, then sum and average the seismic amplitude spectrum near each well and fit it into a straight line, and calculate the amplitude ratio of the corresponding frequencies of the two straight lines as the calibration coefficient to calibrate the seismic spectrum. The absorption coefficient calculation module is connected to the amplitude spectrum calibration module and is configured to calculate the absorption coefficient using a bispectral absorption coefficient calculation formula, which is: ， in, α The absorption coefficient is dimensionless. f Frequency, Hz; f s The starting frequency is in Hz. f e The termination frequency is in Hz. A w (f) The amplitude of the logging amplitude spectrum is dimensionless. A s (f) The amplitude of the earthquake amplitude spectrum is dimensionless. N f The frequency number of the amplitude spectrum is dimensionless.

10. A computer device, characterized in that, The device includes: processor; A memory storing a computer program that, when executed by a processor, implements at least one of the absorption attenuation calculation method as described in any one of claims 1 to 7 and the prediction method as described in claim 8.

11. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by a processor, it implements at least one of the absorption attenuation calculation method as described in any one of claims 1 to 7 and the prediction method as described in claim 8.

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