Method and system for judging direction of main object source by utilizing edge of earthquake preaccrete

Abstract

The invention relates to the technical field of petroleum and natural gas exploration, in particular to a method and system for judging the direction of a main object source by using an earthquake front accumulation body edge. According to the method, the process and the implementation system are established, the direction of the main source of the preproduct is rapidly judged, the azimuth angle of the preproduct can be quantitatively calculated, and the periods of different preproducts are judged. According to the method, the edge detection technology in the field of digital images is applied to seismic preproduct identification and main source discrimination of a sedimentary system, traditional seismic section preproduct angle calculation is replaced by frequency division amplitude RGB fusion stratigraphic slice morphological characteristics, preproduct macroscopic distribution and periods are more intuitive, and quantitative main source direction calculation can be realized at the same time.

Description

Technical Field

[0001] The present disclosure relates to the technical field of oil and gas exploration, and in particular to a method and system for determining the direction of a main provenance by utilizing the edge of a seismic foreset body. Background Art

[0002] With the advancement of seismic exploration technology, provenance analysis based on seismic data is becoming increasingly widespread. This is especially true in the absence of outcrops and core samples, making it impossible to effectively test and analyze relevant sediment sources. Seismic data can be used to identify sediment provenance. Seismic reflection structures, especially progradational structures, indicate the direction of paleocurrents and, to a certain extent, the direction of provenance. This is the primary basis for identifying provenance based on seismic progradational reflection structures. Progradational reflection structures demonstrate progradation in the central area of ​​the basin along the same axial line, representing the advance of sediments into the basin and providing a crucial basis for provenance analysis.

[0003] Currently, the identification of provenance direction based on seismic foreset reflection structures mostly relies on qualitative identification by observing a large number of seismic profiles, or manually reading the foreset angle through seismic profiles and making "rose" maps to determine the main provenance direction. Such methods are often highly subjective, cumbersome and lack quantitative judgment. At the same time, it is difficult to effectively identify the stage of the foreset bodies in areas where multiple foreset bodies overlap. Summary of the Invention

[0004] In response to the above problems, the present disclosure provides a method and system for determining the direction of the main material source using the edge of the seismic foreset body, which is used to establish a process and implement a system to quickly determine the direction of the main material source of the foreset body, and at the same time can quantitatively calculate the azimuth of the foreset body and distinguish the periods of different foreset bodies.

[0005] In a first aspect, the present disclosure provides a method for determining the direction of a main provenance using the edge of an earthquake foreset body, the method comprising:

[0006] The drilling sequence division and comparison are carried out in the research area of ​​the seismic foreset body, well-seismic calibration and seismic sequence interpretation are carried out, and the isochronous stratigraphic framework of the seismic foreset body is established to obtain a three-dimensional seismic data body constrained by the isochronous stratigraphic framework;

[0007] The 3D seismic data volume with isochronous stratigraphic grid constraints is processed by frequency division and RGB fusion to obtain the frequency division fusion data volume;

[0008] Perform stratigraphic slicing processing on the frequency-division fusion data volume to generate stratigraphic slice images of the seismic foreset volume;

[0009] Performing edge detection processing on the stratum slice image to obtain an edge detection image of the stratum slice;

[0010] The contours in the edge detection image of the stratigraphic slice are connected into a curve, and the curvature of the curve is calculated. The direction indicated by the line of maximum curvature of each curve is the main source direction of the earthquake foreset body.

[0011] Furthermore, the drilling sequence division and comparison are carried out for the seismic foreset body in the research area, well-seismic calibration and seismic sequence interpretation are carried out, and an isochronous stratigraphic framework of the seismic foreset body is established to obtain a 3D seismic data volume constrained by the isochronous stratigraphic framework, including:

[0012] Carry out drilling sequence division and comparison in the seismic foreset study area, and divide the target strata into third-order, fourth-order and fifth-order sequences by integrating cores, thin sections, well logging curves and well logging lithofacies combinations, and establish a drilling isochronous sequence stratigraphic division scheme;

[0013] Based on the isochronous sequence stratigraphic division scheme, the sequences were calibrated to the seismic data through well-seismic synthetic record calibration. Combined with the seismic reflection termination model, seismic sequence interpretation was carried out using 3D seismic data, and an isochronous sequence stratigraphic framework was constructed in the study area to obtain a 3D seismic data volume constrained by the isochronous stratigraphic framework.

[0014] Furthermore, the 3D seismic data volume with isochronous stratigraphic grid constraints is subjected to frequency division and RGB fusion processing to obtain a frequency division fusion data volume, including:

[0015] The three-dimensional seismic data volume is subjected to phase shift, frequency division and RGB fusion in sequence to obtain the frequency division fusion data volume.

[0016] Furthermore, the three-dimensional seismic data volume is subjected to phase shifting, frequency division and RGB fusion in sequence to obtain a frequency division fusion data volume, including:

[0017] The 3D seismic data volume of the target area is processed by seismic phase shift using Geoscope software;

[0018] Frequency parameters are selected and frequency division processing is performed on the aforementioned phase-shifted seismic data volume using Geoscope software, dividing the seismic data volume into high frequency, medium frequency, and low frequency. The frequency parameters are determined by calibration of well-seismic synthetic records.

[0019] The three frequency division data volumes of high frequency, medium frequency and low frequency obtained by frequency division are fused by RGB frequency division through Geoscope software to obtain the frequency division fusion data volume, where R represents the low frequency data volume, G represents the medium frequency data volume, and B represents the high frequency data volume.

[0020] Furthermore, the frequency parameters are determined by calibration of well-seismic synthetic records, including:

[0021] The frequency of the frequency-divided data body corresponding to the third-level sequence in the three-dimensional seismic data body is low frequency, the frequency of the frequency-divided data body corresponding to the fourth-level sequence is medium frequency, and the frequency of the frequency-divided data body corresponding to the fifth-level sequence is high frequency.

[0022] Furthermore, stratigraphic slicing processing is performed on the frequency-division fusion data volume to generate stratigraphic slice images of the seismic foreset volume, including:

[0023] The stratigraphic slice image of the target area of ​​the seismic foreset is obtained by performing stratigraphic slice processing on the frequency-divided fusion data volume using Geoscope software.

[0024] The stratigraphic slices were made using the equal-proportional stratigraphic slice method, with the top and bottom seismic sequences of the third-order sequence as the boundaries and a fixed sampling interval to produce equal-proportional stratigraphic slices.

[0025] Furthermore, edge detection processing is performed on the stratum slice image to obtain detection results, including:

[0026] Edge detection is performed using the Canny algorithm, which performs filtering, enhancement, suppression, and screening in sequence.

[0027] Furthermore, edge detection is performed using the Canny algorithm, which performs filtering, enhancement, suppression, and screening processing in sequence, including:

[0028] Gaussian filtering is used to filter the image;

[0029] After the image is filtered, the Sobel operator is used to calculate the horizontal and vertical gradients respectively. The total gradient direction is calculated from the calculated horizontal and vertical gradients to obtain the gradient image.

[0030] Perform non-maximum suppression on the gradient image, use non-maximum suppression to find the local maximum of the pixel point, set the grayscale value corresponding to the non-maximum value to 0, and obtain the suppressed image;

[0031] A low threshold and a high threshold are selected for the suppressed image respectively. Points smaller than the low threshold are treated as false edges and set to 0, while points larger than the high threshold are treated as strong edges and set to 1 to obtain a high threshold image. The edges in the high threshold image are linked into contours. When the endpoint of the contour is reached, a point that meets the low threshold is searched among the 8 neighborhood points of the breakpoint. New edges are then collected based on this point until the entire image is closed to obtain an edge detection image of the stratum slice.

[0032] Furthermore, the method further includes: if there are multiple earthquake foreset bodies, based on the edge detection image of the stratigraphic slice, analyzing the contour lines in the edge detection result to obtain the development stages of the multiple foreset bodies.

[0033] Furthermore, it also includes: judging the distribution characteristics of the lithology and thickness of the foreset body through image color analysis based on the seismic foreset body stratum slice image, combined with the main material source direction of the foreset body obtained by curvature calculation.

[0034] In a second aspect, the present disclosure provides a system for determining the direction of a main source using the edge of an earthquake foreset body, comprising a data body construction unit, a frequency division unit, a slicing unit, an edge detection unit, and an analysis unit connected in sequence;

[0035] The data volume construction unit is used to carry out drilling sequence division and comparison in the seismic foreset body study area, perform well-seismic calibration and seismic sequence interpretation, establish an isochronous stratigraphic framework for the seismic foreset body, and obtain a 3D seismic data volume constrained by the isochronous stratigraphic framework;

[0036] The frequency division unit is used to perform frequency division and RGB fusion processing on the three-dimensional seismic data volume to obtain a frequency division fusion data volume;

[0037] Slicing unit, used to perform stratigraphic slicing processing on the frequency-division fusion data volume to generate stratigraphic slice images of the seismic foreset volume;

[0038] An edge detection unit is used to perform edge detection processing on the stratum slice image to obtain an edge detection image of the stratum slice;

[0039] The analysis unit is used to connect the contours in the edge detection image of the stratum slice into a curve and calculate the curvature of the curve. The direction indicated by the line of maximum curvature of each curve is the main source direction of the earthquake foreset body.

[0040] In a third aspect, the present disclosure provides an electronic device, comprising 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;

[0041] a memory storing a computer program;

[0042] The processor is configured to implement the above-mentioned method of determining the direction of the main source by using the edge of the earthquake foreset body when executing the computer program stored in the memory.

[0043] In a fourth aspect, the present disclosure provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the above-mentioned method of determining the direction of a main provenance by using the edge of a seismic foreset body.

[0044] The present disclosure has at least the following beneficial effects:

[0045] This paper applies edge detection technology in the field of digital images to the identification of seismic foreset bodies and the discrimination of the main provenance of sedimentary systems. By fusing the morphological characteristics of stratigraphic slices with frequency-division amplitude RGB, the traditional calculation of the foreset angle of seismic sections is replaced by that of conventional seismic sections. The macroscopic distribution and period of the foreset bodies are more intuitive, and quantitative calculation of the main provenance direction can be achieved.

[0046] Other features and advantages of the present disclosure will be described in the following description, and in part will become apparent from the description, or will be understood by practicing the present disclosure. The purpose and other advantages of the present disclosure can be achieved and obtained through the structures indicated in the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] In order to more clearly illustrate the embodiments of the present disclosure or the technical solutions in the prior art, a brief introduction will be given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0048] Figure 1 This is a flow chart of a method for determining the direction of a main source according to an embodiment of the present disclosure;

[0049] Figure 2 This is a schematic diagram of a system for determining the direction of a primary source of matter according to an embodiment of the present disclosure;

[0050] Figure 3 It is a schematic diagram of the structure of an electronic device;

[0051] Figure 4 Schematic diagram of well-seismic calibration and sequence interpretation section of third-level sequence (left: 0-degree phase; right: 90-degree phase);

[0052] Figure 5 This is a schematic diagram of the calibration comparison of the 22HZ and 45HZ seismic sections of the earthquake prograde;

[0053] Figure 6 It is a schematic diagram of stratigraphic slice;

[0054] Figure 7 This is a schematic diagram of the stratigraphic slice after frequency division and RGB fusion;

[0055] Figure 8 This is a schematic diagram of the edge detection of the earthquake foreset;

[0056] Figure 9 This is a schematic diagram of the main source direction for interpretation of seismic foreset edge detection results and curvature calculation;

[0057] Figure 10 Schematic diagram of the superposition of earthquake foreset edge detection results and RGB frequency-division amplitude fusion slices. DETAILED DESCRIPTION

[0058] To make the objectives, technical solutions, and advantages of the embodiments of the present disclosure more clear, the technical solutions in the embodiments of the present disclosure will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present disclosure, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present disclosure without making any creative efforts shall fall within the scope of protection of the present disclosure.

[0059] Currently, the identification of provenance direction based on seismic foreset reflection structures mostly relies on qualitative identification by observing a large number of seismic profiles, or manually reading the foreset angle through seismic profiles and making "rose" maps to determine the main provenance direction. Such methods are often highly subjective, cumbersome and lack quantitative judgment. At the same time, it is difficult to effectively identify the stage of the foreset bodies in areas where multiple foreset bodies overlap.

[0060] To this end, the present invention proposes a method and system for intelligently determining the direction of the main material source through seismic foreset edge detection, and establishes a process and implementation system to quickly determine the direction of the main material source of the foreset, while quantitatively calculating the azimuth of the foreset and distinguishing the periods of different foreset bodies.

[0061] like Figure 1 As shown, the present disclosure provides a method for determining the direction of the main provenance by using the edge of the earthquake foreset body, the method comprising:

[0062] S101: Conduct drilling sequence division and comparison in the seismic foreset study area, perform well-seismic calibration and seismic sequence interpretation, establish an isochronous stratigraphic framework for the seismic foreset, and obtain a 3D seismic data volume constrained by the isochronous stratigraphic framework;

[0063] S102, performing frequency division and RGB fusion processing on the 3D seismic data volume to obtain a frequency division and fusion data volume;

[0064] S103, performing stratigraphic slicing processing on the frequency division fusion data volume to generate a stratigraphic slicing image of the seismic foreset volume;

[0065] S104, performing edge detection processing on the stratum slice image to obtain an edge detected image of the stratum slice;

[0066] S105 , connecting the contours in the edge detection image of the stratum slice into a curve, and calculating the curvature of the curve. The direction indicated by the maximum curvature line of each curve is the main provenance direction of the earthquake foreset body.

[0067] When implementing it, the following steps are taken:

[0068] Step S101: Establish an isochronous stratigraphic framework for the seismic foreset. Drilling sequence division and comparison are performed on the seismic foreset study area. Cores, thin sections, well logs, and well logging lithofacies are used to classify the target strata into tertiary, quaternary, and quinary sequences, and a drilling isochronous sequence stratigraphic division scheme is established. Third-order sequences are calibrated to seismic data using well-seismic synthetic log calibration. Seismic sequence interpretation is performed using 3D seismic data, combining seismic reflection termination patterns, including onlap, underlap, and erosion, to establish an isochronous sequence stratigraphic framework for the study area.

[0069] Step S102: Frequency division and RGB fusion processing of seismic data volume. This step mainly includes three aspects: phase shift, frequency division, and RGB fusion. First, based on step S101, the three-dimensional seismic data volume of the target area is subjected to seismic phase shift processing through Geoscope software, and the appropriate phase is selected to perform phase shift on the three-dimensional seismic data volume. Different strata often have different seismic response amplitudes, frequencies, etc. due to different lithologies. Through seismic phase shifting, a better correspondence between the peaks or troughs and the strata is achieved. Secondly, the appropriate frequency parameters are selected to perform frequency division processing on the seismic data volume after the above-mentioned phase shift through Geoscope software. Because different seismic frequencies have different tuning thicknesses for geological bodies, seismic data of different frequencies reflect geological bodies of different thicknesses. For example, high-frequency seismic data volumes often correspond to the responses of thin geological bodies, while low-frequency seismic data volumes often correspond to the responses of thick geological bodies. The seismic data volume is divided into high frequency, medium frequency, and low frequency. The frequency parameters are determined by calibrating the artificial synthetic drilling records in step S101. The frequency corresponding to the frequency-divided data volume with a good correspondence to the seismic sequence interface corresponding to the third-level sequence in step S101 is low-frequency, the frequency corresponding to the frequency-divided data volume with a good correspondence to the seismic sequence interface corresponding to the fourth-level sequence in step S101 is medium-frequency, and the frequency corresponding to the frequency-divided data volume with a good correspondence to the seismic sequence interface corresponding to the fifth-level sequence in step S101 is high-frequency. Thus, three seismic data volumes with low frequency, medium frequency, and high frequency are obtained. Finally, RGB fusion is performed. The three frequency-divided data volumes obtained by frequency division are fused by RGB frequency division using Geoscope software to obtain a frequency-divided fused data volume, where R represents the low-frequency data volume, G represents the medium-frequency data volume, and B represents the high-frequency data volume. Compared with conventional seismic data volumes, the RGB-fused data volume can reflect the response of thick, medium, and thin geological bodies through the three RGB colors. On the other hand, the brightness and darkness of the image can reflect the amplitude value of the seismic data volume, which has a better response to geological bodies of different lithologies.

[0070] Step S103: Generate stratigraphic slice images of the seismic foreset. Geoscope software is used to perform stratigraphic slicing on the frequency-divided fusion data volume obtained in step S102, generating stratigraphic slice images of the target area of ​​the seismic foreset. Stratigraphic slicing is performed using the equal-proportional stratigraphic slicing method, with the top and bottom seismic sequences of the third-order stratigraphic sequence as the boundaries and a fixed sampling interval.

[0071] Step S104: Edge detection of the stratigraphic slice image. Edge detection is performed using the Canny algorithm, which includes four aspects: filtering, enhancement, suppression, and screening. For the stratigraphic slices obtained in step S103, the slice image with the most significant seismic foreset features is selected for edge detection. Edge detection is performed using a MATLAB program. The first step is filtering, the main purpose of which is to eliminate noise. Using the Gaussian filter method, a weighted average is performed based on the grayscale values ​​of the pixel to be filtered and its neighboring points according to the parameter rule generated by the Gaussian formula, thereby effectively filtering out high-frequency noise. The second step is enhancement, the main purpose of which is to calculate the gradient and gradient direction of the stratigraphic slice image. The Sobel operator is used to calculate the horizontal and vertical gradients respectively, and the total gradient direction is further calculated from the calculated horizontal and vertical gradients. Next, suppression is performed, which involves performing non-maximum suppression on the gradient image. Non-maximum suppression is used to find the local maximum value of the pixel point, and the grayscale value corresponding to the non-maximum value is set to 0. This can eliminate a large number of non-edge pixels. Finally, filtering is performed. Two thresholds are selected. Points below the lower threshold are considered false edges and set to 0. Points above the higher threshold are considered strong edges and set to 1. Pixels in between require further inspection. Edges in the high-threshold image are linked to form contours. When a contour endpoint is reached, the algorithm searches for a point in the breakpoint's eight neighborhoods that meets the lower threshold. New edges are then collected based on these points until the entire image is closed. Step S104 yields an edge-detected image of the stratum slice.

[0072] Step S105: Calculation and analysis of the main provenance direction of the seismic foreset body. The contours from the edge detection results of the seismic foreset body stratigraphic slice image obtained in step S104 are connected into a curve, and the curvature of the curve is further calculated. The direction indicated by the line of maximum curvature of each curve is the main provenance direction of the seismic foreset body. Furthermore, if multiple seismic foreset bodies exist, the development stages of these foreset bodies can be analyzed based on the edge detection results and the connecting contours from the edge detection results. Generally, later-developed foreset bodies intersect earlier-developed foreset bodies. Furthermore, the lithology and thickness distribution characteristics of the seismic foreset body stratigraphic slices produced in step S103 can be determined by image color analysis combined with the main provenance direction of the foreset body obtained through curvature calculation. Generally, along the main provenance direction, the foreset body stratigraphic slices show a change from light to dark and from red to blue, reflecting the transition from coarse-grained sediments to fine-grained sediments and from thick geological bodies to thin geological bodies.

[0073] like Figure 2 As shown, the present disclosure provides a system for determining the direction of the main source by using the edge of the earthquake foreset body, comprising a data body construction unit 201, a frequency division unit 202, a slicing unit 203, an edge detection unit 204 and an analysis unit 205 connected in sequence;

[0074] The data volume construction unit 201 is used to carry out drilling sequence division and comparison in the seismic foreset body research area, perform well-seismic calibration and seismic sequence interpretation, establish an isochronous stratigraphic framework for the seismic foreset body, and obtain a three-dimensional seismic data volume;

[0075] The frequency division unit 202 is used for frequency division and RGB fusion processing of the 3D seismic data volume to obtain a frequency division and fusion data volume;

[0076] Slicing unit 203, used for performing stratigraphic slicing processing on the frequency division fusion data volume to generate stratigraphic slice images of the seismic foreset volume;

[0077] The edge detection unit 204 is used to perform edge detection processing on the stratum slice image to obtain an edge detection image of the stratum slice;

[0078] The analysis unit 205 is used to connect the contours in the edge detection image of the stratum slice into a curve and calculate the curvature of the curve. The direction indicated by the maximum curvature line of each curve is the main provenance direction of the seismic foreset body.

[0079] like Figure 3 As shown, the present disclosure provides an electronic device, including a processor 301, a communication interface 302, a memory 303 and a communication bus 304, wherein the processor 301, the communication interface 302 and the memory 303 communicate with each other through the communication bus 304;

[0080] Memory 303, storing computer programs;

[0081] The processor 301 is configured to implement the above-mentioned method of determining the direction of the main provenance by using the edge of the earthquake foreset body when executing the computer program stored in the memory 303 .

[0082] The present disclosure provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the above-mentioned method for determining the direction of a main provenance by using the edge of a seismic foreset body.

[0083] The computer-readable storage medium may be included in the device / apparatus described in the above embodiments, or may exist independently without being incorporated into the device / apparatus. The computer-readable storage medium carries one or more programs, which, when executed, implement the method according to the embodiments of the present disclosure.

[0084] According to an embodiment of the present disclosure, a computer-readable storage medium may be a non-volatile computer-readable storage medium, such as, but not limited to, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination thereof. In the present disclosure, a computer-readable storage medium may be any tangible medium containing or storing a program that can be used by or in conjunction with an instruction execution system, apparatus, or device.

[0085] In order to enable those skilled in the art to better understand the present disclosure, the principles of the present disclosure are described as follows with reference to the accompanying drawings:

[0086] In the three-dimensional seismic data of a certain study area, earthquake foreset bodies are widely developed in the Lower Cambrian, and drilling reveals the seismic response of mound-shoal bodies. The main material source is intelligently determined through the edge detection of the earthquake foreset body in the study area to further illustrate the technical solution of the present disclosure.

[0087] This embodiment provides a method and system for intelligently determining the direction of the main source through earthquake foreset edge detection, which includes the following steps: Figure 1 As shown:

[0088] Step S101: establishing an isochronous stratigraphic framework for the earthquake foreset;

[0089] Step S102: frequency division and RGB fusion processing of seismic data volume;

[0090] Step S103: generating a stratigraphic slice image of the seismic foreset;

[0091] Step S104: edge detection processing of stratum slice image;

[0092] Step S105: Calculation of the main source direction of the earthquake foreset body and result analysis;

[0093] In step S101, drilling sequence division and comparison are performed in the study area. Cores, thin sections, well logs, and well logging lithofacies are integrated to divide the target strata into stratigraphic sequences, and a drilling isochronous sequence stratigraphic division scheme is established. Through well-seismic synthetic log calibration, the third-level sequences are calibrated to the seismic data. Seismic sequence interpretation is performed using 3D seismic data to construct an isochronous sequence stratigraphic framework for the study area.

[0094] In step S102, all processing is done by Geoscope software. First, by selecting different phases to carry out the shift test, the results show that the sequence and seismic correspondence is better after the 90-degree phase shift. For example, SQ4 corresponds to half a peak and half a trough in the original 0-phase section, but corresponds to a complete trough after the 90-degree phase shift. Therefore, the 90-degree phase shift is adopted to carry out the 90-degree phase shift processing on the seismic data ( Figure 4 ). Secondly, if Figure 5 As shown, frequency separation processing was performed on the seismic data. Through continuous testing, the study area was divided into three frequency seismic data: 22 Hz, 45 Hz, and 60 Hz, corresponding to low-frequency, medium-frequency, and high-frequency data volumes, respectively. Frequency parameters were calibrated through well-to-seismic calibration in step S101. Seismic data with a dominant frequency of 22 Hz correlated well with single-well third-order sequences, such as the internal foreset phase of SQ4, which correlated well with single-well third-order sequences. Seismic data with a dominant frequency of 45 Hz also correlated better with single-well fourth-order sequences. Based on this, RGB fusion was further performed. During the fusion, the 22 Hz low-frequency seismic data was assigned an R value, the 45 Hz medium-frequency data was assigned a G value, and the 60 Hz high-frequency data was assigned a B value. The RGB fusion process yielded the fused seismic data volume.

[0095] In step S103, the RGB fusion data volume obtained in step S102 is used to generate stratigraphic slice images in an equal-proportional manner. All processing is completed by Geoscope software. When producing stratigraphic slices, 10 equal-proportional stratigraphic slices are generated with the top and bottom interfaces of the seismic foreset development layer as the boundary ( Figure 6 ), combined with the geological background analysis of the study area, it is believed that the 9th stratigraphic slice image is most consistent with the geological law of the seismic foreset body development. Therefore, the 9th stratigraphic slice image is selected as the image for subsequent calculation of the main provenance direction ( Figure 7 ).

[0096] In step S104, edge detection is performed on the stratigraphic slice image obtained in step S103. All processing is done by Matlab software. The stratigraphic slice image obtained in step S103 is subjected to Gaussian filtering to remove noise, and then the horizontal and vertical gradients are calculated respectively by the Sobel operator. The total gradient image is further calculated from the calculated horizontal and vertical gradients, and then the gradient image is subjected to non-maximum suppression and threshold screening to obtain the final edge detection image. After edge detection processing, the output image better reflects the layer structure of the earthquake foreset body ( Figure 8 ).

[0097] In step S105, the edge detection map obtained in step S104 is combined with the geological background of the target layer to draw the layer structure curve of the earthquake foreset body. The curvature of each curve is further calculated, and the maximum curvature of each curve is connected into a line. The indicated direction is the main provenance direction of the earthquake foreset body. For example, the main provenance direction of the target layer SQ4 after the maximum curvature is calculated is 45 degrees ( Figure 9 ). At the same time, the curve obtained after edge detection is superimposed with the stratigraphic slice image obtained in step S103, and the development period and thickness lithologic variation law of multiple foreset bodies can be analyzed. For example, the target stratum SQ4 identifies two phases of foreset bodies, the first phase (yellow dotted circle layer) and the second phase (green dotted circle layer). Among them, the main provenance direction of the foreset body of the first phase (yellow dotted circle layer) is 90 degrees, and the main provenance direction of the foreset body of the second phase (green dotted circle layer) is 45 degrees. Through the cutting relationship analysis, the second phase cuts the first phase, indicating that the development of the second phase is later than that of the first phase. At the same time, according to the RGB frequency division amplitude fusion slice color, the foreset bodies of the two phases change from bright to dark, and from red to blue along the main provenance direction, reflecting the geological law of the evolution from strong amplitude granular sediments to weak amplitude mud-rich fine-grained sediments, and the evolution from thick layers to thin layers ( Figure 10 ).

[0098] Although the present disclosure has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present disclosure.

Claims

1. A method for determining the direction of the main source using the edge of an earthquake foreset, characterized in that: The method comprises: The drilling sequence division and comparison are carried out in the research area of ​​the seismic foreset body, well-seismic calibration and seismic sequence interpretation are carried out, and an isochronous stratigraphic framework of the seismic foreset body is established to obtain a three-dimensional seismic data volume constrained by the isochronous stratigraphic framework; The 3D seismic data volume with isochronous stratigraphic grid constraints is processed by frequency division and RGB fusion to obtain the frequency division fusion data volume; Perform stratigraphic slicing processing on the frequency-division fusion data volume to generate stratigraphic slice images of the seismic foreset volume; Performing edge detection processing on the stratum slice image to obtain an edge detection image of the stratum slice; The contours in the edge detection image of the stratigraphic slice are connected into a curve, and the curvature of the curve is calculated. The direction indicated by the line of maximum curvature of each curve is the main source direction of the earthquake foreset body.

2. The method for determining the direction of the main source using the edge of the earthquake foreset according to claim 1, characterized in that: The drilling sequence division and comparison are carried out in the research area of ​​the seismic foreset body, well-seismic calibration and seismic sequence interpretation are carried out, and an isochronous stratigraphic framework of the seismic foreset body is established to obtain a 3D seismic data volume constrained by the isochronous stratigraphic framework, including: Carry out drilling sequence division and comparison in the seismic foreset study area, and divide the target strata into third-order, fourth-order and fifth-order sequences by integrating cores, thin sections, well logging curves and well logging lithofacies combinations, and establish a drilling isochronous sequence stratigraphic division scheme; Based on the drilling isochronous sequence stratigraphic division scheme, the sequences were calibrated to the seismic data through well-seismic synthetic record calibration. Combined with the seismic reflection termination model, seismic sequence interpretation was carried out using 3D seismic data, and an isochronous sequence stratigraphic framework was constructed in the study area to obtain a 3D seismic data volume constrained by the isochronous stratigraphic framework.

3. The method for determining the direction of the main source using the edge of the earthquake foreset according to claim 1, characterized in that: The 3D seismic data volume with isochronous stratigraphic grid constraints is processed by frequency division and RGB fusion to obtain a frequency division fusion data volume, including: The three-dimensional seismic data volume is subjected to phase shift, frequency division and RGB fusion in sequence to obtain the frequency division fusion data volume.

4. The method for determining the direction of the main source using the edge of an earthquake foreset according to claim 3, characterized in that: Phase shift, frequency division and RGB fusion are performed on the 3D seismic data volume in sequence to obtain the frequency division fusion data volume, including: The 3D seismic data volume of the target area is processed by seismic phase shift using Geoscope software; Frequency parameters are selected and processed using Geoscope software on the phase-shifted seismic data volume, dividing the seismic data volume into high frequency, medium frequency, and low frequency. Frequency parameters are determined by calibration of well-seismic synthetic records. The three frequency division data volumes of high frequency, medium frequency and low frequency obtained by frequency division are fused by RGB frequency division through Geoscope software to obtain the frequency division fusion data volume, where R represents the low frequency data volume, G represents the medium frequency data volume, and B represents the high frequency data volume.

5. The method for determining the direction of the main source using the edge of the earthquake foreset according to claim 4, characterized in that: Frequency parameters are determined by calibration of well-seismic synthetic records, including: The frequency of the frequency-divided data body corresponding to the third-level sequence in the three-dimensional seismic data body is low frequency, the frequency of the frequency-divided data body corresponding to the fourth-level sequence is medium frequency, and the frequency of the frequency-divided data body corresponding to the fifth-level sequence is high frequency.

6. The method for determining the direction of the main source using the edge of an earthquake foreset according to claim 1, characterized in that: Perform stratigraphic slicing processing on the frequency-division fusion data volume to generate stratigraphic slice images of the seismic foreset volume, including: The stratigraphic slice image of the target area of ​​the seismic foreset is obtained by performing stratigraphic slice processing on the frequency-divided fusion data volume using Geoscope software. The stratigraphic slices were made using the equal-proportional stratigraphic slice method, with the top and bottom seismic sequences of the third-order sequence as the boundaries and a fixed sampling interval to produce equal-proportional stratigraphic slices.

7. The method for determining the direction of the main source using the edge of an earthquake foreset according to claim 1, characterized in that: Perform edge detection on the stratum slice image to obtain the detection results, including: Edge detection is performed using the Canny algorithm, which performs filtering, enhancement, suppression, and screening in sequence.

8. The method for determining the direction of the main source using the edge of the earthquake foreset according to claim 7, characterized in that: Edge detection is performed using the Canny algorithm, which performs filtering, enhancement, suppression, and screening in sequence, including: Gaussian filtering is used to filter the image; After the image is filtered, the Sobel operator is used to calculate the horizontal and vertical gradients respectively. The total gradient direction is calculated from the calculated horizontal and vertical gradients to obtain the gradient image. Perform non-maximum suppression on the gradient image, use non-maximum suppression to find the local maximum of the pixel point, set the grayscale value corresponding to the non-maximum value to 0, and obtain the suppressed image; A low threshold and a high threshold are selected for the suppressed image respectively, and points smaller than the low threshold are set to 0 as false edges, and points larger than the high threshold are set to 1 as strong edges to obtain a high threshold image; the edges in the high threshold image are linked into contours, and when the endpoint of the contour is reached, a point that meets the low threshold is searched among the eight neighborhood points of the breakpoint, and new edges are collected based on this point until the entire image is closed, thus obtaining an edge detection image of the stratum slice.

9. The method for determining the direction of the main source using the edge of an earthquake foreset body according to claim 1, characterized in that: The method further includes: if there are multiple earthquake foreset bodies, according to the edge detection image of the stratum slice, using the contour connection analysis in the edge detection result to obtain the development stages of the multiple foreset bodies.

10. The method for determining the direction of the main source using the edge of the earthquake foreset according to claim 1, characterized in that: It also includes: judging the distribution characteristics of the lithology and thickness of the foreset body through image color analysis based on the seismic foreset body stratum slice image, combined with the main source direction of the foreset body obtained by curvature calculation.

11. A system for determining the direction of the main source using the edge of an earthquake foreset, characterized in that: It includes a data body construction unit, a frequency division unit, a slicing unit, an edge detection unit and an analysis unit connected in sequence; The data volume construction unit is used to carry out drilling sequence division and comparison in the seismic foreset body study area, perform well-seismic calibration and seismic sequence interpretation, establish an isochronous stratigraphic framework for the seismic foreset body, and obtain a 3D seismic data volume constrained by the isochronous stratigraphic framework; The frequency division unit is used for frequency division and RGB fusion processing of the three-dimensional seismic data volume with isochronous stratigraphic grid constraints to obtain a frequency division fusion data volume; Slicing unit, used to perform stratigraphic slicing processing on the frequency-division fusion data volume to generate stratigraphic slice images of the seismic foreset volume; An edge detection unit is used to perform edge detection processing on the stratum slice image to obtain an edge detection image of the stratum slice; The analysis unit is used to connect the contours in the edge detection image of the stratigraphic slice into curves and calculate the curvature of the curves. The direction indicated by the line of maximum curvature of each curve is the main source direction of the earthquake foreset body.

12. An electronic device, characterized in that: The processor, the communication interface, the memory and the communication bus are connected to each other via the communication bus. a memory storing a computer program; The processor is configured to implement the method for determining the direction of a main provenance by using the edge of an earthquake precursor body as described in any one of claims 1 to 10 when executing the computer program stored in the memory.

13. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the method for determining the direction of a main provenance by using the edge of an earthquake precursor body according to any one of claims 1 to 10 is implemented.

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