Synthetic seismic record alignment and calibration method based on forced dynamic time warping

Abstract

The invention discloses a synthetic seismic record alignment and calibration method based on forced dynamic time warping, and belongs to the technical field of exploration, and the method comprises the following steps: S1, data preprocessing and seismic wavelet extraction; s2, geological constraints are set, and alignment and non-alignment points are determined; s3, generating a synthetic seismic record by using the reflection coefficient and the seismic wavelet; and S4, calculating an optimal alignment path by applying a forced dynamic time warping (FDTW) algorithm. According to the synthetic seismic record alignment and calibration method based on forced dynamic time warping, priori geological information can be fully fused, matching deviation caused by seismic record abnormity is effectively avoided, and the alignment precision between a synthetic record and an actual record is greatly improved.

Description

Technical Field

[0001] The present invention relates to the field of exploration technology, and in particular to a synthetic seismic record alignment and calibration method based on forced dynamic time warping. Background Art

[0002] Synthetic seismic records refer to seismic response records corresponding to actual seismic exploration data, which are simulated and generated through geological models and the principle of seismic wave propagation. Synthetic seismic records are essential for establishing accurate time-depth relationships between seismic data and well logging data. Their quality directly affects the accuracy of geological models and the prediction accuracy of oil and gas reservoirs.

[0003] In practical applications, due to the complexity of geological conditions, there is often a misalignment between the event axes of synthetic seismic records and actual seismic records. Although the traditional dynamic time warping (DTW) algorithm performs well in time series alignment, it faces some specific challenges when dealing with complex seismic record alignment. In particular, when the seismic records contain key reflection layers or other geological features that need to be strictly aligned or avoid alignment, traditional DTW is difficult to effectively process these complex prior constraint information, resulting in alignment results that cannot meet actual needs in some cases.

[0004] To solve this problem, the present invention proposes a synthetic seismic record alignment and calibration method based on forced dynamic time warping (FDTW). Summary of the invention

[0005] The purpose of the present invention is to provide a synthetic seismic record alignment and calibration method based on forced dynamic time warping, which can fully integrate prior geological information, effectively avoid matching deviations caused by seismic record anomalies, and greatly improve the alignment accuracy between synthetic records and actual records.

[0006] To achieve the above object, the present invention provides a synthetic seismic record alignment and calibration method based on forced dynamic time warping, comprising the following steps: S1. Data preprocessing and seismic wavelet extraction; S2, setting geological constraints and determining alignment and misalignment points; S3, generating synthetic seismic records using reflection coefficients and seismic wavelets; S4. Apply the forced dynamic time warping (FDTW) algorithm to calculate the optimal alignment path.

[0007] Preferably, in S1, conventional seismic processing technology is applied to pre-process the data of the target well, the well bypass seismic records related to the target well are extracted, a preliminary correspondence with the seismic data is established, and seismic wavelets are extracted or Ricker wavelets are generated therefrom.

[0008] Preferably, in S2, a geological model is established based on geological features and logging data, and the key reflection layers that need to be strictly aligned and abnormal area information that need to be avoided in actual seismic records are determined by combining the geological model and logging data, and mandatory alignment points and prohibited alignment points are set. Based on the established geological model, constraint conditions for the alignment process are set.

[0009] Preferably, the forced alignment points forcedpairs in S2 are a set of point pairs that must be strictly matched between the synthetic seismic record and the actual seismic record. In the path search process, the forced alignment points are used as the starting and ending points of the segments to ensure that the path must be forced to align the points. The path is expressed as: ; in, To force the number of alignment points, and Represent the indexes in the wellside channel sequence and synthetic channel sequence respectively; path It is decomposed into K+1 sub-segments, and the optimal path between the starting point and the end point is calculated independently for each sub-segment; Disable snap points is the set of point pairs that need to be completely excluded during the alignment process. For any point pair that is not allowed to be aligned , and its corresponding cost value Set to infinity, that is: .

[0010] Preferably, during the dynamic planning process, the prohibited alignment points will not be included in the optimal path, which specifically includes the following steps: S2.1, initialize the cumulative cost matrix and set all values ​​to infinity to exclude the default path; S2.2. Fill the cost matrix step by step according to the input data: Among them, for the starting point, if it does not belong to , then calculate its local cost and assign a value; For the first row and column, gradually accumulate the local costs and check whether it belongs to ; For other locations, the minimum cumulative cost is calculated using the dynamic programming formula, but skipping Prohibited points in .

[0011] Preferably, in S3, the reflection coefficient in the geological model is convolved with the extracted seismic wavelet to generate a preliminary synthetic seismic record, and the reflection coefficient and convolution model parameters are continuously adjusted so that the synthetic record preliminarily reflects the actual seismic response.

[0012] Preferably, the specific steps in S4 are as follows: S4.1, initialize FDTW algorithm parameters; S4.2, using the FDTW algorithm to align the synthetic seismic records and the actual seismic records segment by segment; S4.3, adjusting and updating the dynamic time warping DTW cost matrix based on the preset mandatory alignment points and prohibited alignment points; S4.4. Combine the generated alignment paths to accurately match the synthetic seismic records with the actual seismic records and generate the final alignment result dataset.

[0013] Therefore, the present invention adopts the above-mentioned synthetic seismic record alignment and calibration method based on forced dynamic time warping, which can fully integrate the prior geological information and introduce forced alignment points and prohibited alignment points on the basis of the traditional DTW algorithm. Compared with the traditional method, the FDTW algorithm can effectively avoid the matching deviation caused by seismic record anomalies while ensuring the accurate correspondence of key geological marks, thereby greatly improving the alignment accuracy between synthetic records and actual records.

[0014] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a flow chart of the synthetic seismic record alignment and calibration method based on forced dynamic time warping of the present invention; Figure 2 It is a flow chart of the FDTW algorithm subroutine of the synthetic seismic record alignment and calibration method based on forced dynamic time warping of the present invention; Figure 3 It is a schematic diagram of the cost matrix and optimal path of the FDTW algorithm when the constraints are turned on in the synthetic seismic record alignment and calibration method based on forced dynamic time warping of the present invention; Figure 4 It is a schematic diagram of the cost matrix and optimal path of the FDTW algorithm when the constraint condition is closed in the synthetic seismic record alignment and calibration method based on forced dynamic time warping of the present invention; Figure 5 It is a schematic diagram of synthetic seismic record generation based on the synthetic seismic record alignment and calibration method of the present invention for forced dynamic time warping; Figure 6 It is the cost matrix and optimal path diagram of the synthetic seismic record alignment and calibration method based on forced dynamic time warping of the present invention; Figure 7 It is a corresponding connection diagram of the synthetic seismic record alignment and calibration method based on forced dynamic time warping of the present invention and the sequence of synthetic tracks and well bypass tracks; Figure 8 This is a comparison diagram before and after the alignment of synthetic seismic records based on the synthetic seismic record alignment and calibration method of the present invention based on forced dynamic time warping. DETAILED DESCRIPTION

[0016] The technical solution of the present invention is further described below through the accompanying drawings and embodiments.

[0017] Unless otherwise defined, technical or scientific terms used in the present invention shall have the common meanings understood by one having ordinary skills in the field to which the present invention belongs.

[0018] Example like Figure 1 As shown, the present invention provides a synthetic seismic record alignment and calibration method based on forced dynamic time warping, taking the Dongying Formation stratum in Block C of Jizhong Depression as an example, comprising the following steps: S1. Data preprocessing and seismic wavelet extraction; Conventional seismic processing technology is used to pre-process the data for the target well to ensure data clarity and consistency. Data pre-processing includes but is not limited to denoising, static correction, removal of direct waves, frequency filtering and other steps to ensure data quality and consistency. The well-side channel seismic records related to the target well are extracted, a preliminary correspondence with the seismic data is established, and seismic wavelets are extracted or Ricker wavelets are generated from them to provide a basis for the subsequent generation of synthetic seismic records.

[0019] S2, setting geological constraints and determining alignment and misalignment points; A geological model is established based on geological features and logging data. Combined with the geological model and logging data, the key reflection layers that need to be strictly aligned in actual seismic records and the abnormal areas that need to be avoided or the discontinuous areas caused by logging noise are determined, and mandatory alignment points and prohibited alignment points are set. Based on the established geological model, constraints for the alignment process are set. Geological constraints include but are not limited to geological features such as stratigraphic interfaces, faults, and salt domes, which are determined through analysis of geological models and logging data.

[0020] Forced alignment points forcedpairs are a set of point pairs that must be strictly matched between synthetic seismic records and actual seismic records. During the path search process, the forced alignment points are used as the starting and ending points of the segments to ensure that the path must be forced to align with the points. The path is expressed as: ; in, To force the number of alignment points, and Represent the indexes in the wellside channel sequence and synthetic channel sequence respectively; path is decomposed into K+1 sub-segments, and each sub-segment independently calculates the optimal path between the starting point and the end point; Figure 3 and Figure 4 As shown, this piecewise solution ensures that the global path not only meets the continuity requirements of dynamic time warping, but also strictly follows the mandatory alignment constraints.

[0021] Disable snap points is the set of point pairs that need to be completely excluded during the alignment process. This is done by modifying the cumulative cost matrix. , and its corresponding cost value Set to infinity, that is: .

[0022] During dynamic planning, prohibited alignment points will not be included in the optimal path, such as Figure 3 and Figure 4 As shown, the path is effectively avoided. Specifically, the following steps are included: S2.1, initialize the cumulative cost matrix and set all values ​​to infinity to exclude the default path; S2.2. Fill the cost matrix step by step according to the input data: Among them, for the starting point, if it does not belong to , then calculate its local cost and assign a value; For the first row and column, gradually accumulate the local costs and check whether it belongs to ; For other locations, the minimum cumulative cost is calculated using the dynamic programming formula, but skipping middle prohibited points.

[0023] S3, generating synthetic seismic records using reflection coefficients and seismic wavelets; The reflection coefficient in the geological model is convolved with the extracted seismic wavelet to generate a preliminary synthetic seismic record. The reflection coefficient and convolution model parameters are continuously adjusted to gradually optimize the matching effect between the two, so that the synthetic record preliminarily reflects the actual seismic response, laying the foundation for further alignment and calibration.

[0024] Figure 5 As shown, a schematic diagram of synthetic seismic record generation by the synthetic seismic record alignment and calibration method described in an embodiment of the present invention shows how to generate a synthetic seismic record by convolving the reflection coefficient in the geological model with the extracted seismic wavelet.

[0025] S4, applying the forced dynamic time warping FDTW algorithm to calculate the optimal alignment path; Figure 2 The specific steps are as follows: S4.1. Initialize FDTW algorithm parameters, including forced alignment points (forced_pairs), prohibited alignment points (must_not_pairs), and window size (window_size). These parameters ensure that the alignment path achieves optimal matching while complying with geological constraints.

[0026] S4.2. Use the FDTW algorithm to align the synthetic seismic records and the actual seismic records segment by segment. First, perform dynamic time warping (DTW) calculation on the path from the starting point to the first forced alignment point, then independently calculate the path between each forced alignment point in turn, and finally align the path from the last forced alignment point to the end point.

[0027] S4.3. Based on the preset mandatory alignment points and prohibited alignment points, the dynamic time warping DTW cost matrix is ​​adjusted and updated; by dynamically calculating the minimum cost of the path, the FDTW algorithm generates the optimal alignment path and outputs a matching coordinate point sequence.

[0028] S4.4. Combine the generated alignment paths to accurately match the synthetic seismic records with the actual seismic records and generate the final alignment result dataset.

[0029] Figure 6 As shown, the cost matrix and optimal path diagram of the synthetic seismic record alignment and calibration method described in the embodiment of the present invention show the distribution of the cost matrix and the optimal path. The figure clearly presents the structure of the cost matrix and the selection process of the optimal path, indicating that the present invention can effectively integrate the prior constraints under complex geological conditions and achieve high-precision alignment.

[0030] Figure 7 As shown, the synthetic seismic record alignment and calibration method of the embodiment of the present invention is a corresponding connection diagram of the synthetic track and the well bypass track sequence, which shows the corresponding connection relationship between the synthetic seismic record and the well bypass track seismic record. This figure clearly reflects how the alignment path accurately matches the key points in the two sequences, providing a reliable basis for the subsequent optimization of the geological model and time-depth calibration.

[0031] Figure 8 As shown, the synthetic seismic record alignment and calibration method described in the embodiment of the present invention is a comparison diagram of synthetic seismic records before and after alignment, showing the comparison effect before and after the synthetic seismic record alignment. The figure clearly reflects how the alignment path is optimized after the introduction of mandatory constraints, so that the key points of the synthetic seismic record and the actual seismic record are more accurately matched, thereby significantly improving the alignment accuracy and the reliability of the geological model.

[0032] Therefore, the present invention adopts the above-mentioned synthetic seismic record alignment and calibration method based on forced dynamic time warping, which can fully integrate the prior geological information, effectively avoid the matching deviation caused by seismic record anomalies, and greatly improve the alignment accuracy between synthetic records and actual records. This method optimizes the alignment path of seismic records by introducing constraints such as prior forced alignment points and prohibited alignment points in traditional DTW. This improvement not only effectively solves the alignment problem under complex geological conditions, but also improves the accuracy and stability of alignment, thereby providing more reliable support for the refinement of geological models and the accuracy of oil and gas reservoir prediction.

[0033] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.

Claims

1. A synthetic seismic record alignment and calibration method based on forced dynamic time warping, characterized by: The following steps are involved: S1. Data preprocessing and seismic wavelet extraction; S2, setting geological constraints and determining alignment and misalignment points; S3, generating synthetic seismic records using reflection coefficients and seismic wavelets; S4. Apply the forced dynamic time warping (FDTW) algorithm to calculate the optimal alignment path.

2. The synthetic seismic record alignment and calibration method based on forced dynamic time warping according to claim 1, characterized in that: In S1, conventional seismic processing technology is applied to preprocess the data of the target well, extract the well side channel seismic records related to the target well, establish a preliminary correspondence with the seismic data, and extract seismic wavelets or generate Ricker wavelets from them.

3. The synthetic seismic record alignment and calibration method based on forced dynamic time warping according to claim 1, characterized in that: In S2, a geological model is established based on geological features and logging data. The key reflection layers that need to be strictly aligned and the abnormal area information that needs to be avoided in actual seismic records are determined by combining the geological model and logging data. Mandatory alignment points and prohibited alignment points are set. On the basis of the established geological model, constraint conditions for the alignment process are set.

4. The synthetic seismic record alignment and calibration method based on forced dynamic time warping according to claim 3, characterized in that: The forced alignment points in S2 are the set of point pairs that must be strictly matched between the synthetic seismic records and the actual seismic records. In the path search process, the forced alignment points are used as the starting and ending points of the segments to ensure that the path must be forced to align with the points. The path is expressed as: ； in, To force the number of alignment points, and Represent the indexes in the wellside channel sequence and synthetic channel sequence respectively; path It is decomposed into K+1 sub-segments, and the optimal path between the starting point and the end point is calculated independently for each sub-segment; Disable snap points is the set of point pairs that need to be completely excluded during the alignment process. For any point pair that is not allowed to be aligned , and its corresponding cost value Set to infinity, that is: 。 5. The synthetic seismic record alignment and calibration method based on forced dynamic time warping according to claim 4, characterized in that: During the dynamic planning process, the prohibited alignment points will not be included in the optimal path, which includes the following steps: S2.1, initialize the cumulative cost matrix, set all values ​​to infinity to exclude the default path; S2.

2. Fill the cost matrix step by step according to the input data: Among them, for the starting point, if it does not belong to , then calculate its local cost and assign a value; For the first row and column, gradually accumulate the local costs and check whether it belongs to ; For other locations, the minimum cumulative cost is calculated using the dynamic programming formula, but skipping Prohibited points in .

6. The synthetic seismic record alignment and calibration method based on forced dynamic time warping according to claim 1, characterized in that: In S3, the reflection coefficient in the geological model is convolved with the extracted seismic wavelet to generate a preliminary synthetic seismic record. The reflection coefficient and convolution model parameters are continuously adjusted so that the synthetic record preliminarily reflects the actual seismic response.

7. The synthetic seismic record alignment and calibration method based on forced dynamic time warping according to claim 1, characterized in that: The specific steps in S4 are as follows: S4.1, initialize FDTW algorithm parameters; S4.2, using the FDTW algorithm to align the synthetic seismic records and the actual seismic records segment by segment; S4.3, adjusting and updating the dynamic time warping DTW cost matrix based on the preset mandatory alignment points and prohibited alignment points; S4.

4. Combine the generated alignment paths to accurately match the synthetic seismic records with the actual seismic records and generate the final alignment result dataset.

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