Method for analyzing basin evolution by using seismic data to calculate flip-tilt coefficient

Abstract

The invention provides a method for analyzing basin evolution by calculating a lift-skew coefficient by using seismic data, which comprises the following steps of: acquiring seismic section data of a research area, identifying a seismic reflection interface on a seismic section, and further dividing a sequence unit; performing time-depth conversion on the seismic section to obtain a depth domain seismic section; based on the depth domain seismic section, measuring the vertical height difference and the real length of each sequence interface between sequence units; based on the vertical height difference and the real length of each sequence interface, respectively calculating the lifting and inclining height difference and the lifting and inclining width difference of each sequence unit; and calculating a lift-tilt coefficient according to the lift-tilt height difference and the lift-tilt width difference of each sequence unit, and representing the basin evolution process according to the change of the lift-tilt coefficient. And the quantitative characterization of the basin evolution in the complex fault region is realized.

Description

Technical Field

[0001] This invention relates to the technical field of sedimentary basin analysis, and more particularly to a method for calculating tilt coefficients using seismic data. Background Technology

[0002] The analysis of sedimentary basin evolution is a crucial aspect of oil and gas exploration and development. In some complex fault zones, the influence of faults leads to faulting or compression deformation within the old and new strata of the basin, significantly hindering the analysis of sedimentary basin evolution.

[0003] The evolution of sedimentary basins is significantly influenced by the intensity of fault activity. During periods of intense faulting, the stratigraphic characteristics formed within the basin become more complex, with significant changes in stratigraphic structure, lithology, and physical properties of the sediments. Previous explanations for the tectonic formation mechanism of the Bohai Bay Basin fall into two main categories: extensional-strike-slip and extensional-pull-apart. The former posits that the Bohai Bay Basin was formed by the superposition of extensional processes and subsequent strike-slip tectonic activity, while the latter suggests that it is a composite extensional-pull-apart basin formed by the superposition of early extensional processes and later strike-slip pull-apart activities. Furthermore, among the many factors controlling the evolution of sedimentary basins, tectonic activity can be considered the most crucial. Firstly, tectonic activity can trigger clastic sediment reactivation and volcanic intrusion; secondly, it can provide depositional space and sites.

[0004] The invention patent with authorization announcement number CN109541684B discloses a method for analyzing the stratigraphic evolution of sedimentary basins. The method involves the following steps: obtaining a seismic profile of the target sedimentary basin; and determining the evolutionary patterns between two adjacent, globally distributed strata based on the position of the seismic interpretation axes of sand bodies relative to the lake basin in the seismic profile. The globally distributed strata refer to strata developed throughout the entire basin and possessing clear geological age characteristics. The sand bodies between the two globally distributed strata are not globally distributed: when the seismic interpretation axis of the upper sand body moves relative to the seismic interpretation axis of the lower sand body towards the center of the lake basin, the upper sand body was deposited during a lake basin shrinkage process. However, the evolution of sedimentary basins is often difficult to characterize quantitatively; therefore, current research primarily uses qualitative descriptions to analyze the evolutionary process of sedimentary basins. Summary of the Invention

[0005] To address the technical problem of the difficulty in characterizing the evolution process of basins in complex fault regions, this invention proposes a method for analyzing basin evolution by calculating tilt coefficients using seismic data. By calculating tilt coefficients, a quantitative characterization of basin evolution in complex fault regions is achieved, solving the core problem that traditional techniques mainly rely on qualitative descriptions and cannot accurately quantify the degree of evolution.

[0006] To achieve the above objectives, the technical solution of the present invention is implemented as follows:

[0007] A method for analyzing basin evolution by calculating tilt coefficients using seismic data includes the following steps:

[0008] S1: Obtain seismic profile data of the study area, identify seismic reflection interfaces on the seismic profiles, and then divide them into sequence units;

[0009] S2: Perform time-depth conversion on the seismic profile to obtain a depth-domain seismic profile;

[0010] S3: Based on the depth domain seismic profile, measure the vertical height difference and true length of each sequence interface between sequence units;

[0011] S4: Calculate the tilting height difference and tilting width difference of each sequence unit based on the vertical height difference and actual length of each sequence interface;

[0012] S5: Calculate the tilt coefficient based on the tilt height difference and tilt width difference of each sequence unit, and characterize the basin evolution process based on the change of the tilt coefficient.

[0013] Furthermore, the identification of seismic reflection interfaces on the seismic profile includes:

[0014] The reflection characteristics of seismic reflection interfaces are found on the seismic profile, including the seismic reflection termination relationship and the differences in seismic facies characteristics in sedimentary cycles. Based on the seismic reflection termination relationship and the differences in seismic facies characteristics in sedimentary cycles, seismic reflection interfaces are identified on the seismic profile. All seismic reflection interfaces that meet the reflection characteristics are marked as sequence interfaces, and sequence units are divided according to the sequence interfaces.

[0015] Furthermore, the earthquake reflection termination relationship includes at least one of the following: overshoot, undershoot, top overshoot, and cut-off;

[0016] The differences in seismic facies characteristics in the sedimentary cycles include upper strata exhibiting amplitudes less than the threshold, chaotic reflections, or blank reflections; and lower strata exhibiting amplitudes greater than or equal to the threshold, continuous reflections, and progradational reflections.

[0017] Furthermore, the time-depth conversion of the seismic profile includes:

[0018] For scenarios with abundant data and relevant drilling / logging data, a velocity model is established based on the seismic profile in the time domain and the drilling / logging data. The velocity model is then used to transform the seismic profile data from the time domain to the depth domain.

[0019] For scenarios lacking data, where relevant drilling / logging data is unavailable, a custom velocity function is used with relevant well depth and actual vertical depth data of TVD to convert seismic profile data from the time domain to the depth domain.

[0020] Furthermore, the method for establishing a velocity model based on time-domain seismic profiles and drilling / logging data is as follows: Preprocess the time-domain seismic profiles and drilling / logging data; calculate the time-depth relationship curve using sonic logging data from the drilling / logging data; compare the time-depth relationship curve segment by segment with the preprocessed time-domain seismic profile to complete layer calibration and obtain the time-domain seismic profile with completed layer calibration; conduct velocity spectrum analysis on the time-domain seismic profile with completed layer calibration; establish a two-dimensional initial velocity model based on the optimal velocity values ​​at each depth point and perform preliminary corrections; use the corrected initial velocity model to perform time-depth conversion on the preprocessed time-domain seismic profile to obtain a preliminary depth-domain seismic profile, and compare and verify it with the drilling / logging data to obtain the optimized final velocity model;

[0021] The method for customizing the velocity function using relevant well depth and TVD true vertical depth data is as follows: Obtain the original well depth dataset, the original TVD true vertical depth dataset, and the basic geological data of the study area, and perform preprocessing to obtain the well depth-TVD associated dataset; group the well depth-TVD associated dataset according to the stratigraphic division criteria of the seismic profile data, and segment each group by depth, calculating the average velocity of each depth segment within each group to obtain an average velocity table for each geological group; pair the depth and average velocity of all depth segments within the same group to form depth-velocity data pairs, and select a fitting function based on the data distribution to perform parameter fitting, obtaining the fitted velocity function; use the fitted velocity function to perform time-depth conversion on the time-domain seismic profile to obtain a preliminary depth-domain seismic profile, and compare and verify it with drilling / logging data to obtain the optimized final velocity function.

[0022] Furthermore, the measurement of the vertical height difference between each sequence interface includes:

[0023] In the selected typical seismic profile, the research scope is determined, and a coordinate system is established with the fault start and end points as references, the vertical axis representing the stratum depth and the horizontal axis representing the stratum length.

[0024] In the coordinate system, determine the intersection points between each sequence boundary and the fault and the basement surface, and determine the coordinates of the intersection point A between each sequence boundary and the fault, and the coordinates of the intersection point B between the sequence boundary and the basement surface. Based on the ordinate of the intersection point A between the sequence boundary and the fault, determine the distance from the intersection point A to the horizontal axis. The distance from the intersection point B of the sequence boundary and the basal surface to the horizontal axis is determined based on the ordinate of the intersection point B. According to distance and distance Calculate the vertical height difference of the sequence interface , where i is the sequence number of the layer interface.

[0025] Furthermore, the measurement of the true length of each layer sequence interface includes:

[0026] Each sequence interface is divided into j small regions using the finite element method, and each small region is an approximate straight line segment.

[0027] Measure the vertical height of each small area. and horizontal length The Pythagorean theorem is used to calculate the true length of each small region. ;

[0028] The true length of each sequence interface is obtained by summing the values ​​of each small region. .

[0029] Furthermore, step S4 includes:

[0030] Calculate the tilting height difference based on the vertical height difference of each sequence interface. ;

[0031] The tilt width difference is calculated based on the actual length of each layer interface. .

[0032] Furthermore, the method for calculating the tilting coefficient based on the tilting height difference and tilting width difference of each sequence unit is as follows:

[0033] .

[0034] Furthermore, the changes in the tilt coefficient characterize the basin evolution process, including:

[0035] The rate of increase in the lateral area of ​​the basin is slow;

[0036] The rate of increase in the lateral area of ​​the basin is moderate;

[0037] : The rate of increase of the horizontal area of ​​the basin.

[0038] The beneficial effects of this invention are as follows:

[0039] This invention establishes a standardized five-step process—sequence stratigraphy, time-depth conversion, parameter measurement, difference calculation, and coefficient analysis—to achieve quantitative characterization of basin evolution in complex fault zones. This solves the core problem of traditional techniques, which primarily rely on qualitative descriptions and cannot accurately quantify the degree of evolution. Simultaneously, it improves the repeatability and objectivity of the method, avoiding errors caused by subjective human judgment. It can be applied to oilfield exploration to more accurately identify corresponding sequence units where significant changes have occurred in sedimentary basins, providing an evaluation reference for oil and gas exploration and development in the study area. Attached Figure Description

[0040] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0041] Figure 1 This is a flowchart of the tilt coefficient calculation method according to an embodiment of the present invention.

[0042] Figure 2 This is a typical seismic profile and a schematic diagram of the corresponding sequence interface identification and sequence unit division in an embodiment of the present invention.

[0043] Figure 3 This is a schematic diagram illustrating the method for calculating the height difference between the interfaces of each layer in an embodiment of the present invention.

[0044] Figure 4 This is a schematic diagram illustrating the method for calculating the true length of the layer sequence interface according to an embodiment of the present invention. Detailed Implementation

[0045] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0046] A method for analyzing basin evolution by calculating tilt coefficients using seismic data, such as... Figure 1 As shown, the steps include:

[0047] S1: Obtain seismic profile data of the study area, identify seismic reflection interfaces on the seismic profiles, and then divide them into sequence units.

[0048] In this embodiment of the application, identifying seismic reflection interfaces on seismic profiles includes:

[0049] The reflection characteristics of seismic reflection interfaces on seismic profiles are used as identification markers, including seismic reflection termination relationships and differences in seismic facies characteristics within sedimentary cycles. Based on these seismic reflection termination relationships and differences in seismic facies characteristics within sedimentary cycles, seismic reflection interfaces are identified on the seismic profiles. All seismic reflection interfaces that meet the identification markers are marked as sequence boundaries, and sequence units are delineated based on these sequence boundaries. (See figure).

[0050] The earthquake reflection termination relationship includes at least one of the following: overshoot, undershoot, topshoot, and cut-off.

[0051] The differences in seismic facies characteristics within the sedimentary cycles include weak amplitude, disordered, or blank reflections in the upper strata; and moderate to strong amplitude, continuous, and progradational reflections in the lower strata; among which, those less than the threshold... The amplitude is weak and is greater than or equal to the threshold. The amplitude is medium to strong.

[0052] S2: Perform time-depth conversion on the seismic profile to obtain a depth-domain seismic profile. Time-depth conversion of seismic data requires using drilling and well logging data to establish a one-to-one correspondence between the time-domain depth and the actual depth in the depth domain.

[0053] In this embodiment of the application, time-depth conversion of the seismic profile includes:

[0054] For scenarios with abundant data and relevant drilling / logging data, a velocity model is established based on the seismic profile in the time domain and the drilling / logging data. The velocity model is then used to transform the seismic profile data from the time domain to the depth domain.

[0055] The method for establishing a velocity model based on time-domain seismic profiles and drilling / logging data is as follows:

[0056] First, the original time-domain seismic profiles are preprocessed with denoising and gain restoration, while drilling / logging data are organized to ensure their completeness and accuracy.

[0057] Furthermore, the time-depth relationship curve is calculated using sonic logging data from drilling / logging data. The time-depth relationship curve is then compared segment by segment with the preprocessed time-domain seismic profile to complete the layer calibration and obtain the time-domain seismic profile with completed layer calibration.

[0058] Furthermore, velocity spectrum analysis was conducted on the time-domain seismic profiles with completed stratigraphic calibration to determine the optimal velocity values ​​at different depths within each geological stratigraphic level. Based on the optimal velocity values ​​at each depth, combined with regional geological knowledge (i.e., known geological background information) and stratigraphic calibration information, a two-dimensional initial velocity model was established. Velocity grids were divided according to geological stratigraphic levels, and a corresponding velocity value was assigned to each grid node. Anomaly detection was performed on the initial velocity model to identify anomalous regions with abrupt velocity changes and contradictions with geological knowledge. Based on geological patterns and drilling / logging data, the velocity values ​​in the anomalous regions were locally corrected.

[0059] Furthermore, using the modified initial velocity model, the preprocessed time-domain seismic profile is converted to time-depth to obtain a preliminary depth-domain seismic profile. Key parameters such as formation depth and layer thickness in the preliminary depth-domain seismic profile are compared and verified point by point with the actual vertical depth (TVD) and formation thickness data in the drilling / logging data, and a deviation allowable threshold is set. If the comparison result exceeds the allowable threshold, the velocity value of the corresponding grid node in the initial velocity model is corrected in reverse, and the time-depth conversion and comparison verification process is repeated until the deviation between the model conversion result and the drilling / logging data meets the requirements. The output is the optimized final velocity model.

[0060] The lateral length range of each sequence unit is The depth range is The final velocity model expression is:

[0061]

[0062] in, This is the final velocity model.

[0063] Through formula Inverse integration can transform seismic profile data from the time domain to the depth domain.

[0064] For scenarios lacking data, where relevant drilling / logging data is unavailable, a custom velocity function is used to convert seismic profile data from the time domain to the depth domain using relevant well depth and true vertical depth (TVD) data.

[0065] The method for customizing the velocity function using relevant well depth and true vertical depth (TVD) data is as follows:

[0066] First, obtain the original well depth dataset, the original true vertical depth (TVD) dataset, and the basic geological data of the study area. Correlate the well depth and TVD data, remove logically erroneous data, and combine the basic geological data to remove outliers and fill in missing key information; obtain the well depth-TVD correlated dataset.

[0067] Furthermore, based on the stratigraphic classification criteria of seismic profile data, the well depth-TVD associated dataset is grouped, and each group is segmented by depth. The average velocity of each depth segment within each group is calculated to obtain the average velocity table for each geological group.

[0068] Furthermore, the depth of all depth segments within the same group is... Peaceful End Speed Pairing data to form depth-velocity pairs, and selecting mathematical methods based on data distribution characteristics, linear fitting is used for shallow depths (0-2000m). For medium-deep sections (greater than 2000m), a quadratic polynomial fitting method is used. The least squares method is used for parameter fitting, and the goodness of fit is required. ,like Adjust the fitting model or merge adjacent segments and recalculate;

[0069] Furthermore, a well-fitted velocity function is used on the original seismic profile data. By inverse integral Calculate the true depth of each well point to generate a preliminary depth domain seismic profile. Compare this profile with the true TVD in the well depth-TVD data to calculate the deviation. If the deviation of 90% of the well points is less than 5%, then the final velocity function is obtained.

[0070] This invention achieves adaptation to study areas with different data abundance by designing a velocity model conversion and a custom velocity function conversion strategy for different scenarios. It not only meets the efficient conversion needs of areas with abundant drilling / logging data, but also solves the problem of time-depth conversion not being possible in areas with scarce data, significantly improving the universality of the method.

[0071] S3: Based on the depth domain seismic profile, measure the vertical height difference and true length of each sequence interface between sequence units.

[0072] In this embodiment of the application, measuring the vertical height difference between each layer interface includes:

[0073] In the selected typical seismic profile, the research scope is determined, with the fault (red) start and end points as references, the vertical axis representing the stratum depth and the horizontal axis representing the stratum length, and a coordinate system is established;

[0074] In the coordinate system, determine the intersection points between the sequence boundary and the fault and the basement surface, respectively. Determine the coordinates of the intersection point A between the sequence boundary and the fault, and the coordinates of the intersection point B between the sequence boundary and the basement surface. Based on the ordinate of the intersection point A between the sequence boundary and the fault, determine the distance from the intersection point A between the sequence boundary and the fault to the horizontal axis. The distance from the intersection point B of the sequence boundary and the basal surface to the horizontal axis is determined based on the ordinate of the intersection point B. According to distance and distance Calculate the vertical height difference of the sequence interface , where i is the sequence number of the layer interface.

[0075] In this embodiment of the application, the true length of the sequence interface is difficult to measure. Since the interface shape is not a regular curve or straight line, the finite element method is used to divide the complex sequence interface into several simple small regions. The vertical height and horizontal length of each small region are measured respectively, and then the true length of the sequence interface of each small region is calculated.

[0076] The measurement of the true length of each layer sequence interface includes:

[0077] Each sequence interface is divided into j small regions using the finite element method, and each small region is an approximate straight line segment.

[0078] Measure the vertical height of each small area. and horizontal length The Pythagorean theorem is used to calculate the true length of each small region. ;

[0079] The true length of each sequence interface is obtained by summing the values ​​of each small region. .

[0080] This invention uses the finite element method to decompose irregular sequence interfaces and combines it with a unified coordinate system reference measurement parameters to accurately obtain the vertical height difference and true length of the sequence interface. This solves the technical pain point of difficulty in measuring key parameters of complex interface shapes and provides a reliable data foundation for subsequent quantitative calculations.

[0081] S4: Calculate the tilting height difference and tilting width difference of each sequence unit based on the vertical height difference and actual length of each sequence interface.

[0082] In this embodiment of the application, calculating the tilting height difference based on the vertical height difference of each layer interface includes:

[0083] ;

[0084] in, This refers to the height difference of the tilt.

[0085] In this embodiment of the application, calculating the tilt width difference based on the actual length of each layer interface includes:

[0086] ;

[0087] in, This refers to the difference in tilt width.

[0088] S5: Calculate the tilt coefficient based on the tilt height difference and tilt width difference of each sequence unit, and characterize the basin evolution process based on the change of the tilt coefficient.

[0089] In this embodiment of the application, the tilting coefficient is:

[0090] ;

[0091] Based on the changes in the tilt coefficient, the basin evolution process can be characterized by:

[0092] The rate of increase in the lateral area of ​​the basin is slow;

[0093] The rate of increase in the lateral area of ​​the basin is moderate;

[0094] : The rate of increase of the horizontal area of ​​the basin.

[0095] This invention, through the quantitative comparison characteristics of tilt coefficients, enables horizontal and vertical comparisons of the evolutionary degrees of different study areas and sequence units, breaking the limitations of traditional qualitative descriptions that cannot compare across regions / strata, and providing a unified evaluation standard for sedimentary basin geological research. By innovatively classifying and characterizing based on tilt coefficients, it achieves a quantitative classification of basin evolution and expansion rates, enabling precise location of significant periods of change during the evolution process, and providing direct evidence for identifying favorable sequence units for hydrocarbon accumulation. Figure 2 The diagram illustrates a typical seismic profile and corresponding sequence boundary identification and sequence unit division according to an embodiment of the present invention. Seismic sequences are reflections of sedimentary sequences on seismic profiles. Sequence boundaries record rich geological information such as sedimentary environment, sediment supply, sea-level changes, and tectonic activity; abrupt lithological changes typically occur above and below these boundaries. Sequence boundaries can be identified and seismic sequences divided based on seismic reflection termination types (e.g., overlap, underlap, toplap, and truncation). When seismic profiles lack overlap features and truncation phenomena reflecting sea-level changes, sequence boundaries can be identified using differences in seismic facies characteristics between deep-water sedimentary cycles. A typical seismic profile in the Enping Depression was selected, and 10 sequence boundaries were identified based on seismic reflection termination relationships and differences in seismic facies characteristics. The sedimentary strata were then divided into 9 sequence units; additionally, obvious faults were also identified in the seismic profile.

[0096] Figure 3 This is a schematic diagram illustrating the calculation method for the height difference between sequence interfaces in an embodiment of the present invention. The specific calculation method is as follows: In a typical seismic profile, based on... Figure 2 The sequence boundaries identified in the stratigraphy are used, with the basement boundary and fault as the basin's constrained boundaries. The height differences of each sequence boundary are calculated. Taking boundary SB2 as an example, the coordinates of the intersection points of the boundary with the fault and basement boundaries are first determined, and the vertical heights are obtained respectively. and Then, the vertical height difference of interface SB2 is calculated. Similarly, the vertical height difference of other sequence interfaces is obtained, i.e. (i is the number of hierarchical interfaces).

[0097] Figure 4 This is a schematic diagram illustrating the method for calculating the true length of the sequence interface according to an embodiment of the present invention. The specific calculation method is as follows: Calculating the true planar width of the sequence interface is quite difficult because it is not a regular curve with regular characteristics, and existing formulas cannot be directly applied. Therefore, the complex sequence interface is divided into several simple small regions using the finite element method. Within each small region, the sequence interface is approximately linear. By determining the coordinates of the two endpoints of the sequence interface within a small region, the vertical height h and the horizontal length s can be obtained, thus yielding the true length of the sequence interface within that small region. Then the true length of the sequence interface within the j-th subregion is Finally, the actual lengths of the sequence interfaces obtained in several small regions are summed to obtain the actual width of the sequence interface itself. ,Right now Similarly, the actual lengths of other layer interfaces are obtained. The parameters i and j are variable values. The former is determined by the number of sequence interfaces, and the latter is determined by the number of small regions divided by a single sequence interface. There is no absolute relationship between the two.

[0098] pass Figure 3 and Figure 4 Obtain the vertical height difference of each sequence interface. and actual width Then, the tilt height difference of each sequence unit is calculated. ),Right now and the difference in tilt width ( ),Right now Ultimately, the tilt coefficient, which can quantitatively characterize the evolution process of sedimentary basins, is obtained. ),Right now .

[0099] Table 1 presents statistical data on parameters such as tilt height difference, tilt width difference, and tilt coefficient in embodiments of the present invention. More than half of the sequence units have a tilt width difference greater than 1000m, indicating significant variations between the top and bottom interfaces of each sequence. This suggests that the top interface exhibited obvious expansion characteristics during basin development, further reflecting significant movement of the faults controlling the depression development during these periods, possibly involving horizontal subsidence and extension. The tilt coefficient can be categorized into three types: 0.0... <Di<0.1;0.1<Di<0.3;Di> 0.3. These represent the rates of increase in the basin's lateral area: slow, relatively fast, and fast, respectively. The magnitude of the tilt coefficient reflects either a large sequence height difference or a small sequence width value.

[0100] Statistical analysis of the tilt coefficients of each sequence unit revealed a significant change in the tilt coefficient of sequence unit 4 compared to the two sequence units above and below it. This indicates that the sedimentary basin where this sequence unit developed underwent substantial changes (possibly due to significant tectonic activity, climate change, or global sea-level fluctuations), resulting in a marked change in the tilt coefficient. Based on this, the periods during which external factors influenced the development and evolution of the sedimentary basin can be directly identified. This allows for a focused analysis of the sequence unit, examining the vertical stacking structure of the sedimentary strata within the basin during this period, as well as the structure of the sedimentary strata themselves (such as chaotic structures or well-continuous parallel-subparallel structures). This analysis provides an evaluation reference for the analysis of hydrocarbon reservoirs.

[0101] Table 1. Statistical data of various parameters such as tilt height difference, tilt width difference, and tilt coefficient.

[0102]

[0103] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for analyzing basin evolution by calculating tilt coefficients using seismic data, characterized in that, Including the following steps: S1: Obtain seismic profile data of the study area, identify seismic reflection interfaces on the seismic profiles, and then divide them into sequence units; S2: Perform time-depth conversion on the seismic profile to obtain a depth-domain seismic profile; S3: Based on the depth domain seismic profile, measure the vertical height difference and true length of each sequence interface between sequence units; S4: Calculate the tilting height difference and tilting width difference of each sequence unit based on the vertical height difference and actual length of each sequence interface; S5: Calculate the tilt coefficient based on the tilt height difference and tilt width difference of each sequence unit, and characterize the basin evolution process based on the change of the tilt coefficient.

2. The method for calculating tilt-up coefficient to analyze basin evolution using seismic data according to claim 1, characterized in that, The identification of seismic reflection interfaces on seismic profiles includes: The reflection characteristics of seismic reflection interfaces are found on the seismic profile, including the seismic reflection termination relationship and the differences in seismic facies characteristics in sedimentary cycles. Based on the seismic reflection termination relationship and the differences in seismic facies characteristics in sedimentary cycles, seismic reflection interfaces are identified on the seismic profile. All seismic reflection interfaces that meet the reflection characteristics are marked as sequence interfaces, and sequence units are divided according to the sequence interfaces.

3. The method for calculating tilt-up coefficient to analyze basin evolution using seismic data according to claim 2, characterized in that, The earthquake reflection termination relationship includes at least one of the following: overshoot, undershoot, top overshoot, and cut-off; The differences in seismic facies characteristics in the sedimentary cycles include upper strata exhibiting amplitudes less than the threshold, chaotic reflections, or blank reflections; and lower strata exhibiting amplitudes greater than or equal to the threshold, continuous reflections, and progradational reflections.

4. The method for analyzing basin evolution using tilt coefficients based on seismic data according to any one of claims 1-3, characterized in that, The time-depth conversion of the seismic profile includes: For scenarios with abundant data and relevant drilling / logging data, a velocity model is established based on the seismic profile in the time domain and the drilling / logging data. The velocity model is then used to transform the seismic profile data from the time domain to the depth domain. For scenarios lacking data, where relevant drilling / logging data is unavailable, a custom velocity function is used with relevant well depth and actual vertical depth data of TVD to convert seismic profile data from the time domain to the depth domain.

5. The method for calculating tilt coefficients and analyzing basin evolution using seismic data according to claim 4, characterized in that, The method for establishing a velocity model based on time-domain seismic profiles and drilling / logging data is as follows: Preprocess the time-domain seismic profiles and drilling / logging data; calculate the time-depth relationship curve using sonic logging data from the drilling / logging data; compare the time-depth relationship curve segment by segment with the preprocessed time-domain seismic profile to complete layer calibration and obtain the time-domain seismic profile with completed layer calibration; conduct velocity spectrum analysis on the time-domain seismic profile with completed layer calibration; establish a two-dimensional initial velocity model based on the optimal velocity values ​​at each depth point and perform preliminary corrections; use the corrected initial velocity model to perform time-depth conversion on the preprocessed time-domain seismic profile to obtain a preliminary depth-domain seismic profile, and compare and verify it with the drilling / logging data to obtain the optimized final velocity model. The method for customizing the velocity function using relevant well depth and TVD true vertical depth data is as follows: Obtain the original well depth dataset, the original TVD true vertical depth dataset, and the basic geological data of the study area, and perform preprocessing to obtain the well depth-TVD associated dataset; group the well depth-TVD associated dataset according to the stratigraphic division criteria of the seismic profile data, and segment each group by depth, calculating the average velocity of each depth segment within each group to obtain an average velocity table for each geological group; pair the depth and average velocity of all depth segments within the same group to form depth-velocity data pairs, and select a fitting function based on the data distribution to perform parameter fitting, obtaining the fitted velocity function; use the fitted velocity function to perform time-depth conversion on the time-domain seismic profile to obtain a preliminary depth-domain seismic profile, and compare and verify it with drilling / logging data to obtain the optimized final velocity function.

6. The method for calculating tilt coefficients and analyzing basin evolution using seismic data according to claim 5, characterized in that, The measurement of the vertical height difference between each sequence interface includes: In the selected typical seismic profile, the research scope is determined, and a coordinate system is established with the fault start and end points as references, the vertical axis representing the stratum depth and the horizontal axis representing the stratum length. In the coordinate system, determine the intersection points between each sequence boundary and the fault and the basement surface, and determine the coordinates of the intersection point A between each sequence boundary and the fault, and the coordinates of the intersection point B between the sequence boundary and the basement surface. Based on the ordinate of the intersection point A between the sequence boundary and the fault, determine the distance from the intersection point A to the horizontal axis. The distance from the intersection point B of the sequence boundary and the basal surface to the horizontal axis is determined based on the ordinate of the intersection point B. According to distance and distance Calculate the vertical height difference of the sequence interface , where i is the sequence number of the layer interface.

7. The method for analyzing basin evolution using tilt coefficients based on seismic data according to any one of claims 1-3, 5, or 6, characterized in that, The measurement of the true length of each layer sequence interface includes: Each sequence interface is divided into j small regions using the finite element method, and each small region is an approximate straight line segment. Measure the vertical height of each small area. and horizontal length The Pythagorean theorem is used to calculate the true length of each small region. ; The true length of each sequence interface is obtained by summing the values ​​of each small region. .

8. The method for calculating tilt coefficients and analyzing basin evolution using seismic data according to claim 7, characterized in that, Step S4 includes: Calculate the tilting height difference based on the vertical height difference of each sequence interface. ; The tilt width difference is calculated based on the actual length of each layer interface. .

9. The method for calculating tilt coefficients and analyzing basin evolution using seismic data according to claim 8, characterized in that, The method for calculating the tilting coefficient based on the tilting height difference and tilting width difference of each sequence unit is as follows: 。 10. The method for calculating tilt coefficients and analyzing basin evolution using seismic data according to claim 9, characterized in that, The changes in the tilt coefficient characterize the basin evolution process, including: The rate of increase in the lateral area of ​​the basin is slow; The rate of increase in the lateral area of ​​the basin is moderate; : The rate of increase of the horizontal area of ​​the basin.

Images