Method for obtaining three-dimensional body by gridding two-dimensional seismic reflection data

Abstract

The invention provides a method for obtaining a three-dimensional body through two-dimensional seismic reflection data gridding, and belongs to the field of seismic data processing. Through a technical means of constructing a virtual grid through rotation, a two-dimensional measuring line is converted into a three-dimensional data body which is uniformly distributed in space, and subsequent data processing is not limited to one direction any more. Specifically, latitude and longitude coordinates of each discrete reflection data are obtained and converted into UTM projection rectangular coordinate values, and coordinate values of a longitude minimum point are determined; calculating the optimal azimuth angle of the grid according to the plane distribution characteristics of the discrete points, and determining the grid spacing along the azimuth angle direction and the vertical azimuth angle direction; the grid is rotated to the three-dimensional grid direction, the coordinates of the point with the minimum longitude value after rotation are extended outwards by a half grid interval, and the coordinates of the point serve as base points of the grid; all the coordinate points are rotated in the same way, data falling into the same grid are superposed, then the coordinate number of each point in the grid is calculated, and a three-dimensional data volume is obtained accordingly.

Description

TECHNICAL FIELD

[0001] The application provides an implementation method for obtaining a three-dimensional data body based on dense two-dimensional seismic reflection data with uneven spatial distribution through fast gridding, and belongs to the field of seismic data processing. BACKGROUND

[0002] Two-dimensional seismic data are usually collected along a single line or a series of parallel lines, which may lead to inaccurate interpretation of geological features and underground structure depth. In contrast, three-dimensional seismic data have better vertical resolution, more accurate migration, and can more conveniently and intuitively display horizons, interpret faults, analyze coherence volumes, describe reservoirs and the like, and are easy to comprehensively analyze geological structures. However, at the initial stage of exploration, for a work area with complex terrain and sea conditions, three-dimensional seismic exploration cannot be carried out due to exploration risks and cost considerations, and two-dimensional seismic exploration cannot meet the regularization requirements. Therefore, in order to improve the exploration accuracy, it is necessary to use two-dimensional seismic data with uneven spatial distribution to improve the reliability of evaluation of exploration areas and evaluation and optimization of reservoirs such as oil and gas and hydrates. One effective method is virtual three-dimensional seismic technology.

[0003] The existing virtual three-dimensional seismic technology converts two-dimensional lines into corresponding three-dimensional seismic data according to the arrangement mode of a three-dimensional observation system, and combines two-dimensional databases to establish a virtual three-dimensional database, so that three-dimensional data processing and interpretation technologies can be applied. In actual seismic exploration, for a certain special geological target, such as seabed heat flow, shallow gas and fault development, bedrock surface depth and the like, a small trace interval is received or a seabed ARV is collected, the line is sparse but the sampling is dense, the spatial distribution is uneven, and the line length, azimuth and coverage times vary irregularly. The commonly used virtual three-dimensional seismic method is usually realized by using Jason and the like, which has certain limitations.

[0004] At present, a three-dimensional gridding scheme for seismic data with strong universality, high efficiency and easy implementation is urgently needed to improve the imaging effect and interpretability of seismic data. In view of this, the application is proposed. SUMMARY

[0005] The method for obtaining a three-dimensional body by gridding two-dimensional seismic reflection data proposed in the application solves the problems existing in the prior art by rotating to construct a virtual grid, so as to realize a calculation process not affected by the azimuth and significantly simplify the calculation process of determining the relationship between scattered points and grid points, thereby converting two-dimensional lines into three-dimensional data bodies with uniform spatial distribution and making subsequent data processing no longer limited to one direction, so as to ensure that the results are more in line with geological rules and more convenient for geological interpretation.

[0006] Therefore, the method for obtaining a three-dimensional volume from two-dimensional seismic reflection data by gridding as described in this application involves obtaining the latitude and longitude coordinates of each discrete reflection data and converting them into UTM projected rectangular coordinates to determine the coordinates of the point with the minimum longitude; calculating the optimal azimuth angle of the grid based on the planar distribution characteristics of the discrete points, and determining the grid spacing along the azimuth direction and perpendicular to the azimuth direction; rotating the grid to the three-dimensional grid direction, and extending the coordinates of the point with the minimum longitude value outward by half a grid spacing, using the coordinates of this point as the base point of the grid; performing the same rotation on all coordinate points, superimposing the data falling within the same grid, and then calculating the coordinate number of each point in the grid to obtain the three-dimensional data volume.

[0007] The implementation steps include the following: Step (1): Determine the projection zone and the longitude of the central meridian based on the latitude and longitude coordinates of the reflection points within the work area; Step (2): Calculate the UTM projection coordinates of the reflection points of each two-dimensional survey line using coordinate projection; Step (3): Calculate and determine the azimuth angle of each two-dimensional survey line based on the UTM projection coordinates; the average azimuth angle of all two-dimensional survey lines that is less than or equal to the median of the azimuth variance is taken as the azimuth angle of the two-dimensional grid. Step (4): Calculate the azimuth angle of the two-dimensional grid; First, calculate the average value of the original azimuth angle for each survey line. : (1) Then, calculate the variance of the azimuth angle. : (2) Step (5): Rotate the survey line from the azimuth of the two-dimensional grid to the azimuth of the three-dimensional grid using coordinate rotation; Step (6): Determine the parameters of the three-dimensional data volume observation system; UTM projection coordinates of all reflection points Perform a coordinate rotation, the rotation angle being the azimuth angle of the 3D mesh. To obtain the rotated coordinates : (3) (4) in,( , ) is the minimum longitude coordinate ( , The projected coordinates after projection transformation. and These represent the desired 3D grid spacing for the output; Step (7): Data overlay within the same 3D grid; Step (8): Calculate the 3D mesh number of all reflection points; Based on the relationship between the coordinates of the reflection points after superposition and the coordinates of the mesh origin, calculate the coordinate number of each reflection point in the 3D mesh. : (5) (6) Step (9): Sort the coordinates of all reflection points after superposition according to the grid number to obtain a three-dimensional meshed three-dimensional data volume.

[0008] In step (1), input two-dimensional seismic reflection data located in the work area. The data includes track heads, survey line spacing and track spacing. The track heads contain spatial coordinate information of the reflection points. Obtain the latitude and longitude coordinates of all two-dimensional survey lines. ( Determine the minimum longitude coordinates. Add 180 to this value, divide by 6, round down, and add 1 to obtain the longitude of the central meridian in the coordinate projection. : (7) Step (2) involves converting the latitude and longitude coordinates of all reflection points into UTM projection coordinates. ( If the latitude value of the UTM projection coordinates is less than zero, then the work area is located in the Southern Hemisphere, and its latitude value calculation result needs to be increased by 10,000,000; otherwise, the work area is located in the Northern Hemisphere.

[0009] Step (3) includes fitting the original azimuth angle of each two-dimensional survey line using the least squares principle, calculating the variance of the azimuth angle and sorting them from smallest to largest, determining the median of the azimuth angle variance, and selecting the average value of the azimuth angles with variances less than or equal to the median as the azimuth angle of the two-dimensional grid to avoid interference from data with large azimuth angle offsets; and based on the UTM projection coordinate values... The original azimuth angle of each two-dimensional survey line is fitted using the least squares principle. The azimuth angle calculation process is as follows: Step (3.1): Calculate all and and and ; Step (3.2): Calculate all and and and ; Step (3.3): Calculate the slope of the line. : (8) Step (3.4): Calculate the azimuth angle ( ): (9) Step (5) includes sorting the azimuth variances of each survey line from smallest to largest, and selecting the average azimuth variance of the top 50% as the azimuth of the three-dimensional grid. When the survey line is oriented northwest to southeast. Take the positive value, when the direction is southwest to northeast. Take the negative value; Step (7) includes calculating the origin of the three-dimensional mesh and determining the desired output three-dimensional mesh interval. and The minimum longitude coordinates ( , Projected coordinates after projection transformation , Expand outward by half and The origin of the three-dimensional mesh is taken as the first one. ; Among them, when When the value is positive, the origin of the 3D mesh is taken as... Conversely, the origin of the 3D mesh is taken as... ; The data falling into each 3D grid is checked. If there are multiple data in a grid, these data are superimposed. The superimposed result is used as the data of the grid center point. The coordinates of the superimposed result are taken as the coordinates of the grid center point. Assume the first Within each grid The data point, the first The distance between each data point and the center point of the grid is... Then the data within this grid is: (10) The parameters of the three-dimensional data volume observation system in step (9) include the coordinates of the corner points of the work area, the spacing between the main survey lines, the spacing between the connecting survey lines, and the track spacing.

[0010] This application proposes an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: when the processor executes the program, it implements the above-mentioned method for obtaining a three-dimensional volume by meshing two-dimensional seismic reflection data.

[0011] This application proposes a computer-readable storage medium storing a computer program, characterized in that: when the computer program is executed, it can realize the above-mentioned method for obtaining a three-dimensional volume by meshing two-dimensional seismic reflection data.

[0012] In summary, this application has the following advantages and beneficial effects compared with the prior art: 1. This application constructs a virtual three-dimensional mesh through azimuth angle calculation and coordinate rotation, which can effectively rotate a spatially uneven two-dimensional observation system to any azimuth angle. The calculation process is not affected by the original azimuth angle, which greatly simplifies the calculation of the relationship between scattered points and grid points, and the calculation results are more accurate.

[0013] 2. After converting the two-dimensional survey lines into a spatially uniformly distributed three-dimensional data volume, the subsequent data processing is no longer limited to one direction, ensuring that the results are more consistent with geological laws and more convenient for geological interpretation.

[0014] 3. This application only requires calculation of spatial coordinates, which is more efficient and more suitable for densely sampled seismic data and dense discrete point data related to geodesy (such as gravity and magnetism). Attached Figure Description

[0015] The implementation process of the present application will now be further explained and illustrated with reference to the following figures.

[0016] Figure 1 This is a flowchart of the method for obtaining a three-dimensional volume from two-dimensional seismic reflection data by meshing, as described in this application. Figure 2 A schematic diagram showing the location of the common center point of dense two-dimensional seismic reflection data with uneven spatial distribution; Figure 2 The middle arrow points to the direction of the azimuth of the survey line in the work area; Figure 3 A schematic diagram for calculating the azimuth of a portion of the survey line; Figure 3 Solid lines represent two-dimensional survey lines, and dashed arrows indicate the azimuth direction of the corresponding survey line; Figure 4 This is a schematic diagram of the rotation of the azimuth angle of the survey line; Figure 4 middle This is the difference between the azimuth angle of the 3D mesh and the azimuth angle of the 2D mesh, i.e., the rotation azimuth angle; Figure 5 A schematic diagram illustrating the effect of interactive orientation determination for 3D surface meshes; Figure 6 This is a two-dimensional survey profile of a certain work area; Figure 7 for Figure 6 The corresponding survey line profile in the 3D data volume after meshing; Detailed Implementation

[0017] To better understand the above-mentioned objectives, features, and advantages of this application, the application will be further described below in conjunction with the accompanying drawings and embodiments. Many specific details are set forth in the following description to provide a thorough understanding of this application; however, this application may be implemented in other ways than those described herein, and therefore, this application is not limited to the specific embodiments disclosed below.

[0018] Example 1, such as Figures 1 to 7 As shown, this application proposes a method for obtaining a three-dimensional volume from two-dimensional seismic reflection data by gridding. The method involves acquiring the latitude and longitude coordinates of each discrete reflection data point and converting them into UTM projected rectangular coordinates, determining the coordinates of the point with the minimum longitude; calculating the optimal azimuth angle of the grid based on the planar distribution characteristics of the discrete points, and determining the grid spacing along the azimuth direction and perpendicular to the azimuth direction; rotating the grid to the three-dimensional grid direction, and extending the coordinates of the point with the minimum longitude value outwards by half a grid spacing, using the coordinates of this point as the base point of the grid; performing the same rotation on all coordinate points, superimposing the data falling within the same grid, and then calculating the coordinate number of each point in the grid to obtain the three-dimensional data volume.

[0019] The method includes the following implementation steps: Step (1): Determine the projection zone and the longitude of the central meridian based on the latitude and longitude coordinates of the reflection points within the work area; Input two-dimensional seismic reflection data located within the work area. The data includes track heads, survey line spacing, and track spacing. Track heads contain spatial coordinate information of reflection points. Obtain the latitude and longitude coordinates of all two-dimensional survey lines. ( Determine the minimum longitude coordinates. Add 180 to this value, divide by 6, round down, and add 1 to obtain the longitude of the central meridian in the coordinate projection. : (1) Step (2): Calculate the UTM projection coordinates of the reflection points of each two-dimensional survey line using coordinate projection; Convert the latitude and longitude coordinates of all reflection points to UTM projected coordinates ( ); If the latitude value of the UTM projection coordinates is less than zero, then the work area is located in the Southern Hemisphere, and its latitude value calculation result needs to be increased by 10,000,000; otherwise, the work area is located in the Northern Hemisphere. Step (3): Calculate and determine the azimuth angle of each two-dimensional survey line based on the UTM projection coordinates; The average azimuth of all two-dimensional survey lines that is less than or equal to the median of the azimuth variance is taken as the azimuth of the two-dimensional grid. Specifically, the original azimuth angle of each two-dimensional survey line is fitted using the least squares principle, the variance of the azimuth angle is calculated and sorted from smallest to largest, the median of the azimuth angle variance is determined, and the average value of the azimuth angles with variance less than or equal to the median is selected as the azimuth angle of the two-dimensional grid to avoid interference from data with large azimuth angle offsets. Based on UTM projection coordinates The original azimuth angle of each two-dimensional survey line is fitted using the least squares principle. The azimuth angle calculation process is as follows: Step (3.1): Calculate all and and and ; Step (3.2): Calculate all and and and ; Step (3.3): Calculate the slope of the line. : (2) Step (3.4): Calculate the azimuth angle ( ): (3) Step (4): Calculate the azimuth angle of the two-dimensional grid; First, calculate the average value of the original azimuth angle for each survey line. : (4) Then, calculate the variance of the azimuth angle. : (5) Step (5): Rotate the survey line from the azimuth of the two-dimensional grid to the azimuth of the three-dimensional grid using coordinate rotation; Sort the azimuth variances of each survey line from smallest to largest, and select the average azimuth variance of the top 50% as the azimuth of the 3D mesh. ; To avoid interference from data with large azimuth offsets, when the survey line azimuth is NW-SEM... Take the positive value, when the direction is southwest to northeast. Take the negative value; Step (6): Determine the parameters of the three-dimensional data volume observation system; UTM projection coordinates of all reflection points Perform a coordinate rotation, the rotation angle being the azimuth angle of the 3D mesh. To obtain the rotated coordinates : (6) (7) in,( , ) is the minimum longitude coordinate ( , The projected coordinates after projection transformation. and These represent the desired 3D grid spacing for the output; Step (7): Data overlay within the same 3D grid; Calculate the origin of the 3D mesh, based on the desired output 3D mesh spacing. and The minimum longitude coordinates ( , Projected coordinates after projection transformation , Expand outward by half and The origin of the three-dimensional mesh is taken as the first one. ; Among them, when When the value is positive, the origin of the 3D mesh is taken as... Conversely, the origin of the 3D mesh is taken as... ; The data falling into each 3D grid is checked. If there are multiple data in a grid, these data are superimposed. The superimposed result is used as the data of the grid center point. The coordinates of the superimposed result are taken as the coordinates of the grid center point. Assume the first Within each grid The data point, the first The distance between each data point and the center point of the grid is... Then the data within this grid is: (8) Step (8): Calculate the 3D mesh number of all reflection points; Based on the relationship between the coordinates of the reflection points after superposition and the coordinates of the mesh origin, calculate the coordinate number of each reflection point in the 3D mesh. : (9) (10) Step (9): Sort the coordinates of all reflection points after superposition according to the grid number to obtain a three-dimensional meshed three-dimensional data volume; The parameters of the three-dimensional data volume observation system include the coordinates of the corner points of the work area, the spacing between the main survey lines, the spacing between the connecting survey lines, and the track spacing.

[0020] like Figure 7 As shown, Figure 7 for Figure 6 In the 3D data volume after rapid gridding of medium- and two-dimensional seismic reflection data, the corresponding survey line profile in the figure shows an improved signal-to-noise ratio, especially in the area circled by the ellipse, where the signal-to-noise ratio is significantly improved, and weak reflection phase axes are imaged more clearly.

[0021] This application also proposes a novel electronic device, which includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the program, it implements the above-mentioned method for obtaining a three-dimensional volume by meshing two-dimensional seismic reflection data.

[0022] This application also proposes a novel computer-readable storage medium storing a computer program that, when executed, enables the above-described method for obtaining a three-dimensional volume from two-dimensional seismic reflection data through gridding.

[0023] As described above, similar technical solutions can be derived from the solutions presented in the accompanying drawings and description, and all of them still fall within the scope of the claims of this application.

Claims

1. A method of gridding two-dimensional seismic reflection data to obtain a three-dimensional volume, characterized by: The latitude and longitude coordinates of each discrete reflection data are obtained and converted into UTM projection rectangular coordinate values, and the coordinate value of the minimum longitude point is determined; the best azimuth angle of the grid is calculated according to the plane distribution characteristics of the discrete points, and the grid spacing along the azimuth angle direction and the vertical azimuth angle direction is determined; the grid is rotated to the three-dimensional grid direction, and the coordinate of the minimum longitude value point after rotation is extended outward by half the grid spacing, and the coordinate of the point is taken as the base point of the grid; all coordinate points are rotated in the same way, the data falling into the same grid are superimposed, and then the coordinate number of each point in the grid is calculated, and the three-dimensional data body is obtained accordingly.

2. The method for obtaining a three-dimensional body by griding two-dimensional seismic reflection data according to claim 1, characterized in that it comprises the following implementation steps: Step (1), determining the projection zone and the central meridian longitude according to the latitude and longitude coordinates of the reflection points in the work area; Step (2), calculating the UTM projection coordinate values of the reflection points of each two-dimensional survey line through coordinate projection; Step (3), determining the azimuth angle of each two-dimensional survey line based on the UTM projection coordinates; the average value of the azimuth angles less than or equal to the median of the azimuth angle variance is taken as the two-dimensional grid azimuth angle; Step (4), calculating the azimuth angle of the two-dimensional grid; Step (5), rotating the survey line from the two-dimensional grid azimuth angle to the three-dimensional grid azimuth angle by coordinate rotation; First, the average value of the original azimuth of each line is calculated : (4) Then, the variance of the azimuth angle is calculated : (5) Step (6), determining the observation system parameters of the three-dimensional data body; Step (7), superimposing the data in the same three-dimensional grid; UTM projection coordinate values of all reflection points Coordinate rotation is performed with a rotation angle of the azimuth angle of the three-dimensional grid , to obtain the rotated coordinates : (6) (7) wherein, , ) is the projection coordinate after the projection conversion of the minimum longitude coordinate ( , ), and are the three-dimensional grid intervals of the desired output, respectively. Step (8), calculating the three-dimensional grid number of all reflection points; Step (9), sorting the coordinates of all superimposed reflection points according to the grid number to obtain the three-dimensional data body of the three-dimensional grid. According to the relationship between the coordinates of the superimposed reflection points and the coordinates of the grid origin, the coordinate number of each reflection point in the three-dimensional grid is calculated : (9) (10) 3. The method for obtaining a three-dimensional body by griding two-dimensional seismic reflection data according to claim 2, characterized in that: In step (1), the two-dimensional seismic reflection data in the work area are input, and the data includes the trace header, the survey line spacing and the trace spacing, and the trace header contains the spatial coordinate information of the reflection points.

4. The method for obtaining a three-dimensional body by griding two-dimensional seismic reflection data according to claim 2, characterized in that: Obtain the latitude and longitude coordinates of all 2D lines ( ), determine the minimum longitude coordinate , add 180 to this value, divide by 6, take the integer part, and add 1 to obtain the central meridian longitude of the coordinate projection : (1) 。 If the latitude value of the UTM projection coordinate is less than zero, the work area is in the southern hemisphere, and the latitude value calculation result needs to be added by 10000000; otherwise, the work area is in the northern hemisphere. The step (2) converts the longitude and latitude coordinates of all the reflection points into UTM projection coordinates ( ) 5. The method for obtaining a three-dimensional body by griding two-dimensional seismic reflection data according to claim 2, characterized in that: In step (3), the original azimuth angle of each two-dimensional survey line is fitted by using the least square principle, the variance of the azimuth angle is calculated and sorted from small to large, the median of the azimuth angle variance is determined, and the average value of the azimuth angle less than or equal to the median is selected as the azimuth angle of the two-dimensional grid to avoid the interference of the data with large azimuth angle deviation; 6. The method for obtaining a three-dimensional body by griding two-dimensional seismic reflection data according to claim 2, characterized in that: According to the UTM projection coordinate values The original azimuth of each two-dimensional survey line is fitted by using the least square principle, and the azimuth calculation process is as follows: Step (3.1), calculating the sum of all and and and ; Step (3.2), calculating the sum of all and and and ; Step (3.3), calculating the straight line slope : (2) Step (3.4), calculating the azimuth angle :​ (3) 。 The data falling into each three-dimensional grid is checked, if there are multiple data in a grid, the data are superimposed, the superimposed result is taken as the data of the grid center point, and the coordinate of the superimposed result is taken as the grid center point coordinate. The step (5) comprises: sorting the azimuth angle variance of each survey line from small to large, and selecting the average value of the azimuth angle corresponding to the first 50% as the azimuth angle of the three-dimensional grid ; When the line orientation is northwest-southeast Take the positive value, southwest-northeast direction Take the negative value.

7. The method of obtaining a three-dimensional volume from a two-dimensional seismic reflection data grid of claim 2, wherein: The step (7) includes calculating a three-dimensional grid origin, and projecting the minimum longitude coordinate (x0, y0) to the projected coordinate (x0', y0') after the projection conversion, and extending the projected coordinate (x0', y0') outward by half of the three-dimensional grid interval and to serve as the origin of the three-dimensional grid , , and ;​​​ wherein, when the three-dimensional grid origin is taken as ; otherwise, the three-dimensional grid origin is taken as ; ​ Assume that there are data points in the first grid, and the value of the data point is , then the value of the data in the grid is: ​ (8) 。 8. The method of obtaining a three-dimensional volume from a two-dimensional seismic reflection data grid of claim 2, wherein: The step (9) is to observe the system parameters of the three-dimensional data body, including the coordinates of the corner points of the work area, the interval of the main survey line, the interval of the connecting survey line and the trace interval.

9. An electronic device comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, characterized in that: The processor implements the method for obtaining a three-dimensional body by gridding two-dimensional seismic reflection data when executing the program.

10. A computer readable storage medium storing a computer program, characterized in that: The method for obtaining a three-dimensional body by gridding two-dimensional seismic reflection data can be implemented when the computer program is executed.

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