Rapid construction method for total fall-distance curve of complex fault zone

Abstract

The invention relates to the technical field of seismic data processing methods, in particular to a rapid construction method for a total fall-distance curve of a complex fault zone, which comprises the following steps: S1, rotating the complex fault zone in the east-west direction, S2, establishing a plurality of equidistant vertical lines covering the length and width of the complex fault zone according to the length and width range of the complex fault zone, a plurality of vertical lines intersect with the fracture structure line to produce a plurality of intersection points, and the abscissa and the ordinate of each intersection point and the fall corresponding to the abscissa and the ordinate are solved; s3, grouping and summing the fall of the intersection points on the same vertical line to obtain the total fall of each vertical line of the complex fault zone, and then connecting the abscissa of each vertical line intersection point and the total fall as coordinate points to form a total fall curve, the overall complex fault zone total fall curve is translated leftwards to the original point of the rectangular coordinate system to construct the complex fault zone total fall-distance curve, the operability is high and fast, and the complex fault zone total fall-distance curve can be effectively constructed.

Description

Technical Field

[0001] The invention relates to the technical field of seismic data processing methods, and in particular to a method for quickly constructing a total drop-distance curve of a complex fault zone. Background Art

[0002] At present, the construction of fault drop-distance curves is mainly completed in the following ways: (1) using existing structural maps or three-dimensional seismic data to interpret the distribution of faults; (2) manually calculating the fault drop on fixed-interval seismic profiles and the distance between the profile and the left end point of the fault, and connecting the distance and drop arrays into a curve to form a fault drop-distance curve.

[0003] When dealing with complex fault zones with a large number of faults, variable orientations, complex positional relationships, and a wide extension range, there are the following disadvantages:

[0004] (1) The existing technology manually generates the drop-distance curve of each fault by statistical analysis. All the obtained curves start from the rectangular coordinate origin (0,0), which makes it impossible to obtain the total drop of the same position point in the complex fault zone, and cannot reflect the lateral change of the total drop of the complex fault zone along the distance.

[0005] (2) For the case of large differences in fault lengths within a complex fault zone, using a fixed large spacing for drop statistics is suitable for longer extended faults, but it may lead to incomplete statistical information for shorter extended faults. However, using a fixed smaller spacing statistical method will greatly increase the workload; using a profile statistical method with different spacing for faults with different extension lengths and different distributions will result in inconsistent intervals of distance values, which is not conducive to the rapid calculation of the total drop.

[0006] (3) In complex fault zones, due to the inconsistency of fault strike, the statistical method of seismic profiles with fixed orientation and spacing cannot accurately reflect the actual drop of each fault. Summary of the invention

[0007] The present invention aims to provide a method for quickly constructing a total drop-distance curve of a complex fault zone to solve the problems raised in the background technology.

[0008] In order to achieve the above object, the basic scheme of the present invention is as follows: a method for quickly constructing a total drop-distance curve of a complex fault zone, comprising the following steps:

[0009] S1: Use the depth domain 3D seismic data to make a seismic stratigraphic map, determine the plane range and fault structure line of the complex fault zone according to the seismic stratigraphic map, measure the direction of all fault structure lines in the complex fault zone, and calculate the arithmetic mean of the direction in θ iis the azimuth of the i-th fault, the arithmetic mean of the strike represents the value of the average strike line of the complex fault zone, the complex fault zone is rotated so that the average strike line of the complex fault zone becomes east-west, the horizontal coordinate X1 and the vertical coordinate Y1 that can represent the plane position of the fault structure line after rotation are recorded, and the fault structure line drop Z1 is generated according to the contour map around the rotated complex fault zone, so that the fault structure line contains three columns of data: the horizontal coordinate X1, the vertical coordinate Y1 and the drop Z1;

[0010] S2: along the rectangular coordinate system, the length range and width range of the rotated complex fault zone are measured respectively, and a number of equally spaced vertical lines covering the length and width of the complex fault zone are established according to the length range and width range of the complex fault zone, wherein the spacing between the vertical lines is equal to the spacing between seismic traces, and the vertical lines intersect with the fault structural line to produce a number of intersection points, and the abscissa X2 and the ordinate Y2 of each intersection point and the corresponding drop Z2 are calculated respectively;

[0011] S3: Group and sum the drop Z2 of the intersection points on the same vertical line to obtain the total drop C at each vertical line of the complex fault zone, then connect the horizontal coordinate X2 of each vertical line intersection point and the total drop C as coordinate points to form a total drop curve, perform maximum percentile filtering on the total drop curve, remove abnormal points in the curve, draw the total drop curve of the complex fault zone, and finally translate the total drop curve of the complex fault zone to the left as a whole to the origin of the rectangular coordinate system to construct the total drop-distance curve of the complex fault zone.

[0012] Furthermore, step S2-2 is also included between step S2 and step S3: projecting the intersection points for observation to ensure that the intersections of the vertical line and the fracture structural line have corresponding intersection points.

[0013] The beneficial effects of this scheme are as follows: (1) By uniformly rotating the average strike line of the complex fault zone, the relative position relationship of the internal faults in the complex fault zone is retained. The drop values ​​of the internal faults are extracted through the seismic stratigraphic structure map while the relative positions remain unchanged, thus obtaining a spatially reliable data source for constructing the total drop-distance curve of the complex fault zone.

[0014] (2) The drop obtained from the seismic stratigraphic map is completely retained on the fault structure line. By measuring the length and width of the complex fault zone, dense vertical lines with the spacing between seismic traces as the spacing value are established, and the drop values ​​of different fault lines on the vertical lines are collected. This unifies the sampling method of different fault drops within the complex fault zone, making a consistent method for constructing the total drop curve of the complex fault zone.

[0015] (3) This scheme extracts the fault drop on the structural map by rotating the average strike of the complex fault zone to the east-west direction. It does not rely on the statistics of the drop values ​​of the fixed-interval seismic profiles one by one. It converts the determination of the total drop of the complex fault zone into a geometric analysis and digital signal analysis problem between the dense vertical lines and the fault structural lines. This makes the construction process of the total drop of the complex fault zone more visual and concrete, with strong operability and speed, and can effectively construct the total drop-distance curve of the complex fault zone. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of a flow chart of an embodiment of the present invention;

[0017] Figure 2 is a seismic stratigraphic structure diagram in an embodiment of the present invention;

[0018] Figure 3 A structural diagram of a complex fault zone in an embodiment of the present invention;

[0019] Figure 4 This is a structural diagram of a complex fracture zone after rotation in an embodiment of the present invention;

[0020] Figure 5 It is a fall diagram of the fracture structure line of the complex fracture zone after rotation in the embodiment of the present invention;

[0021] Figure 6 is a schematic diagram of a fracture structural line and a plurality of vertical lines in an embodiment of the present invention;

[0022] Figure 7 It is a partial schematic diagram of the intersection of the fracture construction line and a plurality of vertical lines in an embodiment of the present invention;

[0023] Figure 8 It is the total drop curve of the complex fault zone before filtering in the embodiment of the present invention;

[0024] Fig. 9 It is a filtered curve of the total drop of the complex fault zone in the embodiment of the present invention;

[0025] Fig.10 It is the total drop-distance curve of the complex fault zone in the embodiment of the present invention. DETAILED DESCRIPTION

[0026] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] Example

[0028] Basically as attached Figure 1 As shown: A method for quickly constructing a total drop-distance curve of a complex fault zone, including the following steps:

[0029] S1: Combination Figure 2 As shown in the figure, the seismic stratigraphic map is produced by using the three-dimensional seismic data in the depth domain. Figure 3 As shown, according to the seismic stratigraphic structure map, the plane range and fault structure line of the complex fault zone are determined, the direction of all fault structure lines in the complex fault zone is measured, and the arithmetic mean of the direction is calculated. in θ i is the azimuth of the i-th fault, and the arithmetic mean of the strike direction represents the value of the average strike line of the complex fault zone. Figure 4 As shown, the complex fault zone is rotated so that the average strike line of the complex fault zone becomes east-west. Figure 5 As shown, the horizontal coordinate X1 and the vertical coordinate Y1 that can represent the plane position of the fault structure line after rotation are recorded, and the fault structure line drop Z1 is generated according to the contour map around the complex fault zone after rotation, so that the fault structure line contains three columns of data: the horizontal coordinate X1, the vertical coordinate Y1 and the drop Z1;

[0030] S2: Combination Figure 6 As shown, the length range and width range of the rotated complex fault zone are measured along the rectangular coordinate system, and a number of equally spaced vertical lines covering the length and width of the complex fault zone are established according to the length range and width range of the complex fault zone. The spacing between the vertical lines is equal to the spacing between seismic traces. Figure 7 As shown, a number of the vertical lines intersect with the fault structural line to produce a number of intersection points, and the horizontal coordinate X2 and the vertical coordinate Y2 of each intersection point and the corresponding drop Z2 are respectively calculated;

[0031] S3: Project the intersection points to ensure that the intersections of the vertical lines and the fault structural lines have corresponding intersection points. Group the drop Z2 of the intersection points on the same vertical line and sum them up to obtain the total drop C of each vertical line in the complex fault zone. Then, connect the horizontal coordinate X2 of each vertical line intersection point and the total drop C as coordinate points to form a total drop curve (such as Figure 8 The total drop curve is filtered by the maximum percentile, and the abnormal points in the curve are removed to draw the total drop curve of the complex fault zone (as shown in Fig. 9 Finally, the total drop curve of the complex fault zone is shifted to the left to the origin of the rectangular coordinate system to construct the total drop-distance curve of the complex fault zone (as shown in Fig.10 shown).

[0032] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0033] The above is only an embodiment of the present invention. The common sense such as the known specific structure and characteristics in the scheme is not described in detail here. The ordinary technicians in the relevant field know all the common technical knowledge in the technical field of the invention before the application date or priority date, can obtain all the existing technologies in the field, and have the ability to apply the conventional experimental means before that date. The ordinary technicians in the relevant field can improve and implement this scheme in combination with their own abilities under the enlightenment given by this application. Some typical known structures or known methods should not become obstacles for ordinary technicians in the relevant field to implement this application. It should be pointed out that for those skilled in the art, without departing from the structure of the present invention, several deformations and improvements can be made, which should also be regarded as the protection scope of the present invention, which will not affect the effect of the implementation of the present invention and the practicality of the patent. The protection scope required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to interpret the content of the claims.

Claims

1. A method for quickly constructing a total drop-distance curve of a complex fault zone, characterized by: The following steps are involved: S1: Use the depth domain 3D seismic data to make a seismic stratigraphic map, determine the plane range and fault structure line of the complex fault zone according to the seismic stratigraphic map, measure the direction of all fault structure lines in the complex fault zone, and calculate the arithmetic mean of the direction in θ i is the azimuth of the i-th fault, the arithmetic mean of the strike represents the value of the average strike line of the complex fault zone, the complex fault zone is rotated so that the average strike line of the complex fault zone becomes east-west, the horizontal coordinate X1 and the vertical coordinate Y1 that can represent the plane position of the fault structure line after rotation are recorded, and the fault structure line drop Z1 is generated according to the contour map around the rotated complex fault zone, so that the fault structure line contains three columns of data: the horizontal coordinate X1, the vertical coordinate Y1 and the drop Z1; S2: along the rectangular coordinate system, the length range and width range of the rotated complex fault zone are measured respectively, and a number of equally spaced vertical lines covering the length and width of the complex fault zone are established according to the length range and width range of the complex fault zone, wherein the spacing between the vertical lines is equal to the spacing between seismic traces, and the vertical lines intersect with the fault structural line to produce a number of intersection points, and the abscissa X2 and the ordinate Y2 of each intersection point and the corresponding drop Z2 are calculated respectively; S3: Group and sum the drop Z2 of the intersection points on the same vertical line to obtain the total drop C at each vertical line of the complex fault zone, then connect the horizontal coordinate X2 of each vertical line intersection point and the total drop C as coordinate points to form a total drop curve, perform maximum percentile filtering on the total drop curve, remove abnormal points in the curve, draw the total drop curve of the complex fault zone, and finally translate the total drop curve of the complex fault zone to the left as a whole to the origin of the rectangular coordinate system to construct the total drop-distance curve of the complex fault zone.

2. The method for quickly constructing a total drop-distance curve of a complex fault zone according to claim 1, characterized in that: The step S2-2 is also included between step S2 and step S3: projecting the intersection points for observation to ensure that the intersections of the vertical line and the fracture structural line have corresponding intersection points.

Images