阅读说明：本技术 消除速度模型突变界面的方法、叠前深度偏移处理方法 (Method for eliminating abrupt interface of velocity model and prestack depth migration processing method ) 是由 梁硕博 刘小民 裴云龙 隋俊杰 任艺 于 2019-08-21 设计创作，主要内容包括：本发明公开了一种消除速度模型突变界面的方法、叠前深度偏移处理方法及存储介质,所述消除速度模型突变界面的方法包括：在深度域层速度模型的突变界面周围预设的缓冲距离内创建缓冲区域；按照预设方向构建从缓冲区域的第一边界至第二边界的多条平滑路径；根据每一条平滑路径两端样点的速度值以及预设速度梯度初始值确定每一条平滑路径上各样点的速度平滑值；将每一条平滑路径上各样点的速度平滑值作为各样点的速度值,使得同一条平滑路径上的各样点的速度值依次递增或递减,以消除深度域层速度模型的突变界面。本发明消除了深度域层速度模型的突变界面从而消除成像假象甚至假断层,提高了深度域层速度模型精度。(The invention discloses a method for eliminating a speed model abrupt interface, a prestack depth migration processing method and a storage medium, wherein the method for eliminating the speed model abrupt interface comprises the following steps: creating a buffer area within a preset buffer distance around an abrupt interface of the depth domain layer speed model; constructing a plurality of smooth paths from a first boundary to a second boundary of the buffer area according to a preset direction; determining the speed smooth value of each sampling point on each smooth path according to the speed values of the sampling points at the two ends of each smooth path and a preset speed gradient initial value; and taking the speed smooth value of each sampling point on each smooth path as the speed value of each sampling point, and enabling the speed value of each sampling point on the same smooth path to be sequentially increased or decreased so as to eliminate the abrupt interface of the depth domain layer speed model. The invention eliminates the abrupt interface of the depth domain layer velocity model, thereby eliminating imaging false image and even false fault and improving the precision of the depth domain layer velocity model.)

1. A method of eliminating abrupt interfaces of velocity models, comprising the steps of:

s100, creating a buffer area within a preset buffer distance around a sudden change interface of the depth domain layer velocity model;

s200, constructing a plurality of smooth paths from a first boundary to a second boundary of the buffer area according to a preset direction;

s300, determining a speed smooth value of each sampling point on each smooth path according to the speed values of the sampling points at the two ends of each smooth path and a preset speed gradient initial value;

s400, taking the speed smooth value of each sampling point on each smooth path as the speed value of each sampling point, and enabling the speed value of each sampling point on the same smooth path to be sequentially increased or decreased, so as to eliminate the abrupt interface of the depth domain layer speed model.

2. The method according to claim 1, wherein step S100 comprises the following steps:

s110, forming a two-dimensional abrupt interface contour line according to an abrupt interface of the depth domain layer velocity model;

and S120, taking the two-dimensional abrupt interface contour line as a boundary, and taking a region formed by sampling points with the distance between two opposite sides of the boundary not exceeding a preset buffer distance as a buffer region.

3. The method according to claim 1, wherein in step S200, the preset direction is perpendicular to a depth direction of the depth domain layer velocity model.

4. The method according to claim 1, wherein step S300 specifically comprises the steps of:

s310, determining the number of segments of the smooth path and the speed value of each small segment of the smooth path according to the speed initial value, the speed end value and a preset speed gradient initial value by taking the speed value of the sampling point at the starting end of the smooth path as a speed initial value and the speed value of the sampling point at the ending end of the smooth path as a speed end value;

and S320, taking the speed value of the small section of the smooth path as the speed smooth value of each sampling point on the small section of the smooth path.

5. The method according to claim 4, wherein step S310 specifically comprises the steps of:

s311, determining the number of segments of the smooth path according to the speed initial value, the speed end value and a preset speed gradient initial value by taking the speed value of the sample point at the starting end of the smooth path as the speed initial value and taking the speed value of the sample point at the ending end of the smooth path as the speed end value;

s312, determining the speed value of each small section of the smooth path according to the speed initial value, the preset speed gradient initial value and the number of the sections of the smooth path.

6. The method according to claim 5, wherein in step S311, the number of segments of the smooth path is determined by the following expression according to the speed start value, the speed end value, and a preset speed gradient initial value:

where D is the number of segments of the smooth path, v₀Is a velocity start value, v_tδ v is a preset velocity gradient initial value for the velocity end value.

7. The method of claim 5, wherein in step S312, the speed value of each smooth path segment is determined according to the speed start value, the preset speed gradient initial value and the number of segments of the smooth path:

v_i＝v₀+iδv

wherein v is_iFor the velocity value of the current smooth path segment, v₀The speed initial value is delta v, the preset speed gradient initial value is delta v, and the number of sections of the current smooth path section calculated from the starting end of the smooth path is i.

8. The method of claim 1, further comprising, after step S400:

judging whether a sudden change interface of the depth domain layer velocity model is eliminated;

and when the abrupt interface of the depth domain layer speed model is not eliminated, correcting the preset initial value of the speed gradient, enabling the preset initial value of the speed gradient to be equal to the corrected value of the speed gradient, and returning to the step S300 to continuously correct the speed values of all sampling points on each smooth path.

9. A prestack depth migration processing method is characterized by comprising the following steps:

obtaining a depth domain layer velocity model of the eliminated abrupt interface according to the method for eliminating the abrupt interface of the velocity model of any one of claims 1 to 8;

and performing pre-stack depth migration processing on the seismic data by using the depth domain layer velocity model.

10. A storage medium, on which a computer program is stored, characterized in that the program, when being executed by a processor, carries out the steps of the method according to any one of claims 1 to 9.

Technical Field

The invention belongs to the technical field of geophysical exploration seismic data processing, and particularly relates to a method for eliminating a velocity model abrupt interface, a prestack depth migration processing method and a storage medium.

Background

At present, the seismic data processing usually needs prestack depth migration processing, and the key is to do prestack depth domain velocity modeling work.

In the prestack depth domain velocity modeling process, the mesh chromatography is usually adopted to update the velocity of the initial velocity model of the depth domain, namely, carrying out grid chromatography according to the fact whether the depth migration gather is leveled up or not to obtain the speed updating quantity, however, when the geological low speed or high speed of a certain region position exists in a work area, such as salt dome, gas cloud area and the like, the signal-to-noise ratio of the depth offset gather at the position is low, the region can not be updated by the grid chromatography, at the moment, the speed model of the corresponding region position is firstly directly and manually edited according to geological knowledge, and then the speed is updated by the grid chromatography, however, the position of the region after manual editing is easy to have a sudden interface with a great difference from the surrounding speed model, so that imaging artifacts and even false faults can occur, and wrong information is provided for the post-prestack depth migration processing.

In addition, in the process of prestack depth domain speed modeling, when multiple pieces of data are processed in a continuous mode to perform depth domain speed modeling, the initial speed models of the depth domains of the two work areas are directly spliced together, and abrupt interface phenomena can occur at the splicing position, so that imaging false images and even false fault phenomena can occur, and wrong information is provided for the prestack depth migration processing in the later period.

There is a need for a method for eliminating abrupt interfaces of velocity models, a method for processing prestack depth migration, and a storage medium.

Disclosure of Invention

The invention aims to solve the technical problem that when an abrupt interface appears in the existing prestack depth domain speed modeling process, imaging false images and even false fault phenomena appear, and wrong information is provided for the prestack depth migration processing in the later period.

In order to solve the technical problem, the invention provides a method for eliminating a sudden change interface of a speed model, which comprises the following steps:

s100, creating a buffer area within a preset buffer distance around a sudden change interface of the depth domain layer velocity model;

s200, constructing a plurality of smooth paths from a first boundary to a second boundary of the buffer area according to a preset direction;

s300, determining a speed smooth value of each sampling point on each smooth path according to the speed values of the sampling points at the two ends of each smooth path and a preset speed gradient initial value;

s400, taking the speed smooth value of each sampling point on each smooth path as the speed value of each sampling point, and enabling the speed value of each sampling point on the same smooth path to be sequentially increased or decreased, so as to eliminate the abrupt interface of the depth domain layer speed model.

Preferably, step S100 specifically includes the following steps:

s110, forming a two-dimensional abrupt interface contour line according to an abrupt interface of the depth domain layer velocity model;

and S120, taking the two-dimensional abrupt interface contour line as a boundary, and taking a region formed by sampling points with the distance between two opposite sides of the boundary not exceeding a preset buffer distance as a buffer region.

Preferably, in step S200, the preset direction is perpendicular to the depth direction of the depth domain layer velocity model.

Preferably, step S300 specifically includes the following steps:

s310, determining the number of segments of the smooth path and the speed value of each small segment of the smooth path according to the speed initial value, the speed end value and a preset speed gradient initial value by taking the speed value of the sampling point at the starting end of the smooth path as a speed initial value and the speed value of the sampling point at the ending end of the smooth path as a speed end value;

and S320, taking the speed value of the small section of the smooth path as the speed smooth value of each sampling point on the small section of the smooth path.

Preferably, step S310 specifically includes the following steps:

s311, determining the number of segments of the smooth path according to the speed initial value, the speed end value and a preset speed gradient initial value by taking the speed value of the sample point at the starting end of the smooth path as the speed initial value and taking the speed value of the sample point at the ending end of the smooth path as the speed end value;

s312, determining the speed value of each small section of the smooth path according to the speed initial value, the preset speed gradient initial value and the number of the sections of the smooth path.

Preferably, in step S311, the number of segments of the smooth path is determined by the following expression according to the speed start value, the speed end value, and the preset speed gradient initial value:

where D is the number of segments of the smooth path, v₀Is a velocity start value, v_tδ v is a preset velocity gradient initial value for the velocity end value.

Preferably, in step S312, a speed value of each smooth path segment is determined according to the speed start value, the preset speed gradient initial value, and the number of segments of the smooth path:

v_i＝v₀+iδv

wherein v is_iFor the velocity value of the current smooth path segment, v₀The speed initial value is delta v, the preset speed gradient initial value is delta v, and the number of sections of the current smooth path section calculated from the starting end of the smooth path is i.

Preferably, after step S400, the method further comprises:

judging whether a sudden change interface of the depth domain layer velocity model is eliminated;

and when the abrupt interface of the depth domain layer speed model is not eliminated, correcting the preset initial value of the speed gradient, enabling the preset initial value of the speed gradient to be equal to the corrected value of the speed gradient, and returning to the step S300 to continuously correct the speed values of all sampling points on each smooth path.

According to another aspect of the present invention, there is provided a pre-stack depth migration processing method, including the steps of:

obtaining a depth domain layer velocity model of the eliminated abrupt interface according to the method for eliminating the abrupt interface of the velocity model;

and performing pre-stack depth migration processing on the seismic data by using the depth domain layer velocity model.

According to a further aspect of the invention, a storage medium is provided, on which a computer program is stored which, when being executed by a processor, carries out the steps of the method as described above.

Compared with the prior art, one or more embodiments in the above scheme can have the following advantages or beneficial effects:

1) by applying the method for eliminating the abrupt interface of the speed model, a buffer area is created in a preset buffer distance around the abrupt interface of the speed model of the depth domain layer, a plurality of smooth paths are constructed in the buffer area, and the speed smooth value of each sampling point on each smooth path is calculated, so that the speed value of each sampling point on the same smooth path is sequentially increased or decreased, the abrupt interface and the imaging false image or even false fault of the speed model of the depth domain layer are eliminated, and the precision of the speed model of the depth domain layer is improved;

2) the method for eliminating the abrupt interface of the speed model can smooth the depth domain layer speed model of the splicing or manual editing speed so as to quickly realize the speed editing and speed splicing of the speed model;

3) when the abrupt interface of the depth domain layer speed model is not eliminated, the preset speed gradient initial value is corrected, the preset speed gradient initial value is made to be equal to the speed gradient correction value so as to correct the speed value of each sampling point on each smooth path, and the speed value of each sampling point on each smooth path is continuously calculated by adjusting the preset speed gradient initial value and according to the adjusted preset speed gradient initial value until the abrupt interface of the depth domain layer speed model is eliminated.

Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by the practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention and not to limit the invention. In the drawings:

FIG. 1 is a flow chart illustrating a method for eliminating abrupt interfaces of velocity models according to an embodiment of the present invention;

FIG. 2 is a flow chart illustrating a method for eliminating abrupt interfaces of velocity models according to a second embodiment of the present invention;

FIG. 3 is a schematic diagram of a velocity model without eliminating abrupt interface contour lines according to a fourth embodiment of the present invention;

FIG. 4 is a schematic diagram of a velocity model with an abrupt interface contour eliminated according to a fourth embodiment of the present invention;

FIG. 5 is a schematic diagram of a velocity model without eliminating abrupt interface contour lines according to an embodiment of the present invention;

FIG. 6 shows an offset profile corresponding to a velocity model without eliminating abrupt interface contours according to an embodiment of the present invention;

FIG. 7 shows an offset profile corresponding to a velocity model with an abrupt interface contour eliminated according to a sixth embodiment of the present invention,

in the figure, 401-abrupt interface contour, 402-first boundary of buffer region, 403-second boundary of buffer region, 404-buffer region, 501-abrupt interface contour, 502-first boundary of buffer region, 503-second boundary of buffer region, 504-buffer region.

Detailed Description

The following detailed description of the embodiments of the present invention will be provided with reference to the drawings and examples, so that how to apply the technical means to solve the technical problems and achieve the technical effects can be fully understood and implemented. It should be noted that, as long as there is no conflict, the embodiments and the features of the embodiments of the present invention may be combined with each other, and the technical solutions formed are within the scope of the present invention.

Example one

In order to solve the technical problems in the prior art, the embodiment of the invention provides a method for eliminating a speed model abrupt interface.

Referring to fig. 1, the method for eliminating the abrupt interface of the velocity model in the embodiment includes the following steps:

s100, creating a buffer area within a preset buffer distance around a sudden change interface of the depth domain layer velocity model;

s200, constructing a plurality of smooth paths from a first boundary to a second boundary of the buffer area according to a preset direction;

s300, determining a speed smooth value of each sampling point on each smooth path according to the speed values of the sampling points at the two ends of each smooth path and a preset speed gradient initial value;

s400, taking the speed smooth value of each sampling point on each smooth path as the speed value of each sampling point, and enabling the speed value of each sampling point on the same smooth path to be sequentially increased or decreased so as to eliminate the abrupt interface of the depth domain layer speed model;

s500, judging whether the abrupt interface of the depth domain layer velocity model is eliminated: if yes, go to step S700; if not, executing step S600;

s600, when the abrupt interface of the depth domain layer speed model is not eliminated, correcting the preset initial value of the speed gradient, enabling the preset initial value of the speed gradient to be equal to the corrected value of the speed gradient, returning to the step S300, and continuously correcting the speed values of all sampling points on each smooth path;

and S700, keeping the speed value of each sampling point on each smooth path unchanged.

Example two

In order to solve the above technical problems in the prior art, an embodiment of the present invention provides a method for eliminating a speed model abrupt interface based on the first embodiment, wherein the method for eliminating the speed model abrupt interface of the first embodiment of the present invention is further improved from step S100 and step S300 in the first embodiment.

Referring to fig. 2, the method for eliminating the abrupt interface of the velocity model in the embodiment includes the following steps:

s110, forming a two-dimensional abrupt interface contour line according to an abrupt interface of the depth domain layer velocity model;

s120, taking a two-dimensional abrupt interface contour line as a boundary, and taking a region formed by sampling points with a distance not exceeding a preset buffer distance on two opposite sides of the boundary as a buffer region;

s200, constructing a plurality of smooth paths from a first boundary to a second boundary of the buffer area according to a preset direction;

s310, determining the number of segments of the smooth path and the speed value of each small segment of the smooth path according to the speed initial value, the speed end value and a preset speed gradient initial value by taking the speed value of the sampling point at the starting end of the smooth path as a speed initial value and the speed value of the sampling point at the ending end of the smooth path as a speed end value;

s320, taking the speed value of the small section of the smooth path as the speed smooth value of each sampling point on the small section of the smooth path;

s400, taking the speed smooth value of each sampling point on each smooth path as the speed value of each sampling point, and enabling the speed value of each sampling point on the same smooth path to be sequentially increased or decreased so as to eliminate the abrupt interface of the depth domain layer speed model;

s500, judging whether the abrupt interface of the depth domain layer velocity model is eliminated: if yes, go to step S700; if not, executing step S600;

s600, when the abrupt interface of the depth domain layer speed model is not eliminated, correcting the preset initial value of the speed gradient, enabling the preset initial value of the speed gradient to be equal to the corrected value of the speed gradient, returning to the step S310, and continuing to correct the speed value of each sampling point on each smooth path;

and S700, keeping the speed value of each sampling point on each smooth path unchanged.

EXAMPLE III

In order to solve the above technical problems in the prior art, the embodiment of the present invention provides a method for eliminating a speed model abrupt interface based on the second embodiment, wherein the method for eliminating a speed model abrupt interface of the second embodiment of the present invention is further improved from step S310 in the second embodiment.

S110, forming a two-dimensional abrupt interface contour line according to an abrupt interface of the depth domain layer velocity model;

the depth domain layer velocity model is obtained through the following steps:

picking up a velocity spectrum of the offset gather of the time domain to obtain a root mean square velocity of the time domain;

converting the root mean square speed of the time domain into the layer speed of the time domain by a DIX formula;

and converting the layer velocity of the time domain into a depth domain layer velocity model through time-depth conversion.

S120, taking a two-dimensional abrupt interface contour line as a boundary, and taking a region formed by sampling points with a distance not exceeding a preset buffer distance on two opposite sides of the boundary as a buffer region;

s200, constructing a plurality of smooth paths from a first boundary to a second boundary of the buffer area according to a preset direction, wherein the preset direction is vertical to the depth direction of the depth domain layer velocity model, such as the Z direction of FIG. 3;

s311, determining the number of segments of the smooth path according to the speed initial value, the speed end value and a preset speed gradient initial value by taking the speed value of the sample point at the starting end of the smooth path as the speed initial value and taking the speed value of the sample point at the ending end of the smooth path as the speed end value;

and determining the number of sections of the smooth path according to the speed initial value, the speed end value and a preset speed gradient initial value through the following expression:

where D is the number of segments of the smooth path, v₀Is a velocity start value, v_tδ v is a preset velocity gradient initial value for the velocity end value.

S312, determining the speed value of each small section of the smooth path according to the speed initial value, the preset speed gradient initial value and the number of the sections of the smooth path;

specifically, the speed value of each smooth path segment is determined according to the speed initial value, the preset speed gradient initial value and the number of the segments of the smooth path:

v_i＝v₀+iδv

in particular, v_iFor the velocity value of the current smooth path segment, v₀The speed initial value is delta v, the preset speed gradient initial value is delta v, and the number of sections of the current smooth path section calculated from the starting end of the smooth path is i.

S320, taking the speed value of the small section of the smooth path as the speed smooth value of each sampling point on the small section of the smooth path;

s400, taking the speed smooth value of each sampling point on each smooth path as the speed value of each sampling point, and enabling the speed value of each sampling point on the same smooth path to be sequentially increased or decreased so as to eliminate the abrupt interface of the depth domain layer speed model;

s500, judging whether the abrupt interface of the depth domain layer velocity model is eliminated: if yes, go to step S700; if not, executing step S600;

s600, when the abrupt interface of the depth domain layer speed model is not eliminated, correcting the preset initial value of the speed gradient, enabling the preset initial value of the speed gradient to be equal to the corrected value of the speed gradient, returning to the step S311, and continuously correcting the speed values of the sampling points on each smooth path;

and S700, keeping the speed value of each sampling point on each smooth path unchanged.

Example four

The third embodiment describes a case that the abrupt interface of the depth domain layer velocity model is formed by splicing the depth domain layer velocity models of two work areas.

The method for eliminating the abrupt interface of the speed model comprises the following steps:

picking up a velocity spectrum of the offset gathers of the time domains of the two work areas respectively to obtain root mean square velocities of the time domains of the two work areas;

converting the root mean square speed of the time domain of each work area into the layer speed of the time domain by a DIX formula;

converting the layer speed of the time domain of each work area into a depth domain layer speed model through time-depth conversion;

under the condition that the abrupt interface of the depth domain layer velocity model is formed by splicing the depth domain layer velocity models of the two work areas, the abrupt interface of the depth domain layer velocity model is formed at the splicing position;

forming a two-dimensional abrupt interface contour line, such as an X-Z two-dimensional abrupt interface contour line, according to an abrupt interface of the depth domain layer velocity model, referring to FIG. 3;

taking the X-Z two-dimensional abrupt interface contour line 401 of fig. 3 as a boundary, and taking a region formed by sampling points whose distances on two opposite sides of the boundary do not exceed a preset buffer distance as a buffer region 404, wherein the buffer region includes a first boundary 402 and a second boundary 403;

constructing a plurality of smooth paths from a first boundary to a second boundary of the buffer area according to a preset direction, such as the arrow direction in fig. 3;

taking the speed value of a sample point at the starting end of the smooth path (the sample point of the smooth path on the interface in the buffer area) as a speed starting value, taking the speed value of a sample point at the ending end of the smooth path (the sample point of the smooth path on the interface outside the buffer area) as a speed ending value, and determining the number of sections of the smooth path according to the speed starting value, the speed ending value and a preset speed gradient initial value;

for example, when the starting value of the speed on the same smooth path is 40m/s, the ending value of the speed is 50m/s, the initial value of the preset speed gradient is 1m/s, the number of segments of the smooth path is 10, and the speed values of each small segment of the smooth path are 41m/s, 42m/s, 43m/s, 44m/s, 45m/s, 46m/s, 47m/s, 48m/s, 49m/s and 50m/s in sequence from the starting end of the smooth path, and when 19 samples are uniformly distributed between the starting end sample of the smooth path and the starting end sample of the smooth path, the speed smoothing values of the samples from the starting end sample of the smooth path to the ending end sample of the smooth path are 41m/s, 42m/s in sequence, 42m/s, 43m/s, 44m/s, 45m/s, 46m/s, 47m/s, 48m/s, 49m/s, 50m/s, so that the speed values of the samples from the starting end of the smooth path to the ending end of the smooth path are 41m/s, 42m/s, 43m/s, 44m/s, 45m/s, 46m/s, 47m/s, 48m/s, 44m/s, 47m/s, 45m/s, 48m/s, 50m/s in this order, 49m/s, 50 m/s.

Judging whether a sudden change interface of the depth domain layer velocity model is eliminated: if yes, keeping the speed value of each sampling point on each smooth path unchanged; if not, the initial value of the preset velocity gradient is adjusted to be small, for example, 0.5m/s, at this time, the number of segments of the smooth path is 20, and the velocity values of each segment of the smooth path are 40.5m/s, 41m/s, 41.5m/s, 42m/s, 42.5m/s, 43m/s, 43.5m/s, 44m/s, 44.5m/s, 45m/s, 45.5m/s, 46m/s, 46.5m/s, 47m/s, 47.5m/s, 48m/s, 48.5m/s, 49m/s, 49.5m/s and 50m/s in sequence from the starting end of the smooth path to the ending end of the smooth path, and when 19 samples are uniformly distributed between the starting end of the smooth path and the starting end of the smooth path, the velocity values of the samples from the starting end of the smooth path to the ending end of the smooth path are 40.5m/s in sequence 41m/s, 41.5m/s, 42m/s, 42.5m/s, 43m/s, 43.5m/s, 44m/s, 44.5m/s, 45m/s, 45.5m/s, 46m/s, 46.5m/s, 47m/s, 47.5m/s, 48m/s, 48.5m/s, 49m/s and 49.5 m/s.

Judging whether the abrupt interface of the depth domain layer velocity model is eliminated again: if yes, keeping the speed value of each sampling point on each smooth path unchanged; if not, the preset initial value of the speed gradient is continuously adjusted to be small until the abrupt change interface of the depth domain layer speed model is eliminated, wherein fig. 4 is a speed model schematic diagram of the speed model abrupt change interface of fig. 3 is eliminated, and comparing fig. 3 with fig. 4, it can be known that the speed model eliminating the abrupt change interface of the speed model has no imaging artifacts and false faults.

EXAMPLE five

This embodiment describes a case where the method of the third embodiment is applied to manually edit a partial region of a depth domain layer velocity model of a work area.

The method for eliminating the abrupt interface of the speed model comprises the following steps:

picking up a velocity spectrum of the offset gathers of the time domain of the work area respectively to obtain a root mean square velocity of the time domain of the work area;

converting the root mean square speed of the time domain of the work area into the layer speed of the time domain by a DIX formula;

converting the layer speed of the time domain of the work area into a depth domain layer speed model through time-depth conversion;

under the condition of manually editing a partial area of a depth domain layer velocity model of a work area, forming a mutation interface of the depth domain layer velocity model at the boundary of an editing area and a non-editing area;

forming a two-dimensional abrupt interface contour line, such as an X-Y two-dimensional abrupt interface contour line, according to an abrupt interface of the depth domain layer velocity model, referring to FIG. 5;

taking the X-Y two-dimensional abrupt interface contour line 501 of fig. 5 as a boundary, and taking a region formed by sampling points whose distances on two opposite sides of the boundary do not exceed a preset buffer distance as a buffer region 504, wherein the buffer region includes a first boundary 502 and a second boundary 503;

constructing a plurality of smooth paths from a first boundary to a second boundary of the buffer area according to a preset direction, such as an arrow direction in fig. 5;

taking the speed value of a sample point at the starting end of the smooth path (the sample point of the smooth path on the interface in the buffer area) as a speed starting value, taking the speed value of a sample point at the ending end of the smooth path (the sample point of the smooth path on the interface outside the buffer area) as a speed ending value, and determining the number of sections of the smooth path according to the speed starting value, the speed ending value and a preset speed gradient initial value;

for example, when the starting value of the speed on the same smooth path is 40m/s, the ending value of the speed is 50m/s, the initial value of the preset speed gradient is 1m/s, the number of segments of the smooth path is 10, and the speed values of each small segment of the smooth path are 41m/s, 42m/s, 43m/s, 44m/s, 45m/s, 46m/s, 47m/s, 48m/s, 49m/s and 50m/s in sequence from the starting end of the smooth path, and when 19 samples are uniformly distributed between the starting end sample of the smooth path and the starting end sample of the smooth path, the speed smoothing values of the samples from the starting end sample of the smooth path to the ending end sample of the smooth path are 41m/s, 42m/s in sequence, 42m/s, 43m/s, 44m/s, 45m/s, 46m/s, 47m/s, 48m/s, 49m/s, 50m/s, so that the speed values of the samples from the starting end of the smooth path to the ending end of the smooth path are 41m/s, 42m/s, 43m/s, 44m/s, 45m/s, 46m/s, 47m/s, 48m/s, 44m/s, 47m/s, 45m/s, 48m/s, 50m/s in this order, 49m/s, 50 m/s.

Judging whether a sudden change interface of the depth domain layer velocity model is eliminated: if yes, keeping the speed value of each sampling point on each smooth path unchanged; if not, the initial value of the preset velocity gradient is adjusted to be small, for example, 0.5m/s, at this time, the number of segments of the smooth path is 20, and the velocity values of each segment of the smooth path are 40.5m/s, 41m/s, 41.5m/s, 42m/s, 42.5m/s, 43m/s, 43.5m/s, 44m/s, 44.5m/s, 45m/s, 45.5m/s, 46m/s, 46.5m/s, 47m/s, 47.5m/s, 48m/s, 48.5m/s, 49m/s, 49.5m/s and 50m/s in sequence from the starting end of the smooth path to the ending end of the smooth path, and when 19 samples are uniformly distributed between the starting end of the smooth path and the starting end of the smooth path, the velocity values of the samples from the starting end of the smooth path to the ending end of the smooth path are 40.5m/s in sequence 41m/s, 41.5m/s, 42m/s, 42.5m/s, 43m/s, 43.5m/s, 44m/s, 44.5m/s, 45m/s, 45.5m/s, 46m/s, 46.5m/s, 47m/s, 47.5m/s, 48m/s, 48.5m/s, 49m/s and 49.5 m/s.

Judging whether the abrupt interface of the depth domain layer velocity model is eliminated again: if yes, keeping the speed value of each sampling point on each smooth path unchanged; if not, the initial value of the preset speed gradient is continuously adjusted to be small until the abrupt interface of the depth domain layer speed model is eliminated.

EXAMPLE six

In order to solve the above technical problems in the prior art, an embodiment of the present invention further provides a prestack depth migration processing method.

The prestack depth migration processing method of the embodiment includes the following steps:

obtaining a depth domain layer velocity model of the eliminated abrupt interface according to the method for eliminating the abrupt interface of the velocity model;

and performing pre-stack depth migration processing on the seismic data by using the depth domain layer velocity model.

Comparing fig. 6 and fig. 7, it can be seen that the depth domain layer velocity model having the abrupt interface of the velocity model causes the phenomenon that the offset profile has the false fault, and the offset profile corresponding to the depth domain layer velocity model having the eliminated abrupt interface has no false fault.

EXAMPLE seven

In order to solve the above technical problems in the prior art, an embodiment of the present invention further provides a storage medium.

The storage medium of the present embodiment has a computer program stored thereon, which when executed by a processor implements the steps of the method for eliminating the abrupt interface of the velocity model in the above embodiments.

Although the embodiments of the present invention have been described above, the above description is only for the convenience of understanding the present invention, and is not intended to limit the present invention. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.