阅读说明：本技术 基于倾角约束的叠前深度偏移方法及装置 (Pre-stack depth migration method and device based on dip angle constraint ) 是由 张恩嘉 金德刚 何光明 熊晶璇 王光银 陈三平 于 2020-05-07 设计创作，主要内容包括：本发明提供了一种基于倾角约束的叠前深度偏移方法及装置,该方法包括：对目标区域的地震数据进行叠前深度偏移,获得叠前倾角成像道集；对所述叠前倾角成像道集进行叠加成像,获得成像剖面数据；根据目标区域的真地层倾角和成像剖面数据,获得带有倾角约束的叠前倾角成像道集；对带有倾角约束的叠前倾角成像道集进行叠加成像,获得更新的成像剖面数据。本发明可以基于倾角约束进叠前深度偏移,成像信噪比低。(The invention provides a pre-stack depth migration method and a device based on dip angle constraint, wherein the method comprises the following steps: carrying out prestack depth migration on the seismic data of the target area to obtain a prestack dip angle imaging gather; carrying out superposition imaging on the pre-stack dip angle imaging gather to obtain imaging section data; acquiring a prestack dip angle imaging gather with dip angle constraint according to the true formation dip angle and the imaging section data of the target area; and carrying out superposition imaging on the pre-stack dip angle imaging gather with the dip angle constraint to obtain updated imaging section data. The invention can carry out prestack depth migration based on inclination angle constraint and has low imaging signal-to-noise ratio.)

1. A pre-stack depth migration method based on dip angle constraint is characterized by comprising the following steps:

carrying out prestack depth migration on the seismic data of the target area to obtain a prestack dip angle imaging gather;

carrying out superposition imaging on the pre-stack dip angle imaging gather to obtain imaging section data;

acquiring a prestack dip angle imaging gather with dip angle constraint according to the true formation dip angle and the imaging section data of the target area;

and carrying out superposition imaging on the pre-stack dip angle imaging gather with the dip angle constraint to obtain updated imaging section data.

2. The dip constraint-based prestack depth migration method of claim 1, further comprising:

and obtaining the true formation dip angle of the target area through plane wave decomposition.

3. The dip constraint-based prestack depth migration method of claim 1, wherein obtaining a prestack dip imaging gather with dip constraints based on true stratigraphic dips and imaging profile data for a target region comprises:

determining the range of an inclined angle imaging area according to the true formation inclined angle when the imaging value at the imaging point in the imaging section data tends to be stable and reaches a maximum value;

and determining a constraint range of the pre-stack dip angle imaging gather based on the range of the dip angle imaging area, wherein the constraint range of the pre-stack dip angle imaging gather is used for constructing the pre-stack dip angle imaging gather with dip angle constraint.

4. The tilt-constraint-based prestack depth migration method of claim 3, characterized in that the tilt imaging zone ranges from [ theta- β ]₁,θ+β₂]Where theta is the true formation dip of the target zone, theta- β₁Is the initial tilt angle value of the tilt angle imaging zone, theta + β₂An end tilt value for the tilt imaging zone;

the constraint range of the prestack dip imaging gather is [ β ]₁,β₂]。

5. A pre-stack depth migration apparatus based on dip angle constraint, comprising:

the system comprises a first module, a second module and a third module, wherein the first module is used for carrying out prestack depth migration on seismic data of a target area to obtain a prestack dip angle imaging gather;

the second module is used for carrying out superposition imaging on the pre-stack dip angle imaging gather to obtain imaging section data;

the third module is used for obtaining a pre-stack dip angle imaging gather with dip angle constraint according to the true formation dip angle and the imaging section data of the target area;

and the fourth module is used for carrying out superposition imaging on the pre-stack dip angle imaging gather with the dip angle constraint to obtain updated imaging section data.

6. The pre-stack depth migration apparatus based on tilt angle constraint of claim 5, further comprising a fifth module for:

and obtaining the true formation dip angle of the target area through plane wave decomposition.

7. The dip constraint-based prestack depth migration apparatus of claim 5, wherein the third module is specifically configured to:

determining the range of an inclined angle imaging area according to the true formation inclined angle when the imaging value at the imaging point in the imaging section data tends to be stable and reaches a maximum value;

and determining a constraint range of the pre-stack dip angle imaging gather based on the range of the dip angle imaging area, wherein the constraint range of the pre-stack dip angle imaging gather is used for constructing the pre-stack dip angle imaging gather with dip angle constraint.

8. The tilt-constraint-based prestack depth migration apparatus of claim 7, wherein the tilt imaging zone has a range of [ theta- β ]₁,θ+β₂]Where theta is the true formation dip of the target zone, theta- β₁Is the initial tilt angle value of the tilt angle imaging zone, theta + β₂An end tilt value for the tilt imaging zone;

the constraint range of the prestack dip imaging gather is [ β ]₁,β₂]。

9. A computer 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 of any of claims 1 to 4 when executing the computer program.

10. A computer-readable storage medium, characterized in that the computer-readable storage medium stores a computer program for executing the method of any one of claims 1 to 4.

Technical Field

The invention relates to the technical field of seismic exploration, in particular to a prestack depth migration method and device based on dip angle constraint.

Background

In a complex mountain structure area, due to the fact that the speed is changed violently in the transverse direction, pre-stack depth migration imaging can effectively improve the structure precision, and high-quality imaging data are provided for subsequent explanation. However, the same migration aperture is adopted in the conventional prestack depth migration process, and for the underground structure with large inclination angle and good imaging, the aperture is often selected to be large and brings noise, so that the imaging signal to noise ratio is reduced.

And aiming at the noise brought by the large offset aperture, necessary constraint is introduced to reduce the noise and improve the imaging signal-to-noise ratio. The introduced constraint condition is very critical how to constrain the offset noise brought in by the overlarge aperture and ensure the imaging of the large inclination angle. And the current lack of effective constraint conditions of prestack depth migration enables the signal-to-noise ratio of the final prestack depth migration imaging to be low.

Disclosure of Invention

The embodiment of the invention provides a dip-constraint-based prestack depth migration method, which is used for prestack depth migration based on dip constraint and has low imaging signal-to-noise ratio and comprises the following steps:

carrying out prestack depth migration on the seismic data of the target area to obtain a prestack dip angle imaging gather;

carrying out superposition imaging on the pre-stack dip angle imaging gather to obtain imaging section data;

acquiring a prestack dip angle imaging gather with dip angle constraint according to the true formation dip angle and the imaging section data of the target area;

and carrying out superposition imaging on the pre-stack dip angle imaging gather with the dip angle constraint to obtain updated imaging section data.

The embodiment of the invention provides a pre-stack depth migration device based on dip angle constraint, which is used for pre-stack depth migration based on dip angle constraint and has low imaging signal-to-noise ratio, and comprises the following components:

the system comprises a first module, a second module and a third module, wherein the first module is used for carrying out prestack depth migration on seismic data of a target area to obtain a prestack dip angle imaging gather;

the second module is used for carrying out superposition imaging on the pre-stack dip angle imaging gather to obtain imaging section data;

the third module is used for obtaining a pre-stack dip angle imaging gather with dip angle constraint according to the true formation dip angle and the imaging section data of the target area;

and the fourth module is used for carrying out superposition imaging on the pre-stack dip angle imaging gather with the dip angle constraint to obtain updated imaging section data.

The embodiment of the present invention further provides a computer device, which includes a memory, a processor, and a computer program stored in the memory and executable on the processor, and when the processor executes the computer program, the processor implements the pre-stack depth migration method based on the tilt constraint.

An embodiment of the present invention further provides a computer-readable storage medium, which stores a computer program for executing the pre-stack depth migration method based on the dip constraint.

In the embodiment of the invention, pre-stack depth migration is carried out on seismic data of a target area to obtain a pre-stack dip angle imaging gather; carrying out superposition imaging on the pre-stack dip angle imaging gather to obtain imaging section data; acquiring a prestack dip angle imaging gather with dip angle constraint according to the true formation dip angle and the imaging section data of the target area; and carrying out superposition imaging on the pre-stack dip angle imaging gather with the dip angle constraint to obtain updated imaging section data. In the process, the pre-stack dip angle imaging gather with the dip angle constraint is obtained through the true stratigraphic dip angle and the imaging section data of the target area, so that the final pre-stack dip angle imaging gather has the dip angle constraint, and when superposition imaging is carried out, noise can be reduced, and the imaging signal-to-noise ratio is improved.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts. In the drawings:

FIG. 1 is a flow chart of a pre-stack depth migration method based on dip constraints in an embodiment of the present invention;

FIG. 2 is a schematic view of the computation of a prestack dip imaging gather in an embodiment of the invention;

FIG. 3 is a detailed flowchart of a pre-stack depth migration method based on dip angle constraint according to an embodiment of the present invention;

FIG. 4 is a schematic diagram of a pre-stack depth migration apparatus based on dip angle constraint according to an embodiment of the present invention;

FIG. 5 is a diagram of a computer device in an embodiment of the invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the embodiments of the present invention are further described in detail below with reference to the accompanying drawings. The exemplary embodiments and descriptions of the present invention are provided to explain the present invention, but not to limit the present invention.

In the description of the present specification, the terms "comprising," "including," "having," "containing," and the like are used in an open-ended fashion, i.e., to mean including, but not limited to. Reference to the description of the terms "one embodiment," "a particular embodiment," "some embodiments," "for example," etc., means that a particular feature, structure, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the application. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. The sequence of steps involved in the embodiments is for illustrative purposes to illustrate the implementation of the present application, and the sequence of steps is not limited and can be adjusted as needed.

Fig. 1 is a flowchart of a pre-stack depth migration method based on dip angle constraint in an embodiment of the present invention, as shown in fig. 1, the method includes:

101, performing prestack depth migration on seismic data of a target area to obtain a prestack dip imaging gather;

102, carrying out superposition imaging on the pre-stack dip angle imaging gather to obtain imaging section data;

103, acquiring a pre-stack dip angle imaging gather with dip angle constraint according to the true stratigraphic dip angle and the imaging section data of the target area;

and step 104, carrying out superposition imaging on the pre-stack dip angle imaging gather with the dip angle constraint to obtain updated imaging section data.

In the embodiment of the invention, the pre-stack dip angle imaging gather with dip angle constraint is obtained through the true stratigraphic dip angle and the imaging section data of the target area, so that the final pre-stack dip angle imaging gather has dip angle constraint, and when superposition imaging is carried out, noise can be reduced and the imaging signal-to-noise ratio can be improved.