Pre-stack crack prediction method, device and product

Abstract

The present invention discloses a method, device, and product for predicting pre-stack fractures, relating to the technical field of seismic data analysis. The method includes determining the formation dip of a target layer; inverting AVO attributes to obtain the AVO gradient of seismic data in all directions; determining the maximum AVO gradient difference corresponding to different directions based on the AVO gradient of the seismic data in all directions; performing a two-directional streamer acquisition simulation on the geological model of the target layer to obtain two-directional seismic forward simulation data of the target layer; performing AVO attribute inversion on the two-directional seismic forward simulation data to obtain the AVO gradient of the two-directional seismic forward simulation data; determining the AVO gradient difference of the two-directional seismic forward simulation data; and estimating a correction factor for the AVO gradient difference based on the AVO gradient difference of the two-directional seismic forward simulation data and the formation dip, and correcting the maximum AVO gradient difference. The method, device, and product disclosed in the present invention can improve the accuracy of pre-stack fracture prediction.

Description

Technical Field

[0001] The present invention belongs to the technical field of seismic data analysis, and in particular relates to a method, device and product for predicting pre-stack fractures. Background Art

[0002] Marine streamer dual-azimuth seismic acquisition and processing technology utilizes two streamer data sets from different acquisition azimuths within the same area. Through targeted processing, it can produce a fusion of the two-azimuth seismic data. This dual-azimuth acquisition and fusion processing method improves seismic illumination, increases seismic coverage, and effectively enhances seismic imaging quality. Analysis shows that dual-azimuth acquisition can effectively compensate for the shortcomings of single-azimuth acquisition and facilitates imaging of buried-mountain tops and internal faults.

[0003] However, for high- and steep-angle formations, there are obvious differences in seismic data collected at different azimuths. The data differences caused by this illumination interfere with the azimuthal anisotropy detection, making it impossible to accurately predict and analyze the development of fractures in underground rock formations based on azimuthal anisotropy.

[0004] Therefore, how to provide an effective solution to accurately predict and analyze the development of cracks in underground rock formations has become a problem that needs to be solved urgently in the existing technology. Summary of the Invention

[0005] The purpose of the present invention is to provide a method, device and product for predicting pre-stack cracks, so as to solve the above-mentioned problems existing in the prior art.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] In a first aspect, the present invention provides a method for predicting prestack cracks, comprising:

[0008] Determining the stratigraphic inclination of the target layer based on stratigraphic position information of the target layer in the target area;

[0009] Performing AVO attribute inversion on the multi-azimuth seismic data of the target area to obtain AVO gradients of seismic data in each azimuth of the multi-azimuth seismic data;

[0010] Based on the AVO gradients of the seismic data in each orientation, determining the maximum AVO gradient differences corresponding to different orientations in the multi-azimuth seismic data;

[0011] Perform bi-directional streamer acquisition simulation on the established geological model of the target layer to obtain bi-directional seismic forward simulation data of the target layer;

[0012] Perform AVO attribute inversion on the bi-directional seismic forward simulation data of the target layer to obtain the AVO gradient of the bi-directional seismic forward simulation data;

[0013] Based on the AVO gradient of the two-orientation seismic forward modeling data, determining the AVO gradient difference corresponding to the two-orientation seismic forward modeling data;

[0014] estimating a correction factor for the AVO gradient difference based on the AVO gradient difference corresponding to the two-orientation seismic forward modeling data and the formation dip;

[0015] The maximum AVO gradient difference is corrected based on the correction factor to obtain a corrected AVO gradient difference, so as to predict the fracture development of the target layer based on the corrected AVO gradient difference.

[0016] Based on the above disclosure, the present invention determines the formation dip of the target layer based on the formation position information of the target layer in the target area; performs AVO attribute inversion on the multi-azimuth seismic data of the target area to obtain the AVO gradient of the seismic data in each orientation in the multi-azimuth seismic data; determines the maximum AVO gradient difference corresponding to different orientations in the multi-azimuth seismic data based on the AVO gradient of the seismic data in each orientation; performs two-azimuth streamer acquisition simulation on the established geological model of the target layer to obtain two-azimuth seismic forward simulation data of the target layer; performs AVO attribute inversion on the two-azimuth seismic forward simulation data of the target layer to obtain the AVO gradient of the two-azimuth seismic forward simulation data; determines the AVO gradient difference corresponding to the two-azimuth seismic forward simulation data based on the AVO gradient of the two-azimuth seismic forward simulation data; estimates a correction factor for the AVO gradient difference based on the AVO gradient difference corresponding to the two-azimuth seismic forward simulation data and the formation dip; corrects the maximum AVO gradient difference based on the correction factor to obtain a corrected AVO gradient difference, so as to determine the fracture development status of the target layer based on the corrected AVO gradient difference. In this way, when predicting pre-stack fractures, based on the characteristic that the difference between the seismic data in two azimuths has a large correlation with the formation dip, a correction factor related to the AVO gradient difference in both azimuths and the formation dip can be calculated, and the correction factor can be used to correct the maximum AVO gradient difference corresponding to different azimuths to reduce the impact of the azimuthal anisotropy on the high and steep dip formations on both wings due to the difference in the acquisition illumination of both sides, so as to make a more accurate prediction and analysis of the development of fractures in the underground rock formation based on the azimuthal anisotropy, thereby improving the accuracy of pre-stack fracture prediction.

[0017] In one possible design, determining the formation dip of the target layer based on the formation position information of the target layer in the target area includes:

[0018] compiling a structural map of the target layer based on the stratigraphic position information of the target layer;

[0019] The formation dip of the target layer is calculated based on the structure of the target layer.

[0020] In one possible design, compiling a structural map of the target layer based on the stratigraphic location information of the target layer includes:

[0021] If the stratigraphic position information of the target layer is stratigraphic position information of a depth domain layer, compiling a structural map of the target layer based on the stratigraphic position information of the depth domain layer;

[0022] If the stratigraphic position information of the target layer is the stratigraphic position information of the time domain layer, the stratigraphic position information of the time domain layer is converted into the stratigraphic position information of the depth domain layer, and then a structural map of the target layer is compiled based on the stratigraphic position information of the depth domain layer obtained by the conversion.

[0023] In one possible design, before performing a dual-azimuth streamer acquisition simulation on the established geological model of the target layer, the method further includes:

[0024] A geological model of the target layer is established based on the horizon position, fault information and rock physical parameters of the target layer.

[0025] In one possible design, before correcting the maximum AVO gradient difference based on the correction factor, the method further includes:

[0026] Determining whether the maximum AVO gradient difference and the formation dip satisfy a predefined positive correlation;

[0027] Correcting the maximum AVO gradient difference based on the correction factor includes:

[0028] If the maximum AVO gradient difference and the formation dip satisfy a predefined positive correlation, the maximum AVO gradient difference is corrected based on the correction factor.

[0029] In one possible design, the correction factor for the AVO gradient difference is a = D m12 / H Dip , where D m12 It represents the AVO gradient difference corresponding to the two-orientation seismic forward modeling data, H Dip Indicates the dip angle of the formation.

[0030] In one possible design, the corrected AVO gradient difference is D = D n / (a×H Dip ), where D n represents the maximum AVO gradient difference.

[0031] In a second aspect, the present invention provides a device for predicting pre-stack cracks, comprising:

[0032] A first determining unit is configured to determine a stratum dip angle of a target layer based on stratum position information of the target layer in the target area;

[0033] A first inversion unit is configured to perform AVO attribute inversion on the multi-azimuth seismic data of the target area to obtain AVO gradients of seismic data in each azimuth of the multi-azimuth seismic data;

[0034] A second determining unit is configured to determine the maximum AVO gradient difference corresponding to different directions in the multi-directional seismic data based on the AVO gradient of the seismic data in each direction;

[0035] A simulation unit is used to simulate bi-directional streamer acquisition on the established geological model of the target layer to obtain bi-directional seismic forward simulation data of the target layer;

[0036] The second inversion unit is used to perform AVO attribute inversion on the bi-directional seismic forward simulation data of the target layer to obtain the AVO gradient of the bi-directional seismic forward simulation data;

[0037] A third determining unit is configured to determine an AVO gradient difference corresponding to the two-orientation seismic forward modeling data based on the AVO gradient of the two-orientation seismic forward modeling data;

[0038] an estimating unit, configured to estimate a correction factor for the AVO gradient difference based on the AVO gradient difference corresponding to the two-orientation seismic forward modeling data and the formation dip;

[0039] The correction unit is used to correct the maximum AVO gradient difference based on the correction factor to obtain a corrected AVO gradient difference, so as to predict the fracture development of the target layer based on the corrected AVO gradient difference.

[0040] In a third aspect, the present invention provides another device for predicting pre-stack cracks, comprising a memory, a processor, and a transceiver that are communicatively connected in sequence, wherein the memory is used to store a computer program, the transceiver is used to send and receive messages, and the processor is used to read the computer program and execute the method for predicting pre-stack cracks as described in the first aspect or any possible design of the first aspect.

[0041] In a fourth aspect, the present invention provides a computer-readable storage medium having instructions stored thereon. When the instructions are executed on a computer, the method for predicting pre-stack cracks according to the first aspect or any possible design of the first aspect is executed.

[0042] In a fifth aspect, the present invention provides a computer program product comprising instructions, which, when executed on a computer, causes the computer to execute the method for predicting pre-stack cracks as described in the first aspect or any possible design of the first aspect.

[0043] Beneficial effects:

[0044] The pre-stack fracture prediction method, device and product provided by the present invention can calculate the correction factor related to the two-azimuth AVO gradient difference and the formation dip based on the characteristic that the difference between the two-azimuth seismic data has a large correlation with the formation dip when predicting pre-stack fractures, and use the correction factor to correct the maximum AVO gradient difference corresponding to different azimuths to reduce the influence of the azimuthal anisotropy of the high-steep dip formations on the two wings due to the difference in the acquisition illumination of the two sides, so as to make a more accurate prediction and analysis of the development of fractures in the underground rock formation based on the azimuthal anisotropy, improve the accuracy of pre-stack fracture prediction, and facilitate application and promotion. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 A flowchart of a method for predicting prestack fractures provided in an embodiment of the present application;

[0046] Figure 2 The structure diagram of the target layer compiled in the embodiment of the present application;

[0047] Figure 3 A schematic diagram of bi-directional seismic forward modeling data of a target layer obtained through bi-directional streamer acquisition simulation provided in an embodiment of the present application;

[0048] Figure 4 A schematic diagram of the target layer before and after correction of the maximum AVO gradient difference provided in an embodiment of the present application;

[0049] Figure 5 A schematic block diagram of a device for predicting pre-stack cracks provided in an embodiment of the present application;

[0050] Figure 6 This is a schematic block diagram of another pre-stack crack prediction device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0051] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the present invention will be briefly introduced below in conjunction with the drawings and the description of the embodiments or the prior art. Obviously, the following description of the structure of the drawings is only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work. It should be noted that the description of these embodiments is used to help understand the present invention, but does not constitute a limitation of the present invention.

[0052] It should be understood that although the terms "first," "second," etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element can be referred to as a second element, and similarly, a second element can be referred to as a first element without departing from the scope of the exemplary embodiments of the present invention.

[0053] It should be understood that the term "and / or" that may appear in this document is merely a description of the association relationship between associated objects, indicating that three relationships may exist. For example, A and / or B may indicate three situations: A exists alone, B exists alone, and A and B exist at the same time. The term " / and" that may appear in this document describes another type of association object relationship, indicating that two relationships may exist. For example, A / and B may indicate two situations: A exists alone, and A and B exist alone. In addition, the character " / " that may appear in this document generally indicates that the previous and subsequent associated objects are in an "or" relationship.

[0054] In order to accurately predict and analyze the development of cracks in underground rock formations, an embodiment of the present application provides a pre-stack crack prediction method, device and product. The pre-stack crack prediction method, device and product can reduce the impact of azimuthal anisotropy on the high and steep angle strata on both sides due to the difference in acquisition illumination on both sides, so as to more accurately predict and analyze the development of cracks in underground rock formations based on azimuthal anisotropy.

[0055] The method for predicting pre-stack fractures provided in the embodiment of the present application can be applied to a user terminal. It is understood that the execution subject does not constitute a limitation on the embodiment of the present application.

[0056] The following is a detailed description of the method for predicting pre-stack cracks provided in the embodiments of the present application.

[0057] like Figure 1 , which is a flow chart of a method for predicting pre-stack cracks provided in the first aspect of an embodiment of the present application. The method for predicting pre-stack cracks may include, but is not limited to, the following steps S101 - S108 .

[0058] Step S101: Determine the stratigraphic dip of the target layer based on stratigraphic position information of the target layer in the target area.

[0059] In an embodiment of the present application, a structural map of the target layer can be compiled based on the stratigraphic position information of the target layer, and then the stratigraphic dip of the target layer can be calculated based on the structure of the target layer. When compiling the structural map of the target layer, the structural map can be compiled using professional geological modeling software, such as Petrel (Petrel is a software owned by Schlumberger. It is a three-dimensional visual modeling software that integrates many functions such as seismic interpretation, structural modeling, lithofacies modeling, reservoir property modeling, reservoir numerical simulation display, virtual reality, etc.).

[0060] Specifically, when compiling a structural map of a target layer, if the stratigraphic location information of the target layer is stratigraphic location information of a depth-domain layer, the structural map of the target layer can be compiled directly based on the stratigraphic location information of the depth-domain layer. If the stratigraphic location information of the target layer is stratigraphic location information of a time-domain layer, the stratigraphic location information of the time-domain layer can be first converted into stratigraphic location information of a depth-domain layer, and then the structural map of the target layer can be compiled based on the stratigraphic location information of the depth-domain layer obtained by the conversion.

[0061] After compiling the structural map of the target layer, the stratigraphic dip of the target layer can be calculated based on the structural map.

[0062] like Figure 2 As shown, it is a structural diagram of a target layer compiled according to an embodiment of the present application.

[0063] Step S102: Perform AVO attribute inversion on the multi-azimuth seismic data of the target area to obtain the AVO gradient of the seismic data in each azimuth in the multi-azimuth seismic data.

[0064] Multi-azimuth seismic data refers to seismic data collected from different azimuths. AVO (Amplitude Versus Offset) attribute inversion is a technique for identifying lithology and fluid properties by analyzing the variation of amplitude with offset (or angle of incidence) on pre-stack seismic data. It will not be described in detail in the implementation of this application.

[0065] The multi-azimuth seismic data may be, but is not limited to, seismic data in 4 directions, seismic data in 6 directions, or seismic data in 8 directions, etc. In the embodiment of the present application, the multi-azimuth seismic data is seismic data in 6 directions, from which the AVO gradient of the seismic data in 6 directions can be calculated.

[0066] Step S103: Based on the AVO gradients of the seismic data in each orientation, the maximum AVO gradient differences corresponding to different orientations in the multi-orientation seismic data are determined.

[0067] Specifically, the AVO gradients of the seismic data in each orientation can be subtracted from each other to calculate the AVO gradient differences corresponding to different orientations, and the largest AVO gradient difference is selected as the maximum AVO gradient difference corresponding to different orientations in the multi-azimuth seismic data.

[0068] Step S104: Perform a two-azimuth streamer acquisition simulation on the established geological model of the target layer to obtain two-azimuth seismic forward simulation data of the target layer.

[0069] In the embodiment of the present application, a geological model of the target layer can be established based on the horizon position, fault information of the target layer, and rock physical parameters of the target layer. Then, a two-azimuth streamer acquisition simulation is performed on the established geological model of the target layer to obtain two-azimuth seismic forward simulation data for the target layer.

[0070] The horizon of the target layer may refer to the three-dimensional shape of the target layer, the fault information of the target layer may include but is not limited to the dip and inclination of the target layer, and the rock physical parameter of the target layer may be the longitudinal wave velocity of the target layer.

[0071] Dual-azimuth streamer acquisition simulation refers to the simulation of offshore seismic exploration, in which two or more seismic acquisition cables are used to collect seismic data in two different directions.

[0072] like Figure 3 As shown, a schematic diagram of the bi-directional seismic forward modeling data of the target layer obtained by performing bi-directional streamer acquisition simulation on the geological model of the established target layer is shown. The left and right sides of the figure respectively show the seismic forward modeling data of two different directions.

[0073] Step S105: Perform AVO attribute inversion on the two-azimuth seismic forward modeling data of the target layer to obtain the AVO gradient of the two-azimuth seismic forward modeling data.

[0074] Specifically, by performing AVO attribute inversion on the bi-directional seismic forward simulation data of the target layer, the AVO gradients of the seismic forward simulation data in the two directions, that is, the AVO gradients of the seismic wave data in the two directions, can be obtained.

[0075] Step S106: Based on the AVO gradients of the two-azimuth seismic forward modeling data, determine the AVO gradient differences corresponding to the two-azimuth seismic forward modeling data.

[0076] Specifically, the AVO gradients of the seismic forward modeling data in two directions may be subtracted to obtain the AVO gradient difference corresponding to the seismic forward modeling data in the two directions.

[0077] Step S107: Estimate the correction factor of the AVO gradient difference based on the AVO gradient difference and the formation dip corresponding to the two-orientation seismic forward modeling data.

[0078] The correction factor for the AVO gradient difference can be expressed as a=D m12 / H Dip , where D m12 It represents the AVO gradient difference corresponding to the forward modeling data of the two-position earthquake, H Dip Indicates the dip angle of the formation.

[0079] Step S108: Correcting the maximum AVO gradient difference based on the correction factor to obtain a corrected AVO gradient difference, so as to predict the fracture development of the target layer based on the corrected AVO gradient difference.

[0080] The corrected AVO gradient difference can be expressed as D = D n / (a×H Dip ), where D n represents the maximum AVO gradient difference.

[0081] In practice, there is a positive correlation between the difference in AVO gradients of seismic data across multiple orientations and the formation dip. That is, the greater the formation dip, the greater the difference in AVO gradients of the seismic data across multiple orientations. Therefore, in one or more embodiments, before correcting the maximum AVO gradient difference based on the correction factor, it may be determined whether the maximum AVO gradient difference and the formation dip satisfy a predefined positive correlation. If so, the maximum AVO gradient difference may be corrected based on the correction factor. If not, the correction factor and the maximum AVO gradient difference corresponding to different orientations in the multi-azimuth seismic data are recalculated. This predefined positive correlation may be set empirically.

[0082] like Figure 4 The figure shows the target layer before and after the maximum AVO gradient difference is corrected. Figure 4 (a) is a schematic diagram of the target layer before the maximum AVO gradient difference is corrected, and (b) is a schematic diagram of the target layer after the maximum AVO gradient difference is corrected.

[0083] After obtaining the corrected AVO gradient difference, the fracture development of the target layer can be predicted based on the corrected AVO gradient difference. The larger the AVO gradient difference, the more developed the fractures, that is, the more fractures there are.

[0084] The present invention provides a method for predicting pre-stack fractures. The method comprises the following steps: determining the formation dip of a target layer based on formation position information of a target layer in a target area; performing AVO attribute inversion on multi-azimuth seismic data of the target area to obtain AVO gradients of seismic data in each orientation in the multi-azimuth seismic data; determining the maximum AVO gradient difference corresponding to different orientations in the multi-azimuth seismic data based on the AVO gradients of the seismic data in each orientation; performing two-azimuth streamer acquisition simulation on an established geological model of the target layer to obtain two-azimuth seismic forward modeling data of the target layer; performing AVO attribute inversion on the two-azimuth seismic forward modeling data of the target layer to obtain AVO gradients of the two-azimuth seismic forward modeling data; determining the AVO gradient difference corresponding to the two-azimuth seismic forward modeling data based on the AVO gradients of the two-azimuth seismic forward modeling data; estimating a correction factor for the AVO gradient difference based on the AVO gradient difference corresponding to the two-azimuth seismic forward modeling data and the formation dip; and correcting the maximum AVO gradient difference based on the correction factor to obtain a corrected AVO gradient difference, so as to determine the fracture development status of the target layer based on the corrected AVO gradient difference. In this way, when predicting pre-stack fractures, based on the characteristic that the difference between the seismic data in two azimuths has a large correlation with the formation dip, a correction factor related to the AVO gradient difference in both azimuths and the formation dip can be calculated, and the correction factor can be used to correct the maximum AVO gradient difference corresponding to different azimuths to reduce the impact of the azimuthal anisotropy on the high and steep dip formations on both wings due to the difference in the acquisition illumination of both sides, so as to make a more accurate prediction and analysis of the development of fractures in the underground rock formation based on the azimuthal anisotropy, improve the accuracy of pre-stack fracture prediction, and facilitate practical application and promotion.

[0085] See also Figure 5 A second aspect of an embodiment of the present application provides a device for predicting pre-stack cracks, the device comprising:

[0086] A first determining unit is configured to determine a stratum dip angle of a target layer based on stratum position information of the target layer in the target area;

[0087] A first inversion unit is configured to perform AVO attribute inversion on the multi-azimuth seismic data of the target area to obtain AVO gradients of seismic data in each azimuth of the multi-azimuth seismic data;

[0088] A second determining unit is configured to determine the maximum AVO gradient difference corresponding to different directions in the multi-directional seismic data based on the AVO gradient of the seismic data in each direction;

[0089] A simulation unit is used to simulate bi-directional streamer acquisition on the established geological model of the target layer to obtain bi-directional seismic forward simulation data of the target layer;

[0090] The second inversion unit is used to perform AVO attribute inversion on the bi-directional seismic forward simulation data of the target layer to obtain the AVO gradient of the bi-directional seismic forward simulation data;

[0091] A third determining unit is configured to determine an AVO gradient difference corresponding to the two-orientation seismic forward modeling data based on the AVO gradient of the two-orientation seismic forward modeling data;

[0092] an estimating unit, configured to estimate a correction factor for the AVO gradient difference based on the AVO gradient difference corresponding to the two-orientation seismic forward modeling data and the formation dip;

[0093] The correction unit is used to correct the maximum AVO gradient difference based on the correction factor to obtain a corrected AVO gradient difference, so as to predict the fracture development of the target layer based on the corrected AVO gradient difference.

[0094] The working process, working details and technical effects of the pre-stack crack prediction device provided in the second aspect of this embodiment can be found in the first aspect of the embodiment and will not be described in detail here.

[0095] like Figure 6 As shown, the third aspect of an embodiment of the present application provides another device for predicting pre-stack cracks, comprising a memory, a processor, and a transceiver that are communicatively connected in sequence, wherein the memory is used to store computer programs, the transceiver is used to send and receive messages, and the processor is used to read the computer program and execute the method for predicting pre-stack cracks as described in the first aspect of the embodiment.

[0096] For example, the memory may include, but is not limited to, random access memory (RAM), read-only memory (ROM), flash memory, first-in-first-out memory (FIFO) and / or first-in-last-out memory (FILO), etc.; the processor may be but is not limited to a microprocessor of the STM32F105 series, an ARM (Advanced RISC Machines), an X86 or other architecture processor, or a processor with an integrated NPU (neural-network processing units); the transceiver may be, but is not limited to, a WiFi (Wireless Fidelity) wireless transceiver, a Bluetooth wireless transceiver, a General Packet Radio Service (GPRS) wireless transceiver, a ZigBee protocol (a low-power local area network protocol based on the IEEE802.15.4 standard, ZigBee) wireless transceiver, a 3G transceiver, a 4G transceiver and / or a 5G transceiver, etc.

[0097] A fourth aspect of this embodiment provides a computer-readable storage medium storing instructions for the method for predicting prestack cracks described in the first aspect of the embodiment. Specifically, the computer-readable storage medium stores instructions that, when executed on a computer, execute the method for predicting prestack cracks described in the first aspect. The computer-readable storage medium refers to a data storage medium and may include, but is not limited to, a floppy disk, an optical disk, a hard disk, a flash memory, a USB flash drive, and / or a memory stick. The computer may be a general-purpose computer, a dedicated computer, a computer network, or other programmable device.

[0098] A fifth aspect of this embodiment provides a computer program product comprising instructions, which, when executed on a computer, causes the computer to execute the method for predicting pre-stack cracks as described in the first aspect of the embodiment, wherein the computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device.

[0099] It should be understood that certain details are provided in the following description to facilitate a thorough understanding of the example embodiments. However, one of ordinary skill in the art will appreciate that the example embodiments can be practiced without these specific details. For example, a system may be shown in block diagrams to avoid obscuring the example with unnecessary detail. In other instances, well-known processes, structures, and techniques may be shown without unnecessary detail to avoid obscuring the example embodiments.

[0100] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention shall be included in the scope of protection of the present invention.

Claims

1. A method for predicting prestack fractures, characterized in that: include: Determining the stratigraphic inclination of the target layer based on stratigraphic position information of the target layer in the target area; Performing AVO attribute inversion on the multi-azimuth seismic data of the target area to obtain AVO gradients of seismic data in each azimuth of the multi-azimuth seismic data; Based on the AVO gradients of the seismic data in each orientation, determining the maximum AVO gradient differences corresponding to different orientations in the multi-azimuth seismic data; Perform bi-directional streamer acquisition simulation on the established geological model of the target layer to obtain bi-directional seismic forward simulation data of the target layer; Perform AVO attribute inversion on the bi-directional seismic forward simulation data of the target layer to obtain the AVO gradient of the bi-directional seismic forward simulation data; Based on the AVO gradient of the two-orientation seismic forward modeling data, determining the AVO gradient difference corresponding to the two-orientation seismic forward modeling data; estimating a correction factor for the AVO gradient difference based on the AVO gradient difference corresponding to the two-orientation seismic forward modeling data and the formation dip; The maximum AVO gradient difference is corrected based on the correction factor to obtain a corrected AVO gradient difference, so as to predict the fracture development of the target layer based on the corrected AVO gradient difference.

2. The method for predicting pre-stack cracks according to claim 1, wherein: The determining of the stratum dip angle of the target layer based on the stratum position information of the target layer in the target area includes: compiling a structural map of the target layer based on the stratigraphic position information of the target layer; The formation dip of the target layer is calculated based on the structure of the target layer.

3. The method for predicting pre-stack cracks according to claim 2, wherein: The step of compiling a structural map of the target layer based on the stratigraphic position information of the target layer includes: If the stratigraphic position information of the target layer is stratigraphic position information of a depth domain layer, compiling a structural map of the target layer based on the stratigraphic position information of the depth domain layer; If the stratigraphic position information of the target layer is the stratigraphic position information of the time domain layer, the stratigraphic position information of the time domain layer is converted into the stratigraphic position information of the depth domain layer, and then a structural map of the target layer is compiled based on the stratigraphic position information of the depth domain layer obtained by the conversion.

4. The method for predicting pre-stack cracks according to claim 1, wherein: Before performing a two-directional streamer acquisition simulation on the established geological model of the target layer, the method further includes: A geological model of the target layer is established based on the horizon position, fault information and rock physical parameters of the target layer.

5. The method for predicting pre-stack cracks according to claim 1, wherein: Before correcting the maximum AVO gradient difference based on the correction factor, the method further includes: Determining whether the maximum AVO gradient difference and the formation dip satisfy a predefined positive correlation; Correcting the maximum AVO gradient difference based on the correction factor includes: If the maximum AVO gradient difference and the formation dip satisfy a predefined positive correlation, the maximum AVO gradient difference is corrected based on the correction factor.

6. The method for predicting pre-stack cracks according to claim 1, characterized in that: The correction factor for the AVO gradient difference is a=D m12 / H Dip , where D m12 It represents the AVO gradient difference corresponding to the two-orientation seismic forward modeling data, H Dip Indicates the dip angle of the formation.

7. The method for predicting pre-stack cracks according to claim 6, characterized in that: The corrected AVO gradient difference is D = D n / (a×H Dip ), where D n represents the maximum AVO gradient difference.

8. A device for predicting pre-stack cracks, characterized in that: include: A first determining unit is configured to determine a stratum dip angle of a target layer based on stratum position information of the target layer in the target area; A first inversion unit is configured to perform AVO attribute inversion on the multi-azimuth seismic data of the target area to obtain AVO gradients of seismic data in each azimuth of the multi-azimuth seismic data; A second determining unit is configured to determine the maximum AVO gradient difference corresponding to different directions in the multi-directional seismic data based on the AVO gradient of the seismic data in each direction; A simulation unit is used to simulate bi-directional streamer acquisition on the established geological model of the target layer to obtain bi-directional seismic forward simulation data of the target layer; The second inversion unit is used to perform AVO attribute inversion on the bi-directional seismic forward simulation data of the target layer to obtain the AVO gradient of the bi-directional seismic forward simulation data; A third determining unit is configured to determine an AVO gradient difference corresponding to the two-orientation seismic forward modeling data based on the AVO gradient of the two-orientation seismic forward modeling data; an estimating unit, configured to estimate a correction factor for the AVO gradient difference based on the AVO gradient difference corresponding to the two-orientation seismic forward modeling data and the formation dip; The correction unit is used to correct the maximum AVO gradient difference based on the correction factor to obtain a corrected AVO gradient difference, so as to predict the fracture development of the target layer based on the corrected AVO gradient difference.

9. A device for predicting pre-stack cracks, characterized in that: The method comprises a memory, a processor and a transceiver which are communicatively connected in sequence, wherein the memory is used to store a computer program, the transceiver is used to send and receive messages, and the processor is used to read the computer program and execute the method for predicting prestack cracks according to any one of claims 1 to 7.

10. A computer program product comprising a computer program or instructions, characterized in that When the computer program or the instruction is executed by a computer, the method for predicting pre-stack cracks according to any one of claims 1 to 7 is implemented.

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