Seismic waveform envelope smoothing method, impedance model reconstruction method and equipment

Abstract

The present invention discloses a seismic waveform envelope smoothing method, an impedance model reconstruction method and equipment, including: first obtaining post-stack seismic data with missing low-frequency information; determining the strong reflection thick layer of the post-stack seismic data; for each seismic trace in the post-stack seismic data, using the travel time information of the strong reflection thick layer of each trace to obtain the corresponding waveform envelope smoothing window; using the waveform envelope smoothing window to smooth the waveform envelope of the seismic trace to obtain a smooth waveform envelope. The present invention uses the travel time difference of a specific layer to adaptively select a waveform envelope smoothing window for each seismic trace, effectively improving the matching degree between the smoothing window size and the impedance model based on the waveform envelope inversion of each seismic trace, reducing the calculation cost of measuring the smoothing window size, and improving the smoothing processing efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of seismic impedance inversion, and in particular to a seismic waveform envelope smoothing method, an impedance model reconstruction method and equipment. Background Art

[0002] The seismic full waveform inversion method is an important way to obtain underground model parameters. This method obtains the inversion result by solving the minimum difference between the observed data and the simulated data. It requires that the seismic data contain low-frequency components to ensure the reconstruction of the large-scale components of the model.

[0003] However, there is a problem of missing low-frequency information in actual seismic data. In order to obtain low-frequency information, the existing technology constructs low-frequency information by converting the original seismic data into the Laplace domain, calculating the amplitude energy, wave field intensity and waveform envelope, etc. The above existing methods are only applicable to models with weak reflection layers as the main body. For models with strong reflections and thick formations, such as salt dome models, the low-frequency information obtained by the above method cannot meet the requirements, because the reconstruction of strong reflection thick layers requires very low-frequency information. One way to obtain very low-frequency information is to smooth the seismic waveform envelope. The existing technology selects the smooth window by trial and error according to the data situation. There are problems such as long time consumption for calculating different window sizes and lack of accuracy of the selected window size, which in turn affects the accuracy of the inversion results.

[0004] Therefore, it is urgent to invent a seismic waveform envelope smoothing method that can adaptively select a smooth window to solve the problems of low smooth window matching and low window selection efficiency in the prior art for smoothing of strong reflection thick layers. Summary of the invention

[0005] In view of this, an embodiment of the present invention provides a seismic waveform envelope smoothing method, an impedance model reconstruction method and a device, which at least partially solve the problems existing in the prior art.

[0006] Other features and advantages of the present invention will become apparent from the following detailed description, or may be learned in part by practice of the present invention.

[0007] In order to achieve the above objectives, the embodiments of the present invention provide the following technical solutions:

[0008] According to a first aspect of an embodiment of the present invention, a method for smoothing a seismic data waveform envelope is provided, the method comprising:

[0009] Acquire post-stack seismic data that lack low-frequency information;

[0010] Determine a strong reflection thick layer of the post-stack seismic data;

[0011] For each seismic trace in the post-stack seismic data, according to the travel time information of the strong reflection thick layer corresponding to the seismic trace, a waveform envelope smooth window corresponding to the seismic trace is obtained;

[0012] The waveform envelope of the seismic trace is smoothed using the waveform envelope smoothing window to obtain a smooth waveform envelope.

[0013] Further, according to the travel time information of the strong reflection thick layer corresponding to the seismic trace, the waveform envelope smooth window corresponding to the seismic trace is obtained, including:

[0014] According to the top interface travel time information and the bottom interface travel time information of the strong reflection thick layer corresponding to the seismic trace, the travel time difference corresponding to the strong reflection thick layer of the seismic trace is obtained;

[0015] The travel time difference is used to obtain a waveform envelope smooth window corresponding to the seismic trace.

[0016] Further, the waveform envelope smooth window corresponding to the seismic trace is obtained by using the travel time difference, including:

[0017] The travel time difference is divided by the data sampling interval of the seismic trace to obtain a smoothing factor corresponding to the seismic trace;

[0018] The smoothing factor is used to determine the size of the waveform envelope smoothing window corresponding to the seismic trace.

[0019] Furthermore, the smoothing process uses a Gaussian smoothing function.

[0020] Furthermore, the strong reflection thick layer of the seismic trace is a salt dome layer.

[0021] According to a second aspect of an embodiment of the present invention, a large-scale component impedance model reconstruction method is provided, the method comprising:

[0022] For the impedance model, construct the objective function;

[0023] Using a seismic data waveform envelope smoothing method as described in any one of the above items, a waveform envelope smoothing window and a smooth waveform envelope are obtained;

[0024] According to the smooth waveform envelopes corresponding to the forward wave field and the return wave field, the gradient of the objective function to the impedance model parameters is calculated;

[0025] The impedance model is iteratively updated based on the gradient and the impedance model update step size to obtain an impedance model containing large-scale components.

[0026] Furthermore, the method further comprises:

[0027] The waveform envelope smoothing window is used to determine the impedance model update step size, and the impedance model update step size is proportional to the waveform envelope smoothing window size.

[0028] According to a third aspect of an embodiment of the present invention, a device is provided, the device comprising: a processor and a memory;

[0029] The memory is used to store one or more program instructions;

[0030] The processor is used to run one or more program instructions to execute the steps of a seismic data waveform envelope smoothing method as described in any of the above items, or to execute the steps of a large-scale component impedance model reconstruction method as described in any of the above items.

[0031] According to a fourth aspect of an embodiment of the present invention, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the steps of a seismic data waveform envelope smoothing method as described in any one of the above items are implemented, or the steps of a large-scale component impedance model reconstruction method as described in any one of the above items are implemented.

[0032] According to a fifth aspect of an embodiment of the present invention, a computer program product is provided, the computer program product comprising a computer program stored on a non-transitory computer-readable storage medium, the computer program comprising program instructions, which, when executed by a computer, enable the computer to implement the steps of a seismic data waveform envelope smoothing method as described in any of the above items, or to execute the steps of a large-scale component impedance model reconstruction method as described in any of the above items.

[0033] The embodiments of the present invention have the following advantages:

[0034] The seismic waveform envelope smoothing method and the large-scale component impedance model reconstruction method proposed in the embodiments of the present invention utilize the travel time difference of a specific layer to adaptively select a suitable waveform envelope smoothing window for each seismic trace, thereby effectively improving the matching degree between the smoothing window size and the seismic trace, thereby improving the calculation accuracy of the impedance model large-scale component reconstruction, and effectively reducing the calculation cost of the prior art for measuring the smoothing window size, thereby effectively improving the calculation efficiency of the impedance model large-scale component reconstruction. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the implementation methods of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for the implementation methods or the description of the prior art. Obviously, the drawings in the following description are only exemplary, and for ordinary technicians in this field, other implementation drawings can be derived from the provided drawings without creative work.

[0036] Figure 1 A schematic diagram of a flow chart of a seismic data waveform envelope smoothing processing method provided by an embodiment of the present invention;

[0037] Figure 2 A schematic flow chart of a large-scale component impedance model reconstruction method provided by an embodiment of the present invention;

[0038] Figure 3 A schematic diagram showing the effect of the travel time of the top and bottom interfaces of a seismic section and the size of the smooth window of the waveform envelope provided by an embodiment of the present invention;

[0039] Figure 4 A schematic diagram for comparing impedance waveform inversion provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0040] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0041] In addition, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover non-exclusive inclusions. For example, a process, method, system, product, or apparatus that includes a series of steps or elements is not necessarily limited to those steps or elements explicitly listed, but may include other steps or elements not explicitly listed or inherent to such process, method, product, or apparatus.

[0042] The embodiment of the invention discloses a method for smoothing the waveform envelope of seismic data. Figure 1 The figure shows a flow chart of a method for smoothing the waveform envelope of seismic data according to an embodiment of the present invention.

[0043] refer to Figure 1 , the seismic data waveform envelope smoothing processing method specifically includes:

[0044] First, post-stack seismic data lacking low-frequency information is obtained. The post-stack seismic data is a two-dimensional seismic profile or a three-dimensional seismic data volume.

[0045] Then, a strong reflection thick layer in the post-stack seismic data is determined, and the strong reflection thick layer may be a salt dome layer.

[0046] For each seismic trace in the post-stack seismic data, the waveform envelope smooth window corresponding to the seismic trace is obtained according to the travel time information of the strong reflection thick layer corresponding to each seismic trace, which specifically includes:

[0047] According to the travel time information of the top interface layer and the bottom interface layer of the strong reflection thick layer corresponding to the seismic trace, the travel time difference corresponding to the seismic trace is obtained. Figure 3 (a) shows the travel time of the top and bottom interfaces of the salt dome layer in the seismic profile. Figure 3 The dashed line in (a) corresponds to the travel time of the top interface, the dotted line corresponds to the travel time of the bottom interface, and the horizontal axis x is the seismic traces arranged in sequence according to the plane position.

[0048] The travel time difference is divided by the data sampling interval of the seismic trace to obtain the smoothing factor corresponding to the seismic trace.

[0049] Using the smoothing factor, the size of the waveform envelope smoothing window corresponding to the seismic trace is determined, and the waveform envelope smoothing window corresponding to the seismic trace is obtained. Figure 3 The relationship between the waveform envelope smooth window and the top and bottom interface travel time information is shown. Figure 3 The vertical axis of (b) is the size of the waveform envelope smoothing window.

[0050] The waveform envelope of each seismic trace is smoothed using the waveform envelope smoothing window corresponding to each seismic trace to obtain a smooth waveform envelope. The above smoothing is achieved through a Gaussian smoothing function.

[0051] A smoothing processing method for adaptively selecting a waveform envelope smoothing window is proposed in an embodiment of the present invention. By utilizing the travel time difference of a specific layer, a suitable waveform envelope smoothing window is adaptively selected for each seismic trace, thereby effectively improving the matching degree between the smoothing window size and the seismic trace, and effectively reducing the computational cost of calculating the smoothing window size in the prior art, thereby improving the smoothing processing efficiency.

[0052] The embodiment of the present invention also discloses a large-scale component impedance model reconstruction method. Figure 2 The figure shows a flow chart of a large-scale component impedance model reconstruction method according to an embodiment of the present invention.

[0053] The inversion target of the embodiment of the present invention is to reconstruct the large-scale component of the salt dome impedance model from the linear initial model, and the inversion is based on the wave equation containing only impedance parameters.

[0054] refer to Figure 2 , the large-scale component impedance model reconstruction method specifically includes:

[0055] Firstly, for the impedance model, an objective function is constructed, which is defined as the L2 norm of the difference between the observed smooth waveform envelope and the simulated smooth waveform envelope, and is used to reconstruct the large-scale model components.

[0056] Impedance inversion is performed using the objective function.

[0057] In the waveform envelope smoothing process of impedance inversion, post-stack seismic data lacking low-frequency information is obtained. The post-stack seismic data is a two-dimensional seismic profile or a three-dimensional seismic data volume.

[0058] Then, a strong reflection thick layer in the post-stack seismic data is determined, and the strong reflection thick layer may be a salt dome layer.

[0059] For each seismic trace in the post-stack seismic data, the waveform envelope smooth window corresponding to the seismic trace is obtained according to the travel time information of the strong reflection thick layer corresponding to each seismic trace, which specifically includes:

[0060] According to the travel time information of the top interface layer and the travel time information of the bottom interface layer of the strong reflection thick layer corresponding to the seismic trace, the travel time difference corresponding to the seismic trace is obtained.

[0061] The travel time difference is divided by the data sampling interval of the seismic trace to obtain the smoothing factor corresponding to the seismic trace.

[0062] The smoothing factor is used to determine the size of the waveform envelope smoothing window corresponding to the seismic trace, and the waveform envelope smoothing window corresponding to the seismic trace is obtained.

[0063] The waveform envelope of each seismic trace is smoothed using the waveform envelope smoothing window corresponding to each seismic trace to obtain a smooth waveform envelope. The above smoothing is achieved through a Gaussian smoothing function.

[0064] Then, according to the smooth waveform envelope of the forward wave field and the return wave field or the corresponding wave field, the gradient of the objective function to the impedance model parameters is calculated.

[0065] The waveform envelope smoothing window is used to determine the impedance model update step size, and the impedance model update step size is proportional to the waveform envelope smoothing window size.

[0066] Finally, the impedance model is iteratively updated based on the gradient and the impedance model update step, and the inversion results are smoothed to obtain an impedance model containing large-scale components.

[0067] Figure 4 A schematic diagram showing the comparison of impedance inversion effects is shown, where: Figure 4 (a) is the true impedance profile, Figure 4 (b) is the impedance model result obtained by conventional inversion method. Figure 4 (c) an impedance inversion model obtained according to the large-scale component impedance model reconstruction method disclosed in an embodiment of the present invention, Figure 4 (d) is the impedance inversion result obtained by using the conventional inversion method with the model in (c) as the initial model.

[0068] A large-scale component impedance model reconstruction method proposed in an embodiment of the present invention utilizes the travel time difference of a specific layer to adaptively select a suitable waveform envelope smooth window for each seismic trace, thereby effectively improving the matching degree between the smooth window size and the seismic trace, thereby improving the calculation accuracy of the impedance model large-scale component reconstruction, and effectively reducing the calculation cost of the prior art for measuring the smooth window size, thereby effectively improving the calculation efficiency of the impedance model large-scale component reconstruction.

[0069] In addition, an embodiment of the present invention also provides a device, which includes: a processor and a memory; the memory is used to store one or more program instructions; the processor is used to run one or more program instructions to execute the steps of a seismic data waveform envelope smoothing method as described in any of the above items, or to execute the steps of a large-scale component impedance model reconstruction method as described in any of the above items.

[0070] In addition, an embodiment of the present invention also provides a computer-readable storage medium, which stores a computer program. When the computer program is executed by a processor, it implements the steps of a seismic data waveform envelope smoothing method as described in any of the above items, or is used to execute the steps of a large-scale component impedance model reconstruction method as described in any of the above items.

[0071] In addition, an embodiment of the present invention also provides a computer program product, which includes computer program instructions. When the computer program instructions are executed by a processor, they implement the steps of a seismic data waveform envelope smoothing method as described in any of the above items, or are used to execute the steps of a large-scale component impedance model reconstruction method as described in any of the above items.

[0072] In the embodiment of the present invention, the processor may be an integrated circuit chip with signal processing capability. The processor may be a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA), or other programmable logic devices, discrete gates or transistor logic devices, or discrete hardware components. The methods, steps, and logic block diagrams disclosed in the embodiments of the present invention may be implemented or executed. The general-purpose processor may be a microprocessor or the processor may be any conventional processor, etc. The steps of the method disclosed in the embodiment of the present invention may be directly embodied as being executed by a hardware decoding processor, or may be executed by a combination of hardware and software modules in a decoding processor. The software module may be located in a mature storage medium in the art such as a random access memory, a flash memory, a read-only memory, a programmable read-only memory, or an electrically erasable programmable memory, a register, etc. The processor reads the information in the storage medium and completes the steps of the above method in combination with its hardware. The storage medium may be a memory, for example, a volatile memory or a non-volatile memory, or may include both volatile and non-volatile memories. Among them, the non-volatile memory can be a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), or a flash memory. The volatile memory can be a random access memory (RAM), which is used as an external cache. By way of example but not limitation, many forms of RAM are available, such as static random access memory (SRAM), dynamic random access memory (DRAM), synchronous dynamic random access memory (SDRAM), double data rate synchronous dynamic random access memory (DDRSDRAM), enhanced synchronous dynamic random access memory (ESDRAM), synchronous link dynamic random access memory (SLDRAM) and direct memory bus random access memory (Direct Rambus RAM, DRRAM).The storage medium described in the embodiment of the present invention is intended to include but is not limited to these and any other suitable types of memory. Those skilled in the art should be aware that in one or more of the above examples, the functions described in the present invention can be implemented by a combination of hardware and software. When the software is applied, the corresponding function can be stored in a computer-readable medium or transmitted as one or more instructions or codes on a computer-readable medium. Computer-readable media include computer storage media and communication media, wherein the communication medium includes any medium that is convenient for transmitting a computer program from one place to another. The storage medium can be any available medium that a general or special-purpose computer can access. Although the present invention has been described in detail above with general descriptions and specific embodiments, it is obvious to those skilled in the art that some modifications or improvements can be made to it on the basis of the present invention. Therefore, these modifications or improvements made on the basis of not departing from the spirit of the present invention all belong to the scope of protection claimed in the present invention.

Claims

1. A method for smoothing the waveform envelope of seismic data, characterized in that: The method comprises: Acquire post-stack seismic data that lack low-frequency information; Determine a strong reflection thick layer of the post-stack seismic data; For each seismic trace in the post-stack seismic data, according to the travel time information of the strong reflection thick layer corresponding to the seismic trace, a waveform envelope smooth window corresponding to the seismic trace is obtained, including: According to the top interface travel time information and the bottom interface travel time information of the strong reflection thick layer corresponding to the seismic trace, the travel time difference corresponding to the strong reflection thick layer of the seismic trace is obtained; Using the travel time difference, a waveform envelope smooth window corresponding to the seismic trace is obtained; The waveform envelope of the seismic trace is smoothed using the waveform envelope smoothing window to obtain a smooth waveform envelope.

2. A seismic data waveform envelope smoothing method as claimed in claim 1, characterized in that: Using the travel time difference, a waveform envelope smooth window corresponding to the seismic trace is obtained, including: The travel time difference is divided by the data sampling interval of the seismic trace to obtain a smoothing factor corresponding to the seismic trace; The smoothing factor is used to determine the size of the waveform envelope smoothing window corresponding to the seismic trace.

3. A seismic data waveform envelope smoothing method as claimed in claim 1, characterized in that: The smoothing process uses a Gaussian smoothing function.

4. A seismic data waveform envelope smoothing method as claimed in claim 1, characterized in that: The strong reflection thick layer of the seismic trace is a salt dome layer.

5. A large-scale component impedance model reconstruction method, characterized in that: The method comprises: For the impedance model, an objective function is constructed, and the objective function is defined as the L2 norm of the difference between the observed smooth waveform envelope and the simulated smooth waveform envelope; Using a seismic data waveform envelope smoothing processing method as claimed in any one of claims 1 to 4, a waveform envelope smoothing window and a smooth waveform envelope are obtained; According to the smooth waveform envelopes corresponding to the forward wave field and the return wave field, the gradient of the objective function to the impedance model parameters is calculated; The impedance model is iteratively updated based on the gradient and the impedance model update step size to obtain an impedance model containing large-scale components.

6. A large-scale component impedance model reconstruction method according to claim 5, the method further comprising: The waveform envelope smoothing window is used to determine the impedance model update step size, and the impedance model update step size is proportional to the waveform envelope smoothing window size.

7. A device, characterized in that: The device comprises: a processor and a memory; The memory is used to store one or more program instructions; The processor is used to run one or more program instructions to execute the steps of a seismic data waveform envelope smoothing method as described in any one of claims 1 to 4, or to execute the steps of a large-scale component impedance model reconstruction method as described in any one of claims 5 to 6.

8. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, which, when executed by a processor, implements the steps of a seismic data waveform envelope smoothing method as described in any one of claims 1 to 4, or executes the steps of a large-scale component impedance model reconstruction method as described in any one of claims 5 to 6.

9. A computer program product, characterized in that The computer program product includes computer program instructions, which, when executed by a processor, implement the steps of a seismic data waveform envelope smoothing method as described in any one of claims 1 to 4, or execute the steps of a large-scale component impedance model reconstruction method as described in any one of claims 5 to 6.

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