Tomography method and device based on geological outcrop near-surface constraint

Abstract

The invention provides a geological outcrop near-surface constraint-based chromatography method and device. The geological outcrop near-surface constraint-based chromatography method comprises the steps of generating a plurality of two-dimensional stratigraphic sections according to field outcrop data of a target work area; wherein the two-dimensional stratigraphic section at least comprises interval velocity data of each stratum; generating three-dimensional body data of the target work area according to the plurality of two-dimensional stratigraphic profiles; performing near-surface travel time tomography inversion on an initial surface velocity model of the target work area according to the three-dimensional body data and a pre-generated tomography matrix of the target work area to generate a near-surface velocity model of the target work area; and performing chromatography operation on the target work area according to the near-surface velocity model. On the basis of field geological outcrop survey data, survey data are converted into speed data to be used for restraining the updating direction and updating amount of near-surface tomography speed modeling, and then the geological rationality and accuracy of a near-surface speed model are improved.

Description

Technical Field

[0001] This application belongs to the technical field of seismic exploration and development in oil and gas fields, especially in the field of seismic imaging technology in oil and gas field exploration and development. Specifically, it relates to a tomography method and device based on near-surface constraint of geological outcrops. Background Art

[0002] As the seismic exploration area gradually shifts from the eastern plains of China to complex seismic geological condition areas such as the Gobi, desert, and piedmont zones in the southwest, the requirements for seismic exploration processing technology are getting higher and higher in this situation. Especially now that seismic exploration technology is gradually moving towards high-precision depth-domain processing, there is an urgent need to obtain high-precision and high-resolution imaging profiles of underground media. Research by industry scholars over the years has shown that the accuracy of the underground velocity model in the depth domain is crucial for seismic imaging. And near-surface velocity modeling, as the first and most important step in depth-domain modeling, the accuracy of its velocity is related to the success or failure of seismic exploration. There is an urgent need for a method in the existing technology that can accurately determine the surface velocity model, and then obtain accurate tomography results for the target work area. Summary of the Invention

[0003] This invention belongs to the field of seismic imaging technology in oil and gas field exploration and development. An object of this invention is to accurately obtain the depth-domain velocity model of the shallow surface layer of underground media in complex seismic geological condition areas such as the Gobi, desert, and piedmont zones in the southwest, so as to improve the success rate of seismic exploration.

[0004] Another object of this invention is to provide a tomography device based on near-surface constraint of geological outcrops. Still another object of this invention is to provide an electronic device, which includes a memory and a processor. The memory stores a computer program, and when the processor executes the computer program, it implements the steps of the above-mentioned tomography method based on near-surface constraint of geological outcrops. Still another object of this invention is to provide a readable medium, on which a computer program is stored, and when the computer program is executed by the processor, it implements the steps of the above-mentioned tomography method based on near-surface constraint of geological outcrops.

[0005] To solve the technical problems in the background art of this application, this invention provides the following technical solutions:

[0006] In the first aspect, this invention provides a tomography method based on near-surface constraint of geological outcrops, including:

[0007] Generating a plurality of two-dimensional stratigraphic profiles according to the field outcrop data of the target work area; wherein, the two-dimensional stratigraphic profile at least includes the layer velocity data of each stratum;

[0008] Generating three-dimensional volume data of the target work area according to the plurality of two-dimensional stratigraphic profiles;

[0009] Performing near-surface travel-time tomography inversion on the initial surface velocity model of the target work area according to the three-dimensional volume data and the pre-generated tomography matrix of the target work area to generate the near-surface velocity model of the target work area;

[0010] Performing tomography operation on the target work area according to the near-surface velocity model.

[0011] In some embodiments of the present invention, the near-surface travel-time tomography inversion is in a multi-round iterative manner. The performing near-surface travel-time tomography inversion on the initial surface velocity model of the target work area according to the three-dimensional volume data and the pre-generated tomography matrix of the target work area includes:

[0012] Performing ray tracing on the surface velocity model of the previous round of surface travel-time tomography inversion to generate the tomography matrix of the current round of surface travel-time tomography inversion;

[0013] Determining the update amount of the surface velocity model of the next round of surface travel-time tomography inversion according to the tomography matrix of the current round of surface travel-time tomography inversion;

[0014] Performing the next round of surface travel-time tomography inversion on the surface velocity model of the current round according to the update amount and the three-dimensional volume data.

[0015] In some embodiments of the present invention, determining the update amount of the surface velocity model of the next round of surface travel-time tomography inversion according to the tomography matrix of the current round of surface travel-time tomography inversion includes:

[0016] Constraining the solution process of the tomography matrix of the current round of surface travel-time tomography inversion according to the three-dimensional volume data to generate the solution of the tomography matrix of the current round of surface travel-time tomography inversion;

[0017] Determining the update amount according to the solution.

[0018] In some embodiments of the present invention, a tomography method based on near-surface constraint of geological outcrops further includes:

[0019] Segmenting the near-surface velocity model to generate a plurality of two-dimensional slices;

[0020] Checking the accuracy of the near-surface velocity model according to the difference between the plurality of two-dimensional stratigraphic profiles and the corresponding plurality of two-dimensional slices.

[0021] In some embodiments of the present invention, before generating the three-dimensional volume data of the target work area according to the plurality of two-dimensional stratigraphic profiles, it further includes:

[0022] Modify the multiple two-dimensional stratigraphic profiles according to the lithology, fracture development trend, rock porosity, and rock particle size of the target work area.

[0023] In some embodiments of the present invention, generating three-dimensional volume data of the target work area based on the multiple two-dimensional stratigraphic profiles includes:

[0024] Performing interpolation extrapolation on the multiple two-dimensional stratigraphic profiles according to the work area coordinates of the target work area to generate the three-dimensional volume data.

[0025] In some embodiments of the present invention, slicing the near-surface velocity model to generate a plurality of two-dimensional slices includes:

[0026] Vertically slicing the near-surface velocity model along the survey line direction of the target work area to obtain the plurality of two-dimensional slices.

[0027] In a second aspect, the present invention provides a tomography device based on near-surface constraints of geological outcrops, the device includes:

[0028] A two-dimensional stratigraphic profile generation module, configured to generate a plurality of two-dimensional stratigraphic profiles according to the field outcrop data of the target work area; wherein, the two-dimensional stratigraphic profile at least includes the layer velocity data of each stratum;

[0029] A three-dimensional volume data generation module, configured to generate three-dimensional volume data of the target work area based on the multiple two-dimensional stratigraphic profiles;

[0030] A near-surface velocity model generation module, configured to perform near-surface travel-time tomography inversion on the initial surface velocity model of the target work area according to the three-dimensional volume data and the pre-generated tomography matrix of the target work area to generate the near-surface velocity model of the target work area;

[0031] A work area tomography module, configured to perform tomography operation on the target work area according to the near-surface velocity model.

[0032] In some embodiments of the present invention, the near-surface travel-time tomography inversion is in a multi-round iterative manner, and the near-surface velocity model generation module includes:

[0033] A tomography matrix generation unit for the current round, configured to perform ray tracing on the surface velocity model of the previous round of surface travel-time tomography inversion to generate the tomography matrix of the current round of surface travel-time tomography inversion;

[0034] A next-round update amount determination unit, configured to determine the update amount of the surface velocity model of the next round of surface travel-time tomography inversion according to the tomography matrix of the current round of surface travel-time tomography inversion;

[0035] The next-round tomography inversion unit is configured to perform the next-round surface traveltime tomography inversion on the current-round surface velocity model according to the update amount and the three-dimensional volume data.

[0036] In some embodiments of the present invention, the next-round update amount determination unit includes:

[0037] A solution generation unit, configured to constrain the solution process of the tomography matrix for the current-round surface traveltime tomography inversion according to the three-dimensional volume data, so as to generate the solution of the tomography matrix for the current-round surface traveltime tomography inversion;

[0038] An update amount determination subunit, configured to determine the update amount according to the solution.

[0039] In some embodiments of the present invention, a tomography device based on near-surface constraint of geological outcrops further includes:

[0040] A two-dimensional slice acquisition module, configured to slice the near-surface velocity model to generate a plurality of two-dimensional slices;

[0041] A model accuracy inspection module, configured to inspect the accuracy of the near-surface velocity model according to the difference between the plurality of two-dimensional stratigraphic profiles and the corresponding plurality of two-dimensional slices.

[0042] In some embodiments of the present invention, a tomography device based on near-surface constraint of geological outcrops further includes:

[0043] A two-dimensional profile correction module, configured to correct the plurality of two-dimensional stratigraphic profiles according to the lithology, fracture development trend, rock porosity, and rock particle size of the target work area.

[0044] In some embodiments of the present invention, the three-dimensional volume data generation module includes:

[0045] A three-dimensional volume data generation unit, configured to perform difference extrapolation on the plurality of two-dimensional stratigraphic profiles according to the work area coordinates of the target work area to generate the three-dimensional volume data.

[0046] In some embodiments of the present invention, the near two-dimensional slice acquisition module includes:

[0047] A two-dimensional slice acquisition unit, configured to vertically slice the near-surface velocity model along the survey line direction of the target work area to obtain the plurality of two-dimensional slices.

[0048] In a third aspect, the present invention provides a computer program product, including computer programs / instructions, which, when executed by a processor, implement the steps of a tomography method based on near-surface constraint of geological outcrops.

[0049] Fourth aspect, the present invention provides an electronic device, including a memory, a processor, and a computer program stored on the memory and executable on the processor. When the processor executes the program, it implements the steps of the tomography method based on near-surface constraints of geological outcrops.

[0050] Fifth aspect, the present invention provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, it implements the steps of the tomography method based on near-surface constraints of geological outcrops.

[0051] As can be seen from the above description, the embodiments of the present invention provide a tomography method and device based on near-surface constraints of geological outcrops. The corresponding tomography method based on near-surface constraints of geological outcrops includes: First, generate a plurality of two-dimensional stratigraphic profiles according to the field outcrop data of the target work area; wherein, the two-dimensional stratigraphic profile data at least includes the layer velocity data of each stratum; Then, generate three-dimensional volume data of the target work area according to the plurality of two-dimensional stratigraphic profiles; perform near-surface traveltime tomography inversion on the initial surface velocity model of the target work area according to the three-dimensional volume data and the pre-generated tomography matrix of the target work area to generate a near-surface velocity model of the target work area; Finally, perform tomography operation on the target work area according to the near-surface velocity model.

[0052] The corresponding tomography device based on near-surface constraints of geological outcrops includes: a two-dimensional stratigraphic profile generation module, configured to generate a plurality of two-dimensional stratigraphic profiles according to the field outcrop data of the target work area; wherein, the two-dimensional stratigraphic profile data at least includes the layer velocity data of each stratum; a three-dimensional volume data generation module, configured to generate three-dimensional volume data of the target work area according to the plurality of two-dimensional stratigraphic profiles; a near-surface velocity model generation module, configured to perform near-surface traveltime tomography inversion on the initial surface velocity model of the target work area according to the three-dimensional volume data and the pre-generated tomography matrix of the target work area to generate a near-surface velocity model of the target work area; a work area tomography module, configured to perform tomography operation on the target work area according to the near-surface velocity model.

[0053] The tomography method and device based on near-surface constraints of geological outcrops provided by the embodiments of the present invention, on the basis of field geological outcrop survey data, convert the survey data into velocity data to constrain the update direction and update amount of near-surface tomography velocity modeling, thereby improving the geological rationality and accuracy of the near-surface velocity model. Description of the Drawings

[0054] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained according to these drawings.

[0055] Figure 1 Schematic diagram of a process of a tomography method based on near-surface constraint of geological outcrops in an embodiment of the present invention;

[0056] Figure 2 Schematic diagram of the process of step 300 of a tomography method based on near-surface constraint of geological outcrops in an embodiment of the present invention;

[0057] Figure 3 Schematic diagram of the process of step 302 of a tomography method based on near-surface constraint of geological outcrops in an embodiment of the present invention;

[0058] Figure 4 Another schematic diagram of the process of a tomography method based on near-surface constraint of geological outcrops in an embodiment of the present invention;

[0059] Figure 5 Third schematic diagram of the process of a tomography method based on near-surface constraint of geological outcrops in an embodiment of the present invention;

[0060] Figure 6 Schematic diagram of the process of step 200 of a tomography method based on near-surface constraint of geological outcrops in an embodiment of the present invention;

[0061] Figure 7 Schematic diagram of the process of step 500 of a tomography method based on near-surface constraint of geological outcrops in an embodiment of the present invention;

[0062] Figure 8 Schematic diagram of the process of a tomography method based on near-surface constraint of geological outcrops in the specific implementation manner of the present invention;

[0063] Figure 9 Schematic of a field geological outcrop in the specific implementation manner of the present invention Figure 1 (Silurian mudstone);

[0064] Figure 10 Schematic of a field geological outcrop in the specific implementation manner of the present invention Figure 2 (Ordovician sandstone);

[0065] Figure 11 Schematic of a field geological outcrop in the specific implementation manner of the present invention Figure 3 (Permian limestone);

[0066] Figure 12 Schematic of a field geological outcrop in the specific implementation manner of the present invention Figure 4 (Triassic limestone);

[0067] Figure 13 Planar schematic diagram of a field geological outcrop in the specific implementation manner of the present invention;

[0068] Figure 14 It is the schematic diagram of the field reconnaissance plan in the specific implementation manner of the present invention;

[0069] Figure 15 It is the schematic diagram of the interpolated three-dimensional model of the field reconnaissance in the specific implementation manner of the present invention;

[0070] Figure 16 It is the block diagram of a tomography device based on near-surface constraints of geological outcrops in the embodiment of the present invention;

[0071] Figure 17 It is the schematic diagram of the structure of an electronic device in the embodiment of the present invention. Specific implementation manner

[0072] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some but not all of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without making creative efforts fall within the scope of protection of the present invention.

[0073] Those skilled in the art should understand that the embodiments of the present invention can be provided as a method, a system, or a computer program product. Therefore, the present invention can take the form of an all-hardware embodiment, an all-software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present invention can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0074] It should be noted that the terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned accompanying drawings are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products, or devices. Without conflict, the embodiments in this application and the features in the embodiments can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0075] In the technical solution of this application, the acquisition, storage, use, processing, etc. of data all comply with the relevant regulations of laws and regulations.

[0076] Embodiment 1:

[0077] An embodiment of the present invention provides a specific implementation manner of a tomography method based on near-surface constraints of geological outcrops. Refer to Figure 1 , and specifically includes the following contents:

[0078] Step 100: Generate a plurality of two-dimensional stratigraphic profiles according to the field outcrop data of the target work area; wherein, the two-dimensional stratigraphic profile data at least includes the layer velocity data of each stratum;

[0079] Step 200: Generate three-dimensional volume data of the target work area according to the plurality of two-dimensional stratigraphic profiles;

[0080] Step 300: Perform near-surface traveltime tomography inversion on the initial surface velocity model of the target work area according to the three-dimensional volume data and the pre-generated tomography matrix of the target work area to generate the near-surface velocity model of the target work area;

[0081] Step 400: Perform tomography operation on the target work area according to the near-surface velocity model.

[0082] As can be seen from the above description, an embodiment of the present invention provides a tomography method based on near-surface constraints of geological outcrops, including: First, generate a plurality of two-dimensional stratigraphic profiles according to the field outcrop data of the target work area; wherein, the two-dimensional stratigraphic profile data at least includes the layer velocity data of each stratum; Then, generate three-dimensional volume data of the target work area according to the plurality of two-dimensional stratigraphic profiles; Perform near-surface traveltime tomography inversion on the initial surface velocity model of the target work area according to the three-dimensional volume data and the pre-generated tomography matrix of the target work area to generate the near-surface velocity model of the target work area; Finally, perform tomography operation on the target work area according to the near-surface velocity model.

[0083] As can be seen from the above description, an embodiment of the present invention provides a tomography method based on near-surface constraints of geological outcrops, including: First, generate a plurality of two-dimensional stratigraphic profiles according to the field outcrop data of the target work area; wherein, the two-dimensional stratigraphic profile data at least includes the layer velocity data of each stratum; Then, generate three-dimensional volume data of the target work area according to the plurality of two-dimensional stratigraphic profiles; Perform near-surface traveltime tomography inversion on the initial surface velocity model of the target work area according to the three-dimensional volume data and the pre-generated tomography matrix of the target work area to generate the near-surface velocity model of the target work area; Finally, perform tomography operation on the target work area according to the near-surface velocity model.

[0084] The present invention proposes a near-surface constraint tomography method system based on geological outcrops for the shallow surface layer in exploration areas with complex seismic geological conditions such as the southwestern Gobi area, desert area, and piedmont zone. Using the present invention, a depth-domain velocity model of the shallow surface layer of the underground medium can be accurately obtained, improving the success rate of seismic exploration.

[0085] Embodiment Two:

[0086] Preferably, the outcrop data in step 100 refers to the geological feature data directly observed and recorded in field geological exploration, such as the thickness, lithology, and structural features of rock formations. Preferably, the outcrop data includes: rock physical information such as formation outcrop lithology characteristics, rock texture, porosity, formation distribution characteristics, and formation morphological range characteristics.

[0087] Regarding step 200, it can be understood that a two-dimensional formation profile refers to a cross-sectional view of the formation distribution drawn through the study and observation of underground formations in geology. Such a cross-sectional view is drawn after measuring and sampling at a specific location or area, showing information such as the stacking sequence, lithology, and thickness of the formations, and is presented in the vertical direction (depth or elevation). Two-dimensional formation profiles are mainly used for studying geological structures, rock associations, sedimentary environments, mineral resources, etc.

[0088] The drawn two-dimensional formation profile needs to be subjected to field geological surveys and sampling to collect geological data such as rock samples, borehole data, and formation measurements. Then, based on the collected data, geological software or drawing tools are used to organize and process these data to draw the formation cross-sectional view. Such a formation cross-sectional view is used to understand the distribution and properties of the formations, and further study issues such as geological history, geological evolution, and the distribution and development of geological resources.

[0089] Preferably, the two-dimensional formation profile in step 200 includes the formation combination situation, formation texture, and structural features of the target work area; in addition, the geological age of the formation is analyzed based on the reconnaissance results to determine the approximate velocity distribution range.

[0090] The near-surface velocity model in step 300 is a model used to describe the acoustic wave propagation velocity in underground media. It refers to the relationship between the acoustic wave propagation velocities of different underground media and depth in the near-surface area. The near-surface velocity model can be obtained through seismic exploration techniques and seismic data processing. When seismic waves propagate in underground media, they are affected by the underground media and undergo refraction, reflection, etc. By analyzing the propagation characteristics of these seismic waves, the velocity information of the underground media can be inferred.

[0091] The near-surface velocity model is usually presented in the form of a velocity-depth curve. It describes the change in the acoustic wave propagation velocity with depth in underground media, and this change can be used to infer the properties of underground media such as density and lithology. Preferably, the near-surface velocity model can be established in the following ways:

[0092] By sending artificially excited seismic waves (such as seismic sources) and recording the propagation of seismic waves underground, the velocity information of underground media can be obtained. Common seismic exploration methods include reflection seismic method, refraction seismic method, etc.

[0093] Calculate and infer the near-surface velocity model by analyzing underground samples obtained from drilling operations. These samples can include cores, soil samples, etc. Through laboratory tests and analyses, the velocity of underground media can be inferred.

[0094] A method for inferring the near-surface velocity model by monitoring seismic events and analyzing the propagation paths of seismic waves. Using waveform data of seismic events recorded by multiple seismic monitoring stations and combining mathematical models and calculation methods, the velocity information of underground media can be inversely calculated.

[0095] A method for establishing the near-surface velocity model by analyzing the propagation paths and velocity information of seismic waves on the ground. It uses the scattering and diffraction of seismic waves and the analysis method of seismic record data, and can obtain the velocity information of underground media in a non-invasive manner.

[0096] Regarding step 400, tomographic inversion is a technique for inversely calculating the properties of underground substances using seismic data and analyzing layer by layer to image its internal structure. Tomographic inversion can visually and clearly display the fine structure and local inhomogeneity inside the formation in the form of an image.

[0097] The methods for wave field numerical simulation in tomographic inversion are divided into two categories, namely wave equation numerical simulation and ray tracing numerical simulation. The wave equation contains rich wave field information, and the simulation results are relatively accurate, providing more evidence for studying the propagation mechanism of seismic waves and the interpretation of complex formations. However, this method is prone to generating interfering waves, has a slow calculation speed, requires a high-performance computer, and assumes that the surface is a horizontal plane, which does not conform to the actual field seismic exploration situation. Relatively speaking, the ray tracing method (this application exactly uses this method) has a clear concept, can intuitively reflect the geometric propagation path of seismic waves, has a fast calculation speed, and can flexibly handle the undulating surface situation. As an effective means for exploring the distribution of underground media and the propagation of seismic waves in the formation, it has been widely used in seismic forward problems, especially occupying an important position in fields such as tomography and prestack depth migration.

[0098] In some embodiments of the present invention, the near-surface travel time tomographic inversion is in a multi-round iterative manner. Next, referring to Figure 2 , step 300 includes:

[0099] Step 301: Perform ray tracing on the surface velocity model of the previous round of surface travel time tomographic inversion to generate the tomographic matrix of the current round of surface travel time tomographic inversion;

[0100] In this tomographic matrix, it contains the difference between the first arrival travel time obtained from the ray tracing forward calculation and the first arrival travel time collected in the work area, as well as the path information of the ray.

[0101] Step 302: Determine the update amount of the surface velocity model for the next round of surface travel-time tomographic inversion based on the tomographic matrix of the current round of surface travel-time tomographic inversion;

[0102] Based on Step 301, solve the tomographic matrix to complete the calculation of the update amount of the near-surface velocity model.

[0103] Step 303: Perform the next round of surface travel-time tomographic inversion on the surface velocity model of the current round according to the update amount and the three-dimensional volume data.

[0104] In Steps 301 to 303, first establish an initial velocity model as the result of the previous round, and then perform ray tracing on the velocity model of the previous round to establish a tomographic matrix. In this matrix, it includes the difference between the first arrival travel times obtained from the forward ray tracing calculation and the first arrival travel times collected in the work area, as well as the ray path information; then solve the tomographic matrix to complete the calculation of the update amount of the near-surface velocity model; and during the process of solving the tomographic matrix, use the three-dimensional geological structure-velocity model data of the work area that has been obtained to perform constraints on the velocity distribution and velocity detail description of the update amount of the near-surface velocity model.

[0105] In some embodiments of the present invention, refer to Figure 3 , Step 302 includes:

[0106] Step 3021: Constrain the solution process of the tomographic matrix of the current round of surface travel-time tomographic inversion according to the three-dimensional volume data to generate the solution of the tomographic matrix of the current round of surface travel-time tomographic inversion;

[0107] Preferably, the LSQR method or the SIRT method can be used to solve the tomographic matrix of the surface travel-time tomographic inversion of the round. Specifically:

[0108] The LSQR (Least Squares QR) method is an iterative method used to solve the linear equations of the least squares problem. By using the ideas of QR decomposition and orthogonal projection, an approximate solution is sought in each iteration step to minimize the norm of the residual vector.

[0109] The least squares problem refers to solving a linear equation system in the form of Ax = b, where A is an m×n matrix (m > n) and b is a column vector. When the equation system has no solution, we hope to find a vector x that minimizes ||Ax - b||^2. The LSQR method is designed to solve this problem.

[0110] The basic idea of the LSQR method is that in each iteration step, the residual vector b - Ax is projected onto the orthogonal complement of the column space of A, and then the QR decomposition is used to solve the least-squares solution of the projected residual vector. In this way, through multiple iterations, the solution of the least-squares problem is gradually approximated.

[0111] The LSQR method is applicable to solving linear equations of sparse matrices or large matrices, and is particularly widely used in inverse problems. Its advantage is that it can quickly converge to an approximate solution and can handle matrices with incomplete column spaces. The LSQR method can also be used to solve regularization problems by introducing regularization terms to control the smoothness and sparsity of the solution.

[0112] SIRT (Simultaneous Iterative Reconstruction Technique) is also an iterative method used to solve linear equations in tomographic reconstruction problems. It is a back-projection algorithm that approximates the solution of the linear equations through multiple iterations.

[0113] In tomographic reconstruction problems, it is desired to reconstruct the internal structure of an object from some measurement data (such as projection data). This process can be described as a linear equation system, where the unknowns are the internal parameters or pixel values of the object, and the measurement data are known. The SIRT method is used to solve such a linear equation system.

[0114] The basic idea of the SIRT method is to approximate the solution of the linear equation system through multiple iterations. In each iteration step, the SIRT method back-projects and corrects the projection data in space to gradually approximate the true solution. Specifically, the SIRT method updates the estimation of pixel values by distributing the projection data to the pixels in space and correcting according to the contribution degree of the pixels. Through multiple rounds of iteration, the accuracy of the reconstruction result can be gradually improved.

[0115] Step 3022: Determine the update amount according to the solution.

[0116] In some embodiments of the present invention, referring to Figure 4 , a tomographic method based on near-surface constraints of geological outcrops further includes:

[0117] Step 500: Segment the near-surface velocity model to generate multiple two-dimensional slices;

[0118] Step 600: Check the accuracy of the near-surface velocity model according to the difference between the multiple two-dimensional stratigraphic profiles and the corresponding multiple two-dimensional slices.

[0119] In steps 500 and 600, multiple two-dimensional slice data that are the same as the field reconnaissance location are obtained. The obtained two-dimensional slice data are compared with the two-dimensional stratigraphic profile in step 100, and the mean square error is calculated. If the mean square error is within the maximum allowable error range for the current near-surface velocity model modeling, the near-surface velocity model is output; if the error is large, return to the constraint steps of the near-surface model by the update amount in terms of velocity distribution and velocity detail description, increase the size of the constraint factor (generally twice the previous value), and perform velocity inversion again until the calculated mean square error is within the controllable range.

[0120] In some embodiments of the present invention, referring to Figure 5 , a tomography method based on near-surface constraints of geological outcrops, before step 200, further includes:

[0121] Step 190: Modify the multiple two-dimensional stratigraphic profiles according to the lithology, fracture development trend, rock porosity, and rock particle size of the target work area.

[0122] Specifically, according to the petrophysical information such as lithology characteristics obtained through field reconnaissance in step 100, such as lithology, fracture development trend, rock porosity, rock particle size, etc., and then perform constraints on the filling velocity range for each two-dimensional stratigraphic profile to obtain a two-dimensional stratigraphic profile of a geological model with higher accuracy.

[0123] Lithology refers to the composition and structural characteristics of rocks, which describe the mineral composition, particle composition, structural type, etc. of rocks. Lithology is the basis for classifying rock types and studying rock properties, and is of great significance for geological research, engineering design, etc.

[0124] Fracture orientation refers to the distribution direction of fractures in rocks. Fractures are breaks or gaps in rocks, which have important effects on the mechanical properties, permeability, etc. of rocks. By studying the fracture development trend, the tectonic stress state, fault activity, hydrogeological characteristics, etc. of rocks can be understood.

[0125] Rock porosity refers to the proportion of pore space in rocks. Porosity is an important parameter for describing the reservoir properties of rocks and has important effects on the permeability, reservoir capacity, etc. of rocks. Common rock pores include capillary pores, fissures, dissolution pores, etc.

[0126] Rock particle size refers to the size of rock particles. Rock particle size has important effects on the mechanical properties, permeability, etc. of rocks. By studying the rock particle size distribution, the particle composition, sedimentary environment, rock properties, etc. of rocks can be understood.

[0127] In some embodiments of the present invention, referring to Figure 6 , step 200 includes:

[0128] Step 201: Perform difference extrapolation on the multiple two-dimensional stratigraphic profiles according to the work area coordinates of the target work area to generate the three-dimensional volume data.

[0129] Based on multiple two-dimensional stratigraphic profiles, interpolation extrapolation is performed using the work area coordinate information to obtain the three-dimensional volume data of the entire work area. This data contains the geological structure information of the three-dimensional near-surface of this work area, and the velocity numerical distribution is also the same as the actual outcrop distribution in the work area.

[0130] In some embodiments of the present invention, referring to Figure 7 , step 500 includes:

[0131] Step 501: Vertically slice the near-surface velocity model along the survey line direction of the target work area to obtain the multiple two-dimensional slices.

[0132] A survey line refers to a measurement line on the ground during engineering construction or exploration operations to determine the underground conditions or geological structure within the work area. The work area survey line usually consists of a series of measurement points or markers for determining the location of underground facilities, the trend of geological structures, surface deformation and other information.

[0133] As can be seen from the above description, the embodiments of the present invention provide a tomography method based on near-surface constraints of geological outcrops, including: First, generate multiple two-dimensional stratigraphic profiles according to the field outcrop data of the target work area; wherein, the two-dimensional stratigraphic profile data at least includes the layer velocity data of each stratum; then, generate the three-dimensional volume data of the target work area according to the multiple two-dimensional stratigraphic profiles; perform near-surface travel-time tomography inversion on the initial surface velocity model of the target work area according to the three-dimensional volume data and the pre-generated tomography matrix of the target work area to generate the near-surface velocity model of the target work area; finally, perform tomography operation on the target work area according to the near-surface velocity model.

[0134] The present invention aims at the shallow surface layer of exploration areas with complex seismic geological conditions such as the southwestern Gobi area, desert area and piedmont zone. According to the field geological outcrop survey data, the near-surface geological conditions are inferred to constrain the near-surface tomography to improve the inversion accuracy.

[0135] Embodiment 3:

[0136] In a specific implementation manner, the present invention also provides a specific implementation manner of a tomography method based on near-surface constraints of geological outcrops, referring to Figure 8 , specifically including the following steps.

[0137] S1: Conduct a field reconnaissance according to the topographic characteristics of the work area.

[0138] See Figures 9 to 12 Based on the lithological characteristics of the outcrops of the underground strata in the field obtained from the reconnaissance, the rock textures, and the petrophysical information such as porosity, the stratigraphic distribution characteristics, and the morphological range characteristics of the strata, multiple two-dimensional images of the stratigraphic profiles are obtained. See Figure 13 The images contain the stratigraphic combination, stratigraphic texture, and structural characteristics of the work area. In addition, the geological age of the strata is analyzed based on the reconnaissance results to determine the approximate velocity distribution range.

[0139] S2: Generate multiple two-dimensional stratigraphic profiles based on the field outcrop data of the target work area.

[0140] According to the stratigraphic structure characteristics in the work area obtained in step S1, the two-dimensional images are converted into digital records and input into the computer system to obtain multiple two-dimensional data files. Each file contains the stratigraphic structure included in the corresponding reconnaissance results. In addition, according to the estimated age and velocity of each layer of strata in the first step, the velocity range is filled into each data file to obtain multiple two-dimensional plane data with specific velocity values.

[0141] In addition, based on the petrophysical information such as lithological characteristics obtained from the field reconnaissance, such as lithology, fracture development trend, rock porosity, and rock particle size, the velocity range filling of each two-dimensional plane data obtained in the second step is further constrained to obtain two-dimensional plane data of a geological model with higher precision. See Figure 14 .

[0142] S3: Based on multiple two-dimensional plane data, use the coordinate information of the work area for interpolation and extrapolation to obtain the three-dimensional volume data of the entire work area. See Figure 15 . This data contains the geological structure information of the three-dimensional near-surface of the work area, and the velocity numerical distribution is also the same as the field outcrop distribution of the actual work area.

[0143] In the ray-tracing-based near-surface travel-time tomography inversion technology, it is necessary to first establish an initial velocity model as the result of the previous round, and then perform ray tracing on the velocity model of the previous round to establish a tomography matrix. In this matrix, it includes the difference between the first arrival travel time obtained from the forward ray-tracing calculation and the first arrival travel time collected in the work area, as well as the ray path information; then solve the tomography matrix to complete the calculation of the update amount of the near-surface velocity model; in the present invention, in the matrix solution step, using the obtained three-dimensional geological structure-velocity model data of the work area, constraints are imposed on the velocity distribution and velocity detail description of the near-surface model update amount. Specifically, the constraint strength is determined according to the size of the constraint factor. Preferably, the initial constraint factor is 0.1, so as to constrain the obtained velocity model to the velocity data similar to the near-surface survey structure. Usually, near-surface modeling requires multiple rounds of iterative inversion. In each round of inversion, the three-dimensional geological-velocity model data of this area is fixed, thereby constraining the accuracy of the solution result.

[0144] Next, convert the planar map data into binary three-dimensional data and introduce it into the near-surface tomography inversion matrix as a regularization term to constrain the near-surface velocity update direction and update amount.

[0145] S4: Generate a near-surface velocity model.

[0146] Specifically, when the total number of inversion iterations reaches a preset value, the inversion ends, output the established near-surface velocity model, and perform vertical data interception on the velocity model along the survey line direction of the work area to obtain multiple two-dimensional slice data at the same positions as the field reconnaissance. Compare the obtained two-dimensional planar slice data with the two-dimensional stratigraphic profile in step S2 and calculate their mean square error. If the mean square error is within the maximum allowable error range for this near-surface modeling, output the near-surface velocity model; if the error is large, return to step S3, increase the size of the constraint factor, generally twice the size, and perform velocity inversion again until the calculated mean square error is within the controllable range.

[0147] As can be seen from the above description, the embodiment of the present invention provides a tomography method based on near-surface constraints of geological outcrops, including: First, generate multiple two-dimensional stratigraphic profiles according to the field outcrop data of the target work area; among them, the two-dimensional stratigraphic profile data at least includes the layer velocity data of each stratum; then, generate the three-dimensional volume data of the target work area according to the multiple two-dimensional stratigraphic profiles; perform near-surface travel-time tomography inversion on the initial surface velocity model of the target work area according to the three-dimensional volume data and the pre-generated tomography matrix of the target work area to generate the near-surface velocity model of the target work area; finally, perform tomography operation on the target work area according to the near-surface velocity model.

[0148] The present invention aims at the shallow surface layer in exploration areas with complex seismic geological conditions such as the southwestern gobi area, desert area and piedmont zone. Based on the field geological outcrop survey data, the survey data is converted into velocity data to constrain the updating direction and updating amount of the near-surface tomography velocity modeling, thereby improving the geological rationality and accuracy of the near-surface velocity model.

[0149] Embodiment 4:

[0150] Based on the same inventive concept, the embodiment of the present application also provides a tomography device based on near-surface constraint of geological outcrops, which can be used to implement the method described in the above embodiments, such as the following embodiments. Since the principle of the tomography device based on near-surface constraint of geological outcrops to solve problems is similar to that of the tomography method based on near-surface constraint of geological outcrops, the implementation of the tomography device based on near-surface constraint of geological outcrops can refer to the implementation of the tomography method based on near-surface constraint of geological outcrops, and the repeated parts will not be described again. As used below, the term "unit" or "module" can be a combination of software and / or hardware that can achieve a predetermined function. Although the systems described in the following embodiments are preferably implemented in software, implementation in hardware, or a combination of software and hardware is also possible and contemplated.

[0151] The embodiment of the present invention provides a specific implementation manner of a tomography device based on near-surface constraint of geological outcrops that can implement the tomography method based on near-surface constraint of geological outcrops. Refer to Figure 16 , a tomography device based on near-surface constraint of geological outcrops includes:

[0152] A two-dimensional stratigraphic profile generation module 10, configured to generate a plurality of two-dimensional stratigraphic profiles according to the field outcrop data of the target work area; wherein, the two-dimensional stratigraphic profile data at least includes the layer velocity data of each stratum;

[0153] A three-dimensional volume data generation module 20, configured to generate three-dimensional volume data of the target work area according to the plurality of two-dimensional stratigraphic profiles;

[0154] A near-surface velocity model generation module 30, configured to perform near-surface traveltime tomography inversion on the initial surface velocity model of the target work area according to the three-dimensional volume data and the pre-generated tomography matrix of the target work area to generate the near-surface velocity model of the target work area;

[0155] A work area tomography module 40, configured to perform tomography operation on the target work area according to the near-surface velocity model.

[0156] In some embodiments of the present invention, the near-surface traveltime tomography inversion is in a multi-round iterative manner, and the near-surface velocity model generation module includes:

[0157] The tomography matrix generation unit of this round is used to perform ray tracing on the surface velocity model obtained from the surface travel-time tomography inversion of the previous round, so as to generate the tomography matrix for the surface travel-time tomography inversion of this round;

[0158] The update amount determination unit for the next round is used to determine the update amount of the surface velocity model for the surface travel-time tomography inversion of the next round according to the tomography matrix of the surface travel-time tomography inversion of this round;

[0159] The tomography inversion unit for the next round is used to perform the surface travel-time tomography inversion of the next round on the surface velocity model of this round according to the update amount and the three-dimensional volume data.

[0160] In some embodiments of the present invention, the update amount determination unit for the next round includes:

[0161] The solution generation unit is used to constrain the solution process of the tomography matrix of the surface travel-time tomography inversion of this round according to the three-dimensional volume data, so as to generate the solution of the tomography matrix of the surface travel-time tomography inversion of this round;

[0162] The update amount determination subunit is used to determine the update amount according to the solution.

[0163] In some embodiments of the present invention, a tomography device based on near-surface constraints of geological outcrops further includes:

[0164] The two-dimensional slice acquisition module is used to slice the near-surface velocity model to generate a plurality of two-dimensional slices;

[0165] The model accuracy inspection module is used to inspect the accuracy of the near-surface velocity model according to the difference between the plurality of two-dimensional geological profiles and the corresponding plurality of two-dimensional slices.

[0166] In some embodiments of the present invention, a tomography device based on near-surface constraints of geological outcrops further includes:

[0167] The two-dimensional profile correction module is used to correct the plurality of two-dimensional geological profiles according to the lithology, fracture development trend, rock porosity, and rock particle size of the target work area.

[0168] In some embodiments of the present invention, the three-dimensional volume data generation module includes:

[0169] The three-dimensional volume data generation unit is used to perform difference extrapolation on the plurality of two-dimensional geological profiles according to the work area coordinates of the target work area to generate the three-dimensional volume data.

[0170] In some embodiments of the present invention, the near two-dimensional slice acquisition module includes:

[0171] Two-dimensional slice acquisition hope, which is used to vertically slice the near-surface velocity model along the survey line direction of the target work area to obtain the multiple two-dimensional slices.

[0172] As can be seen from the above description, an embodiment of the present invention provides a tomography device based on near-surface constraints of geological outcrops, including: a two-dimensional stratigraphic profile generation module, which is used to generate multiple two-dimensional stratigraphic profiles according to the field outcrop data of the target work area; wherein, the two-dimensional stratigraphic profile data at least includes the layer velocity data of each stratum; a three-dimensional volume data generation module, which is used to generate three-dimensional volume data of the target work area according to the multiple two-dimensional stratigraphic profiles; a near-surface velocity model generation module, which is used to perform near-surface travel-time tomography inversion on the initial surface velocity model of the target work area according to the three-dimensional volume data and the pre-generated tomography matrix of the target work area to generate the near-surface velocity model of the target work area; a work area tomography module, which is used to perform tomography operation on the target work area according to the near-surface velocity model.

[0173] The tomography device based on near-surface constraints of geological outcrops provided by the embodiment of the present invention, on the basis of field geological outcrop survey data, converts the survey data into velocity data, which is used to constrain the update direction and update amount of near-surface tomography velocity modeling, thereby improving the geological rationality and accuracy of the near-surface velocity model.

[0174] Embodiment Five:

[0175] The embodiment of the present application also provides a specific implementation manner of an electronic device that can implement all steps in the above-mentioned tomography method based on near-surface constraints of geological outcrops. Refer to Figure 17 , the electronic device specifically includes the following contents:

[0176] A processor 1201, a memory 1202, a communication interface 1203, and a bus 1204;

[0177] Among them, the processor 1201, the memory 1202, and the communication interface 1203 complete mutual communication through the bus 1204; the communication interface 1203 is used to realize information transmission between related devices such as server-side devices and client-side devices;

[0178] The processor 1201 is used to call the computer program in the memory 1202. When the processor executes the computer program, it realizes all steps in the above-mentioned tomography method based on near-surface constraints of geological outcrops. For example, when the processor executes the computer program, it realizes the following steps:

[0179] Generate multiple two-dimensional stratigraphic profiles according to the field outcrop data of the target work area; wherein, the two-dimensional stratigraphic profile data at least includes the layer velocity data of each stratum;

[0180] Generate the 3D volume data of the target work area according to the multiple 2D stratigraphic profiles;

[0181] Perform near-surface traveltime tomography inversion on the initial surface velocity model of the target work area according to the 3D volume data and the pre-generated tomography matrix of the target work area to generate the near-surface velocity model of the target work area;

[0182] Perform tomography operation on the target work area according to the near-surface velocity model.

[0183] In some embodiments, the near-surface traveltime tomography inversion is in a multi-round iterative manner, and performing near-surface traveltime tomography inversion on the initial surface velocity model of the target work area according to the 3D volume data and the pre-generated tomography matrix of the target work area includes:

[0184] Perform ray tracing on the surface velocity model of the previous round of surface traveltime tomography inversion to generate the tomography matrix of the current round of surface traveltime tomography inversion;

[0185] Determine the update amount of the surface velocity model of the next round of surface traveltime tomography inversion according to the tomography matrix of the current round of surface traveltime tomography inversion;

[0186] Perform the next round of surface traveltime tomography inversion on the surface velocity model of the current round according to the update amount and the 3D volume data.

[0187] In some embodiments, determining the update amount of the surface velocity model of the next round of surface traveltime tomography inversion according to the tomography matrix of the current round of surface traveltime tomography inversion includes:

[0188] Constrain the solution process of the tomography matrix of the current round of surface traveltime tomography inversion according to the 3D volume data to generate the solution of the tomography matrix of the current round of surface traveltime tomography inversion;

[0189] Determine the update amount according to the solution.

[0190] In some embodiments, a tomography method based on near-surface constraint of geological outcrops further includes:

[0191] Slice the near-surface velocity model to generate a plurality of 2D slices;

[0192] Check the accuracy of the near-surface velocity model according to the difference between the multiple 2D stratigraphic profiles and the corresponding multiple 2D slices.

[0193] In some embodiments, before generating the 3D volume data of the target work area according to the multiple 2D stratigraphic profiles, it further includes:

[0194] Modify the multiple two-dimensional stratigraphic profiles according to the lithology, fracture development trend, rock porosity, and rock particle size of the target work area.

[0195] In some embodiments, generating three-dimensional volume data of the target work area based on the multiple two-dimensional stratigraphic profiles includes:

[0196] Performing interpolation extrapolation on the multiple two-dimensional stratigraphic profiles according to the work area coordinates of the target work area to generate the three-dimensional volume data.

[0197] In some embodiments, slicing the near-surface velocity model to generate multiple two-dimensional slices includes:

[0198] Vertically slice the near-surface velocity model along the survey line direction of the target work area to obtain the multiple two-dimensional slices.

[0199] Embodiment Six:

[0200] An embodiment of the present application further provides a computer-readable storage medium capable of implementing all steps in the tomography method based on near-surface constraints of geological outcrops in the above embodiments. A computer program is stored on the computer-readable storage medium. When the computer program is executed by a processor, all steps of the tomography method based on near-surface constraints of geological outcrops in the above embodiments are implemented. For example, when the processor executes the computer program, the following steps are implemented:

[0201] Generate multiple two-dimensional stratigraphic profiles based on the field outcrop data of the target work area; wherein, the two-dimensional stratigraphic profile data at least includes the layer velocity data of each stratum;

[0202] Generate three-dimensional volume data of the target work area based on the multiple two-dimensional stratigraphic profiles;

[0203] Perform near-surface traveltime tomography inversion on the initial surface velocity model of the target work area based on the three-dimensional volume data and the pre-generated tomography matrix of the target work area to generate the near-surface velocity model of the target work area;

[0204] Perform tomography operation on the target work area based on the near-surface velocity model.

[0205] In some embodiments, the near-surface traveltime tomography inversion is in a multi-round iterative manner. The performing near-surface traveltime tomography inversion on the initial surface velocity model of the target work area based on the three-dimensional volume data and the pre-generated tomography matrix of the target work area includes:

[0206] Perform ray tracing on the surface velocity model of the previous round of surface traveltime tomography inversion to generate the tomography matrix of the current round of surface traveltime tomography inversion;

[0207] Determine the update amount of the surface velocity model for the next round of surface travel-time tomography inversion based on the tomography matrix of the current round of surface travel-time tomography inversion;

[0208] Perform the next round of surface travel-time tomography inversion on the surface velocity model of the current round according to the update amount and the three-dimensional volume data.

[0209] In some embodiments, determining the update amount of the surface velocity model for the next round of surface travel-time tomography inversion based on the tomography matrix of the current round of surface travel-time tomography inversion includes:

[0210] Constrain the solution process of the tomography matrix of the current round of surface travel-time tomography inversion according to the three-dimensional volume data to generate the solution of the tomography matrix of the current round of surface travel-time tomography inversion;

[0211] Determine the update amount according to the solution.

[0212] In some embodiments, a tomography method based on near-surface constraints of geological outcrops further includes:

[0213] Slice the near-surface velocity model to generate a plurality of two-dimensional slices;

[0214] Check the accuracy of the near-surface velocity model according to the difference between the plurality of two-dimensional stratigraphic profiles and the corresponding plurality of two-dimensional slices.

[0215] In some embodiments, before generating the three-dimensional volume data of the target work area according to the plurality of two-dimensional stratigraphic profiles, it further includes:

[0216] Correct the plurality of two-dimensional stratigraphic profiles according to the lithology, fracture development trend, rock porosity, and rock particle size of the target work area.

[0217] In some embodiments, generating the three-dimensional volume data of the target work area according to the plurality of two-dimensional stratigraphic profiles includes:

[0218] Perform difference extrapolation on the plurality of two-dimensional stratigraphic profiles according to the work area coordinates of the target work area to generate the three-dimensional volume data.

[0219] In some embodiments, slicing the near-surface velocity model to generate a plurality of two-dimensional slices includes:

[0220] Vertically slice the near-surface velocity model along the survey line direction of the target work area to obtain the plurality of two-dimensional slices.

[0221] Each embodiment in this specification is described in a progressive manner. For the same or similar parts among the embodiments, reference can be made to each other, and the differences between each embodiment and other embodiments are emphasized. In particular, for the embodiments of hardware + program, since they are basically similar to the method embodiments, the description is relatively simple, and reference can be made to the relevant parts of the method embodiments for the relevant content.

[0222] The above describes specific embodiments of this specification. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recited in the claims can be performed in a different order than in the embodiments and still achieve the desired result. Additionally, the processes depicted in the figures do not necessarily require the particular order or sequential order shown to achieve the desired result. In certain embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0223] Although this application provides method operation steps such as in the embodiments or flowcharts, based on routine or non-creative labor, there can be more or fewer operation steps. The order of steps listed in the embodiments is only one way among many orderings of step execution and does not represent the only execution order. When the actual device or client product is executing, it can be executed in the order shown in the embodiments or figures or in parallel (such as in an environment with parallel processors or multithreaded processing).

[0224] For convenience of description, when describing the above device, it is divided into various modules according to functions for separate description. Of course, when implementing the embodiments of this specification, the functions of each module can be implemented in the same or multiple software and / or hardware, or the modules implementing the same function can be realized by a combination of multiple sub-modules or sub-units, etc. The device embodiments described above are only illustrative. For example, the division of the units is only a logical function division, and there can be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the displayed or discussed couplings or direct couplings or communication connections to each other can be through some interfaces. The indirect couplings or communication connections of the devices or units can be in electrical, mechanical or other forms.

[0225] Those skilled in the art also know that, in addition to implementing the controller in the form of pure computer-readable program code, the method steps can be logically programmed to enable the controller to implement the same functions in the form of logic gates, switches, application-specific integrated circuits, programmable logic controllers, embedded microcontrollers, etc. Therefore, such a controller can be regarded as a hardware component, and the devices included therein for implementing various functions can also be regarded as the structures within the hardware component. Or even, the devices for implementing various functions can be regarded as either software modules for implementing the method or structures within the hardware component.

[0226] In a typical configuration, a computing device includes one or more processors (CPUs), an input / output interface, a network interface, and memory.

[0227] The memory may include non-permanent memory in the form of computer-readable media, random access memory (RAM), and / or non-volatile memory such as read-only memory (ROM) or flash RAM. The memory is an example of computer-readable media.

[0228] Each embodiment in this specification is described in a progressive manner. The same or similar parts among the embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the system embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the description of the method embodiment. In the description of this specification, the description of reference terms such as "an embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the embodiments of this specification. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0229] The above is only the embodiment of the embodiments of this specification and is not used to limit the embodiments of this specification. For those skilled in the art, various changes and modifications can be made to the embodiments of this specification. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the embodiments of this specification shall be included within the scope of the claims of the embodiments of this specification.

Claims

1. A tomography method based on near-surface constraints of geological outcrops, characterized in that, Including: Generating a plurality of two-dimensional stratigraphic profiles based on the outcrop data of the target work area; wherein, the two-dimensional stratigraphic profile at least includes the layer velocity data of each stratum; Generating three-dimensional volume data of the target work area based on the plurality of two-dimensional stratigraphic profiles; Performing near-surface traveltime tomography inversion on the initial surface velocity model of the target work area according to the three-dimensional volume data and the pre-generated tomography matrix of the target work area to generate the near-surface velocity model of the target work area; Performing tomography operation on the target work area according to the near-surface velocity model.

2. The tomography method based on near-surface constraints of geological outcrops according to claim 1, characterized in that, The near-surface traveltime tomography inversion is in a multi-round iterative manner, and performing near-surface traveltime tomography inversion on the initial surface velocity model of the target work area according to the three-dimensional volume data and the pre-generated tomography matrix of the target work area includes: Performing ray tracing on the surface velocity model of the previous round of surface traveltime tomography inversion to generate the tomography matrix of the current round of surface traveltime tomography inversion; Determining the update amount of the surface velocity model of the next round of surface traveltime tomography inversion according to the tomography matrix of the current round of surface traveltime tomography inversion; Performing the next round of surface traveltime tomography inversion on the surface velocity model of the current round according to the update amount and the three-dimensional volume data.

3. The tomography method based on near-surface constraints of geological outcrops according to claim 2, characterized in that, Determining the update amount of the surface velocity model of the next round of surface traveltime tomography inversion according to the tomography matrix of the current round of surface traveltime tomography inversion includes: Constraining the solution process of the tomography matrix of the current round of surface traveltime tomography inversion according to the three-dimensional volume data to generate the solution of the tomography matrix of the current round of surface traveltime tomography inversion; Determining the update amount according to the solution.

4. The tomography method based on near-surface constraints of geological outcrops according to claim 1, characterized in that, Also including: Segmenting the near-surface velocity model to generate a plurality of two-dimensional slices; Checking the accuracy of the near-surface velocity model according to the difference between the plurality of two-dimensional stratigraphic profiles and the corresponding plurality of two-dimensional slices.

5. The tomography method based on near-surface constraints of geological outcrops according to claim 1, characterized in that, Before generating the three-dimensional volume data of the target work area according to the plurality of two-dimensional stratigraphic profiles, it also includes: Correcting the plurality of two-dimensional stratigraphic profiles according to the lithology, fracture development trend, rock porosity and rock particle size of the target work area.

6. The tomography method based on near-surface constraints of geological outcrops according to any one of claims 1 to 5, characterized in that, Generating the three-dimensional volume data of the target work area according to the plurality of two-dimensional stratigraphic profiles includes: Performing difference extrapolation on the plurality of two-dimensional stratigraphic profiles according to the work area coordinates of the target work area to generate the three-dimensional volume data.

7. The tomography method based on near-surface constraints of geological outcrops according to claim 4, characterized in that, Segmenting the near-surface velocity model to generate a plurality of two-dimensional slices includes: Vertically segmenting the near-surface velocity model along the survey line direction of the target work area to obtain the plurality of two-dimensional slices.

8. A tomography device based on near-surface constraints of geological outcrops, characterized in that, Including: A two-dimensional stratigraphic profile generation module, configured to generate a plurality of two-dimensional stratigraphic profiles based on the outcrop data of the target work area; wherein, the two-dimensional stratigraphic profile at least includes the layer velocity data of each stratum; A three-dimensional volume data generation module, configured to generate three-dimensional volume data of the target work area according to the plurality of two-dimensional stratigraphic profiles; A near-surface velocity model generation module, configured to perform near-surface traveltime tomography inversion on an initial surface velocity model of the target work area according to the three-dimensional volume data and the tomography matrix of the pre-generated target work area, so as to generate a near-surface velocity model of the target work area; A work area tomography module, configured to perform tomography operation on the target work area according to the near-surface velocity model.

9. An electronic device, comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, characterized in that,When the processor executes the program, the steps of the tomography method based on near-surface constraints of geological outcrops according to any one of claims 1 to 7 are implemented.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, the steps of the tomography method based on near-surface constraints of geological outcrops according to any one of claims 1 to 7 are implemented.

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