A basin basement relief gravity inversion method, system, medium, and device

Abstract

The application discloses a basin basement relief gravity inversion method, system, medium and equipment, relates to the field of geophysical exploration, and comprises the following steps: taking the difference between the Bouguer gravity anomaly of a to-be-measured area and the gravity anomaly caused by the Moho relief as an initial basement gravity anomaly; based on the acquired reduction-to-pole magnetic force anomaly, the Bouguer gravity anomaly and the seismic profile data, using 2.5D man-machine interaction inversion to acquire the density, the magnetization intensity parameter and the basement depth point; based on the density and the magnetization intensity parameter, using the Poisson formula to determine the magnetic source gravity anomaly; taking the difference between the acquired initial basement gravity anomaly and the magnetic source gravity anomaly as a corrected basement gravity anomaly; taking the basement depth point as a constraint, using the corrected basement gravity anomaly to perform basement depth inversion, and acquiring the basin basement relief gravity inversion result.

Description

Technical Field

[0001] This invention relates to the field of geophysical exploration, and in particular to a method, system, medium, and equipment for gravity inversion of basin basement undulations. Background Technology

[0002] The basement, as the crystalline basement or ancient metamorphic rock series of a sedimentary basin, directly controls the basin's tectonic pattern, sedimentary thickness, and spatial distribution through its depth and undulation, making it a key parameter for basin analysis and tectonic evolution research. Basement depth obtained through gravity anomaly inversion can provide a basis for classifying uplifts, depressions, and fault systems, and plays a crucial supporting role in evaluating source rock distribution, trap development conditions, and hydrocarbon accumulation potential. It also provides key evidence for regional resource exploration, deep structural research, and geological modeling. Basins in low-exploration marine areas lack high-precision seismic and drilling data, and rely primarily on gravity data inversion to determine basement depth.

[0003] Existing technologies employ the following method for basement gravity anomaly inversion: First, the Bouguer gravity anomaly is obtained by eliminating topographic relief or seawater gravity effects from the free-space gravity anomaly. Then, the influence of the Moho discontinuity is eliminated or weakened from the Bouguer gravity anomaly to obtain the basement gravity anomaly. Finally, the basement gravity anomaly is inverted to obtain the basement depth. However, the gravity anomaly used for inversion usually includes gravity effects other than basement depth fluctuations, such as magnetic source gravity anomalies caused by basement lithological inhomogeneity. Existing methods only consider basement depth fluctuations caused by the Moho discontinuity, ignoring the influence of basement lithological inhomogeneity, which leads to significant errors in the basement depth inversion results. Summary of the Invention

[0004] This invention provides a method, system, medium, and equipment for gravity inversion of basin basement undulations, to solve the aforementioned problems in the prior art, namely, how to improve the accuracy of basement depth inversion in the prior art. This invention provides a method for gravity inversion of basin basement undulations, which includes: The difference between the Bouguer gravity anomaly in the area to be measured and the gravity anomaly caused by the undulation of the Moho surface is used as the initial base gravity anomaly. Based on the acquired magnetic anomalies, Bouguer gravity anomalies, and seismic profile data, 2.5D human-computer interactive inversion was used to obtain density, magnetization parameters, and basement depth points. Based on the density and magnetization parameters, the magnetic source gravity anomaly was determined using the Poisson formula. The difference between the initial basement gravity anomaly and the magnetic source gravity anomaly is used as the corrected basement gravity anomaly. The extracted basement depth points are used as constraints, and the corrected basement gravity anomaly is used to perform basement depth inversion to obtain the basin basement undulation gravity inversion results.

[0005] Optionally, the acquisition of the magnetic source gravity anomaly specifically includes: A geological body model was constructed based on seismic profile data. Using 2.5D human-computer interaction, gravity and magnetic anomalies caused by the geological body model were determined. The geological body model was then optimized until the magnetic and gravity anomalies it caused fit the actual polar magnetic anomalies and Bouguer gravity anomaly curves. The optimized geological body model was then determined. Based on the optimized geological body model, density differences were obtained. and magnetization difference parameter; Optical polarization magnetic anomaly Perform a two-dimensional Fourier transform to determine the transformed... ,based on Binding density difference and magnetization difference The parameters are obtained by acquiring the magnetic source gravity anomaly in the following manner: ; in, This is due to an anomaly in the gravity of the magnetic source. For polarization magnetic anomaly The two-dimensional Fourier transform; The two-dimensional spectrum of the magnetic source gravity anomaly; Let be the wave number along the x and y directions; Radial wave number; It is the gravitational constant; For density difference; Permeability of free space; Poor magnetization; Through calculation Perform an inverse Fourier transform to determine the gravity anomaly of the magnetic source at any measurement point i.

[0006] Optionally, the gravity anomaly can be determined by forward modeling based on the acquired Moho depth data and the crust-mantle density difference; wherein the crust-mantle density difference is the difference between the crustal weighted density and the mantle density.

[0007] Optionally, the acquisition of the Bouguer gravity anomaly specifically includes: The area to be tested is divided into multiple three-dimensional prism elements. For each three-dimensional prism element, its... Upper and lower limits of three-dimensional integrals The gravity anomaly generated by each three-dimensional prism element at the gravity measurement point is determined using the following formula: ; The gravity anomalies generated by each three-dimensional prism element at the gravity measurement point are linearly superimposed to determine the gravity effect generated by each three-dimensional prism element at the gravity measurement point, specifically including: ; Where G is Newton's gravitational constant, ( ) are the coordinates of the i-th measuring point; The coordinates of any infinitesimal element within the triangular prism are given; the coordinate range of the j-th upright hexahedron is given. ; Due to density difference, This represents the gravitational effect at the i-th measuring point. This represents the gravity anomaly caused by the j-th segmented three-dimensional prism at the i-th measuring point; The difference between the obtained gravity anomaly and the gravity effect is taken as the Bouguer gravity anomaly.

[0008] Optionally, the acquisition of the gravity anomaly caused by the Moho surface undulation specifically includes: The Moho depth data was resampled to a 1km×1km grid, and the average Moho depth H0 of the area to be measured was used as the top interface, and the actual Moho depth was used as the bottom interface. Combined with the obtained density difference, the gravity anomaly caused by the undulation of the Moho at any measuring point was determined.

[0009] Optionally, the acquisition of the polarization magnetic anomaly specifically includes: The magnetic anomaly was determined by performing polarization processing on the acquired magnetic anomaly data.

[0010] Optionally, the step of determining the polarization magnetic anomaly by performing polarization processing on the acquired magnetic anomaly data specifically includes: Perform a Fourier transform on the magnetic anomaly data to determine the transformed magnetic anomaly data; A frequency-domain polarization factor is introduced, and the product of the transformed magnetic anomaly data and the frequency-domain polarization factor is subjected to an inverse Fourier transform to determine the polarization magnetic anomaly.

[0011] This invention provides a basin basement undulation gravity inversion system to realize the above-mentioned basin basement undulation gravity inversion method.

[0012] The present invention provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the above-described method for gravity inversion of basin basement undulations.

[0013] The present invention provides a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the program, it implements the above-mentioned basin basement undulation gravity inversion method.

[0014] Compared with existing technologies, the beneficial effects of this invention are as follows: This invention provides a method for gravity inversion of basin basement undulations. This method obtains basement density and magnetization parameters by jointly analyzing seismic profiles, magnetic polarization anomalies, and Bouguer gravity anomalies, and by using 2.5D human-computer interactive inversion technology. Based on these two parameters, magnetic source gravity anomalies that characterize the gravity effect of basement lithological inhomogeneity can be obtained. By eliminating magnetic source gravity anomalies from the initial basement gravity anomalies, reliable basement gravity anomalies are obtained. Inversion is performed under the constraint of known basement depth to obtain the corresponding inversion results, thereby improving the accuracy of basin basement depth inversion. Attached Figure Description

[0015] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0016] Figure 1 A flowchart of a gravity inversion method for basin basement undulation provided in an embodiment of the present invention; Figure 2 This is a Bouguer gravity anomaly diagram provided in an embodiment of the present invention; Figure 3 This is a polarization magnetic anomaly diagram provided in an embodiment of the present invention; Figure 4 Moho depth map provided for embodiments of the present invention; Figure 5 This is a gravity anomaly diagram caused by the undulation of the Moho surface, provided in an embodiment of the present invention. Figure 6 This is an initial base gravity anomaly diagram provided in an embodiment of the present invention; Figure 7 A comparison diagram of initial base gravity anomaly and seismic profile provided in an embodiment of the present invention; Figure 8 This is a 2.5D human-computer interaction inversion diagram provided in an embodiment of the present invention; Figure 9 This is a magnetic source gravity anomaly diagram provided in an embodiment of the present invention; Figure 10 The corrected base gravity anomaly provided in the embodiments of the present invention; Figure 11 A substrate depth map provided for an embodiment of the present invention; Figure 12 A schematic diagram of a computer device for the basin basement undulation gravity inversion method provided in an embodiment of the present invention. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0018] The technical solution of the present invention and how the technical solution of the present invention solves the above-mentioned technical problems are described in detail below with specific embodiments. These specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments. The embodiments of the present invention will now be described with reference to the accompanying drawings.

[0019] Example 1 Figure 1 This is a flowchart of a gravity inversion method for basin basement undulations provided in an embodiment of the present invention, as shown below. Figure 1 As shown in this embodiment, a gravity inversion method for basin basement undulations includes: S1: The difference between the Bouguer gravity anomaly of the area to be measured and the gravity anomaly caused by the undulation of the Moho surface is used as the initial base gravity anomaly.

[0020] For example, free-space gravity anomaly, magnetic anomaly data ΔT, Moho depth data, and seismic profiles of the area to be measured can be collected. The collected free-space gravity anomalies are then processed to eliminate the gravity effects of topographic relief and seawater, resulting in Bouguer gravity anomalies. Specifically, the method for eliminating the influence of topographic relief on land is as follows: using large-scale SRTM 90m resolution land DEM data, with sea level (z=0) as the bottom interface and the DEM data as the top interface, the large-scale topographic area is divided into prism units with a horizontal dimension of 90m × 90m. The gravity effect generated by each three-dimensional prism unit at the gravity measurement point is calculated using the prism gravity forward modeling formula. The method for eliminating the influence of seawater gravity on the sea area is as follows: using sea level (z=0) as the top interface and ETOPO1 seabed topography as the bottom interface, the sea area is divided into 1km × 1km three-dimensional prism units. Both the land topographic mass gravity effect and the seawater layer gravity effect are calculated using the three-dimensional prism forward modeling formula.

[0021] For the i-th gravity calculation point A, the gravity effect caused by topography or seawater at this measuring point can be obtained by the following formula: (1) in, This represents the gravitational effect at the i-th measuring point. The expression for the gravity anomaly caused by the j-th subdivision of the three-dimensional prism at the i-th measuring point is: (2) Where G is Newton's gravitational constant, with a value of 6.67 × 10⁻⁶. -11 N·m 2 / kg 2 ; ( ) are the coordinates of the i-th measuring point; The coordinates of any infinitesimal element within the triangular prism are given; the coordinate range of the j-th upright hexahedron is given. ; For density differences, the density of the terrestrial region is taken as 2.76 g / cm³, which is the average density of the Earth's crust. 3 The difference, in the context of the sea area, is the difference between the density of seawater and the density of the underlying sedimentary layer, and is generally taken as -1.27 g / cm³. 3 .

[0022] Obtain the gravitational effect caused by the topography or seawater at each measuring point. Then, the Bouguer gravity anomaly can be obtained by eliminating this gravitational effect from the free-space gravity anomaly. The Bouguer gravity anomaly at the i-th gravity calculation point. Calculate using the following formula:

[0023] (3) in: The Bouguer gravity anomaly is located at the i-th gravity calculation point. This represents the free-space gravity anomaly collected at the i-th gravity calculation point.

[0024] For example, the magnetic anomaly can be obtained by eliminating the influence of oblique magnetization offset on the collected magnetic anomaly data ΔT. The method for eliminating oblique magnetization offset is as follows: based on the geomagnetic reference field IGRF model, calculate the geomagnetic dip angle I and geomagnetic declination D of the area to be measured, and use the frequency domain polarization algorithm to calculate the magnetic anomaly.

[0025] When calculating the magnetic anomaly of the polarization, the measured magnetic anomaly data ΔT(x,y) is first subjected to a Fourier transform to obtain F(K). x ,K y— ), multiplied by the frequency domain polarization factor RTP(K x ,K y ) Then, an inverse Fourier transform is performed to obtain the polarization magnetization anomaly. Frequency domain polarization factor. RTP(K x ,K y ) The calculation formula is:

[0026] (4) in, Wavenumber (frequency domain coordinates). ; Wavenumber direction angle ( Azimuth angle in the Fourier domain); The imaginary unit; , These represent the dip and deflection angles of the geomagnetic field at the observation location, respectively. , These are the tilt angle and deflection angle of the magnetization intensity of the magnetic body, respectively.

[0027] S2: Based on the depth data of the Moho discontinuity and the density difference between the crust and mantle, forward modeling is used to determine the gravity anomaly caused by the undulation of the Moho discontinuity. The difference between the Bouguer gravity anomaly and the gravity anomaly is used as the initial basement gravity anomaly.

[0028] For example, the density difference between the crust and mantle (referred to as the crust-mantle density difference) Δρ can be calculated based on the crustal density and mantle density in the CRUST1.0 model. The mantle density is directly derived from the mantle density tested in the CRUST1.0 model, while the crustal density is obtained by calculating the weighted average density based on the thickness and density of the upper, middle, and lower crust in the CRUST1.0 model.

[0029] mantle density difference The calculation formula is: (5) (6) in, Weighted density of the Earth's crust; The density of the mantle; These represent the densities of the upper, middle, and lower crust, respectively. These represent the thicknesses of the upper, middle, and lower crust, respectively.

[0030] For example, the gravity anomaly caused by the Moho discontinuity can be obtained by forward modeling using the collected Moho depth data and the calculated crust-mantle density difference. The specific calculation method is as follows: the Moho depth data is resampled to a 1km×1km grid, and the average Moho depth H0 of the area to be measured is obtained. The average Moho depth H0 is used as the top interface, the actual Moho depth is used as the bottom interface, and the density difference is calculated using the density difference obtained by equation (5). The same calculation formula (i.e., formulas 1~2) as the gravity effect of land topography mass and seawater layer gravity is used to calculate the gravity anomaly caused by the Moho discontinuity at any measuring point. .

[0031] Subtracting the gravity anomaly caused by the Mohorovičić discontinuity from the Bouguer gravity anomaly yields the initial base gravity anomaly at the i-th gravity observation point: (7) For example, the initial basement gravity anomaly and polarization magnetic anomaly corresponding to the location of the collected seismic profile can be extracted. The seismic profile and the basement gravity anomaly profile can be compared and analyzed to confirm the correlation between the basement depth undulation reflected by the seismic profile and the basement gravity anomaly (the deeper the basement, the smaller the corresponding basement gravity anomaly and the better the correlation, and vice versa). Combined with the Bouguer gravity anomaly and polarization magnetic anomaly planar map obtained in the first step, the polarization magnetic anomaly can be used to determine the existence of lithological differences in the basement.

[0032] S2: Based on the acquired polarization magnetic anomaly, Bouguer gravity anomaly, and seismic profile data, 2.5D human-computer interactive inversion is used to obtain density, magnetization parameters, and basement depth points. Based on the density and magnetization parameters, the magnetic source gravity anomaly is determined using the Poisson formula.

[0033] For example, the seismic profile collected in the first step can be input into the 2.5D human-computer interactive inversion platform as a constraint to help establish a stratigraphic model (all are polygonal cross-section models), and the gravity and magnetic anomalies extracted along the profile can be input as constraints for model establishment. The actual coordinates of the seismic profile are imported into the 2.5D human-computer interactive inversion platform. Then, different stratigraphic models are established based on the layering and morphology of each stratum in the seismic profile. The actual stratigraphic density and magnetization of the area to be measured are filled into each stratum. The platform uses the 2.5D polygonal cross-section model gravity and magnetic anomaly forward modeling formula to obtain the gravity and magnetic anomalies caused by the stratigraphic model in real time. The model is adjusted, and the fitting between the gravity and magnetic anomalies obtained by the model forward model and the input gravity and magnetic anomalies is observed. When both gravity and magnetic anomalies fit well, the final stratigraphic and basement models are obtained.

[0034] The formula for forward modeling gravity anomalies is as follows: (8) in, G represents the gravity anomaly obtained from the established human-computer interaction at any gravity point p on the cross-section; G is Newton's gravitational constant. N represents the density of the polygonal cross-section model; N is the number of sides of the polygonal cross-section (vertices are numbered sequentially, sides...). Connect vertices and (and the vertex 1 corresponding to N+1 is closed). No. The angle between the edge and the horizontal direction (x-axis); Y1 and Y2 are the coordinates of the two end faces of the prism along the direction (y-axis) (usually, if the section where the observation point is located is y=0, then Y1 and Y2 are positive values, representing the extension distance of the prism in the negative y direction and the positive y direction, respectively). For the first The gravitational effect of the strip (where Y is the upper limit of integration, i.e., Y1 or Y2).

[0035] For example, the forward modeling formula for magnetic anomalies is as follows: (9) in, The magnetic anomaly is obtained at any gravity point p on the cross section through the established human-computer interaction. and Let be the dip angle and deflection angle of the Earth's magnetic field, respectively; , and These are the three components of the magnetic anomaly, calculated using the following formula: (10) (11) (12) in, The permeability of free space (4π×10⁻⁶) -7 H / m); The edge number (polygon vertices are numbered sequentially). From 1 to N, edge Connect vertices and Vertex N+1 is vertex 1). For the first The angle between the strip edge and the horizontal direction (X-axis); M is the magnitude of the magnetization vector (unit: A / m). , , These are the three components of magnetization; , , The first The three components of the magnetic effect of the strip edge.

[0036] A basement lithology model consisting of polygonal cross-section models is established below the stratigraphic model. Different densities and magnetization intensities are filled into the polygonal cross-sections corresponding to different basement lithology models. The 2.5D human-computer interaction inversion platform automatically calculates the gravity anomalies and magnetic anomalies caused by the above models according to the forward modeling formulas in (8)~(12).

[0037] For example, based on the fitting error between the gravity and magnetic anomalies modeled in forward modeling and the extracted basement gravity anomaly profile and polarization magnetic anomaly profile, the corner coordinates, i.e. density and magnetization parameters, of the polygonal cross-section model representing the basement lithology can be continuously adjusted so that the modeled anomalies match the actual initial basement gravity and polarization magnetic anomalies. Finally, the density and magnetization of the model reflect the density and magnetization of the basement lithology inhomogeneity, which are used to calculate the gravity anomalies caused by the inhomogeneity of the basement lithology.

[0038] For example, the magnetic anomaly of the polarization can be used as a basis to calculate the gravity anomaly of the magnetic source according to the Poisson formula, based on the density difference and magnetization difference obtained by inversion using 2.5D human-computer interaction. The specific steps are as follows: first, the magnetic anomaly of the polarization is gridded, and trend terms and noise are removed to obtain spatial domain discrete interface fluctuation data. The calculation is performed using Fast Fourier Transform (FFT). Constructing wavenumber grids Wave number point calculation, traversing all wave number pairs ( Then, the gravity spectrum is calculated point by point. The formula for calculating the gravity anomaly of the magnetic source is: (13) in, For polarization magnetic anomaly The two-dimensional Fourier transform; The two-dimensional spectrum of the magnetic source gravity anomaly; Let be the wave number along the x and y directions; Radial wave number; It is the gravitational constant; For density difference; Permeability of free space; The magnetization is poor.

[0039] The specific steps for calculating the gravity anomaly of the magnetic source are as follows: First, the measured magnetic force data is gridded, and trend terms and noise are removed to obtain discrete interface undulation data in the spatial domain. The calculation is performed using Fast Fourier Transform (FFT). Constructing wavenumber grids Wave number point calculation, traversing all wave number pairs ( Substitute into formula (13) to calculate the gravity spectrum point by point. .

[0040] The result obtained by calculating the above formula The inverse Fourier transform can be used to obtain the gravity anomaly of the magnetic source at any measurement point i. .

[0041] S3: The difference between the initial basement gravity anomaly and the magnetic source gravity anomaly is used as the corrected basement gravity anomaly; the extracted basement depth points are used as constraints, and the corrected basement gravity anomaly is used to perform basement depth inversion to obtain the basin basement undulation gravity inversion results.

[0042] For example, the corrected base gravity anomaly can be obtained by subtracting the magnetic source gravity anomaly from the initial base gravity anomaly. : (14) For example, the present invention uses the obtained corrected base gravity anomaly, combined with the base depth points extracted from the 2.5D human-computer interaction inversion profile. As a constraint, the basement depth is inverted. The inversion method used is a gravity inversion method based on the estimation of density interface parameters with known depth estimation constraints. The process for inverting the basement depth is as follows:

[0043] (1) From the known depth Corrected base gravity anomaly at known depth points linear relationship between Fit an initial model of the interface depth: (15) In the formula, Let be the initial value of the interface depth at the i-th gravity observation point obtained from the linear relationship. and These are the slope and intercept obtained from fitting the linear relationship, respectively.

[0044] (2) Calculate the initial value of the density interface according to equations (1) and (2). Caused gravity anomaly In the calculation, the bottom interface is the initial value of the density interface, and the top interface is the average depth of the initial value of the density interface.

[0045] (3) For known depths First estimate of basement depth at location Deviation and first-fit gravity anomaly Linear regression of the bias: (16) The interface depth is updated according to the slope using the following formula. (17) In equations (23) to (24), and These are the slope and intercept obtained from fitting the linear relationship, respectively; For the updated interface depth, and These represent the actual base gravity anomaly and the forward-fitted gravity anomaly at the i-th gravity measurement point, respectively. At that time, the updated interface depth will be... As the final result, if the deviation is large, proceed to the second step to recalculate the gravity anomaly.

[0046] Example 2 To enable those skilled in the art to better understand the technical solutions in this application, the following explanation uses data from a basin in a certain region as an example.

[0047] (1) The calculated Bouguer gravity anomaly and polarization magnetic anomaly are shown in the figure. Figure 2 , Figure 3 ( Figure 3 The red line indicates the location of the seismic profile.

[0048] (2) The crust-mantle density difference Δρ was calculated based on the CRUST1.0 model, using the collected Moho depth data (such as...). Figure 4 (as shown) and the calculated crust-mantle density difference forward modeling yields the gravity anomaly caused by the Mohorovičić discontinuity undulation (such as...). Figure 5 As shown), the initial basement gravity anomaly is obtained by subtracting the gravity anomaly caused by the Moho surface undulation from the calculated Bouguer gravity anomaly (as shown). Figure 6 (As shown).

[0049] (3) Extract the basement gravity anomaly profile and polarization magnetic anomaly profile corresponding to the seismic profile, and compare and analyze the seismic profile with the basement gravity anomaly profile (e.g., Figure 7 As shown), it was confirmed that the correlation between the basement depth undulations reflected in the seismic profile and the basement gravity anomaly was poor, combined with polarization magnetic anomalies (such as... Figure 3 Analysis (as shown) suggests that there are differences in physical properties in the basement lithology.

[0050] (4) Using the extracted basement gravity anomaly profile and polarization magnetic anomaly profile combined with the stratigraphic morphology in the collected seismic profiles, a 2.5D interactive inversion was performed. Based on the inversion results (such as...), Figure 8 As shown, the specific physical property differences of the substrate were determined, with a density difference of 0.37 g / cm3 and a magnetic difference of 3 A / m.

[0051] (5) Utilizing the abnormal magnetic force of the polarization pole (e.g. Figure 3 (As shown) and using the density difference and magnetic difference obtained from 2.5D human-computer interaction inversion as the basis for calculating the magnetic source gravity anomaly (such as... Figure 9 As shown), the corrected base gravity anomaly is obtained by subtracting the magnetic source gravity anomaly from the initial base gravity anomaly (as shown). Figure 10 (As shown).

[0052] (6) Using the basement depth points extracted from the corrected basement gravity anomaly combined with the 2.5D human-computer interactive inversion profile as constraints, the basement depth (e.g.) is inverted. Figure 11 (As shown).

[0053] The above describes one or more embodiments of the basin basement undulation gravity inversion method provided in this specification. Based on the same idea, this specification also provides a corresponding basin basement undulation gravity inversion system. Specific limitations of the basin basement undulation gravity inversion system can be found in the limitations of the basin basement undulation gravity inversion method described above, and will not be repeated here. Each module in the above-described basin basement undulation gravity inversion system can be implemented entirely or partially through software, hardware, or a combination thereof. Each module can be embedded in or independent of the processor in a computer device in hardware form, or stored in the memory of a computer device in software form, so that the processor can call and execute the operations corresponding to each module.

[0054] The present invention also provides a computer-readable storage medium storing a computer program that can be used to execute the above-described basin basement undulation gravity inversion method.

[0055] The present invention also provides Figure 12 The schematic diagram of the computer device shown is as follows: Figure 12 As shown, at the hardware level, the computer device includes a processor, an internal bus, a network interface, memory, and non-volatile memory, and may also include other hardware required for business operations. The processor reads the corresponding computer program from the non-volatile memory into memory and then runs it to implement the basin basement undulation gravity inversion method provided in the above embodiment.

[0056] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium, and when executed, it can include the processes of the embodiments of the methods described above. Any references to memory, storage, databases, or other media used in the embodiments provided by this invention can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, or optical storage, etc. Volatile memory can include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM), etc.

[0057] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this invention.

Claims

1. A method for gravity inversion of basin basement undulations, characterized in that, include: The difference between the Bouguer gravity anomaly in the area to be measured and the gravity anomaly caused by the undulation of the Moho surface is used as the initial base gravity anomaly. Based on the acquired magnetic anomalies, Bouguer gravity anomalies, and seismic profile data, 2.5D human-computer interactive inversion was used to obtain density, magnetization parameters, and basement depth points. Based on the density and magnetization parameters, the magnetic source gravity anomaly was determined using the Poisson formula. The difference between the initial base gravity anomaly and the magnetic source gravity anomaly is used as the corrected base gravity anomaly. The extracted basement depth points are used as constraints, and the basement depth is inverted by correcting the basement gravity anomaly to obtain the gravity inversion results of the basin basement undulation.

2. The basin basement undulation gravity inversion method as described in claim 1, characterized in that, The acquisition of the magnetic source gravity anomaly specifically includes: A geological body model was constructed based on seismic profile data. Using 2.5D human-computer interaction, gravity and magnetic anomalies caused by the geological body model were determined. The geological body model was then optimized until the magnetic and gravity anomalies it caused fit the actual polar magnetic anomalies and Bouguer gravity anomaly curves. The optimized geological body model was then determined. Based on the optimized geological body model, density differences were obtained. and magnetization difference parameter; Optical polarization magnetic anomaly Perform a two-dimensional Fourier transform to determine the transformed... ,based on Binding density difference and magnetization difference The parameters are obtained by acquiring the magnetic source gravity anomaly in the following manner: ； in, This is due to an anomaly in the gravity of the magnetic source. For polarization magnetic anomaly The two-dimensional Fourier transform; The two-dimensional spectrum of the magnetic source gravity anomaly; Let be the wave number along the x and y directions; Radial wave number; It is the gravitational constant; For density difference; Permeability of free space; Poor magnetization; Through calculation Perform an inverse Fourier transform to determine the gravity anomaly of the magnetic source at any measurement point i.

3. The basin basement undulation gravity inversion method as described in claim 1, characterized in that, Based on the acquired Moho depth data and the crust-mantle density difference, the gravity anomaly is determined by forward modeling; wherein, the crust-mantle density difference is the difference between the crustal weighted density and the mantle density.

4. The basin basement undulation gravity inversion method as described in claim 1, characterized in that, The acquisition of the Bouguer gravity anomaly specifically includes: The area to be tested is divided into multiple three-dimensional prism elements. For each three-dimensional prism element, its... Upper and lower limits of three-dimensional integrals The gravity anomaly generated by each three-dimensional prism element at the gravity measurement point is determined using the following formula: ； The gravity anomalies generated by each three-dimensional prism element at the gravity measurement point are linearly superimposed to determine the gravity effect generated by each three-dimensional prism element at the gravity measurement point, specifically including: ； Where G is Newton's gravitational constant, ( ) are the coordinates of the i-th measuring point; The coordinates of any infinitesimal element within the triangular prism are given; the coordinate range of the j-th upright hexahedron is given. ; Due to density difference, This represents the gravitational effect at the i-th measuring point. This represents the gravity anomaly caused by the j-th segmented three-dimensional prism at the i-th measuring point; The difference between the obtained gravity anomaly and the gravity effect is taken as the Bouguer gravity anomaly.

5. The basin basement undulation gravity inversion method as described in claim 1, characterized in that, The acquisition of the gravity anomaly caused by the Mohorovičić discontinuity undulation specifically includes: The Moho depth data was resampled to a 1km×1km grid, and the average Moho depth H0 of the area to be measured was used as the top interface, and the actual Moho depth was used as the bottom interface. Combined with the obtained density difference, the gravity anomaly caused by the undulation of the Moho at any measuring point was determined.

6. The basin basement undulation gravity inversion method as described in claim 1, characterized in that, The acquisition of the polarization magnetic anomaly specifically includes: The magnetic anomaly was determined by performing polarization processing on the acquired magnetic anomaly data.

7. The basin basement undulation gravity inversion method as described in claim 6, characterized in that, The step of determining the magnetic anomaly by performing polarization processing on the acquired magnetic anomaly data specifically includes: Perform a Fourier transform on the magnetic anomaly data to determine the transformed magnetic anomaly data; A frequency-domain polarization factor is introduced, and the product of the transformed magnetic anomaly data and the frequency-domain polarization factor is subjected to an inverse Fourier transform to determine the polarization magnetic anomaly.

8. A gravity inversion system for basin basement undulation, characterized in that, Implement the basin basement undulation gravity inversion method as described in any one of claims 1-7.

9. A computer-readable storage medium, characterized in that, The storage medium stores a computer program, which, when executed by a processor, implements the basin basement undulation gravity inversion method according to any one of claims 1-7.

10. A computer device, characterized in that, It includes a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the basin basement undulation gravity inversion method according to any one of claims 1-7.

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