A layer-leveling gravity anomaly extraction method, device and storage medium

Abstract

The present invention mainly proposes a layer-flattening gravity anomaly extraction method, which includes constructing a seismic profile using seismic data of a target area and performing stratigraphic interpretation; determining a layer-flattening reference surface and its depth; performing gravity stripping based on the layer-flattening reference surface and its depth to obtain a layer-flattening gravity anomaly with the layer-flattening reference surface as the deepest stripping surface; calculating the regional gravity field of the target area using pre-acquired terrain elevation data, and removing the influence of the regional gravity field on the layer-flattening gravity anomaly to obtain a layer-flattening residual gravity anomaly; performing downward extension processing on the layer-flattening residual gravity anomaly, with the downward extension depth being the depth of the layer-flattening reference surface, to obtain the layer-flattening gravity anomaly of the target area. The present invention obtains a layer-flattening gravity anomaly with the layer-flattening reference surface as the deepest stripping surface and the apparent observation surface by improving the gravity stripping method and combining it with the downward extension method. The layer-flattening gravity anomaly more intuitively and accurately reflects the stratigraphic structure below the layer-flattening reference surface.

Description

Technical Field

[0001] The present invention relates to the field of geological exploration technology, and in particular to a layer-leveling gravity anomaly extraction method, device and storage medium. Background Art

[0002] As oil and gas exploration and development continue, exploration technology research continues to target deeper targets. Because the resolution of all geophysical methods decreases with depth, despite ongoing research into effective exploration methods and technologies for deeper targets, progress in geophysical technology has never kept pace with the exploration performance requirements of oilfield companies. Seismic data is the dominant high-resolution exploration method in the oil and gas industry and plays a crucial role in oil and gas exploration. However, the signal-to-noise ratio of seismic data decreases with increasing depth, making it impossible to obtain reliable deep structural information in some deep basins, hindering deep oil and gas exploration and development efforts. Bouguer gravity anomalies, reflecting density heterogeneity at all depths, encompass information from both shallow and deep layers. They are typically obtained through the acquisition and calculation of gravity data. Although gravity methods also experience a decrease in gravity information with increasing depth, Bouguer gravity anomalies still contain information about deep structures, making them suitable for studying deep structures. Using gravity methods to study deep structures requires first extracting residual gravity anomalies that contain deep structural information. However, due to the superposition of gravity effects of mid- and shallow-layer inhomogeneities, extracting residual gravity anomalies that mainly reflect deep structures is extremely difficult.

[0003] Several methods are currently available for extracting deep structural gravity anomalies. One is the downward continuation method, which uses data processing to convert surface-observed Bouguer gravity anomalies into gravity anomalies equivalent to those observed at a specific depth. However, while this method enhances deep information, it also amplifies information from intermediate and shallow layers, significantly interfering with this deeper information and severely impacting the study of deep targets. Another method is the stripping method, which utilizes depth data of intermediate and shallow stratigraphic interfaces interpreted from seismic data, along with density data converted from seismic layer velocities or measured from well logging and rock sampling, to forward-model the gravity effects of intermediate and shallow layers and remove them from the Bouguer gravity anomaly. This method suppresses information about intermediate and shallow structures while highlighting gravity information about deep structures, enabling the study of deep targets. However, because the amplitude and morphology of surface-observed gravity anomalies vary significantly at different depths for targets of the same size, the amplitude and morphology of the gravity anomaly when the stripping layer has large fluctuations in the depth distribution are poorly correlated with the scale and amplitude of the target structure, severely impacting the effectiveness of this method. Summary of the Invention

[0004] In order to obtain gravity data that can provide more intuitive and accurate reflection of deep stratigraphic structure, in one aspect of the present invention, a layer-flattening gravity anomaly extraction method is proposed, the method comprising: constructing a seismic profile using seismic data of a target area and performing stratigraphic interpretation; determining a layer-flattening reference surface and its depth, the layer-flattening reference surface being a smooth curved surface for determining the deepest stripping surface and the stripping depth of gravity stripping; performing gravity stripping based on the layer-flattening reference surface and its depth to obtain a stripping gravity anomaly with the layer-flattening reference surface as the deepest stripping surface; calculating the regional gravity field of the target area using pre-acquired terrain elevation data, and removing the influence of the regional gravity field on the stripping gravity anomaly to obtain a stripping residual gravity anomaly; performing downward extension processing on the stripping residual gravity anomaly, the downward extension depth being the depth of the layer-flattening reference surface, to obtain the layer-flattening gravity anomaly of the target area.

[0005] In one or more embodiments, determining the layer flattening reference surface and its depth includes: determining a relatively reliable deepest formation interface based on the formation interpretation, and smoothing the relatively reliable deepest formation interface to obtain a smooth curved surface; translating the smooth curved surface as a whole downward until the smooth curved surface no longer intersects with the relatively reliable deepest formation interface to obtain a layer flattening reference surface, and determining the depth of the layer flattening reference surface.

[0006] In one or more embodiments, before using the seismic data of the target area to construct a seismic profile and perform stratigraphic interpretation, the method also includes: gravity data acquisition and anomaly extraction, deploying gravity exploration points in the target area, collecting gravity data to obtain measuring point coordinates, elevation data and gravity values; performing normal field correction, elevation correction, intermediate layer correction and terrain correction calculations to obtain Bouguer gravity anomalies at each measuring point; seismic data acquisition and processing and interpretation, deploying seismic exploration in the target area, collecting seismic data, and obtaining raw seismic data; combining drilling and logging data to perform seismic data processing, inversion and interpretation, obtaining seismic profiles and velocity data of each seismic layer and burial depth data of each stratigraphic interface, and converting the velocity data of each layer into stratigraphic density.

[0007] In one or more embodiments, determining the relatively reliable deepest formation interface includes: analyzing the seismic data and using the relatively reliable deepest formation reflection surface as the relatively reliable deepest formation interface.

[0008] In one or more embodiments, the gravity stripping processing is performed based on the layer leveling reference surface and its depth to obtain the stripping gravity anomaly with the layer leveling reference surface as the deepest stripping surface, including: forward calculating the first model gravity value of all strata between the ground and the layer leveling reference surface based on the stratum depth and stratum density of each stratum located above the layer leveling reference surface; replacing the stratum density located above the layer leveling reference surface with the average density of the basement, and forward calculating the second model gravity value between the ground and the layer leveling reference surface; subtracting the first model gravity value from the Bouguer gravity anomaly, and adding the second model gravity value to obtain the stripping gravity anomaly of the target area with the layer leveling reference surface as the deepest stripping surface.

[0009] In one or more embodiments, the method further includes using any of the following methods to remove the influence of the regional gravity field on the delamination gravity anomaly to obtain the delamination residual gravity anomaly, and any of the methods includes: potential field continuation method, wavenumber domain filtering method or trend analysis method.

[0010] In one or more embodiments, the depth of the layer leveling reference surface is determined relative to the ground.

[0011] In one or more embodiments, the layer-leveling gravity anomaly reflects the stratigraphic structure below the layer-leveling reference surface obtained by taking the layer-leveling reference surface as the observation surface.

[0012] In the second aspect of the present invention, a layer-leveling gravity anomaly extraction device is proposed, comprising: a data input port configured to obtain input data; a data output port configured to output the processing results of the input data; a processing module configured to execute a preset computer program based on the input data and obtain corresponding processing results, wherein the computer program, when executed, is used to implement the corresponding steps of the layer-leveling gravity anomaly extraction method in any of the above embodiments; and a storage module configured to store the input data, the computer program and the processing results.

[0013] In a third aspect of the present invention, a readable storage medium is proposed, in which an executable computer program is stored. When the computer program is executed, it is used to implement the corresponding steps of the layer flattening gravity anomaly extraction method in any of the above embodiments.

[0014] The beneficial effects of the present invention include: first, the present invention determines a layer flattening reference surface and its depth, and uses the layer flattening reference surface as the deepest stripping surface for gravity stripping processing. On the one hand, the gravity information of the middle and shallow layers is removed as much as possible. On the other hand, a relatively smooth layer flattening reference surface is used to replace the relatively reliable deepest stratum interface as the stripping surface for gravity stripping processing, which effectively solves the distortion problem of the stripping gravity anomaly caused by using the relatively reliable deepest stratum interface as the stripping surface when the local fluctuation of the relatively reliable deepest stratum interface is too large; then, the stripping residual gravity anomaly is obtained by removing the influence of the regional gravity field, and the stripping residual gravity anomaly is downwardly extended, so that while enhancing the deep layer information, the middle and shallow layer information and the influence of the gravity field will not be amplified to affect the accuracy of the stripping residual gravity anomaly, so that the layer flattening gravity anomaly obtained by the downward extension method based on the stripping residual gravity anomaly can more intuitively and accurately reflect the stratum structure below the layer flattening reference surface. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other embodiments can be obtained based on these drawings without paying any creative work.

[0016] Figure 1 This is a workflow diagram of the layer-leveling gravity anomaly extraction method of the present invention;

[0017] Figure 2 It is the formation gravity curve diagram of the present invention;

[0018] Figure 3 It is a schematic diagram of the seismic section and stratigraphic interpretation of the present invention;

[0019] Figure 4 Schematic diagram of determining a layer-flattening reference surface M2 based on a peeling surface M1;

[0020] Figure 5 This is a schematic diagram of the stratum structure reflected by the layer-leveling gravity anomaly obtained by the present invention. DETAILED DESCRIPTION

[0021] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the embodiments of the present invention are further described in detail below in conjunction with specific embodiments and with reference to the accompanying drawings.

[0022] It should be noted that all expressions using "first" and "second" in the embodiments of the present invention are for distinguishing two non-identical entities with the same name or non-identical parameters. It can be seen that "first" and "second" are only for the convenience of expression and should not be understood as limitations on the embodiments of the present invention. Subsequent embodiments will not explain this one by one.

[0023] Figure 1 This is a workflow diagram for the layer-flattening gravity anomaly extraction method of the present invention. The layer-flattening gravity anomaly refers to a gravity anomaly reflecting the distribution of deep strata, obtained by combining multiple processing methods such as gravity layer stripping and downward continuation, using the layer-flattening reference surface proposed in this invention as the maximum stripping surface. This anomaly reflects the structure of the strata below the layer-flattening reference surface. To more clearly illustrate the technical solution of the present invention, each step of the method will be described in detail below:

[0024] Step S1: Use the seismic data of the target area to construct a seismic profile and perform stratigraphic interpretation. Before executing step S1, the method of the present invention also requires basic geological exploration work, including: gravity data acquisition and anomaly extraction, deploying gravity exploration points in the target area, and conducting gravity data acquisition to obtain the coordinates of the measuring points, elevation data, and gravity values; performing normal field correction, elevation correction, intermediate layer correction, and terrain correction calculations to obtain the Bouguer gravity anomaly of each measuring point; seismic data acquisition and processing and interpretation, deploying seismic exploration in the target area, conducting seismic data acquisition, and obtaining raw seismic data; combining drilling and logging data to perform seismic data processing, inversion, and interpretation, obtain seismic velocity data of each layer and burial depth data of each layer, and converting the velocity data of each layer into stratigraphic density. Afterwards, the present invention will construct a seismic profile and perform stratigraphic interpretation based on the velocity data and burial depth data of each layer reflected in the seismic data.

[0025] Step S2, determine the layer flattening reference surface and its depth. The layer flattening reference surface is a smooth curved surface, which is used to determine the deepest stripping surface and the maximum stripping depth of the gravity stripping process. The core idea of ​​gravity stripping process is to remove the gravity information of the middle and shallow layers in the gravity information to relatively highlight the gravity information of the deep layers. The purpose of setting the layer flattening reference surface is, on the one hand, to remove the gravity information of the middle and shallow layers as much as possible, and on the other hand, to use the smooth layer flattening reference surface to replace the relatively reliable deepest stratum interface as the maximum stripping surface for gravity stripping process, which effectively solves the problem of distortion of the stripping gravity anomaly caused by excessive local fluctuation of the relatively reliable deepest stratum interface, thereby effectively solving the problem that the obtained stripping gravity anomaly cannot accurately reflect the stratigraphic structure of the deep layer.

[0026] In an optional implementation, the method for determining the layer flattening reference surface and its depth includes determining the relatively reliable deepest stratigraphic interface based on stratigraphic interpretation, and smoothing the relatively reliable deepest stratigraphic interface to obtain a smooth curved surface; translating the smooth curved surface as a whole downward until the smooth curved surface no longer intersects with the relatively reliable deepest stratigraphic interface to obtain the layer flattening reference surface, and determining the depth of the layer flattening reference surface.

[0027] In other optional embodiments, the determination of the layer flattening reference surface can also be established through a function or constructed based on the trend of the relatively reliable deepest formation interface. Of course, whether the layer flattening reference surface is established through a function or constructed based on the trend, it should be ensured that it is smooth, basically parallel and as close as possible to the relatively reliable deepest formation interface, but does not intersect with it.

[0028] In another optional implementation, the method of determining the relatively reliable deepest formation interface includes: analyzing seismic data and using the relatively reliable deepest formation reflection surface as the relatively reliable deepest formation interface.

[0029] Step S3, gravity stripping is performed based on the layer flattening reference surface and its depth to obtain the stripping gravity anomaly with the layer flattening reference surface as the deepest stripping surface. The gravity stripping processing method of the present invention combines the gravity and seismic data of the target area, and forward calculates the first model gravity value of all strata between the ground and the layer flattening reference surface according to the stratum depth and stratum density of each stratum located above the layer flattening reference surface; replaces the stratum density located above the layer flattening reference surface with the average density of the base, and forward calculates the second model gravity value between the ground and the layer flattening reference surface; subtracts the first model gravity value from the Bouguer gravity anomaly, and adds the second model gravity value to obtain the stripping gravity anomaly of the target area with the layer flattening reference surface as the deepest stripping surface. The stripping gravity anomaly obtained in this step S3 is the gravity anomaly of the strata below the layer flattening plane obtained with the ground as the observation point. In order to more intuitively and accurately reflect the stratum structure corresponding to the delamination gravity anomaly, the present invention further adopts step S5 to convert the delamination gravity anomaly observed on the ground into the delamination gravity anomaly equivalent to that observed at a certain depth underground.

[0030] Before performing step S5, step S4 needs to be performed to calculate the regional gravity field of the target area using the pre-acquired terrain elevation data, and remove the influence of the regional gravity field on the delamination gravity anomaly to obtain the delamination residual gravity anomaly;

[0031] In some optional embodiments, any of the following methods is used to remove the influence of the regional gravity field on the delamination gravity anomaly to obtain the delamination residual gravity anomaly, and any of the above methods include: potential field continuation method, wavenumber domain filtering method or trend analysis method.

[0032] Step S5: The stripping residual gravity anomaly is further extended downward to the depth of the layer-flattening reference surface to obtain the layer-flattening gravity anomaly of the target area. Because the present invention has already removed the influence of the mid-shallow layer gravity information and the regional gravity field on the stripping gravity information in steps S3 and S4, the downward extension method used in this step for data enhancement does not amplify the influence of the mid-shallow layer information and the regional gravity field, thus avoiding interference with the deep-layer information obtained—the stripping residual gravity anomaly. As a result, the layer-flattening gravity anomaly obtained by the present invention can more intuitively and accurately reflect the deep-layer structure. It should be noted that the depths herein are all determined relative to the ground.

[0033] In the above embodiments, the present invention first determines a layer flattening reference surface and its depth, and uses the layer flattening reference surface as the deepest stripping surface for gravity stripping processing. On the one hand, it removes the gravity information of the middle and shallow layers as much as possible. On the other hand, it uses a relatively smooth layer flattening reference surface to replace the relatively reliable deepest stratum interface as the deepest stripping surface for gravity stripping processing, which effectively solves the distortion problem of the stripping gravity anomaly caused by using the relatively reliable deepest stratum interface as the stripping surface when the local fluctuation of the relatively reliable deepest stratum interface is too large; then, the stripping residual gravity anomaly is obtained by removing the influence of the regional gravity field, and the stripping residual gravity anomaly is downwardly extended, so that while enhancing the deep layer information, the middle and shallow layer information and the influence of the gravity field will not be amplified to affect the accuracy of the stripping residual gravity anomaly, so that the layer flattening gravity anomaly obtained by the downward extension method based on the stripping residual gravity anomaly can more intuitively and accurately reflect the stratum structure below the layer flattening reference surface. Specific embodiments

[0035] On the basis of the above embodiments, the present invention will hereinafter illustrate the complete implementation process of the layer-leveling gravity anomaly extraction method of the present invention through a more specific embodiment.

[0036] Step 1: Gravity deployment and acquisition. Before conducting gravity exploration in the case study area, geological and geophysical data were first collected to understand the main structural trends in the area. Gravity survey lines were then laid out perpendicular to the main structural trends. Field gravity data acquisition was then carried out to obtain the coordinates, elevations, and gravity values ​​of the gravity measurement points. Simultaneously, data preprocessing was performed, including gravity normal field correction, elevation correction, intermediate layer correction, terrain correction, and other correction calculations to obtain the Bouguer gravity anomaly data G1, see [1]. Figure 2 . Figure 2 This is the formation gravity curve diagram of the present invention. Figure 2In addition to the Bouguer gravity anomaly curve G1, the diagram also shows shallow-layer gravity stripping effect curves G3-G2, stripping gravity anomaly curve G4, stripping residual gravity anomaly curve G6, and layer-leveling gravity anomaly curve G7. G3 is the gravity anomaly curve obtained by replacing the stratum density above the stripping surface with the average density of the basement, and G2 is the gravity anomaly curve obtained by superimposing the various strata above the stripping surface. The layer-leveling gravity anomaly curve G7, obtained by the present invention, can more intuitively and accurately reflect the deep-layer structure.

[0037] Step 2: Seismic data acquisition, processing and interpretation. Deploy seismic exploration in the study area, conduct seismic data acquisition, and obtain raw seismic data; combine drilling and logging data to process, invert and interpret seismic data to obtain seismic profiles and velocity data of each layer and buried depth data of each layer interface. Figure 3 . Figure 3 This is a schematic diagram of the seismic profile and stratum interpretation of the present invention. Figure 3 As shown, there are four stratum interfaces L1 to L4 in the depth map of this embodiment, among which the stratum interfaces L1 and L2 and their corresponding strata are imaged better, while the stratum interfaces L3 and L4 and their corresponding strata are imaged worse.

[0038] Step 3: Determine the deepest relatively reliable stratigraphic interface. By analyzing seismic data and combining seismic profiles, a relatively reliable stratigraphic reflection surface (i.e., stratigraphic interface) is used as the stripping surface for gravity stripping. Since the stratigraphic interfaces L1 and L2 have good imaging and the results are confirmed, they can be used as the stripping surfaces in this example, while L3 has poor imaging and is difficult to use as the stripping surface. L4 is the top surface of the basement and has poor imaging, making it the target layer to be studied. Based on this, stratigraphic interface L2 is used as the deepest relatively reliable stripping stratigraphic interface for research in this target area. Its imaging can be further seen in Figure 4 M1 in. Figure 4 Schematic diagram of determining the layer-flattening reference surface M2 based on the peeling layer M1.

[0039] Step 4: Obtaining the layer flattening reference surface. A layer flattening reference surface is established below the relatively reliable deepest layer interface M1 determined in step S3. The layer flattening reference surface needs to be as smooth as possible and as close to the layer interface M1 as possible without intersecting it. The layer flattening reference surface M2 can be obtained by filtering and smoothing the layer interface M1 and then shifting it downward. The relative positions of the two after the shift are shown in the figure. Figure 4 Of course, the layer flattening reference surface M2 can also be constructed by a function or according to the trend of the deepest stratum interface or similar methods. In the present invention, the layer flattening reference surface is used as the deepest peeling surface.

[0040] Step 5: Combined gravity-seismic stripping. In this example, based on the depths of the stripping planes L1, L2, and M2, as well as through stripping velocity conversion, specimen and lithologic density values, the model gravity curve G2 of all strata between the ground and the layer-leveling reference plane M2 is forward calculated. Based on the depth of the layer-leveling reference plane M2 and the average density value of the basement, the model gravity curve G3 is forward calculated after the density of the strata between the ground and the layer-leveling reference plane M2 is replaced with the average density of the basement. G3-G2 is the gravity stripping effect of the strata above M2, see Figure 2 The G3-G2 curve is obtained by subtracting the model gravity G2 of all strata above the layer-leveling reference surface M2 from the Bouguer gravity anomaly G1, and adding the model gravity G3 when the strata above the layer-leveling reference surface M2 are at the base average density. This gives the delamination gravity anomaly equivalent to when the strata above the layer-leveling reference surface M2 are replaced by the base average density. Figure 2 At this time, the strata above the layer-leveling reference surface M2 and the strata below the basement top surface can be regarded as basement density. The stripping gravity anomaly mainly reflects the stratum structure between the layer-leveling reference surface M2 and the basement top surface L4, as well as the deep regional gravity field, and its observation position is the ground.

[0041] Step 6: Remove the regional gravity field. The regional gravity field can be removed by performing equilibrium gravity correction calculations using terrain elevation data, or by using regional field removal methods such as potential field extension, wavenumber domain filtering, and trend analysis. In this example, the trend analysis method was used to obtain the gravity trend curve G5 (reflecting the impact of the regional gravity field). The delamination residual gravity anomaly curve G6 was obtained by subtracting the gravity trend curve G5 from the delamination gravity anomaly curve G4. Figure 2 At this point, the area above the layer-leveling reference surface M2 and below the basement top surface is considered to be the basement average density. The stripping gravity residual anomaly curve G6 primarily inverts the stratigraphic structure between M2 and the basement top surface, while the gravity measurement point remains on the ground. Due to the large distance between the observation point and the basement top surface, the basement structural features are weak, making basement structural research less intuitive and accurate.

[0042] Step 7: Continue downward to obtain the layer-leveling gravity anomaly. In this example, the downward continuation method is used to continue downward the residual gravity anomaly curve G6 after stripping. The downward continuation depth is the depth of the layer-leveling reference surface, thereby obtaining the gravity anomaly curve G7 that is equivalent to the one observed on the layer-leveling reference surface and mainly reflects the undulating characteristics of the basement top surface L4. Figure 2 .contrast Figure 2 The stripping residual gravity anomaly curve G6, the layer flattening gravity curve G7 and Figure 3It can be seen from the top surface L4 of the basement that the flattened gravity anomaly curve G7 can more intuitively and accurately reflect the location of the fault depression on the top surface L4 of the basement, thereby providing more accurate gravity data. In addition, by further comparing Figure 2 and Figure 3 It can be seen that the interface L1 of the middle and shallow strata is raised at the fault position of the basement top surface L4, which cannot accurately reflect the fault position of the basement top surface L4; and the stripping residual gravity anomaly curve G6 obtained by the existing gravity-seismic combined stripping method, even if the layer pulling plane is used as the maximum stripping surface, is small in amplitude and large in width due to the observation point being on the ground, making it difficult to intuitively and accurately judge the fault position of the basement top surface L4; and after extending the stripping residual gravity anomaly downward to the layer flattening reference surface M2, which is equivalent to setting the gravity observation point on the layer flattening reference surface, the obtained layer flattening gravity anomaly curve G7 can more intuitively and accurately reflect the fault position and shape of the basement top surface L4, thereby enabling the gravity data obtained by the method of the present invention to play a more significant role in studying deep structures. Among them, Figure 5 This is a schematic diagram of the stratum structure reflected by the layer flattening gravity anomaly obtained by the present invention. Figure 5 As shown, the stratum structure reflected by the layer-leveling gravity anomaly of the present invention is between the layer-leveling reference surface M2 and the basement top surface L4.

[0043] Based on the above-mentioned method embodiments, the present invention also proposes a layer-leveling gravity anomaly extraction device, comprising: a data input port, configured to obtain input data; a data output port, configured to output the processing results of the input data; a processing module, configured to execute a preset computer program based on the input data and obtain corresponding processing results, wherein the computer program, when executed, is used to implement the corresponding steps of the layer-leveling gravity anomaly extraction method in any of the above-mentioned method embodiments; and a storage module, configured to store the above-mentioned input data, computer program and processing results.

[0044] Based on the above-mentioned method embodiments, the present invention also proposes a readable storage medium, which stores an executable computer program. When the computer program is executed, it is used to implement the corresponding steps of the layer flattening gravity anomaly extraction method in any of the above-mentioned method embodiments.

[0045] The above are exemplary embodiments disclosed in the present invention, but it should be noted that various changes and modifications may be made without departing from the scope of the embodiments disclosed in the claims. The functions, steps and / or actions of the method claims according to the disclosed embodiments described herein do not need to be performed in any particular order. In addition, although the elements disclosed in the embodiments of the present invention may be described or required in individual form, they may also be understood as multiple unless expressly limited to the singular.

[0046] It should be understood that, as used herein, the singular forms "a" and "an" are intended to include the plural forms as well, unless the context clearly supports an exception. It should also be understood that, as used herein, "and / or" is intended to include any and all possible combinations of one or more of the associated listed items.

[0047] The serial numbers of the embodiments disclosed in the above embodiments of the present invention are only for description and do not represent the advantages or disadvantages of the embodiments.

[0048] Those skilled in the art should understand that the discussion of any of the above embodiments is merely illustrative and is not intended to imply that the scope of the disclosure of the embodiments of the present invention (including the claims) is limited to these examples. Within the spirit of the embodiments of the present invention, the technical features of the above embodiments or different embodiments may be combined, and there are many other variations of different aspects of the above embodiments of the present invention, which are not provided in detail for the sake of simplicity. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the embodiments of the present invention should be included in the scope of protection of the embodiments of the present invention.

Claims

1. A layer-leveling gravity anomaly extraction method, characterized in that: The method comprises: Use seismic data from the target area to construct seismic profiles and perform stratigraphic interpretation; Determining a layer flattening reference surface and its depth, wherein the layer flattening reference surface is a smooth curved surface used to determine the deepest peeling surface and the peeling depth of the gravity peeling process; Performing gravity stripping based on the layer flattening reference surface and its depth to obtain a stripping gravity anomaly with the layer flattening reference surface as the deepest stripping surface; Calculating the regional gravity field of the target area using pre-acquired terrain elevation data, and removing the influence of the regional gravity field on the delamination gravity anomaly to obtain the delamination residual gravity anomaly; The stripping residual gravity anomaly is subjected to downward extension processing, and the downward extension depth is the depth of the layer flattening reference surface, so as to obtain the layer flattening gravity anomaly of the target area.

2. The layer-leveling gravity anomaly extraction method according to claim 1, characterized in that: The determining of the layer-leveling reference surface and its depth includes: Determining a relatively reliable deepest stratum interface based on the stratum interpretation, and smoothing the relatively reliable deepest stratum interface to obtain a smooth curved surface; The smooth curved surface is entirely translated downward until the smooth curved surface no longer intersects the relatively reliable deepest stratum interface to determine the depth of the layer flattening reference surface.

3. The layer-leveling gravity anomaly extraction method according to claim 1, characterized in that: Before constructing a seismic profile using the seismic data of the target area and performing stratigraphic interpretation, the method further includes: Gravity data collection and anomaly analysis: deploying gravity survey points within the target area to collect gravity data to obtain measuring point coordinates, elevation data, and gravity values; Perform normal field correction, elevation correction, intermediate layer correction and terrain correction calculations to obtain the Bouguer gravity anomaly at each measuring point; Seismic data acquisition, processing and interpretation: deploying seismic exploration in the target area, collecting seismic data, and obtaining raw seismic data; Combine drilling and logging data to perform seismic data processing, inversion and interpretation, obtain seismic profiles and velocity data of each seismic layer and buried depth data of each formation interface, and convert the velocity data of each layer into formation density.

4. The layer-leveling gravity anomaly extraction method according to claim 2, characterized in that: The relatively reliable deepest stratum interface is determined as follows: The seismic data are analyzed, and the relatively reliable deepest stratum reflection surface is used as the relatively reliable deepest stratum interface.

5. The layer-leveling gravity anomaly extraction method according to claim 3, characterized in that: The gravity stripping process is performed based on the layer flattening reference surface and its depth to obtain a stripping gravity anomaly with the layer flattening reference surface as the deepest stripping surface, including: forward calculating first model gravity values ​​of all strata between the ground and the layer-leveling reference surface based on the depth and density of each stratum located above the layer-leveling reference surface; replacing the stratum density above the layer-leveling reference surface with the base average density, and forward calculating a second model gravity value between the ground and the layer-leveling reference surface; The Bouguer gravity anomaly is subtracted from the first model gravity value, and then added to the second model gravity value to obtain the stripping gravity anomaly of the target area with the layer flattening reference surface as the deepest stripping surface.

6. The layer-leveling gravity anomaly extraction method according to claim 5, characterized in that: The method further includes removing the influence of the regional gravity field on the delamination gravity anomaly to obtain the delamination residual gravity anomaly by using any of the following methods: potential field continuation method, wavenumber domain filtering method or trend analysis method.

7. The layer-leveling gravity anomaly extraction method according to claim 1, characterized in that: The depth of the layer leveling reference surface is determined relative to the ground.

8. The layer-leveling gravity anomaly extraction method according to claim 1, characterized in that: The layer-leveling gravity anomaly reflects the stratigraphic structure below the layer-leveling reference surface obtained by taking the layer-leveling reference surface as the visual observation surface.

9. A layer-leveling gravity anomaly extraction device, characterized in that: include: Data input port, configured to obtain input data; Data output port, configured to output the processing result of input data; a processing module configured to execute a preset computer program based on the input data and obtain corresponding processing results, wherein the computer program, when executed, is used to implement the corresponding steps of the layer-flattening gravity anomaly extraction method according to any one of claims 1 to 8; as well as A storage module is configured to store the input data, the computer program and the processing result.

10. A readable storage medium, characterized in that: The readable storage medium stores an executable computer program, and when the computer program is executed, it is used to implement the corresponding steps in the layer flattening gravity anomaly extraction method according to any one of claims 1 to 8.

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