A gravity profile forward and inverse inversion method and device

Abstract

The present invention discloses a method and device for forward and inverse gravity profiling. The method includes: constructing an initial model based on the gravity data, existing geological and geophysical results, and density data of the study area; performing forward and inverse residual gravity anomaly profiling on the initial model to obtain a first corrected model; performing forward and inverse gravity horizontal gradient anomaly profiling on the first corrected model to obtain a second corrected model; performing forward and inverse gravity vertical first derivative anomaly profiling on the second corrected model to obtain a third corrected model; returning to perform one or more steps of forward and inverse residual gravity anomaly profiling, forward and inverse gravity horizontal gradient anomaly profiling, and forward and inverse gravity vertical first derivative anomaly profiling on the third corrected model in a loop until the results of forward and inverse residual gravity anomaly profiling, forward and inverse gravity horizontal gradient anomaly profiling, and forward and inverse gravity vertical first derivative anomaly profiling all meet the preset conditions, so as to obtain a final model. The present invention improves the accuracy of forward and inverse gravity profiling.

Description

Technical Field

[0001] The present invention relates to the technical field of gravity exploration, and in particular to a method and device for forward and inverse gravity profiling. Background Art

[0002] Gravity exploration is a geophysical exploration method that collects gravity data using a gravimeter, calculates the Bouguer gravity anomaly through data calculation, and then obtains the underground geological structure and the distribution of minerals and resources through data processing, inversion, and geological interpretation. Gravity data collection and calculation of the Bouguer gravity anomaly are the basis of gravity exploration. The purpose of gravity data processing is to extract the gravity anomaly containing specific geological information to provide a basis for geological interpretation. Gravity inversion is to obtain the geometric characteristics and density distribution of underground geological bodies or structures through forward and inverse calculations to provide information for geological research and exploration and development of energy resources. It can be seen that gravity inversion plays a very important role in gravity exploration. Gravity inversion includes profile forward and inverse inversion and plane inversion, etc. The technology of the present invention relates to the profile forward and inverse inversion of gravity data.

[0003] The existing gravity profile forward and inverse inversion technology is to establish an initial geological and density model based on the obtained geological and geophysical data, and obtain a geological model as close as possible to the real geological situation through gravity forward and inverse calculations. In gravity profile forward and inverse inversion, the gravity data used is the Bouguer gravity anomaly or the residual gravity anomaly. Since the gravity anomaly is the comprehensive reflection of all underground density bodies on the ground, multiple geological models can produce similar gravity effects, resulting in strong non-uniqueness of gravity inversion. At the same time, due to the insensitivity of the Bouguer gravity anomaly or the residual gravity anomaly to changes in the geological model, the accuracy of gravity exploration is relatively low. How to obtain higher-precision gravity forward and inverse inversion results has always been the goal pursued by gravity workers.

[0004] To improve the accuracy of gravity profile forward and inverse inversion, researchers have developed a variety of gravity profile forward and inverse inversion technologies. One is to introduce known reliable data (such as surface geology, drilling, seismic, electromagnetic data, etc.) into the initial geological model, and improve the gravity inversion accuracy through constrained inversion. This method improves the overall inversion accuracy, especially the inversion accuracy near the constraint points, but the accuracy at positions far from the constraint points cannot be guaranteed. Moreover, in the gravity exploration stage, there are generally few reliable known data, making the potential for improving the inversion accuracy limited. The other is the model forward selection method, which establishes multiple possible models by combining other known data, and uses the model with good forward fitting effect as the final inversion result. However, due to the equivalence of gravity, the model forward selection method is limited by the established initial model and cannot guarantee the correctness of the inversion result. Therefore, gravity workers have been looking for new gravity forward and inverse inversion methods, hoping to greatly improve the accuracy of gravity profile forward and inverse inversion. Summary of the Invention

[0005] In view of this, the present invention provides a forward and inverse gravity profile method and device, which solves the problem of low accuracy in the traditional forward and inverse gravity profile, improves the effect of gravity exploration, and enables gravity exploration to play a greater role.

[0006] Based on the above object, on the one hand, an embodiment of the present invention provides a forward and inverse gravity profile method, which specifically includes the following steps:

[0007] Construct an initial model based on the gravity data of the study area, existing geological and geophysical exploration results, and density data;

[0008] Perform forward and inverse residual gravity anomaly profile on the initial model to obtain a first corrected model;

[0009] Perform forward and inverse gravity horizontal gradient anomaly profile on the first corrected model to obtain a second corrected model;

[0010] Perform forward and inverse gravity vertical first derivative anomaly profile on the second corrected model to obtain a third corrected model;

[0011] Return to perform one or more steps of the forward and inverse residual gravity anomaly profile, forward and inverse gravity horizontal gradient anomaly profile, and forward and inverse gravity vertical first derivative anomaly profile on the third corrected model in a loop until the results of the forward and inverse residual gravity anomaly profile, forward and inverse gravity horizontal gradient anomaly profile, and forward and inverse gravity vertical first derivative anomaly profile all meet the preset conditions, and obtain the final model.

[0012] In some embodiments, constructing an initial model based on the gravity data of the study area, existing geological and geophysical exploration results, and density data includes:

[0013] Obtain Bouguer gravity anomaly data based on the gravity data;

[0014] Obtain the measured residual gravity anomaly based on the Bouguer gravity anomaly data and the topography of the study area;

[0015] Construct an initial model based on the measured residual gravity anomaly, existing geological and geophysical exploration results, and density data.

[0016] In some embodiments, the method further includes:

[0017] Calculate the horizontal gradient modulus and vertical first derivative of the measured residual gravity anomaly respectively to obtain the measured gravity horizontal gradient anomaly and the measured gravity vertical first derivative anomaly.

[0018] In some embodiments, performing forward and inverse residual gravity anomaly profile on the initial model to obtain a first corrected model includes:

[0019] Perform gravity forward modeling on the initial model to obtain the gravity anomaly of the initial model;

[0020] Perform fitting comparison on the gravity anomaly of the initial model and the measured residual gravity anomaly;

[0021] Modify the initial model based on the fitting comparison between the gravity anomaly of the initial model and the measured residual gravity anomaly to obtain the first corrected model.

[0022] In some embodiments, modifying the initial model based on the fitting comparison between the gravity anomaly of the initial model and the measured residual gravity anomaly to obtain the first corrected model includes:

[0023] Modify the initial model based on the fitting comparison between the gravity anomaly of the initial model and the measured residual gravity anomaly to obtain the first initial corrected model;

[0024] Perform gravity forward modeling on the first initial corrected model to obtain the gravity anomaly of the first initial corrected model;

[0025] Perform fitting comparison on the gravity anomaly of the first initial corrected model and the measured gravity anomaly;

[0026] If the fitting comparison between the gravity anomaly of the first initial corrected model and the measured gravity anomaly does not meet the preset condition, modify the first initial corrected model and return to the step of performing gravity forward modeling on the modified model until the fitting comparison between the gravity anomaly of the modified model and the measured gravity anomaly meets the preset condition to obtain the final first corrected model.

[0027] In some embodiments, the method further includes:

[0028] If the fitting comparison between the gravity anomaly of the first initial corrected model and the measured gravity anomaly meets the preset condition, determine the first initial corrected model as the final first corrected model.

[0029] In some embodiments, performing forward and inverse modeling of the gravity horizontal gradient anomaly profile on the first corrected model to obtain the second corrected model includes:

[0030] Perform gravity horizontal gradient forward modeling on the first corrected model to obtain the gravity horizontal gradient anomaly of the first corrected model;

[0031] Perform fitting comparison on the gravity horizontal gradient anomaly of the first corrected model and the measured gravity horizontal gradient anomaly;

[0032] Modify the first correction model based on the fitting comparison between the gravity horizontal gradient anomaly of the first correction model and the measured gravity horizontal gradient anomaly to obtain the second correction model.

[0033] In some embodiments, modifying the first correction model based on the fitting comparison between the gravity horizontal gradient anomaly of the first correction model and the measured gravity horizontal gradient anomaly to obtain the second correction model includes:

[0034] Modify the first correction model based on the fitting comparison between the gravity horizontal gradient anomaly of the first correction model and the measured gravity horizontal gradient anomaly to obtain a second initial correction model;

[0035] Perform a forward calculation of the gravity horizontal gradient on the second initial correction model to obtain the gravity horizontal gradient anomaly of the second initial correction model;

[0036] Perform a fitting comparison between the gravity horizontal gradient anomaly of the second initial correction model and the measured gravity horizontal gradient anomaly;

[0037] If the fitting comparison between the gravity horizontal gradient anomaly of the second initial correction model and the measured gravity horizontal gradient anomaly does not meet the preset conditions, modify the second initial correction model and return to the step of performing a forward calculation of the gravity horizontal gradient on the modified model until the fitting comparison between the gravity horizontal gradient anomaly of the modified model and the measured gravity horizontal gradient anomaly meets the preset conditions to obtain the final second correction model.

[0038] In some embodiments, the method further includes:

[0039] If the fitting comparison between the gravity horizontal gradient anomaly of the second initial correction model and the measured gravity horizontal gradient anomaly meets the preset conditions, determine the second initial correction model as the final second correction model.

[0040] In some embodiments, performing a forward and inverse calculation of the gravity vertical first derivative anomaly profile on the second correction model to obtain a third correction model includes:

[0041] Perform a forward calculation of the gravity vertical first derivative on the second correction model to obtain the gravity vertical first derivative anomaly of the second correction model;

[0042] Perform a fitting comparison between the gravity vertical first derivative anomaly of the second correction model and the measured gravity vertical first derivative anomaly;

[0043] Modify the second correction model based on the fitting comparison between the gravity vertical first derivative anomaly of the second correction model and the measured gravity vertical first derivative anomaly to obtain a third correction model.

[0044] In some embodiments, the second correction model is modified based on the fitting comparison between the vertical first derivative anomaly of gravity of the second correction model and the measured vertical first derivative anomaly of gravity to obtain a third correction model, including:

[0045] The second correction model is modified based on the fitting comparison between the vertical first derivative anomaly of gravity of the second correction model and the measured vertical first derivative anomaly of gravity to obtain a third initial correction model;

[0046] Forward calculation of the vertical first derivative of gravity is performed on the third initial correction model to obtain the vertical first derivative anomaly of gravity of the third initial correction model;

[0047] Fitting comparison is made between the vertical first derivative anomaly of gravity of the third initial correction model and the measured vertical first derivative anomaly of gravity;

[0048] If the fitting comparison between the vertical first derivative anomaly of gravity of the third initial correction model and the measured vertical first derivative anomaly of gravity does not meet the preset conditions, the third initial correction model is modified and the step of performing forward calculation of the vertical first derivative of gravity on the modified model is returned until the fitting comparison between the vertical first derivative anomaly of gravity of the modified model and the measured vertical first derivative anomaly of gravity meets the preset conditions, and a final third correction model is obtained.

[0049] In some embodiments, the method further includes:

[0050] If the fitting comparison between the vertical first derivative anomaly of gravity of the third initial correction model and the measured vertical first derivative anomaly of gravity meets the preset conditions, the third initial correction model is determined as the final third correction model.

[0051] On the other hand, an embodiment of the present invention further provides a gravity profile forward and inverse modeling device, including:

[0052] A construction module configured to construct an initial model based on the gravity data of the study area, existing geological and geophysical exploration results, and density data;

[0053] A first correction module configured to perform forward and inverse modeling of the residual gravity anomaly profile on the initial model to obtain a first correction model;

[0054] A second correction module configured to perform forward and inverse modeling of the gravity horizontal gradient anomaly profile on the first correction model to obtain a second correction model;

[0055] A third correction module, configured to perform forward and inverse modeling of the gravity vertical first derivative anomaly profile on the second correction model to obtain a third correction model;

[0056] A loop correction module, configured to return to perform one or more steps of forward and inverse modeling of the remaining gravity anomaly profile, forward and inverse modeling of the gravity horizontal gradient anomaly profile, and forward and inverse modeling of the gravity vertical first derivative anomaly profile on the third correction model in a loop until the results of forward and inverse modeling of the remaining gravity anomaly profile, forward and inverse modeling of the gravity horizontal gradient anomaly profile, and forward and inverse modeling of the gravity vertical first derivative anomaly profile all meet preset conditions, to obtain a final model.

[0057] The present invention has at least the following beneficial technical effects: By constructing an initial model; performing forward and inverse modeling of the remaining gravity anomaly profile on the initial model to obtain a first correction model; performing forward and inverse modeling of the gravity horizontal gradient anomaly profile on the first correction model to obtain a second correction model; performing forward and inverse modeling of the gravity vertical first derivative anomaly profile on the second correction model to obtain a third correction model; returning to perform one or more steps of forward and inverse modeling of the remaining gravity anomaly profile, forward and inverse modeling of the gravity horizontal gradient anomaly profile, and forward and inverse modeling of the gravity vertical first derivative anomaly profile on the third correction model in a loop until the results of forward and inverse modeling of the remaining gravity anomaly profile, forward and inverse modeling of the gravity horizontal gradient anomaly profile, and forward and inverse modeling of the gravity vertical first derivative anomaly profile all meet preset conditions, to obtain a final model, the accuracy of gravity profile forward and inverse modeling is improved. Description of the Drawings

[0058] 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 following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, other embodiments can be obtained based on these drawings without creative efforts.

[0059] Figure 1 It is a block diagram of an embodiment of the gravity profile forward and inverse modeling method provided by the present invention;

[0060] Figure 2 It is a graph of the measured remaining gravity anomaly provided by the present invention;

[0061] Figure 3 It is a graph of the initial geological-density model provided by the present invention;

[0062] Figure 4 It is a graph of the measured gravity horizontal gradient anomaly provided by the present invention;

[0063] Figure 5 It is a graph of the measured gravity vertical first derivative anomaly provided by the present invention;

[0064] Figure 6 Schematic diagram of an embodiment of the gravity profile forward and inverse inversion device provided by the present invention. Specific embodiments

[0065] To make the objectives, technical solutions, and advantages of the present invention clearer and more understandable, the following further elaborates on the embodiments of the present invention in detail with reference to specific embodiments and the accompanying drawings.

[0066] It should be noted that all the expressions using "first" and "second" in the embodiments of the present invention are used to distinguish two entities or parameters with the same name but different nature. It can be seen that "first" and "second" are only for the convenience of expression and should not be construed as limitations on the embodiments of the present invention. This will not be elaborated one by one in the subsequent embodiments.

[0067] Based on the above objectives, in the first aspect of the embodiments of the present invention, an embodiment of a gravity profile forward and inverse inversion method is proposed. As Figure 1 shown, it includes the following steps:

[0068] S101. Construct an initial model based on the gravity data of the study area, existing geological and geophysical exploration results, and density data;

[0069] S103. Perform forward and inverse inversion of the residual gravity anomaly profile for the initial model to obtain a first corrected model;

[0070] S105. Perform forward and inverse inversion of the gravity horizontal gradient anomaly profile for the first corrected model to obtain a second corrected model;

[0071] S107. Perform forward and inverse inversion of the gravity vertical first derivative anomaly profile for the second corrected model to obtain a third corrected model;

[0072] S109. Return to perform one or more of the steps of forward and inverse inversion of the residual gravity anomaly profile, forward and inverse inversion of the gravity horizontal gradient anomaly profile, and forward and inverse inversion of the gravity vertical first derivative anomaly profile for the third corrected model in a loop until the results of the forward and inverse inversion of the residual gravity anomaly profile, forward and inverse inversion of the gravity horizontal gradient anomaly profile, and forward and inverse inversion of the gravity vertical first derivative anomaly profile all meet the preset conditions to obtain the final model.

[0073] Collect and analyze existing geological and geophysical exploration results and density data, analyze the characteristics of the measured gravity anomaly, and construct an initial geological-density model M0 according to the gravity principle and geological theory.

[0074] Perform forward and inverse inversion of the residual gravity anomaly profile for the model M0, and adjust the formation distribution, burial depth, thickness, etc. in combination with geological laws to obtain a first corrected model M1.

[0075] Perform forward and inverse modeling of the gravity horizontal gradient anomaly profile for model M1. According to the forward modeling results of the gravity horizontal gradient anomaly profile, adjust the horizontal position, dip angle, and faulted strata of the model boundary or fault, etc., to obtain the second corrected model M2. After carrying out the forward and inverse modeling of the profile based on the residual gravity anomaly, then conduct the forward and inverse gravity modeling based on the gravity horizontal gradient, so that after the geological model reflects the basic geological structure, the position, depth, dip angle, faulted strata, etc. of the model boundary or fault are further optimized, and the fineness of the lateral boundary of model M2 is improved compared to model M1.

[0076] Perform forward and inverse modeling of the gravity vertical first derivative anomaly profile for model M2. According to the forward modeling results of the gravity vertical first derivative anomaly profile, adjust the planar position, undulation change, and morphology of the local structure, etc., to obtain the third corrected model M3. Model M3 is obtained by carrying out the forward and inverse modeling of the profile based on the residual gravity anomaly and the gravity horizontal gradient anomaly profile, and then conducting the forward and inverse gravity modeling based on the gravity vertical first derivative anomaly. Compared with model M2, on the basis of reflecting the basic geological structure and finely reflecting the tectonic boundary or fault, the local structure of model M3 is refined and optimized, the accuracy of model M3 is further improved, and the detailed features of the model are more abundant.

[0077] After obtaining model M3, return to the step of forward and inverse modeling of the residual gravity anomaly profile for model M3, and cyclically perform one or more steps among the forward and inverse modeling of the residual gravity anomaly profile, the forward and inverse modeling of the gravity horizontal gradient anomaly profile, and the forward and inverse modeling of the gravity vertical first derivative anomaly profile until the forward modeling results of the three gravity anomalies of the model meet the requirements, and obtain the final model M4 of the joint forward and inverse modeling of the gravity profile, thus realizing the joint profile cyclic forward and inverse modeling of the three gravity anomalies. During the cyclic forward and inverse modeling process, according to the forward and inverse modeling results of the three anomalies, one or more of the forward and inverse modeling of the residual gravity anomaly profile, the forward and inverse modeling of the gravity horizontal gradient anomaly profile, and the forward and inverse modeling of the gravity vertical first derivative anomaly profile can be selectively performed, not limited to cyclically performing in the order of the forward and inverse modeling of the residual gravity anomaly profile, the forward and inverse modeling of the gravity horizontal gradient anomaly profile, and the forward and inverse modeling of the gravity vertical first derivative anomaly profile. Or if the forward and inverse modeling results of a certain gravity anomaly meet the requirements during a certain cycle, then the profile forward and inverse modeling of this anomaly can not be performed during this cycle, but only the profile forward and inverse modeling of other gravity anomalies is cyclically performed.

[0078] The solution of the present invention improves the accuracy of the forward and inverse modeling of the gravity profile. Without adding new other geophysical exploration and geological data, compared with the existing forward and inverse modeling methods of the gravity profile, the obtained geological model has higher accuracy, has more refined and accurate tectonic and fault characteristics, makes the gravity exploration method further move towards refinement, and plays a greater role for gravity exploration.

[0079] In some embodiments, an initial model is constructed based on the gravity data of the study area, existing geological and geophysical exploration results, and density data, including:

[0080] Obtain Bouguer gravity anomaly data based on the gravity data;

[0081] Obtain the measured residual gravity anomaly based on the Bouguer gravity anomaly data and the topography of the study area;

[0082] Construct an initial model based on the measured residual gravity anomaly, existing geological and geophysical exploration results, and density data.

[0083] Before carrying out gravity exploration in an area (study area), it is necessary to collect geological and geophysical exploration data first, understand the main tectonic trends in the area, and generally arrange gravity survey lines perpendicular or basically perpendicular to the main tectonic trends; then carry out field gravity data acquisition work to obtain the coordinates, elevations, and gravity values of gravity measurement points; at the same time, carry out data preprocessing work, and perform various correction calculations such as gravity normal field correction, elevation correction, intermediate layer correction, and topographic correction to obtain Bouguer gravity anomaly data.

[0084] Since the Bouguer gravity anomaly in some areas contains the trend gravity anomaly generated by the Moho undulation, it is necessary to carry out regional field correction to obtain the residual gravity anomaly reflecting the basin or other research targets. For areas where it is analyzed that there is an influence of Moho undulation, isostatic gravity correction can be carried out using topographic elevation data to obtain the isostatic residual gravity anomaly; for areas where isostatic gravity anomaly correction is not suitable, regional field removal or residual field extraction means such as potential field continuation method, wavenumber domain filtering method, and trend analysis method can be used to extract the residual gravity anomaly from the Bouguer gravity anomaly; for areas where it is analyzed that there is no obvious regional field in the Bouguer gravity anomaly, the Bouguer gravity anomaly is regarded as the residual gravity anomaly. In this embodiment, the above three types of gravity anomalies are collectively referred to as the residual gravity anomaly.

[0085] This embodiment assumes that there is no regional background field in the study area, so there is no need to calculate the residual gravity anomaly, and the Bouguer gravity anomaly data is used as the measured residual gravity anomaly. The measured residual gravity anomaly is as Figure 2 shown, Figure 2 where the unit of the abscissa is m, and the unit of the ordinate is 10 -5 m·s -2 .

[0086] This example establishes a model according to the characteristics of the residual gravity anomaly. By analyzing as Figure 2From the measured residual gravity anomaly characteristics shown, the area mainly includes a gravity low, which is a reflection of the sedimentary depression; at the left boundary of the gravity low, the gravity value rises slowly to the left, and at the right boundary, the gravity value rises rapidly to the right, indicating that the dip angle of the left boundary of the depression is relatively gentle, and the dip angle of the right boundary is relatively steep; there is a gravity high with a low amplitude in the middle of the depression, indicating that there is a small-scale local uplift in the middle of the depression, but its scope and height are difficult to determine. Based on this, an initial geological-density model of the depression can be established. The left boundary of this depression has a gentle dip angle, the right boundary has a steep dip angle, and the positions of both boundaries are in the middle of the area where the gravity value changes rapidly; at the same time, a small-step model is set in the middle of the depression, and its scope and height are temporarily given a certain assumed initial value; the depression density value is generally set according to the collected density data, and here it is temporarily given as -0.2 g / cm 3 . Thus, the initial geological-density model M0 as shown in Figure 3 is established. In Figure 3 , the horizontal and vertical coordinate units are m.

[0087] In some embodiments, the method further includes:

[0088] Performing horizontal gradient modulus calculation and vertical first derivative calculation on the measured residual gravity anomaly respectively to obtain the measured gravity horizontal gradient anomaly and the measured gravity vertical first derivative anomaly.

[0089] Performing horizontal gradient modulus and vertical first derivative calculations on the measured residual gravity anomaly respectively, and obtaining the measured gravity horizontal gradient anomaly as shown in Figure 4 and the measured gravity vertical first derivative anomaly as shown in Figure 5 . Among them, Figure 4 the horizontal coordinate unit in -8 s -2 , Figure 5 the horizontal coordinate unit in -8 s -2 .

[0090] In some embodiments, performing forward and inverse modeling of the residual gravity anomaly profile on the initial model to obtain the first corrected model includes:

[0091] Performing gravity forward calculation on the initial model to obtain the gravity anomaly of the initial model;

[0092] Performing fitting comparison between the gravity anomaly of the initial model and the measured residual gravity anomaly;

[0093] Modifying the initial model based on the fitting comparison between the gravity anomaly of the initial model and the measured residual gravity anomaly to obtain the first corrected model.

[0094] In some embodiments, modifying the initial model based on the fitting comparison between the gravity anomaly of the initial model and the measured residual gravity anomaly to obtain the first corrected model includes:

[0095] Modifying the initial model based on the fitting comparison between the gravity anomaly of the initial model and the measured residual gravity anomaly to obtain a first initial corrected model;

[0096] Performing gravity forward calculation on the first initial corrected model to obtain the gravity anomaly of the first initial corrected model;

[0097] Performing a fitting comparison between the gravity anomaly of the first initial corrected model and the measured gravity anomaly;

[0098] If the fitting comparison between the gravity anomaly of the first initial corrected model and the measured gravity anomaly does not meet the preset conditions, modifying the first initial corrected model and returning to the step of performing gravity forward calculation on the modified model until the fitting comparison between the gravity anomaly of the modified model and the measured gravity anomaly meets the preset conditions to obtain the final first corrected model.

[0099] In some embodiments, the method further includes:

[0100] If the fitting comparison between the gravity anomaly of the first initial corrected model and the measured gravity anomaly meets the preset conditions, determining the first initial corrected model as the final first corrected model.

[0101] Performing gravity forward calculation on the established initial geological-density model M0 to obtain the gravity anomaly Gm of model M0; then comparing the residual gravity anomaly Gm of model M0 with the measured residual gravity anomaly as shown in Figure 2 Adjust the boundary position, dip angle, and sag depth of the sag model M0, and adjust the range and height of the small central step, etc. according to the principle of adjusting where the fitting difference is large, and obtain a new model M1. Then repeatedly perform model forward calculation, fitting situation analysis, and adjustment of model M1 until the forward gravity anomaly of model M1 and the measured residual gravity anomaly are basically fitted. At this time, a geological-density model M1 updated by the forward and inverse of the residual gravity anomaly profile is formed, and this model will be closer to the actual geological situation than the initial model M0.

[0102] In some embodiments, performing forward and inverse of the gravity horizontal gradient anomaly profile on the first corrected model to obtain a second corrected model includes:

[0103] Performing gravity horizontal gradient forward calculation on the first corrected model to obtain the gravity horizontal gradient anomaly of the first corrected model;

[0104] Perform fitting comparison between the gravity horizontal gradient anomaly of the first correction model and the measured gravity horizontal gradient anomaly;

[0105] Modify the first correction model based on the fitting comparison between the gravity horizontal gradient anomaly of the first correction model and the measured gravity horizontal gradient anomaly to obtain the second correction model.

[0106] In some embodiments, modifying the first correction model based on the fitting comparison between the gravity horizontal gradient anomaly of the first correction model and the measured gravity horizontal gradient anomaly to obtain the second correction model includes:

[0107] Modify the first correction model based on the fitting comparison between the gravity horizontal gradient anomaly of the first correction model and the measured gravity horizontal gradient anomaly to obtain a second initial correction model;

[0108] Perform forward calculation of the gravity horizontal gradient on the second initial correction model to obtain the gravity horizontal gradient anomaly of the second initial correction model;

[0109] Perform fitting comparison between the gravity horizontal gradient anomaly of the second initial correction model and the measured gravity horizontal gradient anomaly;

[0110] If the fitting comparison between the gravity horizontal gradient anomaly of the second initial correction model and the measured gravity horizontal gradient anomaly does not meet the preset conditions, modify the second initial correction model and return to the step of performing forward calculation of the gravity horizontal gradient on the modified model until the fitting comparison between the gravity horizontal gradient anomaly of the modified model and the measured gravity horizontal gradient anomaly meets the preset conditions to obtain the final second correction model.

[0111] In some embodiments, the method further includes:

[0112] If the fitting comparison between the gravity horizontal gradient anomaly of the second initial correction model and the measured gravity horizontal gradient anomaly meets the preset conditions, determine the second initial correction model as the final second correction model.

[0113] Perform forward calculation of the gravity horizontal gradient on model M1 to obtain the gravity horizontal gradient anomaly Gxm of model M1; compare the gravity horizontal gradient anomaly Gxm of model M1 and as Figure 4The measured gravity horizontal gradient anomaly shown is used to adjust the boundary position and dip angle of the depression, the boundary of the small middle step, etc. according to the fitting difference situation, and the model M2 is obtained; the forward calculation of the gravity horizontal gradient of the model, the analysis of the fitting situation and the adjustment of the model M2 are repeatedly carried out until the gravity horizontal gradient anomaly Gxm of the model M2 is basically fitted with the measured gravity horizontal gradient anomaly. Since the position of the maximum value of the gravity horizontal gradient anomaly more accurately reflects the fracture position and its shape reflects the dip and dip angle of the fracture, the forward and inverse modeling of the gravity horizontal gradient profile can more accurately optimize the boundary position and dip angle of the depression. At the same time, as can be seen from the measured gravity horizontal gradient anomaly shown in Figure 4 it can be seen that there is a maximum value of the gravity horizontal gradient at the positions of -1000m and 1000 respectively. Therefore, the boundary of the small middle step in the depression can be more accurately determined through the forward and inverse modeling of the gravity horizontal gradient profile. At this time, the model is updated to the model M2 optimized by the forward and inverse modeling of the residual gravity anomaly profile and the gravity horizontal gradient profile, and this model will be closer to the actual situation than the model M1 updated only by the forward and inverse modeling of the residual gravity anomaly profile and the original model M0.

[0114] In some embodiments, forward and inverse modeling of the gravity vertical first derivative anomaly profile of the second correction model is performed to obtain a third correction model, including:

[0115] Perform forward calculation of the gravity vertical first derivative of the second correction model to obtain the gravity vertical first derivative anomaly of the second correction model;

[0116] Perform fitting comparison between the gravity vertical first derivative anomaly of the second correction model and the measured gravity vertical first derivative anomaly;

[0117] Modify the second correction model based on the fitting comparison between the gravity vertical first derivative anomaly of the second correction model and the measured gravity vertical first derivative anomaly to obtain a third correction model.

[0118] In some embodiments, modifying the second correction model based on the fitting comparison between the gravity vertical first derivative anomaly of the second correction model and the measured gravity vertical first derivative anomaly to obtain a third correction model includes:

[0119] Modify the second correction model based on the fitting comparison between the gravity vertical first derivative anomaly of the second correction model and the measured gravity vertical first derivative anomaly to obtain a third initial correction model;

[0120] Perform forward calculation of the gravity vertical first derivative of the third initial correction model to obtain the gravity vertical first derivative anomaly of the third initial correction model;

[0121] Perform fitting comparison between the vertical first derivative anomaly of gravity of the third initial correction model and the measured vertical first derivative anomaly of gravity;

[0122] If the fitting comparison between the vertical first derivative anomaly of gravity of the third initial correction model and the measured vertical first derivative anomaly of gravity does not meet the preset conditions, modify the third initial correction model and return to the step of performing forward calculation of the vertical first derivative of gravity on the modified model until the fitting comparison between the vertical first derivative anomaly of gravity of the modified model and the measured vertical first derivative anomaly of gravity meets the preset conditions, and obtain the final third correction model.

[0123] In some embodiments, the method further includes:

[0124] If the fitting comparison between the vertical first derivative anomaly of gravity of the third initial correction model and the measured vertical first derivative anomaly of gravity meets the preset conditions, determine the third initial correction model as the final third correction model. Perform forward calculation of the vertical first derivative anomaly of gravity on model M2 to obtain the vertical first derivative anomaly of gravity Gzm of model M2; compare the vertical first derivative anomaly of gravity Gzm of model M2 with the measured vertical first derivative anomaly of gravity as shown in Figure 5 According to the fitting difference situation, make a local adjustment to the model to obtain model M3; then repeatedly perform forward calculation of the vertical first derivative anomaly of gravity of the model, fitting situation analysis, and adjustment of model M3 until the vertical first derivative anomaly of gravity of the model and the measured vertical first derivative anomaly of gravity are basically fitted. Since the vertical first derivative of gravity is more sensitive to local structures than the residual gravity anomaly, the profile forward and inverse modeling of the vertical first derivative of gravity will make the model more refined, especially making the height of the small steps in the middle of the depression better determined after the forward and inverse modeling of the horizontal gradient anomaly of gravity. At this time, the entire model is updated to model M3 updated by the forward and inverse modeling of the residual gravity anomaly profile, the forward and inverse modeling of the horizontal gradient anomaly of gravity profile, and the forward and inverse modeling of the vertical first derivative anomaly of gravity profile, which is closer to the actual situation than model M1 updated only by the forward and inverse modeling of the residual gravity anomaly profile and the original model M0.

[0125] In some embodiments, return to perform one or more of the steps of the forward and inverse modeling of the residual gravity anomaly profile, the forward and inverse modeling of the horizontal gradient anomaly of gravity profile, and the forward and inverse modeling of the vertical first derivative anomaly of gravity profile on the third correction model in a loop until the results of the forward and inverse modeling of the residual gravity anomaly profile, the forward and inverse modeling of the horizontal gradient anomaly of gravity profile, and the forward and inverse modeling of the vertical first derivative anomaly of gravity profile all meet the preset conditions to obtain the final model, which specifically includes the following steps:

[0126] S201. Perform forward calculation of gravity on model M3;

[0127] S202. If the gravity forward modeling result of model M3 meets the preset condition, then jump to step S204 to perform gravity horizontal gradient forward modeling on model M3;

[0128] S203. If the gravity forward modeling result of model M3 does not meet the preset condition, then adjust model M3 to obtain model M3-1, and return to step S201 to perform gravity forward modeling on model M3-1 until the gravity forward modeling result of the model meets the preset condition, obtaining model M3-n, where n represents the number of times of returning to step S201;

[0129] S204. Perform gravity horizontal gradient forward modeling on model M3-n;

[0130] S205. If the gravity horizontal gradient forward modeling result of M3-n meets the preset condition, then jump to step S207 to perform gravity vertical first derivative anomaly forward modeling on model M3-n;

[0131] S206. If the gravity horizontal gradient forward modeling result of M3-n does not meet the preset condition, adjust model M3-n to obtain model M3-n-1, and return to step S204 to perform gravity horizontal gradient forward modeling on model M3-n-1 until the gravity horizontal gradient forward modeling result of the model meets the preset condition, obtaining model M3-n-m, where m represents the number of times of returning to step S204;

[0132] S207. Perform gravity vertical first derivative anomaly forward modeling on model M3-n-m;

[0133] S208. If the gravity vertical first derivative anomaly forward modeling result of the adjusted model M3-n-m meets the preset condition, then determine M3-n-m as the final model M4;

[0134] S209. If the gravity vertical first derivative anomaly forward modeling result of the adjusted model M3-n-m does not meet the preset condition, then perform gravity vertical first derivative anomaly forward modeling on M3-n-m to obtain M3-n-m-1, and return to step S207 to perform gravity vertical first derivative anomaly forward modeling on model M3-n-m-1 until the gravity vertical first derivative anomaly forward modeling result of the model meets the preset condition, obtaining model M3-n-m-o, where o represents the number of times of returning to step S207;

[0135] S210. Return to step S201 to perform gravity forward modeling on model M3-n-m-o until the models obtained in a certain time all meet the results of gravity forward modeling, gravity horizontal gradient forward modeling, and gravity vertical first derivative anomaly forward modeling, then determine this model as the final model M4.

[0136] Perform forward and inverse modeling of the residual gravity anomaly profile, the horizontal gravity gradient profile, and the first vertical derivative of gravity profile for the loop of model M3. During the loop of forward and inverse modeling, according to the fitting comparison between the model gravity anomaly indexes obtained from the forward calculations of the three gravity anomalies respectively and the corresponding measured gravity anomaly indexes, one or more of the steps of forward and inverse modeling of the residual gravity anomaly profile, the horizontal gravity gradient profile, and the first vertical derivative of gravity profile can be selectively carried out, not limited to strictly cycling in the order of forward and inverse modeling of the residual gravity anomaly profile, the horizontal gravity gradient anomaly profile, and the first vertical derivative of gravity anomaly profile. Or if the forward and inverse modeling results of a certain gravity anomaly meet the requirements in a certain loop, the profile forward and inverse modeling of this anomaly can be not carried out in this loop, and only the profile forward and inverse modeling of other gravity anomalies is cycled. Until the three gravity anomalies of the forward and inverse modeling model are all fitted to the maximum extent with the three measured gravity anomalies, at this time, the model M4 optimized by the joint profile forward and inverse modeling of the three anomalies is obtained, and the joint profile forward and inverse modeling of the three gravity anomalies is realized. Compared with the model M3, the joint forward and inverse modeling model M4 has higher accuracy, richer details, has more refined and accurate structural and fracture characteristics, and is closer to the actual situation.

[0137] Based on the same inventive concept, according to another aspect of the present invention, as Figure 6 shown, an embodiment of the present invention further provides a gravity profile forward and inverse modeling device, including:

[0138] A construction module 610, configured to construct an initial model based on the gravity data of the study area, the existing geological and geophysical exploration results, and density data;

[0139] A first correction module 620, configured to perform forward and inverse modeling of the residual gravity anomaly profile on the initial model to obtain a first corrected model;

[0140] A second correction module 630, configured to perform forward and inverse modeling of the horizontal gravity gradient anomaly profile on the first corrected model to obtain a second corrected model;

[0141] A third correction module 640, configured to perform forward and inverse modeling of the first vertical derivative of gravity anomaly profile on the second corrected model to obtain a third corrected model;

[0142] The loop correction module 650 is configured to return one or more steps of forward and inverse modeling of the remaining gravity anomaly profile, forward and inverse modeling of the gravity horizontal gradient anomaly profile, and forward and inverse modeling of the gravity vertical first derivative anomaly profile for the third correction model loop until the results of the forward and inverse modeling of the remaining gravity anomaly profile, the forward and inverse modeling of the gravity horizontal gradient anomaly profile, and the forward and inverse modeling of the gravity vertical first derivative anomaly profile all meet the preset conditions, and a final model is obtained.

[0143] In the solution of the present invention, without adding new other geophysical exploration and geological data, compared with the existing gravity profile forward and inverse modeling methods, the obtained geological model has higher accuracy, has more refined and accurate structural and fracture characteristics, makes the gravity exploration method further towards refinement, and plays a greater role in gravity exploration.

[0144] The embodiment of the present invention may further include a corresponding computer device. The computer device includes a memory, at least one processor, and a computer program stored on the memory and executable on the processor. When the processor executes the program, it executes any of the above methods.

[0145] Among them, the memory, as a non-volatile computer-readable storage medium, can be used to store non-volatile software programs, non-volatile computer-executable programs, and modules, such as the program instructions / modules corresponding to the gravity profile forward and inverse modeling method in the embodiment of the present application. The processor executes various functional applications and data processing of the device by running the non-volatile software programs, instructions, and modules stored in the memory, that is, implements the gravity profile forward and inverse modeling method in the above method embodiment.

[0146] The memory may include a program storage area and a data storage area. Among them, the program storage area can store an operating system and application programs required for at least one function; the data storage area can store data created according to the use of the device. In addition, the memory may include a high-speed random access memory, and may also include a non-volatile memory, such as at least one magnetic disk storage device, a flash memory device, or other non-volatile solid-state storage devices. In some embodiments, the memory may optionally include a memory remotely provided relative to the processor, and these remote memories can be connected to the local module through a network. Examples of the above network include but are not limited to the Internet, an enterprise intranet, a local area network, a mobile communication network, and combinations thereof.

[0147] Finally, it should be noted that those of ordinary skill in the art can understand that all or part of the processes in the above-described method embodiments can be completed by instructing relevant hardware through a computer program. The program can be stored in a computer-readable storage medium. When the program is executed, it can include the processes of the above-described method embodiments. Among them, the storage medium of the program can be a magnetic disk, an optical disk, a read-only memory (ROM), or a random access memory (RAM), etc. The embodiments of the above computer program can achieve the same or similar effects as the corresponding foregoing method embodiments.

[0148] Those skilled in the art will also understand that the various exemplary logical blocks, modules, circuits, and algorithm steps described in connection with the disclosure herein can be implemented as electronic hardware, computer software, or a combination of both. To clearly illustrate this interchangeability of hardware and software, a general description of the functionality of various illustrative components, blocks, modules, circuits, and steps has been presented. Whether this functionality is implemented as software or hardware depends upon the particular application and the design constraints imposed on the overall system. The functionality that can be implemented in various ways for each particular application by those skilled in the art, but such implementation decisions should not be construed as causing a departure from the scope of the disclosure of the embodiments of the present invention.

[0149] The above are the exemplary embodiments disclosed by the present invention. However, it should be noted that various changes and modifications can be made without departing from the scope of the disclosure of the embodiments of the present invention as defined by the claims. The functions, steps, and / or actions of the method claims according to the disclosed embodiments herein need not be performed in any particular order. The above serial numbers of the disclosed embodiments of the present invention are only for description and do not represent the superiority or inferiority of the embodiments. In addition, although the elements disclosed in the embodiments of the present invention can be described or claimed in an individual form, they can also be understood as multiple unless clearly limited to the singular.

[0150] Those of ordinary skill in the art should understand that: The discussion of any of the above embodiments is only exemplary 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; Under the concept of the embodiments of the present invention, the technical features between the above embodiments or different embodiments can also be combined, and there are many other variations in different aspects of the above embodiments of the present invention, which are not provided in detail for the sake of brevity. Therefore, any omission, modification, equivalent replacement, improvement, etc. made within the spirit and principle of the embodiments of the present invention shall be included within the protection scope of the embodiments of the present invention.

Claims

1. A forward and inverse gravity profiling method, characterized in that, Including: Construct an initial model based on the gravity data of the study area, existing geological and geophysical exploration results, and density data; Perform forward and inverse modeling of the residual gravity anomaly profile for the initial model to obtain a first corrected model; Perform forward and inverse modeling of the gravity horizontal gradient anomaly profile for the first corrected model to obtain a second corrected model; Perform forward and inverse modeling of the gravity vertical first derivative anomaly profile for the second corrected model to obtain a third corrected model; Return to perform one or more of the steps of forward and inverse modeling of the residual gravity anomaly profile, forward and inverse modeling of the gravity horizontal gradient anomaly profile, and forward and inverse modeling of the gravity vertical first derivative anomaly profile on the third corrected model until the results of the forward and inverse modeling of the residual gravity anomaly profile, forward and inverse modeling of the gravity horizontal gradient anomaly profile, and forward and inverse modeling of the gravity vertical first derivative anomaly profile all meet the preset conditions to obtain a final model.

2. The method according to claim 1, wherein Constructing an initial model based on the gravity data of the study area, existing geological and geophysical exploration results, and density data includes: Obtain Bouguer gravity anomaly data based on the gravity data; Obtain the measured residual gravity anomaly based on the Bouguer gravity anomaly data and the topography of the study area; Construct an initial model based on the measured residual gravity anomaly, existing geological and geophysical exploration results, and density data.

3. The method according to claim 2, wherein Further including: Perform horizontal gradient modulus calculation and vertical first derivative calculation on the measured residual gravity anomaly respectively to obtain the measured gravity horizontal gradient anomaly and the measured gravity vertical first derivative anomaly.

4. The method according to claim 3, wherein Performing forward and inverse modeling of the residual gravity anomaly profile for the initial model to obtain a first corrected model includes: Perform forward gravity modeling on the initial model to obtain the gravity anomaly of the initial model; Perform fitting comparison between the gravity anomaly of the initial model and the measured residual gravity anomaly; Modify the initial model based on the fitting comparison between the gravity anomaly of the initial model and the measured residual gravity anomaly to obtain the first corrected model.

5. The method according to claim 4, wherein Modifying the initial model based on the fitting comparison between the gravity anomaly of the initial model and the measured residual gravity anomaly to obtain the first corrected model includes: Modify the initial model based on the fitting comparison between the gravity anomaly of the initial model and the measured residual gravity anomaly to obtain a first initial corrected model; Perform forward gravity modeling on the first initial corrected model to obtain the gravity anomaly of the first initial corrected model; Perform fitting comparison between the gravity anomaly of the first initial corrected model and the measured residual gravity anomaly; If the fitting comparison between the gravity anomaly of the first initial corrected model and the measured residual gravity anomaly does not meet the preset conditions, modify the first initial corrected model and return to the step of performing forward gravity modeling on the modified model until the fitting comparison between the gravity anomaly of the modified model and the measured residual gravity anomaly meets the preset conditions to obtain the final first corrected model.

6. The method according to claim 5, characterized in that, Further including: If the fitting comparison between the gravity anomaly of the first initial corrected model and the measured residual gravity anomaly meets the preset conditions, determine the first initial corrected model as the final first corrected model.

7. The method according to claim 4, characterized in that Performing forward and inverse modeling of the gravity horizontal gradient anomaly profile for the first corrected model to obtain a second corrected model includes: Perform forward calculation of the gravity horizontal gradient for the first correction model to obtain the gravity horizontal gradient anomaly of the first correction model; Perform fitting comparison between the gravity horizontal gradient anomaly of the first correction model and the measured gravity horizontal gradient anomaly; Modify the first correction model based on the fitting comparison between the gravity horizontal gradient anomaly of the first correction model and the measured gravity horizontal gradient anomaly to obtain the second correction model.

8. The method according to claim 7, characterized in that, Modifying the first correction model based on the fitting comparison between the gravity horizontal gradient anomaly of the first correction model and the measured gravity horizontal gradient anomaly to obtain the second correction model includes: Modify the first correction model based on the fitting comparison between the gravity horizontal gradient anomaly of the first correction model and the measured gravity horizontal gradient anomaly to obtain a second initial correction model; Perform forward calculation of the gravity horizontal gradient for the second initial correction model to obtain the gravity horizontal gradient anomaly of the second initial correction model; Perform fitting comparison between the gravity horizontal gradient anomaly of the second initial correction model and the measured gravity horizontal gradient anomaly; If the fitting comparison between the gravity horizontal gradient anomaly of the second initial correction model and the measured gravity horizontal gradient anomaly does not meet the preset conditions, modify the second initial correction model and return to the step of performing forward calculation of the gravity horizontal gradient for the modified model until the fitting comparison between the gravity horizontal gradient anomaly of the modified model and the measured gravity horizontal gradient anomaly meets the preset conditions to obtain the final second correction model.

9. The method according to claim 8, wherein Further includes: If the fitting comparison between the gravity horizontal gradient anomaly of the second initial correction model and the measured gravity horizontal gradient anomaly meets the preset conditions, determine the second initial correction model as the final second correction model.

10. The method according to claim 7, characterized in that Perform forward and inverse calculations of the gravity vertical first derivative anomaly profile for the second correction model to obtain a third correction model, including: Perform forward calculation of the gravity vertical first derivative for the second correction model to obtain the gravity vertical first derivative anomaly of the second correction model; Perform fitting comparison between the gravity vertical first derivative anomaly of the second correction model and the measured gravity vertical first derivative anomaly; Modify the second correction model based on the fitting comparison between the gravity vertical first derivative anomaly of the second correction model and the measured gravity vertical first derivative anomaly to obtain the third correction model.

11. The method according to claim 10, characterized in that, Modifying the second correction model based on the fitting comparison between the gravity vertical first derivative anomaly of the second correction model and the measured gravity vertical first derivative anomaly to obtain the third correction model includes: Modify the second correction model based on the fitting comparison between the gravity vertical first derivative anomaly of the second correction model and the measured gravity vertical first derivative anomaly to obtain a third initial correction model; Perform forward calculation of the gravity vertical first derivative for the third initial correction model to obtain the gravity vertical first derivative anomaly of the third initial correction model; Perform fitting comparison between the gravity vertical first derivative anomaly of the third initial correction model and the measured gravity vertical first derivative anomaly; If the fitting comparison between the vertical first derivative anomaly of gravity of the third initial correction model and the measured vertical first derivative anomaly of gravity does not meet the preset conditions, modify the third initial correction model and return to the step of performing forward calculation of the vertical first derivative of gravity on the modified model until the fitting comparison between the vertical first derivative anomaly of gravity of the modified model and the measured vertical first derivative anomaly of gravity meets the preset conditions, and obtain the final third correction model.

12. The method according to claim 11, wherein Further comprising: If the fitting comparison between the vertical first derivative anomaly of gravity of the third initial correction model and the measured vertical first derivative anomaly of gravity meets the preset conditions, determine the third initial correction model as the final third correction model.

13. A gravity profile forward and inverse inversion device, characterized in that, Comprising: A construction module configured to construct an initial model based on the gravity data of the study area, the existing geological and geophysical exploration results, and density data; A first correction module configured to perform forward and inverse calculations of the residual gravity anomaly profile on the initial model to obtain a first correction model; A second correction module configured to perform forward and inverse calculations of the gravity horizontal gradient anomaly profile on the first correction model to obtain a second correction model; A third correction module configured to perform forward and inverse calculations of the vertical first derivative anomaly profile of gravity on the second correction model to obtain a third correction model; A cyclic correction module configured to return to perform one or more of the steps of forward and inverse calculations of the residual gravity anomaly profile, forward and inverse calculations of the gravity horizontal gradient anomaly profile, and forward and inverse calculations of the vertical first derivative anomaly profile of gravity on the third correction model until the results of the forward and inverse calculations of the residual gravity anomaly profile, forward and inverse calculations of the gravity horizontal gradient anomaly profile, and forward and inverse calculations of the vertical first derivative anomaly profile of gravity all meet the preset conditions, and obtain the final model.

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