Method and system for evaluating fault sealing property of sandstone reservoir based on three-dimensional geological modeling

Abstract

The application relates to a sandstone reservoir fault sealing evaluation method and system based on three-dimensional geological modeling, which comprises the following steps: calculating a normal pressure of a fault surface, and calculating a conversion depth according to the normal pressure of the fault surface; calculating a displacement pressure of an arbitrary point on the fault surface according to the conversion depth; obtaining a displacement pressure curve according to a three porosity logging curve, and obtaining a three-dimensional geological model through three-dimensional geological modeling according to the displacement pressure curves of various drillings; reading the displacement pressure in a neighboring model grid of the fault according to the three-dimensional geological model, comparing the displacement pressure in the neighboring model grid with the displacement pressure of the arbitrary point, judging the fault sealing, comparing the displacement pressure on the entire fault surface and the displacement pressure of the neighboring simulation grid in sequence, and obtaining the three-dimensional space fault surface sealing distribution characteristics. The relationship between the permeability and the displacement pressure established by the application can not only evaluate the sealing of the fault in the pure sandstone reservoir, but also evaluate the sealing of the fault in the sandstone and mudstone reservoir, and the application range is wider.

Description

Technical Field

[0001] This invention relates to a method, system, and readable medium for evaluating the fault sealing of sandstone reservoirs based on three-dimensional geological modeling, belonging to the field of sandstone reservoir fault evaluation technology. Background Technology

[0002] Normal faults in sandstone reservoirs, where sandstone meets sandstone, are generally considered to have very poor sealing properties, serving almost no sealing function. Most domestic and international research on fault sealing is qualitative, with limited quantitative studies. Quantitative research on fault sealing primarily falls into two categories: one based on geological studies, including methods such as the fault mudstone ratio (SGR), Knipe diagrams, physical simulations, core analysis, seismic and well logging interpretation; the other based on mathematical methods, such as sealing coefficients, tightness indexes, nonlinear mapping, grey relational analysis, logical information methods, and fuzzy comprehensive evaluation. Among these geological methods, calculating mud content and evaluating mudstone smearing seem indispensable, while the essential factor for fault sealing is differential displacement pressure. In recent years, some scholars have also used the displacement pressure difference between faults and reservoirs to quantitatively evaluate fault sealing. However, existing technologies also require the analysis of mudstone content and its displacement pressure when calculating displacement pressure. For reservoirs with very low mudstone content, the existing methods pose a challenge to evaluating fault sealing in sandstone reservoirs.

[0003] Since the study of fault sealing, the argillaceous content of fault rocks has been a perennial topic in the quantitative analysis of fault sealing. Methods such as the SGR method and the Knipe diagram method are mainly based on the analysis of argillaceous content in fault rocks. The fundamental reason is that the fine mudstone particles, existing between other clastic particles, reduce porosity and permeability, thereby increasing displacement pressure. However, discussing the impact of argillaceous content on fault sealing in sandstone reservoirs with extremely low argillaceous content is futile. For study areas lacking data on mudstone displacement pressure and coring data at fault points, core analysis data and well logging data must be fully utilized. Methods related to argillaceous content calculation are no longer applicable in pure sandstone reservoirs.

[0004] Geomechanical methods can be used to evaluate the sealing performance of faults in sandstone reservoirs. When the reservoir displacement pressure is greater than the fault displacement pressure, the fault does not play a sealing role; when the reservoir displacement pressure is less than the fault displacement pressure, the fault seals the reservoir. The quantitative evaluation method for fault sealing proposed by predecessors provides a framework for the detailed evaluation of fault sealing performance, but there are two problems: (1) The calculation of the fault plane normal pressure does not take into account the horizontal stress, which directly leads to the underestimation of the fault plane normal pressure depth and the underestimation of the displacement pressure; (2) The establishment of the depth and displacement pressure chart requires at least knowing the displacement pressure values ​​of pure mudstone and pure sandstone core samples. However, most core analysis in oilfields is conducted in the reservoir section, and physical property analysis of mudstone is rarely performed. Therefore, this method is not applicable to sandstone reservoirs. Summary of the Invention

[0005] To address the aforementioned problems, the present invention aims to provide a method, system, and readable medium for evaluating the sealing performance of sandstone reservoir faults based on three-dimensional geological modeling. This method overcomes the limitations of calculating clay content and can reflect the displacement pressure of mudstone using permeability, eliminating the need to consider the relationship between clay content and displacement pressure. Furthermore, the established relationship between permeability and displacement pressure can evaluate not only the sealing performance of faults in pure sandstone reservoirs but also that in sandstone-mudstone reservoirs, thus broadening its application scope.

[0006] To achieve the above objectives, the present invention proposes the following technical solution: a method for evaluating the fault sealing of sandstone reservoirs based on three-dimensional geological modeling, comprising the following steps: calculating the normal pressure of the fault plane and calculating the equivalent depth based on the normal pressure of the fault plane; calculating the displacement pressure at any point on the fault plane based on the equivalent depth; obtaining the displacement pressure curve based on the three-porosity logging curve; obtaining a three-dimensional geological model through three-dimensional geological modeling based on the displacement pressure curve of each well; reading the displacement pressure in the adjacent model grid of the fault based on the three-dimensional geological model; comparing the displacement pressure in the adjacent model grid with the displacement pressure at any point to determine the fault sealing; and sequentially comparing the displacement pressure on the entire fault plane and the displacement pressure of its adjacent simulated grids to obtain the three-dimensional spatial distribution characteristics of the fault plane sealing.

[0007] Furthermore, the formula for calculating the normal pressure at the fault plane is as follows:

[0008] in, It is the normal pressure at the fault surface. It is the maximum horizontal vertical principal stress. It is the minimum horizontal vertical principal stress. It is the vertical principal stress. It is the acute angle between the maximum vertical principal stresses. It is the dip angle of the fault plane. The normal pressure of the fault plane is taken as the vertical principal stress of the fault plane, and the equivalent depth of the fault plane is calculated by the formula of vertical principal stress.

[0009] Furthermore, the maximum horizontal vertical principal stress:

[0010] Minimum horizontal vertical principal stress:

[0011] Vertical principal stress:

[0012] Formation pressure:

[0013] in Poisson's ratio, denoted as the average density of the overlying rocks, h as the burial depth of the strata, H as the reservoir elevation depth, and g as the gravity constant.

[0014] Furthermore, the method for calculating the displacement pressure at any point on the fault plane based on the reduced depth is as follows: calculate the reduced porosity at any point on the fault plane; calculate the reduced permeability at any point on the fault plane based on the reduced porosity; and calculate the displacement pressure at any point on the fault plane based on the reduced permeability.

[0015] Furthermore, the relationship between the displacement pressure at any point and the calculated depth is fitted. If the correlation coefficient of the relationship is greater than a threshold, the calculated depth is directly input into the relationship to obtain the displacement pressure at any point on the fault plane when calculating the displacement pressure. If the correlation coefficient of the relationship is less than or equal to the threshold, the displacement pressure at any point on the fault plane is recalculated.

[0016] Furthermore, the method for calculating the reduced porosity at any point on the fault plane is as follows: based on the reduced depth, calculate the reduced acoustic transit time at any point on the fault plane; based on the reduced acoustic transit time, calculate the reduced density at any point on the fault plane; based on the reduced density, calculate the reduced porosity at any point on the fault plane using the fitting formula between rock density and porosity.

[0017] Furthermore, the relationship between porosity and equivalent depth at any point is fitted. If the correlation coefficient of the relationship is greater than a threshold, the equivalent depth is directly input into the relationship to obtain the porosity at any point on the fault plane when calculating the porosity. If the correlation coefficient of the relationship is less than or equal to the threshold, the porosity at any point on the fault plane is recalculated.

[0018] Furthermore, the method for obtaining the displacement pressure curve based on the three-porosity logging curve is as follows: using the three-porosity logging curve and the corresponding porosity calculation formula, calculate the porosity of each well to obtain the logging interpretation porosity curve; based on the logging interpretation porosity curve, calculate the permeability of each well to obtain the logging interpretation permeability curve; based on the logging interpretation permeability curve, calculate the displacement pressure of each well to obtain the displacement pressure curve.

[0019] This invention also discloses a sandstone reservoir fault sealing evaluation system based on three-dimensional geological modeling, comprising: a conversion depth calculation module for calculating the fault plane normal pressure and calculating the conversion depth based on the fault plane normal pressure; a fault plane displacement pressure calculation module for calculating the displacement pressure at any point on the fault plane based on the conversion depth; a three-dimensional geological model establishment module for obtaining the displacement pressure curve based on the three-porosity logging curve, and obtaining a three-dimensional geological model through three-dimensional geological modeling based on the displacement pressure curve of each well; and a sealing distribution feature acquisition module for reading the displacement pressure in the adjacent model grid of the fault based on the three-dimensional geological model, comparing the displacement pressure in the adjacent model grid with the displacement pressure at any point to determine the fault sealing, and sequentially comparing the displacement pressure on the entire fault plane and the displacement pressure of its adjacent simulated grids to obtain the three-dimensional spatial fault plane sealing distribution features.

[0020] The present invention also discloses a computer-readable storage medium storing a computer program, which is executed by a processor to implement the method for fault sealing of sandstone reservoirs based on three-dimensional geological modeling as described in any of the preceding claims.

[0021] The present invention has the following advantages due to the adoption of the above technical solutions: 1. This invention establishes the correlation between cross-sectional normal pressure, burial depth, sonic transit time, rock porosity, rock permeability and displacement pressure, and can calculate fault displacement pressure even in areas where fault clay content parameters are lacking.

[0022] 2. This invention establishes the correlation between the three-porosity curve and porosity, permeability, and displacement pressure in drilling, and the displacement pressure curve can be obtained on the drilling site.

[0023] 3. Based on three-dimensional geological modeling, this invention can obtain the phase-controlled permeability model of the study area, and use relevant formulas to calculate the displacement pressure model of the entire reservoir in the study area, and calculate the three-dimensional distribution of the displacement pressure of the entire fault.

[0024] 4. This invention can compare the displacement pressure of each part of the fault plane with the displacement pressure of the nearby reservoir to determine the sealing of each part of the fault.

[0025] 5. The three-dimensional geological model of displacement pressure established in this invention can effectively evaluate the displacement pressure in different parts of the reservoir, which is of great significance for oil and gas field reserve calculation, sandstone reservoir conductivity assessment and well location deployment.

[0026] In summary, this invention can be widely applied to methods and systems for evaluating the fault sealing properties of sandstone reservoirs. Attached Figure Description

[0027] Figure 1 This is a flowchart of a method for evaluating the fault sealing of sandstone reservoirs using three-dimensional geological modeling, according to an embodiment of the present invention. Figure 2 This is a schematic diagram of the linear relationship between acoustic time difference and burial depth in one embodiment of the present invention; Figure 3 This is a schematic diagram of the linear relationship between rock density and acoustic transit time in one embodiment of the present invention; Figure 4 This is a schematic diagram of the linear relationship between rock density and porosity in one embodiment of the present invention; Figure 5 This is a schematic diagram illustrating the fitting index relationship between permeability and porosity in one embodiment of the present invention; Figure 6 This is a schematic diagram illustrating the logarithmic relationship between displacement pressure and permeability in one embodiment of the present invention; Figure 7 This is a schematic diagram comparing the displacement pressure values ​​in the fault zone and the adjacent reservoir grid in one embodiment of the present invention; Figure 8 This is a schematic diagram illustrating the determination of the closure of any part on the cross-section in one embodiment of the present invention. Detailed Implementation

[0028] To enable those skilled in the art to better understand the technical solutions of the present invention, the present invention is described in detail through specific embodiments. However, it should be understood that the specific embodiments are provided only for a better understanding of the present invention and should not be construed as limiting the present invention. In the description of the present invention, it should be understood that the terminology used is for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0029] To address the limitations of existing technologies in evaluating fault sealing, such as reliance on formation clay content and inconsistent sealing across different depths and segments of the same fault, this invention proposes a method, system, and readable medium for evaluating the sealing of sandstone reservoir faults based on three-dimensional geological modeling. The method includes the following steps: calculating the normal pressure of the fault plane and calculating the equivalent depth based on the normal pressure; calculating the displacement pressure at any point on the fault plane based on the equivalent depth; obtaining the displacement pressure curve based on the three-porosity logging curves; obtaining a three-dimensional geological model based on the displacement pressure curves of each well through three-dimensional geological modeling; reading the displacement pressure in adjacent model grids of the fault based on the three-dimensional geological model; comparing the displacement pressure in adjacent model grids with the displacement pressure at any point to determine the fault sealing; and sequentially comparing the displacement pressure across the entire fault plane with the displacement pressure in adjacent simulated grids to obtain the three-dimensional spatial distribution characteristics of the fault plane sealing.

[0030] This invention first breaks through the limitations of calculating clay content, allowing the displacement pressure of mudstone to be reflected by permeability, eliminating the need to consider the relationship between clay content and displacement pressure. The established permeability-displacement pressure relationship can evaluate not only the sealing performance of faults in pure sandstone reservoirs but also that in sandstone-mudstone reservoirs, broadening its application scope. Secondly, this invention enables the evaluation of sealing performance at different locations within faults, providing more refined results and offering significant guidance for assessing the sand body and fault connectivity of sandstone reservoirs. It avoids dependence on clay content, and the established permeability-displacement pressure relationship can evaluate not only the sealing performance of faults in pure sandstone reservoirs but also that in sandstone-mudstone reservoirs, broadening its application scope and achieving the goal of quantitatively determining the sealing performance at any location on the fault plane. It provides a valid basis for evaluating the sand body and fault connectivity of sandstone reservoirs. The following detailed description of the invention, in conjunction with the accompanying drawings, through embodiments, further illustrates the invention.

[0031] Example 1 This embodiment uses the Qigu Formation sandstone and conglomerate reservoir in the Che 60 well area of ​​the Junggar Basin, China, as an example to illustrate in detail the fault sealing evaluation method for sandstone reservoirs based on three-dimensional geological modeling of the present invention. Figure 1 As shown, it includes the following steps: S1 calculates the normal pressure at the fault plane and calculates the equivalent depth based on the normal pressure at the fault plane; The normal force at the fault plane is obtained based on the principle of force decomposition and composition. In this embodiment, taking the F3 fault as an example, the cross-sectional normal pressure of fault F3 was calculated. The calculation formula is:

[0032] in, It is the normal pressure at the fault surface. It is the maximum horizontal vertical principal stress. It is the minimum horizontal vertical principal stress. It is the vertical principal stress. It is the acute angle between the maximum vertical principal stresses. It is the dip angle of the fault plane.

[0033] Maximum horizontal vertical principal stress:

[0034] Minimum horizontal vertical principal stress:

[0035] Vertical principal stress:

[0036] Formation pressure:

[0037] in Poisson's ratio, Let be the average density of the overlying rock, h be the burial depth of the strata, H be the reservoir elevation depth, and g be the gravity constant. Fault F1 strikes at 275°, forming an acute angle with the maximum vertical principal stress. The angle is 68°. The strike of fault F2 is 287°, which is the acute angle with the maximum vertical principal stress. The angle is 56°; the strike of fault F3 is 296°, which is the acute angle with the maximum vertical principal stress. The dip angle of the fault plane is 58.3°. It is 85°.

[0038] normal pressure at the fault plane Vertical principal stress at the fault plane The equivalent depth h of the fault plane was calculated using the vertical principal stress formula. f Taking fault F3 as an example, the calculation results are shown in Table 1.

[0039] S2 calculates the displacement pressure at any point on the fault plane based on the reduced depth.

[0040] The method for calculating the displacement pressure at any point on the fault plane based on the reduced depth is as follows: S2.1 Calculate the reduced porosity at any point on the fault plane; The method for calculating the reduced porosity at any point on the fault plane is as follows: S2.1.1 Based on the calculated depth h f The reduced acoustic transit time AC at any point on the fault plane is calculated by fitting a linear relationship between burial depth and acoustic transit time. f The linear relationship between burial depth and acoustic transit time is shown in the figure below. Figure 2 As shown, the obtained linear relationship between burial depth and acoustic transit time is:

[0041] Where h is the burial depth of the strata, and the correlation is... .

[0042] S2.1.2 Based on the calculated acoustic time difference AC f The reduced density (DEN) at any point on the fault plane was calculated by fitting a linear relationship between acoustic transit time and rock density. f The linear relationship between acoustic transit time and rock density is as follows: Figure 3 As shown, the obtained linear relationship between acoustic transit time and rock density is:

[0043] Its correlation .

[0044] S2.1.3 Based on the converted density DEN f The reduced porosity (POR) at any point on the fault plane is calculated by fitting a linear relationship between rock density and porosity. f The linear relationship between rock density and porosity is shown in the figure. Figure 4 As shown, the obtained linear relationship between rock density and porosity is:

[0045] Its correlation .

[0046] Porosity POR at any point f With the conversion depth h f The relationship is fitted, and if the correlation coefficient of the relationship is greater than the threshold, then when calculating porosity, the converted depth h is directly used. f Input the formula to obtain the porosity POR at any point on the fault plane. f If the correlation coefficient of the relationship is less than or equal to the threshold, then the porosity POR at any point on the fault plane is recalculated. f In this embodiment, the threshold value is preferably 0.6, but this value is only illustrative and not intended to be limiting.

[0047] S2.2 Based on the calculated porosity POR f The reduced permeability PERM at any point on the fault plane is calculated by fitting a linear relationship between porosity and permeability. f The linear relationship between porosity and permeability is as follows: Figure 5 As shown, the obtained linear relationship between porosity and permeability is:

[0048] Its correlation .

[0049] S2.3 Based on PERM (Permeability Calculation) f The displacement pressure P at any point on the fault plane is calculated by fitting a logarithmic relationship between permeability and displacement pressure. rf The logarithmic relationship between permeability and displacement pressure is as follows: Figure 6 As shown, the obtained logarithmic relationship between permeability and displacement pressure is:

[0050] Its correlation .

[0051] Displacement pressure P at any point rf With the conversion depth h f The relationship is fitted, and if the correlation coefficient of the relationship is greater than the threshold, then when calculating the displacement pressure, the conversion depth h is directly used. f Input the relational expression to obtain the displacement pressure P at any point on the fault plane. rf If the correlation coefficient of the relationship is less than or equal to the threshold, then the displacement pressure P at any point on the fault plane is recalculated. rf In this embodiment, the threshold value is preferably 0.6, but this value is only illustrative and not intended to be limiting.

[0052] S3 obtains the displacement pressure curve P based on the three-porosity logging curve. r Based on the displacement pressure curve P of each well r A three-dimensional geological model M is obtained through three-dimensional geological modeling.

[0053] The method for obtaining the displacement pressure curve based on the three-porosity logging curve is as follows: S3.1 The porosity of each well is calculated using the three-porosity logging curves and the corresponding porosity calculation formula. The calculation formula for the logging interpretation porosity curve can be obtained by linearly fitting the porosity from core testing with the logging curve value. The logging interpretation porosity curve (POR) is obtained based on the calculation formula for the interpretation porosity curve. In this embodiment, through... Calculate the porosity for drilling.

[0054] S3.2 Based on the porosity curve (POR) interpreted from the well logging, the permeability of each well is calculated using the fitting exponential relationship between porosity and permeability. In this embodiment, the formula is used. The permeability of each well was calculated, and the well logging interpretation permeability curve PERM was obtained.

[0055] S3.3 Based on the PERM permeability curve interpreted from well logging, the logarithmic relationship between permeability and displacement pressure is fitted using the formula in this embodiment. Calculate the displacement pressure for each well to obtain the displacement pressure curve P. r .

[0056] Based on the displacement pressure curves P of each well r A three-dimensional geological model M of displacement pressure in the study area was obtained using the Petrel software reservoir three-dimensional geological modeling method.

[0057] S4 reads the displacement pressure P in the adjacent model grid of the fault based on the three-dimensional geological model M. rm The displacement pressure P in the adjacent model mesh rm Displacement pressure P at any point rf Compare and determine the fault sealing, such as Figure 7 As shown, the displacement pressure on the entire fault plane and the displacement pressure of its adjacent simulated grids are compared sequentially to obtain the three-dimensional spatial fault plane closure distribution characteristics. In this embodiment, the closure of any part of the fault plane of faults F1, F2, and F3 is determined, such as... Figure 8 As shown.

[0058] According to this embodiment, the fault sealing of the Qigu Formation sandstone and conglomerate reservoir in the Che60 well area of ​​the Junggar Basin can be more quantitatively determined, thereby guiding the calculation of Qigu Formation reserves and the adjustment of injection-production well network.

[0059] Example 2 Based on the same inventive concept, this embodiment discloses a sandstone reservoir fault sealing evaluation system based on three-dimensional geological modeling, including: The conversion depth calculation module is used to calculate the normal pressure at the fault plane and calculate the conversion depth based on the normal pressure at the fault plane. The fault plane displacement pressure calculation module is used to calculate the displacement pressure at any point on the fault plane based on the conversion depth. The 3D geological model building module is used to obtain the displacement pressure curve based on the three-porosity logging curve, and to obtain the 3D geological model through 3D geological modeling based on the displacement pressure curve of each well. The module for obtaining the closed distribution characteristics is used to read the displacement pressure in the adjacent model grids of the fault based on the three-dimensional geological model, compare the displacement pressure in the adjacent model grids with the displacement pressure at any point to determine the fault closedness, and then compare the displacement pressure on the entire fault plane with the displacement pressure of its adjacent simulated grids to obtain the three-dimensional spatial fault plane closedness distribution characteristics.

[0060] Example 2 Based on the same inventive concept, this embodiment discloses a computer-readable storage medium storing a computer program, which is executed by a processor to implement any of the above-mentioned methods for fault sealing of sandstone reservoirs based on three-dimensional geological modeling.

[0061] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0062] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0063] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0064] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0065] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific embodiments of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the protection scope of the claims of the present invention. The above content is only a specific embodiment of this application, but the protection scope of this application is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be covered within the protection scope of this application. Therefore, the protection scope of this application should be determined by the protection scope of the claims.

Claims

1. A method for evaluating the fault sealing performance of sandstone reservoirs based on three-dimensional geological modeling, characterized in that, Includes the following steps: Calculate the normal pressure at the fault plane, and calculate the equivalent depth based on the normal pressure at the fault plane; The displacement pressure at any point on the fault plane can be calculated based on the calculated depth, and the displacement pressure can also be calculated in areas where fault clay content parameters are lacking. Displacement pressure curves are obtained based on the three-porosity logging curves. Based on the displacement pressure curves of each well, a three-dimensional geological model is obtained through three-dimensional geological modeling. The displacement pressure in the adjacent model grid of the fault is read from the three-dimensional geological model. The displacement pressure in the adjacent model grid is compared with the displacement pressure at any point to determine the fault closure. The displacement pressure on the entire fault plane and the displacement pressure of its adjacent simulated grid are compared in turn to obtain the three-dimensional spatial fault plane closure distribution characteristics. The method for calculating the displacement pressure at any point on the fault plane based on the aforementioned reduced depth is as follows: Calculate the reduced porosity at any point on the fault plane; Calculate the reduced permeability at any point on the cross-section based on the reduced porosity; Based on the calculated permeability, the displacement pressure at any point on the fault plane is calculated.

2. The method for evaluating the fault sealing performance of sandstone reservoirs based on three-dimensional geological modeling as described in claim 1, characterized in that, The formula for calculating the normal pressure at the fault plane is: in, It is the normal pressure at the fault surface. It is the maximum horizontal vertical principal stress. It is the minimum horizontal vertical principal stress. It is the vertical principal stress. It is the acute angle between the maximum vertical principal stresses. It is the dip angle of the fault plane. The normal pressure of the fault plane is taken as the vertical principal stress of the fault plane, and the equivalent depth of the fault plane is calculated by the formula of vertical principal stress.

3. The method for evaluating the fault sealing performance of sandstone reservoirs based on three-dimensional geological modeling as described in claim 2, characterized in that, Maximum horizontal vertical principal stress: Minimum horizontal vertical principal stress: Vertical principal stress: Formation pressure: in Poisson's ratio, denoted as the average density of the overlying rocks, h as the burial depth of the strata, H as the reservoir elevation depth, and g as the gravity constant.

4. The method for evaluating the fault sealing performance of sandstone reservoirs based on three-dimensional geological modeling as described in claim 1, characterized in that, The relationship between the displacement pressure at any point and the calculated depth is fitted. If the correlation coefficient of the relationship is greater than a threshold, the calculated depth is directly input into the relationship to obtain the displacement pressure at any point on the fault plane when calculating the displacement pressure. If the correlation coefficient of the relationship is less than or equal to the threshold, the displacement pressure at any point on the fault plane is recalculated.

5. The method for evaluating the fault sealing performance of sandstone reservoirs based on three-dimensional geological modeling as described in claim 1, characterized in that, The method for calculating the reduced porosity at any point on the fault plane is as follows: Based on the calculated depth, calculate the calculated acoustic time difference at any point on the fault plane; Based on the reduced acoustic transit time, calculate the reduced density at any point on the fault plane; Based on the reduced density, the reduced porosity at any point on the fault plane is calculated using the fitting formula between rock density and porosity.

6. The method for evaluating the fault sealing performance of sandstone reservoirs based on three-dimensional geological modeling as described in claim 5, characterized in that, The relationship between porosity and equivalent depth at any point is fitted. If the correlation coefficient of the relationship is greater than a threshold, the equivalent depth is directly input into the relationship to obtain the porosity at any point on the fault plane when calculating the porosity. If the correlation coefficient of the relationship is less than or equal to the threshold, the porosity at any point on the fault plane is recalculated.

7. The method for evaluating the fault sealing performance of sandstone reservoirs based on three-dimensional geological modeling as described in claim 1, characterized in that, The method for obtaining the displacement pressure curve based on the three-porosity logging curve is as follows: The porosity of each well is calculated using the three-porosity logging curves and the corresponding porosity calculation formulas, resulting in the logging interpretation porosity curves. Based on the well logging interpretation porosity curves, the permeability of each well is calculated to obtain the well logging interpretation permeability curves; Based on the well logging interpretation permeability curves, the displacement pressure of each well is calculated to obtain the displacement pressure curve.

8. A sandstone reservoir fault sealing evaluation system based on three-dimensional geological modeling, characterized in that, include: The conversion depth calculation module is used to calculate the normal pressure of the fault plane and calculate the conversion depth based on the normal pressure of the fault plane. The fault displacement pressure calculation module is used to calculate the displacement pressure at any point on the fault plane based on the calculated depth. It can also calculate the fault displacement pressure in areas where fault clay content parameters are lacking. The 3D geological model building module is used to obtain the displacement pressure curve based on the three-porosity logging curve, and to obtain the 3D geological model through 3D geological modeling based on the displacement pressure curve of each well. The closure distribution feature acquisition module is used to read the displacement pressure in the adjacent model grid of the fault according to the three-dimensional geological model, compare the displacement pressure in the adjacent model grid with the displacement pressure at any point, determine the fault closure, and sequentially compare the displacement pressure on the entire fault plane and the displacement pressure of its adjacent simulated grids to obtain the three-dimensional spatial fault plane closure distribution features. The method for calculating the displacement pressure at any point on the fault plane based on the aforementioned reduced depth is as follows: Calculate the reduced porosity at any point on the fault plane; Calculate the reduced permeability at any point on the cross-section based on the reduced porosity; Based on the calculated permeability, the displacement pressure at any point on the fault plane is calculated.

9. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program that is executed by a processor to implement the sandstone reservoir fault sealing method based on three-dimensional geological modeling as described in any one of claims 1-7.

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