Optimal network size selection method and system for geologic modeling of small-scale geologic body
By comparing the planar distribution of geological bodies and the interpretation results of well point reservoirs, a grid size optimization curve was plotted. By selecting a combination of grid sizes with an error less than the threshold, the problem of grid size dependence on experience in small-scale geological modeling was solved, and an optimal balance between accuracy and resources was achieved.
Patent Information
- Application Number
- CN202511075528.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-08-01
- Publication Date
- 2025-11-21
AI Technical Summary
In existing technologies, the grid size in geological modeling of small-scale geological bodies is usually set based on experience, lacking quantitative scientific basis, which leads to increased computational resource requirements and insufficient model accuracy.
By comparing the planar distribution of geological bodies with the planar gridding results, a planar grid size optimization curve is plotted. By comparing the well point reservoir interpretation conclusions with the vertical gridding results, a vertical grid size optimization curve is plotted. Combinations of grid sizes with errors less than a threshold are selected to generate a candidate set. Finally, the combination with the fewest total grids is selected as the optimal grid size.
It provides a quantitative basis for selecting grid size in geological modeling, realizes an optimal trade-off between characterization accuracy and grid number, and reduces the demand for computing resources.
Smart Images
Figure CN120997423A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a method and system for selecting the optimal network size in geological modeling of small-scale geological bodies, belonging to the field of petroleum geological modeling technology. Background Technology
[0002] The basic idea of geological modeling is to discretize strata into grid cells in both the planar and vertical directions, and then assign values to each cell to characterize different geological bodies and their internal properties (such as reservoir physical parameters). In this process, the selection of the grid size (planar and vertical) is crucial to the model quality. Theoretically, a smaller grid size can more accurately characterize the morphology of geological bodies and describe their internal property variations in more detail. Especially for small-scale geological bodies, a sufficiently fine grid is a necessary condition to ensure model accuracy to meet the requirements of subsequent work. However, an excessively small grid size will significantly increase computational resource requirements, posing a challenge to computer performance. Therefore, an optimal trade-off needs to be struck between representational accuracy and grid size (i.e., the total number of grid cells).
[0003] In current geological modeling practices, grid size is usually set directly to fixed values such as 25m or 50m based on experience. In fact, there is a lack of systematic optimization process for grid size and a lack of quantitative scientific basis. Summary of the Invention
[0004] To address the aforementioned problems, the purpose of this invention is to provide a method and system for selecting the optimal network size in geological modeling of small-scale geological bodies. This method solves the problem that the current geological modeling process relies on experience to determine the mesh size, which lacks quantitative basis.
[0005] To achieve the above objectives, the present invention proposes the following technical solution: a method for selecting the optimal network size for geological modeling of small-scale geological bodies, comprising the following steps: comparing the planar distribution of the geological body with the planar gridding results, and drawing a planar grid size optimization curve based on the comparison results; comparing the reservoir interpretation conclusions of all well points within the geological body with the vertical gridding results, and drawing a vertical grid size optimization curve based on the comparison results; selecting planar grid sizes with errors less than a threshold from the planar grid size optimization curves, selecting vertical grid sizes with errors less than a threshold from the vertical grid size optimization curves, adding the errors of the planar grid sizes and the vertical grid sizes to obtain the total error; selecting combinations whose total errors are still less than a threshold to generate a candidate grid size set; and selecting the grid size combination with the fewest total grids from the candidate grid size set as the optimal grid size combination.
[0006] Furthermore, the method for drawing the optimal curve for the planar grid size is as follows: draw a planar distribution map of the geological body based on its seismic attributes; sample the planar distribution map of the geological body using different planar grid sizes, and count the number of planar grids sampled from the geological body; calculate the planar area of the geological body based on the number of planar grids; calculate the error between the actual planar area of the geological body and the calculated planar area; draw a curve showing the change of the error of the planar area of the geological body with the planar grid size, and use this curve as the optimal curve for the planar grid size.
[0007] Furthermore, the formula for calculating the planar area of the geological body is as follows:
[0008] A2 = N A ×d 2
[0009] Where A2 is the calculated planar area of the geological body; N A d is the number of planar grids of the geological body; d is the side length of a single planar grid.
[0010] Furthermore, the formula for calculating the error in the planar area of the geological body is as follows:
[0011]
[0012] Where A1 is the actual planar area of the geological body; ε A It is an error in the planar area of the geological body.
[0013] Furthermore, the method for plotting the optimal vertical grid size curve is as follows: based on the reservoir interpretation conclusions of all well points within the geological body, calculate the true average reservoir thickness; sample the reservoir and non-reservoir interpretation conclusions at each well point using different vertical grid sizes, and count the average vertical grid number of the sampled geological body; calculate the average reservoir thickness obtained from the sampling based on the average vertical grid number; calculate the error between the true average reservoir thickness and the calculated average reservoir thickness, plot the curve of the error of the average reservoir thickness as a function of the vertical grid size, and use it as the optimal vertical grid size curve.
[0014] Furthermore, the formula for calculating the true average thickness of the reservoir is as follows:
[0015]
[0016] The formula for calculating the average number of grid cells in the vertical direction is:
[0017]
[0018] Where, N i n is the number of vertical grid points for each well point; n is the total number of well points. It is the true average thickness of the reservoir; H iIt is the thickness of the reservoir encountered at each well point; N H It is the average number of grid cells in the vertical direction.
[0019] Furthermore, the formula for calculating the average reservoir thickness is as follows:
[0020]
[0021] in, is the calculated average reservoir thickness; h is the longitudinal dimension of a single grid.
[0022] Furthermore, the formula for calculating the error of the average reservoir thickness is as follows:
[0023]
[0024] Where, ε H It represents the error in the average thickness of the reservoir.
[0025] Furthermore, the combination of grid sizes is represented as follows:
[0026] N t =N A ×N H ×n
[0027] Where, N t It is a combination of grid sizes; N A N is the number of planar grids of a geological body. H is the average number of grid cells in the vertical direction; n is the total number of well points.
[0028] This invention also discloses an optimal network size selection system for geological modeling of small-scale geological bodies, comprising: a planar grid size optimization curve drawing module, used to compare the planar distribution of the geological body with the planar gridding results, and draw a planar grid size optimization curve based on the comparison results; a vertical grid size optimization curve drawing module, used to compare the reservoir interpretation conclusions of all well points within the geological body with the vertical gridding results, and draw a vertical grid size optimization curve based on the comparison results; a total error calculation module, used to select planar grid sizes with errors less than a threshold from the planar grid size optimization curves, select vertical grid sizes with errors less than a threshold from the vertical grid size optimization curves, and add the errors of the selected planar grid sizes to the errors of the selected vertical grid sizes to obtain the total error; a candidate set generation module, used to select combinations whose total errors are still less than a threshold to generate a candidate grid size set; and a grid size selection module, used to select the grid size combination with the fewest total grids from the candidate grid size set as the optimal grid size combination.
[0029] The technical solution of the present invention has at least the following technical effects or advantages:
[0030] This invention provides a quantitative basis for determining the grid size in the geological modeling process by calculating the relative sampling error and grid size combination under different grid sizes in the plane and vertical direction, and realizes the optimal grid size that takes into account both the characterization accuracy and the number of grids. Attached Figure Description
[0031] Figure 1 This is a diagram of the planar sampling process when the planar grid size is 30m in one embodiment of the present invention. (a) is a planar distribution diagram of the geological body before sampling, and (b) is a planar distribution diagram of the geological body after sampling.
[0032] Figure 2 This is a preferred curve diagram of the planar grid size in one embodiment of the present invention;
[0033] Figure 3 This is a diagram of the longitudinal sampling process in one embodiment of the present invention when the longitudinal grid is 0.6m. (a) is a longitudinal distribution diagram of the geological body before sampling, and (b) is a longitudinal distribution diagram of the geological body after sampling.
[0034] Figure 4 This is a preferred curve of the longitudinal grid size in one embodiment of the present invention. Detailed Implementation
[0035] 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.
[0036] To address the problems in existing technologies, such as the lack of systematic optimization processes and quantitative scientific basis for grid size selection (which is often based on experience), this invention discloses a method and system for selecting the optimal grid size in geological modeling of small-scale geological bodies. The method compares the planar distribution map of the geological body with the planar gridding results, and plots a planar grid size-error curve based on the comparison. It also compares the wellpoint reservoir interpretation conclusions with the vertical gridding results, plotting a vertical grid size-error curve based on the comparison. Planar and vertical dimensions with errors less than a threshold are selected, and the combined total error is calculated. Combinations with total errors still less than the threshold are retained to form a candidate set. The planar-vertical dimension combination with the fewest total grids is selected from the candidate set as the optimal grid size. This provides a quantitative basis for determining grid size in geological modeling, achieving optimal grid size selection that balances representational accuracy and grid number. The following detailed description of the invention, with reference to the accompanying drawings and embodiments, further illustrates the solution.
[0037] Example 1
[0038] This embodiment discloses a method for selecting the optimal network size in geological modeling of small-scale geological bodies, taking the fluvial reservoir of the Q oilfield in the eastern offshore region as an example. The method includes the following steps:
[0039] S1 compares the planar distribution of geological bodies with the planar gridding results, and plots the optimal planar grid size curve based on the comparison results.
[0040] The method for drawing the optimal curve for planar grid size is as follows:
[0041] S1.1 Draw a planar distribution map of the geological bodies based on their seismic properties or geological understanding.
[0042] S1.2 Sampling of the planar distribution map of geological bodies was performed using different planar grid sizes, and the number N of planar grids that sampled the geological bodies was counted. A ,like Figure 1 As shown.
[0043] S1.3 Calculate the planar area A2 of the geological body based on the number of planar grids of the geological body.
[0044] The formula for calculating the planar area of a geological body is:
[0045] A2 = N A ×d 2
[0046] Where A2 is the calculated planar area of the geological body; N A d is the number of planar grids of the geological body; d is the side length of a single planar grid.
[0047] S1.4 The error ε between the calculated actual planar area A1 and the calculated planar area A2 of the geological body. A .
[0048] Error ε of the planar area of a geological body A The calculation formula is:
[0049]
[0050] Where A1 is the actual planar area of the geological body; ε A It is an error in the planar area of the geological body.
[0051] S1.5 Error ε in plotting the planar area of a geological body A The curve that varies with the size of the planar grid is used as the preferred curve for the planar grid size.
[0052] In this embodiment, the actual planar area A1 of the geological body is 1.63 km². 2 For a geological body with a planar area A2, taking d = 30m as an example, the grid area d 2=900m 2 The number of effective grids in the plane, N A =181, the planar sampling area A2 is 1.51km 2 Sampling area A2 and relative error ε corresponding to different planar grid sizes A As shown in Table 1, the preferred curves for the obtained planar mesh dimensions are as follows. Figure 2 As shown.
[0053] S2 compares the reservoir interpretation conclusions of all well points within the geological body with the vertical gridding results, and plots the optimal vertical grid size curve based on the comparison results.
[0054] The method for plotting the optimal curve for vertical grid size is as follows:
[0055] S2.1 Based on the reservoir interpretation conclusions of all well points within the geological body, calculate the true average thickness of the reservoir.
[0056] The formula for calculating the true average thickness of the reservoir is:
[0057]
[0058] Where n is the total number of well points; It is the true average thickness of the reservoir; H i This refers to the thickness of the reservoir encountered at each well point. In this embodiment, the number of wells n in the study area is assumed to be 14, and the sum of the thicknesses of the logging interpretation results at each well point is considered. The thickness is 23.94m, and the actual average thickness H1 is 1.71m.
[0059] Table 1. Sampling area and relative error for different planar grid sizes.
[0060] Grid size d (m) Sampling area A2 (km 2 )]]> Relative error ε A (%)]] 100 1.330 -20.36 90 1.507 -9.78 80 1.370 -17.99 70 1.416 -15.20 60 1.472 -11.83 50 1.498 -10.33 40 1.491 -10.71 30 1.510 -9.57 20 1.520 -9.01 10 1.540 -7.81
[0061] S2.2 Different vertical grid sizes h were used to sample the interpretation conclusions of reservoirs and non-reservoirs at each well point, and the average vertical grid number N of the sampled geological bodies was statistically analyzed. H ,like Figure 3 As shown.
[0062] The formula for calculating the average number of grid cells in the vertical direction is:
[0063]
[0064] Where, N i N is the vertical grid number of each well point; n is the total number of well points; H It is the average number of grid cells in the vertical direction.
[0065] S2.3 Calculate the average reservoir thickness obtained from sampling based on the longitudinal average grid number.
[0066] The formula for calculating the average reservoir thickness is as follows:
[0067]
[0068] in, is the calculated average reservoir thickness; h is the vertical dimension of a single grid. In this embodiment, taking h = 0.6m as an example, the sum of the vertical grid numbers of the geological body sampled from each well point is 42, therefore the average vertical grid number N is... H =42 / 14=3, longitudinal average thickness H2=3×0.6=1.8m.
[0069] S2.4 Calculate the true average thickness of the reservoir With the calculated average reservoir thickness Error ε H Plot the curve of the error of reservoir average thickness as a function of vertical grid size h, and use it as the preferred curve for vertical grid size.
[0070] Error ε of reservoir average thickness H The calculation formula is:
[0071]
[0072] Where, ε H It represents the error in the average thickness of the reservoir.
[0073] In this embodiment, different vertical grid sizes h and corresponding average sampling thickness H2 and relative error ε H As shown in Table 2, the preferred curve for the obtained planar mesh size is as follows. Figure 4 As shown.
[0074] Table 2. Sampling thickness and relative error for different longitudinal grid sizes.
[0075] Grid size h (m) Sampling thickness H2 (m) Relative error ε H (%)]] 1 2.00 16.96 0.9 2.69 57.89 0.8 2.40 40.35 0.7 1.40 -18.12 0.6 1.79 5.26 0.5 2.00 16.96 0.4 2.00 16.96 0.3 2.10 22.81 0.2 1.99 16.95 0.1 2.00 16.96
[0076] S3 selects planar grid dimensions with errors less than a threshold from the planar grid dimension optimization curve, and selects vertical grid dimensions with errors less than a threshold from the vertical grid dimension optimization curve. The errors of the selected planar grid dimensions and the selected vertical grid dimensions are then added pairwise to obtain the total error ε. 总 That is, ε 总 =ε A +ε H In this embodiment, the threshold is 10%. Error ε A The planar grid sizes corresponding to points whose absolute values are less than 10% are 30m, 20m, and 10m, respectively, with an error ε. HThe vertical grid size corresponding to points whose absolute value is less than 10% is 0.6m. The total error ε corresponding to different combinations of grid sizes is... A +ε H The number of grids is shown in Table 3.
[0077] Table 3. Total sampling error and number of grids corresponding to different combinations of planar and longitudinal grid sizes.
[0078]
[0079] S4 selects combinations whose total error is still less than the threshold to generate a candidate mesh size set.
[0080] S5 selects the combination of mesh sizes with the fewest total meshes from the candidate mesh size set as the optimal mesh size combination.
[0081] The combination of grid sizes is represented as follows:
[0082] N t =N A ×N H ×n
[0083] Where, N t It is a combination of grid sizes; N A N is the number of planar grids of a geological body. H is the average number of grid cells in the vertical direction; n is the total number of well points. In this embodiment, the total effective number of grid cells in the geological model is N = 181 × 3 × 14 = 2172. As shown in Table 3, the optimal grid size combination is: 30m for the planar grid and 0.6m for the vertical grid.
[0084] Example 2
[0085] This invention also discloses an optimal network size selection system for geological modeling of small-scale geological bodies, comprising:
[0086] The planar grid size optimization curve drawing module is used to compare the planar distribution of geological bodies with the planar gridding results, and draw the planar grid size optimization curve based on the comparison results;
[0087] The vertical grid size optimization curve plotting module is used to compare the reservoir interpretation conclusions of all well points in the geological body with the vertical gridding results, and plot the vertical grid size optimization curve based on the comparison results;
[0088] The total error calculation module is used to select planar grid sizes with errors less than a threshold from the preferred planar grid size curve, select longitudinal grid sizes with errors less than a threshold from the preferred longitudinal grid size curve, and add the errors of the selected planar grid sizes to the errors of the selected longitudinal grid sizes to obtain the total error.
[0089] The candidate set generation module is used to select combinations whose total error is still less than the threshold and generate a candidate mesh size set.
[0090] The grid size selection module is used to select the grid size combination with the fewest total grids from the candidate grid size set as the optimal grid size combination.
[0091] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention 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.
[0092] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. 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 illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.
[0093] 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.
[0094] 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.
[0095] 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 the present invention, but the protection scope of the present invention 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 the present invention should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be determined by the protection scope of the claims.
Claims
1. A method for selecting the optimal network size in geological modeling of small-scale geological bodies, characterized in that, Includes the following steps: The planar distribution of geological bodies is compared with the planar meshing results, and the optimal planar mesh size curve is plotted based on the comparison results; The reservoir interpretation conclusions of all well points in the geological body are compared with the vertical gridding results, and the optimal curve of vertical grid size is plotted based on the comparison results. Select a planar grid size with an error less than a threshold from the preferred planar grid size curve, and select a vertical grid size with an error less than a threshold from the preferred vertical grid size curve. Add the error of the planar grid size to the error of the vertical grid size to obtain the total error. Select combinations whose total error is still less than the threshold to generate a candidate mesh size set; select the mesh size combination with the fewest total meshes from the candidate mesh size set as the optimal mesh size combination.
2. The method for selecting the optimal network size for geological modeling of small-scale geological bodies as described in claim 1, characterized in that, The method for drawing the preferred curve for the planar grid size is as follows: Draw a planar distribution map of the geological bodies based on their seismic properties; The planar distribution map of the geological body was sampled using different planar grid sizes, and the number of planar grids sampled to the geological body was counted. Calculate the planar area of the geological body based on the number of planar grids. The error between the calculated actual planar area of a geological body and the calculated planar area of the geological body; Plot a curve showing the error of the planar area of the geological body as a function of the planar grid size, and use this curve as the preferred curve for the planar grid size.
3. The method for selecting the optimal network size for geological modeling of small-scale geological bodies as described in claim 2, characterized in that, The formula for calculating the planar area of the geological body is: A2=N A xd 2 Where A2 is the calculated planar area of the geological body; N A d is the number of planar grids of the geological body; d is the side length of a single planar grid.
4. The method for selecting the optimal network size for geological modeling of small-scale geological bodies as described in claim 3, characterized in that, The formula for calculating the error of the planar area of the geological body is as follows: Where A1 is the actual planar area of the geological body; ε A It is an error in the planar area of the geological body.
5. The method for selecting the optimal network size for geological modeling of small-scale geological bodies as described in claim 1, characterized in that, The method for drawing the preferred curve for the vertical grid size is as follows: Based on the reservoir interpretation conclusions of all well points within the geological body, the true average thickness of the reservoir is calculated. Different vertical grid sizes were used to sample the interpretation conclusions of reservoirs and non-reservoirs at each well point, and the average number of vertical grids sampled to the geological body was statistically analyzed. The average reservoir thickness obtained from the sampling is calculated based on the longitudinal average grid number. Calculate the error between the true average thickness of the reservoir and the calculated average thickness of the reservoir. Plot the curve of the error of the average thickness of the reservoir as a function of the longitudinal grid size, and use it as the preferred curve for the longitudinal grid size.
6. The method for selecting the optimal network size for geological modeling of small-scale geological bodies as described in claim 5, characterized in that, The formula for calculating the true average thickness of the reservoir is as follows: The formula for calculating the average number of grid cells in the vertical direction is: Where, N i n is the number of vertical grid points for each well point; n is the total number of well points. It is the true average thickness of the reservoir; H i It is the thickness of the reservoir encountered at each well point; N H It is the average number of grid cells in the vertical direction.
7. The method for selecting the optimal network size for geological modeling of small-scale geological bodies as described in claim 6, characterized in that, The formula for calculating the average reservoir thickness is as follows: in, is the calculated average reservoir thickness; h is the longitudinal dimension of a single grid.
8. The method for selecting the optimal network size for geological modeling of small-scale geological bodies as described in claim 7, characterized in that, The formula for calculating the error of the average reservoir thickness is as follows: Where, ε H It represents the error in the average thickness of the reservoir.
9. The method for selecting the optimal network size for geological modeling of small-scale geological bodies as described in claim 1, characterized in that, The combination of grid sizes is represented as follows: N t =N A ×N H ×n Where, N t It is a combination of grid sizes; N A N is the number of planar grids of a geological body. H is the average number of grid cells in the vertical direction; n is the total number of well points.
10. A system for selecting the optimal network size for geological modeling of small-scale geological bodies, characterized in that, include: The planar grid size optimization curve drawing module is used to compare the planar distribution of geological bodies with the planar gridding results, and draw the planar grid size optimization curve based on the comparison results; The vertical grid size optimization curve plotting module is used to compare the reservoir interpretation conclusions of all well points in the geological body with the vertical gridding results, and plot the vertical grid size optimization curve based on the comparison results; The total error calculation module is used to select planar grid sizes with errors less than a threshold from the preferred planar grid size curve, select longitudinal grid sizes with errors less than a threshold from the preferred longitudinal grid size curve, and add the errors of the selected planar grid sizes to the errors of the selected longitudinal grid sizes to obtain the total error. The candidate set generation module is used to select combinations whose total error is still less than the threshold and generate a candidate mesh size set. The grid size selection module is used to select the grid size combination with the fewest total grids from the candidate grid size set as the optimal grid size combination.