Three-dimensional rock core digital body preprocessing method and system

Abstract

The invention discloses a three-dimensional rock core digital body preprocessing method and system, and relates to the technical field of oil exploration and development. The method comprises the following steps: preprocessing a cylindrical rock core, cutting the cylindrical rock core into hexahedral rock cores, and quantitatively evaluating the similarity of attribute distribution before and after cutting under the condition of certain length-width ratio limitation so as to retain the distribution characteristics of rock core attributes; by implementing the method, boundary conditions can be constructed on six planes of a rock core digital body, rock physical properties in different directions are obtained through numerical simulation experiments in different directions, anisotropy analysis is carried out, and the analysis cost of multi-direction coring and CT scanning is saved.

Description

Technical Field

[0001] The invention discloses a three-dimensional rock core digital body preprocessing method and a system thereof, and relates to the technical field of petroleum exploration and development. Background Art

[0002] In the prior art, the processing method of the three-dimensional core digital body generally uses the digital core technology based on CT scanning imaging to obtain the three-dimensional core image, and the microstructure of the core can be characterized through image analysis and micro-scale simulation to achieve the construction of the three-dimensional digital core. Based on the constructed three-dimensional core digital body, numerical simulation experiments can replace traditional physical property experiments and be used to study the seepage, thermal conduction, electrical conduction and other characteristics of rocks, thereby obtaining rock physical properties such as permeability, thermal conductivity, and resistivity.

[0003] The physical properties of rocks are usually anisotropic, and anisotropic analysis requires characterization of rock properties in different directions. However, when conducting numerical simulation experiments on digital cores, boundary conditions are usually constructed on the two bottom surfaces of cylindrical cores, and only rock properties in a single direction (core axial direction) can be obtained through axial simulation experiments.

[0004] At present, the 3D core digital volume preprocessing method has the following shortcomings:

[0005] (1) The preprocessing process of 3D core digital cutting is ignored. In many current studies, digital cores are not cut, and only physical properties that are not affected by spatial directions are analyzed, or only core axial numerical simulation experiments are performed to obtain rock properties in a single direction. If digital core cutting is not performed, it is impossible to fully utilize digital core data to perform anisotropic analysis of rock properties, wasting the advantage of digital core images that can be reused without destroying the core structure and properties.

[0006] (2) There is a lack of scientific methods to effectively cut the three-dimensional core digital volume. By observing the core image or specifying the cutting range of the digital volume, it is impossible to ensure that the obtained attribute distribution is similar to that of the cylindrical core before cutting. The distribution of core attributes such as porosity and permeability reflects the heterogeneity of the rock to a certain extent. By observing the CT scan image or the three-dimensional attribute distribution with the naked eye, only the core area affected by the scan edge effect can be excluded, and the heterogeneity of the core digital volume before and after cutting cannot be quantitatively evaluated. Summary of the invention

[0007] In view of the problems of the prior art, the present invention provides a three-dimensional core digital body preprocessing method and system thereof, and the technical solution adopted is:

[0008] In a first aspect, a three-dimensional core digital volume preprocessing method is provided, the method comprising:

[0009] Get the grid information of the core digital volume and a bunch of arrays of original core attributes;

[0010] According to the stack of arrays of the original core attributes, the grid data marked as the external area is excluded to obtain a one-dimensional array of effective core attributes of the effective area of ​​the core digital body;

[0011] Perform a normal distribution test on the one-dimensional array of effective core attributes to determine characteristic parameters of the one-dimensional array of effective core attributes;

[0012] Calculating according to the characteristic parameters of the one-dimensional array of effective core attributes, obtaining characteristic parameter values ​​of the attribute distribution before the core digital body is cut;

[0013] According to the grid information, converting the original one-dimensional array of core attributes into a three-dimensional array of core attributes;

[0014] Determining a core cutting boundary according to the three-dimensional array of core attributes;

[0015] Cutting is performed according to the core cutting boundary, obtaining a three-dimensional array of hexahedral core attributes after cutting and calculating characteristic parameter values, thereby obtaining characteristic parameter values ​​of the attribute distribution of the core digital body after cutting;

[0016] By comparing the characteristic parameter values ​​of the attribute distribution before the core digital body is cut with the characteristic parameter values ​​of the attribute distribution after the core digital body is cut, the error of the characteristic parameter is calculated, and the cutting method with the smallest sum of the errors is selected as the optimal cutting method.

[0017] In some implementations, performing a normal distribution test on the one-dimensional array of effective core attributes to determine characteristic parameters of the one-dimensional array of effective core attributes includes:

[0018] According to the one-dimensional array of core attributes, a normal distribution test is performed by a chi-square goodness-of-fit test method or a Jacques-Berra test method;

[0019] The characteristic parameters of the one-dimensional array of core attributes are set.

[0020] In some implementations, determining a core cutting boundary according to the three-dimensional array of core attributes includes:

[0021] According to the three-dimensional array of core attributes, any single-layer section of the core is retrieved, four boundaries of core cutting are determined by searching in each direction, and a cutting method is obtained according to the four boundaries.

[0022] In some implementations, cutting is performed according to the core cutting boundary, a three-dimensional array of hexahedral core attributes after cutting is obtained, and characteristic parameter values ​​are calculated to obtain characteristic parameter values ​​of the attribute distribution of the core digital body after cutting, including:

[0023] According to the cutting method, the aspect ratio of the hexahedral core digital volume after cutting is set;

[0024] If the cutting method satisfies the aspect ratio, the set characteristic parameter value is calculated as the characteristic parameter value of the attribute distribution after the core digital body is cut;

[0025] If the cutting method does not satisfy the aspect ratio, any single-layer section of the core is retrieved again according to the three-dimensional array of core attributes.

[0026] In some implementations, setting characteristic parameters of the one-dimensional array of core attributes includes:

[0027] If the one-dimensional array of core attributes conforms to a normal distribution, the characteristic parameters are set as a mean and a standard deviation;

[0028] If the one-dimensional array of core attributes does not conform to a normal distribution, the characteristic parameters are set to mean, standard deviation, kurtosis and skewness.

[0029] In a second aspect, an embodiment of the present invention provides a three-dimensional core digital body preprocessing system, the system comprising:

[0030] Information acquisition module, used to obtain grid information of core digital volume and a stack of arrays of original core attributes;

[0031] A data screening module is used to exclude grid data marked as external areas according to a stack of arrays of original core attributes, and obtain a one-dimensional array of effective core attributes in the effective area of ​​the core digital body;

[0032] A data verification module, used for performing a normal distribution test based on the one-dimensional array of effective core attributes to determine characteristic parameters of the one-dimensional array of effective core attributes;

[0033] A parameter calculation module, used to calculate according to the characteristic parameters of the one-dimensional array of effective core attributes, and obtain the characteristic parameter values ​​of the attribute distribution before the core digital body is cut;

[0034] An array conversion module, used for converting the original one-dimensional array of core attributes into a three-dimensional array of core attributes according to the grid information;

[0035] A boundary confirmation module, used for determining the core cutting boundary according to the three-dimensional array of core attributes;

[0036] A boundary processing module is used to perform cutting according to the core cutting boundary, obtain a three-dimensional array of hexahedral core properties after cutting and calculate characteristic parameter values, and obtain characteristic parameter values ​​of the property distribution of the core digital body after cutting;

[0037] The parameter processing module is used to calculate the error of the characteristic parameters according to the comparison between the characteristic parameter values ​​of the attribute distribution of the core digital body before cutting and the characteristic parameter values ​​of the attribute distribution of the core digital body after cutting, and select the cutting method with the smallest sum of the errors as the optimal cutting method.

[0038] In some implementations, the data verification module includes:

[0039] A normal distribution verification module, used for performing a normal distribution test by a chi-square goodness-of-fit test method or a Jacques-Berra test method according to the one-dimensional array of core attributes;

[0040] The parameter setting module is used to set the characteristic parameters of the one-dimensional array of core attributes.

[0041] In some implementations, it is characterized in that the boundary confirmation module includes:

[0042] According to the three-dimensional array of core attributes, any single-layer section of the core is retrieved, four boundaries of core cutting are determined by searching in each direction, and a cutting method is obtained according to the four boundaries.

[0043] In some implementations, the boundary processing module includes:

[0044] A ratio setting module, used for setting the aspect ratio of the hexahedral core digital volume after cutting according to the cutting method;

[0045] A cutting calculation module, used for calculating the set characteristic parameter value as the characteristic parameter value of the attribute distribution after the core digital body is cut if the cutting method satisfies the aspect ratio;

[0046] The section search module is used to search for any single-layer section of the core again according to the three-dimensional array of core attributes if the cutting method does not satisfy the aspect ratio.

[0047] In some implementations, the parameter setting module includes:

[0048] A first parameter module, for setting the characteristic parameters to mean and standard deviation if the one-dimensional array of core attributes conforms to a normal distribution;

[0049] The second parameter module is used to set the characteristic parameters to mean, standard deviation, kurtosis and skewness if the one-dimensional array of core attributes does not conform to the normal distribution.

[0050] In a third aspect, an embodiment of the present invention provides an electronic device, comprising a memory and a processor, wherein the memory is used to store one or more computer instructions, wherein when the one or more computer instructions are executed by the processor, the method described in the first aspect above is implemented.

[0051] In a fourth aspect, an embodiment of the present invention provides a computer storage medium, wherein the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, it is used to implement the method described in the first aspect.

[0052] One or more embodiments of the present invention can bring at least the following beneficial effects:

[0053] The present invention provides a three-dimensional core digital body preprocessing method, which preprocesses a cylindrical core and cuts it into a hexahedral core. Under the condition of a certain aspect ratio, the similarity of the attribute distribution before and after cutting is quantitatively evaluated to retain the distribution characteristics of the core attributes. By implementing this method, boundary conditions can be constructed on six planes of the core digital body, and rock properties in different directions can be obtained through numerical simulation experiments in different directions and anisotropy analysis can be performed, thereby saving the analysis costs of multi-directional coring and CT scanning. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0055] Figure 1 It is a flow chart of a three-dimensional core digital body preprocessing method provided by an embodiment of the present invention;

[0056] Figure 2 It is an implementation flow chart of a three-dimensional core digital body preprocessing method provided by an embodiment of the present invention;

[0057] Figure 3 is a porosity distribution histogram before core digital body cutting provided by an embodiment of the present invention;

[0058] Figure 4 is a schematic diagram of the porosity distribution of a top single-layer cross section of a core digital body before cutting provided by an embodiment of the present invention;

[0059] Figure 5 is a porosity distribution histogram after the core digital body is cut according to an embodiment of the present invention;

[0060] Figure 6 This is a schematic diagram of the optimal cutting boundary of a core digital volume provided by an embodiment of the present invention;

[0061] Figure 7 Schematic diagram of porosity distribution of a top single-layer cross section after core digital body cutting provided by an embodiment of the present invention;

[0062] Figure 8 It is a block diagram of a three-dimensional core digital body preprocessing system provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0063] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. The components of the embodiments of the present invention generally described and shown in the drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents the selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making creative work belong to the scope of protection of the present invention.

[0064] Embodiment 1:

[0065] Figure 1 A flow chart of a three-dimensional core digital body preprocessing method is shown in FIG. Figure 1 As shown, the three-dimensional core digital body preprocessing method provided in this embodiment includes:

[0066] S1 obtains the grid information of the core digital body and a bunch of arrays of original core attributes;

[0067] S2 obtains a one-dimensional array of effective core attributes in the effective area of ​​the core digital body according to a stack of arrays of the original core attributes, excluding the grid data marked as the external area;

[0068] S3 performs a normal distribution test according to the one-dimensional array of effective core attributes to determine characteristic parameters of the one-dimensional array of effective core attributes;

[0069] S4 calculates according to the characteristic parameters of the one-dimensional array of effective core attributes to obtain characteristic parameter values ​​of the attribute distribution before the core digital body is cut;

[0070] S5, converting the original one-dimensional array of core attributes into a three-dimensional array of core attributes according to the grid information;

[0071] S6 determines the core cutting boundary according to the three-dimensional array of core attributes;

[0072] S7 performs cutting according to the core cutting boundary, obtains a three-dimensional array of hexahedral core attributes after cutting, and calculates characteristic parameter values ​​to obtain characteristic parameter values ​​of the attribute distribution of the core digital body after cutting;

[0073] S8: Calculate the error of the characteristic parameter by comparing the characteristic parameter value of the attribute distribution of the core digital body before cutting with the characteristic parameter value of the attribute distribution of the core digital body after cutting, and select the cutting method with the smallest sum of the errors as the optimal cutting method.

[0074] According to S1, the grid scale and grid division information of the core digital volume are obtained. The three-dimensional space of the core digital volume is usually divided into regular hexahedral grids as voxels, including the cylindrical core (valid) area and the external (invalid) area. The grid division of the core digital volume refers to the number of grids in three directions, the number of grids in the x-axis direction is nx, the number of grids in the y-axis direction is ny, and the number of grids in the z-axis direction is nz. The grid scale of the three-dimensional core digital volume is nx×ny×nz, and the grid scale of the single-layer core section is nx×ny;

[0075] The voxel size information of the core digital volume is obtained, that is, the size information of each hexahedral grid in the three-dimensional space of the core digital volume, the grid size in the x-axis direction is dx, the grid size in the y-axis direction is dy, and the grid size in the z-axis direction is dz.

[0076] According to S2, the core digital volume file is obtained and read, including the digital volume of attributes such as porosity and permeability, and the digital volume of phase markers. Each digital volume is a separate file, usually in RAW format, and the read attribute volume or phase marker volume is a one-dimensional array arranged according to a certain rule;

[0077] According to the one-dimensional array of the obtained core digital volume, the grid data of the external (invalid) area is excluded by the voxel-by-voxel retrieval and judgment method, and only the grid data of the cylindrical core (valid) area is retained to obtain the one-dimensional array of the cylindrical core attributes. There are two ways of retrieval and judgment. One is that the obtained digital volume includes the phase marker volume. In this case, the phase marker value of the grid in the external area is a specific value. The judgment condition at this time is that the retrieved grid phase marker value is equal to the external area phase marker value; the other is that the obtained digital volume only has the attribute volume and no phase marker volume. At this time, the judgment condition is that the retrieved grid attribute value is equal to 0.

[0078] According to S3, a normal distribution test is performed according to the one-dimensional array of effective core attributes to determine characteristic parameters of the one-dimensional array of effective core attributes;

[0079] Further, a normal distribution test is performed according to the one-dimensional array of core attributes in S3 to determine characteristic parameters of the one-dimensional array of core attributes, including:

[0080] S31, according to the one-dimensional array of core attributes, performing a normal distribution test by a chi-square goodness of fit test method or a Jacques-Berra test method;

[0081] S32 sets characteristic parameters of the one-dimensional array of core attributes.

[0082] Further, S32 includes:

[0083] S321 If the one-dimensional array of core attributes conforms to a normal distribution, the characteristic parameters are set as a mean and a standard deviation;

[0084] S322 If the one-dimensional array of core attributes does not conform to a normal distribution, the characteristic parameters are set to mean, standard deviation, kurtosis and skewness.

[0085] According to S4, for a pile of cylindrical core attribute data obtained in S2, the characteristic parameters specified in S3 are calculated, which are the characteristic parameters of the attribute distribution before the core digital body is cut;

[0086] The mean calculation formula of core properties is:

[0087]

[0088] In the formula, x i is the i-th element of the one-dimensional array of core attributes, and N is the length of the one-dimensional array of core attributes;

[0089] The standard deviation of core properties is calculated as:

[0090]

[0091] The kurtosis calculation formula of core attributes is:

[0092] The skewness calculation formula of core attributes is:

[0093]

[0094] According to S5, based on the grid division information of the core digital volume obtained in S1, according to the arrangement rule of the core digital volume, the stack of digital volume arrays read in S2 is converted into a three-dimensional array. The arrangement rule of the core digital volume is usually to arrange the voxels in the order of first the x direction, then the y direction, and finally the z direction.

[0095] According to S6, determining a core cutting boundary according to the three-dimensional array of core attributes includes:

[0096] Retrieve any single-layer section of the core according to the three-dimensional array of core attributes, determine four boundaries of core cutting by searching in each direction, and obtain a cutting method according to the four boundaries;

[0097] S61 selects any single layer (corresponding to the same z value) section of the core for the three-dimensional array of digital volumes of the core obtained in S5, searches for the attribute value or phase marker value of any row (corresponding to the same y value) of the section, and records the column numbers (x values) of the first and end grids of the valid area of ​​the row as start_x and end_x respectively according to the search judgment criteria of S2.

[0098] S62 uses the column number start_x of the start grid of the effective area of ​​any row of the core section (corresponding to the same y value) obtained in S61 as the first boundary of the core cutting, retrieves the attribute value or phase marker value of the column, and records the row numbers (y values) of the start and end grids of the effective area of ​​the column as start_y1 and end_y1 respectively according to the retrieval judgment criteria of S2;

[0099] S63, based on the column number end_x of the end grid of the effective area of ​​any row of the core section (corresponding to the same y value) obtained in S61, takes this column as the second boundary of the core cutting, retrieves the attribute value or phase marker value of the column, and records the row numbers (y values) of the first and end grids of the effective area of ​​the column as start_y2 and end_y2 respectively according to the retrieval judgment criteria of S2;

[0100] S64 compares the row number start_y1 of the first end grid of the effective boundary area obtained in S62 with the row number start_y2 of the second end grid of the effective boundary area obtained in S63, assigns the larger value to start_y, and uses the row corresponding to the start_y value as the third boundary of core cutting;

[0101] S65 compares the row number end_y1 of the end grid of the first boundary effective area obtained in S62 with the row number end_y2 of the end grid of the second boundary effective area obtained in S63, assigns the smaller value to end_y, and uses the row corresponding to the end_y value as the fourth boundary of core cutting.

[0102] According to S7, the core is cut according to the core cutting boundary, a three-dimensional array of hexahedral core attributes after cutting is obtained, and characteristic parameter values ​​are calculated to obtain characteristic parameter values ​​of the attribute distribution of the core digital body after cutting, including:

[0103] S71, based on the three-dimensional array of core attribute volumes obtained in S5, applies the four boundaries of core cutting obtained in steps S62 to S65 to each single-layer core section, cuts the core digital volume (including the cylindrical core area) into a hexahedral core digital volume, and obtains a three-dimensional array of core attribute volumes after cutting;

[0104] S72 sets the maximum length-to-width ratio of the hexahedral core digital volume after cutting to ar_max, applies the method of S61 to search each row of the core section, and repeats steps S61 to S65 to obtain a cutting method that meets the length-to-width ratio restriction condition;

[0105] S73 converts the three-dimensional array of the core attribute body after cutting obtained in S71 into a one-dimensional array according to the arrangement rule of the core digital body described in S5 for the cutting method that meets the aspect ratio restriction condition obtained in S72, and calculates the characteristic parameters specified in S32 for the one-dimensional array using the formula of S4, which are the characteristic parameters of the attribute distribution of the core digital body after cutting.

[0106] According to S8, for the cutting method that meets the aspect ratio restriction condition obtained in S72, the characteristic parameters of the attribute distribution of the core digital body calculated in S4 and S73 before and after cutting are compared, and the relative error of each specified calculated characteristic parameter is calculated, and the cutting method with the smallest sum of the relative errors of all specified characteristic parameters is obtained as the optimal cutting method;

[0107] The calculation formula of the relative error of the attribute distribution characteristic parameters before and after the core digital body cutting is:

[0108]

[0109] Where x1 is the characteristic parameter of the attribute distribution before the core digital body is cut, and x2 is the characteristic parameter of the attribute distribution after the core digital body is cut.

[0110] Embodiment 2:

[0111] Based on the first embodiment, Figure 2 The implementation flow chart of the method of the present invention is shown, and the three-dimensional core digital body preprocessing method of the method of the present invention is applied to process the core including the phase marker body and the porosity body, and the optimal cutting method is obtained to cut the cylindrical core into a hexahedral core:

[0112] Obtain the grid scale, mesh division and voxel size information of the core digital volume.

[0113] The one-dimensional array of the core phase marker and porosity body is read, and the grid data of the external (invalid) area is excluded by searching each voxel and using the phase marker value as the judgment condition to obtain the one-dimensional array of porosity of the cylindrical core (valid) area.

[0114] For the one-dimensional array of the obtained cylindrical core porosity, the normal distribution test was performed using the chi-square goodness of fit test method or the Jacques-Berra test method. The results showed that the cylindrical core porosity did not conform to the normal distribution at a significance level of 0.05. Therefore, the characteristic parameters specified for characterizing the core porosity distribution are mean, standard deviation, kurtosis and skewness.

[0115] Based on the one-dimensional array of cylindrical core porosity, characteristic parameters are calculated. The mean of the porosity distribution before the core digital volume cutting is 0.2171, the standard deviation is 0.0978, the kurtosis is 5.8464, and the skewness is 1.0824. The histogram of the porosity distribution before the core digital volume cutting is shown in Figure 3 shown.

[0116] Based on the one-dimensional array of the read core phase marker body and porosity body, that is, the one-dimensional array without excluding the external (invalid) area grid data, the one-dimensional array is converted into a three-dimensional array according to the arrangement rules of the core digital body.

[0117] Based on the obtained three-dimensional array of the core digital volume, the top single-layer section of the core is selected, and the four boundaries of the core cutting are determined by searching in each direction to obtain all possible cutting methods. The porosity distribution of the top single-layer section before the core digital volume cutting is shown in the figure below: Figure 4 shown.

[0118] The maximum aspect ratio of the hexahedral core digital volume after cutting is set to 1.1. For each cutting method that satisfies the aspect ratio less than 1.1, the three-dimensional array of the core porosity volume after cutting is converted into a one-dimensional array, and its characteristic parameters are calculated and compared with the characteristic parameters before cutting. The relative error of the characteristic parameters is calculated, and the cutting method with the smallest sum of relative errors of the characteristic parameters is selected as the optimal cutting method.

[0119] According to the optimal cutting method of the core digital body, the mean of the porosity distribution after the core digital body cutting is 0.2202, the standard deviation is 0.0957, the kurtosis is 6.1440, and the skewness is 1.1322. The histogram of the porosity distribution after the core digital body cutting is shown in Figure 5 As shown in Figure 2, the cutting boundary of the core digital volume is as follows: Figure 6 The porosity distribution of the top single-layer section after the core digital body is cut is as follows: Figure 7 shown.

[0120] Embodiment three:

[0121] Figure 8 A schematic diagram of the structure of a three-dimensional core digital body preprocessing system is shown in FIG. Figure 8 As shown, the three-dimensional core digital body preprocessing system provided in this embodiment includes:

[0122] Information acquisition module, used to obtain grid information of core digital volume and a stack of arrays of original core attributes;

[0123] A data screening module is used to exclude grid data marked as external areas according to a stack of arrays of original core attributes, and obtain a one-dimensional array of effective core attributes in the effective area of ​​the core digital body;

[0124] A data verification module, used for performing a normal distribution test based on the one-dimensional array of effective core attributes to determine characteristic parameters of the one-dimensional array of effective core attributes;

[0125] A parameter calculation module, used to calculate according to the characteristic parameters of the one-dimensional array of effective core attributes, and obtain the characteristic parameter values ​​of the attribute distribution before the core digital body is cut;

[0126] An array conversion module, used for converting the original one-dimensional array of core attributes into a three-dimensional array of core attributes according to the grid information;

[0127] A boundary confirmation module, used for determining the core cutting boundary according to the three-dimensional array of core attributes;

[0128] A boundary processing module is used to perform cutting according to the core cutting boundary, obtain a three-dimensional array of hexahedral core properties after cutting and calculate characteristic parameter values, and obtain characteristic parameter values ​​of the property distribution of the core digital body after cutting;

[0129] The parameter processing module is used to calculate the error of the characteristic parameters according to the comparison between the characteristic parameter values ​​of the attribute distribution of the core digital body before cutting and the characteristic parameter values ​​of the attribute distribution of the core digital body after cutting, and select the cutting method with the smallest sum of the errors as the optimal cutting method.

[0130] In some implementations, the data verification module includes:

[0131] A normal distribution verification module, used for performing a normal distribution test by a chi-square goodness-of-fit test method or a Jacques-Berra test method according to the one-dimensional array of core attributes;

[0132] The parameter setting module is used to set the characteristic parameters of the one-dimensional array of core attributes.

[0133] In some implementations, it is characterized in that the boundary confirmation module includes:

[0134] According to the three-dimensional array of core attributes, any single-layer section of the core is retrieved, four boundaries of core cutting are determined by searching in each direction, and a cutting method is obtained according to the four boundaries.

[0135] In some implementations, the boundary processing module includes:

[0136] A ratio setting module, used for setting the aspect ratio of the hexahedral core digital volume after cutting according to the cutting method;

[0137] A cutting calculation module, used for calculating the set characteristic parameter value as the characteristic parameter value of the attribute distribution after the core digital body is cut if the cutting method satisfies the aspect ratio;

[0138] The section search module is used to search for any single-layer section of the core again according to the three-dimensional array of core attributes if the cutting method does not satisfy the aspect ratio.

[0139] In some implementations, the parameter setting module includes:

[0140] A first parameter module, for setting the characteristic parameters to mean and standard deviation if the one-dimensional array of core attributes conforms to a normal distribution;

[0141] The second parameter module is used to set the characteristic parameters to mean, standard deviation, kurtosis and skewness if the one-dimensional array of core attributes does not conform to the normal distribution.

[0142] Embodiment 4:

[0143] This embodiment further provides an electronic device, including a memory and a processor, wherein the memory is used to store one or more computer instructions, wherein the one or more computer instructions implement the method of embodiment 1 when executed by the processor;

[0144] In practical applications, the processor can be an application specific integrated circuit (ASIC), a digital signal processor (DSP), a digital signal processing device (DSPD), a programmable logic device (PLD), a field programmable gate array (FPGA), a controller, a microcontroller unit (MCU), a microprocessor or other electronic components to execute the methods in the above embodiments.

[0145] The method implemented in this embodiment includes:

[0146] S1 obtains the grid information of the core digital body and a bunch of arrays of original core attributes;

[0147] S2 obtains a one-dimensional array of effective core attributes in the effective area of ​​the core digital body according to a stack of arrays of the original core attributes, excluding the grid data marked as the external area;

[0148] S3 performs a normal distribution test according to the one-dimensional array of effective core attributes to determine characteristic parameters of the one-dimensional array of effective core attributes;

[0149] S4 calculates according to the characteristic parameters of the one-dimensional array of effective core attributes to obtain characteristic parameter values ​​of the attribute distribution before the core digital body is cut;

[0150] S5, converting the original one-dimensional array of core attributes into a three-dimensional array of core attributes according to the grid information;

[0151] S6 determines the core cutting boundary according to the three-dimensional array of core attributes;

[0152] S7 performs cutting according to the core cutting boundary, obtains a three-dimensional array of hexahedral core attributes after cutting, and calculates characteristic parameter values ​​to obtain characteristic parameter values ​​of the attribute distribution of the core digital body after cutting;

[0153] S8: Calculate the error of the characteristic parameter by comparing the characteristic parameter value of the attribute distribution of the core digital body before cutting with the characteristic parameter value of the attribute distribution of the core digital body after cutting, and select the cutting method with the smallest sum of the errors as the optimal cutting method.

[0154] Embodiment five:

[0155] This embodiment further provides a computer storage medium, wherein the computer-readable storage medium stores a computer program, and when the computer program is executed by one or more processors, the method of the first embodiment is implemented;

[0156] Among them, the computer-readable storage medium can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as static random access memory (SRAM), electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EPROM), programmable read-only memory (PROM), read-only memory (ROM), magnetic storage, flash memory, disk or optical disk.

[0157] The method implemented in this embodiment includes:

[0158] S1 obtains the grid information of the core digital body and a bunch of arrays of original core attributes;

[0159] S2 obtains a one-dimensional array of effective core attributes in the effective area of ​​the core digital body according to a stack of arrays of the original core attributes, excluding the grid data marked as the external area;

[0160] S3 performs a normal distribution test according to the one-dimensional array of effective core attributes to determine characteristic parameters of the one-dimensional array of effective core attributes;

[0161] S4 calculates according to the characteristic parameters of the one-dimensional array of effective core attributes to obtain characteristic parameter values ​​of the attribute distribution before the core digital body is cut;

[0162] S5, converting the original one-dimensional array of core attributes into a three-dimensional array of core attributes according to the grid information;

[0163] S6 determines the core cutting boundary according to the three-dimensional array of core attributes;

[0164] S7 performs cutting according to the core cutting boundary, obtains a three-dimensional array of hexahedral core attributes after cutting, and calculates characteristic parameter values ​​to obtain characteristic parameter values ​​of the attribute distribution of the core digital body after cutting;

[0165] S8: Calculate the error of the characteristic parameter by comparing the characteristic parameter value of the attribute distribution of the core digital body before cutting with the characteristic parameter value of the attribute distribution of the core digital body after cutting, and select the cutting method with the smallest sum of the errors as the optimal cutting method.

[0166] In the several embodiments provided in the embodiments of the present invention, it should be understood that the disclosed system and method can also be implemented in other ways. The system and method embodiments described above are merely illustrative.

[0167] It should be noted that, in this article, the terms "first", "second", etc. in the specification and claims of this application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. The terms "comprise", "include" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprises a..." does not exclude the presence of other identical elements in the process, method, article or device including the element.

[0168] Although the embodiments disclosed in the present invention are as above, the above contents are only embodiments adopted for facilitating the understanding of the present invention and are not intended to limit the present invention. Any technician in the technical field to which the present invention belongs can make any modifications and changes in the form and details of the implementation without departing from the spirit and scope disclosed in the present invention, but the patent protection scope of the present invention shall still be subject to the scope defined in the attached claims.

Claims

1. A three-dimensional core digital volume preprocessing method, characterized in that: The method comprises: Get the grid information of the core digital volume and a bunch of arrays of original core attributes; According to the stack of arrays of the original core attributes, the grid data marked as the external area is excluded to obtain a one-dimensional array of effective core attributes of the effective area of ​​the core digital body; Perform a normal distribution test on the one-dimensional array of effective core attributes to determine characteristic parameters of the one-dimensional array of effective core attributes; Calculating according to the characteristic parameters of the one-dimensional array of effective core attributes, obtaining characteristic parameter values ​​of the attribute distribution before the core digital body is cut; According to the grid information, converting the original one-dimensional array of core attributes into a three-dimensional array of core attributes; Determining a core cutting boundary according to the three-dimensional array of core attributes; Cutting is performed according to the core cutting boundary, obtaining a three-dimensional array of hexahedral core attributes after cutting and calculating characteristic parameter values, thereby obtaining characteristic parameter values ​​of the attribute distribution of the core digital body after cutting; By comparing the characteristic parameter values ​​of the attribute distribution before the core digital body is cut with the characteristic parameter values ​​of the attribute distribution after the core digital body is cut, the error of the characteristic parameter is calculated, and the cutting method with the smallest sum of the errors is selected as the optimal cutting method.

2. The method according to claim 1, characterized in that: Performing a normal distribution test according to the one-dimensional array of effective core attributes to determine characteristic parameters of the one-dimensional array of effective core attributes includes: According to the one-dimensional array of core attributes, a normal distribution test is performed by a chi-square goodness-of-fit test method or a Jacques-Berra test method; The characteristic parameters of the one-dimensional array of core attributes are set.

3. The method according to claim 1, characterized in that Determining a core cutting boundary according to the three-dimensional array of core attributes includes: According to the three-dimensional array of core attributes, any single-layer section of the core is retrieved, four boundaries of core cutting are determined by searching in each direction, and a cutting method is obtained according to the four boundaries.

4. The method according to claim 3, characterized in that: Cutting is performed according to the core cutting boundary, obtaining a three-dimensional array of hexahedral core attributes after cutting and calculating characteristic parameter values, and obtaining characteristic parameter values ​​of the attribute distribution of the core digital body after cutting, including: According to the cutting method, the aspect ratio of the hexahedral core digital volume after cutting is set; If the cutting method satisfies the aspect ratio, the set characteristic parameter value is calculated as the characteristic parameter value of the attribute distribution after the core digital body is cut; If the cutting method does not satisfy the aspect ratio, any single-layer section of the core is retrieved again according to the three-dimensional array of core attributes.

5. The method according to claim 2, characterized in that: The characteristic parameters of a stack of arrays of core attributes are set, including: If the one-dimensional array of core attributes conforms to a normal distribution, the characteristic parameters are set as a mean and a standard deviation; If the one-dimensional array of core attributes does not conform to a normal distribution, the characteristic parameters are set to mean, standard deviation, kurtosis and skewness.

6. A three-dimensional core digital volume preprocessing system, characterized in that: The system comprises: Information acquisition module, used to obtain grid information of core digital volume and a stack of arrays of original core attributes; A data screening module is used to exclude grid data marked as external areas according to a stack of arrays of original core attributes, and obtain a one-dimensional array of effective core attributes in the effective area of ​​the core digital body; A data verification module, used for performing a normal distribution test based on the one-dimensional array of effective core attributes to determine characteristic parameters of the one-dimensional array of effective core attributes; A parameter calculation module, used to calculate according to the characteristic parameters of the one-dimensional array of effective core attributes, and obtain the characteristic parameter values ​​of the attribute distribution before the core digital body is cut; An array conversion module, used for converting the original one-dimensional array of core attributes into a three-dimensional array of core attributes according to the grid information; A boundary confirmation module, used for determining the core cutting boundary according to the three-dimensional array of core attributes; A boundary processing module is used to perform cutting according to the core cutting boundary, obtain a three-dimensional array of hexahedral core properties after cutting and calculate characteristic parameter values, and obtain characteristic parameter values ​​of the property distribution of the core digital body after cutting; The parameter processing module is used to calculate the error of the characteristic parameters according to the comparison between the characteristic parameter values ​​of the attribute distribution of the core digital body before cutting and the characteristic parameter values ​​of the attribute distribution of the core digital body after cutting, and select the cutting method with the smallest sum of the errors as the optimal cutting method.

7. The system according to claim 6, characterized in that The data verification module comprises: A normal distribution verification module, used for performing a normal distribution test by a chi-square goodness of fit test method or a Jacques-Berra test method according to the one-dimensional array of core attributes; The parameter setting module is used to set the characteristic parameters of the one-dimensional array of core attributes.

8. The system according to claim 6, characterized in that The boundary confirmation module includes: According to the three-dimensional array of core attributes, any single-layer section of the core is retrieved, four boundaries of core cutting are determined by searching in each direction, and a cutting method is obtained according to the four boundaries.

9. An electronic device, characterized in that: The method comprises a memory and a processor, wherein the memory is used to store one or more computer instructions, wherein the one or more computer instructions, when executed by the processor, implement the method as described in any one of claims 1 to 5.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, it is used to implement the method as described in any one of claims 1 to 5.

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