A calculation method and device for rock radial resistivity testing and electronic equipment

Abstract

The present application provides a kind of rock radial resistivity test error calculation method, device and electronic equipment, by rock radial resistivity test error analysis, effectively estimate the accuracy of rock radial resistivity test.The method comprises: obtaining the resistivity true value under different texture conditions of blocky rock;The cylindrical model corresponding to the blocky rock is constructed, and a three-dimensional coordinate system is constructed, the length and diameter of the cylindrical model are determined according to the three-dimensional coordinate system;Determine the texture plane of the cylindrical model and the first plane in the three-dimensional space and the included angle between the projection of the texture on the first plane and the first coordinate axis;Obtain the simulated resistivity value of the cylindrical model under different texture conditions and calculate the relative error of rock radial resistivity under various texture conditions;According to the relative error of the cylindrical model under different texture conditions and the length, diameter and included angle, the rock radial resistivity test error value is obtained.

Description

Technical Field

[0001] This invention relates to the field of rock physics, and in particular to a method for calculating the error of radial resistivity testing of rock cores. Background Technology

[0002] Currently, there are many methods for measuring rock resistivity. Due to the complexity of rock structure, the measurement of rock resistivity is particularly complex. Therefore, physical analysis methods are often used to measure rock resistivity, such as the voltammetry, diode method, and multi-electrode method. However, measuring rock resistivity through physical analysis methods has problems such as low accuracy and the influence of the contact resistance of the measuring electrodes.

[0003] The invention patent "Resistivity Measurement Method, Apparatus and System (ZL201810567063.3, US20190369286A1)" proposed by He Jiahuan (2018) et al. is used to test the radial resistivity of rock cores. For details, please refer to Interpretation 2020, 8(4): T1071-1079. In this existing method, the isotropic structure of the rock is assumed. The radial resistivity of cylindrical samples commonly used in the oil and gas field is tested using a simple experimental device and the principle of complex variable functions. It has wide applicability for characterizing the radial resistivity of rocks. However, in actual practice, rocks are usually blocky structures with anisotropy. The principle of complex variable functions is based on the isotropic structure of rocks. Therefore, an effective method is needed to estimate the accuracy of this method for testing the radial resistivity of rocks. Summary of the Invention

[0004] This invention provides a method for calculating the error in the radial resistivity test of rocks. The method obtains the true resistivity of block rocks under different texture conditions and the simulated resistivity value of a cylindrical model. Based on these values, the relative error of the radial resistivity test is calculated. The radial resistivity test error is then determined based on the relative error value under different texture conditions. This method addresses the applicability of calculating the radial resistivity of cylindrical rock samples using complex variable functions in characterizing anisotropic rock resistivity. It estimates the accuracy of this radial resistivity test method or performs systematic error analysis. Based on the obtained relative error, it can determine whether the radial resistivity of cylindrical samples obtained using the complex variable function principle is accurate under different rock texture conditions, thus improving the practicality of this method for testing rock resistivity in the oil and gas field.

[0005] On one hand, this invention provides a method for calculating the error in testing the radial resistivity of rocks, comprising:

[0006] Obtain the true resistivity values ​​of blocky rocks under different texture conditions;

[0007] Construct a cylindrical model corresponding to the blocky rock and a three-dimensional spatial coordinate system, and determine the length and diameter of the cylindrical model based on the three-dimensional spatial coordinate system;

[0008] Determine the angle between the texture plane of the cylindrical model and the first plane in the three-dimensional space, and the angle between the projection of the texture onto the first plane and the first coordinate axis;

[0009] The simulated resistivity values ​​of the cylindrical model under different texture conditions were obtained, and the relative error of the radial resistivity of the rock under various texture conditions was calculated.

[0010] The radial resistivity test error value of the rock is obtained based on the relative error under different texture conditions of the cylindrical model, as well as the length, diameter, and included angle.

[0011] Optionally, obtain the true resistivity values ​​for different textures of the blocky rock, including:

[0012] The texture development of the blocky rock is obtained through physical analysis, and the blocky rock is layered according to the texture development.

[0013] Determine the resistivity, thickness, and area of ​​each rock layer under different texture conditions;

[0014] The true resistivity values ​​under different texture conditions were obtained by using different calculation methods.

[0015] Optionally, obtaining the simulated resistivity values ​​of the cylindrical model under the different texture conditions includes:

[0016] Determine the type of angle relationship between the projection of the texture onto the first plane and the first coordinate axis of the different texture planes of the cylindrical model in the three-dimensional space;

[0017] Based on the type of included angle relationship, different calculation methods are used to obtain the simulated resistivity values ​​of the cylindrical model under different texture conditions.

[0018] Optionally, different calculation methods can be used to obtain the simulated resistivity values ​​of the cylindrical model under different texture conditions, including:

[0019] The cylindrical model is divided into layers to obtain the resistivity of each layer; wherein the resistivity of each layer corresponds to the resistivity of each layer of the blocky rock.

[0020] The cylindrical model is divided into equal regions, and current is set to flow in from one end and out from the adjacent end.

[0021] A finite element mesh is established, and the potential distribution diagram of the cylindrical model is obtained through the current equation. The cylindrical model is then divided into equal parts.

[0022] The average current value on each section after division is read based on the results of the electric field numerical simulation.

[0023] Obtain simulated resistivity values ​​for cylindrical models under different texture conditions.

[0024] Optionally, the cylindrical model is divided into equal-sized blocks, with current flowing in from one end and out from the adjacent end, including:

[0025] The cylindrical model is divided into equal regions along the axis in a symmetrical manner.

[0026] The current is set to flow into one end of the equal area block and out the adjacent end; wherein the potential value at the boundary of the inflow end is the maximum value, the potential value on the opposite side is the minimum value, and there is no current value at the adjacent end and the boundary of the adjacent end.

[0027] Optionally, a finite element mesh is created, dividing the cylindrical model into equal parts, including:

[0028] Divide the cylindrical model into finite equal parts from top to bottom in any direction.

[0029] Optionally, calculate the relative error of rock radial resistivity under various texture conditions, including:

[0030] The relative error of the radial resistivity test of the rock is obtained based on the true resistivity value of the blocky rock under different texture conditions and the simulated resistivity value of the corresponding cylindrical model.

[0031] On one hand, embodiments of the present invention provide an apparatus for measuring the radial resistivity test error of rock cores, comprising:

[0032] The acquisition unit is used to acquire the true resistivity values ​​of blocky rocks under different texture conditions;

[0033] A construction unit is used to construct a cylindrical model corresponding to the blocky rock and to construct a three-dimensional spatial coordinate system. The length and diameter of the cylindrical model are determined according to the three-dimensional spatial coordinate system.

[0034] And the angle between the texture plane of the cylindrical model and the first plane in the three-dimensional space, and the angle between the projection of the texture onto the first plane and the first coordinate axis;

[0035] A determining unit is used to obtain the simulated resistivity values ​​of the cylindrical model under different texture conditions and to calculate the relative error of the radial resistivity of the rock under various texture conditions;

[0036] The radial resistivity test error value of the rock is obtained based on the relative error under different texture conditions of the cylindrical model, as well as the length, diameter, and included angle.

[0037] Optionally, the acquisition unit includes:

[0038] The texture development of the blocky rock is obtained through physical analysis, and the blocky rock is layered according to the texture development.

[0039] Determine the resistivity, thickness, and area of ​​each rock layer under different texture conditions;

[0040] The true resistivity values ​​under different texture conditions were obtained using different calculation methods.

[0041] Optionally, the construction unit includes:

[0042] Determine the type of angle relationship between the projection of the texture onto the first plane and the first coordinate axis of the different texture planes of the cylindrical model in the three-dimensional space;

[0043] Based on the type of included angle relationship, different calculation methods are used to obtain the simulated resistivity values ​​of the cylindrical model under different texture conditions.

[0044] Optionally, the determining unit includes:

[0045] The cylindrical model is divided into layers to obtain the resistivity of each layer; wherein the resistivity of each layer corresponds to the resistivity of each layer of the blocky rock.

[0046] The cylindrical model is divided into equal regions, and current is set to flow in from one end and out from the adjacent end.

[0047] A finite element mesh is established, and the potential distribution diagram of the cylindrical model is obtained through the current equation. The cylindrical model is then divided into equal parts.

[0048] The average current value on each section after division is read based on the results of the electric field numerical simulation.

[0049] Obtain simulated resistivity values ​​for cylindrical models under different texture conditions.

[0050] Optionally, the determining unit further includes:

[0051] The cylindrical model is divided into equal regions along the axis in a symmetrical manner.

[0052] The current is set to flow into one end of the equal area block and out the adjacent end; wherein the potential value at the boundary of the inflow end is the maximum value, the potential value on the opposite side is the minimum value, and there is no current value at the adjacent end and the boundary of the adjacent end.

[0053] Optionally, the determining unit further includes:

[0054] Divide the cylindrical model into finite equal parts from top to bottom in any direction.

[0055] Optionally, the determining unit further includes:

[0056] The relative error of the radial resistivity test of the rock is obtained based on the true resistivity value of the blocky rock under different texture conditions and the simulated resistivity value of the corresponding cylindrical model.

[0057] In one aspect, the present invention also includes an electronic device comprising:

[0058] Memory, used to store program instructions;

[0059] A processor is configured to read and execute machine-executable instructions stored in the memory, and to perform the steps included in any optional implementation of the method of the first aspect described above, according to the obtained program instructions.

[0060] One or more technical solutions provided by this invention have at least the following technical effects or advantages:

[0061] The method provided by this invention obtains the true resistivity values ​​of block rocks under different texture conditions and the simulated resistivity values ​​of cylindrical models. Based on these values, the relative error value for the radial resistivity test is calculated. Furthermore, the radial resistivity test error is determined based on the relative error value under different texture conditions. This method addresses the applicability of the method for calculating the radial resistivity of cylindrical rock samples using complex variable functions in characterizing anisotropic rock resistivity. It estimates the accuracy of this radial resistivity test method or performs systematic error analysis. Based on the obtained relative error, it can determine whether the radial resistivity of cylindrical samples obtained using the complex variable function principle is accurate under different rock texture conditions, thus improving the practicality of this method for testing rock resistivity in the oil and gas field. Attached Figure Description

[0062] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0063] Figure 1a , Figure 1b and Figure 1c A schematic diagram illustrating different rock textures provided in an embodiment of the present invention;

[0064] Figure 2 A flowchart illustrating the method for calculating the radial resistivity test error of rocks provided in an embodiment of the present invention;

[0065] Figure 3 This is a schematic diagram of the process for obtaining the true resistivity value of blocky rock according to an embodiment of the present invention;

[0066] Figure 4a and Figure 4b This is a schematic diagram of the first type of rock texture in an embodiment of the present invention.

[0067] Figure 5a and Figure 5b This is a schematic diagram of the second type of rock texture in an embodiment of the present invention.

[0068] Figure 6 This is a schematic diagram of the third type of rock texture in an embodiment of the present invention.

[0069] Figure 7 This is a schematic diagram illustrating the process of calculating simulated resistivity values ​​under different texture conditions, as provided in an embodiment of the present invention.

[0070] Figure 8a and Figure 8b This is the first textured rock cylindrical model in this embodiment of the invention.

[0071] Figure 9a and Figure 9b This is a schematic diagram of a cylindrical rock model with the second texture in an embodiment of the present invention, wherein... Figure 9a This is a 3D model of a cylindrical shape. Figure 9b This is a top view of a cylindrical model.

[0072] Figure 10a and Figure 10b This is a schematic diagram of a cylindrical rock model representing the third texture scenario in this embodiment of the invention. Figure 10a This is a 3D model of a cylindrical shape. Figure 10b This is a top view of a cylindrical model.

[0073] Figure 11 This invention provides an apparatus for measuring the radial resistivity test error of rock cores.

[0074] Figure 12 A computer device for measuring the radial resistivity test error of rock cores is provided in an embodiment of the present invention. Detailed Implementation

[0075] The technical solutions of the embodiments of the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the embodiments of the present invention and the specific features in the embodiments are detailed descriptions of the technical solutions of the embodiments of the present invention, rather than limitations on the technical solutions of the embodiments of the present invention. In the absence of conflict, the embodiments of the present invention and the technical features in the embodiments can be combined with each other.

[0076] Please refer to Figure 1, which is a schematic diagram of different rock textures provided in an embodiment of the present invention. The blocky rock is considered as a cylindrical model, such as... Figure 1a The image shows the first case of rock texture, where the rock texture is parallel to the end face of the cylindrical model, meaning the axial end face of the cylinder is isotropic, or the rock texture is isotropic. Figure 1b The image shows the second case of rock texture, where the rock texture is perpendicular to the end face of the cylinder, and the current flows in along the direction of the texture. Figure 1c As shown, this is the third case of rock texture, in which the rock texture is perpendicular to the end face of the cylinder, and the current flows in perpendicular to the direction of the texture.

[0077] Please see Figure 2 , Figure 2 A schematic flowchart illustrating the method for calculating the radial resistivity test error of rocks provided in an embodiment of the present invention.

[0078] Step S1: Obtain the true resistivity values ​​of blocky rocks under different texture conditions.

[0079] Please see Figure 3 , Figure 3 This is a schematic diagram of the process for obtaining the true resistivity value of blocky rock according to an embodiment of the present invention.

[0080] Step 301: Obtain the texture development of the blocky rock through physical analysis, and then stratify the blocky rock according to the texture development.

[0081] In this embodiment of the invention, CT scans can be used to observe the texture development of blocky rocks, nuclear magnetic resonance images can be used to observe the texture development of blocky rocks, and other physical analysis methods can also be used to observe the texture development. This application does not limit the scope of the invention.

[0082] Step 302: Determine the resistivity, thickness, and area of ​​each rock layer under different texture conditions.

[0083] In this embodiment of the invention, the blocky rock can be divided into n layers according to the development of its texture. Therefore, the resistivity of each layer can be obtained as ρ1, ρ2, ..., ρ n .

[0084] In this embodiment of the invention, specifically, under the first texture condition, the thickness of each rock layer is determined to be h1, h2, ..., h... n In the second texture case, the area corresponding to each layer of rock is determined as S1, S2, ..., S n In the third texture case, the thickness of each rock layer is determined to be h1, h2, ..., h. n .

[0085] Step 303: Use different calculation methods to obtain the true resistivity values ​​under different texture conditions.

[0086] In this embodiment of the invention, different calculation methods are used to calculate the resistivity of rocks under different texture conditions.

[0087] For details, please see Figure 4a and Figure 4b In the first texture case, where the rock texture is parallel to the end face of the cylindrical model, based on the resistivity ρ1, ρ2, ..., ρ of each layer... n And the thickness of each rock layer is h1, h2, ..., h n Since the layered rocks form a parallel circuit in the electrical circuit, according to the principle of parallel circuits, the true resistivity of the rocks in the first case can be obtained. Specifically,

[0088]

[0089] Where, ρ / / h represents the true resistivity value in the first case. i Let ρ be the thickness of the i-th layer of the massive rock. i Let be the resistivity of the i-th layer of the massive rock.

[0090] Please see Figure 5a and Figure 5b In the second case, the rock texture is perpendicular to the end face of the cylinder, and the current flows in along the direction of the texture. Based on the resistivity of each layer (ρ1, ρ2, ..., ρ...),... n And the corresponding areas S1, S2, ..., S of each rock layer nSince the layered rocks form a parallel circuit in the electrical circuit, according to the principle of parallel circuits, the true resistivity of the rocks in the second case can be obtained. Specifically,

[0091]

[0092] Where, ρ h1 For the true resistivity test value in the second case, S i Let ρ be the area of ​​the i-th layer of the massive rock. i Let be the resistivity of the i-th layer of the massive rock.

[0093] Please see Figure 6 In the third case, the rock texture is perpendicular to the end face of the cylinder, and the current flows in perpendicular to the direction of the texture. Based on the resistivity of each layer, ρ1, ρ2, ..., ρ... n And the thickness of each rock layer is h1, h2, ..., h n Therefore, a cuboid can be constructed, with its end face a square with the diameter of the corresponding cylindrical model as its side length. The height of the cuboid is the height of the cylindrical model. The resistivity of each rock layer is designed based on the end face, and the thickness distribution ratio is consistent with the cylindrical end face. In this new cuboid, with the left side input potential at 1V and the right side output potential at 0V, and no potential flow on other faces, according to the current equation...

[0094]

[0095] Where j represents the volume current density, and S represents any closed surface. It represents the decrease in charge per unit time within the volume enclosed by any closed surface;

[0096] The potential distribution map of the cuboid was obtained, a finite element mesh was established, and the cuboid core was divided into 2l+1 equal parts from top to bottom. The average current value I of each section was read from the numerical simulation results of the potential field. c1 I c2 ... I c2l+1 Specifically,

[0097]

[0098] Where, ρ h2 For the true resistivity test value in the third case, I Ci The Cth value read from the numerical simulation results of the electric potential field i The average current value of each cross section.

[0099] Step S2: Construct a cylindrical model corresponding to the blocky rock and establish a three-dimensional spatial coordinate system. Determine the length and diameter of the cylindrical model based on the three-dimensional spatial coordinate system.

[0100] In this embodiment of the invention, a cylindrical core model corresponding to the blocky rock is constructed, and the height and diameter of the cylindrical core model are determined by constructing a three-dimensional spatial coordinate system. Specifically, let the direction along the axial direction of the cylindrical core model be the Z-axis, the direction along the longitudinal centerline of the curved electrode sheet be the X-axis, and the direction perpendicular to the X-axis on the diameter of the end face of the cylindrical core model be the Y-axis. The height L and diameter R of the cylindrical core model are measured according to the three-dimensional spatial coordinate system.

[0101] Step S3: Determine the angle between the texture plane of the cylindrical model and the first plane in three-dimensional space, as well as the angle between the projection of the texture onto the first plane and the first coordinate axis;

[0102] In this embodiment of the invention, in the constructed three-dimensional spatial coordinate system, the plane containing the rock texture is extended to intersect the XOY plane in the three-dimensional spatial coordinate system, with an angle θ between the two planes. The texture is then projected onto the XOY plane to obtain the texture projection OR. At this time, the angle between OR and the X-axis is... The angle between OR and the Y-axis is

[0103] In this embodiment of the invention, there are three types of angles between the texture plane of the rock and the XOY plane, and between the projection of the texture and the X-axis, which correspond to three texture cases of the rock: the angle θ between the texture plane and the XOY plane is 0, and the angle between the projection of the texture on the XOY plane and the X-axis is... This corresponds to the first scenario of rock texture, where the rock texture is parallel to the end face of the cylinder; the angle θ between the plane containing the texture and the XOY plane is π / 2, and the angle between the projection of the texture layer onto the XOY plane and the x-axis is... This corresponds to the second scenario of rock texture, where the rock texture is perpendicular to the end face of the cylinder, and the current flows in along the direction of the texture; the angle θ between the plane containing the texture and the XOY plane is π / 2, and the angle between the projection of the texture onto the XOY plane and the X-axis is... This corresponds to the third case of rock texture, that is, the rock texture is perpendicular to the end face of the cylinder, and the current flows in perpendicular to the direction of the texture.

[0104] In this embodiment of the invention, the calculation method of simulated resistivity value under different texture conditions is determined by different types of included angle relationships, thereby obtaining simulated resistivity value under different texture conditions.

[0105] Step S4: Obtain the simulated resistivity values ​​of the cylindrical model under different texture conditions and calculate the relative error of the radial resistivity of the rock under various texture conditions;

[0106] Please see Figure 7 This is a schematic diagram illustrating the process of calculating simulated resistivity values ​​under different texture conditions provided in an embodiment of the present invention.

[0107] Step 701: Divide the cylindrical model into layers and obtain the resistivity of each layer.

[0108] In this embodiment of the invention, the layering of the cylindrical model corresponds to the layering of the blocky rock, and the resistivity of each layer also corresponds to the resistivity of each layer of the blocky rock, according to ρ1, ρ2, ..., ρ n set up.

[0109] Step 702: Divide the cylindrical model into equal regions, and set the current to flow in from one end and out from the adjacent end.

[0110] In this embodiment of the invention, the cylindrical model is divided into equal regions along a central axis using a symmetrical approach, such as... Figure 8a As shown, the cylindrical model is divided into four equal regions, A, B, C, and D, through its axis. Within this cylindrical model, current is designed to flow in from end A and out from end B. Figure 8b As shown, the potential of boundary A is set to 1V, the potential of boundary C is set to 0V, and there is no current flow on boundaries B and D. This setting creates a potential distribution from high to low in the cylindrical model. Of course, the specific values ​​of the potentials at boundaries A and C are not limited in this embodiment.

[0111] Step 703: Establish a finite element mesh, obtain the potential distribution diagram of the cylindrical model through the current equation, divide the cylindrical model into equal parts, and read the average current value on each section after division according to the electric field numerical simulation results.

[0112] In this embodiment of the invention, the cylindrical model is divided into equal parts by establishing a finite element mesh. Specifically, the cylindrical model is divided into 2m+1 equal parts from top to bottom in any direction. Of course, the specific number of parts into which the cylindrical model is divided by the finite element mesh is not limited in this embodiment.

[0113] In this embodiment of the invention, specifically, according to the current equation

[0114]

[0115] Where j represents the volume current density, and S represents any closed surface. It represents the decrease in charge per unit time within the volume enclosed by any closed surface;

[0116] The potential distribution diagram in the cylindrical model is obtained.

[0117] In this embodiment, based on the obtained potential distribution diagram and the various cross sections obtained after finite element mesh generation, the average current values ​​I1, I2, ..., I of each cross section are read from the numerical simulation results of the potential field. 2m+1 .

[0118] Step 704: Obtain the simulated resistivity values ​​of different cylindrical models under different texture conditions.

[0119] In this embodiment of the invention, after obtaining the average current value of each cross section, the simulated resistivity value of the cylindrical model is calculated under different texture conditions.

[0120] Specifically, such as Figure 8a and Figure 8b The image shown is a schematic diagram of a cylindrical model under the first texture condition according to an embodiment of the present invention.

[0121]

[0122] Obtain the simulated resistivity value under this condition.

[0123] Where, ρ / / * represents the resistivity value obtained from numerical simulation in the first case, I i Let be the average current value of the i-th cross section;

[0124] In embodiments of the present invention, such as Figure 9a and Figure 10a The figures shown are schematic diagrams of the cylindrical models under the second and third texture conditions according to embodiments of the present invention. Since the calculation method for the simulated resistivity value is the same as that under the first texture condition in the second and third texture conditions, it will not be described again here.

[0125] In this embodiment of the invention, after obtaining the true resistivity values ​​of blocky rocks under various texture conditions and the simulated resistivity values ​​of the corresponding cylindrical models, the relative error calculation formula is used.

[0126]

[0127] Where ε is the test error value of the radial resistivity of the rock in each case, and ρ * ρ represents the simulated resistivity value for each case, and ρ represents the true resistivity value for each case.

[0128] In this embodiment of the invention, specifically taking the third texture case as an example, observation through CT scans or nuclear magnetic resonance images reveals that, based on the development of the laminae, the core sample can be divided into layer 1 and layer 2 along the green bedding. The rock resistivity of each layer corresponds to ρ1 = 1 Ω·m and ρ2 = 10 Ω·m, respectively, and the thickness of each layer corresponds to H1 = 0.2 m and H2 = 0.8 m. Correspondingly, a cuboid can be constructed, with its end face a square with the diameter of the corresponding cylindrical model as its side length. The height of the cuboid is used as the height of the cylindrical model. The rock resistivity of each layer is designed in accordance with the end face, and the thickness distribution ratio is consistent with that of the cylindrical end face.

[0129] For the newly designed cuboid, with an input potential of 1V on the left and an output potential of 0V on the right, and no potential flow on other faces, a finite element mesh is established. Based on the current equation, the potential distribution diagram of the cuboid can be obtained. The cuboid core is divided into 5 equal parts from top to bottom, and the average current value I of each section is read from the numerical simulation results of the potential field. c1 =I c2 =……=I c5 =0.122A. The resistivity value passing through the left and right sides of the cuboid can be calculated using the formula.

[0130] Next, the resistivity of the cylindrical model corresponding to the third texture case is calculated. The resistivity of each layer of the constructed cylindrical model is set as ρ1 = 1 Ω·m and ρ2 = 10 Ω·m, respectively. Current flows in from end A and out from end B. The potential of boundary A is set to 1V, the potential of boundary C is set to 0V, and there is no current flow at boundaries B and D. A finite element mesh is established, and the potential distribution diagram for the third case can be obtained according to the current equation. The cylindrical core is divided into 5 equal parts from top to bottom, and the average current value of each section is read from the numerical simulation results of the potential field: I1 = I2 = ... = I5 = 0.102A. The resistivity value of the numerical simulation can be calculated according to the formula.

[0131] The relative error of the radial resistivity test of the rock under the third texture condition is:

[0132]

[0133] Step S5: Obtain the radial resistivity test error value of the rock based on the relative error under different texture conditions of the cylindrical model, as well as the length, diameter, and included angle.

[0134] In this embodiment of the invention, after obtaining the relative error values ​​under different texture conditions, as well as the height and diameter of the cylindrical model, the angle between the texture plane and the XOY plane, and the angle between the texture projection on the XOY plane and the X-axis, the formula is used...

[0135]

[0136] Calculate the error value of the radial resistivity test of the rock.

[0137] Specifically, ε is the error value of the rock radial resistivity test, R is the diameter of the cylindrical model, and θ is the angle between the texture plane and the XOY plane. Let L be the angle between the projection of the texture onto the XOY plane and the X-axis, and let L be the height of the cylindrical model. / / ε represents the relative error value of the rock radial resistivity test in the first case. h1 ε represents the relative error value of the rock radial resistivity test in the second case. h2 This represents the relative error value for the radial resistivity test of the rock in the third case.

[0138] The method provided by this invention obtains the true resistivity values ​​of block rocks under different texture conditions and the simulated resistivity values ​​of cylindrical models. Based on these values, the relative error value for the radial resistivity test is calculated. Furthermore, the radial resistivity test error is determined based on the relative error value under different texture conditions. This method addresses the applicability of the method for calculating the radial resistivity of cylindrical rock samples using complex variable functions in characterizing anisotropic rock resistivity. It estimates the accuracy of this radial resistivity test method or performs systematic error analysis. Based on the obtained relative error, it can determine whether the radial resistivity of cylindrical samples obtained using the complex variable function principle is accurate under different rock texture conditions, thus improving the practicality of this method for testing rock resistivity in the oil and gas field.

[0139] Secondly, embodiments of the present invention also provide a device for measuring the radial resistivity test error of rock cores, such as... Figure 11 The image shows an apparatus for measuring the radial resistivity test error of a rock core according to an embodiment of the present invention. The apparatus 1100 includes: an acquisition unit 1101, a construction unit 1102, and a determination unit 1103.

[0140] The acquisition unit 1101 is used to acquire the true resistivity values ​​of the blocky rock under different texture conditions; the construction unit 1102 is used to construct a cylindrical model corresponding to the blocky rock and construct a three-dimensional spatial coordinate system, and determine the length and diameter of the cylindrical model according to the three-dimensional spatial coordinate system; and to determine the angle between the texture plane of the cylindrical model and the first plane in the three-dimensional space and the projection of the texture onto the first plane and the first coordinate axis; the determination unit 1103 is used to obtain the simulated resistivity values ​​of the cylindrical model under different texture conditions and calculate the relative error of the rock radial resistivity under various texture conditions; and to obtain the test error value of the rock radial resistivity according to the relative error of the cylindrical model under different texture conditions, as well as the length, diameter and the angle.

[0141] Specifically, the acquisition unit 1101 is used for:

[0142] The texture development of the blocky rock is obtained through physical analysis, and the blocky rock is layered according to the texture development.

[0143] Determine the resistivity, thickness, and area of ​​each rock layer under different texture conditions;

[0144] The true resistivity values ​​under different texture conditions were obtained using different calculation methods.

[0145] Specifically, the construction unit 1102 is used for:

[0146] Determine the type of angle relationship between the projection of the texture onto the first plane and the first coordinate axis of the different texture planes of the cylindrical model in the three-dimensional space;

[0147] Based on the type of included angle relationship, different calculation methods are used to obtain the simulated resistivity values ​​of the cylindrical model under different texture conditions.

[0148] Specifically, the determining unit 1103 is used for:

[0149] The cylindrical model is divided into layers to obtain the resistivity of each layer; wherein the resistivity of each layer corresponds to the resistivity of each layer of the blocky rock.

[0150] The cylindrical model is divided into equal regions, and current is set to flow in from one end and out from the adjacent end.

[0151] A finite element mesh is established, and the potential distribution diagram of the cylindrical model is obtained through the current equation. The cylindrical model is then divided into equal parts.

[0152] The average current value on each section after division is read based on the results of the electric field numerical simulation.

[0153] Obtain simulated resistivity values ​​for cylindrical models under different texture conditions.

[0154] Specifically, the determining unit 1103 is also used for:

[0155] The cylindrical model is divided into equal regions along the axis in a symmetrical manner.

[0156] The current is set to flow into one end of the equal area block and out the adjacent end; wherein the potential value at the boundary of the inflow end is the maximum value, the potential value on the opposite side is the minimum value, and there is no current value at the adjacent end and the boundary of the adjacent end.

[0157] Specifically, the determining unit 1103 is also used for:

[0158] Divide the cylindrical model into finite equal parts from top to bottom in any direction.

[0159] Specifically, the determining unit 1103 is also used for:

[0160] The relative error of the radial resistivity test of the rock is obtained based on the true resistivity value of the blocky rock under different texture conditions and the simulated resistivity value of the corresponding cylindrical model.

[0161] Finally, embodiments of the present invention also provide an electronic device, such as... Figure 12 The diagram shown is a schematic representation of a computer device provided in an embodiment of the present invention. The device 1200 includes a memory 1201 and a processor 1202.

[0162] Specifically, memory 1201 is used to store program instructions;

[0163] The processor 1202 is configured to call program instructions stored in memory and execute the steps included in any optional implementation of the method of the first aspect described above, according to the obtained program instructions.

[0164] The numerical simulation method for testing the radial resistivity of rocks provided in this invention obtains the true resistivity of block rocks under different texture conditions and the simulated resistivity value of a cylindrical model. Based on the obtained true resistivity values ​​of block rocks under different texture conditions and the simulated resistivity values ​​of the cylindrical model, the relative error value of the radial resistivity test is calculated. Furthermore, based on the relative error value under different texture conditions, the radial resistivity test error of the rock is obtained. This method addresses the applicability of the calculation method for the radial resistivity of cylindrical rock samples using complex variable functions in characterizing anisotropic rock resistivity. It estimates the accuracy of this radial resistivity testing method or performs systematic error analysis on the method. Therefore, based on the obtained relative error, it can determine whether the radial resistivity of the cylindrical sample obtained using the complex variable function principle is accurate under different rock texture conditions, thus improving the practicality of this method for testing rock resistivity in the oil and gas field.

[0165] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of the invention.

[0166] Obviously, those skilled in the art can make various modifications and variations to the embodiments of the present invention without departing from the spirit and scope of the embodiments of the present invention. Thus, if these modifications and variations to the embodiments of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention also intends to include these modifications and variations.

Claims

1. A method for calculating the error in a rock radial resistivity test, characterized in that, include: Obtain the true resistivity values ​​of blocky rocks under different texture conditions; Construct a cylindrical model corresponding to the blocky rock and a three-dimensional spatial coordinate system, and determine the length and diameter of the cylindrical model based on the three-dimensional spatial coordinate system; Determine the angle between the texture plane of the cylindrical model and the first plane in the three-dimensional space, and the angle between the projection of the texture onto the first plane and the first coordinate axis; The simulated resistivity values ​​of the cylindrical model under different texture conditions were obtained, and the relative error of the radial resistivity of the rock under various texture conditions was calculated. The radial resistivity test error value of the rock is obtained based on the relative error under different texture conditions of the cylindrical model, as well as the length, diameter, and included angle. Obtaining the simulated resistivity values ​​of the cylindrical model under different texture conditions includes: Determine the type of angle relationship between the projection of the texture onto the first plane and the first coordinate axis of the different texture planes of the cylindrical model in the three-dimensional space; Based on the type of included angle relationship, different calculation methods are used to obtain the simulated resistivity values ​​of the cylindrical model under different texture conditions; The simulated resistivity values ​​of the cylindrical model under different texture conditions were obtained using different calculation methods, including: The cylindrical model is divided into layers to obtain the resistivity of each layer; wherein the resistivity of each layer corresponds to the resistivity of each layer of the blocky rock. The cylindrical model is divided into equal regions, and current is set to flow in from one end and out from the adjacent end. A finite element mesh is established, and the potential distribution diagram of the cylindrical model is obtained through the current equation. The cylindrical model is then divided into equal parts. The average current value on each section after division is read based on the results of the electric field numerical simulation. Obtain simulated resistivity values ​​for cylindrical models under different texture conditions.

2. The method as described in claim 1, characterized in that, Obtain the true resistivity values ​​of blocky rocks under different texture conditions, including: The texture development of the blocky rock is obtained through physical analysis, and the blocky rock is layered according to the texture development. Determine the resistivity, thickness, and area of ​​each rock layer under different texture conditions; The true resistivity values ​​under different texture conditions were obtained using different calculation methods.

3. The method as described in claim 1, characterized in that, The cylindrical model is divided into equal regions, with current flowing in from one end and out from the adjacent end, including: The cylindrical model is divided into equal regions along the axis in a symmetrical manner. The current is configured to flow into one end of the equal-region block and out at the adjacent end; wherein, the inflow end... The potential value at the boundary is the maximum value, the potential value on the opposite side is the minimum value, and there is no current value at the adjacent ends and the boundary of the adjacent ends.

4. The method as described in claim 1, characterized in that, A finite element mesh is created, dividing the cylindrical model into equal parts, including: Divide the cylindrical model into finite equal parts from top to bottom in any direction.

5. The method as described in claim 1, characterized in that, Calculate the relative error of rock radial resistivity under various texture conditions, including: The relative error of the radial resistivity test of the rock is obtained based on the true resistivity value of the blocky rock under different texture conditions and the simulated resistivity value of the corresponding cylindrical model.

6. A device for measuring the radial resistivity error of rocks, characterized in that, include: The acquisition unit is used to acquire the true resistivity values ​​of blocky rocks under different texture conditions; A construction unit is used to construct a cylindrical model corresponding to the blocky rock and to construct a three-dimensional spatial coordinate system. The length and diameter of the cylindrical model are determined according to the three-dimensional spatial coordinate system. And the angle between the texture plane of the cylindrical model and the first plane in the three-dimensional space, and the angle between the projection of the texture onto the first plane and the first coordinate axis; A determining unit is used to obtain the simulated resistivity values ​​of the cylindrical model under different texture conditions and to calculate the relative error of the radial resistivity of the rock under various texture conditions; And the radial resistivity test error value of the rock is obtained based on the relative error under different texture conditions of the cylindrical model, as well as the length, diameter and the included angle; Construction units, including: Determine the type of angle relationship between the projection of the texture onto the first plane and the first coordinate axis of the different texture planes of the cylindrical model in the three-dimensional space; Based on the type of included angle relationship, different calculation methods are used to obtain the simulated resistivity values ​​of the cylindrical model under different texture conditions; The defined unit includes: The cylindrical model is divided into layers to obtain the resistivity of each layer; wherein the resistivity of each layer corresponds to the resistivity of each layer of the blocky rock. The cylindrical model is divided into equal regions, and current is set to flow in from one end and out from the adjacent end. A finite element mesh is established, and the potential distribution diagram of the cylindrical model is obtained through the current equation. The cylindrical model is then divided into equal parts. The average current value on each section after division is read based on the results of the electric field numerical simulation. Obtain simulated resistivity values ​​for cylindrical models under different texture conditions.

7. The apparatus as claimed in claim 6, characterized in that, The acquisition unit includes: The texture development of the blocky rock is obtained through physical analysis, and the blocky rock is layered according to the texture development. Determine the resistivity, thickness, and area of ​​each rock layer under different texture conditions; The true resistivity values ​​under different texture conditions were obtained using different calculation methods.

8. The apparatus as claimed in claim 6, characterized in that, The determining unit, Also includes; The cylindrical model is divided into equal regions along the axis in a symmetrical manner. The current is configured to flow into one end of the equal-region block and out at the adjacent end; wherein, the inflow end... The potential value at the boundary is the maximum value, the potential value on the opposite side is the minimum value, and there is no current value at the adjacent ends and the boundary of the adjacent ends.

9. The apparatus as claimed in claim 6, characterized in that, The determining unit, Also includes: Divide the cylindrical model into finite equal parts from top to bottom in any direction.

10. The apparatus as claimed in claim 6, characterized in that, The determining unit also include: The relative error of the radial resistivity test of the rock is obtained based on the true resistivity value of the blocky rock under different texture conditions and the simulated resistivity value of the corresponding cylindrical model.

11. An electronic device comprising a processor and a memory; characterized in that, The memory is used to store machine-executable instructions; The processor is configured to read and execute machine-executable instructions stored in the memory to implement the method as described in any one of claims 1 to 5.

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