Method and device for determining electrical parameters of a trihydrous model rock, equipment and storage medium

Abstract

This application discloses a method, apparatus, equipment, and storage medium for determining the rock electrical parameters of a "three-water" model. The method includes determining the rock electrical parameters in the "three-water" model based on multi-resolution digital core technology. Using pore radius as the standard, free pore, micropore, and clay pore components are extracted from digital cores of different resolutions to construct digital cores containing free pores, micropores, and wet clay, respectively. Furthermore, considering the conductivity mechanism of each component separately, numerical simulations are used to construct cross-plots of formation factors and porosity for digital cores containing different pore sizes. The rock electrical parameters of the three components in the "three-water" model are obtained through fitting. This application achieves accurate determination of key parameters of the "three-water" model and calculation of reservoir saturation.

Description

Technical Field

[0001] The embodiments of the present invention relate to the technical field of oil and gas exploration, and in particular to a method, apparatus, equipment and storage medium for determining the rock electrical parameters of a three-water model. Background Technology

[0002] The "three-water" model is a widely used model in geology and geophysics, primarily used to explain the electrical conductivity of rocks. The rock conductivity pathway consists of three parallel components: free water, micropore water, and clay water. Free water refers to water that can flow freely and be produced under formation pressure; micropore water refers to water that resides in the tiny pores of the rock and is typically unable to flow or be produced under formation pressure; and clay water is water with special conductivity formed near clay due to cation exchange and salt expulsion. This model incorporates a lithology coefficient to further refine the "three-water" model, resulting in the following expression:

[0003]

[0004] In the formula, R t For the rock resistivity, φ f It is the free water porosity, a decimal; φ i It is the porosity of microporous water, a decimal; φ c It is the water porosity of clay, a decimal; m f It is the cementation index of rocks containing free water, dimensionless; m i It is the cementation index of microporous rocks, dimensionless; m c It is the cementation index corresponding to clay-water rock (wet clay), dimensionless; n f It is the saturation index, dimensionless; S wf It represents the water saturation in the pores of a free fluid, a decimal. f and b f a i a c R represents the lithology-related coefficients for rocks containing free water, rocks with microporous water, and clay, respectively, and are dimensionless. w and R wc Ω·m represents the resistivity of groundwater and clay water, respectively.

[0005] The "three-water" model is simple to understand and has a clear mechanism, making it widely used in tight oil and gas reservoirs. However, the model has numerous parameters that are difficult to obtain, especially the rock electrical parameters (m) for different components. f m i m c n f a f b f a i a wDetermining these parameters is quite difficult. Currently, the effective porosity method is commonly used. This method classifies rocks based on the lower limit of reservoir effective porosity. Rocks with porosity greater than the lower limit are considered free-porosity rocks, while those with porosity less than the lower limit are considered microporous rocks. The lithology coefficient and cementation index are fitted using rock electrical experimental results, while empirical values ​​(a=1, m=2) are used for the rock electrical parameters of clay-water porous rocks (wet clay).

[0006] The effective porosity lower limit method can conveniently determine the rock electrical parameters of each component, but it has two problems:

[0007] (1) The rationality of using the lower limit of effective porosity to distinguish between free water pores and micropores is questionable. Samples with porosity greater than the lower limit of effective porosity may contain micropores and clay pores, while samples with porosity less than the lower limit of effective porosity may also contain free pores. Therefore, it is not rigorous to consider core samples with porosity greater than the lower limit of effective porosity as free pores and samples with porosity less than the lower limit of effective porosity as micropores.

[0008] (2) It is inaccurate to take empirical values ​​or approximate them with micropore water components as the rock electrical parameters of clay water components (wet clay). Many scholars have confirmed that the conductivity of clay water is different from that of formation water, while the conductivity mechanism of micropore water and free water is the same. Therefore, it is unreasonable to take empirical values ​​or approximate them with micropore components as the rock electrical parameters of clay water pores.

[0009] The two problems mentioned above lead to inaccurate rock electrical parameters of each component, resulting in poor accuracy in evaluating oil and gas reservoir saturation using the "three-water" model, thus limiting the application of the model. Summary of the Invention

[0010] The purpose of this invention is to provide at least one method, apparatus, device, and storage medium for determining rock electrical parameters in a three-water model, which can at least address the existing technical problem of difficulty in determining rock electrical parameters in a three-water model.

[0011] To address the aforementioned technical problems, at least one embodiment of this application provides a method for determining the rock electrical parameters of a three-water model, comprising:

[0012] First-resolution digital cores and second-resolution digital cores of rock samples, as well as digital cores of clay components of pure clay samples, are obtained, wherein the first resolution is higher than the second resolution.

[0013] Connectivity analysis was performed on the first resolution digital core and the second resolution digital core. Based on the pore radius boundaries of free pores, micropores and clay pores, the free pores and micropores of the first resolution digital core and the second resolution digital core were extracted to construct digital cores containing free pores and digital cores containing micropores. Clay pores of the clay component digital core were extracted to construct wet clay digital cores.

[0014] Numerical simulations were performed on the digital core containing free pores, the digital core containing micropores, and the digital core containing wet clay, respectively, to obtain the first stratigraphic factor of the digital rock containing free pores, the second stratigraphic factor of the digital rock containing micropores, and the third stratigraphic factor of the digital rock containing clay pores.

[0015] The first porosity of free pores, the second porosity of micropores, and the third porosity of clay pores are determined. Based on the first cross-plot of the first stratigraphic factor and the first porosity, the first rock electrical parameter corresponding to free pores is determined. Based on the second cross-plot of the second stratigraphic factor and the second porosity, the second rock electrical parameter corresponding to micropores is determined. Based on the cross-plot of the third stratigraphic factor and the third porosity, the third rock electrical parameter corresponding to clay pores is determined.

[0016] At least one embodiment of this application also provides a device for determining the rock electrical parameters of a three-water model, comprising:

[0017] The acquisition module is used to acquire first-resolution digital cores and second-resolution digital cores of rock samples, as well as clay component digital cores of pure clay samples, wherein the first resolution is higher than the second resolution.

[0018] The module is used to perform connectivity analysis on the first resolution digital core and the second resolution digital core, and extract the free pores and micropores of the first resolution digital core and the second resolution digital core according to the pore radius boundaries of free pores, micropores and clay pores, to construct digital cores containing free pores and digital cores containing micropores, and to extract the clay pores of the clay component digital core to construct wet clay digital cores;

[0019] The numerical simulation module is used to perform numerical simulations on the digital core containing free pores, the digital core containing micropores, and the digital core containing wet clay, respectively, to obtain the first stratigraphic factor of the digital rock containing free pores, the second stratigraphic factor of the digital rock containing micropores, and the third stratigraphic factor of the digital rock containing clay pores.

[0020] The rock electrical parameter determination module is used to determine the first porosity of free pores, the second porosity of micropores, and the third porosity of clay pores. Based on the first cross-plot of the first stratigraphic factor and the first porosity, it determines the first rock electrical parameter corresponding to free pores, based on the second cross-plot of the second stratigraphic factor and the second porosity, it determines the second rock electrical parameter corresponding to micropores, and based on the cross-plot of the third stratigraphic factor and the third porosity, it determines the third rock electrical parameter corresponding to clay pores.

[0021] At least one embodiment of this application also provides an electronic device, including: at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, the instructions being executed by the at least one processor to enable the at least one processor to perform the above-described method for determining the rock electrical parameters of the three-water model.

[0022] At least one embodiment of this application also provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the above-described method for determining the rock electrical parameters of a three-water model.

[0023] The method for determining rock electrical parameters in a three-water model provided in this application is the first to propose a method based on multi-resolution digital core technology to determine the rock electrical parameters in a three-water model. Using pore radius as the standard, free pores, micropores, and clay pore components are extracted from digital cores of different resolutions to construct digital cores containing free pores, micropores, and wet clay, respectively. Then, considering the conductivity mechanism of each part separately, numerical simulations are used to construct F-φ cross plots and RI-S plots for digital cores containing different pore sizes. w The cross-plot was used to obtain the rock electrical parameters of the three parts of the "three-water" model through fitting. This embodiment achieves accurate determination of key parameters of the "three-water" model and calculation of reservoir saturation, and can be extended to any type of reservoir.

[0024] In some optional embodiments, it also includes:

[0025] The distribution of oil and water in the pores of the free-pore digital core was simulated to determine the rock resistivity index under different water saturation levels.

[0026] A cross-plot of resistivity index and water saturation was established, and the fourth rock electrical parameter of free pores was determined by fitting.

[0027] Based on the three-water model, the water saturation model in free pores is determined according to the first, second, third, and fourth rock electrical parameters.

[0028] Since oil and gas exist only in free pore space, by determining the rock resistivity of free pores at different saturation levels, the fourth rock electrical parameter can be determined. Furthermore, by combining the first, second, and third rock electrical parameters, the water saturation model in free pores can be determined.

[0029] In some optional embodiments, it also includes:

[0030] The formation total water saturation model is determined based on the water saturation model in the free pores.

[0031] The water saturation of the reservoir is evaluated based on the total water saturation model of the formation.

[0032] In this way, the water saturation of the reservoir can be evaluated using the total water saturation model of the formation, and the calculation process is simple.

[0033] In some alternative embodiments, the first resolution is 0.03 μm; the second resolution is 2 μm.

[0034] Digital core samples with different resolutions can accurately identify free pores, micropores, and clay pores, and the operation is simple and convenient.

[0035] In some optional embodiments, the steps of performing connectivity analysis on the first resolution digital core and the second resolution digital core, extracting the free pores and micropores of the first resolution digital core and the second resolution digital core based on the pore radius boundaries of free pores, micropores and clay pores, constructing digital cores containing free pores and digital cores containing micropores, and extracting clay pores from the clay component digital core to construct a wet clay digital core further include:

[0036] The definition of free pores includes all pores in the second resolution digital core and connected pores with a pore radius greater than 0.6 μm in the first resolution digital core;

[0037] The micropores are defined as isolated pores in the first resolution digital core and interconnected pores with pore radii between 0.1 μm and 0.6 μm.

[0038] In addition, it is determined that the clay pores include the pores in the digital core of the clay component.

[0039] Using multi-resolution digital cores with a first resolution of 0.03 μm and a second resolution of 2 μm, pores with a pore radius greater than 0.6 μm were identified as free water pores, pores with a pore radius between 0.1 μm and 0.6 μm and isolated pores were identified as micropores, and pores extracted from pure clay were identified as clay pores. This method enables accurate identification of each pore type, which facilitates subsequent extraction.

[0040] In some optional embodiments, the steps of performing connectivity analysis on the first resolution digital core and the second resolution digital core, extracting the free pores and micropores of the first resolution digital core and the second resolution digital core based on the pore radius boundaries of free pores, micropores and clay pores, constructing digital cores containing free pores and digital cores containing micropores, and extracting clay pores from the clay component digital core to construct a wet clay digital core further include:

[0041] The cutoff values ​​for free pores and micropores, as well as the cutoff values ​​for micropores and clay pores, were determined using nuclear magnetic resonance experiments.

[0042] The pore radius limits of free pores, micropores, and clay pores are determined based on the cutoff values ​​of the free pores and micropores, as well as the cutoff values ​​of micropores and clay pores.

[0043] The pore radius can be determined simply and conveniently by setting the cutoff values ​​for free pores and micropores, as well as the cutoff values ​​for micropores and clay pores.

[0044] In some optional embodiments, the step of performing numerical simulations on the digital cores containing free pores, microporous digital cores, and wet clay digital cores respectively to obtain the first stratigraphic factor of the free pore digital rock, the second stratigraphic factor of the microporous digital rock, and the third stratigraphic factor of the clay-porosity digital rock includes:

[0045] The digital cores containing free pores, micropores, and wet clay were respectively fully saturated with water.

[0046] The resistivity of the digital core containing free pores, the digital core containing micropores, and the digital core containing wet clay when fully saturated with water was simulated using the finite element method.

[0047] The first stratigraphic factor of the free-pore digital rock, the second stratigraphic factor of the microporous digital rock, and the third stratigraphic factor of the clay-porous digital rock were determined based on the resistivity of the digital core containing free pores, the digital core containing microporous rocks, and the digital core containing wet clay when fully saturated with water.

[0048] The resistivity of digital cores with free pores, digital cores with micropores, and digital cores of wet clay under fully saturated conditions is used to determine stratigraphic factors. Attached Figure Description

[0049] One or more embodiments are illustrated by way of example with reference to the accompanying drawings, and these illustrative descriptions do not constitute a limitation on the embodiments.

[0050] Figure 1This is a flowchart of a method for determining rock electrical parameters of a three-water model provided in one embodiment of this application;

[0051] Figure 2 This is a flowchart of a method for determining rock electrical parameters of a three-water model provided in another embodiment of this application;

[0052] Figure 3 This is a flowchart illustrating the overall concept of a method for determining rock electrical parameters in a three-water model, provided in another embodiment of this application.

[0053] Figure 4 This is a schematic diagram of the construction of multi-resolution digital cores in step A of another embodiment of this application;

[0054] Figure 5 This is a schematic diagram of the extraction of digital core pores in step C provided in another embodiment of this application;

[0055] Figure 6 This is the F-φ intersection diagram constructed in step D of another embodiment of this application;

[0056] Figure 7 The RI-S constructed in step E is provided in another embodiment of this application. w Intersection diagram;

[0057] Figure 8 This is a logging evaluation result of reservoir saturation in well L in a basin provided in one embodiment of this application;

[0058] Figure 9 This is a schematic diagram of a device for determining the rock electrical parameters of a three-water model provided in another embodiment of this application;

[0059] Figure 10 This is a schematic diagram of the structure of an electronic device provided in another embodiment of this application.

[0060] In the accompanying drawings, the same parts are referred to by the same reference numerals, and the drawings are not drawn to scale. Detailed Implementation

[0061] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the various embodiments of this application will be described in detail below with reference to the accompanying drawings. However, those skilled in the art will understand that many technical details are presented in the various embodiments of this application to facilitate a better understanding of the application. However, the technical solutions claimed in this application can be implemented even without these technical details and various variations and modifications based on the following embodiments. The division of the various embodiments below is for ease of description and should not constitute any limitation on the specific implementation of this application. The various embodiments can be combined with and referenced by each other without contradiction.

[0062] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this disclosure are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this disclosure described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0063] It should be noted that the steps shown in the flowchart in the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions, and although a logical order is shown in the flowchart, in some cases the steps shown or described may be executed in a different order than that shown here.

[0064] This invention proposes a method for determining the rock electrical parameters of a three-water model. The implementation details of the method for determining the rock electrical parameters of a three-water model in this embodiment are described below. The following content is only for the convenience of understanding and is not necessary for implementing this solution.

[0065] Example 1:

[0066] The specific process of determining the rock electrical parameters of the three-water model in this embodiment can be described as follows: Figure 1 As shown, it includes:

[0067] Step 110: Obtain a first-resolution digital core, a second-resolution digital core, and a clay component digital core of a pure clay sample, wherein the first resolution is higher than the second resolution.

[0068] Digital cores are reconstructed based on two-dimensional scanning electron microscope images or three-dimensional CT scan images using computer image processing technology and certain algorithms.

[0069] In some examples, representative core samples from reservoir locations are selected for micron-level CT scans at different resolutions to construct low-resolution and high-resolution 3D digital cores. This allows for the acquisition of both first-resolution and second-resolution digital cores of the rock samples. In this embodiment, acquiring digital cores at different resolutions facilitates the extraction of pores of different sizes, enabling accurate pore identification.

[0070] In some cases, nano-CT scans were performed on pure clay sites to construct 3D digital cores of clay components.

[0071] Step 120: Conduct connectivity analysis on the first resolution digital core and the second resolution digital core, and extract the free pores and micropores of the first resolution digital core and the second resolution digital core according to the pore radius boundaries of free pores, micropores and clay pores to construct digital cores containing free pores and digital cores containing micropores, and extract the clay pores of the clay component digital core to construct wet clay digital cores.

[0072] Specifically, connectivity analysis was performed on the first-resolution digital core and the second-resolution digital core, and connected pores were extracted based on the pore radius boundaries of free pores, micropores and clay pores, respectively, to construct digital cores containing free pores, micropores and wet clay.

[0073] Free pores generally refer to the spaces within a rock that are not completely occupied by solid matter, allowing fluids (such as water, oil, and gas) to flow freely. Free pores typically have a large radius, capable of accommodating larger fluid molecules. Micropores refer to pores with smaller diameters, which function in rocks to store water and contain adsorbed and capillary water. Clay pores specifically refer to the tiny gaps between clay mineral particles; the size and shape of these gaps are influenced by the type of clay mineral, its arrangement, and the degree of compaction.

[0074] Step 130: Numerical simulations are performed on the digital core containing free pores, the digital core containing micropores, and the digital core containing wet clay, respectively, to obtain the first stratigraphic factor of the digital rock containing free pores, the second stratigraphic factor of the digital rock containing micropores, and the third stratigraphic factor of the digital rock containing clay pores.

[0075] Specifically, the conductivity of each part of the digital core containing free pores, the digital core containing micropores, and the digital core containing wet clay are considered separately, and numerical simulations are carried out for the digital core containing free pores, the digital core containing micropores, and the digital core containing wet clay; the stratigraphic factors of saturated rocks are calculated.

[0076] Among them, the formation factor is used to describe the relationship between the electrical conductivity of rocks and the electrical conductivity of pore fluids. Specifically, the formation factor refers to the ratio of the resistivity of a rock to its resistivity when it is completely water-bearing (i.e., 100% of the porosity is occupied by water).

[0077] Step 140: Determine the first porosity of free pores, the second porosity of micropores, and the third porosity of clay pores; determine the first rock electrical parameter corresponding to free pores based on the first cross-plot of the first stratigraphic factor and the first porosity; determine the second rock electrical parameter corresponding to micropores based on the second cross-plot of the second stratigraphic factor and the second porosity; and determine the third rock electrical parameter corresponding to clay pores based on the cross-plot of the third stratigraphic factor and the third porosity.

[0078] Specifically, based on stratigraphic factors and porosity, stratigraphic factor-porosity cross plots (i.e., F-φ cross plots) were constructed for free-porosity digital rocks, microporous digital rocks, and wet clay digital rocks, respectively, and the rock electrical parameter a was fitted to each of the three components. f and m f a i and m i a c and m c Specifically, based on a first cross-plot of the first stratigraphic factor and the first porosity, the first rock electrical parameter corresponding to the free pores is determined; based on a second cross-plot of the second stratigraphic factor and the second porosity, the second rock electrical parameter corresponding to the micropores is determined; and based on a cross-plot of the third stratigraphic factor and the third porosity, the third rock electrical parameter corresponding to the clay pores is determined; where F is the stratigraphic factor, F... f F i and F c These refer to the stratigraphic factors of free-porosity digital rocks, microporous digital rocks, and wet clay digital rocks, respectively; similarly, φ represents porosity. f It is the porosity of free water; φ i It refers to the porosity of microporous water; φ c It refers to the water porosity of clay; and a and m are used to refer to rock electrical parameters, a f and m f Rock electrical parameters used to refer to free pores; a i and m i Rock electrical parameters used to refer to micropores; a c and m c Rock electrical parameters used to refer to the pore size of clay.

[0079] In this embodiment, a novel approach is proposed to determine the rock electrical parameters in a "three-water" model based on multi-resolution digital core technology. Using pore radius as the standard, free pore, micropore, and clay pore components are extracted from digital cores of different resolutions, constructing digital cores containing free pores, micropores, and wet clay, respectively. Then, considering the conductivity mechanism of each component separately, numerical simulations are used to construct F-φ cross plots and RI-S plots for digital cores containing different pore sizes. w The cross-plot was used to obtain the rock electrical parameters of the three parts of the "three-water" model through fitting. This embodiment achieves accurate determination of key parameters of the "three-water" model and calculation of reservoir saturation, and can be extended to any type of reservoir.

[0080] In some embodiments, the first resolution is 0.03 μm; the second resolution is 2 μm.

[0081] Specifically, representative core samples from reservoir locations were selected for micron-scale CT scanning at different resolutions, namely 2 μm and 0.03 μm; pure clay samples were selected for nano-scale CT scanning at a resolution of 10 nm. Digital core samples were constructed for each of these samples, with a size of 600×600×600 voxels. Furthermore, the number of samples for each resolution CT scan was 5.

[0082] Of course, in other embodiments, the applicability of the first and second resolutions can be adjusted according to the reservoir conditions in different regions to ensure that porosity can be identified as much as possible based on the formation characteristics. This document does not limit the specific values ​​of the first and second resolutions.

[0083] In some embodiments, the step of determining the pore radius limits of free pores, micropores, and clay pores includes:

[0084] The cutoff values ​​for free pores and micropores, as well as the cutoff values ​​for micropores and clay pores, were determined using nuclear magnetic resonance experiments.

[0085] The pore radius limits of free pores, micropores, and clay pores are determined based on the cutoff values ​​of the free pores and micropores, as well as the cutoff values ​​of micropores and clay pores.

[0086] Specifically, rocks contain free pores, micropores, and clay pores simultaneously. Nuclear magnetic resonance (NMR) experiments can determine the T2 cutoff values ​​for free pores and micropores. Previous experiments have shown that the T2 cutoff value for micropores and clay pores is 3 ms. Taking dense sandstone as an example, NMR experiments have determined the T2 cutoff value for free pores and micropores to be 20 ms.

[0087] Using the T2 cutoff value and the pore radius r c The calculation formula converts the T2 cutoff value into the pore radius r. c ;

[0088] T2 cutoff value and pore radius r c The formula for calculation is:

[0089]

[0090] In the formula, ρ2 is the surface relaxation rate, which is a constant and varies depending on the lithology; F s is the pore shape factor, and is a constant.

[0091] Using the above formula, we can obtain that the T2 cutoff value for free pores and micropores corresponds to a pore radius limit of 0.6 μm; the T2 cutoff value for micropores and clay pores is 3 ms, corresponding to a pore radius of 0.1 μm.

[0092] In some embodiments, the step of determining the pore radius limits of free pores, micropores, and clay pores includes:

[0093] The pore components of the first resolution digital core, the second resolution digital core, and the clay component digital core were extracted respectively.

[0094] The pore structure of the pore components was analyzed using a pore mesh model to determine the pore radius boundaries of the free pores, micropores, and clay pores.

[0095] Specifically, for the first-resolution digital core, the second-resolution digital core, and the clay component digital core, the pore components of the digital core are extracted respectively, and the pore structure is analyzed using the pore mesh model to calculate the pore radius.

[0096] Example 2:

[0097] Based on the above embodiments, the method for determining the rock electrical parameters of the three-water model further includes:

[0098] The distribution of oil and water in the pores of the free-pore digital core was simulated to determine the rock resistivity index under different water saturation levels.

[0099] A cross-plot of resistivity index and water saturation was established, and the fourth rock electrical parameter of free pores was determined by fitting.

[0100] Based on the three-water model, the water saturation model in free pores is determined according to the first, second, third, and fourth rock electrical parameters.

[0101] In some examples, for digital cores with free pores, the distribution of oil and water in the pores is simulated using opening operations or the lattice Bohrman method. Numerical simulation is used to calculate the rock resistivity increase coefficient under different saturation levels, and a cross-plot of resistivity index versus water saturation (i.e., RI-S) is constructed. w (Intersection plot), fitted to obtain b f and n f ; among which; b f and n f This represents the fourth rock electrical parameter for free pores.

[0102] Specifically, since oil and gas exist only in free pore space, the resistivity numerical simulation of digital rocks with different saturation levels only needs to be performed on digital rocks with free pores. The resistivity index RI and water saturation S... w The simulation only needs to consider free pores; opening operations are used to simulate the oil-water distribution in free water pores, and corrosion operations are used to construct a water film to simulate the influence of crystal water; the resistivity of digital cores with different water saturation is simulated using finite element methods, the resistivity index RI is calculated, and RI-S is constructed. w The intersection plot was fitted to obtain b. f and n f .

[0103] In some embodiments, the method further includes:

[0104] The formation total water saturation model is determined based on the water saturation model in the free pores.

[0105] The water saturation of the reservoir is evaluated based on the total water saturation model of the formation.

[0106] In some examples, the first, second, third, and fourth rock electrical parameters are substituted into the three-water model, and the water saturation model in the free pores is obtained by transforming the following expression.

[0107]

[0108] The total water saturation model of the formation was further obtained using the water saturation model in free pores:

[0109]

[0110] The total water saturation model of the formation is applied to actual wells to evaluate the water saturation of the reservoir.

[0111] Example 3:

[0112] Based on the above embodiments, the steps of performing connectivity analysis on the first resolution digital core and the second resolution digital core, extracting the free pores and micropores of the first resolution digital core and the second resolution digital core according to the pore radius boundaries of free pores, micropores and clay pores, constructing digital cores containing free pores and digital cores containing micropores, and extracting clay pores from the clay component digital core to construct a wet clay digital core further include:

[0113] The definition of free pores includes all pores in the second resolution digital core and connected pores with a pore radius greater than 0.6 μm in the first resolution digital core;

[0114] The micropores are defined as isolated pores in the first resolution digital core and interconnected pores with pore radii between 0.1 μm and 0.6 μm.

[0115] In addition, it is determined that the clay pores include the pores in the digital core of the clay component.

[0116] Specifically:

[0117] (1) Free pores.

[0118] When the scanning resolution is 2μm, only pores with a size larger than 2μm can be identified. Therefore, a higher resolution (0.03μm) scanning image is needed to classify the pores. It is important to emphasize that if only a single resolution of 0.03μm is used for scanning, due to the 600×600×600 voxel size of the digital core, pores with a size larger than 18μm (0.03×600μm) cannot be identified, even though pores larger than 18μm are abundant in rocks. The pore sizes in a 2μm resolution digital core are all greater than or equal to 2μm and should be considered free pores.

[0119] For digital core samples with a resolution of 0.03 μm, the identifiable pore sizes range from 0.03 to 18 μm. Clearly, at this resolution, free pores, micropores, and clay pores coexist in the identified pores. After removing the clay portion, connectivity analysis is performed on all pores to extract connected pores. Connected pores with a radius greater than 0.6 μm are identified as free pores.

[0120] In summary, free pores consist of two parts: all pores in the 2μm resolution digital core and connected pores with a pore radius greater than 0.6μm in the 0.03μm digital core.

[0121] (2) Micropores.

[0122] The pore radius of the microporous component ranges from 0.1 to 0.6 μm, and this portion of pores is extracted from digital cores constructed using high-resolution (0.03 μm) scanning. Connected pores with pore radii between 0.1 and 0.6 μm are classified as micropores. Furthermore, isolated pores have a certain influence on the electrical conductivity of rocks. Although isolated pores are not interconnected, they acquire conductivity when connected to connected pores, clay, etc., to form a network. Similar to microporous water, water in isolated pores cannot flow or be produced, and its conductivity is consistent with formation water, unlike clay water. Therefore, isolated pores should also be classified as micropores.

[0123] In summary, micropores consist of two parts: interconnected pores with pore radii between 0.1 and 0.6 μm and all isolated pores.

[0124] (3) Clay pores.

[0125] A pore structure analysis was performed on the digital core sample of the clay portion (resolution 10 nm), and the extracted pores were identified as clay pores.

[0126] The pore radius distribution of each component was determined using the method described above. Figure 1As shown, free pores, micropores, and clay pores were extracted according to the pore radius boundaries of 0.6 μm and 0.1 μm, respectively. Pores with a pore radius greater than 0.6 μm were identified as free water pores, pores with a pore radius between 0.1 μm and 0.6 μm and isolated pores were identified as micropores, and the pores extracted from the pure clay portion were identified as clay pores.

[0127] In summary, the radius distribution of free pores, micropores, and clay pores is shown in Table 1.

[0128] Table 1 Distribution of free pores, micropores, and clay pore radii

[0129] Free pores micropores Clay water pores Pore ​​radius (μm) >0.6 0.1～0.6 <0.1

[0130] In this embodiment, a specific region is used as an example to illustrate the determination of the pore radii of free pores, micropores, and clay pores. In other embodiments, the size ranges of free pores, micropores, and clay pores are different depending on the specific conditions of different regions.

[0131] Example 4:

[0132] Based on the above embodiments, the step of performing numerical simulations on the digital cores containing free pores, microporous digital cores, and wet clay digital cores respectively to obtain the first stratigraphic factor of the free pore digital rock, the second stratigraphic factor of the microporous digital rock, and the third stratigraphic factor of the clay-porosity digital rock includes:

[0133] The digital cores containing free pores, micropores, and wet clay were respectively fully saturated with water.

[0134] The resistivity of the digital core containing free pores, the digital core containing micropores, and the digital core containing wet clay when fully saturated with water was simulated using the finite element method.

[0135] The first stratigraphic factor of the free-pore digital rock, the second stratigraphic factor of the microporous digital rock, and the third stratigraphic factor of the clay-porous digital rock were determined based on the resistivity of the digital core containing free pores, the digital core containing microporous rocks, and the digital core containing wet clay when fully saturated with water.

[0136] Specifically, considering the conductivity of each part of the digital core containing free pores, the digital core containing micropores, and the digital core containing wet clay, the constructed digital cores containing free pores, micropores, and wet clay are fully saturated with water. The resistivity of the digital cores containing free pores, micropores, and clay is simulated using the finite element method when they are fully saturated with water. Based on the resistivity of the digital cores containing free pores, micropores, and clay when they are fully saturated with water, the first stratigraphic factor of the free pore digital rock, the second stratigraphic factor of the micropore digital rock, and the third stratigraphic factor of the clay porous digital rock are determined.

[0137] Furthermore, based on stratigraphic factors and porosity, stratigraphic factor-porosity cross plots (i.e., F-φ cross plots) were constructed for free-porosity digital rocks, microporous digital rocks, and wet clay digital rocks, respectively, and the rock electrical parameters a of the three parts were fitted. f and m f a i and m i a c and m c Specifically, based on a first cross-plot of the first stratigraphic factor and the first porosity, the first rock electrical parameter corresponding to the free pores is determined; based on a second cross-plot of the second stratigraphic factor and the second porosity, the second rock electrical parameter corresponding to the micropores is determined; and based on a cross-plot of the third stratigraphic factor and the third porosity, the third rock electrical parameter corresponding to the clay pores is determined; where F is the stratigraphic factor, F... f F i and F c These refer to the stratigraphic factors of free-porosity digital rocks, microporous digital rocks, and wet clay digital rocks, respectively; similarly, φ represents porosity. f It is the porosity of free water; φ i It refers to the porosity of microporous water; φ c It refers to the water porosity of clay; and a and m are used to refer to rock electrical parameters, a f and m f Rock electrical parameters used to refer to free pores; a i and m i Rock electrical parameters used to refer to micropores; a c and m c Rock electrical parameters used to refer to the pore size of clay.

[0138] High-resolution scanning was performed on the clay fraction to construct a digital core of the clay. The porosity calculated for the clay fraction is not the true porosity of the clay and needs to be recalculated on an equivalent low-resolution digital core. The calculation method is as follows:

[0139] φ cl =φ′cl V cl

[0140] In the formula, φ cl It represents the porosity of the clay portion, as a decimal; φ' cl This is the porosity of the pure clay portion of the digital core, decimal, V. cl It is the volumetric content of clay components in low-resolution digital core samples, in decimal form.

[0141] The free water-containing rock component contains two parts of pores, and its total porosity is:

[0142] φ tf =φ1+φ2

[0143] In the formula, φ tf φ1 is the total porosity of rock components containing free water, a decimal; φ2 is the porosity of rock components containing free water at low resolution, i.e., pore size greater than 2μm, a decimal; φ3 is the porosity of rock components containing free water at high resolution, i.e., pore size less than 2μm, a decimal.

[0144] The equivalent resistivity of rock components containing free water is calculated by the following formula:

[0145]

[0146] In the formula, R eq R1 is the equivalent resistivity of rocks containing free water, in Ω·m; R2 is the resistivity of low-resolution rocks containing free water, i.e., pore size greater than 2μm, in Ω·m; R3 is the resistivity of high-resolution rocks containing free water, i.e., pore size less than 2μm, in Ω·m.

[0147] In numerical simulations, the resistivity R of free water and microporous water is... w The results are the same, both obtained from formation water analysis experiments; the conductivity of clay water considers the influence of the electric double layer, and the conductivity of clay water is calculated according to the DW model theory.

[0148]

[0149] In the formula, C cw Here, f(φ) represents the electrical conductivity of clay in water, in S / m. cw f(φ) represents the proportion of water in the pore volume of clay. cw＝ αV Q Q v β is the specific conductivity of the compensating cation; (S / m) (mmol / mL); V Q α is the pore volume occupied by clay water, mL / mmol; α is the diffusion layer expansion factor, usually taken as 1.

[0150] The constructed digital cores containing free pores, micropores, and wet clay were fully saturated with water. The resistivity of the three parts of the digital rock under saturation was simulated using the finite element method. The formation factor F was calculated, and F-φ cross plots were constructed for the free pore, micropore, and clay parts, respectively. The a value was then fitted. f and m f a i and m i a w and m w .

[0151] Example 5:

[0152] The method for determining the rock electrical parameters of the three-water model in this embodiment can be applied to electronic devices with communication, computing, and data storage capabilities. Its specific process can be as follows: Figure 2 and Figure 3 As shown, it includes:

[0153] Step A: Select representative core samples from reservoir locations and perform micron-CT scans at different resolutions to construct low-resolution 3D digital cores and high-resolution 3D digital cores; select pure clay locations and perform nano-CT scans to construct clay component 3D digital cores; calculate the pore radius for each.

[0154] Specifically, core samples were selected for micro / nano CT scanning at different resolutions, with resolutions of 2 μm and 0.03 μm. Pure mudstone portions of the samples were selected for high-resolution nano CT scanning at a resolution of 10 nm. Digital cores were constructed for each sample, with dimensions of 600×600×600 voxels. Figure 4 As shown, the number of CT scan samples at each resolution is 5.

[0155] In some examples, for 3D digital cores with three different resolutions, the pore components of the digital cores are extracted, and the pore structure is analyzed using a pore mesh model to calculate the pore radius.

[0156] Step B: Determine the pore radius boundaries of free pores and micropores, and micropores and clay pores.

[0157] Specifically, rocks contain free pores, micropores, and clay pores simultaneously. Nuclear magnetic resonance (NMR) experiments can determine the T2 cutoff values ​​for free pores and micropores. Previous experiments have shown that the T2 cutoff value for micropores and clay pores is 3 ms. Taking dense sandstone as an example, NMR experiments have determined the T2 cutoff value for free pores and micropores to be 20 ms.

[0158] The T2 cutoff value is converted into the pore radius r using equation (3). c ;

[0159]

[0160] In the formula, ρ2 is the surface relaxation rate, which is a constant and varies depending on the lithology; F s is the pore shape factor, and is a constant.

[0161] Using the above formula, we can obtain that the T2 cutoff value of free pores and micropores in sandstone is 20ms, and the pore radius limit corresponding to the T2 cutoff value of free pores and micropores is 0.6μm; the T2 cutoff value of micropores and clay pores is 3ms, and the corresponding pore radius is 0.1μm.

[0162] Step C involves conducting connectivity analysis on digital cores of different resolutions and extracting free pores, micropores, and clay pores using pore radius limits.

[0163] Specifically, connectivity analysis was conducted on digital cores at different resolutions, and free pores, micropores, and clay pores were extracted from the digital cores at different resolutions using pore radius boundaries. Among them, isolated pores belong to the micropore component.

[0164] Connected pores with a pore radius greater than 0.6 μm are classified as free pores, while connected pores and isolated pores with pore radii between 0.1 μm and 0.6 μm are classified as micropores. The pores extracted from the pure clay fraction are classified as clay pores. Specifically:

[0165] (1) Free pores.

[0166] When the scanning resolution is 2μm, only pores with a size larger than 2μm can be identified. Therefore, a higher resolution (0.03μm) scanning image is needed to classify the pores. It is important to emphasize that if only a single resolution of 0.03μm is used for scanning, due to the 600×600×600 voxel size of the digital core, pores with a size larger than 18μm (0.03×600μm) cannot be identified, even though pores larger than 18μm are abundant in rocks. The pore sizes in a 2μm resolution digital core are all greater than or equal to 2μm and should be considered free pores.

[0167] For digital core samples with a resolution of 0.03 μm, the identifiable pore sizes range from 0.03 to 18 μm. Clearly, at this resolution, free pores, micropores, and clay pores coexist in the identified pores. After removing the clay portion, connectivity analysis is performed on all pores to extract connected pores. Connected pores with a radius greater than 0.6 μm are identified as free pores.

[0168] In summary, free pores consist of two parts: all pores in the 2μm resolution digital core and connected pores with a pore radius greater than 0.6μm in the 0.03μm digital core.

[0169] (2) Micropores.

[0170] The pore radius of the microporous component ranges from 0.1 to 0.6 μm, and this portion of pores is extracted from digital cores constructed using high-resolution (0.03 μm) scanning. Connected pores with pore radii between 0.1 and 0.6 μm are classified as micropores. Furthermore, isolated pores have a certain influence on the electrical conductivity of rocks. Although isolated pores are not interconnected, they acquire conductivity when connected to connected pores, clay, etc., to form a network. Similar to microporous water, water in isolated pores cannot flow or be produced, and its conductivity is consistent with formation water, unlike clay water. Therefore, isolated pores should also be classified as micropores.

[0171] In summary, micropores consist of two parts: interconnected pores with pore radii between 0.1 and 0.6 μm and all isolated pores.

[0172] (3) Clay pores.

[0173] A pore structure analysis was performed on the digital core sample of the clay portion (resolution 10 nm), and the extracted pores were identified as clay pores.

[0174] The pore radius distribution of each component was determined using the method described above. Figure 3 As shown, free pores, micropores, and clay pores were extracted according to the pore radius boundaries of 0.6 μm and 0.1 μm, respectively. Pores with a pore radius greater than 0.6 μm were identified as free water pores, pores with a pore radius between 0.1 μm and 0.6 μm and isolated pores were identified as micropores, and the pores extracted from the pure clay portion were identified as clay pores.

[0175] Table 1 Distribution of free pores, micropores, and clay pore radii

[0176] Free pores micropores Clay water pores Pore ​​radius (μm) >0.6 0.1～0.6 <0.1

[0177] Digital cores containing free pores, micropores, and wet clay were constructed, and their pore spaces were extracted as follows: Figure 5 As shown.

[0178] Step D: Considering the conductivity of each part individually, numerical simulations are conducted for free-pore digital rock, microporous digital rock, and wet clay digital rock respectively; the stratigraphic factors of water-saturated rock are calculated, and F-φ cross plots are constructed for the three parts to fit the rock electrical parameter a. f and m f a i and m i a c and m.

[0179] Specifically, high-resolution scanning is performed on the clay fraction to construct a digital core of the clay. The porosity calculated for the clay fraction is not the true porosity of the clay and needs to be recalculated on an equivalent low-resolution digital core. The calculation method is as follows:

[0180] φ cl =φ′ cl V cl (4)

[0181] In the formula, φ cl It represents the porosity of the clay portion, as a decimal; φ' cl This is the porosity of the pure clay portion of the digital core, decimal, V. cl It is the volumetric content of clay components in low-resolution digital core samples, in decimal form.

[0182] The free water-containing rock component contains two parts of pores, and its total porosity is:

[0183] φ tf =φ1+φ2 (5)

[0184] In the formula, φ tf φ1 is the total porosity of rock components containing free water, a decimal; φ2 is the porosity of rock components containing free water at low resolution, i.e., pore size greater than 2μm, a decimal; φ3 is the porosity of rock components containing free water at high resolution, i.e., pore size less than 2μm, a decimal.

[0185] The equivalent resistivity of rock components containing free water is calculated by the following formula:

[0186]

[0187] In the formula, R eq R1 is the equivalent resistivity of rocks containing free water, in Ω·m; R2 is the resistivity of low-resolution rocks containing free water, i.e., pore size greater than 2μm, in Ω·m; R3 is the resistivity of high-resolution rocks containing free water, i.e., pore size less than 2μm, in Ω·m.

[0188] In numerical simulations, the resistivity R of free water and microporous water is... w The results are the same, both obtained from formation water analysis experiments; the conductivity of clay water considers the influence of the electric double layer, and the conductivity of clay water is calculated according to the DW model theory.

[0189]

[0190] In the formula, C cw Here, f(φ) represents the electrical conductivity of clay in water, in S / m. cw f(φ) represents the proportion of water in the pore volume of clay. cw =αV Q Q vβ is the specific conductivity of the compensating cation; (S / m) (mmol / mL); V Q α is the pore volume occupied by clay water, mL / mmol; α is the diffusion layer expansion factor, usually taken as 1.

[0191] The constructed digital cores containing free pores, micropores, and wet clay were fully saturated with water. The resistivity of the three parts of the digital rock under saturation was simulated using the finite element method. The formation factor F was calculated, and F-φ cross plots were constructed for the free pore, micropore, and clay parts, respectively. The a value was then fitted. f and m f a i and m i a w and m w .

[0192] See appendix Figure 6 The resistivity of digital cores containing free pores, micropores, and wet clay under fully saturated water conditions was simulated, and the formation factor F was calculated to construct F-φ cross plots. The F-φ cross plots of the three types of digital cores showed good correlation between F and φ. The lithology coefficient and cementation index of the three types of digital cores were obtained by fitting the plots: a f =0.97, m f =2.15; a i =1.03, m i =3.24; a c =1.04; m c =1.74.

[0193] Step E: For digital rocks with free pores, the oil-water distribution in the pores is simulated using opening operations or the lattice Boltzmann method. The rock resistivity increase coefficient under different saturation levels is calculated using numerical simulation, and an RI-S model is constructed. w The intersection plot was fitted to obtain b. f and n f .

[0194] Specifically, since oil and gas exist only in free pore space, the resistivity numerical simulation of digital rocks with different saturation levels only needs to be performed on digital rocks with free pores. The resistivity index RI and water saturation S... w The simulation only needs to consider free pores; opening operations are used to simulate the oil-water distribution in free water pores, and corrosion operations are used to construct a water film to simulate the influence of crystal water; the resistivity of digital cores with different water saturation is simulated using finite element methods, the resistivity index RI is calculated, and RI-S is constructed. w The intersection plot was fitted to obtain b. f and n f See appendix. Figure 7 Through fitting, we obtain: b f =0.92, nf =1.23.

[0195] The rock electrical parameters of rocks with free pores, rocks with micropores, and wet clay determined in this embodiment are shown in Table 2.

[0196] Table 2. Rock electrical parameters of each component of the "three waters" model determined based on digital core samples.

[0197] Rocks containing free water Rocks containing micropores clay part a 0.97 1.03 1.04 m 2.15 3.24 1.74 b 0.92 - - n 1.23 - -

[0198] Step F: Substitute the rock electrical parameters obtained in steps D and E into the three-water model, and transform them using equation (1) to obtain the water saturation model in the free pores.

[0199]

[0200] Step G: The total formation water saturation model is further obtained using the water saturation model in free pores.

[0201]

[0202] The total water saturation model of the formation is applied to actual wells to evaluate the water saturation of the reservoir.

[0203] In this embodiment, a novel approach is proposed to determine the rock electrical parameters in a "three-water" model based on multi-resolution digital core technology. Using pore radius as the standard, free pore, micropore, and clay pore components are extracted from digital cores of different resolutions, constructing digital cores containing free pores, micropores, and wet clay, respectively. Then, considering the conductivity mechanism of each component separately, numerical simulations are used to construct F-φ cross plots and RI-S plots for digital cores containing different pore sizes. w The cross-plot was used to obtain the rock electrical parameters of the three parts of the "three-water" model through fitting. This embodiment achieves accurate determination of key parameters of the "three-water" model and calculation of reservoir saturation, and can be extended to any type of reservoir.

[0204] Example 6:

[0205] Another embodiment of this application relates to a method for determining key parameters of a three-water model based on multi-resolution digital core data, applied to a key exploration well. The method for determining the key parameters of the three-water model based on multi-resolution digital core data is as described in Embodiment 5 above, and will not be repeated here. The saturation is evaluated using the three-water model parameters determined in Embodiment 5. Figure 8 This is a diagram showing the saturation evaluation results of the well.

[0206] The figure shows the following: the first channel is the depth channel; the second channel shows natural gamma ray logging, spontaneous potential, and wellbore diameter; the third channel shows compensated density logging, compensated neutron logging, sonic transit time, and photoelectric absorption cross-section index; the fourth channel shows array induced resistivity; the fifth channel shows the T2 distribution of nuclear magnetic resonance logging; the sixth channel shows the porosity of free water, micropore water, and clay water calculated by nuclear magnetic resonance logging; the seventh channel compares the oil saturation calculated using the parameters determined in Example 1 with the saturation calculated using the porosity lower limit method; the black dots represent the saturation from closed coring experiments; and the eighth channel shows the mineral profile. As can be seen from the figure, the oil saturation calculated using the parameters determined in Example 1 matches well with the saturation from closed coring experiments, proving that the key parameters of the proposed "three-water" model determined based on digital rock physics technology are accurate.

[0207] Example 7:

[0208] Another embodiment of this application relates to a device for determining the electrical parameters of a three-water model rock. The implementation details of determining the electrical parameters of a three-water model rock in this embodiment are described below. The following details are provided for ease of understanding and are not essential for implementing this solution. A schematic diagram of determining the electrical parameters of a three-water model rock in this embodiment can be seen as follows: Figure 9 As shown, it includes an acquisition module 801, a construction module 802, a numerical simulation module 803, and a rock electrical parameter determination module 804.

[0209] The acquisition module 801 is used to acquire a first-resolution digital core, a second-resolution digital core, and a clay component digital core of a pure clay sample, wherein the first resolution is higher than the second resolution.

[0210] The construction module 802 is used to perform connectivity analysis on the first resolution digital core and the second resolution digital core, and extract the free pores and micropores of the first resolution digital core and the second resolution digital core according to the pore radius boundaries of free pores, micropores and clay pores, to construct digital cores containing free pores and digital cores containing micropores, and to extract the clay pores of the clay component digital core to construct wet clay digital cores.

[0211] The numerical simulation module 803 is used to perform numerical simulations on the digital core containing free pores, the digital core containing micropores, and the digital core containing wet clay, respectively, to obtain the first stratigraphic factor of the digital rock containing free pores, the second stratigraphic factor of the digital rock containing micropores, and the third stratigraphic factor of the digital rock containing clay pores.

[0212] The rock electrical parameter determination module 804 is used to determine the first porosity of free pores, the second porosity of micropores, and the third porosity of clay pores, and to determine the first rock electrical parameter corresponding to free pores based on the first cross-plot of the first formation factor and the first porosity, to determine the second rock electrical parameter corresponding to micropores based on the second cross-plot of the second formation factor and the second porosity, and to determine the third rock electrical parameter corresponding to clay pores based on the cross-plot of the third formation factor and the third porosity.

[0213] It is worth mentioning that all modules involved in this embodiment are logical modules. In practical applications, a logical unit can be a physical unit, a part of a physical unit, or a combination of multiple physical units. Furthermore, to highlight the innovative aspects of this application, this embodiment does not introduce units that are not closely related to solving the technical problems proposed in this application; however, this does not mean that other units are absent in this embodiment.

[0214] In the embodiments provided in this application, it should be understood that the disclosed apparatus and methods can also be implemented in other ways. The apparatus embodiments described above are merely illustrative. For example, the flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of apparatus, methods, and computer program products according to various embodiments of this disclosure. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code containing one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions marked in the blocks may occur in a different order than those marked in the drawings. For example, two consecutive blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in a block diagram and / or flowchart, and combinations of blocks in block diagrams and / or flowcharts, can be implemented using a dedicated hardware-based system that performs the specified function or action, or using a combination of dedicated hardware and computer instructions.

[0215] It should be noted that, in this disclosure, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element limited by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0216] Example 8:

[0217] Another embodiment of this application relates to an electronic device, such as... Figure 10 As shown, it includes: at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, the instructions being executed by the at least one processor to enable the at least one processor to implement the above method steps.

[0218] The memory and processor are connected via a bus, which can include any number of interconnecting buses and bridges, connecting various circuits of one or more processors and memories. The bus can also connect various other circuits, such as peripheral devices, voltage regulators, and power management circuits, which are well known in the art and will not be described further herein. The bus interface provides an interface between the bus and the transceiver. The transceiver can be a single element or multiple elements, such as multiple receivers and transmitters, providing a unit for communicating with various other devices over a transmission medium. Data processed by the processor is transmitted over the wireless medium via an antenna, which further receives data and transmits it to the processor.

[0219] The processor manages the bus and general processing, and also provides various functions, including timing, peripheral interfaces, voltage regulation, power management, and other control functions. Memory is used to store data used by the processor during operation.

[0220] The processor may include, but is not limited to, one or more processors or microprocessors. Each processor may be implemented as an Application Specific Integrated Circuit (ASIC), Digital Signal Processor (DSP), Digital Signal Processing Device (DSPD), Programmable Logic Device (PLD), Field Programmable Gate Array (FPGA), controller, microcontroller, microprocessor, or other electronic component, for executing the methods in the above embodiments.

[0221] Example 9:

[0222] Another embodiment of this application relates to a computer-readable storage medium storing a computer program. When executed by a processor, the computer program implements the above-described method steps.

[0223] That is, those skilled in the art will understand that all or part of the steps in the methods of the above embodiments can be implemented by a program instructing related hardware. This program is stored in a storage medium and includes several instructions to cause a device (which may be a microcontroller, chip, etc.) or processor to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0224] Computer-readable storage media may also store at least one computer-executable program / instruction, such as computer-readable instructions. Computer-readable storage media include, but are not limited to, volatile memory and / or non-volatile memory. Volatile memory may include, for example, random access memory (RAM) and / or cache memory. Computer-readable storage media may include, for example, read-only memory (ROM), hard disk, flash memory, etc. For example, a non-transitory computer-readable storage medium may be connected to a computing device such as a computer, and then, when the computing device executes the computer-readable instructions stored on the computer-readable storage medium, the various methods described above can be performed.

[0225] In addition, the computer device may include (but is not limited to) a data bus, an input / output (I / O) bus, a display, and input / output devices (e.g., keyboard, mouse, speakers, etc.).

[0226] The processor can communicate with external devices via the I / O bus through wired or wireless networks.

[0227] Those skilled in the art will understand that the above embodiments are specific embodiments for implementing this application, and in practical applications, various changes can be made to them in form and detail without departing from the spirit and scope of this application.

Claims

1. A method for determining the rock electrical parameters of a three-water model, characterized in that, include: First-resolution digital cores and second-resolution digital cores of rock samples, as well as digital cores of clay components of pure clay samples, are obtained, wherein the first resolution is higher than the second resolution. Connectivity analysis was performed on the first resolution digital core and the second resolution digital core. Based on the pore radius boundaries of free pores, micropores and clay pores, the free pores and micropores of the first resolution digital core and the second resolution digital core were extracted to construct digital cores containing free pores and digital cores containing micropores. Clay pores of the clay component digital core were extracted to construct wet clay digital cores. Numerical simulations were performed on the digital core containing free pores, the digital core containing micropores, and the digital core containing wet clay, respectively, to obtain the first stratigraphic factor of the digital rock containing free pores, the second stratigraphic factor of the digital rock containing micropores, and the third stratigraphic factor of the digital rock containing clay pores. The first porosity of free pores, the second porosity of micropores, and the third porosity of clay pores are determined. Based on the first cross-plot of the first stratigraphic factor and the first porosity, the first rock electrical parameter corresponding to free pores is determined. Based on the second cross-plot of the second stratigraphic factor and the second porosity, the second rock electrical parameter corresponding to micropores is determined. Based on the cross-plot of the third stratigraphic factor and the third porosity, the third rock electrical parameter corresponding to clay pores is determined.

2. The method for determining the rock electrical parameters of a three-water model according to claim 1, characterized in that, Also includes: The distribution of oil and water in the pores of the free-pore digital core was simulated to determine the rock resistivity index under different water saturation levels. A cross-plot of resistivity index and water saturation was established, and the fourth rock electrical parameter of free pores was determined by fitting. Based on the three-water model, the water saturation model in free pores is determined according to the first, second, third, and fourth rock electrical parameters.

3. The method for determining the rock electrical parameters of a three-water model according to claim 2, characterized in that, Also includes: The formation total water saturation model is determined based on the water saturation model in the free pores. The water saturation of the reservoir is evaluated based on the total water saturation model of the formation.

4. The method for determining the rock electrical parameters of a three-water model according to claim 1, characterized in that, The first resolution is 0.03 μm; the second resolution is 2 μm.

5. The method for determining the rock electrical parameters of a three-water model according to claim 4, characterized in that, The steps of performing connectivity analysis on the first-resolution digital core and the second-resolution digital core, extracting free pores and micropores from the first-resolution digital core and the second-resolution digital core based on the pore radius boundaries of free pores, micropores and clay pores, constructing digital cores containing free pores and digital cores containing micropores, and extracting clay pores from the clay component digital core to construct a wet clay digital core further include: The definition of free pores includes all pores in the second resolution digital core and connected pores with a pore radius greater than 0.6 μm in the first resolution digital core; The micropores are defined as isolated pores in the first resolution digital core and interconnected pores with pore radii between 0.1 μm and 0.6 μm. In addition, it is determined that the clay pores include the pores in the digital core of the clay component.

6. The method for determining the rock electrical parameters of a three-water model according to claim 1, characterized in that, The steps of performing connectivity analysis on the first-resolution digital core and the second-resolution digital core, extracting free pores and micropores from the first-resolution digital core and the second-resolution digital core based on the pore radius boundaries of free pores, micropores and clay pores, constructing digital cores containing free pores and digital cores containing micropores, and extracting clay pores from the clay component digital core to construct a wet clay digital core further include: The cutoff values ​​for free pores and micropores, as well as the cutoff values ​​for micropores and clay pores, were determined using nuclear magnetic resonance experiments. The pore radius limits of free pores, micropores, and clay pores are determined based on the cutoff values ​​of the free pores and micropores, as well as the cutoff values ​​of micropores and clay pores.

7. The method for determining the rock electrical parameters of a three-water model according to claim 1, characterized in that, The steps of performing numerical simulations on the digital cores containing free pores, micropores, and wet clay, respectively, to obtain the first stratigraphic factor of the free pore digital rock, the second stratigraphic factor of the micropore digital rock, and the third stratigraphic factor of the clay-porosity digital rock include: The digital cores containing free pores, micropores, and wet clay were respectively fully saturated with water. The resistivity of the digital core containing free pores, the digital core containing micropores, and the digital core containing wet clay when fully saturated with water was simulated using the finite element method. The first stratigraphic factor of the free-pore digital rock, the second stratigraphic factor of the microporous digital rock, and the third stratigraphic factor of the clay-porous digital rock were determined based on the resistivity of the digital core containing free pores, the digital core containing microporous rocks, and the digital core containing wet clay when fully saturated with water.

8. A device for determining the electrical parameters of a three-water model rock, characterized in that, include: The acquisition module is used to acquire first-resolution digital cores and second-resolution digital cores of rock samples, as well as clay component digital cores of pure clay samples, wherein the first resolution is higher than the second resolution. The module is used to perform connectivity analysis on the first resolution digital core and the second resolution digital core, and extract the free pores and micropores of the first resolution digital core and the second resolution digital core according to the pore radius boundaries of free pores, micropores and clay pores, to construct digital cores containing free pores and digital cores containing micropores, and to extract the clay pores of the clay component digital core to construct wet clay digital cores; The numerical simulation module is used to perform numerical simulations on the digital core containing free pores, the digital core containing micropores, and the digital core containing wet clay, respectively, to obtain the first stratigraphic factor of the digital rock containing free pores, the second stratigraphic factor of the digital rock containing micropores, and the third stratigraphic factor of the digital rock containing clay pores. The rock electrical parameter determination module is used to determine the first porosity of free pores, the second porosity of micropores, and the third porosity of clay pores. Based on the first cross-plot of the first stratigraphic factor and the first porosity, it determines the first rock electrical parameter corresponding to free pores, based on the second cross-plot of the second stratigraphic factor and the second porosity, it determines the second rock electrical parameter corresponding to micropores, and based on the cross-plot of the third stratigraphic factor and the third porosity, it determines the third rock electrical parameter corresponding to clay pores.

9. An electronic device, characterized in that, include: At least one processor; as well as, A memory communicatively connected to the at least one processor; wherein, The memory stores instructions that can be executed by the at least one processor to enable the at least one processor to perform the method for determining the rock electrical parameters of the three-water model as described in any one of claims 1 to 7.

10. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by the processor, it implements the method for determining the rock electrical parameters of the three-water model as described in any one of claims 1 to 7.

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