Sandstone pore throat structure change quantitative evaluation method and system

Abstract

The invention relates to a sandstone pore throat structure change quantitative evaluation method and system, and belongs to the field of compact sandstone pore throat structures. The quantitative evaluation method comprises the following steps: obtaining rock pore throat change characteristic parameters based on result data after reaction of carbon dioxide and rock; based on the rock pore throat change characteristic parameters and the characteristic information of the rock sample, evaluation parameters of sandstone pore throat structure changes are obtained; and obtaining an evaluation result based on the evaluation parameters of the sandstone pore throat structure change and the characteristic information of the rock sample. According to the method, the microscopic pore throats can be represented in a graded and characteristic manner, the problem of strong interference of multiple collinear parts among parameters on a grading evaluation result during multi-parameter grading identification of the nano-micron pore throats is solved, the grading evaluation precision is further improved, the three-dimensional space pore throat structure characteristics of the tight sandstone reservoir are accurately and quantitatively represented, and the method is suitable for large-scale popularization and application. Therefore, classification and evaluation of microscopic pore throat features of different reservoirs are facilitated.

Description

Technical Field

[0001] The invention belongs to the field of tight sandstone pore throat structure, and in particular relates to a method and system for quantitatively evaluating changes in sandstone pore throat structure. Background Art

[0002] One of the notable characteristics of tight oil is that the reservoir is extremely dense, with extensive development of micron-nano pore throats, and nano-scale pore throats are dominant. Therefore, fine characterization of the micro-nanoscale pore throat system of tight reservoirs is the primary prerequisite for the effective development of this "black gold" of the petroleum industry. Tight sandstone reservoirs have the characteristics of poor physical properties, small pore throats, and strong microscopic heterogeneity, resulting in poor resource quality and strong economic sensitivity in development and utilization. They need to be developed in stages and types under relatively consistent economic and technical strategies. Pore throat structure is an important basic data in the process of oil field development. According to different experimental test methods, the pore throat structure research methods can be divided into direct and indirect methods. Direct methods include cast thin sections, scanning electron microscopy, CT scanning, etc.; indirect methods are mainly high-pressure mercury injection and constant-rate mercury injection.

[0003] For tight reservoirs, the pore throat scale is mainly micro-nano pores. Such pores are distributed in large quantities inside the reservoir, and there can be thousands of data sources in space. However, it is currently unable to meet the classification and evaluation of microscopic pore throat characteristics inside different tight sandstone reservoirs. Summary of the invention

[0004] In view of the above problems, the present invention provides a method and system for quantitatively evaluating changes in sandstone pore throat structure.

[0005] The first object of the present invention is to provide a method for quantitatively evaluating changes in sandstone pore throat structure, the method comprising:

[0006] Based on the result data after the reaction of carbon dioxide and rock, the characteristic parameters of rock pore throat change are obtained;

[0007] Based on the characteristic parameters of rock pore throat changes and the characteristic information of rock samples, the evaluation parameters of sandstone pore throat structure changes are obtained;

[0008] The evaluation results are obtained based on the evaluation parameters of the sandstone pore-throat structure changes and the characteristic information of the rock samples.

[0009] In the embodiment of the present invention, the rock pore throat change characteristic parameters obtained based on the result of the reaction between carbon dioxide and rock include:

[0010] The carbon dioxide reacts with the rock to obtain the result of the reaction of the carbon dioxide with the rock, wherein the concentration of the carbon dioxide and the reaction time are variable parameters, and the length, diameter, porosity, permeability and mass of the rock are fixed quantities;

[0011] Performing a first data processing on the result data of the reaction between carbon dioxide and rock;

[0012] Based on the data obtained by the first data processing, the rock pore throat change characteristic parameters are obtained.

[0013] In an embodiment of the present invention, the first data processing is performed according to the following formula:

[0014]

[0015] Where y is the response variable, c is a constant that makes y+c>0, and λ is the transformation parameter.

[0016] In the embodiment of the present invention, the variation parameter is calculated according to the following formula:

[0017]

[0018] Among them, y (λ) The formula representing the first data processing, Represents y 1 ,y 2 ,…y n The geometric mean

[0019] value, n is the observed value, I is the coefficient factor, and X is the eigenvector.

[0020] In an embodiment of the present invention, the rock pore throat variation characteristic parameters obtained based on the data obtained by the first data processing include:

[0021] Performing dimensionless processing on the data obtained by the first data processing;

[0022] Based on the data obtained by dimensionless processing, the characteristic parameters of rock pore throat changes are obtained.

[0023] In an embodiment of the present invention, the rock pore throat change characteristic parameters include structural seepage coefficient, displacement pressure, maximum pore throat radius, median pressure, median radius, mean coefficient, sorting coefficient, skewness coefficient, maximum mercury injection saturation, coefficient of variation, unsaturated mercury saturation, mean coefficient, residual mercury saturation, mercury withdrawal saturation, exit efficiency and pore throat ratio.

[0024] In the embodiment of the present invention, the evaluation parameters of the sandstone pore throat structure change are obtained based on the rock pore throat change characteristic parameters and the characteristic information of the rock sample, including:

[0025] Based on the characteristic information of rock samples, different types of rock samples are classified;

[0026] Based on different types of rock samples and characteristic parameters of rock pore throat changes, the evaluation parameters of sandstone pore throat structure changes were obtained.

[0027] In an embodiment of the present invention, the characteristic information of the rock sample includes length, diameter, porosity and permeability.

[0028] A second object of the present invention is to provide a quantitative evaluation system for sandstone pore throat structure changes, the evaluation system comprising:

[0029] The variation characteristic parameter extraction module is used to obtain the rock pore throat variation characteristic parameters based on the result data after the reaction of carbon dioxide and rock;

[0030] The evaluation parameter selection module is used to obtain the evaluation parameters of the sandstone pore throat structure change based on the rock pore throat change characteristic parameters and the characteristic information of the rock sample;

[0031] The evaluation module is used to obtain evaluation results based on the evaluation parameters of sandstone pore throat structure changes and the characteristic information of rock samples.

[0032] A third object of the present invention is to provide an electronic device, the electronic device comprising: a processor, the processor being coupled to a memory;

[0033] The memory is used to store computer programs;

[0034] The processor is used to execute the computer program stored in the memory so that the electronic device executes the method as described above.

[0035] A fourth object of the present invention is to provide a computer-readable storage medium, wherein the computer-readable storage medium includes a program or an instruction, and when the program or the instruction is executed on a computer, the computer executes the method as described above.

[0036] Beneficial effects of the present invention:

[0037] The present invention provides a method and system for quantitatively evaluating changes in sandstone pore throat structure. The method performs first data processing and dimensionless processing on result data after the reaction of carbon dioxide and rock to obtain characteristic parameters of rock pore throat changes. Then, among the characteristic parameters of rock pore throat changes, evaluation parameters of sandstone pore throat structure changes are screened according to characteristic information of rock samples, thereby realizing graded and characteristic characterization of microscopic pore throats. The method can solve the problem of strong interference of multiple collinear parts between parameters on graded evaluation results during multi-parameter graded identification of nano-micron pore throats, further improve the accuracy of graded evaluation, accurately and quantitatively characterize the three-dimensional spatial pore throat structure characteristics of tight sandstone reservoirs, and facilitate the classification and evaluation of microscopic pore throat characteristics of different reservoirs.

[0038] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures pointed out in the description, claims and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0040] Figure 1 A flow chart showing a method for quantitatively evaluating changes in sandstone pore throat structure according to an embodiment of the present invention is shown;

[0041] Figure 2 A framework diagram of a quantitative evaluation system for sandstone pore throat structure changes according to an embodiment of the present invention is shown;

[0042] Figure 3 A framework diagram of an electronic device according to an embodiment of the present invention is shown;

[0043] In the figure:

[0044] Change characteristic parameter extraction module 1; evaluation parameter selection module 2; evaluation module 3; electronic device 300; processor 301; memory 302. DETAILED DESCRIPTION

[0045] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0046] like Figure 1 As shown, a method for quantitatively evaluating changes in sandstone pore throat structure according to an embodiment of the present invention includes:

[0047] Step S1, based on the result data after the reaction of carbon dioxide and rock, obtain the characteristic parameters of rock pore throat change;

[0048] Step S2, obtaining evaluation parameters of sandstone pore throat structure changes based on rock pore throat change characteristic parameters and characteristic information of rock samples;

[0049] Step S3: obtaining evaluation results based on evaluation parameters of sandstone pore throat structure changes and characteristic information of rock samples.

[0050] In step S1, the rock pore throat change characteristic parameters are obtained based on the result of the reaction between carbon dioxide and rock, including:

[0051] Step A1, reacting carbon dioxide with rock to obtain the result of the reaction of carbon dioxide with rock, wherein the concentration of carbon dioxide and the reaction time are variable parameters, and the length, diameter, porosity, permeability and mass of the rock are fixed quantities;

[0052] Step A2, performing a first data processing on the result data of the reaction between carbon dioxide and rock;

[0053] Step A3: Based on the data obtained by the first data processing, obtain the rock pore throat change characteristic parameters.

[0054] Specifically, in step A1, the carbon dioxide reacts with the rock to obtain the result of the reaction of the carbon dioxide with the rock, wherein the concentration of the carbon dioxide and the reaction time are variable parameters, and the length, diameter, porosity, permeability and mass of the rock are fixed quantities, that is, by using an indoor test device, the reaction of different carbon dioxide concentrations with the rock samples for different times is studied to obtain the change data of the rock samples after the reaction;

[0055] The pore data and throat data are extracted from the rock sample change data after the reaction using a digital core model, and the pores are divided into effective pores and invalid pores according to the coordination number and the pore data. Then, the effective pores and invalid pores are subjected to a first data processing, i.e., step A2 operation is performed. The first data processing is performed according to formula (1):

[0056]

[0057] In formula (1), y is the reaction variable, which in this step is the rock sample change data after the reaction, such as the rock pore size data. The pore size change data are substituted into this formula for the first data processing, c is a constant to make y+c>0, and λ is a transformation parameter.

[0058] The variation parameter is calculated according to formula (2):

[0059]

[0060] In formula (2), y (λ) The formula representing the first data processing, Represents y 1 ,y 2 ,…y n The geometric mean of , n is the observed value, I is the coefficient factor, and X is the eigenvector.

[0061] Based on the operation of step A2, the data obtained by the first data processing is obtained, and the characteristic parameters of rock pore throat change are obtained, including:

[0062] Step B1, performing dimensionless processing on the data obtained by the first data processing;

[0063] Step B2: Based on the data obtained by dimensionless processing, obtain the characteristic parameters of rock pore throat changes.

[0064] Specifically, in step B1, the data obtained by the first data processing is dimensionlessly processed, and the specific processing is performed according to formula (3):

[0065]

[0066] In formula (3), x i To prepare the data for processing, is the mean of the corresponding data column, is the standard deviation, y i is the processed data;

[0067] After the dimensionless processing, the dimensionless processed data are obtained, and the characterization data of the rock sample change data after the reaction are obtained. At the same time, according to the influence of these characterization data and the carbon dioxide concentration or time, the rock pore throat change characteristic parameters are obtained, that is, the step B2 operation is performed;

[0068] The rock pore throat variation characteristic parameters include structural seepage coefficient, displacement pressure, maximum pore throat radius, median pressure, median radius, mean coefficient, sorting coefficient, skewness coefficient, maximum mercury injection saturation, coefficient of variation, unsaturated mercury saturation, mean coefficient, residual mercury saturation, mercury withdrawal saturation, withdrawal efficiency and pore throat ratio;

[0069] The permeability coefficient refers to the unit flow rate under unit hydraulic gradient in an isotropic medium. It indicates the difficulty of fluid passing through the pore skeleton. It is an indicator that comprehensively reflects the permeability of soil. It is also called hydraulic conductivity coefficient, with the symbol K. The correct determination of the value of the permeability coefficient is of great significance to the permeability calculation. Its size mainly depends on the shape, size, unevenness coefficient of soil particles and the viscosity of water.

[0070] The pore throat radius in the maximum pore throat radius is calculated by mercury injection method, that is, mercury injection experiment is carried out on the rock sample by high pressure mercury injection instrument PoreMaster, and the percentage of different pore throat interval volume in the total pore volume is calculated by the density, mass and porosity of the rock sample.

[0071] Mercury intrusion porosimetry, also known as mercury porosimetry, is a method for determining the pore size distribution of some mesopores and macropores. The basic principle is that mercury does not wet general solids. External pressure must be applied to make mercury enter the pores. The greater the external pressure, the smaller the pore radius that mercury can enter. By measuring the amount of mercury entering the pores under different external pressures, the pore volume of the corresponding pore size can be known.

[0072] The pore-throat ratio is the porosity ratio, which is the ratio of the pore volume in the soil to the volume of its solid particles. The porosity ratio is represented by e, which is an indicator of the structural characteristics of the soil. The smaller the e value, the denser the soil and the lower the compressibility; the larger the e value, the looser the soil and the higher the compressibility. The high compressibility of the soil indicates that the structural strength of the soil is poor, and the compression of the soil is large.

[0073] The calculation formula of void ratio e is (4):

[0074] or

[0075] In formula (4), or Among them, e is the void ratio of the clay body itself, n is the porosity of the clay, G s is the specific gravity of the cohesive soil, ρ a is the density of cohesive soil.

[0076] Porosity refers to the ratio of the pore volume inside the material to the total volume of the apparent volume of the granular material. Porosity includes true porosity, closed porosity and initial porosity. Porosity is related to the shape, structure and arrangement of the solid particles in the porous medium; it is an important parameter affecting the fluid transmission performance in the porous medium. Porosity (P) refers to the percentage of the pore volume inside the material to its total volume. Its calculation formula is (5):

[0077] P=[(V0-V) / V0]=[1-V / V0]=(1-P0 / P)×100% (5)

[0078] In formula (4), V0 is the volume of the material, V is the volume of the pores, and P0 is the apparent density of the material.

[0079] The relationship between porosity and density is shown in formula (6).

[0080] D+P=1 (6)

[0081] In formula (4), D is the density.

[0082] The porosity or density of a material directly reflects the density of the material. A high porosity indicates a low density. The calculation formula is shown in formula (7).

[0083] P0'=m / V0'=m / (V+VP+Vv) (7)

[0084] In formula (7), P0' is the bulk density of the material, kg / m 3 VP is the volume of the pores inside the particle, m 3 , Vv is the volume of the voids between particles, m 3 ;

[0085] The ratio of the sum of the volumes of all pore spaces in a rock sample to the volume of the rock sample is called the total porosity of the rock, expressed as a percentage. The larger the total porosity of the reservoir, the larger the pore space in the rock. The effective porosity refers to the ratio of the sum of the volumes of interconnected pores that allow fluid to flow under normal pressure conditions to the total volume of the rock sample, expressed as a percentage. The effective porosity of the same rock is less than its total porosity.

[0086] Definition of porosity in porous media: Porosity refers to the ratio of the total volume of tiny voids in a porous medium to the total volume of the porous medium. Its expression is shown in formula (8).

[0087]

[0088] In formula (7), is the porosity, V_P is the total volume of tiny voids, and V_B is the total volume of the porous medium.

[0089] Porosity can be divided into two types: the ratio of the total volume of interconnected tiny voids in a porous medium to the surface volume of the porous medium is called effective porosity, and the ratio of the total volume of interconnected tiny voids in a porous medium to the surface volume of the porous medium is called effective porosity. The ratio of the total volume of all interconnected and uninterconnected micro-voids in a porous medium to the surface volume of the porous medium is called absolute porosity or total porosity. Porosity usually refers to effective porosity, which is usually expressed as express.

[0090] In an embodiment of the present invention, after step S1, according to the result data after the reaction of carbon dioxide and rock, the first data processing and dimensionless processing are adopted to obtain the characteristic parameters of rock pore throat change, which can enrich the selection of evaluation parameters for sandstone density evaluation, and can solve the strong interference problem of multiple collinear parts between parameters on the classification evaluation results during multi-parameter classification identification of nano-micron pore throats, further improve the accuracy of classification evaluation, and accurately and quantitatively characterize the three-dimensional spatial pore throat structure characteristics of tight sandstone reservoirs, thereby facilitating the classification and evaluation of microscopic pore throat characteristics of different reservoirs.

[0091] In step S2, the evaluation parameters of the sandstone pore throat structure change are obtained based on the rock pore throat change characteristic parameters and the characteristic information of the rock sample, including:

[0092] Step D1, classifying different types of rock samples based on characteristic information of the rock samples;

[0093] Step D2: Based on different types of rock samples and rock pore throat variation characteristic parameters, evaluation parameters of sandstone pore throat structure variation are obtained.

[0094] Specifically, in step D1, a dense rock at a certain location is taken as a rock sample, and characteristic information of the rock sample is obtained, wherein the characteristic information of the rock sample includes length, diameter, porosity and permeability;

[0095] In the embodiment of the present invention, exemplarily, according to the size of the hole diameter, the holes on the rock sample are classified and graded, and specifically, a size threshold of the hole diameter is set. The size threshold can be flexibly divided according to the hole diameter data obtained from the rock sample, and can be set to one size threshold, another size threshold, or even more size thresholds. In the embodiment of the present invention, exemplarily, a size threshold is set to divide the holes on the rock sample into a first type of holes and a second type of holes, wherein the first type of holes includes surface caves and holes with a size greater than the size threshold, and the second type of holes includes holes with a size less than or equal to the size threshold;

[0096] After classification, the computational analysis steps are performed, namely:

[0097] Based on the characteristic data of the first type of holes, obtaining the mercury saturation of the first type of holes;

[0098] Based on the characteristic data of the second type of pores, a first capillary pressure curve of the rock sample is obtained, that is, the ratio of the volume of the second type of pores to the total pore volume of the rock sample;

[0099] Acquire a second capillary pressure curve based on the first capillary pressure curve, the mercury saturation of the first type of pores, and the characteristic data of the first type of pores;

[0100] Based on the second capillary pressure curve, the pore throat characteristic parameters in the rock sample are obtained. In this embodiment, the pore throat characteristic parameters include maximum pore radius, average pore radius, median, mean pore throat radius, sorting coefficient, skewness, peak state, and homogeneity coefficient;

[0101] The pore throat characteristic parameters and the rock pore throat change characteristic parameters (i.e., structural seepage coefficient, displacement pressure, maximum pore throat radius, median pressure, median radius, mean coefficient, sorting coefficient, skewness coefficient, maximum mercury injection saturation, coefficient of variation, unsaturated mercury saturation, mean coefficient, residual mercury saturation, mercury withdrawal saturation, withdrawal efficiency and pore throat ratio) are compared, and the average value of pore throat radius, median radius, mercury withdrawal efficiency, coefficient of variation and reservoir structure index are selected as evaluation parameters for quantitative evaluation of pore throat structure change of tight rock in the S area, that is, step D2 is completed;

[0102] In step S2, the second capillary pressure curve is obtained based on the first capillary pressure curve, the mercury injection saturation of the first type of pores and the characteristic data of the first type of pores; the first capillary pressure curve can reflect the characteristics of the second type of pores, and the mercury injection saturation and the characteristic data of the first type of pores can reflect the characteristics of the first type of pores, therefore, the second capillary pressure curve can simultaneously reflect the characteristics of the first type of pores and the second type of pores in the rock sample; it is ensured that the pore throat characteristic parameters obtained by the second capillary pressure curve can comprehensively characterize the changes in the pore throat structure of dense rock pores in a certain area, thereby improving the accuracy of quantitative evaluation of the changes in the pore throat structure of rock pores.

[0103] In step S3, the evaluation parameters based on the change of sandstone pore throat structure and the characteristic information of the rock sample are used to obtain the evaluation results;

[0104] Specifically, in the embodiment of the present invention, according to the evaluation parameters of the change of the sandstone pore throat structure determined in step S2, illustratively, according to the average throat radius, median radius, mercury removal efficiency, coefficient of variation, and reservoir structure index, the pore throat structure types of the dense rock in a certain S area are determined as 5 types, as shown in Table 1:

[0105] Table 1

[0106]

[0107]

[0108] Among them, the average value of pore throat radius / nm and the median radius are adopted (R is the average value of pore radius, μm).

[0109] Type I: coarse-extra-coarse pores and extra-coarse throats, the best reservoir type for tight sand layers, with an average pore throat radius of <10 and a permeability generally greater than 3500×10 -3 μm 2 , mercury removal efficiency is 1-8%, with an average of about 6%, reservoir structure index is 8-15, with an average of 8.0, pore throat distribution is well sorted, and there is a large platform section in the mercury injection curve;

[0110] Type II: coarse-extra-coarse pore and coarse throat type, which is a reservoir type with good dense sand layer, with an average pore throat radius of 10-70 and a permeability of 2000-3500×10 -3 μm 2 , mercury removal efficiency is 8-13%, with an average of about 9%, reservoir structure index is 5-9, with an average of 7.6, and the sorting of pore throat distribution is good;

[0111] Type III: coarse pores with medium throats, average pore throat radius of 70-120, and permeability of 1000-2000×10-3μm 2, mercury removal efficiency is 13-21%, with an average of 15.7%, reservoir structure index is 4-8, with an average of 4.7, strong heterogeneity, and the coefficient of variation is generally greater than 0.83;

[0112] Type IV: Medium pore and medium throat type, with an average pore throat radius of 120-150 and a permeability of 500-1000×10 -3 μm 2 The mercury removal efficiency is 21-33%, with an average of about 25%, and the reservoir structure index is generally less than 5.

[0113] V type: micropore and microthroat type, the average pore throat radius is >150, and the permeability is generally <500×10-3μm 2 , mercury removal efficiency is greater than 33%, reservoir structure index is less than 3, heterogeneity is strong, and the coefficient of variation is greater than 1.37.

[0114] According to the porosity and permeability data of dense rock samples in S area, Class I sandstone is distributed in the areas with porosity greater than 12% and permeability greater than 1.0×10 -3 μm 2 This boundary corresponds to the boundary between conventional reservoirs and tight reservoirs. Therefore, Type I sandstone is a conventional sandstone reservoir.

[0115] The porosity of Class II sandstone is between 9% and 12%, and the permeability is between 0.1 and 1.0×10 -3 μm 2 According to the oil and gas display in logging (according to the oil content level of CNPC cores / cuttings, from high to low, they are oil-bearing, oil-immersed, oil traces, oil spots, and fluorescence), the tight sandstone in this range is mainly oil-bearing, oil-immersed, and oil-trace display. Therefore, Class II sandstone can be defined as a high-quality tight reservoir.

[0116] The porosity of Class III sandstone is between 6% and 9%, and the permeability is between 0.05 and 0.1×10 -3 μm 2 The lower limit of oil content of tight reservoirs obtained by constant rate mercury injection is 6% porosity and 0.04×10 -3 μm 2 The oil and gas shows in the well logging show that the tight sandstone in this range is mainly composed of oil spots, so the Class III reservoir can be considered as an effective tight reservoir.

[0117] The porosity of Class IV sandstone is between 4% and 6%, and the permeability is between 0.01 and 0.05×10 -3 μm 2 , the tight sandstone in this range still has fluorescence display, so the tight sandstone in this range can still be classified as a reservoir, and is therefore defined as an inefficient tight reservoir.

[0118] The porosity of Class V sandstone is less than 4% and the permeability is less than 0.01×10-3 μm 2 , this type of sandstone is very dense and basically has no oil and gas. Although the dense sandstone with a porosity of less than 4% is mainly nanopores and still contains certain resources, due to the high development cost, great difficulty in economic mining, and poor resource quality, this type of sandstone is defined as a non-reservoir.

[0119] Based on the comprehensive evaluation of the upper and lower limits of tight reservoirs and the distribution characteristics of sandstone pore throats, a classification and evaluation standard for the layer physical properties of tight rocks in the S area was established, which was divided into five categories, including porosity between 4-12% and permeability between 0.01-1.0×10 -3 μm 2 , sandstone with pore throat radius less than 0.0004-0.4μm is defined as a tight reservoir, and the tight reservoir is divided into three categories: high-quality tight reservoir, effective tight reservoir and inefficient tight reservoir. The reservoir classification evaluation table is shown in Table 2:

[0120] Table 2

[0121]

[0122] like Figure 2 As shown, a quantitative evaluation system for sandstone pore throat structure changes according to some embodiments of the present invention includes:

[0123] The variation characteristic parameter extraction module 1 is used to obtain the rock pore throat variation characteristic parameters based on the result data after the reaction of carbon dioxide and rock;

[0124] The evaluation parameter selection module 2 is used to obtain the evaluation parameters of the sandstone pore throat structure change based on the rock pore throat change characteristic parameters and the characteristic information of the rock sample;

[0125] The evaluation module 3 is used to obtain evaluation results based on the evaluation parameters of the sandstone pore throat structure changes and the characteristic information of the rock samples.

[0126] like Figure 3 As shown, in some embodiments of the present invention, an electronic device 300 is provided, comprising: a processor 301, wherein the processor 301 is coupled to a memory 302;

[0127] The memory 302 is used to store computer programs;

[0128] The processor 301 is configured to execute the computer program stored in the memory 302 so that the electronic device executes the method in the above embodiment.

[0129] In some embodiments of the present invention, a computer-readable storage medium is provided, wherein the computer-readable storage medium includes a program or an instruction. When the program or the instruction is executed on a computer, the computer executes the method in the above-mentioned embodiments.

[0130] According to an embodiment of the present invention, the computer-readable storage medium may be a non-volatile computer-readable computer-readable storage medium, for example, may include but is not limited to: a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination thereof. In the present invention, a computer-readable storage medium may be any tangible medium containing or storing a program that may be used by or in combination with an instruction execution system, apparatus, or device.

[0131] Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent substitutions for some of the technical features therein; and these modifications or substitutions do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A quantitative evaluation method for sandstone pore throat structure changes, characterized in that: include: Based on the result data after the reaction of carbon dioxide and rock, the characteristic parameters of rock pore throat change are obtained; Based on the characteristic parameters of rock pore throat changes and the characteristic information of rock samples, the evaluation parameters of sandstone pore throat structure changes are obtained; The evaluation results are obtained based on the evaluation parameters of the sandstone pore throat structure changes and the characteristic information of the rock samples.

2. A quantitative evaluation method for sandstone pore throat structure changes according to claim 1, characterized in that: The rock pore throat change characteristic parameters obtained based on the result of the reaction between carbon dioxide and rock include: The carbon dioxide reacts with the rock to obtain the result of the reaction of the carbon dioxide with the rock, wherein the concentration of the carbon dioxide and the reaction time are variable parameters, and the length, diameter, porosity, permeability and mass of the rock are fixed quantities; Performing a first data processing on the result data of the reaction between carbon dioxide and rock; Based on the data obtained by the first data processing, the rock pore throat change characteristic parameters are obtained.

3. A method for quantitatively evaluating changes in sandstone pore throat structure according to claim 2, characterized in that: The first data processing is performed according to the following formula: Where y is the response variable, c is a constant that makes y+c>0, and λ is the transformation parameter.

4. A method for quantitatively evaluating changes in sandstone pore throat structure according to claim 3, characterized in that: The variation parameter is calculated according to the following formula: Among them, y (λ) The formula representing the first data processing, represents y1, y2, ...y n The geometric mean of , n is the observed value, I is the coefficient factor, and X is the eigenvector.

5. A method for quantitatively evaluating changes in sandstone pore throat structure according to claim 3, characterized in that: The data obtained based on the first data processing obtains the rock pore throat change characteristic parameters, including: Performing dimensionless processing on the data obtained by the first data processing; Based on the data obtained by dimensionless processing, the characteristic parameters of rock pore throat changes are obtained.

6. The method for quantitatively evaluating the change of sandstone pore throat structure according to claim 1, characterized in that: The rock pore throat variation characteristic parameters include structural seepage coefficient, displacement pressure, maximum pore throat radius, median pressure, median radius, mean coefficient, sorting coefficient, skewness coefficient, maximum mercury injection saturation, coefficient of variation, unsaturated mercury saturation, mean coefficient, residual mercury saturation, mercury withdrawal saturation, withdrawal efficiency and pore throat ratio.

7. A method for quantitatively evaluating changes in sandstone pore throat structure according to claim 1, characterized in that: The evaluation parameters of the sandstone pore throat structure change are obtained based on the rock pore throat change characteristic parameters and the characteristic information of the rock sample, including: Based on the characteristic information of rock samples, different types of rock samples are classified; Based on different types of rock samples and characteristic parameters of rock pore throat changes, the evaluation parameters of sandstone pore throat structure changes were obtained.

8. A method for quantitatively evaluating changes in sandstone pore throat structure according to any one of claims 1 to 7, characterized in that: The characteristic information of the rock sample includes length, diameter, porosity and permeability.

9. A quantitative evaluation system for sandstone pore throat structure changes, characterized in that: include: The variation characteristic parameter extraction module is used to obtain the rock pore throat variation characteristic parameters based on the result data after the reaction of carbon dioxide and rock; The evaluation parameter selection module is used to obtain the evaluation parameters of the sandstone pore throat structure change based on the rock pore throat change characteristic parameters and the characteristic information of the rock sample; The evaluation module is used to obtain evaluation results based on the evaluation parameters of sandstone pore throat structure changes and the characteristic information of rock samples.

10. An electronic device, characterized in that: include: a processor coupled to the memory; The memory is used to store computer programs; The processor is configured to execute the computer program stored in the memory, so that the electronic device executes the method according to any one of claims 1 to 8.

11. A computer-readable storage medium, characterized in that: The computer-readable storage medium includes a program or an instruction. When the program or the instruction is executed on a computer, the computer is caused to perform the method according to any one of claims 1 to 8.

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