Method and system for characterizing size of nano oil displacement material and medium

Abstract

The invention discloses a characterization method and system for the size of a nanometer oil displacement material and a medium, and the characterization method comprises the following steps: preparing a corresponding simulation solution based on the salinity of an oil reservoir, and taking the simulation solution as a detection sample; carrying out refraction coefficient detection evaluation on the material of the detection sample and a plurality of preset solvents; the method comprises the following steps: carrying out multidirectional testing on a detection sample by using laser equipment, and representing the three-dimensional space size of particles in the detection sample; and based on the three-dimensional space size, evaluating the matching relationship between the detection sample and the corresponding reservoir microscopic pore throat. According to the method, the size of the nanoscale oil displacement medium is efficiently and accurately evaluated, technical support is provided for reasonably matching the oil displacement medium with the pore structure of the oil reservoir, the oil displacement medium suitable for the target oil reservoir is screened out, and therefore effective injection and efficient displacement are achieved, and the crude oil recovery rate is increased.

Description

Technical Field

[0001] The invention relates to the technical field of oil and gas exploitation, and in particular to a method, system and medium for characterizing the size of a nano oil-displacing material. Background Art

[0002] With the continuous deepening of oil and gas exploration and development, the development of oil and gas resources is becoming more and more difficult. First, most of the newly discovered reserves are unconventional, and their oil storage micro-pores are getting smaller and smaller; second, the remaining reserves of old oil fields are of poor quality, and the tertiary oil recovery technology requires high standards. During the mining process, the technical personnel who design the scheme need to have a more accurate grasp of the performance of the oil recovery medium. It is necessary to conduct in-depth research on the size of the oil recovery medium required by the micro-pores of the reservoir. And because of the special performance of some oil recovery media, the size of nano oil recovery agents is as low as nanometers, mainly because conventional water drives are difficult to reach and select crude oil in the micro-pores of low permeability and unconventional oil and gas reservoirs. Conventional methods are affected by equipment and means, and the lowest test can reach the micron level, but the accuracy is difficult to guarantee beyond this limit. Therefore, a method, system and medium for characterizing the size of nano oil recovery materials are needed. Summary of the invention

[0003] The embodiments of the present invention provide a method, system and medium for characterizing the size of nano oil-displacing materials, which at least partially solve the technical problem in the prior art that crude oil is difficult to reach and select in microscopic pores of low permeability and unconventional oil and gas reservoirs by conventional water flooding, and achieve the technical effects of achieving effective injection, efficient displacement and improving crude oil recovery.

[0004] In the first aspect, to solve the above technical problems, the embodiments of the present invention provide the following technical solutions:

[0005] A method for characterizing the size of a nano oil displacement material, comprising:

[0006] Prepare the corresponding simulated solution based on the reservoir salinity as the test sample;

[0007] Conducting refractive index testing and evaluation on the above-mentioned test sample materials and multiple preset solvents;

[0008] Using laser equipment to conduct multi-directional testing on the above-mentioned test sample to characterize the three-dimensional spatial size of the particles in the above-mentioned test sample;

[0009] Based on the above three-dimensional space dimensions, the matching relationship between the above test samples and the corresponding reservoir microscopic pore throats is evaluated.

[0010] Optionally, the step of evaluating the matching relationship between the test sample and the corresponding reservoir microscopic pore throats further includes:

[0011] Based on the three-dimensional spatial dimensions of different types of oil displacement media and the dimensions of microscopic pore throats in various reservoirs, fluidity experiments were conducted to obtain parameters that reflect the fluidity of the oil displacement media in the corresponding reservoirs;

[0012] Based on the above parameters, the test samples and reservoir microscopic pore throats that meet the preset requirements are screened as matching combinations to generate a matching table;

[0013] If the above-mentioned detection sample and the corresponding reservoir microscopic pore throat size meet any corresponding data in the adaptation table, the output evaluation is matched; otherwise, the output evaluation is not matched.

[0014] Optionally, the step of preparing a corresponding simulation solution based on the reservoir salinity may further include:

[0015] Using an ultrapure water instrument to prepare a preset volume of ultrapure water;

[0016] Based on the ultrapure water, simulated water is prepared according to the mineralization of the target block;

[0017] Filtering the simulated water using a filter membrane with a first preset pore size;

[0018] The filtered simulated water was prepared into the corresponding simulated solution.

[0019] Optionally, the step of preparing the filtered simulated water into a corresponding simulated solution further includes:

[0020] After adding the reagents required for the corresponding simulated solution into the simulated water, stirring is performed to obtain a primary simulated solution;

[0021] The primary simulated solution is placed in a centrifuge to separate liquid and solid particles;

[0022] The primary simulated solution after centrifugation is filtered using a filter membrane with a second preset pore size to obtain a final simulated solution.

[0023] Optionally, the step of characterizing the three-dimensional spatial size of the particles in the test sample further includes:

[0024] The final value is obtained by calculating the arithmetic average of the test results of the above laser equipment based on different orientations.

[0025] Optionally, before using the laser device to perform multi-directional testing on the test sample, the method further includes:

[0026] Calibrate the optical path of the above laser equipment until it is transparent, straight and noise-free.

[0027] Before using the laser device to perform a multi-directional test on the above-mentioned test sample, the above-mentioned method also includes:

[0028] Determine whether the light intensity of the above test sample meets the preset requirements. If so, proceed to the next step; otherwise, re-make the test sample.

[0029] Optionally, the step of using a laser device to perform a multi-directional test on the test sample further includes:

[0030] The dynamic and static scattering methods are used to conduct multi-directional tests on the above-mentioned test samples using lasers.

[0031] In a second aspect, a system for characterizing the size of a nano-scale oil displacement material is provided, comprising:

[0032] A matching liquid selection module is used to obtain data of any of the above-mentioned test sample materials and multiple preset solvents for refractive coefficient detection and evaluation;

[0033] A characterization module, used to obtain multi-directional test data of the above-mentioned laser equipment on the above-mentioned test sample, and characterize the three-dimensional spatial size of the particles in the above-mentioned test sample;

[0034] The evaluation module evaluates the matching relationship between the above-mentioned detection sample and the corresponding reservoir microscopic pore throat based on the above-mentioned three-dimensional space size.

[0035] In a third aspect, a computer-readable storage medium is provided, on which a computer program is stored, and when the program is executed by a processor, the steps corresponding to the above method in the first aspect are implemented.

[0036] One or more technical solutions provided in the embodiments of the present invention have at least the following technical effects or advantages:

[0037] Based on the established characterization method of oil displacement medium size, the size of nano-scale oil displacement medium is evaluated efficiently and accurately. The matching relationship between the corresponding oil displacement medium and the microscopic pore throat of the reservoir is evaluated through the characterization results, and the oil displacement medium suitable for the target reservoir is screened out, providing technical support for the reasonable matching of the oil displacement medium with the pore structure of the reservoir, so as to achieve effective injection, efficient displacement, and improve crude oil recovery. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. 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 creative work.

[0039] Figure 1 A flow chart of a method for characterizing the size of a nano oil-displacing material provided by the present invention;

[0040] Figure 2This is a test diagram of the silicon dioxide nano-oil displacement agent in the present invention;

[0041] Figure 3 A schematic diagram of the structure of a nano oil-displacing material size characterization system provided by the present invention. DETAILED DESCRIPTION

[0042] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0043] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. 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.

[0044] It should be noted that similar reference numerals and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further defined and explained in the subsequent drawings. In addition, the terms "first", "second", etc. are only used to distinguish the description and cannot be understood as indicating or implying relative importance.

[0045] It should be understood that the embodiments of the present invention and the specific features in the embodiments are detailed descriptions of the technical solutions of the present application, rather than limitations of the technical solutions of the present application. In the absence of conflict, the embodiments of the present application and the technical features in the embodiments may be combined with each other.

[0046] The technical solution of the embodiment of the present invention is to solve the above technical problems, and the overall idea is as follows:

[0047] First, a simulated solution is prepared to simulate the oil displacement medium to avoid interference from other reagents; then the refractive index is tested to determine the purity of the simulated solution. Finally, a laser device is used to perform multi-directional tests on the test sample to characterize the three-dimensional spatial size of the particles in the test sample; based on this size, the matching relationship between the oil displacement medium and the microscopic pore throat of the reservoir is evaluated.

[0048] In an embodiment of the present invention, there is provided Figure 1 A method for characterizing the size of a nano-scale oil displacement material is shown, the method comprising steps S101 to S104:

[0049] Step S101, preparing a corresponding simulated solution based on the reservoir salinity as a test sample;

[0050] It should be noted that in the configuration of the simulated solution, multiple filtrations are used to eliminate the influence of dust particles in the air on the matching liquid during the test. In detail, a preset volume of ultrapure water is prepared using an ultrapure water meter. In addition to water molecules, there are almost no impurities in ultrapure water, which avoids the interference of impurities. Then, simulated water is prepared according to the mineralization of the target block based on ultrapure water; the simulated water is filtered using a filter membrane; taking the first generation of silica nano oil-displacing agent as an example, a filter membrane with a pore size of 0.22μm is used. The filtered simulated water is prepared into the corresponding simulated solution. After adding the reagents required for the corresponding simulated solution to the simulated water, a magnetic stirrer is used to stir it to obtain a primary simulated solution; the silica nano oil-displacing agent aqueous solution is placed in a high-speed centrifuge with a speed of 8500r / min and a centrifugation time of 40min; the primary simulated solution is placed in a centrifuge to separate liquid and solid particles; the primary simulated solution after centrifugation is filtered using a filter membrane with a pore size of 2μm to obtain the final simulated solution. The sample pool is rinsed twice with acetone, and then turned upside down on the filter paper to dry.

[0051] Step S102, performing refractive index detection and evaluation on the test sample material and a plurality of preset solvents;

[0052] It should be noted that, considering the refraction of light at the two interfaces of solvent-sample cell and sample cell-reference solution, in order to reduce the impact of refraction, the refractive index of the sample cell material and solvents such as benzene, methanol, and decahydronaphthalene were tested and evaluated. Taking the silica nano-oil displacement agent as an example, the refractive index of the test sample and solvents such as acetone, ethanol, and decahydronaphthalene were tested and evaluated. After experimental testing, the refractive index of the sample cell was 1.5, decahydronaphthalene was 1.474, pure water was 1.333, acetone was 1.359, and ethanol was 1.361. Considering indoor conditions and safety, decahydronaphthalene solvents with similar refractive indices are preferred as matching liquids.

[0053] A decalin solvent with a similar refractive index is preferably used as the matching liquid.

[0054] Step S103, using laser equipment to perform multi-directional testing on the test sample to characterize the three-dimensional spatial size of particles in the test sample;

[0055] It should be noted that there are many ways to use laser equipment to perform size testing, such as testing at a fixed angle of incidence of 90 degrees, obtaining particle size parameters based on the Stokes-Einstein relationship equation, and selecting the radius of 79.9nm corresponding to the maximum frequency as the final value. The test results of silica nano-oil displacement agent are shown in Table 1 and Figure 2 shown.

[0056] Radius h(nm) Prime number accumulation Frequency 76.7 0.00 0.00 0 77.2 0.00 0.00 0 77.8 0.00 0.00 0 78.5 13.69 4.69 4.7 79.1 84.91 33.77 29.1 79.9 100 68.03 34.3 80.7 67.61 91.18 23.2 81.5 23.12 99.10 7.9 82.5 2.61 99.99 0.9 83.5 0.00 99.99 0 84.5 0.00 99.99 0

[0057] Table 1

[0058] The present embodiment is based on the dynamic and static scattering method, and uses laser equipment to test the test sample in a multi-directional manner, that is, different angles such as 0 degrees, 30 degrees, 45 degrees, 60 degrees and 90 degrees are used for testing. Among them, the dynamic light scattering method (Dynamic Light Scattering, DLS) can be used to test the size distribution of particles. By observing the optical scattering signal generated by the random unsteady Brownian motion of particles in the solution, the autocorrelation function of the particles is measured and analyzed to obtain the particle size information. The static light scattering method (Static Light Scattering, SLS) can be used to test the diameter of the particles. It depends on the concentration of particles in the solution, the particle radius and the molecular weight, measures the light intensity signal size of the scattering angle, and uses the corresponding theoretical formula to comprehensively analyze the signal to obtain relevant information such as the sample molecular weight.

[0059] Furthermore, the step of characterizing the three-dimensional spatial size of particles in the test sample also includes:

[0060] The final value is obtained by calculating the arithmetic average of the test results of the laser equipment at different orientations.

[0061] It should be noted that after multi-angle calculation, removing the arithmetic mean can effectively reduce the error caused by accidental factors, thereby achieving the effect of reducing the error and making the experimental results more accurate. The test results are shown in Table 2.

[0062] Angle of incidence Half angle of incidence sin(θ / 2) sin2(θ / 2) Diameter D(nm) Radius h(nm) 0 0 241 120.5 30 15 0.258 0.0669 233 116 45 22.5 0.382 0.146 216 108 60 30 0.500 0.250 192.7 96.4 90 45 0.707 0.500 158 79.9 average 208.1 104

[0063] Table 2

[0064] Based on the above Table 1, Table 2 and the physical data of the silica nano-oil displacement agent itself, it can be seen that multi-directional (also called multi-angle) testing is more in line with the actual situation.

[0065] Step S104, based on the three-dimensional space size, evaluating the matching relationship between the detected sample and the corresponding reservoir microscopic pore throat.

[0066] In detail, firstly, based on the three-dimensional spatial dimensions of different types of oil-displacing media and the dimensions of microscopic pore throats of various reservoirs, fluidity experiments are carried out to obtain parameters that reflect the fluidity of the oil-displacing media in the corresponding reservoirs; based on the parameter screening sequence, the test samples and reservoir microscopic pore throats that meet the preset requirements are used as an adaptation combination to generate an adaptation table; if the test sample and the corresponding reservoir microscopic pore throat dimensions meet any corresponding data in the adaptation table, the output evaluation is a match; otherwise, the output evaluation is a mismatch.

[0067] It should be noted that the particle size of the oil displacement medium for the effect and effect of the microscopic pore throat of the reservoir mainly refers to the permeability and fluidity of the oil displacement medium in the microscopic pore throat of the reservoir. If the particle size of the oil displacement medium is larger than the diameter of the microscopic pore throat of the reservoir, the permeability and fluidity of the oil displacement medium in the reservoir will be relatively poor, because the larger the ratio of the particle size to the diameter of the microscopic pore throat of the reservoir, the stronger the bridging or filling effect of the oil displacement medium in the reservoir, and vice versa. In addition, the particle size of the oil displacement medium may also affect the morphology and distribution of the microscopic pore throat of the reservoir, thereby affecting the oil displacement efficiency. If the particle size is large, the morphology of the microscopic pore throat of the reservoir may change, and the distribution is uneven, thereby reducing the oil displacement efficiency. Therefore, selecting an oil displacement medium of suitable size is of great significance for improving the oil displacement efficiency and oil recovery rate. Therefore, the present embodiment first carries out a fluidity experiment by carrying out a variety of corresponding data in a controlled variable manner, and the parameters of the fluidity of the oil displacement medium in the corresponding reservoir are reflected by data such as viscosity, interfacial tension between oil and water, and saturation. The test samples and reservoir microscopic pore throats that meet the mining requirements are taken as an adaptation combination to generate an adaptation table, and then an evaluation is performed based on the adaptation table.

[0068] Furthermore, before using the laser device to perform a multi-directional test on the test sample, the method also includes:

[0069] Calibrate the optical path of the laser device until it is transparent, straight and noise-free.

[0070] It should be noted that the purpose of this step is, firstly, to correct the error caused by laser refraction in the sample cell, by placing the sample cell in a matching liquid, allowing the light to first enter the matching liquid and then pass through the wall of the sample cell into the sample solution for correction; secondly, use a syringe to add decahydronaphthalene to the sample cell, turn on the filter pump switch for filtration, and the laser beam in the observation window will become uniform, clear and noise-free.

[0071] Furthermore, before using the laser device to perform multi-directional testing on the test sample, the method also includes: determining whether the light intensity of the test sample meets the preset requirements, if so, proceeding to the next step; otherwise, remaking the test sample.

[0072] It should be noted that the main purpose of measuring light intensity is to determine whether the quality of the optical fiber meets the experimental requirements. The light intensity can be measured by a photometer that measures lux or foot candles, thereby ensuring the accuracy of the experiment.

[0073] Based on the same inventive concept, the embodiment of the present invention provides a system for characterizing the size of nano oil displacement materials, such as Figure 3 As shown, including:

[0074] The matching liquid selection module is used to test the refractive index of any sample material and multiple preset solvents;

[0075] The characterization module is used to obtain the multi-directional test data of the laser equipment on the test sample and characterize the three-dimensional spatial size of the particles in the test sample;

[0076] The evaluation module evaluates the matching relationship between the detected samples and the corresponding reservoir microscopic pore throats based on the three-dimensional space dimensions.

[0077] Based on the same inventive concept, this embodiment provides a computer-readable storage medium having a computer program stored thereon, characterized in that when the program is executed by a processor, a method for characterizing the size of a nano-oil-displacing material is implemented.

[0078] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0079] Although the preferred embodiments of the present invention have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0080] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A method for characterizing the size of a nano-scale oil displacement material, characterized in that: The method comprises: Prepare the corresponding simulated solution based on the reservoir salinity as the test sample; Conducting refractive index testing and evaluation on the test sample material and a plurality of preset solvents; Using laser equipment to perform multi-directional testing on the test sample to characterize the three-dimensional spatial size of particles in the test sample; Based on the three-dimensional space size, the matching relationship between the detected sample and the corresponding reservoir microscopic pore throat is evaluated.

2. The method according to claim 1, characterized in that The step of evaluating the matching relationship between the test sample and the corresponding reservoir microscopic pore throats also includes: Based on the three-dimensional spatial dimensions of different types of oil displacement media and the dimensions of microscopic pore throats in various reservoirs, fluidity experiments were conducted to obtain parameters that reflect the fluidity of the oil displacement media in the corresponding reservoirs; Based on the parameter screening sequence, the test samples and reservoir microscopic pore throats that meet the preset requirements are used as an adaptation combination to generate an adaptation table; If the detection sample and the corresponding reservoir microscopic pore throat size meet any corresponding data in the adaptation table, the output evaluation is matched; otherwise, the output evaluation is not matched.

3. The method according to claim 1, characterized in that The step of preparing the corresponding simulation solution based on the reservoir salinity also includes: Using an ultrapure water instrument to prepare a preset volume of ultrapure water; Based on the ultrapure water, simulated water is prepared according to the mineralization of the target block; Filtering the simulated water using a filter membrane with a first preset pore size; The filtered simulated water was prepared into the corresponding simulated solution.

4. The method according to claim 3, characterized in that The step of preparing the filtered simulated water into a corresponding simulated solution also includes: After adding the reagents required for the corresponding simulated solution into the simulated water, stirring is performed to obtain a primary simulated solution; placing the primary simulated solution into a centrifuge to separate liquid and solid particles; The primary simulated solution after centrifugation is filtered using a filter membrane with a second preset pore size to obtain a final simulated solution.

5. The method according to claim 1, characterized in that The step of characterizing the three-dimensional spatial size of the particles in the test sample further includes: The final value is obtained by calculating the arithmetic average of the test results of the laser device at different orientations.

6. The method according to claim 1, characterized in that Before using the laser device to perform multi-directional testing on the test sample, the method further includes: Calibrate the optical path of the laser device until it is transparent, straight and noise-free.

7. The method according to claim 1, characterized in that Before using the laser device to perform multi-directional testing on the test sample, the method further includes: Determine whether the light intensity of the test sample meets the preset requirements. If so, proceed to the next step; otherwise, re-make the test sample.

8. The method according to claim 1, characterized in that The step of using laser equipment to perform multi-directional testing on the test sample also includes: The dynamic and static scattering methods are adopted and laser is used to carry out multi-directional testing on the detection sample.

9. A system for characterizing the size of nano-scale oil displacement materials, characterized in that: The system comprises: A matching liquid selection module, used to obtain data of the test sample material and a plurality of preset solvents as described in any one of claims 1 to 7, and to perform refractive coefficient detection and evaluation; A characterization module, used to obtain multi-directional test data of the laser device on the test sample, and characterize the three-dimensional spatial size of particles in the test sample; An evaluation module evaluates the matching relationship between the detection sample and the corresponding reservoir microscopic pore throat based on the three-dimensional space size.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the steps corresponding to the method according to any one of claims 1 to 7 are implemented.

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