A method and device for preparing a crude oil standard

Abstract

The present application belongs to the technical field of oil field crude oil testing, and particularly relates to a method and device for preparing a standard crude oil sample. The method for preparing a standard crude oil sample comprises sampling, preparing and testing a comparison test sample, and detecting and evaluating the density and water content of the comparison test sample from the aspects of uniformity testing and stability testing, so as to obtain a qualified standard crude oil sample. The present application fully considers the stability and uniformity of the crude oil sample, and can be used as a standard crude oil sample to carry out comparison work of water content and density among crude oil testing laboratories, improve the analysis and testing level of the crude oil testing laboratory, examine and evaluate the testing capacity of the laboratory, and improve the accuracy and reliability of the delivery detection data of the crude oil.

Description

Technical Field

[0001] This invention belongs to the field of oilfield crude oil testing technology, and specifically relates to a method and apparatus for preparing crude oil standard samples. Background Technology

[0002] Improving the testing capabilities of oilfield crude oil testing laboratories, including their ability to detect water content, density, and analytical levels, has been a focus of attention for engineering and management personnel. Timely evaluation and optimization of these capabilities are crucial for enhancing crude oil detection efficiency and reducing losses. Currently, the testing capabilities of oilfield crude oil testing laboratories, including their water content, density, and analytical levels, vary considerably, resulting in low accuracy and reliability of the handover testing data and contributing to some crude oil losses.

[0003] In the late 1990s, China National Petroleum Corporation (CNPC) promoted inter-laboratory comparative testing capabilities. Major oilfields conducted inter-laboratory comparisons of crude oil testing. These comparisons made the test data from different laboratories more accurate, reliable, and comparable, thus meeting the requirements for crude oil testing during oilfield production and sales. Currently, the tested sample is an indispensable carrier in inter-laboratory comparison activities; all activities revolve around the crude oil sample. Therefore, correctly selecting or preparing the crude oil sample is a crucial task. Ideally, using certified reference materials (CART) is most suitable for crude oil samples. However, due to the complexity of crude oil properties and the specificity of testing methods, there are currently no CART for crude oil density and water content. Therefore, conducting inter-laboratory crude oil testing, including comparisons of water content and density, cannot effectively improve the accuracy and reliability of crude oil testing data from laboratories. Summary of the Invention

[0004] To overcome the problem that the complex properties of existing crude oil and the special testing methods, as well as the lack of standard substances for crude oil density and water content, prevent the conduct of crude oil testing comparisons between oilfield laboratories, the purpose of this invention is to provide a method and apparatus for preparing crude oil standard samples. This method fully considers the stability and homogeneity of crude oil samples, enabling them to be used as crude oil standard samples for inter-laboratory comparisons of crude oil, improving the analytical testing level of crude oil testing laboratories, assessing and evaluating the testing capabilities of laboratories, and improving the accuracy and reliability of crude oil transfer testing data.

[0005] The technical solution of this invention is: a method for preparing crude oil standard samples, comprising the following steps:

[0006] S1: Sample taking for comparison test;

[0007] Crude oil samples with density and water content values ​​within the range of crude oil routinely tested in the participating comparative test laboratory were selected from the oilfield as density and water content comparative test samples.

[0008] S2: Preparation of the comparison test sample

[0009] The comparison test sample obtained in S1 is heated, stirred, and left to stand, and then is divided into containers as a comparison test sample to be tested, and is sealed and stored.

[0010] S3: Testing of the comparison test sample

[0011] The comparison test sample prepared in S2 is subjected to homogeneity testing and stability testing.

[0012] S4: If the homogeneity testing and stability testing in S3 are all qualified, the comparison test sample prepared in S2 is the crude oil standard sample.

[0013] In the sampling of the comparison test sample in S1, the water content of the crude oil selected in the oil field is emulsified water, and the water content is less than 0.2% by mass fraction, and the color of the crude oil is uniform, which is the crude oil after the crude oil stabilizing device.

[0014] S1: In the sampling of the comparison test sample, 120L of crude oil is selected in the oil field as the density and water content comparison test sample; in S2: Preparation of the comparison test sample, the comparison test sample is divided into 1000ml containers, a total of 100 bottles are divided, numbered from 001 to 100, and stored at room temperature.

[0015] In S2: Preparation of the comparison test sample, the heating temperature of the crude oil is between 30-40℃, the stirring time is 1 hour, and the standing time is 1 minute.

[0016] In S3: Homogeneity testing, N samples are randomly selected from the comparison test sample prepared in S2, N≥5, and the sample numbers are recorded; the homogeneity of the samples is tested by variance analysis, the water content and density of the crude oil are detected, and the detection results are recorded; when the F value of the detection result data is less than the F value obtained by looking up the table, the homogeneity of the comparison test sample prepared in S2 is qualified.

[0017] The formula of the variance analysis method in S3: Homogeneity testing is as follows:

[0018]

[0019]

[0020]

[0021]

[0022] v1=m-1 (5)

[0023] v2 = N-m (6)

[0024]

[0025] Wherein: Total average value; Q1 - between-group sum of squares; Q2 - within-group sum of squares; m - number of extracted samples; n - number of repeated tests of individual samples.

[0026] The stability test in S3 is described, and the specific process is as follows: N samples are randomly extracted from the prepared comparison test sample in S2, N is greater than or equal to 5, the water content and the density are measured respectively, then every two days detection is carried out, a total of M times, M is greater than or equal to 5, the consistency test method of average value is used for testing, the water content and the density of crude oil are detected, and the detection results are recorded, when the data values of the detection results are less than the T values obtained by looking up the table, then the stability of the comparison test sample prepared in S2 is qualified.

[0027] The formula of the consistency test method of average value in the stability test in the comparison test sample test S3 is as follows:

[0028]

[0029] Wherein: Average value of each test; S i Standard deviation of each test; n - number of tests of each group.

[0030] The water content and the density of crude oil in the uniformity test and the stability test in S3 are detected by GB / T 8929-2006 "Crude Oil Water Content Determination Method Distillation Method" and GB / T1884-2000 "Crude Oil and Liquid Petroleum Product Density Laboratory Determination Method (Densimeter Method)", respectively.

[0031] A crude oil standard sample preparation device, comprising: a stirring cylinder, a stirrer and a motor, the upper part of the stirring cylinder is provided with a sealing cover, the sealing cover is fixedly provided with a support, the motor is fixedly connected to the support, the lower part of the motor is connected with the stirrer, and the stirrer is located in the stirring cylinder.

[0032] The technical effect of the present application is that: 1. The crude oil standard sample preparation method provided by the present application fully considers the stability and uniformity of the crude oil sample, can be used as a crude oil standard sample to carry out interlaboratory comparison of crude oil testing, improve the analysis and testing level of the crude oil testing laboratory, and evaluate and assess the testing ability of the laboratory; 2. The present application solves the problem that the detection ability of the oilfield crude oil detection laboratory, including water content, density and analysis and testing level, is uneven, improves the accuracy and reliability of the crude oil transfer detection data, and reduces the loss of crude oil.

[0033] Further illustration will be made below in combination with the drawings. BRIEF DESCRIPTION OF DRAWINGS

[0034] Figure 1 It is a structure schematic diagram of a crude oil standard sample preparation device according to an embodiment of the present application.

[0035] The drawing label: 1 - stirring cylinder; 2 - stirrer; 3 - support; 4 - motor; 5 - sealing cover. DETAILED DESCRIPTION

[0036] Embodiment 1

[0037] In order to overcome the problem that there is no standard substance of crude oil density and water content at present due to the complexity of existing crude oil properties and the particularity of detection method, so that the comparison work of crude oil detection including water content and density between oilfield laboratories cannot be carried out, the purpose of the present application is to provide a crude oil standard sample preparation method and device, which fully considers the stability and uniformity of the crude oil sample, can carry out comparison work between crude oil testing laboratories as a crude oil standard sample, improve the analysis and test level of the crude oil testing laboratory, examine and evaluate the testing capacity of the laboratory, and improve the accuracy and reliability of the handover detection data of the crude oil.

[0038] The technical scheme of the present application is that: a crude oil standard sample preparation method comprises the following steps:

[0039] S1: sampling of comparison test samples;

[0040] The crude oil with density and water content values in the range of the density and water content of the crude oil detected daily by the laboratory participating in the comparison test in the oilfield is selected as the density and water content comparison test sample;

[0041] S2: preparation of comparison test samples;

[0042] The comparison test samples obtained in S1 are heated, stirred, and placed, and then are divided and packaged in containers as to-be-tested comparison test samples, which are sealed and stored;

[0043] S3: testing of comparison test samples;

[0044] The to-be-tested comparison test samples prepared in S2 are respectively subjected to uniformity test and stability test;

[0045] S4: if the uniformity test and stability test in S3 are all qualified, the comparison test samples prepared in S2 are regarded as crude oil standard samples.

[0046] In the sampling of comparison test samples, the water content of the crude oil selected in the oilfield is emulsified water, the water content is less than 0.2% in mass fraction, the color of the crude oil is uniform, and it is the crude oil after the crude oil stabilizing device.

[0047] S1: In the sampling of the comparison test sample, 120 L of crude oil is selected in the oil field as the density and water content comparison test sample; in the S2: comparison test sample preparation, the comparison test sample is divided into 1000 mL containers, a total of 100 bottles are divided, numbered from 001 to 100, and stored at room temperature.

[0048] In the S2: comparison test sample preparation, the heating temperature of the crude oil is between 30-40℃, stirring for 1 hour, and standing for 1 minute.

[0049] In the S3: uniformity test, N samples are randomly selected from the prepared comparison test samples in S2, N≥5, and the sample number is recorded; the variance analysis method is used to test the uniformity of the samples, the water content and density of the crude oil are detected, and the detection results are recorded; when the F value of the detection result data is less than the F value obtained by looking up the table, the uniformity of the comparison test sample prepared in S2 is qualified.

[0050] The formula of the variance analysis method in the S3: uniformity test is as follows:

[0051]

[0052]

[0053]

[0054]

[0055] v1=m-1 (5)

[0056] v2=N-m (6)

[0057]

[0058] Wherein: Total mean; Q1- between-group sum of squares; Q2- within-group sum of squares; m- sample number; n- single sample repeated test number.

[0059] In the S3: stability test, N samples are randomly selected from the prepared comparison test samples in S2, N≥5, and the water content and density are measured, respectively, and then every two days, a total of M times, M≥5, are detected, and the average value consistency test method is used for testing, the water content and density of the crude oil are detected, and the detection results are recorded; when the T value of the detection result data is less than the T value obtained by looking up the table, the stability of the comparison test sample prepared in S2 is qualified.

[0060] The S3: the average value of the stability test in the comparison test sample inspection consistency test method formula as follows:

[0061]

[0062] Wherein: The average value of each test; S i The standard deviation of each test; n - the number of tests in each group.

[0063] The S3 homogeneity test and stability test of crude oil water content, density detection, respectively, by GB / T 8929-2006 "determination of water content in crude oil distillation method" and GB / T1884-2000 "crude oil and liquid petroleum products density laboratory determination method (densimeter method)" detection.

[0064] Example 2

[0065] A kind of crude oil standard sample preparation device, as shown in Figure 1 The upper portion of the stirring cylinder 1 is provided with a sealing cover 5, the sealing cover 5 is fixedly provided with a support 3, the motor 4 is fixedly connected to the support 3, the motor 4 is connected with the stirrer 2 at the lower portion, and the stirrer 2 is located in the stirring cylinder 1.

[0066] In actual use, the container containing the comparison test sample is heated to have sufficient fluidity, the crude oil in the container is poured into the stirring cylinder 1, the stirrer 2 is driven by the motor 4 to stir the crude oil in the stirring cylinder 1 for 1 hour, and then the stirring cylinder 1 is placed for 1 minute. The stirring effect is that the crude oil containing emulsified water is uniformly mixed, and the standing effect is that the rotated crude oil after stirring stops before the oil-in-water appears.

[0067] Example 3

[0068] The crude oil standard sample is prepared in a certain oil field, and the whole process is as follows:

[0069] S1: comparison test sample sampling;

[0070] The crude oil with density and water content values in the range of the density and water content of the crude oil detected by the laboratory participating in the comparison test on a daily basis is selected as the density and water content comparison test sample, and 120L of crude oil is taken by a 125L container. The selected crude oil has a water content of less than 0.2% by mass fraction, and the selected crude oil is uniform in color, which is the crude oil after the crude oil stabilizing device;

[0071] S2: comparison test sample preparation;

[0072] The comparison test sample crude oil obtained in S1 is heated to a temperature of 30-40°C, and has sufficient flowability. The sample is prepared using a crude oil standard sample preparation device as shown in Figure 1 , stirred for 1 hour, allowed to stand for 1 minute, and then the sample is divided into 1000 mL jars, sealed with a cap, and each sample is divided into 100 jars numbered from 001 to 100, and stored at room temperature.

[0073] S3: Test of the comparison test sample;

[0074] Uniformity test; the specific process is as follows:

[0075] Five samples are randomly selected from the samples prepared in S2, and the sample numbers are recorded. The samples are tested for uniformity using the variance analysis method, and the water content and density are tested using GB / T 8929-2006 "Determination of water content in crude oil - Distillation method" and GB / T 1884-2000 "Determination of density of crude petroleum and liquid petroleum products - Laboratory method (hydrometer method)", respectively. The test results are recorded as shown in Tables 1 and 2.

[0076] Table 1: Density uniformity test record (g / cm 3 )

[0077]

[0078] The formula for the variance analysis method for uniformity test in the comparison test sample test is as follows:

[0079]

[0080]

[0081]

[0082]

[0083] v1 = m-1 (5)

[0084] v2 = N-m (6)

[0085]

[0086] Wherein: —total average; Q1—between-group sum of squares; Q2—intra-group sum of squares; m—number of samples taken; n—number of repeated tests for a single sample.

[0087] F = 2.06 is calculated.

[0088] Table 2: Water content uniformity test record (%)

[0089]

[0090] Similarly, F = 5.05 is calculated.

[0091] Referring to Table 3, the total average value of five samples in the standard table of variance analysis method is F0.05(4,5) = 5.19, and the result of variance analysis method of the data value of the test result is less than 5.19, so the uniformity of the prepared comparison test sample in S2 is qualified.

[0092] Table 3 F value table of variance analysis method

[0093] P = 0.05

[0094] r1 (degree of freedom of larger mean square)

[0095] r2 1 2 3 4 5 6 7 8 9 10 12 14 16 18 20 r2 1 161 200 216 225 230 234 237 239 241 242 244 245 246 247 248 1 2 18.5 19.0 19.2 19.2 19.3 19.3 19.4 19.4 19.4 19.4 19.4 19.4 19.4 19.4 19.4 2 3 10.1 9.55 9.28 9.12 9.01 8.94 8.89 8.85 8.81 8.79 8.74 8.71 8.69 8.67 8.66 3 4 7.71 6.94 6.59 6.39 6.26 6.16 6.09 6.04 6.00 5.96 5.91 5.87 5.84 5.82 5.80 4 5 6.61 5.79 5.41 5.19 5.05 4.95 4.88 4.82 4.77 4.74 4.68 4.64 4.60 4.58 4.56 5 6 5.99 5.14 4.76 4.53 4.39 4.28 4.21 4.15 4.10 4.06 4.00 3.96 3.92 3.90 3.87 6 7 5.59 4.74 4.35 4.12 3.97 3.87 3.79 3.73 3.68 3.64 3.57 3.53 3.49 3.47 3.44 7 8 5.32 4.46 4.07 3.84 3.69 3.58 3.50 3.44 3.39 3.35 3.28 3.24 3.20 3.17 3.15 8 9 5.12 4.26 3.86 3.63 3.48 3.37 3.29 3.23 3.18 3.14 3.07 3.03 2.99 2.96 2.94 9 10 4.96 4.10 3.71 3.48 3.33 3.22 3.14 3.07 3.02 2.98 2.91 2.86 2.83 2.80 2.77 10 11 4.84 3.98 3.59 3.36 3.20 3.09 3.01 2.95 2.90 2.85 2.79 2.74 2.70 2.67 2.65 11 12 4.75 3.89 3.49 3.26 3.11 3.00 2.91 2.85 2.80 2.75 2.69 2.64 2.60 2.57 2.54 12 13 4.67 3.81 3.41 3.18 3.03 2.92 2.83 2.77 2.71 2.67 2.60 2.55 2.51 2.48 2.46 13 14 4.60 3.74 3.34 3.11 2.96 2.85 2.76 2.70 2.65 2.60 2.53 2.48 2.44 2.41 2.39 14 15 4.54 3.68 3.29 3.06 2.90 2.79 2.71 2.64 2.59 2.54 2.48 2.42 2.38 2.35 2.33 15 16 4.49 3.63 3.24 3.01 2.85 2.74 2.66 2.59 2.54 2.49 2.42 2.37 2.33 2.30 2.28 16 17 4.45 3.59 3.20 2.96 2.81 2.70 2.61 2.55 2.49 2.45 2.38 2.33 2.29 2.26 2.23 17 18 4.41 3.55 3.16 2.93 2.77 2.66 2.58 2.51 2.46 2.41 2.34 2.29 2.25 2.22 2.19 18 19 4.38 3.52 3.13 2.90 2.74 2.63 2.54 2.48 2.42 2.38 2.31 2.26 2.21 2.18 2.16 19 20 4.35 3.49 3.10 2.87 2.71 2.60 2.51 2.45 2.39 2.35 2.28 2.22 2.18 2.15 2.12 20 21 4.32 3.47 3.07 2.84 2.68 2.57 2.49 2.42 2.37 2.32 2.25 2.20 2.16 2.12 2.10 21 22 4.30 3.44 3.05 2.82 2.66 2.55 2.46 2.40 2.34 2.30 2.23 2.17 2.13 2.10 2.07 22 23 4.28 3.42 3.03 2.80 2.64 2.53 2.44 2.37 2.32 2.27 2.20 2.15 2.11 2.07 2.05 23 24 4.26 3.40 3.01 2.78 2.62 2.51 2.42 2.36 2.30 2.25 2.18 2.13 2.09 2.05 2.03 24 25 4.24 3.39 2.99 2.76 2.60 2.49 2.40 2.34 2.28 2.24 2.16 2.11 2.07 2.04 2.01 25 26 4.23 3.37 2.98 2.74 2.59 2.47 2.39 2.32 2.27 2.22 2.15 2.09 2.05 2.02 1.99 26 27 4.21 3.35 2.96 2.73 2.57 2.46 2.37 2.31 2.25 2.20 2.13 2.08 2.04 2.00 1.97 27 28 4.20 3.34 2.95 2.71 2.56 2.45 2.36 2.29 2.24 2.19 2.12 2.06 2.02 1.99 1.96 28 29 4.18 3.33 2.93 2.70 2.55 2.43 2.35 2.28 2.22 2.18 2.10 2.05 2.01 1.97 1.94 29 30 4.17 3.32 2.92 2.69 2.53 2.42 2.33 2.27 2.21 2.16 2.09 2.04 1.99 1.96 1.93 30 32 4.15 3.29 2.90 2.67 2.51 2.40 2.31 2.24 2.19 2.14 2.07 2.01 1.97 1.94 1.91 32 34 4.13 3.28 2.88 2.65 2.49 2.38 2.29 2.23 2.17 2.12 2.05 1.99 1.95 1.92 1.89 34 36 4.11 3.26 2.87 2.63 2.48 2.36 2.28 2.21 2.15 2.11 2.03 1.98 1.93 1.90 1.87 36

[0096] Stability test; the specific process is as follows:

[0097] Five samples are randomly selected from the samples prepared in S2, and the water content and density are measured, and then the test is performed every two days for a total of five times, and the uniformity test method of average value is used for testing, wherein the water content and density are tested by GB / T 8929-2006 "Determination of Water Content in Crude Oil-Distillation Method" and GB / T 1884-2000 "Laboratory Determination of Density of Crude Oil and Liquid Petroleum Products (Densimeter)", and the test results are recorded, as shown in Tables 4 and 5.

[0098] Table 4 Density stability test record (g / cm 3 )

[0099] No. One Two Three Four Five X average S square T value 1 863.1 863.05 863.3 862.9 863.0 863.07 0.0220 2 862.95 863.15 863.05 863.25 865.1 863.5 0.8125 1.05 3 863.3 863.5 865.0 862.35 862.65 863.36 1.0593 0.62 4 863.1 863.4 863.4 863.9 863.4 863.44 0.0830 2.55 5 865.8 862.8 864.1 863.0 863.6 863.86 1.4380 1.46

[0100] Table 5 Water content stability test record (%)

[0101] No. One Two Three Four Five X average S square T value 1 0.344 0.322 0.400 0.3455 0.3715 0.3566 0.0009 2 0.403 0.401 0.336 0.351 0.4035 0.3789 0.0011 1.12 3 0.3345 0.3558 0.395 0.363 0.320 0.35366 0.0008 0.16 4 0.376 0.378 0.438 0.371 0.372 0.387 0.0008 1.64 5 0.451 0.393 0.374 0.377 0.397 0.3984 0.0010 2.17

[0102] Referring to Table 6 T test critical value table, the average value of each test of 5 samples in the standard table of uniformity test method of average value is T0.05(4) = 2.78, and when the result of the uniformity test method of average value of the data value of the test result is less than 2.78, the stability of the prepared comparison test sample in S2 is qualified.

[0103] Table 6 T test critical value table

[0104]

[0105] S4: If the uniformity test and stability test in S3 are all qualified, the comparison test sample prepared in S2 is used as the crude oil standard sample.

[0106] The above merely describes preferred specific embodiments of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art can easily think of changes or replacements within the technical scope disclosed by the present application, which should be covered within the protection scope of the present application.

Claims

1. A method for preparing a crude oil standard sample, characterized by: The utility model discloses a crude oil standard sample preparation device, which comprises a stirring cylinder (1), a stirrer (2) and a motor (4), the upper portion of the stirring cylinder (1) is provided with a sealing cover (5), the sealing cover (5) is fixedly provided with a support (3), the motor (4) is fixedly connected to the support (3), the lower portion of the motor (4) is connected with the stirrer (2), and the stirrer (2) is located in the stirring cylinder (1). S1: comparing test sample sampling; In the oil field, select the crude oil with density and water content values in the range of the density and water content of the crude oil detected by the laboratory participating in the comparison test as the density and water content comparison test sample; S2: comparison test sample preparation; The comparison test sample obtained in S1 is heated, stirred and placed, and then is divided and stored in containers as the detected comparison test sample, and is sealed and stored; S3: comparison test sample inspection; The detected comparison test sample prepared in S2 is subjected to uniformity inspection and stability inspection, the specific process of the uniformity inspection is that N samples are randomly taken from the detected comparison test sample prepared in S2, N is greater than or equal to 5, and the sample number is recorded; the samples are subjected to uniformity inspection by using the variance analysis method, the water content and density of the crude oil are detected, and the detection results are recorded; when the F values of the detection result data values are all less than the F values obtained by looking up the table, the uniformity of the comparison test sample prepared in S2 is qualified, the specific process of the stability inspection is that N samples are randomly taken from the detected comparison test sample prepared in S2, N is greater than or equal to 5, the water content and density are respectively detected, the detection is performed every two days, the detection is performed M times, M is greater than or equal to 5, the detected comparison test sample is subjected to inspection by using the average value consistency inspection method, the water content and density of the crude oil are detected, and the detection results are recorded; when the T values of the detection result data values are all less than the T values obtained by looking up the table, the stability of the comparison test sample prepared in S2 is qualified; In the uniformity inspection and stability inspection in S3, the water content and density of the crude oil are detected by using GB / T 8929-2006 "determination of water content in crude oil - distillation method" and GB / T1884-2000 "laboratory determination of density of crude oil and liquid petroleum products (densitometer method)"; S4: if the uniformity inspection and stability test in S3 are all qualified, the comparison test sample prepared in S2 is used as the crude oil standard sample.

2. The method for preparing a crude oil standard sample according to claim 1, characterized in that: In the comparison test sample sampling in S1, the water content of the crude oil selected in the oil field is emulsified water, the water content is less than 0.2% in mass fraction, and the color of the crude oil is uniform, which is the crude oil after the crude oil stabilizing device.

3. The method for preparing a crude oil standard sample according to claim 1, characterized in that: In the comparison test sample sampling in S1, 120L of the crude oil is selected as the density and water content comparison test sample; in the comparison test sample preparation in S2, the comparison test sample is divided and stored in 1000ml containers, a total of 100 bottles are numbered from 001 to 100, and are stored at room temperature.

4. The method of claim 1, wherein: S2: In the preparation of the test sample, the crude oil is heated to a temperature of 30-40°C, stirred for 1 hour, and left to stand for 1 minute.

5. The method of claim 1, wherein: The formula for the variance analysis method of the homogeneity test in S3 is as follows: （1） （2） （3） （4） （5） （6） （7） Where: — Total mean; — Between groups sum of squares; — Within groups sum of squares; — Number of samples taken; — Number of individual sample replicates.

6. The method of claim 1, wherein: S3: The formula for the consistency test of the average value of the stability test in the test of the test sample is as follows: （8） wherein: - the average value of each set of tests; - the standard deviation of each set of tests; - the number of tests of each set.

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