Method for obtaining target crude oil mixing formula

Abstract

The invention relates to a method for obtaining a mixed formula of target crude oil, which comprises the following steps: respectively carrying out spectrogram pretreatment on near infrared spectrums of known crude oil samples and crude oil samples to be detected in an established crude oil sample database, and utilizing a library fitting algorithm to obtain the mixed formula of the target crude oil of which the properties meet requirements. The blending scheme is simple and easy to obtain, the obtained formula is high in accuracy, and the application range is wide.

Description

Technical Field

[0001] The present disclosure relates to a method for obtaining a target crude oil blending formulation. Background Art

[0002] Crude oil blending refers to the process of mixing multiple crude oils in a certain proportion to obtain a blended crude oil with the desired crude oil properties. In the case of many types of crude oils with different properties, crude oil blending can be used to mix different crude oils into a specific crude oil. Modern spectral techniques (such as nuclear magnetic resonance, infrared, Raman and nuclear magnetic resonance, etc.) have the characteristics of fast speed, simultaneous measurement of multiple properties and suitability for online non-destructive analysis. At present, they have been increasingly applied to petrochemical, agricultural and pharmaceutical fields, especially playing a positive and irreplaceable role in process analysis.

[0003] CN102374975A ​​proposes a library spectrum fitting method, which is based on the near-infrared spectrum library of oil products and spectrum fitting technology. Its basic principle is that the properties of samples with similar spectra are also similar. The spectrum of the unknown sample to be tested is fitted through one or more spectra in the spectrum library, and then the properties of the sample to be tested are calculated based on the properties of the oil products involved in the fitted spectrum. The chemical essence of this method is that the unknown sample can be mixed by a group of library samples in a certain proportion. Therefore, the properties of the unknown sample to be tested can be calculated according to the mixing proportion through the properties of the library samples.

[0004] CN102643662A discloses a crude oil blending optimization method, which supports the minimum deviation between the property content of the blended crude oil and the target, that is, under certain constraints, the deviation function between the relevant property content of each blended crude oil and the set target is minimized to obtain the proportion of various blended crude oils. However, this method can only optimize the properties of a limited number of canned crude oils. Summary of the invention

[0005] The purpose of the present disclosure is to provide a method for obtaining a target crude oil mixed formula, which can quickly and accurately obtain a mixed formula containing crude oil with specified components according to actual production needs.

[0006] In order to achieve the above object, the present disclosure provides a method for obtaining a target crude oil blending formula, the method comprising the following steps:

[0007] Acquire a near-infrared spectrum database containing a plurality of known crude oil samples; wherein the near-infrared spectrum database includes a library spectrum obtained by spectral preprocessing of the near-infrared spectrum of each of the known crude oil samples and standard data of key physical properties of each of the known crude oil samples, and the library spectra of the plurality of known crude oil samples constitute a first spectrum matrix;

[0008] Acquire a near infrared spectrum of a target crude oil sample and perform the spectrum preprocessing on the near infrared spectrum of the target crude oil sample to obtain a second spectrum; wherein the target crude oil sample is obtained by mixing a plurality of component crude oils, and the component crude oils include a specified component crude oil and an undetermined component crude oil;

[0009] The spectrum to be fitted is calculated according to the following formula (1):

[0010]

[0011] Where C is the spectrum to be fitted, B is the second spectrum, A i is the library spectrum of the i-th specified component crude oil, j i For the specified component crude oil A i The mixing ratio of n is the number of types of crude oil of the specified component;

[0012] Fitting the spectrum to be fitted by using the first spectrum matrix to obtain fitting coefficients of the crude oil with undetermined components;

[0013] Determining the mixing ratio of the crude oil of undetermined components according to the fitting coefficient;

[0014] The mixing ratio of the undetermined component crude oil and the mixing ratio of the specified component crude oil are normalized to obtain a mixing formula of the target crude oil sample.

[0015] Optionally, the spectrum preprocessing includes:

[0016] The absorbance of the characteristic spectral region of the near infrared spectrum is subjected to first-order differential processing and normalized according to the following formula (2):

[0017]

[0018] Among them, x nor is the absorbance vector of the normalized spectrum, x 0 is the absorbance vector of the original spectrum, is the average spectral vector and is calculated according to the following formula (3), m is the number of wavelength points for collecting spectral absorbance, k is the sampling point number for collecting spectral absorbance, k = 1, 2, ..., m,

[0019]

[0020] Optionally, the characteristic spectrum range is 4000-4700 cm -1 and 5300~6000cm -1 .

[0021] Optionally, the method comprises:

[0022] Using a non-negative constrained least square method to determine non-zero fitting coefficients in the fitting coefficients, and normalizing the non-zero fitting coefficients to obtain normalized fitting coefficients;

[0023] The mixing ratio of the crude oil with undetermined components is determined according to the normalized fitting coefficient.

[0024] Optionally, the method comprises:

[0025] The fitting is performed according to the following formula (4):

[0026]

[0027] Wherein, p is the spectrum to be fitted, v i is the library spectrum involved in the fitting, t is the number of library spectra involved in the fitting, a i is the fitting coefficient corresponding to the ith library spectrum and satisfies the objective function shown in the following formula (5):

[0028]

[0029] The non-zero fitting coefficients among all the obtained fitting coefficients are extracted and normalized according to the following formula (6):

[0030]

[0031] Among them, b i is the normalized fitting coefficient of the i-th crude oil with unknown components, and g is the number of library spectra corresponding to non-zero fitting coefficients.

[0032] Optionally, the method comprises:

[0033] The mixing ratio of the undetermined crude oil is calculated according to the following formula (7):

[0034]

[0035] Among them, m i is the mixing ratio of the i-th crude oil with uncertain components, b i is the normalized fitting coefficient of the i-th crude oil with uncertain components, j i For the specified component crude oil A i The mixing ratio of n is the number of types of crude oil of the specified component.

[0036] Optionally, the key physical properties include at least one of density, acid value, carbon residue value, sulfur content, nitrogen content, wax content, resin content and asphaltene content.

[0037] Optionally, the density is tested according to standard method SH / T 0604-2000;

[0038] The acid value is tested according to the standard method GB / T 7304-2014;

[0039] The carbon residue value is tested according to the standard method GB / T 17144;

[0040] The sulfur content is tested according to the standard method GB / T17040-2008;

[0041] The nitrogen content is tested according to the standard method GB / T 17674;

[0042] The wax content is tested according to standard method SY / T 0537;

[0043] The colloid content is tested according to the standard method SY / T 7550;

[0044] The asphaltene content is measured according to the standard method SY / T 7550.

[0045] Optionally, the near-infrared spectrum is acquired using a Fourier transform near-infrared spectrometer.

[0046] Optionally, the near infrared spectroscopy detection conditions of the known crude oil sample and the target crude oil sample independently include: a resolution of 2 to 16 cm -1 , the wave number range is 4000~10000cm -1 , scan times 64 times.

[0047] Through the above technical scheme, the present invention performs spectral preprocessing on the near-infrared spectra of known crude oil samples in the established crude oil sample database and the crude oil samples to be tested, and uses the library fitting algorithm to obtain a mixed formula of the target crude oil with properties that meet the requirements. This method is particularly suitable for situations in actual work where it is necessary to specify certain library crude oils to participate in the formula in proportion. The blending scheme is simple and easy to obtain, the obtained formula is highly accurate, and has a wide range of applications.

[0048] Other features and advantages of the present disclosure will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] The accompanying drawings are used to provide a further understanding of the present disclosure and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the present disclosure but do not constitute a limitation of the present disclosure. In the accompanying drawings:

[0050] Figure 1 It is a schematic flow chart of a method for obtaining a target crude oil blending formula provided in one embodiment of the present disclosure. DETAILED DESCRIPTION

[0051] The specific implementation of the present disclosure is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described herein is only used to illustrate and explain the present disclosure, and is not used to limit the present disclosure.

[0052] The present disclosure provides a method for obtaining a target crude oil blending formula, such as Figure 1 As shown, the method includes the following steps S101 to S106:

[0053] S101, obtaining a near-infrared spectrum database containing a plurality of known crude oil samples; wherein the near-infrared spectrum database includes a library spectrum obtained by performing spectral preprocessing on the near-infrared spectrum of each of the known crude oil samples and standard data of key physical properties of each of the known crude oil samples, and the library spectra of the plurality of known crude oil samples constitute a first spectrum matrix;

[0054] S102, obtaining a near infrared spectrum of a target crude oil sample and performing the spectrum preprocessing on the near infrared spectrum of the target crude oil sample to obtain a second spectrum; wherein the target crude oil sample is obtained by mixing a plurality of component crude oils, and the component crude oils include a specified component crude oil and an undetermined component crude oil;

[0055] S103, calculating the spectrum to be fitted according to the following formula (1):

[0056]

[0057] Where C is the spectrum to be fitted, B is the second spectrum, A i is the library spectrum of the i-th specified component crude oil, j i For the specified component crude oil A i The mixing ratio of n is the number of types of crude oil of the specified component;

[0058] S104, fitting the spectrum to be fitted by using the first spectrum matrix to obtain the fitting coefficient of the crude oil with undetermined components;

[0059] S105, determining the mixing ratio of the crude oil with undetermined components according to the fitting coefficient;

[0060] S106: normalize the mixing ratio of the undetermined component crude oil and the mixing ratio of the designated component crude oil to obtain a mixing formula of the target crude oil sample.

[0061] The present invention pre-processes the near infrared spectra of known crude oil samples and crude oil samples to be tested in the established crude oil sample database, and uses the library fitting algorithm to obtain a mixed formula of target crude oil with properties that meet the requirements. It is particularly suitable for situations where it is necessary to specify certain library crude oils to participate in the formula in proportion in actual work. The obtained formula has high accuracy and a wide range of applications. The blending scheme obtained by this method is simple and easy to obtain, does not require modeling of library samples, and the database maintenance is simple and convenient, which has good application prospects.

[0062] In step S101, the known crude oil sample refers to a crude oil sample with known composition and / or properties, which can be a crude oil sample in a crude oil database established on a near-infrared spectrometer or an actual crude oil sample collected from major production areas around the world. The number of the known crude oil samples can preferably be 100 to 200 to further improve the accuracy of the obtained mixed formula.

[0063] The standard data of key physical properties refers to the standard data obtained by testing the key physical properties of the known crude oil sample using standard methods. The key physical properties involved may include but are not limited to density, acid value, residual carbon value, sulfur content, nitrogen content, wax content, colloid content, asphaltene content, actual boiling point distillation data, etc., and the appropriate type and quantity of physical properties can be selected according to needs. Each physical property is measured using standard methods. Specifically, the density can be detected according to the standard method SH / T 0604-2000 Density determination of crude oil and petroleum products (U-shaped vibrating tube method); the acid value can be detected according to the standard method GB / T 7304-2014 Determination of acid value of petroleum products-potentiometric titration method; the sulfur content can be detected according to the standard method GB / T17040-2008 Energy dispersive X-ray determination of sulfur content in petroleum and petroleum products; the carbon residue value can be detected according to the standard method GB / T 17144 Determination of carbon residue in petroleum products; the nitrogen content can be detected according to the standard method GB / T 17674 Determination of nitrogen content in crude oil; the wax content can be detected according to the standard method SY / T 0537 Determination of wax content in crude oil; the colloid and asphaltene content can be detected according to the standard method SY / T 7550 Determination of wax, colloid and asphaltene content in crude oil; the actual boiling point distillation data can be detected according to the standard method GB / T 17280 Standard test method for crude oil distillation.

[0064] In step S102, the target crude oil sample can be obtained by blending the known crude oil samples in the near infrared spectrum database. In the actual production process of the refinery, crude oil blending is often not performed according to the optimal formula in the library spectrum, but certain crude oils are usually specified to participate in the blending in a certain proportion. The disclosed scheme is particularly suitable for this situation, and some component crude oils in the obtained mixed formula can be pre-specified according to actual production needs. That is, the target crude oil sample is obtained by mixing multiple component crude oils (i.e., the known crude oils in the library spectrum), and the obtained mixed formula is the type of each component crude oil and its corresponding mixing ratio. The component crude oils include specified component crude oils and undetermined component crude oils, wherein the specified component crude oil refers to a component crude oil of known type and its mixing ratio, and the undetermined component crude oil refers to a component crude oil of a to-be-determined type and its mixing ratio. The specified component crude oil can be one or more, and the mixing ratio of each of the specified component crude oils can be adjusted over a wide range.

[0065] In steps S101 and S102, various near-infrared spectroscopy detection devices commonly used in the art can be used to obtain the near-infrared spectrum. In a specific embodiment, a Fourier transform near-infrared spectrometer is used to obtain the near-infrared spectrum. The conditions for detecting samples using a Fourier transform near-infrared spectrometer may be well known to those skilled in the art. The detection of the known crude oil sample and the detection of the target crude oil sample are preferably carried out under the same detection conditions to improve the accuracy of the obtained mixed formula. Specifically, the detection can be a transmission detection, using a cuvette injection method, and the transmission light path is 0.5mm; the detection conditions may include: a resolution of 2 to 16cm -1 , the wave number range is 4000~10000cm -1 , scan times 64 times.

[0066] The near infrared spectrum of the known crude oil sample and the near infrared spectrum of the target crude oil sample each need to be subjected to spectral preprocessing before subsequent fitting, and the spectral preprocessing performed on the near infrared spectrum of the known crude oil sample and the spectral preprocessing performed on the near infrared spectrum of the target crude oil sample are preferably the same spectral preprocessing process. For example, the spectral preprocessing may each include, but is not limited to, differential processing, standardization processing, normalization processing, and wavelet transform processing.

[0067] In a specific embodiment, the spectrum preprocessing includes:

[0068] The absorbance of the characteristic spectral region of the near infrared spectrum is subjected to first-order differential processing and normalized according to the following formula (2):

[0069]

[0070] Among them, xnor is the absorbance vector of the normalized spectrum, x 0 is the absorbance vector of the original spectrum, is the average spectral vector and is calculated according to the following formula (3), m is the number of wavelength points for collecting spectral absorbance, k is the sampling point number for collecting spectral absorbance, k = 1, 2, ..., m,

[0071]

[0072] The first-order differential processing method is well known to computer personnel in the field. The characteristic spectrum range is 4000-4700 cm -1 and 5300~6000cm -1 The sampling point interval of the characteristic spectrum area can be 2 to 16 wave numbers. By selecting an appropriate characteristic spectrum area range, it is helpful to further improve the accuracy of the evaluation results.

[0073] In step S103, since the mixed formula includes the specified component crude oil, the library spectrum of the specified component crude oil is removed from formula (1) to obtain the spectrum to be fitted, which is used for subsequent fitting to improve the accuracy of the obtained mixed formula.

[0074] In step S104, the library spectrum involved in the fitting and its fitting coefficient can be obtained by fitting, wherein the library spectrum involved in the fitting includes the library spectrum of the crude oil of indeterminate composition. The fitting coefficient is preferably a non-zero fitting coefficient after normalization, for example, the fitting coefficient is determined according to the non-negative constrained least squares method.

[0075] In one embodiment, the method includes: using a non-negative constrained least squares method to determine a non-zero fitting coefficient in the fitting coefficient, and normalizing the non-zero fitting coefficient to obtain a normalized fitting coefficient; and determining the mixing ratio of the undetermined component crude oil according to the normalized fitting coefficient.

[0076] For example, the fitting is performed according to the following formula (4):

[0077]

[0078] Wherein, p is the spectrum to be fitted, v i is the library spectrum involved in the fitting, t is the number of library spectra involved in the fitting, a i is the fitting coefficient corresponding to the ith library spectrum and satisfies the objective function shown in the following formula (5):

[0079]

[0080] The non-zero fitting coefficients among all the obtained fitting coefficients are extracted and normalized according to the following formula (6):

[0081]

[0082] In formula (5), b i is the normalized fitting coefficient of the i-th crude oil with unknown components, and g is the number of library spectra corresponding to non-zero fitting coefficients.

[0083] In step S105, the mixing ratio of the crude oil with undetermined components is calculated according to the obtained fitting coefficient.

[0084] Specifically, the method includes:

[0085] The mixing ratio of the undetermined crude oil is calculated according to the following formula (7):

[0086]

[0087] Among them, m i is the mixing ratio of the i-th crude oil with uncertain components, b i is the normalized fitting coefficient of the i-th crude oil with uncertain components, j i For the specified component crude oil A i The mixing ratio of n is the number of types of crude oil of the specified component.

[0088] In step S106, the mixing ratio of the crude oil with undetermined components and the mixing ratio of the crude oil with specified components are normalized by using a normalization method conventional in the art, so as to obtain the mixing formula of the target crude oil sample.

[0089] The disclosed method can be used to obtain mixed formulas of various target crude oil samples and has wide applicability.

[0090] The present disclosure is further illustrated below by examples, but the present disclosure is not limited thereto.

[0091] The instrument used to collect the near-infrared spectrum of crude oil in this example is a Fourier transform near-infrared spectrometer produced by Thermo, model Antaris II, and the spectrum collection conditions are: resolution 8cm -1 , wave number range 4000~10000cm -1 , cumulative scanning times 64 times, transmission measurement method.

[0092] Density is tested according to standard method SH / T 0604-2000 Density determination of crude oil and petroleum products (U-shaped vibrating tube method); acid value is tested according to standard method GB / T 7304-2014 Determination of acid value of petroleum products - potentiometric titration; sulfur content is tested according to standard method GB / T17040-2008 Energy dispersive X-ray determination of sulfur content of petroleum and petroleum products; carbon residue value is tested according to standard method GB / T17144 Determination of carbon residue in petroleum products; nitrogen content is tested according to standard method GB / T 17674 Determination of nitrogen content in crude oil; wax content is tested according to standard method SY / T 0537 Determination of wax content in crude oil; colloid and asphaltene content are tested according to standard method SY / T 7550 Determination of wax, colloid and asphaltene content in crude oil; true boiling point distillation data is tested according to standard method GB / T 17280 Standard test method for crude oil distillation.

[0093] Example 1

[0094] (I) Construction of a near-infrared spectral database of known crude oil samples

[0095] 210 kinds of crude oil samples from major producing areas around the world were collected, covering the major crude oil producing areas in the world. A known crude oil sample library was formed. Standard data such as crude oil density, acid value, sulfur content, etc. were determined using standard methods, and the near-infrared spectra of crude oil samples were determined. The 4000-4700cm near-infrared spectra of known crude oil samples were -1 and 5300~6000cm -1 The absorbance of the characteristic spectral region is subjected to first-order differential processing and normalized according to the following formula (2):

[0096]

[0097] Among them, x nor is the absorbance vector of the normalized spectrum, x 0 is the absorbance vector of the original spectrum, is the average spectral vector and is calculated according to the following formula (3), m is the number of wavelength points for collecting spectral absorbance, k is the sampling point number for collecting spectral absorbance, k = 1, 2, ..., m,

[0098]

[0099] The number of wavenumber sampling points in the characteristic spectrum region is 365, and the library spectrum obtained after processing constitutes the first spectrum matrix.

[0100] (ii) collecting the near infrared spectrum of the target crude oil sample and its corresponding physical property data under the same detection conditions, and obtaining a second spectrum according to the same spectrum preprocessing method as in step (i).

[0101] In the mixing formula of the target crude oil sample, the mixing ratio j of the designated component crude oil A is 60 wt %.

[0102] The spectrum to be fitted is calculated according to the following formula (1):

[0103]

[0104] Where C is the spectrum to be fitted, B is the second spectrum, A i is the i-th specified component crude oil, j i For the specified component crude oil A i The mixing ratio of n is the number of types of crude oil of the specified component;

[0105] (iii) Using the first spectrum matrix to fit the spectrum to be fitted according to the following formula (4):

[0106]

[0107] Wherein, p is the spectrum to be fitted, v i is the library spectrum involved in the fitting, t is the number of library spectra involved in the fitting, a i is the fitting coefficient corresponding to the ith library spectrum and satisfies the objective function shown in the following formula (5):

[0108]

[0109] The non-zero fitting coefficients among all the obtained fitting coefficients are extracted and normalized according to the following formula (6):

[0110]

[0111] Among them, b i is the normalized fitting coefficient of the i-th crude oil with unknown components, and g is the number of library spectra corresponding to non-zero fitting coefficients.

[0112] (iv) Calculate the mixing ratio of crude oil of uncertain composition according to the following formula (7):

[0113]

[0114] Among them, m i is the mixing ratio of the i-th crude oil with uncertain components, b i is the normalized fitting coefficient of the i-th crude oil with uncertain components, j i For the specified component crude oil A i The mixing ratio of n is the number of types of crude oil of the specified component.

[0115] The mixing ratio of the undetermined crude oil and the specified crude oil were normalized, and the resulting mixing formula was shown in Table 1. The blended crude oil was obtained according to the formula, and the comparison of the main physical properties of the target crude oil and the blended crude oil is shown in Table 2.

[0116] Table 1

[0117]

[0118]

[0119] Table 2

[0120] project Target crude oil Blended crude oil <![CDATA[Density, g·cm -3 > 0.8696 0.8718 Acid value, mg KOH / g 0.15 0.16 Carbon residue value, weight % 6.17 6.02 Sulfur content, weight % 2.40 2.65 Nitrogen content, weight % 0.12 0.12 Wax content, weight % 5.30 4.09 Gum content, weight % 9.90 8.84 Asphaltene content, weight % 2.80 2.26

[0121] Example 2

[0122] The mixed formula of the same target crude oil is obtained according to the method of Example 1, except that in step (ii), in the mixed formula of the target crude oil sample, there are two designated component crude oils, including: designated component crude oil A 1 The mixing ratio j 1 60% by weight of the designated component crude oil A 2 The mixing ratio j 2 It is 12% by weight.

[0123] The obtained mixing formula is shown in Table 3. According to the formula, the blended crude oil is obtained. The comparison of the main physical properties of the target crude oil and the blended crude oil is shown in Table 4.

[0124] Table 3

[0125] Serial number Crude oil number involved in the blending Mixing ratio 1 <![CDATA[A 1 ]]> 0.62 2 <![CDATA[A 2 ]]> 0.12 3 17 0.01 4 41 0.04 5 137 0.10 6 200 0.11

[0126] Table 4

[0127]

[0128]

[0129] It can be seen from the results of Examples 1 to 2 that the method disclosed herein can be used to quickly and accurately obtain a target crude oil mixed formula containing crude oil of specified components according to actual production needs.

[0130] The preferred embodiments of the present disclosure are described in detail above in conjunction with the accompanying drawings; however, the present disclosure is not limited to the specific details in the above embodiments. Within the technical concept of the present disclosure, a variety of simple modifications can be made to the technical solution of the present disclosure, and these simple modifications all fall within the protection scope of the present disclosure.

[0131] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present disclosure will not further describe various possible combinations.

[0132] In addition, various embodiments of the present disclosure may be arbitrarily combined, and as long as they do not violate the concept of the present disclosure, they should also be regarded as the contents disclosed by the present disclosure.

Claims

1. A method for obtaining a target crude oil blending formula, characterized in that: The method comprises the following steps: Acquire a near-infrared spectrum database containing a plurality of known crude oil samples; wherein the near-infrared spectrum database includes a library spectrum obtained by spectral preprocessing of the near-infrared spectrum of each of the known crude oil samples and standard data of key physical properties of each of the known crude oil samples, and the library spectra of the plurality of known crude oil samples constitute a first spectrum matrix; Acquire a near infrared spectrum of a target crude oil sample and perform the spectrum preprocessing on the near infrared spectrum of the target crude oil sample to obtain a second spectrum; wherein the target crude oil sample is obtained by mixing a plurality of component crude oils, and the component crude oils include a specified component crude oil and an undetermined component crude oil; The spectrum to be fitted is calculated according to the following formula (1): Where C is the spectrum to be fitted, B is the second spectrum, A i is the library spectrum of the i-th specified component crude oil, j i For the specified component crude oil A i The mixing ratio of n is the number of types of crude oil of the specified component; Fitting the spectrum to be fitted by using the first spectrum matrix to obtain fitting coefficients of the crude oil with undetermined components; Determining the mixing ratio of the crude oil of undetermined components according to the fitting coefficient; The mixing ratio of the undetermined component crude oil and the mixing ratio of the specified component crude oil are normalized to obtain a mixing formula of the target crude oil sample.

2. The method according to claim 1, wherein: The spectrum preprocessing includes: The absorbance of the characteristic spectral region of the near infrared spectrum is subjected to first-order differential processing and normalized according to the following formula (2): Among them, x nor is the absorbance vector of the normalized spectrum, x0 is the absorbance vector of the original spectrum, is the average spectral vector and is calculated according to the following formula (3), m is the number of wavelength points for collecting spectral absorbance, k is the sampling point number for collecting spectral absorbance, k = 1, 2, ..., m, 3. The method according to claim 2, wherein: The characteristic spectrum range is 4000-4700 cm -1 and 5300~6000cm -1 .

4. The method according to claim 1, wherein: The method includes: Using a non-negative constrained least square method to determine non-zero fitting coefficients in the fitting coefficients, and normalizing the non-zero fitting coefficients to obtain normalized fitting coefficients; The mixing ratio of the crude oil with undetermined components is determined according to the normalized fitting coefficient.

5. The method according to claim 4, wherein: The method includes: The fitting is performed according to the following formula (4): Wherein, p is the spectrum to be fitted, v i is the library spectrum involved in the fitting, t is the number of library spectra involved in the fitting, a i is the fitting coefficient corresponding to the ith library spectrum and satisfies the objective function shown in the following formula (5): The non-zero fitting coefficients among all the obtained fitting coefficients are extracted and normalized according to the following formula (6): Among them, b i is the normalized fitting coefficient of the i-th crude oil with unknown components, and g is the number of library spectra corresponding to non-zero fitting coefficients.

6. The method according to claim 5, wherein: The method includes: The mixing ratio of the undetermined crude oil is calculated according to the following formula (7): Among them, m i is the mixing ratio of the i-th crude oil with uncertain components, b i is the normalized fitting coefficient of the i-th crude oil with uncertain components, j i For the specified component crude oil A i The mixing ratio of n is the number of types of crude oil of the specified component.

7. The method according to claim 1, wherein: The key physical properties include at least one of density, acid value, carbon residue value, sulfur content, nitrogen content, wax content, resin content and asphaltene content.

8. The method according to claim 7, wherein: The density is tested according to standard method SH / T0604-2000; The acid value is tested according to the standard method GB / T 7304-2014; The carbon residue value is tested according to the standard method GB / T 17144; The sulfur content is tested according to the standard method GB / T17040-2008; The nitrogen content is tested according to the standard method GB / T 17674; The wax content is tested according to standard method SY / T 0537; The colloid content is tested according to the standard method SY / T 7550; The asphaltene content is measured according to the standard method SY / T 7550.

9. The method according to claim 1, wherein: The near infrared spectrum is obtained by using a Fourier transform near infrared spectrometer.

10. The method according to claim 1, wherein: The near infrared spectroscopy detection conditions of the known crude oil sample and the target crude oil sample independently include: a resolution of 2 to 16 cm -1 , the wave number range is 4000~10000cm -1 , scan times 64 times.

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