X-ray diffraction mineral quantitative analysis reference intensity calculation method

Abstract

This invention discloses a method for calculating the reference intensity of X-ray diffraction mineral quantitative analysis, relating to the field of oil and gas exploration and development technology. This invention utilizes the X-ray diffraction full-spectrum fitting method to design an initial crystal structure model of the mineral, construct a theoretical X-ray diffraction spectrum, refine the mineral crystal structure parameters and peak shape function parameters, fit the mineral percentage content, and derive the required reference intensity K value using the mineral percentage content calculation formula from the standard (SY / T5163-2018) "X-ray Diffraction Analysis Method for Clay Minerals and Common Non-Clay Minerals in Sedimentary Rocks". This allows for the true realization of quantitative X-ray diffraction mineral analysis for sedimentary rocks, igneous rocks, and metamorphic rocks.

Description

Technical Field

[0001] This invention relates to the field of oil and gas exploration and development technology, and more specifically to the field of X-ray diffraction mineral quantitative analysis reference intensity calculation method. Background Technology

[0002] X-ray diffraction (XRD) is a crucial technique in the field of spectroscopy. Powder X-ray diffraction, in particular, has been widely applied since its invention to qualitative / quantitative analysis of minerals, determination of unit cell parameters, isomorphic / isomorphic analysis, ordered / disordered structure research, and petrographic studies. It also shows broad application prospects in emerging fields such as mineral crystallization processes and phase transformations, mineral surface phase analysis, mineral defect research, and mineral crystal structure determination. Among these, X-ray diffraction for qualitative / quantitative mineral analysis is an extremely important and frequently used method for quantitative analysis of mineral components in sedimentary, igneous, and metamorphic rocks. It holds immense significance for reservoir evaluation, reservoir stimulation, well logging interpretation, diagenesis, and sedimentary environment research in oil and gas exploration and development.

[0003] Large areas of Permian igneous rocks are developed in the western Sichuan Basin, with significant exploration discoveries made at the end of 2018. Igneous rocks exhibit extremely complex and diverse lithologies. The existing standard method (SY / T 5163-2018), "X-ray Diffraction Analysis Method for Clay Minerals and Common Non-Clay Minerals in Sedimentary Rocks," is widely used for the quantitative analysis of crystalline components in sedimentary rocks. However, this standard lacks a reference intensity K-value—a calculation parameter for the quantitative analysis of common minerals in igneous rocks such as pyroxene, sphene, biotite, amphibole, and mafic ore. Similarly, there is no reference intensity K-value for common metamorphic rocks such as andalusite, kyanite, and sillimanite. Therefore, directly applying the existing standard cannot achieve quantitative analysis of mineral components in igneous and metamorphic rocks.

[0004] Because the minerals in igneous and metamorphic rocks are often poorly crystallized and many are in altered states, it is impossible to calculate the corresponding reference intensity K value by finding mineral standard samples with high crystallinity and no impurities. Therefore, there is an urgent need to find an effective and reliable method to calculate the reference intensity K value so as to truly realize the quantitative analysis of mineral components in igneous and metamorphic rocks through X-ray diffraction analysis. Summary of the Invention

[0005] The purpose of this invention is to provide a method for calculating the reference intensity of X-ray diffraction mineral quantitative analysis in order to solve the above-mentioned technical problems.

[0006] To achieve the above objectives, the present invention specifically adopts the following technical solution:

[0007] A method for calculating reference intensity in quantitative mineral analysis using X-ray diffraction includes the following steps:

[0008] S1. Select rock samples and determine the types of minerals and their elemental contents in the rocks by means of thin section identification, scanning electron microscopy and energy dispersive spectroscopy.

[0009] S2. After washing and drying the rock sample, grind it into powder and mix it thoroughly.

[0010] S3. Select a portion of the fully mixed sample from step S2 as the analytical sample, conduct X-ray spectrometry testing, and obtain the X-ray diffraction experimental spectrum of the analytical sample.

[0011] S4. Based on the mineral types and elemental contents identified in step S1, and in conjunction with the X-ray diffraction and powder diffraction crystal structure database, design an initial crystal structure model for the mineral.

[0012] S5. Based on the initial crystal structure model of the mineral designed in step S4, use the Voigt function or the Pseudo-Voigt function to fit the X-ray diffraction peak shape and construct the theoretical X-ray diffraction spectrum.

[0013] S6. Using the nonlinear least squares method, refine the crystal structure parameters and peak shape function parameters corresponding to the X-ray diffraction theoretical spectrum constructed in step S5, so that the X-ray diffraction theoretical spectrum in step S5 and the X-ray diffraction experimental spectrum in step S3 match to the maximum extent.

[0014] S7. Calculate the mineral percentage based on the final fitted X-ray diffraction theoretical spectrum from step S6.

[0015] S8. Derive the formula for calculating the reference intensity K value by using the mineral percentage calculation formula in "X-ray Diffraction Analysis Method of Clay Minerals and Common Non-Clay Minerals in Sedimentary Rocks";

[0016] S9. Using the percentage content of the known reference strength K value mineral and its reference strength K value calculated in step S7, and combining it with the percentage content of the unknown reference strength K value mineral calculated in step S7, we can substitute it into the calculation formula derived in step S8 to obtain the reference strength K value of the unknown reference strength K value mineral.

[0017] S10. By obtaining the reference strength K value of the same mineral in multiple analytical samples and then calculating their arithmetic mean, the optimal reference strength K value suitable for the stratum or block where the sample is located is determined.

[0018] As a preferred technical solution, in step S4, the initial crystal structure model of the mineral includes the correct space group, lattice constant, atomic coordinates, occupancy rate, and temperature factor.

[0019] In step S5, the expressions for the Voigt function and the Pseudo-Voigt function are as follows:

[0020]

[0021] G ik =ηL ik +(1-η)g ik ;

[0022] In the formula, G ik 2θ represents the diffraction intensity at the i-th point on the k-th diffraction peak in the diffraction spectrum. k 2θ is the Bragg diffraction angle of the k-th diffraction peak. i β is the Bragg diffraction angle at the i-th point on the k-th diffraction peak; c β is the integral width of the Lorentz component in the Voigt function; g Ω is the integral width of the Gaussian component in the Voigt function; Re is the real part of the function; η is the fraction of the Lorentz component in the Pseudo-Voigt function; L ik For the Lorentz function; g ik It is a Gaussian function.

[0023] As a preferred technical solution, in step S6, the expression for the nonlinear least squares method is:

[0024]

[0025] In the formula, w i =1 / Y i Y is a weighting factor based on technical statistics. io Y represents the measured value of the X-ray diffraction experimental spectrum. ic The theoretical value of the X-ray diffraction pattern is given; the optimal fit occurs when the M value is minimized.

[0026] As a preferred technical solution, in step S6, the method for judging the degree of agreement between the two X-ray diffraction experimental spectra is that the difference lines of the difference maps of the two are relatively concentrated at the 0 value line, and the convergence scale R factor is less than 5 and the goodness factor GofF is less than 1.5, which meets the quality requirements for the full spectrum fitting correction of the Ritterwald pattern of X-ray diffraction.

[0027] Wherein: the convergence scaling R factor includes the residual variance factor R p Weighted residual variance factor R wp Integral intensity residual variance factor R B The expected value R of the weighted residual variance factor e .

[0028] As a preferred technical solution, in step S7, the expression for calculating the mineral percentage content using X-ray diffraction theoretical spectra is as follows:

[0029]

[0030] In the formula, S i Z represents the calibration factor for mineral i; i Indicates the number of atoms or chemical formulas contained in the unit cell of mineral i; M i V represents the molar mass of mineral i; iu Let be the unit cell volume of mineral i.

[0031] As a preferred technical solution, in step S8, the derived formula for calculating the reference strength K value is as follows:

[0032]

[0033] In the formula, K i Indicates the reference strength of mineral i; I i X represents the integrated intensity of the selected diffraction peak for mineral i; unknown This indicates the percentage content of minerals with unknown K values, expressed as %; K unknown Indicates the reference strength of a mineral with an unknown K-value; I unknown This represents the integral intensity of the selected diffraction peak for a mineral with an unknown K value.

[0034] As a preferred technical solution, in step S1, rock thin section identification and scanning electron microscopy are used to determine the optical properties and morphological characteristics of minerals under a microscope, and energy dispersive spectroscopy is used to determine the elemental composition and content of minerals. The combination of the three methods determines the mineral type and its elemental content.

[0035] As a preferred technical solution, in step S2, after washing and drying the rock sample, the selected rock sample is crushed and ground until all particles are less than 74μm in size, and there is no grainy feeling when rubbed between the fingers, and then it is thoroughly mixed.

[0036] As a preferred technical solution, in step S3, the X-ray diffraction pattern test of the analytical sample must meet the requirements of the industry standard SY / T 5163-2018 "X-ray diffraction analysis method for clay minerals and common non-clay minerals in sedimentary rocks".

[0037] As a preferred technical solution, in step S4, the X-ray diffraction and powder diffraction crystal structure database refers to ICDD (International Powder Diffraction Database) or ICSD (International Inorganic Crystal Structure Database).

[0038] As a preferred technical solution, in step S9, the reference intensity K value of the mineral with known reference intensity K value is obtained by looking up the K value table of common minerals. Specifically, the reference intensity K value of the mineral with known reference intensity K value is obtained by referring to the "K value table of common minerals" in Appendix F, Table F.1 of the standard (SY / T5163-2018) "X-ray diffraction analysis method for clay minerals and common non-clay minerals in sedimentary rocks".

[0039] The beneficial effects of this invention are as follows:

[0040] 1. In the petroleum industry standard SY / T 5163-2018 "X-ray Diffraction Analysis Method for Clay Minerals and Common Non-Clay Minerals in Sedimentary Rocks," the reference intensity K value of pure corundum is used as a benchmark. The relationship between the X-ray diffraction integral intensity of the tested mineral and its mass fraction and X-ray diffraction integral intensity is established by finding a pure standard sample, and the reference intensity K value of the pure standard sample is then calculated and used as the reference intensity K value for the mineral. However, in reality, minerals in natural rocks exhibit polymorphism and isomorphism, and elements in minerals are often replaced by other elements. Furthermore, the crystal structure changes due to factors such as temperature, pressure, and chemically active fluids at different strata depths, resulting in variations in X-ray diffraction capabilities. Therefore, simply using the reference intensity K value of a pure standard sample as the reference intensity K value for the tested mineral inherently contains errors. This invention establishes a method for calculating the reference intensity parameter K value without a standard sample, thus avoiding the difficulty of finding a pure standard sample.

[0041] 2. The XRD full-spectrum fitting method used in this invention is a physical method. Its greatest advantage is that it analyzes the entire diffraction spectrum based on X-ray diffraction, eliminating the disadvantages of chemical measurement methods that introduce influencing factors that alter the state of matter. It is a standard-free quantitative phase analysis method based on crystal structure calculations and powder diffraction full spectra, which can reduce the influence of some systematic errors on the quantitative results. The reference intensity K value calculated by this method is more suitable for the characteristics of the sample itself, avoiding the errors caused by the incompatibility of the standard sample.

[0042] 3. Because the existing methods and standards cannot effectively handle overlapping diffraction peaks, it is impossible to determine the percentage content of minerals when there are overlapping diffraction peaks in the X-ray diffraction pattern. This invention can effectively handle overlapping diffraction peaks by adjusting the peak shape parameters of the theoretical diffraction pattern. It can also obtain good results for complex diffraction patterns (up to a dozen phases) and broad diffraction peaks, and can accurately identify mineral content. Therefore, it can more accurately calculate the reference intensity K value of minerals.

[0043] 4. The study of rock and mineral composition is one of the fundamental tasks in oil and gas exploration and development. As the field of oil and gas exploration and development continues to delve into deep and ultra-deep reservoirs, the reservoir rock and mineral objects faced are more complex and diverse than before. The study of rock and mineral composition has become a very important topic. The method for calculating the reference intensity K value of X-ray diffraction established in this invention can effectively solve the quantitative problem of different types of rock and mineral composition, and provide more reliable data support for exploration and development.

[0044] 5. The present invention establishes a set of reference intensity K-value tables for quantitative analysis of X-ray diffraction minerals suitable for a certain oil and gas exploration block by calculating the reference intensity K-values ​​of the same mineral in multiple samples. By using the established reference intensity K-value tables, rapid analysis of a large number of samples in the block can be achieved, which can greatly improve the efficiency of analytical experiments.

[0045] 6. The method for calculating the reference intensity K value in this invention is based on the "K value table of common minerals" in Appendix F, Table F.1 of the standard (SY / T 5163-2018) "X-ray diffraction analysis method for clay minerals and common non-clay minerals in sedimentary rocks". It specifically solves the problem of how to obtain the reference intensity K value of minerals not included in the table. By using the method established by this invention, this standard can be widely implemented and promoted in the field of igneous and metamorphic rocks, further standardizing and maturing the X-ray diffraction analysis industry standard, and promoting the innovative development of X-ray diffraction analysis technology. Detailed Implementation

[0046] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments.

[0047] Therefore, the following detailed description of embodiments of the present invention is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0048] Example 1

[0049] As a preferred embodiment of the present invention, this embodiment discloses a method for calculating the reference intensity of X-ray diffraction mineral quantitative analysis, the method comprising the following steps:

[0050] S1. Select rock samples and determine the types of minerals and their elemental contents in the rocks by means of thin section identification, scanning electron microscopy and energy dispersive spectroscopy.

[0051] S2. After washing and drying the rock sample, grind it into powder and mix it thoroughly.

[0052] S3. Select a portion of the fully mixed sample from step S2 as the analytical sample, conduct X-ray spectrometry testing, and obtain the X-ray diffraction experimental spectrum of the analytical sample.

[0053] S4. Based on the mineral types and elemental contents identified in step S1, and in conjunction with the X-ray diffraction and powder diffraction crystal structure database, design an initial crystal structure model for the mineral.

[0054] S5. Based on the initial crystal structure model of the mineral designed in step S4, use the Voigt function or the Pseudo-Voigt function to fit the X-ray diffraction peak shape and construct the theoretical X-ray diffraction spectrum.

[0055] S6. Using the nonlinear least squares method, refine the crystal structure parameters and peak shape function parameters corresponding to the X-ray diffraction theoretical spectrum constructed in step S5, so that the X-ray diffraction theoretical spectrum in step S5 and the X-ray diffraction experimental spectrum in step S3 match to the maximum extent.

[0056] S7. Calculate the mineral percentage based on the final fitted X-ray diffraction theoretical spectrum from step S6.

[0057] S8. Derive the formula for calculating the reference intensity K value by using the mineral percentage calculation formula in "X-ray Diffraction Analysis Method of Clay Minerals and Common Non-Clay Minerals in Sedimentary Rocks";

[0058] S9. Using the percentage content of the known reference strength K value mineral and its reference strength K value calculated in step S7, and combining it with the percentage content of the unknown reference strength K value mineral calculated in step S7, we can substitute it into the calculation formula derived in step S8 to obtain the reference strength K value of the unknown reference strength K value mineral.

[0059] S10. By obtaining the reference strength K value of the same mineral in multiple analytical samples and then calculating their arithmetic mean, the optimal reference strength K value suitable for the stratum or block where the sample is located is determined.

[0060] Example 2

[0061] As another preferred embodiment of the present invention, this embodiment discloses a method for calculating the reference intensity of X-ray diffraction mineral quantitative analysis, the method comprising the following steps:

[0062] S1. Select rock samples and determine the types of minerals and their elemental contents in the rocks by means of thin section identification, scanning electron microscopy and energy dispersive spectroscopy.

[0063] S2. After washing and drying the rock samples, crush and grind the selected rock samples until all particle sizes are less than 74μm, and there is no grainy feeling when rubbed between the fingers, and then mix them thoroughly.

[0064] S3. Select a portion of the fully mixed sample from step S2 as the analytical sample and conduct X-ray diffraction testing, which must meet the requirements of industry standard SY / T 5163-2018 "X-ray Diffraction Analysis Methods for Clay Minerals and Common Non-Clay Minerals in Sedimentary Rocks"; obtain the X-ray diffraction experimental spectrum of the analytical sample.

[0065] S4. Based on the mineral types and elemental contents identified in step S1, and in conjunction with the X-ray diffraction and powder diffraction crystal structure database, design an initial crystal structure model for the mineral; where the X-ray diffraction and powder diffraction crystal structure database refers to ICDD (International Powder Diffraction Database) or ICSD (International Inorganic Crystal Structure Database); the initial crystal structure model for the mineral includes the correct space group, lattice constant, atomic coordinates, occupancy, and temperature factor.

[0066] S5. Based on the initial crystal structure model of the mineral designed in step S4, use the Voigt function or the Pseudo-Voigt function to fit the X-ray diffraction peak shape and construct the theoretical X-ray diffraction spectrum.

[0067] S6. Using the nonlinear least squares method, refine the crystal structure parameters and peak shape function parameters corresponding to the X-ray diffraction theoretical spectrum constructed in step S5, so that the X-ray diffraction theoretical spectrum in step S5 and the X-ray diffraction experimental spectrum in step S3 match to the maximum extent.

[0068] S7. Calculate the mineral percentage based on the final fitted X-ray diffraction theoretical spectrum from step S6.

[0069] S8. Derive the formula for calculating the reference intensity K value by using the mineral percentage calculation formula in "X-ray Diffraction Analysis Method of Clay Minerals and Common Non-Clay Minerals in Sedimentary Rocks";

[0070] S9. Using the percentage content of the known reference strength K value mineral and its reference strength K value calculated in step S7, and combining it with the percentage content of the unknown reference strength K value mineral calculated in step S7, we can substitute it into the calculation formula derived in step S8 to obtain the reference strength K value of the unknown reference strength K value mineral.

[0071] S10. By obtaining the reference strength K value of the same mineral in multiple analytical samples and then calculating their arithmetic mean, the optimal reference strength K value suitable for the stratum or block where the sample is located is determined.

[0072] Example 3

[0073] As another preferred embodiment of the present invention, based on the above embodiment 1 or embodiment 2, further, in step S5, the expressions for the Voigt function and the Pseudo-Voigt function are respectively:

[0074]

[0075] G ik =ηL ik +(1-η)g ik

[0076] In the formula, G ik 2θ represents the diffraction intensity at the i-th point on the k-th diffraction peak in the diffraction spectrum. k 2θ is the Bragg diffraction angle of the k-th diffraction peak. i β is the Bragg diffraction angle at the i-th point on the k-th diffraction peak; c β is the integral width of the Lorentz component in the Voigt function; g Ω is the integral width of the Gaussian component in the Voigt function; Re is the real part of the function; η is the fraction of the Lorentz component in the PV function; L ik For the Lorentz function; g ik It is a Gaussian function.

[0077] In another implementation of this embodiment, the expression for the nonlinear least squares method in step S6 is:

[0078]

[0079] In the formula, w i =1 / Y i Y is a weighting factor based on technical statistics. io Y represents the measured value of the X-ray diffraction experimental spectrum. ic The theoretical value of the X-ray diffraction pattern is given; the optimal fit occurs when the M value is minimized.

[0080] Furthermore, in step S6, the method for determining the degree of agreement between the two X-ray diffraction experimental spectra is that the difference lines of the difference maps of the two are relatively concentrated at the 0 value line, and the convergence scale R factor is less than 5 and the goodness factor GofF is less than 1.5.

[0081] Wherein: the convergence scaling R factor includes the residual variance factor R p Weighted residual variance factor R wp Integral intensity residual variance factor R B The expected value R of the weighted residual variance factor e .

[0082] In step S7, the expression for calculating the mineral percentage content using X-ray diffraction theoretical spectra is as follows:

[0083]

[0084] In the formula, S i Z represents the calibration factor for mineral i; i Indicates the number of atoms or chemical formulas contained in the unit cell of mineral i; M i V represents the molar mass of mineral i; iu Let be the unit cell volume of mineral i.

[0085] In step S8, the derived formula for calculating the reference strength K value is as follows:

[0086] In the formula, K i Indicates the reference strength of mineral i; I i X represents the integrated intensity of the selected diffraction peak for mineral i; unknown This indicates the percentage content of minerals with unknown K values, expressed as %; K unknown Indicates the reference strength of a mineral with an unknown K-value; I unknown This represents the integral intensity of the selected diffraction peak for a mineral with an unknown K value.

[0087] In step S9, the reference intensity K value of the mineral with known reference intensity K value can be found in the "K value table of common minerals" in Appendix F, Table F.1 of the standard (SY / T5163-2018) X-ray diffraction analysis method for clay minerals and common non-clay minerals in sedimentary rocks.

[0088] Example 4

[0089] As another preferred embodiment of the present invention, this embodiment describes the process of establishing a reference strength K-value table for Permian igneous rocks in the western Sichuan Basin. The details are as follows:

[0090] First, the percentage content X of minerals with known K values ​​(including quartz, ferroalloy, and calcite) in the sample was obtained by XRD full-spectrum fitting method. i The K-values ​​of minerals with known K-values ​​(quartz, ferrodolomite, and calcite) were obtained by referring to Table F.1 in Appendix F of the standard (SY / T5163-2018) "X-ray Diffraction Analysis Methods for Clay Minerals and Common Non-Clay Minerals in Sedimentary Rocks," which lists the K-values ​​of common minerals. Then, the diffraction integral intensity I of the minerals with known K-values ​​(quartz, ferrodolomite, and calcite) was obtained through X-ray diffraction experiments. i ; Secondly, the obtained X i K i I i Substitute the numerical value into the following relation (1) to calculate the denominator factor. Finally, the percentage content X of the mineral with unknown K value in the sample was obtained by XRD full-spectrum fitting method. unknown The diffraction integral intensity I was obtained from the X-ray diffraction experimental spectrum. unknown According to relation (2), the K value (K) of the unknown K-value mineral is obtained. unknown ), see formula:

[0091]

[0092] In the formula, X i K represents the percentage content of mineral i in the full spectrum fitting, in %. i Indicates the reference strength of mineral i; I i This represents the integrated intensity of the selected diffraction peak for mineral i.

[0093]

[0094] In the formula, X unknown This indicates the percentage content of minerals with unknown K values, expressed as %; K unknown Indicates the reference strength of a mineral with an unknown K-value; I unknown This represents the integral intensity of the selected diffraction peak for a mineral with an unknown K value.

[0095] To reduce the computational difficulty, X unknown I unknown and the denominator factors calculated in equation (1) Substituting the overall numerical value into the relational formula, the K value of the unknown K-value mineral can be calculated. unknown .

[0096] When calculating the denominator factor using quartz, dolomite, and calcite from igneous rocks as known K-value minerals, the calculation results may be biased due to factors such as X-ray diffraction matrix effects and preferred orientation. To reduce systematic errors, the denominator factor is first calculated for the same sample. The arithmetic mean of the reference intensity K values ​​is obtained by using the XRD full spectrum fitting analysis results of multiple different samples, and then the arithmetic mean of the calculated reference intensity K values ​​is used as the optimal reference intensity K value.

[0097] In sedimentary rocks, ferrodolithium, quartz, calcite, and potassium feldspar have relatively similar crystal structures in igneous rocks, and these four minerals are mostly formed through sedimentary processes. Therefore, the K-values ​​for these four minerals are adopted from the standard sedimentary rock method. Based on this, the K-values ​​were repeatedly calculated and verified using XRD full-spectrum fitting results, and a table of K-values ​​suitable for X-ray diffraction analysis of common minerals in Permian igneous rocks in western Sichuan Basin was established. Table 1 shows the K-values ​​for X-ray diffraction analysis of common minerals in Permian igneous rocks in western Sichuan Basin.

[0098] Table 1

[0099]

[0100]

[0101] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for calculating the reference intensity of X-ray diffraction mineral quantitative analysis, characterized in that, Includes the following steps: S1. Select rock samples and determine the types of minerals and their elemental contents in the rocks by means of thin section identification, scanning electron microscopy and energy dispersive spectroscopy. S2. After washing and drying the rock sample, grind it into powder and mix it thoroughly. S3. Select a portion of the fully mixed sample from step S2 as the analytical sample, conduct X-ray spectrometry testing, and obtain the X-ray diffraction experimental spectrum of the analytical sample. S4. Based on the mineral types and elemental contents identified in step S1, and in conjunction with the X-ray diffraction and powder diffraction crystal structure database, design an initial crystal structure model for the mineral. S5. Based on the initial crystal structure model of the mineral designed in step S4, apply the Voigt function or Pseudo function. Voigt pseudo-Voigt function is used to fit the X-ray diffraction peak shape and construct the theoretical X-ray diffraction spectrum; S6. Using the nonlinear least squares method, refine the crystal structure parameters and peak shape function parameters corresponding to the X-ray diffraction theoretical spectrum constructed in step S5, so that the X-ray diffraction theoretical spectrum in step S5 and the X-ray diffraction experimental spectrum in step S3 match to the maximum extent. S7. Calculate the mineral percentage based on the final fitted X-ray diffraction theoretical spectrum from step S6. S8. Derive the formula for calculating the reference intensity K value by using the mineral percentage calculation formula in "X-ray Diffraction Analysis Method of Clay Minerals and Common Non-Clay Minerals in Sedimentary Rocks"; S9. Using the percentage content of the known reference strength K value mineral and its reference strength K value calculated in step S7, and combining it with the percentage content of the unknown reference strength K value mineral calculated in step S7, we can substitute it into the calculation formula derived in step S8 to obtain the reference strength K value of the unknown reference strength K value mineral. S10. By obtaining the reference strength K value of the same mineral in multiple analytical samples and then calculating their arithmetic mean, the optimal reference strength K value suitable for the stratum or block where the sample is located is determined. In step S4, the initial crystal structure model of the mineral includes the correct space group, lattice constant, atomic coordinates, occupancy rate, and temperature factor. In step S5, the Voigt function and Pseudo... The Voigt pseudo-Voigt function expressions are as follows: G ik =ηL ik +(1 h)g ik ; In the formula, G ik 2θ represents the diffraction intensity at the i-th point on the k-th diffraction peak in the diffraction spectrum. k 2θ is the Bragg diffraction angle of the k-th diffraction peak. i β is the Bragg diffraction angle at the i-th point on the k-th diffraction peak; c β is the integral width of the Lorentz component in the Voigt function; g Ω is the integral width of the Gaussian component in the Voigt function; Re is the composite error function; η is the real part of the function; and η is the Pseudo function. The fraction of the Lorentz component in the Voigt function; L ik For the Lorentz function; g ik It is a Gaussian function; In step S6, the expression for the nonlinear least squares method is: wherein w i = 1 / Y i is the weight factor based on the statistical technique, Y io is the measured value of the X-ray diffraction experimental spectrum, Y ic is the theoretical value of the X-ray diffraction spectrum; the fitting is optimal when the value of M is the smallest.

2. The method for calculating the reference intensity of X-ray diffraction mineral quantitative analysis according to claim 1, characterized in that, In step S6, the method for determining the degree of agreement between the two X-ray diffraction experimental spectra is that the difference lines of the difference plots of the two are relatively concentrated at the 0 value line, and the convergence scale R factor is less than 5 and the goodness factor GofF is less than 1.

5. Wherein: the convergence scaling R factor includes the residual variance factor R p Weighted residual variance factor R wp Integral intensity residual variance factor R B The expected value R of the weighted residual variance factor e .

3. The method for calculating the reference intensity of X-ray diffraction mineral quantitative analysis according to claim 1, characterized in that, In step S7, the expression for calculating the mineral percentage content using X-ray diffraction theoretical spectra is as follows: In the formula, S i Z represents the calibration factor for mineral i; i Indicates the number of atoms or chemical formulas contained in the unit cell of mineral i; M i V represents the molar mass of mineral i; iu Let be the unit cell volume of mineral i.

4. The method for calculating the reference intensity of X-ray diffraction mineral quantitative analysis according to claim 1, characterized in that, In step S8, the derived formula for calculating the reference strength K value is as follows: In the formula, K i Indicates the reference strength of mineral i; I i X represents the integrated intensity of the selected diffraction peak for mineral i; unknown This indicates the percentage content of minerals with unknown K values, expressed as %; K unknown Indicates the reference strength of a mineral with an unknown K-value; I unknown This represents the integral intensity of the selected diffraction peak for a mineral with an unknown K value.

5. The method for calculating the reference intensity of X-ray diffraction mineral quantitative analysis according to any one of claims 1 to 4, characterized in that, In step S2, after washing and drying the rock sample, the selected rock sample is crushed and ground until all particles are less than 74μm in size and can be rubbed between the fingers without feeling grainy, and then thoroughly mixed.

6. The method for calculating the reference intensity of X-ray diffraction mineral quantitative analysis as described in any one of claims 1 to 4, characterized in that: In step S3, X-ray diffraction pattern testing of the analytical sample must meet the industry standard SY / T 5163. Requirements of 2018 "X-ray Diffraction Analysis Methods for Clay Minerals and Common Non-Clay Minerals in Sedimentary Rocks".

7. The method for calculating the reference intensity of X-ray diffraction mineral quantitative analysis according to any one of claims 1 to 4, characterized in that, In step S4, the X-ray diffraction and powder diffraction crystal structure database refers to the International Powder Diffraction Database or the International Inorganic Crystal Structure Database.

8. The method for calculating the reference intensity of X-ray diffraction mineral quantitative analysis according to claim 1, characterized in that, In step S9, the reference strength K value of a known mineral is obtained by looking up the K value table of common minerals.

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