A molecular simulation method for calculating adsorbed oil content in shale

Abstract

The application discloses a molecular simulation method for calculating the content of absorbed oil in shale. The method of the application establishes a theoretical calculation model of the content of absorbed oil in shale, can calculate the content of absorbed oil in shale samples under different mineral component contents, different pore sizes, different specific surface areas and different temperature and pressure conditions, makes up for the deficiency of the test ability of geology-geochemistry experiments on the nanometer pore scale of shale, makes up for the problem that previous geology factors such as temperature and pressure are ignored to affect the content of absorbed oil, improves the accuracy and operability of the calculation result of the content of absorbed oil, provides an important parameter for shale oil mobility evaluation, and on the other hand, the theoretical calculation model established by the application has universality, can be applied to different geological conditions in the case of lacking samples, and has important significance for the evaluation of overseas shale oil and gas resource potential.

Description

Technical Field

[0001] This invention belongs to the field of unconventional oil and gas geology, specifically relating to a molecular simulation method for calculating the adsorbed oil content in shale. Background Technology

[0002] Existing research findings on the testing of adsorbed oil content in shale mainly include the following aspects: Jiang Qigui et al. disclosed a method for testing adsorbed oil content using multi-temperature-stage pyrolysis experiments. They used a pyrolysis apparatus to conduct pyrolysis experiments on shale samples at a constant heating rate, raising the temperature from 350℃ to 450℃ at a rate of 25℃ / min and holding it at that temperature for 1 min to obtain the pyrolysis hydrocarbon content S. 2-1 The figure represents the adsorbed oil content (2016, Petroleum Experimental Geology, Vol. 38, No. 6). This method measures the adsorbed oil content of mudstone and shale samples preserved under normal pressure and surface temperature conditions, without considering the influence of formation temperature and pressure on the adsorbed oil content of mudstone and shale.

[0003] Li Junqian et al. established a mathematical model for quantitative evaluation of adsorbed and free oil in shale based on capillary condensation. Drawing on the process of hydrocarbon vapor adsorption in porous media, they extended hydrocarbon adsorption under experimental conditions to hydrocarbon adsorption under reservoir conditions, establishing an evaluation method for the adsorption and mobility within the oil-saturated pores of shale reservoirs. They correlated nitrogen adsorption / desorption experiments with hydrocarbon vapor adsorption experiments, and quantitatively calculated the adsorption, mobility, and total amount of shale oil, as well as the percentage of each (Patent CN 106547966 B, "An Evaluation Model for Shale Oil Adsorption and Mobility and Its Establishment and Application Method" and article: 2019, Petroleum and Natural Gas Geology, Vol. 40, No. 3). However, this method has certain requirements for the sample and relatively little consideration for the influence of different mineral components, kerogen content, temperature, pressure, and other conditions on the adsorption amount.

[0004] Liu Bo et al. disclosed a method for detecting adsorbed and free oil in inorganic mineral-bearing oil in shale and mudstone (patent CN111912958 A). This method uses molecular dynamics simulations on a kaolinite pore-shale oil model to determine the oil adsorption capacity per unit area of ​​the kaolinite surface and calculate the adsorption amount. The free oil amount is obtained by subtracting the adsorbed oil amount from the existing oil amount. This method primarily focuses on the adsorbed oil amount from inorganic minerals in shale and mudstone, without addressing the adsorption oil amount from kerogen, and does not consider correcting the adsorbed oil amount using experimental test results.

[0005] Zhi Dongming et al. disclosed a method and apparatus for continuous characterization of adsorbed oil and free oil content in shale oil (patent CN 110687612 B). This method is based on extensive experiments and analytical calculations on core samples to determine the lower limit of adsorbed oil content, and has strong practicality. However, this type of characterization method based on physical experiments often requires a large number of samples and relatively harsh experimental conditions. Considering the limitations of testing costs and the detection limits of analytical instruments, the sampling, experimental, and equipment costs of this type of method are often high, and it is difficult to achieve evaluation and characterization under extreme conditions. Summary of the Invention

[0006] To address the problems existing in the prior art, the present invention aims to provide a molecular simulation method for calculating the adsorbed oil content in shale. By establishing a theoretical calculation model for the amount of adsorbed oil in shale, the method can improve the accuracy and operability of the calculation results.

[0007] Therefore, the present invention provides a molecular simulation method for calculating the adsorbed oil content in shale, which includes the following steps:

[0008] (1) Obtain information on mineral composition, kerogen and shale oil composition, specific surface area and pore structure of different shale samples;

[0009] (2) Select representative indicators from the mineral composition information, kerogen information, shale oil composition information, specific surface area and pore structure information of the obtained shale samples respectively, and establish molecular models to simulate the corresponding shale samples based on the representative indicators.

[0010] (3) Using the molecular model established in step (2), molecular dynamics simulations were performed on different shale samples under different temperatures, pressures, specific surface areas and pore structures to obtain the shale oil adsorption density of shale samples under different temperatures, pressures, specific surface areas and pore structures, and a model was established to establish the relationship between the amount of adsorbed oil and the mineral composition, kerogen and specific surface area of ​​the shale samples.

[0011] (4) Correct the relationship model obtained in step (3) based on the actual laboratory measurement results to obtain the relationship between the correction factor and the shale adsorbed oil amount calculation model, and calculate the shale adsorbed oil amount.

[0012] According to the present invention, the mineral composition information refers to information that reflects the mineral composition of a shale sample, including but not limited to the specific types, categories, and contents of mineral components in the shale sample. In some embodiments of the present invention, the mineral composition information includes the specific types and contents of mineral components.

[0013] According to the present invention, the kerogen information refers to information that reflects the composition of kerogen in a shale sample, including but not limited to the type and content of kerogen in the shale sample. In some embodiments of the present invention, the kerogen information includes the type and content of kerogen.

[0014] According to the present invention, the shale oil composition information refers to information that reflects the composition of shale oil in shale, including but not limited to the specific component types, contained compounds, and their contents. In some embodiments of the present invention, the shale oil information includes the component types, contained compounds, and their contents of the shale oil.

[0015] According to the present invention, the shale oil composition information refers to information that reflects the composition of shale oil in shale, including but not limited to the specific component types, contained compounds and their contents in shale oil.

[0016] According to the present invention, the specific surface area and pore structure information includes, but is not limited to, the specific surface area and pore size of the shale sample. In some embodiments, the pore size is characterized by the average diameter of the pores.

[0017] According to the present invention, the mineral component includes inorganic mineral components but excludes kerogen. In some embodiments, the mineral component is an inorganic mineral component.

[0018] According to some embodiments of the present invention, in step (1), the mineral composition information contained in the shale sample is obtained by performing whole-rock X-ray diffraction analysis on the shale sample.

[0019] According to some embodiments of the present invention, in step (1), the shale oil component information contained in the shale sample is obtained by performing group component separation analysis on the chloroform bitumen extract of the fresh shale sample; the kerogen content is obtained by performing TOC testing on the shale sample after chloroform extraction; and the pyrolysis analysis is performed on the shale sample after chloroform extraction to obtain the pyrolysis hydrocarbon content S2, CO2 content S3, and peak pyrolysis hydrocarbon temperature T at 300-500℃. max The data were used to determine the type of kerogen contained in the shale samples based on the pyrolysis charts.

[0020] According to the present invention, the pyrolysis chart can be a self-built pyrolysis chart or a known pyrolysis chart related to the art. In some embodiments, the attached chart is used. Figure 2The pyrolysis chart shown is from Chen ZH, Jiang CQ, Lavoie D., et al., 2016. Model-assisted Rock-Eval data interpretation for sourcerock evaluation: Examples from producing and potential shale gas resourceplays. International Journal of Coal Geology 2016, 165: 290-302.

[0021] According to some embodiments of the present invention, in step (1), the shale oil component information contained in the shale sample is obtained by performing group component separation analysis on the petroleum produced from the shale reservoir corresponding to the shale sample.

[0022] According to some embodiments of the present invention, in step (1), the pore structure and specific surface area information of the shale sample are obtained by at least one of nuclear magnetic resonance, nitrogen adsorption and mercury intrusion porosimetry.

[0023] According to the present invention, the representative indicators refer to information that reflects the mineral composition, kerogen composition, and shale oil composition of the shale sample, as well as information that reflects the pore structure and specific surface area of ​​the shale sample.

[0024] According to the present invention, the representative indicator of the mineral composition information is information that reflects the mineral composition contained in the shale sample. This information can be complete information reflecting all the minerals contained in the shale sample, or it can be representative information reflecting only the minerals contained in the shale sample. In some embodiments, the representative indicator of the mineral composition information is the crystal structure and content of all the constituent minerals contained in the shale sample. In other embodiments, the representative indicator of the mineral composition information is the crystal structure and content of the major constituent minerals contained in the shale sample.

[0025] According to the present invention, the main constituent minerals refer to the constituent minerals with a high content in the shale sample, such as the constituent minerals with the highest content in the top 1-4.

[0026] According to the present invention, the representative indicator of the kerogen information is information that reflects the composition of the kerogen contained in the shale sample; it can be all information or representative information that reflects the composition of the kerogen contained in the shale sample. In some embodiments, the representative indicator of the kerogen information includes all kerogen types of the shale sample. In some embodiments, the representative indicator of the kerogen information is the main kerogen type of the shale sample. According to some embodiments of the present invention, the main kerogen type refers to the most typical type of kerogen contained in the shale sample.

[0027] According to the present invention, the representative indicators of the shale oil component information are representative information that reflects the composition of the shale oil contained in the shale sample. In some embodiments, the representative indicators of the shale oil component information include representative molecules of the main component types contained in the shale oil and the content of the main component types.

[0028] According to some embodiments of the present invention, the main component types in the shale oil include saturated hydrocarbons, aromatic hydrocarbons, non-hydrocarbons, and asphaltenes.

[0029] According to the present invention, the non-hydrocarbon component is a non-hydrocarbon component that is soluble in n-hexane.

[0030] According to the present invention, the representative molecule refers to a compound molecule contained in shale oil that reflects the composition of various component types of shale oil, such as the compound molecules that rank the top 1-4 in terms of abundance among the various component types of shale oil. In some embodiments, the representative molecule is the compound molecule with the highest abundance among the various component types contained in shale oil.

[0031] According to some embodiments of the present invention, representative indicators of the specific surface area and pore structure information include the pore size of the shale sample. According to the present invention, the pore size is characterized by an average diameter. According to some embodiments of the present invention, representative indicators of the specific surface area and pore structure information are the distribution range of the pore size of the shale sample.

[0032] According to some embodiments of the present invention, the step (2) of establishing a molecular model simulating the shale sample based on the representative indicators includes: establishing a molecular model based on the crystal structure of the constituent minerals of the shale sample and / or the kerogen type; and / or the content ratio of the main component types in the shale oil; and / or the pore size of the shale sample.

[0033] Specifically, establishing a molecular model based on the content ratio of the main component types in shale oil means that the total content ratio of representative molecules in the main component types is consistent with the content ratio of the main component types in the shale sample; establishing a molecular model based on the pore size of the shale sample means setting different pore diameters in the model according to the pore size of the shale sample.

[0034] According to some embodiments of the present invention, the molecular dynamics simulation method in step (2) is Monte Carlo molecular simulation.

[0035] According to some embodiments of the present invention, the molecular dynamics simulation in step (3) is achieved by a method including the following steps: setting the force field type for molecular models of shale samples with different mineral compositions, kerogen types, specific surface areas and pore structures and shale oil compositions, and applying simulated temperature and simulated pressure conditions to perform molecular dynamics simulations under different temperature, pressure, specific surface area and pore structure conditions.

[0036] According to some embodiments of the present invention, in step (3), establishing a relationship model between the amount of adsorbed oil and the mineral composition, kerogen, and specific surface area of ​​the shale sample includes establishing a relationship model between the amount of adsorbed oil in the shale sample and the content of mineral components, kerogen content, and specific surface area based on the obtained shale oil adsorption density of the shale sample, combined with the proportion of mineral components and kerogen in the shale sample and the specific surface area of ​​the shale sample.

[0037] According to some embodiments of the present invention, in step (4), the calculation model relationship of the shale adsorbed oil amount is as shown in equation (1):

[0038]

[0039] In equation (1), Q ao (T, P, r) represents the amount of oil adsorbed per unit area in shale under the conditions of temperature T, pressure P, and pore diameter r; ρ oil-x (T, P, r) represents the shale oil adsorption density per unit area of ​​mineral component x or kerogen surface under the conditions of temperature T, pressure P, and pore diameter r; m (%) x σ represents the mass percentage of mineral component x or kerogen in the total weight of the shale sample; σ represents the specific surface area of ​​the shale sample; l1 represents the starting position of the adsorbed oil density curve in the pores of the mineral or kerogen, l2 represents the ending position of the adsorbed oil density curve in the pores of the mineral or kerogen, l represents the distance of the adsorbed layer from the mineral or kerogen; x represents any type of mineral or kerogen; k is a correction factor.

[0040] According to the present invention, the adsorption layer refers to a layer of shale oil component molecules adsorbed on the surface of minerals or kerogen. The shale oil component distribution density in the adsorption layer is significantly higher than the density of the shale oil components when they are evenly distributed in the pores. The density of the shale oil components evenly distributed in the pores can be obtained by dividing the mass of the shale oil components by the pore volume.

[0041] According to the present invention, l1 represents the starting position of the oil adsorption density curve within the pores of the mineral or kerogen, that is, l1 is the starting position of the shale oil adsorption layer, which is also the position where the shale oil adsorption layer is closest to the mineral or kerogen. l2 represents the ending position of the oil adsorption density curve within the pores of the mineral or kerogen, that is, l2 is the ending position of the shale oil adsorption layer, which is also the position where the shale oil adsorption layer is farthest from the mineral or kerogen. l2-l1 is the thickness of the adsorption layer.

[0042] According to some embodiments of the present invention, in formula (1), Q ao The units of (T, P, r) are mg / m³ 2 ;ρ oil-x The units of (T, P, r) are mg / m³ 3 The unit of σ is m. 2 / g, the unit is m.

[0043] According to some embodiments of the present invention, the actual laboratory measurement results in step (4) are obtained by conducting multi-temperature-level pyrolysis experiments on shale samples under laboratory conditions.

[0044] According to some embodiments of the present invention, the laboratory actual measurement results in step (4) are obtained by conducting a pyrolysis experiment on the shale sample using a pyrolysis apparatus at a constant heating rate, and measuring the pyrolysis hydrocarbon content S obtained by heating the sample from 350°C to 450°C at a rate of 25°C / min and holding the temperature at that rate for 1 min. 2-1 get.

[0045] According to some embodiments of the present invention, in step (4) according to S 2-1 A correction factor was obtained by comparing the ratio of shale adsorbed oil content to that under conditions of 350℃ and 0.1MPa.

[0046] Compared with the prior art, the present invention has the following advantages:

[0047] The molecular simulation method for calculating adsorbed oil content in shale provided by this invention establishes a theoretical calculation model for adsorbed oil content in shale. This model can calculate the adsorbed oil content in shale samples under different mineral compositions and contents, pore sizes, specific surface areas, and temperature and pressure conditions. To a certain extent, it compensates for the limitations of geological-geochemical experiments in testing at the nanoscale pore size of shale, and also addresses the previous neglect of the influence of geological factors such as temperature or pressure on adsorbed oil content. This improves the accuracy and operability of the calculated adsorbed oil content, providing important parameters for evaluating the mobility of shale oil. Furthermore, the established theoretical calculation model is universally applicable and can be applied to different geological conditions even in the absence of samples, which is of great significance for evaluating the potential of overseas shale oil and gas resources. Attached Figure Description

[0048] Figure 1 This is a schematic diagram of the molecular simulation method for calculating the adsorbed oil content in shale according to the present invention.

[0049] Figure 2 The pyrolysis chart used to determine the type of kerogen contained in shale samples in some embodiments of the present invention. Detailed Implementation

[0050] To make the present invention easier to understand, it will be described in detail below with reference to embodiments and accompanying drawings. These embodiments are for illustrative purposes only and should not be considered as limiting the scope of the invention. Unless otherwise specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply.

[0051] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0052] The following description uses montmorillonite as an example, kerogen of type II1, and saturated hydrocarbons as components of shale oil to clearly and completely describe the technical solutions of the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0053] Example 1

[0054] A molecular simulation method for calculating the adsorbed oil content in shale includes the following steps:

[0055] Step 1: Obtain information on the mineral composition, kerogen, and shale oil composition of the shale samples;

[0056] The mineral composition was montmorillonite, accounting for 75% of the shale sample by mass; the kerogen type was II1, accounting for 25% of the shale sample by mass; and the shale oil composition was saturated hydrocarbons.

[0057] Step 2: Select the main minerals and kerogen types in shale, select representative molecules in shale oil components, and establish molecular models for each;

[0058] The shale mineral composition was selected from calcium montmorillonite, the kerogen was selected from type II1, and the shale oil composition was selected from C. 19 H 40 A molecular model was built using Materials Studio software.

[0059] Step 3: Molecular simulations were performed on the shale minerals, kerogen, and shale oil components under different temperature, pressure, and pore conditions to obtain the surface shale oil adsorption density of the shale minerals and kerogen, respectively.

[0060] The shale mineral-kerogen-shale oil model was simulated using Materials Studio software. The force field type was COMPASSII, the simulation time was set to 1 ns, and the van der Waals radius was 1.25 nm. Molecular simulations of the mineral-kerogen-shale oil model were performed under the actual formation temperature and pressure conditions (85℃, 30 MPa) of the Lucaogou Formation in the Jimsar Depression of the Junggar Basin to obtain the oil adsorption density on the mineral and kerogen surfaces.

[0061] Step 4: Establish a model relating the amount of adsorbed oil to mineral composition, kerogen content, and specific surface area, and correct the theoretical calculation model using multi-temperature-level pyrolysis experimental results to calculate the adsorbed oil content of the shale sample.

[0062] Based on the adsorption capacity of shale oil under different minerals and kerogen in shale at 85℃ and 30MPa, a model was established to relate the amount of adsorbed oil to the content of mineral components, kerogen content, pore size, and specific surface area. Multiple shale samples were subjected to multi-temperature-level pyrolysis experiments under laboratory conditions to obtain the amount of adsorbed oil. By comparing the theoretical calculation model with the experimentally tested adsorbed oil data, a correction factor k was obtained, and the adsorbed oil content of the shale samples was calculated.

[0063] The results showed that, under the conditions of 85℃ temperature, 30MPa pressure, and 10nm pore diameter, the average adsorption density of kerogen for shale oil was 2.5×10⁻⁶. 9 mg / m 3 The thickness of the adsorption layer (l2-l1) is 3.2×10⁻⁶. -9 The average adsorption density of montmorillonite for shale oil is 0.8 × 10⁻⁶ m. 9 mg / m 3 The thickness of the adsorption layer (l2-l1) is 0.2×10⁻⁶. -9 m, specific surface area is 300 m² 2 / g. The correction factor k is set to 0.001, and the shale adsorbed oil content is 6.36 mg / g.

[0064] It should be noted that the embodiments described above are only for explaining the present invention and do not constitute any limitation on the present invention. The present invention has been described with reference to typical embodiments, but it should be understood that the words used therein are descriptive and explanatory terms, not limiting terms. Modifications can be made to the present invention within the scope of the claims, and revisions can be made to the present invention without departing from the scope and spirit of the present invention. Although the present invention described herein relates to specific methods, materials, and embodiments, it does not mean that the present invention is limited to the specific examples disclosed herein; on the contrary, the present invention can be extended to all other methods and applications with the same function.

Claims

1. A molecular simulation method for calculating the adsorbed oil content in shale, comprising the following steps: (1) Obtain information on mineral composition, kerogen and shale oil composition, specific surface area and pore structure of different shale samples; (2) Select representative indicators from the mineral composition information, kerogen information, shale oil composition information, specific surface area and pore structure information of the obtained shale samples respectively, and establish molecular models to simulate the corresponding shale samples based on the representative indicators; (3) Using the molecular model established in step (2), molecular dynamics simulations were performed on different shale samples under different temperatures, pressures, specific surface areas and pore structures to obtain the shale oil adsorption density of shale samples under different temperatures, pressures, specific surface areas and pore structures, and a model was established to establish the relationship between the amount of adsorbed oil and the mineral composition, kerogen and specific surface area of ​​the shale samples. (4) Correct the relationship model obtained in step (3) based on the actual laboratory measurement results to obtain the relationship between the correction factor and the shale adsorbed oil amount calculation model, and calculate the shale adsorbed oil amount. The actual laboratory measurement results mentioned in step (4) are obtained by conducting multi-temperature-stage pyrolysis experiments on shale samples under laboratory conditions. This includes conducting pyrolysis experiments on the shale samples using a pyrolysis apparatus at a constant heating rate, heating the temperature from 350℃ to 450℃ at a rate of 25℃ / min and holding it at that temperature for 1 min to obtain the pyrolysis hydrocarbon content S. 2-1 Obtain; Correction factor k For S 2-1 The ratio of shale adsorbed oil content to that under conditions of 350℃ and 0.1MPa.

2. The molecular simulation method according to claim 1, characterized in that, The mineral component information includes the specific types and contents of the mineral components, and / or the kerogen information includes the type and contents of the kerogen, and / or the shale oil component information includes the component type of the shale oil, the compounds it contains, and the contents of the component type and the contents of the compounds it contains. And / or the specific surface area and pore structure information includes the specific surface area size and pore size of the shale sample.

3. The molecular simulation method according to claim 1 or 2, characterized in that, In step (1), the mineral composition information contained in the shale sample is obtained by performing whole-rock X-ray diffraction analysis on the shale sample; And / or by performing group component separation analysis on the chloroform bitumen extract of fresh shale samples to obtain information on the shale oil components contained in the shale samples, by performing TOC testing on the chloroform-extracted shale samples to obtain the kerogen content, and by performing pyrolysis analysis on the chloroform-extracted shale samples to obtain the pyrolysis hydrocarbon content S2, CO2 content S3, and peak pyrolysis hydrocarbon temperature T at 300-500℃. max The data were used to determine the type of kerogen contained in the shale samples based on the pyrolysis charts. And / or obtain the pore structure and specific surface area information of the shale sample using at least one of nuclear magnetic resonance, nitrogen adsorption and mercury porosimetry.

4. The molecular simulation method according to claim 1 or 2, characterized in that, In step (1), the oil produced from the shale reservoir corresponding to the shale sample is analyzed by group component separation to obtain the shale oil component information contained in the shale sample.

5. The molecular simulation method according to claim 1 or 2, characterized in that, In step (2), the representative indicators of the mineral composition information include the crystal structure and content of all constituent minerals contained in the shale sample or the crystal structure and content of the main constituent minerals; and / or the representative indicators of the kerogen information include the most typical kerogen type contained in the shale sample; and / or the representative indicators of the shale oil composition information include the representative molecules of the main component types in the shale oil and the content of the main component types; and / or the representative indicators of the specific surface area and pore structure information include the specific surface area and pore size of the shale sample.

6. The molecular simulation method according to claim 5, characterized in that, And / or the main component types in the shale oil include saturated hydrocarbons, aromatic hydrocarbons, non-hydrocarbons, and asphaltenes.

7. The molecular simulation method according to claim 5, characterized in that, The step (2) of establishing a molecular model simulating the shale sample based on the representative indicators includes: establishing a molecular model based on the crystal structure of the minerals that make up the shale sample and / or the kerogen type; and / or the content ratio of the main component types in the shale oil; and / or the pore size of the shale sample. Specifically, establishing a molecular model based on the content ratio of the main component types in shale oil means that the total content ratio of representative molecules in the main component types is consistent with the content ratio of the main component types in the shale sample; establishing a molecular model based on the pore size of the shale sample means setting different pore diameters in the model according to the pore size of the shale sample.

8. The molecular simulation method according to claim 1 or 2, characterized in that, The molecular dynamics simulation described in step (3) is achieved by a method including the following steps: setting the force field type for the molecular model of shale samples with different mineral compositions, kerogen types, specific surface areas and pore structures and shale oil compositions, and applying simulated temperature and simulated pressure conditions to perform molecular dynamics simulations under different temperature, pressure, specific surface area and pore structure conditions.

9. The molecular simulation method according to claim 1 or 2, characterized in that, In step (3), the relationship model between the amount of adsorbed oil and the mineral composition, kerogen, specific surface area and porosity of the shale sample is established by using the shale oil adsorption density of the shale sample and combining the proportion of mineral composition and kerogen in the shale sample and the specific surface area of ​​the shale sample to establish the relationship model between the amount of adsorbed oil in the shale sample and the content of mineral composition, kerogen content and specific surface area.

10. The molecular simulation method according to claim 1 or 2, characterized in that, In step (4), the calculation model relationship for the amount of oil adsorbed by shale is shown in equation (1) below: （1） In equation (1), Q ao (T, P, r) For temperature T, pressure P, and pore diameter r Oil adsorption per unit area of ​​shale under certain conditions; ρ oil-x (T, P, r) For temperature T, pressure P, and pore diameter r Under certain conditions, the adsorption density of shale oil on the surface of mineral component x or kerogen; m （%） x x represents the mass percentage of the mineral component or kerogen in the total weight of the shale sample; σ represents the specific surface area of ​​the shale sample. l 1 indicates the starting position of the adsorbed oil density curve within the pores of the mineral or kerogen. l 2 indicates the cutoff position of the adsorbed oil density curve within the pores of the mineral or kerogen; l The distance between the adsorption layer and the mineral component or kerogen is indicated. The adsorption layer is a layer of shale oil components adsorbed on the surface of the mineral component or kerogen. x represents any mineral or kerogen. k is a correction factor.

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