Evaluation method and apparatus for dynamic diffusion of natural hydrogen in rock pores, and device

Abstract

The present application provides an evaluation method and apparatus for dynamic diffusion of natural hydrogen in rock pores, and a device. The method comprises: performing hydrogen adsorption simulation calculation at a target pressure and a target temperature on the basis of a pre-constructed pore model of a rock to be evaluated, and determining the average number of hydrogen molecules adsorbed in pores when hydrogen reaches saturation at the target temperature and the target pressure; on the basis of lithological parameters of said rock, the average number of hydrogen molecules adsorbed in the pores at the target temperature and the target pressure, the target pressure, and the target temperature, determining the content of natural hydrogen in the rock pores; adding a preset gas into the pore model, and when the pore model is saturated at the target pressure and the target temperature, determining the loss content of natural hydrogen, and determining a diffusion coefficient of natural hydrogen; and determining a diffusion evaluation parameter on the basis of the content of natural hydrogen in the rock pores, the loss content of natural hydrogen, and the diffusion coefficient of natural hydrogen. The present application can improve the accuracy of evaluation for diffusion of natural hydrogen.

Description

Evaluation methods, apparatus and equipment for dynamic diffusion of natural hydrogen in rock pores

[0001] This patent application claims priority to Chinese Patent Application No. CN202410786591.3, filed on June 18, 2024. The disclosure of the earlier application is incorporated herein by reference in its entirety. Technical Field

[0002] This application relates to the field of oil and gas exploration technology, and in particular to a method, apparatus and equipment for evaluating the dynamic diffusion of natural hydrogen in rock pores. Background Technology

[0003] The gas diffusion coefficient is a physical quantity that describes the rate at which gas molecules diffuse through a unit area per unit time. It measures the ability and rate of gas molecule diffusion and is one of the important parameters describing the gas diffusion process. The gas diffusion coefficient is related to several factors, such as the mass of the gas molecules, temperature, pressure, molecular size, and the properties of the diffusion environment. Generally, the larger the mass of the gas molecules, the smaller the diffusion coefficient; the higher the temperature, the larger the diffusion coefficient; and the higher the pressure, the larger the diffusion coefficient.

[0004] The study of hydrogen diffusion coefficients can deepen our understanding of hydrogen transport and diffusion processes from a kinetic perspective, solve practical problems in future natural hydrogen exploration, and contribute to the study of natural hydrogen enrichment areas. Currently, the most commonly used kinetic models for calculating and evaluating gas diffusion coefficients are those under isothermal and isobaric conditions. The variation of gas diffusion coefficients is evaluated by establishing experimental conditions under different temperatures and pressures.

[0005] However, based on data obtained from existing experimental methods, the constructed gas diffusion coefficient model has many errors in quantitatively evaluating the dynamic diffusion process of natural hydrogen, and cannot accurately quantitatively evaluate the diffusion process of natural hydrogen. Technical issues

[0006] This application provides a method, apparatus, and equipment for evaluating the dynamic diffusion of natural hydrogen in rock pores, in order to solve the problem that current evaluation methods for the diffusion process of natural hydrogen have many errors and are inaccurate. Technical solutions

[0007] In a first aspect, embodiments of this application provide a method for evaluating the dynamic diffusion of natural hydrogen in rock pores, including:

[0008] Hydrogen adsorption simulation calculations were performed based on a pre-built pore model of the rock to be evaluated under target pressure and target temperature to determine the average number of hydrogen molecules adsorbed in the pores when hydrogen is saturated under the target temperature and pressure.

[0009] Based on the lithological parameters of the rock to be evaluated, the average number of hydrogen molecules adsorbed in the pores under the target temperature and pressure, the target pressure and the target temperature, the content of natural hydrogen in the rock pores is determined; the lithological parameters include the pore diameter, pore type influence coefficient and pore specific surface area of ​​the rock to be evaluated.

[0010] A preset gas is added to the pore model, and when the pore model is saturated at the target pressure and temperature, the loss content of natural hydrogen and the diffusion coefficient of natural hydrogen are determined; wherein the preset gas is one or more gases other than hydrogen; and

[0011] Based on the content of natural hydrogen in rock pores, the loss of natural hydrogen, and the diffusion coefficient of natural hydrogen, diffusion evaluation parameters are determined.

[0012] In one possible implementation, the process of constructing the pore model is as follows:

[0013] Based on the target test data of the rock to be evaluated, the full pore size distribution and pore throat diameter distribution of the rock were determined; the target test data included scanning electron microscopy, high-pressure pump, and carbon dioxide / nitrogen adsorption test data; and

[0014] Based on the full pore size distribution, pore throat diameter distribution, and mineral composition of the rock to be evaluated, a pore model of the rock to be evaluated is constructed.

[0015] In one possible implementation, the content of natural hydrogen in the rock pores is determined based on the lithological parameters of the rock to be evaluated, the average number of hydrogen molecules adsorbed in the pores under the target temperature and pressure, the target pressure, and the target temperature, including:

[0016] By inputting lithological parameters, the average number of hydrogen molecules adsorbed in the pores under the target temperature and pressure, the target pressure, and the target temperature into a pre-constructed ideal model for predicting the content of natural hydrogen, the content of natural hydrogen in the rock pores is obtained.

[0017] Among them, the ideal model for predicting natural hydrogen content V 1H2 for:

[0018] ;

[0019] Among them, K i Let be the influence coefficient of the i-th rock pore type, n be the total number of rock pore type influence coefficients, T be the formation temperature, P be the formation pressure, D be the pore diameter, S be the pore specific surface area, and V be the pore diameter. m N is the gas volume under standard conditions, and N is the number of hydrogen molecules. A Let be Avogadro's constant, and a, b, c, and d be the fitting constants obtained based on the training samples.

[0020] In one possible implementation, a preset gas is added to the pore model, and when the pore model is saturated at the target pressure and temperature, the loss of natural hydrogen is determined, including:

[0021] Add a preset gas to the pore model, and determine the number of hydrogen molecules diffusing out of the pores when the pore model is saturated at the target pressure and temperature; and

[0022] The loss of natural hydrogen is determined based on the number of hydrogen molecules diffusing out of the pores and a pre-defined hydrogen loss model; the pre-defined hydrogen loss model is determined based on the number of hydrogen molecules diffusing out of the pores and the gas volume under standard conditions.

[0023] In one possible implementation, a hydrogen loss model is pre-defined. for:

[0024] ;

[0025] Among them, V m N is the gas volume under standard conditions, and N is the number of hydrogen molecules diffusing out of the pores. A is Avogadro's constant.

[0026] In one possible implementation, determining the diffusion coefficient of natural hydrogen includes:

[0027] The diffusion coefficient of natural hydrogen is determined based on a pre-defined diffusion coefficient correction model.

[0028] Among them, the diffusion coefficient correction model DT H2 for:

[0029] ;

[0030] Among them, K i Let denoted as the influence coefficient of the i-th rock pore type, n be the total number of rock pore type influence coefficients, T be the formation temperature, P be the formation pressure, D be the pore diameter, and R be the pore throat diameter of the rock to be evaluated. DT j Let be the diffusion coefficient of any preset gas in the pore, m be the number of preset gas types, and h, r, k, e, and x be the fitting constants obtained based on the training samples.

[0031] In one possible implementation, diffusion evaluation parameters are determined based on the content of natural hydrogen in rock pores, the loss of natural hydrogen, and the diffusion coefficient of natural hydrogen, including:

[0032] The content of natural hydrogen in the rock pores, the loss of natural hydrogen, and the diffusion coefficient of natural hydrogen are input into a pre-constructed diffusion evaluation model to obtain the diffusion coefficient of natural hydrogen in the pores of the rock to be evaluated.

[0033] The diffusion evaluation model TC is as follows:

[0034] ;

[0035] The diffusion coefficient of natural hydrogen is given. This represents the loss of natural hydrogen. This represents the amount of natural hydrogen gas in the pores of the rock.

[0036] Secondly, embodiments of this application provide an evaluation device for the dynamic diffusion of natural hydrogen in rock pores, comprising:

[0037] The first determination module is used to perform hydrogen adsorption simulation calculations based on a pre-built pore model of the rock to be evaluated under target pressure and target temperature, and to determine the average number of hydrogen molecules adsorbed in the pores when hydrogen is saturated under the target temperature and pressure.

[0038] The second determination module is used to determine the content of natural hydrogen in the pores of the rock based on the lithological parameters of the rock to be evaluated, the average number of hydrogen molecules adsorbed in the pores under the target temperature and pressure, the target pressure, and the target temperature; the lithological parameters include the pore diameter, pore type influence coefficient, and pore specific surface area of ​​the rock to be evaluated.

[0039] The third determining module is used to determine the loss content of natural hydrogen and the diffusion coefficient of natural hydrogen when the pore model is saturated at the target pressure and temperature and a preset gas is added to the pore model; wherein the preset gas is one or more gases other than hydrogen; and

[0040] The fourth determination module is used to determine diffusion evaluation parameters based on the content of natural hydrogen in rock pores, the loss of natural hydrogen, and the diffusion coefficient of natural hydrogen.

[0041] Thirdly, embodiments of this application provide an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the steps of the method as described in the first aspect or any possible implementation of the first aspect above.

[0042] Fourthly, embodiments of this application provide a computer-readable storage medium storing a computer program that, when executed by a processor, implements the steps of the method as described in the first aspect or any possible implementation of the first aspect. Beneficial effects

[0043] This application provides a method, apparatus, and device for evaluating the dynamic diffusion of natural hydrogen in rock pores. First, hydrogen adsorption simulation calculations are performed based on a pre-constructed pore model of the rock to be evaluated under target pressure and temperature to determine the average number of hydrogen molecules adsorbed within the pores when hydrogen is saturated at the target temperature and pressure. Next, based on the lithological parameters of the rock to be evaluated, the average number of hydrogen molecules adsorbed within the pores at the target temperature and pressure, and the target pressure and temperature, the content of natural hydrogen in the rock pores is determined. Then, a preset gas is added to the pore model, and when the pore model is saturated at the target pressure and temperature, the loss of natural hydrogen is determined, and the diffusion coefficient of natural hydrogen is also determined. Finally, based on the content of natural hydrogen in the rock pores, the loss of natural hydrogen, and the diffusion coefficient of natural hydrogen, diffusion evaluation parameters are determined. By establishing a pore model to conduct molecular dynamics simulations under geological conditions, and based on the established pore model, the content of natural hydrogen in rock pores, the loss of natural hydrogen, and the diffusion coefficient of natural hydrogen were determined, thereby realizing a quantitative evaluation of the dynamic diffusion of natural hydrogen in rock pores, and the evaluation results are more accurate. Attached Figure Description

[0044] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0045] Figure 1 is a flowchart of the implementation of the evaluation method for dynamic diffusion of natural hydrogen in rock pores provided in the embodiments of this application;

[0046] Figure 2 is a flowchart of the evaluation method for dynamic diffusion of natural hydrogen in rock pores provided in the embodiments of this application;

[0047] Figure 3 is a schematic diagram of the pore model construction provided in the embodiments of this application;

[0048] Figure 4 is a schematic diagram of the evaluation range of dynamic diffusion of natural hydrogen provided in the embodiments of this application;

[0049] Figure 5 is a schematic diagram of the structure of the evaluation device for dynamic diffusion of natural hydrogen in rock pores provided in the embodiments of this application;

[0050] Figure 6 is a schematic diagram of an electronic device provided in an embodiment of this application. Embodiments of the present invention

[0051] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of this application. However, those skilled in the art will understand that this application may also be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods have been omitted so as not to obscure the description of this application with unnecessary detail.

[0052] To make the objectives, technical solutions, and advantages of this application clearer, the following description will be provided in conjunction with the accompanying drawings and specific embodiments.

[0053] The migration of natural hydrogen in the geological environment is a random diffusion process, the intensity of which is influenced by the coupling effects of temperature, pressure, and reservoir medium in the underground environment. Although existing studies have measured the hydrogen infiltration concentration in shallow soil within the "fairy circle," the diffusion capacity of natural hydrogen changes significantly during its migration from deeper layers. Therefore, methods for quantitatively evaluating the dynamic diffusion of natural hydrogen in deeper layers, limited to the "fairy circle," cannot comprehensively and accurately characterize the amount of natural hydrogen lost. While there are numerous studies and experiments on the diffusion coefficient, they cannot accurately reproduce the dynamic changes in the diffusion coefficient during the natural hydrogen diffusion process, and the mathematical relationship between the diffusion coefficient (a parameter measuring gas mobility) and the amount of natural hydrogen lost is not properly understood. Therefore, a comprehensive and accurate evaluation index for the quantitative assessment of the dynamic diffusion of natural hydrogen has not been proposed, failing to meet most of the evaluation needs for future natural hydrogen exploration and development.

[0054] To address the problems of the prior art, embodiments of this application provide a method, apparatus, and device for evaluating the dynamic diffusion of natural hydrogen in rock pores. The method for evaluating the dynamic diffusion of natural hydrogen in rock pores provided in this application embodiment will be described first below.

[0055] Referring to Figures 1 and 2, which respectively illustrate the implementation flowchart and flow chart of the evaluation method for dynamic diffusion of natural hydrogen in rock pores provided in the embodiments of this application, detailed below:

[0056] S110. Perform hydrogen adsorption simulation calculations based on a pre-constructed pore model of the rock to be evaluated under target pressure and target temperature to determine the average number of hydrogen molecules adsorbed in the pores when hydrogen is saturated at the target temperature and pressure. Target temperature and pressure are abbreviations for target temperature and target pressure.

[0057] In this embodiment, it is necessary to first construct a pore model of the rock to be evaluated, and then perform molecular dynamics calculations based on the pore model at different target temperatures and target pressures.

[0058] In some embodiments, the pore model of the rock to be evaluated can be determined based on the core sample of the target layer. The specific process for determination is as follows:

[0059] As shown in Figure 2, the full pore size distribution and pore throat diameter distribution of the rock to be evaluated can be determined first, based on the target test data, such as scanning electron microscopy, high-pressure pump, and carbon dioxide / nitrogen adsorption test data. Figure 3I shows the full pore size distribution of three different rock cores, and Figure 3II shows the pore throat diameter distribution of three different rock cores. Scanning electron microscopy (SEM) is widely used in microscopic studies in life sciences, physics, chemistry, earth sciences, and materials science. In earth sciences, it includes crystallography, mineralogy, ore deposit geology, sedimentology, astrogeology, petroleum geology, engineering geology, and structural geology. High-pressure pump is a high-pressure pump.

[0060] Then, based on the full pore size distribution, pore throat diameter distribution, and mineral composition of the rock to be evaluated obtained above, a pore model of the rock to be evaluated is constructed. Figure 3 shows the pore models of three different rocks constructed (III).

[0061] Based on the constructed pore model of the rock to be evaluated, hydrogen adsorption simulation calculations were performed at target pressure and temperature. The adsorption simulation simulated the adsorption of hydrogen molecules within the pore model by varying the number of hydrogen molecules in the model. Specifically, hydrogen molecules were randomly created or deleted at arbitrary positions within the pore model to maintain the input temperature and pressure conditions until the pore model reached equilibrium with hydrogen saturation, at which point the total energy within the system was at its lowest. This determined the average number of hydrogen molecules adsorbed within the pores at the target temperature and pressure for hydrogen saturation.

[0062] S120. Based on the lithological parameters of the rock to be evaluated, the average number of hydrogen molecules adsorbed in the pores under the target temperature and pressure, the target pressure, and the target temperature, determine the content of natural hydrogen in the rock pores.

[0063] The content of naturally occurring hydrogen in rock pores is affected by many factors such as temperature, pressure, and pore type. Therefore, accurately determining the content of naturally occurring hydrogen in rock pores is necessary when evaluating the diffusion of naturally occurring hydrogen. The specific determination process is as follows:

[0064] By inputting lithological parameters, the average number of hydrogen molecules adsorbed in the pores under the target temperature and pressure, the target pressure, and the target temperature into a pre-constructed ideal model for predicting the content of natural hydrogen, the content of natural hydrogen in the rock pores is obtained.

[0065] Lithological parameters may include the pore diameter, pore type influence coefficient, and pore specific surface area of ​​the rock to be evaluated.

[0066] The ideal model for predicting natural hydrogen content is a linear relationship between the hydrogen content in pores and influencing factors, specifically:

[0067] Ideal model for predicting natural hydrogen content V 1H2 for:

[0068] ;

[0069] Among them, K i Let be the influence coefficient of the i-th rock pore type, n be the total number of rock pore type influence coefficients, T be the formation temperature, P be the formation pressure, D be the pore diameter, S be the pore specific surface area, and V be the pore diameter. m N is the gas volume under standard conditions, and N is the number of hydrogen molecules. A Let be Avogadro's constant, and a, b, c, and d be the fitting constants obtained based on the training samples.

[0070] It should be noted that if the rock being evaluated is a single type of rock, there is only one rock pore type influence coefficient. However, if the rock being evaluated is a pieced-together rock, that is, two different types of rock, there are two different rock pore type influence coefficients.

[0071] a, b, c, and d were determined by fitting historical simulation experimental data and collected data, that is, by fitting data from a large number of training samples.

[0072] For pieced-together rocks, the content of natural hydrogen in the rock pores is:

[0073] .

[0074] S130. Add a preset gas to the pore model, and when the pore model is saturated at the target pressure and target temperature, determine the loss content of natural hydrogen and the diffusion coefficient of natural hydrogen.

[0075] Natural hydrogen gas remains the primary measurement target, and a preset gas is added to the pore model. This preset gas can be methane, carbon dioxide, nitrogen, helium, etc. When the pore model saturates at the target pressure and temperature, the number of hydrogen molecules diffusing out of the pores needs to be determined first.

[0076] The method for calculating the number of hydrogen molecules diffusing out of the pores is also based on adsorption simulation calculations. This involves changing the number of hydrogen molecules in the pore model to simulate their adsorption. Specifically, hydrogen molecules are randomly created or deleted at arbitrary positions within the pore model to maintain the input temperature and pressure conditions during the simulation, until the pore model reaches equilibrium with hydrogen saturation. At equilibrium, the total energy within the system is at its lowest. This determines the number of hydrogen molecules adsorbed in the pores after adding a preset gas at the target temperature and pressure. The difference between the average number of hydrogen molecules adsorbed in the pores when hydrogen is saturated at the target temperature and pressure and the number of hydrogen molecules adsorbed in the pores after adding the preset gas at the target temperature and pressure can be used to determine the number of hydrogen molecules diffusing out of the pores.

[0077] Once the number of hydrogen molecules diffusing out of the pores is determined, the loss of natural hydrogen can be determined based on the number of hydrogen molecules diffusing out of the pores and a preset hydrogen loss model.

[0078] The preset hydrogen loss model is determined based on the number of hydrogen molecules diffusing out of the pores and the gas volume under standard conditions.

[0079] In some embodiments, a preset hydrogen loss model is used. for:

[0080] ;

[0081] Among them, V m The volume of gas under standard conditions is 22.4 mol·L⁻¹. -1 N is the number of hydrogen molecules that diffuse out of the pores. A is Avogadro's constant.

[0082] The diffusion coefficient of natural hydrogen is determined based on a pre-defined diffusion coefficient correction model.

[0083] Among them, the diffusion coefficient correction model DT H2 for:

[0084] ;

[0085] Among them, K i Let denoted as the influence coefficient of the i-th rock pore type, n be the total number of rock pore type influence coefficients, T be the formation temperature, P be the formation pressure, D be the pore diameter, and R be the pore throat diameter of the rock to be evaluated. DT j Let be the diffusion coefficient of any preset gas in the pore, m be the number of preset gas types, and h, r, k, e, and x be the fitting constants obtained based on the training samples.

[0086] It should be noted that if the rock being evaluated is a single type of rock, there is only one rock pore type influence coefficient. However, if the rock being evaluated is a pieced-together rock, that is, two different types of rock, there are two different rock pore type influence coefficients.

[0087] h, r, k, e, and x are also determined by fitting historical simulation experimental data and collected data, that is, by fitting from a large number of training samples.

[0088] In some embodiments, the diffusion coefficient DT of any predetermined gas in the pores j The process of determining is as follows:

[0089] Molecular dynamics simulations were performed on a pore model of saturated hydrogen gas based on actual underground temperature and pressure conditions. The molecular dynamics simulations were based on Newton's laws of mechanics.

[0090] F = ma = dp / dt;

[0091] Where m is the mass of the particle; a = d 2 r / dt 2 F is the particle's acceleration; F is the force applied to the particle; and p is the particle's momentum.

[0092] By integrating the above equation over time, the velocity and position of the particle after time t are predicted, thus obtaining the particle's potential energy after time t. Then, the stress state and acceleration of the particle are calculated using the equation. Repeating the above process yields the dynamic information of the particles in the system at different time steps (such as mean squared displacement (MSD)). Therefore, the mean squared displacement (MSD) of any preset gas during diffusion can be directly obtained from molecular dynamics calculations. A mean squared displacement-time function relationship graph can be established, and according to Einstein's energy equation, 1 / 6 of the slope of the mean squared displacement-time function relationship graph is taken as the diffusion coefficient DTothers of any gas.

[0093] ;

[0094] Where MSD is the mean square displacement of any gas during the diffusion process; t is time.

[0095] The diffusion coefficient DT for each preset gas can be determined using the above process. j .

[0096] S140. Based on the content of natural hydrogen in rock pores, the loss of natural hydrogen, and the diffusion coefficient of natural hydrogen, determine the diffusion evaluation parameters.

[0097] The content of natural hydrogen in the rock pores, the loss of natural hydrogen, and the diffusion coefficient of natural hydrogen are input into a pre-constructed diffusion evaluation model to obtain the diffusion coefficient of natural hydrogen in the pores of the rock to be evaluated.

[0098] The diffusion evaluation model TC is as follows:

[0099] ;

[0100] The diffusion coefficient of natural hydrogen is given. This represents the loss of natural hydrogen. This represents the amount of natural hydrogen gas in the pores of the rock.

[0101] The diffusion dynamics of natural hydrogen are evaluated based on the value of TC, as shown in the table below:

[0102] Quantitative evaluation parameters for natural hydrogen diffusion: TC < 1 = 1 > 1 indicates strong natural hydrogen diffusion and weak dynamic equilibrium.

[0103] As shown in Figure 4, when TC=1, the diffusion coefficient is moderate, and the hydrogen loss content is dynamically balanced with the hydrogen content within the rock pores. When TC<1, the DT... H2 The DT value is relatively large, and the degree of hydrogen diffusion is relatively enhanced. When TC > 1, the DT value is relatively large. H2 The hydrogen loss is relatively small, and the degree of hydrogen diffusion is relatively weak. Alternatively, based on the known natural hydrogen content in any reservoir (field analysis or well logging data), the corresponding reservoir hydrogen loss content can be calculated and predicted using the evaluation parameter TC.

[0104] This application, based on a constructed pore model, reverts to the essence of hydrogen migration as the random diffusion of hydrogen molecules, unaffected by other external characterizations or human factors, resulting in more scientific and objective evaluation results. Furthermore, this application determines diffusion evaluation parameters based on the content of natural hydrogen in rock pores, the loss of natural hydrogen, and the diffusion coefficient of natural hydrogen, achieving a continuous numerical characterization of "initial content - diffusion coefficient - loss content." This aligns with the dynamic accumulation and hydrocarbon reservoir characteristics of natural hydrogen migration under actual geological conditions, possessing practical guiding significance and resulting in more accurate evaluation results.

[0105] The method for evaluating the dynamic diffusion of natural hydrogen in rock pores provided in this application firstly performs hydrogen adsorption simulation calculations based on a pre-constructed pore model of the rock to be evaluated under target pressure and temperature to determine the average number of hydrogen molecules adsorbed in the pores when hydrogen is saturated at the target temperature and pressure. Next, based on the lithological parameters of the rock to be evaluated, the average number of hydrogen molecules adsorbed in the pores under the target temperature and pressure, and the target pressure and temperature, the content of natural hydrogen in the rock pores is determined. Then, a preset gas is added to the pore model, and when the pore model is saturated at the target pressure and temperature, the loss of natural hydrogen is determined, and the diffusion coefficient of natural hydrogen is also determined. Finally, based on the content, loss, and diffusion coefficient of natural hydrogen in the rock pores, diffusion evaluation parameters are determined. By establishing a pore model to perform molecular dynamics simulations under geological conditions, and determining the content, loss, and diffusion coefficient of natural hydrogen in the rock pores based on the established pore model, a quantitative evaluation of the dynamic diffusion of natural hydrogen in rock pores is achieved, and the evaluation results are more accurate.

[0106] It should be understood that the sequence number of each step in the above embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0107] Based on the evaluation method for the dynamic diffusion of natural hydrogen in rock pores provided in the above embodiments, this application also provides a specific implementation of an evaluation device for the dynamic diffusion of natural hydrogen in rock pores applied to this evaluation method. Please refer to the following embodiments.

[0108] As shown in Figure 5, this application embodiment provides an evaluation device 500 for the dynamic diffusion of natural hydrogen in rock pores. The device includes:

[0109] The first determining module 510 is used to perform hydrogen adsorption simulation calculations based on a pre-built pore model of the rock to be evaluated under target pressure and target temperature, and to determine the average number of hydrogen molecules adsorbed in the pores when hydrogen is saturated under the target temperature and pressure.

[0110] The second determining module 520 is used to determine the content of natural hydrogen in the pores of the rock based on the lithological parameters of the rock to be evaluated, the average number of hydrogen molecules adsorbed in the pores under the target temperature and pressure, the target pressure, and the target temperature; the lithological parameters include the pore diameter, pore type influence coefficient, and pore specific surface area of ​​the rock to be evaluated.

[0111] The third determining module 530 is used to determine the loss content of natural hydrogen and the diffusion coefficient of natural hydrogen when the pore model is saturated at the target pressure and target temperature and a preset gas is added to the pore model; wherein the preset gas is one or more gases other than hydrogen; and

[0112] The fourth determination module 540 is used to determine diffusion evaluation parameters based on the content of natural hydrogen in rock pores, the loss of natural hydrogen, and the diffusion coefficient of natural hydrogen.

[0113] In one possible implementation, the first determining module 510 is used to determine the full pore size distribution and pore throat diameter distribution of the rock to be evaluated based on the target test data of the rock to be evaluated; wherein the target test data includes scanning electron microscopy, high pressure pump, and carbon dioxide / nitrogen adsorption test data;

[0114] Based on the full pore size distribution, pore throat diameter distribution, and mineral composition of the rock to be evaluated, a pore model of the rock to be evaluated is constructed.

[0115] In one possible implementation, the second determining module 520 is used to input lithological parameters, the average number of hydrogen molecules adsorbed in the pores under the target temperature and pressure, the target pressure and the target temperature into a pre-constructed ideal model for predicting the content of natural hydrogen in the rock pores, so as to obtain the content of natural hydrogen in the rock pores.

[0116] Among them, the ideal model for predicting natural hydrogen content V 1H2 for:

[0117] ;

[0118] Among them, K i Let be the influence coefficient of the i-th rock pore type, n be the total number of rock pore type influence coefficients, T be the formation temperature, P be the formation pressure, D be the pore diameter, S be the pore specific surface area, and V be the pore diameter. m N is the gas volume under standard conditions, and N is the number of hydrogen molecules. A Let be Avogadro's constant, and a, b, c, and d be the fitting constants obtained based on the training samples.

[0119] In one possible implementation, the third determining module 530 is used to add a preset gas to the pore model and, when the pore model is saturated at the target pressure and target temperature, determine the number of hydrogen molecules diffusing out of the pores; and

[0120] The loss of natural hydrogen is determined based on the number of hydrogen molecules diffusing out of the pores and a pre-defined hydrogen loss model; the pre-defined hydrogen loss model is determined based on the number of hydrogen molecules diffusing out of the pores and the gas volume under standard conditions.

[0121] In one possible implementation, a hydrogen loss model is pre-defined. for:

[0122] ;

[0123] Among them, V m N is the gas volume under standard conditions, and N is the number of hydrogen molecules diffusing out of the pores. A is Avogadro's constant.

[0124] In one possible implementation, the third determining module 530 is used to determine the diffusion coefficient of natural hydrogen based on a preset diffusion coefficient correction model.

[0125] Among them, the diffusion coefficient correction model DT H2 for:

[0126] ;

[0127] Among them, K i Let denoted as the influence coefficient of the i-th rock pore type, n be the total number of rock pore type influence coefficients, T be the formation temperature, P be the formation pressure, D be the pore diameter, and R be the pore throat diameter of the rock to be evaluated. DT j Let be the diffusion coefficient of any preset gas in the pore, m be the number of preset gas types, and h, r, k, e, and x be the fitting constants obtained based on the training samples.

[0128] In one possible implementation, the fourth determining module 540 is used to input the content of natural hydrogen in the rock pores, the loss of natural hydrogen, and the diffusion coefficient of natural hydrogen into a pre-constructed diffusion evaluation model to obtain the diffusion coefficient of natural hydrogen in the pores of the rock to be evaluated.

[0129] The diffusion evaluation model TC is as follows:

[0130] ;

[0131] The diffusion coefficient of natural hydrogen is given. This represents the loss of natural hydrogen. This represents the amount of natural hydrogen gas in the pores of the rock.

[0132] Figure 6 is a schematic diagram of an electronic device provided in an embodiment of this application. As shown in Figure 6, the electronic device 6 of this embodiment includes: a processor 60, a memory 61, and a computer program 62 stored in the memory 61 and executable on the processor 60. When the processor 60 executes the computer program 62, it implements the steps in the above-described evaluation method embodiments for the dynamic diffusion of natural hydrogen in rock pores, such as steps S110 to S140 shown in Figure 1. Alternatively, when the processor 60 executes the computer program 62, it implements the functions of each module in the above-described device embodiments, such as the functions of modules 510 to 540 shown in Figure 5.

[0133] For example, the computer program 62 may be divided into one or more modules, which are stored in the memory 61 and executed by the processor 60 to complete this application. The one or more modules may be a series of computer program instruction segments capable of performing a specific function, which describe the execution process of the computer program 62 in the electronic device 6. For example, the computer program 62 may be divided into modules 510 to 540 as shown in FIG. 5.

[0134] The electronic device 6 may include, but is not limited to, a processor 60 and a memory 61. Those skilled in the art will understand that FIG6 is merely an example of the electronic device 6 and does not constitute a limitation on the electronic device 6. It may include more or fewer components than illustrated, or combine certain components, or different components. For example, the electronic device may also include input / output devices, network access devices, buses, etc.

[0135] The processor 60 may be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor may be a microprocessor or any conventional processor.

[0136] The memory 61 can be an internal storage unit of the electronic device 6, such as a hard disk or memory. The memory 61 can also be an external storage device of the electronic device 6, such as a plug-in hard disk, smart media card (SMC), secure digital (SD) card, flash card, etc., equipped on the electronic device 6. Furthermore, the memory 61 can include both internal and external storage units of the electronic device 6. The memory 61 is used to store the computer program and other programs and data required by the electronic device. The memory 61 can also be used to temporarily store data that has been output or will be output.

[0137] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the above-described division of functional units and modules is merely an example. In practical applications, the above functions can be assigned to different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiments can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit. Furthermore, the specific names of the functional units and modules are only for easy differentiation and are not intended to limit the scope of protection of this application. The specific working process of the units and modules in the above system can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0138] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail or recorded in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0139] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0140] In the embodiments provided in this application, it should be understood that the disclosed devices / electronic devices and methods can be implemented in other ways. For example, the device / electronic device embodiments described above are merely illustrative. For instance, the division of modules or units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the displayed or discussed mutual couplings or direct couplings or communication connections may be through some interfaces; indirect couplings or communication connections between devices or units may be electrical, mechanical, or other forms.

[0141] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0142] Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0143] If the integrated module / unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, all or part of the processes in the above-described embodiments can also be implemented by a computer program instructing related hardware. The computer program can be stored in a computer-readable storage medium. When executed by a processor, the computer program can implement the steps of the above-described embodiments of the evaluation method for the dynamic diffusion of natural hydrogen in rock pores. The computer program includes computer program code, which can be in the form of source code, object code, executable files, or certain intermediate forms. The computer-readable storage medium can include: any entity or device capable of carrying the computer program code, a recording medium, a USB flash drive, a portable hard drive, a magnetic disk, an optical disk, a computer memory, a read-only memory (ROM), a random access memory (RAM), an electrical carrier signal, a telecommunication signal, and a software distribution medium, etc.

[0144] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A method for evaluating the dynamic diffusion of natural hydrogen in rock pores, characterized in that, include: Hydrogen adsorption simulation calculations were performed based on a pre-built pore model of the rock to be evaluated under target pressure and target temperature to determine the average number of hydrogen molecules adsorbed in the pores when hydrogen is saturated under the target temperature and pressure. Based on the lithological parameters of the rock to be evaluated, the average number of hydrogen molecules adsorbed in the pores under the target temperature and pressure, the target pressure, and the target temperature, the content of natural hydrogen in the rock pores is determined; the lithological parameters include the pore diameter, pore type influence coefficient, and pore specific surface area of ​​the rock to be evaluated. A preset gas is added to the pore model, and when the pore model is saturated at the target pressure and target temperature, the loss content of natural hydrogen is determined, and the diffusion coefficient of natural hydrogen is determined; wherein the preset gas is one or more gases other than hydrogen; and Based on the content of natural hydrogen in the rock pores, the loss of natural hydrogen, and the diffusion coefficient of natural hydrogen, diffusion evaluation parameters are determined.

2. The evaluation method as described in claim 1, characterized in that, The process of constructing the pore model is as follows: Based on the target test data of the rock to be evaluated, the full pore size distribution and pore throat diameter distribution of the rock to be evaluated are determined; wherein, the target test data includes scanning electron microscopy, high-pressure pump, and carbon dioxide / nitrogen adsorption test data; and Based on the full pore size distribution, the pore throat diameter distribution, and the mineral composition of the rock to be evaluated, a pore model of the rock to be evaluated is constructed.

3. The evaluation method as described in claim 1, characterized in that, The determination of the natural hydrogen content in the rock pores based on the lithological parameters of the rock to be evaluated, the average number of hydrogen molecules adsorbed in the pores under the target temperature and pressure, the target pressure, and the target temperature includes: The lithological parameters, the average number of hydrogen molecules adsorbed in the pores under the target temperature and pressure, the target pressure, and the target temperature are input into a pre-constructed ideal model for predicting the natural hydrogen content to obtain the content of natural hydrogen in the rock pores. Among them, the ideal model for predicting natural hydrogen content V 1H2 for: ； Among them, K i Let be the influence coefficient of the i-th rock pore type, n be the total number of rock pore type influence coefficients, T be the formation temperature, P be the formation pressure, D be the pore diameter, S be the pore specific surface area, and V be the pore diameter. m N is the gas volume under standard conditions, and N is the number of hydrogen molecules. A Let be Avogadro's constant, and a, b, c, and d be the fitting constants obtained based on the training samples.

4. The evaluation method as described in claim 1, characterized in that, The step of adding a preset gas to the pore model and determining the loss content of natural hydrogen when the pore model is saturated at the target pressure and target temperature includes: A preset gas is added to the pore model, and when the pore model is saturated at the target pressure and target temperature, the number of hydrogen molecules diffusing out of the pores is determined; and The loss content of natural hydrogen is determined based on the number of hydrogen molecules diffusing out of the pores and a preset hydrogen loss model; wherein the preset hydrogen loss model is determined based on the number of hydrogen molecules diffusing out of the pores and the gas volume under standard conditions.

5. The evaluation method as described in claim 4, characterized in that, The preset hydrogen loss model for: ； Among them, V m N is the gas volume under standard conditions, and N is the number of hydrogen molecules diffusing out of the pores. A is Avogadro's constant.

6. The evaluation method according to any one of claims 1-5, characterized in that, Determining the diffusion coefficient of natural hydrogen includes: The diffusion coefficient of the natural hydrogen is determined based on a preset diffusion coefficient correction model. The diffusion coefficient correction model DT H2 for: ； Among them, K i Let denoted as the influence coefficient of the i-th rock pore type, n be the total number of rock pore type influence coefficients, T be the formation temperature, P be the formation pressure, D be the pore diameter, and R be the pore throat diameter of the rock to be evaluated. DT j Let be the diffusion coefficient of any preset gas in the pore, m be the number of preset gas types, and h, r, k, e, and x be fitting constants obtained based on training samples.

7. The evaluation method according to any one of claims 1-5, characterized in that, The diffusion evaluation parameters are determined based on the content of natural hydrogen in the rock pores, the loss of natural hydrogen, and the diffusion coefficient of natural hydrogen, including: The content of natural hydrogen in the rock pores, the loss of natural hydrogen, and the diffusion coefficient of natural hydrogen are input into a pre-constructed diffusion evaluation model to obtain the diffusion coefficient of natural hydrogen in the rock pores to be evaluated. The diffusion evaluation model TC is as follows: ； The diffusion coefficient of the natural hydrogen gas is given. The loss content of the natural hydrogen gas. The content of natural hydrogen gas in the pores of the rock.

8. An evaluation device for the dynamic diffusion of natural hydrogen in rock pores, characterized in that, include: The first determination module is used to perform hydrogen adsorption simulation calculations based on a pre-built pore model of the rock to be evaluated under target pressure and target temperature, and to determine the average number of hydrogen molecules adsorbed in the pores when hydrogen is saturated under the target temperature and pressure. The second determining module is used to determine the content of natural hydrogen in the pores of the rock based on the lithological parameters of the rock to be evaluated, the average number of hydrogen molecules adsorbed in the pores under the target temperature and pressure, the target pressure, and the target temperature; the lithological parameters include the pore diameter, pore type influence coefficient, and pore specific surface area of ​​the rock to be evaluated. The third determining module is used to determine the loss content of natural hydrogen and the diffusion coefficient of natural hydrogen when the pore model is saturated at the target pressure and target temperature and a preset gas is added to the pore model; wherein the preset gas is one or more gases other than hydrogen; and The fourth determining module is used to determine diffusion evaluation parameters based on the content of natural hydrogen in the rock pores, the loss of natural hydrogen, and the diffusion coefficient of natural hydrogen.

9. An electronic device, characterized in that, The method includes a memory and a processor, the memory being used to store a computer program, and the processor being used to call and run the computer program stored in the memory to perform the method as described in any one of claims 1 to 7.

10. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by a processor, it implements the steps of the method as described in any one of claims 1 to 7.

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