Coal seam pore water occurrence form analysis method, device and equipment and storage medium

Abstract

The application provides a coal seam pore water occurrence form analysis method and device, equipment and a storage medium, and belongs to the technical field of pore water form analysis. The method comprises the following steps: obtaining each mineral component in a target coal sample and the pore size distribution of each mineral component, and obtaining a target mineral coupling model corresponding to the target coal sample; for each mineral component, determining the interfacial wettability weight coefficient of the mineral component, and determining the pore equivalent pore diameter of the mineral component; putting methane molecules and water molecules into the target mineral coupling model, and obtaining the position of the water molecules at each moment and the occupancy rate of the adsorption sites of the methane molecules on the surface of each mineral component at each moment in the evolution process; for each water molecule, determining the single water molecule dynamic binding strength index corresponding to the water molecule; and determining the occurrence form of the water molecule based on the single water molecule dynamic binding strength index and each mineral component. The application can determine the occurrence form of the coal seam pore water.

Description

Technical Field

[0001] This application belongs to the field of pore water morphology analysis technology, and more specifically, relates to a method, apparatus, equipment, and storage medium for analyzing the occurrence morphology of pore water in coal seams. Background Technology

[0002] The occurrence, distribution, and dynamic migration characteristics of pore water in coal seams are core factors influencing the adsorption, desorption, diffusion, and seepage processes of coalbed methane (CBM), directly determining the evaluation of CBM reservoir productivity, efficient development, and reservoir protection effectiveness. CBM reservoirs are typical multi-mineral composite porous media, containing various mineral components such as clay minerals, quartz, feldspar, and carbonates. The microscopic pore structure and surface physicochemical properties of different minerals vary significantly, resulting in drastically different adsorption, binding, and conduction effects on pore water. Multi-mineral coupling is the core mechanism regulating the occurrence and evolution of pore water in coal seams.

[0003] Existing studies on the spatial distribution and occurrence of pore water in coal seams are mostly limited to visual qualitative descriptions. They can only visually distinguish between areas of water accumulation and dispersion by relying on density cloud maps and molecular arrangement snapshots output by molecular simulations. At the same time, methane, as the main fluid component of coalbed methane, will continuously compete with water molecules for adsorption on the surface of mineral pores, making it difficult to determine the occurrence of pore water in coal seams. Summary of the Invention

[0004] The purpose of this application is to provide a method, apparatus, equipment, and storage medium for analyzing the occurrence morphology of pore water in coal seams, so as to determine the occurrence morphology of pore water in coal seams.

[0005] A first aspect of this application provides a method for analyzing the occurrence morphology of pore water in coal seams, including: The experiment obtains the mineral components and pore size distribution of each mineral component in the target coal sample after the experiment, and obtains the target mineral coupling model corresponding to the target coal sample; the target mineral coupling model is constructed by a horizontal single mineral layer stacking method; For each mineral component, the interfacial wettability weighting coefficient of that mineral component is determined, and the equivalent pore size of that mineral component is determined based on its pore size distribution; the interfacial wettability weighting coefficient is used to characterize the inherent water adsorption capacity of the mineral lattice surface of the corresponding mineral component. Methane and water molecules are introduced into the target mineral coupling model to enable the target mineral coupling model to perform molecular dynamics simulation evolution, and to obtain the position of water molecules at each time point during the evolution process and the occupancy rate of methane molecules on the adsorption sites of each mineral component at each time point. For each water molecule that is released, the dynamic binding strength index of a single water molecule is determined based on the interfacial wettability weighting coefficient of each mineral component, the equivalent pore size of each mineral component, the position of the water molecule at each time, and the occupancy rate of the adsorption sites of methane molecules on the surface of each mineral component at each time. The occurrence mode of the water molecule is determined based on the dynamic binding strength index of the single water molecule and each mineral component. The dynamic binding strength index of the single water molecule is used to characterize the degree to which the corresponding water molecule is bound by each mineral component at each time.

[0006] A second aspect of this application provides a device for analyzing the occurrence morphology of pore water in coal seams, comprising: The data acquisition module is used to acquire the mineral components and pore size distribution of each mineral component in the target coal sample after the experiment, and to acquire the target mineral coupling model corresponding to the target coal sample; the target mineral coupling model is constructed using a horizontal single mineral layer stacking method; The mineral component characteristic determination module is used to determine the interfacial wettability weight coefficient of each mineral component, and to determine the equivalent pore size of the mineral component based on its pore size distribution; the interfacial wettability weight coefficient is used to characterize the inherent water adsorption capacity of the mineral lattice surface of the corresponding mineral component. The simulation evolution module is used to introduce methane and water molecules into the target mineral coupling model so that the target mineral coupling model can perform molecular dynamics simulation evolution and obtain the position of water molecules at each time point during the evolution process and the occupancy rate of methane molecules on the adsorption sites of each mineral component at each time point. The morphology determination module is used to determine the dynamic binding strength index of a single water molecule for each water molecule that is introduced, based on the interfacial wettability weight coefficient of each mineral component, the equivalent pore size of each mineral component, the position of the water molecule at each time, and the occupancy rate of the adsorption sites of methane molecules on the surface of each mineral component at each time. Based on the dynamic binding strength index of the single water molecule and each mineral component, the morphology of the water molecule is determined. The dynamic binding strength index of the single water molecule is used to characterize the degree to which the corresponding water molecule is bound by each mineral component at each time.

[0007] A third aspect of this application provides an electronic device, including a memory, a processor, and a computer program stored in the memory and running on the processor, wherein the processor executes the computer program to implement the steps of the above-described method for analyzing the occurrence morphology of pore water in coal seams.

[0008] In a fourth aspect of this application, a computer-readable storage medium is provided, which stores a computer program that, when executed by a processor, implements the steps of the above-described method for analyzing the occurrence morphology of pore water in coal seams.

[0009] The beneficial effects of the coal seam pore water occurrence morphology analysis method, apparatus, equipment, and storage medium provided in this application embodiment are as follows: This embodiment establishes a horizontal single-mineral layered stacking coupling model based on the measured mineral composition and pore size distribution of coal samples to solve the simulation distortion problem caused by the differences in pore structure and surface physicochemical properties of different minerals. Secondly, this embodiment introduces an interface wettability weighting coefficient and equivalent pore size to quantify the inherent water absorption capacity and pore confinement effect of different minerals. It simultaneously collects the temporal sequence of water molecule positions and methane adsorption site occupancy rates based on molecular dynamics. The analysis considers the intrinsic properties of multiple minerals, pore space effects, and microscopic effects such as methane competitive adsorption. Through the dynamic binding strength index of a single water molecule, it achieves single-molecule, temporal quantitative quantification of the binding strength of minerals on water molecules, and can automatically determine the occurrence form of pore water. Attached Figure Description

[0010] 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.

[0011] Figure 1 A flowchart illustrating a method for analyzing the occurrence morphology of pore water in coal seams according to an embodiment of this application; Figure 2 This is a schematic diagram of the structure of a target mineral coupling model provided in an embodiment of this application; Figure 3 This is a schematic diagram illustrating the migration of water molecules after they are introduced into a target mineral coupling model, according to an embodiment of this application. Figure 4 A structural block diagram of a coal seam pore water occurrence morphology analysis device provided in an embodiment of this application; Figure 5 This is a schematic block diagram of an electronic device provided in an embodiment of this application. Detailed Implementation

[0012] 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.

[0013] 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.

[0014] Please refer to Figure 1 , Figure 1 This is a flowchart illustrating a method for analyzing the occurrence morphology of pore water in coal seams according to an embodiment of this application. This method can be executed by an electronic device and may include: S101: Obtain the mineral components and pore size distribution of each mineral component in the target coal sample after the experiment is conducted on the target coal sample, and obtain the target mineral coupling model corresponding to the target coal sample.

[0015] In this embodiment, the target coal sample refers to a representative rock sample collected from the coal seam to be studied. Mineral composition refers to the different types of minerals contained in the coal sample, such as quartz, montmorillonite, and illite; their types and contents can be determined by X-ray diffraction (XRD) experiments. Pore size distribution refers to the volume percentage of pores of different sizes in the coal sample, which can be obtained through solid-state carbon nuclear magnetic resonance (NMR) experiments.

[0016] In this embodiment, the target mineral coupling model is used to simulate the microstructure of multiple minerals coexisting in coal and rock. It is constructed by a horizontal single mineral layer stacking method, that is, different minerals are stacked in a certain direction in the form of independent thin layers without atomic mixing, so as to simulate the characteristics of mineral layer deposition in nature.

[0017] In one embodiment of this application, the process of constructing the target mineral coupling model includes: Obtain the composition and percentage of each mineral component in the target coal sample; For each mineral component, the thickness of the mineral layer corresponding to that mineral component is determined based on its proportion. Based on the thickness of the mineral layers corresponding to each mineral component, a target mineral coupling model is constructed by stacking the mineral layers in a horizontally single manner.

[0018] In this embodiment, reference Figure 2 , Figure 2The target mineral coupling model contains three mineral components, from left to right: montmorillonite, illite, and quartz. When constructing the mineral coupling model, the pore size distribution of each mineral component should also be considered to ensure the model closely reflects reality. The mineral components can be ordered according to their proportions, from highest to lowest. The thickness of each mineral layer is then determined, and the model is constructed from left to right using a single horizontal stacking method to obtain the final target mineral coupling model.

[0019] S102: For each mineral component, determine the interfacial wettability weighting coefficient of the mineral component, and determine the equivalent pore size of the mineral component based on the pore size distribution of the mineral component.

[0020] In this embodiment, the interface wettability weighting coefficient is used to characterize the inherent water adsorption capacity of the mineral lattice surface of the corresponding mineral component; the larger the value, the stronger the adsorption capacity of the mineral surface for water molecules. The equivalent pore size refers to a characteristic size parameter for the pore structure of a specific mineral layer in the model, used to characterize the narrowness of the pores.

[0021] In this embodiment, the strength of each mineral component's adsorption capacity for water molecules can be set. After determining the various mineral components of the target coal sample, the interfacial wettability weighting coefficient can be determined based on the strength of each mineral component's adsorption capacity for water molecules. - Quartz as the benchmark mineral ( The adsorption energy of a single molecule was calculated using density functional theory after the mineral composition was identified by X-ray diffraction (XRD) experiments.

[0022] In this embodiment, for each mineral component, the volume-weighted average of all pore diameters of that mineral component can be performed to obtain the equivalent pore diameter of that mineral component.

[0023] S103: Introduce methane and water molecules into the target mineral coupling model to enable the target mineral coupling model to perform molecular dynamics simulation evolution, and obtain the position of water molecules at each moment during the evolution process and the occupancy rate of methane molecules on the adsorption sites of each mineral component at each moment.

[0024] In this embodiment, a predetermined number of water molecules and methane molecules are randomly introduced into the constructed target mineral coupling model. Parameters for the molecular dynamics simulation, such as force field, temperature, and pressure, are set, and the simulation is run. During the evolution process, the coordinates of each water molecule and the occupancy rate of the adsorption sites of methane molecules on the surfaces of each mineral component are tracked and extracted in real time.

[0025] In this embodiment, reference Figure 3 , Figure 3 This is to obtain the morphology and migration of water molecules at a certain moment after water molecules are introduced into the coupled model of the target mineral and molecular dynamics simulation is performed.

[0026] S104: For each water molecule that is released, the dynamic binding strength index of a single water molecule is determined based on the interfacial wettability weight coefficient of each mineral component, the equivalent pore size of each mineral component, the position of the water molecule at each time, and the occupancy rate of the adsorption sites of methane molecules on the surface of each mineral component at each time; the occurrence form of the water molecule is determined based on the dynamic binding strength index of the single water molecule and each mineral component.

[0027] In this embodiment, the occurrence state of water molecules may include adsorbed state, thin film state or free state.

[0028] In this embodiment, for each water molecule in the simulation system, at each moment, the interfacial wettability weight coefficient of each mineral component, the equivalent pore size, and the real-time acquired position information of the water molecule and the methane adsorption site occupancy rate are called and substituted into the preset calculation formula to calculate the single water molecule dynamic binding strength index at that moment.

[0029] In this embodiment, the calculated dynamic binding strength index of a single water molecule can be compared with the water molecule occurrence morphology classification threshold to determine whether the water molecule is currently in an adsorbed state, a thin film state, or a free state. Different mineral components can correspond to different water molecule occurrence morphology classification thresholds.

[0030] As can be seen from the above, this embodiment establishes a horizontal single-mineral layered stacking coupling model based on the measured mineral composition and pore size distribution of coal samples, solving the simulation distortion problem caused by the differences in pore structure and surface physicochemical properties of different minerals. Secondly, this embodiment introduces an interface wettability weighting coefficient and pore equivalent pore size to quantify the inherent water absorption capacity and pore confinement effect of different minerals. It simultaneously collects the molecular dynamics time-series water molecule positions and methane adsorption site occupancy rates, and considers the intrinsic properties of multiple minerals, pore space effects, methane competitive adsorption, and other microscopic effects in the analysis. Through the single-water molecule dynamic binding strength index, it realizes the single-molecule, time-series quantitative quantification of the binding strength of minerals on water molecules, and can automatically determine the occurrence form of pore water.

[0031] In one embodiment of this application, the dynamic binding strength index of a single water molecule is used to characterize the degree to which the corresponding water molecule is bound by each mineral component at each time.

[0032] In this embodiment, for each moment in the evolution process, based on the interfacial wettability weighting coefficient of each mineral component, the equivalent pore size of each mineral component, the position of the water molecule at that moment, and the occupancy rate of the adsorption sites of the methane molecule on the surface of each mineral component at that moment, the dynamic binding strength index of the single water molecule at that moment is determined, including: Based on the position of the water molecule at that moment, determine the normal distance between the water molecule and each mineral layer in the target mineral coupling model at that moment, and the occupancy rate of the methane molecule adsorption sites within the preset radius range at that moment. Based on the normal distance, the distance attenuation factor of each mineral layer corresponding to the water molecule at that moment is determined; the distance attenuation factor is used to characterize the degree of attenuation of the binding force caused by the change in the interface distance between the water molecule and the corresponding mineral layer. Based on the equivalent pore size of the mineral components corresponding to each mineral layer, the superposition factor of the confined force field for each mineral layer corresponding to the water molecule is determined; the superposition factor of the confined force field is used to characterize the superposition enhancement effect of the molecular force field on both sides of the mineral layer within the slit pore. The competitive perturbation factor corresponding to the water molecule at that moment is determined based on the occupancy rate of the adsorption site; the competitive perturbation factor is used to characterize the extent to which the methane molecule weakens the inherent water binding ability of the mineral after occupying the adsorption site on the mineral surface. The dynamic binding strength index of a single water molecule at a given moment is determined based on the interfacial wettability weighting coefficient, distance attenuation factor, superposition factor of confined force field, and competing disturbance factor of each mineral component.

[0033] In one embodiment, the process of determining the dynamic binding strength index of a single water molecule at a given moment based on the interfacial wettability weighting coefficient, distance attenuation factor, confined force field superposition factor, and competing disturbance factor of each mineral component is implemented based on the following formula: ; in, Let be the distance attenuation factor of the mineral layer corresponding to the j-th mineral component at time t for the i-th water molecule; The superposition factor of the confined force field of the mineral layer corresponding to the j-th mineral component of the i-th water molecule; This represents the competitive perturbation factor corresponding to the i-th water molecule at time t; in, Let be the dynamic binding strength index of the i-th water molecule relative to the j-th mineral component at time t, used to characterize the degree to which the i-th water molecule is bound by the j-th mineral component at time t. This represents the interfacial wettability weighting coefficient of the j-th mineral component; This represents the normal distance between the i-th water molecule and the mineral layer of the j-th mineral component at time t; The characteristic decay length of interfacial molecular forces is used to characterize the exponential decay of intermolecular forces on the mineral surface with respect to normal distance. This represents the equivalent pore size of the j-th mineral component; The methane competitive adsorption shielding coefficient is used to characterize the efficiency of methane molecules occupying adsorption sites on the mineral surface in weakening the binding strength of water molecules. This represents the occupancy rate of the adsorption sites of methane molecules within a preset radius range for the i-th water molecule at time t.

[0034] In practical implementation, for a specific time t in the molecular dynamics simulation trajectory and a specific water molecule i to be analyzed, firstly, all mineral layers in the model are traversed, and the normal distance from the water molecule i to the surface of each mineral layer j is calculated. The unit is Å. This can be achieved by calculating the difference between the coordinates of a water molecule and the atomic coordinates of the mineral layer surface in the direction perpendicular to the layer. Simultaneously, a spherical search range with a preset radius (e.g., 5 Å) is set around this water molecule, and the number of methane molecules located on the mineral surface within this range is counted, and their occupancy rate is calculated. .

[0035] Next, based on the calculated normal distance The distance attenuation factor is determined. This embodiment uses an exponential attenuation function. To characterize, among which The characteristic decay length of interfacial molecular forces is an empirical constant that can be set to 10 Å, representing the effective range of hydrogen bonds and van der Waals forces.

[0036] Then, the equivalent pore size of the mineral layer j based on the location of the water molecule. (Unit: Å), determine the superposition factor of the confined force field. This embodiment uses... It is characterized in the form of pore equivalent pore size. When the value is small, the factor value is large, indicating that the superposition effect of the force fields on both sides of the pore wall is significant, which enhances the binding of water molecules.

[0037] Subsequently, based on the methane adsorption site occupancy rate at that moment... The competition disturbance factor is determined. This embodiment uses... It is represented in the form of, where The methane competitive adsorption shielding coefficient is an empirical parameter between 0 and 1, which can be obtained through simulation calibration, for example, set to 0.8. This factor indicates that as the methane occupancy rate increases... As the concentration of water increases, the binding force on water molecules will weaken accordingly.

[0038] Finally, the interfacial wettability weighting coefficient of this mineral component is determined. Multiplying the (dimensionless) calculated distance attenuation factor, confined force field superposition factor, and competing disturbance factor, we can obtain the dynamic binding strength index of a single water molecule i relative to the mineral layer j at time t. .

[0039] In one embodiment of this application, the occurrence mode of the water molecule is determined based on the dynamic binding strength index of the corresponding single water molecule and the various mineral components, including: Determine the threshold for the water molecule occurrence morphology classification corresponding to each mineral component. For each moment in the evolution process, the occurrence form of the water molecule relative to each mineral component at that moment is determined based on the dynamic binding strength index of the single water molecule at that moment and the threshold for the occurrence form of water molecules corresponding to each mineral component; the occurrence form of the water molecule at that moment is determined based on the occurrence form of the water molecule relative to each mineral component at that moment and the priority order of the occurrence forms.

[0040] In this embodiment, the priority order of occurrence states refers to the rules used to ultimately determine the unique state of a water molecule when it is simultaneously affected by multiple mineral layers and may be classified into multiple occurrence states. Generally, the state with the strongest binding force has the highest priority, i.e., the priority order is: adsorbed water > thin film water > free water.

[0041] In this embodiment, the water molecule occurrence morphology classification threshold includes: a first classification threshold and a second classification threshold for each mineral component. The first classification threshold is used to classify adsorbed water and thin film water; the second classification threshold is used to classify thin film water and free water. Determine the threshold for the water molecule occurrence format classification corresponding to each mineral component, including: Obtain a first dividing criterion and a second dividing criterion; the first dividing criterion is the dynamic binding strength index of a single water molecule when adsorbed water undergoes a morphological transformation to thin film water under a preset benchmark mineral; the second dividing criterion is the dynamic binding strength index of a single water molecule when thin film water undergoes a morphological transformation to free water under a preset benchmark mineral. For each mineral component, a first classification threshold is determined based on the interfacial wettability weighting coefficient of the mineral component and a first classification criterion; a second classification threshold is determined based on the interfacial wettability weighting coefficient of the mineral component and a second classification criterion.

[0042] In this embodiment, the product of the interfacial wettability weight coefficient of the mineral component and the first dividing criterion can be determined as the first dividing threshold of the mineral component, and the product of the interfacial wettability weight coefficient of the mineral component and the second dividing criterion can be determined as the second dividing threshold of the mineral component.

[0043] In this embodiment, the process of determining the first dividing datum and the second dividing datum includes: A baseline pore model composed of pre-defined reference minerals is constructed, water molecules are introduced into the baseline pore model, and molecular dynamics simulations are performed until the system reaches statistical steady state. The dynamic binding strength index of a single water molecule at different positions during the steady-state simulation phase was collected to obtain the continuous decay distribution curve of the binding strength. Based on the distribution inflection point characteristics of the continuous decay distribution curve of the binding strength, the dynamic binding strength index of a single water molecule corresponding to the boundary position between adsorbed water and thin film water is extracted as the first dividing criterion. Based on another distribution inflection point feature of the continuous decay distribution curve of the binding strength, the dynamic binding strength index of a single water molecule corresponding to the boundary position between the thin film water and free water is extracted as the second dividing criterion.

[0044] In this embodiment, firstly, in an ideal reference system without interference, the physical anchor point of the occurrence form boundary is determined based on the microscopic physical state of water molecules (density distribution, adsorption energy level, migration ability), and then mapped to the numerical threshold of the binding strength index. Finally, it can be extended to adapt to all scenarios of multi-mineral, multi-scale pores, and methane displacement, ensuring the physical nature of the discrimination standard is consistent.

[0045] Specifically, using an infinitely large smooth cleavage plane of α-quartz and a pure water equilibrium system as the calibration benchmark, under these conditions, the intrinsic properties of the minerals... ; =1; Competition Disturbance Factor =1. At this point, the dynamic binding strength exponent of a single water molecule degenerates into a univariate function that depends only on the normal distance:

[0046] In the formula This represents the dynamic binding strength index of a single water molecule under the calibration benchmark. This application establishes two energy boundary standards: the lower limit energy of adsorbed water, E1, is 15 kcal / mol, corresponding to the lower limit of strong hydrogen bonding on the mineral surface; the upper limit energy of free water, E2, is 5 kcal / mol, corresponding to the lower limit of weak van der Waals interactions; the area between these two is a transitional thin-film water bound by secondary intermolecular forces. This division matches the range of hydroxyl interaction strength in coal seam minerals. During the calculation, a quartz periodic plate model is constructed, and GGA-PBE functional theory combined with DFT-D3 dispersion correction is used. The single-molecule adsorption energy is calculated by scanning along the normal 0~20 Å interval with a step size of 0.5 Å, obtaining a continuous decay distribution curve of adsorption strength with normal distance. In this embodiment, the distribution inflection point characteristic refers to the characteristic distances h1 and h2 corresponding to E1 and E2. Substituting h1 and h2 into the above formula yields the first dividing benchmark. Second dividing benchmark , that is , In this embodiment, the inflection point refers to the lower limit energy of adsorbed water E1 and the upper limit energy of free water E2.

[0047] As can be seen from the above, this embodiment decomposes the microscopic effect of water molecules being bound by minerals into four independent physical factors. A standardized formula for calculating the binding strength is constructed by coupling the inherent wettability of minerals with the distance attenuation factor, the confined force field superposition factor, and the competitive perturbation factor. This covers four influencing mechanisms: intrinsic mineral adsorption properties, pore size effect, intermolecular distance attenuation, and methane competitive adsorption. Compared to existing methods that rely solely on visual cloud maps for qualitative interpretation, this achieves quantitative characterization of single molecules across the entire time series, eliminating subjective errors caused by manual image interpretation. Furthermore, this embodiment establishes a unified and adaptable morphology discrimination scale for multi-mineral systems, solving the problem of inaccurate classification at differential mineral interfaces using a single fixed threshold.

[0048] In one embodiment of this application, the transport patterns of water molecules can also be analyzed based on parameters during the evolution process. For example, if the total number of water molecules in the system is set to N, the macroscopic transport capability of porous water molecules can be quantitatively characterized using the mean square displacement formula of water molecules and the self-diffusion coefficient. This is verified by the microscopic effect-macroscopic characteristic correspondence with the single-molecule binding strength index. At the same time, the mean square displacement can reflect the spatial migration amplitude of water molecules over time. The calculation formula is as follows:

[0049] In the formula, MSD(t) is the mean square displacement of water molecules at time t (Ų), N is the total number of water molecules in the system, and ri(t) and ri(0) are the spatial coordinates (Å) of the i-th water molecule at time t and the initial time, respectively. Based on the mean square displacement calculation results, the overall diffusion and transport capacity of the water phase in a methane-filled environment is quantitatively evaluated using the water molecule diffusion coefficient calculation formula. The diffusion coefficient and the dynamic binding strength index of a single water molecule show a negative correlation, which can verify the intrinsic relationship between the water phase occurrence form and transport capacity at the system level. The calculation formula is as follows:

[0050] In the formula, D is the water molecule diffusion coefficient (Ų / ps). denoted as the rate of change of the mean square displacement over time.

[0051] CV is defined as the coefficient of variation of aqueous phase density. The formula for calculating the coefficient of variation of aqueous phase density is used to evaluate the non-uniformity of the spatial distribution of water molecules within the stratified pores of multiple minerals after methane intrusion. This accurately reflects the regulatory effect of methane on the aggregation and dispersion of the aqueous phase. A larger CV value indicates stronger heterogeneity in the spatial distribution of the aqueous phase under the influence of methane, and more significant differences in the occurrence of multiple minerals. The calculation formula is as follows:

[0052] In the formula, CV is the coefficient of variation of the water phase density. The standard deviation of water phase density (g / cm³) in the pores of different mineral layers. The average density of the water phase within the pores of the entire model is given in g / cm³.

[0053] Corresponding to the coal seam pore water occurrence morphology analysis method in the above embodiment, Figure 4 This is a structural block diagram of a coal seam pore water occurrence morphology analysis device provided in one embodiment of this application. For ease of explanation, only the parts relevant to the embodiment of this application are shown. References Figure 4 The coal seam pore water occurrence morphology analysis device 40 includes: a data acquisition module 41, a mineral component characteristic determination module 42, a simulation evolution module 43, and an occurrence morphology determination module 44.

[0054] The data acquisition module 41 is used to acquire the mineral components and pore size distribution of each mineral component in the target coal sample after the experiment is conducted on the target coal sample, and to acquire the target mineral coupling model corresponding to the target coal sample; the target mineral coupling model is constructed by a horizontal single mineral layer stacking method. The mineral component characteristic determination module 42 is used to determine the interfacial wettability weight coefficient of each mineral component, and to determine the equivalent pore size of the mineral component based on the pore size distribution of the mineral component; the interfacial wettability weight coefficient is used to characterize the inherent water adsorption capacity of the mineral lattice surface of the corresponding mineral component. The simulation evolution module 43 is used to introduce methane molecules and water molecules into the target mineral coupling model so that the target mineral coupling model can perform molecular dynamics simulation evolution and obtain the position of water molecules at each time point during the evolution process and the occupancy rate of methane molecules on the adsorption sites of each mineral component at each time point. The morphology determination module 44 is used to determine the dynamic binding strength index of a single water molecule for each water molecule that is released, based on the interfacial wettability weight coefficient of each mineral component, the equivalent pore size of each mineral component, the position of the water molecule at each time, and the occupancy rate of the adsorption sites of methane molecules on the surface of each mineral component at each time. Based on the dynamic binding strength index of the single water molecule and each mineral component, the morphology of the water molecule is determined. The dynamic binding strength index of the single water molecule is used to characterize the degree to which the corresponding water molecule is bound by each mineral component at each time.

[0055] In one embodiment of this application, for each moment in the evolution process, the morphology determination module 44 is specifically used to determine the normal distance between the water molecule and each mineral layer in the target mineral coupling model at that moment, and the occupancy rate of the adsorption sites of methane molecules within a preset radius range of the water molecule at that moment, based on the position of the water molecule at that moment. Based on the normal distance, the distance attenuation factor of each mineral layer corresponding to the water molecule at that moment is determined; the distance attenuation factor is used to characterize the degree of attenuation of the binding force caused by the change in the interface distance between the water molecule and the corresponding mineral layer. Based on the equivalent pore size of the mineral components corresponding to each mineral layer, the superposition factor of the confined force field for each mineral layer corresponding to the water molecule is determined; the superposition factor of the confined force field is used to characterize the superposition enhancement effect of the molecular force field on both sides of the mineral layer within the slit pore. The competitive perturbation factor corresponding to the water molecule at that moment is determined based on the occupancy rate of the adsorption site; the competitive perturbation factor is used to characterize the extent to which the methane molecule weakens the inherent water binding ability of the mineral after occupying the adsorption site on the mineral surface. The dynamic binding strength index of a single water molecule at a given moment is determined based on the interfacial wettability weighting coefficient, distance attenuation factor, superposition factor of confined force field, and competing disturbance factor of each mineral component.

[0056] In one embodiment of this application, the morphology determination module 44 is specifically used to determine the dynamic binding strength index of a single water molecule at a given moment based on the following formula: ; in, Let be the distance attenuation factor of the mineral layer corresponding to the j-th mineral component at time t for the i-th water molecule; The superposition factor of the confined force field of the mineral layer corresponding to the j-th mineral component of the i-th water molecule; This represents the competitive perturbation factor corresponding to the i-th water molecule at time t; in, Let be the dynamic binding strength index of the i-th water molecule relative to the j-th mineral component at time t, used to characterize the degree to which the i-th water molecule is bound by the j-th mineral component at time t. This represents the interfacial wettability weighting coefficient of the j-th mineral component; This represents the normal distance between the i-th water molecule and the mineral layer of the j-th mineral component at time t; The characteristic decay length of interfacial molecular forces is used to characterize the exponential decay of intermolecular forces on the mineral surface with respect to normal distance. This represents the equivalent pore size of the j-th mineral component; The methane competitive adsorption shielding coefficient is used to characterize the efficiency of methane molecules occupying adsorption sites on the mineral surface in weakening the binding strength of water molecules. This represents the occupancy rate of the adsorption sites of methane molecules within a preset radius range for the i-th water molecule at time t.

[0057] In one embodiment of this application, the morphology determination module 44 is specifically used to determine the water molecule morphology division threshold corresponding to each mineral component. For each moment in the evolution process, the occurrence form of the water molecule relative to each mineral component at that moment is determined based on the dynamic binding strength index of the single water molecule at that moment and the threshold for the occurrence form of water molecules corresponding to each mineral component; the occurrence form of the water molecule at that moment is determined based on the occurrence form of the water molecule relative to each mineral component at that moment and the priority order of the occurrence forms.

[0058] In one embodiment of this application, the water molecule occurrence morphology classification threshold includes: a first classification threshold and a second classification threshold for each mineral component, wherein the first classification threshold is used to classify adsorbed water and thin film water; and the second classification threshold is used to classify thin film water and free water. The morphology determination module 44 is specifically used to obtain the first division criterion and the second division criterion; the first division criterion is the dynamic binding strength index of a single water molecule when the adsorbed water undergoes a morphological transformation to thin film water under a preset reference mineral; the second division criterion is the dynamic binding strength index of a single water molecule when the thin film water undergoes a morphological transformation to free water under a preset reference mineral. For each mineral component, a first classification threshold is determined based on the interfacial wettability weighting coefficient of the mineral component and a first classification criterion; a second classification threshold is determined based on the interfacial wettability weighting coefficient of the mineral component and a second classification criterion.

[0059] In one embodiment of this application, the coal seam pore water occurrence morphology analysis device 40 further includes: a benchmark determination module, used to construct a benchmark pore model composed of preset benchmark minerals, add water molecules into the benchmark pore model, and perform molecular dynamics simulation until the system reaches statistical steady state; The dynamic binding strength index of a single water molecule at different positions during the steady-state simulation phase was collected to obtain the continuous decay distribution curve of the binding strength. Based on the distribution inflection point characteristics of the continuous decay distribution curve of the binding strength, the dynamic binding strength index of a single water molecule corresponding to the boundary position between adsorbed water and thin film water is extracted as the first dividing criterion. Based on another distribution inflection point feature of the continuous decay distribution curve of the binding strength, the dynamic binding strength index of a single water molecule corresponding to the boundary position between the thin film water and free water is extracted as the second dividing criterion.

[0060] In one embodiment of this application, the coal seam pore water occurrence morphology analysis device 40 further includes: a target mineral coupling model determination module, used to obtain the various mineral components and the proportion of each mineral component in the target coal sample; For each mineral component, the thickness of the mineral layer corresponding to that mineral component is determined based on its proportion. Based on the thickness of the mineral layers corresponding to each mineral component, a target mineral coupling model is constructed by stacking the mineral layers in a horizontally single manner.

[0061] See Figure 5 , Figure 5 This is a schematic block diagram of an electronic device provided according to an embodiment of this application. Figure 5 The electronic device 300 in this embodiment may include one or more processors 301, one or more input devices 302, one or more output devices 303, and one or more memories 304. The processors 301, input devices 302, output devices 303, and memories 304 communicate with each other via a communication bus 305. The memories 304 store computer programs, including program instructions. The processors 301 execute the program instructions stored in the memories 304. Specifically, the processors 301 are configured to invoke the program instructions to perform the functions of each module / unit in the above-described device embodiments, for example... Figure 4 The functions of the data acquisition module 41, the mineral component characteristic determination module 42, the simulation evolution module 43, and the occurrence morphology determination module 44 are described.

[0062] It should be understood that, in the embodiments of this application, the processor 301 may be a central processing unit (CPU), but it may also be 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. The general-purpose processor may be a microprocessor or any conventional processor.

[0063] Input device 302 may include a touchpad, a fingerprint sensor (for collecting the user's fingerprint information and fingerprint orientation information), a microphone, etc., and output device 303 may include a display (LCD, etc.), a speaker, etc.

[0064] The memory 304 may include read-only memory and random access memory, and provides instructions and data to the processor 301. A portion of the memory 304 may also include non-volatile random access memory. For example, the memory 304 may also store device type information.

[0065] In specific implementations, the processor 301, input device 302, and output device 303 described in the embodiments of this application can execute the implementation method described in the coal seam pore water occurrence morphology analysis method provided in the embodiments of this application, or they can execute the implementation method of the electronic device described in the embodiments of this application, which will not be repeated here.

[0066] In another embodiment of this application, a computer-readable storage medium is provided. This computer-readable storage medium stores a computer program, which includes program instructions. When executed by a processor, the program instructions implement all or part of the processes in the methods described above. Alternatively, the computer program can instruct related hardware to complete the process. The computer program can be stored in a computer-readable storage medium, and when executed by a processor, it can implement the steps of the various method embodiments described above. 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 medium can include any entity or device capable of carrying 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.

[0067] The computer-readable storage medium can be an internal storage unit of the electronic device in any of the foregoing embodiments, such as a hard disk or memory of the electronic device. The computer-readable storage medium can also be an external storage device of the electronic device, such as a plug-in hard disk, smart media card (SMC), secure digital card (SD), flash card, etc., equipped on the electronic device. Furthermore, the computer-readable storage medium can include both internal and external storage units of the electronic device. The computer-readable storage medium is used to store computer programs and other programs and data required by the electronic device. The computer-readable storage medium can also be used to temporarily store data that has been output or will be output.

[0068] 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, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the components and steps of the various examples have been generally described in terms of functionality in the foregoing description. 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 implementations should not be considered beyond the scope of this application.

[0069] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working process of the electronic devices and units described above can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0070] In the several embodiments provided in this application, it should be understood that the disclosed electronic devices and methods can be implemented in other ways. For example, the device embodiments described above are merely illustrative; for instance, the division of 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. In addition, the mutual coupling or direct coupling or communication connection shown or discussed may be indirect coupling or communication connection through some interfaces or units, or it may be an electrical, mechanical, or other form of connection.

[0071] 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 the embodiments of this application, depending on actual needs.

[0072] 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.

[0073] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, data stored, data displayed, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties, and the collection, use and processing of related data must comply with the relevant laws, regulations and standards of the relevant countries and regions.

[0074] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in this application, and these modifications or substitutions should all be covered within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for analyzing the occurrence morphology of pore water in coal seams, characterized in that, include: The method obtains the mineral components and pore size distribution of each mineral component in the target coal sample after the experiment is conducted on the target coal sample, and obtains the target mineral coupling model corresponding to the target coal sample. The target mineral coupling model is constructed using a horizontally single mineral layer stacking method; For each mineral component, an interfacial wettability weighting coefficient is determined, and the equivalent pore size of the mineral component is determined based on its pore size distribution; the interfacial wettability weighting coefficient is used to characterize the inherent water adsorption capacity of the mineral lattice surface of the corresponding mineral component. Methane and water molecules are introduced into the target mineral coupling model to enable the target mineral coupling model to perform molecular dynamics simulation evolution, and to obtain the position of water molecules at each moment during the evolution process and the occupancy rate of methane molecules on the adsorption sites of each mineral component at each moment. For each water molecule that is released, the dynamic binding strength index of a single water molecule is determined based on the interfacial wettability weighting coefficient of each mineral component, the equivalent pore size of each mineral component, the position of the water molecule at each time point, and the occupancy rate of the adsorption sites of methane molecules on the surface of each mineral component at each time point. The occurrence mode of the water molecule is determined based on the dynamic binding strength index of the single water molecule and the mineral components. The dynamic binding strength index of the single water molecule is used to characterize the degree to which the corresponding water molecule is bound by each mineral component at each time point.

2. The method for analyzing the occurrence morphology of pore water in coal seams as described in claim 1, characterized in that, For each moment in the evolution process, based on the interfacial wettability weighting coefficient of each mineral component, the equivalent pore size of each mineral component, the position of the water molecule at that moment, and the occupancy rate of the adsorption sites of the methane molecule on the surface of each mineral component at that moment, the dynamic binding strength index of the single water molecule at that moment is determined, including: Based on the position of the water molecule at that moment, determine the normal distance between the water molecule and each mineral layer in the target mineral coupling model at that moment, and the occupancy rate of the methane molecule adsorption sites within the preset radius range at that moment. Based on the normal distance, the distance attenuation factor of each mineral layer corresponding to the water molecule at that moment is determined; the distance attenuation factor is used to characterize the degree of attenuation of the binding force caused by the change in the interface distance between the water molecule and the corresponding mineral layer. Based on the equivalent pore size of the mineral components corresponding to each mineral layer, the superposition factor of the confined force field for each mineral layer corresponding to the water molecule is determined; the superposition factor of the confined force field is used to characterize the superposition enhancement effect of the molecular force field on both sides of the mineral layer within the slit pore. The competitive perturbation factor corresponding to the water molecule at that moment is determined based on the occupancy rate of the adsorption sites; the competitive perturbation factor is used to characterize the extent to which the methane molecule weakens the inherent water binding ability of the mineral after occupying the adsorption sites on the mineral surface. The dynamic binding strength index of a single water molecule at a given moment is determined based on the interfacial wettability weighting coefficient of each mineral component, the distance attenuation factor, the superposition factor of the confined force field, and the competing disturbance factor.

3. The method for analyzing the occurrence morphology of pore water in coal seams as described in claim 2, characterized in that, The process of determining the dynamic binding strength index of a single water molecule at a given moment based on the interfacial wettability weighting coefficient of each mineral component, the distance attenuation factor, the confined force field superposition factor, and the competing disturbance factor is implemented based on the following formula: ； in, Let be the distance attenuation factor of the mineral layer corresponding to the j-th mineral component at time t for the i-th water molecule; The superposition factor of the confined force field of the mineral layer corresponding to the j-th mineral component of the i-th water molecule; This represents the competitive perturbation factor corresponding to the i-th water molecule at time t; in, Let be the dynamic binding strength index of the i-th water molecule relative to the j-th mineral component at time t, used to characterize the degree to which the i-th water molecule is bound by the j-th mineral component at time t. This represents the interfacial wettability weighting coefficient of the j-th mineral component; This represents the normal distance between the i-th water molecule and the mineral layer of the j-th mineral component at time t; The characteristic decay length of interfacial molecular forces is used to characterize the exponential decay of intermolecular forces on the mineral surface with respect to normal distance. This represents the equivalent pore size of the j-th mineral component; The methane competitive adsorption shielding coefficient is used to characterize the efficiency of methane molecules occupying adsorption sites on the mineral surface in weakening the binding strength of water molecules. This represents the occupancy rate of the adsorption sites of methane molecules within a preset radius range for the i-th water molecule at time t.

4. The method for analyzing the occurrence morphology of coal seam pore water as described in claim 1, characterized in that, The determination of the occurrence form of the water molecule based on the corresponding single water molecule dynamic binding strength index and the various mineral components includes: Determine the threshold for the water molecule occurrence morphology classification corresponding to each mineral component. For each moment in the evolution process, the occurrence form of the water molecule relative to each mineral component at that moment is determined based on the dynamic binding strength index of the single water molecule at that moment and the threshold for the occurrence form of water molecules corresponding to each mineral component; the occurrence form of the water molecule at that moment is determined based on the occurrence form of the water molecule relative to each mineral component at that moment and the priority order of the occurrence forms.

5. The method for analyzing the occurrence morphology of pore water in coal seams as described in claim 4, characterized in that, The water molecule occurrence morphology classification threshold includes: a first classification threshold and a second classification threshold for each mineral component, wherein the first classification threshold is used to classify adsorbed water and thin film water; and the second classification threshold is used to classify thin film water and free water. The determination of the threshold for the water molecule occurrence morphology classification corresponding to each mineral component includes: Obtain a first dividing criterion and a second dividing criterion; the first dividing criterion is the dynamic binding strength index of a single water molecule when adsorbed water undergoes a morphological transformation to thin film water under a preset benchmark mineral; the second dividing criterion is the dynamic binding strength index of a single water molecule when thin film water undergoes a morphological transformation to free water under a preset benchmark mineral. For each mineral component, a first classification threshold is determined based on the interfacial wettability weighting coefficient of the mineral component and the first classification criterion; a second classification threshold is determined based on the interfacial wettability weighting coefficient of the mineral component and the second classification criterion.

6. The method for analyzing the occurrence morphology of pore water in coal seams as described in claim 5, characterized in that, The process of determining the first and second partitioning datums includes: A benchmark pore model composed of the preset benchmark minerals is constructed, water molecules are introduced into the benchmark pore model, and molecular dynamics simulation is performed until the system reaches statistical steady state. The dynamic binding strength index of a single water molecule at different positions during the steady-state simulation phase was collected to obtain the continuous decay distribution curve of the binding strength. Based on the distribution inflection point characteristics of the continuous decay distribution curve of the binding strength, the dynamic binding strength index of a single water molecule corresponding to the boundary position between adsorbed water and thin film water is extracted as the first dividing criterion. Based on another distribution inflection point feature of the continuous decay distribution curve of the binding strength, the dynamic binding strength index of a single water molecule corresponding to the boundary position between the thin film water and free water is extracted as the second dividing criterion.

7. The method for analyzing the occurrence morphology of pore water in coal seams as described in claim 1, characterized in that, The construction process of the target mineral coupling model includes: Obtain the mineral components and the proportion of each mineral component in the target coal sample; For each mineral component, the thickness of the mineral layer corresponding to that mineral component is determined based on its proportion. Based on the thickness of the mineral layers corresponding to each mineral component, the target mineral coupling model is constructed in a horizontally single mineral layer stacking manner.

8. A device for analyzing the occurrence morphology of pore water in coal seams, characterized in that, include: The data acquisition module is used to acquire the mineral components and pore size distribution of each mineral component in the target coal sample after the experiment is conducted on the target coal sample, and to acquire the target mineral coupling model corresponding to the target coal sample; the target mineral coupling model is constructed using a horizontal single mineral layer stacking method; The mineral component characteristic determination module is used to determine the interfacial wettability weight coefficient of each mineral component, and to determine the equivalent pore size of the mineral component based on its pore size distribution. The interface wettability weighting coefficient is used to characterize the inherent water adsorption capacity of the mineral lattice surface of the corresponding mineral component. The simulation evolution module is used to introduce methane molecules and water molecules into the target mineral coupling model so that the target mineral coupling model can perform molecular dynamics simulation evolution and obtain the position of water molecules at each time point during the evolution process and the occupancy rate of methane molecules on the adsorption sites of each mineral component at each time point. The morphology determination module is used to determine the dynamic binding strength index of a single water molecule for each water molecule that is released, based on the interfacial wettability weight coefficient of each mineral component, the equivalent pore size of each mineral component, the position of the water molecule at each time, and the occupancy rate of the adsorption sites of methane molecules on the surface of each mineral component at each time. Based on the dynamic binding strength index of the single water molecule and the mineral components, the morphology of the water molecule is determined. The dynamic binding strength index of the single water molecule is used to characterize the degree to which the corresponding water molecule is bound by each mineral component at each time.

9. An electronic device comprising a memory, a processor, and a computer program stored in the memory and running on the processor, characterized in that, When the processor executes the computer program, it implements the steps of 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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