Method, system and equipment for determining migration law of fluid in porous medium

Abstract

The invention discloses a method, a system and equipment for determining a migration rule of fluid in a porous medium. The method for determining the migration rule of the fluid in the porous medium comprises the following steps: obtaining the porous medium, and measuring to obtain a nuclear magnetic resonance relaxation spectrum of the porous medium; the quantitative relation between the saturation degree of the liquid in the pores and the nuclear magnetic resonance relaxation spectrum under the corresponding liquid state is obtained, and the quantitative relation is determined according to the nuclear magnetic resonance relaxation spectrum of the liquid under the different liquid saturation degrees and the corresponding liquid saturation degrees of the micro-model of the porous structure; and according to the nuclear magnetic resonance relaxation spectrum of the porous medium and the quantitative relationship, determining the occurrence state of the fluid in the porous medium and the fluid migration law. By adopting the method and the device, the occurrence state of the fluid in the porous pores can be accurately obtained, and then important guiding significance is brought for obtaining the fluid migration rule in a porous multiphase system.

Description

Technical Field

[0001] The present application relates to the technical field of heat and mass transport in porous media, and in particular to a method, system and device for determining the migration law of fluid in porous media. Background Art

[0002] The fluid transport process inside porous media materials is widely present in many engineering fields such as aerospace, construction engineering, and underground oil and gas extraction. Due to the influence of many factors such as the pore size of porous materials and the interaction of phase interfaces, the fluid transport mechanism inside porous materials is complex. Obtaining the occurrence state and migration law of liquids inside pores is crucial for a deep understanding of the fluid transport process inside porous media. The complex solid skeleton and pore network of porous materials make it difficult to directly observe the fluid behavior inside porous media using general experimental methods. Low-field nuclear magnetic resonance measurement technology is a powerful means of non-destructive characterization of hydrogen-containing fluids inside porous media. It can obtain the interaction between moisture and pores by measuring the hydrogen atom relaxation process, and can therefore be used to study the structure of porous media and the transport of different types of liquids inside them. However, existing nuclear magnetic resonance measurement and analysis methods are only based on the assumption that the liquid in the pores is saturated and the liquid relaxation between pores is independent of each other. The measured relaxation spectrum is directly corresponded to the pore size distribution of the liquid. However, it does not take into account the influence of complex factors such as partial saturation of liquid in the pores and mutual coupling of liquid relaxation in multi-scale pores in actual porous multiphase systems on the measured nuclear magnetic relaxation spectrum. Therefore, it is difficult to directly analyze the liquid morphology in porous materials through nuclear magnetic measurements based on the existing nuclear magnetic relaxation spectrum analysis methods, and then analyze the liquid migration characteristics in complex porous systems.

[0003] Obtaining the state of liquid within pores is crucial for a deeper understanding of fluid migration within porous media. Low-field nuclear magnetic resonance (NMR), a measurement technique that can non-destructively characterize hydrogen-containing fluids within porous frameworks, has been applied in numerous engineering fields involving fluid migration within porous materials, such as soil seepage and underground oil and gas extraction. However, existing NMR analysis methods are based solely on the assumption that the pores are saturated with liquid and that the relaxation of liquids between pores is independent of each other. They directly correlate the measured transverse relaxation time spectra with the pore diameter distribution of the liquid within the porous material. However, these methods fail to consider the influence of complex factors such as partial saturation of liquid within pores and the coupling of liquid relaxations at multiple scales within pores in actual porous multiphase systems on the measured NMR relaxation spectra. Therefore, it is difficult to directly correlate NMR measurement results with the liquid morphology within porous materials using existing NMR analysis methods, making it difficult to analyze the liquid migration characteristics within complex porous systems. Summary of the Invention

[0004] Based on this, it is necessary to provide a method, system and equipment for determining the migration law of fluid in porous media to address the above technical problems. By directly observing the liquid morphology in the microscopic model and measuring its nuclear magnetic resonance relaxation spectrum, a quantitative relationship between the pore-scale liquid morphology and the nuclear magnetic resonance relaxation spectrum can be established, which is of great guiding significance for analyzing the fluid storage state inside porous pores through nuclear magnetic resonance experiments, and then obtaining the fluid migration law in porous multiphase systems.

[0005] In a first aspect, the present application provides a method for determining the migration law of fluid in a porous medium, comprising:

[0006] obtaining a porous medium, and measuring a nuclear magnetic resonance relaxation spectrum of the porous medium;

[0007] Obtaining a quantitative relationship between the liquid saturation in the pores and the nuclear magnetic resonance relaxation spectrum under the corresponding liquid state, wherein the quantitative relationship is determined based on the nuclear magnetic resonance relaxation spectrum of the liquid at different liquid saturations and the corresponding liquid saturation according to the microscopic model of the designed porous structure;

[0008] The fluid occurrence state and fluid migration law in the porous medium are determined based on the nuclear magnetic resonance relaxation spectrum of the porous medium and the quantitative relationship.

[0009] In some examples, obtaining a quantitative relationship between the liquid saturation in the pores and the nuclear magnetic resonance relaxation spectrum under the corresponding liquid state includes:

[0010] Designing a visual micro-model, wherein the visual micro-model includes a desired porous medium pore structure;

[0011] Obtaining the liquid distribution state required by the internal pores of the microscopic model and measuring the liquid morphology in the internal pores of the microscopic model;

[0012] When the pores inside the microscopic model reach a desired liquid distribution state, obtaining a nuclear magnetic resonance relaxation spectrum of the liquid in the microscopic model;

[0013] According to the liquid form in the pores of the microscopic model and the corresponding nuclear magnetic resonance relaxation spectrum, a quantitative relationship between the liquid saturation in the pores and the nuclear magnetic resonance relaxation spectrum under the corresponding liquid form is determined.

[0014] In some examples, obtaining the liquid distribution state required by the pores within the microscopic model and measuring the liquid morphology in the pores within the microscopic model includes:

[0015] When the pores inside the microscopic model reach a desired liquid distribution state, observing the microscopic model under an optical microscope and scanning and capturing an image;

[0016] The liquid morphology in the internal pores of the microscopic model is obtained based on the captured images.

[0017] In some examples, determining the quantitative relationship between the liquid saturation in the pores and the nuclear magnetic resonance relaxation spectrum under the corresponding liquid morphology based on the liquid morphology in the pores of the microscopic model and the corresponding nuclear magnetic resonance relaxation spectrum includes:

[0018] The correspondence between the relaxation spectrum peak in the nuclear magnetic resonance relaxation spectrum and the liquid saturation in the microscopic model pores under the corresponding liquid form is analyzed to determine the quantitative relationship between the liquid saturation in the pores and the nuclear magnetic resonance relaxation spectrum under the corresponding liquid form based on the correspondence.

[0019] In some examples, the correspondence between the relaxation spectrum peak in the nuclear magnetic resonance relaxation spectrum and the liquid saturation in the pores of the microscopic model under the corresponding liquid state is obtained by the following formula:

[0020]

[0021] Wherein, T2 is the peak of the relaxation spectrum in the nuclear magnetic resonance relaxation spectrum, the peak of the relaxation spectrum corresponds to T2, s is the liquid saturation in the pores of the microscopic model, and T 2,b is the bulk transverse relaxation time of the liquid, which is an intrinsic property of the liquid; ρ is the surface relaxation rate of the pores inside the porous material, which is an intrinsic property of the solid material, S p is the pore surface area, V p is the pore volume.

[0022] In some examples, the liquid saturation includes a liquid saturation state and a liquid partial saturation state. Accordingly, the nuclear magnetic resonance relaxation spectrum includes a nuclear magnetic resonance relaxation spectrum in a liquid saturation state and a nuclear magnetic resonance relaxation spectrum in a liquid partial saturation state.

[0023] In some examples, determining the fluid state and fluid migration pattern in the porous medium based on the nuclear magnetic resonance relaxation spectrum of the porous medium and the quantitative relationship includes:

[0024] determining the fluid morphology of the fluid in the porous medium according to the nuclear magnetic resonance relaxation spectrum of the porous medium and the quantitative relationship;

[0025] According to the fluid morphology of the fluid in the porous medium, the occurrence state of the fluid in the porous medium and the fluid migration law are obtained.

[0026] In a second aspect, a system for determining the migration law of fluid in a porous medium is provided, comprising:

[0027] A measurement module, configured to obtain a porous medium and measure a nuclear magnetic resonance relaxation spectrum of the porous medium;

[0028] a relationship acquisition module for obtaining a quantitative relationship between the liquid saturation in the pores and the nuclear magnetic resonance relaxation spectrum under the corresponding liquid form, wherein the quantitative relationship is determined based on the nuclear magnetic resonance relaxation spectrum of the liquid at different liquid saturations and the corresponding liquid saturation according to the microscopic model of the designed porous structure;

[0029] The determination module is used to determine the fluid occurrence state and fluid migration law in the porous medium according to the nuclear magnetic resonance relaxation spectrum of the porous medium and the quantitative relationship.

[0030] In a third aspect, a computer device is provided, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the program, the steps of the method for determining the fluid migration law in a porous medium according to the first aspect and any possible implementation of the first aspect are implemented.

[0031] In a fourth aspect, a computer-readable storage medium is provided, on which a computer program is stored. When the program is executed by a processor, the steps of the method for determining the fluid migration law in a porous medium according to the first aspect and any possible implementation of the first aspect are implemented.

[0032] By using the embodiments of the present application, by directly observing the liquid morphology in the microscopic model and measuring its nuclear magnetic resonance relaxation spectrum, a quantitative relationship between the pore-scale liquid morphology and the nuclear magnetic resonance relaxation spectrum can be established, which has important guiding significance for analyzing the fluid storage state inside porous pores through nuclear magnetic resonance experiments, and then obtaining the fluid migration law in porous multiphase systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Other features, objects and advantages of the present application will become more apparent upon reading the detailed description of non-limiting embodiments made with reference to the following drawings:

[0034] Figure 1 This is a flow chart of a method for determining the migration law of fluid in a porous medium provided in an embodiment of the present application;

[0035] Figure 2 A schematic diagram of a microscopic model provided in an embodiment of the present application;

[0036] Figure 3 Schematic diagram of the liquid morphology inside the pores of the microscopic model provided in the examples of this application;

[0037] Figure 4 Schematic diagram of nuclear magnetic resonance relaxation spectra obtained by measuring microscopic models of different states in the embodiments of the present application;

[0038] Figure 5 This is a structural block diagram of a system for determining the migration law of fluid in a porous medium provided in an embodiment of the present application;

[0039] Figure 6 This is a structural block diagram of the computer device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0040] The present application will be further described in detail below with reference to the embodiments and accompanying drawings. It should be understood that the specific embodiments described herein are intended only to illustrate the relevant application and are not intended to limit the application. It should also be noted that, for ease of description, only the portions relevant to the application are shown in the accompanying drawings.

[0041] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments in this application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0042] The following describes in detail the method, system, and apparatus for determining the migration law of fluid in a porous medium according to an embodiment of the present application in conjunction with the accompanying drawings.

[0043] The method, system and device for determining the migration law of fluid in porous media of the present application solve the technical problem of inaccurate determination of the migration law of fluid in porous media in related technologies.

[0044] Figure 1 FIG. 1 is a flow chart of a method for determining the migration law of fluid in a porous medium according to an embodiment of the present application. Figure 1 As shown, the method for determining the migration law of fluid in a porous medium according to an embodiment of the present application includes the following steps:

[0045] S101: obtaining a porous medium, and measuring a nuclear magnetic resonance relaxation spectrum of the porous medium.

[0046] S102: Obtaining a quantitative relationship between the liquid saturation in the pores and the nuclear magnetic resonance relaxation spectrum under the corresponding liquid form, wherein the quantitative relationship is determined based on the nuclear magnetic resonance relaxation spectrum of the liquid at different liquid saturations and the corresponding liquid saturation according to the microscopic model of the designed porous structure.

[0047] In one embodiment of the present application, obtaining a quantitative relationship between the liquid saturation in the pores and the nuclear magnetic resonance relaxation spectrum under the corresponding liquid form includes: designing a visual micromodel, wherein the visual micromodel includes the required porous medium pore structure; obtaining the required liquid distribution state of the pores inside the micromodel, and measuring the liquid form in the pores inside the micromodel; when the pores inside the micromodel reach the required liquid distribution state, obtaining the nuclear magnetic resonance relaxation spectrum of the liquid in the micromodel; and determining the quantitative relationship between the liquid saturation in the pores and the nuclear magnetic resonance relaxation spectrum under the corresponding liquid form based on the liquid form in the pores inside the micromodel and the corresponding nuclear magnetic resonance relaxation spectrum.

[0048] In this example, the required liquid distribution state of the internal pores of the micro model is obtained, and the liquid morphology in the internal pores of the micro model is measured, including: when the internal pores of the micro model reach the required liquid distribution state, the micro model is observed under an optical microscope and scanned to capture an image; based on the captured image, the liquid morphology in the internal pores of the micro model is obtained.

[0049] In this example, based on the liquid form in the pores inside the micromodel and the corresponding nuclear magnetic resonance relaxation spectrum, the quantitative relationship between the liquid saturation in the pores and the nuclear magnetic resonance relaxation spectrum under the corresponding liquid form is determined, including: analyzing the correspondence between the relaxation spectrum peak in the nuclear magnetic resonance relaxation spectrum and the liquid saturation in the pores of the micromodel under the corresponding liquid form, so as to determine the quantitative relationship between the liquid saturation in the pores and the nuclear magnetic resonance relaxation spectrum under the corresponding liquid form based on the correspondence.

[0050] As a specific example, a visual microscopic model can be made by silicon-based etching and glass bonding methods. The porous pore structure required for platemaking research is designed, and photoresist is applied on the silicon wafer. The pre-designed pore structure is obtained by dry etching, and it is anodically bonded to the glass sheet at high temperature and voltage to obtain a porous medium with controllable pore structure and size, and the liquid state inside the pores can be directly observed microscopically. At both ends of the designed pore structure, holes are punched from the bottom of the silicon wafer as fluid inlets and outlets, thereby realizing fluid injection inside the pores of the microscopic model. In one implementation method, different pore sizes, pore shapes and connectivity designs, as well as a combination of multiple microscopic models with different designs, can be used to achieve an approximate simulation of the pore structure of complex porous materials, thereby obtaining a more complex liquid distribution inside the pores.

[0051] The desired liquid distribution state within the pores of the microscopic model is obtained, and microscopic observation experiments are conducted to measure the liquid morphology within the pores. Specifically, for example, a clamp and tubing are used to clamp the fluid inlet and outlet at the bottom of the microscopic model, and liquid is injected into the interior through the inlet. First, a microscopic model with liquid-saturated pores is obtained. Based on the liquid-saturated microscopic model, the liquid in the microscopic model can be partially discharged by heating the model and introducing dry gas into the model, thereby obtaining a gas-liquid two-phase state within the pores for the desired study.

[0052] When the desired liquid state is achieved within the porous structure of the micromodel, the micromodel is observed under an optical microscope and scanned and captured. The captured images are processed using image processing software to measure the liquid morphology within the micromodel's pores in the corresponding state. The micromodel or combination of micromodels in this state is then placed in a low-field nuclear magnetic resonance (NMR) instrument and measured using a Carr-Purcell-Meiboom-Gill (CPMG) sequence to obtain the transverse relaxation time T2 spectrum (i.e., NMR relaxation spectrum) of the liquid within the micromodel. Using the visualized micromodel as a medium, the pore-scale liquid morphology and the NMR relaxation spectrum are jointly measured, and a direct correspondence between the two is established. This helps to establish a quantitative relationship between the measured NMR relaxation spectrum T2 and the liquid state within the pores of porous media, providing guidance for analyzing the occurrence and migration of liquids within porous materials through NMR experiments.

[0053] For example, liquid saturation includes liquid saturation state and liquid partial saturation state. Correspondingly, the nuclear magnetic resonance relaxation spectrum includes the nuclear magnetic resonance relaxation spectrum in the liquid saturation state and the nuclear magnetic resonance relaxation spectrum in the liquid partial saturation state. Then, a direct connection between the liquid saturation inside the porous pores and the nuclear magnetic transverse relaxation time T2 can be established, and its quantitative law can be obtained. A circular pore array arrangement structure with a diameter of 400 μm, uniform distribution, and interconnectedness is designed. The structure is plated and the silicon wafer is dry-etched to a depth of 400 μm. Holes are punched from the bottom of the silicon wafer as fluid inlets and outlets. The above silicon wafer is bonded to a glass anode to obtain a visual porous microscopic model with a single pore characteristic scale of 400 μm and uniform pore distribution. The pore structure of the microscopic model is as follows: Figure 2 shown.

[0054] The above-mentioned micromodel is loaded with a holder, and liquid water is introduced into the micromodel from the bottom inlet until the liquid water is fully injected, thereby obtaining a micromodel whose pores are in a liquid water saturated state. The saturated micromodel is loaded into a sample holder and placed in a low-field nuclear magnetic resonance device, and its transverse relaxation time T2 spectrum is measured using a CPMG sequence. Subsequently, dry nitrogen is introduced into the interior of the micromodel using a holder to discharge the liquid water in the saturated pores of the micromodel, so that the pores are in a liquid unsaturated state and the liquid distribution between the pores is roughly uniform. The fluid morphology inside the pores is observed and photographed under an optical microscope, and the photographed images are binarized using the image processing software Fiji to obtain the liquid morphology inside the pores of the micromodel and the average saturation of the liquid in the pores, as shown in FIG. Figure 3 shown.

[0055] Furthermore, by continuing to introduce dry nitrogen into the microscopic model to gradually evaporate and reduce the internal liquid water, a microscopic model with different liquid saturations in the pores can be obtained. For the microscopic model with different liquid saturations in the pores obtained by the above method, the CPMG sequence is used to perform nuclear magnetic resonance measurement to obtain the nuclear magnetic T2 spectrum corresponding to the liquid saturation in the pores, and the spectrum is compared with the nuclear magnetic T2 spectrum of the liquid saturation state, as shown in FIG. Figure 4 As shown. By analyzing the relaxation spectrum peak T2 obtained by nuclear magnetic resonance measurement and the liquid saturation s in the microscopic model pores under the corresponding state, the corresponding relationship between T2 and s is obtained:

[0056]

[0057] Wherein, T2 is the relaxation spectrum peak in the nuclear magnetic resonance relaxation spectrum, and the relaxation spectrum peak corresponds to T2, T 2,b is the bulk transverse relaxation time of the liquid, which is an intrinsic property of the liquid; ρ is the surface relaxation rate of the pores inside the porous material, which is an intrinsic property of the solid material; S p is the pore surface area, V p is the pore volume, which can be obtained through material characterization. Therefore, by combining the above-mentioned microscopic model pore-scale liquid state and nuclear magnetic resonance relaxation spectrum measurement method, a quantitative relationship between the liquid saturation in the pore and the corresponding state nuclear magnetic relaxation spectrum T2 was established.

[0058] S103: Determine the fluid occurrence state and fluid migration law in the porous medium according to the nuclear magnetic resonance relaxation spectrum of the porous medium and the quantitative relationship.

[0059] Specifically, the fluid state and fluid migration patterns within the porous medium are determined based on the NMR relaxation spectrum of the porous medium and the quantitative relationship, including: determining the fluid morphology of the fluid within the porous medium based on the NMR relaxation spectrum of the porous medium and the quantitative relationship; and obtaining the fluid state and fluid migration patterns within the porous medium based on the fluid morphology of the fluid within the porous medium. This has guiding significance for analyzing and obtaining the fluid state and migration patterns in porous multiphase systems through NMR experiments.

[0060] The embodiments of the present application realize the direct connection between the liquid inside the pores of the porous medium and the nuclear magnetic resonance relaxation spectrum measured by the corresponding state, breaking through the limitation of the existing nuclear magnetic resonance analysis method that only explains the overall situation of the fluid in the solid skeleton and is difficult to reveal the fluid state in complex pores. It can help obtain the quantitative law between the nuclear magnetic resonance relaxation spectrum and the fluid information at the pore scale of the porous medium, and has guiding significance for analyzing the occurrence state and migration law of fluid in porous multiphase systems through nuclear magnetic resonance experiments.

[0061] In the embodiments of the present application, the pore-scale liquid information is rich. By making visual microscopic models of different pore sizes, structures and combinations, different morphologies of liquid in the pores can be obtained, and the liquid morphology can be directly observed and quantitatively described under an optical microscope. Compared with methods such as the gravimetric measurement of bulk porous materials, the pore-scale liquid information obtained is richer. Directly linking the morphology of liquid in the pores with the nuclear magnetic relaxation spectrum, that is: existing nuclear magnetic resonance measurements are mostly for bulk porous materials, which can only reflect the total package information of the liquid in the material; the present application directly establishes a connection between the morphology of liquid in the pores and the measured nuclear magnetic resonance relaxation spectrum, which can develop an explanation of the state of fluid at the porous pore scale based on the results of nuclear magnetic resonance measurements.

[0062] According to the method for determining the fluid migration law in porous media in the embodiment of the present application, by directly observing the liquid morphology in the microscopic model and measuring its nuclear magnetic resonance relaxation spectrum, a quantitative relationship between the pore-scale liquid morphology and the nuclear magnetic resonance relaxation spectrum can be established, which has important guiding significance for analyzing the fluid storage state inside porous pores through nuclear magnetic resonance experiments, and then obtaining the fluid migration law in porous multiphase systems.

[0063] Figure 5 FIG. 1 is a structural block diagram of a system for determining the migration law of fluid in a porous medium according to an embodiment of the present application. Figure 5 As shown, the system for determining the migration law of fluid in porous media according to an embodiment of the present application includes: a measurement module 510, a relationship acquisition module 520 and a determination module 530, wherein:

[0064] The measurement module 510 is used to obtain a porous medium and measure a nuclear magnetic resonance relaxation spectrum of the porous medium;

[0065] a relationship acquisition module 520 for obtaining a quantitative relationship between the liquid saturation in the pores and the nuclear magnetic resonance relaxation spectrum of the corresponding liquid form, wherein the quantitative relationship is determined based on the designed microscopic model of the porous structure at different liquid saturations and the nuclear magnetic resonance relaxation spectrum of the liquid at the corresponding liquid saturation;

[0066] The determination module 530 is configured to determine the fluid occurrence state and fluid migration law in the porous medium according to the nuclear magnetic resonance relaxation spectrum of the porous medium and the quantitative relationship.

[0067] According to the system for determining the fluid migration law in porous media in the embodiment of the present application, by directly observing the liquid morphology in the microscopic model and measuring its nuclear magnetic resonance relaxation spectrum, a quantitative relationship between the pore-scale liquid morphology and the nuclear magnetic resonance relaxation spectrum can be established, which has important guiding significance for analyzing the fluid storage state inside porous pores through nuclear magnetic resonance experiments, and then obtaining the fluid migration law in porous multiphase systems.

[0068] The specific definition of the system for determining the migration law of fluid in porous media can be found in the definition of the method for determining the migration law of fluid in porous media described above, and will not be repeated here. The various modules of the system for determining the migration law of fluid in porous media described above can be implemented in whole or in part through software, hardware, or a combination thereof. The above modules can be embedded in or independent of the processor in the computer device in the form of hardware, or can be stored in the memory of the computer device in the form of software, so that the processor can call and execute the operations corresponding to the above modules.

[0069] In one embodiment, a computer device is provided. Figure 6 This is a block diagram of the computer device provided in an embodiment of the present application. The computer device includes a memory and a processor. The memory stores a computer program. When the processor executes the computer program, it implements the aforementioned method for determining the migration pattern of fluid in a porous medium. For example, the method may include: obtaining a porous medium and measuring a nuclear magnetic resonance relaxation spectrum of the porous medium;

[0070] Obtaining a quantitative relationship between the liquid saturation in the pores and the nuclear magnetic resonance relaxation spectrum under the corresponding liquid state, wherein the quantitative relationship is determined based on the nuclear magnetic resonance relaxation spectrum of the liquid at different liquid saturations and the corresponding liquid saturation according to the microscopic model of the designed porous structure;

[0071] The fluid occurrence state and fluid migration law in the porous medium are determined based on the nuclear magnetic resonance relaxation spectrum of the porous medium and the quantitative relationship.

[0072] The present application also provides a computer-readable storage medium storing a computer program, wherein a processor executes the computer program to implement the aforementioned method for determining the migration law of fluid in a porous medium. For example, the method may include: obtaining a porous medium and measuring a nuclear magnetic resonance relaxation spectrum of the porous medium;

[0073] Obtaining a quantitative relationship between the liquid saturation in the pores and the nuclear magnetic resonance relaxation spectrum under the corresponding liquid state, wherein the quantitative relationship is determined based on the nuclear magnetic resonance relaxation spectrum of the liquid at different liquid saturations and the corresponding liquid saturation according to the microscopic model of the designed porous structure;

[0074] The fluid occurrence state and fluid migration law in the porous medium are determined based on the nuclear magnetic resonance relaxation spectrum of the porous medium and the quantitative relationship.

[0075] The present application embodiment provides a computer program product, which includes instructions. When the instructions are executed, the method described in the embodiment of the present application is executed. For example, you can execute Figure 1 The steps of the method for determining the migration law of fluid in a porous medium are, for example, performed as follows: obtaining a porous medium and measuring a nuclear magnetic resonance relaxation spectrum of the porous medium;

[0076] Obtaining a quantitative relationship between the liquid saturation in the pores and the nuclear magnetic resonance relaxation spectrum under the corresponding liquid state, wherein the quantitative relationship is determined based on the nuclear magnetic resonance relaxation spectrum of the liquid at different liquid saturations and the corresponding liquid saturation according to the microscopic model of the designed porous structure;

[0077] The fluid occurrence state and fluid migration law in the porous medium are determined based on the nuclear magnetic resonance relaxation spectrum of the porous medium and the quantitative relationship.

[0078] Those skilled in the art will appreciate that all or part of the processes in the methods for implementing the above embodiments can be accomplished by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include processes of the embodiments of the above methods. Among them, any reference to memory, storage, database or other media used in the embodiments provided in this application may include at least one of non-volatile and volatile memory. Non-volatile memory may include read-only memory (ROM), magnetic tape, floppy disk, flash memory or optical memory, etc. Volatile memory may include random access memory (RAM) or external cache memory. As an illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM).

[0079] The technical features of the above embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0080] The above embodiments merely illustrate several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that a person of ordinary skill in the art may make various modifications and improvements without departing from the spirit of the present application, all of which fall within the scope of protection of the present application. Therefore, the scope of protection of the present patent application shall be determined by the appended claims.

Claims

1. A method for determining the migration law of fluid in porous media, characterized in that: include: obtaining a porous medium, and measuring a nuclear magnetic resonance relaxation spectrum of the porous medium; Obtaining a quantitative relationship between the liquid saturation in the pores and the nuclear magnetic resonance relaxation spectrum under the corresponding liquid state, wherein the quantitative relationship is determined based on the nuclear magnetic resonance relaxation spectrum of the liquid at different liquid saturations and the corresponding liquid saturation according to the microscopic model of the designed porous structure; The fluid occurrence state and fluid migration law in the porous medium are determined based on the nuclear magnetic resonance relaxation spectrum of the porous medium and the quantitative relationship.

2. The method for determining the migration law of fluid in porous media according to claim 1, characterized in that: The method of obtaining a quantitative relationship between the liquid saturation in the pores and the nuclear magnetic resonance relaxation spectrum under the corresponding liquid state includes: Designing a visual micro-model, wherein the visual micro-model includes a desired porous medium pore structure; Obtaining the liquid distribution state required by the internal pores of the microscopic model and measuring the liquid morphology in the internal pores of the microscopic model; When the pores inside the microscopic model reach a desired liquid distribution state, obtaining a nuclear magnetic resonance relaxation spectrum of the liquid in the microscopic model; According to the liquid form in the pores of the microscopic model and the corresponding nuclear magnetic resonance relaxation spectrum, a quantitative relationship between the liquid saturation in the pores and the nuclear magnetic resonance relaxation spectrum under the corresponding liquid form is determined.

3. The method for determining the migration law of fluid in porous media according to claim 2, characterized in that: The obtaining of the liquid distribution state required for the internal pores of the microscopic model and measuring the liquid morphology in the internal pores of the microscopic model includes: When the pores inside the microscopic model reach a desired liquid distribution state, observing the microscopic model under an optical microscope and scanning and capturing an image; The liquid morphology in the internal pores of the microscopic model is obtained based on the captured images.

4. The method for determining the migration law of fluid in porous media according to claim 3, characterized in that: Determining the quantitative relationship between the liquid saturation in the pores and the nuclear magnetic resonance relaxation spectrum under the corresponding liquid morphology based on the liquid morphology in the pores of the microscopic model and the corresponding nuclear magnetic resonance relaxation spectrum includes: The correspondence between the relaxation spectrum peak in the nuclear magnetic resonance relaxation spectrum and the liquid saturation in the microscopic model pores under the corresponding liquid form is analyzed to determine the quantitative relationship between the liquid saturation in the pores and the nuclear magnetic resonance relaxation spectrum under the corresponding liquid form based on the correspondence.

5. The method for determining the migration law of fluid in porous media according to claim 4, characterized in that: The corresponding relationship between the relaxation spectrum peak in the nuclear magnetic resonance relaxation spectrum and the liquid saturation in the pores of the microscopic model under the corresponding liquid state is obtained by the following formula: Wherein, T2 is the peak of the relaxation spectrum in the nuclear magnetic resonance relaxation spectrum, the peak of the relaxation spectrum corresponds to T2, s is the liquid saturation in the pores of the microscopic model, and T 2,b is the bulk transverse relaxation time of the liquid, which is an intrinsic property of the liquid; ρ is the surface relaxation rate of the pores inside the porous material, which is an intrinsic property of the solid material, S p is the pore surface area, V p is the pore volume.

6. The method for determining the migration law of fluid in porous media according to claim 4 or 5, characterized in that: The liquid saturation includes a liquid saturation state and a liquid partial saturation state. Correspondingly, the nuclear magnetic resonance relaxation spectrum includes a nuclear magnetic resonance relaxation spectrum in a liquid saturation state and a nuclear magnetic resonance relaxation spectrum in a liquid partial saturation state.

7. The method for determining the migration law of fluid in porous media according to claim 1, characterized in that: Determining the fluid state and fluid migration law in the porous medium based on the nuclear magnetic resonance relaxation spectrum of the porous medium and the quantitative relationship includes: determining the fluid morphology of the fluid in the porous medium according to the nuclear magnetic resonance relaxation spectrum of the porous medium and the quantitative relationship; According to the fluid morphology of the fluid in the porous medium, the occurrence state of the fluid in the porous medium and the fluid migration law are obtained.

8. A system for determining the migration law of fluid in porous media, characterized in that: include: A measurement module, configured to obtain a porous medium and measure a nuclear magnetic resonance relaxation spectrum of the porous medium; a relationship acquisition module for obtaining a quantitative relationship between the liquid saturation in the pores and the nuclear magnetic resonance relaxation spectrum under the corresponding liquid form, wherein the quantitative relationship is determined based on the nuclear magnetic resonance relaxation spectrum of the liquid at different liquid saturations and the corresponding liquid saturation according to the microscopic model of the designed porous structure; The determination module is used to determine the fluid occurrence state and fluid migration law in the porous medium according to the nuclear magnetic resonance relaxation spectrum of the porous medium and the quantitative relationship.

9. A computer device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the program, the method for determining the migration law of fluid in a porous medium according to any one of claims 1 to 7 is implemented.

10. A computer-readable storage medium comprising a memory and a computer program stored in the memory and executable on a processor, characterized in that: When the program is executed by a processor, the method for determining the migration law of fluid in a porous medium according to any one of claims 1 to 7 is implemented.

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