Method and system for evaluating maximum hydrogen storage potential of exhausted shale gas reservoir

Abstract

The invention provides a method and a system for evaluating the maximum hydrogen storage potential of an exhausted shale gas reservoir, and belongs to the technical field of new energy hydrogen storage research. According to the method, the actual condition and various influence factors of the multi-stage fractured horizontal well are comprehensively considered, the result is more reliable, meanwhile, the maximum storage potential of hydrogen under different constraint pressures is obtained through a pseudo-pressure calculation method based on the pull-type transformation technology and the Bezier function theory, the calculation process is simplified, and the calculation efficiency is improved. The hydrogen storage potential in the exhausted shale gas reservoir is rapidly and accurately evaluated, and the evaluation is more efficient and accurate.

Description

Technical Field

[0001] The present invention relates to the technical field of new energy hydrogen storage research, and in particular to a method and system for evaluating the maximum hydrogen storage potential of a depleted shale gas reservoir. Background Art

[0002] The successful transition from fossil energy to green renewable energy is one of the key technical approaches to mitigate global warming and achieve my country's "dual carbon goals". To achieve this goal, it is necessary to switch from reliance on fossil fuels to the use of clean, renewable energy such as solar, wind and tidal energy. However, the dependence of these energy sources on time, season, climate and geographical location limits their stability and reliability. Underground hydrogen storage technology provides an innovative solution. When there is an oversupply of energy, renewable energy is converted into hydrogen through water electrolysis and stored underground, and extracted and used during peak demand. However, due to the low mass density of hydrogen, extremely large storage space is required to achieve large-scale hydrogen storage. Ground storage equipment (such as pipelines and gas tanks) has limited energy storage and cannot meet the significant needs of large-scale hydrogen economic development.

[0003] Underground storage space has large energy storage and high safety, making it an ideal place for large-scale hydrogen storage. Among them, depleted shale gas reservoirs have the advantages of large storage space, anaerobic environment inside, good sealing conditions, and reusable ground and underground facilities. The promotion and application of underground hydrogen storage technology provides an efficient and sustainable solution for global energy transformation. The hydrogen storage capacity of depleted shale gas reservoirs is a key indicator for evaluating the construction of underground hydrogen storage, which determines the stability and reliability of energy supply.

[0004] In the existing technology, the material balance method uses an ideal storage tank model to evaluate the hydrogen storage potential of depleted oil and gas reservoirs, but it ignores the flow and complex transmission mechanism of hydrogen in the reservoir; although the numerical simulation method can study the hydrogen transport mechanism in underground porous media and evaluate the storage potential of hydrogen, the numerical simulation method requires a large amount of computing resources and geological data; although the analytical method is simple and convenient, there is currently no hydrogen storage potential evaluation model that simultaneously considers the multiple transmission mechanisms of hydrogen in the hydrogen storage process of depleted shale gas reservoirs, complex fracture networks, and multi-well factory development conditions. Summary of the invention

[0005] In order to solve the above problems in the prior art, the present invention provides a method and system for evaluating the maximum hydrogen storage potential of depleted shale gas reservoirs. The invention establishes a physical model and a mathematical model for evaluating the maximum hydrogen storage potential of multi-stage fractured horizontal wells in depleted shale gas reservoirs, based on the Las Vegas transformation technology and Bessel function theory, and through a pseudo-pressure calculation method, obtains the maximum storage potential of hydrogen under different constraint pressures, thereby realizing a rapid and accurate evaluation of the hydrogen storage potential in depleted shale gas reservoirs. To achieve the above purpose, the technical solution is as follows:

[0006] In one aspect, the present invention provides a method for evaluating the maximum hydrogen storage potential of a depleted shale gas reservoir, the method comprising:

[0007] S1. Based on the geological parameters and fluid physical parameters of depleted shale gas reservoirs, a physical model for evaluating the maximum hydrogen storage potential of multi-stage fractured horizontal wells in depleted shale gas reservoirs is established;

[0008] S2. Obtaining a mathematical model for evaluating the maximum hydrogen storage potential of multi-stage fractured horizontal wells in depleted shale gas reservoirs based on the physical model for evaluating the maximum hydrogen storage potential of multi-stage fractured horizontal wells in depleted shale gas reservoirs;

[0009] S3. Based on the mathematical model for evaluating the maximum hydrogen storage potential of multi-stage fractured horizontal wells in the depleted shale gas reservoir, the bottom hole pseudo-pressure solution in the Latten space is obtained based on the Latten transformation technology and Bessel function theory;

[0010] S4. Based on the bottom hole pseudo-pressure solution in the pull-type space, the Stehfest numerical inversion method is used to obtain the pseudo-pressure solution of the multi-stage fractured horizontal well in the depleted shale gas reservoir in the real domain;

[0011] S5. According to the pseudo-pressure solution of the multi-stage fractured horizontal well in the depleted shale gas reservoir in the real domain, the bottom hole pressure change of the multi-stage fractured horizontal well in the depleted shale gas reservoir during the hydrogen storage process is obtained by using the pseudo-pressure calculation method;

[0012] S6. According to the bottom hole pressure change during the hydrogen storage process of the multi-stage fractured horizontal well in the depleted shale gas reservoir, the maximum storage potential of hydrogen under different constraint pressures is obtained through the hydrogen injection time under different constraint pressures.

[0013] Optionally, the conditions for establishing the physical model for evaluating the maximum hydrogen storage potential of multi-stage fractured horizontal wells in depleted shale gas reservoirs include:

[0014] Condition 1: The depleted shale gas reservoir is a dual-medium reservoir. The fluid flow in the natural fractures is assumed to be a single-phase supercritical hydrogen flow, and the gas flow in the matrix is ​​a diffusion flow caused by concentration difference.

[0015] Condition 2: The seepage field formed during the hydrogen storage process of depleted shale gas reservoirs is simplified into two seepage zones, which include: the fractured reformed zone with higher permeability near the bottom of the well and the original formation zone with lower permeability;

[0016] Condition 3: The shale reservoir of the depleted shale gas reservoir is of uniform quality and thickness and has uniform depletion pressure;

[0017] Condition 4: The shale reservoir of the depleted shale gas reservoir has a closed circular boundary in the horizontal direction, and the top and bottom interfaces of the shale reservoir of the depleted shale gas reservoir are assumed to be impermeable boundaries;

[0018] Condition 5: Hydrogen flows in a one-dimensional linear manner in a complex hydraulic fracture network;

[0019] Condition 6: The hydrogen injection rate of the depleted shale gas reservoir during the hydrogen storage process is constant.

[0020] Optionally, in S2, according to the physical model for evaluating the maximum hydrogen storage potential of multi-stage fractured horizontal wells in depleted shale gas reservoirs, a mathematical model for evaluating the maximum hydrogen storage potential of multi-stage fractured horizontal wells in depleted shale gas reservoirs is obtained, including:

[0021] S21, obtaining the comprehensive diffusion rate, gas pseudo-pressure and dimensionless variable according to the physical model for evaluating the maximum hydrogen storage potential of multi-stage fractured horizontal wells in the depleted shale gas reservoir;

[0022] S22. According to the comprehensive diffusivity, gas pseudo-pressure and dimensionless variables, through perturbation transformation, a dimensionless mathematical model of hydraulic fracture system, a mathematical model of dual medium matrix area, a mathematical model of dual medium natural fracture area and a mathematical model of closed boundary reservoir are obtained;

[0023] S23. Based on the dimensionless seepage mathematical model of hydraulic fracture system, the seepage mathematical model of dual-medium matrix zone, the seepage mathematical model of dual-medium natural fracture zone and the seepage mathematical model of closed boundary reservoir, the initial bars and internal and external boundary conditions are set to obtain the mathematical model for evaluating the maximum hydrogen storage potential of multi-stage fractured horizontal wells in depleted shale gas reservoirs.

[0024] Optionally, the calculation method of the comprehensive diffusion rate includes:

[0025]

[0026] Where D e Integrated diffusion coefficient, D m Molecular diffusion coefficient, D k Knudsen diffusion coefficient.

[0027] Optionally, the dimensionless variables include: dimensionless pseudo-pressure, dimensionless time, dimensionless distance, dimensionless wellbore storage coefficient, dimensionless stress sensitivity coefficient, dimensionless hydrogen injection rate, dimensionless hydraulic fracture conductivity, dimensionless comprehensive diffusion coefficient and dimensionless hydrogen concentration.

[0028] Optionally, the perturbation transformation method comprises:

[0029]

[0030] In the formula, m j,D is the reservoir pseudo pressure, ζ j,D is the dimensionless pseudo-pressure after perturbation transformation, α Dis the dimensionless stress sensitivity coefficient.

[0031] Optionally, in S3, according to the mathematical model for evaluating the maximum hydrogen storage potential of multi-stage fractured horizontal wells in depleted shale gas reservoirs, based on the Lassen transformation technology and Bessel function theory, a bottom hole pseudo-pressure solution in the Lassen space is obtained, including:

[0032] S31, according to the dimensionless seepage mathematical model of the hydraulic fracture system, by using the pull-type transformation technology, obtaining the dimensionless pseudo-pressure solution of the dimensionless seepage mathematical model of the hydraulic fracture system;

[0033] S32, according to the mathematical model of seepage in the dual medium matrix area, by using the Latent transformation technology, obtaining a dimensionless solution of the mathematical model of seepage in the dual medium matrix area;

[0034] S33, according to the mathematical model of seepage in the natural fracture zone of dual medium, by using the Latent transformation technology, a dimensionless solution of the mathematical model of seepage in the natural fracture zone of dual medium is obtained;

[0035] S34, according to the mathematical model of seepage in the closed boundary reservoir, by using the Lassen transformation technique and Bessel function theory, a dimensionless pseudo-pressure solution of the mathematical model of seepage in the closed boundary reservoir is obtained;

[0036] S35. Based on the dimensionless pseudo-pressure solution of the dimensionless seepage mathematical model of the hydraulic fracture system, the dimensionless solution of the seepage mathematical model of the dual-medium matrix zone, the dimensionless solution of the seepage mathematical model of the dual-medium natural fracture zone and the dimensionless pseudo-pressure solution of the seepage mathematical model of the closed boundary reservoir, the skin effect and the wellbore storage effect are considered to obtain the bottom hole pseudo-pressure solution in the pull space.

[0037] Optionally, in S4, according to the bottom hole pseudo-pressure solution in the pull-type space, a Stehfest numerical inversion method is used to obtain a pseudo-pressure solution for a multi-stage fractured horizontal well in a depleted shale gas reservoir in a real domain, including:

[0038] S41, according to the bottom hole pseudo-pressure solution in the Laplace space, through the Laplace inverse transformation, obtain the bottom hole pseudo-pressure solution after inverse transformation;

[0039] S42, according to the bottom hole pseudo-pressure solution after the inverse transformation, the dimensionless bottom hole pseudo-pressure solution is obtained by approximating the dimensionless zero-order perturbation solution;

[0040] S43. Based on the dimensionless pseudo-pressure solution of the bottom hole, the pseudo-pressure solution of the multi-stage fractured horizontal well in the depleted shale gas reservoir in the real domain is obtained.

[0041] Optionally, the pseudo-pressure calculation method includes:

[0042]

[0043] Where m is the bottom hole pressure during hydrogen storage in a multi-stage fractured horizontal well in a depleted shale gas reservoir, p is the pseudo-pressure solution of a multi-stage fractured horizontal well in a depleted shale gas reservoir in the real domain, and μ i is the viscosity of hydrogen at the ith pressure point, μ i-1 is the viscosity of hydrogen at the i-1th pressure point, Z i is the compressibility factor of hydrogen at the ith pressure point, Z i-1 is the compression factor of hydrogen at the i-1th pressure point, p i is the pressure value of the ith pressure point, p i-1 is the pressure value of the i-1th pressure point, and n is the total number of pressure points.

[0044] On the other hand, the present invention provides a system for evaluating the maximum hydrogen storage potential of a depleted shale gas reservoir, which is applied to a method for evaluating the maximum hydrogen storage potential of a depleted shale gas reservoir. The system comprises:

[0045] A physical model building module is used to build a physical model for evaluating the maximum hydrogen storage potential of multi-stage fractured horizontal wells in depleted shale gas reservoirs based on the geological parameters and fluid physical property parameters of the depleted shale gas reservoirs;

[0046] A mathematical model building module is used to obtain a mathematical model for evaluating the maximum hydrogen storage potential of multi-stage fractured horizontal wells in depleted shale gas reservoirs based on the physical model for evaluating the maximum hydrogen storage potential of multi-stage fractured horizontal wells in depleted shale gas reservoirs;

[0047] The first calculation module is used to obtain the bottom hole pseudo-pressure solution in the Lattices space based on the mathematical model for evaluating the maximum hydrogen storage potential of the multi-stage fractured horizontal well in the depleted shale gas reservoir, based on the Lattices transformation technology and Bessel function theory;

[0048] The second calculation module is used to obtain the pseudo-pressure solution of the multi-stage fractured horizontal well in the depleted shale gas reservoir in the real domain by using the Stehfest numerical inversion method according to the bottom hole pseudo-pressure solution in the pull-type space;

[0049] The third model module is used to obtain the bottom hole pressure change of the multi-stage fractured horizontal well in the depleted shale gas reservoir during the hydrogen storage process by using the pseudo-pressure calculation method according to the pseudo-pressure solution of the multi-stage fractured horizontal well in the depleted shale gas reservoir in the real domain;

[0050] The fourth calculation module is used to obtain the maximum storage potential of hydrogen under different constraint pressures according to the change of bottom hole pressure during the hydrogen storage process of the multi-stage fracturing horizontal well of the depleted shale gas reservoir and the hydrogen injection time under different constraint pressures.

[0051] Compared with the prior art, the technical solution of the present invention has at least the following beneficial effects:

[0052] On the one hand, the above scheme establishes a physical model and a mathematical model for evaluating the maximum hydrogen storage potential of multi-stage fractured horizontal wells in depleted shale gas reservoirs, comprehensively considering the actual situation and various influencing factors of multi-stage fractured horizontal wells, making the results more reliable. On the other hand, based on the Las Vegas transform technology and Bessel function theory, the maximum storage potential of hydrogen under different constraint pressures is obtained through the pseudo-pressure calculation method, which simplifies the calculation process and realizes the rapid and accurate evaluation of the hydrogen storage potential in depleted shale gas reservoirs, making the evaluation more efficient and accurate. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0054] Figure 1 is a flowchart of steps of an embodiment of a method for evaluating the maximum hydrogen storage potential of a depleted shale gas reservoir of the present invention;

[0055] Figure 2 It is a flowchart of the steps of establishing a mathematical model for evaluating the maximum hydrogen storage potential of a multi-stage fractured horizontal well in a depleted shale gas reservoir in an embodiment of the method for evaluating the maximum hydrogen storage potential of a depleted shale gas reservoir of the present invention;

[0056] Figure 3 It is a flow chart of the steps of obtaining the bottom hole pseudo-pressure solution under the pull-type space in the embodiment of the method for evaluating the maximum hydrogen storage potential of a depleted shale gas reservoir of the present invention;

[0057] Figure 4 It is a flow chart of the steps of obtaining the pseudo-pressure solution of a multi-stage fractured horizontal well in a depleted shale gas reservoir in a real domain in an embodiment of the method for evaluating the maximum hydrogen storage potential of a depleted shale gas reservoir of the present invention;

[0058] Figure 5 It is a schematic diagram of a physical model for evaluating the maximum hydrogen storage potential of a multi-stage fractured horizontal well in a depleted shale gas reservoir in an embodiment of the method for evaluating the maximum hydrogen storage potential of a depleted shale gas reservoir of the present invention;

[0059] Figure 6 is a curve diagram showing the relationship between pseudo-pressure and pressure in an embodiment of a method for evaluating the maximum hydrogen storage potential of a depleted shale gas reservoir of the present invention;

[0060] Figure 7 is a graph showing the relationship between gas injection time and confinement pressure in an embodiment of a method for evaluating the maximum hydrogen storage potential of a depleted shale gas reservoir of the present invention;

[0061] Figure 8is a curve diagram showing the relationship between the restraint pressure and the hydrogen storage volume in an embodiment of the method for evaluating the maximum hydrogen storage potential of a depleted shale gas reservoir of the present invention;

[0062] Fig. 9 It is a system block diagram of an embodiment of a system for evaluating the maximum hydrogen storage potential of a depleted shale gas reservoir according to the present invention. DETAILED DESCRIPTION

[0063] The technical solution of the present invention is described below in conjunction with the accompanying drawings.

[0064] In the embodiments of the present invention, words such as "exemplarily" and "for example" are used to indicate examples, illustrations or explanations. Any embodiment or design described as "example" in the present invention should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of the word "example" is intended to present the concept in a specific way. In addition, in the embodiments of the present invention, the meaning expressed by "and / or" can be both, or it can be either of the two.

[0065] In order to make the technical problems, technical solutions and advantages to be solved by the present invention more clear, a detailed description will be given below with reference to the accompanying drawings and specific embodiments.

[0066] The depleted shale gas reservoir of the embodiment of the present invention is located in the southern part of the Sichuan Basin, which is affected by the structural units such as the Shizhu syncline and the Wanxian syncline. The main gas-bearing layer is located in the Upper Ordovician Wufeng Formation and the Lower Silurian Longmaxi Formation. The reservoir is buried at a depth of 2500 to 4000 meters, the overall thickness of the gas reservoir is about 100 meters, and the thickness of the main gas-producing layer is 38 meters. The initial reservoir pressure ranges from 36 to 40 MPa, the average porosity is 4.87%, and the average permeability is 2.15×10 4 mD. Figure 1 The present invention provides a method for evaluating the maximum hydrogen storage potential of a depleted shale gas reservoir, which is implemented by a system for evaluating the maximum hydrogen storage potential of a depleted shale gas reservoir. The method includes:

[0067] S1. Based on the geological parameters and fluid physical parameters of depleted shale gas reservoirs, a physical model for evaluating the maximum hydrogen storage potential of multi-stage fractured horizontal wells in depleted shale gas reservoirs is established;

[0068] Specifically, the geological parameters and fluid physical property parameters of the depleted shale gas reservoir are shown in Table 1.

[0069] Table 1 - Geological parameters and fluid physical properties

[0070]

[0071] like Figure 5The schematic diagram of the physical model for evaluating the maximum hydrogen storage potential of a multi-stage fractured horizontal well in a depleted shale gas reservoir in the embodiment of the method for evaluating the maximum hydrogen storage potential of a depleted shale gas reservoir shown in the figure, the establishment conditions of the physical model for evaluating the maximum hydrogen storage potential of a multi-stage fractured horizontal well in a depleted shale gas reservoir include:

[0072] Condition 1: The depleted shale gas reservoir is a dual-medium reservoir. The fluid flow in the natural fractures is assumed to be a single-phase supercritical hydrogen flow, and the gas flow in the matrix is ​​a diffusion flow caused by concentration difference.

[0073] Condition 2: The seepage field formed during the hydrogen storage process of the depleted shale gas reservoir is simplified into two seepage zones, which include: a fractured reformed zone with higher permeability near the bottom of the well and an original formation zone with lower permeability;

[0074] Condition 3: The shale reservoir of the depleted shale gas reservoir is of uniform quality and thickness and has uniform depletion pressure;

[0075] Condition 4: The shale reservoir of the depleted shale gas reservoir has a closed circular boundary in the horizontal direction, and the top and bottom interfaces of the shale reservoir of the depleted shale gas reservoir are assumed to be impermeable boundaries;

[0076] Condition 5: Hydrogen flows in a one-dimensional linear manner in a complex hydraulic fracture network;

[0077] Condition 6: The hydrogen injection rate of the depleted shale gas reservoir during the hydrogen storage process is constant.

[0078] S2. Obtaining a mathematical model for evaluating the maximum hydrogen storage potential of multi-stage fractured horizontal wells in depleted shale gas reservoirs based on the physical model for evaluating the maximum hydrogen storage potential of multi-stage fractured horizontal wells in depleted shale gas reservoirs;

[0079] Specifically, Figure 2 The flowchart of the steps of establishing a mathematical model for evaluating the maximum hydrogen storage potential of a multi-stage fractured horizontal well in a depleted shale gas reservoir in an embodiment of the method for evaluating the maximum hydrogen storage potential of a depleted shale gas reservoir shown in the figure, wherein S2 obtains a mathematical model for evaluating the maximum hydrogen storage potential of a multi-stage fractured horizontal well in a depleted shale gas reservoir according to the physical model for evaluating the maximum hydrogen storage potential of a multi-stage fractured horizontal well in a depleted shale gas reservoir, including:

[0080] S21, obtaining the comprehensive diffusion rate, gas pseudo-pressure and dimensionless variable according to the physical model for evaluating the maximum hydrogen storage potential of multi-stage fractured horizontal wells in the depleted shale gas reservoir;

[0081] The calculation method of the comprehensive diffusion rate is:

[0082]

[0083] Where D e is the comprehensive diffusion coefficient, Dm is the molecular diffusion coefficient, D k is the Knudsen diffusion coefficient.

[0084] The calculation method of gas pseudo-pressure is:

[0085]

[0086] Where m is the bottom hole pressure during the hydrogen storage process of a multi-stage fractured horizontal well in a depleted shale gas reservoir, p is the pseudo-pressure solution of a multi-stage fractured horizontal well in a depleted shale gas reservoir in the real domain, μ is the viscosity of hydrogen, and Z is the compressibility factor of hydrogen.

[0087] Dimensionless variables include: dimensionless pseudo-pressure, dimensionless time, dimensionless distance, dimensionless wellbore storage coefficient, dimensionless stress sensitivity coefficient, dimensionless hydrogen injection rate, dimensionless hydraulic fracture conductivity, dimensionless comprehensive diffusion coefficient and dimensionless hydrogen concentration, where

[0088] The dimensionless pseudo-pressure is calculated as:

[0089]

[0090] In the formula, m j,D is the dimensionless pseudo-pressure of the depleted shale gas reservoir, m i is the initial pseudo pressure of the depleted shale gas reservoir, k ia,f is the permeability of the natural fracture system in the inner area of ​​the depleted shale gas reservoir; h is the reservoir thickness of the depleted shale gas reservoir, T is the reservoir temperature of the depleted shale gas reservoir, D represents dimensionless, T sc The temperature of the standard state, p sc The pressure at standard state, q sc The production under standard conditions, j=F represents the dimensionless seepage system of the hydraulic fracture system, j=f represents the dual-medium natural fracture zone system, j=m represents the seepage system of the dual-medium matrix zone, j=ia represents the inner area of ​​the reservoir after hydraulic fracturing transformation, and j=ea represents the external original formation area.

[0091] The dimensionless time is calculated as:

[0092]

[0093] Where, t D is dimensionless time, C g is the gas compressibility factor, t is the production time, and φ is the reservoir porosity.

[0094] The dimensionless distance is calculated as:

[0095]

[0096] In the formula, rD Dimensionless radial distance; x D Dimensionless distance in the direction of hydraulic fracture; h D Dimensionless reservoir thickness; z D Dimensionless vertical distance; L FD The dimensionless hydraulic fracture half-length; r is the radial distance; L is the reference length, x is the rectangular coordinate system distance; z is the rectangular coordinate system vertical distance; x F It is half the length of hydraulic fracture.

[0097] The calculation method of dimensionless wellbore storage coefficient is:

[0098]

[0099] Where, C is the wellbore storage coefficient, r is w Wellbore radius.

[0100] The calculation method of dimensionless stress sensitivity coefficient is:

[0101]

[0102] In the formula, α D is the dimensionless stress sensitivity coefficient, α is the stress sensitivity coefficient.

[0103] The dimensionless hydrogen injection rate is calculated as:

[0104]

[0105] In the formula, q j,D is the dimensionless hydrogen injection rate, q is the hydrogen injection rate.

[0106] The calculation method of dimensionless hydraulic fracture conductivity is:

[0107]

[0108] In the formula, C FD is the dimensionless hydraulic fracture conductivity, k F is the hydraulic fracture conductivity, w F Width of hydraulic fracture.

[0109] The calculation method of the dimensionless comprehensive diffusion coefficient is:

[0110]

[0111] Where D eD is the dimensionless comprehensive diffusion coefficient, D e is the effective diffusion coefficient, R m is the well diameter.

[0112] The dimensionless hydrogen concentration is calculated as:

[0113] V j,D =V i -V j (13)

[0114] Where V j,D Dimensionless hydrogen concentration, V j Hydrogen concentration, V i Hydrogen concentration at initial conditions.

[0115] The calculation method of adsorption index is:

[0116]

[0117] Where λ is the adsorption index, V L is the Langmuir isotherm adsorption volume; p L is the Langmuir isotherm adsorption pressure, μ i is the viscosity of hydrogen in the i-th crack, Z i is the compression factor of hydrogen in the i-th crack, p i is the pseudo-pressure solution of the i-th crack.

[0118] S22. According to the comprehensive diffusivity, gas pseudo-pressure and dimensionless variables, through perturbation transformation, a dimensionless mathematical model of hydraulic fracture system, a mathematical model of dual medium matrix area, a mathematical model of dual medium natural fracture area and a mathematical model of closed boundary reservoir are obtained;

[0119] The perturbation transformation methods include:

[0120]

[0121] In the formula, m j,D is the reservoir pseudo pressure, ζ j,D is the dimensionless pseudo-pressure after perturbation transformation, α D is the dimensionless stress sensitivity coefficient.

[0122] S23. Based on the dimensionless seepage mathematical model of hydraulic fracture system, the seepage mathematical model of dual-medium matrix zone, the seepage mathematical model of dual-medium natural fracture zone and the seepage mathematical model of closed boundary reservoir, the initial bars and internal and external boundary conditions are set to obtain the mathematical model for evaluating the maximum hydrogen storage potential of multi-stage fractured horizontal wells in depleted shale gas reservoirs.

[0123] Furthermore, the dimensionless seepage mathematical model of the hydraulic fracture system and its initial conditions and internal and external boundary conditions can be expressed as:

[0124]

[0125] In the formula, qF,wD is the dimensionless hydrogen injection rate at the bottom of the hydraulic fracture system.

[0126] The mathematical model of seepage in the dual medium matrix area and its initial conditions and internal and external boundary conditions can be expressed as follows:

[0127]

[0128] The mathematical model of seepage in the natural fracture zone of dual media and its initial conditions, composite interface conditions and internal and external boundary conditions can be expressed as follows:

[0129]

[0130] Where ω is the storage capacity ratio and M is the mobility ratio.

[0131] The mathematical model of seepage in closed boundary reservoirs and its initial conditions, top and bottom interface conditions, and internal and external boundary conditions can be expressed as follows:

[0132]

[0133] in,

[0134] In the formula, m i is the pseudo pressure in the initial state.

[0135] S3. Based on the mathematical model for evaluating the maximum hydrogen storage potential of multi-stage fractured horizontal wells in the depleted shale gas reservoir, the bottom hole pseudo-pressure solution in the Latten space is obtained based on the Latten transformation technology and Bessel function theory;

[0136] Specifically, Figure 3 The flowchart of the steps of obtaining the bottom hole pseudo-pressure solution under the pull-type space in the embodiment of the method for evaluating the maximum hydrogen storage potential of a depleted shale gas reservoir shown in the figure, S3 obtains the bottom hole pseudo-pressure solution under the pull-type space according to the mathematical model for evaluating the maximum hydrogen storage potential of a multi-stage fractured horizontal well in a depleted shale gas reservoir based on the pull-type transformation technology and Bessel function theory, including:

[0137] S31. According to the dimensionless mathematical model of seepage in the hydraulic fracture system, the dimensionless pseudo-pressure solution of the dimensionless mathematical model of seepage in the hydraulic fracture system is obtained by using the pull-type transformation technology.

[0138]

[0139] In the formula, is the dimensionless pseudo-pressure solution of the i-th fracture segment in the dimensionless seepage mathematical model of the hydraulic fracture system, is the dimensionless pseudo-pressure solution at the bottom of the well in the dimensionless seepage mathematical model of the hydraulic fracture system. is the length of the i-th crack segment, is the position of the i-th crack segment, is the dimensionless hydrogen injection rate at the position of the i-th fracture segment in the dimensionless seepage mathematical model of the hydraulic fracture system under tension conditions.

[0140]

[0141] When hydrogen is injected at a constant rate, the sum of the flow rates of all fracture segments is 1, as shown in formula (22):

[0142]

[0143] Where N f is the number of hydraulic fracturing cracks, N w is the number of fracture segments of each hydraulic fracture.

[0144] S32. According to the mathematical model of seepage in the dual medium matrix area, the dimensionless solution of the mathematical model of seepage in the dual medium matrix area is obtained by using the Latent transformation technology.

[0145]

[0146] In the formula, is the dimensionless hydrogen concentration in the reservoir after hydraulic fracturing under pull conditions, is the dimensionless pseudo-pressure after perturbation transformation in the reservoir after hydraulic fracturing under tensile conditions, is the dimensionless hydrogen concentration in the original formation region outside the pull condition, is the dimensionless pseudo-pressure after perturbation transformation of the external original formation area under tension condition.

[0147] S33, according to the mathematical model of seepage in the natural fracture zone of dual medium, by using the Latent transformation technology, a dimensionless solution of the mathematical model of seepage in the natural fracture zone of dual medium is obtained;

[0148]

[0149] In the formula, is the dimensionless pseudo-pressure after perturbation transformation of the natural fracture system under tension conditions after hydraulic fracturing. is the dimensionless pseudo-pressure after perturbation transformation of the external original formation area under the tensile condition, is the dimensionless hydrogen injection rate under the pull condition, σ is the dispersion ratio, I0 is the first Bessel function of the first kind, I1 is the second Bessel function of the first kind, K0 is the first Bessel function of the second kind, and K1 is the second Bessel function of the second kind.

[0150] S34, according to the mathematical model of seepage in the closed boundary reservoir, by using the Lassen transformation technique and Bessel function theory, a dimensionless pseudo-pressure solution of the mathematical model of seepage in the closed boundary reservoir is obtained;

[0151]

[0152] in,

[0153] S35. Based on the dimensionless pseudo-pressure solution of the dimensionless seepage mathematical model of the hydraulic fracture system, the dimensionless solution of the seepage mathematical model of the dual medium matrix zone, the dimensionless solution of the seepage mathematical model of the dual medium natural fracture zone and the dimensionless pseudo-pressure solution of the seepage mathematical model of the closed boundary reservoir, the surface effect and the wellbore reservoir effect are considered to obtain the bottom hole pseudo-pressure solution in the pull space.

[0154] Furthermore, based on the point source function and numerical integration method, the flow rate of the lth fracture segment on the kth fracture and the pressure response of the jth fracture segment on the ith fracture are obtained.

[0155]

[0156] in, ΔL FD =2L FD / N w .

[0157] Based on the principle of pressure superposition, the pressure response of the jth fracture segment in the i-th fracture is obtained.

[0158]

[0159] In the formula, represents the dimensionless flow of the lth fracture segment on the kth fracture.

[0160] Considering the interaction between each hydraulic fracture in a multi-stage fracturing horizontal well, the pressure response of all fracture segments in the kth fracture caused by the hydrogen flow in the nth fracture is obtained:

[0161]

[0162] N f The pressure response of the coupled fractures can be summarized as f ×N w The corresponding coefficient matrix can be expressed as:

[0163]

[0164] Finally, the pressure superposition principle was used to obtain the matrix equation of the mathematical model for evaluating the maximum hydrogen storage potential of multi-stage fractured horizontal wells in depleted shale gas reservoirs under the conditions of complex fracture networks, multiple hydrogen transmission mechanisms and well interference.

[0165]

[0166] In the formula, E is the pressure superposition coefficient matrix of the analytical solution of natural fractures; F is the coefficient matrix of the numerical solution of the hydraulic fracture network.

[0167] The bottom hole pseudo pressure solution in the pull domain considering the skin effect and wellbore reservoir effect is:

[0168]

[0169] Where S is the skin coefficient.

[0170] S4. Based on the bottom hole pseudo-pressure solution in the pull-type space, the Stehfest numerical inversion method is used to obtain the pseudo-pressure solution of the multi-stage fractured horizontal well in the depleted shale gas reservoir in the real domain;

[0171] Specifically, Figure 4 The flowchart of the steps of obtaining the pseudo-pressure solution of the multi-stage fractured horizontal well in the depleted shale gas reservoir in the real domain in the embodiment of the method for evaluating the maximum hydrogen storage potential of the depleted shale gas reservoir shown in the figure, wherein S4 uses the Stehfest numerical inversion method according to the bottom hole pseudo-pressure solution in the pull-type space to obtain the pseudo-pressure solution of the multi-stage fractured horizontal well in the depleted shale gas reservoir in the real domain, including:

[0172] S41, according to the bottom hole pseudo-pressure solution in the Laplace space, through the Laplace inverse transformation, obtain the bottom hole pseudo-pressure solution after inverse transformation;

[0173]

[0174] In the formula, ζ D (t D ) is the bottom hole pseudo-pressure solution after inverse transformation, and N is an empirical constant, which is generally taken as 8, 10, or 12.

[0175] S42, according to the bottom hole pseudo-pressure solution after the inverse transformation, the dimensionless bottom hole pseudo-pressure solution is obtained by approximating the dimensionless zero-order perturbation solution;

[0176]

[0177] Where p is the pseudo-pressure solution of multi-stage fractured horizontal wells in depleted shale gas reservoirs in the real domain.

[0178] S43. Based on the dimensionless pseudo-pressure solution of the bottom hole, the pseudo-pressure solution of the multi-stage fractured horizontal well in the depleted shale gas reservoir in the real domain is obtained.

[0179] By giving a value of i and a value of t, calculate V i The value of V is calculated at each time step. i The pseudo-pressure solution of multi-stage fractured horizontal wells in depleted shale gas reservoirs in the real domain is obtained.

[0180] S5. According to the pseudo-pressure solution of the multi-stage fractured horizontal well in the depleted shale gas reservoir in the real domain, the bottom hole pressure change of the multi-stage fractured horizontal well in the depleted shale gas reservoir during the hydrogen storage process is obtained by using the pseudo-pressure calculation method;

[0181] Specifically, the pseudo-pressure calculation method includes:

[0182]

[0183] Where m is the bottom hole pressure during hydrogen storage in a multi-stage fractured horizontal well in a depleted shale gas reservoir, p is the pseudo-pressure solution of a multi-stage fractured horizontal well in a depleted shale gas reservoir in the real domain, and μ i is the viscosity of hydrogen at the ith pressure point, μ i-1 is the viscosity of hydrogen at the i-1th pressure point, Z i is the compressibility factor of hydrogen at the ith pressure point, Z i-1 is the compression factor of hydrogen at the i-1th pressure point, p i is the pressure value of the ith pressure point, p i-1 is the pressure value of the i-1th pressure point, and n is the total number of pressure points.

[0184] According to formula (3), Figure 6 The graph showing the relationship between pseudo pressure and pressure in an embodiment of a method for assessing the maximum hydrogen storage potential of a depleted shale gas reservoir is shown.

[0185] S6. According to the bottom hole pressure change during the hydrogen storage process of the multi-stage fractured horizontal well of the depleted shale gas reservoir, the maximum storage potential of hydrogen under different constraint pressures is obtained by the hydrogen injection time under different constraint pressures.

[0186] Specifically, Figure 7 The relationship curve diagram of the injection time and the constraint pressure in the embodiment of the method for evaluating the maximum hydrogen storage potential of a depleted shale gas reservoir shown in the figure; the hydrogen injection time under different constraint pressures is obtained, and the maximum hydrogen storage potential under different constraint pressures is obtained by formula (43), and the following is obtained: Figure 8 The relationship curve between the confinement pressure and the hydrogen storage volume in the embodiment of the method for evaluating the maximum hydrogen storage potential of a depleted shale gas reservoir shown in FIG.

[0187] M t =Q sc ×t con (43)

[0188] Where Mt Represents the storage capacity of hydrogen, Q sc is the injection rate during hydrogen storage, t con The time it takes for the hydrogen storage process in a shale reservoir to be completed.

[0189] like Fig. 9 The system block diagram of the embodiment of the maximum hydrogen storage potential evaluation system for depleted shale gas reservoirs shown in the figure, the present invention provides a maximum hydrogen storage potential evaluation system for depleted shale gas reservoirs, the system is applied to a maximum hydrogen storage potential evaluation method for depleted shale gas reservoirs, the system comprises: a physical model establishment module, a mathematical model establishment module, a first calculation module, a second calculation module, a third calculation module, and a fourth calculation module, specifically,

[0190] A physical model building module is used to build a physical model for evaluating the maximum hydrogen storage potential of multi-stage fractured horizontal wells in depleted shale gas reservoirs based on the geological parameters and fluid physical property parameters of the depleted shale gas reservoirs;

[0191] A mathematical model building module is used to obtain a mathematical model for evaluating the maximum hydrogen storage potential of multi-stage fractured horizontal wells in depleted shale gas reservoirs based on the physical model for evaluating the maximum hydrogen storage potential of multi-stage fractured horizontal wells in depleted shale gas reservoirs;

[0192] The first calculation module is used to obtain the bottom hole pseudo-pressure solution in the Lattices space based on the mathematical model for evaluating the maximum hydrogen storage potential of the multi-stage fractured horizontal well in the depleted shale gas reservoir, based on the Lattices transformation technology and Bessel function theory;

[0193] The second calculation module is used to obtain the pseudo-pressure solution of the multi-stage fractured horizontal well in the depleted shale gas reservoir in the real domain by using the Stehfest numerical inversion method according to the bottom hole pseudo-pressure solution in the pull-type space;

[0194] The third model module is used to obtain the bottom hole pressure change of the multi-stage fractured horizontal well in the depleted shale gas reservoir during the hydrogen storage process by using the pseudo-pressure calculation method according to the pseudo-pressure solution of the multi-stage fractured horizontal well in the depleted shale gas reservoir in the real domain;

[0195] The fourth calculation module is used to obtain the maximum storage potential of hydrogen under different constraint pressures according to the change of bottom hole pressure during the hydrogen storage process of the multi-stage fracturing horizontal well of the depleted shale gas reservoir and the hydrogen injection time under different constraint pressures.

[0196] The present invention provides a method and system for evaluating the maximum hydrogen storage potential of a depleted shale gas reservoir. The present invention establishes a physical model and a mathematical model for evaluating the maximum hydrogen storage potential of a multi-stage fractured horizontal well in a depleted shale gas reservoir, comprehensively considers the actual situation of the multi-stage fractured horizontal well and various influencing factors, and makes the result more reliable. At the same time, based on the Latten transformation technology and the Bessel function theory, the maximum storage potential of hydrogen under different constraint pressures is obtained through a pseudo-pressure calculation method, the calculation process is simplified, and a rapid and accurate evaluation of the hydrogen storage potential in a depleted shale gas reservoir is achieved, making the evaluation more efficient and accurate.

[0197] It is to be understood that the present invention is described by the above embodiments and should not be construed as limiting the embodiments of the present invention and the scope of the present invention. It is known to those skilled in the art that various changes or equivalent substitutions may be made to these features and embodiments without departing from the spirit and scope of the present invention. In addition, under the teachings of the present invention, these features and embodiments may be modified to adapt to specific circumstances and materials without departing from the spirit and scope of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are within the scope of protection of the present invention.

Claims

1. A method for evaluating the maximum hydrogen storage potential of a depleted shale gas reservoir, characterized in that: The method comprises: S1. Based on the geological parameters and fluid physical parameters of depleted shale gas reservoirs, a physical model for evaluating the maximum hydrogen storage potential of multi-stage fractured horizontal wells in depleted shale gas reservoirs is established; S2. Obtaining a mathematical model for evaluating the maximum hydrogen storage potential of multi-stage fractured horizontal wells in depleted shale gas reservoirs according to the physical model for evaluating the maximum hydrogen storage potential of multi-stage fractured horizontal wells in depleted shale gas reservoirs; S3, according to the mathematical model for evaluating the maximum hydrogen storage potential of multi-stage fractured horizontal wells in depleted shale gas reservoirs, based on the Lassen transformation technology and Bessel function theory, the bottom hole pseudo-pressure solution in the Lassen space is obtained; S4, according to the bottom hole pseudo-pressure solution in the pull-type space, using the Stehfest numerical inversion method, obtain the pseudo-pressure solution of the multi-stage fractured horizontal well in the depleted shale gas reservoir in the real domain; S5. According to the pseudo-pressure solution of the multi-stage fractured horizontal well in the depleted shale gas reservoir in the real domain, using the pseudo-pressure calculation method, obtain the bottom hole pressure change of the multi-stage fractured horizontal well in the depleted shale gas reservoir during the hydrogen storage process; S6. According to the change of bottom hole pressure during the hydrogen storage process of the multi-stage fractured horizontal well in the depleted shale gas reservoir, the maximum storage potential of hydrogen under different constraint pressures is obtained by hydrogen injection time under different constraint pressures.

2. The method for evaluating the maximum hydrogen storage potential of a depleted shale gas reservoir according to claim 1, characterized in that: The conditions for establishing the physical model for evaluating the maximum hydrogen storage potential of multi-stage fractured horizontal wells in depleted shale gas reservoirs include: Condition 1: The depleted shale gas reservoir is a dual-medium reservoir. The fluid flow in the natural fractures is assumed to be a single-phase supercritical hydrogen flow, and the gas flow in the matrix is ​​a diffusion flow caused by concentration difference. Condition 2: The seepage field formed during the hydrogen storage process of the depleted shale gas reservoir is simplified into two seepage zones, which include: a fractured reformed zone with higher permeability near the bottom of the well and an original formation zone with lower permeability; Condition 3: The shale reservoir of the depleted shale gas reservoir is of uniform quality and thickness and has uniform depletion pressure; Condition 4: The shale reservoir of the depleted shale gas reservoir has a closed circular boundary in the horizontal direction, and the top and bottom interfaces of the shale reservoir of the depleted shale gas reservoir are assumed to be impermeable boundaries; Condition 5: Hydrogen flows in a one-dimensional linear manner in a complex hydraulic fracture network; Condition 6: The hydrogen injection rate of the depleted shale gas reservoir during the hydrogen storage process is constant.

3. The method for evaluating the maximum hydrogen storage potential of a depleted shale gas reservoir according to claim 1, characterized in that: The mathematical model for evaluating the maximum hydrogen storage potential of multi-stage fractured horizontal wells in depleted shale gas reservoirs is obtained in S2 according to the physical model for evaluating the maximum hydrogen storage potential of multi-stage fractured horizontal wells in depleted shale gas reservoirs, including: S21, obtaining a comprehensive diffusion rate, a gas pseudo-pressure and a dimensionless variable according to the physical model for evaluating the maximum hydrogen storage potential of multi-stage fractured horizontal wells in depleted shale gas reservoirs; S22, according to the comprehensive diffusivity, the gas pseudo-pressure and the dimensionless variable, through perturbation transformation, obtain a dimensionless seepage mathematical model of the hydraulic fracture system, a seepage mathematical model of the dual medium matrix area, a seepage mathematical model of the dual medium natural fracture area and a seepage mathematical model of the closed boundary reservoir; S23. According to the dimensionless seepage mathematical model of the hydraulic fracture system, the seepage mathematical model of the dual-medium matrix zone, the seepage mathematical model of the dual-medium natural fracture zone and the seepage mathematical model of the closed boundary reservoir, initial bars and internal and external boundary conditions are set to obtain a mathematical model for evaluating the maximum hydrogen storage potential of multi-stage fractured horizontal wells in depleted shale gas reservoirs.

4. The method for evaluating the maximum hydrogen storage potential of a depleted shale gas reservoir according to claim 3, characterized in that: The method for calculating the comprehensive diffusion rate includes: Where D e is the comprehensive diffusion coefficient, D m is the molecular diffusion coefficient, D k is the Knudsen diffusion coefficient.

5. The method for evaluating the maximum hydrogen storage potential of a depleted shale gas reservoir according to claim 3, characterized in that: The dimensionless variables include: dimensionless pseudo-pressure, dimensionless time, dimensionless distance, dimensionless wellbore storage coefficient, dimensionless stress sensitivity coefficient, dimensionless hydrogen injection rate, dimensionless hydraulic fracture conductivity, dimensionless comprehensive diffusion coefficient and dimensionless hydrogen concentration.

6. The method for evaluating the maximum hydrogen storage potential of a depleted shale gas reservoir according to claim 3, characterized in that: The perturbation transformation method comprises: In the formula, m j,D is the reservoir pseudo pressure, ζ j,D is the dimensionless pseudo-pressure after perturbation transformation, α D is the dimensionless stress sensitivity coefficient.

7. The method for evaluating the maximum hydrogen storage potential of a depleted shale gas reservoir according to claim 3, characterized in that: In S3, according to the mathematical model for evaluating the maximum hydrogen storage potential of the multi-stage fractured horizontal well in the depleted shale gas reservoir, based on the Latsch transform technology and Bessel function theory, the bottom hole pseudo-pressure solution in the Latsch space is obtained, including: S31, according to the dimensionless seepage mathematical model of the hydraulic fracture system, by using the pull-type transformation technology, obtaining the dimensionless pseudo-pressure solution of the dimensionless seepage mathematical model of the hydraulic fracture system; S32, according to the seepage mathematical model of the dual medium matrix area, by using the Latent transformation technology, obtaining a dimensionless solution of the seepage mathematical model of the dual medium matrix area; S33, according to the mathematical model of seepage in the dual medium natural fracture zone, by using the Latent transformation technology, obtaining a dimensionless solution of the mathematical model of seepage in the dual medium natural fracture zone; S34, according to the seepage mathematical model of the closed boundary reservoir, by using the Lassen transformation technology and Bessel function theory, obtaining a dimensionless pseudo-pressure solution of the seepage mathematical model of the closed boundary reservoir; S35. According to the dimensionless pseudo-pressure solution of the dimensionless seepage mathematical model of the hydraulic fracture system, the dimensionless solution of the seepage mathematical model of the dual-medium matrix zone, the dimensionless solution of the seepage mathematical model of the dual-medium natural fracture zone and the dimensionless pseudo-pressure solution of the seepage mathematical model of the closed boundary reservoir, the skin effect and the wellbore storage effect are taken into consideration to obtain the bottom hole pseudo-pressure solution in the pull-type space.

8. The method for evaluating the maximum hydrogen storage potential of a depleted shale gas reservoir according to claim 1, characterized in that: In S4, according to the bottom hole pseudo-pressure solution in the pull-type space, the Stehfest numerical inversion method is used to obtain the pseudo-pressure solution of the multi-stage fractured horizontal well in the depleted shale gas reservoir in the real domain, including: S41, according to the bottom hole pseudo-pressure solution in the Laplace space, obtain the bottom hole pseudo-pressure solution after inverse transformation by Laplace inverse transformation; S42, according to the inverse-transformed bottom hole pseudo-pressure solution, approximate the bottom hole dimensionless pseudo-pressure solution by using a dimensionless zero-order perturbation solution; S43. According to the dimensionless pseudo-pressure solution of the bottom hole, a pseudo-pressure solution of a multi-stage fractured horizontal well in a depleted shale gas reservoir in a real domain is obtained.

9. The method for evaluating the maximum hydrogen storage potential of a depleted shale gas reservoir according to claim 1, characterized in that: The pseudo-pressure calculation method comprises: Where m is the bottom hole pressure during hydrogen storage in a multi-stage fractured horizontal well in a depleted shale gas reservoir, p is the pseudo-pressure solution of a multi-stage fractured horizontal well in a depleted shale gas reservoir in the real domain, and μ i is the viscosity of hydrogen at the ith pressure point, μ i-1 is the viscosity of hydrogen at the i-1th pressure point, Z i is the compressibility factor of hydrogen at the ith pressure point, Z i-1 is the compression factor of hydrogen at the i-1th pressure point, p i is the pressure value of the ith pressure point, p i-1 is the pressure value of the i-1th pressure point, and n is the total number of pressure points.

10. A system for evaluating the maximum hydrogen storage potential of depleted shale gas reservoirs, characterized in that: The system comprises: A physical model building module is used to build a physical model for evaluating the maximum hydrogen storage potential of multi-stage fractured horizontal wells in depleted shale gas reservoirs based on the geological parameters and fluid physical property parameters of the depleted shale gas reservoirs; A mathematical model building module, used to obtain a mathematical model for evaluating the maximum hydrogen storage potential of multi-stage fractured horizontal wells in depleted shale gas reservoirs based on the physical model for evaluating the maximum hydrogen storage potential of multi-stage fractured horizontal wells in depleted shale gas reservoirs; The first calculation module is used to obtain the bottom hole pseudo-pressure solution in the Lattices space based on the mathematical model for evaluating the maximum hydrogen storage potential of the multi-stage fractured horizontal well in the depleted shale gas reservoir, based on the Lattices transformation technology and Bessel function theory; The second calculation module is used to obtain the pseudo-pressure solution of the multi-stage fractured horizontal well in the depleted shale gas reservoir in the real domain by using the Stehfest numerical inversion method according to the bottom hole pseudo-pressure solution in the pull-type space; The third model module is used to obtain the bottom hole pressure change of the multi-stage fractured horizontal well in the depleted shale gas reservoir during the hydrogen storage process by using the pseudo-pressure calculation method according to the pseudo-pressure solution of the multi-stage fractured horizontal well in the depleted shale gas reservoir in the real domain; The fourth calculation module is used to obtain the maximum storage potential of hydrogen under different constraint pressures according to the change of bottom hole pressure during the hydrogen storage process of the multi-stage fractured horizontal well in the depleted shale gas reservoir and the hydrogen injection time under different constraint pressures.

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