High-sulfur-content gas reservoir sulfur deposition prediction method, readable storage medium and device

Abstract

The invention discloses a high-sulfur-content gas reservoir sulfur deposition prediction method, a readable storage medium and a high-sulfur-content gas reservoir sulfur deposition prediction device, and belongs to the technical field of high-sulfur-content gas reservoir development. The method comprises the following steps: establishing a first equation of sulfur saturation based on volume change caused by sulfur deposition in unit time; introducing a high-speed non-Darcy seepage effect to form an equation II; determining the gas-phase relative permeability considering the active degree of the water body through a substance balance principle, substituting the gas-phase relative permeability into the equation II, and constructing an equation III considering the non-darcy effect and the water body influence at the same time; and carrying out numerical integration to obtain a sulfur saturation prediction model. A computer program for performing the prediction method is stored in the readable storage medium. The prediction device comprises a memory, a processor and a terminal program capable of performing corresponding steps of the prediction method. The method comprehensively considers the influence of the high-speed non-Darcy effect and the active degree of the water body, achieves the precise prediction of the sulfur deposition of the high-sulfur-content gas reservoir, and is suitable for the prediction and evaluation of the sulfur deposition in the development process of the high-sulfur-content gas reservoir.

Description

Technical Field

[0001] This application belongs to the field of high-sulfur gas reservoir development technology, and particularly relates to a method for predicting sulfur deposition in high-sulfur gas reservoirs, a readable storage medium, and a device. Background Technology

[0002] my country has a wide distribution of high-sulfur gas reservoirs with promising development prospects. However, during development, as formation pressure decreases, sulfur gradually precipitates and deposits, leading to blockage of seepage channels and severely restricting the development efficiency of gas reservoirs. Therefore, accurately predicting sulfur deposition phenomena is of great significance for optimizing gas well production systems, developing efficient unblocking measures, and improving the overall development effect of gas reservoirs.

[0003] Currently, existing sulfur deposition prediction models mostly focus on factors such as seepage and stress, and generally fail to incorporate the activity level of formation water into the analysis of influencing mechanisms. However, in actual development, as gas reservoir production progresses, edge and bottom water gradually intrudes into the reservoir, and the activity level of the water will have a significant impact on the production dynamics and sulfur deposition process of high-sulfur gas reservoirs.

[0004] Therefore, it is necessary to establish a sulfur deposition prediction method that integrates the high-speed non-Darcy effect and the water activity level. This method has important theoretical and practical significance for the accurate prediction of sulfur deposition in high-sulfur gas reservoirs and the formulation of reasonable unblocking strategies. Summary of the Invention

[0005] This application aims to address the technical problem that existing methods for predicting sulfur deposition in gas reservoirs do not consider the influence of water activity. To this end, this application provides a method, readable storage medium, and device for predicting sulfur deposition in high-sulfur gas reservoirs. It comprehensively considers the influence of high-velocity non-Darcy effect and water activity, achieving accurate prediction of sulfur deposition in high-sulfur gas reservoirs. It is applicable to sulfur deposition prediction and assessment during the development of high-sulfur gas reservoirs.

[0006] In a first aspect, embodiments of this application provide a method for predicting sulfur deposition in high-sulfur gas reservoirs, comprising: Based on the volume change of sulfur element caused by sulfur deposition per unit time, a sulfur saturation equation for sulfur in porous media in gas reservoirs is established. Based on high-speed non-Darcy seepage, a second sulfur saturation equation considering the high-speed non-Darcy effect is established. Based on the principle of material balance, the relative permeability of the gas phase, taking into account the activity level of the water body, is determined by combining the water production and relative permeability in the gas reservoir. Substituting the relative permeability of the gas phase into sulfur saturation equation two, we establish sulfur saturation equation three, which considers the high-speed non-Darcy effect and the activity level of the water body.

[0007] Numerical integration of sulfur saturation equation three yields a predictive model for sulfur saturation. The deposition of sulfur in the gas reservoir was obtained by calculation using a predictive model.

[0008] In some implementations, the third sulfur saturation equation, considering the high-speed non-Darcy effect and the water activity level, is: ; in, Sulfur saturation; Production time, in days; Here is the viscosity of natural gas, in mPa·s; For reservoir permeability, 10 -3 μm 2 ; The relative permeability of the gas phase, taking into account the activity level of the water body; For the surface gas production of the gas well, ; This is the volume factor for natural gas; For the solubility of sulfur, ; Formation pressure, MPa; Let be the radial distance, in meters, from any point in the formation to the wellbore. The effective thickness of the gas reservoir is in meters (m). Initial porosity; It is a natural constant; These are the fitting coefficients; Density of solid sulfur ; For natural gas density ; To bind water saturation; For non-Darcy flow coefficients, .

[0009] In some implementations, the prediction model is: ; in, ; .

[0010] In some implementations, the relative permeability of the gas phase, taking into account the activity level of the water body, is: ; in, This refers to the relative permeability of the gas phase. This represents the relative gas-phase permeability corresponding to the bound water saturation. This represents the relative permeability of the aqueous phase corresponding to the residual gas saturation. These are intermediate parameters used in the calculation process; Corey index for aqueous phase; This refers to the Corey index in the gas phase.

[0011] In some implementations, the second sulfur saturation equation considering the high-speed non-Darcy effect is: ; in, Sulfur saturation; Production time, in days; Here is the viscosity of natural gas, in mPa·s; For reservoir permeability, 10 -3 μm 2 ; The relative permeability of the gas phase, taking into account the activity level of the water body; For the surface gas production of the gas well, ; This is the volume factor for natural gas; For the solubility of sulfur, ; Formation pressure, MPa; Let be the radial distance, in meters, from any point in the formation to the wellbore. The effective thickness of the gas reservoir is in meters (m). Porosity of the gas reservoir; Density of solid sulfur ; For natural gas density ; To bind water saturation; For non-Darcy flow coefficients, .

[0012] In some implementations, the gas phase in the gas reservoir satisfies the high-velocity non-Darcy flow law, while the liquid phase satisfies the Darcy flow law.

[0013] In some implementations, the predicted areas of sulfur deposition in the gas reservoir are kept under constant temperature conditions during development.

[0014] In some implementations, the gas reservoir is horizontal, homogeneous, and of uniform thickness, and the sulfur precipitates and settles in the reservoir.

[0015] Secondly, embodiments of this application provide a readable storage medium storing a computer program, which, when executed, performs the sulfur deposition prediction method for high-sulfur gas reservoirs as described above.

[0016] Thirdly, embodiments of this application provide a sulfur deposition prediction device for high-sulfur gas reservoirs, including a memory, a processor, and a terminal program stored in the memory and capable of running in the processor. The terminal program includes execution steps corresponding to the sulfur deposition prediction method for high-sulfur gas reservoirs described above.

[0017] As can be seen from the above technical solution, the beneficial effects of this application are as follows: 1. The prediction method of this application establishes a sulfur saturation equation one based on the volume change of sulfur element per unit time, introducing sulfur deposition kinetics; and establishes equation two by combining the high-speed non-Darcy effect. Since the non-Darcy term introduces velocity-dependent seepage resistance, it avoids the deviation of Darcy's law under high-speed conditions, thus capturing the deposition location and rate of sulfur particles. The relationship between water production and relative permeability is quantified through the principle of mass balance, determining the gas phase relative permeability considering the water body activity level, resulting in equation three, which quantifies the impact of different water body activity levels, different production regimes, and different production times on the sulfur deposition process. Finally, numerical integration of equation three yields a multi-physics coupled dynamic prediction model, realizing rapid and continuous quantitative calculation and dynamic prediction of sulfur saturation based on field production data, capable of real-time response to changes in production regime and time. This application comprehensively considers the influence of the high-speed non-Darcy effect and the water body activity level, achieving accurate prediction of sulfur deposition in high-sulfur gas reservoirs, and is applicable to sulfur deposition prediction and assessment during the development of high-sulfur gas reservoirs. Meanwhile, developers can optimize and adjust production systems in advance based on predicted sulfur deposition risks, and accurately formulate and implement sulfur removal and unblocking measures to effectively mitigate reservoir damage, maintain normal gas well production, and ultimately achieve safe and efficient development of high-sulfur gas reservoirs.

[0018] 2. The readable storage medium of this application solidifies the sulfur deposition prediction method for high-sulfur gas reservoirs into a computer program within the readable storage medium. By using the readable storage medium as a carrier, the prediction method can be programmed and encapsulated, transforming the complex calculation prediction model into instruction code that can be automatically and accurately executed by a computer. This ensures real-time and rapid prediction of high-sulfur gas reservoirs, directly realizing the efficient, stable, and reusable engineering application and promotion of the prediction method, and providing efficient and reliable tool support for development decisions.

[0019] 3. The prediction device of this application has a memory that solidifies the complex prediction model and calculation steps into a set of instructions that can be stably called, while the processor provides dedicated computing resources to ensure that these instructions are executed continuously at high speed and accuracy. By mounting the hardware entity of the device, it constitutes a decision-making device, which provides a guarantee for the development of high-sulfur gas reservoirs and realizes the effective application and ease of application of the prediction method. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced one by one below. Obviously, the accompanying drawings described below are some embodiments of this application. For those skilled in the art, other embodiments and drawings can be obtained based on these drawings without creative effort. The block diagrams shown in the drawings are merely functional entities and do not necessarily correspond to physically independent entities. That is, these functional entities can be implemented in software, or in one or more hardware modules or integrated circuits, or in different network and / or processor devices and / or microcontroller devices. The flowcharts shown in the drawings are merely illustrative and do not necessarily include all contents and operations / steps, nor do they necessarily have to be performed in the described order. For example, some operations / steps can be decomposed, while some operations / steps can be combined or partially combined. Therefore, the actual execution order may change according to the actual situation.

[0021] Figure 1 A schematic diagram illustrating the steps of an embodiment of the method for predicting sulfur deposition in high-sulfur gas reservoirs according to the present invention is shown; Figure 2 The diagram illustrates sulfur deposition at different production times, representing an example of the application of this invention. Detailed Implementation

[0022] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. The detailed description of the embodiments of this application provided in the drawings is not intended to limit the scope of the claimed application. The described embodiments are only a part of the embodiments of this application, not all of them. Based on the embodiments in this application, they can be arranged and designed in various different configurations. All other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0023] This application is described below with reference to the accompanying drawings and specific embodiments: Please refer to Figure 1 The first aspect of this application provides a method for predicting sulfur deposition in high-sulfur gas reservoirs, comprising: S1. As sulfur precipitates and deposits, occupying the pore space of the porous medium in the gas reservoir, a sulfur saturation equation (Equation 1) is established based on the volume change of sulfur caused by sulfur deposition per unit time. This equation quantifies the increase in sulfur volume per unit time and unit volume of rock due to sulfur precipitation and deposition from the gas phase, and is related to factors such as gas flow rate and sulfur saturation. By establishing Equation 1, the fundamental kinetic process of sulfur saturation changing over time can be described.

[0024] S2. Combining high-speed non-Darcy flow, establish a second sulfur saturation equation considering the high-speed non-Darcy effect. Under high-speed flow conditions, inertial forces become significant, and the fluid flow pattern no longer conforms to the linear relationship of Darcy's law, exhibiting non-Darcy flow characteristics. This step, by introducing a term describing the high-speed non-Darcy effect into the first saturation equation, allows for a more accurate calculation of the gas flow's ability to transport sulfur particles, enabling the model to more realistically reflect the sulfur deposition behavior in the near-wellbore zone.

[0025] S3. Combining the water production and relative permeability in the gas reservoir, and based on the principle of mass balance, the relative permeability of the gas phase, taking into account the activity level of the water body, is determined. This step quantifies the impact of formation water activity on sulfur deposition. When water is produced in the gas reservoir or when edge and bottom water intrudes, the water saturation in the porous medium changes. According to the multiphase flow theory, an increase in water saturation significantly reduces the relative permeability of the gas phase, thereby hindering gas flow and altering its flow path. Based on the principle of mass balance, the change in water saturation in the formation is inferred or predicted using water production data, thereby determining the relative permeability value of the gas phase under the corresponding conditions, considering the coexistence of gas and water phases.

[0026] S4. Substitute the relative permeability of the gas phase into sulfur saturation equation two to establish sulfur saturation equation three, which considers the high-velocity non-Darcy effect and the activity level of the formation water. Substitute the relative permeability parameter of the gas phase, which already includes the influence of water activity, into sulfur saturation equation two, and finally form a unified sulfur saturation equation three that can comprehensively reflect the two key physical processes of high-velocity non-Darcy seepage effect and formation water activity level, thereby obtaining a prediction model.

[0027] S5. Numerically integrate the third sulfur saturation equation to obtain a prediction model for sulfur saturation. Solving the third sulfur saturation equation using numerical integration essentially discretizes the continuous physical process in time and space, transforming it into a dynamic prediction model that can be used for practical calculations.

[0028] S6. Calculate sulfur deposition in the gas reservoir using a predictive model. Initial geological parameters of the gas reservoir (such as porosity and permeability), fluid properties (such as natural gas viscosity and gas volume coefficient), and actual production data (such as gas production, water production, and production time) are used as input conditions and substituted into the established numerical prediction model for calculation. This allows for the rapid acquisition of sulfur saturation distribution at different locations and production times throughout the entire gas reservoir or target well area. The prediction results accurately characterize the variation patterns of sulfur deposition, providing crucial scientific data support for development decisions.

[0029] In some implementations, in step S4 above, the sulfur saturation equation three, considering the high-speed non-Darcy effect and the water activity level, is: in, Sulfur saturation; Production time, in days; Here is the viscosity of natural gas, in mPa·s; For reservoir permeability, 10 -3 μm 2 ; The relative permeability of the gas phase, taking into account the activity level of the water body; For the surface gas production of the gas well, ; This is the volume factor for natural gas; For the solubility of sulfur, ; Formation pressure, MPa; Let be the radial distance, in meters, from any point in the formation to the wellbore. The effective thickness of the gas reservoir is in meters (m). Initial porosity; It is a natural constant; These are the fitting coefficients; Density of solid sulfur ; For natural gas density ; To bind water saturation; For non-Darcy flow coefficients, .

[0030] In some implementations, the prediction model in step S5 above is: in, ; ; S s Sulfur saturation; t Production time, in days; α These are the fitting coefficients; μ g For the viscosity of natural gas, ; k For reservoir permeability, 10 -3 μm 2 ; k rg The relative permeability of the gas phase, taking into account the activity level of the water body; q sc The surface gas production of the gas well is expressed in m. 3 / d; B g This is the volume factor for natural gas; c The solubility of sulfur is expressed in kg / m³. 3 ; pFormation pressure, MPa; r Let be the radial distance, in meters, from any point in the formation to the wellbore. h The effective thickness of the gas reservoir is in meters (m). ϕ 0 represents the initial porosity; ρ s The density of solid sulfur is kg / m³ 3 ; S wi To bind water saturation; β For non-Darcy flow coefficients, m -1 ; ρ g The density of natural gas is kg / m³ 3 .

[0031] In some embodiments, in step S3 above, the relative permeability of the gas phase, taking into account the activity level of the water body, is: in, This refers to the relative permeability of the gas phase. This represents the relative gas-phase permeability corresponding to the bound water saturation. This represents the relative permeability of the aqueous phase corresponding to the residual gas saturation. These are intermediate parameters used in the calculation process; Corey index for aqueous phase; This refers to the Corey index in the gas phase.

[0032] In some implementations, in step S2 above, the second sulfur saturation equation considering the high-speed non-Darcy effect is: in, Sulfur saturation; Production time, in days; Here is the viscosity of natural gas, in mPa·s; For reservoir permeability, 10 -3 μm 2 ; The relative permeability of the gas phase, taking into account the activity level of the water body; For the surface gas production of the gas well, ; This is the volume factor for natural gas; For the solubility of sulfur, ; Formation pressure, MPa; Let be the radial distance, in meters, from any point in the formation to the wellbore. The effective thickness of the gas reservoir is in meters (m). Porosity of the gas reservoir; Density of solid sulfur ; For natural gas density ; To bind water saturation; For non-Darcy flow coefficients, .

[0033] Because real-world gas reservoir systems are extremely complex (e.g., heterogeneous pore structures and dynamic changes in reactions), attempting to completely and accurately describe all details would render the model unsolvable. Therefore, introducing validated and reasonable assumptions (such as simplifying porous media as a continuous system and basing them on the principle of mass balance) focuses on key influencing factors. This transforms a complex engineering problem into one that can be numerically integrated, while maintaining model accuracy. This allows for rapid, continuous, and real-time prediction of sulfur deposition in high-sulfur gas reservoirs.

[0034] In some embodiments, in the high-sulfur gas reservoirs corresponding to steps S1-S6 above, the gas phase satisfies the high-velocity non-Darcy flow law, and the liquid phase satisfies the Darcy flow law. In some embodiments, the predicted area for sulfur deposition in the gas reservoir is maintained under isothermal conditions during development. In some embodiments, the corresponding reservoir is horizontal, homogeneous, and of uniform thickness, and sulfur precipitates and settles within the reservoir. In some embodiments, the effects of gravity and capillary forces on fluid flow are ignored.

[0035] In some embodiments, in step S1 above, the sulfur saturation equation for sulfur in the porous medium is established as follows: in, This represents the change in sulfur volume per unit time due to sulfur deposition. The surface gas production of the gas well is expressed in m. 3 / d; ρ is the natural gas volume factor; c is the solubility of sulfur, kg / m³. 3 p represents formation pressure, in MPa. The density of solid sulfur is kg / m³ 3 t represents the production time, in days.

[0036] Due to the precipitation and deposition of sulfur, which occupies part of the pore space in the porous medium of the gas reservoir, the saturation degree of sulfur in the porous medium is: in, Sulfur saturation; Production time, in days; For the surface gas production of the gas well, ; This is the volume factor for natural gas; For the solubility of sulfur, ; Formation pressure, MPa; Let be the radial distance, in meters, from any point in the formation to the wellbore. The effective thickness of the gas reservoir is in meters (m). Porosity of the gas reservoir; Density of solid sulfur ; To bind water saturation.

[0037] The sulfur saturation in porous media described above can be transformed into sulfur saturation equation one: in, Sulfur saturation; Production time, in days; For the surface gas production of the gas well, ; This is the volume factor for natural gas; For the solubility of sulfur, ; Formation pressure, MPa; Let be the radial distance, in meters, from any point in the formation to the wellbore. The effective thickness of the gas reservoir is in meters (m). Porosity of the gas reservoir; Density of solid sulfur ; To bind water saturation.

[0038] Among them, the solubility relationship of sulfur in acidic fluids DC / dp The empirical relationship established by Roberts et al. based on Chrastil can be referenced, and regression analysis can be performed using relevant experimental data to determine the following: in, For the solubility of sulfur, ; Formation pressure, MPa; The molar mass of air is expressed in g / mol. The relative density of natural gas; The gas constant is... ; This is the natural gas deviation factor; , where K is the formation temperature.

[0039] In some implementations, in step S2 above, the high-speed non-Darcy effect is considered in the near-wellbore zone, and the gas flow in the porous medium is described using a binomial equation: in, Formation pressure, MPa; Let be the radial distance, in meters, from any point in the formation to the wellbore. Here is the viscosity of natural gas, in mPa·s; For reservoir permeability, 10 -3 μm 2 ; The relative permeability of the gas phase, taking into account the activity level of the water body; This refers to the gas phase seepage velocity; For natural gas density ; For non-Darcy flow coefficients, ; The molar mass of air is expressed in g / mol. The relative density of natural gas; The gas constant is... ; This is the natural gas deviation factor; , where K is the formation temperature.

[0040] The high-velocity non-Darcy flow coefficient of gas is calculated using the following formula: in, For reservoir permeability, 10 -3 μm 2 ; The relative permeability of the gas phase is taken into account the activity level of the water body.

[0041] For radial formations, gas travels a radial distance r The vapor flow velocity at that location is: in, For the surface gas production of the gas well, ; This is the volume factor for natural gas; Let be the radial distance, in meters, from any point in the formation to the wellbore. The effective thickness of the gas reservoir is in meters (m).

[0042] Based on the above gas phase seepage velocity v g Equations for gas flow dp / dr Substituting into the sulfur saturation equation one, we can obtain the sulfur saturation equation two above.

[0043] In some embodiments, in step S3 above, considering the porosity damage caused by sulfur deposition, the porosity after sulfur deposition is: in, This refers to the porosity of the gas reservoir after sulfur deposition. Different stages of sulfur precipitation; It is a natural constant; Initial porosity; These are the fitting coefficients; This represents the sulfur saturation level.

[0044] Based on the principle of mass balance, the formation water saturation is: in, Water saturation; For water intrusion volume, ; To calculate the cumulative water production, ; This is the formation water volume coefficient; Initial gas volume coefficient: Geological reserves, ; To bind water saturation.

[0045] Water storage volume coefficient ω It can be represented as: In the formula: The water volume coefficient; For water intrusion volume, ; To calculate the cumulative water production, ; This is the formation water volume coefficient; The initial gas volume coefficient; Geological reserves, .

[0046] The water storage volume factor and the degree of extraction are related as follows: in, B It is the water erosion constant; R c To determine the degree of extraction; ω This is the water volume coefficient.

[0047] Combine the above water saturation S w Water storage volume coefficient ω Water erosion constant B We obtain the equation regarding water saturation: in, B It is the water erosion constant; R cTo determine the degree of extraction; S wi To bind water saturation.

[0048] In the gas-water relative permeability curve, the ratio of the relative permeability of the two phases is... k rg / k rw The following equation applies to the relationship between water saturation and water content: in, k rg This refers to the relative permeability of the gas phase. k rw The relative permeability of the aqueous phase; a , b All are fitting coefficients; S w This represents the water saturation level.

[0049] When considering the condensate-to-gas ratio, the production water-to-gas ratio and relative permeability have the following relationship (Equation 2): in, This refers to the relative permeability of the gas phase. The relative permeability of the aqueous phase; Here is the viscosity of natural gas, in mPa·s; This is the volume factor for natural gas; The viscosity of formation water is given in mPa·s. This is the formation water volume coefficient; To produce a water-to-air ratio, ; For the condensate-to-gas ratio, .

[0050] By combining relation one and relation two, we obtain relation three: in, To produce a water-to-air ratio, ; For the condensate-to-gas ratio, ; Here is the viscosity of natural gas, in mPa·s; This is the volume factor for natural gas; The viscosity of formation water is given in mPa·s. Here, is the formation water volume factor; a and b are both fitting coefficients: It is a natural constant; This represents the water saturation level.

[0051] The proposed stable water production of gas wells in water-drive gas reservoirs is: In the formula: This refers to the underground water production of the gas well. ; For the effective permeability of the aqueous phase, 10 -3 μm 2 ; The effective thickness of the gas reservoir is in meters (m). Formation pressure, MPa; The bottom hole pressure is in MPa. The viscosity of formation water is given in mPa·s. These are the gas supply radius and the well radius, respectively, in meters; This is the epidermal coefficient.

[0052] The water production characteristics of a gas well can be characterized by the water-to-gas ratio. Water vapor in natural gas gradually condenses and is produced with the gas as temperature and pressure decrease. Considering the condensate water, the water production of a gas well is: in, For the surface gas production of the gas well, ; This is the formation water volume coefficient; To produce a water-to-air ratio, ; For the condensate-to-gas ratio, .

[0053] By combining the two different formulas for gas well water production mentioned above, the relative permeability of the aqueous phase can be obtained: in, The relative permeability of the aqueous phase; The viscosity of formation water is given in mPa·s. This is the formation water volume coefficient; For the surface gas production of the gas well, ; To produce a water-to-air ratio, ; For the condensate-to-gas ratio, ; For reservoir permeability, 10 -3 μm 2 ; The effective thickness of the gas reservoir is in meters (m). Formation pressure, MPa; The bottom hole pressure is in MPa. Let m be the gas supply radius and the well radius, respectively. This is the epidermal coefficient.

[0054] Substituting the relative permeability of the aqueous phase into the above equation and letting the right-hand side be... in, These are intermediate parameters used in the calculation process; Here is the viscosity of natural gas, in mPa·s; This is the volume factor for natural gas; For the surface gas production of the gas well, ; For reservoir permeability, 10 -3 μm 2 ; The effective thickness of the gas reservoir is given in meters (m); a and b are fitting coefficients. It is a natural constant; Water saturation; Formation pressure, MPa; The bottom hole pressure is in MPa. Let the gas supply radius and well radius be, respectively, in meters (m). This is the epidermal coefficient.

[0055] Substituting the above equation for water saturation into... ζ have to: in, These are intermediate parameters used in the calculation process; Here is the viscosity of natural gas, in mPa·s; This is the volume factor for natural gas; For the surface gas production of the gas well, ; For reservoir permeability, 10 -3 μm 2 ; The effective thickness of the gas reservoir is given in meters (m); a and b are fitting coefficients. It is a natural constant; It is the water erosion constant; To determine the degree of extraction; To bind water saturation; Formation pressure, MPa; The bottom hole pressure is in MPa. Let the gas supply radius and well radius be, respectively, in meters (m). This is the epidermal coefficient.

[0056] Since the relative permeability of air and water can be represented by the Brooks-Corey model: in, The relative permeability of the gas phase, taking into account the activity level of the water body; This represents the relative gas-phase permeability corresponding to the bound water saturation. Normalized wetting phase saturation; Corey index for aqueous phase; The Corey index is for the gas phase. The relative permeability of the aqueous phase; This represents the relative permeability of the water phase corresponding to the residual gas saturation.

[0057] The above normalized wetting phase saturation Determined by the following formula: in, S w Water saturation; S wi To bind water saturation; S gr This represents the residual gas saturation.

[0058] The above ζ , k rg and k rw This allows us to derive the gas-phase relative permeability that takes into account the water body's activity level. k rg .

[0059] In step S4 above, the relative permeability of the gas phase, taking into account the activity level of the water body, is... k rg Substituting the porosity after sulfur deposition into sulfur saturation equation two yields sulfur saturation equation three.

[0060] In step S5 above, by separating variables and performing numerical integration on sulfur saturation equation three, the above prediction model for sulfur saturation under different times, different radial distances, and different water activity levels can be obtained.

[0061] Based on the above derivation and the theories of material balance and gas-water seepage, the parameter (water intrusion constant) characterizing the activity level of formation water is introduced into the sulfur deposition prediction equation. A new sulfur deposition prediction model considering the high-velocity non-Darcy effect and the activity level of formation water is established, in order to provide theoretical support for the accurate prediction of sulfur saturation in high-sulfur gas reservoirs.

[0062] A second aspect of this application provides a readable storage medium storing a computer program. When executed, the computer program performs the sulfur deposition prediction method for high-sulfur gas reservoirs as described in any of the above embodiments. If the prediction method is implemented as a software functional unit and sold or used as an independent product, it can be stored in a readable storage medium. Based on this understanding, all or part of the processes of the methods described in the above embodiments can also be implemented by a computer program instructing related hardware. The computer program can be stored in the readable storage medium. When executed by a processor, the computer program can implement the steps of each method in the above embodiments. When the computer program is executed by a processor, the specific implementation of each step and the resulting technical effects are the same as in the aforementioned method embodiments. For the sake of brevity, any parts not mentioned in this embodiment can be referred to the corresponding content in the aforementioned method embodiments.

[0063] A third aspect of this application provides a device for predicting sulfur deposition in high-sulfur gas reservoirs, including a memory, a processor, and a terminal program stored in the memory and executable in the processor. The terminal program includes execution steps corresponding to the aforementioned method for predicting sulfur deposition in high-sulfur gas reservoirs. When the processor executes the terminal program, it implements the steps described in the method embodiments above. Figure 1 The steps shown; or, when the processor executes the terminal program, it implements the functions of each module / unit in the device. It should be understood that the device of this application can be implemented based on memory and processor, each memory being used to store a terminal program for executing the methods described above in this application, and the processor executing the terminal program, so that the high-sulfur gas reservoir sulfur deposition prediction device implements the methods of the above embodiments.

[0064] In some embodiments, the aforementioned sulfur deposition prediction device for high-sulfur gas reservoirs can be a desktop computer, laptop, industrial computer, PDA, tablet computer, or other mobile terminal, as well as a cloud server or other computer equipment, and is not limited to any particular operating system. The high-sulfur gas reservoir sulfur deposition prediction device may include, but is not limited to, a processor and memory. Those skilled in the art will understand that this hardware device does not constitute a limitation on the high-sulfur gas reservoir sulfur deposition prediction device; it may include more components, or combine certain components, or different components. For example, the high-sulfur gas reservoir sulfur deposition prediction device may also include input devices (keyboard), output devices (display), network access devices, buses, etc.

[0065] The following gas reservoir example illustrates this application: The formation pressure of a high-sulfur gas reservoir in the Sichuan Basin is known to be 48.25 MPa, the formation temperature is 93.24℃, the effective thickness is 35.90 m, the porosity is 6.3%, and the permeability is 4.37 x 10⁻⁶. -3 μm 2The gas reservoir production data was input into the model for calculation, using a 25x10... 4 m 3 During production at / d, the relationship between sulfur saturation and production time at a radial distance of 1m is shown in the figure. Figure 2 .analyze Figure 2 It is known that sulfur saturation increases with production time, and the rate of increase is even faster in the later stages. After 579 days of production, sulfur will completely block the flow channels. It is recommended to carry out desulfurization and deblocking measures every 2-3 years to mitigate the adverse effects of sulfur blockage on production.

[0066] Regarding the specific implementation methods of this application, it should be noted that: In the description of this application, embodiments of the present application can be implemented as electronic hardware, terminal application products, or a combination of computer software and electronic hardware, and are described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and terminal application products according to embodiments of the present application. It should be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by instructions. These instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The terminal program may be loaded onto a computer or stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to operate in a particular manner, causing the instructions of the terminal program to perform a series of operational steps to produce computer-implemented processing, produce an article of manufacture including instruction means, and realize the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0067] In the description of this application, the processor can be a central processing unit (CPU), a microcontroller (MCU), a graphics processing unit (GPU), a digital signal processor (DSP), an application-specific integrated circuit (ASIC), or a field-programmable gate array (FPGA). It can also be other general-purpose processors, programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor can be a microprocessor or any conventional processor. The processor is the control center of the X device / terminal equipment, connecting various parts of the entire X device / terminal equipment through various interfaces and lines. The memory can be used to store the aforementioned terminal programs and / or modules / units. The processor implements various functions of the X device / terminal equipment by running or executing the terminal programs and / or modules / units stored in the memory, and by calling data stored in the memory. The memory can mainly include a program storage area and a data storage area. The program storage area can store the operating system, at least one application program required for a function (such as image display function, fingerprint recognition function, etc.); the data storage area can store data created based on the use of the mobile phone (such as image data, text data, etc.). The aforementioned readable storage media include high-speed random access memory, and may also include non-volatile memory, such as hard disk, memory, optical storage, plug-in hard disk, memory card, security digital card, flash memory card, or at least one disk storage device, flash memory device, or other volatile solid-state storage device.

[0068] In the description of this application, the terminal program includes terminal program code, which may be in the form of source code, object code, executable file, or some intermediate form. Computer-readable storage media may include any entity or device capable of carrying terminal program code, such as a USB flash drive, portable hard drive, magnetic disk, optical disk, computer memory, read-only memory, random access memory, electrical carrier signals, telecommunication signals, software distribution media, or other recording media. The readable storage medium is a computer-readable storage medium, and the content it contains may be added to or removed according to the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice requirements, computer-readable storage media may not include electrical carrier signals and telecommunication signals.

[0069] In the description of this application, the applications involved in the embodiments of this application are software programs capable of performing one or more specific functions. Typically, multiple applications can be installed on a terminal device, such as camera applications, email applications, video applications, music applications, chat applications, WeChat, WeLink, etc. The aforementioned applications may be those pre-installed on the terminal device at the factory, or applications downloaded by the user from the network or obtained from other terminal devices during the use of the terminal device.

[0070] In the description of this application, the terms "comprising," "including," or any other variations thereof are intended to cover a non-exclusive inclusion, such that a process, method, apparatus, or readable storage medium that comprises a list of elements includes not only those elements but also other elements not expressly listed that conform to the concept of this application, or elements inherent to such a process, method, apparatus, or readable storage medium. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of additional elements in the process, method, apparatus, or readable storage medium that includes said element.

[0071] In the description of this application, the use of terms such as "some embodiments," "optional embodiments," "example," "specific example," "optional example," or "optional embodiment," etc., indicates that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application, but does not imply that these embodiments illustrate and describe all possible forms of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Furthermore, those skilled in the art can combine and integrate the different embodiments or examples described in this specification.

[0072] Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. Although embodiments of this application have been shown and described, various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of this application. Those skilled in the art will understand that various other specific changes and combinations of embodiments made based on the technical teachings disclosed in this application without departing from the essence of this application are still within the protection scope defined by the claims of this invention and their equivalent technical solutions.

[0073] Meanwhile, the technical solutions of the various embodiments can be combined with each other, but must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed in this application.

Claims

1. A method for predicting sulfur deposition in high-sulfur gas reservoirs, characterized in that, include: Based on the volume change of sulfur element caused by sulfur deposition per unit time, a sulfur saturation equation for sulfur in porous media in gas reservoirs is established. Based on high-speed non-Darcy seepage, a second sulfur saturation equation considering the high-speed non-Darcy effect is established. Based on the water production and relative permeability of the gas reservoir, and using the principle of material balance, the relative permeability of the gas phase, taking into account the activity level of the water body, is determined. Substituting the relative permeability of the gas phase into the second sulfur saturation equation, a third sulfur saturation equation is established, which considers the high-speed non-Darcy effect and the degree of water activity. Numerical integration is performed on the sulfur saturation equation three to obtain a prediction model for sulfur saturation; The sulfur deposition in the gas reservoir is calculated using the prediction model.

2. The method for predicting sulfur deposition in high-sulfur gas reservoirs according to claim 1, characterized in that, The third sulfur saturation equation, which considers the high-speed non-Darcy effect and the activity level of the water body, is as follows: ； in, Sulfur saturation; Production time, in days; Here is the viscosity of natural gas, in mPa·s; For reservoir permeability, 10 -3 μm 2 ; The relative permeability of the gas phase, taking into account the activity level of the water body; For the surface gas production of the gas well, ; This is the natural gas volume factor; For the solubility of sulfur, ; Formation pressure, MPa; Let be the radial distance, in meters, from any point in the formation to the wellbore. The effective thickness of the gas reservoir is in meters (m). Initial porosity; It is a natural constant; These are the fitting coefficients; Density of solid sulfur ; For natural gas density ; To bind water saturation; For non-Darcy flow coefficients, .

3. The method for predicting sulfur deposition in high-sulfur gas reservoirs according to claim 2, characterized in that, The prediction model is as follows: ； in, ; .

4. The method for predicting sulfur deposition in high-sulfur gas reservoirs according to claim 1, characterized in that, The relative permeability of the gas phase, taking into account the activity level of the water body, is: ； in, This refers to the relative permeability of the gas phase. This represents the relative gas-phase permeability corresponding to the bound water saturation. This represents the relative permeability of the aqueous phase corresponding to the residual gas saturation. These are intermediate parameters used in the calculation process; Corey index for aqueous phase; This refers to the Corey index in the gas phase.

5. The method for predicting sulfur deposition in high-sulfur gas reservoirs according to claim 1, characterized in that, The second sulfur saturation equation considering the high-speed non-Darcy effect is as follows: ； in, Sulfur saturation; Production time, in days; Here is the viscosity of natural gas, in mPa·s; For reservoir permeability, 10 -3 μm 2 ; The relative permeability of the gas phase, taking into account the activity level of the water body; For the surface gas production of the gas well, ; This is the natural gas volume factor; For the solubility of sulfur, ; Formation pressure, MPa; Let be the radial distance, in meters, from any point in the formation to the wellbore. The effective thickness of the gas reservoir is in meters (m). Porosity of the gas reservoir; Density of solid sulfur ; For natural gas density ; To bind water saturation; For non-Darcy flow coefficients, .

6. The method for predicting sulfur deposition in high-sulfur gas reservoirs according to claim 1, characterized in that, The gas phase in the gas reservoir satisfies the law of high-velocity non-Darcy flow, while the liquid phase satisfies the law of Darcy flow.

7. The method for predicting sulfur deposition in high-sulfur gas reservoirs according to claim 1, characterized in that, The predicted area for sulfur deposition in the gas reservoir is kept under constant temperature conditions during development.

8. The method for predicting sulfur deposition in high-sulfur gas reservoirs according to claim 1, characterized in that, The gas reservoir is horizontal, homogeneous, and of uniform thickness, and sulfur precipitates and settles in the reservoir.

9. A readable storage medium storing a computer program, characterized in that, When the computer program is executed, it performs the sulfur deposition prediction method for high-sulfur gas reservoirs as described in any one of claims 1-8.

10. A device for predicting sulfur deposition in high-sulfur gas reservoirs, comprising a memory, a processor, and a terminal program stored in the memory and capable of running in the processor, characterized in that, The terminal program includes the execution steps corresponding to the sulfur deposition prediction method for high-sulfur gas reservoirs as described in any one of claims 1-8.

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