High-sulfur-content gas reservoir sulfur fixation deposition simulation method

Abstract

The invention relates to a high-sulfur-content gas reservoir sulfur fixation deposition simulation method, and belongs to the technical field of oil and gas field exploration and development.The method comprises the steps that a gas-sulfur fixation relative permeability curve, a state equation reflecting sulfur precipitation fluid properties and a permeability damage model are obtained through experiments on the basis that a geologic model is established, and the results are input into the geologic model; and establishing a sulfur-fixation deposition numerical model considering the real characteristics of the reservoir, and performing sulfur-fixation deposition simulation on the reservoir by using the sulfur-fixation deposition numerical model considering the real characteristics of the reservoir. According to the method, multiple influence factors are comprehensively considered to simulate the sulfur-fixation deposition process, and the problem that the simulation effect is not accurate due to the fact that few influence factors are considered when the sulfur deposition condition is simulated in the prior art is solved.

Description

Technical Field

[0001] The invention relates to the technical field of oil and gas field exploration and development, and in particular to a method for simulating sulfur deposition in a high-sulfur gas reservoir. Background Art

[0002] China is rich in sour natural gas resources. High-sulfur gas reservoirs are widely distributed in the Sichuan Basin. It is of great significance to achieve efficient development of such gas reservoirs.

[0003] During the production and development of high-sulfur gas reservoirs, elemental sulfur precipitates in the reservoir as the pressure decreases. When the formation temperature is lower than 112°C, elemental sulfur precipitates in solid form, causing damage to the formation porosity and permeability, reducing gas well production capacity and gas reservoir recovery. Therefore, quantitatively predicting the precipitation dynamics of elemental sulfur during the development of high-sulfur gas reservoirs is an important prerequisite for achieving efficient development of high-sulfur gas reservoirs.

[0004] Traditional sulfur deposition simulation is based on theoretical formulas, assuming that the reservoir is homogeneous, that is, the parameters characterizing the reservoir properties (such as permeability and porosity) are set to a constant. Then, a mathematical model is used to calculate the impact of sulfur deposition on production. This method cannot take into account the true characteristics of the reservoir and cannot reflect the law of sulfur deposition under formation conditions.

[0005] For example, Zhang Yong, author of "Numerical Model of Gas-Solid Two-Phase Multi-Component in High-Sulfur Gas Reservoirs" in the 8th issue of Natural Gas Industry in 2006, disclosed the establishment of a three-dimensional gas-solid two-phase multi-component mathematical model and used the Carman-Kozeny deposition damage model to describe the damage of sulfur deposition to formation porosity and permeability.

[0006] Porosity Damage Model:

[0007]

[0008] Penetration damage model:

[0009]

[0010] Where, K is the permeability; is the porosity; is the initial porosity; K0 is the initial permeability; a, n, and m are the calculation coefficients in the sedimentation damage model.

[0011] Zhang Yong, author of "Numerical Simulation Study on the Impact of Sulfur Deposition on the Productivity of High-Sulfur Gas Reservoirs" in the 6th issue of Natural Gas Industry in 2007, disclosed the establishment of a mathematical model for the migration and deposition of sulfur particles in high-sulfur gas reservoirs, and simulated the impact of sulfur deposition on gas reservoir productivity.

[0012] Porosity Damage Model:

[0013]

[0014] Penetration damage model:

[0015]

[0016] in, is the porosity; is the initial porosity; V s is the volume of precipitated sulfur phase; V is the rock volume; K is the permeability; f p is the friction coefficient of the blocked channel; f np is the friction coefficient of the non-blocked channel; K p0 is the initial permeability of the blocked channel; K np0 is the initial permeability of the non-blocked channel; ε p is the porosity reduction value of the blocked channel; ε np is the porosity reduction value of the non-blocked channel; a and b are calculation coefficients; n1 is the permeability reduction coefficient of the blocked channel.

[0017] In the article "Damage of Elemental Sulfur Deposition to Reservoirs in High-Sulfur Gas Reservoirs" published in Petroleum Exploration and Development, Issue 6, 2005, Zeng Ping published an analysis of the characteristics of elemental sulfur deposition and the damage to reservoir physical properties during the development of high-sulfur gas reservoirs based on a simulation model of the damage of elemental sulfur deposition to reservoirs.

[0018] The relationship between porosity and time can be expressed as:

[0019]

[0020] The relationship between permeability and time is as follows:

[0021] K / K0=1+[amq 2 / (h 2 r 2 )](t+aτS s )

[0022] Where:

[0023]

[0024] in, is the porosity; S s is the sulfur saturation of the formation; τ is the delay time; q is the gas production; h is the effective thickness of the reservoir; r is the distance from a point in the formation to the center of the well; a is an empirical constant; K is the effective permeability; K0 is the initial permeability; t is the production time; C is the solubility of elemental sulfur; p is the pressure; T is the temperature; μ g is the gas viscosity; B g is the gas volume coefficient; δ is the non-Darcy flow correction coefficient.

[0025] The above articles all assume that the reservoir permeability and porosity are constants, and then calculate the impact of fixed sulfur deposition on production and development. Summary of the invention

[0026] The purpose of the present invention is to provide a method for simulating sulfur deposition in a high-sulfur gas reservoir, so as to solve the problem of inaccurate simulation effect caused by insufficient consideration of influencing factors when simulating sulfur deposition in the prior art.

[0027] In order to solve the above technical problems, the present invention provides a method for simulating sulfur deposition in a high-sulfur gas reservoir, comprising the following steps:

[0028] 1) Establish a geological model for the area to be evaluated;

[0029] 2) Using the rock samples of the target layer in the study area to obtain the gas-liquid sulfur phase permeability curve, the gas-liquid sulfur phase permeability curve is processed to obtain the gas-solid sulfur phase permeability curve;

[0030] 3) Using gas samples from the study area to obtain the equation of state that reflects the fluid properties of sulfur precipitation;

[0031] 4) Using the rock samples of the target layer in the study area to obtain the relationship data between rock permeability and fixed sulfur saturation, the data on the relationship between rock permeability and fixed sulfur saturation were processed to obtain the permeability damage model;

[0032] 5) The gas-solid sulfur phase permeability curve, the state equation reflecting the fluid properties of sulfur precipitation and the permeability damage mathematical model are input into the geological model to establish a solid sulfur deposition numerical model that considers the real characteristics of the reservoir, so as to use the solid sulfur deposition numerical model that considers the real characteristics of the reservoir to simulate the solid sulfur deposition in the reservoir.

[0033] The beneficial effect of the above technical solution is that a more accurate solid sulfur deposition numerical model considering the real characteristics of the reservoir is established by comprehensively considering the gas-solid sulfur phase permeability curve, the fluid properties of sulfur precipitation and the permeability damage mathematical model.

[0034] Furthermore, the relevant parameters for establishing the geological model of the evaluation area in step 1) include the structure, reservoir, stratification data and logging interpretation results of the study area.

[0035] The beneficial effects of the above technical solution are: firstly, a geological model including the reservoir is established to facilitate the subsequent establishment of a more accurate sulfur-fixing deposition numerical model that takes into account the real characteristics of the reservoir.

[0036] Furthermore, in step 2), the processing performed on the gas-liquid sulfur phase permeability curve is to set the liquid sulfur relative permeability value in the gas-liquid sulfur phase permeability curve to 0, so as to obtain a gas-solid sulfur phase permeability curve.

[0037] The beneficial effect of the above technical solution is that the gas-solid sulfur phase permeability curve is obtained by setting the liquid sulfur relative permeability value in the gas-liquid sulfur phase permeability curve.

[0038] Furthermore, in step 3), the method for obtaining the state equation reflecting the fluid properties of sulfur precipitation is to use gas samples in the study area to carry out high-pressure physical property test experiments and sulfur solubility experiments, obtain gas high-pressure physical property data, sulfur solubility change data with pressure and sulfur precipitation critical pressure, calculate the volume fraction of the precipitated sulfur phase based on the sulfur solubility change data with pressure, calculate the actual mole fraction of each component in the natural gas and the actual mole fraction of elemental sulfur under original conditions based on the gas high-pressure physical property data, regard elemental sulfur as a heavy component, input the actual mole fraction of each component in the natural gas and the actual mole fraction of elemental sulfur into the PVT software, fit the precipitated sulfur phase volume fraction and the sulfur precipitation critical pressure through the PVT software, adjust the state equation parameters through the PVT software to make the calculation results match the actual values ​​measured in the laboratory, and finally output the state equation reflecting the fluid properties of sulfur precipitation.

[0039] The beneficial effect of the above technical solution is that the state equation reflecting the fluid properties of sulfur precipitation is obtained, which facilitates the subsequent establishment of a fixed sulfur deposition numerical model that takes into account the real characteristics of the reservoir.

[0040] Furthermore, in step 4), the specific method for processing the data on the relationship between rock permeability and fixed sulfur saturation is to draw a scatter plot of permeability and fixed sulfur saturation, select a curve similar to the scatter distribution, obtain a function expression of the curve, adjust the coefficients in the function expression, make the curve consistent with the trend of the scatter plot, and obtain the function expression corresponding to the scatter plot, which is the permeability damage model.

[0041] The beneficial effect of the above technical solution is that obtaining the permeability damage model facilitates the subsequent establishment of a fixed sulfur deposition numerical model that takes into account the real characteristics of the reservoir.

[0042] Furthermore, the formula for calculating the volume fraction of the precipitated sulfur phase is:

[0043]

[0044] Among them, S wc B is bound water saturation; g is the natural gas volume coefficient; ρ sul is the sulfur density; R s1 , R s2 These are the solubility of sulfur in natural gas under different pressure conditions.

[0045] The beneficial effect of the above technical solution is that the volume fraction of the precipitated sulfur phase is calculated, which facilitates the subsequent calculation of the state equation reflecting the fluid properties of sulfur precipitation.

[0046] Furthermore, the steps for calculating the actual molar fraction of each component in natural gas and the actual molar fraction of elemental sulfur under the original conditions are as follows: Assume that the natural gas composition has n components, and the molar fraction of each component is x i , then the actual number of components in natural gas is n+1, and the actual molar fraction of each component in 1 mol of natural gas is X i for:

[0047]

[0048] The actual mole fraction of elemental sulfur is X n+1 for:

[0049]

[0050] Among them, the actual number of moles of elemental sulfur is:

[0051]

[0052] Among them, n sul is the number of moles of elemental sulfur; V m is the molar volume of natural gas; R si is the concentration of elemental sulfur in natural gas under original conditions; M sul is the molar mass of elemental sulfur.

[0053] The beneficial effect of the above technical solution is: obtaining the actual mole fraction of each component in the natural gas and the actual mole fraction of elemental sulfur, which is convenient for the subsequent calculation of the state equation reflecting the fluid properties of sulfur precipitation. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Figure 1 It is a technical solution flow chart of the method for simulating sulfur deposition in a high-sulfur gas reservoir of the present invention;

[0055] Figure 2 is a permeability model of an embodiment of the present invention;

[0056] Figure 3 is a porosity model of an embodiment of the present invention;

[0057] Figure 4 is a gas-liquid sulfur phase permeability curve of an embodiment of the present invention;

[0058] Figure 5 is a gas-solid sulfur phase permeability curve of an embodiment of the present invention;

[0059] Figure 6 is a fitting diagram of the volume fraction of the precipitated sulfur phase of an embodiment of the present invention;

[0060] Figure 7 is a fitting diagram of the critical pressure of sulfur precipitation of an embodiment of the present invention;

[0061] Figure 8 is a scatter plot of rock permeability and fixed sulfur saturation in an embodiment of the present invention;

[0062] Fig. 9 is a fitting curve of rock permeability and fixed sulfur saturation in an embodiment of the present invention;

[0063] Fig.10 3 is a sulfur fixation saturation distribution diagram of an embodiment of the present invention. DETAILED DESCRIPTION

[0064] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention is further described in detail below with reference to the accompanying drawings and embodiments.

[0065] Example of simulation method for solid sulfur deposition in high-sulfur gas reservoir:

[0066] The present invention proposes an effective simulation method for the prior art that fails to consider the true reservoir characteristics and thus fails to reflect the law of solid sulfur deposition under formation conditions. The flow chart of the method is as follows: Figure 1 As shown, the specific implementation steps of this method are as follows:

[0067] 1) Use the structural, reservoir, stratification data and logging interpretation results of the study area to establish a geological model for the area to be evaluated. The specific method of constructing a geological model is to use conventional structural modeling technology to establish a structural model under the structural modeling module; on the basis of the single well sedimentary microfacies division, establish a plan view of different microfacies in the small layer, and use a deterministic modeling method to establish a sedimentary microfacies model; use the logging interpretation results data, through statistical analysis of the standard deviation, probability distribution, and variogram of each parameter in each phase, under the control of the conditional well, use a random simulation method to perform sequential indicator simulation to obtain a lithofacies model; on the basis of the established structural model, assign values ​​to each three-dimensional grid according to a certain interpolation or simulation method, establish a three-dimensional distribution model of reservoir attributes, and finally obtain the required geological model.

[0068] 2) The gas-liquid sulfur phase permeability curve was obtained using the rock samples of the target layer in the study area, and the relative permeability value of liquid sulfur in the gas-liquid sulfur phase permeability curve was set to 0 to obtain the gas-solid sulfur phase permeability curve.

[0069] 3) Carry out high-pressure physical property test experiments and sulfur solubility experiments using gas samples from the study area to obtain gas high-pressure physical property data, sulfur solubility variation data with pressure, and sulfur precipitation critical pressure. Based on the sulfur solubility variation data with pressure, calculate the volume fraction of the precipitated sulfur phase. The sulfur phase volume fraction formula is:

[0070]

[0071] Among them, S wc B is bound water saturation; gis the natural gas volume coefficient; ρ sul is the sulfur density; R s1 , R s2 These are the solubility of sulfur in natural gas under different pressure conditions.

[0072] Based on the high-pressure physical property data of gas, the actual mole fraction of each component in natural gas and the actual mole fraction of elemental sulfur under the original conditions are calculated. The steps for calculating the actual mole fraction of each component in natural gas and the actual mole fraction of elemental sulfur under the original conditions are as follows: Assume that the natural gas composition has n components, and the mole fraction of each component is x i , then the actual number of components in natural gas is n+1, and the actual molar fraction of each component in 1 mol of natural gas is X i for:

[0073]

[0074] The actual mole fraction of elemental sulfur is X n+1 for:

[0075]

[0076] Among them, the actual number of moles of elemental sulfur is:

[0077]

[0078] Among them, n sul is the number of moles of elemental sulfur; V m is the molar volume of natural gas; R si is the concentration of elemental sulfur in natural gas under original conditions; M sul is the molar mass of elemental sulfur.

[0079] Elemental sulfur is regarded as a heavy component, and the actual mole fraction of each component in natural gas and the actual mole fraction of elemental sulfur are input into the PVT software. The volume fraction of the precipitated sulfur phase and the critical pressure of sulfur precipitation are fitted by the PVT software. The state equation parameters are adjusted by the PVT software to make the calculation results match the actual values ​​measured in the laboratory, and finally the state equation reflecting the fluid properties of sulfur precipitation is output.

[0080] 4) Use the rock samples of the target layer in the study area to obtain the relationship data between rock permeability and fixed sulfur saturation, draw a scatter plot of permeability and fixed sulfur saturation, select a curve similar to the scatter distribution, obtain the function expression of the curve, adjust the coefficients in the function expression to make the curve consistent with the trend of the scatter plot, obtain the function expression corresponding to the scatter plot, and obtain the permeability damage model.

[0081] 5) Based on the geological model, the data loading function of the digital model module is used to input the gas-solid sulfur phase permeability curve and the state equation reflecting the fluid properties of sulfur precipitation; the permeability damage mathematical model is added to the Schedule file using keywords. Finally, a numerical model that can reflect the spatial variation of reservoir fluid properties and rock fluid seepage characteristics is obtained, so as to simulate reservoir solid sulfur deposition using the solid sulfur deposition numerical model that considers the real characteristics of the reservoir.

[0082] On the basis of the establishment of the geological model, based on core experiments, high-pressure physical property experiments and sulfur solubility experiments, the experimental results were fitted and input into the geological model to perform time-varying permeability simulation to characterize the solid sulfur deposition process and law. The geological model can accurately reflect the actual geological parameters of the reservoir, including permeability, porosity, etc.; core experiments, high-pressure physical property experiments, and sulfur solubility experiments can accurately reflect the fluid seepage characteristics, fluid phase and properties in the formation; at the same time, the permeability damage mathematical model was added to perform time-varying permeability simulation to characterize the damage of solid sulfur deposition to the reservoir permeability.

[0083] The following is a further description of the implementation method of the present invention by taking a high-sulfur gas reservoir in Sichuan, my country as an example. Figure 1 It is a flow chart of the technical solution of the present invention, and the specific steps of the present invention are as follows:

[0084] 1. Establish a geological model for the area to be evaluated.

[0085] The geological model is established using the data of the study area's structure, reservoir, stratification data, and logging interpretation results. The geological model includes permeability models, porosity models (such as Figure 2 , Figure 3 They are the permeability model and porosity model in the geological model of the area, respectively, which can reflect the real characteristics of the reservoir.

[0086] 2. Use rock samples and gas samples from the target layer in the study area to carry out seepage experiments and high-pressure physical property experiments to obtain gas-liquid sulfur phase permeability curves, gas high-pressure physical property data, sulfur solubility data, sulfur precipitation critical pressure, and permeability and solid sulfur saturation relationship data.

[0087] 2.1 The gas-liquid sulfur phase permeability experiment was carried out using the rock samples of the target layer in the study area to obtain the gas-liquid sulfur phase permeability curve. The gas-liquid sulfur phase permeability curve is a relationship curve between the relative permeability of gas and liquid sulfur phases and gas saturation, which can comprehensively reflect the seepage characteristics of gas and liquid sulfur phases. Figure 4 This is the gas-liquid sulfur permeability curve obtained in the experiment in this example.

[0088] 2.2 Using the gas samples in the study area, high-pressure physical property test experiments and sulfur solubility experiments were carried out to obtain gas high-pressure physical property data, sulfur solubility change data with pressure, and sulfur precipitation critical pressure. Table 1 and Table 2 are the high-pressure physical property data and sulfur solubility change data obtained in the experiment in this example. The experiment shows that the critical pressure of sulfur precipitation in this area is 21MPa.

[0089] Table 1

[0090]

[0091] Table 2

[0092]

[0093] 2.3 Using the rock samples of the target layer in the study area, the relationship experiment between rock permeability and fixed sulfur saturation was carried out to obtain the relationship data between rock permeability and fixed sulfur saturation. Table 3 shows the relationship data between rock permeability and fixed sulfur saturation obtained in the experiment in this example.

[0094] Table 3

[0095]

[0096]

[0097] 3. By correcting and fitting the experimental data, the gas-solid sulfur phase permeability curve, PVTi data and permeability damage mathematical model are obtained.

[0098] 3.1 Since solid sulfur does not flow in the reservoir, the relative permeability of liquid sulfur in the gas-liquid sulfur phase permeability curve is set to 0 to achieve the purpose of making the sulfur phase immobile, reflecting the seepage characteristics of gas-solid sulfur, and obtaining the gas-solid sulfur phase permeability curve. Figure 5 This is the gas-solid sulfur phase permeability curve obtained after correction.

[0099] 3.2 Based on the data of sulfur solubility changing with pressure, the empirical formula is used to calculate the volume fraction of the precipitated sulfur phase. Based on the high-pressure physical property data of the gas, the actual mole fraction of each component in the natural gas and the actual mole fraction of elemental sulfur under the original conditions are calculated. Then, elemental sulfur is regarded as a heavy component, and the volume fraction of the precipitated sulfur phase and the critical pressure of sulfur precipitation are fitted to finally obtain the PVTi data. The PVTi data is used to characterize the fluid properties in the formation.

[0100] The empirical formula for the volume fraction of precipitated sulfur phase is:

[0101]

[0102] Among them, S wc B is bound water saturation; g is the natural gas volume coefficient, in m 3 / m3 ρ sul is the sulfur density, in kg / m 3 ; R s1 and R s2 These are the solubility of sulfur in natural gas under different pressure conditions.

[0103] The steps to calculate the actual mole fraction of each component in natural gas and the actual mole fraction of elemental sulfur are:

[0104] Assume that natural gas consists of n components and the molar fraction of each component is x. i , then the actual number of components in natural gas is n+1, and the actual molar fraction of each component in 1 mol of natural gas is X i for:

[0105]

[0106] The actual mole fraction of elemental sulfur is X n+1 for:

[0107]

[0108] Among them, the number of moles of elemental sulfur n sul for:

[0109]

[0110] Among them, n sul is the number of moles of elemental sulfur, in mol; V m is the molar volume of natural gas, in m 3 / mol; R si is the concentration of elemental sulfur in natural gas under original conditions, in g / m 3 ;M sul is the molar mass of elemental sulfur, in g / mol.

[0111] In this example, the natural gas is composed of 7 components, plus elemental sulfur, the actual number of components is 8. The actual molar fractions of the components in the natural gas in this example are calculated as shown in Table 4.

[0112] Table 4

[0113] Components Mole fraction (mol%) <![CDATA[H2S]]> 16.054 <![CDATA[N2]]> 1.097 <![CDATA[H2]]> 1.232 He 0.010 <![CDATA[CO2]]> 9.575 <![CDATA[C1]]> 71.989 <![CDATA[C2]]> 0.023 S 0.020

[0114] When fitting the volume fraction of the precipitated sulfur phase and the critical pressure of sulfur precipitation, the state equation parameters are adjusted with the help of PVT software so that the results calculated by the PVT software match the actual values.

[0115] The real gas state equation is:

[0116] PV=ZRT

[0117] Where P is the gas pressure in Pa; V is the gas volume in m 3 ; T is the absolute temperature of the gas, the unit is K; R is the gas constant, the unit is J / (kg·k); Z is the compressibility factor.

[0118] Figure 6 , Figure 7 They are the fitting diagrams of the volume fraction of the precipitated sulfur phase and the critical pressure of sulfur precipitation in this example, respectively.

[0119] 3.3 Fit the data of the relationship between rock permeability and fixed sulfur saturation to obtain a mathematical model of permeability damage, which is used to characterize the damage of fixed sulfur deposition to reservoir permeability.

[0120] Draw a scatter plot of permeability and fixed sulfur saturation, select the appropriate curve type, give the function expression of the corresponding curve type, adjust the coefficients in the function expression to make the curve consistent with the trend of the scatter plot, and obtain the function expression corresponding to the scatter plot. This function expression is the permeability damage mathematical model.

[0121] The scatter plot and fitting curve of rock permeability and fixed sulfur saturation in this example are shown in Figure 8 , Fig. 9 ; The obtained mathematical expression, that is, the permeability damage mathematical model is:

[0122]

[0123] Among them, K s is the rock permeability, K0 is the initial rock permeability, S s is the sulfur saturation.

[0124] 4. Input the gas-solid sulfur phase permeability curve, PVTi data and permeability damage mathematical model into the geological model.

[0125] 4.1 Input the gas-solid sulfur phase permeability curve and PVTi data into the geological model.

[0126] 4.2 Add the permeability time-varying keyword, input the permeability damage mathematical model into the geological model, establish a fixed sulfur deposition numerical model that takes into account the real characteristics of the reservoir, and perform permeability time-varying simulation. Clarify the fixed sulfur deposition law. Fig.10 This is the fixed sulfur saturation distribution diagram obtained by simulation in this example.

[0127] The research results were used to predict sulfur deposition in two wells in the block. After sulfur dissolution measures were taken, the production of the wells increased, indicating that the method of predicting fixed sulfur deposition using the present invention is effective.

[0128] Combined with the analysis of examples, it is shown that the present invention can quantitatively predict the state of solid sulfur deposition, realize accurate and quantitative evaluation of solid sulfur deposition in high-sulfur gas reservoirs, and provide guidance for the efficient development of high-sulfur gas reservoirs. The present invention provides a way of thinking and method for simulating solid sulfur deposition in high-sulfur gas reservoirs, and provides a basis for efficient and accurate prediction of solid sulfur deposition in gas reservoirs of the same type.

[0129] Specific implementation methods are given above, but the present invention is not limited to the described implementation methods. The basic idea of ​​the present invention lies in the above basic scheme. For ordinary technicians in this field, it does not take creative work to design various deformed models, formulas, and parameters according to the teachings of the present invention. Changes, modifications, substitutions, and variations of the implementation methods without departing from the principles and spirit of the present invention still fall within the scope of protection of the present invention.

Claims

1. A method for simulating sulfur deposition in a high-sulfur gas reservoir, characterized in that: The following steps are involved: 1) Establish a geological model for the area to be evaluated; 2) Using the rock samples of the target layer in the study area to obtain the gas-liquid sulfur phase permeability curve, the gas-liquid sulfur phase permeability curve is processed to obtain the gas-solid sulfur phase permeability curve; 3) Using gas samples from the study area to obtain the equation of state that reflects the fluid properties of sulfur precipitation; 4) Using the rock samples of the target layer in the study area to obtain the relationship data between rock permeability and fixed sulfur saturation, the data on the relationship between rock permeability and fixed sulfur saturation were processed to obtain the permeability damage model; 5) The gas-solid sulfur phase permeability curve, the state equation reflecting the fluid properties of sulfur precipitation and the permeability damage mathematical model are input into the geological model to establish a solid sulfur deposition numerical model that considers the real characteristics of the reservoir, so as to use the solid sulfur deposition numerical model that considers the real characteristics of the reservoir to simulate the solid sulfur deposition in the reservoir.

2. The method for simulating sulfur deposition in a high-sulfur gas reservoir according to claim 1, characterized in that: The relevant parameters for establishing the geological model of the evaluation area in step 1) include the structure, reservoir, stratification data and logging interpretation results of the study area.

3. The method for simulating sulfur deposition in a high-sulfur gas reservoir according to claim 1, characterized in that: The processing performed on the gas-liquid sulfur phase permeability curve in step 2) is to set the liquid sulfur relative permeability value in the gas-liquid sulfur phase permeability curve to 0, so as to obtain a gas-solid sulfur phase permeability curve.

4. The method for simulating sulfur deposition in a high-sulfur gas reservoir according to claim 1, characterized in that: The method for obtaining the state equation reflecting the fluid properties of sulfur precipitation in step 3) is to use the gas samples in the study area to carry out high-pressure physical property test experiments and sulfur solubility experiments, obtain gas high-pressure physical property data, sulfur solubility change data with pressure and sulfur precipitation critical pressure, calculate the volume fraction of the precipitated sulfur phase based on the sulfur solubility change data with pressure, calculate the actual mole fraction of each component in the natural gas and the actual mole fraction of elemental sulfur under original conditions based on the gas high-pressure physical property data, regard elemental sulfur as a heavy component, input the actual mole fraction of each component in the natural gas and the actual mole fraction of elemental sulfur into the PVT software, fit the precipitated sulfur phase volume fraction and the sulfur precipitation critical pressure through the PVT software, adjust the state equation parameters through the PVT software to make the calculation results match the actual values ​​measured in the laboratory, and finally output the state equation reflecting the fluid properties of sulfur precipitation.

5. The method for simulating sulfur deposition in a high-sulfur gas reservoir according to claim 1, characterized in that: The specific method for processing the data on the relationship between rock permeability and fixed sulfur saturation in step 4) is to draw a scatter plot of permeability and fixed sulfur saturation, select a curve similar to the scatter distribution, obtain a function expression of the curve, adjust the coefficients in the function expression, make the curve consistent with the trend of the scatter plot, and obtain the function expression corresponding to the scatter plot, which is the permeability damage model.

6. The method for simulating sulfur deposition in a high-sulfur gas reservoir according to claim 4, characterized in that: The formula for calculating the volume fraction of precipitated sulfur phase is: Among them, S wc B is bound water saturation; g is the natural gas volume coefficient; ρ sul is the sulfur density; R s1 , R s2 These are the solubility of sulfur in natural gas under different pressure conditions.

7. The method for simulating sulfur deposition in a high-sulfur gas reservoir according to claim 4, characterized in that: The steps to calculate the actual mole fraction of each component in natural gas and the actual mole fraction of elemental sulfur under original conditions are as follows: Assume that natural gas has n components and the mole fraction of each component is x i , then the actual number of components in natural gas is n+1, and the actual molar fraction of each component in 1 mol of natural gas is X i for: The actual mole fraction of elemental sulfur is X n+1 for: Among them, the actual number of moles of elemental sulfur is: Among them, n sul is the number of moles of elemental sulfur; V m is the molar volume of natural gas; R si is the concentration of elemental sulfur in natural gas under original conditions; M sul is the molar mass of elemental sulfur.

Images