A numerical simulation method and system for flow control and water control well completion of an acid gas reservoir

Abstract

The application provides an acid gas reservoir flow regulation water control well completion numerical simulation method and system, and belongs to the field of acid gas reservoir horizontal well completion. The acid gas reservoir flow regulation water control well completion numerical simulation method considers the influence of sulfur deposition on water control in the acid gas reservoir, simulates the development characteristics of the acid gas reservoir, optimizes the self-adaptive flow regulation water control screen pipe parameters of the acid gas reservoir, and further enhances the development effect of the acid gas reservoir flow regulation water control well completion, realizes water control and gas stabilization of the acid gas reservoir, improves the recovery rate of the acid gas reservoir, and can provide guidance for the flow regulation water control well completion design and application in the acid gas reservoir.

Description

Technical Field

[0001] This invention belongs to the field of horizontal well completion in acidic gas reservoirs, specifically relating to a numerical simulation method and system for flow regulation and water control completion in acidic gas reservoirs, which is particularly suitable for flow regulation and water control completion in horizontal wells of acidic gas reservoirs with edge and bottom water. Background Technology

[0002] Acidic gas reservoirs are widely distributed worldwide, with over 400 commercially viable reservoirs discovered globally. The presence of hydrogen sulfide in these reservoirs makes them corrosive, plugging, and highly toxic, increasing the difficulty of their development. Elemental sulfur is dissolved in the gas phase. As extraction progresses, the reservoir pressure gradually decreases, causing elemental sulfur to continuously precipitate from the gas. If the reservoir temperature is below the freezing point of elemental sulfur, the precipitated sulfur is solid. Some of this solid sulfur deposits on the surface of reservoir pores, blocking gas flow channels and leading to a decrease in reservoir porosity and permeability.

[0003] For acidic gas reservoirs with edge and bottom water, produced water can cause edge and bottom water to intrude into the wellbore, leading to liquid accumulation or even shutdown of production, thus increasing development difficulty. For the development of acidic water-bearing gas reservoirs, it is necessary to implement effective measures to prevent corrosion and blockage of acidic gases, while simultaneously controlling water and stabilizing gas flow.

[0004] Domestic and international research and applications have shown that using flow regulation and water control to balance the production profile is an effective method to improve horizontal well production and control edge and bottom water intrusion. A representative flow regulation and water control technology is adaptive flow regulation and water control technology, which enhances the suppression of adverse fluid intrusion, achieving the goals of delaying adverse fluid intrusion, increasing water sweep efficiency, extending gas well production cycles, and improving gas reservoir recovery.

[0005] Chinese patent publication CN111378423A discloses a water control agent for high-sulfur natural gas wells in high-water-cut, low-permeability gas reservoirs and its preparation method. This method utilizes nanofluids, featuring a simple process, easy operation, low cost, and high safety. The addition of dispersants, composite crosslinking agents, and reinforcing agents significantly improves production. However, the proposed water control agent and its preparation method rely on chemical plugging principles to seal water-producing formations and prevent formation water from entering the wellbore. Furthermore, this water control agent lacks fluid selectivity and cannot achieve adaptive flow regulation and water control. Additionally, this patent does not propose a design method for flow regulation and water control completion in acidic gas reservoirs.

[0006] Currently, there is no design method for flow regulation and water control completions in acidic gas reservoirs, which cannot guide the optimization design of flow regulation and water control completions in acidic gas reservoirs, resulting in the ineffective application of flow regulation and water control technology in acidic gas reservoirs. Summary of the Invention

[0007] The purpose of this invention is to solve the problems existing in the prior art and provide a numerical simulation method and system for flow regulation and water control completion in acidic gas reservoirs. This method rationally designs adaptive flow regulation and water control completion parameters in acidic gas reservoirs, optimizes the combination of adaptive flow regulation and water control screen parameters, predicts the flow regulation and water control completion effect in acidic gas reservoirs, enhances the effectiveness of flow regulation and water control, achieves water control and gas stabilization in acidic gas reservoirs, and ultimately improves the recovery rate of acidic gas reservoirs.

[0008] This invention is achieved through the following technical solution:

[0009] In a first aspect, the present invention provides a numerical simulation method for well completion in acidic gas reservoirs with flow regulation and water control. The method considers the influence of sulfur deposition on water control in acidic gas reservoirs, simulates the development characteristics of acidic gas reservoirs, optimizes the parameters of adaptive flow regulation and water control screen pipes in acidic gas reservoirs, thereby enhancing the development effect of well completion in acidic gas reservoirs with flow regulation and water control, realizing water control and gas stabilization in acidic gas reservoirs, and improving the recovery rate of acidic gas reservoirs.

[0010] A further improvement of the present invention is that the method includes:

[0011] Step 1: Collect geological and production parameters of acidic gas reservoirs;

[0012] Step 2: Establish a geological model of the target block of the acidic gas reservoir;

[0013] Step 3: Establish a single-well geological model for acidic gas wells;

[0014] Step 4: Determine the time-varying skin coefficient of sulfur deposition in acidic gas reservoirs;

[0015] Step 5: Determine the specifications of the adaptive flow control and water regulation screen for acidic gas wells;

[0016] Step Six: Adaptive Flow Regulation and Water Control Completion Design for Acidic Gas Wells;

[0017] Step 7: Coupled numerical simulation of wellbore and reservoir for flow regulation and water control in acidic gas reservoirs;

[0018] Step 8: Obtain the optimal adaptive flow control and water control screen parameters for acidic gas reservoirs.

[0019] A further improvement of the present invention is that the geological and production parameters collected in step one include: reservoir characteristic parameters, well logging interpretation parameters, fluid high-pressure physical property parameters, wellhead parameters, wellbore trajectory parameters, wellbore structural parameters, and production dynamic parameters.

[0020] A further improvement of the present invention is that the operation of step two includes: using reservoir characteristic parameters, logging interpretation parameters, wellhead parameters, and wellbore trajectory parameters to establish a geological model of the target block of the acidic gas reservoir, obtaining the distribution law of porosity, permeability and saturation attributes of the target block, and verifying the reserves of the geological model.

[0021] A further improvement of the present invention is that the operation of step three includes: on the basis of the geological model of the target block of the acidic gas reservoir, extracting and establishing a geological model of the acidic gas well within the control range of the target well.

[0022] A further improvement of the present invention is that the operation of step four includes:

[0023] The undetermined coefficients k, a, and B in the following formula are fitted using measured sulfur solubility data:

[0024] c s =ρ k exp(a / T+B)

[0025] in,

[0026] In the formula, c s ρ is the solubility of elemental sulfur in acidic gases, p is the density of the acidic gas, and γ is the pressure. g Z is the relative density of the acidic gas; T is the deviation coefficient of the acidic gas; and T is the temperature of the acidic gas.

[0027] The time-varying skin coefficient of sulfur deposition is calculated using the following formula:

[0028]

[0029] in,

[0030]

[0031]

[0032]

[0033] S s Let A be the sedimentary sulfur saturation, t be time, q be well production, and B be... g Here, r is the gas phase volume coefficient, r is the radial distance from the wellbore, h is the formation thickness, and μ is the gas phase volume coefficient. g Let p be the gas phase viscosity, k0 be the permeability under the original conditions of the gas reservoir, and p be the permeability. i φ represents the original formation pressure of the gas reservoir, m is the stress sensitivity index, φ is the porosity, and Sw i σ is the initial water saturation, β is the non-Darcy flow coefficient, and s d r is the time-varying skin coefficient of sulfur deposition. d Let r be the radius of the pollution zone. w Where is the well radius.

[0034] A further improvement of the present invention is that the operation of step five includes:

[0035] The diameter of the adaptive flow control screen pipe is selected based on the well structure parameters;

[0036] The material and coupling type of the adaptive flow control screen tube are determined based on the hydrogen sulfide and carbon dioxide content.

[0037] The diameter of the adaptive flow control screen tube is larger than that of a conventional screen tube of the same specification.

[0038] The adaptive water control screen needs to be used in conjunction with an oil-expanding packer.

[0039] A further improvement of the present invention is that the operation of step six includes:

[0040] The insertion length of the adaptive flow control screen in acidic gas wells is designed based on wellbore trajectory parameters;

[0041] Based on the well logging interpretation parameters, design the number of adaptive flow control segments, determine the number of adaptive flow control screens and packers, and determine the insertion depth of the packers.

[0042] A further improvement of the present invention is that the operation of step seven includes:

[0043] Using geological and production parameters of acidic gas reservoirs, a multi-section well model was used to simulate the wellbore of an acidic gas well with adaptive flow control screen and packer.

[0044] The characteristics of the adaptive flow control screen tube are simulated using the following formula:

[0045]

[0046] In the formula, ΔP is the pressure drop of the adaptive flow control screen tube, and a AICD To adapt the water control intensity of the flow regulation and water control screen, ρ mix For the density of the inflowing fluid, μ mix Let y be the viscosity of the inflow fluid, Q be the fluid flow rate of the adaptive flow control screen, x be the flow rate index, and y be the viscosity index.

[0047] The time-varying skin coefficient of the sulfur deposition was added to the near-wellbore zone, and coupled numerical simulation was performed using a black oil model.

[0048] The operations in step eight include:

[0049] Pressure or production rate is selected as the control condition, and the reduction in cumulative water production during the prediction period is used as the optimization objective. The parameter combination of the adaptive flow control screen tube is optimized using orthogonal experimental numerical simulation: a AICD The optimal adaptive flow control and water control screen parameters for acidic gas reservoirs are obtained by using x, y, and x.

[0050] A second aspect of the present invention provides a numerical simulation system for well completion in acidic gas reservoirs involving flow regulation and water control, the system comprising:

[0051] The acquisition unit is used to collect geological and production parameters of acidic gas reservoirs;

[0052] The target block geological model establishment unit is connected to the acquisition unit and is used to establish a geological model of the target block of the acidic gas reservoir.

[0053] A single-well geological model establishment unit is connected to the target block geological model establishment unit and is used to establish a single-well geological model for acidic gas wells.

[0054] The coefficient determination unit, connected to the single-well geological model establishment unit, is used to determine the time-varying skin coefficient of sulfur deposition in acidic gas reservoirs;

[0055] A screen pipe specification determination unit, connected to the coefficient determination unit, is used to determine the screen pipe specifications for adaptive flow regulation and water control in acidic gas wells.

[0056] The well completion design unit, connected to the screen pipe specification determination unit, is used for adaptive flow regulation and water control well completion design of acid gas wells;

[0057] The coupled numerical simulation unit is connected to the well completion design unit and is used for coupled numerical simulation of the wellbore reservoir for flow regulation and water control in acidic gas reservoirs.

[0058] An optimization unit, connected to the coupled numerical simulation unit, is used to obtain the optimal parameters for the adaptive flow control and water management screen pipe in the acidic gas reservoir.

[0059] Compared with the prior art, the beneficial effects of the present invention are: the present invention enhances the development effect of flow regulation and water control well completion in acidic gas reservoirs, realizes water control and gas stabilization in acidic gas reservoirs, improves the recovery rate of acidic gas reservoirs, and provides guidance for the design and application of flow regulation and water control well completion in acidic gas reservoirs. Attached Figure Description

[0060] Figure 1 This is a flowchart of the method of the present invention;

[0061] Figure 2 A single-well geological model of P1H well in the Puguang acidic gas field;

[0062] Figure 3 Comparison of cumulative water production of P1H well in Puguang acidic gas field under adaptive flow control and water control completion conditions and perforation completion conditions;

[0063] Figure 4-1 This is a near-wellbore water saturation profile of the P1H well in the Puguang acidic gas field under perforated completion conditions.

[0064] Figure 4-2Water saturation profile of the near-wellbore zone of well P1H in the Puguang acidic gas field under adaptive flow regulation and water control completion conditions;

[0065] Figure 5 A schematic diagram of the system composition of this invention. Detailed Implementation

[0066] The present invention will now be described in further detail with reference to the accompanying drawings:

[0067] Considering the impact of sulfur deposition on water control in acidic gas reservoirs, this invention proposes a numerical simulation method for flow regulation and water control completion in acidic gas reservoirs. This method can simulate the development characteristics of acidic gas reservoirs, optimize the adaptive flow regulation and water control screen parameters, enhance the development effect of flow regulation and water control completion in acidic gas reservoirs, achieve water control and gas stabilization in acidic gas reservoirs, improve the recovery rate of acidic gas reservoirs, and provide guidance for the design and application of flow regulation and water control completion in acidic gas reservoirs.

[0068] like Figure 1 As shown, the method of the present invention includes:

[0069] Step 1: Collect geological and production parameters of the acidic gas reservoir. These parameters include: reservoir characteristic parameters, well logging interpretation parameters, high-pressure fluid properties, wellhead parameters, wellbore trajectory parameters, wellbore structural parameters, and production dynamic parameters.

[0070] Step 2: Establish a geological model of the target block of the acidic gas reservoir. Using reservoir characteristic parameters, well logging interpretation parameters, wellhead parameters, and wellbore trajectory parameters, establish a geological model of the target block of the acidic gas reservoir, obtain the distribution patterns of porosity, permeability, and saturation attributes of the target block, and verify the reserves of the geological model.

[0071] Step 3: Establish single-well geological models for acidic gas wells. Based on the geological model of the target block of the acidic gas reservoir, extract and establish single-well geological models within the control range of the target well.

[0072] Step 4: Determine the time-varying skin coefficient of sulfur deposition in acidic gas reservoirs. Using high-pressure physical property measured sulfur solubility data (measured using existing technology, such as using a PVT device to conduct high-pressure fluid physical property experiments to obtain elemental sulfur solubility data in acidic gases under different temperature and pressure conditions), fit the undetermined coefficients k, a, and B in equation (1) to calculate the solubility of elemental sulfur in acidic gases. Specifically, first use the high-pressure physical property measured sulfur solubility data to fit and obtain three undetermined coefficients k, a, and B, and calculate the density of acidic gases according to the known temperature and pressure data:

[0073]

[0074] In the formula, γ gZ is the relative density of the acidic gas, dimensionless; Z is the deviation coefficient of the acidic gas, dimensionless, which can be determined using the Hall-Yarbough method. Finally, the solubility of elemental sulfur in the acidic gas can be obtained according to equation (1);

[0075] Then, the sulfur saturation of the deposit is calculated using equations (2) to (4); the time-varying skin coefficient of the sulfur deposit is calculated using equation (5).

[0076] c s =ρ k exp(a / T+B) (1)

[0077]

[0078] in,

[0079]

[0080]

[0081]

[0082] Among them, c s The solubility of elemental sulfur in acidic gases, in g / m³. 3 ρ is the density of the acidic gas, kg / m³ 3 T is the temperature of the acidic gas, in K; k, a, and B are undetermined coefficients, dimensionless; S s For the deposition sulfur saturation, m 3 / m 3 A is a constant coefficient, dimensionless; t is time, y is the well production rate, and q is the well output. 4 m 3 / d;B g m is the gas phase volume coefficient. 3 / m 3 ; r is the radial distance from the wellbore, in meters; h is the formation thickness, in meters; μ g k is the gas phase viscosity, mPa·s; k0 is the permeability under the original conditions of the gas reservoir, mD; p i ρ is the original formation pressure of the gas reservoir, MPa; p is the pressure, MPa; m is the stress sensitivity index, dimensionless; φ is the porosity, dimensionless; Sw i The initial water saturation is dimensionless; β is the non-Darcy flow coefficient, m -1 β can be calculated by the following formula: In the formula, k is the permeability, mD, s d r is the time-varying skin coefficient of sulfur deposition, dimensionless; d r is the radius of the pollution zone, in meters (m). w Let be the well radius, in meters. Among these parameters... All other parameters were collected from step one.

[0083] The time-varying skin coefficients of sulfur deposition calculated by formulas (1) to (5) will be used in step seven.

[0084] Step 5: Determine the specifications of the adaptive flow control screen for acidic gas wells. Select the diameter of the adaptive flow control screen based on the wellbore structural parameters. Determine the tubing material and thread type of the adaptive flow control screen based on the hydrogen sulfide and carbon dioxide content (these two contents are obtained from the high-pressure fluid properties collected in Step 1).

[0085] The methods for determining the tubing material and coupling type of the adaptive flow control screen are existing technologies and will not be elaborated here. However, this invention considers the following factors when selecting the diameter of the adaptive flow control screen:

[0086] 1. The diameter of the adaptive flow control screen tube is different from that of the conventional screen tube; the diameter of the adaptive flow control screen tube is larger than that of the conventional screen tube of the same specification.

[0087] 2. Adaptive water control screens need to be used in conjunction with oil-expanding packers, while conventional screens do not require the use of oil-expanding packers.

[0088] Step Six: Adaptive Flow Control and Water Management Completion Design for Acid Gas Wells. Based on wellbore trajectory parameters, design the insertion length of the adaptive flow control and water management screen in the acid gas well. Based on well logging interpretation parameters, design the number of adaptive flow control and water management segments, determine the number of adaptive flow control and water management screens and packers, and determine the insertion depth of the packers.

[0089] Specifically, this invention determines the total length of the adaptive flow control screen based on the length of the wellbore trajectory through the target formation. Then, based on the permeability data along the wellbore trajectory obtained from well logging interpretation, and referring to the wellbore diameter and water saturation data obtained from well logging interpretation, the number of adaptive flow control segments is designed (mainly based on the permeability along the wellbore trajectory and referring to the water saturation data, the wellbore is divided into several high-permeability, high-water-cut segments and low-permeability, low-water-cut segments, with a total number of segments not exceeding four; then, referring to the wellbore diameter data, the location where the wellbore diameter significantly decreases between each segment is used as the segmentation point, thus designing the number of adaptive water control segments). Packers are then installed at the segmentation points between each segment, thus determining the packer installation depth.

[0090] Wherein, the number of packers = the number of segments; an adaptive flow control screen is installed in each segment, and the number of adaptive flow control screens in each segment = [the length of each segment / the length of the adaptive flow control screen], where [] is the rounding function.

[0091] Step 7: Coupled numerical simulation of flow regulation and water control wellbore-reservoir in acidic gas reservoir. Using the geological and production parameters of the acidic gas reservoir, a multi-section well model is used to simulate the wellbore of the acidic gas well with adaptive flow regulation and water control screen and packer. The characteristics of the adaptive flow regulation and water control screen are simulated by equation (6), and the time-varying skin coefficient of sulfur deposition calculated by equation (5) is added in the near-wellbore zone. Coupled numerical simulation is performed using a black oil model.

[0092]

[0093] In the formula, ΔP is the pressure drop of the adaptive flow control screen tube, in MPa; a AICD To adapt the water control intensity of the flow regulation and water control screen, 10 -1 MPa / [(kg·m -3 (m) 3 ·d) x ];ρ mix The density of the inflowing fluid is kg / m³ 3 μ mix The viscosity of the inflow fluid is denoted as ρ, mPa·s; Q is the fluid flow rate in the adaptive flow control screen tube, m³ / s. 3 / d; x is the flow rate index, dimensionless; y is the viscosity index, dimensionless.

[0094] In step six, the number of adaptive flow control screens was determined, but the characteristics of each adaptive flow control screen were not determined. In step seven, the characteristics of each adaptive flow control screen were further determined. The characteristics of the adaptive flow control screens in each adaptive flow control segment are the same, while the characteristics of the adaptive flow control screens in different adaptive flow control segments are different. The characteristics of each adaptive flow control screen are calculated using equation (6).

[0095] The time-varying skin coefficient of sulfur deposition at each simulation time step is calculated according to equation (5). Then, at each simulation time step in the numerical simulation, the time-varying skin coefficient of sulfur deposition calculated according to equation (5) is added to the wellbore skin coefficient option in the numerical simulation software.

[0096] Step 8: Optimization of three parameters for adaptive flow regulation and water control screen pipes in acidic gas reservoirs. Selecting pressure or production as the control condition (selecting pressure as the control condition means adopting a constant pressure production mode; selecting production as the control condition means adopting a constant production mode), and using the reduction in cumulative water production during the predicted period as the optimization objective, the orthogonal experimental numerical simulation method is used to optimize the 'a' parameter of the adaptive flow regulation and water control screen pipes. AICD The combination of x and y parameters.

[0097] Specifically, the daily water production at each simulation time step during the prediction period can be obtained using numerical simulation. The cumulative water production during the prediction period is obtained by summing up the daily water production at all simulation time steps. The benchmark for comparing the reduction in the cumulative water production during the prediction period is the cumulative water production during the prediction period simulated under the same control conditions and prediction period as adaptive flow control and water control well completion.

[0098] The ultimate goal of this invention is to obtain the optimal a under a specified pressure or output. AICD The combinations of parameters x and y are as follows:

[0099] Given a combination of parameters (a AICD The adaptive flow control screen characteristics (x, y) are obtained. Then, these characteristics and the time-varying skin coefficient of sulfur deposition are input into the black oil model for coupled numerical simulation to obtain a cumulative water production during the prediction period. The cumulative water production during the prediction period simulated under the same perforated completion method is then calculated. The difference between the two is divided by the cumulative water production during the prediction period simulated under the perforated completion method to obtain the reduction rate. Finally, the parameter combination corresponding to the largest reduction rate is the optimal combination.

[0100] The embodiments of the method of the present invention are as follows:

[0101] Example 1

[0102] Taking the Puguang acidic gas field as an example, the numerical simulation design method for well completion of acidic gas reservoir flow regulation and water control according to the present invention specifically includes the following steps:

[0103] Step 1: Collect geological and production parameters of the acidic gas reservoir. These parameters include: reservoir characteristic parameters, well logging interpretation parameters, high-pressure fluid properties, wellhead parameters, wellbore trajectory parameters, wellbore structure parameters, and production dynamic parameters.

[0104] Step 2: Establish a geological model of the target block of the acidic gas reservoir. Using reservoir characteristic parameters, well logging interpretation parameters, wellhead parameters, and wellbore trajectory parameters, establish a geological model of the target block of the acidic gas reservoir, obtain the distribution patterns of porosity, permeability, and saturation attributes of the target block, and verify the reserves of the geological model.

[0105] Using the main block of the Puguang acidic gas field as the target block, a geological model of the target block was established using Petrel geological modeling software and the Gaussian random function simulation method. The porosity, permeability, and saturation distribution patterns of the Feixianguan Formation and Changxing Formation in the target block were obtained. The geological model yielded a reserve of 16.39 × 10⁻⁶. 8 sm 3 The storage capacity obtained by applying the volumetric method formula is 16.8 × 10⁻⁶. 8 sm 3The geological model was used to verify its reserves. These were all achieved using existing technologies, and will not be elaborated upon here.

[0106] Step 3: Establish single-well geological models for acidic gas wells. Based on the geological model of the target block of the acidic gas reservoir, extract and establish single-well geological models within the control range of the target well.

[0107] Based on the geological model of the main block of the Puguang acidic gas field, and considering the flow boundary, a single-well geological model of the P1H well was extracted and established, such as... Figure 2 As shown. These are all implemented using existing technologies, and will not be elaborated further here.

[0108] Step 4: Determine the time-varying skin coefficient of sulfur deposition in acidic gas reservoirs. Using high-pressure physical property measured sulfur solubility data, fit the undetermined coefficients k, a, and B in equation (1) to calculate the solubility of elemental sulfur in acidic gas; use equations (2) to (4) to calculate the sulfur saturation of deposition; use equation (5) to calculate the time-varying skin coefficient of sulfur deposition.

[0109] c s =ρ k exp(a / T+B) (1)

[0110]

[0111] in,

[0112]

[0113]

[0114]

[0115] In the above formula, c s The solubility of elemental sulfur in acidic gases, in g / m³. 3 ρ is the density of the acidic gas, kg / m³ 3 T is the temperature of the acidic gas, in K; k, a, and B are undetermined coefficients, dimensionless; S s For the deposition sulfur saturation, m 3 / m 3 A is a constant coefficient, dimensionless; t is time, y is the well production rate, and q is the well output. 4 m 3 / d;B g m is the gas phase volume coefficient. 3 / m 3 ; r is the radial distance from the wellbore, in meters; h is the formation thickness, in meters; μ g k is the gas phase viscosity, mPa·s; k0 is the permeability under the original conditions of the gas reservoir, mD; p iρ is the original formation pressure of the gas reservoir, MPa; p is the pressure, MPa; m is the stress sensitivity index, dimensionless; φ is the porosity, dimensionless; Sw i The initial water saturation is dimensionless; β is the non-Darcy flow coefficient, m -1 ;s d r is the time-varying skin coefficient of sulfur deposition, dimensionless; d r is the radius of the pollution zone, in meters (m). w Let be the well radius, in meters (m).

[0116] Using the measured sulfur solubility data of high-pressure physical properties of well P1H, the undetermined coefficients k, a and B in equation (1) were fitted to be 3.14, -5807 and -2.85, respectively; the deposition sulfur saturation of well P1H was calculated using equations (2) to (4); the time-varying skin coefficient of sulfur deposition in well P1H was calculated using equation (5) as shown in Table 1.

[0117]

[0118]

[0119] Table 1

[0120] Step 5: Determine the specifications of the adaptive flow control and water control screen for acidic gas wells. Select the diameter of the adaptive flow control and water control screen based on the wellbore structural parameters, and determine the tubing material and thread type based on the hydrogen sulfide and carbon dioxide content.

[0121] Based on the wellbore structural parameters of P1H well, the diameter of the adaptive flow control screen is selected as 5-1 / 2". Based on the hydrogen sulfide and carbon dioxide content, the material of the adaptive flow control screen is determined to be 35CroMo, and the thread type is VAM TOP airtight thread. Detection and prevention of hydrogen sulfide in P1H well should be carried out.

[0122] Step Six: Adaptive Flow Control and Water Management Completion Design for Acid Gas Wells. Based on wellbore trajectory parameters, design the insertion length of the adaptive flow control and water management screen in the acid gas well. Based on well logging interpretation parameters, design the number of adaptive flow control and water management segments, determine the number of adaptive flow control and water management screens and packers, and determine the insertion depth of the packers.

[0123] Based on the wellbore trajectory parameters of P1H well, the length of the adaptive flow control screen pipe is designed to be 525m. Based on the logging interpretation parameters of permeability, well diameter, and water saturation, the adaptive flow control water segment is designed to be 4 segments. 4 oil-expanding packers are installed, along with 48 adaptive flow control screen pipes. The installation depths of the 4 oil-expanding packers are 5860m, ​​6000m, 6120m, and 6250m, respectively.

[0124] Step 7: Coupled numerical simulation of flow regulation and water control wellbore-reservoir in acidic gas reservoir. Using the geological and production parameters of the acidic gas reservoir, a multi-section well model is used to simulate the wellbore of the acidic gas well with adaptive flow regulation and water control screen and packer. The characteristics of the adaptive flow regulation and water control screen are simulated by equation (6), and the time-varying skin coefficient of sulfur deposition is added in the near-wellbore zone. Coupled numerical simulation is performed using a black oil model.

[0125]

[0126] In the formula, ΔP is the pressure drop of the adaptive flow control screen tube, in MPa; a AICD To adapt the water control intensity of the flow regulation and water control screen, 10 -1 MPa / [(kg·m -3 (m) 3 ·d) x ];ρ mix The density of the inflowing fluid is kg / m³ 3 μ mix The viscosity of the inflow fluid is denoted as ρ, mPa·s; Q is the fluid flow rate in the adaptive flow control screen tube, m³ / s. 3 / d; x is the flow rate index, dimensionless; y is the viscosity index, dimensionless.

[0127] Using Eclipse numerical simulation software, and taking into account the geological parameters of the Puguang acidic gas reservoir and the production parameters of the P1H well, a coupled numerical simulation of the P1H wellbore-reservoir was carried out. A multi-segment well model was used to simulate the P1H wellbore with adaptive flow control screen and packer installed. The wellbore was divided into 17 segments. The characteristics of the adaptive flow control screen were simulated by equation (6). The time-varying skin coefficient of sulfur deposition as shown in Table 1 was added in the near-wellbore zone. A black oil model was used for coupled numerical simulation.

[0128] Step 8: Optimization of three parameters for adaptive flow regulation and water control screen pipes in acidic gas reservoirs. Pressure or production is selected as the control condition, and the reduction in cumulative water production during the predicted period is used as the optimization objective. The parameters 'a' of the adaptive flow regulation and water control screen pipes are optimized using orthogonal experimental numerical simulation. AICD The combination of x and y parameters.

[0129] The P1H well was selected with gas production as the control condition, and the set gas production rate was 19 × 10⁻⁶. 4 m 3 / d, comparing the cumulative water production of perforated completions and adaptive flow control completions, and using the reduction in cumulative water production over a 10-year prediction period as the optimization objective, a three-factor, four-level orthogonal experimental design was conducted, as shown in Table 2. Numerical simulation methods were used to optimize the a of the adaptive flow control screen. AICD The combination of parameters x and y is 0.0012 × 10 -1 MPa / [(kg·m -3 (m) 3·d) x ], 1, 1.5. Optimal a AICD Comparison of cumulative water production under the conditions of combined parameters x, y, etc. Figure 3 As shown.

[0130]

[0131] Table 2

[0132] After applying the numerical simulation design method for water control and flow regulation completion in acidic gas reservoirs, the P1H well showed a cumulative water production reduction of approximately 18% compared to perforated completion, which delayed bottom water coning. Simultaneously, compared with... Figure 4-1 and Figure 4-2 It can be seen that the water saturation in the near-well zone is generally reduced, indicating that the optimized adaptive flow regulation and water control screen has a certain water control effect, which can suppress the rise in water content and achieve water control and stable gas production in acidic gas reservoirs.

[0133] Figure 3 This study compares the cumulative water production of the P1H well in the Puguang acidic gas field under adaptive flow control and water-controlled completion conditions with those under perforated completion conditions. Compared to perforated completion, the predicted cumulative water production at the end of the projected period is reduced by approximately 18% under adaptive flow control and water-controlled completion conditions.

[0134] This invention also provides a numerical simulation system for well completion in acidic gas reservoirs with flow regulation and water control, such as... Figure 5 As shown, an embodiment of the system is as follows:

[0135]

Example 2

[0136] The system includes:

[0137] Acquisition unit 10 is used to collect geological parameters and production parameters of acidic gas reservoirs;

[0138] The target block geological model establishment unit 20 is connected to the acquisition unit 10 and is used to establish a geological model of the target block of the acid gas reservoir.

[0139] The single-well geological model establishment unit 30 is connected to the target block geological model establishment unit 20 and is used to establish a single-well geological model for acidic gas wells.

[0140] The coefficient determination unit 40 is connected to the single-well geological model establishment unit 30 and is used to determine the time-varying skin coefficient of sulfur deposition in acidic gas reservoirs.

[0141] The screen pipe specification determination unit 50 is connected to the coefficient determination unit 40 and is used to determine the screen pipe specification for adaptive flow regulation and water control in acidic gas wells.

[0142] The well completion design unit 60 is connected to the screen pipe specification determination unit 50 and is used for adaptive flow regulation and water control well completion design of acid gas wells.

[0143] The coupled numerical simulation unit 70 is connected to the well completion design unit 60 and is used for coupled numerical simulation of the wellbore reservoir for flow regulation and water control in acidic gas reservoirs.

[0144] The optimization unit 80 is connected to the coupled numerical simulation unit 70 and is used to obtain the optimal parameters of the adaptive flow control and water control screen pipe for acidic gas reservoirs.

[0145] Acidic gas reservoirs are widely distributed worldwide, with over 400 commercially viable reservoirs discovered globally. Developing acidic water-bearing gas reservoirs requires robust measures to prevent corrosion and blockage of acidic gases, while simultaneously implementing water control and gas stabilization. However, currently, there is no specific well completion design method for water control and flow regulation in acidic gas reservoirs, failing to guide optimized design and hindering the effective application of this technology. This invention considers the impact of sulfur deposition on water control and flow regulation in acidic gas reservoirs, simulating the development characteristics of such reservoirs, optimizing adaptive water control and flow regulation screen parameters, enhancing the effectiveness of well completions, achieving water control and gas stabilization, improving recovery rates, and providing guidance for well completion design and application in acidic gas reservoirs.

[0146] Finally, it should be noted that the above technical solution is only one embodiment of the present invention. For those skilled in the art, based on the application methods and principles disclosed in the present invention, it is easy to make various types of improvements or modifications, and not limited to the methods described in the above specific embodiments of the present invention. Therefore, the methods described above are only preferred and have no limiting significance.

Claims

1. A numerical simulation method for well completion in an acidic gas reservoir with flow regulation and water control, characterized in that: The method considers the impact of sulfur deposition on water control in acidic gas reservoirs, simulates the development characteristics of acidic gas reservoirs, optimizes the parameters of adaptive flow regulation and water control screen pipes for acidic gas reservoirs, thereby enhancing the well completion and development effect of flow regulation and water control in acidic gas reservoirs, realizing water control and gas stabilization in acidic gas reservoirs, and improving the recovery rate of acidic gas reservoirs. The method includes: Step 1: Collect geological and production parameters of acidic gas reservoirs; Step 2: Establish a geological model of the target block of the acidic gas reservoir; Step 3: Establish a single-well geological model for acidic gas wells; Step 4: Determine the time-varying skin coefficient of sulfur deposition in acidic gas reservoirs; Step 5: Determine the specifications of the adaptive flow control and water regulation screen for acidic gas wells; Step Six: Adaptive Flow Regulation and Water Control Completion Design for Acidic Gas Wells; Step 7: Coupled numerical simulation of flow regulation and water control wellbore reservoir in acidic gas reservoirs; add the time-varying skin coefficient of the sulfur deposition in the near-wellbore zone, and use the black oil model for coupled numerical simulation; Step 8: Obtain the optimal adaptive flow control and water control screen parameters for acidic gas reservoirs.

2. The numerical simulation method for well completion in acidic gas reservoirs with flow regulation and water control according to claim 1, characterized in that: The geological and production parameters collected in step one include: reservoir characteristic parameters, well logging interpretation parameters, high-pressure fluid properties, wellhead parameters, wellbore trajectory parameters, wellbore structure parameters, and production dynamic parameters.

3. The numerical simulation method for well completion in acidic gas reservoirs with flow regulation and water control according to claim 1, characterized in that: The second step includes: using reservoir characteristic parameters, well logging interpretation parameters, wellhead parameters, and wellbore trajectory parameters to establish a geological model of the target block of the acidic gas reservoir, obtain the distribution law of porosity, permeability, and saturation attributes of the target block, and verify the reserves of the geological model.

4. The numerical simulation method for well completion in acidic gas reservoirs with flow regulation and water control according to claim 1, characterized in that: The operation of step three includes: on the basis of the geological model of the target block of the acidic gas reservoir, extracting and establishing a single-well geological model of the acidic gas well within the control range of the target well.

5. The numerical simulation method for well completion in acidic gas reservoirs with flow regulation and water control according to claim 1, characterized in that: The operations in step four include: The undetermined coefficients in the following formula are fitted using measured sulfur solubility data. k , a , B : in, In the formula, This represents the solubility of elemental sulfur in acidic gases. The density of the acidic gas. For pressure, The relative density of the acidic gas; This is the deviation coefficient for acidic gases; The temperature of the acidic gas; The time-varying skin coefficient of sulfur deposition is calculated using the following formula: in, For the deposition of sulfur saturation, The constant coefficient, For time, For well production, The gas phase volume coefficient, The radial distance from the wellbore. For the thickness of the strata, The viscosity is the gas phase viscosity. The permeability is the value of the gas reservoir under its original conditions. This represents the original formation pressure of the gas reservoir. The stress sensitivity index, Porosity This represents the original water saturation level. For non-Darcy flow coefficients, The time-varying skin coefficient for sulfur deposition. The radius of the pollution zone, Where is the well radius.

6. The numerical simulation method for well completion in acidic gas reservoirs with flow regulation and water control according to claim 1, characterized in that: The operations in step five include: The diameter of the adaptive flow control screen pipe is selected based on the well structure parameters; The material and coupling type of the adaptive flow control screen tube are determined based on the hydrogen sulfide and carbon dioxide content. The diameter of the adaptive flow control screen tube is larger than that of a conventional screen tube of the same specification. The adaptive flow control screen tube needs to be used in conjunction with an oil-expanding packer.

7. The numerical simulation method for well completion in acidic gas reservoirs with flow regulation and water control according to claim 1, characterized in that: The operations in step six include: The insertion length of the adaptive flow control screen in acidic gas wells is designed based on wellbore trajectory parameters; Based on the well logging interpretation parameters, design the number of adaptive flow control segments, determine the number of adaptive flow control screens and packers, and determine the insertion depth of the packers.

8. The numerical simulation method for well completion in acidic gas reservoirs with flow regulation and water control according to claim 1, characterized in that: The operations in step seven include: Using geological and production parameters of acidic gas reservoirs, a multi-section well model was used to simulate the wellbore of an acidic gas well with adaptive flow control screen and packer. The characteristics of the adaptive flow control screen tube are simulated using the following formula: In the formula, To adaptively adjust the pressure drop of the water control screen tube, To adapt the water control intensity of the flow regulation and water control screen, For the density of the inflowing fluid, The viscosity of the inflowing fluid. To adaptively regulate the fluid flow rate of the water control screen, For traffic index, This is the viscosity index.

9. The numerical simulation method for well completion in acidic gas reservoirs with flow regulation and water control according to claim 1, characterized in that: The operations in step eight include: Pressure or production rate was selected as the control condition, and the reduction in cumulative water production during the prediction period was used as the optimization objective. The parameter combination of the adaptive flow control screen tube was optimized using orthogonal experimental numerical simulation. , , The optimal adaptive flow control and water control screen parameters for acidic gas reservoirs were obtained.

10. A numerical simulation system for well completion in an acidic gas reservoir with flow regulation and water control, based on the method described in any one of claims 1-9, characterized in that: The system includes: The acquisition unit is used to collect geological and production parameters of acidic gas reservoirs; The target block geological model establishment unit is connected to the acquisition unit and is used to establish a geological model of the target block of the acidic gas reservoir. A single-well geological model establishment unit is connected to the target block geological model establishment unit and is used to establish a single-well geological model for acidic gas wells. The coefficient determination unit, connected to the single-well geological model establishment unit, is used to determine the time-varying skin coefficient of sulfur deposition in acidic gas reservoirs; A screen pipe specification determination unit, connected to the coefficient determination unit, is used to determine the screen pipe specifications for adaptive flow regulation and water control in acidic gas wells. The well completion design unit, connected to the screen pipe specification determination unit, is used for adaptive flow regulation and water control well completion design of acid gas wells; The coupled numerical simulation unit is connected to the well completion design unit and is used for coupled numerical simulation of the wellbore reservoir for flow regulation and water control in acidic gas reservoirs. An optimization unit, connected to the coupled numerical simulation unit, is used to obtain the optimal parameters for the adaptive flow control and water management screen pipe in the acidic gas reservoir.

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