A layered control valve oil well production prediction method considering annular storage effect

Abstract

The present application belongs to the field of oil and gas field development, and particularly relates to a layered control valve oil well production prediction method considering annular storage effect; the present application considers the pressure change and fluid flow characteristics in the annulus, firstly, the fluid production indexes of each layer are fitted before the layered control valve is lowered, the annulus pressure under the influence of the layered control valve changing the opening degree is calculated through iterative calculation after the layered control valve is lowered, and the annulus inflow and wellbore inflow are calculated by using the calculated annulus pressure, finally, the wellbore inflow calculated is fitted with the actual oil well production to obtain the flow coefficient of each layer, the production prediction of the fixed bottom hole flowing pressure is carried out through the flow coefficient of each layer, and the influence of the annular storage effect on the production prediction is solved. The present application not only improves the accuracy and stability of the production prediction, but also has wide applicability and popularization value, and provides strong support for efficient development of multi-layer reservoirs.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of oil and gas field development, and particularly relates to a layered control valve oil well production prediction method considering annular storage effect. BACKGROUND

[0002] In the development process of multi-layer oil wells, accurate prediction of oil well production is of great significance for optimizing production strategy, improving recovery efficiency and reducing operating costs. Traditional oil well production prediction methods are mainly based on empirical formula or numerical simulation, but these methods often ignore the influence of annular storage effect on production, resulting in large deviation between predicted results and actual situation. Annular storage effect refers to the influence of fluid storage and release in the annulus on production due to the change of layered control valve opening during the production process of multi-layer oil wells with layered control valve. After a period of layer closing, the pressure in the target layer is increased, and then the layer is opened, which leads to a large increase in initial production. This phenomenon is represented as a sharp point in the fitting process. This effect will affect the transient pressure response and production change of the oil well, and further affect the development effect of the whole reservoir. Although the existing technologies such as empirical formula method and numerical simulation method can predict the production to some extent, the prediction accuracy and reliability are limited due to the lack of consideration of annular storage effect.

[0003] In order to solve the above problems, the present application provides a layered control valve oil well production prediction method considering annular storage effect. This method introduces an annular storage effect model to consider the pressure change and fluid flow characteristics in the annulus, and combines the dynamic adjustment strategy of layered control valve opening to realize high-precision prediction of oil well production. The present application not only improves the accuracy and stability of production prediction, but also has wide applicability and promotional value, providing strong support for efficient development of multi-layer reservoirs. SUMMARY

[0004] The purpose of the present application is to solve the influence of annular storage effect on production prediction, and a layered control valve oil well production prediction method considering annular storage effect is proposed. First, the layer liquid production index is fitted before the layered control valve is lowered, and then the annulus pressure under the influence of the change of layered control valve opening is calculated by iterative calculation. The calculated annulus inflow and wellbore inflow are calculated using the calculated annulus pressure. Finally, the calculated wellbore inflow and actual oil well production are fitted to obtain the flow coefficient of each layer. The flow coefficient of each layer can be used for production prediction with fixed bottom hole flowing pressure, solving the influence of annular storage effect on production prediction.

[0005] To achieve the above purpose, the present application provides a layered control valve oil well production prediction method considering annular storage effect, which comprises the following steps:

[0006] First, first collect the static parameters of the target well, the dynamic parameters before the layered control valve is lowered, and the dynamic parameters after the layered control valve is lowered;

[0007] Second, before the layered control valve is lowered, the permeability of the i th layer, the effective thickness of the i th layer, the fluid viscosity of the i th layer, the oil volume factor of the i th layer, the drainage radius, and the wellbore radius parameters are substituted into the liquid production index calculation formula to calculate the initial liquid production index of the i th layer. One day is taken as a cycle in the production data, the formation pressure of the i th layer, the bottom hole flowing pressure of the i th layer, and the calculated initial liquid production index of the i th layer are used to iteratively calculate the production of the i th layer through the oil well flow productivity equation, and the production of each layer is added to obtain the production of an oil well; the liquid production index of the i th layer is continuously adjusted, and the iteratively calculated oil well production is fitted with the actual oil well production; after successful fitting, the actual liquid production index of the i th layer is obtained;

[0008] Third, the oil well with the layered control valve lowered is divided into two cases of unchanged valve opening and changed valve opening; when the layered control valve does not change the valve opening of the i th layer, the reservoir to annulus productivity equation and the control valve productivity equation are solved, the formation pressure of the i th layer, the flow coefficient of the i th layer, the control valve opening of the i th layer, the layered control valve flow area, the bottom hole flowing pressure of the i th layer, the fluid density of the i th layer, and the fitted liquid production index of the i th layer before the layered control valve is lowered are used to calculate the initial annulus pressure of the i th layer, the initial annulus inflow of the i th layer, and the initial wellbore inflow of the i th layer;

[0009] Fourth, after the layered control valve changes the valve opening of the i th layer, the time of the change of the valve opening of the i th layer is taken as a cycle, and the initial annulus inflow of the i th layer and the initial wellbore inflow of the i th layer are combined to calculate the annulus pressure of the i th layer in each cycle through the annulus pressure change equation; the liquid production index of the i th layer, the formation pressure of the i th layer, and the annulus pressure of the i th layer in each cycle are used to calculate the annulus inflow of the i th layer in each cycle through the reservoir to annulus productivity equation; the flow coefficient of the i th layer, the control valve opening of the i th layer, the layered control valve flow area, the bottom hole flowing pressure of the i th layer, the fluid density of the i th layer, and the annulus pressure of the i th layer in each cycle are used to calculate the wellbore inflow of the i th layer in each cycle through the control valve productivity equation; this process is repeated with time as a cycle to iteratively calculate the annulus inflow of the i th layer, the wellbore inflow of the i th layer, and the annulus pressure of the i th layer until the annulus inflow of the i th layer is equal to the wellbore inflow of the i th layer, the iteration ends, and the subsequent wellbore inflow is calculated using the control valve productivity equation until the time cycle ends; the calculated wellbore inflow of the i th layer is fitted with the i th layer production of the actual oil well, and the flow coefficient of the i th layer is continuously adjusted; after successful fitting, the wellbore inflow of the i th layer and the flow coefficient of the i th layer are obtained;

[0010] Fifth, using the fitting of the i layer flow coefficient, combined with the above oil well into the layer control valve after the annulus storage effect of production fitting method, the oil well into the layer control valve production prediction of fixed well bottom flowing pressure.

[0011] In the above-mentioned layer control valve oil well production prediction method considering annulus storage effect, the static parameters are: the permeability of the i layer, the effective thickness of the i layer, the fluid viscosity of the i layer, the crude oil volume coefficient of the i layer, the drainage radius, the wellbore radius, the flow area of the layer control valve, the control valve opening of the i layer, the fluid density of the i layer, the formation pressure of the i layer, the annulus storage coefficient; the dynamic parameters are: the actual oil well production before the layer control valve is put in, the actual oil well i layer production after the layer control valve is put in, the well bottom flowing pressure of the i layer, the control valve opening change time of the i layer.

[0012] In the above-mentioned layer control valve oil well production prediction method considering annulus storage effect, the liquid production index calculation formula is: Wherein: Ji is the liquid production index of the i layer, m 3 / (d·MPa); Ki is the permeability of the i layer, 10 -3 μm 2 ; hi is the effective thickness of the i layer, m; μi is the fluid viscosity of the i layer, mPa·s; B o i is the crude oil volume coefficient of the i layer, dimensionless; re is the drainage radius, m; rw is the wellbore radius, m.

[0013] In the above-mentioned layer control valve oil well production prediction method considering annulus storage effect, the convergence condition of oil well production and actual oil well production fitting is expressed as: Wherein: E is the deviation value, dimensionless; m is the iteration number; is the actual oil well production of the jth day, m 3 / d; q j is the oil well production of the jth day, m 3 / d.

[0014] In the above-mentioned layer control valve oil well production prediction method considering annulus storage effect, the reservoir to annulus productivity equation is: qini=Ji(Pii-Pci), and the control valve productivity equation is: Wherein: q ini is the annulus inflow of the i layer, m 3 / d; q outi is the wellbore inflow of the i layer, m3 / d; P ci is the annulus pressure of the i layer; P wfi is the well bottom flowing pressure of the i layer, MPa; λ i is the flow coefficient of the i layer, dimensionless; σi Let A be the opening degree of the i-th layer, dimensionless; let A be the flow area of ​​the layer control valve, in mm. 2 ;ρ Li Let be the fluid density of the i-th layer, kg / m³ 3 .

[0015] In the above-mentioned method for predicting well production using a stratified control valve that considers the annular reservoir effect, the iterative fitting approach after changing the valve opening of the stratified control valve is as follows:

[0016] The first step is to combine the initial annular inflow q of the i-th layer calculated when the valve opening of the stratified control valve is not changed. i ′ ni and the initial wellbore inflow q of the i-th layer o ′ uti Calculate the change in annular production Δq in the i-th layer. Li , ΔqLi=q′ini-q′outi;

[0017] The second step is to use the calculated annular production change Δq of the i-th layer. Li Through the annular pressure change equation Calculate the change in annular pressure at layer i, and sum the current annular pressure P at layer i. ci Wherein: ΔP ci Δq represents the change in annular pressure at the i-th layer. Li t represents the change in annular output at the i-th layer; i d represents the time it takes for the valve opening of the i-th layer to change; C is the annular storage coefficient, which is dimensionless.

[0018] Third, using the time interval of valve opening change at layer i as the period, repeat steps one and two to iteratively calculate the annular inflow q at layer i in each period. ini The inflow rate q of the wellbore in the i-th layer outi and the annular pressure P of the i-th layer ci Until the annular inflow q of the i-th layer ini and the wellbore inflow q of the i-th layer outi When the values ​​are equal, the iteration ends, and the wellbore inflow q of the i-th layer is obtained. outi ;

[0019] Fourth step, when the annular inflow q of the i-th layer... ini and the wellbore inflow q of the i-th layer outi When they are equal, the reservoir-to-annular production capacity equation qini=Ji(Pii-Pci) and the control valve production capacity equation are combined. The annular inflow q of the i-th layer can then be calculated simultaneously. ini The inflow rate q of the wellbore in the i-th layer outi and the annular pressure P of the i-th layerci , to obtain the wellbore inflow rate q outi of the i-th layer;

[0020] Fifthly, the calculated wellbore inflow rate q outi of the i-th layer is obtained. The fitting is performed, and the flow coefficient λ i of the i-th layer is constantly adjusted. outi，j The calculated wellbore inflow rate q of the i-th layer is obtained.

[0021] Wherein, q outi，j is the wellbore inflow rate of the i-th layer, m 3 / d. is the production of the i-th layer of the actual oil well, m 3 / d.

[0022] Compared with the prior art, the method has the following beneficial effects: (1) the annular storage effect is combined to fit the production of the oil well with the set-in layered control valve, and the fitting effect is good; (2) the fitting is realized by programming, and the fitting process is time-saving and labor-saving; and (3) the method has strong generalizability. BRIEF DESCRIPTION OF DRAWINGS

[0023] In the drawings:

[0024] Figure 1 is the general technical roadmap of the method.

[0025] Figure 2 is the production fitting graph of the oil well without the set-in layered control valve.

[0026] Figure 3 is the production fitting graph of the oil well with the set-in layered control valve considering the annular storage effect.

[0027] Figure 4 is the production prediction graph of the oil well with the set bottom-hole flowing pressure of 4 MPa. DETAILED DESCRIPTION

[0028] The present application will be further described below in combination with the embodiments and the drawings.

[0029] The present application provides a layered control valve oil well production prediction method considering the annular storage effect, Figure 1 is the general technical roadmap of the method, and the method comprises the following steps:

[0030] Firstly, the static parameters of the target well, the dynamic parameters before the set-in layered control valve and the dynamic parameters after the set-in layered control valve are collected.

[0031] Second, before the layered control valve is put down, the permeability of the i-th layer, the effective thickness of the i-th layer, the fluid viscosity of the i-th layer, the oil volume coefficient of the i-th layer, the drainage radius, and the wellbore radius parameters are substituted into the liquid production index calculation formula to calculate the initial value of the liquid production index of the i-th layer. One day is taken as a cycle in the production data, the formation pressure of the i-th layer, the bottom hole flowing pressure of the i-th layer, and the calculated initial value of the liquid production index of the i-th layer are used to iteratively calculate the production of the i-th layer through the oil well flow productivity equation, and the production of each layer is added to obtain the production of an oil well; the liquid production index of the i-th layer is continuously adjusted, and the iteratively calculated oil well production is fitted with the actual oil well production; after successful fitting, the actual liquid production index of the i-th layer is obtained;

[0032] Third, the oil well with the layered control valve is divided into two cases of unchanged valve opening and changed valve opening; when the layered control valve does not change the valve opening of the i-th layer, the reservoir to annulus productivity equation and the control valve productivity equation are solved, the formation pressure of the i-th layer, the flow coefficient of the i-th layer, the control valve opening of the i-th layer, the flow area of the layered control valve, the bottom hole flowing pressure of the i-th layer, the fluid density of the i-th layer, and the fitted liquid production index of the i-th layer before the layered control valve is put down are used to calculate the initial annulus pressure of the i-th layer, the initial annulus inflow of the i-th layer, and the initial wellbore inflow of the i-th layer;

[0033] Fourth, after the layered control valve changes the valve opening of the i-th layer, the time when the valve opening of the i-th layer is changed is taken as a cycle, and the initial annulus inflow of the i-th layer, the initial wellbore inflow of the i-th layer, and the annulus pressure change equation are used to calculate the annulus pressure of the i-th layer in each cycle; the liquid production index of the i-th layer, the formation pressure of the i-th layer, and the annulus pressure of the i-th layer in each cycle are used to calculate the annulus inflow of the i-th layer in each cycle through the reservoir to annulus productivity equation; the flow coefficient of the i-th layer, the control valve opening of the i-th layer, the flow area of the layered control valve, the bottom hole flowing pressure of the i-th layer, the fluid density of the i-th layer, and the annulus pressure of the i-th layer in each cycle are used to calculate the wellbore inflow of the i-th layer in each cycle through the control valve productivity equation; this process is repeated with time as a cycle to iteratively calculate the annulus inflow of the i-th layer, the wellbore inflow of the i-th layer, and the annulus pressure of the i-th layer until the annulus inflow of the i-th layer is equal to the wellbore inflow of the i-th layer, and the iteration ends, and the subsequent wellbore inflow is calculated using the control valve productivity equation until the time cycle ends; the calculated wellbore inflow of the i-th layer is fitted with the actual i-th layer production of the oil well, and the flow coefficient of the i-th layer is continuously adjusted; after successful fitting, the wellbore inflow of the i-th layer and the flow coefficient of the i-th layer are obtained;

[0034] Fifth, the fitted flow coefficient of the i-th layer is used in combination with the above-mentioned production fitting method of the annulus reservoir effect after the layered control valve is put down to predict the bottom hole flowing pressure of the oil well with the layered control valve.

[0035] Further, the static parameters are: the permeability of the ith layer, the effective thickness of the ith layer, the fluid viscosity of the ith layer, the oil volume coefficient of the ith layer, the drainage radius, the wellbore radius, the flow area of the layered control valve, the control valve opening of the ith layer, the fluid density of the ith layer, the formation pressure of the ith layer, the annulus storage coefficient; the dynamic parameters are: the actual oil well production before the layered control valve is lowered, the actual oil well production of the ith layer after the layered control valve is lowered, the bottom-hole flowing pressure of the ith layer, the control valve opening change time of the ith layer.

[0036] Further, the liquid production index calculation formula is: Wherein: Ji is the liquid production index of the ith layer, m 3 / (d·MPa); Ki is the permeability of the ith layer, 10 -3 μm 2 ; h i is the effective thickness of the ith layer, m; μ i is the fluid viscosity of the ith layer, mPa·s; B oi is the oil volume coefficient of the ith layer, dimensionless; r e is the drainage radius, m; r w is the wellbore radius, m.

[0037] Further, the convergence condition of the oil well production and the actual oil well production fitting is expressed as: Wherein: E is the deviation value, dimensionless; m is the iteration number; is the actual oil well production on the jth day, m 3 / d; q j is the oil well production on the jth day, m 3 / d.

[0038] Further, the reservoir to annulus deliverability equation is: qini=Ji(Pii-Pci), and the control valve deliverability equation is: Wherein: q ini is the annulus inflow of the ith layer, m3 / d; q outi is the wellbore inflow of the ith layer, m3 / d; P ci is the annulus pressure of the ith layer; P wfi is the bottom-hole flowing pressure of the ith layer, MPa; λ i is the flow coefficient of the ith layer, dimensionless; σ i is the opening of the ith layer, dimensionless; A is the flow area of the layered control valve, mm 2 ; ρ Li is the fluid density of the ith layer, kg / m 3 .

[0039] Further, the iteration fitting idea after the layered control valve changes the valve opening is:

[0040] First step, combined with the initial annulus inflow qini of the ith layer calculated when the layered control valve does not change the valve opening i ni and the initial wellbore inflow qouti of the ith layer o uti Calculate the annulus production change Δq of the ith layer Li , ΔqLi=q'ini-q'outi;

[0041] Second step, using the calculated annulus production change Δq of the ith layer Li , through the annulus pressure change equation Calculate the annulus pressure change of the ith layer, and accumulate the annulus pressure P of the current ith layer ci ; Where: ΔP ci is the annulus pressure change of the ith layer; Δq Li is the annulus production change of the ith layer; t i is the valve opening change time of the ith layer, d; C is the annulus storage coefficient, dimensionless;

[0042] Third step, taking the valve opening change time of the ith layer as a period, repeating the first step and the second step, iteratively calculating the annulus inflow q of the ith layer ini , the wellbore inflow q of the ith layer outi and the annulus pressure P of the ith layer ci of each period until the annulus inflow q of the ith layer ini and the wellbore inflow q of the ith layer outi are equal, the iteration is ended, and the wellbore inflow q of the ith layer outi is obtained;

[0043] Fourth step, when the annulus inflow q of the ith layer ini and the wellbore inflow q of the ith layer outi are equal, at this time the reservoir to annulus productivity equation qini=Ji(Pii-Pci) and control valve productivity equation can be calculated simultaneously to obtain the subsequent annulus inflow q of the ith layer ini , the wellbore inflow q of the ith layer outi and the annulus pressure P of the ith layer ci , and the subsequent wellbore inflow q of the ith layer outi is obtained;

[0044] Fifth step, the calculated wellbore inflow q of the ith layer outi is fitted with the actual oil well production of the ith layer , and the flow coefficient λ of the ith layer is continuously adjusted i , to seek the calculated wellbore inflow q of the ith layer outi，j ​​The actual oil well layer i production The convergence condition of the fitting is expressed as:

[0045] Wherein: q outi，j is the wellbore inflow of the i layer, m 3 / d; is the actual oil well layer i production, m 3 / d.

[0046] Taking the three-layer exploitation oil well X-1 developed by offshore water injection as an example, the fluid viscosity of the oil well is 13.061 mPa·s, the crude oil volume coefficient is 1.055, the drainage radius is 145 m, the wellbore radius is 0.122 m, and the remaining parameters are shown in Table 1. Before running the layered control valve, the fluid production index of each layer is calculated according to these parameters, and the actual fitting fluid production index of each layer is obtained, the results are shown in Table 1, the production fitting effect diagram is shown in Figure 2 , and the fitting error is 7.84%. After running the layered control valve, the layered production fitting is carried out by considering the annular storage effect under the condition that the opening of the layered control valve changes, the production fitting effect diagram is shown in Figure 3 , the fitting errors of the three layers are 4.28%, 5.16% and 5.52% respectively, and the flow coefficient results obtained by fitting are shown in Table 1. According to the flow coefficient obtained by fitting, the bottom hole flowing pressure of the oil well is set to 4 MPa, and the production prediction is carried out with the same layered control valve opening, and the production prediction diagram is shown in Figure 4 .

[0047] Table 1 Parameters and fitting parameters of oil well X-1

[0048]

[0049] Compared with the prior art, the present application has the following beneficial effects: (1) the annular storage effect is combined to fit the production of the oil well with the layered control valve, and the fitting effect is good; (2) the fitting is realized by programming, and the fitting process is time-saving and labor-saving; (3) it has strong generalizability.

[0050] Finally, it should be explained that: the above examples are only used to illustrate but not to limit the technical solutions of the present application, although the present application has been described in detail with reference to the above examples, those skilled in the art should understand that: the present application can still be modified or equivalently replaced without departing from the spirit and scope of the present application, any modification or partial replacement should be covered in the scope of the claims of the present application.

Claims

1. A method for predicting production in stratified control valve oil wells considering annular reservoir effects, characterized in that, The method includes the following steps: First, collect the static parameters of the target oil well, the dynamic parameters before the stratification control valve is installed, and the dynamic parameters after the stratification control valve is installed. Second, before the stratification control valve is installed, the permeability, effective thickness, fluid viscosity, crude oil volume coefficient, drainage radius, and wellbore radius of the i-th layer are substituted into the fluid production index calculation formula to obtain the initial value of the fluid production index for the i-th layer. Taking one day as a cycle in the production data, the formation pressure and bottom hole flowing pressure of the i-th layer are used to calculate the production of the i-th layer using the initial value of the fluid production index. The production of the i-th layer is then iteratively calculated using the oil well flow production capacity equation, and the production of each layer is added together to obtain an oil well production. The fluid production index of the i-th layer is continuously adjusted, and the iteratively calculated oil well production is fitted with the actual oil well production. After successful fitting, the actual fluid production index of the i-th layer is obtained. Third, the wells with stratified control valves are divided into two cases: those with unchanged valve opening and those with changed valve opening. When the stratified control valve does not change the valve opening of the i-th layer, the reservoir-annular production capacity equation and the control valve production capacity equation are combined. The initial annular pressure, initial annular inflow, and initial wellbore inflow of the i-th layer are calculated using the formation pressure of the i-th layer, the flow coefficient of the i-th layer, the control valve opening of the i-th layer, the flow area of ​​the stratified control valve, the bottom hole flowing pressure of the i-th layer, the fluid density of the i-th layer, and the production index of the i-th layer obtained before the stratified control valve was installed. Fourth, after the stratified control valve changes the valve opening of the i-th layer, the annular pressure of the i-th layer in each cycle is calculated using the time interval of the valve opening change of the i-th layer as the period, combined with the initial annular inflow rate and the initial wellbore inflow rate of the i-th layer, through the annular pressure change equation; the annular inflow rate of the i-th layer in each cycle is calculated using the reservoir-to-annular production capacity equation, using the fluid production index of the i-th layer, the formation pressure of the i-th layer, and the annular pressure of the i-th layer in each cycle; and the annular inflow rate of the i-th layer in each cycle is calculated using the flow coefficient of the i-th layer, the control valve opening of the i-th layer, the flow area of ​​the stratified control valve, the bottom hole flowing pressure of the i-th layer, the fluid density of the i-th layer, and the annular pressure of the i-th layer in each cycle. The annular pressure of one cycle is used to calculate the wellbore inflow rate of the i-th layer in each cycle using the control valve productivity equation. This process is repeated with time as the cycle, iteratively calculating the annular inflow rate, wellbore inflow rate, and annular pressure of the i-th layer until the annular inflow rate of the i-th layer equals the wellbore inflow rate. The iteration ends, and the subsequent wellbore inflow rate is calculated using the control valve productivity equation until the time cycle ends. The calculated wellbore inflow rate of the i-th layer is fitted with the actual production of the i-th layer of the oil well, and the flow coefficient of the i-th layer is continuously adjusted. If the fit is successful, the wellbore inflow rate and flow coefficient of the i-th layer are obtained. Fifth, using the flow coefficient of the i-th layer obtained by fitting, combined with the production fitting method of the annular storage effect generated after the oil well is equipped with the stratification control valve, the production of the oil well with the bottom hole flowing pressure is predicted.

2. The method for predicting production of stratified control valve oil wells considering annular reservoir effects according to claim 1, characterized in that: The static parameters are: permeability of the i-th layer, effective thickness of the i-th layer, fluid viscosity of the i-th layer, crude oil volume coefficient of the i-th layer, drainage radius, wellbore radius, flow area of ​​the stratification control valve, opening degree of the control valve of the i-th layer, fluid density of the i-th layer, formation pressure of the i-th layer, and annular reservoir coefficient; the dynamic parameters are: actual well production before the stratification control valve is installed, actual well production of the i-th layer after the stratification control valve is installed, bottom hole flowing pressure of the i-th layer, and time for the opening degree of the control valve of the i-th layer to change.

3. The method for predicting production of stratified control valve oil wells considering annular reservoir effects according to claim 1, characterized in that: The formula for calculating the fluid collection index is: Among them: J i Let m be the fluid collection index of the i-th layer. 3 / (d·MPa); K i Let be the permeability of the i-th layer, 10 -3 μm 2 h i Let m be the effective thickness of the i-th layer; μ be the effective thickness of the i-th layer. i B is the fluid viscosity of the i-th layer, in mPa·s; oi r is the crude oil volume coefficient of the i-th layer, dimensionless; e r is the discharge radius, in meters (m). w Let be the radius of the wellbore, in meters (m).

4. The method for predicting production of stratified control valve oil wells considering annular reservoir effects according to claim 1, characterized in that: The convergence condition for fitting the oil well production rate to the actual oil well production rate is expressed as follows: Where: E is the deviation value, which is dimensionless; m is the number of iterations; m represents the actual well production on day j. 3 / d;q j For the oil well production on day j, m 3 / d.

5. The method for predicting production of stratified control valve oil wells considering annular reservoir effects according to claim 1, characterized in that: The reservoir-to-annular productivity equation is: q ini =J i (P ii -P ci The control valve capacity equation is as follows: Where: q ini Let m be the annular inflow of the i-th layer. 3 / d;q outi The wellbore inflow rate at layer i, m 3 / d;P ci P is the annular pressure of the i-th layer; wfi λ is the bottom-hole flowing pressure of the i-th layer, in MPa; i σ is the flow coefficient of the i-th layer, dimensionless; i Let A be the opening degree of the i-th layer, dimensionless; let A be the flow area of ​​the layer control valve, in mm. 2 ;ρ Li Let be the fluid density of the i-th layer, kg / m³ 3 .

6. The method for predicting production of stratified control valve oil wells considering annular reservoir effects according to claim 1, characterized in that: The iterative fitting approach described above for changing the valve opening degree in a tiered control valve is as follows: The first step is to combine the initial annular inflow q′ of the i-th layer calculated when the valve opening of the stratified control valve is not changed. ini and the initial wellbore inflow rate q′ of the i-th layer outi Calculate the change in annular production Δq in the i-th layer. Li , Δq Li =q′ ini -q′ outi ; The second step is to use the calculated annular production change Δq of the i-th layer. Li Through the annular pressure change equation Calculate the change in annular pressure at layer i, and sum the current annular pressure P at layer i. ci ; Where: ΔP ci Δq represents the change in annular pressure at the i-th layer. Li t represents the change in annular output at the i-th layer; i d represents the time it takes for the valve opening of the i-th layer to change; C is the annular storage coefficient, which is dimensionless. Third, using the time interval of valve opening change at layer i as the period, repeat steps one and two to iteratively calculate the annular inflow q at layer i in each period. ini The inflow rate q of the wellbore in the i-th layer outi and the annular pressure P of the i-th layer ci Until the annular inflow q of the i-th layer ini and the wellbore inflow q of the i-th layer outi When the values ​​are equal, the iteration ends, and the wellbore inflow q of the i-th layer is obtained. outi ; Fourth step, when the annular inflow q of the i-th layer... ini and the wellbore inflow q of the i-th layer outi When they are equal, the simultaneous reservoir-to-annular productivity equation q ini =J i (P ii -P ci ) and control valve capacity equation The annular inflow q of the i-th layer can then be calculated simultaneously. ini The inflow rate q of the wellbore in the i-th layer outi and the annular pressure P of the i-th layer ci The inflow rate q of the i-th wellbore is obtained. outi ; The fifth step is to calculate the wellbore inflow rate q of the i-th layer. outi Actual production of the i-th layer of the oil well The fitting process is performed, and the flow coefficient λ of the i-th layer is continuously adjusted. i Seek the calculated wellbore inflow rate q for the i-th layer. outi，j Production of the i-th layer of the actual oil well The best fit, and the convergence condition of the fit are expressed as: Where: q outi，j Let m be the wellbore inflow rate of the i-th layer. 3 / d; m represents the actual production of the i-th layer of the oil well. 3 / d.

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