Layered control valve oil well yield prediction method considering annulus reservoir effect

Abstract

The invention belongs to the field of oil and gas field development, and particularly relates to a layered control valve oil well yield prediction method considering an annulus reservoir effect. According to the method, by considering the pressure change and fluid flow characteristics in the annulus, firstly, the liquid production index of each layer is obtained through fitting before the layering control valve is put in, and after the layering control valve is put in, the annulus pressure under the influence of the change opening degree of the layering control valve is calculated through iteration; the method comprises the following steps of: calculating annular pressure of the oil well, calculating annular inflow and wellbore inflow by using the calculated annular pressure, finally fitting the wellbore inflow obtained by calculation with actual oil well yield to obtain a flow coefficient of each layer, and predicting the yield of the fixed flowing bottomhole pressure through the flow coefficient of each layer, so that the influence of the annular reservoir effect on the yield prediction is solved. The method not only improves the precision and stability of yield prediction, but also has wide applicability and popularization value, and provides powerful support for efficient development of multilayer oil reservoirs.

Description

Technical Field

[0001] The invention belongs to the field of oil and gas field development, and in particular relates to a layered control valve oil well production prediction method taking annular space storage effect into consideration. Background Art

[0002] In the process of multi-layer oil well development, accurate prediction of oil well production is of great significance for optimizing production strategies, improving recovery and reducing operating costs. Traditional oil well production prediction methods are mainly based on empirical formulas or numerical simulations, but these methods often ignore the impact of annular storage effect on production, resulting in a large deviation between the prediction results and the actual situation. The annular storage effect refers to the impact of fluid storage and release in the annulus on production during the production process of multi-layer oil wells when the stratified control valve is lowered. In particular, after a period of closure, the target layer will be opened after the pressure is blocked, resulting in a sharp increase in production in the initial stage. This effect will affect the transient pressure response and production changes of the oil well, and thus affect the development effect of the entire reservoir. Although existing technologies such as empirical formula method and numerical simulation method can predict production to a certain extent, the prediction accuracy and reliability are limited due to the lack of consideration of the annular storage effect.

[0003] In order to solve the above problems, the present invention proposes a method for predicting oil well production with a stratified control valve that takes into account the annular reservoir effect. The method introduces an annular reservoir effect model, considers the pressure changes and fluid flow characteristics in the annular space, and combines the dynamic adjustment strategy of the opening of the stratified control valve to achieve high-precision prediction of oil well production. The present invention not only improves the accuracy and stability of production prediction, but also has wide applicability and promotion value, providing strong support for the efficient development of multi-layer oil reservoirs. Summary of the invention

[0004] The purpose of the present invention is to solve the influence of annular space reservoir effect on production prediction, and propose a production prediction method of stratified control valve oil wells considering annular space reservoir effect. The method first obtains the liquid production index of each layer by fitting before the stratified control valve is lowered, and after the stratified control valve is lowered, the annular space pressure under the influence of the change of the opening of the stratified control valve is calculated by iteration, and the annular space inflow and the wellbore inflow are calculated by using the calculated annular space pressure, and finally the calculated wellbore inflow is fitted with the actual oil well production to obtain the flow coefficient of each layer, and the production prediction of the fixed bottom hole pressure can be carried out through the flow coefficient of each layer, which solves the influence of the annular space reservoir effect on the production prediction.

[0005] To achieve the above object, the present invention provides a method for predicting the production of a stratified control valve oil well taking into account the annular reservoir effect, the method comprising the following steps:

[0006] First, the static parameters of the target well, the dynamic parameters before the stratified control valve is lowered, and the dynamic parameters after the stratified control valve is lowered are collected;

[0007] Second, before the stratified 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 crude 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. Taking one day in the production data as a cycle, the formation pressure of the i-th layer, the bottom hole flow pressure of the i-th layer and the 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 capacity equation, and the production of each layer is added to obtain an oil well production; the i-th layer liquid production index is continuously adjusted, and the iteratively calculated oil well production is fitted with the actual oil well production; after the fitting is successful, the actual i-th layer liquid production index is obtained;

[0008] Third, the oil wells with the stratified control valve installed are divided into two cases: the valve opening is not changed and the valve opening is changed; when the stratified control valve does not change the valve opening of the i-th layer, the reservoir-to-annulus capacity equation and the control valve capacity equation are combined, and the initial annulus 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 flow pressure of the i-th layer, the fluid density of the i-th layer and the liquid production index of the i-th layer obtained by fitting before the stratified control valve is installed 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 stratified control valve changes the valve opening of the i-th layer, the time of the valve opening change of the i-th layer is taken as the period, and the annular pressure of the i-th layer in each cycle is calculated by the annular pressure change equation in combination with the initial annular inflow of the i-th layer and the initial wellbore inflow of the i-th layer; the annular inflow of the i-th layer in each cycle is calculated by the reservoir to annular capacity equation using the liquid 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; 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 flow 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 are used to calculate the annular inflow of the i-th layer in each cycle; The annular pressure of one cycle is used to calculate the wellbore inflow of each cycle of the i-th layer through the control valve capacity equation; this process is repeated with time as the cycle, and the annular inflow of the i-th layer, the wellbore inflow of the i-th layer and the annular pressure of the i-th layer are iteratively calculated until the annular 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 capacity 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; if the fitting is successful, the wellbore inflow of the i-th layer and the flow coefficient of the i-th layer are obtained;

[0010] 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 stratified control valve is installed in the oil well, the production prediction of the oil well with a stratified control valve installed at a constant bottom hole pressure is carried out.

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

[0012] In the above-mentioned method for predicting the production of oil wells with stratified control valves taking into account the annular reservoir effect, the liquid production index calculation formula is: Where: Ji is the liquid extraction index of the i-th layer, m 3 / (d·MPa); Ki is the permeability of the i-th layer, 10 -3 μm 2 ; hi is the effective thickness of the i-th layer, m; μi is the fluid viscosity of the i-th layer, mPa·s; B o i is the volume coefficient of crude oil in the i-th layer, dimensionless; re is the discharge radius, m; rw is the wellbore radius, m.

[0013] In the above-mentioned method for predicting oil well production with a stratified control valve considering the annular reservoir effect, the convergence condition for fitting the oil well production with the actual oil well production is expressed as: Where: E is the deviation value, dimensionless; m is the number of iterations; 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.

[0014] In the above-mentioned stratified control valve oil well production prediction method considering the annular space reservoir effect, the reservoir to annular space production capacity equation is: qini = Ji (Pii-Pci), and the control valve production capacity equation is: Where: q ini is the annular inflow of the i-th layer, m 3 / d;q outi Wellbore inflow of the i-th layer, m3 / d; P ci is the annular pressure of the i-th layer; P wfi is the bottom hole flowing pressure of the i-th layer, MPa; i is the flow coefficient of the i-th layer, dimensionless; σi is the opening of the i-th layer, dimensionless; A is the flow area of ​​the stratified control valve, mm 2 ρ Li is the fluid density of the i-th layer, kg / m 3 .

[0015] In the above-mentioned method for predicting oil well production using a stratified control valve taking into account the annular reservoir effect, the iterative fitting idea after the stratified control valve changes the valve opening is:

[0016] In the first step, the initial annular inflow q of the i-th layer is calculated when the stratified control valve does not change the valve opening i ' ni and the initial wellbore inflow q of the i-th layer o ' uti Calculate the annular production change Δq of 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 annulus pressure change equation Calculate the change in annular pressure of the i-th layer, and accumulate and calculate the current annular pressure P of the i-th layer ci ; Where: ΔP ci is the change in annular pressure of the i-th layer; Δq Li is the change in annular production of the i-th layer; t i is the time of change of valve opening of the i-th layer, d; C is the annular storage coefficient, dimensionless;

[0018] The third step is to take the time of the valve opening change of the i-th layer as the cycle, repeat the first and second steps, and iteratively calculate the annular inflow q of the i-th layer in each cycle ini , the wellbore inflow q of 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 equal, the iteration ends, and the wellbore inflow q of the i-th layer is obtained outi ;

[0019] Step 4: When the annular inflow q of the i-th layer ini and the wellbore inflow q of the i-th layer outi When the reservoir-to-annulus capacity equation is equal, the control valve capacity equation is combined: The subsequent annular inflow q of the i-th layer can be calculated by simultaneous calculation ini , the wellbore inflow q of the i-th layer outi and the annular pressure P of the i-th layerci , and the subsequent wellbore inflow q of the i-th layer is obtained outi ;

[0020] The fifth step is to calculate the wellbore inflow q of the i-th layer. outi Actual oil well production at layer i Fitting and continuously adjusting the flow coefficient λ of the i-th layer i , find the calculated wellbore inflow q of the i-th layer outi，j The actual production of the i-th layer of the oil well The best fit of is, and the convergence condition of the fit is expressed as:

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

[0022] Compared with the prior art, the present invention has the following beneficial effects: (1) the production of oil wells with stratified control valves inserted is fitted by combining the annular space storage effect, and the fitting effect is better; (2) the fitting is realized by programming, and the fitting process is time-saving and labor-saving; (3) the applicability is strong. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In the attached picture:

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

[0025] Figure 2 This is the production fitting diagram of the oil well without the stratified control valve.

[0026] Figure 3 It is a production fitting diagram considering the annular storage effect after the stratified control valve is installed in the oil well.

[0027] Figure 4 This is the production prediction diagram after the oil well is set to a bottom hole flowing pressure of 4 MPa. DETAILED DESCRIPTION

[0028] The present invention will be further described below in conjunction with the embodiments and accompanying drawings;

[0029] The present invention provides a method for predicting the production of oil wells with layered control valves taking into account the annular storage effect. Figure 1 It is the overall technical roadmap of the method, which includes the following steps:

[0030] First, the static parameters of the target well, the dynamic parameters before the stratified control valve is lowered, and the dynamic parameters after the stratified control valve is lowered are collected;

[0031] Second, before the stratified 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 crude 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. Taking one day in the production data as a cycle, the formation pressure of the i-th layer, the bottom hole flow pressure of the i-th layer and the 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 capacity equation, and the production of each layer is added to obtain an oil well production; the i-th layer liquid production index is continuously adjusted, and the iteratively calculated oil well production is fitted with the actual oil well production; after the fitting is successful, the actual i-th layer liquid production index is obtained;

[0032] Third, the oil wells with the stratified control valve installed are divided into two cases: the valve opening is not changed and the valve opening is changed; when the stratified control valve does not change the valve opening of the i-th layer, the reservoir-to-annulus capacity equation and the control valve capacity equation are combined, and the initial annulus 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 flow pressure of the i-th layer, the fluid density of the i-th layer and the liquid production index of the i-th layer obtained by fitting before the stratified control valve is installed 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 stratified control valve changes the valve opening of the i-th layer, the time of the valve opening change of the i-th layer is taken as the period, and the annular pressure of the i-th layer in each cycle is calculated by the annular pressure change equation in combination with the initial annular inflow of the i-th layer and the initial wellbore inflow of the i-th layer; the annular inflow of the i-th layer in each cycle is calculated by the reservoir to annular capacity equation using the liquid 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; 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 flow 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 are used to calculate the annular inflow of the i-th layer in each cycle; The annular pressure of one cycle is used to calculate the wellbore inflow of each cycle of the i-th layer through the control valve capacity equation; this process is repeated with time as the cycle, and the annular inflow of the i-th layer, the wellbore inflow of the i-th layer and the annular pressure of the i-th layer are iteratively calculated until the annular 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 capacity 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; if the fitting is successful, the wellbore inflow of the i-th layer and the flow coefficient of the i-th layer are obtained;

[0034] 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 stratified control valve is installed in the oil well, the production prediction of the oil well with a stratified control valve installed at a constant bottom hole pressure is carried out.

[0035] Furthermore, the static parameters are: the permeability of the i-th layer, the effective thickness of the i-th layer, the fluid viscosity of the i-th layer, the crude oil volume coefficient of the i-th layer, the leakage radius, the wellbore radius, the flow area of ​​the stratified control valve, the control valve opening of the i-th layer, the fluid density of the i-th layer, the formation pressure of the i-th layer, and the annulus storage coefficient; the dynamic parameters are: the actual oil well production before the stratified control valve is lowered, the actual oil well production of the i-th layer after the stratified control valve is lowered, the bottom hole pressure of the i-th layer, and the control valve opening change time of the i-th layer.

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

[0037] Furthermore, the convergence condition for fitting the oil well production to the actual oil well production is expressed as: Where: E is the deviation value, dimensionless; m is the number of iterations; 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] Furthermore, the reservoir to annulus capacity equation is: qini=Ji(Pii-Pci), and the control valve capacity equation is: Where: q ini is the annular inflow of the i-th layer, m3 / d; q outi Wellbore inflow of the i-th layer, m3 / d; P ci is the annular pressure of the i-th layer; P wfi is the bottom hole flowing pressure of the i-th layer, MPa; i is the flow coefficient of the i-th layer, dimensionless; σ i is the opening of the i-th layer, dimensionless; A is the flow area of ​​the stratified control valve, mm 2 ρ Li is the fluid density of the i-th layer, kg / m 3 .

[0039] Furthermore, the iterative fitting idea after the stratified control valve changes the valve opening is:

[0040] In the first step, the initial annular inflow q of the i-th layer is calculated when the stratified control valve does not change the valve opening i ' ni and the initial wellbore inflow q of the i-th layer o ' uti Calculate the annular production change Δq of the i-th layer Li , ΔqLi=q′ini-q′outi;

[0041] The second step is to use the calculated annular production change Δq of the i-th layer Li , through the annulus pressure change equation Calculate the change in annular pressure of the i-th layer, and accumulate and calculate the current annular pressure P of the i-th layer ci ; Where: ΔP ci is the change in annular pressure of the i-th layer; Δq Li is the change in annular production of the i-th layer; t i is the time of valve opening change of layer i, d; C is the annular storage coefficient, dimensionless;

[0042] The third step is to take the time of the valve opening change of the i-th layer as the cycle, repeat the first and second steps, and iteratively calculate the annular inflow q of the i-th layer in each cycle ini , the wellbore inflow q of 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 equal, the iteration ends, and the wellbore inflow q of the i-th layer is obtained outi ;

[0043] Step 4: When the annular inflow q of the i-th layer ini and the wellbore inflow q of the i-th layer outi When the reservoir-to-annulus capacity equation is equal, the control valve capacity equation is combined: The subsequent annular inflow q of the i-th layer can be calculated by simultaneous calculation ini , the wellbore inflow q of the i-th layer outi and the annular pressure P of the i-th layer ci , and the subsequent wellbore inflow q of the i-th layer is obtained outi ;

[0044] The fifth step is to calculate the wellbore inflow q of the i-th layer. outi Actual oil well production at layer i Fitting and continuously adjusting the flow coefficient λ of the i-th layer i , find the calculated wellbore inflow q of the i-th layer outi，jThe actual production of the i-th layer of the oil well The best fit of is, and the convergence condition of the fit is expressed as:

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

[0046] Taking the three-layer production well X-1 developed by offshore water injection as an example, the fluid viscosity of the oil well is 13.061mPa·s, the crude oil volume coefficient is 1.055, the oil drainage radius is 145m, the wellbore radius is 0.122m, and the other parameters are shown in Table 1. Before the stratified control valve is lowered, the production index of each layer is calculated based on these parameters and the production index of each layer obtained by actual fitting is shown in Table 1. The production fitting effect diagram is shown in Figure 2 The fitting error is 7.84%. After the stratified control valve is lowered, the stratified production fitting is performed by considering the annular storage effect when the opening of each stratified control valve is changed. 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. The fitting flow coefficient results are shown in Table 1. According to the fitting flow coefficient, the bottom hole pressure of the oil well is set to 4MPa, and the production prediction is carried out with the same stratified control valve opening. 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 invention has the following beneficial effects: (1) the production of oil wells with stratified control valves inserted is fitted by combining the annular space storage effect, and the fitting effect is better; (2) the fitting is realized by programming, and the fitting process is time-saving and labor-saving; (3) the applicability is strong.

[0050] Finally, it should be noted that the above embodiments are only used to illustrate rather than limit the technical solutions of the present invention. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that the present invention can still be modified or replaced by equivalents. Any modification or partial replacement that does not depart from the spirit and scope of the present invention should be included in the scope of the claims of the present invention.

Claims

1. A method for predicting oil well production with a stratified control valve considering annular reservoir effect, characterized in that: The method comprises the following steps: First, the static parameters of the target oil well, the dynamic parameters before the stratified control valve is lowered, and the dynamic parameters after the stratified control valve is lowered are collected; Second, before the stratified 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 crude 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. Taking one day in the production data as a cycle, the formation pressure of the i-th layer, the bottom hole flow pressure of the i-th layer and the 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 capacity equation, and the production of each layer is added to obtain an oil well production; the i-th layer liquid production index is continuously adjusted, and the iteratively calculated oil well production is fitted with the actual oil well production; after the fitting is successful, the actual i-th layer liquid production index is obtained; Third, the oil wells with the stratified control valve installed are divided into two cases: the valve opening is not changed and the valve opening is changed; when the stratified control valve does not change the valve opening of the i-th layer, the reservoir-to-annulus capacity equation and the control valve capacity equation are combined, and the initial annulus 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 flow pressure of the i-th layer, the fluid density of the i-th layer and the liquid production index of the i-th layer obtained by fitting before the stratified control valve is installed 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; Fourth, after the stratified control valve changes the valve opening of the i-th layer, the time of the valve opening change of the i-th layer is taken as the period, and the annular pressure of the i-th layer in each cycle is calculated by the annular pressure change equation in combination with the initial annular inflow of the i-th layer and the initial wellbore inflow of the i-th layer; the annular inflow of the i-th layer in each cycle is calculated by the reservoir to annular capacity equation using the liquid 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; 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 flow 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 are used to calculate the annular inflow of the i-th layer in each cycle; The annular pressure of one cycle is used to calculate the wellbore inflow of each cycle of the i-th layer through the control valve capacity equation; this process is repeated with time as the cycle, and the annular inflow of the i-th layer, the wellbore inflow of the i-th layer and the annular pressure of the i-th layer are iteratively calculated until the annular 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 capacity 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; if the fitting is successful, the wellbore inflow of the i-th layer and the 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 stratified control valve is installed in the oil well, the production prediction of the oil well with a stratified control valve installed at a constant bottom hole pressure is carried out.

2. The method for predicting oil well production with a stratified control valve taking into account annular reservoir effect according to claim 1, characterized in that: The static parameters are: the permeability of the i-th layer, the effective thickness of the i-th layer, the fluid viscosity of the i-th layer, the crude oil volume coefficient of the i-th layer, the leakage radius, the wellbore radius, the flow area of ​​the stratified control valve, the control valve opening of the i-th layer, the fluid density of the i-th layer, the formation pressure of the i-th layer, and the annulus storage coefficient; the dynamic parameters are: the actual oil well production before the stratified control valve is lowered, the actual oil well production of the i-th layer after the stratified control valve is lowered, the bottom hole flow pressure of the i-th layer, and the control valve opening change time of the i-th layer.

3. The method for predicting oil well production with a stratified control valve taking into account annular reservoir effect according to claim 1, characterized in that: The calculation formula of the liquid extraction index is: Among them: J i is the liquid extraction index of the i-th layer, m 3 / (d·MPa); K i is the permeability of the i-th layer, 10 -3 μm 2 ;h i is the effective thickness of the i-th layer, m; μ i is the fluid viscosity of the i-th layer, mPa·s; B oi is the crude oil volume coefficient of the i-th layer, dimensionless; r e is the discharge radius, m; r w is the wellbore radius, m.

4. The method for predicting oil well production with a stratified control valve taking into account annular reservoir effect according to claim 1, characterized in that: The convergence condition of the oil well production and the actual oil well production fitting is expressed as: Where: E is the deviation value, dimensionless; m is the number of iterations; 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.

5. The method for predicting oil well production with a stratified control valve taking into account annular reservoir effect according to claim 1, characterized in that: The reservoir-to-annulus productivity equation is: ini =J i (P ii -P ci ), the control valve capacity equation is: Where: q ini is the annular inflow of the i-th layer, m 3 / d;q outi The wellbore inflow of the i-th layer, m 3 / d;P ci is the annular pressure of the i-th layer; P wfi is the bottom hole flowing pressure of the i-th layer, MPa; i is the flow coefficient of the i-th layer, dimensionless; σ i is the opening of the i-th layer, dimensionless; A is the flow area of ​​the stratified control valve, mm 2 ρ Li is the fluid density of the i-th layer, kg / m 3 .

6. The method for predicting oil well production with a stratified control valve taking into account annular reservoir effect according to claim 1, characterized in that: The iterative fitting idea after the stratified control valve changes the valve opening is: In the first step, the initial annular inflow q′ of the i-th layer is calculated when the stratified control valve does not change the valve opening ini and the initial wellbore inflow q′ of the i-th layer outi Calculate the annular production change Δq of 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 annulus pressure change equation Calculate the change in annular pressure of the i-th layer, and accumulate and calculate the current annular pressure P of the i-th layer ci ; Where: ΔP ci is the change in annular pressure of the i-th layer; Δq Li is the change in annular production of the i-th layer; t i is the time of change of valve opening of the i-th layer, d; C is the annular storage coefficient, dimensionless; The third step is to take the time of the valve opening change of the i-th layer as the cycle, repeat the first and second steps, and iteratively calculate the annular inflow q of the i-th layer in each cycle ini , the wellbore inflow q of 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 equal, the iteration ends, and the wellbore inflow q of the i-th layer is obtained outi ; Step 4: When the annular inflow q of the i-th layer ini and the wellbore inflow q of the i-th layer outi When the reservoir-to-annulus production capacity equation is equal, q ini =J i (P ii -P ci ) and the control valve capacity equation The subsequent annular inflow q of the i-th layer can be calculated by simultaneous calculation ini , the wellbore inflow q of the i-th layer outi and the annular pressure P of the i-th layer ci , and the subsequent wellbore inflow q of the i-th layer is obtained outi ; The fifth step is to calculate the wellbore inflow q of the i-th layer. outi Actual oil well production at layer i Fitting and continuously adjusting the flow coefficient λ of the i-th layer i , find the calculated wellbore inflow q of the i-th layer outi，j The actual production of the i-th layer of the oil well The best fit of is, and the convergence condition of the fit is expressed as: Where: q outi，j is the wellbore inflow of the i-th layer, m 3 / d; is the actual production of the i-th layer of the oil well, m 3 / d.

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