Condensate gas well oil-gas two-phase flow energy production prediction method considering stress sensitivity

Abstract

The invention discloses a condensate gas well oil-gas two-phase flow energy production prediction method considering stress sensitivity, and the method comprises the following steps: S1, dividing an oil-gas two-phase seepage stage of a condensate gas reservoir into three seepage periods: morning, noon and evening, and building a seepage physical model of each seepage period; s2, establishing a pseudo-pressure function considering stress sensitivity in each seepage period based on the seepage physical model, and establishing an oil-gas two-phase flow energy production equation considering stress sensitivity based on the seepage physical model; s3, judging the seepage period of the oil-gas two-phase seepage of the target condensate gas reservoir, and selecting a pseudo-pressure function of the corresponding seepage period according to a judgment result to calculate the pseudo-pressure of the pseudo-pressure function; and S4, predicting the productivity according to the pseudo-pressure calculation result of the oil-gas two-phase seepage of the target condensate gas reservoir in combination with an oil-gas two-phase flow energy production equation considering stress sensitivity. The method can accurately predict the productivity in different periods of the oil-gas two-phase flow stage of the condensate gas reservoir, and has very important effect and significance for guiding the development of the condensate gas reservoir.

Description

Technical Field

[0001] The present invention relates to the technical field of oil and gas field development, and particularly to a method for predicting the productivity of oil and gas two-phase flow in condensate gas wells considering stress sensitivity. Background Technique

[0002] Condensate gas reservoirs are a special type of oil and gas reservoirs, widely distributed in oil and gas basins around the world. Due to their high economic value, they have gradually become important exploration and development targets and growth points for oil and gas reserves. During the development of condensate gas reservoirs, as the production time increases, the formation pressure continuously decreases. When the bottom-hole pressure (p wf ) is lower than the dew-point pressure (p d ), condensate oil begins to precipitate. When the oil saturation (S o ) in the formation exceeds the critical flow saturation (S m ), the condensate oil begins to flow. First, oil and gas two-phase seepage forms in the near-wellbore area. As the formation pressure further decreases, the oil and gas two-phase seepage area continuously expands and extends towards the boundary. In the early stage of oil and gas two-phase flow, only condensate oil precipitates in the near-wellbore area, and there is oil and gas two-phase flow, while no condensate oil precipitates in the far-wellbore area, which is single-phase gas flow; in the middle stage of oil and gas two-phase flow, condensate oil precipitates in the far-wellbore area, but the oil saturation is lower than the critical flow saturation, and the condensate oil does not participate in the flow; in the late stage of oil and gas two-phase flow, oil and gas two-phase flow appears throughout the gas reservoir.

[0003] Currently, the productivity evaluation method for oil and gas two-phase flow in condensate gas reservoirs mainly uses the two-phase pseudo-pressure method, regarding the condensate gas reservoir as an overall two-phase flow, without dividing the seepage area according to the seepage characteristics of oil and gas two-phase flow in different periods, resulting in a deviation between the calculated productivity result and the production reality. Therefore, conducting research on the productivity equation of oil and gas two-phase flow in condensate gas reservoirs by period and region is of great importance for accurately predicting the productivity of condensate gas wells. Summary of the Invention

[0004] Aiming at the above problems, the present invention aims to provide a method for predicting the productivity of oil and gas two-phase flow in condensate gas wells considering stress sensitivity.

[0005] The technical solution of the present invention is as follows:

[0006] A method for predicting the productivity of oil and gas two-phase flow in condensate gas wells considering stress sensitivity, comprising the following steps:

[0007] S1: Divide the oil and gas two-phase seepage stage of the condensate gas reservoir into three seepage periods: early, middle, and late, and establish a seepage physical model for each seepage period;

[0008] S2: Based on the seepage physical model, establish a pseudo-pressure function considering stress sensitivity for each seepage period, and establish an oil and gas two-phase flow productivity equation considering stress sensitivity based on the seepage physical model;

[0009] S3: Determine the seepage period of the oil-gas two-phase seepage in the target condensate gas reservoir, and select the pseudo-pressure function corresponding to the seepage period according to the determination result to calculate its pseudo-pressure;

[0010] S4: Predict the productivity of the target condensate gas reservoir based on the calculation result of the pseudo-pressure of the oil-gas two-phase seepage in the target condensate gas reservoir and in combination with the productivity equation of the oil-gas two-phase flow considering stress sensitivity.

[0011] Preferably, in step S1, in each seepage period, according to the bottom-hole flowing pressure p wf , the critical flowing pressure p m of condensate oil, the dew-point pressure p d , and the boundary pressure p e for division:

[0012] When p wf < p m < p d < p e , the corresponding oil-gas two-phase seepage stage of the condensate gas reservoir is divided into the early stage;

[0013] When p wf < p m < p e < p d , the corresponding oil-gas two-phase seepage stage of the condensate gas reservoir is divided into the middle stage;

[0014] When p wf < p e < p m < p d , the corresponding oil-gas two-phase seepage stage of the condensate gas reservoir is divided into the early stage.

[0015] Preferably, in step S1, when establishing the seepage physical model for each seepage period, the seepage physical model in the early stage includes Region I, Region II, and Region III, the seepage physical model in the middle stage includes Region I and Region II, and the seepage physical model in the late stage includes Region I;

[0016] The said Region I is the oil-gas two-phase seepage area, and the condensate oil saturation S o in the oil-gas two-phase seepage area is greater than the critical flowing saturation S or of condensate oil;

[0017] The said Region II is the single-phase gas flow area I, and the condensate oil saturation S o in the single-phase gas flow area I is less than the critical flowing saturation S or of condensate oil;

[0018] The said Region III is the single-phase gas flow area II, and the condensate oil saturation S oEqual to the critical flow saturation S of condensate oil or .

[0019] Preferably, in step S2, the pseudo-pressure function considering stress sensitivity in the early stage is:[[]]

[0020]

[0021] The pseudo-pressure function considering stress sensitivity in the middle stage is:[[]]

[0022]

[0023] The pseudo-pressure function considering stress sensitivity in the late stage is:[[]]

[0024]

[0025] In the formula: f(p) is the pseudo-pressure function; k ro is the relative permeability of the oil phase, dimensionless; ρ o is the density of the oil phase, kg / m 3 ; μ o is the viscosity of the oil phase, mPa·s; k rg is the relative permeability of the gas phase, dimensionless; ρ g is the density of the gas phase, kg / m 3 ; μ g is the viscosity of the gas phase, mPa·s; α is the rock stress sensitivity coefficient, MPa -1 ; p i is the original formation pressure, MPa; p is the pressure at any point in the formation, MPa; p m is the critical flow pressure of condensate oil, MPa; p d is the dew point pressure, MPa; k rg (s wi ) is the relative permeability of the gas phase under the condition of irreducible water saturation s wi , dimensionless; p e is the boundary pressure, MPa.[[]]

[0026] Preferably, in step S2, the productivity equation of the oil-gas two-phase flow considering stress sensitivity is:[[]]

[0027] ψ(p e ) - ψ(p wf ) = Aq gsc + Bq gsc 2 (4)[[]]

[0028]

[0029] In the formula: Ψ(p e ) is the boundary pressure p ePseudo-pressure of oil-gas two-phase under certain conditions, kg / m 3 / (mPa·s); Ψ(p wf ) is the bottom-hole flowing pressure p wf Pseudo-pressure of oil-gas two-phase under certain conditions, kg / m 3 / (mPa·s); Both A and B are intermediate parameters; q gsc is the gas-phase volume flow rate under standard conditions, m 3 / d; Ψ(p) is the pseudo-pressure of oil-gas two-phase, kg / m 3 / (mPa·s); γ o is the relative density of condensate oil, dimensionless; R og is the production gas-oil ratio, m 3 / m 3 ; ρ gsc is the density of gas phase under standard conditions, kg / m 3 ; k i is the permeability under the original formation pressure, μm 2 ; h is the effective thickness of the reservoir, m; r e is the boundary radius, m; r wf is the wellbore radius, m; β g is the turbulence coefficient of natural gas, dimensionless; L g is the ratio of the mass flow rate of gas in the formation to the total mass flow rate, dimensionless; r is the formation radius, m.

[0030] The beneficial effects of the present invention are as follows:

[0031] According to the seepage characteristics of oil-gas two-phase flow in different stages of condensate gas reservoirs, the present invention divides them into different seepage periods, then establishes the corresponding pseudo-pressure function for each different seepage period, and establishes the productivity equation of oil-gas two-phase flow considering stress sensitivity. In this way, it can more accurately predict the productivity of oil-gas two-phase flow in condensate gas wells, which has very important functions and significance for guiding the development of condensate gas reservoirs. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0033] Figure 1 is the schematic diagram of the relative permeability curve of oil-gas two-phase flow in the condensate gas reservoir of the present invention;

[0034] Figure 2 is the schematic diagram of the multi-region physical model of oil-gas two-phase flow in the condensate gas reservoir of the present invention;

[0035] Figure 3 It is a schematic diagram of IPR curves of three seepage periods of oil-gas two-phase flow in a condensate gas reservoir in a specific embodiment. DETAILED DESCRIPTION

[0036] The present invention is further described below in conjunction with the accompanying drawings and embodiments. It should be noted that, in the absence of conflict, the embodiments in this application and the technical features in the embodiments can be combined with each other. It should be noted that, unless otherwise specified, all technical and scientific terms used in this application have the same meanings as those generally understood by those of ordinary skill in the art to which this application belongs. The words "including" or "comprising" and the like used in the disclosure of the present invention mean that the elements or objects appearing before the word cover the elements or objects listed after the word and their equivalents, without excluding other elements or objects.

[0037] The present invention provides a method for predicting the productivity of oil and gas two-phase flow in a condensate gas well considering stress sensitivity, comprising the following steps:

[0038] S1: The oil-gas two-phase seepage stage of condensate gas reservoir is divided into three seepage periods: early, middle and late, and the seepage physical model of each seepage period is established.

[0039] In a specific embodiment, each seepage period is based on the bottom hole flow pressure p wf , condensate critical flow pressure p m , dew point pressure p d and the boundary pressure p e To divide:

[0040] When p wf <p m <p d <p e When , the corresponding oil-gas two-phase seepage stage of condensate gas reservoir is divided into early stage;

[0041] When p wf <p m <p e <p d When , the corresponding oil-gas two-phase seepage stage of condensate gas reservoir is divided into the middle stage;

[0042] When p wf <p e <p m <p d When , the corresponding oil-gas two-phase seepage stage of condensate gas reservoir is divided into early stage.

[0043] In the above embodiment, each divided seepage period has the following characteristics:

[0044] (1) Early stage: Condensate oil precipitates only in the near - wellbore area, and there is an oil - gas two - phase flow; no condensate oil precipitates in the far - wellbore area, and it is a single - phase gas flow.

[0045] (2) Middle stage: The near - wellbore area is an oil - gas two - phase flow; condensate oil precipitates in the far - wellbore area, but the oil saturation is lower than the critical flow saturation, and the condensate oil does not participate in the flow.

[0046] (3) Late stage: An oil - gas two - phase flow appears throughout the gas reservoir.

[0047] In a specific embodiment, as Figure 1-2 shown, when establishing the seepage physical models for each seepage period, the early - stage seepage physical model includes Region I, Region II, and Region III, the middle - stage seepage physical model includes Region I and Region II, and the late - stage seepage physical model includes Region I;

[0048] The said Region I is an oil - gas two - phase seepage area, and the condensate oil saturation S o in the oil - gas two - phase seepage area is greater than the critical flow saturation S or ;

[0049] The said Region II is a single - phase gas flow area I, and the condensate oil saturation S o in the single - phase gas flow area I is less than the critical flow saturation S or ;

[0050] The said Region III is a single - phase gas flow area II, and the condensate oil saturation S o in the single - phase gas flow area II is equal to the critical flow saturation S or .

[0051] In the above - mentioned embodiment, the single - phase gas flow area I is a single - phase gas flow area where condensate oil precipitates but does not flow, and the single - phase gas flow area II is a single - phase gas flow area where no condensate oil precipitates.

[0052] S2: Based on the seepage physical model, establish the pseudo - pressure function considering stress sensitivity for each seepage period, and establish the productivity equation of oil - gas two - phase flow considering stress sensitivity based on the seepage physical model.

[0053] In a specific embodiment, the pseudo - pressure function considering stress sensitivity in the early stage is:

[0054]

[0055] The pseudo - pressure function considering stress sensitivity in the middle stage is:

[0056]

[0057] The pseudo - pressure function considering stress sensitivity in the late stage is:

[0058]

[0059] In the formula: f(p) is the pseudo-pressure function; k ro is the relative permeability of the oil phase, dimensionless; ρ o is the density of the oil phase, kg / m 3 ; μ o is the viscosity of the oil phase, mPa·s; k rg is the relative permeability of the gas phase, dimensionless; ρ g is the density of the gas phase, kg / m 3 ; μ g is the viscosity of the gas phase, mPa·s; α is the rock stress sensitivity coefficient, MPa -1 ; p i is the original formation pressure, MPa; p is the pressure at any point in the formation, MPa; p m is the critical flow pressure of the condensate oil, MPa; p d is the dew point pressure, MPa; k rg (s wi ) is the relative permeability of the gas phase under the condition of irreducible water saturation s wi ; p e is the boundary pressure, MPa.

[0060] In a specific embodiment, the productivity equation of the oil-gas two-phase flow considering stress sensitivity is:

[0061] ψ(p e ) - ψ(p wf ) = Aq gsc + Bq gsc 2 (4)

[0062]

[0063] In the formula: Ψ(p e ) is the pseudo-pressure of the oil-gas two-phase flow under the boundary pressure p e condition, kg / m 3 / (mPa·s); Ψ(p wf ) is the pseudo-pressure of the oil-gas two-phase flow under the bottom-hole flowing pressure p wf condition, kg / m 3 / (mPa·s); A and B are both intermediate parameters; q gsc is the gas-phase volume flow rate under standard conditions, m 3 / d; Ψ(p) is the pseudo-pressure of the oil-gas two-phase flow, kg / m 3 / (mPa·s); γ o is the relative density of the condensate oil, dimensionless; R og is the produced oil-gas ratio, m 3 / m3 ; ρ gsc is the density of the gas phase under standard conditions, kg / m 3 ; k i is the permeability under the original formation pressure, μm 2 ; h is the effective thickness of the reservoir, m; r e is the boundary radius, m; r wf is the wellbore radius, m; β g is the turbulence coefficient of natural gas, dimensionless; L g is the ratio of the mass flow rate of gas in the formation to the total mass flow rate, dimensionless; r is the formation radius, m.

[0064] In the above embodiment, the oil-gas two-phase production capacity equation considering stress sensitivity is obtained through the following steps:

[0065] Considering the stress sensitivity effect, the gas reservoir permeability and the effective stress usually show an exponential relationship

[18] :

[0066]

[0067] In the formula: k is the reservoir permeability, μm 2 ;

[0068] In the process of oil-gas two-phase flow in a condensate gas reservoir, it is assumed that the oil phase obeys Darcy's seepage law, the gas phase obeys non-Darcy's seepage law, and the formation water is in the bound water condition and does not participate in the flow. Based on the oil-gas mass flow rate under formation conditions, the oil-gas two-phase motion equation considering stress sensitivity can be derived:

[0069]

[0070] In the formula: p o is the formation pressure of the oil phase, MPa; Q o is the mass flow rate of the oil phase, kg / s; p g is the formation pressure of the gas phase, MPa; Q g is the mass flow rate of the gas phase, kg / s;

[0071] In formula (10), the turbulence coefficient of the natural gas can be calculated by the following empirical formula:

[0072]

[0073] In the formula: φ is the porosity of the gas reservoir, dimensionless;

[0074] After adding formula (9) and formula (10) and separating variables, we get:

[0075]

[0076] According to the stage of the oil-gas two-phase flow in the formation, determine the pseudo-pressure function f(p), and define the oil-gas two-phase pseudo-pressure ψ(p) as shown in Equation (5):

[0077] Substitute Equation (5) into Equation (12) and integrate both sides of the equation to obtain:

[0078]

[0079] Total mass flow rate of oil-gas two-phase:

[0080] Q t = Q o + Q g (14)

[0081] In the formula: Q t is the total mass flow rate of oil-gas two-phase, kg / s;

[0082] According to the law of conservation of mass, convert the underground oil-gas flow rate to the flow rate under standard surface conditions:

[0083] Q t = q o ρ o + q g ρ g = q osc ρ osc + q gsc ρ gsc (15)

[0084] In the formula: q o is the oil-phase volume flow rate under formation conditions, m 3 / d; q g is the gas-phase volume flow rate under formation conditions, m 3 / d; q osc is the oil-phase volume flow rate under standard conditions, m 3 / d; ρ osc is the oil-phase density under standard conditions, kg / m 3 ;

[0085] Convert the condensate oil under standard conditions into condensate gas:

[0086] Q t = (q gsc + q osc ·5.43×10 2 (1.03 - γ o ))·ρ gsc (16)

[0087] Define L g as the ratio of the mass flow rate of gas in the formation to the total mass flow rate:

[0088]

[0089] In the formula: M g is the mass fraction of the gas phase in the formation, dimensionless; M o is the mass fraction of the oil phase in the formation, dimensionless;

[0090] The production oil-gas ratio under standard conditions:

[0091] R og = q osc / q gsc (18)

[0092] Substitute equations (16)-(18) into equation (13) to obtain the productivity equation for oil-gas two-phase flow:

[0093]

[0094] Simplify equation (19) to equation (4), and the intermediate parameters A and B in equation (4) are shown in equations (6) and (7) respectively. In summary, the productivity equation for oil-gas two-phase flow considering stress sensitivity shown in equations (4)-(7) is obtained.

[0095] S3: Determine the seepage period of oil-gas two-phase seepage in the target condensate gas reservoir, and select the pseudo-pressure function corresponding to the seepage period according to the determination result to calculate its pseudo-pressure.

[0096] In a specific embodiment, when calculating the pseudo-pressure, the key to the solution is to calculate the relationship between each parameter and the pressure. The relationship between the relative permeability and the pressure can first determine the relationship between k ro / k rg ~ p according to the steady-state theory, and then determine k ro , k rg at different pressures according to the relationship between the relative permeability curve and the oil saturation.

[0097]

[0098] In the formula: L is the mole fraction of condensate oil, dimensionless; V is the mole fraction of condensate gas, dimensionless.

[0099] ρ g , ρ o , μ o , μ g , L, and V at different pressures can be obtained according to phase flash calculation and the equation of state.

[0100] Obtain the relationship between the two-phase pseudo-pressure Ψ(p)~p through numerical integration, and use the interpolation method to calculate the two-phase pseudo-pressure at the measured pressure.

[0101]

[0102] The relationships between the parameters in the non-Darcy coefficient and pressure have been obtained through phase flash calculations. Based on the steady-state seepage theory, calculating the relationship between formation pressure and radius, the values of k rg , μ g , β g , L g and the radius r can be obtained, and then the non-Darcy coefficient under the measured pressure can be obtained through numerical integration.

[0103]

[0104] Where: r wf' is the effective wellbore radius, m.

[0105] S4: According to the calculated results of the pseudo-pressure of the oil-gas two-phase flow in the target condensate gas reservoir, combined with the productivity equation of the oil-gas two-phase flow considering stress sensitivity, predict its productivity.

[0106] In a specific embodiment, taking a condensate gas reservoir as an example, the productivity prediction method for the oil-gas two-phase flow of the condensate gas well considering stress sensitivity described in the present invention is used to predict the productivity of the oil-gas two-phase flow of the condensate gas well.

[0107] In this embodiment, the original formation pressure of the condensate gas reservoir is 47.23 MPa, the dew point pressure is 41.68 MPa, and the critical flow pressure of the condensate oil is 35.74 MPa. The oil-gas two-phase fluid parameters under different formation pressures are shown in Table 1:

[0108] Table 1 Oil-gas two-phase fluid parameter table under different formation pressures

[0109]

[0110]

[0111] When the bottom-hole flowing pressure is lower than 35.74 MPa, the formation enters the oil-gas two-phase flow stage. At this time, according to the magnitude relationship between the formation pressure, the dew point pressure, and the critical flow pressure of the condensate oil, three points with formation pressures of p e1 = 47.23 MPa; p e2 = 41.6 MPa; p e3 = 33.6 MPa are selected, corresponding to the early stage (3-region model), middle stage (2-region model), and late stage (single-region model) of the oil-gas two-phase flow respectively. Select the corresponding pseudo-pressure function to calculate its pseudo-pressure, and combined with the productivity equation of the oil-gas two-phase flow considering stress sensitivity, calculate the open flow rates in the early, middle, and late different two-phase flow periods respectively. The typical IPR curves under the conditions of the 3-region models are as Figure 3 shown.

[0112] From Figure 3It can be seen that at the same bottom-hole flowing pressure, the gas well production of the three-region model is the largest, followed by the two-region model, and the single-region model is the smallest. From the three-region model to the single-region model, the IPR curve moves to the lower left, the absolute open flow potential decreases, and the curve becomes steeper, with the absolute value of the curve slope increasing. This is because as the formation pressure decreases, condensate oil precipitates in the near-wellbore area and blocks the throat, and the single-phase gas flow changes to a two-phase oil-gas flow, resulting in a decrease in the relative permeability of the gas phase and an enhancement of the high-speed non-Darcy effect, which increases the coefficient B of the productivity equation and makes the IPR curve steeper.

[0113] In summary, according to the seepage characteristics of the two-phase oil-gas flow in different periods, the present invention conducts research on the productivity equation of the two-phase oil-gas flow in condensate gas reservoirs in different regions, and can more accurately predict the productivity of condensate gas wells. Compared with the prior art, the present invention has made significant progress.

[0114] The above are only the preferred embodiments of the present invention, and do not impose any form of limitation on the present invention. Although the present invention has been disclosed above with the preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some changes or modifications to the above-disclosed technical content to obtain equivalent embodiments with equivalent changes, but as long as the content does not depart from the technical solution of the present invention, any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A method for predicting the productivity of oil-gas two-phase flow in a condensate gas well considering stress sensitivity, characterized in that It includes the following steps: S1: Divide the oil-gas two-phase seepage stage of the condensate gas reservoir into three seepage periods: early, middle, and late, and establish a seepage physical model for each seepage period; S2: Based on the seepage physical model, establish a pseudo-pressure function considering stress sensitivity for each seepage period, and based on the seepage physical model, establish a productivity equation for oil-gas two-phase flow considering stress sensitivity; S3: Determine the seepage period in which the oil-gas two-phase seepage of the target condensate gas reservoir is located, and select the pseudo-pressure function of the corresponding seepage period according to the determination result to calculate its pseudo-pressure; S4: According to the calculation result of the pseudo-pressure of the oil-gas two-phase seepage of the target condensate gas reservoir, combine the productivity equation of the oil-gas two-phase flow considering stress sensitivity to predict its productivity.

2. The method for predicting the productivity of oil-gas two-phase flow in a condensate gas well considering stress sensitivity according to claim 1, wherein In step S1, each seepage period is divided according to the bottom-hole flowing pressure p wf , the critical flowing pressure p m of condensate oil, the dew-point pressure p d , and the boundary pressure p e : When p wf <p m <p d <p e , the corresponding oil-gas two-phase seepage stage of the condensate gas reservoir is divided into the early stage; When p wf <p m <p e <p d , the corresponding two-phase seepage stage of the condensate gas reservoir is divided into the middle stage; When p wf <p e <p m <p d When this occurs, the two-phase oil and gas seepage stage of the corresponding condensate gas reservoir is divided into the early stage.

3. The method for predicting the productivity of oil-gas two-phase flow in a condensate gas well considering stress sensitivity according to claim 1, wherein In step S1, when establishing the seepage physical model for each seepage period, the early seepage physical model includes Region I, Region II, and Region III, the middle seepage physical model includes Region I and Region II, and the late seepage physical model includes Region I; The area I is an oil-gas two-phase seepage area, and the condensate oil saturation S in the oil-gas two-phase seepage area o is greater than the critical flow saturation S of the condensate oil or ; The said Region II is a single-phase gas flow region I, and the condensate oil saturation S of the single-phase gas flow region I o is less than the critical flow saturation S of the condensate oil or ; Said Region III is the two-phase gas flow zone, and the condensate oil saturation S o in the two-phase gas flow zone is equal to the critical flowing saturation S or of the condensate oil.

4. The method for predicting the productivity of oil-gas two-phase flow in a condensate gas well considering stress sensitivity according to claim 3, characterized in that, In step S2, the pseudo-pressure function considering stress sensitivity in the early stage is: The pseudo-pressure function considering stress sensitivity in the middle stage is: The pseudo-pressure function considering stress sensitivity in the late stage is: where: f(p) is the pseudo-pressure function; k ro is the relative permeability of the oil phase, dimensionless; ρ o is the density of the oil phase, kg / m 3 ; μ o is the viscosity of the oil phase, mPa·s; k rg is the relative permeability of the gas phase, dimensionless; ρ g is the density of the gas phase, kg / m 3 ; μ g is the viscosity of the gas phase, mPa·s; α is the rock stress sensitivity coefficient, MPa -1 ; p i is the original formation pressure, MPa; p is the pressure at any point in the formation, MPa; p m is the critical flow pressure of condensate oil, MPa; p d is the dew point pressure, MPa; k rg (s wi ) is the irreducible water saturation s wi under the condition of the relative permeability of the gas phase, dimensionless; p e is the boundary pressure, MPa.

5. The method for predicting the productivity of oil-gas two-phase flow in a condensate gas well considering stress sensitivity according to claim 4, wherein In step S2, the productivity equation of the oil-gas two-phase flow considering stress sensitivity is: ψ(p e ) - ψ(p wf ) = Aq gsc + Bq gsc 2 (4) Where: Ψ(p e ) is the pseudo-pressure of the oil-gas two-phase under the boundary pressure p e , kg / m 3 / (mPa·s); Ψ(p wf ) is the pseudo-pressure of the oil-gas two-phase under the bottom-hole flowing pressure p wf , kg / m 3 / (mPa·s); Both A and B are intermediate parameters; q gsc is the gas-phase volume flow rate under standard conditions, m 3 / d; Ψ(p) is the pseudo-pressure of the oil-gas two-phase, kg / m 3 / (mPa·s); γ o is the relative density of the condensate oil, dimensionless; R og For the production gas-oil ratio, m 3 / m 3 ; ρ gsc is the density of the gas phase under standard conditions, kg / m 3 ; k i is the permeability under the original formation pressure, μm 2 ; h is the effective thickness of the reservoir, m; r e is the boundary radius, m; r wf is the wellbore radius, m; β g is the turbulence coefficient of natural gas, dimensionless; L g is the ratio of the mass flow rate of gas in the formation to the total mass flow rate, dimensionless; r is the formation radius, m.

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