Parameter evaluation method and equipment for gas well in compact reservoir based on stress sensitivity effect

Abstract

This invention discloses a method and equipment for evaluating tight reservoir gas well parameters based on stress sensitivity, including: acquiring actual production data of the gas well; determining the reservoir stress sensitivity coefficient; obtaining a normalized production-mass balance pseudo-time curve, a normalized production integral-mass balance pseudo-time curve, and a normalized production integral derivative-mass balance pseudo-time curve considering stress sensitivity; fitting the above three curves to a typical curve chart for production instability analysis to determine the time shift, production shift, and position number; obtaining the dynamic reserves of the first gas well and the second gas well; using the average of the dynamic reserves of the first and second gas wells as the dynamic reserves of the gas well under the mutual constraint of the flow mass balance method and the chart fitting method; and calculating reservoir parameters and fracture parameters. This invention enables accurate evaluation of parameters such as dynamic reserves of gas wells in low-permeability tight gas reservoirs, and can conveniently, quickly, accurately, and effectively evaluate gas well parameters and reservoir parameters.

Description

Technical Field

[0001] This invention belongs to the field of dynamic evaluation technology for gas wells, specifically relating to a method and electronic equipment for evaluating parameters of tight reservoir gas wells based on stress-sensitive influence. Background Technology

[0002] As oil and gas fields gradually expand into unconventional gas reservoirs, research on tight, low-permeability gas reservoirs is increasing. In these reservoirs, the tightness of the reservoir and water-bearing capacity during well production cause stress sensitivity during gas flow; that is, reservoir permeability gradually decreases as formation pressure decreases. For developing such tight, low-permeability gas reservoirs, using conventional well production decline analysis methods for parameter evaluation will result in significant errors. Therefore, research on quantitative evaluation methods for well parameters and reservoir parameters in low-permeability tight reservoirs, considering the effects of stress sensitivity, is of great significance for developing these reservoirs. Currently, commonly used well production decline analysis methods include the Flow Mass Balance (FMB) method and the chart fitting method, which are dynamic evaluation methods for conventional gas reservoir wells. If the influence of stress sensitivity is ignored, using these commonly studied conventional well production decline analysis methods will result in inaccurate dynamic reserves and reservoir permeability parameters obtained through fitting, which will seriously affect the evaluation of reservoir utilization and the selection of favorable areas. This will further affect the rational development deployment of well locations and networks, as well as the study of remaining gas distribution.

[0003] Most modern production decline analysis techniques are used under Darcy flow conditions for conventional high-permeability reservoirs to estimate reservoir and well parameters such as permeability, vent radius, skin factor, and fracture half-length. For conventional gas wells, production instability analysis methods have been extensively studied.

[0004] The Fetkovich method, based on unsteady flow in homogeneous closed reservoirs, introduces the Arps decreasing curve into the flow formula for unsteady flow during well testing. This curve then includes both the unsteady and quasi-steady flow stages, visually representing the radial and boundary-controlled flow stages, thus forming the Fetkovich production instability analysis fitting chart. However, this method does not consider the variation of fluid properties with pressure. Blasingame et al. introduced material equilibrium time and regularized production parameters into the flow equation, establishing the Blasingame production instability analysis fitting chart. This method also considers varying bottomhole pressure and production rates, as well as the variation of fluid properties with pressure. Agarwal-Gardner et al., building on previous research, redefined dimensionless variables and established the Agarwal-Gardner production instability analysis fitting chart. The unsteady flow stage curves in this chart are relatively more dispersed than those in the Blasingame chart. This helps reduce the ambiguity of fitting analysis. The Flow Material Balance (FMB) method derives a detailed representation of the pseudo-time of material balance and uses production dynamic data for analysis and fitting. Through linear regression, the original geological reserves of oil and gas reservoirs can be estimated. However, this method requires production data to reach the pseudo-steady-state flow stage. The Blasingame method and the Agarwal-Gardner method both use pseudo-pressure normalized production and material balance pseudo-time functions to establish typical declining curves. The Normalized Pressure Integral (NPI) method uses the integral form of production normalized pressure and material balance pseudo-time to construct a curve. The NPI curve fitting method is the reciprocal of the Agarwal-Gardner production instability analysis curve. The NPI method can also handle variable production and variable flowing pressure problems and use daily production data (time, production, flowing pressure) to evaluate reservoir parameters. For data in the unstable flow stage, the transient method based on the dimensionless time and production relationship of well testing can be used for fitting analysis to reduce the ambiguity of the analysis results.

[0005] Current methods for evaluating the dynamic reserves of gas wells that consider stress sensitivity, such as those used to assess parameters like dynamic reserves in tight, low-permeability reservoirs, are based on the principle of mass balance and incorporate stress sensitivity considerations. p / Z - G p The relationship curve is used to determine the dynamic reserves of the gas well based on the linear relationship, but it is not possible to obtain other reservoir parameters and gas well parameters.

[0006] In summary, the main shortcomings of existing conventional gas well production decline analysis methods for evaluating parameters such as dynamic reserves of gas wells are as follows:

[0007] (1) Modern production decline analysis and evaluation method for conventional gas reservoirs: Production decline analysis can only be performed on gas wells in high-permeability single-phase conventional reservoirs. For low-permeability tight reservoirs, the evaluation parameters have certain errors, which will underestimate the dynamic reserves of gas wells and reservoir permeability, and incorrectly judge the utilization status of gas reservoir reserves and the distribution of unutilized reserves, thus affecting the subsequent tapping of remaining gas potential.

[0008] (2) Among the evaluation methods for dynamic reserves that consider the effects of stress sensitivity, the modified method is currently the most widely used. p / Z - G p The method can only obtain dynamic reserve parameters of gas wells, but cannot determine other reservoir parameters, gas well parameters, and fracture parameters such as reservoir permeability and fracture half-length. In addition, the method is relatively simple and linear, resulting in large errors in the evaluation parameters.

[0009] Therefore, there is a particular need to provide a quantitative analysis and evaluation method for gas well parameters such as dynamic reserves that takes into account the effects of stress sensitivity. Summary of the Invention

[0010] The purpose of this invention is to propose a quantitative analysis and evaluation method for gas well parameters such as dynamic reserves that takes into account the influence of stress sensitivity.

[0011] This invention provides a method for evaluating parameters of tight reservoir gas wells based on stress sensitivity, comprising: acquiring actual production data of the gas well; determining the reservoir stress sensitivity coefficient; calculating the material balance pseudo-time based on the actual production data; calculating the original pseudo-pressure and pseudo-bottomhole flow pressure of the gas well considering the stress sensitivity effect based on the actual production data and the reservoir stress sensitivity coefficient; further calculating the normalized production, normalized production integral, and normalized production integral derivative considering the stress sensitivity effect; and obtaining the normalized production-material balance pseudo-time curve, normalized production integral-material balance pseudo-time curve, and normalized production integral derivative-material balance pseudo-time curve considering the stress sensitivity effect. The normalized production-mass balance pseudo-time curve, normalized production integral-mass balance pseudo-time curve, and normalized production integral derivative-mass balance pseudo-time curve considering stress sensitivity effects are respectively fitted to the typical curve chart of production instability analysis to determine the time shift, production shift, and number of locations. Based on the time shift, the dynamic reserves of the first gas well are calculated. According to the flow mass balance equation, the dynamic reserves of the second gas well are obtained. The average value of the dynamic reserves of the first and second gas wells is taken as the dynamic reserves of the gas well under the mutual constraint of the flow mass balance method and the chart fitting method. Based on the production shift and number of locations, reservoir parameters and fracture parameters are calculated.

[0012] Optionally, the typical curve chart for yield instability analysis includes multiple sets of preset curves. Each set of preset curves includes a preset dimensionless normalized yield-material balance pseudo-time curve, a preset dimensionless normalized yield integral-material balance pseudo-time curve, and a preset dimensionless normalized yield integral derivative-material balance pseudo-time curve.

[0013] Optionally, the step of fitting the normalized production-material balance pseudo-time curve, normalized production integral-material balance pseudo-time curve, and normalized production integral derivative-material balance pseudo-time curve considering stress sensitivity effects to the typical curve chart for production instability analysis to determine the time shift, production shift, and number of positions includes: plotting the normalized production-material balance pseudo-time curve, normalized production integral-material balance pseudo-time curve, and normalized production integral derivative-material balance pseudo-time curve considering stress sensitivity effects on the typical curve chart for production instability analysis; taking any point in the normalized production-material balance pseudo-time curve, normalized production integral-material balance pseudo-time curve, or normalized production integral derivative-material balance pseudo-time curve considering stress sensitivity effects as a marker point, and obtaining the initial position of the marker point; in the typical curve chart for production instability analysis... In the curve chart, the normalized production-material balance pseudo-time curve, normalized production integral-material balance pseudo-time curve, and normalized production integral derivative-material balance pseudo-time curve considering stress sensitivity are moved along the horizontal and vertical axes until they coincide with the preset dimensionless normalized production-material balance pseudo-time curve, preset dimensionless normalized production integral-material balance pseudo-time curve, and preset dimensionless normalized production integral derivative-material balance pseudo-time curve in the same set of preset curves; the final position of the marker point is obtained; based on the initial and final positions, the time shift and production shift are calculated; the number of sets of overlapping preset curves is taken as the position number.

[0014] Optionally, the time shift k can be calculated using the following formula. s :

[0015]

[0016] The production movement k is calculated using the following formula. q :

[0017]

[0018] in, t αdThe time at the initial position is also the pseudo-time of the mass equilibrium at the marked point. The dimensionless time for the final position is also the time it takes for the marker point to travel along the overlapping preset curve. q αd The output at the initial position is also the normalized output at the marked point. The dimensionless output of the final position is also the normalized output of the marker point in the overlapping preset curve.

[0019] Optionally, the actual production data includes: daily gas production. t Gas production rate at any given moment, production time t The original formation pressure and bottom hole flowing pressure of the reservoir.

[0020] Optionally, determining the magnitude of the reservoir stress sensitivity coefficient includes: analyzing the stress sensitivity experimental data of tight reservoir cores under different test pressures, and determining the reservoir stress sensitivity coefficient through multivariate statistical analysis.

[0021] Optionally, the equilibrium pseudo-time of the substance can be calculated using the following formula:

[0022]

[0023] The normalized yield, taking into account the effects of stress sensitivity, is calculated using the following formula:

[0024]

[0025] The normalized production integral considering stress sensitivity effects is calculated using the following formula:

[0026]

[0027] The normalized yield integral derivative considering stress sensitivity effects is calculated using the following formula:

[0028]

[0029] in, t αd To simulate time for material equilibrium, μ gi The original gas viscosity. μ g ( t )for t The gas viscosity at time t, C ti The overall compression coefficient under the original conditions. C t ( t () represents the overall compression coefficient at time t. q Daily gas productiont For production time, q αd To account for the stress-sensitive effects on the normalized production, To account for the stress-sensitive effect of the pseudo-pressure difference, To account for the original pseudo-pressure of the gas well in the case of stress sensitivity, To account for the stress-sensitive effects of the simulated bottom hole flow pressure, q αdi To account for the stress-sensitive effects of the normalized production integral, q αdid To account for the stress-sensitive effects of the normalized production integral derivative, the subscript is... i For integration, subscript id It is the integral derivative.

[0030] Optionally, the original pseudo-pressure of the gas well, taking into account the effects of stress sensitivity, can be calculated using the following formula:

[0031]

[0032] The pseudo-bottomhole flow pressure, taking into account stress-sensitive effects, is calculated using the following formula:

[0033]

[0034] in, p 0 represents any reference pressure, and can be taken as 0. p i The original formation pressure of the reservoir, p wf For bottom hole flowing pressure, μ g For gas viscosity, Z For gas deviation factor, α This is the stress sensitivity coefficient.

[0035] Optionally, the dynamic reserves of the first gas well can be calculated using the following formula:

[0036]

[0037] The dynamic reserves of the second gas well are calculated using the following formula:

[0038]

[0039] in,

[0040] in, G 1 represents the dynamic reserves of the first gas well. C t The overall compression coefficient is... q DdThe dimensionless yield of the marker point within the overlapping preset curve. G 2 represents the dynamic reserves of the second gas well. h For reservoir thickness, B The gas volume coefficient, A For the area of ​​air leakage, C A For shape factor, γ Let Euler's constant be 1. r w Where is the wellbore radius;

[0041] Reservoir parameters are calculated using the following formula:

[0042]

[0043]

[0044] Crack parameters are calculated using the following formula:

[0045]

[0046] in, k For penetration rate, r e For the vent radius, r eD The dimensionless vent radius is also a position number. x f For half the length of the crack, Porosity S w This represents the water saturation level.

[0047] The present invention also provides an electronic device, the electronic device comprising: a memory storing executable instructions; and a processor that executes the executable instructions in the memory to implement the above-described method for evaluating tight reservoir gas well parameters based on stress-sensitive effects.

[0048] The beneficial effects of this invention are as follows: The method for evaluating tight reservoir gas well parameters based on stress sensitivity of this invention establishes a modern production decline analysis method for low-permeability tight gas reservoirs that considers stress sensitivity. It enables accurate evaluation of parameters such as dynamic reserves of gas wells in low-permeability tight gas reservoirs, and can conveniently, quickly, accurately and effectively evaluate and obtain parameters of each gas well and reservoir, providing more data support and technical reference for reservoir utilization studies, residual gas distribution studies, favorable area selection, and implementation of subsequent production measures.

[0049] The present invention has other features and advantages that will be apparent from or will be set forth in detail in the accompanying drawings and following detailed description, which together serve to explain the particular principles of the invention. Attached Figure Description

[0050] The above and other objects, features and advantages of the present invention will become more apparent from the more detailed description of exemplary embodiments of the invention in conjunction with the accompanying drawings, wherein the same reference numerals generally represent the same components in the exemplary embodiments of the invention.

[0051] Figure 1 A flowchart of a method for evaluating parameters of tight reservoir gas wells based on stress-sensitive effects according to an embodiment of the present invention is shown.

[0052] Figure 2 The diagram shows the results of a plate fitting method considering the stress-sensitive effects of a tight reservoir gas well parameter evaluation method based on an embodiment of the present invention.

[0053] Figure 3 The diagram shows the results of a flow mass balance method considering the stress-sensitive effects of a tight reservoir gas well parameter evaluation method based on an embodiment of the present invention.

[0054] Figure 4 Actual gas well production data are shown for a method for evaluating tight reservoir gas well parameters based on stress-sensitive effects according to an embodiment of the present invention.

[0055] Figure 5 The bottomhole flowing pressure of a tight reservoir gas well based on a stress-sensitive effect evaluation method according to an embodiment of the present invention is shown.

[0056] Figure 6 The diagram shows a stress-sensitive fitting plot of a tight reservoir core according to an embodiment of the present invention, which is a method for evaluating tight reservoir gas well parameters based on stress-sensitive effects.

[0057] Figure 7 The diagram shows a gas well plot before fitting, according to an embodiment of the present invention, a method for evaluating tight reservoir gas well parameters based on stress-sensitive effects.

[0058] Figure 8 A schematic diagram of the well plate fitting results of a tight reservoir gas well parameter evaluation method based on stress-sensitive effects according to an embodiment of the present invention is shown.

[0059] Figure 9The diagram illustrates the well fitting results based on the flow mass balance equation for a tight reservoir gas well parameter evaluation method based on stress-sensitive effects according to an embodiment of the present invention. Detailed Implementation

[0060] Preferred embodiments of the invention will now be described in more detail. While preferred embodiments of the invention are described below, it should be understood that the invention can be implemented in various forms and should not be limited to the embodiments set forth herein.

[0061] This invention provides a method for evaluating parameters of tight reservoir gas wells based on stress sensitivity, comprising: acquiring actual production data of the gas well; determining the reservoir stress sensitivity coefficient; calculating the material balance pseudo-time based on the actual production data; calculating the original pseudo-pressure and pseudo-bottomhole flow pressure of the gas well considering the stress sensitivity effect based on the actual production data and the reservoir stress sensitivity coefficient; further calculating the normalized production, normalized production integral, and normalized production integral derivative considering the stress sensitivity effect; and obtaining the normalized production-material balance pseudo-time curve, normalized production integral-material balance pseudo-time curve, and normalized production integral derivative-material balance pseudo-time curve considering the stress sensitivity effect. The following steps are taken: The normalized production-mass balance pseudo-time curve, normalized production integral-mass balance pseudo-time curve, and normalized production integral derivative-mass balance pseudo-time curve considering stress sensitivity are fitted to typical curve charts for production instability analysis to determine the time shift, production shift, and number of locations. Based on the time shift, the dynamic reserves of the first gas well are calculated. According to the flow mass balance equation, the dynamic reserves of the second gas well are obtained. The average of the dynamic reserves of the first and second gas wells is taken as the dynamic reserves of the gas well under the mutual constraint of the flow mass balance method and the chart fitting method. Based on the production shift and number of locations, reservoir parameters and fracture parameters are calculated.

[0062] Specifically, based on a determined reservoir stress sensitivity coefficient, the normalized production rate that takes into account the influence of stress sensitivity can be calculated. q αd Regularized production integral q αdi Regularized product integral derivative q αdid and material balance pseudotime t αd The production time of each gas well will be obtained. q αd ~ t αd , q αdi ~ t αd , q αdid ~ tαd Three relationship curves are used to fit a typical curve chart for production instability analysis to obtain time shift, production shift, and location number. Finally, based on the time shift, production shift, location number, and corresponding formulas, the dynamic reserves, reservoir parameters, and fracture parameters of the first gas well are quantitatively obtained.

[0063] Based on the flow mass balance equation considering the stress-sensitive effects of the gas well, the dynamic reserves of the second gas well are determined. The flow mass balance method and the chart fitting method are mutually constrained to obtain the dynamic reserves of the gas well under the mutual constraint of the flow mass balance method and the chart fitting method.

[0064] According to an exemplary implementation, a method for evaluating tight reservoir gas well parameters based on stress sensitivity effects has been established. This method is a modern production decline analysis method for low-permeability tight gas reservoirs that considers stress sensitivity effects. It enables accurate evaluation of parameters such as dynamic reserves of gas wells in low-permeability tight gas reservoirs. It can conveniently, quickly, accurately and effectively evaluate and obtain parameters of each gas well and reservoir, providing more data support and technical reference for reservoir utilization studies, residual gas distribution studies, favorable area selection, and the implementation of subsequent production measures.

[0065] As an optional option, the typical curve chart for yield instability analysis includes multiple sets of preset curves. Each set of preset curves includes a preset dimensionless normalized yield-material balance pseudo-time curve, a preset dimensionless normalized yield integral-material balance pseudo-time curve, and a preset dimensionless normalized yield integral derivative-material balance pseudo-time curve.

[0066] Specifically, the typical curve chart for yield instability analysis includes multiple preset curves. Each preset curve includes a preset dimensionless normalized yield-material balance pseudo-time curve, a preset dimensionless normalized yield integral-material balance pseudo-time curve, and a preset dimensionless normalized yield integral derivative-material balance pseudo-time curve.

[0067] As an optional approach, the normalized production-mass balance pseudo-time curve, normalized production integral-mass balance pseudo-time curve, and normalized production integral derivative-mass balance pseudo-time curve considering stress sensitivity effects are respectively fitted to the typical curve chart for production instability analysis to determine the time shift, production shift, and number of positions. This includes: plotting the normalized production-mass balance pseudo-time curve, normalized production integral-mass balance pseudo-time curve, and normalized production integral derivative-mass balance pseudo-time curve considering stress sensitivity effects on the typical curve chart for production instability analysis; using any point in any of the normalized production-mass balance pseudo-time curve, normalized production integral-mass balance pseudo-time curve, or normalized production integral derivative-mass balance pseudo-time curve considering stress sensitivity effects as a marker point, and obtaining the initial position of the marker point; in the typical curve chart for production instability analysis... In the curve chart, the normalized production-material balance pseudo-time curve, normalized production integral-material balance pseudo-time curve, and normalized production integral derivative-material balance pseudo-time curve, which consider stress sensitivity effects, are moved along the horizontal and vertical axes until they coincide with the preset dimensionless normalized production-material balance pseudo-time curve, preset dimensionless normalized production integral-material balance pseudo-time curve, and preset dimensionless normalized production integral derivative-material balance pseudo-time curve in the same set of preset curves. The final position of the marker point is obtained. Based on the initial and final positions, the time shift and production shift are calculated. The number of sets of preset curves that coincide is taken as the position number.

[0068] Specifically, based on core experiments in tight reservoirs, the stress sensitivity coefficient is determined through statistical regression analysis of the core stress sensitivity test data. Combining this coefficient with the relevant formulas, the material balance pseudo-time, normalized production, normalized production integral, normalized production integral derivative, and normalized cumulative gas production of actual gas well production data considering stress sensitivity effects are calculated. The relationship curves between the normalized production, normalized production integral, and normalized production integral derivative of actual gas wells considering stress sensitivity effects and the material balance pseudo-time are plotted. These three normalized relationship curves considering stress sensitivity effects are then used to fit a typical curve chart for conventional production instability analysis of the corresponding well type. The three curves are plotted on the typical curve chart for production instability analysis and moved along the horizontal and vertical axes until they finally coincide with the preset curves on the chart. Any point on one of the three curves is selected as a marker, and the initial and final fitted positions are recorded to obtain the movement amount and the final fitted value. r eD The movement volume includes time movement volume and output value movement volume.

[0069] As an alternative, the time shift k can be calculated using the following formula. s :

[0070]

[0071] The production movement k is calculated using the following formula. q :

[0072]

[0073] in, t αd The time at the initial position is also the pseudo-time of the mass equilibrium at the marked point. The dimensionless time for the final position is also the dimensionless time for the marker point to lie on the pre-defined curve. q αd The output at the initial position is also the normalized output at the marked point. The dimensionless output at the final position is also the dimensionless normalized output of the marker point in the pre-defined curve that coincides with the position.

[0074] As an optional option, actual production data includes: daily gas production. t Gas production rate at any given moment, production time t The original formation pressure and bottom hole flowing pressure of the reservoir.

[0075] As an optional approach, determining the reservoir stress sensitivity coefficient includes: analyzing experimental data on the stress sensitivity of tight reservoir cores under different test pressures, and then determining the reservoir stress sensitivity coefficient through multivariate statistical analysis.

[0076] Specifically, based on core experiments in tight reservoirs, the stress sensitivity coefficient was determined by statistical regression analysis of the core stress sensitivity test data.

[0077] As an alternative, the pseudo-time for material equilibrium can be calculated using the following formula:

[0078]

[0079] The normalized yield, taking into account the effects of stress sensitivity, is calculated using the following formula:

[0080]

[0081] The normalized production integral, taking into account the effects of stress sensitivity, is calculated using the following formula:

[0082]

[0083] The integral derivative of the normalized yield, taking into account the effects of stress sensitivity, is calculated using the following formula:

[0084]

[0085] in, To simulate time for material equilibrium, μ gi The original gas viscosity. Let be the gas viscosity at time t. C ti The overall compression coefficient under the original conditions. Let be the overall compression coefficient at time t. q The daily gas production is represented by t, where t is the production time. To account for the stress-sensitive effects on the normalized production, To account for the stress-sensitive effect of the pseudo-pressure difference, To account for the original pseudo-pressure of the gas well in the case of stress sensitivity, To account for the stress-sensitive effects of the simulated bottom hole flow pressure, To account for the stress-sensitive effects of the normalized production integral, To account for the stress-sensitive effects of the normalized production integral derivative, the subscript is... i For integration, subscript id It is the integral derivative.

[0086] Specifically, ① the simulated time for gas well material balance t αd

[0087] (4)

[0088] ② Gas well regularization production considering stress sensitivity effects q αd

[0089] (5)

[0090] ③ Gas well regularization production integral considering stress sensitivity effects q αdi

[0091] (6)

[0092] ④ Integral derivative of well regularization production considering stress sensitivity q αdid

[0093] (7).

[0094] As an alternative, the original pseudo-pressure of the gas well, taking into account the effects of stress sensitivity, can be calculated using the following formula:

[0095]

[0096] The pseudo-bottomhole flow pressure, taking into account stress-sensitive effects, is calculated using the following formula:

[0097]

[0098] in, p 0 represents any reference pressure, and can be taken as 0. p i The original formation pressure of the reservoir, p wf For the bottom hole flowing pressure, μ g Let Z be the gas viscosity and Z be the gas deviation factor. α This is the stress sensitivity coefficient.

[0099] Based on the study of reservoir seepage mechanism, tight low-permeability reservoirs are subject to stress sensitivity. Considering stress sensitivity, the reservoir seepage equation is:

[0100] (1)

[0101] In the formula: r Let m be the distance from any point to the well point. 3 / d; k i The original permeability of the reservoir, 10 -3 μm 2 ; μ g Where is the gas viscosity, mPa·s; Z This is the gas deviation factor, a decimal. α The permeability stress sensitivity coefficient is given in MPa. -1 ; Porosity, decimal; p The reservoir pressure is expressed in MPa. p i The original formation pressure of the reservoir is MPa; C t The overall compressibility factor is expressed in MPa. -1 .

[0102] Considering the effects of stress sensitivity, the pseudo-pressure and pseudo-time of the gas well are redefined. The reservoir flow equation considering the effects of stress sensitivity then becomes:

[0103] (3)

[0104] in,

[0105] ,

[0106]

[0107] .

[0108] In the formula: ψ α The simulated pressure of the gas well, taking into account the effects of stress sensitivity, is measured in MPa. t α The simulated time for gas wells, d, is calculated to account for stress sensitivity. μ gi The original gas viscosity is given in mPa·s. C ti The overall compressibility coefficient under the original conditions is given in MPa. -1 .

[0109] By comparing the conventional seepage equations that do not consider stress sensitivity, it can be seen that by defining a pseudo-pressure that takes into account the influence of stress sensitivity, the nonlinear terms caused by the stress sensitivity effect are linearized, ultimately yielding the same form as the conventional reservoir seepage equations. Therefore, by redefining the pseudo-parameters, the dynamic reserves and other parameters of tight reservoir gas wells with stress sensitivity can be evaluated using conventional gas well production instability analysis charts.

[0110] As an optional method, the dynamic reserves of the first gas well can be calculated using the following formula:

[0111]

[0112] The dynamic reserves of the second gas well are calculated using the following formula:

[0113]

[0114] in,

[0115] Among them, G1 represents the dynamic reserves of the first gas well. C t q represents the overall compression coefficient. Dd G1 represents the dimensionless normalized production rate of the marker point within the overlapping preset curve, and G2 represents the dynamic reserves of the second gas well. h For reservoir thickness, B The gas volume coefficient, A For the area of ​​air leakage, C A For shape factor, γ Let Euler's constant be 1. r w Where is the wellbore radius;

[0116] Reservoir parameters are calculated using the following formula:

[0117]

[0118]

[0119] Crack parameters are calculated using the following formula:

[0120]

[0121] in, k For penetration rate, r e For the vent radius, r eD The dimensionless vent radius is also a position number. x f For half the length of the crack, Porosity S w This represents the water saturation level.

[0122] Specifically, based on the final fitted location and combined with the following equations (10) to (13), the parameters of each gas well in the tight reservoir (dynamic reserves of the first gas well), reservoir parameters (permeability, venting radius), and fracture parameters (fracture half-length) can be obtained. Taking an infinitely conductive fractured vertical well as an example,

[0123] (10)

[0124] (11)

[0125] (12)

[0126] (13)

[0127] in: t Dd For dimensionless mass equilibrium, the approximate time is given; q Dd The dimensionless, normalized output is dimensionless. k For penetration rate, r e Let vent radius be m; r eD The dimensionless leakage radius is dimensionless. x f The crack half-length is in meters (m). G 1 represents the dynamic reserves of the gas well, in m 3 ; S w This represents the water saturation level, a decimal.

[0128] Meanwhile, considering stress sensitivity, the material balance equation for tight reservoir gas well flow is:

[0129] (8)

[0130] in,

[0131] In the formula, h Let be the reservoir thickness, in meters (m). B m is the gas volume coefficient. 3 / m 3 ; A For the air venting area, m 2 ; C A The shape factor is a decimal. γ Let Euler's constant be a decimal. r w Let be the radius of the wellbore, in meters (m).

[0132] Then, considering the stress-sensitive effects of gas well regularization cumulative gas production G αd ,

[0133] (9)

[0134] Set the left side of Equation 8 to zero, and solve Equation 8 to obtain G2. That is, solve the flow material balance equation considering the stress sensitivity effect of the gas well, construct the relationship curve between the regularized production and the regularized cumulative gas production considering the stress sensitivity effect, and finally determine the size of the dynamic reserves of the second gas well by the intersection of the curve and the horizontal axis based on the linear relationship of the boundary control flow stage.

[0135] By combining the chart fitting method and the fluid mass balance method, the average dynamic reserves of two gas wells are calculated, ultimately determining a reasonable dynamic reserve for each gas well. G In addition to other gas well parameters, reservoir parameters, and fracture parameters.

[0136] The present invention also provides an electronic device, comprising: a memory storing executable instructions; and a processor that executes the executable instructions in the memory to implement the above-mentioned method for evaluating tight reservoir gas well parameters based on stress-sensitive effects.

[0137] Example 1

[0138] Figure 1 A flowchart of a method for evaluating parameters of tight reservoir gas wells based on stress-sensitive effects according to an embodiment of the present invention is shown. Figure 2 The diagram shows the results of a plate fitting method considering the stress-sensitive effects of a tight reservoir gas well parameter evaluation method based on an embodiment of the present invention. Figure 3 The diagram shows the results of a flow mass balance method considering the stress-sensitive effects of a tight reservoir gas well parameter evaluation method based on an embodiment of the present invention. Figure 4Actual gas well production data are shown for a method for evaluating tight reservoir gas well parameters based on stress-sensitive effects according to an embodiment of the present invention. Figure 5 The bottomhole flowing pressure of a tight reservoir gas well based on a stress-sensitive effect evaluation method according to an embodiment of the present invention is shown. Figure 6 The diagram shows a stress-sensitive fitting plot of a tight reservoir core according to an embodiment of the present invention, which is a method for evaluating tight reservoir gas well parameters based on stress-sensitive effects. Figure 7 The diagram shows a gas well plot before fitting, according to an embodiment of the present invention, a method for evaluating tight reservoir gas well parameters based on stress-sensitive effects. Figure 8 A schematic diagram of the well plate fitting results of a tight reservoir gas well parameter evaluation method based on stress-sensitive effects according to an embodiment of the present invention is shown. Figure 9 The diagram illustrates the well fitting results based on the flow mass balance equation for a tight reservoir gas well parameter evaluation method based on stress-sensitive effects according to an embodiment of the present invention.

[0139] Combination Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 , Figure 6 , Figure 7 , Figure 8 and Figure 9 As shown, this method for evaluating tight reservoir gas well parameters based on stress-sensitive effects includes:

[0140] Step 1: Obtain actual production data from the gas well;

[0141] Step 2: Determine the reservoir stress sensitivity coefficient;

[0142] Determining the reservoir stress sensitivity coefficient involves analyzing experimental data on the stress sensitivity of tight reservoir cores under different test pressures and performing multivariate statistical analysis to determine the reservoir stress sensitivity coefficient.

[0143] Step 3: Based on actual production data, calculate the pseudo-time of material balance. Based on actual production data and reservoir stress sensitivity coefficient, calculate the original pseudo-pressure and pseudo-bottom flow pressure of the gas well considering the influence of stress sensitivity. Then, calculate the normalized production, normalized production integral, and normalized production integral derivative considering the influence of stress sensitivity, and obtain the normalized production-material balance pseudo-time curve, normalized production integral-material balance pseudo-time curve, and normalized production integral derivative-material balance pseudo-time curve considering the influence of stress sensitivity.

[0144] Step 4: Fit the normalized production-material balance pseudo-time curve, normalized production integral-material balance pseudo-time curve, and normalized production integral derivative-material balance pseudo-time curve to the typical curve chart of production instability analysis, respectively, to determine the time shift, production shift, and number of positions.

[0145] Among them, the typical curve chart for yield instability analysis includes multiple sets of preset curves. Each set of preset curves includes a preset dimensionless normalized yield-material balance pseudo-time curve, a preset dimensionless normalized yield integral-material balance pseudo-time curve, and a preset dimensionless normalized yield integral derivative-material balance pseudo-time curve.

[0146] Specifically, the normalized production-mass balance pseudo-time curve, normalized production integral-mass balance pseudo-time curve, and normalized production integral derivative-mass balance pseudo-time curve considering stress sensitivity effects are respectively fitted to the typical curve chart for production instability analysis to determine the time shift, production shift, and number of positions. This includes: plotting the normalized production-mass balance pseudo-time curve, normalized production integral-mass balance pseudo-time curve, and normalized production integral derivative-mass balance pseudo-time curve considering stress sensitivity effects on the typical curve chart for production instability analysis; using any point in any of the normalized production-mass balance pseudo-time curve, normalized production integral-mass balance pseudo-time curve, or normalized production integral derivative-mass balance pseudo-time curve considering stress sensitivity effects as a marker point to obtain the initial position of the marker point; and then... In the line graph version, the normalized production-material balance pseudo-time curve, normalized production integral-material balance pseudo-time curve, and normalized production integral derivative-material balance pseudo-time curve, which consider the influence of stress sensitivity, are moved along the horizontal and vertical axes until they coincide with the preset dimensionless normalized production-material balance pseudo-time curve, preset dimensionless normalized production integral-material balance pseudo-time curve, and preset dimensionless normalized production integral derivative-material balance pseudo-time curve in the same set of preset curves. The final position of the marker point is obtained. Based on the initial and final positions, the time shift and production shift are calculated. The number of sets of preset curves that coincide is taken as the position number.

[0147] The time shift k is calculated using the following formula. s :

[0148]

[0149] The production movement k is calculated using the following formula. q :

[0150]

[0151] in, t αd The time at the initial position is also the pseudo-time of the mass equilibrium at the marked point. The time for the final position is also the dimensionless mass equilibrium time for the marker point to be within the coincident preset curve. q αd The output at the initial position is also the normalized output at the marked point. The output at the final position is also the dimensionless normalized output of the marker point in the pre-defined curve that coincides with the final position.

[0152] Step 5: Calculate the dynamic reserves of the first gas well based on the time shift.

[0153] Step 6: Based on the flow material balance equation, obtain the dynamic reserves of the second gas well. Use the average of the dynamic reserves of the first gas well and the dynamic reserves of the second gas well as the dynamic reserves of the gas well under the mutual constraint of the flow material balance method and the chart fitting method.

[0154] Step 7: Calculate reservoir parameters and fracture parameters based on the amount of movement and the number of locations produced.

[0155] The actual production data includes: daily gas production. t Gas production rate at any given moment, production time t The original formation pressure and bottom hole flowing pressure of the reservoir.

[0156] The pseudo-time of material equilibrium, taking into account the effects of stress sensitivity, is calculated using the following formula:

[0157]

[0158] The normalized yield, taking into account the effects of stress sensitivity, is calculated using the following formula:

[0159]

[0160] The normalized production integral, taking into account the effects of stress sensitivity, is calculated using the following formula:

[0161]

[0162] The integral derivative of the normalized yield, taking into account the effects of stress sensitivity, is calculated using the following formula:

[0163]

[0164] in, To simulate time for material equilibrium, μ gi The original gas viscosity. Let be the gas viscosity at time t. C ti The overall compression coefficient under the original conditions. Let be the overall compression coefficient at time t. q The daily gas production is represented by t, where t is the production time. To account for the stress-sensitive effects on the normalized production, To account for the stress-sensitive effect of the pseudo-pressure difference, To account for the original pseudo-pressure of the gas well in the case of stress sensitivity, To account for the stress-sensitive effects of the simulated bottom hole flow pressure, To account for the stress-sensitive effects of the normalized production integral, To account for the stress-sensitive effects of the normalized production integral derivative, the subscript is... i For integration, subscript id It is the integral derivative.

[0165] The original pseudo-pressure of the gas well, taking into account the effects of stress sensitivity, is calculated using the following formula:

[0166]

[0167] The pseudo-bottom flow pressure, considering stress-sensitive effects, is calculated using the following formula:

[0168]

[0169] in, p 0 represents any reference pressure, and can be taken as 0. p i The original formation pressure of the reservoir, p wf For the bottom hole flowing pressure, μ g Let Z be the gas viscosity and Z be the gas deviation factor. α This is the stress sensitivity coefficient.

[0170] The dynamic reserves of the first gas well are calculated using the following formula:

[0171]

[0172] The dynamic reserves of the second gas well are calculated using the following formula:

[0173]

[0174] in,

[0175] in, G 1 represents the dynamic reserves of the first gas well. C t The overall compression coefficient is... qDd The output of the marker point within the overlapping preset curve. G 2 represents the dynamic reserves of the second gas well. h For reservoir thickness, B The gas volume coefficient, A For the area of ​​air leakage, C A For shape factor, γ Let Euler's constant be 1. r w Where is the wellbore radius;

[0176] Reservoir parameters are calculated using the following formula:

[0177]

[0178]

[0179] Crack parameters are calculated using the following formula:

[0180]

[0181] in, k For penetration rate, r e For the vent radius, r eD The dimensionless vent radius is also a position number. x f For half the length of the crack, Porosity S w This represents the water saturation level.

[0182] Taking a production well in an actual gas reservoir as an example, the accuracy and reliability of the method of the present invention are verified. The basic parameter settings of the model containing the production well are shown in Table 1, and its production data are as follows: Figure 4 and 5 As shown, the production data includes: daily water production, daily gas production, bottom hole flowing pressure, and water-to-gas ratio. The overall water-to-gas ratio is small, which can be considered as a condensate-gas producing well, and the formation water is bound water.

[0183] Table 1 Basic parameters of the reservoir where the production well is located

[0184]

[0185] By analyzing the stress sensitivity test data of the core samples from the tight reservoir where the well is located under different test pressures, the magnitude of the reservoir stress sensitivity coefficient can be quantitatively obtained through multivariate statistical analysis. Compared with medium and high permeability reservoirs, low-permeability tight reservoirs have a greater decrease in permeability and a larger stress sensitivity effect due to their tightness. Figure 6 This is a stress-sensitive fitting diagram of a uniformly dense reservoir core.

[0186] An exponential relationship was used to fit the relationship between permeability and effective stress during the depressurization process to determine the permeability-stress sensitivity coefficient for different types of reservoirs. Based on the reservoir conditions in the mechanistic model, the stress sensitivity coefficient for this well was given as 0.03 MPa. -1 .

[0187] (14)

[0188] The relationship curves between the normalized parameters, considering the influence of stress sensitivity, and the material balance pseudo-time were obtained from the actual production data of the gas well. The curves were then fitted to the graphs, and finally, the gas well parameters, reservoir parameters, and fracture parameters were quantitatively obtained according to the corresponding formulas.

[0189] Based on the corresponding formula and the magnitude of the stress sensitivity coefficient determined experimentally, the normalized yield considering the influence of stress sensitivity can be calculated. q αd Regularized production integral q αdi Regularized product integral derivative q αdid and material balance pseudotime t αd The production time of each gas well will be obtained. q αd ~ t αd , q αdi ~ t αd , q αdid ~ t αd Three relationship curves were used to fit a typical curve chart for yield instability analysis. The fitting results are as follows: Figure 8 As shown. Through fitting, it can be determined... r eD =12, t αd / t Dd =1 / 0.002, q αd / q Dd =1 / 0.0003.

[0190] Then, based on the formula, the following gas well parameters, reservoir parameters, and fracture parameters can be determined:

[0191]

[0192]

[0193]

[0194]

[0195] Based on the flow mass balance equation for gas wells considering stress sensitivity, a relationship curve between regularized production and regularized cumulative gas production, taking into account stress sensitivity, is constructed. Finally, based on the linear relationship in the boundary control flow stage, the dynamic reserves of the gas well can be determined. The flow mass balance method and the chart fitting method are mutually constrained, and the corresponding gas well parameters, reservoir parameters, and fracture parameters are quantitatively obtained using appropriate formulas.

[0196] The following are the fitting results:

[0197] Table 2 Fitting Results

[0198]

[0199] A comparison between the fitted parameter values ​​and the actual values ​​of the mechanistic model parameters shows that the gas well parameters and reservoir parameters obtained after fitting the well normalized parameters considering the stress-sensitive effects are more accurate. By adopting the definitions of stress-sensitive normalized parameters and material balance pseudo-time, the errors in parameter results obtained by fitting using only conventional methods can be eliminated. This method is highly practical for parameter fitting of gas wells in low-permeability tight water-bearing reservoirs with significant stress sensitivity.

[0200] Example 2

[0201] This disclosure provides an electronic device comprising: a memory storing executable instructions; and a processor executing the executable instructions in the memory to implement the aforementioned method for evaluating tight reservoir gas well parameters based on stress-sensitive effects.

[0202] An electronic device according to an embodiment of the present disclosure includes a memory and a processor.

[0203] This memory is used to store non-transitory computer-readable instructions. Specifically, the memory may include one or more computer program products, which may include various forms of computer-readable storage media, such as volatile memory and / or non-volatile memory. The volatile memory may, for example, include random access memory (RAM) and / or cache memory. The non-volatile memory may, for example, include read-only memory (ROM), hard disk, flash memory, etc.

[0204] The processor may be a central processing unit (CPU) or other form of processing unit with data processing capabilities and / or instruction execution capabilities, and may control other components in the electronic device to perform desired functions. In one embodiment of this disclosure, the processor is used to execute computer-readable instructions stored in the memory.

[0205] Those skilled in the art should understand that, in order to solve the technical problem of how to obtain a good user experience, this embodiment may also include well-known structures such as communication buses and interfaces, and these well-known structures should also be included within the protection scope of this disclosure.

[0206] For a detailed description of this embodiment, please refer to the corresponding descriptions in the foregoing embodiments, which will not be repeated here.

[0207] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A method for evaluating parameters of tight reservoir gas wells based on stress-sensitive effects, characterized in that, include: Obtain actual production data from gas wells; Determine the reservoir stress sensitivity coefficient; Based on the actual production data, the material balance pseudo-time is calculated. Based on the actual production data and the reservoir stress sensitivity coefficient, the original pseudo-pressure and pseudo-bottom flow pressure of the gas well considering the influence of stress sensitivity are calculated. Then, the normalized production, normalized production integral, and normalized production integral derivative considering the influence of stress sensitivity are calculated to obtain the normalized production-material balance pseudo-time curve, normalized production integral-material balance pseudo-time curve, and normalized production integral derivative-material balance pseudo-time curve considering the influence of stress sensitivity. The normalized production-material balance pseudo-time curve, normalized production integral-material balance pseudo-time curve, and normalized production integral derivative-material balance pseudo-time curve considering stress sensitivity effects are respectively fitted to the typical curve chart of production instability analysis to determine the time shift, production shift, and number of positions. Based on the time shift, calculate the dynamic reserves of the first gas well; Based on the flow material balance equation, the dynamic reserves of the second gas well are obtained. The average value of the dynamic reserves of the first gas well and the dynamic reserves of the second gas well is taken as the dynamic reserves of the gas well under the mutual constraint of the flow material balance method and the chart fitting method. Based on the production movement and the number of locations, reservoir parameters and fracture parameters are calculated; The dynamic reserves of the first gas well are calculated using the following formula: The dynamic reserves of the second gas well are calculated using the following formula: in, ,in, G 1 represents the dynamic reserves of the first gas well. C t The overall compression coefficient is... q Dd The dimensionless yield of the marker point within the overlapping preset curve. G 2 represents the dynamic reserves of the second gas well. h For reservoir thickness, B The gas volume coefficient, A For the area of ​​air leakage, C A For shape factor, γ Let Euler's constant be 1. r w Where is the wellbore radius. t αd The time at the initial position is also the pseudo-time of the mass equilibrium at the marked point. The dimensionless time for the final position is also the time it takes for the marker point to travel along the overlapping preset curve. To account for the stress-sensitive effect of the pseudo-pressure difference, C ti The overall compression coefficient under the original conditions. q Daily gas production To account for the original pseudo-pressure of the gas well in the case of stress sensitivity, To account for the stress-sensitive effects of the simulated bottom hole flow pressure, μ g Gas viscosity; Reservoir parameters are calculated using the following formula: Crack parameters are calculated using the following formula: in, k For penetration rate, r e For the vent radius, r eD The dimensionless vent radius is also a position number. x f For half the length of the crack, Porosity S w This represents the water saturation level. q αd The output at the initial position is also the normalized output at the marked point.

2. The method for evaluating tight reservoir gas well parameters based on stress-sensitive effects according to claim 1, characterized in that, The typical curve chart for yield instability analysis includes multiple sets of preset curves. Each set of preset curves includes a preset dimensionless normalized yield-material balance pseudo-time curve, a preset dimensionless normalized yield integral-material balance pseudo-time curve, and a preset dimensionless normalized yield integral derivative-material balance pseudo-time curve.

3. The method for evaluating tight reservoir gas well parameters based on stress-sensitive effects according to claim 2, characterized in that, The process involves fitting the normalized yield-mass balance pseudo-time curve, normalized yield integral-mass balance pseudo-time curve, and normalized yield integral derivative-mass balance pseudo-time curve, which consider stress sensitivity effects, to typical curve charts for yield instability analysis, respectively, to determine the time shift, yield shift, and number of positions, including: The regularized production-material balance pseudo-time curve, regularized production integral-material balance pseudo-time curve, and regularized production integral derivative-material balance pseudo-time curve considering stress sensitivity are respectively plotted on the typical curve chart of production instability analysis. Any point in the regularized production-material balance pseudo-time curve, regularized production integral-material balance pseudo-time curve, or regularized production integral derivative-material balance pseudo-time curve considering stress sensitivity is used as a marker point, and the initial position of the marker point is obtained. In the typical curve chart for the production instability analysis, the regularized production-material balance pseudo-time curve, regularized production integral-material balance pseudo-time curve, and regularized production integral derivative-material balance pseudo-time curve considering stress sensitivity are moved along the horizontal and vertical axes until they coincide with the preset dimensionless regularized production-material balance pseudo-time curve, preset dimensionless regularized production integral-material balance pseudo-time curve, and preset dimensionless regularized production integral derivative-material balance pseudo-time curve in the same set of preset curves. Obtain the final position of the marker point; Based on the initial position and the final position, calculate the time movement and production movement; use the number of overlapping preset curves as the position number.

4. The method for evaluating tight reservoir gas well parameters based on stress-sensitive effects according to claim 3, characterized in that, The time shift k is calculated using the following formula. s : The production movement k is calculated using the following formula. q : in, The dimensionless output of the final position is also the normalized output of the marker point in the overlapping preset curve.

5. The method for evaluating tight reservoir gas well parameters based on stress-sensitive effects according to claim 3, characterized in that, The actual production data includes: daily gas production, gas production at time t, production time t, original formation pressure of the reservoir, and bottom hole flowing pressure.

6. The method for evaluating tight reservoir gas well parameters based on stress-sensitive effects according to claim 1, characterized in that, Determining the magnitude of the reservoir stress sensitivity coefficient includes: By analyzing the stress sensitivity test data of tight reservoir cores under different test pressures, the stress sensitivity coefficient of the reservoir was determined through multivariate statistical analysis.

7. The method for evaluating tight reservoir gas well parameters based on stress-sensitive effects according to claim 4, characterized in that, The pseudo-time of the material equilibrium is calculated using the following formula. t αd : The normalized yield is calculated using the following formula. q αd : The normalized production integral considering stress sensitivity effects is calculated using the following formula. q αdi : The integral derivative of the normalized yield considering stress sensitivity effects is calculated using the following formula. q αdid : in, To simulate time for material equilibrium, μ gi The original gas viscosity. Let be the gas viscosity at time t. Let be the overall compression coefficient at time t, where t is the production time. To account for the stress-sensitive effects of normalized production, To account for the stress-sensitive effects of the normalized production integral, To account for the stress-sensitive effects of the normalized production integral derivative, the subscript is... i For integration, subscript id It is the integral derivative.

8. The method for evaluating tight reservoir gas well parameters based on stress-sensitive effects according to claim 7, characterized in that, The original pseudo-pressure of the gas well, taking into account the effects of stress sensitivity, is calculated using the following formula: The pseudo-bottomhole flow pressure, taking into account stress-sensitive effects, is calculated using the following formula: in, p 0 represents a certain reference pressure, which can be taken as 0, p i The original formation pressure of the reservoir, p wf For bottom hole flowing pressure, Z For gas deviation factor, α This is the stress sensitivity coefficient.

9. An electronic device, characterized in that, The electronic device includes: Memory, which stores executable instructions; A processor that executes the executable instructions in the memory to implement the tight reservoir gas well parameter evaluation method based on stress-sensitive effects as described in claims 1-8.

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