Explicit determination method and device of gas well dynamic reserves and storage medium

Abstract

The application provides a method and device for explicitly determining the dynamic reserves of a gas well and a storage medium. The method comprises the following steps: determining the first actual gas production data and the first estimated gas production data of the gas well; determining the first relationship between the first actual gas production data, the first estimated gas production data and the dimensionless pressure according to the first actual gas production data and the first estimated gas production data; determining the relationship between the dimensionless pressure and the target time according to the first relationship and the second relationship; and determining the dynamic reserves of the gas well according to the relationship between the dimensionless pressure and the target time and the cumulative gas production data. The method optimizes the algorithm for calculating the dynamic reserves of the gas well and improves the adaptability to various conditions during the development of the gas well.

Description

Technical Field

[0001] This application relates to the field of oil and gas field development technology, and in particular to a method, apparatus and storage medium for explicitly determining the dynamic reserves of gas wells. Background Technology

[0002] A gas reservoir is an underground storage container filled with gas. Its dynamic reserves refer to the total amount of gas involved in the flow within the reservoir. Determining the reserves of a gas reservoir is related to gas reservoir development planning and gas well production design.

[0003] Currently, common methods for calculating reserves include the volumetric method, the mass balance method, unsteady gauging analysis, and production decline analysis (typical curve analysis). Curve fitting methods require analysis and iteration of data from gas wells in the production decline phase, and there are strong multiple solutions when fitting measured data with typical curves. The volumetric method and the mass balance method are generally applied to gas fields or gas reservoirs. The mass balance method requires regular, long-term shut-in pressure testing of the entire gas reservoir. Unsteady gauging and production decline analysis mainly use specialized software to analyze and calculate well-controlled reserves.

[0004] However, the difficulty in obtaining formation pressure currently leads to problems such as poor adaptability and cumbersome calculation methods for calculating dynamic reserves of gas wells. Summary of the Invention

[0005] This application provides a method, apparatus, and storage medium for explicitly determining the dynamic reserves of gas wells, in order to solve the problems of poor adaptability and cumbersome calculation in current reserve calculation methods.

[0006] In a first aspect, this application provides a method for explicitly determining the dynamic reserves of a gas well, including:

[0007] The first actual gas production data and the first estimated gas production data of the gas well are determined. The first actual gas production data is obtained by integrating the target parameters based on the dimensionless pressure and dimensionless bottom hole pressure of the gas well. The first estimated gas production data is obtained by integrating the target parameters based on the dimensionless bottom hole pressure and the target dimensionless pressure. The target parameters are determined based on the natural gas viscosity and natural gas compressibility coefficient in the PVT data under different pressures. The dimensionless pressure is determined based on the natural gas deviation factor and formation pressure in the PVT data under different pressures.

[0008] Based on the first actual gas production data and the first estimated gas production data, a first relationship between the first actual gas production data, the first estimated gas production data, and the dimensionless pressure is determined.

[0009] Based on the first and second relationships, the relationship between dimensionless pressure and target time is determined. The second relationship characterizes the relationship between the second actual gas production data, the second estimated gas production data, and the target time. The second actual gas production data is the data of the gas well when it is in the boundary control flow stage. Both the second actual gas production data and the second estimated gas production data are determined based on the gas well data.

[0010] Based on the relationship between dimensionless pressure and target time, and cumulative gas production data, the dynamic reserves of the gas well are determined.

[0011] In this embodiment of the application, before determining the first actual gas production data and the first estimated gas production data of the gas well, the method further includes:

[0012] Determine the viscosity and compressibility of natural gas in PVT data under different pressures;

[0013] Based on the natural gas viscosity and compressibility coefficient from PVT data under different pressures, the target parameters are obtained, whereby the target parameters satisfy:

[0014]

[0015] μ g Natural gas viscosity, unit: MPa·s; c g The compressibility coefficient of natural gas, in MPa. -1 μ gi The viscosity of natural gas under the original formation pressure, in MPa·s; c gi The compressibility coefficient of natural gas under the original formation pressure, in MPa. -1 .

[0016] In this embodiment of the application, before determining the first actual gas production data and the first estimated gas production data of the gas well, the method further includes:

[0017] Determine the natural gas deviation factor in PVT data under different pressures;

[0018] Based on the natural gas deviation factor in the PVT data under different pressures, the dimensionless pressure is obtained, where the dimensionless pressure satisfies:

[0019]

[0020] p represents formation pressure in MPa; z is the natural gas deviation factor, dimensionless; p i Original formation pressure, unit: MPa; z i This is the natural gas deviation factor under the original formation pressure, and it is dimensionless.

[0021] In this embodiment of the application, before determining the first relationship between the first actual gas production data, the first estimated gas production data, and the dimensionless pressure based on the first actual gas production data and the first estimated gas production data, the method further includes:

[0022] When the gas well is in the boundary control flow stage, the dimensionless gas well production is obtained based on the first actual gas production data and the first estimated gas production data, wherein the dimensionless gas well production satisfies:

[0023]

[0024] Where, q gi,1 This is the initial estimated gas production data at the beginning of the time, in units of 10. 4 m 3 / d;q g,j The first actual gas production data at any given time, in units of 10. 4 m 3 / d;P wD The bottom pressure is dimensionless; P is dimensionless. wD,1 P is the dimensionless bottom hole pressure at the initial moment, which is dimensionless; wD,j p is the dimensionless bottom hole pressure at any given time; λ is the objective parameter; D For dimensionless pressure, dimensionless.

[0025] In this embodiment of the application, before determining the relationship between dimensionless pressure and target time based on the first relationship and the second relationship, the method further includes:

[0026] Establish a production operation system for gas wells;

[0027] If the gas well maintains a constant bottom pressure for production, then determine the well's decline rate, production time, and actual gas production data.

[0028] Based on the well decline rate, production time, and actual gas production data, a first linear relationship is established between the initial estimated gas production data, actual gas production data, and production time. This first linear relationship is as follows:

[0029] ln(q g )=-D i t+ln(q gi ),

[0030] q g Actual gas production data, unit: 10 4 m 3 / d;q gi Initial estimated gas production data, unit: 10 4 m 3 / d;D i Initial decline rate, unit: day-1 t represents production time, in days.

[0031] If the initial estimated gas production data, the actual gas production data, and the production time satisfy the first linear relationship, then the actual gas production data is determined as the second actual gas production data, and the production time is the target time.

[0032] In this embodiment of the application, after determining the production operating schedule of the gas well, the method further includes:

[0033] If the gas well maintains a constant gas production rate, then determine the bottom hole flowing pressure and production time of the gas well;

[0034] Based on the bottomhole flowing pressure and production time of the gas well, determine whether the bottomhole flowing pressure and production time of the gas well satisfy the second linear relationship, where the second linear relationship is:

[0035]

[0036] Ψ(p wf () represents the bottom hole flowing pressure, in MPa. 2 / (MPa·s); Ψ(p i () represents the original formation pressure and pseudo-pressure, in MPa. 2 / (MPa·s); p sc The pressure under standard conditions; q g Actual gas production data, unit: 10 4 m 3 / d; T is the air layer temperature, unit: K; T sc Temperature under standard conditions; K is gas layer permeability, in mD; h is gas layer thickness, in m; t is production time, in day; φ is porosity, in %; μ is gas viscosity, in MPa·s; C t The overall compressibility factor is expressed in MPa. -1 ;r w S represents the wellbore radius in meters; S represents the skin factor.

[0037] If the bottom-hole flowing pressure and production time of the gas well do not satisfy the second linear relationship, then the actual gas production data is determined as the second actual gas production data, and the production time is the target time.

[0038] In this embodiment of the application, before determining the relationship between dimensionless pressure and target time based on the first relationship and the second relationship, the method further includes:

[0039] Determine the relationship between the second actual gas production data and time;

[0040] A relationship curve is generated based on the relationship between the second actual gas production data and time.

[0041] The relationship curve is fitted to obtain the target relationship curve;

[0042] Based on the target relationship curve, determine the second estimated gas production data;

[0043] Determine the second relationship between the second actual gas production data, the second estimated gas production data, and the target time.

[0044] In this embodiment of the application, after determining the relationship between dimensionless pressure and target time based on the first relationship and the second relationship, the method further includes:

[0045] Based on the relationship between dimensionless pressure and target time, the relationship between formation pressure and target time is obtained;

[0046] The average formation pressure of the gas well is determined based on the relationship between formation pressure and target time.

[0047] Secondly, this application provides an explicit device for determining the dynamic reserves of a gas well, comprising:

[0048] The first determining module is used to determine the first actual gas production data and the first estimated gas production data of the gas well. The first actual gas production data is obtained by integrating the target parameters based on the dimensionless pressure and dimensionless bottom hole pressure of the gas well. The first estimated gas production data is obtained by integrating the target parameters based on the dimensionless bottom hole pressure and the target dimensionless pressure. The target parameters are determined based on the natural gas viscosity and natural gas compressibility coefficient in the PVT data under different pressures. The dimensionless pressure is determined based on the natural gas deviation factor and formation pressure in the PVT data under different pressures.

[0049] The second determining module is used to determine the first relationship between the first actual gas production data, the first estimated gas production data, and the dimensionless pressure based on the first actual gas production data and the first estimated gas production data.

[0050] The third determining module is used to determine the relationship between dimensionless pressure and target time based on the first relationship and the second relationship. The second relationship represents the relationship between the second actual gas production data, the second estimated gas production data and the target time. The second actual gas production data is the data of the gas well when it is in the boundary control flow stage. Both the second actual gas production data and the second estimated gas production data are determined based on the gas well data.

[0051] The fourth determination module is used to determine the dynamic reserves of the gas well based on the relationship between dimensionless pressure and target time, and the cumulative gas production data.

[0052] Thirdly, this application provides a computer-readable storage medium storing computer-executable instructions, which, when executed by a processor, are used to implement the explicit method for determining the dynamic reserves of a gas well according to embodiments of this application.

[0053] The explicit method, apparatus, and storage medium for determining the dynamic reserves of gas wells provided in this application determine the first actual gas production data and the first estimated gas production data of the gas well; based on the first actual gas production data and the first estimated gas production data, determine the first relationship between the first actual gas production data, the first estimated gas production data, and dimensionless pressure; based on the first relationship and the second relationship, determine the relationship between dimensionless pressure and target time; based on the relationship between dimensionless pressure and target time and cumulative gas production data, determine the means of determining the dynamic reserves of the gas well; based on the relationship between the target parameter and the dimensionless pressure, combined with the gas well production calculation formula for a constant-volume closed gas reservoir, derive the dimensionless gas well production calculation formula for the boundary control flow stage by integrating the target parameter, and then deriving the ratio of the first actual gas production data to the first estimated gas production data based on PVT data under different pressures. The first relationship between dimensionless pressure is obtained by estimating the second estimated gas production data through the relationship between the second actual gas production data and the target time. This leads to the determination of the second relationship between the ratio of the second actual gas production data to the second estimated gas production data and the target time. Finally, based on the first and second relationships, the relationship between dimensionless pressure and the target time is determined. Combining this with the relationship between the cumulative gas production data and the target time, a linear relationship between dimensionless pressure and cumulative gas production data is obtained. The intersection of the straight line on the horizontal axis represents the dynamic reserves. Thus, by transforming the relationships between various parameters, the problem of numerous unknowns leading to cumbersome calculations in existing reserve calculation formulas is avoided. Furthermore, the predicted gas production is obtained using only dynamic production data without shutting in the well, thereby avoiding iterative calculations of pseudo-time and pseudo-pressure functions. The dynamic reserves of the gas well can be obtained by observing the relationship curves. Attached Figure Description

[0054] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0055] Figure 1 A flowchart illustrating the explicit method for determining dynamic gas well reserves provided in this application embodiment;

[0056] Figure 2 A flowchart illustrating another method for explicitly determining the dynamic reserves of a gas well, provided as an embodiment of this application;

[0057] Figure 3 A graph of gas well production history data provided for an embodiment of this application;

[0058] Figure 4 A graph showing the relationship between the cumulative gas production and dimensionless pressure of a gas well provided in this application embodiment;

[0059] Figure 5 A schematic diagram of the structure of the explicit determination device for dynamic gas well reserves provided in the embodiments of this application.

[0060] The accompanying drawings illustrate specific embodiments of this application, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the concept in any way, but rather to illustrate the concept of this application to those skilled in the art through reference to particular embodiments. Detailed Implementation

[0061] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0062] In existing technologies, curve fitting methods can only analyze data from gas wells in the declining production phase, and are greatly affected by the well's operating regime. However, in mineral development practice, many gas wells initially adopt production control, and their gas production does not decline, making curve fitting methods unsuitable. Production decline analysis methods all require assuming geological reserves and iteratively fitting actual production data through mean formation pressure, which is a cumbersome calculation process. The PTA (Pressure Transient Analysis) method requires shutting in the well for pressure measurement, which affects production and makes it inconvenient to determine mean formation pressure and dynamic reserves of the gas well.

[0063] To address the aforementioned issues, the dynamic reserve determination method for gas wells provided in this application defines the dimensionless gas well production rate during the boundary control flow stage as a function solely of the gas's PVT parameters and formation pressure, independent of other unknown parameters. This avoids iterative calculations of pseudo-time and pseudo-pressure functions, resolving the computational difficulties caused by an excessive number of unknown parameters. Furthermore, it is not limited by the gas well production operating regime and is applicable to various gas well production operating regimes. Thus, it solves the problems of poor adaptability and cumbersome calculations in current reserve calculation methods.

[0064] The technical solution of this application and how the technical solution of this application solves the above-mentioned technical problems are described in detail below with specific embodiments. These specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments. The embodiments of this application will now be described with reference to the accompanying drawings.

[0065] In this application, the executing entity can be a server. The server can be a device such as a mobile phone, tablet, or computer. This embodiment does not particularly limit the implementation method of the executing entity, as long as the executing entity can execute the method for displaying and determining the dynamic reserves of gas wells as described in the following embodiments. Specifically, the executing entity can be a hardware device of a server, or a software application implementing the following embodiments on a server, or a computer-readable storage medium installed with the software application implementing the following embodiments, or code implementing the software application.

[0066] The following is an explanation of the terms used in this application:

[0067] Natural gas: In a broad sense, it refers to a mixture of naturally occurring hydrocarbon and non-hydrocarbon gases in porous strata below the Earth's surface; in a narrow sense, it refers to natural gas that is mainly composed of hydrocarbons, but contains a certain amount of non-hydrocarbon gases.

[0068] Dynamic reserves: The total amount of natural gas that can be extracted from a gas reservoir when all wells are put into production until the natural gas production and formation pressure within the affected area drop to zero, under the condition that the existing technology and well network extraction methods remain unchanged.

[0069] Figure 1 A flowchart illustrating the explicit method for determining dynamic reserves of gas wells provided in this application embodiment. Figure 1 As shown, using a system for explicitly determining the dynamic reserves of gas wells as the implementing entity, the method in this embodiment may include the following steps:

[0070] S101. Determine the first actual gas production data and the first estimated gas production data of the gas well. The first actual gas production data is obtained by integrating the target parameters based on the dimensionless pressure and dimensionless bottom hole pressure of the gas well. The first estimated gas production data is obtained by integrating the target parameters based on the dimensionless bottom hole pressure and the target dimensionless pressure. The target parameters are determined based on the natural gas viscosity and natural gas compressibility coefficient in the PVT data under different pressures. The dimensionless pressure is determined based on the natural gas deviation factor and formation pressure in the PVT data under different pressures.

[0071] PVT data refers to parameters such as gas deviation factor, volume coefficient, compressibility factor, viscosity, critical pressure, and critical temperature of natural gas. Natural gas PVT data is related to the gas reservoir and the properties of the natural gas, and is affected by temperature and natural gas composition. Natural gas composition parameters refer to the different components contained in different types of natural gas deposits. Natural gas can be classified according to its deposits as gas field gas, associated gas from oil fields, condensate gas, and coalbed methane. PVT data can be calculated based on formation pressure; therefore, PVT data changes when formation pressure changes. Specifically, the gas deviation factor represents the ratio of the actual volume to the ideal volume of the same mass of gas under certain temperature and pressure conditions; the natural gas compressibility factor represents the change in unit volume per unit volume under constant temperature conditions with pressure changes; natural gas viscosity can be defined as a function of pressure, temperature, and gas composition under certain formation conditions; the natural gas volume coefficient can be expressed as the ratio of the underground volume of natural gas to the volume of natural gas under standard surface conditions; and formation pressure refers to the equilibrium pressure of the gas reservoir at a certain extraction stage.

[0072] In this embodiment of the application, the method prior to determining the first actual gas production data and the first estimated gas production data of the gas well may further include:

[0073] Determine the viscosity and compressibility of natural gas in PVT data under different pressures;

[0074] Based on the natural gas viscosity and compressibility coefficient from PVT data under different pressures, the target parameters are obtained, whereby the target parameters satisfy:

[0075]

[0076] μ g Natural gas viscosity, unit: MPa·s; c g The compressibility coefficient of natural gas, in MPa. -1 μ gi The viscosity of natural gas under the original formation pressure, in MPa·s; c gi The compressibility coefficient of natural gas under the original formation pressure, in MPa. -1 .

[0077] The target parameter can refer to the parameters determined based on the natural gas viscosity and compressibility coefficient in PVT data under different pressures. It is calculated by the ratio of the product of the natural gas viscosity and compressibility coefficient under the original formation pressure to the product of the natural gas viscosity and compressibility coefficient under the formation pressure. Here, the formation pressure can refer to non-original formation pressure, which varies according to the actual formation conditions.

[0078] In this embodiment of the application, the method prior to determining the first actual gas production data and the first estimated gas production data of the gas well may further include:

[0079] Determine the natural gas deviation factor in PVT data under different pressures;

[0080] Based on the natural gas deviation factor in the PVT data under different pressures, the dimensionless pressure is obtained, where the dimensionless pressure satisfies:

[0081]

[0082] p represents formation pressure in MPa; z is the natural gas deviation factor, dimensionless; p i Original formation pressure, unit: MPa; z i This is the natural gas deviation factor under the original formation pressure, and it is dimensionless.

[0083] Dimensionless pressure refers to a physical quantity determined based on the natural gas deviation factor and formation pressure in PVT data under different pressures. It has no physical unit and is a pure number. It is calculated by dividing the ratio of formation pressure to natural gas deviation factor by the ratio of original formation pressure to natural gas deviation factor under original formation pressure.

[0084] Dimensionless bottomhole pressure refers to a physical quantity determined based on the natural gas deviation factor and bottomhole flowing pressure in PVT data under different pressures. It has no physical unit and is a pure number. It is calculated by dividing the ratio of bottomhole flowing pressure to the natural gas deviation factor under bottomhole pressure by the ratio of original formation pressure to the natural gas deviation factor under original formation pressure.

[0085] Based on the relationship between the PVT parameters of natural gas and formation pressure, the relationship between dimensionless pressure and formation pressure, and the relationship between the target parameter and the PVT parameters of natural gas, the relationship between the target parameter and the dimensionless pressure can be determined through transformation.

[0086] The first actual gas production data can refer to the actual daily gas production data at any time when the gas well is in the boundary control flow stage. Based on the following gas well production calculation formula, the target parameter is integrated according to the dimensionless pressure and dimensionless bottom hole pressure. The upper limit of the integration of the target parameter is the dimensionless pressure, and the lower limit of the integration is the dimensionless bottom hole pressure at any time, which can be expressed as:

[0087] The first estimated gas production data refers to the estimated daily gas production data at the initial moment when the gas well is in the boundary control flow stage. Based on the dimensionless bottom hole pressure and the target dimensionless pressure, the target parameter is integrated to obtain the data. Since the original formation pressure is equal to the formation pressure in the boundary control flow stage, the target dimensionless pressure is equal to 1. Therefore, the gas well production calculation formula can be modified by setting the upper limit of integration of the target parameter to 1 and the lower limit of integration to the initial dimensionless bottom hole pressure. The other parameters in the formula remain unchanged and can be expressed as follows:

[0088] The formula for calculating gas well production is as follows:

[0089]

[0090] q g Actual gas production data, unit: 10 4 m 3 / d;J g Gas well production index, unit: 10 4 m 3 / d / MPa;c gi The compressibility coefficient of natural gas under the original formation pressure, in MPa. -1 ;p D For dimensionless pressure, dimensionless; P wD λ represents the dimensionless bottom hole pressure, which is dimensionless; λ is the target parameter.

[0091] Bottom hole pressure can refer to the total pressure exerted at the bottom of the well by various pressures from the surface and within the well. Dimensionless bottom hole pressure can refer to a physical value calculated based on the conditions of the gas well in the formation, and its calculation formula is as follows:

[0092]

[0093] p wf Bottom hole flowing pressure, unit: MPa; z wf p is the deviation factor under bottom hole pressure, dimensionless; i Original formation pressure, unit: MPa; z i It is the deviation factor under the original formation pressure, and is dimensionless.

[0094] S102. Based on the first actual gas production data and the first estimated gas production data, determine the first relationship between the first actual gas production data, the first estimated gas production data, and the dimensionless pressure.

[0095] The first relationship can refer to the calculation of the ratio of the first actual gas production data to the first estimated gas production data by substituting the PVT data of natural gas into the expressions of the first actual gas production data and the first estimated gas production data. Since both the first actual gas production data and the first estimated gas production data are functions of dimensionless pressure, the functional relationship between the ratio of the first actual gas production data to the first estimated gas production data and the dimensionless pressure can be determined by transforming the calculation results according to the functional relationship.

[0096] In this embodiment of the application, before determining the first relationship between the first actual gas production data, the first estimated gas production data, and the dimensionless pressure based on the first actual gas production data and the first estimated gas production data, the method further includes:

[0097] When the gas well is in the boundary control flow stage, the dimensionless gas well production is obtained based on the first actual gas production data and the first estimated gas production data. This is because the gas well production index J in the boundary control flow stage... g The compressibility coefficient c of natural gas under the original formation pressure gi Since it is a constant, only the ratio of integrals remains.

[0098] Dimensionless gas well production meets the following requirements:

[0099]

[0100] q gi,1 This is the initial estimated gas production data at the beginning of the time, in units of 10. 4 m 3 / d;q g,j The first actual gas production data at any given time, in units of 10. 4 m 3 / d;P wD The bottom pressure is dimensionless; P is dimensionless. wD,1 P is the dimensionless bottom hole pressure at the initial moment, which is dimensionless; wD,j p is the dimensionless bottom hole pressure at any given time; λ is the objective parameter; D The pressure is dimensionless and dimensionless. In the embodiments of this application, after the gas well reaches the boundary control flow, J g and c gi Since both are constants, the ratio of the gas well production index to the natural gas compressibility coefficient under the original formation pressure in the above gas well production calculation formula can be simplified, leaving only the integral ratio, to obtain the above dimensionless gas well production.

[0101] S103. Based on the first relationship and the second relationship, determine the relationship between dimensionless pressure and target time. The second relationship represents the relationship between the second actual gas production data, the second estimated gas production data and the target time. The second actual gas production data is the data of the gas well when it is in the boundary control flow stage. Both the second actual gas production data and the second estimated gas production data are determined based on the gas well data.

[0102] The boundary control flow stage, also known as the boundary control flow stage, refers to the stage when a gas well enters a steady state or "quasi-steady state". If the reservoir permeability is low, it generally takes a long time to go from the unstable flow stage to the boundary control flow stage.

[0103] Determining whether a gas well has entered the boundary control flow stage can be based on production data from the gas well under different production operating regimes. In this embodiment, the method prior to determining the relationship between dimensionless pressure and target time based on the first and second relationships may further include:

[0104] Establish a production operation system for gas wells;

[0105] If the gas well maintains a constant bottom pressure for production, then determine the well's decline rate, production time, and actual gas production data.

[0106] Based on the well decline rate, production time, and actual gas production data, a first linear relationship is established between the initial estimated gas production data, actual gas production data, and production time. This first linear relationship is as follows:

[0107] ln(q g )=-D i t+ln(q gi ),

[0108] q g Actual gas production data, unit: 10 4 m 3 / d;q g i represents the initial estimated gas production data, in units of 10. 4 m 3 / d;D i Initial decline rate, unit: day -1 t represents production time, in days.

[0109] If the initial estimated gas production data, the actual gas production data, and the production time satisfy the first linear relationship, then the actual gas production data is determined as the second actual gas production data, and the production time is the target time.

[0110] Among them, D iThis can refer to the initial decline rate of gas well production. The initial decline rate represents the ratio of the gas well's decline rate to the target parameter. The decline rate represents the percentage decrease in production per unit time after a certain period of gas field development, and can be expressed by formula one: The target parameter λ is determined, where D is the decline rate of gas well production, in days. -1 ; t represents time, day; q g This represents the daily gas production of the gas well, in units of 10. 4 m 3 / d. In the embodiments of this application, the formula ln(q) g )=-D i t+ln(q gi We can use the chain rule to differentiate Equation 1 to obtain Equation 2: Formula for gas well production Taking the derivative, we get Formula 3: The dimensionless pressure p D Substitute the mass balance equations of a closed gas reservoir at constant volume Where p is the formation pressure, in MPa; p i The original formation pressure is expressed in MPa; z is the natural gas deviation factor, which is dimensionless. i G is the deviation factor under the original formation pressure, dimensionless; p To accumulate gas production, m 3 G represents cumulative gas production, in m³. 3 And by taking the derivative, we get Formula 4: Substituting Formulas 3 and 4 into Formula 2, and then substituting the resulting relationship into Formula 1, we obtain the formula for the decline rate of a gas well under constant bottom hole pressure: Integrating the formula for the decline rate of a gas well under constant bottom hole pressure yields Formula 5: in, Before the gas well reaches the boundary control flow, the daily gas production q g Rapid decrease; in the early stages of the boundary control flow, the formation pressure decreases very little, λ is close to 1, and β≈1 can be set, so Equation 5 can be transformed into Equation 6: Taking the logarithm of both sides of Equation 6, we can obtain the first linear relationship: ln(q) g )=-D i t+ln(q gi ).

[0111] Where, q gThis refers to the actual gas production data of a gas well, which characterizes the actual gas production data of a gas well under a constant bottom hole pressure production state. It can be determined by real-time measurement of the gas well's production dynamics. Since it is impossible to determine whether the gas well's production capacity has reached stability in actual production conditions, it is possible to determine whether the gas well has reached the boundary control flow stage by determining whether the actual gas production data of the gas well satisfies the first linear relationship. From the first linear relationship, we know that ln(q) g The relationship between t and t is linear, and its slope is -D. i The intercept is ln(q) gi In this embodiment of the application, when the production data of the gas well satisfies the first linear relationship, it is determined that the gas well has entered the boundary control flow stage, and the actual gas production data is determined as the second actual gas production data, and the production time is the target time.

[0112] Where, q gi It can refer to the estimated gas production data when the gas well reaches the boundary control flow stage, that is, the second actual gas production data. The second estimated gas production data can be obtained by extending the relationship curve of the second actual gas production data with time to time 0.

[0113] In this embodiment of the application, the method after determining the production operation system of the gas well may further include:

[0114] If the gas well maintains a constant gas production rate, then determine the bottom hole flowing pressure and production time of the gas well;

[0115] Based on the bottomhole flowing pressure and production time of the gas well, determine whether the bottomhole flowing pressure and production time of the gas well satisfy the second linear relationship, where the second linear relationship is:

[0116]

[0117] Ψ(p wf () represents the simulated bottom hole flowing pressure, in MPa. 2 / (MPa·s); Ψ(p i () represents the original formation pressure and pseudo-pressure, in MPa. 2 / (MPa·s); p sc The pressure under standard conditions; q g Actual gas production data, unit: 10 4 m 3 / d; T is the air layer temperature, unit: K; T sc Temperature under standard conditions; K is gas layer permeability, in mD; h is gas layer thickness, in m; t is production time, in day; φ is porosity, in %; μ is gas viscosity, in MPa·s; C t The overall compressibility factor is expressed in MPa. -1;r w S represents the wellbore radius in meters; S represents the skin factor.

[0118] If the bottom-hole flowing pressure and production time of the gas well do not satisfy the second linear relationship, then the actual gas production data is determined as the second actual gas production data, and the production time is the target time.

[0119] From the second linear relationship, it can be seen that for a gas well with a constant production rate, the bottom hole flowing pressure Ψ(p) under unsteady flow conditions is... wf The flow rate is linearly related to lgt. Therefore, the moment when the flow rate deviates from the linear relationship is the starting point of the boundary control flow. Thus, if the bottom hole flow pressure and production time of the gas well do not satisfy the second linear relationship, the actual gas production data is determined as the second actual gas production data, and the production time is the target time.

[0120] In this embodiment of the application, the method prior to determining the relationship between dimensionless pressure and target time based on the first relationship and the second relationship may further include:

[0121] Determine the relationship between the second actual gas production data and time;

[0122] A relationship curve is generated based on the relationship between the second actual gas production data and time.

[0123] The relationship curve is fitted to obtain the target relationship curve;

[0124] Based on the target relationship curve, determine the second estimated gas production data;

[0125] Determine the second relationship between the second actual gas production data, the second estimated gas production data, and the target time.

[0126] The second actual gas production data can refer to the gas production data points of the gas well that have reached the boundary control flow stage selected from the actual production dynamic data of the gas well. The gas production data obtained by fitting the relationship curve of the gas well production data points according to the target time and extending it to the initial time (time 0) is the second estimated gas production data. The target time can refer to the time after the selected gas well reaches the boundary control flow stage within the gas well production time.

[0127] The first actual gas production data and the second actual gas production data, as well as the first estimated gas production data and the second estimated gas production data, can be the same or different. Whether they are the same depends on the actual production situation. When the gas well maintains a constant bottom hole pressure or a constant gas production and reaches the boundary control flow stage, the same conditions are met, and the two are the same.

[0128] The second relationship can refer to the relationship function obtained by comparing the ratio of the actual gas production data obtained from the actual gas production data when the gas well reaches the boundary control flow stage with the relationship curve of the fitted gas production data points according to the target time, and the target time.

[0129] Based on the first and second relationships, the relationship between dimensionless pressure and target time can be determined by the relationship between the first actual gas production data, the first estimated gas production data and the dimensionless pressure represented by the first relationship, and the relationship between the second actual gas production data, the second estimated gas production data and the target time represented by the second relationship. Thus, the relationship between dimensionless pressure and target time can be transformed based on the functional relationship between the various data.

[0130] S104. Based on the relationship between dimensionless pressure and target time, and the cumulative gas production data, determine the dynamic reserves of the gas well.

[0131] The cumulative gas production data can refer to the sum of the cumulative gas production of each well point in the gas reservoir. In the embodiments of this application, the cumulative gas production data can refer to the gas production of the gas well within a target time period, and the cumulative gas production data of the gas well is known under standard conditions.

[0132] Determining the dynamic reserves of a gas well based on the relationship between dimensionless pressure and target time, and the cumulative gas production data, can be achieved by transforming the functional relationships between dimensionless pressure and target time, and between cumulative gas production data and target time. This yields the relationship between dimensionless pressure and cumulative gas production data. According to the material balance equation for a constant-volume closed gas reservoir, there is a linear relationship between formation pressure and cumulative gas production data. Furthermore, dimensionless pressure is a function of formation pressure. Therefore, a linear relationship curve between dimensionless pressure and cumulative gas production data can be fitted, and the intersection of this curve with the horizontal axis represents the dynamic reserves of the gas well.

[0133] The material balance equation for a closed gas reservoir with constant volume is:

[0134]

[0135] p is the formation pressure, in MPa; i The original formation pressure is expressed in MPa; z is the natural gas deviation factor, which is dimensionless. i G is the deviation factor under the original formation pressure, dimensionless; p To accumulate gas production, m 3 G represents cumulative gas production, in m³. 3 .

[0136] In this embodiment of the application, the method after determining the relationship between dimensionless pressure and target time based on the first relationship and the second relationship may further include:

[0137] Based on the relationship between dimensionless pressure and target time, the relationship between formation pressure and target time is obtained;

[0138] The average formation pressure of the gas well is determined based on the relationship between formation pressure and target time.

[0139] Among them, the average formation pressure of a gas well, determined based on the relationship between formation pressure and target time, can refer to the pressure that is dimensionless and satisfies the following:

[0140]

[0141] p represents formation pressure in MPa; z is the natural gas deviation factor, dimensionless; p i Original formation pressure, unit: MPa; z i Let p be the natural gas deviation factor under the original formation pressure, which is dimensionless. Therefore, the dimensionless pressure is a function of the formation pressure, and the dimensionless pressure p can be expressed as... D The pressure is converted to formation pressure p. Based on the relationship between dimensionless pressure and target time, the variation law of formation pressure with target time is obtained, and the average formation pressure of the gas well is calculated.

[0142] The explicit method for determining the dynamic reserves of gas wells provided in this application can derive the dimensionless gas well production calculation formula for the boundary control flow stage based on the relationship between target parameters and dimensionless pressure, combined with the gas well production calculation formula for a constant-volume closed gas reservoir. Then, based on PVT data under different pressures, it derives the first relationship between the ratio of the first actual gas production data to the first estimated gas production data and the dimensionless pressure, and the second relationship between the ratio of the second actual gas production data to the second estimated gas production data and the target time. Finally, it determines the relationship between the dimensionless pressure and the target time based on the first and second relationships, and combines the relationship between the cumulative gas production data and the target time to obtain the linear relationship between the dimensionless pressure and the cumulative gas production data, thus obtaining the dynamic reserves of the gas well. Therefore, by transforming the relationships between various parameters, it avoids the problem of cumbersome calculations caused by numerous unknowns in existing reserve calculation formulas. Furthermore, it uses only dynamic production data to obtain the predicted gas production without shutting in the well, thereby avoiding iterative calculations of pseudo-time and pseudo-pressure functions. The dynamic reserves of the gas well can be obtained simply by observing the relationship curves.

[0143] Figure 2 A flowchart illustrating another method for explicitly determining the dynamic reserves of a gas well, provided as an embodiment of this application. Figure 2 As shown, with the server as the execution entity, the method in this embodiment may include the following steps:

[0144] S201. Determine the reservoir temperature and natural gas specific gravity.

[0145] S202. Based on the reservoir temperature and natural gas specific gravity, calculate the variation of PVT parameters with bottom hole pressure.

[0146] S203. Based on the calculation methods of target parameters and dimensionless pressure, and combined with the law of PVT parameter variation with bottom hole pressure, calculate the relationship between target parameters and dimensionless pressure.

[0147] Among them, the target parameter λ and the dimensionless pressure p D The calculation method can be obtained based on the gas well production calculation formula:

[0148]

[0149] q g Actual gas production data, unit: 10 4 m 3 / d;J g Gas well production index, unit: 10 4 m 3 / d / MPa;c gi The compressibility coefficient of natural gas under the original formation pressure, in MPa. -1 ;p D For dimensionless pressure, dimensionless; P wD λ represents the dimensionless bottom hole pressure, which is dimensionless; λ is the target parameter.

[0150] The target parameters satisfy:

[0151]

[0152] μ g Natural gas viscosity, unit: MPa·s; c g The compressibility factor of natural gas, in MPa. -1 μ gi The viscosity of natural gas under the original formation pressure, in MPa·s; c gi The compressibility coefficient of natural gas under the original formation pressure, in MPa. -1 .

[0153] Dimensionless pressure satisfaction:

[0154]

[0155] p represents formation pressure in MPa; z is the natural gas deviation factor, dimensionless; p i Original formation pressure, unit: MPa; z i This is the natural gas deviation factor under the original formation pressure, and it is dimensionless.

[0156] Dimensionless bottom hole pressure satisfies:

[0157]

[0158] p wf Bottom hole flowing pressure, unit: MPa; z wf p is the deviation factor under bottom hole pressure, dimensionless; i Original formation pressure, unit: MPa; z i It is the deviation factor under the original formation pressure, and is dimensionless.

[0159] Based on the above relationship, it can be seen that the target parameter λ is a function of the PVT parameters, and the dimensionless pressure p D It is a function of formation pressure. Based on the variation of PVT parameters with bottom hole pressure obtained in S202, the target parameter λ and the dimensionless pressure p can be derived. D The relationship between them.

[0160] S204. Based on the actual production data of the gas well, fit the relationship curve between the daily gas production of the gas well and time in the boundary control flow stage to obtain the initial daily gas production of the gas well.

[0161] The initial daily gas production of a gas well can refer to the data obtained by estimating the daily gas production of a gas well at the initial moment based on the daily gas production of the gas well during the boundary control flow stage. The value can be determined by extending the fitted curve of the relationship between the daily gas production of the gas well during the boundary control flow stage and time to time 0.

[0162] S205. Calculate the relationship between the daily gas production of the gas well / the initial daily gas production of the gas well and time, based on the actual production data of the gas well and the initial daily gas production of the gas well.

[0163] S206. Based on the PVT parameters of natural gas, actual production data, and the initial daily gas production of the gas well, calculate the relationship between the daily gas production of the gas well / the initial daily gas production of the gas well and the dimensionless pressure.

[0164] The relationship between calculating the daily gas production of a gas well / the initial daily gas production of a gas well and the dimensionless pressure can be achieved by defining a dimensionless gas well production formula based on the initial daily gas production formula of the boundary control flow, and then substituting the PVT parameters of natural gas, actual production data, and the initial daily gas production of the gas well into the dimensionless gas well production formula for calculation, thereby determining the relationship between the parameters.

[0165] The formula for the initial daily gas production of the boundary control flow is:

[0166]

[0167] The initial daily gas production formula for boundary control flow is a special case of the gas well production formula. It is the production calculation formula for a gas well in the boundary control flow stage. Because the gas well in the boundary control flow stage has no dimensionless pressure p DIf the value is 1, then the upper limit of integration is 1, resulting in the above formula.

[0168] The formula for dimensionless gas well production is:

[0169]

[0170] q gi,1 This is the estimated gas production data at the initial moment, in units of 10. 4 m 3 / d;q g,j Actual gas production data at different times, unit: 10 4 m 3 / d;P wD The bottom pressure is dimensionless; P is dimensionless. wD,1 P is the dimensionless bottom hole pressure at the initial moment, which is dimensionless; wD,j p represents the dimensionless bottom hole pressure at different times; λ is the objective parameter; D For dimensionless pressure, dimensionless.

[0171] Based on the ratio definition of the above relationship, a dimensionless gas well production formula is defined, since the gas well production index J in the boundary control flow stage... g The compressibility coefficient c of natural gas under the original formation pressure gi Since it is a constant, only the ratio of integrals remains.

[0172] S207. From the relationship between the daily gas production of the gas well / the initial daily gas production of the gas well and the dimensionless pressure, and the relationship between the daily gas production of the gas well / the initial daily gas production of the gas well and time, we can obtain the relationship between the dimensionless pressure and time, as well as the average formation pressure of the gas well.

[0173] Among them, according to the dimensionless pressure p D The relationship with time t can be used to measure the dimensionless pressure p. D The pressure is converted into formation pressure p, and the relationship between formation pressure p and time t is obtained. The variation law of formation pressure with time is determined, and the average formation pressure of the gas well is obtained.

[0174] S208. Based on the relationship between the daily gas production of the gas well / the initial daily gas production of the gas well, time, and dimensionless pressure, determine the linear relationship between dimensionless pressure and cumulative gas production, as well as the dynamic reserves of the gas well.

[0175] Among them, based on the daily gas production of the gas well / the initial daily gas production of the gas well q g / q gi Time t, and dimensionless pressure p D The relationship between them determines the dimensionless pressure p. D With cumulative gas production G pThe linear relationship between them can refer to obtaining the cumulative gas production G based on the dimensionless gas well production formula and time. p The relationship with time t allows us to determine the dimensionless pressure p. D With cumulative gas production G p The linear relationship between the two is such that the intersection of the straight line on the horizontal axis represents the dynamic reserves of the gas well.

[0176] This embodiment provides another explicit method for determining the dynamic reserves of gas wells. By deriving the initial daily gas production formula for the boundary control flow, defining the dimensionless gas well production formula, transforming the relationship between various parameters, and using relevant functional relationships, the influence of unknown parameters is eliminated. Thus, it solves the problems of poor adaptability and cumbersome calculation in current reserve calculation methods.

[0177] When the original formation pressure in the gas well area is 23.32 MPa, the reservoir temperature is 75℃, and the natural gas specific gravity is 0.65, the production history of this gas well is as follows: Figure 3 As shown, both daily gas production and bottom hole pressure changed.

[0178] Using the method for displaying and determining the dynamic reserves of gas wells provided in this application, the dimensionless pressure p is obtained. D With cumulative gas production G p The relationship between them, such as Figure 4 As shown, the two exhibit a clear linear relationship, yielding geological reserves G = 7680 × 10⁻⁶. 4 m 3 .

[0179] Since the embodiments of this application use explicit linear analysis, the results are more intuitive, and the fitting data uses data from gas wells in the boundary control flow stage, thus the reliability is stronger.

[0180] Figure 5 A schematic diagram of the structure of the explicit determination device for dynamic gas well reserves provided in an embodiment of this application. Figure 5 As shown, the explicit determination device 50 for the dynamic reserves of the gas well includes: a first determination module 501, a second determination module 502, a third determination module 503, and a fourth determination module 504. Wherein:

[0181] The first determining module 501 is used to determine the first actual gas production data and the first estimated gas production data of the gas well. The first actual gas production data is obtained by integrating the target parameters based on the dimensionless pressure and dimensionless bottom hole pressure of the gas well. The first estimated gas production data is obtained by integrating the target parameters based on the dimensionless bottom hole pressure and the target dimensionless pressure. The target parameters are determined based on the natural gas viscosity and natural gas compressibility coefficient in the PVT data under different pressures. The dimensionless pressure is determined based on the natural gas deviation factor and formation pressure in the PVT data under different pressures.

[0182] The second determining module 502 is used to determine the first relationship between the first actual gas production data, the first estimated gas production data and the dimensionless pressure based on the first actual gas production data and the first estimated gas production data.

[0183] The third determining module 503 is used to determine the relationship between dimensionless pressure and target time based on the first relationship and the second relationship. The second relationship represents the relationship between the second actual gas production data, the second estimated gas production data and the target time. The second actual gas production data is the data of the gas well when it is in the boundary control flow stage. Both the second actual gas production data and the second estimated gas production data are determined based on the gas well data.

[0184] The fourth determination module 504 is used to determine the dynamic reserves of the gas well based on the relationship between dimensionless pressure and target time and the cumulative gas production data.

[0185] In this embodiment of the application, the first determining module 501 may also be specifically used for:

[0186] Determine the viscosity and compressibility of natural gas in PVT data under different pressures;

[0187] Based on the natural gas viscosity and compressibility coefficient from PVT data under different pressures, the target parameters are obtained, whereby the target parameters satisfy:

[0188]

[0189] μ g Natural gas viscosity, unit: MPa·s; c g The compressibility factor of natural gas, in MPa. -1 μ gi The viscosity of natural gas under the original formation pressure, in MPa·s; c gi The compressibility coefficient of natural gas under the original formation pressure, in MPa. -1 .

[0190] In this embodiment of the application, the first determining module 501 may also be specifically used for:

[0191] Determine the natural gas deviation factor in PVT data under different pressures;

[0192] Based on the natural gas deviation factor in the PVT data under different pressures, the dimensionless pressure is obtained, where the dimensionless pressure satisfies:

[0193]

[0194] p represents formation pressure in MPa; z is the natural gas deviation factor, dimensionless; p i Original formation pressure, unit: MPa; z i This is the natural gas deviation factor under the original formation pressure, and it is dimensionless.

[0195] In this embodiment of the application, the second determining module 502 may also be specifically used for:

[0196] When the gas well is in the boundary control flow stage, the dimensionless gas well production is obtained based on the first actual gas production data and the first estimated gas production data, wherein the dimensionless gas well production satisfies:

[0197]

[0198] Where, q gi,1 This is the initial estimated gas production data at the beginning of the time, in units of 10. 5 m 3 / d;q g,j The first actual gas production data at any given time, in units of 10. 5 m 3 / d;P wD The bottom pressure is dimensionless; P is dimensionless. wD,1 P is the dimensionless bottom hole pressure at the initial moment, which is dimensionless; wD,j p is the dimensionless bottom hole pressure at any given time; λ is the objective parameter; D For dimensionless pressure, dimensionless.

[0199] In this embodiment of the application, the third determining module 503 may also be specifically used for:

[0200] Establish a production operation system for gas wells;

[0201] If the gas well maintains a constant bottom pressure for production, then determine the well's decline rate, production time, and actual gas production data.

[0202] Based on the well decline rate, production time, and actual gas production data, a first linear relationship is established between the initial estimated gas production data, actual gas production data, and production time. This first linear relationship is as follows:

[0203] ln(qg )=-D i t+ln(q gi ),

[0204] q g Actual gas production data, unit: 10 5 m 3 / d;q gi Initial estimated gas production data, unit: 10 5 m 3 / d;D i Initial decline rate, unit: day -1 t represents production time, in days.

[0205] If the initial estimated gas production data, the actual gas production data, and the production time satisfy the first linear relationship, then the actual gas production data is determined as the second actual gas production data, and the production time is the target time.

[0206] In this embodiment of the application, the third determining module 503 may also be specifically used for:

[0207] If the gas well maintains a constant gas production rate, then determine the bottom hole flowing pressure and production time of the gas well;

[0208] Based on the bottomhole flowing pressure and production time of the gas well, determine whether the bottomhole flowing pressure and production time of the gas well satisfy the second linear relationship, where the second linear relationship is:

[0209]

[0210] Ψ(p wf () represents the bottom hole flowing pressure, in MPa. 2 / (MPa·s); Ψ(p i () represents the original formation pressure and pseudo-pressure, in MPa. 2 / (MPa·s); p sc The pressure under standard conditions; q g Actual gas production data, unit: 10 5 m 3 / d; T is the air layer temperature, unit: K; T sc Temperature under standard conditions; K is gas layer permeability, in mD; h is gas layer thickness, in m; t is production time, in day; φ is porosity, in %; μ is gas viscosity, in MPa·s; C t The overall compressibility factor is expressed in MPa. -1 ;r w S represents the wellbore radius in meters; S represents the skin factor.

[0211] If the bottom-hole flowing pressure and production time of the gas well do not satisfy the second linear relationship, then the actual gas production data is determined as the second actual gas production data, and the production time is the target time.

[0212] In this embodiment of the application, the third determining module 503 may also be specifically used for:

[0213] Determine the relationship between the second actual gas production data and time;

[0214] A relationship curve is generated based on the relationship between the second actual gas production data and time.

[0215] The relationship curve is fitted to obtain the target relationship curve;

[0216] Based on the target relationship curve, determine the second estimated gas production data;

[0217] Determine the second relationship between the second actual gas production data, the second estimated gas production data, and the target time.

[0218] In this embodiment of the application, the fourth determining module 504 can also be specifically used for:

[0219] Based on the relationship between dimensionless pressure and target time, the relationship between formation pressure and target time is obtained;

[0220] The average formation pressure of the gas well is determined based on the relationship between formation pressure and target time.

[0221] The explicit determination device 50 for dynamic gas well reserves provided in this application embodiment can execute the above method embodiment. Its specific implementation principle and technical effects can be found in the above method embodiment, and will not be repeated here.

[0222] In some embodiments, a computer program product is also provided, including a computer program or instructions that, when executed by a processor, implement the steps in any of the above-described methods for explicitly determining the dynamic reserves of a gas well.

[0223] For details on the implementation of each of the above operations, please refer to the previous examples, which will not be repeated here.

[0224] Those skilled in the art will understand that all or part of the steps in the various methods of the above embodiments can be performed by instructions, or by instructions controlling related hardware. These instructions can be stored in a computer-readable storage medium and loaded and executed by a processor.

[0225] Therefore, embodiments of this application provide a computer-readable storage medium storing a plurality of instructions that can be loaded by a processor to execute steps in any of the explicit methods for determining dynamic reserves of gas wells provided in embodiments of this application.

[0226] The storage medium may include: read-only memory (ROM), random access memory (RAM), disk or optical disk, etc.

[0227] According to one aspect of this application, a computer program product or computer program is provided, the computer program product or computer program including computer-executable instructions stored in a computer-readable storage medium.

[0228] Since the instructions stored in the storage medium can execute the steps in any of the explicit determination methods for dynamic gas well reserves provided in the embodiments of this application, the beneficial effects that any of the explicit determination methods for dynamic gas well reserves provided in the embodiments of this application can achieve can be realized, as detailed in the preceding embodiments, and will not be repeated here.

[0229] Other embodiments of this application will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of this application that follow the general principles of this application and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of this application are indicated by the following claims.

[0230] It should be understood that this application is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this application is limited only by the appended claims.

Claims

1. A method for explicitly determining the dynamic reserves of a gas well, characterized in that, An explicit method for determining dynamic reserves in gas wells includes: The first actual gas production data and the first estimated gas production data of the gas well are determined. The first actual gas production data is obtained by integrating the target parameters based on the dimensionless pressure and dimensionless bottom hole pressure of the gas well. The first estimated gas production data is obtained by integrating the target parameters based on the dimensionless bottom hole pressure and the target dimensionless pressure. The target parameters are determined based on the natural gas viscosity and natural gas compressibility coefficient in the PVT data under different pressures. The dimensionless pressure is determined based on the natural gas deviation factor and formation pressure in the PVT data under different pressures. Based on the first actual gas production data and the first estimated gas production data, a first relationship is determined between the first actual gas production data, the first estimated gas production data and the dimensionless pressure. The first relationship characterizes the relationship between the ratio of the first actual gas production data to the first estimated gas production data and the dimensionless pressure. Based on the first relationship and the second relationship, the relationship between the dimensionless pressure and the target time is determined, wherein the second relationship characterizes the relationship between the ratio of the second actual gas production data to the second estimated gas production data and the target time, the second actual gas production data is the data of the gas well in the boundary control flow stage, and both the second actual gas production data and the second estimated gas production data are determined based on the gas well data of the gas well. Based on the relationship between the dimensionless pressure and the target time, and combined with the relationship between the cumulative gas production data and the target time, a linear relationship between the dimensionless pressure and the cumulative gas production data is obtained, and the dynamic reserves of the gas well are determined. Before determining the first actual gas production data and the first estimated gas production data of the gas well, the method further includes: Determine the natural gas viscosity and natural gas compressibility coefficient in the PVT data under different pressures; Based on the natural gas viscosity and compressibility coefficient in the PVT data under different pressures, target parameters are obtained, wherein the target parameters satisfy: ， The viscosity of natural gas is expressed in MPa·s. The compressibility factor of natural gas, in MPa. -1 ; The viscosity of natural gas under the original formation pressure, in MPa·s; The compressibility coefficient of natural gas under the original formation pressure, in MPa. -1 ; Before determining the relationship between the dimensionless pressure and the target time based on the first and second relationships, the method further includes: Determine the relationship between the second actual gas production data and time; Based on the relationship between the second actual gas production data and time, a relationship curve is generated; The relationship curve is fitted to obtain the target relationship curve; Based on the target relationship curve, determine the second estimated gas production data; Determine a second relationship between the second actual gas production data, the second estimated gas production data, and the target time.

2. The method according to claim 1, characterized in that, Before determining the first actual gas production data and the first estimated gas production data of the gas well, the method further includes: Determine the natural gas deviation factor in the PVT data under different pressures; Based on the natural gas deviation factor in the PVT data under different pressures, the dimensionless pressure is obtained, wherein the dimensionless pressure satisfies: ， Formation pressure, unit: MPa; This is the natural gas deviation factor, which is dimensionless. Original formation pressure, unit: MPa; This is the natural gas deviation factor under the original formation pressure, and it is dimensionless.

3. The method according to claim 1, characterized in that, Before determining the first relationship between the first actual gas production data, the first estimated gas production data, and the dimensionless pressure based on the first actual gas production data and the first estimated gas production data, the method further includes: When the gas well is in the boundary control flow stage, the dimensionless gas well production is obtained based on the first actual gas production data and the first estimated gas production data, wherein the dimensionless gas well production satisfies: ， in, This is the initial estimated gas production data at the beginning of the time, in units of 10. 4 m 3 / d; The first actual gas production data at any given time, in units of 10. 4 m 3 / d; The bottom pressure is dimensionless and dimensionless. Let be the dimensionless bottom hole pressure at the initial moment, which is dimensionless; Let be the dimensionless bottom hole pressure at any given time, which is dimensionless; For target parameters; For dimensionless pressure, dimensionless.

4. The method according to claim 1, characterized in that, Before determining the relationship between the dimensionless pressure and the target time based on the first and second relationships, the method further includes: Determine the production operation system for the gas well; If the gas well maintains constant bottom pressure production, then determine the well's decline rate, production time, and actual gas production data; Based on the decline rate, production time, and actual gas production data of the gas well, a first linear relationship is determined between the initial estimated gas production data, the actual gas production data, and the production time, wherein the first linear relationship is: ， Actual gas production data, unit: 10 4 m 3 / d; Initial estimated gas production data, unit: 10 4 m 3 / d; Initial decline rate, unit: day -1 ; Production time, unit: day; If the initial estimated gas production data, the actual gas production data, and the production time satisfy the first linear relationship, then the actual gas production data is determined to be the second actual gas production data, and the production time is the target time.

5. The method according to claim 4, characterized in that, After determining the production operating regime of the gas well, the method further includes: If the gas well maintains a constant gas production rate, then the bottom hole flowing pressure and production time of the gas well are determined. Based on the bottom hole flowing pressure and production time of the gas well, determine whether the bottom hole flowing pressure and production time of the gas well satisfy a second linear relationship, wherein the second linear relationship is: ， The simulated pressure at the bottom of the well is expressed in MPa. 2 / (MPa·s); The original formation pressure is the pseudo-pressure, in MPa. 2 / (MPa·s); Pressure under standard conditions; Actual gas production data, unit: 10 4 m 3 / d; T is the air layer temperature, unit: K; Temperature under standard conditions; K is the gas layer permeability, in mD; h is the gas layer thickness, in m. Production time, unit: day; Porosity, unit: % The viscosity is expressed as MPa·s. The overall compressibility factor is expressed in MPa. -1 ; S represents the wellbore radius in meters; S represents the skin factor. If the bottom-hole flowing pressure and production time of the gas well do not satisfy the second linear relationship, then the actual gas production data is determined to be the second actual gas production data, and the production time is the target time.

6. The method according to claim 1, characterized in that, After determining the relationship between the dimensionless pressure and the target time based on the first and second relationships, the method further includes: Based on the relationship between dimensionless pressure and target time, the relationship between formation pressure and target time is obtained; The average formation pressure of the gas well is determined based on the relationship between the formation pressure and the target time.

7. A device for explicitly determining the dynamic reserves of a gas well, characterized in that, The device includes: The first determining module is used to determine the first actual gas production data and the first estimated gas production data of the gas well. The first actual gas production data is obtained by integrating the target parameters based on the dimensionless pressure and dimensionless bottom hole pressure of the gas well. The first estimated gas production data is obtained by integrating the target parameters based on the dimensionless bottom hole pressure and the target dimensionless pressure. The target parameters are determined based on the natural gas viscosity and natural gas compressibility coefficient in the PVT data under different pressures. The dimensionless pressure is determined based on the natural gas deviation factor and formation pressure in the PVT data under different pressures. The second determining module is used to determine a first relationship between the first actual gas production data, the first estimated gas production data and the dimensionless pressure based on the first actual gas production data and the first estimated gas production data. The first relationship characterizes the relationship between the ratio of the first actual gas production data to the first estimated gas production data and the dimensionless pressure. The third determining module is used to determine the relationship between the dimensionless pressure and the target time based on the first relationship and the second relationship, wherein the second relationship characterizes the relationship between the ratio of the second actual gas production data to the second estimated gas production data and the target time, the second actual gas production data is the data of the gas well in the boundary control flow stage, and both the second actual gas production data and the second estimated gas production data are determined based on the gas well data of the gas well. The fourth determining module is used to determine the dynamic reserves of the gas well by obtaining the linear relationship between the dimensionless pressure and the cumulative gas production data based on the relationship between the dimensionless pressure and the target time, combined with the relationship between the cumulative gas production data and the target time. The first determining module is further configured to determine the natural gas viscosity and natural gas compressibility coefficient in the PVT data under different pressures; Based on the natural gas viscosity and compressibility coefficient in the PVT data under different pressures, target parameters are obtained, wherein the target parameters satisfy: ， The viscosity of natural gas is expressed in MPa·s. The compressibility factor of natural gas, in MPa. -1 ; The viscosity of natural gas under the original formation pressure, in MPa·s; The compressibility coefficient of natural gas under the original formation pressure, in MPa. -1 ; The third determining module is also used to determine the relationship between the second actual gas production data and time. Based on the relationship between the second actual gas production data and time, a relationship curve is generated; The relationship curve is fitted to obtain the target relationship curve; Based on the target relationship curve, determine the second estimated gas production data; Determine a second relationship between the second actual gas production data, the second estimated gas production data, and the target time.

8. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer-executable instructions, which, when executed by a processor, are used to implement the explicit method for determining the dynamic reserves of a gas well as described in any one of claims 1 to 6.

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