Horizontal well plunger lifting liquid leakage flow prediction and regulation method and device

Abstract

The application discloses a horizontal well plunger lifting liquid leakage flow prediction and regulation method and device, and relates to the technical field of oil and gas field exploitation. The liquid leakage flow is determined based on a first parameter; the top liquid column height of a current time step and the driving pressure difference of the current time step are determined based on a second parameter and the liquid leakage flow; the determined driving pressure difference of the current time step and the plunger speed of the current time step are used for convergence judgment; the top liquid column height of a next time step is determined based on the liquid leakage flow, the top liquid column height of the current time step, a time step length and a tubing inner diameter; the plunger displacement of the current time step is determined based on the plunger speed of the current time step and the time step length, and if the plunger displacement of the current time step is greater than or equal to the depth of a downhole sitter, the parameter determination step is terminated; and the throttle valve opening is adjusted based on a regulation parameter. The method solves the problem that the prior art relies on experience parameters, resulting in low efficiency and poor stability of horizontal well plunger lifting process design.

Description

Technical Field

[0001] This application relates to the field of oil and gas field development technology, and in particular to a method and device for predicting and controlling the leakage flow of liquid in a horizontal well plunger lift. Background Technology

[0002] The plunger lifting technology is widely used as a core method for drainage and gas production in oil and gas fields, and it plays an irreplaceable role in enhancing efficiency, especially in high water-cut gas wells and low-pressure, low-production wells.

[0003] However, the liquid loss and gas surge phenomena commonly encountered during the gas lift plunger process limit the plunger's liquid-carrying efficiency. To optimize the liquid-carrying efficiency of gas lift plungers, research on the gas-liquid leakage characteristics of plunger lifts in vertical wells has been relatively in-depth and comprehensive. However, methods for predicting leakage flow in horizontal wells remain lacking, especially dynamic prediction methods for leakage flow at different well inclination angles. Furthermore, existing technologies heavily rely on empirical parameters, making it difficult to quantify the dynamic changes in leakage flow and driving pressure differential in real time. This results in low efficiency and poor stability in the design of horizontal well plunger lift processes, severely limiting their widespread application. Summary of the Invention

[0004] In this embodiment of the application, a method for predicting and controlling the leakage flow rate of liquid in horizontal well plunger lifting is provided, which solves the problem that the existing technology relies heavily on empirical parameters and is difficult to quantify the dynamic changes of leakage flow rate and driving pressure difference in real time, resulting in low efficiency and poor stability of horizontal well plunger lifting process design.

[0005] In a first aspect, embodiments of this application provide a method for predicting and controlling the fluid leakage flow rate of a horizontal well plunger lift. The method includes: setting a time step, initializing the plunger velocity and driving pressure difference to obtain an initial plunger velocity and an initial driving pressure difference, and executing a parameter determination step and a parameter update step. The parameter determination step includes: determining the fluid leakage flow rate of the horizontal well plunger lift based on a first parameter; determining the top liquid column height and the driving pressure difference of the current time step based on a second parameter and the fluid leakage flow rate; determining the plunger velocity of the current time step based on Newton's second law; performing a convergence judgment using the determined driving pressure difference and plunger velocity of the current time step; if the convergence condition is met, outputting the driving pressure difference and plunger velocity of the current time step; if the convergence condition is not met, assigning the driving pressure difference of the current time step to the initial driving pressure difference, assigning the plunger velocity of the current time step to the initial plunger velocity, and iteratively executing the parameter determination step until the convergence condition is met. The parameter update step is performed based on the fluid leakage flow rate when the convergence condition is met, the top liquid column height at the current time step, and the time step length. This includes: determining the top liquid column height for the next time step based on the fluid leakage flow rate, the top liquid column height at the current time step, the time step length, and the tubing inner diameter; determining the plunger displacement at the current time step based on the plunger velocity and the time step length; if the plunger displacement at the current time step is greater than or equal to the bottom hole landing device depth, terminating the parameter determination step; otherwise, using the plunger velocity and driving pressure difference at the current time step as the initial plunger velocity and initial driving pressure difference for the next time step, and iteratively performing the parameter determination step based on the top liquid column height at the next time step until the plunger displacement at the current time step is greater than or equal to the bottom hole landing device depth; and transmitting the output driving pressure difference and fluid leakage flow rate at the current time step as control parameters to the well site control system, which adjusts the wellhead choke valve opening in real time based on the control parameters.

[0006] In one possible implementation, the first parameter includes: initial plunger velocity, initial driving pressure differential, tubing inner diameter, well inclination angle, wellbore curvature, plunger outer diameter, and plunger length; determining the fluid leakage flow rate of the horizontal well plunger lift based on the first parameter includes: ;in, The fluid leakage flow rate during horizontal well plunger lifting. The inner diameter of the oil pipe. The gap height, For liquid viscosity, To drive the pressure difference, For the plunger length, For the density of the liquid, It is the acceleration due to gravity. The well inclination angle, For the eccentricity, The piston speed; ;in, For the plunger mass, The outer diameter of the plunger. For wellbore curvature, For plunger stiffness; .

[0007] In one possible implementation, the second parameter includes: leakage flow rate, tubing inner diameter, well inclination angle, wellhead oil pressure, wellhead casing pressure, and bottom hole placement device depth; the expression for determining the driving pressure difference at the current time step is: ;in, The driving pressure difference at the current time step. The driving pressure difference of the previous time step. This refers to the pressure change at the top of the plunger. This refers to the pressure change at the bottom of the plunger; ;in, For mixed density, The height is calculated for the upward movement of gas. The height is calculated based on the liquid leakage. , The gas leakage flow rate during horizontal well plunger lifting. For plunger lifting time , The fluid leakage flow rate during horizontal well plunger lifting; ;in, For gas viscosity, Density of natural gas; ; ;in, This refers to the gas content of the liquid column at the top of the plunger. For the density of natural gas, , Here is the height of the top liquid column; the expression for the height of the top liquid column at the current time step is: ;in, This is the height of the top liquid column. For wellhead casing pressure, For wellhead oil pressure, This refers to the depth of the well bottom positioning device.

[0008] In one possible implementation, determining the piston velocity at the current time step based on Newton's second law includes: constructing a dynamic equation for piston lifting based on Newton's second law, and solving for acceleration in the dynamic equation; determining the piston velocity at the current time step based on the acceleration, wherein the expression for the piston velocity at the current time step is: ;in, The piston speed at the current time step. The piston speed in the previous time step. For acceleration, For time step.

[0009] In one possible implementation, determining the top liquid column height for the next time step based on the liquid leakage flow rate, the top liquid column height at the current time step, the time step length, and the tubing inner diameter includes: ;in, The height of the top liquid column at the next time step. The fluid leakage flow rate during horizontal well plunger lifting. This represents the height of the top liquid column at the current time step. For time step, This refers to the inner diameter of the oil pipe.

[0010] In one possible implementation, determining the piston displacement at the current time step based on the piston speed and time step size at the current time step includes: ;in, This represents the piston displacement at the current time step. This represents the piston displacement in the previous time step. The piston speed at the current time step. For time step.

[0011] In one possible implementation, the convergence condition is: the ratio of the difference between the driving pressure differential of the current time step and the driving pressure differential of the previous time step to the driving pressure differential of the previous time step is less than 0.1%, and the ratio of the difference between the piston speed of the current time step and the piston speed of the previous time step to the piston speed of the previous time step is less than 0.1%.

[0012] Secondly, embodiments of this application provide a device for predicting and controlling the fluid leakage flow rate of a horizontal well plunger lift. The device includes: an execution module, configured to set a time step, initialize the plunger velocity and driving pressure difference to obtain an initial plunger velocity and an initial driving pressure difference, and execute a parameter determination step and a parameter update step; a parameter determination module, configured to determine the fluid leakage flow rate of the horizontal well plunger lift based on a first parameter; determine the top liquid column height and the driving pressure difference of the current time step based on a second parameter and the fluid leakage flow rate; determine the plunger velocity of the current time step based on Newton's second law; perform a convergence judgment using the determined driving pressure difference and plunger velocity of the current time step; if the convergence condition is met, output the driving pressure difference and plunger velocity of the current time step; if the convergence condition is not met, assign the driving pressure difference of the current time step to the initial driving pressure difference, assign the plunger velocity of the current time step to the initial plunger velocity, and iteratively execute the parameter determination step until the convergence condition is met; The parameter update module performs the parameter update steps based on the liquid leakage flow rate when the convergence condition is met, the top liquid column height at the current time step, and the time step length. This includes: determining the top liquid column height for the next time step based on the liquid leakage flow rate, the top liquid column height at the current time step, the time step length, and the tubing inner diameter; determining the plunger displacement at the current time step based on the plunger velocity and the time step length; if the plunger displacement at the current time step is greater than or equal to the bottom hole seat depth, terminating the parameter determination step; otherwise, using the plunger velocity and driving pressure difference at the current time step as the initial plunger velocity and initial driving pressure difference for the next time step, and iteratively performing the parameter determination steps based on the top liquid column height at the next time step until the plunger displacement at the current time step is greater than or equal to the bottom hole seat depth; and transmitting the output driving pressure difference and liquid leakage flow rate at the current time step as control parameters to the well site control system, which adjusts the wellhead choke valve opening in real time based on the control parameters.

[0013] Thirdly, embodiments of this application provide a horizontal well plunger lifting fluid leakage flow prediction and control server, including a memory and a processor; the memory is used to store computer-executable instructions; the processor is used to execute the computer-executable instructions to implement the method described in the first aspect or any possible implementation of the first aspect.

[0014] Fourthly, embodiments of this application provide a computer-readable storage medium storing executable instructions, which, when executed by a computer, enable the method described in the first aspect or any possible implementation thereof.

[0015] One or more technical solutions provided in the embodiments of this application have at least the following technical effects:

[0016] This application provides a method for predicting and controlling the fluid leakage flow rate of a horizontal well plunger lift. The method sets a time step, initializes the plunger velocity and driving pressure difference to obtain initial plunger velocity and initial driving pressure difference, and executes parameter determination and parameter update steps to determine the fluid leakage flow rate of the horizontal well plunger lift, the top liquid column height at the current time step, the driving pressure difference at the current time step, and the plunger velocity at the current time step, respectively. Convergence is determined using the determined driving pressure difference and plunger velocity at the current time step. Based on the fluid leakage flow rate, the top liquid column height at the current time step, the time step, and the tubing inner diameter, the top liquid column height for the next time step is determined. Based on the plunger velocity and time step, the plunger displacement at the current time step is determined. If the plunger displacement at the current time step is greater than or equal to the bottomhole landing device depth, the parameter determination step is terminated; otherwise, the parameter determination step is iteratively executed until the plunger displacement at the current time step is greater than or equal to the bottomhole landing device depth. The output driving differential pressure and fluid leakage flow rate at the current time step are used as control parameters and transmitted to the well site control system. Based on these parameters, the well site control system adjusts the opening of the wellhead throttle valve in real time. This solves the problem that existing technologies heavily rely on empirical parameters, making it difficult to quantify the dynamic changes in leakage flow rate and driving differential pressure in real time, which leads to low efficiency and poor stability in the horizontal well plunger lifting process design. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments of this application or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 A flowchart illustrating a method for predicting and controlling the leakage flow rate of fluid in a horizontal well plunger lift, provided as an embodiment of this application;

[0019] Figure 2 A graph showing the change in plunger velocity during the plunger lifting process in a horizontal well, provided in an embodiment of this application;

[0020] Figure 3 This application provides a graph showing the displacement change of the plunger during the horizontal well plunger lifting process.

[0021] Figure 4 A graph showing the leakage flow rate variation during the horizontal well plunger lifting process provided in this application embodiment;

[0022] Figure 5 A curve showing the change in driving pressure differential during the lifting process of a horizontal well plunger, provided in an embodiment of this application;

[0023] Figure 6 A schematic diagram of a horizontal well plunger lifting fluid leakage flow prediction and control device provided in this application embodiment;

[0024] Figure 7 This is a schematic diagram of a horizontal well plunger lifting fluid leakage flow prediction and control server provided in an embodiment of this application. Detailed Implementation

[0025] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0026] The following description of some technologies involved in the embodiments of this application is provided to aid understanding and should be considered merely exemplary. Therefore, those skilled in the art should recognize that various changes and modifications can be made to the embodiments described herein without departing from the scope and spirit of this application. Similarly, for clarity and brevity, some descriptions of well-known functions and structures are omitted in the following description.

[0027] This application provides a method for predicting and controlling the leakage flow rate of fluid during horizontal well plunger lifting, such as... Figure 1 As shown, the method includes steps S101 to S110. Wherein, Figure 1 This is merely one execution order shown in the embodiments of this application, and does not represent the only execution order of a method for predicting and controlling the leakage flow of fluid in a horizontal well plunger lifting system. Where the final result can be achieved, Figure 1 The steps shown can be performed in parallel or in reverse order.

[0028] S101: Set the time step, initialize the piston speed and driving pressure difference to obtain the initial piston speed and initial driving pressure difference, and execute the parameter determination step and parameter update step.

[0029] Specifically, the time step is used to divide the time interval in subsequent calculations.

[0030] The parameter determination steps include S102 to S107. The parameter update steps include S108 to S110.

[0031] Specifically, before performing the parameter determination step, it is also necessary to obtain gas well parameters and plunger parameters. Gas well parameters include tubing inner diameter, well depth, well inclination angle, wellbore curvature, wellhead oil pressure, wellhead temperature, wellhead casing pressure, and bottomhole setter depth. Plunger parameters include plunger mass, plunger outer diameter, and plunger length.

[0032] It should be noted that there is a corresponding relationship between well depth and well inclination angle. Specifically, the well inclination angle can be considered as... The value of the well inclination angle is obtained by interpolating the well depth, which is a function of the well depth. Based on the upward displacement of the plunger, the well depth position of the plunger at this time is calculated.

[0033] First, calculate the actual position of the plunger in the wellbore: .in, L represents the position of the plunger in the wellbore, and L represents the depth of the bottom-mounted device. This represents the piston displacement at the current time step.

[0034] Find the well depth range that satisfies the following conditions: .in, This is the depth of the previous well section. This represents the current depth of the well section. The depth of the well section is then used as the well depth.

[0035] exist ~ Within the interval, perform linear interpolation on the well inclination angle: .in, This represents the wellbore inclination angle corresponding to the current plunger position. The inclination angle of the previous well section. This represents the inclination angle of the current well section.

[0036] S102: Determine the fluid leakage flow rate of the horizontal well plunger lift based on the first parameter.

[0037] The fluid leakage flow rate of the horizontal well plunger lift is determined based on the first parameter, including the following.

[0038] The first parameters include: initial plunger velocity, initial driving pressure differential, tubing inner diameter, well inclination angle, wellbore curvature, plunger outer diameter, and plunger length.

[0039] The expression for determining the fluid leakage flow rate during horizontal well plunger lifting is: .in, The fluid leakage flow rate during horizontal well plunger lifting. The inner diameter of the oil pipe. The gap height, For liquid viscosity, For the initial driving pressure difference, For the plunger length, For the density of the liquid, It is the acceleration due to gravity. The well inclination angle, For the eccentricity, This represents the piston speed.

[0040] Specifically, liquid leakage flow rate The unit is cubic meters per second (m 3 / s), used to quantify fluid leakage during plunger lifting. Inner diameter of the tubing. The unit is meters (m), and the gap height is... The unit is meter (m), reflecting the size of the gap between the plunger and the inner wall of the tubing. Liquid viscosity. The unit is Pascal-second (Pa·s). Initial driving pressure difference. The unit is Pascal (Pa). Plunger length The unit is meter (m). Liquid density The unit is kilograms per cubic meter (kg / m³) 3 Gravitational acceleration The speed is usually taken as 9.81 m / s. 2 . Well inclination angle The unit is degrees.

[0041] .in, For the plunger mass, The outer diameter of the plunger. For wellbore curvature, This refers to the piston stiffness. .

[0042] Specifically, eccentricity This describes the eccentricity of the plunger within the tubing; the greater the eccentricity, the greater the leakage flow. Plunger mass. The unit is kilogram (kg). Plunger outer diameter The unit is meters (m). Wellbore curvature The unit is degrees per 30 meters (° / 30m). Wellbore curvature reflects the degree of bending in the wellbore and affects the eccentricity of the plunger. Plunger stiffness. The unit is Newtons per meter (N / m), and plunger stiffness reflects the plunger's ability to resist deformation.

[0043] S103: Based on the second parameter and the liquid leakage flow rate, determine the top liquid column height and the driving pressure difference of the current time step.

[0044] Based on the second parameter and the liquid leakage flow rate, determine the top liquid column height and the driving pressure difference at the current time step, including the following:

[0045] The second parameter includes: leakage flow rate, tubing inner diameter, well inclination angle, wellhead oil pressure, wellhead casing pressure, and bottom hole placement depth.

[0046] The expression for determining the driving pressure difference at the current time step is: .in, The driving pressure difference at the current time step. The driving pressure difference of the previous time step. This refers to the pressure change at the top of the plunger. This represents the pressure change at the bottom of the plunger.

[0047] Specifically, the unit of the parameters in the expression for the driving pressure difference at the current time step is Pascal (Pa).

[0048] .in, For mixed density, The height is calculated for the upward movement of gas. The height is calculated based on the liquid leakage. , The gas leakage flow rate during horizontal well plunger lifting. For plunger lifting time , The fluid leakage flow rate during horizontal well plunger lifting.

[0049] Specifically, mixing density The unit is kilograms per cubic meter (kg / m³) 3 The density is determined by comprehensively considering the mixing of gas and liquid in the liquid column at the top of the plunger. The upward displacement height of the gas is also considered. The unit is meters (m), reflecting the height to which gas rises during the plunger lift process. Plunger lift time. The unit is seconds (s). Gas leakage flow rate during horizontal well plunger lifting. The unit is cubic meters per second (m 3 / s). Liquid leakage equivalent height. The unit is meters (m), which reflects the height of liquid leakage during the plunger lifting process.

[0050] .in, For gas viscosity, This refers to the density of natural gas.

[0051] .

[0052] .in, This refers to the gas content of the liquid column at the top of the plunger. For the density of natural gas, , This represents the height of the top liquid column.

[0053] Specifically, the gas content of the liquid column at the top of the plunger This reflects the proportion of gas in the liquid column at the top of the plunger. Top liquid column height. The unit is meters (m). Natural gas density. The unit is kilograms per cubic meter (kg / m³) 3 ).

[0054] Specifically, the expression for natural gas density is: . .in, For wellhead oil pressure, The wellhead temperature, The molecular weight of natural gas. Let be the ideal gas constant. For natural gas deviation factor, The critical pressure. This is the critical temperature.

[0055] Specifically, natural gas density The unit is kilograms per cubic meter (kg / m³) 3 Wellhead oil pressure The unit is Pascal (Pa). Natural gas molecular weight A possible value is 16.04 kg / mol. Ideal gas constant. It can take the value 8.314 J / (mol·K).

[0056] The expression for determining the height of the top liquid column is: .in, This is the height of the top liquid column. For wellhead casing pressure, For wellhead oil pressure, This refers to the depth of the well bottom positioning device.

[0057] Specifically, wellhead casing pressure and wellhead oil pressure The unit is Pascal (Pa). Bottom landing depth The unit is meters (m), which represents the vertical distance from the wellhead to the bottom of the well.

[0058] S104: Determine the piston speed at the current time step based on Newton's second law.

[0059] The piston velocity at the current time step is determined based on Newton's second law, including the following:

[0060] The dynamic equations for piston lifting are constructed based on Newton's second law, and the acceleration in the dynamic equations are solved.

[0061] The piston velocity at the current time step is determined based on acceleration. The expression for the piston velocity at the current time step is: .in, The piston speed at the current time step. This represents the piston speed in the previous time step. For acceleration, For time step.

[0062] Specifically, the dynamic equation for plunger lifting is: .in, For the plunger mass, For fluid mass, For acceleration, To drive the pressure difference, For fluid resistance, This is friction. . . The drag coefficient, . The Reynolds number is... . For mixed viscosity, . , For gas viscosity, The coefficient of friction, , For roughness.

[0063] S105: Convergence is determined using the driving pressure difference and the piston speed at the current time step.

[0064] S106: If the convergence condition is met, output the driving pressure difference and the piston speed at the current time step.

[0065] The convergence condition is: the ratio of the difference between the driving pressure difference of the current time step and the driving pressure difference of the previous time step to the driving pressure difference of the previous time step is less than 0.1%, and the ratio of the difference between the piston speed of the current time step and the piston speed of the previous time step to the piston speed of the previous time step is less than 0.1%.

[0066] Specifically, the difference here can be the absolute value of the difference.

[0067] S107: If the convergence condition is not met, assign the driving pressure difference of the current time step to the initial driving pressure difference, assign the piston speed of the current time step to the initial piston speed, and iteratively execute the parameter determination step until the convergence condition is met.

[0068] S108: Determine the top liquid column height for the next time step based on the liquid leakage flow rate, the top liquid column height at the current time step, the time step length, and the tubing inner diameter.

[0069] Based on the liquid leakage flow rate, the top liquid column height at the current time step, the time step length, and the tubing inner diameter, determine the top liquid column height at the next time step, including the following:

[0070] The expression for determining the height of the top liquid column at the next time step is: .in, The height of the top liquid column at the next time step. The fluid leakage flow rate during horizontal well plunger lifting. This represents the height of the top liquid column at the current time step. For time step, This refers to the inner diameter of the oil pipe.

[0071] S109: Based on the plunger velocity and time step length of the current time step, determine the plunger displacement of the current time step. If the plunger displacement of the current time step is greater than or equal to the bottom hole landing device depth, terminate the parameter determination step; otherwise, use the plunger velocity and driving pressure difference of the current time step as the initial plunger velocity and initial driving pressure difference of the next time step, and iteratively execute the parameter determination step based on the top liquid column height of the next time step until the plunger displacement of the current time step is greater than or equal to the bottom hole landing device depth.

[0072] Specifically, the position of the plunger at the current time step can be obtained based on the plunger displacement at the current time step.

[0073] Based on the piston speed and time step size at the current time step, determine the piston displacement at the current time step, including the following:

[0074] The expression for determining the piston displacement at the current time step is: .in, This represents the piston displacement at the current time step. This represents the piston displacement in the previous time step. The piston speed at the current time step. For time step.

[0075] The following example illustrates this application further.

[0076] This embodiment takes a gas well in a gas field as an example to illustrate in detail the calculation process and result analysis of the dynamic parameters of the plunger gas lift, as shown in Table 1.

[0077] Table 1 Gas Wellbore Parameters

[0078]

[0079] The wellbore parameters of a gas well in a certain gas field are shown in Table 1. From the wellhead to 500m, the well is in a vertical section. Then, directional drilling begins, with the inclination angle increasing from 0° to 15° at a wellbore curvature of 1.80° / 30m. At 750m, it enters a stable inclination section, maintaining a 15° inclination angle until 1800m. The inclination is then increased to 90°, finally entering a horizontal section at 3400m, where the inclination angle stabilizes at 90°. The wellhead oil pressure is 2MPa, the casing pressure is 3.2MPa, the wellhead temperature is 20℃, the plunger mass is 5kg, the plunger outer diameter is 59mm, the plunger length is 460mm, the tubing inner diameter is 62mm, and the plunger placement depth is 3000m.

[0080] Set the tubing inner diameter D to 62mm, and the wellhead oil pressure... The wellhead casing pressure is 2 MPa. The pressure is 3.2 MPa, and the wellhead temperature is... At 20℃, the plunger mass It weighs 5 kg, and the outer diameter of the plunger is... The plunger length is 59mm. The depth of the well bottom placement device is 460mm. It is 3000m.

[0081] The density of natural gas was calculated. It is 13.22 kg / m³.

[0082] Time step Set to 0.02s, plunger speed Set to 0.1 m / s, initial driving pressure difference The initial setting is 10 kPa.

[0083] The fluid leakage flow rate during horizontal well plunger lift was calculated. 2.78×10 -4 m 3 / s, this parameter reflects the leakage of liquid during the plunger lifting process.

[0084] Calculate the height of the top liquid column The value is 133.41m, and the driving differential pressure at the current time step is updated. The pressure is 9.45 kPa.

[0085] Based on Newton's second law, a dynamic equation for piston lifting is constructed. Combining this with the previously calculated parameters, the piston velocity at the current time step is calculated. The value is 0.13 m / s, which reflects the piston's motion state at the current moment.

[0086] Convergence is determined using the driving pressure difference and piston velocity at the current time step. If the convergence condition is not met, the driving pressure difference at the current time step is... Assigned to the initial driving pressure difference The piston speed at the current time step Assign initial plunger speed The parameter determination steps are executed iteratively until the convergence condition is met.

[0087] After multiple iterations, the driving pressure difference at the current time step is finally obtained. The piston speed at the current time step is 13.74 kPa. The speed is 2.76 m / s. Based on this, the height of the top liquid column in the next time step is calculated using the corresponding formula. It is 131.23m.

[0088] The plunger displacement at the current time step is 0.051m. Since the plunger displacement is less than the depth of the bottom-of-well seat, it means that the plunger has not yet reached the wellhead. The parameter determination step is executed iteratively until the plunger position is reached and the plunger reaches the wellhead position.

[0089] By performing the calculations according to the above calculation process, the evolution of dynamic parameters during the plunger lifting process can be obtained.

[0090] Figure 2 The plunger velocity variation curve during the horizontal well plunger lifting process provided in the embodiments of this application shows that the plunger velocity first increases and then decreases, with a variation range covering 0 m / s to 12 m / s. Figure 3 The plunger displacement change curve during the horizontal well plunger lifting process provided in the embodiments of this application shows that the plunger displacement gradually increases over time. Figure 4 The leakage flow rate change curve during the horizontal well plunger lifting process provided in the embodiments of this application shows that the liquid leakage flow rate first increases and then decreases over time. Figure 5 The curve of driving differential pressure change during the horizontal well plunger lifting process provided in the embodiments of this application shows that the liquid leakage flow rate first increases and then decreases over time.

[0091] Table 2 presents the dynamic parameters of the plunger lifting process in the first 100 seconds. The data shows that as the plunger lifts, its operating speed initially increases and then decreases, and the fluid leakage flow rate also increases with the speed. Simultaneously, in different well sections, the fluid leakage flow rate varies with the well inclination angle, exhibiting a combined effect of driving force, gravity, fluid resistance, and friction. The plunger leakage flow rate first reaches its peak, then continues to lift until it reaches the wellhead.

[0092] Therefore, based on known wellbore and plunger parameters, the real-time changes in key dynamic parameters such as plunger position, plunger velocity, fluid leakage flow rate, and driving pressure differential during the plunger lifting process can be accurately determined on-site. Based on these predictions, production operation parameters for specific well sections can be optimized, providing crucial theoretical guidance for improving the fluid carrying efficiency of the gas-lift plunger and for optimal decision-making.

[0093] Table 2 Dynamic parameter data of plunger lifting in the first 100 seconds

[0094]

[0095] S110: The output current time step driving pressure difference and liquid leakage flow rate are used as control parameters and transmitted to the well site control system. The well site control system adjusts the opening of the wellhead throttle valve in real time based on the control parameters.

[0096] Specifically, the liquid leakage flow rate can be used as a result after each plunger lift to evaluate the efficiency of the plunger lift.

[0097] The following example further illustrates S110.

[0098] Get the driving pressure difference at the current time step The piston speed at the current time step and the piston displacement at the current time step The well site PLC control system (programmable logic control system) receives the above parameters in real time.

[0099] Warning trigger location The distance from the wellhead is set to 80m. When the plunger displacement at the current time step is monitored... When this happens, the system enters an early warning state and initiates high-frequency data sampling. The plunger displacement at the current time step can also be understood as the plunger position at the current time step.

[0100] Driven differential pressure rise rate threshold The setting is 50 kPa / s, used to determine whether the plunger is accelerating the pushing fluid column closer to the wellhead.

[0101] Target smooth unloading pressure drop rate The setting is -20 kPa / s, which represents the desired rate of gradual decrease in wellhead pressure.

[0102] When the system detects the piston displacement at the current time step Within the preset range, and the driving pressure difference at the current time step. When the plunger continues to rise, it is determined that it is about to carry the fluid section to the wellhead. Preventive control measures are required before unloading, including the following:

[0103] Specifically, the preset range is 0m to 80m.

[0104] The control system calculates the average rate of increase of the driving pressure difference over the past 3 seconds. .

[0105] like This immediately triggers the throttle valve control program.

[0106] The system uses a PI control algorithm to dynamically calculate the adjustment amount of the throttle valve opening, based on the actual pressure drop rate. With target smooth unloading pressure drop rate deviation As input, the percentage adjustment of the throttle valve opening is calculated based on the deviation: .in, This refers to the percentage adjustment of the throttle valve opening. This is the proportional gain coefficient. This is the integral gain coefficient. For plunger lifting time Take 0.1–0.3 (%·kPa) -1 ·s -1 ), Take 0.01–0.05 (%·kPa) -1 ·s -2 The control system will calculate... The signal is converted into an electrical signal and sent to the electric actuator of the wellhead throttle valve, instructing it to close the opening degree according to the calculated value.

[0107] To prevent excessive pressure or valve closure due to over-throttling, safety boundaries are set. The minimum safe opening is set at 15%, and under no circumstances should the throttling valve opening fall below this value to ensure sufficient flow to prevent pressure buildup. The maximum permissible casing pressure is set at 90% of the wellhead casing pressure safety limit. If the casing pressure approaches this value during adjustment, the throttling valve closure is paused, and an alarm is triggered.

[0108] By gradually closing the throttle valve in advance, the pressure shock when the plunger reaches the wellhead can be buffered, avoiding liquid slippage and violent gas expansion caused by sudden pressure drop, thereby achieving smooth unloading of the liquid flow, protecting surface pipeline equipment, and improving the liquid recovery rate.

[0109] This application also provides a horizontal well plunger lifting fluid leakage flow prediction and control device 600, such as... Figure 6 As shown, the device includes: an execution module 601, a parameter determination module 602, and a parameter update module 603.

[0110] The execution module 601 is used to set the time step, initialize the piston speed and driving pressure difference to obtain the initial piston speed and initial driving pressure difference, and execute the parameter determination step and parameter update step.

[0111] The parameter determination module 602 is used to determine the fluid leakage flow rate of the horizontal well plunger lift based on the first parameter. Based on the second parameter and the fluid leakage flow rate, it determines the top liquid column height and the driving pressure difference at the current time step. It determines the plunger velocity at the current time step based on Newton's second law. It then uses the determined driving pressure difference and plunger velocity at the current time step for convergence testing. If the convergence condition is met, it outputs the driving pressure difference and plunger velocity at the current time step. If the convergence condition is not met, it assigns the driving pressure difference at the current time step to the initial driving pressure difference and the plunger velocity at the current time step to the initial plunger velocity, and iterates through the parameter determination steps until the convergence condition is met.

[0112] The parameter update module 603 performs parameter update steps based on the fluid leakage flow rate when convergence conditions are met, the top liquid column height at the current time step, and the time step length. This includes: determining the top liquid column height for the next time step based on the fluid leakage flow rate, the top liquid column height at the current time step, the time step length, and the tubing inner diameter; determining the plunger displacement at the current time step based on the plunger velocity and time step length; and terminating the parameter determination step if the plunger displacement at the current time step is greater than or equal to the bottom hole landing device depth. Otherwise, the plunger velocity and driving pressure difference at the current time step are used as the initial plunger velocity and initial driving pressure difference for the next time step, and the parameter determination step is iteratively performed based on the top liquid column height at the next time step until the plunger displacement at the current time step is greater than or equal to the bottom hole landing device depth. The output driving pressure difference and fluid leakage flow rate at the current time step are used as control parameters and transmitted to the well site control system. The well site control system adjusts the wellhead choke valve opening in real time based on these control parameters.

[0113] Some modules in the apparatus described in this application can be described in the general context of computer-executable instructions that are executed by a computer, such as program modules. Generally, program modules include routines, programs, objects, components, data structures, classes, etc., that perform a specific task or implement a specific abstract data type. This application can also be practiced in distributed computing environments where tasks are performed by remote processing devices connected via a communication network. In distributed computing environments, program modules can reside in local and remote computer storage media, including storage devices.

[0114] The apparatus or module described in the above embodiments can be implemented by a computer chip or physical entity, or by a product with a certain function. For ease of description, the above apparatus is described by dividing it into various modules according to their functions. When implementing the embodiments of this application, the functions of each module can be implemented in one or more software and / or hardware. Of course, a module that implements a certain function can also be implemented by combining multiple sub-modules or sub-units.

[0115] The methods, apparatus, or modules described in this application can be implemented in a computer-readable program code manner. The controller can be implemented in any suitable manner, for example, as a microprocessor or processor and a computer-readable medium storing computer-readable program code (e.g., software or firmware) executable by the (micro)processor, logic gates, switches, application-specific integrated circuits (ASICs), programmable logic controllers, and embedded microcontrollers. Examples of controllers include, but are not limited to, the following microcontrollers: ARC 625D, Atmel AT91SAM, Microchip PIC18F26K20, and Silicon Labs C8051F320. A memory controller can also be implemented as part of the control logic of a memory. Those skilled in the art will also recognize that, in addition to implementing the controller in purely computer-readable program code manner, the same functionality can be achieved by logically programming the method steps to make the controller take the form of logic gates, switches, application-specific integrated circuits, programmable logic controllers, and embedded microcontrollers. Therefore, such a controller can be considered a hardware component, and the means included within it for implementing various functions can also be considered as structures within the hardware component. Alternatively, the device used to implement various functions can be viewed as either a software module that implements the method or a structure within a hardware component.

[0116] like Figure 7 As shown in the figure, this application embodiment also provides a horizontal well plunger lift fluid leakage flow prediction and control server, including a memory 701 and a processor 702; the memory 701 is used to store computer-executable instructions; the processor 702 is used to execute computer-executable instructions to implement the horizontal well plunger lift fluid leakage flow prediction and control method described above in this application embodiment.

[0117] This application also provides a computer-readable storage medium storing executable instructions. When a computer executes the executable instructions, it can implement the method for predicting and controlling the leakage flow of liquid in a horizontal well plunger lifting system as described above in this application.

[0118] As can be seen from the above description of the embodiments, those skilled in the art can clearly understand that this application can be implemented by means of software plus necessary hardware. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, can be embodied in the form of a software product, or it can be embodied in the process of data migration. The computer software product can be stored in a storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, mobile terminal, server, or network device, etc.) to execute the methods described in the embodiments of this application.

[0119] The various embodiments described in this specification are presented in a progressive manner. Similar or identical parts between embodiments can be referred to interchangeably. Each embodiment focuses on its differences from other embodiments. All or part of this application can be used in numerous general-purpose or special-purpose computer system environments or configurations.

[0120] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit this application. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of this application.

Claims

1. A method for predicting and controlling the leakage flow rate of fluid in a horizontal well plunger lift, characterized in that, include: Set the time step, initialize the piston speed and driving pressure difference to obtain the initial piston speed and initial driving pressure difference, and execute the parameter determination step and parameter update step; The parameter determination steps include: The fluid leakage flow rate during horizontal well plunger lifting is determined based on the first parameter; Based on the second parameter and the liquid leakage flow rate, determine the top liquid column height and the driving pressure difference at the current time step; The piston speed at the current time step is determined based on Newton's second law; Convergence is determined by using the driving pressure difference and the piston speed at the current time step. If the convergence condition is met, output the driving pressure difference and the piston speed at the current time step. If the convergence condition is not met, assign the driving pressure difference of the current time step to the initial driving pressure difference, assign the piston speed of the current time step to the initial piston speed, and iteratively execute the parameter determination steps until the convergence condition is met. The parameter update step is performed based on the liquid leakage flow rate when the convergence condition is met, the top liquid column height at the current time step, and the time step size, including: The top liquid column height for the next time step is determined based on the liquid leakage flow rate, the top liquid column height at the current time step, the time step length, and the tubing inner diameter. Based on the plunger velocity and time step length of the current time step, determine the plunger displacement of the current time step. If the plunger displacement of the current time step is greater than or equal to the bottom hole landing device depth, terminate the parameter determination step; otherwise, use the plunger velocity and driving pressure difference of the current time step as the initial plunger velocity and initial driving pressure difference of the next time step, and iteratively execute the parameter determination step based on the top liquid column height of the next time step until the plunger displacement of the current time step is greater than or equal to the bottom hole landing device depth. The driving differential pressure and liquid leakage flow rate of the current time step are output as control parameters and transmitted to the well site control system. The well site control system adjusts the opening of the wellhead throttle valve in real time based on the control parameters. The first parameter includes: initial plunger velocity, initial driving pressure differential, tubing inner diameter, well inclination angle, wellbore curvature, plunger outer diameter, and plunger length; The second parameter includes: gas leakage flow rate, tubing inner diameter, well inclination angle, wellhead oil pressure, wellhead casing pressure, and bottom hole placement device depth; The convergence condition is as follows: the absolute value of the ratio of the difference between the driving pressure difference of the current time step and the driving pressure difference of the previous time step to the driving pressure difference of the previous time step is less than 0.1%, and the absolute value of the ratio of the difference between the piston speed of the current time step and the piston speed of the previous time step to the piston speed of the previous time step is less than 0.1%.

2. The method for predicting and controlling the leakage flow rate of fluid in horizontal well plunger lifting according to claim 1, characterized in that, The determination of the fluid leakage flow rate during horizontal well plunger lift based on the first parameter includes: ;in, The fluid leakage flow rate during horizontal well plunger lifting. The inner diameter of the oil pipe. The gap height, For liquid viscosity, To drive the pressure difference, For the plunger length, For the density of the liquid, It is the acceleration due to gravity. The well inclination angle, For the eccentricity, The piston speed; ;in, For the plunger mass, The outer diameter of the plunger. For wellbore curvature, For plunger stiffness; 。 3. The method for predicting and controlling the leakage flow rate of fluid in horizontal well plunger lifting according to claim 2, characterized in that, The expression for determining the driving pressure difference at the current time step is: ;in, The driving pressure difference at the current time step. The driving pressure difference of the previous time step. This refers to the pressure change at the top of the plunger. This refers to the pressure change at the bottom of the plunger; ;in, For mixed density, The height is calculated for the upward movement of gas. The height is calculated based on the liquid leakage. , The gas leakage flow rate during horizontal well plunger lifting. For plunger lifting time , The fluid leakage flow rate during horizontal well plunger lifting; ;in, For gas viscosity, Density of natural gas; ； ;in, This refers to the gas content of the liquid column at the top of the plunger. For the density of natural gas, , This refers to the height of the top liquid column; The expression for determining the height of the top liquid column is: ;in, This is the height of the top liquid column. For wellhead casing pressure, For wellhead oil pressure, This refers to the depth of the well bottom positioning device.

4. The method for predicting and controlling the leakage flow rate of fluid in horizontal well plunger lifting according to claim 3, characterized in that, The method for determining the piston velocity at the current time step based on Newton's second law includes: The dynamic equations for piston lifting are constructed based on Newton's second law, and the acceleration in the dynamic equations are solved. The dynamic equation for plunger lifting is: ;in, For the plunger mass, For fluid mass, For acceleration, To drive the pressure difference, For fluid resistance, For friction, , , The drag coefficient, , The Reynolds number is... , For mixed viscosity, , , For gas viscosity, The coefficient of friction, , For roughness; The piston velocity at the current time step is determined based on acceleration. The expression for the piston velocity at the current time step is: ;in, The piston speed at the current time step. The piston speed in the previous time step. For acceleration, For time step.

5. The method for predicting and controlling the leakage flow rate of fluid in horizontal well plunger lifting according to claim 4, characterized in that, The determination of the top liquid column height for the next time step based on the liquid leakage flow rate, the current top liquid column height, the time step length, and the tubing inner diameter includes: ;in, The height of the top liquid column at the next time step. The fluid leakage flow rate during horizontal well plunger lifting. This represents the height of the top liquid column at the current time step. For time step, This refers to the inner diameter of the oil pipe.

6. The method for predicting and controlling the leakage flow rate of fluid in horizontal well plunger lifting according to claim 5, characterized in that, The determination of the piston displacement at the current time step based on the piston speed and time step size at the current time step includes: ;in, This represents the piston displacement at the current time step. This represents the piston displacement in the previous time step. The piston speed at the current time step. For time step.

7. A device for predicting and controlling the leakage flow rate of fluid in a horizontal well plunger lifting operation, characterized in that, The device performs the method as described in any one of claims 1 to 6, including: The execution module is used to set the time step, initialize the piston speed and driving pressure difference to obtain the initial piston speed and initial driving pressure difference, and execute the parameter determination step and parameter update step. The parameter determination module is used to determine the fluid leakage flow rate of the horizontal well plunger lift based on the first parameter; determine the top liquid column height and the driving pressure difference of the current time step based on the second parameter and the fluid leakage flow rate; determine the plunger velocity of the current time step based on Newton's second law; perform convergence judgment using the determined driving pressure difference and plunger velocity of the current time step; if the convergence condition is met, output the driving pressure difference and plunger velocity of the current time step; if the convergence condition is not met, assign the driving pressure difference of the current time step to the initial driving pressure difference, assign the plunger velocity of the current time step to the initial plunger velocity, and iteratively execute the parameter determination steps until the convergence condition is met. The parameter update module is used to perform the parameter update step based on the liquid leakage flow rate when the convergence condition is met, the top liquid column height at the current time step, and the time step length. This includes: determining the top liquid column height for the next time step based on the liquid leakage flow rate, the top liquid column height at the current time step, the time step length, and the tubing inner diameter; determining the plunger displacement at the current time step based on the plunger velocity and the time step length; if the plunger displacement at the current time step is greater than or equal to the bottom hole landing device depth, terminating the parameter determination step; otherwise, using the plunger velocity and driving pressure difference at the current time step as the initial plunger velocity and initial driving pressure difference for the next time step, and iteratively performing the parameter determination step based on the top liquid column height at the next time step until the plunger displacement at the current time step is greater than or equal to the bottom hole landing device depth; and transmitting the output driving pressure difference and liquid leakage flow rate at the current time step as control parameters to the well site control system, which adjusts the wellhead choke valve opening in real time based on the control parameters.

8. A server for predicting and controlling the leakage flow rate of fluid in a horizontal well plunger lifting system, characterized in that, Including memory and processor; The memory is used to store computer-executable instructions; The processor is configured to execute the computer-executable instructions to implement the method according to any one of claims 1-6.

9. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores executable instructions, which, when executed by a computer, enable the implementation of the method as described in any one of claims 1-6.

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