A simulation experimental method for well depressurization and detection

Abstract

The present application discloses a simulation experimental method for wellbore pressure reduction and detection. The conditions of different power component speeds and variable frequency asynchronous motor speeds are simulated to observe and record the pressure reduction effect of the screw pump on the annulus under different conditions, and the pressure changes of the first sensor, the second sensor and the third sensor are recorded at the same time; the power component, the variable frequency asynchronous motor, the first stop valve and the second stop valve are closed, and new mud containing solid phase particles is added to the mud circulation box to simulate the annulus pressure reduction effect of the screw pump under different viscosities and densities. Therefore, the present application realizes a comprehensive evaluation and optimization of the performance of the screw pump by constructing a unique medium flow channel and integrating multiple sensors and data acquisition instruments. This method not only improves the experimental efficiency and accuracy, but also provides a scientific basis for equipment selection and parameter setting in actual drilling operations.

Description

Technical Field

[0001] The present application relates to the field of offshore petroleum engineering technology, and in particular to a simulation experimental method for well depressurization and detection. Background Art

[0002] As drilling depth continues to increase, most offshore oil fields often face the problem of narrow density window drilling fluid leakage in the middle and late stages of development. This problem has seriously restricted safe and efficient drilling downhole. Therefore, in the environment of ultra-high temperature, high pressure and narrow density window, the high density of drilling fluid, large circulation friction and narrow circulation operation window make the control and monitoring of downhole pressure the current top priority.

[0003] At present, many researchers have conducted in-depth research on downhole pressure reduction tools and used simulation software to simulate the effect of screw pumps on reducing downhole pressure under mud fluid conditions. However, the existing technology is mainly limited to the computer simulation stage and lacks actual devices that can truly simulate the downhole pressure environment. More importantly, due to the lack of means to monitor downhole annular pressure and other parameters in real time through sensors, it is impossible to achieve dynamic control of downhole pressure. Summary of the invention

[0004] The embodiments of the present application solve the technical problems in the prior art of lacking a practical device to simulate the actual downhole pressure and being unable to achieve dynamic control of the downhole pressure by providing a simulation experimental method for downhole pressure reduction and detection.

[0005] The present application embodiment provides a simulation experimental method for well depressurization and detection, which is applied to a simulation device, and the method includes:

[0006] S1: inject mud into the mud circulation box, start the power part to drive the centrifugal pump to operate, the input end of the centrifugal pump extracts mud medium from the mud circulation box, and conveys the mud to the screw pump after pressurization, and at the same time controls the output speed of the variable frequency asynchronous motor, drives the light rod to rotate through the power steering mechanism, and at this time, properly open the first stop valve and the second stop valve, so that the mud can flow through the pipe and sleeve at the output end of the centrifugal pump and the pipe at the return end of the mud circulation box, so as to achieve the purpose of wetting and cleaning the simulation device;

[0007] S2: The pressure changes of the first sensor, the second sensor and the third sensor are collected by a data acquisition instrument until the mud fully fills the inside of the sleeve and a small amount of mud returns to the mud circulation box; wherein the first sensor is installed at the output end of the centrifugal pump, and is used to measure the medium pressure at the inlet; the second sensor passes through the outer wall of the sleeve, extends into the gap, and is close to the return end of the mud circulation box, and is used to measure the medium pressure at the outlet; the third sensor passes through the outer wall of the sleeve, extends into the gap, and is close to the bottom of the screw pump, and is used to measure the sleeve annulus pressure, and the data acquisition instrument is electrically connected to the first sensor, the second sensor and the third sensor;

[0008] S3: fully open the first stop valve and the second stop valve, and detect the pressure changes of the first sensor, the second sensor and the third sensor again, and adjust the speed of the variable frequency asynchronous motor at the same time until the pressures displayed by the first sensor, the second sensor and the third sensor are all stable, then record the pressure changes of the first sensor, the second sensor and the third sensor to evaluate the pressure reduction effect of the screw pump on the annulus;

[0009] S4: Simulate different power unit speeds and variable frequency asynchronous motor speeds to observe and record the depressurization effect of the screw pump on the annulus under different conditions, and record the pressure changes of the first sensor, the second sensor and the third sensor;

[0010] S5: Close the power parts, the variable frequency asynchronous motor, the first stop valve and the second stop valve, add new mud liquid containing solid particles into the mud circulation box, simulate the annular space pressure reduction effect of the screw pump under different viscosities and densities, and repeat steps S1-S4.

[0011] In a possible implementation, the simulation device includes a mounting platform, a power component, a centrifugal pump, a variable frequency asynchronous motor, a mud circulation box, a power steering mechanism, a bare rod, a screw pump, a sleeve, a data acquisition instrument, a first sensor, a second sensor and a third sensor; the power component, the centrifugal pump, the variable frequency asynchronous motor and the mud circulation box are all installed on the top of the mounting platform; the output end of the power component is connected to the centrifugal pump, and the input end of the centrifugal pump is connected to the output end of the mud circulation box; the output end of the variable frequency asynchronous motor is connected to the power steering mechanism, and the power steering mechanism is connected to the bare rod, and the end of the bare rod away from the power steering mechanism passes through the mounting platform and is connected to the screw pump, the axial direction of the bare rod is perpendicular to the axial direction of the variable frequency asynchronous motor, and the power steering mechanism is used to convert the rotational motion output by the variable frequency asynchronous motor into the rotational motion of the bare rod along the vertical direction;

[0012] The sleeve is installed at the bottom of the mounting platform, and the screw pump is arranged in the sleeve. The inner wall of the sleeve and the outer wall of the screw pump form a gap, and the sleeve and the screw pump are concentric axes; the outer wall of the sleeve is provided with an inlet and an outlet, and the height of the inlet is greater than the height of the outlet; the pipeline at the output end of the centrifugal pump is connected with the inlet, and the inlet is connected with the input flow channel of the screw pump; the pipeline at the return end of the mud circulation box is connected with the outlet; the pipeline at the return end of the mud circulation box and the pipeline at the output end of the centrifugal pump are respectively provided with a first stop valve and a second stop valve.

[0013] In one possible implementation, in S2, the data acquisition instrument is electrically connected to a computer data recording device, and the computer data recording device is configured to record the pressure data collected by the data acquisition instrument and convert the pressure data into a form representing the equivalent circulating density of the screw pump annulus. This conversion process will continue until a small amount of mud is observed to return to the mud circulation box.

[0014] In a possible implementation, in S3, the first stop valve and the second stop valve are slowly opened until they are fully opened; the thresholds of the first stop valve and the second stop valve are both 0.18 MPa, and the speed of the variable frequency asynchronous motor is 2500 rpm.

[0015] In a possible implementation, the pipe at the output end of the centrifugal pump passes through the mounting platform and is connected to the inlet; the pipe at the return end of the mud circulation box passes through the mounting platform and is connected to the outlet.

[0016] In a possible implementation, the power component is a three-phase asynchronous motor.

[0017] In a possible implementation, the power steering mechanism includes a turbine and a worm; the output end of the variable frequency asynchronous motor is connected to the worm; the worm is meshed with the turbine, and the smooth rod is connected to the turbine through a square clip.

[0018] In a possible implementation, an anchor is sleeved on the middle part of the outer wall of the screw pump; and a labyrinth sealing sleeve or a mechanical sealing sleeve is sleeved on the side of the anchor away from the screw pump.

[0019] In a possible implementation, one end of the polished rod away from the power steering mechanism is connected to the double universal joint rod, and one end of the double universal joint rod away from the polished rod is connected to the rotor of the screw pump.

[0020] In a possible implementation, after S5, it also includes: closing the power component, the variable frequency asynchronous motor, the first stop valve and the second stop valve, using a mechanical sealing sleeve or a labyrinth sealing sleeve to simulate the annular space pressure reduction effect of the screw pump under different sealing conditions, and repeating steps S1-S5.

[0021] One or more technical solutions provided in the embodiments of the present application have at least the following technical effects:

[0022] The embodiment of the present application provides a simulation experimental method for pressure reduction and detection in a well. The embodiment of the present application provides a simulation experimental method for pressure reduction and detection in a well. The method simulates the circulation and pressure reduction process of the medium in the well by constructing a unique medium flow channel. Specifically, the output end pipeline of the centrifugal pump, the input flow channel from the inlet of the sleeve to the screw pump, and the flow channel from the top of the screw pump to the outlet together constitute the upper half of the medium circulation flow channel in the well; while the input flow channel and the output flow channel of the screw pump constitute the lower half of the medium pressure reduction flow channel in the well. This design not only restores the real downhole environment, but also enables researchers to accurately evaluate the performance of the screw pump in the simulation experiment, especially its pressure reduction effect on the annulus. In the experiment, the first sensor, the second sensor and the third sensor were installed to monitor the pressure changes of the mud at different positions in real time. These sensors provide key data for analyzing the working state of the screw pump, optimizing the design and improving the pressure reduction effect. In addition, the controllability of the experiment enables researchers to adjust the speed of the power parts, the variable frequency asynchronous motor, and the viscosity and density of the mud, so as to observe and record the pressure reduction effect of the screw pump under different conditions. The power steering mechanism of the present application converts the lateral output power of the variable frequency asynchronous motor into rotational power in the vertical direction, effectively reducing the influence of gravity on the clearance between the rotor and stator of the screw pump, and further improving the accuracy and reliability of the experiment. By pre-wetting and cleaning the simulation device, and adopting automated data acquisition and analysis methods, this method significantly improves the experimental efficiency and reduces time and labor costs. At the same time, this method is not only suitable for the performance evaluation of screw pumps, but also can be used for the research and development of other downhole equipment or processes, providing valuable reference and guidance for actual production. Therefore, the simulation experimental method for downhole pressure reduction and detection provided in the embodiment of the present application realizes a comprehensive evaluation and optimization of the performance of the screw pump by constructing a unique medium flow channel, integrating multiple sensors and data acquisition instruments. This method not only improves the experimental efficiency and accuracy, but also provides a scientific basis for equipment selection and parameter setting in actual drilling operations. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following is a brief introduction to the drawings required for use in the description of the embodiments of the present application. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0024] Figure 1 A schematic diagram of the structure of a simulation device provided in an embodiment of the present application;

[0025] Figure 2 A cross-sectional view of a simulation device provided in an embodiment of the present application;

[0026] Figure 3 A schematic diagram of a flow channel of a simulation device provided in an embodiment of the present application;

[0027] Figure 4 A schematic diagram of the structure of a labyrinth sealing sleeve provided in an embodiment of the present application;

[0028] Figure 5 An exploded view of a labyrinth seal sleeve provided in an embodiment of the present application;

[0029] Figure 6 A schematic diagram of the structure of a mechanical sealing sleeve provided in an embodiment of the present application;

[0030] Figure 7 An exploded view of the mechanical sealing sleeve provided in an embodiment of the present application.

[0031] Icons: 1-installation platform; 2-power parts; 3-centrifugal pump; 4-variable frequency asynchronous motor; 5-mud circulation box; 6-power steering mechanism; 7-bare rod; 8-screw pump; 9-sleeve; 91-inlet; 92-outlet; 10-data acquisition instrument; 11-first sensor; 12-second sensor; 13-third sensor; 14-first stop valve; 15-second stop valve; 16-computer data recording device; 17-anchor; 18-labyrinth sealing sleeve; 19-double universal joint rod; 20-square clip; 21-mechanical sealing sleeve. DETAILED DESCRIPTION

[0032] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0033] In the description of the embodiments of the present application, it should be noted that the orientation or positional relationship indicated by the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the embodiments of the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. The terms "first", "second", and "third" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance. In addition, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be a connection between the two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0034] The present application embodiment provides a simulation experimental method for well depressurization and detection, such as Figures 1 to 7 As shown. The simulation experimental method for downhole pressure reduction and detection uses a simulation device to simulate the downhole working environment. The simulation device includes an installation platform 1, a power piece 2, a centrifugal pump 3, a variable frequency asynchronous motor 4, a mud circulation box 5, a power steering mechanism 6, a polished rod 7, a screw pump 8, a sleeve 9, a data acquisition instrument 10, a first sensor 11, a second sensor 12 and a third sensor 13. The power piece 2, the centrifugal pump 3, the variable frequency asynchronous motor 4 and the mud circulation box 5 are all installed on the top of the installation platform 1. The output end of the power piece 2 is connected to the centrifugal pump 3, and the input end of the centrifugal pump 3 is connected to the output end of the mud circulation box 5. The output end of the variable frequency asynchronous motor 4 is connected to the power steering mechanism 6, and the power steering mechanism 6 is connected to the polished rod 7. The end of the polished rod 7 away from the power steering mechanism 6 passes through the installation platform 1 and is connected to the screw pump 8. The axial direction of the polished rod 7 is perpendicular to the axial direction of the variable frequency asynchronous motor 4. The power steering mechanism 6 is used to convert the rotational motion output by the variable frequency asynchronous motor 4 into the rotational motion of the polished rod 7 along the vertical direction. The sleeve 9 is installed at the bottom of the installation platform 1, and the screw pump 8 is arranged in the sleeve 9. The inner wall of the sleeve 9 and the outer wall of the screw pump 8 form a gap, and the sleeve 9 and the screw pump 8 are concentric axes. The outer wall of the sleeve 9 is provided with an inlet 91 and an outlet 92, and the height of the inlet 91 is greater than the height of the outlet 92. The pipeline at the output end of the centrifugal pump 3 is connected to the inlet 91, and the inlet 91 is connected to the input flow channel of the screw pump 8. The pipeline at the return end of the mud circulation box 5 is connected to the outlet 92. The pipeline at the return end of the mud circulation box 5 and the pipeline at the output end of the centrifugal pump 3 are respectively provided with a first stop valve 14 and a second stop valve 15.

[0035] The simulation experiment method includes:

[0036] S1: Inject the mud into the mud circulation box 5, start the power part 2 to drive the centrifugal pump 3 to operate, the input end of the centrifugal pump 3 extracts the mud medium from the mud circulation box 5, and conveys the mud to the screw pump 8 after pressurization. At the same time, control the output speed of the variable frequency asynchronous motor 4, and drive the light rod 7 to rotate through the power steering mechanism 6. At this time, open the first stop valve 14 and the second stop valve 15 appropriately, so that the mud can flow through the pipe at the output end of the centrifugal pump 3, the sleeve 9 and the pipe at the return end of the mud circulation box 5, so as to achieve the purpose of wetting and cleaning the simulation device.

[0037] It should be noted that the input end of the centrifugal pump 3 extracts mud medium from the mud circulation box 5 and conveys it to the screw pump 8 by pressurization. This process ensures the effective circulation of mud in the simulation device, and the pressurized mud can better simulate the mud circulation state in the actual drilling operation. The first stop valve 14 and the second stop valve 15 are properly opened to allow the mud to flow through the pipe at the output end of the centrifugal pump 3, the sleeve 9 and the pipe at the return end of the mud circulation box 5. This design not only realizes the recycling of mud, but also wets and cleans the simulation device through the flow of mud, which helps to extend the service life of the simulation device and maintain its stable performance.

[0038] S2: The pressure changes of the first sensor 11, the second sensor 12 and the third sensor 13 are collected by the data acquisition instrument 10 until the mud fully fills the inside of the sleeve 9 and a small amount of mud returns to the mud circulation box 5. Among them, the first sensor 11 is installed at the output end of the centrifugal pump 3, and is used to measure the medium pressure at the inlet 91. The second sensor 12 passes through the outer wall of the sleeve 9, extends into the gap, and is close to the return end of the mud circulation box 5, and is used to measure the medium pressure at the outlet 92. The third sensor 13 passes through the outer wall of the sleeve 9, extends into the gap, and is close to the bottom of the screw pump 8, and is used to measure the annular pressure of the sleeve 9. The data acquisition instrument 10 is electrically connected to the first sensor 11, the second sensor 12 and the third sensor 13.

[0039] S3: Fully open the first stop valve 14 and the second stop valve 15, and detect the pressure changes of the first sensor 11, the second sensor 12 and the third sensor 13 again, and adjust the speed of the variable frequency asynchronous motor 4 at the same time until the pressures displayed by the first sensor 11, the second sensor 12 and the third sensor 13 are stable, then record the pressure changes of the first sensor 11, the second sensor 12 and the third sensor 13 to evaluate the pressure reduction effect of the screw pump 8 on the annulus.

[0040] It should be noted that recording the pressure change data of the first sensor 11, the second sensor 12 and the third sensor 13 can intuitively reflect the effect of the screw pump 8 on the annular space pressure reduction. By comparing the pressure data at different speeds or under different operating conditions, the pressure reduction performance of the screw pump 8 can be evaluated and its operating parameters can be further optimized.

[0041] S4: Simulate different speeds of the power part 2 and the variable frequency asynchronous motor 4 to observe and record the pressure reduction effect of the screw pump 8 on the annulus under different conditions, and record the pressure changes of the first sensor 11, the second sensor 12 and the third sensor 13.

[0042] It should be noted that by simulating multiple speed conditions, the pressure reduction performance of the screw pump 8 under different working conditions can be comprehensively evaluated, so as to gain a deeper understanding of the working characteristics of the screw pump 8 under different pressures, flow rates and speeds. This provides a scientific basis for equipment selection and parameter setting in actual drilling operations. During the simulation process, if the pressure change of a certain sensor is abnormal, this may mean that there are potential problems or failures in the system. By promptly discovering and handling these problems, we can effectively avoid safety accidents or equipment damage in actual drilling operations.

[0043] S5: Close the power part 2, the variable frequency asynchronous motor 4, the first stop valve 14 and the second stop valve 15, add new mud liquid containing solid particles into the mud circulation box 5, simulate the annular space pressure reduction effect of the screw pump 8 under different viscosities and densities, and repeat steps S1-S4.

[0044] Specifically, by simulating muds of different viscosities and densities, the annular pressure reduction performance of the screw pump 8 under different working conditions can be comprehensively evaluated, which helps to understand the adaptability of the screw pump 8 under different medium conditions and provide a scientific basis for mud selection in actual drilling operations.

[0045] It should be noted that the embodiment of the present application provides a simulation experimental method for pressure reduction and detection in the well. The method simulates the circulation and pressure reduction process of the medium in the well by constructing a unique medium flow channel. Specifically, the output end pipeline of the centrifugal pump 3, the input flow channel from the inlet 91 of the sleeve 9 to the screw pump 8, and the flow channel from the top of the screw pump 8 to the outlet 92 together constitute the upper half of the medium circulation flow channel in the well; while the input flow channel and the output flow channel of the screw pump 8 constitute the lower half of the medium pressure reduction flow channel in the well. This design not only restores the real well environment, but also enables researchers to accurately evaluate the performance of the screw pump 8 in the simulation experiment, especially its pressure reduction effect on the annulus. In the experiment, the first sensor 11, the second sensor 12 and the third sensor 13 were installed to monitor the pressure changes of the mud at different positions in real time. These sensors provide key data for analyzing the working state of the screw pump 8, optimizing the design and improving the pressure reduction effect. In addition, the controllability of the experiment enables researchers to adjust the speed of the power part 2, the variable frequency asynchronous motor 4, and the viscosity and density of the mud, so as to observe and record the pressure reduction effect of the screw pump 8 under different conditions. The power steering mechanism 6 of the present application converts the lateral output power of the variable frequency asynchronous motor 4 into the rotational power in the vertical direction, effectively reducing the influence of gravity on the clearance between the rotor and the stator of the screw pump 8, and further improving the accuracy and reliability of the experiment. By pre-wetting and cleaning the simulation device and adopting automated data acquisition and analysis methods, the method significantly improves the experimental efficiency and reduces time and labor costs. At the same time, the method is not only applicable to the performance evaluation of the screw pump 8, but also can be used for the research and development of other downhole equipment or processes, providing valuable reference and guidance for actual production. The simulation experimental method for downhole pressure reduction and detection provided in the embodiment of the present application realizes a comprehensive evaluation and optimization of the performance of the screw pump 8 by constructing a unique medium flow channel, integrating multiple sensors and a data acquisition instrument 10. This method not only improves the experimental efficiency and accuracy, but also provides a scientific basis for equipment selection and parameter setting in actual drilling operations.

[0046] In the embodiment of the present application, in S1, the speed of the power part 2 is 2800 rpm, and the speed of the variable frequency asynchronous motor 4 is 1500 rpm. The thresholds of the first stop valve 14 and the second stop valve 15 are both 0.1 MPa. The wetting time of the simulation device is 5 min.

[0047] It should be noted that the wetting time of 5 min ensures that the interior of the simulation device is fully wetted, avoiding experimental errors caused by drying or uneven wetting, and improving the accuracy and reliability of the experiment.

[0048] In an embodiment of the present application, in S2, the data acquisition instrument 10 is electrically connected to a computer data recording device 16, and the computer data recording device 16 is configured to record the pressure data collected by the data acquisition instrument 10, and convert the pressure data into a form representing the equivalent circulating density of the annulus of the screw pump 8. This conversion process will continue until a small amount of mud is observed to return to the mud circulation box 5.

[0049] It should be noted that the pressure data conversion formula is:

[0050] ;

[0051] in, is the equivalent circulation density; is the downhole static density, i.e. the density of the drilling fluid; is the friction pressure drop generated during the flow of mud; h is the wellbore depth, that is, the height of the casing 9.

[0052] In deepwater drilling operations, equivalent circulating density (ECD) is a crucial parameter that is directly related to the stability of the wellbore and the smoothness of mud circulation. If the ECD is too high, it may lead to serious problems such as wellbore rupture and mud loss, which have caused shutdowns and high costs for many drilling projects. In addition, high ECD may also cause the drill to get stuck in the well, seriously hindering the progress of drilling operations, further increasing operating costs, and adversely affecting the overall stability of the wellbore.

[0053] In order to solve the above problems, the present application realizes real-time monitoring of the annular pressure data of the screw pump 8 through the close cooperation of the data acquisition instrument 10 and the computer data recording device 16. The system can provide real-time feedback on the changes in the equivalent circulating density, so that researchers can promptly detect abnormal conditions in the mud circulation, such as abnormal pressure increases or decreases. By accurately controlling ECD, it can be ensured that the circulation state of the drilling fluid in the wellbore meets the design requirements, thereby reducing the probability of accidents, reducing downtime and costs, and improving the economic benefits of the overall drilling operation.

[0054] In the embodiment of the present application, in S3, the first stop valve 14 and the second stop valve 15 are slowly opened until they are fully opened. The thresholds of the first stop valve 14 and the second stop valve 15 are both 0.18 MPa, and the speed of the variable frequency asynchronous motor 4 is 2500 rpm.

[0055] In the embodiment of the present application, the pipe at the output end of the centrifugal pump 3 passes through the mounting platform 1 and is connected to the inlet 91. The pipe at the return end of the mud circulation box 5 passes through the mounting platform 1 and is connected to the outlet 92, thereby improving the integration and compactness of the simulation device.

[0056] In the embodiment of the present application, the power part 2 is a three-phase asynchronous motor. The three-phase asynchronous motor has a high energy conversion efficiency.

[0057] In the embodiment of the present application, the power steering mechanism 6 includes a turbine and a worm. The output end of the variable frequency asynchronous motor 4 is connected to the worm. The worm is meshed with the turbine to achieve effective power transmission. The light rod 7 is connected to the turbine through a square clip 20, thereby ensuring the continuity and stability of power.

[0058] It should be noted that the high-speed rotation of the variable-frequency asynchronous motor 4 can be effectively converted into a low-speed, high-torque output of the turbine, which is crucial for the screw pump 8 because it requires sufficient torque to overcome various resistances underground and ensure the smooth transportation of the mud. In addition, the worm gear has a self-locking characteristic, that is, when the worm stops rotating, the turbine cannot reverse by itself. This characteristic is particularly important when the screw pump 8 is shut down because it can prevent the mud from reversing the screw pump 8 due to backflow. Therefore, the present application ensures the stability and reliability of the screw pump 8 in underground operation through the high reduction ratio and self-locking characteristics of the worm gear. At the same time, the worm gear enables the screw pump 8 to output a larger torque, thereby improving its adaptability under complex well conditions and ensuring the continuous and efficient transportation of mud.

[0059] In the embodiment of the present application, an anchor 17 is sleeved in the middle of the outer wall of the screw pump 8. A labyrinth seal sleeve 18 or a mechanical seal sleeve 21 is sleeved on the side of the anchor 17 away from the screw pump 8.

[0060] In the embodiment of the present application, one end of the polished rod 7 away from the power steering mechanism 6 is connected to the double universal joint rod 19 , and one end of the double universal joint rod 19 away from the polished rod 7 is connected to the rotor of the screw pump 8 .

[0061] Specifically, the double universal joint rod 19 has good buffering and shock absorbing performance, so it can effectively reduce the vibration and noise generated by the screw pump 8 during operation.

[0062] In the embodiment of the present application, after S5, the following steps are further included:

[0063] S6: Close the power part 2, the variable frequency asynchronous motor 4, the first stop valve 14 and the second stop valve 15, use the mechanical sealing sleeve 21 or the labyrinth sealing sleeve 18, simulate the annular space pressure reduction effect of the screw pump 8 under different sealing conditions, and repeat steps S1-S5.

[0064] It should be noted that the present application uses a mechanical seal sleeve 21 to simulate a fully sealed condition. The mechanical seal sleeve 21 is a high-precision sealing device that uses a small gap between two relatively moving sealing surfaces (usually a combination of metal and elastic materials) to prevent fluid leakage. This sealing method can provide extremely high sealing performance and ensure that the annular area of ​​the screw pump 8 is completely isolated from the external environment.

[0065] The present application uses a labyrinth seal sleeve 18 to simulate a semi-sealed condition. The design of the labyrinth seal sleeve 18 is based on the principles of fluid dynamics. It slows down and restricts the flow of fluid through a series of complex channels and obstacles. These channels usually have different cross-sectional shapes and sizes to form multiple throttling and diffusion effects, thereby increasing the resistance to fluid flow. Although the labyrinth seal sleeve 18 cannot completely prevent fluid leakage, it can significantly reduce the amount of leakage. This semi-sealed state allows a certain amount of fluid to pass through, but it is not enough to have a serious impact on the annular space pressure reduction effect.

[0066] The outer wall of the anchor 17 is not equipped with any additional sealing device, so it cannot effectively prevent the fluid from leaking from the annular area to the external environment, which is equivalent to simulating the extreme situation of seal failure. Due to seal failure, a large amount of fluid will leak from the annular area to the external environment, resulting in a significant reduction in the annular pressure reduction effect. Therefore, the embodiment of the present application simulates different sealing conditions by changing the sealing configuration, and can comprehensively evaluate the annular pressure reduction effect of the screw pump 8 under different conditions, which helps to optimize the design and operating parameters of the pump and improve the performance and reliability of the pump.

[0067] The various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referenced to each other. Each embodiment focuses on the differences from other embodiments.

[0068] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit the present application. Although the present application has been described in detail with reference to the aforementioned embodiments, a person of ordinary skill in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some or all of the technical features thereof may be replaced by equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the present application.

Claims

1. A simulation experimental method for well depressurization and detection, characterized in that: Applicable to a simulation device, the simulation device comprising a mounting platform (1), a power part (2), a centrifugal pump (3), a variable frequency asynchronous motor (4), a mud circulation box (5), a power steering mechanism (6), a polished rod (7), a screw pump (8), a sleeve (9), a data acquisition instrument (10), a first sensor (11), a second sensor (12), and a third sensor (13); The power component (2), the centrifugal pump (3), the variable frequency asynchronous motor (4), and the mud circulation box (5) are all installed on the top of the installation platform (1); The output end of the power member (2) is connected to the centrifugal pump (3), and the input end of the centrifugal pump (3) is connected to the output end of the mud circulation box (5); The output end of the variable frequency asynchronous motor (4) is connected to a power steering mechanism (6), the power steering mechanism (6) is connected to a polished rod (7), one end of the polished rod (7) away from the power steering mechanism (6) passes through the mounting platform (1) and is connected to a screw pump (8), the axial direction of the polished rod (7) is perpendicular to the axial direction of the variable frequency asynchronous motor (4), and the power steering mechanism (6) is used to convert the rotational motion output by the variable frequency asynchronous motor (4) into the rotational motion of the polished rod (7) along the vertical direction; The sleeve (9) is installed at the bottom of the installation platform (1), the screw pump (8) is arranged in the sleeve (9), the inner wall of the sleeve (9) and the outer wall of the screw pump (8) form a gap, and the sleeve (9) and the screw pump (8) are concentric axes; An outer wall of the sleeve (9) is provided with an inlet (91) and an outlet (92), and the height of the inlet (91) is greater than the height of the outlet (92); The pipeline at the output end of the centrifugal pump (3) is connected to the inlet (91), and the inlet (91) is connected to the input flow channel of the screw pump (8); The pipe at the return end of the mud circulation box (5) is connected to the outlet (92); The pipeline at the return end of the mud circulation box (5) and the pipeline at the output end of the centrifugal pump (3) are respectively provided with a first stop valve (14) and a second stop valve (15); The method comprises: S1: injecting mud into the mud circulation box (5), starting the power part (2) to drive the centrifugal pump (3) to operate, the input end of the centrifugal pump (3) extracts mud medium from the mud circulation box (5), and conveys the mud to the screw pump (8) after pressurizing, and at the same time controls the output speed of the variable frequency asynchronous motor (4), drives the light rod (7) to rotate through the power steering mechanism (6), and at this time, appropriately opens the first stop valve (14) and the second stop valve (15) so that the mud can flow through the pipe at the output end of the centrifugal pump (3), the sleeve (9) and the pipe at the return end of the mud circulation box (5), so as to achieve the purpose of wetting and cleaning the simulation device; S2: The pressure changes of the first sensor (11), the second sensor (12) and the third sensor (13) are collected by the data acquisition instrument (10) until the mud fully fills the inside of the sleeve (9) and a small amount of mud returns to the mud circulation box (5); wherein the first sensor (11) is installed at the output end of the centrifugal pump (3) and is used to measure the medium pressure at the inlet (91); the second sensor (12) passes through the outer wall of the sleeve (9), extends into the gap, and is close to the return end of the mud circulation box (5) and is used to measure the medium pressure at the outlet (92); the third sensor (13) passes through the outer wall of the sleeve (9), extends into the gap, and is close to the bottom of the screw pump (8) and is used to measure the annular pressure of the sleeve (9), and the data acquisition instrument (10) is electrically connected to the first sensor (11), the second sensor (12) and the third sensor (13); S3: fully opening the first stop valve (14) and the second stop valve (15), and detecting the pressure changes of the first sensor (11), the second sensor (12), and the third sensor (13) again, while adjusting the rotation speed of the variable frequency asynchronous motor (4) until the pressures displayed by the first sensor (11), the second sensor (12), and the third sensor (13) are all stable, and then recording the pressure changes of the first sensor (11), the second sensor (12), and the third sensor (13) to evaluate the pressure reduction effect of the screw pump (8) on the annulus; S4: simulating different rotation speeds of the power component (2) and the variable frequency asynchronous motor (4) to observe and record the pressure reduction effect of the screw pump (8) on the annulus under different conditions, and simultaneously record the pressure changes of the first sensor (11), the second sensor (12) and the third sensor (13); S5: close the power component (2), the variable frequency asynchronous motor (4), the first stop valve (14) and the second stop valve (15), add new mud liquid containing solid particles into the mud circulation box (5), simulate the annular space pressure reduction effect of the screw pump (8) under different viscosities and densities, and repeat steps S1-S4.

2. The simulation experimental method for well depressurization and detection according to claim 1, characterized in that: In S2, the data acquisition instrument (10) is electrically connected to a computer data recording device (16), and the computer data recording device (16) is configured to record the pressure data collected by the data acquisition instrument (10) and convert the pressure data into a form representing the equivalent circulating density of the annulus of the screw pump (8). This conversion process will continue until a small amount of mud is observed to return to the mud circulation box (5).

3. The simulation experimental method for well depressurization and detection according to claim 1, characterized in that: In S3, slowly open the first stop valve (14) and the second stop valve (15) until they are fully opened; The threshold values ​​of the first stop valve (14) and the second stop valve (15) are both 0.18 MPa, and the rotation speed of the variable frequency asynchronous motor (4) is 2500 rpm.

4. The simulation experimental method for well depressurization and detection according to claim 1, characterized in that: A pipe at the output end of the centrifugal pump (3) passes through the mounting platform (1) and is connected to the inlet (91); The pipe at the return end of the mud circulation box (5) passes through the mounting platform (1) and is connected to the outlet (92).

5. The simulation experimental method for well depressurization and detection according to claim 1, characterized in that: The power component (2) is a three-phase asynchronous motor.

6. The simulation experimental method for well depressurization and detection according to claim 1, characterized in that: The power steering mechanism (6) includes a turbine and a worm gear; The output end of the variable frequency asynchronous motor (4) is connected to the worm; The worm is meshed with the turbine, and the smooth rod (7) is connected to the turbine via a square clip (20).

7. The simulation experimental method for well depressurization and detection according to claim 1, characterized in that: An anchor (17) is sleeved on the middle part of the outer wall of the screw pump (8); A labyrinth seal sleeve (18) or a mechanical seal sleeve (21) is sleeved on a side of the anchor (17) away from the screw pump (8).

8. The simulation experimental method for well depressurization and detection according to claim 1, characterized in that: One end of the bare rod (7) away from the power steering mechanism (6) is connected to a double universal joint rod (19), and one end of the double universal joint rod (19) away from the bare rod (7) is connected to a rotor of a screw pump (8).

9. The simulation experimental method for well depressurization and detection according to claim 7, characterized in that: After S5, it also includes: The power component (2), the variable frequency asynchronous motor (4), the first stop valve (14) and the second stop valve (15) are closed, and a mechanical sealing sleeve (21) or a labyrinth sealing sleeve (18) is used to simulate the annular pressure reduction effect of the screw pump (8) under different sealing conditions, and steps S1 to S5 are repeated.

Images