A tubular string vibration load tester and vibration load prediction method

Abstract

The application discloses a tubular string vibration load tester and a load prediction method, and relates to the technical field of downhole testing of oil and gas, wherein the tester comprises a test nipple, a temperature compensation sheet and a circuit board; the test nipple collects vibration acceleration data, pressure data and temperature data; a ground processing system calculates a total composite vibration load based on a transverse vortex-induced vibration load instantaneous value and a longitudinal vibration load, and performs temperature compensation on the total composite vibration load; and resonance risk judgment is also performed. The application can predict the transverse, longitudinal and composite vibration loads of the tubular string under different influencing factors, accurately determine the resonance risk, and thus comprehensively evaluate the safety performance of the tubular string.

Description

Technical Field

[0001] This application relates to the field of downhole testing technology for oil and gas, specifically to a tubing vibration load tester and a tubing vibration load prediction method based on fluid-structure interaction theory. Background Technology

[0002] With the continuous advancement of oil and gas exploration and development, the working conditions of oil and gas wells are complex and diverse. Under the action of fluid dynamics and structural coupling, the tubing string is prone to complex vibration phenomena such as lateral vibration, longitudinal vibration and torsional vibration.

[0003] Pipeline vibration causes periodic load changes in the pipeline structure, which, under long-term stress, can easily lead to fatigue damage, connection failure, or even pipeline fracture, seriously affecting the safety and production efficiency of oil and gas extraction operations. Therefore, accurate testing and real-time monitoring of pipeline vibration loads are important technical means to optimize pipeline structure design and suppress harmful vibrations.

[0004] Existing pipe column vibration testing equipment has many shortcomings: (1) The load measurement accuracy is low. Due to the lack of effective temperature compensation and signal stabilization measures, the sensor signal is easily interfered with under complex downhole conditions, making it difficult to accurately obtain the high-frequency dynamic characteristics of the pipe string vibration.

[0005] (2) Insufficient adaptability and maintainability. The existing equipment has a low degree of modularity, making installation and maintenance difficult. It is difficult to adapt to different specifications of tubing strings and has poor versatility.

[0006] Therefore, developing a high-precision and cost-effective pipe string vibration load tester, and further establishing a vibration load prediction method adapted to field conditions, is of great significance for improving the safety of oil and gas extraction operations and reducing extraction costs. Summary of the Invention

[0007] This application provides a tubing vibration load tester that can operate stably in conventional oil and gas well operations, enabling real-time monitoring of tubing vibration load parameters and improving the accuracy and reliability of vibration load testing. Another objective of this application is to provide a tubing vibration load prediction method based on fluid-structure interaction theory. By combining field monitoring data with a tubing dynamics model, the method can predict the trend of tubing vibration load changes.

[0008] On one hand, this application provides a pipe column vibration load tester, including a test section, a temperature compensation plate and a circuit board. The test section includes an outer cylinder and an inner cylinder, which are coaxially sleeved together to form a sealed installation space. The temperature compensation plate and the circuit board are disposed in the installation space. A vibration acceleration sensor, a pressure sensor and a temperature sensor are also disposed in the installation space. The circuit board is equipped with a microprocessor and a communication unit. The vibration acceleration sensor, pressure sensor, and temperature sensor form a bridge differential structure with the temperature compensation plate to eliminate the influence of temperature drift on measurement accuracy. The vibration acceleration data, pressure data, and temperature data collected by the vibration acceleration sensor, pressure sensor, and temperature sensor, respectively, are sent to the ground processing system via the microprocessor and communication unit. The ground processing system first calculates the peak value of the transverse vortex-induced vibration load, the transverse vortex-induced vibration frequency, and the natural frequency of the pipe column; then, it calculates the instantaneous value of the transverse vortex-induced vibration load based on the peak value and the transverse vortex-induced vibration frequency; next, it calculates the pressure wave angular frequency and calculates the thermal stress based on the temperature data; and calculates the longitudinal vibration load based on the pressure data, pressure wave angular frequency, and thermal stress; finally, it calculates the total composite vibration load based on the instantaneous value of the transverse vortex-induced vibration load and the longitudinal vibration load, and performs temperature compensation on the total composite vibration load according to the temperature data. The ground processing system also determines the actual vibration excitation frequency of the tubing based on vibration acceleration data, and then assesses the resonance risk based on the actual vibration excitation frequency and the natural frequency.

[0009] On the other hand, embodiments of this application also provide a method for predicting the vibration load of a tubular column, including: Vibration acceleration data, pressure data, and temperature data are collected. The vibration acceleration data, pressure data, and temperature data are collected by vibration acceleration sensors, pressure sensors, and temperature sensors, respectively. The vibration acceleration sensors, pressure sensors, and temperature sensors form a bridge differential structure with the temperature compensation plate to eliminate the influence of temperature drift on measurement accuracy. The vibration acceleration sensors, pressure sensors, and temperature sensors are integrated into the test section. First, the peak value of the transverse vortex-induced vibration load, the transverse vortex-induced vibration frequency, and the natural frequency of the tubing are calculated. Then, the instantaneous value of the transverse vortex-induced vibration load is calculated based on the peak value and the transverse vortex-induced vibration frequency. Next, the pressure wave angular frequency is calculated, and the thermal stress is calculated based on the temperature data. The longitudinal vibration load is calculated based on the pressure data, the pressure wave angular frequency, and the thermal stress. Finally, the total composite vibration load is calculated based on the instantaneous value of the transverse vortex-induced vibration load and the longitudinal vibration load, and temperature compensation is performed on the total composite vibration load according to the temperature data. The actual vibration excitation frequency of the tubing is determined based on vibration acceleration data, and then the resonance risk is assessed based on the actual vibration excitation frequency and the natural frequency.

[0010] The tubular vibration load tester and vibration load prediction method proposed in this application have the following advantages: This system can predict the lateral, longitudinal, and combined vibration loads of tubular columns under different influencing factors, accurately determine the resonance risk, and thus comprehensively assess the safety performance of the tubular columns. Experimental results show that the calculation results of this embodiment are highly consistent with the actual curve trends and numerical ranges, verifying the accuracy and practicality of the prediction calculation system proposed in this application. Attached Figure Description

[0011] 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 or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0012] Figure 1 This is a partial cross-sectional schematic diagram of the pipe column vibration load tester provided in the embodiments of this application.

[0013] Figure 2 This is a block diagram of the internal signal transmission of the column vibration load tester provided in an embodiment of this application.

[0014] Figure 3 The peak value of vortex-induced vibration load versus fluid velocity characteristic curve provided in the embodiments of this application.

[0015] Figure 4 The time-domain curves for predicting the total combined vibration load in the transverse, longitudinal, and composite directions are provided for embodiments of this application.

[0016] Figure 5 The curves showing the comparison of load prediction deviations before and after temperature compensation are provided for embodiments of this application.

[0017] Explanation of reference numerals: 1. Internal threaded connector; 2. First sealing ring; 3. Temperature compensation plate; 4. Outer cylinder; 5. Inner cylinder; 6. Circuit board; 7. Second sealing ring; 8. End cap; 9. External threaded connector. Detailed Implementation

[0018] 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 embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0019] Figure 1This is a schematic diagram of the structure of the pipe column vibration load tester provided in this embodiment of the application. The pipe column vibration load tester provided in this embodiment includes a test section, a temperature compensation plate 3, and a circuit board 6. The test section includes an outer cylinder 4 and an inner cylinder 5, which are coaxially sleeved together, forming a sealed installation space. The temperature compensation plate 3 and the circuit board 6 are disposed within the installation space. A vibration acceleration sensor, a pressure sensor, and a temperature sensor are also disposed within the installation space. Circuit board 6 is equipped with a microprocessor and a communication unit (i.e. Figure 2 (Data communication in the system) The vibration acceleration sensor, pressure sensor, and temperature sensor form a bridge differential structure with the temperature compensation plate 3 to eliminate the influence of temperature drift on measurement accuracy. The vibration acceleration data, pressure data, and temperature data collected by the vibration acceleration sensor, pressure sensor, and temperature sensor respectively are sent to the ground processing system via the microprocessor and communication unit. The ground processing system first calculates the peak value of the transverse vortex-induced vibration load, the transverse vortex-induced vibration frequency, and the natural frequency of the tubing; then it calculates the instantaneous value of the transverse vortex-induced vibration load based on the peak value of the transverse vortex-induced vibration load and the transverse vortex-induced vibration frequency; next, it calculates the pressure wave angular frequency and calculates the thermal stress based on the temperature data; and calculates the longitudinal vibration load based on the pressure data, pressure wave angular frequency, and thermal stress; finally, it calculates the total composite vibration load based on the instantaneous value of the transverse vortex-induced vibration load and the longitudinal vibration load, and performs temperature compensation on the total composite vibration load according to the temperature data. The ground processing system also determines the actual vibration excitation frequency of the tubing based on vibration acceleration data, and then assesses the resonance risk based on the actual vibration excitation frequency and the natural frequency.

[0020] For example, the temperature compensation plate 3 is a double compensation plate structure, which is fixed on the outer side of the inner cylinder 5. It can effectively eliminate the influence of temperature drift on measurement accuracy and ensure measurement accuracy under temperature influence.

[0021] The ground processing system includes a data receiving unit, a parameter calculation unit, and a display and early warning unit. The data receiving unit is connected to the communication unit in the test section via a dedicated communication cable. The parameter calculation unit is equipped with a parameter preset module, a data playback module, and an analysis and processing module.

[0022] The parameter preset module is used to set the sampling frequency, trigger conditions, acquisition duration, and data transmission mode; the data playback module realizes visualization of time-load-temperature curves, data filtering, storage, and printout control, automating the entire process of signal acquisition, storage, and transmission, with convenient operation and high data processing efficiency; the analysis and processing module is the core of this application, which focuses on introducing a dual-function prediction of "real-time monitoring + trend prediction". The prediction calculation system is based on fluid-structure interaction theory, tubular dynamic characteristics, and on-site working parameters, which can accurately predict vibration load peaks, frequency changes, and resonance risks; the display and early warning unit is used to display the final calculation results and issue early warnings when necessary.

[0023] The outer cylinder 4 adopts a composite structure of body + inner lining reinforcement layer, where the body wall thickness is 8mm and the inner lining reinforcement layer wall thickness is 2mm; the maximum outer diameter of the test short section is 140mm and the minimum inner diameter is 50mm, which is compatible with sleeves of Φ177.8mm and above. The installation space between the inner cylinder 5 and the outer cylinder 4 is greater than 20mm on one side, which can not only meet the flow requirements of the fluid channel inside the inner cylinder 5, but also provide sufficient space for electronic components and power supply.

[0024] The inner cylinder 5 and outer cylinder 4 are made of 40CrNiMoA high-strength alloy steel, and the inner lining reinforcement layer of the outer cylinder 4 is made of WC-9Ni high-strength alloy. The surfaces of the inner cylinder 5, outer cylinder 4 and inner lining reinforcement layer are all treated with bluing process, which combines high strength, high hardness and excellent corrosion resistance, and can resist the erosion of corrosive media such as downhole H2S, CO2 and high-mineralization formation water.

[0025] The vibration acceleration sensor, pressure sensor, temperature sensor, and all electronic components on circuit board 6 are industrial-grade wide-temperature components, which can adapt to the ambient temperature changes of routine downhole operations, while also having excellent cost performance.

[0026] Circuit board 6 is also equipped with a signal conditioning unit and an A / D conversion unit. The signal conditioning unit and the A / D conversion unit respectively condition and convert the electrical signals generated by the vibration acceleration sensor, pressure sensor and temperature sensor into analog-to-digital data to form vibration acceleration data, pressure data and temperature data, which are finally transmitted to the microprocessor.

[0027] like Figure 2 As shown, the signal transmission path of the test section is as follows: the sensor collects vibration acceleration, pressure and temperature signals → the signal conditioning unit amplifies and filters the signals → the A / D conversion unit completes the analog-to-digital conversion → the microprocessor processes and calculates the signals → the storage unit stores the signals locally / the communication unit transmits the signals to the ground processing system.

[0028] In the embodiments of this application, the circuit board 6 is further provided with a data storage unit, which is used to store vibration acceleration data, pressure data and temperature data received by the microprocessor.

[0029] In the embodiments of this application, the inner cylinder 5 is provided with an internal threaded connector 1 and an external threaded connector 9 at both ends.

[0030] Both internal thread connector 1 and external thread connector 9 use trapezoidal LTC bidirectional threads with thread parameters of 8TPI pitch, 3 / 4 inch / foot taper, total length 60mm, and effective engagement 45mm. They are compatible with common specifications of oil tubing materials such as N80, P110, and L80. The thread type at both ends of the test sub is a gas-tight 3.5-inch 3SB tubing thread, with one end being external and the other internal. Connections between the test sub and other tubing strings can be achieved using variable thread connectors. The connection surface provides good sealing performance and can withstand the impact of downhole fluids.

[0031] In the embodiments of this application, after the outer cylinder 4 is coaxially sleeved on the outside of the inner cylinder 5, the outer cylinder 4 is fastened by the end cap 8, and the end cap 8 is locked to one end of the inner cylinder 5 by a positioning screw.

[0032] In the embodiments of this application, the inner cylinder 5 is provided with a first sealing ring 2 and a second sealing ring 7 on the outer side near both ends. When the outer cylinder 4 is sleeved on the outer side of the inner cylinder 5, the first sealing ring 2 and the second sealing ring 7 are in close contact with the two ends of the inner side of the outer cylinder 4, forming a sealed installation space.

[0033] In addition, the installation space is equipped with a power supply and a corresponding power control board. The power supply is a battery pack, which is used to power the circuit boards and sensors in the installation space.

[0034] Both the first sealing ring 2 and the second sealing ring 7 are O-ring structures.

[0035] In the embodiments of this application, the inner side of the outer cylinder 4 is provided with multiple protective plates, and the vibration acceleration sensor, pressure sensor and temperature sensor are respectively disposed on the protective plates.

[0036] The protective plate forms a burr structure on the inner side of the outer cylinder 4. The protective plate is made of high-strength alloy steel and is riveted to the outer cylinder 4. It can provide mechanical collision protection for the sensor and also serve as an auxiliary installation platform for electronic components.

[0037] In the embodiments of this application, the process by which the ground processing system calculates the total composite vibration load and performs temperature compensation is as follows: In transverse vibration, vortex-induced vibration is the main cause of fatigue damage to the tubing, and its peak load directly determines the degree of damage. The peak load of transverse vortex-induced vibration is: (1) in, The value represents the peak value of the transverse vortex-induced vibration load, in kN. The lateral dynamic lift coefficient is dimensionless. Fluid density, in kg / m³; The fluid velocity inside the tubing is expressed in m / s. The outer diameter of the tubular column is in meters (m). The span of the tubular centralizer is in meters (m).

[0038] To accurately obtain the excitation frequency of vortex-induced vibration and provide a basis for resonance judgment, the transverse vortex-induced vibration frequency is: (2) in, The transverse vortex-induced vibration frequency is expressed in Hz. The Strauhal number is dimensionless, and the subcritical Reynolds number is taken as 0.25 under turbulent conditions.

[0039] To obtain dynamic load data of transverse vortex-induced vibration at different time points and support accurate calculation of the total load of the combined vibration, the instantaneous value of the transverse vortex-induced vibration load is: (3) in, The instantaneous value of the transverse vortex-induced vibration load at time t, in kN; Time, in seconds; The initial phase angle is expressed in rad.

[0040] Longitudinal vibration is mainly caused by the superposition of pressure transients (water hammer effect) and thermal stress. Its dynamic load changes directly affect the reliability of the threaded connection of the tubing and the axial fatigue life. To accurately describe the dynamic propagation law of the pressure wave, the pressure wave angular frequency is: (4) in, The pressure wave angular frequency is expressed in rad / s. The propagation velocity of the fluid pressure wave inside the pipe is expressed in m / s. This data is determined based on vibration acceleration data collected by a vibration acceleration sensor. The depth of the tubing string, in meters (m).

[0041] Temperature changes cause significant thermal stress in the tubing, which, when superimposed with vibration stress, exacerbates fatigue damage. The thermal stress is: (5) in, The axial thermal stress of the tubing is expressed in MPa. The axial constraint coefficient is dimensionless. The elastic modulus of the tubular material is expressed in MPa. The coefficient of thermal expansion of the material is expressed in °C. -1 ; This represents the temperature difference between the wellbore and ambient temperature, in °C. This data is based on temperature data collected by temperature sensors and surface calibration temperatures. Sure.

[0042] The longitudinal vibration load needs to comprehensively consider the pressure fluctuation attenuation characteristics, pressure wave propagation law, and thermal stress superposition effect. The longitudinal vibration load is: (6) in, The longitudinal vibration load at time t is expressed in kN. The effective cross-sectional area of ​​the tubular column is expressed in meters (m²). 2 ; This is the initial pressure fluctuation amplitude, in MPa. This data is determined based on the pressure data collected by the pressure sensor. The pressure attenuation coefficient is expressed in seconds. -1 ; The phase angle is expressed in rad.

[0043] In actual operation, the transverse and longitudinal vibrations of the tubing are not independent but coupled to form a composite vibration. The total load of this composite vibration directly determines the actual stress state and fatigue life of the tubing. Therefore, the total load of the composite vibration is: (7) in, The total combined vibration load at time t is expressed in kN.

[0044] Temperature can cause sensor signal drift and changes in material parameters, directly affecting the accuracy of load prediction. Therefore, a temperature compensation and correction mechanism needs to be constructed. The temperature correction formula in this embodiment is as follows: (8) in, The predicted load is after temperature correction, in kN. This is a temperature correction factor, in °C. -1 ; The actual downhole temperature is expressed in °C and is obtained from a temperature sensor. The temperature is calibrated for the ground, in °C.

[0045] In the embodiments of this application, the natural frequency of the tubing is the core benchmark for judging the risk of resonance. It needs to be accurately calculated by combining the tubing material properties, geometric parameters, and fluid-added mass effects. The natural frequency includes the transverse natural frequency and the longitudinal natural frequency of the tubing. The transverse natural frequency is: (9) in, Let be the transverse natural frequency of the tubular column at the j-th order, in Hz; Let be the modal eigenvalue of order j, which is dimensionless; The elastic modulus of the tubular material is expressed in Pa. The moment of inertia of the tubular section is expressed in meters (m). 4 ; The equivalent mass per unit length of the tubular string, expressed in kg / m; The span of the tubular centralizer is in meters (m).

[0046] Resonance is a key risk source leading to sudden failure of tubing. A scientific assessment mechanism needs to be established, based on the matching relationship between the actual vibration frequency and the natural frequency of the tubing, to provide early warning of resonance risk. The process of the ground-based treatment system assessing resonance risk is as follows: (10) in, The actual vibration excitation frequency is given in Hz. For transverse vibration, the transverse vortex-induced vibration frequency is used, and for longitudinal vibration, the pressure wave excitation frequency is used. The natural frequency of the tubing in the corresponding direction is Hz, i.e., the transverse natural frequency or the longitudinal natural frequency. If the above conditions are met, the ground handling system will trigger an audible and visual warning to prompt the operator to adjust the production parameters or take vibration reduction measures in a timely manner to avoid the risk of tubing failure caused by resonance.

[0047] like Figure 1-2 As shown, the tubing vibration load tester of this application includes a surface processing system and a downhole load testing system that communicate with each other. The core of the downhole load testing system is the test sub. The inner cylinder 5 is a strain gauge, forming a sealed annular cavity with a single-sided dimension greater than 20mm between it and the outer cylinder 4. This annular cavity houses sensors, circuit boards, and power supplies, providing installation space for electronic components and achieving physical isolation to protect the strain gauges from downhole fluid corrosion. In this embodiment, the microprocessor is also connected to an LCD screen and buttons, which are used for on-site parameter setting, sampling status display, working mode switching, and fault / early warning information prompts.

[0048] The sealing structure inside the test section includes a sealing ring, an end cap 8, and a positioning screw. The sealing ring includes a first sealing ring 2 and a second sealing ring 7. The two sealing rings are respectively set at both ends of the outer side of the inner cylinder 5, and each has two rings. Under external pressure conditions, the sealing ring is self-tightened by the compression of the outer cylinder 4. Under internal pressure conditions, it forms a dynamic seal by the expansion of the strain tube. The end cap 8 and the positioning screw can effectively prevent the axial displacement of the outer cylinder 4 and ensure the sealing stability.

[0049] Temperature compensation plates, combined with the characteristics of the bridge and differential circuit, can eliminate the influence of temperature effect on the measurement accuracy of the sensor. They can accurately collect vibration parameters in the range of 5Hz~50Hz vortex-induced vibration and 0.015Hz~0.1Hz tubing natural frequency, as well as wellbore pressure and temperature data.

[0050] Example Taking a certain well as a field application example, the well was drilled to a depth of 3500m, with a bottom hole temperature of 125℃, a pressure of approximately 52MPa, and crude oil as the fluid. It was fitted with a Φ73mm×5.51mm P110 tubing. This study verifies the accuracy and practicality of the predictive calculation system presented in this application. All calculation results are consistent with… Figure 3-5 The curve trends and numerical ranges are highly consistent.

[0051] Pre-well entry parameter input: outer diameter of tubing string , pipe string inner diameter Depth of tubing insertion Temperature-corrected elastic modulus of tubular material (Temperature 125°C), density of tubular material First-order modal eigenvalues Additional quality coefficient Initial phase angle Ground calibration temperature .

[0052] Real-time monitoring data: fluid velocity inside the tubing fluid density Lateral dynamic lift coefficient Strauhall number The propagation speed of pressure waves in the pipe Initial pressure fluctuation amplitude Pressure attenuation coefficient Axial constraint coefficient Coefficient of thermal expansion of material Temperature difference between underground and ambient temperature Temperature correction factor Actual temperature downhole Calculate time .

[0053] The specific calculation process is as follows: (1) Prediction of peak value of transverse vortex-induced vibration load. According to formula (1), substituting the corresponding parameters, we get:

[0054] (2) Calculation of transverse vortex-induced vibration frequency. According to formula (2), substituting the corresponding parameters, we get:

[0055] (3) Calculation of instantaneous value of transverse vortex-induced vibration load (t=1s). According to formula (3), substituting the corresponding parameters of the calculation results of formulas (1) and (2) yields:

[0056] (4) Calculation of pressure wave angular frequency. According to formula (4), substituting the corresponding parameters, we get:

[0057] (5) Thermal stress calculation. According to formula (5), substituting the corresponding parameters, we get:

[0058] (6) Calculation of longitudinal vibration load (t=1s). According to formula (6), first calculate the effective cross-sectional area of ​​the pipe column, and then substitute the calculation results and corresponding parameters of formulas (4) and (5) to obtain:

[0059] (7) Calculation of total composite vibration load (t=1s). According to formula (7), substituting the calculation results of formulas (3) and (6), we get:

[0060] (8) Temperature compensation correction. According to formula (8), substituting the corresponding parameters, we get:

[0061] Judgment result: Not entered the resonance risk zone, no resonance warning needs to be triggered.

[0062] (9) Calculation of the transverse natural frequency of the tubular column. According to formula (9), first calculate the moment of inertia of the tubular section and the equivalent mass per unit length, and substitute the corresponding parameters to obtain:

[0063] (10) Resonance risk assessment.

[0064] Lateral resonance risk assessment: The actual vibration excitation frequency under lateral vibration conditions is taken as the lateral vortex-induced vibration frequency, i.e. Horizontal natural frequency of the tubing .

[0065] Substitute into the judgment formula (10): .

[0066] The assessment result is: no risk of lateral resonance.

[0067] Longitudinal resonance risk assessment: The actual vibration excitation frequency under longitudinal vibration conditions is taken as the longitudinal pressure wave excitation frequency, which is converted from the pressure wave angular frequency. Calculated according to Formula 4 , 0.0857Hz, therefore the longitudinal natural frequency of the tubing is .

[0068] Substitute into the judgment formula (10): .

[0069] The assessment result is: no risk of longitudinal resonance.

[0070] Figure 3 The curve is a quantitative analysis of the peak value prediction results of the transverse vortex-induced vibration load proposed in this application. The horizontal axis represents the actual fluid velocity (unit: m / s), and the vertical axis represents the peak value of the vortex-induced vibration load (unit: kN). The curve variation law is highly consistent with the theoretical derivation of the prediction model proposed in this application. It intuitively shows the influence trend of fluid velocity on the transverse vortex-induced vibration load of the tubing. It can be directly used for the prediction of transverse fatigue risk of tubing under different flow velocity conditions. It provides accurate quantitative basis for setting load warning thresholds and adjusting fluid flow rate on site, and effectively verifies the accurate prediction capability of the prediction model proposed in this application for vortex-induced vibration load.

[0071] Figure 4 The figure shows the dynamic quantitative analysis curve of the predicted total composite vibration load. The horizontal axis represents time (in seconds), and the vertical axis represents the vibration load (in kN). The figure presents the dynamic changes of the transverse vortex-induced vibration load, the longitudinal vibration load, and the total composite vibration load under the coupling effect of the two on time. The curve clearly shows the phase difference and coupling superposition effect of the transverse and longitudinal vibrations. The total composite vibration load can accurately restore the actual stress state of the tubing under downhole working conditions. Compared with the traditional single-direction load prediction method, it is more in line with engineering practice and can provide accurate quantitative data support for tubing fatigue life assessment and tubing structure optimization design.

[0072] Figure 5 The graph shows the accuracy verification curve of the temperature-compensated correction model. The horizontal axis represents the actual downhole temperature (unit: °C), and the vertical axis represents the relative deviation of load prediction (unit: %). It visually compares the changes in load prediction deviation under two conditions: no temperature compensation and the temperature compensation mechanism proposed in this application. The curve shows that without temperature compensation, the load prediction deviation increases significantly with increasing downhole temperature. After adopting the temperature compensation structure and correction algorithm proposed in this application, the load prediction deviation can be stably controlled within a low level range. This figure effectively verifies the effectiveness of the temperature compensation structure and correction algorithm of this invention, eliminating the interference of temperature-induced sensor signal drift and material parameter changes on prediction accuracy, and demonstrating the practicality and reliability of the vibration load prediction method proposed in this application under the influence of downhole temperature.

[0073] This application also provides a method for predicting the vibration load on a tubular column, the method comprising: Vibration acceleration data, pressure data, and temperature data are collected. The vibration acceleration data, pressure data, and temperature data are collected by vibration acceleration sensor, pressure sensor, and temperature sensor, respectively. The vibration acceleration sensor, pressure sensor, and temperature sensor form a bridge differential structure with temperature compensation plate 3 to eliminate the influence of temperature drift on measurement accuracy. The vibration acceleration sensor, pressure sensor, and temperature sensor are integrated in the test section. First, the peak value of the transverse vortex-induced vibration load, the transverse vortex-induced vibration frequency, and the natural frequency of the tubing are calculated. Then, the instantaneous value of the transverse vortex-induced vibration load is calculated based on the peak value and the transverse vortex-induced vibration frequency. Next, the pressure wave angular frequency is calculated, and the thermal stress is calculated based on the temperature data. The longitudinal vibration load is calculated based on the pressure data, the pressure wave angular frequency, and the thermal stress. Finally, the total composite vibration load is calculated based on the instantaneous value of the transverse vortex-induced vibration load and the longitudinal vibration load, and temperature compensation is performed on the total composite vibration load according to the temperature data. The actual vibration excitation frequency of the tubing is determined based on vibration acceleration data, and then the resonance risk is assessed based on the actual vibration excitation frequency and the natural frequency.

[0074] Although preferred embodiments of this application have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this application.

[0075] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. Therefore, if such modifications and variations fall within the scope of the claims of this application and their equivalents, this application also intends to include such modifications and variations.

Claims

1. A pipe column vibration load tester, characterized in that, The test section includes a test section, a temperature compensation plate (3), and a circuit board (6). The test section includes an outer cylinder (4) and an inner cylinder (5). The outer cylinder (4) and the inner cylinder (5) are coaxially sleeved together, forming a sealed installation space between them. The temperature compensation plate (3) and the circuit board (6) are disposed in the installation space. A vibration acceleration sensor, a pressure sensor, and a temperature sensor are also disposed in the installation space. The circuit board (6) is equipped with a microprocessor and a communication unit. The vibration acceleration sensor, the pressure sensor, and the temperature sensor form a bridge differential structure with the temperature compensation plate (3) to eliminate the influence of temperature drift on the measurement accuracy. The vibration acceleration data, pressure data, and temperature data collected by the vibration acceleration sensor, the pressure sensor, and the temperature sensor are respectively sent to the ground processing system via the microprocessor and the communication unit. The ground processing system first calculates the peak value of the transverse vortex-induced vibration load, the transverse vortex-induced vibration frequency, and the natural frequency of the pipe column; then it calculates the instantaneous value of the transverse vortex-induced vibration load based on the peak value of the transverse vortex-induced vibration load and the transverse vortex-induced vibration frequency; next, it calculates the pressure wave angular frequency based on the vibration acceleration data, and calculates the thermal stress based on the temperature data; it calculates the longitudinal vibration load based on the pressure data, the pressure wave angular frequency, and the thermal stress; finally, it calculates the total composite vibration load based on the instantaneous value of the transverse vortex-induced vibration load and the longitudinal vibration load, and performs temperature compensation on the total composite vibration load according to the temperature data. The ground processing system also determines the actual vibration excitation frequency of the tubing based on the vibration acceleration data, and then assesses the resonance risk based on the actual vibration excitation frequency and the natural frequency.

2. The string vibration load tester of claim 1, wherein, The circuit board (6) is also provided with a signal conditioning unit and an A / D conversion unit. The signal conditioning unit and the A / D conversion unit respectively condition and convert the electrical signals generated by the vibration acceleration sensor, the pressure sensor and the temperature sensor to form the vibration acceleration data, the pressure data and the temperature data, and finally transmit them to the microprocessor.

3. A string vibration load tester according to claim 2, wherein, The circuit board (6) is also provided with a data storage unit, which is used to store the vibration acceleration data, pressure data and temperature data received by the microprocessor.

4. The string vibration load tester of claim 1, wherein, The inner cylinder (5) is provided with an internal threaded connector (1) and an external threaded connector (9) at both ends.

5. The string vibration load tester of claim 1, wherein, After the outer cylinder (4) is coaxially sleeved on the outside of the inner cylinder (5), the outer cylinder (4) is fastened by the end cap (8), and the end cap (8) is locked to one end of the inner cylinder (5) by the positioning screw.

6. A string vibration load tester according to claim 5, wherein, The inner cylinder (5) is provided with a first sealing ring (2) and a second sealing ring (7) on its outer side near both ends. When the outer cylinder (4) is fitted onto the outer side of the inner cylinder (5), the first sealing ring (2) and the second sealing ring (7) are in close contact with the two ends of the inner side of the outer cylinder (4) to form a sealed installation space.

7. The string vibration load tester of claim 1, wherein, The inner side of the outer cylinder (4) is provided with multiple protective plates, and the vibration acceleration sensor, the pressure sensor and the temperature sensor are respectively disposed on the protective plates.

8. The string vibration load tester of claim 1, wherein, The process by which the ground treatment system calculates the total composite vibration load and performs temperature compensation is as follows: The peak value of the transverse vortex-induced vibration load is: in, The peak value of the transverse vortex-induced vibration load. The lateral dynamic lift coefficient. For fluid density, The fluid velocity inside the tubing is [value]. The outer diameter of the tubular column, The span of the tubular centralizer; The transverse vortex-induced vibration frequency is: wherein is the vortex shedding frequency, is the Strouhal number; The instantaneous value of the transverse vortex-induced vibration load is: wherein, is the instantaneous value of the transverse vortex-induced vibration load at time t, is time, is the initial phase angle; The angular frequency of the pressure wave is: wherein, is the pressure wave angular frequency, is the fluid pressure wave propagation speed in the pipe, is the pipe string depth; The thermal stress is: in, The thermal stress is axial in the tubular column. This is the axial constraint coefficient. The elastic modulus of the tubular material. The coefficient of thermal expansion of the material. The temperature difference between the underground well and room temperature; The longitudinal vibration load is: in, The longitudinal vibration load at time t, The effective cross-sectional area of ​​the tubular column, This represents the initial pressure fluctuation amplitude. The pressure attenuation coefficient is... The phase angle; The total load of the composite vibration is: wherein, Ft is the total complex vibration load at time t; The temperature correction formula is: wherein, is the temperature corrected predicted load, is the temperature correction coefficient, is the actual downhole temperature, is the surface calibration temperature.

9. The string vibration load tester of claim 1, wherein, The natural frequencies include the transverse natural frequency and the longitudinal natural frequency of the tubing, wherein the transverse natural frequency is: in, Let be the transverse natural frequency of the tubular column at the j-th order. Let j be the modal eigenvalue of order j. The elastic modulus of the tubular material. Let be the moment of inertia of the tubular section. The equivalent mass per unit length of the tubular string. The span of the tubular stabilizer; The process by which the ground processing system determines the risk of resonance is as follows: in, The actual vibration excitation frequency is used; for transverse vibration, the transverse vortex-induced vibration frequency is used, and for longitudinal vibration, the pressure wave excitation frequency is used. The natural frequency corresponding to the direction of the tube column is either the transverse natural frequency or the longitudinal natural frequency; if the above conditions are met, the ground processing system triggers an audible and visual warning.

10. A load prediction method applied to the string vibration load tester according to any one of claims 1 to 9, characterized in that, include: Vibration acceleration data, pressure data and temperature data are collected, wherein the vibration acceleration data, the pressure data and the temperature data are collected by vibration acceleration sensor, pressure sensor and temperature sensor respectively, and the vibration acceleration sensor, the pressure sensor and the temperature sensor form a bridge differential structure with temperature compensation plate (3) respectively to eliminate the influence of temperature drift on measurement accuracy. The vibration acceleration sensor, the pressure sensor and the temperature sensor are integrated in the test section; First, the peak value of the transverse vortex-induced vibration load, the transverse vortex-induced vibration frequency, and the natural frequency of the tubing are calculated. Then, the instantaneous value of the transverse vortex-induced vibration load is calculated based on the peak value and the transverse vortex-induced vibration frequency. Next, the pressure wave angular frequency is calculated, and the thermal stress is calculated based on the temperature data. The longitudinal vibration load is calculated based on the pressure data, the pressure wave angular frequency, and the thermal stress. Finally, the total composite vibration load is calculated based on the instantaneous value of the transverse vortex-induced vibration load and the longitudinal vibration load, and temperature compensation is performed on the total composite vibration load according to the temperature data. The actual vibration excitation frequency of the tubing is determined based on the vibration acceleration data, and then the resonance risk is assessed based on the actual vibration excitation frequency and the natural frequency.

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