Oil casing sealing performance detection method and detection system

Abstract

The invention relates to the technical field of oil and gas field development, in particular to an oil casing sealing performance detection method and system. The oil casing sealing performance detection method comprises the following steps: selecting a sealing joint sample, calibrating a function relationship between stress and an ultrasonic reflection coefficient of the sealing joint sample under different torques, and calibrating a corresponding relationship between stress and sealing performance of the sealing joint sample under the same torque and different sealing performance; and establishing a numerical relationship model associated with the ultrasonic reflection coefficient and the sealing performance, obtaining the ultrasonic reflection coefficient on the sealing end face of the in-well oil casing, and outputting the sealing performance corresponding to the in-well oil casing through the numerical relationship model. According to the method, the sealing performance of the sealing end face of the oil casing can be rapidly evaluated by detecting the ultrasonic reflection coefficient of the oil casing entering the well, the accuracy and reliability of sealing evaluation can be optimized and improved based on the advantages of ultrasonic detection, the detection time is greatly shortened, and a more comprehensive and reliable basis is provided for evaluation of the connection quality of the oil casing.

Description

Technical Field

[0001] This invention relates to the field of oil and gas field development technology, and in particular to a method and system for testing the sealing performance of oil casing. Background Technology

[0002] Xinjiang Oilfield The enhanced oil recovery (EOR) test is running in seven blocks, among which the annular pressure problem in the gas injection wells is prominent, accounting for 75%, which easily leads to leakage of the well tubing and poses a safety risk to production. Existing... To address the leakage problem of the tubing string during well entry, a gas-tight seal is installed on the sealing end face of the tubing string. However, due to issues with the quality of the gas-tight seal itself and the inaccurate operation during installation, the gas-tight seal often fails to seal properly, making leakage still possible at the sealing end face of the tubing string. Therefore, it is necessary to conduct a gas-tightness test before the tubing string is inserted into the well to eliminate leakage caused by inadequate sealing of the gas-tight seal.

[0003] Currently, in the early stages of oilfield recovery, such as in the 530 well area of ​​Zone 8... In the pilot test area, only two wells underwent helium testing for airtightness. However, due to the long testing cycle (at least 40 hours per well), complex equipment operation, and high cost, subsequent wells were not tested for airtightness. This resulted in subsequent wells only having their airtight connections tightened to the recommended torque, making it impossible to effectively assess the sealing performance of the tubing, posing a significant safety hazard. Therefore, there is an urgent need to develop a rapid, accurate, and low-cost method for testing the sealing performance of tubing strings. Summary of the Invention

[0004] The purpose of this invention is to provide a method and system for testing the sealing performance of oil casing and tubing, so as to solve the problem that the sealing performance of oil casing and tubing in the well cannot be quickly and effectively determined in the prior art.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: This invention discloses a method for testing the sealing performance of oil casing, comprising: A sample of the sealing joint was selected by simulating the actual working conditions of the gas-tight seal and the casing in the well. The stress and ultrasonic reflection coefficient of the sealing joint sample under different torques were obtained, and the functional relationship between stress and ultrasonic reflection coefficient was calibrated. Obtain the stress of the sealing joint sample under the same torque but with different sealing performance, and calibrate the relationship between stress and sealing performance; Based on the functional relationship between stress and ultrasonic reflection coefficient, and the correspondence between stress and sealing performance, a numerical relationship model relating ultrasonic reflection coefficient and sealing performance is established. The ultrasonic reflection coefficient on the sealing end face of the casing and tubing entering the well is obtained, and the sealing performance of the casing and tubing entering the well is output through a numerical relationship model.

[0006] Optionally, the method for obtaining the stress of the sealing joint sample under different torques includes: Based on the mechanical analysis of the gas seal and casing under actual downhole working conditions, a stress calculation model is established at the sealing end face of the casing under standard torque. Select a sealing joint sample and apply torque to the sealing joint sample; Starting from a preset initial torque, gradually increase the applied torque and record the torque value after each increase; Based on the recorded torque values, the stress corresponding to different torque values ​​is calculated sequentially using the established stress calculation model.

[0007] Optionally, the method for establishing a stress calculation model at the sealing end face of the casing under standard torque, based on the mechanical analysis of the gas-tight seal and the casing under actual downhole operating conditions, includes: Based on the mechanical analysis of the gas seal and the casing under actual downhole conditions, the standard model parameters of the casing and the stress parameters at the sealing end face of the casing and the casing under actual conditions are obtained. A three-dimensional model of the oil casing is established through numerical simulation, and material properties are defined in the established three-dimensional model. Determine the boundary conditions and loading method of the 3D model, and apply standard torque; Numerical simulations were run to calculate the stress and strain distribution at the sealing end face of the oil casing under standard torque. A stress calculation model for the sealing end face of the oil casing under standard torque is established based on the calculated stress and strain distribution.

[0008] Optionally, the method for obtaining the ultrasonic reflection coefficient of the sealing joint sample under different torques includes: Ultrasonic waves are emitted onto the selected sealing joint sample; According to the pulse reflection method, the reflected wave signal reflected back from the sealing joint sample after each increase in torque is recorded; The recorded reflected wave signals are processed and analyzed, and the ultrasonic reflection coefficients corresponding to different torque values ​​are calculated based on the amplitude ratio of the reflected wave signals to the preset reference signals.

[0009] Optionally, the method for obtaining the stress of the sealing joint sample under the same torque but with different sealing performance includes: Multiple sealing joint samples with different sealing performance were selected and assigned to different test groups. The same torque was applied to the sealing joint specimens of each test group, and the applied torque value was recorded; Based on the recorded torque values, the stress corresponding to each test group was calculated using the established stress calculation model.

[0010] Optionally, the method for determining the correspondence between the calibrated stress and the sealing performance includes: Starting from the preset initial torque, gradually increase the torque applied to each test group, and ensure that the torque increase is the same for each test group each time; Record the torque value of each test group after each increase, and calculate the stress corresponding to each test group at different torque values ​​in turn using the established stress calculation model. Based on the recorded different torque values, the stress and sealing performance of each test group were analyzed and calibrated by comparing the stress at the same torque value.

[0011] Optionally, the method for selecting multiple sealing joint samples with different sealing performance includes: Based on the sealing performance characterized by a high degree of sealing, a sealing joint sample was selected that simulated complete contact between the gas-tight buckle and the sealing end face of the oil casing. Based on the sealing performance characterized by moderate sealing degree, a sealing joint sample was selected that simulated the presence of particles between the gas seal buckle and the sealing end face of the oil casing or the spacing was less than the preset distance. Based on the sealing performance characterized by low sealing degree, sealing joint samples with defects or a gap greater than the preset distance between the simulated gas seal buckle and the sealing end face of the oil casing were selected.

[0012] Optionally, the method for obtaining the ultrasonic reflection coefficient on the sealing end face of the well casing and outputting the corresponding sealing performance of the well casing through a numerical relationship model includes: The sealing end face of the casing pipe entering the well was tested using ultrasonic testing equipment, and the ultrasonic reflection coefficient on the sealing end face of the casing pipe entering the well was recorded by pulse reflection method. The recorded ultrasonic reflection coefficients are input into the numerical relationship model, and the sealing performance of the well casing is output. If the output indicates a high degree of sealing performance, then it can be determined that there is no safety hazard in the gas tightness of the casing and tubing entering the well. If the output indicates a moderate sealing performance, it is judged that there is a general safety hazard in the gas tightness of the casing in the well. If the output indicates a low sealing performance, it is determined that there is an urgent safety hazard in the gas tightness of the casing and tubing entering the well.

[0013] Optionally, the method for selecting sealing joint samples by simulating the actual working conditions of the gas-tight seal and casing downhole includes: The parameters and conditions for the simulation test were determined based on the actual working conditions of the gas seal and the casing downhole. Based on the material properties of the gas-tight seal and the oil casing, multiple sets of sealing joint samples were prepared by selecting appropriate materials. Multiple groups of sealing joint samples were simulated under determined parameters and conditions, and the parameter data of each group of sealing joint samples were recorded during the simulation test. By comparing the parameter data of different groups of sealing joint samples, the sealing joint sample that meets the preset sealing performance requirements is selected.

[0014] This invention also discloses a testing system that employs the above-mentioned method for testing the sealing performance of oil casing, comprising: A torque application module, connected to the gas seal buckle, is used to apply torque to the gas seal buckle; An ultrasonic testing module, in contact with the gas-tight buckle, is used to emit ultrasonic waves to the sealing end face of the oil casing and to receive the reflected wave signal reflected back from the sealing end face of the oil casing. The data analysis module interfaces with the ultrasonic detection module to acquire the reflected wave signal received by the ultrasonic detection module and to obtain the ultrasonic reflection coefficient based on the reflected wave signal analysis. The input / output module interfaces with the data analysis module to input the ultrasonic reflection coefficient and output the sealing performance of the oil casing through a numerical relationship model.

[0015] Compared with the prior art, the beneficial effects of the oil casing sealing performance testing method and testing system provided in this embodiment of the invention are as follows: By simulating the actual working conditions of the gas-tight joint and the casing in the well, sealing joint samples were selected. The stress magnitude of the sealing joint samples under different torques was obtained, and the ultrasonic reflection coefficient corresponding to different torques was obtained using the pulse reflection method. Thus, the functional relationship between stress and ultrasonic reflection coefficient was obtained. Then, by measuring the stress magnitude of sealing joint samples with different sealing performance under the same torque, the relationship between stress and casing sealing performance was obtained. By combining the above two relationships, a numerical relationship model relating ultrasonic reflection coefficient and sealing performance can be established. Thus, the numerical relationship model can be used to quickly evaluate the sealing performance of the casing sealing end face by detecting the ultrasonic reflection coefficient of the casing in the well. Based on the advantages of ultrasonic testing, the accuracy and reliability of sealing evaluation can be optimized and improved, and the testing time can be greatly shortened, providing a more comprehensive and reliable basis for evaluating the quality of casing connection. Attached Figure Description

[0016] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. In the accompanying drawings: Figure 1 This is a schematic block diagram illustrating the steps of the oil casing sealing performance testing method provided in an embodiment of the present invention; Figure 2A structural diagram of the device for measuring the stress and ultrasonic reflection coefficient of a sealed joint sample provided in an embodiment of the present invention.

[0017] The labels for the attached figures are as follows: 1. Sealing joint sample; 2. Torque application module; 3. Ultrasonic testing module. Detailed Implementation

[0018] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0019] This invention discloses a method for testing the sealing performance of oil casing, such as... Figure 1 As shown, it includes: S1. The sealing joint sample 1 was selected by simulating the actual working conditions of the gas-tight coupling and the oil casing in the well. S2. Obtain the stress and ultrasonic reflection coefficient of the sealing joint sample 1 under different torques, and calibrate the functional relationship between stress and ultrasonic reflection coefficient; S3. Obtain the stress of the sealing joint sample 1 under the same torque and different sealing performance, and determine the correspondence between stress and sealing performance; S4. Based on the functional relationship between stress and ultrasonic reflection coefficient, and the correspondence between stress and sealing performance, establish a numerical relationship model between ultrasonic reflection coefficient and sealing performance. S5. Obtain the ultrasonic reflection coefficient on the sealing end face of the casing and tubing entering the well, and output the corresponding sealing performance of the casing and tubing entering the well through a numerical relationship model.

[0020] By implementing the above-mentioned method for testing the sealing performance of casing and tubing, the sealing joint sample 1 simulates the actual working conditions of the gas seal and casing in the well, thus constructing a laboratory-scale working environment simulation. The stress magnitude of the sealing joint sample 1 under different torques is obtained, and the ultrasonic reflection coefficient corresponding to different torques is obtained using the pulse reflection method, thereby obtaining the functional relationship between stress and ultrasonic reflection coefficient. The principle of the pulse reflection method is that ultrasonic waves will be reflected at the interface of media with different acoustic impedances, such as the contact surface between the casing and tubing and the gas seal. When ultrasonic waves encounter these interfaces, they will be partially or completely reflected back. Therefore, by analyzing these reflected waves, specific internal properties of the workpiece or the stress magnitude between different media contact surfaces can be inferred. Furthermore, by measuring the stress magnitude of the sealing joint sample 1 with different sealing performances under the same torque, the relationship between stress and casing sealing performance can be obtained. By integrating the two relationships mentioned above, a numerical model relating ultrasonic reflection coefficient and sealing performance can be established. Using this numerical model, the sealing performance of the casing and tubing sealing face can be quickly assessed by ultrasonic testing of the tubing. This allows for dynamic monitoring and non-contact testing based on ultrasonic testing, improving the accuracy and reliability of sealing evaluation while significantly shortening the testing time. It also enables the timely detection of potential safety hazards and effectively prevents wellbore integrity problems caused by poor sealing between the gas seal and the casing and tubing, providing a more comprehensive and reliable basis for assessing the quality of the casing and tubing connection.

[0021] Furthermore, the method for obtaining the stress of the sealing joint sample 1 under different torques includes: Based on the mechanical analysis of the gas seal and casing under actual downhole working conditions, a stress calculation model is established at the sealing end face of the casing under standard torque. Select sealing joint sample 1 and apply torque to sealing joint sample 1; Starting from a preset initial torque, gradually increase the applied torque and record the torque value after each increase; Based on the recorded torque values, the stress corresponding to different torque values ​​is calculated sequentially using the established stress calculation model.

[0022] Through the implementation of the above-mentioned method for testing the sealing performance of oil casing and tubing, it is found that due to the complex downhole service environment, the stress on the oil casing and tubing has "multiple effects." The stress calculation model is based on the mechanical analysis and field survey of the gas seal and oil casing under actual downhole working conditions. The model can more accurately simulate and calculate the stress distribution under different torques when the gas seal and oil casing are sealed using the sealing joint sample 1, thus helping to more accurately evaluate the sealing performance of the oil casing and tubing in the future. Preferably, a standard torque (combined with...) is applied to the sealing joint sample 1 using the torque application module 2. Figure 2The torque can be gradually increased from zero, and the stress corresponding to different torque values ​​of the sealing joint sample 1 can be calculated sequentially until 100 sets of data are measured. By measuring more data points, the changes and trends in the data can be better captured, reducing the influence of random errors and improving the reliability and stability of the data, thereby helping to improve the detection accuracy of subsequent numerical relationship models.

[0023] Furthermore, based on the mechanical analysis of the gas-tight seal and casing under actual downhole operating conditions, a stress calculation model for the sealing end face of the casing under standard torque is established, including: Based on the mechanical analysis of the gas seal and the casing under actual downhole conditions, the standard model parameters of the casing and the stress parameters at the sealing end face of the casing and the casing under actual conditions are obtained. A three-dimensional model of the oil casing is established through numerical simulation, and material properties are defined in the established three-dimensional model. Determine the boundary conditions and loading method of the 3D model, and apply standard torque; Numerical simulation was run to calculate the stress and strain distribution at the sealing end face of the oil casing under standard torque; A stress calculation model for the sealing end face of the oil casing under standard torque is established based on the calculated stress and strain distribution.

[0024] By implementing the above-mentioned method for testing the sealing performance of the casing and tubing, a mechanical analysis of the gas seal and casing under actual downhole conditions is conducted, including stress conditions and contact states. Standard model parameters of the casing and tubing, such as dimensions and material properties, are obtained through experiments, theoretical calculations, or reference to relevant standards. Stress parameters at the sealing end face of the casing and tubing under actual conditions, such as torque and pressure, are determined. Numerical simulation techniques, such as finite element analysis (FEA), can be used to establish a three-dimensional model of the casing and tubing to provide more detailed and accurate simulation results, including stress, strain, and temperature distribution. To ensure the accuracy of the simulation, material properties defined in the three-dimensional model include elastic modulus, yield strength, and Poisson's ratio to accurately simulate the mechanical behavior of the material. For example, the same material as the casing and gas seal used under actual conditions is employed, and the thickness and surface roughness of the sealing joint sample 1 are consistent with those under actual conditions. Furthermore, based on the actual conditions, the boundary conditions of the three-dimensional model are determined, such as fixed constraints and contact constraints, and an appropriate loading method is selected, such as applying a standard torque to the sealing joint sample 1. Numerical simulation software, such as finite element analysis software, is used to simulate and calculate the established three-dimensional model. By running the numerical simulation, the stress and strain distribution of the oil casing sealing end face under standard torque is calculated, so that the established stress calculation model can be used to directly calculate the stress under different torques.

[0025] Furthermore, the method for obtaining the ultrasonic reflection coefficient of the sealing joint sample 1 under different torques includes: Ultrasonic waves were emitted onto the selected sealing joint sample 1; According to the pulse reflection method, the reflected wave signal reflected back from the sealing joint sample 1 after each increase in torque was recorded; The recorded reflected wave signals are processed and analyzed, and the ultrasonic reflection coefficients corresponding to different torque values ​​are calculated based on the amplitude ratio of the reflected wave signals to the preset reference signals.

[0026] By implementing the above-mentioned method for testing the sealing performance of oil casing, the sealing joint sample 1, the ultrasonic testing module 3, and the torque application module 2 (combined with) are installed in sequence. Figure 2 The ultrasonic testing module 3 is preferably an ultrasonic probe, which emits ultrasonic waves to the sealing joint sample 1 using an ultrasonic probe of a specific frequency and power. The emission angle and position can be selected according to the shape and size of the sealing joint sample 1 to ensure that the ultrasonic waves can fully irradiate the surface of the sealing joint. After the ultrasonic waves are emitted, an oscilloscope or other data acquisition device is used to record the reflected wave signals reflected back from the sealing joint sample 1. These reflected wave signals contain information about the surface characteristics and structure of the sealing end face in the sealing joint sample 1. While acquiring the reflected wave signals, the torque applied to the sealing joint sample 1 is gradually increased. The torque loading can be achieved using a torque loading device, and the increase in torque must be ensured to be uniform and controllable to achieve real-time ultrasonic testing of the sealing joint sample 1 during the torque increase process. Finally, the acquired reflected wave signals are processed and analyzed to extract information related to the ultrasonic reflection coefficient of the sealing joint sample 1, which may include signal filtering, amplification, digitization, and other processing steps. The preset reference signal can be a known standard signal or a reference signal obtained by measuring similar samples. The ultrasonic reflection coefficient corresponding to different torque values ​​is calculated by comparing the amplitude of the reflected wave signal with that of the preset reference signal. The analysis and comparison of reflected wave signals can be performed using methods such as spectral analysis and time-domain analysis. Finally, the reflected wave signals and corresponding ultrasonic reflection coefficient data under different torques are recorded and stored for subsequent calibration with the corresponding stress. The stress magnitude and ultrasonic reflection coefficient of the sealing joint sample 1 at different torque values ​​are measured sequentially until 100 sets of data are obtained.

[0027] Furthermore, the methods for obtaining the stress of the sealing joint sample 1 under the same torque but with different sealing performance include: Multiple sealing joint samples 1 with different sealing performance were selected and assigned to different test groups. The same torque was applied to the sealing joint specimen 1 of each test group, and the applied torque value was recorded; Based on the recorded torque values, the stress corresponding to each test group was calculated using the established stress calculation model.

[0028] Furthermore, methods for calibrating the relationship between stress and sealing performance include: Starting from the preset initial torque, gradually increase the torque applied to each test group, and ensure that the torque increase is the same for each test group each time; Record the torque value of each test group after each increase, and calculate the stress corresponding to each test group at different torque values ​​in turn using the established stress calculation model. Based on the recorded different torque values, the stress and sealing performance of each test group were analyzed and calibrated by comparing the stress at the same torque value.

[0029] By implementing the above-described method for testing the sealing performance of oil casing pipes, an initial torque value is determined at the beginning of the experiment, preferably starting from zero. This value is applied to the sealing joint of each test group. Then, the torque is gradually increased in the same increment, ensuring that the torque increase value is the same for each test group each time, so that the torque change is the same when comparing different test groups. By comparing the stress between test groups under the same torque value, and based on the stress corresponding to multiple different torque values ​​measured for each test group, more data points can be measured to better capture the data changes and trends of different sealing performances under the same torque, so as to accurately analyze the correspondence between stress and sealing performance. Preferably, a single test group can achieve 100 torque conditions by changing the applied torque, and the stress magnitude under each torque can be measured separately to reduce the influence of random errors, improve the reliability and stability of the data, and thus help improve the detection accuracy of the subsequent numerical relationship model.

[0030] Furthermore, the method for selecting multiple sealing joint samples 1 with different sealing performance includes: Based on the sealing performance characterized by a high degree of sealing, sample 1 of the sealing joint was selected, which simulated complete contact between the gas-tight buckle and the sealing end face of the oil casing. Based on the sealing performance characterized by moderate sealing degree, sample 1 of the sealing joint was selected, which simulated the presence of particles between the gas seal buckle and the sealing end face of the oil casing or the spacing was less than the preset distance. Based on the sealing performance characterized by low sealing degree, sample 1 of the sealing joint was selected, which simulated the presence of defects or a gap greater than the preset distance between the gas seal buckle and the sealing end face of the oil casing.

[0031] To characterize different sealing performances, three sets of sealing joint samples 1 with different sealing performances were selected using the above-described method for testing the sealing performance of oil casing and tubing: high sealing degree, medium sealing degree, and low sealing degree. High sealing degree corresponds to a completely sealed sealing end face of the sealing joint sample 1; medium sealing degree corresponds to the presence of small particles or tiny air gaps on the sealing end face of the sealing joint sample 1; and low sealing degree corresponds to the presence of impact defects or larger air gaps on the sealing end face of the sealing joint sample 1. By utilizing these three different sealing performance characteristics, and fully considering the presence of particles and defects on the sealing end face of the sealing joint sample 1, the stress under different sealing performances was calculated to calibrate the relationship between stress and sealing performance.

[0032] Furthermore, methods for obtaining the ultrasonic reflection coefficient on the sealing end face of the casing and tubing in the well, and outputting the corresponding sealing performance of the casing and tubing through a numerical relationship model, include: The sealing end face of the casing pipe in the well was tested using ultrasonic testing equipment, and the ultrasonic reflection coefficient on the sealing end face of the casing pipe in the well was recorded by pulse reflection method. The recorded ultrasonic reflection coefficients are input into the numerical relationship model, and the sealing performance of the well casing is output. If the output indicates a high degree of sealing performance, then it can be determined that there is no safety hazard in the gas tightness of the casing and tubing entering the well. If the output indicates a moderate sealing performance, it is judged that there is a general safety hazard in the gas tightness of the casing in the well. If the output indicates a low sealing performance, it is determined that there is an urgent safety hazard in the gas tightness of the casing and tubing entering the well.

[0033] By implementing the above-mentioned method for testing the sealing performance of casing and tubing, ultrasonic testing equipment is installed around the threaded sealing end face of the casing and tubing entering the well. The ultrasonic testing equipment is used to comprehensively test the sealing end face of the casing and tubing. During the testing process, the ultrasonic reflection coefficient on the sealing end face of the casing and tubing is accurately recorded using the pulse reflection method. The recorded ultrasonic reflection coefficient is then input into an established numerical relationship model. This model compares the input ultrasonic reflection coefficient with signal characteristics and an evaluation database, and outputs the corresponding sealing performance of the casing and tubing. If the output indicates a high degree of sealing performance, it means that the gas tightness of the casing and tubing is very reliable, with no safety hazards, and it can be safely used for oil or gas well production operations. If the output indicates a moderate degree of sealing performance, it indicates that the gas tightness of the casing and tubing has a certain degree of risk, and there may be general safety hazards. In this case, further evaluation and corresponding measures are needed to ensure the safe operation of the oil or gas well. If the output indicates a low sealing performance, it signifies a serious problem with the gas tightness of the casing and tubing in the well, posing an urgent safety hazard. Immediate emergency measures must be taken, including stopping the use of the casing and tubing and conducting a thorough inspection and repair to prevent potential accidents. Ultrasonic testing provides timely, accurate, and rapid information on the sealing performance of the casing and tubing in the well, offering strong support for the safe operation of oil or gas wells. Furthermore, real-time ultrasonic testing and sealing performance evaluation can effectively prevent potential safety hazards and ensure the smooth progress of oil and gas extraction operations.

[0034] Furthermore, the method for selecting the sealing joint sample 1 by simulating the actual working conditions of the gas-tight seal and the casing downhole includes: The parameters and conditions for the simulation test were determined based on the actual working conditions of the gas seal and the casing downhole. Based on the material properties of the gas-tight coupling and the oil casing, multiple sets of sealing joint samples were prepared using appropriate materials. Multiple sets of sealing joint samples 1 were simulated under determined parameters and conditions, and the parameter data of each set of sealing joint samples 1 were recorded during the simulation test. By comparing the parameter data of different groups of sealing joint samples 1, the sealing joint sample 1 that meets the preset requirements for sealing performance is selected.

[0035] The oil casing and tubing sealing performance testing method of this invention simulates the actual working conditions of the gas-tight joint and oil casing and tubing in the well in a laboratory setting. It obtains the stress magnitude of the sealing joint sample 1 under different torques and uses the pulse reflection method to obtain the ultrasonic reflection coefficient corresponding to different torques. By analyzing the relationship between the ultrasonic reflection coefficient and the corresponding stress, the functional relationship between stress and ultrasonic reflection coefficient is calibrated. Furthermore, by measuring the stress magnitude of the sealing joint sample 1 with different sealing performances under the same torque, the relationship between stress and sealing performance is calibrated. Finally, by combining the above two calibration relationships, a numerical relationship model relating sealing performance and ultrasonic reflection coefficient is established, thereby achieving the purpose of evaluating the sealing performance of oil casing and tubing by detecting the ultrasonic reflection coefficient. This invention, with its high precision, real-time dynamic monitoring, and non-contact testing method, effectively improves testing efficiency and promptly detects potential safety hazards, thereby effectively preventing wellbore integrity problems caused by poor sealing, reducing maintenance costs, ensuring the safe and stable operation of oil production, and saving enterprises significant human and material resources.

[0036] This invention also discloses a testing system that employs the above-mentioned method for testing the sealing performance of oil casing, comprising: Torque application module 2 is connected to the gas seal buckle and is used to apply torque to the gas seal buckle. The ultrasonic testing module 3 is in contact with the gas seal buckle and is used to emit ultrasonic waves to the sealing end face of the oil casing and receive the reflected wave signal reflected back from the sealing end face of the oil casing. The data analysis module interfaces with the ultrasonic testing module 3 to acquire the reflected wave signal received by the ultrasonic testing module 3 and to obtain the ultrasonic reflection coefficient based on the analysis of the reflected wave signal. The input / output module interfaces with the data analysis module to input the ultrasonic reflection coefficient and output the sealing performance of the oil casing through a numerical relationship model.

[0037] Through the implementation of the above-mentioned detection system, torque can be applied to the gas seal buckle using torque application module 2, and the gas seal buckle is inserted into the well and connected to the sealing end face of the casing. Ultrasonic detection module 3 emits ultrasonic waves to the sealing end face of the casing and receives the reflected wave signals. The data analysis module then analyzes and processes the reflected wave signals to obtain the ultrasonic reflection coefficient. The ultrasonic reflection coefficient is input into the numerical relationship model through the input / output module, and the sealing performance of the casing is calculated and output through the model. This achieves the goal of accurately determining the gas seal performance of the casing by detecting the ultrasonic reflection coefficient. The detection time for a single coupling is less than 60 seconds. Based on the advantages of ultrasonic detection, the accuracy and reliability of sealing evaluation can be optimized and improved, with a detection accuracy of 90%. This provides a more comprehensive and reliable basis for evaluating the quality of tubing connections, thereby enabling rapid and accurate detection and evaluation of the sealing performance of the casing. It also provides reliable technical support for oil and gas extraction and saves enterprises significant human and material resources.

[0038] It should be understood that the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them. Those skilled in the art can modify the technical solutions described in the above embodiments, or make equivalent substitutions for some of the technical features; and all such modifications and substitutions should fall within the protection scope of the appended claims of the present invention.

Claims

1. A method for testing the sealing performance of oil casing, characterized in that, The detection method includes: A sample of the sealing joint was selected by simulating the actual working conditions of the gas-tight seal and the casing in the well. The stress and ultrasonic reflection coefficient of the sealing joint sample under different torques were obtained, and the functional relationship between stress and ultrasonic reflection coefficient was calibrated. Obtain the stress of the sealing joint sample under the same torque but with different sealing performance, and calibrate the relationship between stress and sealing performance; Based on the functional relationship between stress and ultrasonic reflection coefficient, and the correspondence between stress and sealing performance, a numerical relationship model relating ultrasonic reflection coefficient and sealing performance is established. The ultrasonic reflection coefficient on the sealing end face of the casing and tubing entering the well is obtained, and the sealing performance of the casing and tubing entering the well is output through a numerical relationship model.

2. The method for testing the sealing performance of oil casing according to claim 1, characterized in that, The method for obtaining the stress of the sealing joint sample under different torques includes: Based on the mechanical analysis of the gas seal and casing under actual downhole working conditions, a stress calculation model is established at the sealing end face of the casing under standard torque. Select a sealing joint sample and apply torque to the sealing joint sample; Starting from a preset initial torque, gradually increase the applied torque and record the torque value after each increase; Based on the recorded torque values, the stress corresponding to different torque values ​​is calculated sequentially using the established stress calculation model.

3. The method for testing the sealing performance of oil casing according to claim 2, characterized in that, The method for establishing a stress calculation model at the sealing end face of the casing and tubing under standard torque, based on the mechanical analysis of the gas-tight seal and the tubing under actual downhole operating conditions, includes: Based on the mechanical analysis of the gas seal and the casing under actual downhole conditions, the standard model parameters of the casing and the stress parameters at the sealing end face of the casing and the casing under actual conditions are obtained. A three-dimensional model of the oil casing is established through numerical simulation, and material properties are defined in the established three-dimensional model. Determine the boundary conditions and loading method of the 3D model, and apply standard torque; Numerical simulations were run to calculate the stress and strain distribution at the sealing end face of the oil casing under standard torque. A stress calculation model for the sealing end face of the oil casing under standard torque is established based on the calculated stress and strain distribution.

4. The method for testing the sealing performance of oil casing according to claim 2, characterized in that, The method for obtaining the ultrasonic reflection coefficient of the sealing joint sample under different torques includes: Ultrasonic waves are emitted onto the selected sealing joint sample; According to the pulse reflection method, the reflected wave signal reflected back from the sealing joint sample after each increase in torque is recorded; The recorded reflected wave signals are processed and analyzed, and the ultrasonic reflection coefficients corresponding to different torque values ​​are calculated based on the amplitude ratio of the reflected wave signals to the preset reference signals.

5. The method for testing the sealing performance of oil casing according to any one of claims 2-4, characterized in that, The method for obtaining stress on the sealing joint sample under the same torque but with different sealing performance includes: Multiple sealing joint samples with different sealing performance were selected and assigned to different test groups. The same torque was applied to the sealing joint specimens of each test group, and the applied torque value was recorded. Based on the recorded torque values, the stress corresponding to each test group was calculated using the established stress calculation model.

6. The method for testing the sealing performance of oil casing according to claim 5, characterized in that, The method for determining the correspondence between calibrated stress and sealing performance includes: Starting from the preset initial torque, gradually increase the torque applied to each test group, and ensure that the torque increase is the same for each test group each time; Record the torque value of each test group after each increase, and calculate the stress corresponding to each test group at different torque values ​​in turn using the established stress calculation model. Based on the recorded different torque values, the stress and sealing performance of each test group were analyzed and calibrated by comparing the stress at the same torque value.

7. The method for testing the sealing performance of oil casing according to claim 5, characterized in that, The method for selecting multiple sealing joint samples with different sealing performance includes: Based on the sealing performance characterized by a high degree of sealing, a sealing joint sample was selected that simulated complete contact between the gas-tight buckle and the sealing end face of the oil casing. Based on the sealing performance characterized by moderate sealing degree, a sealing joint sample was selected that simulated the presence of particles between the gas seal buckle and the sealing end face of the oil casing or the spacing was less than the preset distance. Based on the sealing performance characterized by low sealing degree, sealing joint samples with defects or a gap greater than the preset distance between the simulated gas seal buckle and the sealing end face of the oil casing were selected.

8. The method for testing the sealing performance of oil casing according to claim 7, characterized in that, The method for obtaining the ultrasonic reflection coefficient on the sealing end face of the well casing and outputting the corresponding sealing performance of the well casing through a numerical relationship model includes: The sealing end face of the casing pipe entering the well was tested using ultrasonic testing equipment, and the ultrasonic reflection coefficient on the sealing end face of the casing pipe entering the well was recorded by pulse reflection method. The recorded ultrasonic reflection coefficients are input into the numerical relationship model, and the sealing performance of the well casing is output. If the output indicates a high degree of sealing performance, then it can be determined that there is no safety hazard in the gas tightness of the casing and tubing entering the well. If the output indicates a moderate sealing performance, it is judged that there is a general safety hazard in the gas tightness of the casing in the well. If the output indicates a low sealing performance, it is determined that there is an urgent safety hazard in the gas tightness of the casing and tubing entering the well.

9. The method for testing the sealing performance of oil casing according to claim 1, characterized in that, The method for selecting sealing joint samples by simulating the actual working conditions of the gas-tight seal and casing in the well includes: The parameters and conditions for the simulation test were determined based on the actual working conditions of the gas seal and the casing downhole. Based on the material properties of the gas-tight seal and the oil casing, multiple sets of sealing joint samples were prepared by selecting appropriate materials. Multiple groups of sealing joint samples were simulated under determined parameters and conditions, and the parameter data of each group of sealing joint samples were recorded during the simulation test. By comparing the parameter data of different groups of sealing joint samples, the sealing joint sample that meets the preset sealing performance requirements is selected.

10. A testing system employing the oil casing sealing performance testing method according to any one of claims 1-9, the testing system comprising: A torque application module, connected to the gas seal buckle, is used to apply torque to the gas seal buckle; An ultrasonic testing module, in contact with the gas-tight buckle, is used to emit ultrasonic waves to the sealing end face of the oil casing and to receive the reflected wave signal reflected back from the sealing end face of the oil casing. The data analysis module interfaces with the ultrasonic detection module to acquire the reflected wave signal received by the ultrasonic detection module and to obtain the ultrasonic reflection coefficient based on the reflected wave signal analysis. The input / output module interfaces with the data analysis module to input the ultrasonic reflection coefficient and output the sealing performance of the oil casing through a numerical relationship model.

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