Overview of Pressure-Resistant Sealing and Debugging Technology: A Key Step for Ensuring Pipeline Safety Operation When the oil and gas pipelines are not in operation, the pressure-sealing technology is quietly safeguarding the safety of the country's energy arteries. In the pipeline transportation industry, the pressure-sealing technology has become an indispensable technical means for ensuring the safe operation of oil and gas pipelines. This technology enables the sealing of sections with defects or those requiring renovation without interrupting the pipeline's flow, significantly reducing the production halt and economic losses caused by traditional operation methods. As China's oil and gas pipelines gradually enter the aging stage - with the proportion of in-service pipelines that have been in operation for more than 10 years reaching approximately 60%, the importance of pressure-sealing technology is becoming increasingly evident. 01 Technical Principles and Classification The pressure-sealing technology is a technical means that enables the installation of sealing devices on the pipeline using specialized equipment, thereby achieving the purpose of cutting off the flow of the medium inside the pipeline without interrupting the pipeline's normal operation. From a theoretical perspective, this technology is mainly based on the interdisciplinary integration of fluid mechanics, material mechanics and sealing technology. By establishing temporary sealing points inside or outside the pipeline, it enables the isolation and maintenance of the pipeline. According to the differences in the sealing principle, the pressure-bearing sealing technology can be divided into several main types. Mechanical plugging is the most common form. It involves deploying a plugging head inside the pipeline through mechanical means, using the elastic deformation of the sealing elements to achieve a close fit with the pipe wall, thereby blocking the flow of the medium. The capsule-type sealing method relies on the expansion pressure of the inflatable or liquid-filled capsule bag to ensure that the outer surface of the capsule bag closely contacts the inner wall of the pipeline, thereby forming a seal. Another classification method is based on the location of the blocking point, and can be divided into internal pipe blocking and external pipe blocking. The internal pipe blocking technology deploys the blocking device inside the pipeline, such as the internal low-pressure intelligent blocking device; While external pipe sealing involves creating an opening outside the pipe and using sealing equipment to achieve the interception of the medium. According to the pipeline operating conditions, pressure-bearing plugging can be further divided into low-pressure plugging and high-pressure plugging. For different pressure levels, the design concepts and technical requirements of the plugging equipment vary significantly. Low-pressure sealing generally employs mechanical sealing devices, which have relatively simple structures; while high-pressure sealing requires more complex structural designs and higher-performance sealing materials. 02 Debugging Process and Technical Key Points The commissioning of pressure-sealing operations is a complex engineering task that requires strict adherence to the procedures to ensure every step is precise and error-free. The complete commissioning process of pressure sealing includes four main stages: pre-preparation, equipment debugging, sealing execution, and status monitoring. During the preparatory stage, a comprehensive data collection of the operation pipeline is required, including parameters such as pipe diameter, wall thickness, medium pressure, temperature and chemical properties. At the same time, an appropriate sealing process and equipment should be selected based on these parameters. Equipment debugging is the key to ensuring the success of the sealing operation. For mechanical sealing equipment, the focus of debugging should be on the feed accuracy of the cutter head, the dynamic balance performance, and the installation quality of the sealing components. The debugging of the hydraulic system needs to ensure that each actuator operates accurately and the pressure control is precise. Taking a typical pressure-bearing hole opening and sealing operation as an example, its specific process includes: Determine the construction site and excavate the operation pit Remove the anti-corrosion coating of the pipeline and weld a tee at the designated position. Perform non-destructive testing on the weld seams to ensure quality. Install the hydraulic gate valve and the hole opener. During the hole opening operation, special attention must be paid to pressure balance - by setting a venting port near the sealing opening, the internal and external pressures of the hole opening tool can be balanced to ensure the safety of the operation. After the hole is drilled, the installation of the bypass pipeline and the pressure test are also required. Usually, water pressure testing is conducted at 6 MPa and maintained for 24 hours to verify the sealing performance. 03 Progress of Intelligent Debugging Technology With the advancement of technology, the debugging methods for pressure-sealing technologies have also been constantly innovated. Intelligence has become the development trend in this field. The in-line low-pressure intelligent sealing technology is an innovative solution that has emerged in recent years. This sealing device integrates two functional units: sealing and traction. Compared with traditional high-pressure intelligent sealing devices, it has the advantages of fewer functional units, simpler structure, and lower processing costs. Meanwhile, compared with the traditional low-pressure sealing technology, it has the advantages of higher sealing pressure and more reliable and stable sealing performance. The electrically controlled integrated blocking device independently developed by Bohai Drilling represents the highest level in this field in China. This tool integrates the functions of electrically controlled blocking and electrically controlled retrieval, enabling simultaneous precise blocking of the downhole pipe string and efficient setting. It possesses outstanding performance in withstanding high temperatures (180 degrees Celsius) and high pressures (equivalent to 700 atmospheres), providing a more reliable "backing" for well repair operations. The application of the electronic control blocker has made the traditional and complex tubing string lifting operation simple and efficient - operators only need to press the electronic control button to precisely complete all operations such as injection and blocking, fishing, and retrieval. The data shows that after using this tool, the average construction period of well repair operations was shortened by 20%, and the success rate of a single operation increased to over 98%. Another major breakthrough in intelligent debugging technology is the integration of remote monitoring and automatic control systems. By installing sensors on the sealing equipment, real-time collection of parameters such as pressure, temperature, and displacement is achieved, and a mathematical model is established in combination with control theory. The researchers conducted simulation analysis using the MATLAB software, ensuring that the dynamic characteristic indicators of the control system met the design requirements. 04 Common Questions and Solutions