High-pressure pipeline "heart surgery": Unveiling the installation and reliability of "zero leakage" sealing technologyFacing the high-pressure (over 10 megapascals) and flammable/explosive oil and gas inside the pipeline, a professional team was able to precisely complete the sealing installation like performing a "heart bypass surgery", ensuring that the medium did not leak at all. On long-distance high-pressure oil and gas pipelines, a successful operation of pressure-bearing hole opening and sealing is as technically complex and safety-demanding as a surgical procedure. The core objective of this technology is to physically isolate a specific section of the pipeline without interrupting the continuous transportation or reducing the pressure. It achieves this through a set of precise equipment and rigorous procedures, providing the necessary conditions for subsequent maintenance, renovation or replacement. This is not only a technical challenge, but also a test of the ultimate reliability of the equipment, the professionalism of the personnel, and the meticulousness of management. 01 Technical Standards and Core Challenges The implementation of any high-pressure pipeline sealing operation must be based on strict technical standards. The updated national standard "Technical Specifications for Pressure Sealing of Steel Pipelines" in 2023 is the fundamental guideline in this field. It specifies in detail the technical requirements for opening holes and sealing operations, and is applicable to various sealing methods including plug type, folding type, cylindrical type, and bag type. The newly revised petroleum and natural gas industry standard "Technical Specifications for Sealing of Steel Pipelines - Part 1: Plug-Type and Tube-Type Sealing" in 2024 further refined the operational norms of mainstream sealing technologies, marking the maturity of the domestic technical system. The core challenge in sealing high-pressure pipelines lies in the harmonious integration of high risks and high requirements. The entire operation is classified as a "super-level hot work operation", and the oil and gas media inside the pipeline are highly flammable and explosive. Any minor mistake could lead to catastrophic consequences. The primary goal is to achieve absolute sealing during the sealing process, which is the "zero leakage" that the industry strives for. This requires that the sealing equipment itself must be highly reliable, and the sealing structure must be able to withstand the tests of pipeline pressure, medium corrosion and temperature changes for a long time. At the same time, modern long-distance oil and gas pipelines generally adopt high-strength pipeline steel, and its hardness poses extremely high requirements for the performance of the opening tool and the stability of the opening process. 02 Innovation of Key Equipment and Breakthrough in Reliability To truly achieve safe sealing, continuous innovation in technical equipment is indispensable. In recent years, domestic high-end sealing equipment has made significant breakthroughs in key technologies. Firstly, the stability and reliability of the hole-making operation. The new hole-making machine has added a redundant high-pressure balancing system. Even if one system fails unexpectedly, it can immediately switch to the backup system, fundamentally avoiding serious accidents such as "tool jamming" caused by balance failure, and ensuring the success rate of the hole-making operation. Meanwhile, to handle the high-strength pipeline steel, the hole-cutting tool adopts military-grade welding technology and specially designed hard alloy teeth, ensuring smooth and efficient cutting. The next major innovation is in the fundamental aspect of the sealing technology. In the core sealing component of the sealing head, the traditional lip seal has been replaced by a multi-line sealed rubber cup. This design, optimized through fluid dynamics simulation, can better adapt to pressure fluctuations in the pipeline and maintain tightness under both high and low pressure conditions. More importantly, to prevent the rubber gasket from being scratched by the metal debris produced by the holes, the new sealing head integrates a dedicated debris sweeping device, which can completely remove the iron filings and eliminate a major leakage hazard. Finally, there is a revolutionary advancement in the structure of the sealing components. The traditional "external clamp-type" sealing positioning structure (relying on locking pins and locking rings) has been proven to be a potential leakage point during long-term operation. The new "in-line" leak-free pipe fittings completely eliminate these external components. They achieve the expansion and locking of the card plate through an internal transmission mechanism, structurally eliminating the possibility of leakage caused by the aging of the sealing ring or the failure of the lock pin. Practice has proven that this structure has achieved over 20 years of leak-free operation records. 03 Scientific and rigorous operation procedures A truly successful installation of a seal is achieved through the strict implementation of a scientific process. The entire procedure is interdependent and any oversight is strictly prohibited. Pre-evaluation and planning This is the foundation of the operation. It is necessary to accurately calculate the operating pressure of the pipeline, the properties of the medium, and the parameters of the pipe material, and strictly follow national standards such as GB/T 28055 to formulate the operation plan. For ultra-high pressure pipelines, even the "shutdown combined with plugging" process may be adopted. This process decomposes a single ultra-high pressure operation into multiple pressure-controlled plugging operations to mitigate risks. Pipe fitting welding and equipment installation On the confirmed pipeline section, the first step is to weld the specially designed blocking three-way valves as the "interface" for all subsequent operations. The welding quality must reach the highest standard. Subsequently, the connection frame containing the clamp valve is installed to construct a sealed pressure chamber isolated from the outside world, which is the prerequisite for pressure-laden operations. Pressure-holding opening Install the hole-making machine on the frame and connect it to the pipeline interior through the clamp valve. Under the drive of hydraulic or pneumatic power, the hole-making tool cuts a hole on the pipeline wall that is exactly the same size as the sealing head. The cut-off pipe wall material block is completely removed. This entire process is carried out under the monitoring of the pressure balance system. Blocking and Bypassing After the hole is drilled, replace the plug and insert the plug head into the pipeline. Operate the plug (such as a rubber cup) to expand and closely adhere to the inner wall of the pipeline, thereby blocking the flow of the medium in this pipe section. At the same time, temporary bypass pipelines will be set up to connect the two ends of the blocked section, ensuring that the transportation function of the entire pipeline system is not interrupted. Stopping and Restoring After confirming that the sealing is tight, the "lower plug" operation is carried out, which means installing a permanent blocking device.