After the sealing operation, the real test: A comprehensive inspection and analysis guide for the entire process of pressure-sealing operationsIn the veins of modern industry - the extensive network of oil and gas, chemical, and utility pipelines buried beneath the ground - the pressure sealing technology is hailed as the "heart surgery" of uninterrupted pipeline operations. It enables maintenance, renovation, or emergency rescue operations to be carried out under the continuous operating pressure of the pipelines, avoiding the shutdown of the entire system and the attendant huge economic losses and safety risks. However, when the last dose of sealant is injected and the last bolt is tightened, and the tense atmosphere at the site dissipates, a more rigorous and meticulous task - the post-operation inspection and analysis - has just begun - this is not only the final judgment on the safety of this operation, but also the cornerstone for accumulating industry wisdom and promoting technological progress. 1. Why are inspections and analyses the lifeline of the sealing operation? The inspection after the completion of the assignment is not merely a "quick glance", but rather a systematic verification process. It directly addresses three core questions: 1. Is this sealing operation absolutely safe and reliable? This is the most fundamental requirement, ensuring that the sealing point will not leak or fail during the long-term operation in the future. 2. Was the entire operation process standardized and optimal? Through review and analysis, examine every step from preparation to execution, identify potential risks and areas for improvement. 3. What knowledge and data have been accumulated for similar future tasks? Every practical operation is a valuable experiment, and the data obtained can optimize the technology, train personnel, and improve standards. Ignoring the inspection and analysis is like completing a precise surgery but never conducting a post-operation review, leaving potential risks for the future. According to the newly released "AQ 3060-2025 Safety Management Specifications for Pressure-Enclosed Sealing and Pressure-Enclosed Opening Operations", the acceptance and evaluation after the operation have become mandatory safety management steps. Meanwhile, the "Technical Specifications for Pressure-Enclosed Sealing of Pressure-Enclosed Equipment" at the national level is also being revised, aiming to unify and strengthen the standards for the entire process from construction preparation to completion acceptance. II. Four-dimensional Inspection and Analysis: Establishing a Comprehensive Evaluation System A comprehensive post-sealing assessment should be carried out from the following four aspects in a three-dimensional manner: Dimension 1: Visual Physical Inspection - The "Medical Report" of the Sealing Body This is the most fundamental and straightforward inspection. The technicians need to conduct a thorough examination of all external components such as the sealing fixtures, the injection valve, and the connecting bolts. · Fit between fixture and pipeline: Check whether the fixture is tightly attached to the outer wall of the pipeline, and look for any gaps caused by the elliptical shape of the pipeline or improper installation. · Sealing of injection holes and exhaust holes: Ensure that all the blocking screws for the injection holes and exhaust holes are tightly fastened and sealed. · Appearance and Corrosion Prevention: Check for any new damages or rust in the clamps and surrounding areas, and ensure that the anti-corrosion coating remains intact. A successful drill demonstrated that after the pressure holding test, using soapy water to conduct a detailed leak detection at all connection points is an effective method for verifying the initial seal. Dimension 2: Performance Verification Test - "Pressure Test" for Sealed System This is the core for evaluating the quality of the internal sealing. Depending on the pipeline conditions, two main types of tests are conducted: · Tightness test (soap water inspection): On the system that has been sealed, apply a certain test pressure (usually higher than the operating pressure), and then apply soap water or a special leak detection solution to all possible leakage points (such as welds, bolts, injection holes). Any tiny bubbles produced indicate failure. This method is simple and intuitive and is often used for the initial verification of medium and low-pressure systems. · Strength (Pressure) Test: For high-pressure or critical pipelines, more rigorous pressure tests are required. The section of the pipeline that is sealed and isolated will be pressurized to the specified value (such as 1.5 times the design pressure), and the pressure will be maintained for a sufficient period of time (such as 30 minutes to 1 hour). The pressure gauge will be observed to see if there is any continuous drop in pressure. In a drill conducted by Beijing Pipeline Company, the pressure was successfully raised from 0.2 MPa to 10 MPa and maintained for 1 hour without any leakage, proving the reliability of the sealing strength. Dimension Three: Data Monitoring and Analysis - "Remote Monitoring" for System Operation The long-term health after the blockage depends on continuous monitoring. This includes: · Remote monitoring of pressure and temperature: Install pressure and temperature sensors at both the upstream and downstream of the sealing point to monitor real-time data changes. Abnormal pressure fluctuations may indicate new leaks or failure of the sealing. · Medium composition and environmental monitoring: For flammable, explosive or toxic media, gas detectors are installed around the sealing points to continuously monitor whether there is any trace emission of the medium in the environment. The case shows that when investigating the leakage of aviation fuel pipelines, by monitoring the pressure changes of nitrogen gas inside the pipeline, the leakage section was successfully identified. Dimension Four: Material and Process Review - "In-depth Analysis" of Technological Application This is the crucial step in converting experience into knowledge. It focuses on the "materials" used and the "methods" adopted in the work. · Performance verification of sealant: The sealant is the "meat" that seals the area. It is necessary to conduct professional evaluations on its curing time, final hardness, compressive strength, bonding strength with the pipe wall, and resistance to medium corrosion. For instance, does the curing time match the on-site temperature and humidity? Can the final strength withstand the pressure fluctuations of the pipeline? These data provide a direct basis for the next material selection. · Process applicability analysis: Review whether the selected sealing techniques (such as fixture injection, patching board method, B-type sleeve welding, etc.) are the most suitable for the specific leakage form, medium, and pressure at that time.