How long does it take to repair a high-pressure pipeline with a pressurized opening? In-depth analysis of construction duration and influencing factors In modern industrial pipeline operation and maintenance, the pressure-bearing opening technology has become an indispensable core process. When a high-pressure pipeline needs to be renovated, repaired, or branched out, one of the most concerned issues for the owner and the construction party is: How long does it take to repair the pressure-bearing opening of the high-pressure pipeline? The answer to this question is not a simple number. Based on a large number of engineering cases accumulated from practice, the duration of pressure-bearing hole opening operations can range from several minutes to several hours, or even several days. The specific duration is significantly influenced by multiple factors such as pipeline parameters, construction environment, process complexity, and preparatory work. This article will start from real engineering cases, systematically analyze the composition of the time for pressure-bearing hole opening operations, identify the key variables affecting the construction period, and provide you with a scientific time estimation framework. I. Analyzing the Time Span of Pressure-Resistant Hole Opening from Real Cases Before answering the question "How long does it take?", let's first look at several real engineering cases from different industries and scenarios to get a clear understanding of the time differences in pressure-bearing hole opening operations. Case One: Efficient Work - Completing Well Opening Without Water Interruption in 40 Minutes During a technical renovation of a water supply system, the technicians adopted the process of opening holes while keeping the water supply uninterrupted and under pressure. Based on thorough preparations and simulation exercises, they completed the entire opening operation in just 40 minutes. This case demonstrates that under conditions of smaller pipe diameters and relatively simple working conditions, pressure-assisted hole opening can achieve extremely high operational efficiency. Case 2: Moderate Pace Progression - Completing 29 tasks in 3.5 hours In 2025, the Mianyang Gas Group successfully implemented the pressure-protected non-stop pipeline replacement sealing and opening hole technology. The entire construction process was completed in just 3.5 hours, covering 29 operations including pipeline cleaning, opening hole sealing, and welding restoration. This achieved a new model of "gas supply while construction". This case demonstrates that under conditions of highly standardized processes and close teamwork, complex operations can also be completed efficiently. Case 3: Routine task - Complete single-point hole drilling within 6-8 hours Based on industry experience data, under typical working conditions, the time required for single-point pressure-bearing hole opening and plugging operations is usually around 6 to 8 hours, which is more than 50% shorter than traditional construction methods. For instance, a DN2400 large-diameter gas pipeline with pressure-bearing hole opening operation was successfully completed after 8 hours of continuous and uninterrupted work; the pressure-bearing hole opening operation carried out by the Northwest Oilfield in a high-pressure and high-sulfur environment took nearly 6 hours to complete. Case 4: Challenge of Large Diameter - The 4.5-hour Opening Process In the valve chamber pressure guiding pipe renovation project of the western section of the second line, the construction team carried out pressure-sealing operations on the DN400 pipe. The drilling machine moved at a constant speed of 12 rotations per minute. The entire drilling process took nearly 5 hours. It is necessary to distinguish between the "drilling process" and the "overall operation time" - the drilling process is merely one part of the entire maintenance work, and the overall duration is usually longer. Case Five: Engineering-level Cycle - System Renovation Taking More Than 30 Days When pressure-bearing hole opening is part of a large-scale pipeline renovation project, the construction period is often calculated in terms of "days" or even "months". For instance, in the construction plan for pressure-bearing hole opening and sealing of a certain high-pressure gas pipeline, the specified construction period is 30 days. In a complex pipeline renovation project of Zhengzhou Huaren Gas, the team remained on site for 30 consecutive days to complete six sealing and six blocking operations, during which 26,000 residents' gas supply was not affected. In the main line expansion and renovation project of the West-to-East Gas Pipeline, the entire project has a construction period of only two months. The pipeline maintenance and repair company needs to complete a series of tasks such as drawing design, mechanical processing, simulation experiments, and on-site hole opening within this time limit. These cases clearly demonstrate that the duration of pressure-holding perforation is not a fixed value but rather a range. From the single-point rapid perforation that takes only a few minutes, to the standard operation that lasts several hours, and to the systematic renovation project that takes several days, the time span for pressure-holding perforation is extremely wide. So, what factors determine this duration? II. Key Factors Affecting the Time for Pressure-Resistant Hole Opening To accurately estimate the time required for pressure-bearing opening operations, it is necessary to first understand the key variables that affect the duration of the construction. The following six factors are the crucial determinants of the project's completion time: Pipeline parameters: pipe diameter, wall thickness and pressure rating The basic parameters of the pipeline are the most direct factors influencing the opening time. · Pipe diameter: The larger the pipe diameter, the longer the circumference of the cut pipe wall, and the natural opening time will be longer. Generally, opening a hole in a medium-sized pipe takes about 1 hour, while for a large-sized pipe, it requires 6-8 hours. The opening of an ultra-large diameter pipe with DN2400 requires continuous 8-hour non-stop operation. · Wall thickness and steel grade: The thicker the pipe wall and the higher the steel strength, the greater the cutting difficulty and the longer the required time. The main pipeline of the West-to-East Gas Transmission project has a diameter of 1016 millimeters, uses X70 steel, and has a wall thickness of 26.2 millimeters. When a 900-millimeter circular hole is drilled under a pressure of 6.0 megapascals, it is a highly challenging operation involving large diameter, thick wall, and large opening. This poses a significant challenge to the opening time. · Pressure level: The pressure-bearing opening of high-pressure pipelines requires a more cautious operation rhythm. When operating in a high-pressure and high-sulfur environment, the special alloy drill bit of Northwest Oilfield cuts into the pipe wall at a slow speed of 10 revolutions per minute, in order to ensure safety. 2. The degree of thoroughness in the preparatory work A successful pressure-bearing hole-opening repair operation is 70% dependent on thorough pre-work preparations. The pre-work time usually accounts for more than 30% of the total time, including: · On-site investigation and data collection: Confirm the material, diameter, wall thickness, medium, pressure, temperature and other parameters of the pipeline, and assess the working environment. The professional team can complete the preliminary analysis of pipeline parameters within 2 hours. · Scheme design and equipment selection: Select appropriate-sized hole-making machines, valves and connecting components based on pipeline parameters, and formulate an emergency plan. · Work Permit and Approval: Obtain tickets for operations such as hot work, confined space entry, and high-altitude work.