Innovative method for hydrostatic test of long-distance pipeline and related equipment

Abstract

The invention provides a long-distance pipeline hydrostatic test innovation method and related equipment, and the method comprises the steps: carrying out the pressure test segmentation of a long-distance pipeline based on the related parameters of the long-distance pipeline, so as to obtain a first-stage pipe section; according to a water filling control condition, the pipe section of the stage is filled with water, so that a pipe section of a second stage is obtained; continuously injecting water into the pipe section in the second stage to increase the pressure of the pipe section in the second stage to thermodynamic equilibrium pressure to obtain a pipe section in a third stage; boosting the pipe section of the third stage to obtain a first detection result and a pipe section of a fourth stage; in response to the fact that the first detection result is qualified, the air existing amount in the pipe section is calculated, and a second detection result and the pipe section of the fifth stage are obtained; performing a sealing test on the pipe section in response to the fact that the second detection result is qualified so as to obtain a third detection result; and if the third detection result is qualified, determining that the quality of the long-distance pipeline is qualified. Through the method, the accuracy of quality detection of the long-distance pipeline can be improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the fields of oil and gas storage and transportation engineering technology and long-distance pipeline engineering construction, and particularly relates to a long-distance pipeline water pressure test innovative method and related equipment. BACKGROUND

[0002] In today's energy transportation field, long-distance pipelines, as an efficient and stable transportation method, bear the heavy responsibility of cross-regional allocation of important energy such as oil, refined oil, natural gas, hydrogen, ore slurry, and water. The safety and reliability of its operation are directly related to the stability of energy supply and the safety of the surrounding environment and people's lives and property.

[0003] Water pressure test, as a key link in the construction of long-distance pipelines to test the strength, sealing performance and overall quality of the pipeline, is of great significance. However, the main technical provisions of the pipeline pressure test in the current standard (such as the length of the pressure test section, the final pressure test qualification standard, etc.) are determined based on years of construction experience, and some provisions are questionable, and the pressure test technology also lacks scientific and technical support.

[0004] The paper "Water Pressure Test Technology of Foreign Pipeline Engineering" records a water pressure test technology. However, the detection accuracy of this technology is not enough, far from meeting the quality detection accuracy requirements of long-distance pipelines. SUMMARY

[0005] Therefore, the present application provides a long-distance pipeline water pressure test innovative method and related equipment to solve or partially solve the above problems.

[0006] In a first aspect, the present application provides a long-distance pipeline water pressure test innovative method, comprising:

[0007] Segmenting the long-distance pipeline for pressure test based on related parameters of the long-distance pipeline to obtain a first-stage pipe section, the related parameters including a height difference of the long-distance pipeline;

[0008] Filling water in the first-stage pipe section according to a water filling control condition to obtain a second-stage pipe section, the water filling control condition being determined based on a water injection rate and back pressure in the water filling process;

[0009] Continuously injecting water in the second-stage pipe section to raise the pressure of the second-stage pipe section to a thermal equilibrium pressure to obtain a third-stage pipe section;

[0010] Performing pressure raising processing on the third-stage pipe section to obtain a first detection result and a fourth-stage pipe section;

[0011] In response to the first detection result being qualified, performing an air existence amount test on the fourth-stage pipe section to obtain a second detection result and a fifth-stage pipe section;

[0012] In response to the second test result being qualified, a sealing test is performed on the pipe section of the fifth stage to obtain the third test result;

[0013] In response to the third test result being qualified, the quality of the long-distance pipeline is determined to be qualified, and the hydrostatic test of the long-distance pipeline is completed.

[0014] A second aspect of this application provides an innovative method for hydrostatic testing of long-distance pipelines, comprising:

[0015] The pressure testing segmentation module is configured to perform pressure testing and segmentation of the long-distance pipeline based on relevant parameters of the long-distance pipeline to obtain a first-stage pipeline segment, wherein the relevant parameters include the elevation difference of the long-distance pipeline;

[0016] A water filling module is configured to fill the pipe section of the first stage with water according to water filling control conditions to obtain the pipe section of the second stage, wherein the water filling control conditions are determined based on the water injection rate and back pressure during the water filling process.

[0017] The first booster module is configured to continuously inject water into the second stage pipe section to increase the pressure of the second stage pipe section to the thermal equilibrium pressure, thereby obtaining the third stage pipe section.

[0018] The second boost module is configured to boost the pressure of the pipe segment in the third stage to obtain the first detection result and the pipe segment in the fourth stage.

[0019] An air presence calculation module is configured to calculate the air presence in the pipe section of the fourth stage in response to the first detection result being qualified, thereby obtaining the second detection result and the pipe section of the fifth stage.

[0020] A sealing test module is configured to perform a sealing test on the pipe section of the fifth stage in response to the second test result being qualified, so as to obtain a third test result;

[0021] The quality assessment module is configured to determine the quality of the long-distance pipeline is qualified in response to the third test result being qualified, so as to complete the hydrostatic test of the long-distance pipeline.

[0022] In a third aspect, this application provides an electronic device including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor, when executing the computer program, performs the steps of the method described in the first aspect.

[0023] In a fourth aspect, this application provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the steps of the method described in the first aspect.

[0024] This application provides an innovative method for hydrostatic testing of long-distance pipelines, comprising: dividing the long-distance pipeline into test sections based on relevant parameters to obtain a first-stage pipe section; filling the pipe section with water according to water filling control conditions to obtain a second-stage pipe section; continuously injecting water into the second-stage pipe section to raise its pressure to the thermal equilibrium pressure to obtain a third-stage pipe section; pressurizing the third-stage pipe section to obtain a first test result and a fourth-stage pipe section; calculating the air content within the pipe section in response to the first test result being qualified to obtain a second test result and a fifth-stage pipe section; conducting a sealing test on the pipe section in response to the second test result being qualified to obtain a third test result; and determining the quality of the long-distance pipeline to be qualified in response to the third test result being qualified. This method can improve the accuracy of quality testing for long-distance pipelines. Attached Figure Description

[0025] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments of this application will be briefly introduced below. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort, and these are all within the protection scope of this application.

[0026] Figure 1 A flowchart illustrating an exemplary innovative method 100 for hydrostatic testing of long-distance pipelines according to an embodiment of this application is shown.

[0027] Figure 2 A cross-sectional view of an exemplary pressure testing pipe section according to an embodiment of this application is shown.

[0028] Figure 3 A flowchart illustrating an exemplary hydrostatic test procedure according to an embodiment of this application is shown. Detailed Implementation

[0029] The technical solution of this application will be clearly and completely described below with reference to the embodiments of this application. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0030] It should be particularly noted that similar substitutions and modifications made to this application are obvious to those skilled in the art, and they are all considered to be included in this application. Those skilled in the art can obviously make modifications or appropriate alterations and combinations to the methods and applications described herein without departing from the content, spirit, and scope of this application to implement and apply the technology of this application. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments.

[0031] As mentioned above, hydrostatic testing is a crucial step in the construction of long-distance pipelines to verify pipeline strength, sealing performance, and overall quality, and is of paramount importance. However, the main technical provisions of pipeline pressure testing in current standards (such as the length of the test section and the final test qualification criteria) are based on years of construction experience, and some provisions are open to discussion. Furthermore, the pressure testing technology lacks scientific and technological support.

[0032] Judging from the current situation of pipeline construction, a newly built gas pipeline has already experienced an explosion due to weld defects during operation. This is a major safety accident that escalated from a quality problem. This suggests that the hydrostatic test has not yet played a final inspection and control role in the safety testing of this pipeline, reflecting some deficiencies in the pressure testing standards and techniques.

[0033] Existing construction technologies and standards for hydrostatic testing of long-distance pipelines have gradually revealed numerous problems when dealing with complex geological conditions, different pipe diameters and material combinations, and the need for efficient and accurate monitoring. Current standards for passing pressure tests do not consider or differentiate factors such as the amount of air present in the test section, changes in ambient temperature, and the impact of temperature changes on pressure. This is unscientific and unreasonable, and could pose a hidden danger to the long-term safe operation of the pipeline.

[0034] The hydrostatic test is a crucial final comprehensive quality inspection procedure in the construction of long-distance pipelines. It is a key link in verifying the quality of pipeline construction and ensuring operational safety. It is an effective way to directly verify whether the pipeline strength meets the design requirements. It is a comprehensive inspection of the quality of the entire pipeline system, including the quality of pipe materials, welding quality, and pipe fitting connection quality. It is a quality verification of the integrity of the pipeline system.

[0035] Currently, traditional hydrostatic testing processes have many shortcomings. The hydrostatic testing standards for long-distance pipelines are all conducted in accordance with the relevant clauses of the "Code for Construction and Acceptance of Oil and Gas Pipeline Engineering" GB50369-2014, and its main technical clauses for pressure testing are shown in Table 1.

[0036] Table 1: Requirements and Acceptance Standards for Water Pressure Tests in the Specifications

[0037]

[0038] As can be seen from Table 1, the pass standard for the strength test in the specification is no deformation and no leakage; the pass standard for the tightness test in the specification is a pressure drop of no more than 1% of the test pressure value and no more than 0.1 MPa.

[0039] In strength and sealing tests, the acceptance criteria for these tests, taking into account factors such as pipe length, diameter, the amount of water and air present in the test section, ambient temperature changes, and the impact of temperature changes on pressure, can affect the accuracy of determining the cause of pressure drop. For example, it may determine whether the pressure drop is due to pipe leakage or the influence of air within the pipe. Current test acceptance criteria, as shown in Table 1, are based on engineering experience and are neither scientific nor reasonable. Furthermore, traditional pipe leak detection methods have limited accuracy and struggle to detect minor leaks in a timely manner. Therefore, traditional pipe leak detection methods are not suitable as the final checkpoint for quality inspection of long-distance pipeline construction, potentially posing a safety hazard for the long-term safe operation of the pipeline.

[0040] In addition, during hydrostatic testing, the pressure change within the pipeline is directly related to the volume change of the water filling the pipeline. This volume change may be caused by pipeline leakage, temperature changes, the influence of air inside the test pipeline, or the combined effect of the aforementioned factors. Therefore, the factors influencing pressure drop changes within the pipeline are complex, and it is inaccurate to determine whether a pipeline has a leakage problem solely based on changes in pressure drop.

[0041] The above are the problems with the existing standards and requirements for hydrostatic testing. The existing standards for segmented pressure testing of long-distance pipelines also have problems.

[0042] Clause 14.3.2 of GB50369-2014 stipulates that "the length of the pipe section for the segmented hydrostatic test should not exceed 35 kilometers." However, this provision fails to consider pipe diameter, and considering only length without considering volume is unreasonable. For example, a 35-kilometer pipe with a diameter of 1416 mm and a pipe with a diameter of 219 mm have a volume difference of more than 40 times, and the amount of air inside the pipe differs greatly, resulting in different pressure changes due to temperature variations. The test pipe volume is inversely proportional to the rate of pressure change; that is, the larger the volume, the smaller the rate of pressure change (i.e., the pressure drop rate). Existing standards do not consider the size of the test pipe diameter or the volume of the test section, and all test pressure stabilization requirements, test times, and acceptance criteria are the same, which is clearly unscientific and inappropriate.

[0043] Article 8.4.5.1.2 of the "Pressure Piping Specification for Long-Distance Pipelines" (GB / T34275-2024) stipulates that "the capacity of a pipe section should not exceed 2.5 × 10⁻⁶". 4 m 3The length should not exceed 35km. The sealing test duration is 24 hours. While this clause in the standard considers the test section pipe volume, the given pipe volume is potentially too large. The standard fails to mention the impact of excessive pipe volume on thermal inertia, affecting the thermal balance of the test section and the sealing test duration; it also fails to describe the impact of excessive pipe volume on pressure change sensitivity and leak detection accuracy; and it does not provide information on the impact of excessive pipe volume on pressure transmission and response hysteresis.

[0044] Current standards and construction techniques fail to provide scientific answers and solutions to the above questions, therefore the clauses regarding the hydrostatic testing of long-distance pipelines in the current standards are open to discussion.

[0045] Judging from the current situation of pipeline construction, a newly built gas pipeline experienced a serious accident during operation due to weld defects, resulting in a pipeline explosion. This was a major operational safety accident that escalated from a construction quality issue. This reveals that the pipeline did not fulfill its final inspection and control role during the hydrostatic testing process, thus reflecting deficiencies in the pressure testing standards and procedures.

[0046] In view of this, this application provides an innovative method and related equipment for hydrostatic testing of long-distance pipelines, comprising: dividing the long-distance pipeline into test sections based on relevant parameters to obtain a first-stage pipe section; filling the pipe section of this stage with water according to water filling control conditions to obtain a second-stage pipe section; continuously injecting water into the second-stage pipe section to raise its pressure to the thermal equilibrium pressure to obtain a third-stage pipe section; pressurizing the third-stage pipe section to obtain a first test result and a fourth-stage pipe section; calculating the amount of air present in the pipe section in response to the first test result being qualified to obtain a second test result and a fifth-stage pipe section; conducting a sealing test on the pipe section in response to the second test result being qualified to obtain a third test result; and determining the quality of the long-distance pipeline to be qualified in response to the third test result being qualified. This method can improve the accuracy of quality testing of long-distance pipelines.

[0047] The method provided in this application has undergone repeated practice, optimization, and refinement in multiple project sites. Combining cutting-edge fluid mechanics theory and innovative construction organization strategies, it has successfully explored a novel and highly efficient innovative process for hydrostatic testing of long-distance pipelines. It not only accurately overcomes the aforementioned challenges but also ensures the quality of every inch of the pipeline with superior testing precision, injecting strong momentum into the high-quality development of long-distance pipeline projects. Highlighting its technological originality, practicality, and patentability, the method has been structurally designed according to professional logical levels, making it highly valuable for promotion and patent protection.

[0048] The method provided in this application is applicable to the hydrostatic testing technology of long-distance pipelines for important energy sources such as petroleum, refined oil, natural gas, coal gasification, liquefied natural gas (LNG), hydrogen, mineral slurry, and water transportation, and has a wide range of uses.

[0049] Figure 1 A schematic flowchart of an exemplary long-distance pipeline quality inspection method 100 according to an embodiment of this application is shown.

[0050] like Figure 1 As shown, in some embodiments, in the first stage, a pressure test segmentation table can be created for the long-distance pipeline based on relevant parameters (step 101) to obtain the pipeline segments for the first stage. These relevant parameters include the elevation difference of the long-distance pipeline. Based on the pipeline material characteristics and terrain undulation data, the pressure test segments are precisely divided to ensure reasonable stress on each segment and avoid overloading of weak points. Pressure test segmentation principles are established, and a pressure test cross-sectional diagram for each segment is created to precisely control the test pressure.

[0051] Existing methods for pressure testing segmentation divide pipelines into sections based on a 35-kilometer baseline, meaning that pipelines no longer than 35 kilometers are classified as a single segment. In this embodiment, the volume of each segment is also considered when dividing the pipeline for pressure testing. This more scientifically standardizes pressure testing segmentation, avoiding the pitfall of considering only length and neglecting crucial factors such as pipe diameter, volume, air content, and temperature variations. Considering only length without considering volume is unreasonable. Therefore, it is necessary to deepen and refine the relevant aspects of pressure testing, taking into account factors such as air content, temperature, pipe capacity, and the maximum elevation difference within the test section to determine the test section length, and analyzing the impact of temperature and air content on the pressure test, thus addressing the shortcomings of current standards. This will improve the accuracy and reliability of pressure testing, providing a solid guarantee for the quality control of long-distance pipelines.

[0052] The pipeline pressure testing segmentation method in this application focuses on limiting the volume of the test section (also known as the test section or pressure testing segment). It also considers the length of the test section, fully taking into account key factors such as the volume of different pipe diameters, the amount of air present, and temperature changes. This more scientifically standardizes the pressure testing segmentation. The division of test sections should also consider minimizing the number of pipe joints (pipe welds that cannot participate in pressure testing) in this project, and, where relevant conditions permit, the test section should be as long as possible. The principle for setting up the pressure testing segments is shown in the figure below.

[0053] Figure 2 A cross-sectional view of an exemplary pressure testing pipe section according to an embodiment of this application is shown. This cross-sectional view of the pressure testing pipe section can be established based on parameters from the design drawings of a long-distance pipeline.

[0054] like Figure 2As shown, this cross-sectional diagram illustrates the pressure distribution at specific points along a 30km pipe section, including the pressure at the beginning and end of the pipe section, as well as the pressure at the highest and lowest elevations of the pipe section.

[0055] In determining the volume of the test pipe section, in some embodiments, the following parameter values ​​can be determined:

[0056] (1) The volume of the test section should ideally be controlled at V = 5000 m³. 3 Left and right (preferred).

[0057] (2) The volume of the test pipe section V ≤ 10000 m³ 3 (Recommended limit values).

[0058] (3) The length of the test pipe section L ≤ 35km (national standard requirement).

[0059] (4) The volume of the test pipe section V = 10000~25000m³ 3 (It is not recommended to use this table; the sealing test time needs to be increased, and the pressure stabilization time should be 48-120 hours).

[0060] In some embodiments, when performing pressure testing on long-distance pipelines, a target threshold for judging large elevation differences in the pipeline segment and the maximum allowable elevation difference (e.g., target elevation difference) can be set. For example, the target threshold can be set to 150m. This threshold is an empirical reference value and needs to be used in conjunction with formula calculations in actual engineering, complementing the results of the formula calculations to form multiple criteria. When the elevation difference of the long-distance pipeline is less than or equal to the target elevation difference, the long-distance pipeline is pressure tested and segmented to obtain the first stage of the pipeline segment.

[0061] The formula for calculating the maximum allowable elevation difference (target elevation difference) of a pipe section is:

[0062] ΔH max =(P allow -P test ) / ρg

[0063] Where, ΔH max P represents the target elevation difference, which is the maximum allowable elevation difference for each pipe segment. allow The pressure at the lowest point of the pipeline must not exceed the material's allowable pressure (in Pa), which is related to the properties of the pipeline material. test The pressure represents the test pressure (in Pa), and ρ represents the density of water (1000 kg / m³). 3 ), where g represents the acceleration due to gravity (9.81 m / s²). 2 ).

[0064] The above calculation formula is an engineering expression of hydrostatic pressure balance, which can provide a quantitative basis for pressure testing segmentation. In the above calculation formula, P allow -P test This represents the portion of the test pressure exceeding the design pressure, indicating the additional pressure margin the pipeline must withstand during the test. This difference is converted into an equivalent hydrostatic head using the ρg table (specific weight of water), used to determine whether the difference in pipe section elevation would cause the test pressure to exceed the material strength. P allow It is a core pressure parameter in pipeline system design, directly related to the strength and safety of pipe materials.

[0065] The embodiments of this application use pipe volume as the main factor in dividing pipe sections, and scientifically control the influence of temperature changes and changes in the amount of air in the pipe on the test pressure during pipe testing.

[0066] For long-distance pipeline sections with elevation differences greater than or equal to the target threshold, transient analyses such as water hammer and cavitation should be performed to ensure test safety. Understandably, in practical applications, a comprehensive judgment needs to be made considering specifications, safety factors, and dynamic operating conditions, and hydraulic transient analysis should be used for verification when necessary. Stress analysis should be conducted by engineering designers, and implementation should proceed only after expert approval.

[0067] By combining quantitative parameter definition with engineering practice, large drop pipe sections can be scientifically identified, providing a technical benchmark for the safe implementation of hydrostatic testing. Through systematic fluid control and rigorous process management, the risk of water hammer under complex terrain conditions can be effectively eliminated.

[0068] In some embodiments, the relevant parameters may also include the wall thickness of the long-distance pipeline, pipe material characteristics, and topographic parameters of the pipeline's location. Based on factors such as pipe material characteristics, topographic relief data, pipeline elevation difference, water source conditions in the test section, test water discharge (or water diversion to another pipe section), test section length, test section volume, crossing conditions within the test section, location of line valve chambers, population density in the test section, and the ease with which construction equipment should be positioned at the segmentation points, the test pressure sections are precisely divided to ensure each section is reasonably divided, avoid overloading weak points, and accurately control the test pressure.

[0069] After pressure testing and segmentation of the long-distance pipeline to obtain the first-stage pipe section, in some embodiments, in the second stage, the first-stage pipe section can be filled with water according to water filling control conditions (step 102) to obtain the second-stage pipe section. These water filling control conditions are determined based on the water injection rate and back pressure during the water filling process. In some embodiments, the water injection rate, back pressure, and continuous water injection requirements during the water filling process can be controlled based on the test section pipe volume, air residual threshold, and temperature change rate.

[0070] Strict control of the water injection process in the test section is required to prevent excessive air from entering the pipeline. Water injection technical requirements are specified. This application's embodiments propose pipeline wetting, water injection filtration, water injection metering, pig isolation, control of operating speed, back pressure water injection at large drops, and uninterrupted water injection throughout the entire process, as detailed below:

[0071] (1) Pipeline cleaning and diameter measurement confirmation: Before the test, additional work will be done to confirm the pipeline. Before the actual pipeline water injection operation, the pipeline cleaning and diameter measurement should be considered to identify any possible geometric anomalies in the pipeline and confirm that the pipeline is clean and free of deformation. The method of diameter measurement is to use an aluminum caliper plate to pass through the pipeline. If there is no deformation, damage and wrinkles, it is considered qualified.

[0072] (2) Requirements for test water: The quality and source of the test water should be determined. The water source should be clean and non-corrosive. Water containing sediment, with a non-neutral pH level, or with high salinity may be harmful to pipes, valves, and equipment and should not be used unless filtered or treated. The test water should be clean, with a pH value preferably between 6 and 9, non-corrosive, with total suspended solids not exceeding 50 mg / L, and a maximum salt content not exceeding 2000 mg / L. To prevent sewage and debris from entering the pipeline, a settling tank should be installed, and a filter should be installed at the pump inlet. The water should only be injected into the pipeline after meeting the requirements. The water source, water intake location, drainage point, and drainage location should be listed according to the specific site conditions.

[0073] (3) Flow meter setting: A flow meter is installed on the test pipeline to monitor and maintain the predetermined filling water rate. When the pressure and filling water rate decrease, the test personnel are allowed to adjust the flow rate, thereby adjusting the pressure value and filling water rate. At the same time, it also helps to compare the calculated and actual filling water volume.

[0074] (4) Pipeline wetting: The water injection pump is connected to the test head via a valve, and the valve's installation position should be suitable for the length of the pipeline pig. During pipeline pressure testing and water injection, a mechanical method is used: adding an isolator can effectively remove air from the pipe during the pressure test and water filling. The pipeline pig should be installed before water injection. First, inject approximately 5% of the total water volume of flushing water into the pipeline in front of the water injection pig (the amount should be determined based on the pipe diameter, length, and terrain undulation of the test section, generally not exceeding 300m). 3To wet the pipeline and reduce air content during water injection, after zeroing the flow meter, inject water into the pipeline behind the water injection pig. The water injection pig is pushed out of the test head by the injected water. Launch a second water injection pig in a similar manner to prevent cavitation. Return the flow meter to 0 again and continue injecting water to push the water injection pig and flushing water, using water to propel the pig and fill the entire pipeline section. This completes the water injection of the test section. When more than one pig is needed, use a liquid section of sufficient volume to separate the pigs to ensure that air is not trapped in the test liquid after the last pig. When both pigs arrive at the receiving end, drain the injected flushing water.

[0075] (5) Control of water injection rate:

[0076] a) Preventing Water Hammer: During water injection, the travel speed of the water injection pig must be controlled to prevent it from accelerating on downhill sections, ensuring uninterrupted water flow behind the pig. In areas with significant terrain undulations, back pressure should be established to maintain sufficient back pressure for controlling the pig's travel speed (determined based on the longitudinal section elevation of the test section). The back pressure is determined according to the actual elevation, and the back pressure medium is air. The water injection speed should not be too fast to prevent air from being drawn in during excessive pig movement. The travel speed of the water injection pig is controlled by adjusting the opening size of the vent valve at the end of the test section to ensure sufficient back pressure to prevent accelerated travel on downhill sections, thus ensuring uninterrupted water flow behind the pig during injection. When the elevation difference of the water injection section is large, compressed air should be injected in front of the water injection pig to make the air pressure in the pipe equal to the static pressure of the water elevation difference, thereby controlling the walking speed of the pig.

[0077] b) Reduce the amount of air remaining in the pipe: Based on the principles of fluid mechanics, we can see that:

[0078] (b-1) When the pressure test filling speed is relatively slow and the water flow inside the pipe is in a laminar flow state, the movement of water inside the pipe is limited to friction and deformation between particles. This friction and deformation cannot allow the water flow to carry air, and the vents at both ends of the pressure test pipe section cannot completely remove the air from all the high points inside the pipe.

[0079] (b-2) When the pressure test and water filling speed increases to a certain extent, and the water flow inside the pipe is at least in a turbulent mixed friction state, the movement of water inside the pipe involves not only friction and deformation between particles, but also collisions and mixing. This collision and mixing can cause the water flow to entrain air. If the purging time is long enough and the amount of water discharged is large enough, all the air inside the pipe can be entrained by the water flow. However, in actual engineering, it is not advisable to discharge too much water.

[0080] c) Recommended practice: The water injection process in the water pressure test is a very important procedure. In order to prevent water hammer and reduce the amount of air in the pipe, it is necessary to scientifically find a suitable water injection rate. It is recommended that the maximum travel speed of the water injection pig should be limited to about 3-5 km / h.

[0081] (6) Uninterrupted water injection: Once water injection begins in the pressure test section, it should be carried out as a continuous process. Try not to stop water injection as much as possible, and make reasonable arrangements for power supply, water supply, equipment and other aspects of work until all pipe sections are filled with water, so as to avoid air entering the pressure test section due to the cessation of water injection.

[0082] To calculate the arrival time of the pipeline pig, flushing water should be drained through the drain pipe at the receiving section. Once the pig is seen arriving, the drain valve should be closed slightly. The drain valve should be closed immediately after the water-filled pig arrives. Air ahead of the pig should be released through the vent valve. The water injection volume should be monitored continuously to calculate the pig's position.

[0083] (7) Recording: During the water injection process, parameters such as the launch and arrival time of the pig, water injection pressure, water injection volume, ambient temperature, surface temperature, pipe wall temperature and inlet temperature should be accurately recorded.

[0084] The water filling process in the pressure test section is a process of controlling the amount of air in the pipeline. It specifies the technical requirements for water filling, including specific requirements for pipeline wetting, water filling filtration, water filling metering, pig isolation, control of operating speed, back pressure water filling at large drops, and uninterrupted water filling throughout the entire process.

[0085] In some embodiments, water filling control conditions may include:

[0086] (1) Use a water injection pig to fill the first stage of the pipeline with water to obtain the second stage of the pipeline. The walking speed of the water injection pig is controlled at 3-5 km / h, and the back pressure of the first stage pipeline is controlled to be greater than or equal to 0.3 MPa.

[0087] (2) The flow meter is used to measure the water throughout the filling process, and the accuracy rate is not less than 0.5% of the pressurized volume.

[0088] (3) Before filling with water, the pipeline should be moistened. The amount of moistening water should be about 5% of the volume of the pipeline section in the first stage.

[0089] After the pipeline is filled with water, in some embodiments, in the third stage, the pipe sections in the second stage (i.e., the pipe sections after water filling) can be continuously filled with water to increase the pressure of the pipe sections in the second stage to the thermal equilibrium pressure, and a pipe section table in the third stage is obtained (step 103). The thermal equilibrium time depends on the pipe diameter and the total volume of the pipe body, and the temperature of the pipe body along the line is measured every once in a while. When there is no obvious change or the temperature change ≤ 1 °C / h, it is considered that the thermal equilibrium is effective. The thermal equilibrium procedure of the test pipe section is first introduced in the embodiments of the present application, and different thermal equilibrium times for different pipe diameters are given. The thermal equilibrium time represents the time for continuously filling water into the pipe section so that the pressure of the pipe section rises to the thermal equilibrium pressure.

[0090] The thermal equilibrium time is determined by thermal stability evaluation under the sealing test pressure. The thermal equilibrium times corresponding to different pipe diameters are as follows:

[0091] For pipe sections with a diameter less than or equal to 400 mm, the thermal equilibrium time is 24 hours;

[0092] For pipe sections with a diameter greater than or equal to 400 mm and less than or equal to 750 mm, the thermal equilibrium time is 48 hours;

[0093] For pipe sections with a diameter greater than or equal to 750 mm and less than or equal to 800 mm, the thermal equilibrium time is 72 hours.

[0094] After reaching the thermal equilibrium pressure, in some embodiments, in the fourth stage, the pipe sections in the third stage can be pressure increased to obtain a first test result and the pipe sections in the fourth stage (step 104), so as to conduct a strength test on the pipe sections in the third stage.

[0095] Different strength test pressures correspond to different test times (steady pressure times). Thus, when conducting a strength test on the pipe sections in the third stage, in some embodiments, the pressure of the pipe sections in the third stage can be increased to the target pressure. When the steady pressure time of the pipe sections in the third stage reaches the target time at the target pressure, the first pressure drop value of the pipe sections in the third stage is determined. Furthermore, based on the first pressure drop value, a first test result and the pipe sections in the fourth stage (i.e., the pipe sections after the strength test) can be obtained. If the first pressure drop value is less than 1 bar (or 0.1 MP), the first test result is qualified; otherwise, the first test result is unqualified.

[0096] In some embodiments, in the fifth stage, when the first test result is qualified, an air presence test can be conducted on the pipe sections in the fourth stage to obtain a second test result and the pipe sections in the fifth stage (i.e., the pipe sections after the air presence test) (step 105).

[0097] When conducting the air presence test on the pipe section in the fourth stage, in some embodiments, the discharged water volume corresponding to reducing the water pressure in the pipe section of the fourth stage by 1 bar can be calculated. The calculation formula for the discharged water volume is as follows:

[0098] V1 = V(X+(D / eE))

[0099] Where, V1 represents the discharged water volume, V represents the total volume in the pipe section of the fourth stage, x represents the absolute compressibility coefficient of drainage according to pressure and temperature, D represents the outer diameter of the pipe section of the fourth stage, e represents the equivalent thickness of the pipe section of the fourth stage, and E represents the Young's modulus of the pipe section of the fourth stage.

[0100] The actual discharged water volume is discharged into a standard measuring cylinder, and the actual discharged water volume (m) is recorded. The second pressure drop value (i.e., the theoretical pressure drop) of the pipe section in the fourth stage is calculated according to the discharged water volume. The calculation formula for this second pressure drop value is as follows:

[0101] ΔP0 = m / V1

[0102] Where, ΔP0 represents the second pressure drop value, m represents the actual discharged water volume, and V1 represents the discharged water volume.

[0103] Meanwhile, the third pressure drop value of the current pipe section in the fourth stage is detected and compared with the calculated second pressure drop value. According to the ratio of the third pressure drop value to the second pressure drop value, the second test result and the pipe section in the fifth stage (i.e., the pipe section after the air presence test) are obtained.

[0104] For pipe sections with a diameter greater than or equal to 400 mm, if the ratio of the third pressure drop value to the second pressure drop value is greater than or equal to 0.95, the second test result is qualified; otherwise, exhaust measures need to be taken. For pipe sections with a diameter less than 400 mm, if the ratio of the third pressure drop value to the second pressure drop value is greater than or equal to 0.9, the second test result is qualified; otherwise, exhaust measures need to be taken.

[0105] In the embodiments of this application, based on the basic theories of elasticity mechanics and hydraulics, a calculation method is derived and established, establishing the relationship and equation between the pressure and volume in the water body inside the pipeline. A more scientific calculation method is used to calculate the content of air in the pipe. Whether this quantity value is within the allowable range will be the criterion for judging whether the air presence test is qualified. A scientific method is used to judge whether the pipeline can proceed to the next process, the sealing test, so as to correctly evaluate the result of the pipeline water pressure test.

[0106] For the air presence test, the test medium is discharged into a standard measuring instrument (measuring cylinder), and at the same time, the test pressure value is measured. The pressure and volume of the removed test medium are used to calculate the theoretical pressure drop value through calculation. By comparing the theoretical pressure drop with the actual pressure drop, it can be used to determine whether the residual air volume in the test section meets the requirements of the sealing test.

[0107] In the sixth stage, if the second test result is qualified, that is, the air presence test result is qualified, in some embodiments, a sealing test is performed on the pipe section of the fifth stage to obtain the third test result (step 106).

[0108] It should be noted that pressure and temperature must be measured at least 5 times along the test section within 24 hours (at least 6 thermometers must be checked), and records must be kept.

[0109] When conducting a sealing test on the fifth-stage pipe section, in some embodiments, the average expansion coefficient of the fifth-stage pipe section can be calculated. The formula for calculating the average expansion coefficient is as follows:

[0110] K=(μ-γ) / (X+(D′ / e′E′))

[0111] Where K represents the average expansion coefficient, μ represents the water volume expansion coefficient, γ represents the volume expansion coefficient of the fifth stage pipe section, X represents the absolute compressibility coefficient of drainage based on pressure and temperature, D′ represents the outer diameter of the fifth stage pipe section, e′ represents the equivalent thickness of the fifth stage pipe section, and E′ represents the Young's modulus of the fifth stage pipe section.

[0112] Based on the average expansion coefficient, the fourth pressure drop value (pressure drop caused by temperature change) of the pipe section in the fifth stage is calculated. The formula for calculating this fourth pressure drop value is as follows:

[0113] ΔP=fK(T1-T2)

[0114] Where ΔP represents the fourth pressure drop value, f represents the temperature change gradient coefficient of the water in the fifth stage pipe section, T1 represents the temperature of the fifth stage pipe section at the start of the sealing test, and T2 represents the temperature of the fifth stage pipe section at the end of the sealing test.

[0115] Based on the fourth pressure drop value, calculate the fifth pressure drop value (theoretical pressure drop value) and the sixth pressure drop value for the pipe section in the fifth stage. The formula for calculating the fifth pressure drop value is as follows:

[0116] H = δf / f|ΔP| + 0.2fK

[0117] Where δf / f represents the dispersion coefficient of f.

[0118] The formula for calculating the sixth pressure drop is:

[0119] delta P=P1-P2-ΔP

[0120] Where delta P represents the sixth pressure drop value, P1 is the pressure value of the pipe section in the fifth stage at the start of the sealing test, and P2 is the pressure value of the pipe section in the fifth stage at the end of the sealing test.

[0121] Perform a sealing test on the pipe section in the fifth stage according to the fifth pressure drop value and the sixth pressure drop value to obtain the third test result. If the sixth pressure drop value is less than the fifth pressure drop value table (i.e., delta P < H), the third test result is qualified.

[0122] In the embodiment of the present application, the sealing test detects leakage by associating pressure with temperature. The pressure stabilization time for the sealing test is 24 hours. The temperature and pressure are measured at the start, during, and end of the test to obtain the temperature change value and the pressure change value (measuring the actual pressure drop value ΔP), and the theoretical pressure drop value (H) is calculated. The theoretical pressure drop value is calculated based on relevant parameters such as the total volume of the pipe body, the pipe diameter / wall thickness ratio, the temperature change value, the compression coefficient of water, the expansion coefficient of the steel pipe, and the elastic modulus of the steel. When the pressure drop ratio is less than or equal to 1, the sealing test is confirmed to be qualified.

[0123] In some embodiments, the passing criteria for the extended 1-hour test are:

[0124] P2 - P3 < 0.5F

[0125] Where, F is the minimum leakage within 1 hour, F = q / V(x + (D' / e'E')), V represents the volume of the pipe section, q represents the leakage per hour. When the test pressure P ≤ 100 bar, then q = (1 / 15)×(p + 5); when the test pressure P > 100 bar, then q = 7; where, P2 is the pressure before the 1-hour extension, and P3 is the pressure after the 1-hour extension.

[0126] In the seventh stage, if the first test result, the second test result, and the third test result are all qualified, it can be determined that the quality of the long-distance pipeline is qualified (step 107).

[0127] After the test is completed, a test report including the following parameters can be generated: sectional parameters (length, elevation difference, pipe volume), P / V diagram slope deviation value, thermal equilibrium time and temperature change rate, ratio of the air presence test drainage volume to the theoretical calculation, strength test pressure and pressure drop, sealing test K value and calculated value of delta P. The data storage period can be greater than or equal to 10 years, supporting the archiving of completion data.

[0128] In some embodiments, pressure-volume change curves can also be plotted in real time. In long-distance pipeline hydrostatic testing, the P / V curve method is very effective in determining the air content inside the pipe. When air is present in the pipeline, the P / V curve will exhibit different characteristics in the initial pressurization phase compared to the case without air. In an ideal state (without air), water can be considered incompressible, and pressure and volume have a essentially linear relationship. However, if air is present, due to its compressibility, the pressure increase is relatively slow in the initial pressurization phase. The P / V curve can reflect changes in the mechanical state of the pipeline to some extent. Within the ideal elastic range, pressure and volume change are approximately linear. When the test pressurizes, the pressure gradually increases, and when the pipeline material begins to yield, its rate of volume change suddenly increases. This is because in the yielding stage, the stress-strain relationship of the material no longer follows the laws of the elastic stage; the pipeline undergoes irreversible plastic deformation, and the slope of the P / V curve changes significantly. Therefore, plotting the P / V curve can monitor both the amount of air present and pipeline yielding.

[0129] The amount of air in the pipeline is determined by calculating the P / V slope. The slope K = ΔP / ΔV, which is the ratio of the pressure change rate to the volume change rate. The actual P / V curve is compared with the theoretical P / V curve. If the slope deviation does not exceed 10%, the amount of air is considered acceptable.

[0130]

[0131] Slope ratio: K 实际 / K 理论 ≥0.9.

[0132] By combining theoretical calculations with experimental experience, the proportion of air inside the tube can be roughly determined based on the shape and slope of the curve. Using Boyle's law, the slope of the P / V curve is calculated, and a comparison is made between the actual and theoretical slopes. If the slope deviation does not exceed 10%, the amount of air present is considered acceptable.

[0133] In long-distance pipeline hydrostatic testing, especially in areas with significant terrain undulations and elevation differences, how can water hammer be avoided during water intake and drainage? Water hammer occurs when a sudden change in fluid velocity leads to a rapid change in pressure. It is easily triggered by abrupt changes in water flow velocity or gas-liquid two-phase flow, potentially damaging the pipeline. This risk is even higher in areas with significant terrain undulations. Measures to prevent water hammer include: water injection flow control measures; water injection back pressure control technology; graded control of pressure relief rate; the principle of dividing test sections according to elevation differences; and the maximum allowable elevation difference for each section.

[0134] In some embodiments, the measures for preventing and controlling water hammer may include hierarchical control of the pressure relief rate. For example, in the first stage, the pressure is relieved to 50% of the test pressure at a rate ≤ 0.6 MPa / min; in the second stage, the pressure is relieved to 20% of the test pressure at a rate ≤ 0.3 MPa / min; in the third stage, the pressure is relieved to atmospheric pressure at a rate ≤ 0.1 MPa / min.

[0135] In the long-distance pipeline quality inspection method according to the embodiments of the present application, each process can be reasonably controlled by using scientific and technological parameters. From the selection of equipment and measuring instruments, the setting of the test site, the scope of the pressure test restricted area, the determination of test segments, the requirements for pipeline wetting, the pipeline water injection rate, the pressure increase rate of the test section, the thermal balance of the test section, the strength test, the air presence test, the sealing test, the pressure relief and drainage rate, the water hammer prevention measures, and the determination of the large drop of the pipeline, etc., based on relevant domestic and international standards and the experience accumulated in long-term engineering construction, all advanced technical indicators are applied with process parameters to conduct test control on this process.

[0136] For the method provided in the present application, corresponding theoretical formulas are set for scientific calculation of the technical requirements for pressure testing, the equivalent wall thickness of the pipeline, the maximum allowable height difference of the pressure test pipe section, the water injection time, the water injection flow rate, the increased water volume due to pipeline pressure increase, the slope of the P / V curve, the strength test, the air presence test, the sealing test, the one-hour extended test, the hydraulic calculation for large drop determination, and the maximum allowable height difference of each section divided by the height difference for large drop, etc.

[0137] Precise calculations and measurements are used for the strength test and the sealing test to determine whether the test is qualified. For the sealing test, the theoretical pressure drop value is calculated based on relevant parameters such as the total volume of the pipe body, the pipe diameter / wall thickness ratio of the pipeline, the temperature change value, the compression coefficient of water, the expansion coefficient of the steel pipe, and the elastic modulus of steel. The theoretical calculation of the sealing test includes: calculation of the K value, calculation of the pressure drop (ΔP) caused by temperature change, calculation of the theoretical pressure drop (H), and calculation of delta P. The main test route: measurement - calculation - comparison - verification of results. When the pressure drop ratio is less than or equal to 1, the sealing test is confirmed to be qualified.

[0138] Figure 3 The flowchart shows the schematic flow of an exemplary hydrostatic test procedure according to an embodiment of the present application.

[0139] As Figure 3 shown, the hydrostatic test procedure includes a test preparation form (specifically including: technical preparation, personnel preparation, equipment and instrument preparation, on-site preparation), hydrostatic test segments (specifically including: meeting the design requirements, controlling the pipe volume within 5000 m 3Left and right are both suitable. Draw the cross-sectional diagram of the test section. For the large drop test section, the pressure at the high point of the pipeline should not be less than the design requirements, and the static water pressure at the low point needs to be calculated. When calculating the pressure at the low point of the pipeline, the circumferential stress it bears should not exceed 95% of the minimum yield strength of the pipe material. The pressure at the beginning and end of the test section should be calculated according to the cross-sectional diagram and the pressure should be controlled. Document review (steel pipe certificate, welding records, non-destructive testing report, etc.), water hammer prevention measures and pipeline large drop determination table (which describes water hammer prevention measures, water injection flow control measures, typical large drop pipeline parameters from engineering practice experience, large drop judgment formula, multi-section water injection and drainage method suggestions, water hammer phenomenon characteristics, water hammer generation mechanism, water hammer damage mode, water hammer prevention measures, water injection flow control measures, water injection back pressure technology measures, large drop section drainage stage control measures, large drop definition, typical large drop pipeline parameters from engineering practice experience, hydraulic calculation benchmark, test section segmentation principle, recommended practice for large drop test section), test section pipe volume calculation ( Specifically, this includes: analysis of the impact of the test section volume on the test results; accurate calculation of the volume of pipe welds, launching and receiving tubes, etc.); water injection into the test section (specifically including: water quality evaluation, pipe wetting, pig isolation, minimizing air content in the filling water, water metering, water filling rate control, water hammer prevention, and uninterrupted water filling); pressurization of the test section (specifically including: pressure measurement and pressurization rate control); thermal balance of the test section (specifically including: data collection of pressure and water volume, calculation of the theoretical water volume for pipe pressure testing, calculation of the slope of the P / V curve, curve plotting, analysis of the relationship between the total amount of air trapped in the test section and the P / V curve, comparison of the actual P / V curve with the theoretical P / V curve, and assessment and judgment of air content; determining different thermal balance times, temperature measurements, and thermal balance effect evaluation according to different pipe diameters); and strength testing (specifically including: temperature and pressure measurements, pressure drop calculation, strength test effect evaluation, and qualification determination). If the strength test results are qualified, the air presence test will continue; if they are unqualified, the pressure will be released. After the strength test results are obtained, the pipe section is depressurized to the sealing test pressure (specifically including pressure measurement and depressurization rate control).

[0140] The air presence test (specifically includes: temperature and pressure measurement, releasing and measuring a certain volume (V1) of water into the test pipeline, calculating the water discharge meter (V1), comparing the calculated theoretical pressure drop with the measured actual pressure drop to determine the air content in the pipe, evaluating the effectiveness of the air presence test, and determining whether it is qualified). If it is qualified, the sealing test is continued; if it is unqualified, the pipe section is depressurized.

[0141] Sealing test (specifically including: measuring temperature and pressure at the start, during, and end of the test to obtain temperature change values and pressure change values. Calculating the K value, the pressure drop (ΔP) caused by temperature change, the theoretical pressure drop (H), the calculation of delta P, the extended one-hour test calculation, etc. based on relevant parameters such as the total volume of the pipe body, the pipe diameter / wall thickness ratio, temperature change value, water compression coefficient, steel expansion coefficient, and steel elastic modulus, and calculating the theoretical pressure drop value. Comparing the theoretical pressure drop value with the actual pressure drop to determine whether the sealing test is qualified). If qualified, it can be determined that the pipe section quality is qualified; if unqualified, the pipe section is depressurized.

[0142] As Figure 3 shown, after the sealing test is qualified, the pipe section is depressurized to drain the pressure test water meter (specifically including: releasing the pressure test water strictly in accordance with environmental protection requirements, controlling the drainage rate and conducting safety monitoring and environmental protection monitoring, and preventing water hammer throughout the drainage process to ensure pipeline safety, and suggesting a multi-paragraph drainage method). After the pressure test water is drained, the test ends.

[0143] Taking an oil pipeline project as an example to illustrate the technical effects of the embodiments of the present application, the pipeline is 269 kilometers long, with a design pressure of 80 bar, the pipeline material is X60, and the pipeline diameter and its wall thicknesses are 6.39 mm, 7.77 mm, and 11.66 mm respectively, with a variable wall thickness design. The whole line crosses 16 large and medium-sized rivers, 44 highways, and 7 railways. Now, only taking the data of the second pressure test section of this project as an example, the length of the second pressure test section is 14.568 km, and the pipe content volume is 2782.9368 m 3 . In the strength test, the pressure in the pressure test section rises to 88 bar, the pressure stabilization time is 4 hours, and the pressure drop value is 0 bar. The strength test is judged as "qualified".

[0144] In order to reduce the pressure by 1 bar in the pipeline of the test section, under the condition that the pressure in the pipe is 80 bar, 230 liters of water is discharged. Calculate the theoretical pressure drop ΔP0 = 1.082893114 bar. Use a pressure balance to measure the actual pressure drop ΔP1 = 1.1 bar. Calculate ΔP1 / ΔP0 = 1.01375. The air presence test judgment standard: If ΔP1 / ΔP0 is greater than or equal to 0.95 (for pipes with a diameter greater than or equal to 400 mm), it is qualified. The calculation result is greater than or equal to 0.95, and the air volume presence test result is "qualified".

[0145] For the sealing test, the pressure in the test section is 79.5 bar, and 4 thermometers are set up throughout the line. The pipeline temperature is measured 5 times during the test and the average value is taken. The data is as follows:

[0146] The starting temperature t1 of the test: The 4 thermometers are respectively: 28 °C; 26 °C; 25 °C; 26.5 °C;

[0147] The average temperature t1_avg at the start of the test is 26.38°C;

[0148] The temperature t2 at the end of the test: The readings of the 4 thermometers are respectively: 28°C; 25.5°C; 25°C; 26.5°C;

[0149] The average temperature t2_avg at the end of the test is 26.25°C;

[0150] Calculate the pressure drop ΔP caused by the temperature change based on the temperature change: It is calculated that ΔP = 0.157 bar.

[0151] Calculation of the K value: It is calculated that K = 3.079.

[0152] Calculation of the theoretical pressure drop H: It is calculated that H = 0.234 bar.

[0153] Calculation of delta P: It is calculated that delta P = 0.157 bar. Delta P is the actual pressure drop in the tightness pressure test section, considering and removing the pressure change caused by the temperature change.

[0154] Qualified standard for the seal test: If delta P < H, this test is judged as "qualified".

[0155] For the above strength test, air presence test, and seal test, the calculation results are excellent, and this section of the water pressure test is "qualified".

[0156] The above exemplary project has been in operation for many years with good working conditions and has never experienced any shutdowns or safety accidents due to quality problems, which fully demonstrates that the water pressure test of this pipeline project has played an important role as the last comprehensive quality inspection. It ensures a comprehensive inspection of the quality of the entire pipeline system, including the quality of pipe materials, welding quality, and fitting connection quality, etc., and is truly a quality verification of the integrity of the pipeline system.

[0157] The method provided by this application, through precise pressure and temperature monitoring, scientific calculation of the air presence in the pressure test section, comprehensive control of strength and tightness tests, reasonable pressure test procedures, and high-standard test qualification determination, can very reliably guarantee the quality of pipeline installation, effectively reduce the leakage risk during operation, strengthen and prevent the occurrence of safety accidents, and comprehensively extend the service life of the pipeline.

[0158] The method provided in this application introduces for the first time the use of thermal balance in pipeline hydrostatic testing, air presence testing, determination of residual air in the pipeline through P / V slope calculation, and sealing tests to scientifically verify test results. A segmented model is established based on pipeline elevation difference, wall thickness, and terrain parameters. It incorporates typical parameters for pipelines with large elevation differences from engineering practice, a large elevation difference judgment formula (derived from the energy equation), water injection back pressure control technology, graded control of pressure relief rate, and prevention and control measures for the drainage stage of large elevation difference sections. The segmented testing primarily reflects the scientific limitation of the test section volume, avoiding the drawbacks of segmenting test sections by length. Scientific calculations are used to determine test results, solving the industry's technical challenges in hydrostatic testing of long-distance pipelines. The thermal balance time fills a gap in domestic standards, and models for theoretical calculations of air presence testing and sealing test calculations are introduced into engineering for the first time. The method provided in this application exceeds conventional industry techniques and existing hydrostatic testing methods.

[0159] Furthermore, the method provided in this application has been validated in multiple projects with excellent results, ensuring pipeline safety and yielding significant economic and social benefits. This method is suitable for widespread industrial application, is not a purely theoretical solution, and can promote the development of hydrostatic testing technology for long-distance pipelines.

[0160] This innovative process for hydrostatic testing of long-distance pipelines has been rigorously designed and repeatedly verified. It can accurately and efficiently ensure the installation quality and operational safety of long-distance pipelines, effectively filling the gaps in relevant professional technologies in the country and industry, and possessing extremely high innovation and practicality.

[0161] Against the backdrop of ever-increasing energy transmission demand and increasingly stringent pipeline construction standards, this technology is expected to be widely applied in long-distance pipeline projects in various fields such as oil, natural gas, refined oil, hydrogen, mineral slurry, and water transportation. It will provide new technical support for hydrostatic testing of long-distance pipeline projects, promote the advancement of construction technology for long-distance pipeline projects, guide the formulation of hydrostatic testing standards for long-distance pipelines, contribute to the vigorous development of the pipeline industry, and effectively ensure the quality and safety of long-distance pipeline projects, making it highly valuable for promotion.

[0162] Embodiments of this application also provide a computer-readable storage medium storing a computer program, wherein the computer program is configured to execute the steps in any of the above method embodiments when run.

[0163] In one exemplary embodiment, the aforementioned computer-readable storage medium may include, but is not limited to, various media capable of storing computer programs, such as a USB flash drive, read-only memory (ROM), random access memory (RAM), portable hard disk, magnetic disk, or optical disk.

[0164] Embodiments of this application also provide an electronic device, including a memory and a processor, wherein the memory stores a computer program and the processor is configured to run the computer program to perform the steps in any of the above method embodiments.

[0165] In one exemplary embodiment, the electronic device may further include a transmission device and an input / output device, wherein the transmission device is connected to the processor and the input / output device is connected to the processor.

[0166] Obviously, those skilled in the art should understand that the modules or steps of this application described above can be implemented using general-purpose computing devices. They can be centralized on a single computing device or distributed across a network of multiple computing devices. They can be implemented using computer-executable program code, and thus can be stored in a storage device for execution by a computing device. In some cases, the steps shown or described can be performed in a different order than those presented here, or they can be fabricated as separate integrated circuit modules, or multiple modules or steps can be fabricated as a single integrated circuit module. Thus, this application is not limited to any particular hardware and software combination.

[0167] The above description of the embodiments is only for the purpose of helping to understand the method and core ideas of this application. It should be noted that, for those skilled in the art, several improvements and modifications can be made to this application without departing from the principles of this application, and these improvements and modifications also fall within the protection scope of the claims of this application.

Claims

1. An innovative method for hydrostatic testing of long-distance pipelines, comprising: In the first stage, the long-distance pipeline is pressure tested and segmented based on relevant parameters to obtain the pipeline segment of the first stage. The relevant parameters include the elevation difference of the long-distance pipeline. In the second stage, the pipe section of the first stage is filled with water according to the water filling control conditions to obtain the pipe section of the second stage. The water filling control conditions are determined based on the water injection rate and back pressure during the water filling process. In the third stage, water is continuously injected into the pipe section of the second stage to raise the pressure of the pipe section of the second stage to the thermal equilibrium pressure, thus obtaining the pipe section of the third stage. In the fourth stage, the pipe section from the third stage is pressurized to obtain the first test result and the pipe section from the fourth stage. In the fifth stage, in response to the first test result being qualified, an air presence test is performed on the pipe section of the fourth stage to obtain the second test result and the pipe section of the fifth stage; In the sixth stage, in response to the second test result being qualified, a sealing test is performed on the pipe section of the fifth stage to obtain the third test result; In the seventh stage, in response to the third test result being qualified, the quality of the long-distance pipeline is determined to be qualified, so as to complete the hydrostatic test of the long-distance pipeline.

2. The method as described in claim 1, wherein, The step of performing pressure testing and segmenting of the long-distance pipeline based on relevant parameters to obtain the first-stage pipeline segment further includes: In response to the elevation difference of the long-distance pipeline being less than or equal to the target elevation difference, the long-distance pipeline is subjected to pressure testing and segmentation to obtain the pipeline segment of the first stage. The formula for calculating the target elevation difference is: ΔH max =(P allow -P test ) / ρg Where, ΔH max P represents the target elevation difference, which is the maximum allowable elevation difference for each pipe segment. allow The pressure at the lowest point of the pipeline must not exceed the material's allowable pressure (in Pa), which is related to the properties of the pipeline material. test The pressure represents the test pressure, and ρ represents the density of water (1000 kg / m³). 3 ), where g represents gravitational acceleration.

3. The method as described in claim 1, wherein, The step of filling the first-stage pipe section with water according to the water filling control conditions to obtain the second-stage pipe section further includes: The first stage of the pipeline is filled with water using a water injection pig to obtain the second stage of the pipeline. The traveling speed of the water injection pig is controlled at 3-5 km / h, and the back pressure of the first stage of the pipeline is controlled to be greater than or equal to 0.3 MPa. Before filling the pipe section in the first stage with water according to the water filling control conditions, the method further includes: The pipe section in the first stage is wetted, and the amount of wetting water is 5% of the volume of the pipe section in the first stage.

4. The method of claim 1, wherein, The continuous injection of water into the second-stage pipe section to raise the pressure of the second-stage pipe section to the thermal equilibrium pressure, resulting in the third-stage pipe section, further includes: According to the preset thermal equilibrium time, water is continuously injected into the second stage pipe section to raise the pressure of the second stage pipe section to the thermal equilibrium pressure, thereby obtaining the third stage pipe section. The preset thermal equilibrium time is determined based on the pipe diameter of the pipe section in the second stage, and specifically includes: For pipe sections with a diameter less than or equal to 400 mm, the preset thermal equilibrium time is 24 hours; For pipe sections with a diameter greater than or equal to 400 mm and less than or equal to 750 mm, the preset thermal equilibrium time is 48 hours. For pipe sections with a diameter greater than or equal to 750 mm and less than or equal to 800 mm, the preset thermal equilibrium time is 72 hours.

5. The method of claim 1, wherein, The step of pressurizing the pipe section in the third stage to obtain the first test result and the pipe section in the fourth stage further includes: Increase the pressure of the pipe section in the third stage to the target pressure; In response to the target time being reached for the pressure stabilization time of the pipe segment in the third stage under the target pressure, a first pressure drop value for the pipe segment in the third stage is determined; Based on the first pressure drop value, the first detection result and the pipe section of the fourth stage are obtained.

6. The method of claim 1, wherein, The air presence test on the fourth stage pipe section to obtain the second test result and the fifth stage pipe section further include: Calculate the discharge volume corresponding to a 1 bar reduction in water pressure within the pipe section of the fourth stage; Calculate the second pressure drop value of the pipe section in the fourth stage based on the discharged water volume; The third pressure drop value of the pipe section in the fourth stage is detected; The second detection result and the pipe section of the fifth stage are obtained based on the ratio of the third pressure drop value to the second pressure drop value. The formula for calculating the discharge volume is: V1 = V(X + (D / eE)) Wherein, V1 represents the discharged water volume, V represents the total volume within the pipe section of the fourth stage, X represents the absolute compressibility coefficient of the drainage based on pressure and temperature, D represents the outer diameter of the pipe section of the fourth stage, e represents the equivalent thickness of the pipe section of the fourth stage, and E represents the Young's modulus of the pipe section of the fourth stage.

7. The method of claim 1, wherein, The sealing test performed on the pipe section in the fifth stage to obtain the third test result further includes: Calculate the average expansion coefficient of the pipe section in the fifth stage; Based on the average expansion coefficient, calculate the fourth pressure drop value of the pipe section in the fifth stage; Based on the fourth pressure drop value, calculate the fifth and sixth pressure drop values ​​for the pipe section in the fifth stage; A sealing test is performed on the pipe section of the fifth stage based on the fifth pressure drop value and the sixth pressure drop value to obtain the third test result; The formula for calculating the average expansion coefficient is as follows: K=(μ-γ) / (X+(D′ / e′E′)) Wherein, K represents the average expansion coefficient, μ represents the water volume expansion coefficient, γ represents the volume expansion coefficient of the pipe section in the fifth stage, X represents the absolute compressibility coefficient of drainage based on pressure and temperature, D′ represents the outer diameter of the pipe section in the fifth stage, e′ represents the equivalent thickness of the pipe section in the fifth stage, and E′ represents the Young's modulus of the pipe section in the fifth stage. The formula for calculating the fourth pressure drop value is as follows: ΔP=fK(T1-T2) Wherein, ΔP represents the fourth pressure drop value, f represents the temperature change gradient coefficient of the water in the fifth stage pipe section, T1 represents the temperature of the fifth stage pipe section at the start of the sealing test, and T2 represents the temperature of the fifth stage pipe section at the end of the sealing test. The formula for calculating the fifth pressure drop value is as follows: H = δf / f|ΔP| + 0.2fK Where δf / f represents the dispersion coefficient of f.

8. An innovative method for hydrostatic testing of long-distance pipelines, comprising: The pressure testing segmentation module is configured to perform pressure testing and segmentation of the long-distance pipeline based on relevant parameters of the long-distance pipeline to obtain a first-stage pipeline segment, wherein the relevant parameters include the elevation difference of the long-distance pipeline; A water filling module is configured to fill the pipe section of the first stage with water according to water filling control conditions to obtain the pipe section of the second stage, wherein the water filling control conditions are determined based on the water injection rate and back pressure during the water filling process. The first booster module is configured to continuously inject water into the second stage pipe section to increase the pressure of the second stage pipe section to the thermal equilibrium pressure, thereby obtaining the third stage pipe section. The second boost module is configured to boost the pressure of the pipe segment in the third stage to obtain the first detection result and the pipe segment in the fourth stage. An air presence calculation module is configured to calculate the air presence in the pipe section of the fourth stage in response to the first detection result being qualified, thereby obtaining the second detection result and the pipe section of the fifth stage. A sealing test module is configured to perform a sealing test on the pipe section of the fifth stage in response to the second test result being qualified, so as to obtain a third test result; The quality assessment module is configured to determine the quality of the long-distance pipeline is qualified in response to the third test result being qualified, so as to complete the hydrostatic test of the long-distance pipeline.

9. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein, When the processor executes the computer program, it implements the steps of the method according to any one of claims 1 to 7.

10. A computer-readable storage medium storing a computer program, wherein, When the computer program is executed by a processor, it implements the steps of the method according to any one of claims 1 to 7.

Images