Pigging feasibility analysis method and device for class-I gas pipeline

Abstract

The invention discloses a pigging feasibility analysis method and device for a class-I gas pipeline, and the method comprises the steps: obtaining the pipeline information of a to-be-pigged gas pipeline, the information of additional equipment loaded on the gas pipeline, the size information of a receiving and sending ball cylinder on the pipeline, the specification information of a bent pipe, and the specification information of a tee joint; according to the method, according to the acquired information, the first-aid repair leaking stoppage historical operation information, the pipeline type information, the pipeline elevation data and the medium component information of the pipeline conveying gas, whether corresponding pipe cleaning conditions are met or not is judged according to the acquired information, and then whether pipe cleaning is conducted or not is determined. According to the embodiment of the invention, various pigging conditions required to be met by pigging are considered, and the gas pipeline is taken as a whole to provide a pigging feasibility analysis method, so that the reliability of pigging feasibility evaluation is improved.

Description

Technical Field

[0001] This article relates to risk assessment technology, and more particularly to a method and apparatus for pigging feasibility analysis of Class I gas pipelines. Background Art

[0002] For Class I gas pipelines, it is crucial to systematically and comprehensively identify their potential risks, establish evaluation indicators and judgment systems, and quickly analyze the risks and feasibility of pipe cleaning operations, in order to guide on-site pipe cleaning operations in oil and gas fields and ensure the safety of natural gas gathering and transmission pipeline cleaning operations.

[0003] In the relevant technologies, a number of evaluation standards for the risks of pipe cleaning operations have been developed.

[0004] However, these evaluation standards only provide methods for risk assessment from certain aspects, but do not provide an assessment method for the feasibility of pigging the gas pipeline as a whole, so the reliability of the assessment is low. Summary of the invention

[0005] The present application provides a method and device for analyzing the feasibility of cleaning a Class I gas pipeline, which can provide an analysis method for the feasibility of cleaning the gas pipeline as a whole, thereby improving the reliability of the feasibility assessment of cleaning.

[0006] On the one hand, the present application provides a method for analyzing the feasibility of pigging a Class I gas pipeline, comprising:

[0007] Obtain the pipeline pressure, pipeline flow rate, pipeline inner diameter, pipeline outer diameter, additional equipment information loaded on the gas pipeline, pipeline sending and receiving tube size information, pipeline elbow specification information, pipeline tee specification information, emergency repair and plugging history operation information, pipeline type information, pipeline elevation data, and medium composition information of the gas transported by the pipeline;

[0008] Determine in sequence whether the following cleaning conditions are met: determine whether the pipeline pressure meets the preset pressure requirement, determine whether the inner diameter of the pipeline does not exceed the preset inner diameter requirement, determine whether the gas pipeline does not have a diameter change based on the inner diameter of the pipeline, determine whether the gas pipeline does not have equipment that hinders cleaning based on the additional equipment information, determine whether the size of the sending and receiving cylinder meets the preset size requirement information, determine whether the bend on the gas pipeline meets the preset bend specification requirement based on the bend specification information, and determine whether the tee on the gas pipeline meets the preset tee specification requirement based on the tee specification information and the outer diameter of the pipeline. , judging whether there are no double tees on the gas pipeline according to the tee specification information and the outer diameter of the pipeline, judging whether the historical operation of the gas pipeline meets the preset operation requirements according to the historical information of the emergency repair and plugging operation, judging whether the gas pipeline does not belong to the preset special pipeline type according to the pipeline type information, judging whether the relative height difference of the gas pipeline does not exceed the preset height difference according to the pipeline elevation data, judging whether the gas transported by the gas pipeline does not contain the preset special gas type according to the medium composition information, and judging whether the gas pipeline is not a low-pressure and low-flow pipeline according to the pipeline pressure and the pipeline flow rate

[0009] If all the above cleaning conditions are met, it is determined to clean the gas pipeline.

[0010] On the other hand, the present application provides a pigging feasibility analysis device for a Class I gas transmission pipeline, comprising: a memory and a processor, the memory being used to store an executable program;

[0011] The processor is used to read and execute the executable program to implement the above-mentioned pipeline cleaning feasibility analysis method for Class I gas pipelines.

[0012] Compared with the related art, the present application includes obtaining the gas pipeline to be cleaned, including pipeline information, additional equipment information loaded on the gas pipeline, size information of the sending and receiving tubes on the pipeline, specification information of the elbows, specification information of the tee, historical information of emergency repair and plugging operations, pipeline type information, pipeline elevation data, and medium composition information of the gas transported by the pipeline. According to the obtained information, it is judged whether the corresponding cleaning conditions are met, so as to determine whether to clean the pipeline. Therefore, by considering the various cleaning conditions that need to be met for cleaning, an analysis method for the feasibility of cleaning the gas pipeline as a whole is given, thereby improving the reliability of the feasibility assessment of cleaning.

[0013] Other features and advantages of the present application will be described in the following description, and partly become apparent from the description, or be understood by implementing the present application. Other advantages of the present application can be realized and obtained by the schemes described in the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The accompanying drawings are used to provide an understanding of the technical solution of the present application and constitute a part of the specification. Together with the embodiments of the present application, they are used to explain the technical solution of the present application and do not constitute a limitation on the technical solution of the present application.

[0015] Figure 1 A schematic diagram of a process flow of a method for analyzing the feasibility of pigging a Class I gas pipeline provided in an embodiment of the present application;

[0016] Figure 2a A schematic flow chart of another method for analyzing the feasibility of pigging a Class I gas pipeline provided in an embodiment of the present application;

[0017] Figure 2b A schematic flow chart of another method for analyzing the feasibility of pigging a Class I gas pipeline provided in an embodiment of the present application;

[0018] Figure 2c A schematic flow chart of another method for analyzing the feasibility of pigging a Class I gas pipeline provided in an embodiment of the present application;

[0019] Figure 3 A schematic diagram of a hydrate determination process provided in an embodiment of the present application;

[0020] Figure 4 A hydrate formation boundary map provided in an embodiment of the present application. DETAILED DESCRIPTION

[0021] The present application describes multiple embodiments, but the description is exemplary rather than restrictive, and it is obvious to those skilled in the art that there may be more embodiments and implementations within the scope of the embodiments described in the present application. Although many possible feature combinations are shown in the drawings and discussed in the specific embodiments, many other combinations of the disclosed features are also possible. Unless specifically limited, any feature or element of any embodiment may be used in combination with any other feature or element in any other embodiment, or may replace any other feature or element in any other embodiment.

[0022] The present application includes and contemplates combinations of features and elements known to those of ordinary skill in the art. The embodiments, features and elements disclosed in the present application may also be combined with any conventional features or elements to form a unique invention scheme defined by the claims. Any features or elements of any embodiment may also be combined with features or elements from other invention schemes to form another unique invention scheme defined by the claims. Therefore, it should be understood that any feature shown and / or discussed in the present application may be implemented individually or in any appropriate combination. Therefore, except for the limitations made according to the attached claims and their equivalents, the embodiments are not subject to other restrictions. In addition, various modifications and changes may be made within the scope of protection of the attached claims.

[0023] In addition, when describing representative embodiments, the specification may have presented the method and / or process as a specific sequence of steps. However, to the extent that the method or process does not rely on the specific order of the steps described herein, the method or process should not be limited to the steps of the specific order described. As will be understood by those of ordinary skill in the art, other sequences of steps are also possible. Therefore, the specific sequence of the steps set forth in the specification should not be interpreted as a limitation to the claims. In addition, the claims for the method and / or process should not be limited to the steps of performing them in the order written, and those skilled in the art can easily understand that these sequences can be changed and still remain within the spirit and scope of the embodiments of the present application.

[0024] The present application embodiment provides a method for analyzing the feasibility of pigging a Class I gas pipeline, such as Figure 1 As shown, including:

[0025] Step 101, obtaining the pipeline pressure, pipeline flow rate, pipeline inner diameter, pipeline outer diameter, additional equipment information loaded on the gas pipeline, pipeline sending and receiving tube size information, pipeline elbow specification information, pipeline tee specification information, emergency repair and plugging history operation information, pipeline type information, pipeline elevation data, and medium composition information of the gas transported by the pipeline;

[0026] Step 102, determine in sequence whether the following cleaning conditions are met: determine whether the pipeline pressure meets the preset pressure requirement, determine whether the inner diameter of the pipeline does not exceed the preset inner diameter requirement, determine whether the gas pipeline does not have a diameter change according to the inner diameter of the pipeline, determine whether the gas pipeline does not have equipment that hinders cleaning according to the additional equipment information, determine whether the size of the sending and receiving cylinder meets the preset size requirement information, determine whether the bend on the gas pipeline meets the preset bend specification requirements according to the bend specification information, and determine whether the tee on the gas pipeline meets the preset tee specification according to the tee specification information and the outer diameter of the pipeline Requirements: determine whether there are no double tees on the gas pipeline based on the tee specification information and the outer diameter of the pipeline; determine whether the historical operations of the gas pipeline meet the preset operation requirements based on the historical repair and plugging operation information; determine whether the gas pipeline does not belong to the preset special pipeline type based on the pipeline type information; determine whether the relative height difference of the gas pipeline does not exceed the preset height difference based on the pipeline elevation data; determine whether the gas transported by the gas pipeline does not contain the preset special gas type based on the medium composition information; determine whether the gas pipeline is not a low-pressure and low-flow pipeline based on the pipeline pressure and the pipeline flow rate;

[0027] Step 103: If all the above cleaning conditions are met, determine to clean the gas pipeline.

[0028] For example, when the pipeline wall thickness design meets the oil and gas pipeline wall thickness design requirements in 8.1.3 of the standard GB50350-2015 Oilfield Oil and Gas Gathering and Transportation Design Code and the strength coefficient selection requirements in Table 8.4.5, it will not affect pipe cleaning; when its design coefficient is greater than the design requirements, the inner diameter exceeds the standard.

[0029] Exemplarily, the preset operation requirements are set in accordance with the standard SY / T7033-2016 Technical Specifications for Emergency Repair of Failed Steel Oil and Gas Pipelines and the standard SY / T 6150 Technical Regulations for Sealing Steel Pipelines.

[0030] Exemplarily, pipeline type information includes: dirty gas source pipeline, wet gas pipeline. Among them, wet gas pipeline generally refers to natural gas pipeline that has not been dehydrated and condensate recovered, or contains condensable liquid hydrocarbons or free water, or the operating temperature is lower than its dew point temperature, and the liquid content under standard conditions is less than 5% (volume percentage).

[0031] Exemplarily, the preset height difference may be 200 m.

[0032] Exemplarily, the preset special gas type is H2S.

[0033] For example, a pipeline with a pressure of 2.5MPa≤pressure<4MPa or a converted natural gas flow rate lower than 1.0m / s is a low-pressure and low-flow pipeline.

[0034] With the proposal of the "dual carbon" goal, countries around the world are constantly developing a lower-carbon energy system and pursuing the goal of net zero emissions. Natural gas, as a clean and low-carbon energy, is becoming more and more popular. Energy transformation has become a basic strategy for my country's economic and energy development. The experience of countries and regions that have achieved carbon peak, such as the European Union, the United States, the United Kingdom, and Japan, has proved that natural gas can play an important role in energy transformation and the realization of the dual carbon goals. The vigorous development of natural gas will surely promote my country's energy transformation and the realization of the "dual carbon" goals. With the increasing domestic demand for natural gas, the natural gas gathering and transportation pipeline system is becoming larger and larger. Among them, pigging operations have become a powerful guarantee measure to ensure the efficiency of natural gas gathering and transportation pipelines, and play an important role in the daily operations of natural gas transmission pipelines. However, according to reports in recent years, due to the long time span of pipeline construction, significant changes in terrain fluctuations, and insufficient understanding of risk identification, production safety problems such as pig blocking, stagnation, and pipeline leakage still occur in actual pigging operations. For Class I gas pipelines, it is crucial to systematically and comprehensively identify their potential risks, establish evaluation indicators and judgment systems, and quickly analyze the risks and feasibility of pipe cleaning operations, in order to guide on-site pipe cleaning operations in oil and gas fields and ensure the safety of natural gas gathering and transmission pipeline cleaning operations.

[0035] The embodiment of the present application provides a method for analyzing the feasibility of cleaning a Class I gas pipeline, which obtains information about the gas pipeline to be cleaned, including pipeline information, information about additional equipment loaded on the gas pipeline, size information of receiving and sending tubes on the pipeline, specification information of elbows, specification information of tees, historical information of emergency repair and plugging operations, pipeline type information, pipeline elevation data, and medium composition information of the gas transported by the pipeline. It is determined whether corresponding cleaning conditions are met based on the obtained information, thereby determining whether to perform cleaning. Therefore, by considering various cleaning conditions that need to be met for cleaning, a method for analyzing the feasibility of cleaning the gas pipeline as a whole is given, thereby improving the reliability of the cleaning feasibility assessment.

[0036] In an exemplary embodiment, the pipeline pressure includes: pipeline operating pressure, and the step of determining whether the pipeline pressure meets a preset pressure requirement includes:

[0037] First, determine whether the pipeline operating pressure is greater than the maximum pressure difference between the start and end points of the pipeline; wherein the maximum pressure difference between the start and end points of the pipeline is calculated by adding the start pressure difference of the pig, the pressure difference between the current gas transmission pressure of the receiving station and the gas transmission pressure of the sending station, and the maximum liquid accumulation elevation pressure difference in the gas transmission pipeline;

[0038] Secondly, if the pipeline operating pressure is greater than the maximum pressure difference between the starting and ending points of the pipeline, it is determined that the pipeline pressure meets the preset pressure requirement.

[0039] For example, the pipeline operating pressure is greater than the maximum pressure difference between the starting and ending points of the pipeline, which can be expressed as the following expression: P 运行压力 >P 起终点最大压差 Among them, P 起终点最大压差 =P1+P2+P3. P1 is the start-up pressure difference of the pig, P2 is the current gas transmission pressure difference between the receiving and sending stations, and P3 is the maximum liquid accumulation height pressure difference in the pipeline.

[0040] In an exemplary embodiment, the pipeline inner diameter includes: a plurality of pipeline inner diameters, and judging whether the gas pipeline has no diameter change according to the pipeline inner diameter includes:

[0041] First, traverse and obtain multiple pipeline inner diameters, and obtain two pipeline inner diameters from the multiple pipeline inner diameters each time for comparison operation until the multiple pipeline inner diameters are traversed, and the comparison operation includes: determining whether the difference between the two obtained pipeline inner diameters is not greater than a preset threshold;

[0042] Secondly, if the difference between the two pipeline inner diameters obtained each time is not greater than the preset threshold, it is determined that there is no diameter change in the gas transmission pipeline.

[0043] Exemplarily, the preset threshold may be 2.5%.

[0044] In an exemplary embodiment, the device that hinders pigging includes: an insertable monitoring device. When the device that hinders pigging is the insertable monitoring device, judging that the gas pipeline has a device that hinders pigging according to the additional device information further includes:

[0045] First, obtaining disassembly information of the insertable monitoring device;

[0046] Secondly, if it is determined based on the obtained disassembly information that the insertable monitoring device is removable and all other cleaning conditions are met except that there is no equipment that hinders cleaning, it is determined that the gas pipeline can be cleaned.

[0047] Exemplarily, the insertable monitoring equipment includes: a corrosion coupon, a corrosion probe, and a chemical filling point.

[0048] In an exemplary embodiment, the size of the transmitting and receiving cylinder includes: the length and wall thickness of the transmitting and receiving cylinder, and the step of determining whether the size of the transmitting and receiving cylinder meets the preset size requirement information includes:

[0049] First, determine whether the length of the sending and receiving ball cylinder is greater than the preset length of the pig, and whether the wall thickness of the sending and receiving ball cylinder is greater than the preset thickness;

[0050] Secondly, when the length of the sending and receiving ball cylinder is greater than the preset length of the pig and the wall thickness of the sending and receiving ball cylinder is greater than the preset thickness, it is determined that the size of the sending and receiving ball cylinder meets the preset size requirement information.

[0051] Exemplarily, the preset pipe cleaners include: pipe cleaning balls, foam pipe cleaners, leather cup pipe cleaners, straight plate pipe cleaners, steel brush pipe cleaners, diameter measuring pipe cleaners, and magnetic pipe cleaners.

[0052] For example, the preset thickness can be set with reference to the requirements for sending and receiving ball cylinders in 4.1 of the standard GB / T 27699-2011 Technical Specification for Internal Inspection of Steel Pipelines.

[0053] In an exemplary embodiment, the pipe bend specification information includes: pipe elbow curvature and straight pipe section length, and judging whether the pipe bend on the gas pipeline meets the preset pipe bend specification requirements according to the pipe bend specification information includes:

[0054] First, determine whether the curvature of the pipe elbow is greater than a preset curvature radius, and whether the length of the straight pipe section between the elbows of every two adjacent pipe elbows is greater than the outer diameter of the pipe;

[0055] Secondly, when the curvature of the pipeline elbow is greater than the preset curvature radius and the length of the straight pipe section between the elbows of every two adjacent elbows is greater than the outer diameter of the pipeline, it is determined that the elbow on the gas transmission pipeline meets the preset elbow specification requirements.

[0056] For example, when the curvature of the pipe elbow is less than the preset curvature radius, a shrimp waist bend may exist, and the shrimp waist bend cannot be cleaned.

[0057] In an exemplary embodiment, the three-way specification information includes: the opening diameter of the three-way, and judging whether the three-way on the gas pipeline meets the preset three-way specification requirements according to the three-way specification information and the outer diameter of the pipeline includes:

[0058] First, determine whether the diameter of the opening tee is greater than a preset ratio of the outer diameter of the pipeline;

[0059] Secondly, if the diameter of the open hole tee is not greater than the preset ratio of the outer diameter of the pipeline, it is determined whether the tee on the gas transmission pipeline meets the preset tee specification requirements.

[0060] Exemplarily, the preset ratio may be 30%.

[0061] In an exemplary embodiment, judging whether the gas pipeline does not have double tees according to the tee specification information and the pipeline outer diameter includes:

[0062] First, determine whether the distance between the centers of any two adjacent tees is greater than 1.5D+(d1+d2) / 2; where D is the outer diameter of the pipe, and d1 and d2 are the opening diameters of the adjacent tees;

[0063] Secondly, if the distance between the centers of two adjacent tees is greater than 1.5D+(d1+d2) / 2, it is determined that there is no double tee on the gas pipeline.

[0064] In an exemplary embodiment, when it is determined that there are double tees on the gas pipeline according to the tee specification information and the pipeline outer diameter, the method further includes:

[0065] First, the spacing between the three connections is obtained;

[0066] Secondly, determine whether the pig length is not less than the sum of the double tee spacing and 1.25 times the inner diameter of the pipeline;

[0067] Finally, if the length of the pig is not less than the sum of the double tee spacing and 1.25 times the inner diameter of the pipeline, and all other pigging conditions are met except that there is no double tee on the gas pipeline, it is determined that the gas pipeline can be pigged.

[0068] In the relevant technologies, many standards on risk assessment have been formulated at home and abroad, but most of them are about the service safety and integrity management of gathering and transportation pipelines, such as API 1160, ASME B31.8S, GB / T 27512, GB / T 34346, etc. For pigging operations, although there are special pigging or internal inspection standards such as SY / T 6148-1995, SY / T6383-1999, SY / T 6597-2018, etc., the content is simple, and no systematic targeted evaluation standards and method recommendations are given. The guidance is poor and it is impossible to effectively guide on-site personnel on how to predict risks when carrying out pigging operations and what reasonable safety measures to formulate.

[0069] In response to the above problems, the feasibility analysis method for cleaning pipes in Class I gas pipelines provided in the embodiments of the present application, on the basis of identifying the risks of cleaning operations in Class I gas pipelines and targeted safety measures, clarifies the potential risks and influencing factors of each link of the cleaning operation of the gas pipeline, classifies each type of influencing factors, and extracts the key evaluation indicators corresponding to each influencing factor. On this basis, the various feasibility evaluation indicators are connected in series in the form of a flow chart, and annotations are made for each evaluation indicator and its judgment criteria to facilitate users to understand the use of the feasibility analysis method more intuitively and comprehensively. According to the annotations, if further calculations or further judgments are required, corresponding calculation cases, judgment ideas and judgment methods are also given.

[0070] For example, the flowchart used in the method for analyzing the feasibility of pigging a Class I gas pipeline provided in the embodiment of the present application can be as follows: Figure 2a , 2b and 2c, where Figure 2b for Figure 2aThe process after judging it as a wet gas pipeline, Figure 2c for Figure 2a After determining that the pipeline is a large drop pipeline, the feasibility analysis method for pigging a Class I gas pipeline provided in the embodiment of the present application includes:

[0071] Step 1: Collect basic data on gas pipelines

[0072] For Class I gas pipelines, basic information including pipeline size specifications, pipeline mileage and elevation data, pipe fittings along the line, valve information, monitoring equipment information, receiving and sending ball cylinder information, rotating ball cylinder information, pipeline operating parameters, pipeline medium composition, pipeline repair and maintenance records, etc. is collected.

[0073] Step 2: Analysis of the impact of pipelines and their ancillary facilities on pigging operations

[0074] (1) Determine whether the pipeline pressure meets the requirements. 运行压力 >P 起终点最大压差 Among them, P 起终点最大压差 =P1+P2+P3. P1 is the start-up pressure difference of the pig, P2 is the current gas transmission pressure difference between the receiving and sending stations, and P3 is the maximum liquid elevation pressure difference in the pipe. If the pressure does not meet the requirements, the pipe cannot be pigged.

[0075] (2) Determine whether the inner diameter of the pipeline exceeds the standard. When the pipeline wall thickness design meets the oil and gas pipeline wall thickness design requirements in 8.1.3 of the standard GB50350-2015 Oilfield Oil and Gas Gathering and Transportation Design Code and the strength coefficient selection requirements in Table 8.4.5, it does not affect the cleaning of the pipe; when its design coefficient is greater than the design requirement, the inner diameter exceeds the standard and a special demonstration is required. During the demonstration, the passability of different types of pigs is considered, the passability is calculated, and it is determined whether the pipe can be cleaned and the type of pig selected. The jurisdiction should be based on the different passabilities of different pigs (for example, the passability of polyurethane foam pigs is 50%-60%, and the passability of leather cup pigs is about 80%. The specific passability coefficient is provided by the pig manufacturer). Combined with the specific pipe diameter, the passability of the pig under special circumstances should be determined by simulation calculation or test methods. For smooth transition structural problems, software such as Ansys can be used for simulation to determine its passing capacity; for sudden structural problems such as external inserts and steps, it is recommended to conduct a pull test on pipes above DN200, and a direct water pressure test on small-diameter pipes of DN200 and below. On this basis, consider the risk of cleaning the pipe and whether emergency measures are in place to determine whether the pipe can be cleaned.

[0076] (3) Determine whether there is a diameter change. The so-called diameter change refers to a pipe section with a different diameter whose inner diameter deviation is ≥ 2.5%.

[0077] (4) Determine whether there are valves with non-full bore diameters on the cleaning line. If so, the pipe cannot be cleaned.

[0078] (5) Determine whether there are plug-in monitoring devices, such as corrosion hanging pieces, corrosion probes, and chemical filling points, excluding mechanical ball indicators. If there are, determine whether the depth can be adjusted or removed in advance based on the product introduction. If not, a special demonstration is required. During the special demonstration, the locality should determine the passability of the pig under special circumstances based on the different passing capacities of different pigs (for example, the passing capacity of polyurethane foam pigs is 50%-60%, and the passing capacity of leather cup pigs is about 80%. The specific passing capacity coefficient is provided by the pig manufacturer). Combined with the specific pipe diameter, the passability of the pig under special circumstances should be determined by simulation calculation or test methods. Among them, for smooth transition structural problems, software such as Ansys can be used for simulation to determine its passing capacity; for sudden structural problems such as external inserts and steps, it is recommended to conduct a pull test on pipes above DN200, and a direct water pressure test on small diameter pipes of DN200 and below. On this basis, consider the pigging risks and whether the emergency measures are in place to determine whether the pig can be cleaned.

[0079] (6) Determine whether the dimensions of the sending and receiving tube meet the product design requirements. Focus on whether the structural length of the sending and receiving tube can meet the requirements of the longest pig or detector, and whether the wall thickness of the small tube can meet the design requirements of the sending and receiving tube. For specific dimensional parameter requirements, please refer to the requirements for sending and receiving tubes in 4.1 of the standard GB / T 27699-2011 Technical Specifications for Internal Inspection of Steel Pipelines. If the requirements are not met, pigging is not allowed.

[0080] (7) Determine whether the elbow specifications meet the design requirements, whether there are elbows on the pigging pipeline, and whether the curvature radius of the pipe elbow can meet the requirements for the pig to pass smoothly. In addition, whether the length of the straight pipe section between adjacent elbows is greater than the outer diameter of the pipe. If there is an elbow or the curvature radius of the elbow cannot meet the requirements for the pig to pass smoothly, the pipe cannot be pigged.

[0081] (8) Determine whether the tee meets the requirements. The tee on the pigging pipeline line should meet the requirements of 4.2 of the standard GB / T27699-2011 Technical Specification for Internal Inspection of Steel Pipelines, that is, when the diameter of the opening of the tee is greater than 30% of the outer diameter of the pipeline, a stopper or baffle should be installed. For specific requirements, refer to 4.2.1 and Appendix A. The axial length of the opening area of ​​the casing tee should not be greater than the outer diameter of the pipeline. If the requirements are not met, the pipeline cannot be pigged.

[0082] (9) Determine whether there is a double tee. That is, the distance between the centers of two adjacent tees (tees with opening diameters greater than 30% of the outer diameter of the pipeline) is ≤1.5D+(d1+d2) / 2. D is the outer diameter of the pipeline, and d1 and d2 are the opening diameters of adjacent tees. If it exists, a special demonstration is required. During the special demonstration, the length of the pipe cleaner is required to be ≥ the distance between the double tees + 1.25 times the inner diameter of the pipeline; if it is less than, it is necessary to use Ansys software for modeling and calculation to comprehensively determine whether the pipeline can be cleaned and whether the selection of the pipe cleaner is feasible.

[0083] (10) Determine whether there are improper emergency repair and plugging operations. The so-called improper emergency repair and plugging methods refer to the failure to perform emergency repairs in accordance with the requirements of the standard SY / T7033-2016 Technical Specifications for Emergency Repair of Failed Steel Oil and Gas Pipelines and the standard SY / T6150 Technical Regulations for Steel Pipeline Sealing, and the presence of foreign objects inserted into the pipeline, improper return of materials during pressure sealing, and other problems that do not meet the requirements. If so, a special demonstration is required. During the special demonstration, the local authorities should determine the passability of the pipe cleaner under special circumstances based on the different passing capacities of different pipe cleaners (for example, the passing capacity of polyurethane foam pipe cleaners is 50%-60%, and that of leather cup pipe cleaners is about 80%. The specific passing capacity coefficient is provided by the pipe cleaner manufacturer). Combined with the specific pipe diameter, the passability of the pipe cleaner under special circumstances should be determined through simulation calculations or tests. For smooth transition structural problems, software such as Ansys can be used for simulation to determine its passing capacity; for sudden structural problems such as external inserts and steps, it is recommended to conduct a pull test on pipes above DN200, and a direct water pressure test on small-diameter pipes of DN200 and below. On this basis, consider the risk of cleaning the pipe and whether emergency measures are in place to determine whether the pipe can be cleaned.

[0084] (11) Determine whether it is a dirty gas source pipeline. If it is a dirty gas source pipeline, a special demonstration is required. During the special demonstration, it is necessary to combine the operation time of the pipeline and whether there is an internal coating to make a judgment. If the service time is 3 years or more, it should be considered that there are a lot of impurities and liquid accumulation. It is recommended to formulate a pipe cleaning plan based on specific information such as pipeline specifications, operating conditions, crossing conditions and supporting facilities. Avoid using a pipe cleaner with a steel brush when there is an internal coating.

[0085] (12) Determine whether it is a wet gas pipeline. A wet gas pipeline generally refers to a natural gas pipeline that has not been dehydrated and has not been condensed and recovered, or a natural gas pipeline that contains condensable liquid hydrocarbons or free water, or an operating temperature lower than its dew point temperature, and a liquid content of less than 5% (volume percentage) under standard conditions. If it is a wet gas pipeline, it is necessary to determine whether it will freeze, whether hydrates will be formed, whether slug flow will occur, whether it will cause the steel skeleton of the pig to break, whether it will cause the non-metallic accessories of the pig to age, and whether the instantaneous amount of material removed will exceed the processing capacity of the downstream equipment. The specific determination method is as follows:

[0086] a. Determination of freezing risk. If there is an exposed section of the pipeline, the exposed section has no insulation layer, and the ambient temperature of the exposed location is lower than the freezing point of the condensed water precipitated from the natural gas, there is a risk of freezing. If there is a risk of freezing, it is necessary to determine whether the site can formulate conditions such as increasing the operating temperature of the pipeline, equipping boiler trucks and heating belt heating devices, etc., to achieve heating and unblocking of the frozen pipe section. If not, the pipe cannot be cleaned.

[0087] b. Determination of hydrate risk. Specifically, the determination process of hydrates can be shown in 3. In practice, it can be based on Figure 3 The judgment process and on-site management experience, combined with Figure 4 The hydrate formation boundary diagram shown in Figure 2 can be used to determine whether hydrates will form inside the pipeline. Figure 3 The analysis process and hydrate formation boundary diagram in the paper can be used to determine whether hydrates will be formed. If there is a risk of hydrate formation, it is necessary to confirm whether the site can meet the conditions for formulating measures such as injecting methanol or other hydrate inhibitors into the pipeline before pigging. If not, pigging is not allowed.

[0088] c. The risk of slugging can be determined by calculating the flow state of the medium in the pipeline based on the semi-empirical multiphase flow prediction model or multiphase flow calculation software such as Pipephase, Pipesys, Pipeflo, Pipesim, Tacite, OLGA, etc., to determine whether there is slugging. If there is slugging, it is necessary to determine whether the instantaneous discharge volume exceeds the processing capacity of the downstream equipment.

[0089] d. Once the downstream equipment's processing capacity is exceeded, are there conditions to take countermeasures such as branch lines and temporary processing facilities? If not, pigging is not allowed.

[0090] e. The risk of cracking of the steel skeleton of the pipe cleaner can be determined by referring to the requirements for the crack resistance of carbon steel and low alloy steel in the standard ISO 15156-2, and evaluating whether the metal skeleton of the pipe cleaner in use has the risk of sulfide stress corrosion cracking from the perspectives of hardness, temperature, in-situ pH value, H2S partial pressure, etc. If the steel skeleton of the pipe cleaner will crack, the pipe cannot be cleaned or the type of pipe cleaner should be changed.

[0091] f. Determination of the aging risk of non-metallic materials of pigs, when P CO2 ≥1.5MPa or P H2S Under a partial pressure of ≥1.2MPa, the anti-swelling and anti-sulfurization performance of rubber-like non-metallic materials in the medium should be evaluated. If it will cause aging of the non-metallic materials of the pig, the pig cannot be cleaned or the material type of the accessories must be replaced, and an anti-aging performance verification test must be carried out.

[0092] (13) Determine whether it is a pipeline with a large drop. Generally speaking, a pipeline with a relative height difference of more than 200m along the pipeline is a pipeline with a large drop. If it is a pipeline with a large drop, it is necessary to determine whether there is a risk of liquid accumulation, ice formation, and hydrate formation. The specific analysis method is as follows:

[0093] a. First, determine whether there is a risk of liquid accumulation. To this end, refer to the critical inclination calculation method recommended in standard GB / T34349-2017 to obtain the critical inclination, and compare the elevation data in the pipeline to determine whether there is liquid accumulation.

[0094] b. Once liquid accumulates, it is necessary to further determine whether there is a risk of freezing in the on-site pipeline. If there is an exposed section of the pipeline, the exposed section has no insulation layer, and the ambient temperature of the exposed location is lower than the freezing point of the condensed water precipitated from the natural gas, there is a risk of freezing. If there is a risk of freezing, it is necessary to determine whether the site can formulate conditions such as increasing the operating temperature of the pipeline, equipping boiler trucks and heating belt heating devices, etc., to achieve heating and unblocking of the frozen pipe section. If not, the pipe cannot be cleaned.

[0095] c. Determine whether there is a risk of hydrate formation. Based on the determination process in Figure 2 and on-site management experience, it can be determined whether hydrates will form inside the pipeline. If there is a risk of hydrate formation, it is necessary to confirm whether the site can meet the conditions for formulating measures such as injecting methanol or other hydrate inhibitors into the pipeline before cleaning. If not, the pipeline cannot be cleaned.

[0096] (14) Determine whether H2S is present. If the medium contains H2S, it should be confirmed whether the site has the conditions to take safety measures such as filling the ball collecting cylinder with nitrogen or water in advance. If not, the pipe cannot be cleaned.

[0097] (15) Determine whether it is a low-pressure, low-flow pipeline. Generally speaking, a pipeline with a pressure of 2.5MPa≤<4MPa or a converted natural gas flow rate of less than 1.0m / s is a low-pressure, low-flow pipeline. If it is a low-pressure, low-flow pipeline, it is necessary to confirm whether the site has the conditions to formulate safety measures such as reasonable selection of pigs (reducing pig size, reducing pig weight, installing wear-resistant nails, etc.), pig tracking at elbows, monitoring of front and rear pressure difference changes, and equipping with foam rescue pigs. If not, the pipeline cannot be cleaned.

[0098] If the results of the above steps meet the requirements, cleaning can be carried out. However, corresponding safety measures need to be formulated to address potential risks.

[0099] In the above feasibility analysis method, the annotations of some processes involved are shown in Table 1.

[0100] Table 1

[0101]

[0102]

[0103]

[0104] The feasibility analysis method for pigging a Class I gas pipeline provided in the embodiment of the present application fills the gap in this field and has the following beneficial effects:

[0105] When using a pipe cleaner for pipe cleaning, potential risks and their influencing factors can be identified and determined, and it can be determined whether the pipe can be cleaned and the necessary supporting safety measures. At the same time, the reasons why special demonstration is needed and why pipe cleaning is not possible are given; and the complexity of the pipe cleaning operation and the convenience of analysis and evaluation by on-site personnel are fully considered, and the basis for judgment of each step is given to the greatest extent. If special demonstration is needed, the ideas of special demonstration are given; if in-depth analysis and judgment are needed, the ideas of analysis, calculation and experiment are given. This method objectively and accurately analyzes the feasibility of pipe cleaning of Class I gas pipelines. The method is simple, convenient, easy to operate on site, and can quickly give feasibility analysis results.

[0106] The feasibility evaluation results obtained by the pigging feasibility analysis method for Class I gas pipelines provided in the application example are shown in Table 2.

[0107] Table 2

[0108] Evaluation results Remark Not piggable Reasons for non-purge Special demonstration Contents that require special verification Can clean pipes Necessary safety measures

[0109] Among them, when the pipe cannot be cleaned, the specific reasons why it cannot be cleaned need to be clarified to facilitate subsequent maintenance and renovation; when a special demonstration is required, the content of the special demonstration should be clarified, and a special demonstration meeting should be held to combine the opinions of experts in various fields to comprehensively determine the feasibility of cleaning the pipe; when the pipe can be cleaned, the necessary safety measures should be determined based on the analysis process to ensure the smooth implementation of the cleaning.

[0110] When the production process changes significantly or the pipeline undergoes major maintenance and renovation, or there is a long interval without cleaning, it is necessary to conduct a new cleaning feasibility analysis.

[0111] The feasibility analysis method for cleaning pipes for Class I gas transmission pipelines provided in the application embodiment can identify and determine the risks of cleaning pipes based on the current status of the pipelines, clarify the potential risks in the cleaning operation and the size of their impact on cleaning pipes, so as to provide feasibility analysis results of whether the pipes cannot be cleaned, special demonstrations are required, or the pipes can be cleaned. The advantage of this method is that it fully considers the complexity and potential risks of the cleaning operation, simplifies the feasibility analysis procedure, and can quickly provide analysis results on the one hand, and can also provide corresponding reasons on the other hand. Through this method, the feasibility analysis results are divided into three types (cannot be cleaned, special demonstrations, and can be cleaned), which can objectively and accurately analyze the risks and feasibility of cleaning pipes, and can be used to guide on-site cleaning operations.

[0112] The embodiments of the present application also provide the following implementation cases to illustrate the provided feasibility analysis method for cleaning a Class I gas pipeline.

[0113] Implementation Case 1

[0114] 1) Collection and organization of basic information

[0115] According to the feasibility analysis requirements, pipeline ownership information (ownership unit), basic information (pipeline specifications, mileage, elevation, dimensions and specifications of key ancillary and monitoring facilities), pipeline operation parameters (temperature, pressure, flow, etc.), pipeline medium composition and physicochemical performance parameters (medium components, water content, CO2 / H2S content, solid particle size and content, etc.), and other parameters (repair and maintenance information, pigging and internal inspection information, etc.) are collected.

[0116] The collected information is organized and the specific information is shown in the following table.

[0117] Table 3

[0118]

[0119]

[0120] 2) Processing of key parameters

[0121] According to the feasibility analysis method of gas pipeline, the key parameters related to the result analysis are sorted out as shown in the following table.

[0122] Table 4

[0123]

[0124] 3) Feasibility analysis results

[0125] According to the key parameters in Table 4, the key criteria of the pipeline are determined according to the feasibility analysis method process and notes, and the results are shown in Table 5. According to the determination results in Table 4, the feasibility analysis results can be obtained, that is, the pipeline can be pigged.

[0126] Table 5

[0127]

[0128] Implementation Case 2

[0129] 1) Collection and organization of basic information

[0130] According to the feasibility analysis requirements, pipeline data is collected and the collected information is organized. The specific information of the gas pipeline in Implementation Case 2 is shown in the following table.

[0131] Table 6

[0132]

[0133]

[0134] 2) Processing of key parameters

[0135] According to the feasibility analysis method of gas pipeline, the key parameters related to the result analysis are sorted out as shown in the following table.

[0136] Table 7

[0137]

[0138]

[0139] 3) Feasibility analysis results

[0140] According to the key parameters in Table 7, the key criteria of the pipeline are determined according to the feasibility analysis method process and notes, and the results are shown in Table 8. According to the results in Table 8, due to the existence of improper emergency maintenance operation records, special demonstration is required.

[0141] Table 8

[0142]

[0143] Implementation Case 3

[0144] 1) Collection and organization of basic information

[0145] According to the feasibility analysis requirements, pipeline data is collected and the collected information is organized. The specific information of the gas pipeline in Implementation Case 3 is shown in Table 9.

[0146] Table 9

[0147]

[0148]

[0149] 2) Processing of key parameters

[0150] According to the feasibility analysis method of gas pipeline, the key parameters related to the result analysis are sorted out, as shown in Table 10.

[0151] Table 10

[0152]

[0153]

[0154] 3) Feasibility analysis results

[0155] According to the key parameters in Table 10, the key criteria of the pipeline are determined according to the feasibility analysis method process and notes, and the results are shown in Table 11. According to the judgment results in Table 11, since the tee is not equipped with a retaining bar, it does not meet the requirements of the tee pigging design and cannot be pigged.

[0156] Table 11

[0157]

[0158] The embodiment of the present application also provides a pigging feasibility analysis device for a Class I gas transmission pipeline, comprising: a memory and a processor, wherein the memory is used to store an executable program;

[0159] The processor is used to read and execute the executable program to implement the pigging feasibility analysis for Class I gas pipelines described in any of the above embodiments.

[0160] The embodiment of the present application provides a pipe cleaning feasibility analysis device for a Class I gas pipeline, which obtains the gas pipeline to be cleaned, including pipeline information, additional equipment information loaded on the gas pipeline, size information of the transmitting and receiving tubes on the pipeline, specification information of the elbows, specification information of the tees, historical information of emergency repair and plugging operations, pipeline type information, pipeline elevation data, and medium composition information of the gas transported by the pipeline. It determines whether the corresponding pipe cleaning conditions are met based on the obtained information, thereby determining whether to perform pipe cleaning. Therefore, by considering the various pipe cleaning conditions that need to be met for pipe cleaning, a pipe cleaning feasibility analysis method is given for the gas pipeline as a whole, thereby improving the reliability of the pipe cleaning feasibility assessment.

[0161] It will be appreciated by those skilled in the art that all or some of the steps, systems, and functional modules / units in the disclosed methods above may be implemented as software, firmware, hardware, and appropriate combinations thereof. In hardware implementations, the division between the functional modules / units mentioned in the above description does not necessarily correspond to the division of physical elements; for example, a physical element may have multiple functions, or a function or step may be performed by several physical elements in cooperation. Some or all elements may be implemented as software executed by a processor, such as a digital signal processor or a microprocessor, or implemented as hardware, or implemented as an integrated circuit, such as an application-specific integrated circuit. Such software may be distributed on a computer-readable medium, which may include a computer storage medium (or non-transitory medium) and a communication medium (or temporary medium). As known to those skilled in the art, the term computer storage medium includes volatile and non-volatile, removable and non-removable media implemented in any method or technology for storing information (such as computer-readable instructions, data structures, program modules, or other data). Computer storage media include, but are not limited to, RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, digital versatile disks (DVD) or other optical disk storage, magnetic cassettes, magnetic tapes, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to store the desired information and can be accessed by a computer. In addition, it is well known to those of ordinary skill in the art that communication media typically contain computer-readable instructions, data structures, program modules, or other data in a modulated data signal such as a carrier wave or other transport mechanism, and may include any information delivery media.

Claims

1. A method for pigging feasibility analysis of a Class I gas pipeline, characterized in that: include: Obtain the pipeline pressure, pipeline flow rate, pipeline inner diameter, pipeline outer diameter, additional equipment information loaded on the gas pipeline, pipeline sending and receiving tube size information, pipeline elbow specification information, pipeline tee specification information, emergency repair and plugging history operation information, pipeline type information, pipeline elevation data, and medium composition information of the gas transported by the pipeline; Determine in sequence whether the following cleaning conditions are met: determine whether the pipeline pressure meets the preset pressure requirement, determine whether the inner diameter of the pipeline does not exceed the preset inner diameter requirement, determine whether the gas pipeline does not have a diameter change according to the inner diameter of the pipeline, determine whether the gas pipeline does not have equipment that hinders cleaning according to the additional equipment information, determine whether the size of the sending and receiving cylinder meets the preset size requirement information, determine whether the bend on the gas pipeline meets the preset bend specification requirement according to the bend specification information, and determine whether the tee on the gas pipeline meets the preset tee specification requirement according to the tee specification information and the outer diameter of the pipeline. Determine whether there are no double tees on the gas pipeline based on the tee specification information and the outer diameter of the pipeline; determine whether the historical operations of the gas pipeline meet the preset operation requirements based on the historical repair and plugging operation information; determine whether the gas pipeline does not belong to the preset special pipeline type based on the pipeline type information; determine whether the relative height difference of the gas pipeline does not exceed the preset height difference based on the pipeline elevation data; determine whether the gas transported by the gas pipeline does not contain the preset special gas type based on the medium composition information; determine whether the gas pipeline is not a low-pressure and low-flow pipeline based on the pipeline pressure and the pipeline flow rate; If all the above cleaning conditions are met, it is determined to clean the gas pipeline.

2. The method according to claim 1, characterized in that The pipeline pressure includes: pipeline operating pressure, and the determination of whether the pipeline pressure meets the preset pressure requirement includes: Determine whether the pipeline operating pressure is greater than the maximum pressure difference between the starting and ending points of the pipeline; wherein the maximum pressure difference between the starting and ending points of the pipeline is calculated by adding the starting pressure difference of the pig, the pressure difference between the current gas transmission pressure of the receiving station and the gas transmission pressure of the sending station, and the maximum liquid accumulation elevation pressure difference in the gas transmission pipeline; If the pipeline operating pressure is greater than the maximum pressure difference between the starting and ending points of the pipeline, it is determined that the pipeline pressure meets the preset pressure requirement.

3. The method according to claim 1, characterized in that The pipeline inner diameter includes: a plurality of pipeline inner diameters, and judging whether the gas pipeline has no diameter change according to the pipeline inner diameter includes: Traversing and obtaining multiple pipeline inner diameters, obtaining two pipeline inner diameters from the multiple pipeline inner diameters each time for comparison operation, until the multiple pipeline inner diameters are traversed, the comparison operation includes: determining whether the difference between the two obtained pipeline inner diameters is not greater than a preset threshold; If the difference between the two pipeline inner diameters obtained each time is not greater than the preset threshold, it is determined that there is no diameter change in the gas transmission pipeline.

4. The method according to claim 1, characterized in that: The device that hinders pigging includes: an insertable monitoring device. When the device that hinders pigging is the insertable monitoring device, judging that the gas pipeline has the device that hinders pigging according to the additional device information further includes: Obtaining disassembly information of the insertable monitoring device; If it is determined according to the obtained disassembly information that the insertable monitoring device is removable, and all other cleaning conditions are met except that there is no equipment that hinders cleaning, it is determined that the gas pipeline can be cleaned.

5. The method according to claim 1, characterized in that The size of the transmitting and receiving cylinder includes: the length and wall thickness of the transmitting and receiving cylinder, and the information of judging whether the size of the transmitting and receiving cylinder meets the preset size requirement includes: Determine whether the length of the sending and receiving ball cylinder is greater than the preset length of the pig, and whether the wall thickness of the sending and receiving ball cylinder is greater than the preset thickness; When the length of the sending and receiving ball cylinder is greater than the preset length of the pig, and the wall thickness of the sending and receiving ball cylinder is greater than the preset thickness, it is determined that the size of the sending and receiving ball cylinder meets the preset size requirement information.

6. The method according to claim 1, characterized in that The pipe bend specification information includes: pipe elbow curvature and straight pipe length. The method of judging whether the pipe bend on the gas pipeline meets the preset pipe bend specification requirements according to the pipe bend specification information includes: Determine whether the curvature of the pipe elbow is greater than a preset curvature radius, and whether the length of the straight pipe section between the elbows of every two adjacent pipe elbows is greater than the outer diameter of the pipe; When the curvature of the pipeline elbow is greater than the preset curvature radius and the length of the straight pipe section between the elbows of every two adjacent elbows is greater than the outer diameter of the pipeline, it is determined that the elbow on the gas transmission pipeline meets the preset elbow specification requirements.

7. The method according to claim 1, characterized in that The three-way specification information includes: the opening diameter of the three-way, and judging whether the three-way on the gas pipeline meets the preset three-way specification requirements according to the three-way specification information and the outer diameter of the pipeline includes: Determining whether the diameter of the opening tee is greater than a preset ratio of the outer diameter of the pipeline; If the diameter of the open hole tee is not greater than the preset ratio of the outer diameter of the pipeline, it is determined whether the tee on the gas pipeline meets the preset tee specification requirements.

8. The method according to claim 1, characterized in that The determining whether the gas pipeline does not have double tees according to the tee specification information and the pipeline outer diameter includes: Determine whether the distance between the centers of any two adjacent tees is greater than 1.5D+(d1+d2) / 2; wherein D is the outer diameter of the pipe, and d1 and d2 are the opening diameters of the adjacent tees; If the distance between the centers of two adjacent tees is greater than 1.5D+(d1+d2) / 2, it is determined that there is no double tee on the gas pipeline.

9. The method according to claim 7, characterized in that: When it is determined that there are double tees on the gas pipeline according to the tee specification information and the pipeline outer diameter, the method further includes: Obtaining the spacing between the three links; Determine whether the pig length is not less than the sum of the double tee spacing and 1.25 times the inner diameter of the pipeline; If the length of the pig is not less than the sum of the double tee spacing and 1.25 times the inner diameter of the pipeline, and all other pigging conditions are met except that there is no double tee on the gas pipeline, it is determined that the gas pipeline can be pigged.

10. A pigging feasibility analysis device for a Class I gas pipeline, comprising: A memory and a processor, wherein the memory is used to store an executable program; The processor is used to read and execute the executable program to implement the pigging feasibility analysis method for Class I gas pipelines as described in any one of claims 1-9.

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