CN112800699A - Early warning method for simulating hydrate blockage of submarine gas pipeline transportation - Google Patents

Early warning method for simulating hydrate blockage of submarine gas pipeline transportation Download PDF

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CN112800699A
CN112800699A CN202110186302.2A CN202110186302A CN112800699A CN 112800699 A CN112800699 A CN 112800699A CN 202110186302 A CN202110186302 A CN 202110186302A CN 112800699 A CN112800699 A CN 112800699A
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王大勇
李孟昕
陈天宇
沙婕
宋永臣
王启林
贾靖冬
王子明
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Dalian University of Technology
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Abstract

An early warning method for simulating the transportation of a hydrate-blocked submarine gas pipeline belongs to the technical field of pipeline flow safety. The method simulates physical and chemical changes in the flowing process of the submarine pipeline, reveals the influence of the generation, transportation and deposition of hydrates in the submarine pipeline on the flowing safety of the pipeline, considers the hydrates in the flowing safety of the pipeline so as to provide reference for judging the blockage of the submarine pipeline and better provide technical support for the transportation of the gas pipeline in the sea area, and has practical and scientific significance. The method provided by the invention can be used for preliminarily predicting the generation of the hydrate of the submarine pipeline, providing data and evaluating the flow safety problem of submarine oil and gas transportation, realizing low cost, wide coverage and high efficiency, and improving the safety of submarine natural gas transportation.

Description

Early warning method for simulating hydrate blockage of submarine gas pipeline transportation
Technical Field
The invention relates to an early warning method for simulating hydrate blockage of submarine gas pipeline transportation, and belongs to the technical field of early warning of oil and gas pipelines.
Background
The natural gas hydrate is a cage-type compound, and is a solid compound formed by methane gas and water under the conditions of low temperature and high pressure. In the process of oil and gas exploitation and transportation, particularly, the generation of hydrates is more facilitated under the low temperature and high pressure in a deep water environment, however, the situation that the natural gas hydrates block the pipelines cannot be treated on site, the oil and gas exploitation efficiency can be seriously affected, and therefore, the research on the flow safety problem caused by hydrate blockage in the pipelines is a basic guarantee for solving the problems.
The current flow safety evaluation cannot perform integral observation on the blocking state of the natural gas hydrate in a pipeline, cannot obtain a real-time image of the blocking process of the generation of the hydrate, and cannot provide basic data for solving the flow safety problem in the process of transporting a submarine oil and gas pipeline. Therefore, how to predict the blocking risk of the regional submarine pipeline and convert the passive monitoring and processing of the submarine pipeline flow into active prediction and response are problems to be solved in the field.
Disclosure of Invention
The invention aims to provide a warning method for simulating hydrate blockage of submarine gas pipeline transportation aiming at the defects of the prior art. The method realizes the prediction of the blocking risk of the regional submarine oil and gas pipeline, has low cost, wide coverage and high treatment efficiency, and improves the overall safety of submarine pipeline flow.
In order to achieve the purpose, the invention adopts the following technical scheme: an early warning method for simulating hydrate-plugged submarine gas pipeline transportation, comprising the following steps:
s1, collecting basic information of all pipelines in the area, wherein the basic information comprises the inner diameter of the pipeline, the outer diameter of the pipeline, the length of the pipeline, the material of the pipeline, the ambient temperature, the temperature of the fluid and the pressure of a fluid inlet; obtaining a hydrate equilibrium triple point through input parameters, fluid pressure and fluid temperature at an inlet of a seabed oil and gas pipeline;
s2, on the basis of physical conditions, the hydrate generation amount cannot be a negative value, so that if the supercooling degree obtained in the supercooling degree module is a negative value or equal to 0, no hydrate is generated; if the supercooling degree is more than 0, determining that phase change occurs in the pipeline and hydrate is generated;
ΔTsub＝teq-t
wherein, Delta TsubRepresented by the degree of supercooling, t, of the control systemeqRepresented as the equilibrium temperature of the control system, and t is represented as the temperature of the control system;
obtaining the total hydrate generation amount of the system based on the supercooling degree and the gas-water interface area of the submarine pipeline system;
Figure BDA0002943227440000021
wherein the content of the first and second substances,
Figure BDA0002943227440000022
denotes the amount of hydrate formed per unit time, FkRepresenting the formation coefficient of hydrates, whose value is related to the flow pattern of the fluid in the submarine pipeline, C1、C2Is a constant number, MgRepresents the average molar mass of the system fluid,
Figure BDA0002943227440000023
representing the average density of the system fluid, A representing the gas-water interface area in the control system;
A＝Adrop+Afilm
wherein，AdropRepresenting the gas-water cross-sectional area of the droplets dispersed in the gas phase in the system, AfilmRepresenting the gas-water interface area of a liquid film on the pipe wall of the submarine pipeline in the system;
calculating the generation amount of the hydrate through a first-order kinetic formula of hydrate generation based on the supercooling degree of the pipeline system to obtain the variation trend of the hydraulic diameter along with the temperature and the pressure;
Figure BDA0002943227440000024
Figure BDA0002943227440000025
represents a temperature change per unit length, i.e., a temperature gradient; beta is aJTRepresents the char water coefficient, U represents the integrated heat transfer coefficient between the fluid and the environment in the control system, T represents the temperature of the fluid in the control system, and T represents the temperature of the fluid in the control systemextRepresenting ambient temperature,. DELTA.H representing hydrate formation being exothermic, QmRepresenting the flow rate of fluid in the pipe per unit time, pmRepresenting the average density of the mixed fluid in the control system, CpmRepresenting the heat capacity of the mixed fluid in the control system;
Qm＝Qg+Ql
Qgrepresenting the flow rate of gas per unit time in the control system, QlRepresenting the flow rate of liquid per unit time in the control system;
s3, evaluating the flow safety of the whole pipeline system by adopting the pressure difference between the fluid inlet and the fluid outlet; the pressure difference is increased when the hydrate is generated and the hydraulic diameter is reduced;
Figure BDA0002943227440000031
wherein the content of the first and second substances,
Figure BDA0002943227440000032
representing pressure changes per unit length in the line, f representingCoefficient of friction, pnsRepresenting the density of the fluid in the control system without sliding friction, DhRepresenting hydraulic diameter in a subsea pipeline, vmRepresenting the flow rate of the mixed fluid in the control system;
simulating by a backward iteration method, controlling the pressure and temperature change in the body and the hydraulic diameter change caused by hydrate to cause the inlet and outlet pressure difference change of the submarine pipeline, and comprehensively judging the safety of the pipeline by the pressure difference change; when the hydraulic diameter of the submarine pipeline is too small, the system judges that the pressure difference between the inlet and the outlet of the pipeline reaches a preset value, the submarine pipeline is determined to be blocked, the state of the early warning system is judged, early warning information is prompted to platform equipment, or pipeline safety operation is carried out, including pipeline heating or pipeline cleaning. The pipeline transportation early warning system comprises an acquisition module, a hydrate generation module, a hydraulic diameter module, a heat transfer module, a pressure module and an early warning module.
An acquisition module: collecting basic information of all pipelines in the region, wherein the basic information comprises pipeline inner diameter, pipeline outer diameter, pipeline length, pipeline material, environment temperature, fluid flow, fluid inlet pressure and water content ratio;
a hydrate generation module: obtaining the total hydrate generation amount of the system by utilizing a first-order kinetic equation of hydrate generation based on the supercooling degree and the gas-water interface area of the submarine pipeline system; on the basis of physical conditions, the generation amount of the hydrate cannot be a negative value, so that the condition that no hydrate is generated if the obtained supercooling degree in the supercooling degree module is a negative value or equal to 0 is limited, the condition that the phase change occurs in a pipeline if the supercooling degree is greater than 0 is considered, and the heat transfer and pressure distribution are violently changed due to the phase change;
a hydraulic diameter module: the hydrate can be settled and attached to the pipe wall due to gravity and flow factors, so that the flow diameter of the fluid is reduced, and the quantity describing the flow diameter is called hydraulic diameter; the hydraulic diameter is the limit to the flow velocity of the fluid in the system under the condition that the flow of the submarine pipeline is constant;
a heat transfer module: heat transfer includes the joule-thomson effect, the interaction of the environment, and the heat generated by phase changes. Joule-thomson effect refers to the temperature change of the fluid in the pipe flow due to a drastic change in pressure; the environment interaction means that the temperature of fluid transported by a submarine pipeline is usually higher than the environment temperature, so that the temperature of the fluid in the pipeline is continuously reduced to a hydrate stable region in the process of submarine long-distance transportation; the temperature change caused by phase change is easy to generate the hydrate under the conditions of high pressure and low temperature, and the environment of the submarine pipeline is just the hydrate generation interval, and the reaction is an exothermic reaction that gas molecules react with liquid water molecules to become solid.
A pressure module: in field measurement, due to the particularity of a submarine pipeline system, data capable of being directly detected is limited, most relevant values are obtained in an approximate range through monitoring pressure changes through an empirical formula, and therefore the pressure changes of a fluid inlet and a fluid outlet have great significance for evaluating the flow safety in the whole pipeline system. The pressure drop is increased due to hydrate generation, hydraulic diameter reduction and the like, the viscosity of the fluid is increased due to the hydrate generation, and the system needs larger energy to drive the fluid to advance; the hydraulic diameter of the pipeline is reduced due to adsorption and sedimentation of the hydrate, which has great influence on pressure drop, and in addition, the pressure difference between an inlet and an outlet is also increased due to the loss of gas and liquid caused by the generation of the hydrate;
the early warning module: when the system judges that the pressure drop before and after reaches a preset value, an early warning is provided for an operation platform, or related pipeline safety operation is carried out, and a pipeline is heated or cleaned.
The method is simulated by a backward iteration method, the pressure and temperature change in a control body and the hydraulic diameter change of a hydrate can be known through the formula, and the safety of the pipeline is comprehensively judged according to the parameters.
The gas-water interface area is introduced through the first-order hydrate generation formula, so that liquid drops dispersed in a gas phase and a liquid film on the pipe wall of the submarine pipeline can be considered at the same time, the generation amount of the hydrate in the pipeline can be predicted more accurately, and the blockage of the hydrate in the pipeline can be judged more accurately.
Compared with the prior art, the invention has the following advantages:
the method and the device have the advantages that the blocking risk of the regional submarine oil and gas pipeline is predicted, the problem that the flow safety of the pipeline is predicted by single pressure in the prior art is solved, and a scheme is provided for predicting and evaluating the flow safety risk of the regional submarine oil and gas pipeline in the prior art.
According to field data and experimental observation, the method can more accurately predict the blocking time and the blocking position of the submarine oil and gas pipeline by considering various channels for generating hydrate films, and finally obviously improves the whole flowing safety prediction of the submarine pipeline.
The method is adopted for evaluating the submarine oil and gas pipeline in the region, the overall level of the submarine pipeline in the region can be predicted, each section of submarine pipeline with different risks can be accurately processed, the transport risk of the submarine pipeline is reduced, and passive monitoring and processing on the flow safety of the submarine oil and gas pipeline are converted into active prediction and response.
The system comprises hydrate generation, transportation and sedimentation processes; each process is described by an associated governing equation, and the governing equation of the involved physicochemical change can be encoded and put into a commercial simulator to run. The method simulates physical and chemical changes in the flowing process of a real conveying pipeline, reveals the formation, sedimentation mode and flow blockage condition of the hydrate in the submarine pipeline, considers the hydrate effect in the flowing safety of the pipeline so as to provide reference for the safety scheme design of the submarine pipeline and better provide technical support for sea hydrate exploitation, and has practical and scientific significance.
Drawings
FIG. 1 is a block diagram of a subsea hydrocarbon pipeline transportation early warning system based on hydrate effects.
FIG. 2 is a flow chart of a subsea hydrocarbon pipeline transportation early warning method based on hydrate effect.
Detailed Description
Fig. 1 shows a submarine oil and gas pipeline transportation early warning system based on hydrate effect, which comprises a collection module, a hydrate generation module, a hydraulic diameter module, a heat transfer module, a pressure module and an early warning module.
An acquisition module: and collecting basic information of all pipelines in the region, wherein the basic information comprises the inner diameter of the pipeline, the outer diameter of the pipeline, the length of the pipeline, the material of the pipeline, the ambient temperature, the temperature of the fluid, the flow rate of the fluid, the pressure of a fluid inlet, the type and concentration or volume ratio of an inhibitor and the water content ratio.
A hydrate generation module: obtaining the total hydrate generation amount of the system by utilizing a first-order kinetic equation of hydrate generation based on the supercooling degree and the gas-water interface area of the submarine pipeline system; based on physical conditions, the generation amount of the hydrate cannot be a negative value, so that the condition that no hydrate is generated if the obtained supercooling degree in the supercooling degree module is a negative value or equal to 0 is limited, the condition that the phase change occurs in a pipeline if the supercooling degree is more than 0 is considered, and the heat transfer and the pressure distribution are violently changed due to the phase change.
A hydraulic diameter module: the hydrate can be settled and attached to the pipe wall due to gravity and flow factors, so that the flow diameter of the fluid is reduced, and the quantity describing the flow diameter is called hydraulic diameter; the hydraulic diameter is a limit to the flow rate of fluid in the system under the condition of certain flow of the submarine pipeline.
A heat transfer module: heat transfer includes the joule-thomson effect, the interaction of the environment, and the heat generated by phase changes. Joule-thomson effect refers to the temperature change of the fluid in the pipe flow due to a drastic change in pressure; the environment interaction means that the temperature of fluid transported by a submarine pipeline is usually higher than the environment temperature, so that the temperature of the fluid in the pipeline is continuously reduced to a hydrate stable region in the process of submarine long-distance transportation; the temperature change caused by phase change is easy to generate the hydrate under the conditions of high pressure and low temperature, and the environment of the submarine pipeline is just the hydrate generation interval, and the reaction is an exothermic reaction that gas molecules react with liquid water molecules to become solid.
A pressure module: in field measurement, due to the particularity of a submarine pipeline system, data capable of being directly detected is limited, most relevant values are obtained in an approximate range through monitoring pressure changes through an empirical formula, and therefore the pressure changes of a fluid inlet and a fluid outlet have great significance for evaluating the flow safety in the whole pipeline system. The pressure drop is increased due to hydrate generation, hydraulic diameter reduction and the like, the viscosity of the fluid is increased due to the hydrate generation, and the system needs larger energy to drive the fluid to advance; the hydraulic diameter of the pipeline is reduced due to adsorption and sedimentation of the hydrate, which has a great influence on pressure drop, and in addition, the pressure difference between an inlet and an outlet is increased due to the loss of gas and liquid caused by the generation of the hydrate.
The early warning module: when the system judges that the pressure drop before and after reaches a preset value, an early warning is provided for an operation platform, or related pipeline safety operation is carried out, and a pipeline is heated or cleaned.
Fig. 2 shows a flow chart of a subsea hydrocarbon pipeline transportation early warning method based on hydrate effect, the method comprising the following steps:
s1, collecting basic information of all pipelines in the area, wherein the basic information comprises the inner diameter of the pipeline, the outer diameter of the pipeline, the length of the pipeline, the material of the pipeline, the ambient temperature, the temperature of the fluid and the pressure of a fluid inlet; obtaining a hydrate equilibrium triple point through input parameters, fluid pressure and fluid temperature at an inlet of a seabed oil and gas pipeline;
ΔTsub＝teq-t
wherein, Delta TsubRepresented by the degree of supercooling, t, of the control systemeqRepresented as the equilibrium temperature of the control system and t as the temperature of the control system.
S2, calculating the hydrate generation amount through a first order kinetic formula of hydrate generation based on the supercooling degree of the pipeline system, and obtaining the variation trend of the hydraulic diameter along with the temperature and the pressure;
Figure BDA0002943227440000081
wherein the content of the first and second substances,
Figure BDA0002943227440000082
denotes the amount of hydrate formed per unit time, FkRepresenting the generation of hydratesCoefficient of formation, the value of which is related to the flow pattern of the fluid in the subsea pipeline, C1、C2Is a constant number, MgRepresents the average molar mass of the system fluid,
Figure BDA0002943227440000083
representing the average density of the system fluid, A representing the gas-water interface area in the control system;
A＝Adrop+Afilm
wherein A isdropRepresenting the gas-water interface area of the droplets dispersed in the gas phase in the system, AfilmRepresenting the gas-water interface area of a liquid film on the pipe wall of the submarine pipeline in the system;
s3, when the hydraulic diameter of the submarine pipeline is too small, the submarine pipeline is determined to be blocked, the state of the early warning system is judged, and early warning information is prompted to the platform equipment;
Figure BDA0002943227440000084
wherein the content of the first and second substances,
Figure BDA0002943227440000085
representing pressure changes per unit length in the pipe, f representing the coefficient of friction, pnsRepresenting the density of the fluid in the control system without sliding friction, DhRepresenting hydraulic diameter in a subsea pipeline, vmRepresenting the flow rate of the mixed fluid in the control system;
Figure BDA0002943227440000086
Figure BDA0002943227440000087
represents a temperature change per unit length, i.e., a temperature gradient; beta is aJTRepresents the char water coefficient, U represents the integrated heat transfer coefficient between the fluid and the environment in the control system, T represents the temperature of the fluid in the control system, and T represents the temperature of the fluid in the control systemextRepresents the ambient temperature, ΔH represents hydrate formation is exothermic, QmRepresenting the flow rate of fluid in the pipe per unit time, pmRepresenting the average density of the mixed fluid in the control system, CpmRepresenting the heat capacity of the mixed fluid in the control system;
Qm＝Qg+Ql
Qgrepresenting the flow rate of gas per unit time in the control system, QlRepresenting the flow rate of liquid per unit time in the control system.
The method is simulated by a backward iteration method, the pressure and temperature change in a control body and the hydraulic diameter change of a hydrate can be known through the formula, and the safety of the pipeline is comprehensively judged according to the parameters.
The gas-water interface area is introduced through the first-order hydrate generation formula, so that liquid drops dispersed in a gas phase and a liquid film on the pipe wall of the submarine pipeline can be considered at the same time, the generation amount of the hydrate in the pipeline can be predicted more accurately, and the blockage of the hydrate in the pipeline can be judged more accurately.
When the technical scheme is adopted for working: firstly, according to the collected pipeline related data of the ith section and the environment data, the equilibrium temperature of the pipeline of the ith section is calculated, then the supercooling degree of the pipeline system of the ith section is calculated, the generation amount of hydrate in the pipeline of the ith section is obtained, then the change value of the hydraulic diameter of the pipeline of the ith section along with time can be obtained, the change of the hydraulic diameter along with time influences the temperature and pressure initial state of the (i + 1) th section, and further iteration is carried out continuously, so that all values from a fluid inlet to a fluid outlet are obtained. The specific process is as follows:
(1) and setting initial conditions of the system according to the information collected by the collection module.
The collected data includes; the i-th section of the pipeline D has the environmental temperature t of 277KiInner diameter of 0.02m, i-th section of pipeline DoThe outer diameter is 0.025m, the pipeline length Deltax is 0.2m, the inlet pressure of the ith section is kept consistent with the outlet pressure of the ith-1 section, the inlet temperature of the ith section is kept consistent with the outlet temperature of the ith-1 section, and the gas flow Q of the ith section of pipelinegThe concentration of the water is 170L/min,the liquid flow of the i-th section of pipeline is 2.0L/min, and the supercooling degree of the i-th section of pipeline system is about 3.1 ℃ according to the collected data.
(2) And when the supercooling degree of the ith section is obtained, judging whether a hydrate is generated according to the supercooling degree, if the supercooling degree is a value smaller than 0, namely the temperature of the fluid in the pipeline is larger than the equilibrium temperature of the hydrate, determining that no hydrate is generated in the pipeline, and directly storing data such as temperature, pressure and the like to calculate the (i + 1) th section.
And (3) because the supercooling degree of the ith section is a value larger than 0, determining that the hydrate is generated in the ith section, calling a hydrate first-order kinetic generation formula, and calculating the generation amount of the hydrate in the ith section to be 0.4L/min according to a preset value in the simulation system, if the pressure difference in the simulation system reaches 1.4MPa, starting early warning. And obtaining the deposition thickness of the hydrate to be 0.003m, and calculating to obtain the hydraulic diameter of the ith section of pipeline to be 0.017 m. The pressure drop of the i-th section is calculated to be 6.5KPa through a pressure gradient and temperature gradient formula, the temperature gradient is 0.012 ℃, the data are stored and substituted into the initial condition of the i + 1-th section of the next iteration.
(3) When the flow safety condition of the pipeline at a certain time t is calculated, if the pressure difference obtained by subtracting the pressure at the pipeline inlet from the pressure at the pipeline outlet is greater than the preset value of the early warning system, if the pressure difference value of the pipeline per 100m monitored by the system is 1.2MPa by default, and if the pressure difference value calculated by the embodiment is 1.3MPa, the pipeline is determined to be blocked, and the early warning module is started.
The present invention is not limited to the particular embodiments described herein, but is capable of various obvious changes, rearrangements and substitutions as will now become apparent to those skilled in the art without departing from the scope of the invention. Therefore, although the present invention has been described in greater detail by the above embodiments, the present invention is not limited to the above embodiments, and may include other equivalent embodiments without departing from the spirit of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims (1)

1. An early warning method for simulating hydrate-plugged submarine gas pipeline transportation is characterized by comprising the following steps:
s1, collecting basic information of all pipelines in the area, wherein the basic information comprises the inner diameter of the pipeline, the outer diameter of the pipeline, the length of the pipeline, the material of the pipeline, the ambient temperature, the temperature of the fluid and the pressure of a fluid inlet;
s2, on the basis of physical conditions, the hydrate generation amount cannot be a negative value, so that if the supercooling degree obtained in the supercooling degree module is a negative value or equal to 0, no hydrate is generated; if the supercooling degree is more than 0, determining that phase change occurs in the pipeline and hydrate is generated;
ΔTsub＝teq-t
wherein, Delta TsubRepresented by the degree of supercooling, t, of the control systemeqRepresented as the equilibrium temperature of the control system, and t is represented as the temperature of the control system;
obtaining the total hydrate generation amount of the system based on the supercooling degree and the gas-water interface area of the submarine pipeline system;
Figure FDA0002943227430000011
wherein the content of the first and second substances,
Figure FDA0002943227430000012
denotes the amount of hydrate formed per unit time, FkRepresenting the formation coefficient of hydrates, whose value is related to the flow pattern of the fluid in the submarine pipeline, C1、C2Is a constant number, MgRepresents the average molar mass of the system fluid,
Figure FDA0002943227430000013
representing the average density of the system fluid, A representing the gas-water interface area in the control system;
A＝Adrop+Afilm
wherein A isdropRepresenting the gas-water cross-sectional area of the droplets dispersed in the gas phase in the system, AfilmRepresenting the gas-water interface area of the liquid film on the pipe wall of the submarine pipeline in the system；
Calculating the generation amount of the hydrate through a first-order kinetic formula of hydrate generation based on the supercooling degree of the pipeline system to obtain the variation trend of the hydraulic diameter along with the temperature and the pressure;
Figure FDA0002943227430000014
Figure FDA0002943227430000021
represents a temperature change per unit length, i.e., a temperature gradient; beta is aJTRepresents the char water coefficient, U represents the integrated heat transfer coefficient between the fluid and the environment in the control system, T represents the temperature of the fluid in the control system, and T represents the temperature of the fluid in the control systemextRepresenting ambient temperature,. DELTA.H representing hydrate formation being exothermic, QmRepresenting the flow rate of fluid in the pipe per unit time, pmRepresenting the average density of the mixed fluid in the control system, CpmRepresenting the heat capacity of the mixed fluid in the control system;
Qm＝Qg+Ql
Qgrepresenting the flow rate of gas per unit time in the control system, QlRepresenting the flow rate of liquid per unit time in the control system;
s3, evaluating the flow safety of the whole pipeline system by adopting the pressure difference between the fluid inlet and the fluid outlet; the pressure difference is increased when the hydrate is generated and the hydraulic diameter is reduced;
Figure FDA0002943227430000022
wherein the content of the first and second substances,
Figure FDA0002943227430000023
representing pressure changes per unit length in the pipe, f representing the coefficient of friction, pnsRepresenting the density of the fluid in the control system without sliding friction, DhRepresenting the sea bottomHydraulic diameter in pipe, vmRepresenting the flow rate of the mixed fluid in the control system;
simulating by a backward iteration method, controlling the pressure and temperature change in the body and the hydraulic diameter change caused by hydrate to cause the inlet and outlet pressure difference change of the submarine pipeline, and comprehensively judging the safety of the pipeline by the pressure difference change; when the hydraulic diameter of the submarine pipeline is too small, and the system judges that the pressure difference between the inlet and the outlet of the pipeline reaches a preset value, the submarine pipeline is determined to be blocked, and early warning information is prompted to the platform equipment.
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Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102022619A (en) * 2009-09-16 2011-04-20 中国石油大学(北京) Functional compound inhibitor and method of inhibiting hydrate accumulation and paraffin deposition
KR20130127760A (en) * 2012-05-15 2013-11-25 삼성중공업 주식회사 Pipe preventing hydrate forming
CN103675213A (en) * 2013-12-20 2014-03-26 华南理工大学 Simulating device for fluid flow safety evaluation of oil-gas pipelines
CN104390902A (en) * 2014-11-20 2015-03-04 大连理工大学 Method for analyzing pore distribution of sediment by virtue of saturation change of gas hydrate
CN106194165A (en) * 2016-08-26 2016-12-07 中国石油大学(华东) Gas hydrates blocking monitoring device and method in the test of deep water gas well
CN106322121A (en) * 2016-08-26 2017-01-11 中国石油大学(华东) Early monitoring device and method for hydrate blockage of deep water gas well production pipeline
CN110674572A (en) * 2019-09-18 2020-01-10 西南石油大学 Method for predicting natural gas hydrate generation area in seabed gas transmission pipeline

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102022619A (en) * 2009-09-16 2011-04-20 中国石油大学(北京) Functional compound inhibitor and method of inhibiting hydrate accumulation and paraffin deposition
KR20130127760A (en) * 2012-05-15 2013-11-25 삼성중공업 주식회사 Pipe preventing hydrate forming
CN103675213A (en) * 2013-12-20 2014-03-26 华南理工大学 Simulating device for fluid flow safety evaluation of oil-gas pipelines
CN104390902A (en) * 2014-11-20 2015-03-04 大连理工大学 Method for analyzing pore distribution of sediment by virtue of saturation change of gas hydrate
CN106194165A (en) * 2016-08-26 2016-12-07 中国石油大学(华东) Gas hydrates blocking monitoring device and method in the test of deep water gas well
CN106322121A (en) * 2016-08-26 2017-01-11 中国石油大学(华东) Early monitoring device and method for hydrate blockage of deep water gas well production pipeline
CN110674572A (en) * 2019-09-18 2020-01-10 西南石油大学 Method for predicting natural gas hydrate generation area in seabed gas transmission pipeline

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