CN114112695A - Pipeline life prediction method and pipeline life prediction device - Google Patents
Pipeline life prediction method and pipeline life prediction device Download PDFInfo
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- G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N3/08—Investigating strength properties of solid materials by application of mechanical stress by applying steady tensile or compressive forces
- G01N3/10—Investigating strength properties of solid materials by application of mechanical stress by applying steady tensile or compressive forces generated by pneumatic or hydraulic pressure
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- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N3/08—Investigating strength properties of solid materials by application of mechanical stress by applying steady tensile or compressive forces
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- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N3/08—Investigating strength properties of solid materials by application of mechanical stress by applying steady tensile or compressive forces
- G01N3/18—Performing tests at high or low temperatures
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- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/0014—Type of force applied
- G01N2203/0016—Tensile or compressive
- G01N2203/0017—Tensile
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- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/0014—Type of force applied
- G01N2203/0016—Tensile or compressive
- G01N2203/0019—Compressive
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/003—Generation of the force
- G01N2203/0042—Pneumatic or hydraulic means
- G01N2203/0048—Hydraulic means
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- G—PHYSICS
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- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
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- G01N2203/0067—Fracture or rupture
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- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/02—Details not specific for a particular testing method
- G01N2203/022—Environment of the test
- G01N2203/0222—Temperature
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/02—Details not specific for a particular testing method
- G01N2203/022—Environment of the test
- G01N2203/0222—Temperature
- G01N2203/0226—High temperature; Heating means
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/02—Details not specific for a particular testing method
- G01N2203/022—Environment of the test
- G01N2203/0236—Other environments
- G01N2203/024—Corrosive
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/02—Details not specific for a particular testing method
- G01N2203/026—Specifications of the specimen
- G01N2203/0262—Shape of the specimen
- G01N2203/0274—Tubular or ring-shaped specimens
Abstract
The invention provides a pipeline service life prediction method and a pipeline service life prediction device, wherein the pipeline service life prediction method comprises the steps of carrying out first detection operation on each group of test pipelines in a plurality of groups of test pipelines so as to obtain the hydrostatic pressure time and the bursting strength value of each group of test pipelines, and determining a first fitting equation between the hydrostatic pressure time and the bursting strength value; performing second detection operation on each group of test pipelines in the plurality of groups of test pipelines to obtain the soaking time and the failure strength value of the inner liner test sample corresponding to each group of test pipelines, and determining a second fitting equation between the soaking time and the failure strength value; obtaining an intensity and time equation of the test pipeline under the combined action of hydrostatic pressure and a corrosive medium according to the first fitting equation and the second fitting equation; and outputting the expected life of the target pipeline according to the safety critical pressure and the strength of the target pipeline and a time equation. The method is used for predicting the service life of the pipeline and avoiding safety accidents such as pipeline leakage or burst.
Description
Technical Field
The invention relates to the technical field of service life prediction, in particular to a pipeline service life prediction method and a pipeline service life prediction device.
Background
The pipeline is a common component for transporting fluid, such as oil, natural gas, water, etc., and the material of the pipeline can be metal or nonmetal.
The flexible composite pipe for conveying the petroleum and natural gas is taken as an example and comprises an inner liner, a fiber layer and a protective layer, wherein the inner liner, the fiber layer and the protective layer are sequentially attached from inside to outside, the petroleum and natural gas flows in the flexible composite pipe under set pressure and temperature, and the inner liner is directly contacted with the petroleum and natural gas.
The petroleum and natural gas are corrosive, under the combined action of temperature and pressure, the conditions of ageing degradation of the inner liner, fiber layer fracture and the like can occur, the strength of the flexible composite pipe is low, and if the conditions cannot be found, safety accidents such as leakage or burst of the flexible composite pipe easily occur.
Disclosure of Invention
In view of the foregoing problems, embodiments of the present invention provide a method and a device for predicting a service life of a pipeline, which are used to predict a service life of the pipeline and avoid safety accidents such as pipeline leakage or burst.
In order to achieve the above object, the embodiments of the present invention provide the following technical solutions:
a first aspect of an embodiment of the present invention provides a method for predicting a life of a pipeline, including: performing a first detection operation on each group of test pipelines in the plurality of groups of test pipelines to obtain hydrostatic pressure time and a bursting strength value of each group of test pipelines, and determining a first fitting equation between the hydrostatic pressure time and the bursting strength value; performing second detection operation on each group of test pipelines in the plurality of groups of test pipelines to obtain the soaking time and the failure strength value of the inner liner test sample corresponding to each group of test pipelines, and determining a second fitting equation between the soaking time and the failure strength value; obtaining an intensity and time equation of the test pipeline under the combined action of hydrostatic pressure and a corrosive medium according to the first fitting equation and the second fitting equation; and outputting the expected life of the target pipeline according to the safety critical pressure of the target pipeline and the strength and time equation.
The method for predicting the service life of the pipeline, wherein the performing a first detection operation on each group of test pipelines in the multiple groups of test pipelines to obtain the hydrostatic time and the burst strength value of each group of test pipelines specifically includes: performing hydrostatic pressure test on each group of test pipelines in the plurality of groups of test pipelines, and detecting the hydrostatic pressure time of each group of test pipelines; and carrying out a blasting test on the test pipelines after the hydrostatic test, and detecting the blasting strength value of each group of test pipelines.
The method for predicting the service life of the pipeline, wherein the determining a first fitted equation between the hydrostatic time and the burst strength value specifically includes: determining the first fitted equation according to the formula Ph ═ a × ln (t) + b, wherein Ph is the burst strength value, t is the hydrostatic time, and a and b are constants.
The method for predicting the service life of the pipeline, wherein the second detection operation is performed on each group of test pipelines in the plurality of groups of test pipelines to obtain the soaking time and the failure strength value of the inner liner test sample corresponding to each group of test pipelines, specifically includes: soaking the inner liner samples corresponding to each group of test pipelines in a corrosive medium, and detecting the soaking time of each group of inner liner samples; stretching the soaked lining layer samples, and detecting the yield strength value of each group of lining layer samples; and obtaining the failure strength value of each group of the inner liner samples according to the yield strength value.
The method for predicting the service life of the pipeline, wherein the step of soaking the inside liner samples corresponding to each group of the test pipelines in a corrosive medium and detecting the soaking time of each group of the inside liner samples, specifically comprises the steps of: pouring the corrosive medium into the soaking container; soaking the lining layer sample in the corrosive medium and stirring the corrosive medium; and after the inner liner sample reaches the corresponding soaking time, taking out the inner liner sample from the corrosive medium, and detecting the soaking time of the inner liner sample.
The method for predicting the service life of the pipeline, wherein the obtaining of the failure strength value of each group of the lining layer test samples according to the yield strength value specifically comprises the following steps: determining the failure strength value of the inner liner sample according to a formula Pc-2 h Sigma/(D-h); the inner liner comprises a sample, a sample layer and a sample layer, wherein Pc is the failure strength value, sigma is the yield strength value of the sample layer, D is the outer diameter of the inner liner layer, and h is the thickness of the inner liner layer.
The method for predicting the service life of the pipeline, wherein the determining of the second fitted equation between the soaking time and the failure strength value specifically includes: determining the second fitting equation according to a formula Pc ═ c × ln (t) + d, where Pc is the failure intensity value, t is the soaking time, and c and d are constants.
The method for predicting the service life of the pipeline, wherein the equation of the soaking time and the intensity attenuation value is obtained according to a second fitting equation between the soaking time and the failure intensity value, and specifically comprises the following steps: determining the soaking time and intensity attenuation value equation according to a formula Δ Pc ═ e × (n) (t), wherein Δ Pc is the intensity attenuation value, t is the soaking time, and e is a constant.
The method for predicting the service life of the pipeline, wherein the obtaining of the equation of the strength and the time of the test pipeline under the joint action of the hydrostatic pressure and the corrosive medium according to the first fitted equation and the second fitted equation specifically includes: obtaining an equation of the strength and the time of the test pipeline under the combined action of hydrostatic pressure and a corrosive medium according to the first fitting equation and the equation of the soaking time and the strength attenuation value: pt + α Δ Pc ═ (a + α × e) × (n) (t) + a × b, where Pt is the strength under the combined action of the hydrostatic pressure and the corrosive medium, Ph is the burst strength value, Δ Pc is the strength decay value, t is the time under the combined action of the hydrostatic pressure and the corrosive medium, α is the medium correlation coefficient, and a, b, and e are constants.
Compared with the prior art, the pipeline service life prediction method provided by the embodiment of the invention has the following advantages: the method comprises the following tests, wherein the pressure applied to a pipeline when petroleum and natural gas flow through the pipeline is simulated by carrying out first detection operation on a plurality of groups of test pipelines, and each group of test pipelines can carry out hydrostatic pressure tests in different set time; carrying out a blasting test on a plurality of groups of test pipelines subjected to the hydrostatic test to obtain a first fitting equation of different hydrostatic times and different blasting strength values; in addition, a plurality of groups of test pipelines are selected, the lining layer samples of each group of test pipelines are obtained, a soaking test of corrosive media is carried out, the working state that the lining layer is in direct contact with petroleum and natural gas is simulated, and the soaking test of each group of lining layer samples can be carried out at different set time; performing a tensile strength test on the inner liner samples subjected to the soaking test to obtain a yield strength value of each group of inner liner samples, and correspondingly obtaining a failure strength value of each group of inner liner samples, so that a second fitting equation of the soaking time and the failure strength value of each group of inner liner samples can be obtained through fitting; through the first fitting equation and the second fitting equation, an intensity and time equation under the combined action of hydrostatic pressure and a corrosion medium can be obtained; the safety critical pressure of the pipeline is substituted into the strength and time equation, and the expected service life of the target pipeline can be output. The embodiment of the invention simulates the working conditions of the pipeline in the actual process of conveying the petroleum and the natural gas, has high prediction reliability and avoids the safety accidents of leakage or burst and the like of the pipeline.
A second aspect of an embodiment of the present invention provides a pipe life prediction apparatus, which includes a processor and a memory, where the memory stores a computer program, and the processor executes the computer program stored in the memory to make the apparatus execute the method according to the first aspect.
In addition to the technical problems solved by the embodiments of the present invention, the technical features constituting the technical solutions, and the advantages brought by the technical features of the technical solutions, other technical problems that can be solved by the method and the apparatus for predicting a lifetime of a pipeline according to the embodiments of the present invention, other technical features included in the technical solutions, and advantages brought by the technical features will be further described in detail in the detailed description.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and those skilled in the art can also obtain other drawings according to the drawings without creative efforts.
FIG. 1 is a flow chart of a method for predicting the service life of a pipeline according to an embodiment of the present invention;
FIG. 2 is a flow chart of a first test operation performed on the test line of FIG. 1;
FIG. 3 is a flow chart of a second test operation performed on the test line of FIG. 1;
FIG. 4 is a flow chart of a corrosive media immersion test performed on the lining layer sample of FIG. 3;
FIG. 5 is a schematic structural diagram of a device for predicting the life of a pipeline according to an embodiment of the present invention;
FIG. 6 is a graph of a hydrostatic time versus burst strength value fit provided by an embodiment of the present invention;
FIG. 7 is a graph of a fitted immersion time versus failure strength value graph according to an embodiment of the present invention;
FIG. 8 is a graph of strength versus time under the combined action of hydrostatic pressure and corrosive media provided in accordance with an embodiment of the present invention.
Detailed Description
In order to make the aforementioned objects, features and advantages of the embodiments of the present invention more comprehensible, embodiments of the present invention are described in detail below with reference to the accompanying drawings. It is to be understood that the described embodiments are merely a few embodiments of the invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Considering that petroleum and natural gas have certain corrosivity, and metal pipelines such as carbon steel and the like are easy to corrode, so that the strength of the metal pipelines is reduced and even broken, and the petroleum and natural gas cannot be safely and effectively conveyed, the non-metal pipelines with strong corrosion resistance such as flexible composite pipes and the like are widely applied to the field of petroleum and natural gas conveying.
However, in the process of conveying the petroleum and natural gas, the flexible composite pipe still can be corroded by the petroleum and natural gas, and under the combined action of the temperature and the pressure of the petroleum and natural gas, the conditions of ageing and degradation of the inner liner, fiber layer fracture and the like can occur, the strength of the flexible composite pipe becomes low, and if the conditions cannot be found in time, safety accidents such as leakage or burst of the flexible composite pipe easily occur. In view of this, the service life of the flexible composite pipe can be predicted by simulating the actual working condition of the flexible composite pipe, and the flexible composite pipe is replaced or maintained in time before the service life of the flexible composite pipe is reached, so that safety accidents such as leakage or burst of the flexible composite pipe are avoided.
Fig. 1 is a flowchart of a method for predicting a life of a pipeline according to an embodiment of the present invention. Fig. 2 is a flowchart of a first inspection operation performed on the test line of fig. 1. Fig. 3 is a flowchart of a second inspection operation performed on the test line of fig. 1. FIG. 4 is a flow chart of the erosion media immersion test performed on the lining layer sample of FIG. 3. Referring to fig. 1 to 4, the present embodiment provides a method for predicting a service life of a flexible composite pipe, including:
s101, carrying out first detection operation on each group of test pipelines in the multiple groups of test pipelines to obtain the hydrostatic time and the bursting strength value of each group of test pipelines and determine a first fitting equation between the hydrostatic time and the bursting strength value.
To reduce testing errors, multiple sets of test tubes may be of the same batch, such that each test tube may be made from the same manufacturing process and the same raw materials, and each test tube has the same nominal pressure, the same nominal diameter, and the same wall thickness.
The length of the test pipe may be at least 5 times the nominal diameter, and for example, when the nominal diameter of the test pipe is less than or equal to 150mm, the length of the test pipe may be at least 900 mm. When the nominal diameter of the test tube is greater than 150mm, the length of the test tube may be greater than or equal to 1200 mm. The number of groups of test pipelines can be at least 6, and each group of test pipelines at least comprises 2 test pipelines.
Wherein, first detection operation includes that each group's test pipeline in the multiunit test pipeline carries out hydrostatic test to detect the hydrostatic time of each group's test pipeline.
The test fluid for hydrostatic pressure test can be water, or a simulated fluid of petroleum and natural gas, etc. Taking water as an example, the temperature of the water can be the conveying temperature of the petroleum and natural gas, the pressure of the water can be 1.5 times of the nominal pressure of the test pipeline, and the water flows into the test pipeline from one end of the test pipeline and flows out from the other end of the test pipeline so as to simulate the conveying process of the petroleum and natural gas.
Each group of test pipelines corresponds to different hydrostatic pressure time, and the hydrostatic pressure time can be randomly selected from 1 hour to 2000 hours. Wherein, at least 1 time point is selected within 100 hours, at least 3 time points are selected between 100 hours and 1000 hours, and at least 2 time points are selected between 1500 hours and 2000 hours, so as to reduce the test error. Taking 8 sets of test tubes as an example, the 8 sets of test tubes can be subjected to hydrostatic pressures for 50 hours, 100 hours, 250 hours, 550 hours, 900 hours, 1350 hours, 1900 hours, 2000 hours, respectively.
The first detection operation further comprises carrying out a blasting test on the test pipelines after the hydrostatic test, and detecting the blasting strength value of each group of test pipelines.
After the hydrostatic test is completed, according to the standard GB5351 'short-time hydraulic failure pressure test method for fiber reinforced thermosetting plastic pipes', the test pipelines after the hydrostatic test are respectively subjected to a bursting test, the bursting strength value of each test pipeline is recorded, and the average bursting strength value of each group of test pipelines is calculated and recorded.
And carrying out numerical value fitting on the hydrostatic time and the bursting strength value of each group of test pipelines to obtain a first fitting equation of the hydrostatic time and the bursting strength value. Specifically, the logarithm of the hydrostatic time is used as a horizontal coordinate, the blasting strength value is used as a vertical coordinate, data fitting is carried out by using a logarithmic regression method, and a first fitting equation of the hydrostatic time and the blasting strength value is obtained.
The first fitting equation can be determined from Ph ═ a × ln (t) + b, (1)
Wherein Ph is a bursting strength value and the unit is megapascal and MPa; t is hydrostatic pressure time, and the unit is hour and h; a is a constant; b is a constant.
S102, carrying out second detection operation on each group of test pipelines in the plurality of groups of test pipelines to obtain the soaking time and the failure strength value of the inner liner test sample corresponding to each group of test pipelines, and determining a second fitting equation between the soaking time and the failure strength value.
And reselecting a plurality of groups of test pipelines in the test pipelines of the same batch for the blasting test, stripping the inner liners of the test pipelines, and cutting a plurality of groups of inner liner samples. The number of sets of lining samples may be at least 5, each set of lining samples comprising at least 5 sheets of lining samples. The shape of the lining layer sample can be dumbbell-shaped or other shapes which are convenient to clamp.
Considering that the petroleum and natural gas are corrosive, the second detection operation may include immersing the lining layer samples corresponding to each group of test pipelines in a corrosive medium, and detecting the immersion time of each group of lining layer samples. Specifically, a corrosive medium can be poured into the soaking container; soaking the lining layer sample in a corrosive medium and stirring the corrosive medium; and after the lining layer sample reaches the corresponding soaking time, taking out the lining layer sample from the corrosive medium, and detecting the soaking time of the lining layer sample.
Since the petroleum and natural gas has flowing pressure in the flexible composite pipe, the soaking container may be a pressure container capable of withstanding pressure so as to adjust the pressure in the soaking container to the delivery pressure of the petroleum and natural gas. In order to accurately predict the service life of the flexible composite pipe, the soaking medium in the soaking container can be a simulation medium of petroleum and/or natural gas, when a corrosion medium soaking test is carried out, the lining layer sample is soaked in the simulation medium of the petroleum and/or natural gas, the working condition that the lining layer is directly contacted with the petroleum or natural gas when the flexible composite pipe conveys the petroleum and natural gas is simulated, and the service life prediction accuracy is improved.
When a corrosion medium immersion test is carried out, a corrosion medium is poured into the immersion container, wherein the corrosion medium can be corrosive liquid to simulate petroleum and formation water, can also be corrosive gas to simulate natural gas, and can also simultaneously comprise the corrosive liquid and the corrosive gas to simulate the hydrogen sulfide H mixed in the petroleum2S, carbon dioxide CO2Or methane CH4And the like under the working conditions of harmful gases. Alternatively, the corrosive liquid may be a mixture of crude oil and the formation water simulation medium, the mixture ratio of the crude oil to the formation water simulation medium may be 2:8 or 3:7, and the like, and the present embodiment is not limited, and the ion concentration of the formation water simulation medium may be consistent with the formation water at the position of the oil and gas transmission pipeline.
And the pressure of the corrosion medium immersion test can be adjusted to be the conveying pressure of the petroleum and natural gas, and the temperature of the corrosion medium can be the conveying temperature of the petroleum and natural gas, namely the test temperature of the hydrostatic test is the same as the test temperature of the immersion test, and is 15 ℃ lower than the Vicat softening temperature of the inner liner.
Simultaneously, for simulating the flowing condition of petroleum and natural gas, after each group of lining layer samples are soaked in the corrosive medium, the corrosive medium is stirred, so that the corrosive medium can flow relative to the lining layer samples. The stirring speed may be 60 rpm to 120 rpm.
Accordingly. Each group of inner liner samples correspond to different soaking times, and after each group of inner liner samples reach the corresponding soaking time, the inner liner samples are taken, and the soaking time of each group of inner liner samples is recorded.
The soaking time can be randomly selected from 10 hours to 800 hours, wherein at least 1 time point is selected within 100 hours, at least 3 time points are selected between 100 hours and 500 hours, and at least 1 time point is selected between 500 hours and 800 hours, so that the test error is reduced. Taking the sample with 6 sets of liners as an example, the soaking time for the 6 sets of liner samples can be 60 hours, 160 hours, 300 hours, 450 hours, 600 hours, 780 hours.
The second detection operation can also comprise the steps of stretching the soaked inner liner samples, detecting the yield strength value of each group of inner liner samples, and obtaining the failure strength value of each group of inner liner samples according to the yield strength value.
And after the corrosion medium soaking test is finished, performing a tensile strength test on each in-chip lining sample on a material testing machine to obtain the yield strength value of each in-chip lining sample. And simultaneously, carrying out a tensile strength test on a group of lining layer samples which are not subjected to the corrosion medium immersion test to obtain the initial yield strength value of the lining layer samples which are not subjected to the corrosion medium immersion test.
Obtaining a conversion equation of the failure strength value of each group of the lining layer samples according to the yield strength value of each group of the lining layer samples, wherein the conversion equation is as follows:
and determining the failure strength value of the inner liner sample according to the formula Pc-2 h Sigma/(D-h). (2)
Wherein Pc is the failure strength value and has the unit of megapascal and MPa; the Be is the yield strength value of the inner liner sample, and the unit is megapascal and MPa; d is the outer diameter of the lining layer, and the unit is millimeter and mm; and h is the thickness of the inner liner layer, and the unit is millimeter and mm.
And performing numerical fitting according to the soaking time and the failure strength value of each group of the inner liner samples to obtain a second fitting equation of the soaking time and the failure strength value. Specifically, the logarithm of the soaking time is used as a horizontal coordinate, the failure strength value is used as a vertical coordinate, and a logarithmic regression method is used for data fitting to obtain a second fitting equation of the soaking time and the failure strength value.
The second fitting equation may be determined from Pc ═ c × ln (t) + d.
Wherein Pc is a failure strength value and has the unit of megapascal and MPa; t is the soaking time, the unit is hour, h; c is a constant; d is a constant.
According to the second fitting equation, an equation of the soaking time and the intensity attenuation value can be obtained:
ΔPc＝e*ln(t)。 (3)
wherein, the DeltaPc is the intensity attenuation value with the unit of megapascal and MPa; t is the soaking time, the unit is hour, h; e is a constant.
S103, introducing a medium correlation coefficient alpha, and obtaining an intensity and time equation under the combined action of hydrostatic pressure and a corrosion medium according to equation (1) and equation (3). The equation can be based on
Pt + α Δ Pc ═ (a + α · e) × ln (t) + a · b. (4)
In the formula, Pt is the strength under the combined action of hydrostatic pressure and a corrosion medium, and the unit is megapascal and MPa; ph is a bursting strength value and has the unit of megapascal and MPa; Δ Pc is the intensity attenuation in MPa; t is the time under the combined action of hydrostatic pressure and a corrosive medium, and the unit is hour and h; alpha is a dielectric correlation coefficient, and is 3.0 ≦ alpha ≦ 5.0; a is a constant; b is a constant; e is a constant.
S104, the expected life of the flexible composite pipe can be defined as the time length of the flexible composite pipe working under the safety critical pressure, and the expected life of the flexible composite pipe can be obtained through inputting the safety critical pressure of the flexible composite pipe into the equation (4) and outputting.
Wherein the safe critical pressure is: ps ═ f × Pn, (5)
Wherein, Ps is the safe critical pressure, and the unit is megapascal and MPa; pn is the nominal pressure of the target pipeline, and the unit is megapascal and MPa; f is a safety factor, and f is less than or equal to 1.0 and less than or equal to 2.0.
The method for predicting the service life of the pipeline provided by the embodiment considers the influence of the long-term bearing of the pressure of the petroleum and natural gas on the burst strength of the pipeline, and establishes a fitting equation of hydrostatic pressure time and the burst strength; considering the influence of the corrosivity of petroleum and natural gas on the service life of the pipeline, a fitting equation of the soaking time and the intensity attenuation value of the lining layer sample is established, and the expected service life of the pipeline can be obtained by setting different safety critical pressures. The pipeline service life prediction method provided by the embodiment simulates the working condition of the pipeline in the process of conveying petroleum and natural gas, and is high in prediction reliability, short in test period and convenient to implement.
Fig. 5 is a schematic structural diagram of a device for predicting the life of a pipeline according to an embodiment of the present invention. Referring to fig. 5, the present embodiment further provides a pipe life prediction apparatus 10 for executing the method, where the pipe life prediction apparatus 10 includes a processor 11 and a memory 12, a computer program is stored in the memory 12, and the processor 11 executes the computer program stored in the memory, so that the pipe life prediction apparatus 10 executes the method for predicting the pipe life. The specific operation steps of the pipeline life prediction method have been described in the above embodiments, and are not described herein again.
Alternatively, the memory 12 may be separate or integrated with the processor 11.
When the memory 12 is provided separately, the pipe life prediction apparatus further includes a bus 13 for connecting the memory 12 and the processor 11.
An embodiment of the present invention further provides a computer-readable storage medium, where a computer executing instruction is stored in the computer-readable storage medium, and when a processor executes the computer executing instruction, the method for predicting a life of a pipeline as described above is implemented.
In the embodiments provided in the present invention, it should be understood that the disclosed apparatus and method may be implemented in other ways. For example, the above-described apparatus embodiments are merely illustrative, and for example, the division of the modules is only one logical division, and other divisions may be realized in practice, for example, a plurality of modules may be combined or integrated into another system, or some features may be omitted, or not executed. In addition, the shown or discussed mutual coupling or direct coupling or communication connection may be an indirect coupling or communication connection through some interfaces, devices or modules, and may be in an electrical, mechanical or other form.
The modules described as separate parts may or may not be physically separate, and parts displayed as modules may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the modules may be selected according to actual needs to implement the solution of the present embodiment.
In addition, functional modules in the embodiments of the present invention may be integrated into one processing unit, or each module may exist alone physically, or two or more modules are integrated into one unit. The unit formed by the modules can be realized in a hardware form, and can also be realized in a form of hardware and a software functional unit.
The integrated module implemented in the form of a software functional module may be stored in a computer-readable storage medium. The software functional module is stored in a storage medium and includes several instructions for causing a computer device (which may be a personal computer, a server, or a network device) or a processor to execute some steps of the methods described in the embodiments of the present application.
It should be understood that the Processor may be a Central Processing Unit (CPU), other general purpose Processor, a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), etc. A general purpose processor may be a microprocessor or the processor may be any conventional processor or the like. The steps of a method disclosed in connection with the present invention may be embodied directly in a hardware processor, or in a combination of the hardware and software modules within the processor.
The memory may comprise a high-speed RAM memory, and may further comprise a non-volatile storage NVM, such as at least one disk memory, and may also be a usb disk, a removable hard disk, a read-only memory, a magnetic or optical disk, etc.
The bus may be an Industry Standard Architecture (ISA) bus, a Peripheral Component Interconnect (PCI) bus, an Extended ISA (Extended Industry Standard Architecture) bus, or the like. The bus may be divided into an address bus, a data bus, a control bus, etc. For ease of illustration, the buses in the figures of the present application are not limited to only one bus or one type of bus.
The storage medium may be implemented by any type or combination of volatile or non-volatile memory devices, such as Static Random Access Memory (SRAM), electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EPROM), programmable read-only memory (PROM), read-only memory (ROM), magnetic memory, flash memory, magnetic or optical disks. A storage media may be any available media that can be accessed by a general purpose or special purpose computer.
An exemplary storage medium is coupled to the processor such the processor can read information from, and write information to, the storage medium. Of course, the storage medium may also be integral to the processor. The processor and the storage medium may reside in an Application Specific Integrated Circuits (ASIC). Of course, the processor and the storage medium may reside as discrete components in an electronic device or host device.
Those of ordinary skill in the art will understand that: all or a portion of the steps of implementing the above-described method embodiments may be performed by hardware associated with program instructions. The program may be stored in a computer-readable storage medium. When executed, the program performs steps comprising the method embodiments described above; and the aforementioned storage medium includes: various media capable of storing program codes, such as ROM, RAM, magnetic disk or optical disk
Fig. 6 is a graph of a hydrostatic time and a burst strength value according to an embodiment of the present invention. FIG. 7 is a graph of a fitted soaking time and failure strength value provided by an embodiment of the present invention. FIG. 8 is a graph of strength versus time under the combined action of hydrostatic pressure and corrosive media provided in accordance with an embodiment of the present invention. Referring to fig. 6 to 8, the method for predicting the life of the pipeline will be described in detail by way of specific examples.
The service life of the polyester fiber reinforced flexible composite pipe with the inner lining layer of 85.3mm in outer diameter, the wall thickness of 3.1mm and the nominal pressure of 4MPa is predicted.
The method comprises the steps of randomly selecting 18 flexible composite pipes in the same batch, cutting the lengths of the 18 flexible composite pipes into 1500mm, and installing plugging joints at two ends of each flexible composite pipe so as to conveniently introduce hydrostatic pressure media into the flexible composite pipes, wherein the hydrostatic pressure media can be tap water.
Taking 3 flexible composite pipes as a group, dividing 18 flexible composite pipes into 6 groups and respectively labeling, performing hydrostatic pressure experiments according to the pressure and temperature conditions shown in table 1, and respectively recording the hydrostatic pressure time of each group of flexible composite pipes, wherein the hydrostatic pressure time of each group of flexible composite pipes refers to table 1.
After the hydrostatic test is completed, according to the standard GB5351 "short time hydrostatic failure pressure test method for fiber reinforced thermosetting plastic pipes", the test pipes after the hydrostatic test are subjected to a burst test, the burst strength value of each flexible composite pipe is recorded, the average burst strength value of each group of flexible composite pipes is calculated and recorded, and the burst strength value of each flexible composite pipe and the average burst strength value of each group of flexible composite pipes refer to table 1.
TABLE 1 hydrostatic pressure test and burst Strength test
And taking the logarithm of the hydrostatic time as a horizontal coordinate and the burst strength value as a vertical coordinate, and performing data fitting by using a logarithmic regression method to obtain a first fitting equation of the hydrostatic time and the burst strength value.
I.e., Ph 19.32-1.062ln (t). (6)
Meanwhile, selecting the flexible composite pipes in the same batch as the 18 flexible composite pipes, peeling off the lining layer, manufacturing 30 dumbbell-shaped lining layer samples, taking 5 pieces of lining layer samples as a group, and dividing 30 pieces of lining layer samples into 6 groups and respectively marking. The soaking container can be an autoclave, 4L of liquid phase simulated corrosion medium shown in table 2 is injected into the autoclave, any 5 groups of inner liner samples of the clamping piece are soaked in the liquid phase simulated corrosion medium, and CO with the medium content in the process of injecting petroleum and natural gas into the autoclave2Then injecting nitrogen N into the autoclave2The pressure in the autoclave was adjusted to 3.5MPa to be equal to the transport pressure of petroleum and natural gas. Adjusting the temperature in the autoclave to 70 ℃, starting a stirring device of the autoclave, stirring the liquid phase simulated corrosion medium at a stirring speed of 60 revolutions per minute, and stirring CO in the process2Can be mixed with a liquid phase simulated corrosion medium to simulate the transportation process of petroleum and natural gas.
The soaking time of the 5 groups of the samples of the inner liner can be 30 hours, 120 hours, 240 hours, 360 hours and 720 hours respectively, and the samples of the inner liner of any one of the progenitor groups are taken out from the autoclave after the soaking time is finished.
TABLE 2 corrosive media immersion test
And (3) performing a tensile strength test on each sheet of inner liner sample, recording the yield strength value of each sheet of inner liner sample, calculating to obtain the average yield strength value of each group of inner liner samples, and calculating to obtain the failure strength value of each group of inner liner samples according to an equation (2), wherein the values are shown in a table 3.
And (3) performing a tensile strength test on another group of lining layer samples which are not subjected to the corrosion soaking test, recording the initial yield strength value of each group of lining layer samples, calculating the average yield strength value of the group of lining layer samples, and calculating the failure strength value of the group of lining layer samples according to equation (2), wherein the failure strength value is shown as 0# in table 3.
TABLE 3 soak time and Strength to failure values for the innerliner samples
And taking the logarithm of the soaking time as an abscissa and the failure strength value as an ordinate, and performing data fitting on the 6 groups of data in the table 3 by using a logarithmic regression method to obtain a second fitting equation of the soaking time and the failure strength value.
Namely Pc-1.4705-0.027 ln (t).
And obtaining an equation of the soaking time and the intensity attenuation value, namely that the delta Pc is-0.027 ln (t). (7)
And (3) taking the medium correlation coefficient alpha as 3.5, and substituting equation (6) and equation (7) into equation (4) to obtain an equation of strength and time under the combined action of hydrostatic pressure and corrosive medium.
Namely Pt + Ph + α Δ Pc 19.32 to 1.156ln (t). (8)
When the nominal pressure of the flexible composite pipe is 4MPa and the safety coefficient f is 1.5, the safety critical pressure Ps of the flexible composite pipe is 6MPa through calculation of equation (5), Pt is taken as Ps, and the expected life of the flexible composite pipe is calculated as t, which is 11 years through calculation of equation (8).
It can be understood that when the nominal pressure of the flexible composite pipe is 4MPa, and the safety factor f is 1.2, the safety critical pressure Ps of the flexible composite pipe is 4.8MPa, Pt is Ps, and the expected life of the flexible composite pipe is t 30 years, which is calculated by equation (8), according to equation (5).
The embodiments or implementation modes in the present specification are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments may be referred to each other.
In the description of the present specification, reference to the description of the terms "one embodiment", "some embodiments", "an illustrative embodiment", "an example", "a specific example", or "some examples", etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.
Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.
Claims (10)
1. A method of predicting a life of a pipeline, comprising:
performing a first detection operation on each group of test pipelines in the plurality of groups of test pipelines to obtain hydrostatic pressure time and a bursting strength value of each group of test pipelines, and determining a first fitting equation between the hydrostatic pressure time and the bursting strength value;
performing second detection operation on each group of test pipelines in the plurality of groups of test pipelines to obtain the soaking time and the failure strength value of the inner liner test sample corresponding to each group of test pipelines, and determining a second fitting equation between the soaking time and the failure strength value;
obtaining an intensity and time equation of the test pipeline under the combined action of hydrostatic pressure and a corrosive medium according to the first fitting equation and the second fitting equation;
and outputting the expected life of the target pipeline according to the safety critical pressure of the target pipeline and the strength and time equation.
2. The method for predicting the service life of the pipeline according to claim 1, wherein the performing a first detection operation on each group of the test pipelines in the plurality of groups of test pipelines to obtain the hydrostatic time and the burst strength value of each group of the test pipelines specifically comprises:
performing hydrostatic pressure test on each group of test pipelines in the plurality of groups of test pipelines, and detecting the hydrostatic pressure time of each group of test pipelines;
and carrying out a blasting test on the test pipelines after the hydrostatic test, and detecting the blasting strength value of each group of test pipelines.
3. The method for predicting the life of a pipeline according to claim 2, wherein the determining a first fitted equation between the hydrostatic time and the burst strength value specifically comprises:
determining the first fit equation according to the formula Ph ═ a × ln (t) + b,
wherein Ph is the burst strength value, t is the hydrostatic time, and a and b are constants.
4. The method for predicting the service life of the pipeline according to claim 1, wherein the second detection operation is performed on each group of test pipelines in the plurality of groups of test pipelines to obtain the soaking time and the failure strength value of the lining layer test sample corresponding to each group of test pipelines, and specifically comprises:
soaking the inner liner samples corresponding to each group of test pipelines in a corrosive medium, and detecting the soaking time of each group of inner liner samples;
stretching the soaked lining layer samples, and detecting the yield strength value of each group of lining layer samples;
and obtaining the failure strength value of each group of the inner liner samples according to the yield strength value.
5. The method for predicting the service life of the pipeline according to claim 4, wherein the step of soaking the lining layer samples corresponding to each group of the test pipelines in a corrosive medium and detecting the soaking time of each group of the lining layer samples specifically comprises the steps of:
pouring the corrosive medium into the soaking container;
soaking the lining layer sample in the corrosive medium and stirring the corrosive medium;
and after the inner liner sample reaches the corresponding soaking time, taking out the inner liner sample from the corrosive medium, and detecting the soaking time of the inner liner sample.
6. The pipeline life prediction method according to claim 4, wherein obtaining the failure strength value of each group of the lining layer samples according to the yield strength value specifically comprises:
determining the failure strength value of the inner liner sample according to a formula Pc-2 h Sigma/(D-h);
the inner liner comprises a sample, a sample layer and a sample layer, wherein Pc is the failure strength value, sigma is the yield strength value of the sample layer, D is the outer diameter of the inner liner layer, and h is the thickness of the inner liner layer.
7. The method according to claim 3, wherein the determining a second fit equation between the soak time and the failure intensity value specifically comprises:
determining the second fitting equation according to the formula Pc ═ c × ln (t) + d;
wherein Pc is the failure strength value, t is the soaking time, and c and d are constants.
8. The method for predicting the service life of the pipeline according to claim 7, wherein the equation of the soaking time and the intensity decay value is obtained according to a second fitted equation between the soaking time and the failure intensity value, and specifically comprises:
determining the soaking time and the intensity attenuation value equation according to the formula of delta Pc-e-ln (t),
wherein Δ Pc is the intensity decay value, t is the soak time, and e is a constant.
9. The method for predicting the service life of the pipeline according to claim 8, wherein the obtaining of the strength and time equation of the test pipeline under the combined action of the hydrostatic pressure and the corrosive medium according to the first fitted equation and the second fitted equation specifically comprises:
obtaining an equation of the strength and the time of the test pipeline under the combined action of hydrostatic pressure and a corrosive medium according to the first fitting equation and the equation of the soaking time and the strength attenuation value:
Pt＝Ph+α*ΔPc＝(a+α*e)*ln(t)+a*b，
the method comprises the steps of obtaining a strength value of a corrosion medium, obtaining a time value of the corrosion medium, obtaining Pt, obtaining Ph, obtaining Deltapc, obtaining alpha, obtaining a medium correlation coefficient, obtaining a constant, obtaining a time value of the corrosion medium, obtaining b time value of the corrosion medium, and obtaining a time value of the corrosion medium.
10. A pipeline life prediction apparatus comprising a processor and a memory, the memory having stored therein a computer program, the processor executing the computer program stored in the memory to cause the apparatus to perform the method of any one of claims 1 to 9.
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| CN104462806A (en) * | 2014-12-02 | 2015-03-25 | 中国石油天然气集团公司 | Non-metallic pipe life prediction method |
| CN111474108A (en) * | 2020-03-13 | 2020-07-31 | 中国石油天然气集团有限公司 | Service life prediction method for glass fiber reinforced plastic pipe |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN104462806A (en) * | 2014-12-02 | 2015-03-25 | 中国石油天然气集团公司 | Non-metallic pipe life prediction method |
| CN111474108A (en) * | 2020-03-13 | 2020-07-31 | 中国石油天然气集团有限公司 | Service life prediction method for glass fiber reinforced plastic pipe |
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