CN108760682B - Natural gas replacement parameter obtaining method and system and terminal equipment - Google Patents

Natural gas replacement parameter obtaining method and system and terminal equipment Download PDF

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CN108760682B
CN108760682B CN201810510529.6A CN201810510529A CN108760682B CN 108760682 B CN108760682 B CN 108760682B CN 201810510529 A CN201810510529 A CN 201810510529A CN 108760682 B CN108760682 B CN 108760682B
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concentration
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CN108760682A (en
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张金川
李沛
李中明
李振
魏晓亮
刘君兰
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HENAN INSTITUTE OF GEOLOGICAL SURVEY
China University of Geosciences Beijing
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China University of Geosciences Beijing
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    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
    • G01N21/25—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
    • G01N21/31—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry
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Abstract

The invention is applicable to the technical field of unconventional natural gas and discloses a method, a system and a terminal device for acquiring natural gas replacement parameters, wherein the method comprises the following steps: acquiring replacement experimental data of methane replaced by carbon dioxide; acquiring an absorbance curve of methane at a first moment, integrating the absorbance curve of methane at the first moment in a frequency domain to obtain a first integral area, and calculating the methane concentration at the first moment according to the first integral area and the replacement experiment data; calculating the methane concentration at the second moment by adopting the same method; calculating the displacement amount of methane in the first time period according to the methane concentration at the first moment, the methane concentration at the second moment and the displacement experiment data; the rate of displacement of methane in the first period of time is calculated from the amount of displacement of methane in the first period of time. The replacement experimental data obtained by the method has extremely high reliability and accuracy, so that the replacement parameters calculated according to the replacement experimental data have extremely high reliability and accuracy.

Description

Natural gas replacement parameter obtaining method and system and terminal equipment
Technical Field
The invention belongs to the technical field of unconventional natural gas, and particularly relates to a method, a system and terminal equipment for acquiring natural gas replacement parameters.
Background
Due to the huge reserves and potentials, the exploitation of unconventional natural gas resources is more and more emphasized, especially shale gas and coal bed gas. The shale gas and coal bed gas usually have free gas as main forms, but a considerable proportion (20-85%) of adsorbed gas exists, and methane is a main component of the shale gas and the coal bed gas and is generally more than 90%. At present, except for conventional pressure reduction desorption exploitation, a method for replacing adsorbed methane by injecting carbon dioxide is a novel method with great development prospect, and the recovery ratio of shale gas and coal bed gas can be effectively improved based on the method.
At present, the natural gas replacement parameters are mainly obtained by sampling and then analyzing by chromatography. The method indirectly acquires extremely limited component data in a discontinuous operation mode, lags behind the real-time process of replacing methane by carbon dioxide, and leads to larger analysis result errors.
Disclosure of Invention
In view of this, embodiments of the present invention provide a method, a system, and a terminal device for acquiring natural gas replacement parameters, so as to solve the problem in the prior art that an error of an analysis result is large because very limited component data is indirectly acquired in a discontinuous operation mode and the acquired component data lags behind a real-time process of replacing methane with carbon dioxide.
A first aspect of an embodiment of the present invention provides a method for obtaining natural gas replacement parameters, including:
acquiring replacement experimental data of methane replaced by carbon dioxide;
acquiring an absorbance curve of methane at a first moment, integrating the absorbance curve of methane at the first moment on a frequency domain to obtain a first integral area, and calculating the methane concentration at the first moment according to the first integral area and the replacement experiment data;
acquiring an absorbance curve of the methane at the second moment, integrating the absorbance curve of the methane at the second moment in a frequency domain to obtain a second integral area, and calculating the methane concentration at the second moment according to the second integral area and the replacement experiment data;
calculating the displacement amount of methane in a first time period according to the methane concentration at the first moment, the methane concentration at the second moment and the displacement experiment data, wherein the first time period is a time period between the first moment and the second moment;
the rate of displacement of methane in the first period of time is calculated from the amount of displacement of methane in the first period of time.
A second aspect of an embodiment of the present invention provides a natural gas replacement parameter acquisition system, including:
the first acquisition module is used for acquiring replacement experiment data of methane replaced by carbon dioxide;
the first methane concentration calculation module is used for acquiring an absorbance curve of methane at a first moment, integrating the absorbance curve of methane at the first moment in a frequency domain to obtain a first integral area, and calculating the methane concentration at the first moment according to the first integral area and the replacement experiment data;
the second methane concentration calculating module is used for acquiring an absorbance curve of the methane at the second moment, integrating the absorbance curve of the methane at the second moment in a frequency domain to obtain a second integral area, and calculating the methane concentration at the second moment according to the second integral area and the replacement experiment data;
the first displacement calculation module is used for calculating the displacement of methane in a first time period according to the methane concentration at the first moment, the methane concentration at the second moment and displacement experiment data, wherein the first time period is a time period from the first moment to the second moment;
and the replacement rate calculation module is used for calculating the replacement rate of the methane in the first time period according to the replacement amount of the methane in the first time period.
A third aspect of the embodiments of the present invention provides a terminal device, which includes a memory, a processor, and a computer program stored in the memory and executable on the processor, and when the processor executes the computer program, the steps of the natural gas substitution parameter acquiring method described above are implemented.
A fourth aspect of embodiments of the present invention provides a computer-readable storage medium storing a computer program which, when executed by one or more processors, performs the steps of the natural gas substitution parameter acquisition method as described above.
Compared with the prior art, the embodiment of the invention has the following beneficial effects: according to the embodiment of the invention, the replacement experiment data of the carbon dioxide replacing methane is firstly obtained, then the methane concentration at the first moment is calculated according to the methane absorbance curve at the first moment, the methane concentration at the second moment is calculated according to the methane absorbance curve at the second moment, then the replacement amount of the methane in the first time period is calculated according to the methane concentration at the first moment, the methane concentration at the second moment and the replacement experiment data, and finally the replacement rate of the methane in the first time period is calculated according to the replacement amount of the methane in the first time period. The method and the device can solve the problem that in the prior art, due to the fact that extremely limited component data are indirectly obtained in a discontinuous operation mode, and the obtained component data lag behind the real-time process of replacing methane with carbon dioxide, the analysis result error is large.
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In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the embodiments or the prior art descriptions will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without inventive exercise.
Fig. 1 is a schematic block diagram of a natural gas displacement parameter acquisition apparatus according to an embodiment of the present invention;
fig. 2 is a schematic flow chart of an implementation of a natural gas replacement parameter obtaining method according to an embodiment of the present invention;
FIG. 3 is a schematic block diagram of a natural gas substitution parameter acquisition system provided by an embodiment of the present invention;
fig. 4 is a schematic block diagram of a terminal device according to an embodiment of the present invention.
Detailed Description
In the following description, for purposes of explanation and not limitation, specific details are set forth, such as particular system structures, techniques, etc. in order to provide a thorough understanding of the embodiments of the present application. It will be apparent, however, to one skilled in the art that the present application may be practiced in other embodiments that depart from these specific details. In other instances, detailed descriptions of well-known systems, devices, circuits, and methods are omitted so as not to obscure the description of the present application with unnecessary detail.
It will be understood that the terms "comprises" and/or "comprising," when used in this specification and the appended claims, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.
It is also to be understood that the terminology used in the description of the present application herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used in the specification of the present application and the appended claims, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.
It should be further understood that the term "and/or" as used in this specification and the appended claims refers to and includes any and all possible combinations of one or more of the associated listed items.
As used in this specification and the appended claims, the term "if" may be interpreted contextually as "when", "upon" or "in response to a determination" or "in response to a detection". Similarly, the phrase "if it is determined" or "if a [ described condition or event ] is detected" may be interpreted contextually to mean "upon determining" or "in response to determining" or "upon detecting [ described condition or event ]" or "in response to detecting [ described condition or event ]".
In order to explain the technical means of the present invention, the following description will be given by way of specific examples.
Fig. 1 is a schematic diagram of a natural gas displacement parameter obtaining apparatus according to an embodiment of the present invention, and as shown in fig. 1, the apparatus may include: terminal equipment 11, signal generator 12, laser controller 13, laser emitter 14, sample chamber 15, detector and amplifier 16, lock-in amplifier 17.
The terminal device 11 sends a first control signal to the signal generator 12; the signal generator 12 sends out a modulation voltage signal to the laser controller 13 according to the first control signal, wherein the modulation voltage signal is generated by overlapping a low-frequency sawtooth signal and a high-frequency sine signal, and the low-frequency sawtooth signal is used for changing the wavelength of the laser signal emitted by the laser emitter 14; the terminal device 11 also sends a second control signal to the laser controller 13, and after receiving the second control signal, the laser controller 13 converts the modulation voltage signal into a modulation current signal and sends the modulation current signal to the laser transmitter 14; the laser emitter 14 adjusts the wavelength of the emitted laser signal according to the modulation current signal and emits the laser signal to the sample chamber 15; the laser signal is fully absorbed with carbon dioxide gas and methane gas in the sample chamber 15 to obtain an absorbed laser signal; the detector and amplifier 16 detects the absorbed laser signal, converts the absorbed laser signal into an absorbed electrical signal, and sends the absorbed electrical signal to the lock-in amplifier 17; the signal generator 12 may also send a reference signal to the lock-in amplifier 17, where the reference signal is a sine wave signal or a square wave signal, the lock-in amplifier 17 amplifies the absorbed electrical signal according to the reference signal to obtain a processed electrical signal, and sends the processed electrical signal to the terminal device 11; and the terminal equipment performs background subtraction and accumulation average processing on the processed electric signal to obtain an original spectrum absorption signal, then selects points on two sides of the original spectrum absorption signal to perform quadratic polynomial fitting to obtain an absorbance curve, and then performs the following calculation of the replacement parameters according to the absorbance curve.
The laser transmitter 14 includes two collimated laser diodes, wherein one of the collimated laser diodes transmits a laser signal for absorption with carbon dioxide gas, and the other collimated laser diode transmits a laser signal for absorption with methane gas. By querying the HITRAN database, 6336.24cm of carbon dioxide molecules were found-1The linear intensity of the absorption peak was approximately 1.609X 10-23cm/mol, selecting a wave band with the laser dominant wavelength of 1570nm by a corresponding collimation laser diode; the methane molecule has three absorption lines with very close distance in the vicinity of 1653.72nm, and the three absorption lines can be regarded as one line with the intensity being equal to that of the absorption line behind the intensity of the three absorption lines, and the sum of the intensities of the three absorption lines is 5.274 multiplied by 10-21cm/mol。
The lock-in amplifier 17 may be a 2f lock-in amplifier.
Further, the device may also include a pressure sensor, a temperature sensor, a heater, and the like. The pressure sensor is used for detecting the pressure of the sample chamber 15 and sending the detected pressure data to the terminal equipment 11; the temperature sensor detects the temperature of the sample chamber 15 and sends the detected temperature data to the terminal device 11; the heater is used for heating the sample chamber 15 to make the temperature in the sample chamber 15 reach the preset temperature.
Fig. 2 is a schematic flow chart of an implementation of the method for acquiring natural gas replacement parameters according to an embodiment of the present invention, and for convenience of description, only the parts related to the embodiment of the present invention are shown. The execution main body of the embodiment of the invention can be terminal equipment. As shown in fig. 2, the method may include the steps of:
step S201: and acquiring replacement experimental data of the methane replaced by the carbon dioxide.
In the embodiment of the invention, the experiment of replacing methane by carbon dioxide is carried out in a sample chamber under the conditions of constant temperature and constant pressure, namely the sample chamber keeps constant temperature and constant pressure all the time, the constant temperature is called as the experiment temperature, and the experiment temperature can be the actual reservoir temperature; this constant pressure is referred to as a first experimental pressure, which may be the actual reservoir pressure.
The course of the carbon dioxide displacement methane experiment was as follows: loading a sample in the sample chamber, wherein the sample can be a powdery or blocky shale sample or a powdery or blocky coal rock sample; heating the sample chamber to an experimental temperature, and keeping the experimental temperature unchanged; carrying out vacuum-pumping treatment on the sample chamber; starting a laser transmitter, and starting to acquire data after calibration; filling methane gas into the sample chamber at a first experiment pressure and balancing for a first preset time, wherein the first preset time can be 12 hours; after ensuring sufficient methane gas adsorption, slowly filling a certain amount of carbon dioxide gas into the sample chamber at the first experiment pressure, and balancing for a second preset time, wherein the second preset time can be 12 hours. The terminal device may continuously obtain the displacement experiment data in real time during the whole experiment process, and calculate displacement parameters, which may include, but are not limited to, one or more of the concentration of various gases in the sample chamber, the displacement amount, the displacement rate, the displacement efficiency, and the recovery ratio.
The displacement experiment data may include, but is not limited to, one or more of a first experiment pressure, an experiment temperature, a line intensity of absorption of carbon dioxide, a line intensity of absorption of methane, a laser light path length, a volume of remaining space in the sample chamber, a first compression factor.
Wherein the first experimental pressure can be obtained by a pressure sensor; the experimental temperature can be obtained by a temperature sensor; the absorption line intensity of carbon dioxide and the absorption line intensity of methane can be determined according to the experimental temperature, and can be determined by inquiring an HITRAN database; the laser optical path can be determined according to the transverse width of the sample chamber and the preset reflection times, a laser signal emitted by the laser emitter reaches the other side from one side of the sample chamber, the width between the two sides is called the transverse width of the sample chamber, and the transverse width of the sample chamber is multiplied by the preset reflection times to obtain the laser optical path; the volume of the remaining space in the sample chamber is obtained by subtracting the sample volume from the sample chamber volume, and the sample volume is obtained by dividing the sample mass by the sample density; the first compression factor is determined according to the first experiment pressure and the experiment temperature and can be obtained through table lookup.
Step S202: and acquiring an absorbance curve of the methane at the first moment, integrating the absorbance curve of the methane at the first moment in a frequency domain to obtain a first integral area, and calculating the methane concentration at the first moment according to the first integral area and the replacement experiment data.
When calculating the methane concentration, the dominant wavelength of the laser signal emitted by the laser emitter was 1653.72 nm.
In this step, the displacement experiment data may include the first experiment pressure, the absorption line intensity of methane, and the laser optical length.
According to Lambert-beer's law, a beam has an initial intensity of I0After the laser with the frequency f passes through the absorption medium, the calculation formula of the light intensity is as follows: i ═ I0exp[-∫l·kf(x)dx]Wherein I is the light intensity after absorption, l is the laser optical path, kfIs the spectral absorption coefficient of the absorbing medium. k is a radical offThe calculation formula of (2) is as follows:
Figure GDA0002303721420000071
Figure GDA0002303721420000072
wherein P is experimental pressure, XjIs the concentration of gas J, J is the total amount of gas, Si，jThe absorption line strength at a certain molecular energy level transition i of a gas j, which is temperature dependent, phii，jIs a linear function of the energy level transition i of a certain molecule of the gas j, the linear function being related to the pressure, and N represents the range of the energy level transition i from 1 to N. Since experiments are often carried out in high temperature and high pressure environments, the Voigt linear function is used to calculate the linear broadening, normalized by the form: integral multiple of phii，j(x, j) di ═ 1. The absorption frequency f for a particular test gas can be obtained from the three equations
Figure GDA0002303721420000073
Further obtain the
Figure GDA0002303721420000074
Wherein the content of the first and second substances,
Figure GDA0002303721420000075
a is the integrated area of the absorbance curve in the frequency domain. Therefore, in the experiment, the gas concentration of the gas can be calculated by acquiring the integrated area of the absorbance curve of the gas in the frequency domain, the experimental pressure, the line intensity of the absorption of the gas, and the laser light path length.
In the embodiment of the invention, the absorbance curve of methane at the first moment is firstly obtained, the absorbance curve of methane at the first moment is integrated on a frequency domain to obtain a first integrated area, and the methane concentration at the first moment is calculated according to the first integrated area, the first experiment pressure, the strong absorption line of methane and the laser optical path. The methane concentration at the first time is the free methane concentration at the first time.
Step S203: and acquiring an absorbance curve of the methane at the second moment, integrating the absorbance curve of the methane at the second moment in a frequency domain to obtain a second integral area, and calculating the methane concentration at the second moment according to the second integral area and the replacement experiment data.
The calculation formula for calculating the methane concentration at the second moment according to the second integral area and the displacement experiment data is as follows:
Figure GDA0002303721420000081
wherein, X2Is the methane concentration at the second moment, A2Is the second integral area, PoIs the first experimental pressure, S1The absorption line of methane is strong, and l is the laser optical path.
The methane concentration at the second time is the free methane concentration at the second time.
Step S204: and calculating the displacement amount of methane in a first time period according to the methane concentration at the first moment, the methane concentration at the second moment and the displacement experiment data, wherein the first time period is a time period between the first moment and the second moment.
In this step, the displacement experiment data may include a volume of remaining space in the sample chamber, a first experiment pressure, an experiment temperature, a first compression factor.
In the embodiment of the present invention, the displacement amount of methane in the first period of time refers to a volume amount of methane in a free state obtained by displacing methane in an adsorbed state with carbon dioxide gas at an experimental temperature and a first experimental pressure in an experiment for displacing methane with carbon dioxide. A greater displacement of methane in the first time period indicates a higher displacement intensity, indicating more desorption of adsorbed methane to free methane. The first time period is a time period between the first time and the second time.
Since carbon dioxide has a greater capacity for adsorbing organic matter than methane and lowers the partial pressure of methane, methane is desorbed for a short period of time and the displaced methane is in a free state. From the free equation of the gas state
Figure GDA0002303721420000082
Wherein the content of the first and second substances,
Figure GDA0002303721420000083
is the displacement amount of methane in the first period of time,
Figure GDA0002303721420000084
is the mass of methane, Z1Is a first compression factor, n is the amount of methane, R is the Avogastron constant, T is the experimental temperature, V is the volume of the remaining space in the sample chamber, X1Is the methane concentration at the first moment, X2Is the methane concentration at the second moment in time,
Figure GDA0002303721420000085
is the molar mass of methane molecules.
Step S205: the rate of displacement of methane in the first period of time is calculated from the amount of displacement of methane in the first period of time.
The displacement rate of methane in the first time period refers to how fast the carbon dioxide displaces methane in an experiment in which the carbon dioxide displaces methane at an experimental temperature and a first experimental pressure. The displacement amount of methane in the first time period divided by the first time period yields the displacement rate of methane in the first time period.
According to the embodiment of the invention, the replacement experiment data of the carbon dioxide replacing methane is firstly obtained, then the methane concentration at the first moment is calculated according to the methane absorbance curve at the first moment, the methane concentration at the second moment is calculated according to the methane absorbance curve at the second moment, then the replacement amount of the methane in the first time period is calculated according to the methane concentration at the first moment, the methane concentration at the second moment and the replacement experiment data, and finally the replacement rate of the methane in the first time period is calculated according to the replacement amount of the methane in the first time period. The method and the device can solve the problem that in the prior art, due to the fact that extremely limited component data are indirectly obtained in a discontinuous operation mode, and the obtained component data lag behind the real-time process of replacing methane with carbon dioxide, the analysis result error is large.
As another embodiment of the present invention, the displacement experiment data includes a first experiment pressure, an experiment temperature, a strong absorption line of methane, a laser optical path, a volume of a remaining space in the sample chamber, and a first compression factor;
the calculation formula for calculating the methane concentration at the first moment according to the first integrated area and the displacement experiment data is as follows:
Figure GDA0002303721420000091
wherein, X1Is the methane concentration at the first moment, A1Is the first integral area, PoIs the first experimental pressure, S1The absorption line of methane is strong, and l is the laser optical path;
the calculation formula for calculating the displacement amount of methane in the first time period according to the methane concentration at the first moment, the methane concentration at the second moment and the displacement experiment data is as follows:
Figure GDA0002303721420000092
wherein the content of the first and second substances,
Figure GDA0002303721420000093
is the displacement of methane in the first time period, Z1Is a first compression factor, R is the Avogastron constant, T is the experimental temperature, V is the volume of the remaining space in the sample chamber, X1Is the methane concentration at the first moment, X2Is the methane concentration at the second moment in time,
Figure GDA0002303721420000094
is the molar mass of methane molecules.
As another embodiment of the present invention, the method for obtaining natural gas replacement parameters further includes:
and monitoring a displacement experiment of the methane displaced by the carbon dioxide according to a tuned laser principle to obtain an absorbance curve of the methane at the first moment and an absorbance curve of the methane at the second moment.
In the embodiment of the present invention, the apparatus shown in fig. 1 is used to monitor a displacement experiment of methane displaced by carbon dioxide according to a tuned laser principle, so as to obtain an absorbance curve of methane at a first time and an absorbance curve of methane at a second time, and at the same time, obtain an absorbance curve of carbon dioxide at the first time and an absorbance curve of methane at the second time. For a detailed process, please refer to the description of fig. 1, which is not repeated herein.
As another embodiment of the present invention, the method for obtaining natural gas replacement parameters further includes:
acquiring an absorbance curve of the carbon dioxide at the first moment, integrating the absorbance curve of the carbon dioxide at the first moment in a frequency domain to obtain a third integral area, and calculating the concentration of the carbon dioxide at the first moment according to the third integral area and the replacement experiment data;
acquiring an absorbance curve of the carbon dioxide at the second moment, integrating the absorbance curve of the carbon dioxide at the second moment in a frequency domain to obtain a fourth integral area, and calculating the concentration of the carbon dioxide at the second moment according to the fourth integral area and the replacement experiment data;
calculating the replacement efficiency of methane in a first time period according to the methane concentration at the first moment, the methane concentration at the second moment, the carbon dioxide concentration at the first moment, the carbon dioxide concentration at the second moment and replacement experiment data;
the saturated adsorption capacity of methane before filling the sample chamber with carbon dioxide is obtained, and the first recovery factor of methane in the first time period is calculated according to the saturated adsorption capacity and the displacement capacity of methane in the first time period.
In an embodiment of the present invention, the displacement experiment data may include the first experiment pressure, the absorption line intensity of carbon dioxide, the laser optical path, and the volume of the remaining space in the sample chamber.
When calculating the carbon dioxide concentration, the dominant wavelength of the laser signal emitted by the laser emitter was 1570.0 nm.
And calculating the carbon dioxide concentration at the first moment according to the third integral area and the replacement experiment data by the following calculation formula:
Figure GDA0002303721420000101
wherein, X'1Is carbon dioxide concentration, A 'at the first moment'1Is the third integral area, S2The absorption line for carbon dioxide is strong.
The carbon dioxide concentration at the first time is the free carbon dioxide concentration at the first time.
And calculating the carbon dioxide concentration at the second moment according to the fourth integral area and the replacement experiment data by using a calculation formula as follows:
Figure GDA0002303721420000111
wherein, X'2Is carbon dioxide concentration, A 'at the first moment'2Is the third integrated area.
The carbon dioxide concentration at the second time is the free carbon dioxide concentration at the second time.
The displacement efficiency of methane in the first time period refers to the volume amount of free methane that can be displaced by a unit volume of carbon dioxide in a unit time at the experiment temperature and the first experiment pressure in an experiment of displacing methane by carbon dioxide. Efficiency of displacement of methane in a first time period
Figure GDA0002303721420000112
The calculation formula of (2) is as follows:
Figure GDA0002303721420000113
wherein the content of the first and second substances,
Figure GDA0002303721420000114
is the mass of the methane,
Figure GDA0002303721420000115
is the mass of the carbon dioxide,
Figure GDA0002303721420000116
is the carbon dioxide molecular molar mass and t is the first time period.
The first recovery factor of methane in the first time period refers to the ratio of the amount of methane in the adsorption state displaced by the carbon dioxide gas filled in the experiment in the first time period to the initial total amount of methane at the experiment temperature and the first experiment pressure in the experiment of replacing methane by carbon dioxide. Wherein, if the sample is coal rock, the first time period can be 12 hours.
The saturated adsorption amount of methane prior to charging the sample chamber with carbon dioxide and the third experimental pressure at which methane is saturated adsorbed prior to charging the sample chamber with carbon dioxide, which is used thereafter, are both values that have been obtained prior to the displacement experiment, and which are fixed values in the case of sample determination, and which can be calculated according to the isothermal adsorption experiment test, Langmuir (Langmuir) equation.
As still another embodiment of the present invention, a calculation formula for calculating the methane displacement efficiency in the first time period based on the methane concentration at the first time, the methane concentration at the second time, the carbon dioxide concentration at the first time, the carbon dioxide concentration at the second time, and the displacement experiment data is:
Figure GDA0002303721420000117
wherein the content of the first and second substances,
Figure GDA0002303721420000118
is the efficiency of the displacement of methane in the first time period, V is the volume of the remaining space in the sample chamber, X2Is the methane concentration at the second moment, X1Is the methane concentration, X 'at the first moment'2Is carbon dioxide concentration, X 'at the second moment'1Is the concentration of carbon dioxide at the first moment,
Figure GDA0002303721420000119
is the molar mass of the methane molecules,
Figure GDA00023037214200001110
is the molar mass of carbon dioxide molecules, and t is a first time period;
the calculation formula for calculating the first recovery factor of methane in the first time period according to the saturated adsorption amount and the displacement amount of methane in the first time period is as follows:
Figure GDA0002303721420000121
wherein the content of the first and second substances,
Figure GDA0002303721420000122
for the purpose of the first recovery factor,
Figure GDA0002303721420000123
is the displacement of methane in the first time period, VLThe amount of the adsorbed substance was saturated.
As another embodiment of the present invention, the displacement experiment data includes a first experiment pressure, an experiment temperature, a first compression factor, a volume of a remaining space in the sample chamber;
the method for acquiring the natural gas replacement parameters further comprises the following steps:
acquiring a second experiment pressure and a third experiment pressure when methane is saturated and adsorbed before carbon dioxide is filled into the sample chamber, and acquiring a second compression factor according to the second experiment pressure and the experiment temperature;
calculating the decompression desorption amount of the methane when the first experiment pressure is reduced to the second experiment pressure according to the first experiment pressure, the second experiment pressure, the third experiment pressure and the saturated adsorption amount;
calculating a carbon dioxide concentration at a first experimental pressure and a carbon dioxide concentration at a second experimental pressure;
calculating the displacement amount of methane when the pressure is reduced from the first experiment pressure to the second experiment pressure according to the concentration of the carbon dioxide under the first experiment pressure, the concentration of the carbon dioxide under the second experiment pressure, the volume of the residual space in the sample chamber, the first compression factor, the second compression factor, the first experiment pressure, the second experiment pressure, the experiment temperature and the preset displacement ratio of the carbon dioxide to the methane;
and calculating the second recovery factor of the methane according to the decompression desorption amount of the methane, the displacement amount of the methane when the first experiment pressure is reduced to the second experiment pressure, the saturated adsorption amount and the displacement amount of the methane in the first time period.
In the embodiment of the invention, in the experiment of replacing methane with carbon dioxide, the experiment is monitored in the process of reducing the pressure from the first experiment pressure to the second experiment pressure under the condition that the experiment temperature is kept unchanged.
The second recovery factor of methane is the ratio of the sum of the depressurized desorption amount of methane and the displacement amount of methane displaced by carbon dioxide to the total amount of methane at the beginning when the first experimental pressure is reduced to the second experimental pressure at the experimental temperature. The second experimental pressure may be a depletion pressure.
The carbon dioxide concentration at the first experimental pressure and the carbon dioxide concentration at the second experimental pressure are calculated as follows: acquiring an absorbance curve of the carbon dioxide at the first experiment pressure, integrating the absorbance curve of the carbon dioxide at the first experiment pressure in a frequency domain to obtain a fifth integral area, and calculating the concentration of the carbon dioxide at the first experiment pressure according to the fifth integral area, the first experiment pressure, the strong absorption line of the carbon dioxide and the optical path of the laser; and acquiring an absorbance curve of the carbon dioxide at the second experiment pressure, integrating the absorbance curve of the carbon dioxide at the second experiment pressure in a frequency domain to obtain a sixth integral area, and calculating the concentration of the carbon dioxide at the second experiment pressure according to the sixth integral area, the second experiment pressure, the intensity of an absorption line of the carbon dioxide and the optical path of the laser.
The predetermined carbon dioxide to methane displacement ratio may be 1: 1.
As still another embodiment of the present invention, the calculation formula for calculating the depressurized desorption amount of methane when the pressure is decreased from the first experimental pressure to the second experimental pressure based on the first experimental pressure, the second experimental pressure, the third experimental pressure, and the saturated adsorption amount is:
Figure GDA0002303721420000131
wherein, DeltaV is the decompression desorption amount of methane,VLto saturate the adsorption capacity, PoIs the first experimental pressure, PfIs the second experimental pressure, PLIs the third experimental pressure;
calculating the displacement amount of methane when the pressure is reduced from the first experiment pressure to the second experiment pressure according to the carbon dioxide concentration under the first experiment pressure, the carbon dioxide concentration under the second experiment pressure, the volume of the residual space in the sample chamber, the first compression factor, the second compression factor, the first experiment pressure, the second experiment pressure, the experiment temperature and the preset displacement ratio of the carbon dioxide to the methane, wherein the calculation formula comprises the following steps:
Figure GDA0002303721420000132
wherein the content of the first and second substances,
Figure GDA0002303721420000133
s is a preset replacement ratio of carbon dioxide to methane, and Z is the replacement amount of methane when the first experiment pressure is reduced to the second experiment pressure1Is a first compression factor, R is the Avogastron constant, T is the experimental temperature, V is the volume of the remaining space in the sample chamber, XoIs the concentration of carbon dioxide at the first experimental pressure,
Figure GDA0002303721420000134
is the molar mass of carbon dioxide molecules, Z2Is the second compression factor, XfIs the carbon dioxide concentration at the second experimental pressure;
the calculation formula for calculating the second recovery factor of methane according to the depressurized desorption amount of methane, the displacement amount of methane when the pressure is reduced from the first experiment pressure to the second experiment pressure, the saturated adsorption amount and the displacement amount of methane in the first time period is as follows:
Figure GDA0002303721420000141
wherein the content of the first and second substances,
Figure GDA0002303721420000142
for the purpose of the second recovery factor,
Figure GDA0002303721420000143
is the displacement amount of methane in the first period of time.
In the embodiment of the invention, based on the principle of tuning laser, and combined with the conventional real-time monitoring means of temperature and pressure, the continuous and dynamic data monitoring and acquisition of gas adsorption, desorption, gas replacement and different steady-state change data can be carried out under the conditions of temperature and pressure environment change and injected gas component change, so as to achieve the effect of obtaining synchronous experimental test and data output.
In the embodiment of the invention, the tuned laser principle is applied to the experiment of replacing methane with carbon dioxide, and the principle has the characteristics of unique selectivity, high sensitivity (reaching ppm-ppt magnitude) and continuous real-time monitoring aiming at specific gas, so that basic data used in the embodiment of the invention has extremely high reliability and accuracy, the obtained calculation result is necessarily more reliable and close to reality, and the accurate determination of the recovery ratio and the accurate accounting of the resource reserves in the shale gas replacement exploitation evaluation process are facilitated.
The embodiment of the invention provides a high-precision calculation method for the displacement amount, the displacement rate, the displacement efficiency and the recovery ratio of different components, and further more dynamic parameters in the temperature and pressure change process can be obtained according to the parameters, such as the gas change along with the pressure/temperature diffusion under the isothermal/isobaric conditions and the like.
The basic data in the embodiment of the invention is directly, comprehensively and accurately acquired, the experiment traces back the temperature and pressure conditions of the original reservoir as much as possible, and the defects of result deviation and separation from the actual field caused by the calculation of different mathematical models in a conventional method (such as a molecular theory and a numerical simulation method) are avoided to a great extent, so that the method has firm data base, a rigorous calculation reasoning process and a reliable calculation result.
Because the Coal rock is the organic hydrocarbon source rich rock, the Coal Bed has larger gas adsorption ratio, and the temperature and pressure characteristic and the adsorption and desorption characteristic of a Coal reservoir can be combined, the method provided by the embodiment of the invention is applied to the field of Coal Bed gas, so that the experimental and theoretical research of the technology for improving the Recovery ratio of the Coal Bed gas (ECBM) is promoted.
It should be noted that, all the examples in the above embodiments are only for explaining the technical solutions of the present invention, and are not used to limit the present invention.
It should be understood that, the sequence numbers of the steps in the foregoing embodiments do not imply an execution sequence, and the execution sequence of each process should be determined by its function and inherent logic, and should not constitute any limitation to the implementation process of the embodiments of the present invention.
Fig. 3 is a schematic block diagram of a natural gas displacement parameter acquisition system according to an embodiment of the present invention, and for convenience of explanation, only the portions related to the embodiment of the present invention are shown.
In the embodiment of the present invention, the natural gas replacement parameter acquiring system 3 includes:
the first obtaining module 31 is configured to obtain replacement experiment data of methane replaced with carbon dioxide;
the first methane concentration calculation module 32 is configured to obtain an absorbance curve of methane at a first time, integrate the absorbance curve of methane at the first time in a frequency domain to obtain a first integrated area, and calculate a methane concentration at the first time according to the first integrated area and the replacement experiment data;
the second methane concentration calculating module 33 is configured to obtain an absorbance curve of methane at the second time, integrate the absorbance curve of methane at the second time in a frequency domain to obtain a second integrated area, and calculate a methane concentration at the second time according to the second integrated area and the replacement experiment data;
the first displacement calculation module 34 is configured to calculate a displacement of methane in a first time period according to the methane concentration at the first time, the methane concentration at the second time, and the displacement experiment data, where the first time period is a time period between the first time and the second time;
and a replacement rate calculation module 35, configured to calculate a replacement rate of methane in the first time period according to the replacement amount of methane in the first time period.
Optionally, the displacement experiment data includes a first experiment pressure, an experiment temperature, an absorption line intensity of methane, a laser optical path, a volume of a remaining space in the sample chamber, and a first compression factor;
in the first methane concentration calculation module 32, the calculation formula for calculating the methane concentration at the first time point according to the first integrated area and the displacement experiment data is:
Figure GDA0002303721420000151
wherein, X1Is the methane concentration at the first moment, A1Is the first integral area, PoIs the first experimental pressure, S1The absorption line of methane is strong, and l is the laser optical path;
in the first displacement amount calculation module 34, a calculation formula for calculating the displacement amount of methane in the first time period according to the methane concentration at the first time, the methane concentration at the second time and the displacement experiment data is as follows:
Figure GDA0002303721420000161
wherein the content of the first and second substances,
Figure GDA0002303721420000162
is the displacement of methane in the first time period, Z1Is a first compression factor, R is the Avogastron constant, T is the experimental temperature, V is the volume of the remaining space in the sample chamber, X1Is the methane concentration at the first moment, X2Is the methane concentration at the second moment in time,
Figure GDA0002303721420000163
is the molar mass of methane molecules.
Optionally, the natural gas replacement parameter acquiring system 3 further includes:
and the monitoring module is used for monitoring a displacement experiment of the methane displaced by the carbon dioxide according to the tuned laser principle to obtain an absorbance curve of the methane at the first moment and an absorbance curve of the methane at the second moment.
Optionally, the natural gas replacement parameter acquiring system 3 further includes:
the first carbon dioxide concentration calculation module is used for acquiring an absorbance curve of the carbon dioxide at the first moment, integrating the absorbance curve of the carbon dioxide at the first moment in a frequency domain to obtain a third integral area, and calculating the carbon dioxide concentration at the first moment according to the third integral area and the replacement experiment data;
the second carbon dioxide concentration calculation module is used for acquiring an absorbance curve of the carbon dioxide at the second moment, integrating the absorbance curve of the carbon dioxide at the second moment in a frequency domain to obtain a fourth integral area, and calculating the carbon dioxide concentration at the second moment according to the fourth integral area and the replacement experiment data;
the displacement efficiency calculation module is used for calculating the displacement efficiency of methane in a first time period according to the methane concentration at the first moment, the methane concentration at the second moment, the carbon dioxide concentration at the first moment, the carbon dioxide concentration at the second moment and displacement experiment data;
and the first recovery ratio calculation module is used for acquiring the saturated adsorption quantity of the methane before the sample chamber is filled with the carbon dioxide and calculating the first recovery ratio of the methane in the first time period according to the saturated adsorption quantity and the displacement quantity of the methane in the first time period.
Optionally, in the replacement efficiency calculation module, a calculation formula for calculating the replacement efficiency of methane in the first time period according to the methane concentration at the first time, the methane concentration at the second time, the carbon dioxide concentration at the first time, the carbon dioxide concentration at the second time, and the replacement experiment data is as follows:
Figure GDA0002303721420000164
wherein the content of the first and second substances,
Figure GDA0002303721420000171
is the efficiency of the displacement of methane in the first time period, V is the volume of the remaining space in the sample chamber, X2Is the second moment of timeConcentration of methane, X1Is the methane concentration, X 'at the first moment'2Is carbon dioxide concentration, X 'at the second moment'1Is the concentration of carbon dioxide at the first moment,
Figure GDA0002303721420000172
is the molar mass of the methane molecules,
Figure GDA0002303721420000173
is the molar mass of carbon dioxide molecules, and t is a first time period;
in the first recovery factor calculating module, a calculation formula for calculating the first recovery factor of methane in the first time period according to the saturated adsorption amount and the displacement amount of methane in the first time period is as follows:
Figure GDA0002303721420000174
wherein the content of the first and second substances,
Figure GDA0002303721420000175
for the purpose of the first recovery factor,
Figure GDA0002303721420000176
is the displacement of methane in the first time period, VLThe amount of the adsorbed substance was saturated.
Optionally, the displacement experiment data comprises a first experiment pressure, an experiment temperature, a first compression factor, a volume of remaining space in the sample chamber;
the natural gas replacement parameter acquiring system 3 further includes:
the second acquisition module is used for acquiring a second experiment pressure and a third experiment pressure during methane saturation adsorption before carbon dioxide is filled into the sample chamber, and acquiring a second compression factor according to the second experiment pressure and the experiment temperature;
the reduced pressure desorption amount calculation module is used for calculating the reduced pressure desorption amount of the methane when the first experiment pressure is reduced to the second experiment pressure according to the first experiment pressure, the second experiment pressure, the third experiment pressure and the saturated adsorption amount;
a third carbon dioxide concentration calculation module for calculating a carbon dioxide concentration at the first experimental pressure and a carbon dioxide concentration at the second experimental pressure;
the second displacement amount calculation module is used for calculating the displacement amount of methane when the pressure is reduced from the first experiment pressure to the second experiment pressure according to the concentration of the carbon dioxide under the first experiment pressure, the concentration of the carbon dioxide under the second experiment pressure, the volume of the residual space in the sample chamber, the first compression factor, the second compression factor, the first experiment pressure, the second experiment pressure, the experiment temperature and the preset displacement ratio of the carbon dioxide to the methane;
and the second recovery ratio calculation module is used for calculating the second recovery ratio of the methane according to the depressurization desorption amount of the methane, the replacement amount of the methane when the pressure is reduced from the first experiment pressure to the second experiment pressure, the saturated adsorption amount and the replacement amount of the methane in the first time period.
Optionally, in the reduced-pressure desorption amount calculation module, a calculation formula for calculating the reduced-pressure desorption amount of methane when the methane is reduced from the first experiment pressure to the second experiment pressure according to the first experiment pressure, the second experiment pressure, the third experiment pressure and the saturated adsorption amount is as follows:
Figure GDA0002303721420000181
wherein, DeltaV is the decompression desorption amount of methane, VLTo saturate the adsorption capacity, PoIs the first experimental pressure, PfIs the second experimental pressure, PLIs the third experimental pressure;
in the second displacement calculation module, a calculation formula for calculating the displacement of methane when the pressure is reduced from the first experiment pressure to the second experiment pressure according to the carbon dioxide concentration at the first experiment pressure, the carbon dioxide concentration at the second experiment pressure, the volume of the residual space in the sample chamber, the first compression factor, the second compression factor, the first experiment pressure, the second experiment pressure, the experiment temperature and the preset displacement ratio of carbon dioxide to methane is as follows:
Figure GDA0002303721420000182
wherein the content of the first and second substances,
Figure GDA0002303721420000183
s is a preset replacement ratio of carbon dioxide to methane, and Z is the replacement amount of methane when the first experiment pressure is reduced to the second experiment pressure1Is a first compression factor, R is the Avogastron constant, T is the experimental temperature, V is the volume of the remaining space in the sample chamber, XoIs the concentration of carbon dioxide at the first experimental pressure,
Figure GDA0002303721420000184
is the molar mass of carbon dioxide molecules, Z2Is the second compression factor, XfIs the carbon dioxide concentration at the second experimental pressure;
in the second recovery ratio calculation module, a calculation formula for calculating the second recovery ratio of methane according to the depressurized desorption amount of methane, the displacement amount of methane when the pressure is reduced from the first experiment pressure to the second experiment pressure, the saturated adsorption amount and the displacement amount of methane in the first time period is as follows:
Figure GDA0002303721420000185
wherein the content of the first and second substances,
Figure GDA0002303721420000186
for the purpose of the second recovery factor,
Figure GDA0002303721420000187
is the displacement amount of methane in the first period of time.
It is obvious to those skilled in the art that, for convenience and simplicity of description, the foregoing division of the functional units and modules is merely used as an example, and in practical applications, the above function distribution may be performed by different functional units and modules as needed, that is, the internal structure of the natural gas replacement parameter acquiring system is divided into different functional units or modules to perform all or part of the above described functions. Each functional unit and module in the embodiments may be integrated in one processing unit, or each unit may exist alone physically, or two or more units are integrated in one unit, and the integrated unit may be implemented in a form of hardware, or in a form of software functional unit. In addition, specific names of the functional units and modules are only for convenience of distinguishing from each other, and are not used for limiting the protection scope of the present application. The specific working processes of the units and modules in the above-mentioned apparatus may refer to the corresponding processes in the foregoing method embodiments, and are not described herein again.
Fig. 4 is a schematic block diagram of a terminal device according to an embodiment of the present invention. As shown in fig. 4, the terminal device 11 of this embodiment includes: one or more processors 110, a memory 111, and a computer program 112 stored in the memory 111 and executable on the processors 110. The processor 110, when executing the computer program 112, implements the steps in the above-described embodiments of the natural gas substitution parameter acquisition method, such as the steps S201 to S205 shown in fig. 2. Alternatively, the processor 110, when executing the computer program 112, implements the functions of the modules/units in the above-described embodiments of the natural gas substitution parameter acquisition system, such as the functions of the modules 31 to 35 shown in fig. 3.
Illustratively, the computer program 112 may be partitioned into one or more modules/units that are stored in the memory 111 and executed by the processor 110 to accomplish the present application. The one or more modules/units may be a series of computer program instruction segments capable of performing specific functions, which are used for describing the execution process of the computer program 112 in the terminal device 11. For example, the computer program 112 may be divided into a first acquisition module, a first methane concentration calculation module, a second methane concentration calculation module, a first displacement amount calculation module, and a displacement rate calculation module.
The first acquisition module is used for acquiring replacement experiment data of methane replaced by carbon dioxide;
the first methane concentration calculation module is used for acquiring an absorbance curve of methane at a first moment, integrating the absorbance curve of methane at the first moment in a frequency domain to obtain a first integral area, and calculating the methane concentration at the first moment according to the first integral area and the replacement experiment data;
the second methane concentration calculating module is used for acquiring an absorbance curve of the methane at the second moment, integrating the absorbance curve of the methane at the second moment in a frequency domain to obtain a second integral area, and calculating the methane concentration at the second moment according to the second integral area and the replacement experiment data;
the first displacement calculation module is used for calculating the displacement of methane in a first time period according to the methane concentration at the first moment, the methane concentration at the second moment and displacement experiment data, wherein the first time period is a time period from the first moment to the second moment;
and the replacement rate calculation module is used for calculating the replacement rate of the methane in the first time period according to the replacement amount of the methane in the first time period.
Other modules or units can refer to the description of the embodiment shown in fig. 3, and are not described again here.
The terminal device can be a desktop computer, a notebook, a palm computer, a cloud server and other computing devices. The terminal device 11 includes, but is not limited to, a processor 110 and a memory 111. It will be understood by those skilled in the art that fig. 4 is only one example of a terminal device, and does not constitute a limitation to terminal device 11, and may include more or less components than those shown, or combine some components, or different components, for example, terminal device 11 may also include an input device, an output device, a network access device, a bus, etc.
The Processor 110 may be a Central Processing Unit (CPU), other general purpose Processor, a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA) or other Programmable logic device, discrete Gate or transistor logic device, discrete hardware component, or the like. A general purpose processor may be a microprocessor or the processor may be any conventional processor or the like.
The storage 111 may be an internal storage unit of the terminal device, such as a hard disk or a memory of the terminal device. The memory 111 may also be an external storage device of the terminal device, such as a plug-in hard disk, a Smart Media Card (SMC), a Secure Digital (SD) Card, a Flash memory Card (Flash Card), and the like, which are provided on the terminal device. Further, the memory 111 may also include both an internal storage unit of the terminal device and an external storage device. The memory 111 is used for storing the computer program 112 and other programs and data required by the terminal device. The memory 111 may also be used to temporarily store data that has been output or is to be output.
In the above embodiments, the descriptions of the respective embodiments have respective emphasis, and reference may be made to the related descriptions of other embodiments for parts that are not described or illustrated in a certain embodiment.
Those of ordinary skill in the art will appreciate that the various illustrative elements and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware or combinations of computer software and electronic hardware. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the implementation. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present application.
In the embodiments provided in the present application, it should be understood that the disclosed natural gas replacement parameter acquisition system and method may be implemented in other ways. For example, the above-described embodiments of the natural gas substitution parameter acquisition system are merely illustrative, and for example, the division of the modules or units is only one logical functional division, and other divisions may be realized in practice, for example, a plurality of units or components 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 units, and may be in an electrical, mechanical or other form.
The units described as separate parts may or may not be physically separate, and parts displayed as units 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 units can be selected according to actual needs to achieve the purpose of the solution of the embodiment.
In addition, functional units in the embodiments of the present application may be integrated into one processing unit, or each unit may exist alone physically, or two or more units are integrated into one unit. The integrated unit can be realized in a form of hardware, and can also be realized in a form of a software functional unit.
The integrated modules/units, if implemented in the form of software functional units and sold or used as separate products, may be stored in a computer readable storage medium. Based on such understanding, all or part of the flow in the method of the embodiments described above can be realized by a computer program, which can be stored in a computer-readable storage medium and can realize the steps of the embodiments of the methods described above when the computer program is executed by a processor. Wherein the computer program comprises computer program code, which may be in the form of source code, object code, an executable file or some intermediate form, etc. The computer-readable medium may include: any entity or device capable of carrying the computer program code, recording medium, usb disk, removable hard disk, magnetic disk, optical disk, computer Memory, Read-Only Memory (ROM), Random Access Memory (RAM), electrical carrier wave signals, telecommunications signals, software distribution medium, and the like. It should be noted that the computer readable medium may contain other components which may be suitably increased or decreased as required by legislation and patent practice in jurisdictions, for example, in some jurisdictions, computer readable media which may not include electrical carrier signals and telecommunications signals in accordance with legislation and patent practice.
The above-mentioned embodiments are only used for illustrating the technical solutions of the present application, and not for limiting the same; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; such modifications and substitutions do not substantially depart from the spirit and scope of the embodiments of the present application and are intended to be included within the scope of the present application.

Claims (10)

1. A natural gas replacement parameter acquisition method is characterized by comprising the following steps:
acquiring replacement experimental data of methane replaced by carbon dioxide;
acquiring an absorbance curve of methane at a first moment, integrating the absorbance curve of methane at the first moment on a frequency domain to obtain a first integral area, and calculating the methane concentration at the first moment according to the first integral area and the replacement experiment data;
acquiring an absorbance curve of methane at a second moment, integrating the absorbance curve of methane at the second moment in a frequency domain to obtain a second integral area, and calculating the methane concentration at the second moment according to the second integral area and the replacement experiment data;
calculating the displacement amount of methane in a first time period according to the methane concentration at the first moment, the methane concentration at the second moment and the displacement experiment data, wherein the first time period is a time period between the first moment and the second moment;
and calculating the replacement rate of the methane in the first time period according to the replacement amount of the methane in the first time period.
2. The natural gas displacement parameter acquisition method according to claim 1, wherein the displacement experiment data includes a first experiment pressure, an experiment temperature, an absorption line intensity of methane, a laser optical length, a volume of a remaining space in the sample chamber, a first compression factor;
the calculation formula for calculating the methane concentration at the first moment according to the first integral area and the displacement experiment data is as follows:
Figure FDA0002303721410000011
wherein, X1Is the methane concentration at the first moment, A1Is the first integral area, PoIs the first experimental pressure, S1The line intensity of the absorption line of the methane is strong, and l is the optical path of the laser;
the calculation formula for calculating the displacement amount of methane in the first time period according to the methane concentration at the first moment, the methane concentration at the second moment and the displacement experiment data is as follows:
Figure FDA0002303721410000021
wherein the content of the first and second substances,
Figure FDA0002303721410000022
is the displacement of methane in the first period of time, Z1For the first compression factor, R is an Avogastro constant, T is the experimental temperature, V is the volume of the remaining space in the sample chamber, X1Is the methane concentration, X, at said first moment2Is the methane concentration at the second time instant,
Figure FDA0002303721410000023
is the molar mass of methane molecules.
3. The natural gas substitution parameter acquisition method as claimed in claim 1, further comprising:
and monitoring a displacement experiment of the methane displaced by the carbon dioxide according to a tuned laser principle to obtain an absorbance curve of the methane at the first moment and an absorbance curve of the methane at the second moment.
4. The natural gas substitution parameter acquisition method as claimed in claim 1, further comprising:
acquiring an absorbance curve of the carbon dioxide at a first moment, integrating the absorbance curve of the carbon dioxide at the first moment on a frequency domain to obtain a third integral area, and calculating the concentration of the carbon dioxide at the first moment according to the third integral area and the replacement experiment data;
acquiring an absorbance curve of the carbon dioxide at a second moment, integrating the absorbance curve of the carbon dioxide at the second moment on a frequency domain to obtain a fourth integral area, and calculating the concentration of the carbon dioxide at the second moment according to the fourth integral area and the replacement experiment data;
calculating the replacement efficiency of methane in the first time period according to the methane concentration at the first moment, the methane concentration at the second moment, the carbon dioxide concentration at the first moment, the carbon dioxide concentration at the second moment and the replacement experiment data;
and acquiring the saturated adsorption quantity of the methane before filling the carbon dioxide into the sample chamber, and calculating the first recovery factor of the methane in the first time period according to the saturated adsorption quantity and the displacement quantity of the methane in the first time period.
5. The natural gas substitution parameter acquisition method as claimed in claim 4, wherein the substitution experiment data includes a first experiment pressure, an experiment temperature, a volume of a remaining space in the sample chamber, and a first compression factor;
the calculation formula for calculating the methane replacement efficiency in the first time period according to the methane concentration at the first moment, the methane concentration at the second moment, the carbon dioxide concentration at the first moment, the carbon dioxide concentration at the second moment and the replacement experiment data is as follows:
Figure FDA0002303721410000031
wherein the content of the first and second substances,
Figure FDA0002303721410000032
for the efficiency of the displacement of methane in said first period of time, V is the volume of the remaining space in the sample chamber, X2Is the methane concentration, X, at said second moment1Is the methane concentration, X 'at the first moment'2Is the carbon dioxide concentration, X 'at the second moment'1Is the concentration of carbon dioxide at the first moment,
Figure FDA0002303721410000033
is the molar mass of the methane molecules,
Figure FDA0002303721410000034
is the molar mass of carbon dioxide molecules, and t is the first time period;
the calculation formula for calculating the first recovery factor of methane in the first time period according to the saturated adsorption capacity and the displacement quantity of methane in the first time period is as follows:
Figure FDA0002303721410000035
wherein the content of the first and second substances,
Figure FDA0002303721410000036
for the purpose of the first recovery factor,
Figure FDA0002303721410000037
is the displacement of methane in the first time period, VLIs the saturated adsorption capacity;
the calculation formula of the displacement amount of methane in the first time period is as follows:
Figure FDA0002303721410000038
wherein Z is1Is the first compression factor, R is the Avogastron constant, T is the experimental temperature, P isoIs the first experimental pressure.
6. The natural gas substitution parameter acquisition method as claimed in claim 4, wherein the substitution experiment data includes a first experiment pressure, an experiment temperature, a first compression factor, a volume of a remaining space in the sample chamber;
the method further comprises the following steps:
acquiring a second experiment pressure and a third experiment pressure during methane saturation adsorption before filling carbon dioxide into the sample chamber, and acquiring a second compression factor according to the second experiment pressure and the experiment temperature;
calculating the decompression desorption amount of the methane when the first experiment pressure is reduced to the second experiment pressure according to the first experiment pressure, the second experiment pressure, the third experiment pressure and the saturated adsorption amount;
calculating a carbon dioxide concentration at the first experimental pressure and a carbon dioxide concentration at the second experimental pressure;
calculating the displacement amount of methane when the first experiment pressure is reduced to the second experiment pressure according to the carbon dioxide concentration at the first experiment pressure, the carbon dioxide concentration at the second experiment pressure, the volume of the residual space in the sample chamber, the first compression factor, the second compression factor, the first experiment pressure, the second experiment pressure, the experiment temperature and the preset displacement ratio of carbon dioxide to methane;
and calculating a second recovery factor of the methane according to the depressurization desorption amount of the methane, the replacement amount of the methane when the pressure is reduced from the first experiment pressure to the second experiment pressure, the saturation adsorption amount and the replacement amount of the methane in the first time period.
7. The method for obtaining natural gas substitution parameters according to claim 6, wherein the calculation formula for calculating the depressurization desorption amount of methane when the pressure is reduced from the first experimental pressure to the second experimental pressure based on the first experimental pressure, the second experimental pressure, the third experimental pressure, and the saturation adsorption amount is:
Figure FDA0002303721410000041
wherein Δ V is the desorption amount of methane by depressurization, VLFor the saturated adsorption amount, PoIs the first experimental pressure, PfIs the second experimental pressure, PLIs the third experimental pressure;
the calculation formula for calculating the displacement amount of methane when the pressure is reduced from the first experiment pressure to the second experiment pressure according to the carbon dioxide concentration at the first experiment pressure, the carbon dioxide concentration at the second experiment pressure, the volume of the residual space in the sample chamber, the first compression factor, the second compression factor, the first experiment pressure, the second experiment pressure, the experiment temperature and the preset displacement ratio of carbon dioxide to methane is as follows:
Figure FDA0002303721410000042
wherein the content of the first and second substances,
Figure FDA0002303721410000043
is the displacement amount of methane when the pressure is reduced from the first experiment pressure to the second experiment pressure, S is the preset displacement ratio of carbon dioxide to methane, Z1For the first compression factor, R is an Avogastro constant, T is the experimental temperature, V is the volume of the remaining space in the sample chamber, XoIs dioxygen at the first experimental pressureThe concentration of the carbon is changed,
Figure FDA0002303721410000051
is the molar mass of carbon dioxide molecules, Z2Is said second compression factor, XfIs the carbon dioxide concentration at the second experimental pressure;
the calculation formula for calculating the second recovery factor of methane according to the depressurized desorption amount of methane, the displacement amount of methane when the pressure is reduced from the first experiment pressure to the second experiment pressure, the saturated adsorption amount and the displacement amount of methane in the first time period is as follows:
Figure FDA0002303721410000052
wherein the content of the first and second substances,
Figure FDA0002303721410000053
for the purpose of the second recovery factor,
Figure FDA0002303721410000054
is the displacement of methane in the first time period;
the calculation formula of the displacement amount of methane in the first time period is as follows:
Figure FDA0002303721410000055
wherein, X1Is the methane concentration, X, at said first moment2Is the methane concentration at the second time instant,
Figure FDA0002303721410000056
is the molar mass of methane molecules.
8. A natural gas substitution parameter acquisition system, comprising:
the first acquisition module is used for acquiring replacement experiment data of methane replaced by carbon dioxide;
the first methane concentration calculation module is used for acquiring an absorbance curve of methane at a first moment, integrating the absorbance curve of methane at the first moment on a frequency domain to obtain a first integral area, and calculating the methane concentration at the first moment according to the first integral area and the replacement experiment data;
the second methane concentration calculating module is used for acquiring an absorbance curve of the methane at a second moment, integrating the absorbance curve of the methane at the second moment in a frequency domain to obtain a second integral area, and calculating the methane concentration at the second moment according to the second integral area and the replacement experiment data;
a first displacement calculation module, configured to calculate a displacement of methane in a first time period according to the methane concentration at the first time, the methane concentration at the second time, and the displacement experiment data, where the first time period is a time period between the first time and the second time;
and the replacement rate calculation module is used for calculating the replacement rate of the methane in the first time period according to the replacement amount of the methane in the first time period.
9. A terminal device comprising a memory, a processor and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the natural gas substitution parameter acquisition method according to any one of claims 1 to 7 when executing the computer program.
10. A computer-readable storage medium, storing a computer program which, when executed by one or more processors, performs the steps of the natural gas substitution parameter acquisition method of any one of claims 1 to 7.
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