A gas logging method and device containing carbon isotope methane

Abstract

The present invention discloses a gas logging method and device containing carbon isotope methane, and proposes a novel oil and gas exploration wellhead gas detection method and system that combines a Fourier transform infrared spectroscopy absorption multi-component gas detection and analysis method with a tunable laser carbon isotope methane gas detection and analysis method. The method can accurately detect multi-component alkane gas and ultra-low concentration carbon isotope methane, solving the problem of being unable to simultaneously detect multi-component characteristic gas and ultra-low concentration carbon isotope methane gas in wellhead gas, and greatly improving the wellhead gas detection logging method. The present invention has the rapid responsiveness of in-situ detection and analysis, and eliminates the interference of environmental changes on detection performance through baseline correction processing technology and constant temperature control technology, so the requirements for the detection environment are not high, laying a foundation for the accuracy and stability of measurement and analysis results in various environments.

Description

Technical Field

[0001] The invention belongs to the technical field of online quantitative analysis of instruments and meters, gas logging and geological survey, and relates to a gas logging method and device containing carbon isotope methane. Background Art

[0002] Gas logging technology for oil and gas exploration is developing rapidly. Conventional gas logging methods include gas chromatography / catalytic combustion / mass spectrometry detection, tunable laser carbon isotope detection, and Fourier transform infrared spectroscopy absorption gas detection. In recent years, researchers have also proposed a Raman spectroscopy-based carbon isotope gas detection method, but it has not yet been applied to the field of gas logging for oil and gas exploration. As the difficulty of oil and gas extraction increases, higher requirements will be placed on gas logging methods.

[0003] The gas chromatography / catalytic combustion / mass spectrometry detection method generally uses the sampling and bringing back method for detection, and the whole set of equipment is not convenient to transport, so there is a lag in the detection time, and it is difficult to achieve in-situ online monitoring. Although researchers have optimized and improved this method in recent years, it can achieve online monitoring in some research fields, but it has not achieved online monitoring in the field of oil and natural gas logging. In addition, when using this method for gas detection, the chromatographic column is easily contaminated, which will cause errors in the detection.

[0004] Tunable laser carbon isotope logging technology has been applied in many oil fields in my country since 2014, and can meet the requirements of online monitoring. However, the tunable laser carbon isotope gas detection technology currently used in the field of oil and gas exploration uses a light source with a central wavelength in the near-infrared band, and is interfered by alkane gas, with a detection limit of 10×10 -6 The above, and the absorbance of carbon isotope gas in the near-infrared band is lower than that in the mid-infrared band. Therefore, the detection limit of the tunable laser carbon isotope methane gas mid-infrared detection technology can be further extended downward on the basis of the near-infrared detection technology, thereby improving the detection capability of ultra-low concentration carbon isotope methane. Due to its narrow-band measurement characteristics, the tunable laser gas detection technology has limited detection gas types and can only detect carbon isotope methane gas. In the process of oil and natural gas exploration, there are many types of characteristic gases, and some detection environments cannot judge oil and gas reserves, changes and other information based solely on the content of carbon isotope methane gas. In addition, the absorption spectra of alkane gases in the characteristic gases overlap severely, which will affect the detection results of tunable laser carbon isotope methane gas and introduce errors to the detection.

[0005] Fourier transform infrared spectroscopy absorption multi-component gas detection technology has unique advantages in analyzing characteristic gases in wellhead gas of oil and natural gas exploration wells. Its rapid response can meet the requirements of in-situ online monitoring, and it can accurately analyze the gas components and concentrations from characteristic alkane gases with serious spectral overlap. Its advantages such as easy operation and small instrument size make it have good application prospects in the field of oil and gas exploration. The only drawback is that it is difficult to detect concentrations less than 1×10 -6 characteristic gas.

[0006] In view of the above problems, the present invention combines Fourier transform infrared spectroscopy absorption gas detection technology with tunable laser isotope gas detection technology to form a mid-infrared gas logging system and method that can realize carbon isotope methane logging. The advantages of Fourier transform infrared spectroscopy analysis in multi-component gas detection are combined with the advantages of tunable laser detection method in detecting ultra-low concentration gas detection in the mid-infrared band. While ensuring accurate detection of multi-component gases, it can also accurately detect ultra-low concentrations. 13 CH4, 12 CH4 gas, which can improve the efficiency of wellhead gas detection and is of great significance to the improvement of energy exploration and real-time isotope logging technology. Summary of the invention

[0007] The purpose of the present invention is to solve the problems in the prior art and provide a gas logging method and device containing carbon isotope methane. The present invention has rapid responsiveness of in-situ detection and analysis, and eliminates the interference of environmental changes on detection performance through baseline correction processing technology and constant temperature control technology, so the requirements for the detection environment are not high, laying a foundation for the accuracy and stability of measurement and analysis results in various environments.

[0008] In order to achieve the above object, the present invention adopts the following technical solutions:

[0009] In a first aspect, the present invention provides a gas logging method containing carbon isotope methane, comprising the following steps:

[0010] Acquire the infrared light of the gas to be tested and pre-process the infrared spectrum;

[0011] According to the pre-processed infrared spectrum data, the concentration values ​​of carbon isotope methane and other gases in the gas to be tested are calculated using the Fourier transform infrared spectrum detection and analysis model;

[0012] Obtain the absorbance value of carbon isotope methane in the gas to be tested at a characteristic wavelength;

[0013] According to the absorbance value, the concentration value of carbon isotope methane is calculated using the tunable laser carbon isotope methane detection and analysis model;

[0014] The carbon isotope methane concentration values ​​calculated by the Fourier transform infrared spectroscopy detection and analysis model and the tunable laser carbon isotope methane detection and analysis model are compared. If the concentration value is greater than or equal to 100×10 -6 , output the concentration values ​​of carbon isotope methane and other gases calculated by the Fourier transform infrared spectroscopy detection and analysis model, otherwise output the concentration values ​​of other gases calculated by the Fourier transform infrared spectroscopy detection and analysis model and the concentration value of carbon isotope methane calculated by the tunable laser carbon isotope methane detection and analysis model;

[0015] Combined with the real-time detection data of the temperature and pressure detection module, the output carbon isotope methane concentration value and the concentration value of other gases are compensated for temperature and pressure;

[0016] The concentration values ​​of carbon isotope methane and other gases after temperature and pressure compensation are stored and remotely transmitted as the original data of logging.

[0017] Furthermore, the preprocessing of the present invention includes smoothing noise reduction processing, baseline drift correction processing and Fourier deconvolution processing; the gas to be measured is 13 CH4, 12 CH4, C2H6, C3H8, iso-C4H 10 、n-C4H 10 、iso-C5H 12 、n-C5H 12 A mixture of , CO, and CO2.

[0018] Furthermore, the Fourier transform infrared spectroscopy detection and analysis model of the present invention uses infrared spectroscopy data of different concentrations of the gas to be tested as input before being put into use, and uses the support vector machine algorithm to establish a quantitative analysis model of a single gas. The specific construction method is as follows:

[0019] 1) Sample production

[0020] Perform spectral scanning on the fixed component gas sample to obtain spectral data; perform n groups of calibration to obtain n groups of calibration sample pairs {Φ i ,X i}, representing the input-output relationship; where Φ i is the input sample set, which is an l-dimensional vector, where l is the number of gas components to be detected; X i is the output sample set, which is an m-dimensional vector, where m is the number of samples;

[0021]

[0022] X i =[x i1 ,x i2 ,…,x im ]

[0023] Where i = 1, 2, ..., n, n represents the number of samples; is the calibration value of the concentration of the l-type measured gas input into the spectrometer during the i-th calibration; x i1 ,x i2 ,…,x im is the spectral data output by the infrared spectrum detection system during the i-th calibration:

[0024] x im =I a (γ m ) / I ao (γ m ) (1)

[0025] Among them, I ao (γ m ) is the wave number γ m The intensity of infrared light incident into the air chamber; I a (γ m ) is the wave number transmitted out of the air chamber, which is γ m Infrared light intensity;

[0026] 2) Establish Fourier transform infrared spectroscopy detection and analysis model

[0027] 2-1) Training:

[0028] Randomly select 3 / 5 of the total number of calibration sample sets as training samples; input the training sample set into the support vector machine in parallel and serial modes, which are called parallel support vector and serial support vector respectively;

[0029] The serial vector X of each serial input sample is [x1, x2, ..., x m ] with each parallel input row kernel vector X i =[x i1 ,x i2 ,…,x im ], perform the function operation K(X,X i ), then the output Y of the support vector machine is as follows:

[0030]

[0031] Among them, b is the intercept of the curve on the y-axis, a i is the coefficient vector, K(X,X i ) is the RBF kernel function, and e is a natural constant, σ is the RBF kernel parameter;

[0032] Each serial input of a serial vector obtains an output according to formula (2); after n serial inputs, n outputs Y are obtained. (1,2,…,n), and compare it to the expected methane concentration Compare them. If the comparison between the two does not meet the set mean square error ε<10 -6 , then the parameter a needs to be i , b and kernel function parameter σ are adjusted until ε<10 -6 By the time , the support vector machine training is completed.

[0033] Furthermore, after the support vector machine of the present invention is trained, it is tested, and the specific method is as follows:

[0034] Take another 2 / 5 of the total number of calibration samples as test samples; input the test sample set vectors serially into the trained support vector machine as serial support vectors; the support vector machine outputs the output value Y' in sequence (1,2,…,n) , the output value of the support vector machine is Y' (1,2,…,n) and the expected methane concentration If the difference meets the accuracy requirement, it indicates that the model can be used for actual concentration inversion.

[0035] Furthermore, the tunable laser carbon isotope methane detection and analysis model of the present invention is a quantitative analysis model established by taking the absorbance data of carbon isotope methane gas of different concentrations at characteristic wavelengths as input before being put into use. The specific construction method is as follows:

[0036] (1) Calibration

[0037] 1-1) Modulate the laser light source to output a laser signal with a central wavelength of λ1; the laser signal is incident on a known concentration of N i of 13 CH4 gas, record the peak value of the second harmonic of the emitted absorption signal I bi , the carbon concentrations of each known 13 The slope value K0 is obtained by linear fitting of CH4 concentration and the second harmonic peak of the absorption signal:

[0038]

[0039] Where i = 1, 2, ..., m;

[0040] 1-2) Modulate the laser light source to make it output a laser signal with a central wavelength of λ2; the laser signal is incident on a known concentration of N i of 13 CH4 gas, record the peak value I' of the second harmonic of the emitted absorption signal bi , the carbon concentrations of each known 13 The slope value K1 is obtained by linear fitting of CH4 concentration and the second harmonic peak of the absorption signal:

[0041]

[0042] 1-3) Modulate the laser light source so that it outputs a laser signal with a central wavelength of λ1; the laser signal is incident on a known concentration of N j of 12 CH4 gas, record the peak value of the second harmonic of the emitted absorption signal I bj , the carbon concentrations of each known 12 The slope value K2 is obtained by linear fitting of CH4 concentration and the second harmonic peak of the absorption signal:

[0043]

[0044] Where, j = 1, 2, ..., m;

[0045] 1-4) Modulate the laser light source so that the laser light source outputs a laser signal with a central wavelength of λ2; the laser signal is incident on a known concentration of N j of 13 CH4 gas, record the peak value I' of the second harmonic of the emitted absorption signal bj , the carbon concentrations of each known 13 The slope value K3 is obtained by linear fitting of CH4 concentration and the second harmonic peak of the absorption signal:

[0046]

[0047] (2) Establishing an analysis model

[0048] Modulate the laser light source so that it outputs laser signals with central wavelengths of λ1 and λ2, and record the absorption signal second harmonic peak values ​​I at the output wavelengths of λ1 and λ2 of the laser light source. λ1 and I λ2 ,but 13 CH4, 12 The relationship between CH4 concentration and slope value:

[0049] I λ1 =K1N x +K2N y (7)

[0050] I λ2 =K1N x +K3N y (8)

[0051] Among them, N x express 13 The concentration of CH4; N y express 12 CH4 concentration.

[0052] In a second aspect, the present invention provides a gas logging device containing carbon isotope methane, comprising:

[0053] A wellhead gas connection module, which is used to transport the gas at the wellhead to the Fourier transform infrared spectroscopy absorption multi-component gas detection system;

[0054] A Fourier transform infrared spectroscopy absorption multi-component gas detection system is used to obtain infrared absorption spectrum data of wellhead gas; the Fourier transform infrared spectroscopy absorption multi-component gas detection system is connected to a tunable laser carbon isotope methane gas detection system;

[0055] Tunable laser carbon isotope methane gas detection system, used to obtain the absorbance data of carbon isotope methane in wellhead gas at the central wavelength;

[0056] A temperature and pressure detector, which is installed on the tunable laser carbon isotope methane gas detection system and is used to monitor the temperature and pressure inside the tunable laser carbon isotope methane gas detection system in real time;

[0057] The data processing and control module is connected to the Fourier transform infrared spectroscopy absorption multi-component gas detection system, the tunable laser carbon isotope methane gas detection system, the temperature and pressure detector and the telemetry information module, and is used to calculate the components and concentration values ​​of the gas to be tested based on the infrared absorption spectrum data, absorbance data, temperature and air pressure data, and transmit them to the main control room through the telemetry information module.

[0058] Furthermore, the wellhead gas connection module of the present invention includes a connecting pipe and a valve. The wellhead gas enters the Fourier transform infrared spectroscopy absorption multi-component gas detection system through the connecting pipe, and its on-off is controlled by the valve.

[0059] Furthermore, the Fourier transform infrared spectroscopy absorption multi-component gas detection system of the present invention includes an infrared light source and an interferometer, a double-cone gas cell and an infrared detector, wherein the infrared light source, the interferometer and the infrared detector are arranged at both ends of the double-cone gas cell; the double-cone gas cell is provided with an air inlet, which is connected to a connecting pipe; the outlet of the double-cone gas cell is connected to a tunable laser carbon isotope methane gas detection system; the infrared light source, the interferometer and the infrared detector all interact with a data processing and control module.

[0060] Furthermore, in the tunable laser carbon isotope methane gas detection system of the present invention, an infrared laser light source, a long optical path gas cell and a laser detector, a mid-infrared laser light source and a laser detector are arranged at both ends of the long optical path gas cell; the long optical path gas cell is provided with an outlet, and the detected gas flows out through the outlet; the inlet of the long optical path gas cell is connected to the Fourier transform infrared spectroscopy absorption multi-component gas detection system; the mid-infrared laser light source and the laser detector both interact with the data processing and control module.

[0061] Furthermore, the data processing and control module of the present invention is provided with a display screen for displaying the components of the gas to be measured and their concentration values.

[0062] Compared with the prior art, the present invention has the following beneficial effects:

[0063] In the field of well gas logging based on infrared spectroscopy analysis, the present invention proposes a new oil and gas exploration well wellhead gas detection method and system that combines the Fourier transform infrared spectroscopy absorption multi-component gas detection and analysis method with the tunable laser carbon isotope methane gas detection and analysis method. The method can accurately detect multi-component alkane gas and ultra-low concentration carbon isotope methane at the same time, solving the problem of being unable to simultaneously detect multi-component characteristic gas and ultra-low concentration carbon isotope methane gas in the wellhead gas, and greatly improving the wellhead gas detection and logging method. BRIEF DESCRIPTION OF THE DRAWINGS

[0064] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0065] Figure 1 It is a schematic diagram of the spectrum analysis of the present invention.

[0066] Figure 2 It is a structural diagram of the detection system of the present invention.

[0067] Figure 3 For the present invention 13 CH4, 12 CH4 gas absorbance spectrum.

[0068] Figure 4 For the present invention 13 CH4, 12 Absorbance spectrum of CH4 gas near 3.3 microns.

[0069] Figure 5 It is a schematic diagram of the support vector algorithm structure of the present invention.

[0070] in: DETAILED DESCRIPTION

[0071] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0072] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0073] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0074] In the description of the embodiments of the present invention, it should be noted that if the terms "upper", "lower", "horizontal", "inner", etc. indicate an orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product of the invention is usually placed when in use, it is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "first", "second", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0075] In addition, if the term "horizontal" appears, it does not mean that the component must be absolutely horizontal, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", which does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0076] In the description of the embodiments of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal connection of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0077] The present invention is further described in detail below in conjunction with the accompanying drawings:

[0078] See also Figure 1 The embodiment of the present invention discloses a gas logging method containing carbon isotope methane, comprising the following steps:

[0079] S1 obtains the infrared light of the gas to be tested and preprocesses the infrared spectrum; the preprocessing includes smoothing and noise reduction processing, baseline drift correction processing and Fourier deconvolution processing; the gas to be tested is 13 CH4, 12 CH4, C2H6, C3H8, iso-C4H 10 、n-C4H 10 、iso-C5H 12 、n-C5H 12 A mixture of , CO, and CO2.

[0080] S2 calculates the concentration values ​​of carbon isotope methane and other gases in the gas to be tested based on the pre-processed infrared spectrum data using the Fourier transform infrared spectrum detection and analysis model; the Fourier transform infrared spectrum detection and analysis model is a quantitative analysis model of a single gas established by using the infrared spectrum data of the gas to be tested of different concentrations as input before being put into use using the support vector machine algorithm. The specific construction method is as follows:

[0081] 1) Sample production

[0082] Perform spectral scanning on the fixed component gas sample to obtain spectral data; perform n groups of calibration to obtain n groups of calibration sample pairs {Φ i ,X i}, representing the input-output relationship; where Φ i is the input sample set, which is an l-dimensional vector, where l is the number of gas components to be detected; X i is the output sample set, which is an m-dimensional vector, where m is the number of samples;

[0083]

[0084] X i =[x i1 ,x i2 ,…,x im ]

[0085] Where i = 1, 2, ..., n, n represents the number of samples; is the calibration value of the concentration of the l-type measured gas input into the spectrometer during the i-th calibration; x i1 ,x i2 ,…,x imis the spectral data output by the infrared spectrum detection system during the i-th calibration:

[0086] x im =I a (γ m ) / I ao (γ m ) (1)

[0087] Among them, I ao (γ m ) is the wave number γ m The intensity of infrared light incident into the air chamber; I a (γ m ) is the wave number transmitted out of the air chamber, which is γ m Infrared light intensity;

[0088] 2) Establish Fourier transform infrared spectroscopy detection and analysis model

[0089] 2-1) Training:

[0090] Randomly select 3 / 5 of the total number of calibration sample sets as training samples; input the training sample set into the support vector machine in parallel and serial modes, which are called parallel support vector and serial support vector respectively;

[0091] The serial vector X of each serial input sample is [x1, x2, ..., x m ] with each parallel input row kernel vector X i =[x i1 ,x i2 ,…,x im ], perform function operation K(X,X i ), then the output Y of the support vector machine is as follows:

[0092]

[0093] Among them, b is the intercept of the curve on the y-axis (i.e., fitting error), a i is the coefficient vector, K(X,X i ) is the RBF kernel function, and e is a natural constant, σ is the RBF kernel parameter;

[0094] Each serial input of a serial vector obtains an output according to formula (2); after n serial inputs, n outputs Y are obtained. (1,2,…,n) , and compare it to the expected methane concentration Compare them. If the comparison between the two does not meet the set mean square error ε<10 -6 , then the parameter a needs to be i , b and kernel function parameter σ are adjusted until ε<10 -6By the time , the support vector machine training is completed.

[0095] After the support vector machine is trained, it is tested. The specific method is as follows:

[0096] Take another 2 / 5 of the total number of calibration samples as test samples; input the test sample set vectors serially into the trained support vector machine as serial support vectors; the support vector machine outputs the output value Y' in sequence (1,2,…,n) , the output value of the support vector machine is Y' (1,2,…,n) and the expected methane concentration If the difference meets the accuracy requirement, it indicates that the model can be used for actual concentration inversion.

[0097] S3 obtains the absorbance value of carbon isotope methane in the gas to be tested at a characteristic wavelength;

[0098] S4 calculates the concentration value of carbon isotope methane according to the absorbance value using a tunable laser carbon isotope methane detection and analysis model; the tunable laser carbon isotope methane detection and analysis model is a quantitative analysis model established by taking the absorbance data of carbon isotope methane gas of different concentrations at a characteristic wavelength as input before being put into use, and the specific construction method is as follows:

[0099] (1) Calibration

[0100] The central wavelength of the light source in the laser detection system is λ1, and the output intensity is I bo The laser signal of the long optical path gas cell is L. Under this condition, the concentration of each known i (i=1,2,…,m) 13 CH4 is introduced into the long optical path gas cell, and the peak value I of the second harmonic of the absorption signal emitted from the gas cell is recorded. bi (i=1,2,…,m), the carbon 13 The slope value of the linear fit between CH4 concentration and the second harmonic peak of the absorption signal is N0 / I b0 ,but 13 The relationship between CH4 concentration and the second harmonic peak of the absorption signal can be expressed as:

[0101]

[0102] The laser light source is modulated to output a wavelength of λ2. Calibration is performed under the same conditions. The peak value I' of the second harmonic of the absorption signal emitted from the gas cell is recorded. bi (i=1,2,…,m), we get 13 The linear fitting slope value of CH4 calibration is N1 / I b1 ,but 13The relationship between CH4 concentration and the second harmonic peak of the absorption signal can be expressed as:

[0103]

[0104] Similarly, at wavelengths λ1 and λ2, 12 CH4 is used for calibration and the concentration is recorded as N j (j=1,2,…,m) 12 The second harmonic peak I of the absorption signal of CH4 at λ1 and λ2 bj and I' bj , then the relationship between the concentration and the second harmonic peak of the absorption signal is:

[0105]

[0106]

[0107] (2) Establishing an analysis model

[0108] The gas to be tested containing unknown carbon isotope methane is passed into the long optical path gas cell, and the second harmonic peak value I of the absorption signal at the light source output wavelengths λ1 and λ2 is obtained and recorded. λ1 and I λ2 Then we can use equations (7) and (8) to solve 13 CH4, 12 CH4 concentration.

[0109]

[0110]

[0111] Where N x express 13 The concentration of CH4, Figure 1 The y in 12 ; N y express 12 The concentration of CH4, Figure 1 The y in 22 .

[0112] S5 compares the carbon isotope methane concentration values ​​calculated by the Fourier transform infrared spectroscopy detection and analysis model and the tunable laser carbon isotope methane detection and analysis model. If the concentration value is greater than or equal to 100×10 -6 , output the concentration values ​​of carbon isotope methane and other gases calculated by the Fourier transform infrared spectroscopy detection and analysis model, otherwise output the concentration values ​​of other gases calculated by the Fourier transform infrared spectroscopy detection and analysis model and the concentration value of carbon isotope methane calculated by the tunable laser carbon isotope methane detection and analysis model;

[0113] S6 combines the real-time detection data of the temperature and pressure detection module to perform temperature and pressure compensation on the output carbon isotope methane concentration value and other gas concentration values;

[0114] S7 stores and remotely transmits the concentration values ​​of carbon isotope methane and other gases after temperature and pressure compensation as the raw data for logging.

[0115] like Figure 2 As shown, an embodiment of the present invention discloses a gas logging device containing carbon isotope methane, comprising:

[0116] A wellhead gas connection module is used to transport the gas at the wellhead to the Fourier transform infrared spectroscopy absorption multi-component gas detection system; the wellhead gas connection module includes a connecting pipe 1 and a valve 2, and the wellhead gas enters the Fourier transform infrared spectroscopy absorption multi-component gas detection system through the connecting pipe 1, and its on and off is controlled by the valve 2.

[0117] A Fourier transform infrared spectroscopy absorption multi-component gas detection system is used to obtain infrared absorption spectral data of wellhead gas; the Fourier transform infrared spectroscopy absorption multi-component gas detection system is connected with a tunable laser carbon isotope methane gas detection system; the Fourier transform infrared spectroscopy absorption multi-component gas detection system includes an infrared light source and interferometer 4, a bi-conical gas pool 5 and an infrared detector 6, the infrared light source and interferometer 4 and the infrared detector 6 are arranged at both ends of the bi-conical gas pool 5; the bi-conical gas pool 5 is provided with an air inlet 3, and the air inlet 3 is connected with a connecting pipe 1; the outlet of the bi-conical gas pool 5 is connected with the tunable laser carbon isotope methane gas detection system; the infrared light source and interferometer 4 and the infrared detector 6 all interact with a data processing and control module 12.

[0118] A tunable laser carbon isotope methane gas detection system is used to obtain the absorbance data of carbon isotope methane in wellhead gas at the central wavelength; the tunable laser carbon isotope methane gas detection system comprises an infrared laser light source 7, a long optical path gas cell 8 and a laser detector 13, wherein the mid-infrared laser light source 7 and the laser detector 13 are arranged at both ends of the long optical path gas cell 8; the long optical path gas cell 8 is provided with an outlet 10, and the detected gas flows out through the outlet 10; the inlet of the long optical path gas cell 8 is connected to the Fourier transform infrared spectroscopy absorption multi-component gas detection system; the mid-infrared laser light source 7 and the laser detector 13 both interact with the data processing and control module 12.

[0119] A temperature and pressure detector 11, wherein the temperature and pressure detector 11 is installed on the tunable laser carbon isotope methane gas detection system and is used to monitor the temperature and pressure inside the tunable laser carbon isotope methane gas detection system in real time;

[0120] The data processing and control module 12 is connected to the Fourier transform infrared spectroscopy absorption multi-component gas detection system, the tunable laser carbon isotope methane gas detection system, the temperature and pressure detector 11 and the telemetry information module 14, and is used to calculate the components and concentration values ​​of the gas to be measured according to the infrared absorption spectrum data, absorbance data, temperature and pressure data, and transmit them to the main control room through the telemetry information module 14. The data processing and control module 12 is provided with a display screen 9 for displaying the components and concentration values ​​of the gas to be measured.

[0121] Example 1

[0122] The analysis process of the carbon isotope methane mid-infrared gas logging method proposed in the present invention is as follows: Figure 1 shown.

[0123] The following steps are involved:

[0124] Step 1: Use the Fourier transform infrared spectroscopy absorption multi-component gas detection system to obtain the infrared spectrum of the gas to be tested.

[0125] Step 2: Preprocess the infrared spectrum of the mixed gas by smoothing and noise reduction, baseline drift correction, and Fourier deconvolution.

[0126] Step 3: Before putting it into use, use different concentrations of 13 CH4, 12 CH4, C2H6, C3H8, iso-C4H 10 、n-C4H 10 、iso-C5H 12 、n-C5H 12 The infrared spectrum data of CO, CO2 and other gases are used to establish the Fourier transform infrared spectrum detection and analysis model of single gas respectively by using the support vector machine algorithm; after being put into use, the infrared spectrum data of the gas to be tested after pretreatment is directly used, and the concentration value y of the corresponding gas is calculated in combination with the quantitative analysis model. 11 ,y 21 ,y3,y4,y5,y6,y7,y8,y9,y 10 .

[0127] The modeling steps of the Fourier transform infrared spectroscopy detection and analysis model are as follows:

[0128] (1) Sample preparation

[0129] Input fixed composition gas sample X into the double cone gas cell i , and perform spectral scanning to obtain spectral data Φ i , conduct n groups of calibration experiments and obtain n groups of calibration sample pairs {Φ i ,X i}, representing the input-output relationship, where Φ i is an l-dimensional vector, where l is the number of gas components to be detected. is the calibration value of the concentration of the l-type measured gas input into the spectrometer during the i-th calibration; X i is an m-dimensional vector, m is the number of samples, x i1 ,x i2 ,…,x ij ,…,x im is the spectral data output by the infrared spectrum detection system during the i-th calibration, that is:

[0130] Input sample set

[0131] Output sample set X i =[x i1 ,x i2 ,…x ij ,…,x im ],i=1,2,…,n

[0132] Where n represents the number of samples. When n is large enough and the sample set is complete, the set constitutes a positive model of the infrared spectrum detection system.

[0133] When the total number of calibration times n = 500, there are 500 sets of {Φ i ,X i The sample pair set constitutes the calibration sample set, which characterizes the positive model of the spectrometer. i The element x ij As a ratio

[0134] x ij =I a (γ j ) / I ao (γ j ) (1)

[0135] Where: I ao (γ j ) is the wave number γ j The intensity of infrared light incident into the air chamber; I a (γ j ) is the wave number transmitted out of the air chamber, which is γ j Infrared light intensity;

[0136] Spectral data x output by Fourier infrared spectroscopy detection system ij Indicates the wave number γ of a certain type of gas at a certain concentration jThe degree of infrared light absorption or transmission reflects the type of gas and its concentration. Therefore, the positive model of the infrared spectrum detection system reflects that the system is a multi-sensor array that can be sensitive to multiple gas types and values, and can be used to establish a multi-sensor system for monitoring multi-component gases.

[0137] (2) Establishing Fourier transform infrared spectroscopy detection and analysis model

[0138] The Fourier transform infrared spectroscopy detection and analysis model is a model that takes certain spectral line data as input and the target gas concentration as output, and is also called the inverse model of the infrared spectroscopy detection system. The present invention uses the support vector machine algorithm as an example to establish the inverse model. The inverse model outputs y 11 ,y 21 ,y3,y4,y5,y6,y7,y8,y9,y 10 Indicates the concentrations of 10 gases to be tested. They should be as close as possible to the actual concentration values ​​of each component of the gas to be tested input by the system The closeness between the two should meet the accuracy requirements. The support vector structure diagram is as follows Figure 5 As shown, α i , b is the support vector machine structure parameter, α i (i=1,2,…,n) is the weight coefficient, b is the threshold or offset, which is determined by "training" and "testing" the support vector machine.

[0139] Training: Outputting methane concentration using a support vector machine For example

[0140] Randomly select 3 / 5 of the total number of calibration sample sets as training samples, that is, n = 300. Set the 300 sets of training sample set vectors X i =X ij =[x i1 ,x i2 ,…,x ij ,…,x im ], i = 1, 2, ..., n, j = 1, 2, ..., m are input into the support vector machine in parallel and serial ways, and are respectively called parallel support vector and serial support vector.

[0141] The serial vector X of each serial input sample is j}=[x1,x2,…,x j ,…,x m ] with each parallel input row kernel vector X i ={X ij}=[x i1 ,x i2 ,…,x ij ,…,x im ], perform the function operation K(X,X i), if the RBF kernel is selected, the output Y of the support vector machine is determined by the following formula

[0142]

[0143] Where RBF kernel function σ is the RBF kernel parameter.

[0144] Each serial input of a serial vector will produce an output according to formula (2). After n serial inputs, that is, after all n training samples are input, n outputs Y can be obtained. (1,2,…,n) , and the desired output is the actual methane concentration If the comparison between the two does not meet the set mean square error ε < 10 -6 , we need to adjust the parameter α i , b and kernel function parameter σ are adjusted until ε<10 -6 By the time , the support vector machine training is completed.

[0145] b. Test: Take another 2 / 5 of the total number of calibration samples as test samples, that is, n = 200. All 200 sets of test sample set vectors are serially input into the trained support vector machine as serial support vectors. The support vector machine outputs n = 200 output values ​​Y' in sequence (1,2,…,n) , and the corresponding expected output, i.e. the actual methane concentration If the difference meets the accuracy requirement, it indicates that the model can be used for actual concentration inversion.

[0146] Similarly, the support vector machine is trained and tested for other gas components in the same way as above, so as to establish a support vector machine with its own structural parameter α i , b and kernel function parameter σ are used to measure and analyze the concentration of each component in the mixed gas.

[0147] Step 4: Use the tunable laser carbon isotope methane gas detection system to obtain the 13 CH4, 12 The absorbance value at the characteristic wavelength of CH4.

[0148] Step 5: Use different concentrations of 13 CH4, 12 The absorbance data at the characteristic wavelength of CH4 gas was used to establish a tunable laser carbon isotope methane detection and analysis model; after it was put into use, 13 CH4, 12 The absorbance value at the characteristic wavelength of CH4 is combined with the quantitative analysis model to calculate its concentration value y 12 ,y 22 .

[0149] The modeling steps of the tunable laser carbon isotope methane detection and analysis model are as follows:

[0150] 2) The purpose of the adjustable laser detection system is to detect ultra-low concentrations of carbon isotope methane. The process is to modulate the intensity of I bo The laser is irradiated to the light inlet of the long optical path gas pool through the collimating lens, and then irradiated to the detector light hole from the light outlet after multiple reflections in the long optical path gas pool. The second harmonic light intensity I b .like Figure 3 Figure 4 As shown, 12 The transmittance of CH4 has a very high peak value near the wavelength of 3317nm. 13 CH4 has a very high peak transmittance around 3325nm, so these two wavelengths are detected simultaneously. 13 CH4, 12 CH4 is in a good position, the steps for analyzing the system are as follows:

[0151] (1) Calibration

[0152] The central wavelength of the light source in the laser detection system is λ1, and the output intensity is I bo The laser signal of the long optical path gas cell is L. Under this condition, the concentration of each known i (i=1,2,…,m) 13 CH4 is introduced into the long optical path gas cell, and the peak value I of the second harmonic of the absorption signal emitted from the gas cell is recorded. bi (i=1,2,…,m), each carbon with known concentration 13 The slope value of the linear fit between CH4 concentration and the second harmonic peak of the absorption signal is N0 / I b0 ,but 13 The relationship between CH4 concentration and the second harmonic peak of the absorption signal can be expressed as:

[0153]

[0154] The laser light source is modulated to output a wavelength of λ2. Calibration is performed under the same conditions. The peak value I' of the second harmonic of the absorption signal emitted from the gas cell is recorded. bi (i=1,2,…,m), we get 13 The linear fitting slope value of CH4 calibration is N1 / I b1 ,but 13 The relationship between CH4 concentration and the second harmonic peak of the absorption signal can be expressed as:

[0155]

[0156] Similarly, at wavelengths λ1 and λ2, 12 CH4 is used for calibration and the concentration is recorded as N j (j=1,2,…,m) 12 The second harmonic peak I of the absorption signal of CH4 at λ1 and λ2 bj and I' bj , then the relationship between the concentration and the second harmonic peak of the absorption signal is:

[0157]

[0158]

[0159] (2) Establishing an analysis model

[0160] The gas to be tested containing unknown carbon isotope methane is passed into the long optical path gas cell, and the second harmonic peak value I of the absorption signal at the light source output wavelengths λ1 and λ2 is obtained and recorded. λ1 and I λ2 Then we can use equations (7) and (8) to solve 13 CH4, 12 CH4 concentration.

[0161]

[0162]

[0163] Where N x express 13 The concentration of CH4, Figure 1 The y in 12 ; N y express 12 The concentration of CH4, Figure 1 The y in 22 .

[0164] Step 6: Data processing module analysis 13 CH4, 12 If the CH4 concentration is greater than or equal to 100×10 -6 Time y 11 ,y 21 If it is less than 100×10 -6 Time y 12 ,y 22 shall prevail and be the final 13 CH4, 12 The CH4 concentration values ​​are output as y1 and y2.

[0165] Step 7, combining the real-time detection data of the temperature and pressure detection module to perform temperature and pressure compensation on the output of the quantitative analysis model;

[0166] Step 8: Finally, the gas concentration analysis results after temperature and pressure compensation are stored and remotely transmitted as raw data for logging.

[0167] Example 2

[0168] The system structure of carbon isotope methane mid-infrared gas logging proposed by the present invention is as follows: Figure 2 As shown in the figure, the system includes six modules: a wellhead gas connection module, a Fourier transform infrared spectroscopy absorption multi-component gas detection system, a tunable laser carbon isotope methane gas detection system, a temperature and pressure detection module, a data processing and control module, and a remote information module. The latter five parts can be collectively referred to as a detection system. Among them, the wellhead gas connection module is composed of a connecting pipe 1 and a valve 2. After the wellhead gas opens the valve 2, it enters the detection system from the air inlet 3 and flows out from the air outlet 10. The Fourier transform infrared spectroscopy absorption multi-component gas detection system is composed of an infrared light source and an interferometer 4, a double-cone gas cell 5 and an infrared detector 6, which are used to obtain infrared absorption spectrum data of the wellhead gas. The tunable laser carbon isotope methane gas detection system is composed of a mid-infrared laser light source 7, a long optical path gas cell 8 and a laser detector 13, which are used to obtain ultra-low concentration δ 13 C1, δ 12 The absorbance data of C1 gas near the central wavelength, a temperature and pressure detector 11 is installed on the long optical path gas pool to monitor the temperature and air pressure inside the detection system in real time; the data processing and control module 12 analyzes and processes the data detected by the Fourier transform infrared spectroscopy absorption multi-component gas detection system and the tunable laser carbon isotope methane gas detection system, and displays the gas components to be tested and their concentration values ​​on the display screen 9 in real time; the remote transmission information module 14 transmits the analysis and processing results to the main control room for storage for subsequent analysis and processing.

[0169] The Fourier transform infrared spectroscopy absorption multi-component gas detection system can simultaneously detect multi-component light alkane gases, carbon monoxide and carbon dioxide gases. After receiving the detection command from the data processing and control module, it starts to scan the absorption spectrum of the gas in the gas pool within the wavelength range of 2.5μm to 25μm, and transmits the obtained infrared absorption spectrum data to the data processing and control module. The data processing module pre-processes the spectrum data and obtains the following information after quantitative analysis: 13 CH4, 12 CH4, C2H6, C3H8, iso-C4H 10 、n-C4H 10 、iso-C5H 12 、n-C5H 12 Concentration values ​​y corresponding to multi-component light alkane gas and CO, CO2 gas 11 ,y 21 ,y3,y4,y5,y6,y7,y8,y9,y10 The tunable laser carbon isotope methane gas detection system mainly detects the concentration of 100×10 -6 The following δ 13 C1, δ 12 C1 gas, after receiving the detection command from the data processing and control module, starts to detect the delta 13 C1, δ 12 The detector converts the absorption light intensity signal of C1 gas near the center wavelength of the laser into an electrical signal and transmits it to the data processing and control module. 13 CH4, 12 The concentration value y of CH4 gas can be obtained by quantitative analysis of its absorption intensity data. 12 ,y 22 When the detection 13 CH4, 12 The CH4 carbon isotope methane concentration is less than 100×10 -6 Time y 12 ,y 22 Based on, when the test 13 CH4, 12 The CH4 carbon isotope methane concentration value is higher than 100×10 -6 Time y 11 ,y 21 The final concentration values ​​of the multi-component gas are y1, y2, y3, y4, y5, y6, y7, y8, y9, y 10 .

[0170] The scanning range of the Fourier transform infrared spectroscopy absorption multi-component gas detection system proposed in the present invention needs to include 3.07μm to 15.38μm, and the absorbance spectrum curve of the gas to be tested in the mid-infrared band is within the range of 3.07μm to 15.38μm. When the concentration of the characteristic gas is high, the absorbance near 3.3μm will be close to saturation, and the accuracy of analyzing its concentration value near 15μm will be higher.

[0171] The central wavelength of the light source of the tunable laser carbon isotope methane gas detection system proposed in the present invention is selected to be 3.32 μm, and the mid-infrared absorbance spectrum of carbon isotope methane gas is as shown in the figure: Figure 3 As shown, the absorbance near 3.3μm is the highest, and the absorbance curve near 3.3μm is as follows Figure 4 As shown, 13 CH4, 12 The absorbance curve of CH4 gas has a similar trend. 13 The peak of the absorbance curve of CH4 gas is at 3.325 μm. 12 The highest peak of the absorbance curve of CH4 gas is at 3.317μm, and the interval between the two is 7nm.13 The concentration of CH4 gas is generally 12 The CH4 gas concentration fluctuates by 1%, so for δ 13 The detection requirements for C1 gas are higher, so a laser light source with a central wavelength of 3.325μm is selected, and it can be distinguished within the wavelength modulation range. 13 CH4 gas and 12 CH4 gas.

[0172] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A gas logging method containing carbon isotope methane, characterized in that: The following steps are involved: Acquire the infrared light of the gas to be tested and pre-process the infrared spectrum; According to the pre-processed infrared spectrum data, the concentration values ​​of carbon isotope methane and other gases in the gas to be tested are calculated using the Fourier transform infrared spectrum detection and analysis model; Obtain the absorbance value of carbon isotope methane in the gas to be tested at a characteristic wavelength; According to the absorbance value, the concentration value of carbon isotope methane is calculated using the tunable laser carbon isotope methane detection and analysis model; Compare the carbon isotope methane concentration values ​​calculated by the Fourier transform infrared spectroscopy detection and analysis model and the tunable laser carbon isotope methane detection and analysis model. If the concentration value is greater than or equal to 100×10 -6 , output the concentration values ​​of carbon isotope methane and other gases calculated by the Fourier transform infrared spectroscopy detection and analysis model, otherwise output the concentration values ​​of other gases calculated by the Fourier transform infrared spectroscopy detection and analysis model and the concentration value of carbon isotope methane calculated by the tunable laser carbon isotope methane detection and analysis model; Combined with the real-time detection data of the temperature and pressure detection module, the output carbon isotope methane concentration value and the concentration value of other gases are compensated for temperature and pressure; The concentration values ​​of carbon isotope methane and other gases after temperature and pressure compensation are stored and remotely transmitted as the original data of logging.

2. The gas logging method containing carbon isotope methane according to claim 1, characterized in that: The preprocessing includes smoothing and noise reduction processing, baseline drift correction processing and Fourier deconvolution processing; the gas to be measured is 13 CH4, 12 CH4, C2H6, C3H8, iso-C4H 10 、n-C4H 10 、iso-C5H 12 、n-C5H 12 A mixture of , CO, and CO2.

3. The gas logging method containing carbon isotope methane according to claim 1 or 2, characterized in that: The Fourier transform infrared spectroscopy detection and analysis model is a quantitative analysis model of a single gas established by using the infrared spectroscopy data of the gas to be tested with different concentrations as input before being put into use, using the support vector machine algorithm. The specific construction method is as follows: 1) Sample preparation Perform spectral scanning on fixed component gas samples to obtain spectral data; Group calibration, get Group calibration sample pair set , represents the input-output relationship; among them, is the input sample set, which is a l dimensional vector, l is the number of gas components that need to be detected; is the output sample set, which is a m dimensional vector, m is the number of samples; in, , Indicates the number of samples; It is i During the second calibration, input the spectrometer l The calibration value of the measured gas concentration; It is i During the second calibration, the spectral data output by the infrared spectrum detection system is: in, Wave number The intensity of infrared light incident on the air chamber; The wave number transmitted out of the air chamber is Infrared light intensity; 2) Establishing Fourier transform infrared spectroscopy detection and analysis model 2-1) Training: Randomly select 3 / 5 of the total number of calibration sample sets as training samples; input the training sample set into the support vector machine in parallel and serial modes, which are called parallel support vector and serial support vector respectively; A serial vector of each serial input sample With each parallel input row kernel vector , perform function operations , then the output Y of the support vector machine is as follows: in, b is the intercept of the curve on the y-axis, a i is the coefficient vector, is the RBF kernel function, and , e is a natural constant, is the RBF kernel parameter; Each serial input of a serial vector obtains an output according to equation (2); Serial input, get Output , and compare it to the expected methane concentration Compare them. If the comparison between the two does not meet the set mean square error ε<10 -6 , the parameters need to be a i , b And kernel function parameters σ Adjust until ε<10 -6 By the time , the support vector machine training is completed.

4. The gas logging method containing carbon isotope methane according to claim 3, characterized in that: After the support vector machine is trained, it is tested. The specific method is as follows: Take another 2 / 5 of the total number of calibration samples as test samples; input the test sample set vectors serially into the trained support vector machine as serial support vectors; the support vector machine outputs the output values ​​in sequence , the output value of the support vector machine and the expected methane concentration If the difference meets the accuracy requirement, it indicates that the model can be used for actual concentration inversion.

5. The gas logging method containing carbon isotope methane according to claim 1, characterized in that: The tunable laser carbon isotope methane detection and analysis model is a quantitative analysis model established by taking the absorbance data of carbon isotope methane gas of different concentrations at characteristic wavelengths as input before being put into use. The specific construction method is as follows: (1) Calibration 1-1) Modulate the laser light source so that the output center wavelength of the laser light source is The laser signal is incident on a known concentration of of 13 CH4 gas, record the peak value of the second harmonic of the emitted absorption signal , the carbon concentrations of each known 13 The slope value is obtained by linear fitting of CH4 concentration and the second harmonic peak of the absorption signal : in, ; 1-2) Modulate the laser light source so that the output center wavelength of the laser light source is The laser signal is incident on a known concentration of of 13 CH4 gas, record the peak value of the second harmonic of the emitted absorption signal , the carbon concentrations of each known 13 The slope value is obtained by linear fitting of CH4 concentration and the second harmonic peak of the absorption signal : 1-3) Modulate the laser light source so that the output center wavelength of the laser light source is The laser signal is incident on a known concentration of of 12 CH4 gas, record the peak value of the second harmonic of the emitted absorption signal , the carbon concentrations of each known 12 The slope value is obtained by linear fitting of CH4 concentration and the second harmonic peak of the absorption signal : in, ; 1-4) Modulate the laser light source so that the output center wavelength of the laser light source is The laser signal is incident on a known concentration of of 13 CH4 gas, record the peak value of the second harmonic of the emitted absorption signal , the carbon concentrations of each known 13 The slope value is obtained by linear fitting of CH4 concentration and the second harmonic peak of the absorption signal : (2) Establishing an analysis model Modulate the laser light source so that the output center wavelength of the laser light source is and The laser signal is recorded as and The second harmonic peak of the absorption signal at and ,but 13 CH4, 12 The relationship between CH4 concentration and slope value: in, express 13 CH4 concentration; express 12 CH4 concentration.

6. A gas logging device containing carbon isotope methane for implementing the method according to any one of claims 1 to 5, characterized in that: include: A wellhead gas connection module, which is used to transport the gas at the wellhead to the Fourier transform infrared spectroscopy absorption multi-component gas detection system; A Fourier transform infrared spectroscopy absorption multi-component gas detection system is used to obtain infrared absorption spectrum data of wellhead gas; the Fourier transform infrared spectroscopy absorption multi-component gas detection system is connected to a tunable laser carbon isotope methane gas detection system; Tunable laser carbon isotope methane gas detection system, used to obtain the absorbance data of carbon isotope methane in wellhead gas at the central wavelength; A temperature and pressure detector (11), wherein the temperature and pressure detector (11) is installed on the tunable laser carbon isotope methane gas detection system and is used to monitor the temperature and pressure inside the tunable laser carbon isotope methane gas detection system in real time; A data processing and control module (12), the data processing and control module (12) being connected to the Fourier transform infrared spectroscopy absorption multi-component gas detection system, the tunable laser carbon isotope methane gas detection system, the temperature and pressure detector (11) and the telemetry information module (14), for calculating the components and concentration values ​​of the gas to be detected based on infrared absorption spectrum data, absorbance data, temperature and pressure data, and transmitting the calculated values ​​to a master control room via the telemetry information module (14).

7. The gas logging device containing carbon isotope methane according to claim 6, characterized in that: The wellhead gas connection module comprises a connection pipe (1) and a valve (2); the wellhead gas enters the Fourier transform infrared spectroscopy absorption multi-component gas detection system through the connection pipe (1) and is controlled on and off by the valve (2).

8. The gas logging device containing carbon isotope methane according to claim 7, characterized in that: The Fourier transform infrared spectroscopy absorption multi-component gas detection system comprises an infrared light source and an interferometer (4), a biconical gas pool (5) and an infrared detector (6), wherein the infrared light source and the interferometer (4) and the infrared detector (6) are arranged at two ends of the biconical gas pool (5); the biconical gas pool (5) is provided with an air inlet (3), and the air inlet (3) is connected to a connecting pipe (1); the outlet of the biconical gas pool (5) is connected to a tunable laser carbon isotope methane gas detection system; the infrared light source and the interferometer (4) and the infrared detector (6) are all interacting with a data processing and control module (12).

9. The gas logging device containing carbon isotope methane according to claim 6 or 7, characterized in that: The tunable laser carbon isotope methane gas detection system comprises an infrared laser light source (7), a long optical path gas pool (8) and a laser detector (13); the mid-infrared laser light source (7) and the laser detector (13) are arranged at two ends of the long optical path gas pool (8); the long optical path gas pool (8) is provided with a gas outlet (10), and the detected gas flows out through the gas outlet (10); the inlet of the long optical path gas pool (8) is connected to the Fourier transform infrared spectroscopy absorption multi-component gas detection system; and the mid-infrared laser light source (7) and the laser detector (13) both interact with the data processing and control module (12).

10. The gas logging device containing carbon isotope methane according to claim 6, characterized in that: The data processing and control module (12) is provided with a display screen (9) for displaying the components of the gas to be measured and its concentration value.

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