CN-122017101-A - Method for judging natural gas stratum source by gas chromatography-mass spectrometry

Abstract

The invention discloses a method for judging the source of a natural gas stratum by utilizing a gas chromatography-mass spectrometry, which comprises the steps of firstly sampling a natural gas sample from a known stratum and a natural gas sample from an unknown source, secondly detecting a natural gas standard gas, the natural gas sample from the known stratum and the natural gas sample from the unknown source through a gas chromatography-mass spectrometry combined instrument, thirdly constructing a control fingerprint of C 6 、C 7 、C 8 components of the natural gas sample from the known stratum according to a detection result, and fourthly comparing the control fingerprint of the natural gas sample from the unknown source with the natural gas sample from the known stratum and the proportion of compounds to judge whether the natural gas sample from the unknown source comes from the stratum of the natural gas sample from the known source. By taking the C 6 、C 7 、C 8 component in the natural gas as a detection target and taking the micro component in the natural gas as a bridge for connecting the gas and the source, the stratum source of the natural gas can be rapidly and accurately identified.

Inventors

• REN ZHAOYAN
• WU YONGHUA
• ZHANG ZHENZHU
• ZHANG TINGTING
• ZHANG YUTONG
• YANG YONGXIA
• XIANG YUQI
• Jiang Dunyu
• ZHANG QI
• ZHOU JUNYOU
• CHEN YUPING
• WANG HUAPENG
• WANG XINGHUA
• GONG ZHAOBO
• LUO XIAOJING
• YAN ZHONG
• LIU XIANGJUN
• LIN LILI
• WANG YI

Assignees

• 新疆石油管理局有限公司
• 中国石油天然气股份有限公司
• 中国石油天然气集团有限公司

Dates

Publication Date

20260512

Application Date

20241111

Claims (5)

1. 1. A method for judging natural gas stratum sources by using a gas chromatography-mass spectrometry method is characterized in that: step one, sampling a natural gas sample from a known stratum and a natural gas sample from an unknown stratum, wherein a plurality of natural gas samples from the known stratum are collected; detecting natural gas standard gas, a natural gas sample from a known stratum and a natural gas sample from an unknown source by a gas chromatograph-mass spectrometer; Step three, constructing a control fingerprint of a C 6 、C 7 、C 8 component of a natural gas sample from a known stratum according to a detection result, wherein the peak area of each fingerprint peak in the control fingerprint is more than 3%; step four, after the gas chromatography-mass spectrometry detection is carried out on the natural gas sample with unknown source, a total ion flow diagram of a C 6 、C 7 、C 8 component of the sample is obtained, the total ion flow diagram is compared with a control fingerprint of C 6 、C 7 、C 8 of the natural gas sample with known stratum source in the step three, if the similarity with the control fingerprint is larger than a set value, the next step is carried out, otherwise, the natural gas sample with unknown source can be judged, and the stratum not from the natural gas sample with known source is not obtained; Step five, respectively calculating the total concentration of the C 6 component, the C 7 component and the C 8 component in a plurality of natural gas samples from known stratum sources, calculating the ratio of C 6 /C 7 to C 7 /C 8 , respectively obtaining the average value of the ratio of C 6 /C 7 to C 7 /C 8 , Calculating the values of the unknown source natural gas samples C 6 /C 7 and C 7 /C 8 , if the values of the unknown source natural gas samples C 6 /C 7 and C 7 /C 8 are respectively within +/-10% of the mean value of the known stratum source natural gas samples C 6 /C 7 and C 7 /C 8 , entering the next step, otherwise, judging that the unknown source natural gas samples are not from the stratum of the known source natural gas samples; Step six, respectively calculating n-hexane/methylcyclohexane and methylcyclohexane/n-octane ratios in a plurality of natural gas samples from known stratum sources, and respectively obtaining the average value of the n-hexane/methylcyclohexane and methylcyclohexane/n-octane ratios; Calculating the values of n-hexane/methylcyclohexane and methylcyclohexane/n-octane ratios of the natural gas samples of unknown sources, if the n-hexane/methylcyclohexane and methylcyclohexane/n-octane ratios of the natural gas samples of unknown sources are respectively within +/-10% of the average value of the n-hexane/methylcyclohexane and methylcyclohexane/n-octane ratios of the natural gas samples of known stratum sources, entering the next step, otherwise, judging that the natural gas samples of unknown sources are not from the stratum of the natural gas samples of known sources; and step seven, when the requirements of the steps four to six are simultaneously met, determining that the natural gas sample with unknown source is derived from the stratum of the natural gas sample with known source.
2. 2. The method for judging the source of the natural gas stratum by utilizing the gas chromatography-mass spectrometry according to claim 1, wherein in the second step, the chromatographic conditions are chromatographic column TG-5MS,60m multiplied by 0.25mm multiplied by 1.0 mu m, carrier gas, high-purity helium, flow rate, sample inlet temperature, 200 ℃ and split sample injection, wherein the split ratio is 10:1; The temperature programming condition comprises an initial temperature of 40 ℃ and a temperature of 5 ℃ per minute to 150 ℃, wherein the temperature is kept for 4min, an EI ionization source is used for electron ionization under 70eV, the temperature of the ion source is 250 ℃, the temperature of a transmission line is 220 ℃, the solvent is delayed for 4min, the scanning range is 45-150 amu, and the sample injection amount is 100 mu L.
3. 3. The method of claim 1, wherein in the fourth step, if the similarity with the reference fingerprint is greater than 0.9, the next step is performed, otherwise, the unknown source natural gas sample may be determined, and the formation not derived from the known source natural gas sample may be determined.
4. 4. The method for determining the source of a natural gas formation by gas chromatography mass spectrometry according to claim 1, wherein the detection parameters comprise C 6 components, specifically n-hexane, 2-dimethylbutane, 3-methylpentane, 2-methylpentane, benzene and cyclohexane; A C 7 component, specifically including n-heptane, methylcyclohexane, and toluene; C 8 component, specifically including n-octane, 2-methyl heptane, 2-dimethylhexane, 1, 2-dimethylcyclohexane, o-xylene, ethylbenzene, m-xylene, p-xylene and ethylcyclohexane.
5. 5. The method for determining natural gas formation source by gas chromatography-mass spectrometry according to claim 4, wherein in the second step, the quantitative ions and auxiliary ions of each detection parameter are respectively,

Description

Method for judging natural gas stratum source by gas chromatography-mass spectrometry Technical Field The invention belongs to the technical field of natural gas exploration, and particularly relates to a method for judging natural gas stratum sources by using a gas chromatography-mass spectrometry. Background Natural gas is a clean, low-carbon and environment-friendly green energy, and the proportion of the natural gas in the energy structure of China is larger and larger. In the process of natural gas exploration and development, how to distinguish natural gas sources of different layers so as to provide key information for exploration decisions has become a key difficult problem for restricting natural gas exploration and development. Chinese patent CN 117216588A discloses a method for identifying a natural gas source, by calculating the natural gas maturity of the natural gas to be identified by existing natural gas data and hydrocarbon source rock data, and obtaining the gas source of the natural gas to be identified by comparing the natural gas type with the hydrocarbon source rock organic matter type, the ethane carbon isotope with the hydrocarbon source rock organic carbon isotope, the natural gas component with the retentate gas component, and the natural gas isotope with the retentate gas isotope. Chinese patent CN 104749322B provides a method for identifying a high-over-maturity natural gas source, and by testing and analyzing geochemical characteristics of natural gas, reservoir bitumen and hydrocarbon source rock, a causal relationship between natural gas-reservoir bitumen-hydrocarbon source rock is established, and the high-over-maturity natural gas source is identified. Chinese patent CN 114255828A provides a method and a device for judging the cause and source of natural gas in a complex high evolution multi-source gas reservoir by acquiring alkane series carbon isotope data of natural gas samples in different strata and judging the cause and source of the natural gas samples to be tested according to ethane carbon isotope data and the difference between the ethane carbon isotope data and methane carbon isotope data in the alkane series carbon isotope data of the natural gas samples to be tested. These methods mainly utilize biomarker compounds and isotopes of carbon and hydrogen in natural gas. The biomarker compound needs to extract saturated hydrocarbon, aromatic hydrocarbon, asphaltene and non-hydrocarbon components, and the biomarker compound analysis is carried out on a certain component, so that a corresponding relation is constructed, a rock sample or crude oil is needed as a research basis, the analysis time is long, and the influence of maturity is easy to realize. The carbon and hydrogen isotopes need expensive isotope mass spectrometers, and because of the complex source of natural gas, the carbon and hydrogen isotopes often have inversion or reverse characterization anomalies. Disclosure of Invention The invention aims to provide a method for judging the stratum source of natural gas by utilizing a gas chromatography-mass spectrometry method, which can rapidly and accurately identify the stratum source of natural gas. The invention aims at realizing the following technical means, a method for judging the source of a natural gas stratum by utilizing a gas chromatography-mass spectrometry, Step one, sampling a natural gas sample from a known stratum and a natural gas sample from an unknown stratum, wherein a plurality of natural gas samples from the known stratum are collected; detecting natural gas standard gas, a natural gas sample from a known stratum and a natural gas sample from an unknown source by a gas chromatograph-mass spectrometer; The detection parameters comprise C6 components, and specifically comprise n-hexane, 2-dimethylbutane, 3-methylpentane, 2-methylpentane, benzene and cyclohexane; a C7 component, specifically including n-heptane, methylcyclohexane, and toluene; and C8 components, including n-octane, 2-methyl heptane, 2-dimethyl hexane, 1, 2-dimethyl cyclohexane, o-xylene, ethylbenzene, m-xylene, p-xylene and ethyl cyclohexane. Step three, constructing a control fingerprint of a C 6、C7、C8 component of a natural gas sample from a known stratum according to a detection result, wherein the peak area of each fingerprint peak in the control fingerprint is more than 3%; step four, after the gas chromatography-mass spectrometry detection is carried out on the natural gas sample with unknown source, a total ion flow diagram of a C 6、C7、C8 component of the sample is obtained, the total ion flow diagram is compared with a control fingerprint of C 6、C7、C8 of the natural gas sample with known stratum source in the step three, if the similarity with the control fingerprint is larger than a set value, the next step is carried out, otherwise, the natural gas sample with unknown source can be judged, and the stratum not from the natural gas sample with known source is not obta