Method for enriching and purifying biological marker compound in high-postmature soluble organic matter

Abstract

The invention provides a method for enriching and purifying a biological marker compound in a high-postmature soluble organic matter. According to the method, a methanol saturated solution of urea is utilized for complexing and purifying n-alkane in the high-postmature soluble organic matter and simultaneously enriching the biological marker compound. The method comprises the following steps: (a) preprocessing a high-postmature soluble organic matter sample, so as to obtain a saturated hydrocarbon sample; (b) concentrating the saturated hydrocarbon sample to a half-dry state, and adding the saturated hydrocarbon sample into a mixed solution of normal hexane and acetone, so as to obtain a mixed solution B; (c) adding the methanol saturated solution of urea into the mixed solution B while stirring, so as to obtain a solution C; (d) filtering the mixed solution C, so as to obtain filtrate and urea; (e) blow-drying the filtrate, carrying out drip washing by virtue of normal hexane, concentrating the filtrate into an automatic feeding bottle, and carrying out determination by virtue of GC-MS; and (f) dissolving urea with deionized water, carrying out extracting by virtue of normal hexane, concentrating extracted liquid into the automatic feeding bottle, and carrying out determination by virtue of GC-MS.

Description

technical field [0001] The invention relates to a method for enriching and purifying biomarker compounds in highly overmature soluble organic matter. Background technique [0002] The components in crude oil or chloroform bitumen "A" in the stage of high-over-mature evolution are mainly normal alkanes, with a content of over 90%, while the concentration of isomer compounds is generally very low. When biomarker compounds in over-mature soluble organic matter are used, it is often impossible to accurately analyze the composition of sterane and terpane biomarker compounds, let alone detect their relative concentrations. The specific reasons are mainly reflected in the following two aspects: [0003] (1) The content of biomarker compounds is too low to be detected; [0004] (2) The peak shape of normal alkanes is too high, which affects the peak shape of biomarker compounds. [0005] Therefore, this has caused difficulties in the identification and quantification of biomarker ...

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Problems solved by technology

[0003] (1) The content of biomarker compounds is too low to be detected;

[0004] (2) The peak shape of normal alkanes is too high, which affects the peak shape of biomarker compounds

[0005] Therefore, this has caused difficulties in the identification and quantification of biomarker compounds in highly over-mature soluble organic matter, and has also limited the application of geochemical techniques in oil and gas exploration in deep layers under high temperature and high pressure conditions.

[0006] The general laboratory treatment method is to use 5A molecular sieve to remove normal alkanes in soluble organic matter, but this method has two defects. One is that the process of obtaining isoparaffins needs to be pressurized, which increases the number of experimenters. The risk of operation; on the other hand, the defect is that in the process of obtaining n-alkanes in 5A molecular sieve, it is necessary to destroy the molecular sieve, and the large amount of heat energy generated in the destruction process affects the content and structure of n-alkanes to a certain extent

[0007] There are also reports on experimental methods for purifying n-alkanes in the existing literature, but there is no detailed test technology for the enrichment and purification of biomarker compounds in highly over-mature soluble organic matter

For example, in the process of making chromatographic samples, the existence of a large number of isomers will make the integration results of n-alkanes inaccurate. Shiping Xu (Shiping Xu, Yongge Sun. Animproved method for the micro-separation of straight chain and branched / cyclic alkanes: Ureainclusion paper layer chromatography.Organic Geochemistry,2005(36):1334–1338), etc. and Xu Fenfang (Xu Fenfang.Paper chromatography of alkanes and urea complexation in sedimentary rocks and petroleum. Geochemistry,1984(2):186-188), etc. Use paper chromatography to separate normal and isoparaffins, but the amount of sample obtained is very small, and light hydrocarbons are easily lost, and the main peak carbon of the sample will also change.

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