Crude oil parent material deposition environment identification method

Abstract

The invention discloses a crude oil parent material sedimentary environment identification method, and relates to the technical field of petroleum geological exploration. The invention relates to a crude oil parent material deposition environment identification method, which comprises: reference substance treatment: separating crude oil from different deposition environments, carrying out chromatography-mass spectrometry analysis and chromatography-isotope-mass spectrometry analysis on the separated product to obtain a Pr / Ph value and a 13C isotope of fluorene, and establishing an identification plate; sample treatment: separating the sample crude oil to be identified, and carrying out chromatography-mass spectrometry and chromatography-isotope-mass spectrometry on the separated product to obtain a Pr / Ph value and 13C isotope of fluorene; and sample identification: plumbing the Pr / Ph value of the crude oil sample to be identified and the 13C isotope of fluorene into the identification chart for identification. The method is less affected by secondary effects, the accuracy of crude oil parent material deposition environment analysis is improved, and deposition basin oil source comparison and oil-gas migration path research are facilitated.

Description

Technical Field

[0001] The invention relates to the technical field of petroleum geological exploration, and in particular to a method for identifying a crude oil parent material deposition environment. Background Art

[0002] There are obvious differences in geochemical characteristics between crude oils from different parent materials. Accurate identification of the parent material depositional environment of crude oil is of great significance for oil source comparison, determination of oil and gas migration paths and reservoir formation patterns. On the one hand, the original source of crude oil can be determined by analyzing biomarker compounds, carbon isotope ratios, and specific organic compounds (such as odd-even dominance of n-alkanes, Pr / Ph values, etc.) in crude oil. This helps to identify specific depositional environments, such as deepwater anoxic environments or shallow water oxygen-rich environments, so as to determine whether algae, bacteria or terrestrial vegetation are the main sources of organic matter. This comparison is the basis for determining whether the oil in the oil and gas field comes from the same source rock. On the other hand, understanding the parent material depositional environment of crude oil helps to infer the movement trajectory of oil and gas in the crust. Different depositional environments may produce hydrocarbons of different properties, and these characteristics can indicate the flow direction and distance of oil and gas in the formation. For example, oil formed from a deepwater environment may migrate upward through deep structural channels, while oil formed from terrestrial sediments may migrate laterally along river paleochannels or sand bodies. On the other hand, the accumulation mode involves how oil and gas accumulate in a specific geological structure. The identification of the parent material environment helps to understand the conditions for the formation of oil and gas reservoirs, such as whether they are in situ accumulation (source oil reservoir) or accumulation after long-distance migration. Different sedimentary environments have a direct impact on the requirements of caprocks and the formation mechanism of closures, which is crucial for exploring new oil and gas reservoirs and evaluating the potential of existing oil and gas reservoirs. In addition, accurate parent material environment analysis can guide exploration work, determine which areas are most likely to contain rich source rocks, and predict possible oil and gas accumulation zones. This helps to optimize drilling locations and reduce exploration risks and costs.

[0003] Conventional geochemical methods use a combination of biomarker compounds to identify the depositional environment of crude oil parent materials, such as a method for analyzing oil and gas geochemical characteristics disclosed in publication number CN105572324A, which analyzes the environment of crude oil parent materials by 1) statistically analyzing the physical properties of crude oil, 2) detecting the composition of light hydrocarbons in crude oil, 3) comparing the molecular weight hydrocarbons of crude oil, 4) detecting biomarker compounds in crude oil, and 5) analyzing the geochemical characteristics of natural gas. However, such analysis methods are easily affected by secondary effects such as maturity and biodegradation. Therefore, there is an urgent need for a method that can accurately identify the depositional environment of crude oil parent materials and is less affected by secondary effects, and has universal applicability. Summary of the invention

[0004] The technical problem to be solved by the present invention is that the existing methods for identifying the depositional environment of crude oil parent material are easily affected by secondary effects such as maturity and biodegradation. The purpose is to provide a method for identifying the depositional environment of crude oil parent material, which is less affected by secondary effects, improves the accuracy of crude oil parent material depositional environment analysis, and facilitates the comparison of oil sources in sedimentary basins and the study of oil and gas migration paths.

[0005] The present invention is achieved through the following technical solutions: A method for identifying a crude oil parent material deposition environment comprises the following steps: Reference material treatment: Crude oils from different sedimentary environments were separated, and the separated products were subjected to chromatography-mass spectrometry and chromatography-isotope-mass spectrometry to obtain the Pr / Ph value and fluorene 13 C isotope, establish identification plate; Sample processing: Separate the crude oil sample to be identified, and perform chromatography-mass spectrometry and chromatography-isotope-mass spectrometry on the separated products to obtain the Pr / Ph value and fluorene 13 C isotope; Sample identification: The Pr / Ph value of the crude oil to be identified and the 13 Project the C isotope onto the identification plate for identification.

[0006] As a possible design, the above-mentioned control sample treatment includes the following steps: Crude oils from different sedimentary environments are separated to obtain saturated hydrocarbons and aromatic hydrocarbons of different crude oils; The saturated hydrocarbons were subjected to chromatography-mass spectrometry analysis (GC-MS analysis) to obtain the Pr / Ph value; Aromatic hydrocarbons were separated to obtain dicyclic aromatic hydrocarbon compounds, and the fluorene was identified and measured by chromatography-isotope-mass spectrometry (GC-IR-MS). 13 C isotope; Establish 13 The cross plot of C isotope and Pr / Ph value is used to project points on crude oils originating from different sedimentary environments, divide the regional ranges of different environments, and establish an identification map.

[0007] As a possible design, the above sample processing includes the following steps: Separating the sample crude oil to be identified to obtain saturated hydrocarbons and aromatic hydrocarbons of the sample to be identified; The saturated hydrocarbons were subjected to chromatography-mass spectrometry analysis to obtain the Pr / Ph value; Aromatic hydrocarbons were separated to obtain dicyclic aromatic hydrocarbon compounds, and the fluorene was identified and measured by chromatography-isotope-mass spectrometry. 13 C isotope.

[0008] As a possible design, the above crude oil separation includes the following steps: The crude oil was dissolved in petroleum ether, and after settling, asphaltene and sample concentrate were filtered out; The sample concentrate is separated into saturated hydrocarbons and aromatic hydrocarbons by chromatography.

[0009] As a possible design, the above aromatic hydrocarbon separation includes the following steps: respectively preparing gradient mixed solvents with different petroleum ether / dichloromethane volume ratios; Fill the chromatography column with chromatography silica gel, then add alumina in an equal volume to the chromatography silica gel, wet the chromatography column with petroleum ether, and transfer the aromatic hydrocarbons into the chromatography column; When the sample liquid surface reaches the top interface of the stationary phase, the mixed solutions with different petroleum ether / dichloromethane volume ratios are used for flushing in the order of petroleum ether concentration from high to low.

[0010] As a possible design, the above-mentioned gradient mixed solvents with different petroleum ether / dichloromethane volume ratios include gradient mixed solvents with petroleum ether / dichloromethane volume ratios of 93:7, 9:1, 3:1, and 0:100, respectively.

[0011] As a possible design, when the sample liquid surface reaches the top interface of the stationary phase, a mixed solution of petroleum ether / dichloromethane with a volume ratio of 93:7 is used to wash the monocyclic aromatic hydrocarbon compounds multiple times; When the last mixed solution of petroleum ether / dichloromethane with a volume ratio of 93:7 enters the stationary phase, the solution in the chromatography column is emptied; Use a mixed solution of petroleum ether / dichloromethane with a volume ratio of 9:1 to wash the dicyclic aromatic hydrocarbon compounds multiple times; When the last mixed solution of petroleum ether / dichloromethane with a volume ratio of 9:1 enters the stationary phase, the solution in the chromatography column is emptied; The tricyclic aromatic hydrocarbon compounds were rinsed several times using a mixed solution of petroleum ether / dichloromethane with a volume ratio of 3:1.

[0012] As a possible design, the above establishment 13 The cross plot of C isotopes and Pr / Ph values ​​is processed as follows: by 13 A cross plot was established with C isotope as the ordinate and Pr / Ph value as the abscissa.

[0013] As a possible design, the above-mentioned establishment of the recognition plate is processed as follows: Crude oil from different sedimentary environments is projected into the intersection map to divide the regional ranges of different environments.

[0014] As a possible design, the above identification plate includes 5 areas: Area 1 13The C isotope ≤ -28‰ and Pr / Ph < 1.5 indicate that the sedimentary environment of the crude oil parent material is marine and is sourced from lower aquatic organisms; of Region 2 13 The C isotope ≤ -26‰ and 1.5 < Pr / Ph ≤ 2 indicate a saline lake facies and are sourced from algae and bacteria; of Region 3 13 The C isotope ≤ -26‰ and Pr / Ph > 2 indicate a fluvial / deltaic / freshwater lake facies and are sourced from mixed organic matter; of Region 4 13 The C isotope > -28‰ and Pr / Ph ≤ 1.5 indicate a transitional marine - continental facies and are sourced from higher plants; of Region 5 13 The C isotope > -26‰ and Pr / Ph > 1.5 indicate a shore - marsh facies and are sourced from higher plants.

[0015] Compared with the prior art, the present invention has the following advantages and beneficial effects: By using the 13 C isotope and Pr / Ph value of fluorene in crude oil for judgment and identification, the sedimentary environment of the crude oil parent material can be accurately obtained, with high accuracy and universality. It solves the problem of identifying the sedimentary environment of the crude oil parent material affected by secondary effects such as maturity and biodegradation, and provides favorable technical support for oil - source correlation, hydrocarbon charging pathways, and hydrocarbon accumulation research. Brief Description of the Drawings

[0016] To more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention, and therefore should not be regarded as limiting the scope. For those of ordinary skill in the art, without creative efforts, other relevant drawings can also be obtained based on these drawings. In the drawings: Figure 1 is the projection point diagram of the standard samples of crude oil sourced from different sedimentary environments in Example 1 of the present invention in the cross - plot of 13 C isotope and Pr / Ph value of fluorene; Figure 2 is the identification diagram of the sedimentary environment of the crude oil parent material in Example 1 of the present invention; Figure 3 is the identification result diagram of Example 1 of the present invention. Detailed Embodiments

[0017] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is further described in detail below in conjunction with examples and drawings. The illustrative embodiments of the present invention and their description are only used to explain the present invention and are not intended to limit the present invention. If specific conditions are not specified in the examples, they are carried out according to conventional conditions or conditions recommended by the manufacturer. If the manufacturer is not specified for the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0018] Based on the existing knowledge, the identification of crude oil parent material sedimentary environment is mainly based on the combination of biomarker compounds, which is easily affected by secondary effects such as maturity and biodegradation.

[0019] Therefore, the present invention provides a method for identifying the sedimentary environment of crude oil parent materials. Based on the fact that aromatic hydrocarbons are commonly found in crude oil and sedimentary extracted species and have a stable structure, they are not easily affected by secondary effects and can be used as a good indicator of the source of organic parent materials and their sedimentary environment. In addition, the isotopic composition of the compound is mainly controlled by the source of the parent material and is less affected by secondary effects. Fluorene series compounds are aromatic hydrocarbons and are widely distributed in crude oils from different parent materials. The inventors have found that their monomer isotopic composition can be used to identify the sedimentary environment of crude oil parent materials, and they have the advantages of high stability and not being easily affected by maturity and secondary effects, which has a great indicative significance for the sedimentary environment. Therefore, the inventors chose to identify the sedimentary environment of crude oil parent materials through the isotopic composition of fluorene. 13 C isotope combined with other biomarker compound characteristics to establish a method for identifying the sedimentary environment of crude oil parent material.

[0020] A method for identifying a crude oil parent material deposition environment comprises the following steps: Reference material treatment: Crude oils from different sedimentary environments were separated, and the separated products were subjected to chromatography-mass spectrometry and chromatography-isotope-mass spectrometry to obtain the Pr / Ph value and fluorene 13 C isotope, establish identification plate; Sample processing: Separate the crude oil sample to be identified, and perform chromatography-mass spectrometry and chromatography-isotope-mass spectrometry on the separated products to obtain the Pr / Ph value and fluorene 13 C isotope; Sample identification: The Pr / Ph value of the crude oil to be identified and the 13 Project the C isotope onto the identification plate for identification.

[0021] By first separating crude oils from different sedimentary environments, the separated products of each crude oil were subjected to chromatography-mass spectrometry analysis and chromatography-isotope-mass spectrometry analysis to obtain the Pr / Ph value and the 13 C isotope, and based on the Pr / Ph value and the 13 C isotope to establish the identification plate; then the sample to be identified is treated in the same way, and the Pr / Ph value of the sample to be identified and the13 By inputting the C isotope into the identification plate and comparing it with the identification plate of the reference sample, the parent material deposition environment of the sample crude oil can be determined.

[0022] As a possible design, the above-mentioned control sample treatment includes the following steps: Crude oils from different sedimentary environments are separated to obtain saturated hydrocarbons and aromatic hydrocarbons of different crude oils; The saturated hydrocarbons were subjected to chromatography-mass spectrometry analysis to obtain the Pr / Ph value; Aromatic hydrocarbons were separated to obtain dicyclic aromatic hydrocarbon compounds, and the fluorene was identified and measured by chromatography-isotope-mass spectrometry. 13 C isotope; Establish 13 The cross plot of C isotope and Pr / Ph value is used to project points on crude oils originating from different sedimentary environments, divide the regional ranges of different environments, and establish an identification map.

[0023] The crude oil is separated, the saturated hydrocarbons are analyzed by chromatography to obtain the Pr / Ph value, and the dicyclic aromatic hydrocarbons are separated from the aromatic hydrocarbons for measurement. 13 C isotope, using 13 The C isotope and Pr / Ph value are intersected to obtain the identification chart of different environmental regions, which is convenient for the comparison of samples to be identified. Aromatic hydrocarbons only have benzene rings, and the compound fluorene contains two benzene rings. After research, the inventor found that selecting dicyclic aromatic hydrocarbon compounds for measurement can accurately measure the fluorene 13 C isotope.

[0024] As a possible design, the above sample processing includes the following steps: Separating the sample crude oil to be identified to obtain saturated hydrocarbons and aromatic hydrocarbons of the sample to be identified; The saturated hydrocarbons were subjected to chromatography-mass spectrometry analysis to obtain the Pr / Ph value; Aromatic hydrocarbons were separated to obtain dicyclic aromatic hydrocarbon compounds, and the fluorene was identified and measured by chromatography-isotope-mass spectrometry. 13 C isotope.

[0025] As a possible design, the above crude oil separation includes the following steps: The crude oil was dissolved in petroleum ether, and after settling, asphaltene and sample concentrate were filtered out; The sample concentrate is separated into saturated hydrocarbons and aromatic hydrocarbons by chromatography.

[0026] Preferably, the above crude oil separation comprises the following steps: Crude oil and petroleum ether are mixed and dissolved in a solid-liquid ratio of (30-50): (20-40), and asphaltene and sample concentrate are filtered out after standing and settling; Weigh silica gel and neutral alumina in a weight ratio of (3-4): (2-3): (30-50) to crude oil, fill the bottom of the chromatography column with an appropriate amount of absorbent cotton, first add silica gel, then add neutral alumina, tap gently to make the stationary phase fill evenly, and add an appropriate amount of petroleum ether to moisten; When the petroleum ether liquid level reaches the top interface of the neutral alumina stationary phase, transfer the sample concentrate into the chromatography column. When the sample liquid level reaches the top interface of the stationary phase, weigh petroleum ether with a solid-liquid ratio of (30-40): (30-50) to crude oil, and wash the saturated hydrocarbons 6 to 8 times in total; When the liquid level of the last petroleum ether washing liquid reaches the top interface of alumina, weigh a petroleum ether / dichloromethane mixed solution with a solid-liquid ratio of 20: (30-50) to crude oil and wash the aromatic hydrocarbons four times. The volume ratio of petroleum ether / dichloromethane in the petroleum ether / dichloromethane mixed solution is 1:2, and collect the aromatic hydrocarbons.

[0027] Preferably, the saturated hydrocarbon is flushed in an amount of 5 ml each time.

[0028] Preferably, the mixed solution is flushed in an amount of 5 ml each time. When 5 ml of the mixed solution flows into 3 ml of the stationary phase for the first time, the collection container for saturated hydrocarbons is removed and replaced with a collection container for aromatic hydrocarbons.

[0029] As a possible design, the above aromatic hydrocarbon separation includes the following steps: respectively preparing gradient mixed solvents with different petroleum ether / dichloromethane volume ratios; Fill the chromatography column with chromatography silica gel, then add alumina in an equal volume to the chromatography silica gel, wet the chromatography column with petroleum ether, and transfer the aromatic hydrocarbons into the chromatography column; When the sample liquid surface reaches the top interface of the stationary phase, the mixed solutions with different petroleum ether / dichloromethane volume ratios are used for flushing in the order of petroleum ether concentration from high to low.

[0030] Preferably, the above aromatic hydrocarbon separation comprises the following steps: Gradient mixed solvents with petroleum ether / dichloromethane volume ratios of 93:7, 9:1, 3:1, and 0:100 were prepared respectively; Weigh silica gel and neutral alumina in a weight ratio of (1-1.5): (2.5-3), fill a clean chromatography column with silica gel, add Sigma alumina (equal volume to silica gel), wet the chromatography column with an appropriate amount of petroleum ether, and transfer the concentrated aromatic hydrocarbon components in the previous step into the chromatography column; When the sample liquid surface reaches the top interface of the stationary phase, use 6 ml of a mixed solution of petroleum ether / dichloromethane with a volume ratio of 93:7, 1 ml each time for a total of 6 times to wash the monocyclic aromatic hydrocarbon compounds; When the last 1 ml of the mixed solution of petroleum ether / dichloromethane (volume ratio 93:7) enters the stationary phase, empty the solution in the chromatography column; Use 8 ml of a mixture of petroleum ether and dichloromethane (volume ratio: 9:1) to wash the dicyclic aromatic hydrocarbons eight times with 1 ml each time; When the last 1 ml of the mixed solution of petroleum ether / dichloromethane (volume ratio 9:1) enters the stationary phase, empty the solution in the chromatography column; Use 8 ml of a mixed solution of petroleum ether and dichloromethane with a volume ratio of 3:1, and rinse the tricyclic aromatic hydrocarbons 8 times with 1 ml each time.

[0031] As a possible design, the above-mentioned gradient mixed solvents with different petroleum ether / dichloromethane volume ratios include gradient mixed solvents with petroleum ether / dichloromethane volume ratios of 93:7, 9:1, 3:1, and 0:100, respectively.

[0032] As a possible design, when the sample liquid surface reaches the top interface of the stationary phase, a mixed solution of petroleum ether / dichloromethane with a volume ratio of 93:7 is used to wash the monocyclic aromatic hydrocarbon compounds multiple times; When the last mixed solution of petroleum ether / dichloromethane with a volume ratio of 93:7 enters the stationary phase, the solution in the chromatography column is emptied; Use a mixed solution of petroleum ether / dichloromethane with a volume ratio of 9:1 to wash the dicyclic aromatic hydrocarbon compounds multiple times; When the last mixed solution of petroleum ether / dichloromethane with a volume ratio of 9:1 enters the stationary phase, the solution in the chromatography column is emptied; The tricyclic aromatic hydrocarbon compounds were rinsed several times using a mixed solution of petroleum ether / dichloromethane with a volume ratio of 3:1.

[0033] As a possible design, the above establishment 13 The cross plot of C isotopes and Pr / Ph values ​​is processed as follows: by 13 A cross plot was established with C isotope as the ordinate and Pr / Ph value as the abscissa.

[0034] As a possible design, the above-mentioned establishment of the recognition plate is processed as follows: Crude oil from different sedimentary environments is projected into the intersection map to divide the regional ranges of different environments.

[0035] Specifically, 13 C isotope and Pr / Ph value are used as the ordinate and abscissa to establish a cross plot; standard samples from five basins are inserted (for example: Table 1), because the parent material depositional environment corresponding to these five groups of crude oil samples is certain, so the samples to be identified are inserted into this range to indicate the depositional environment.

[0036] As a possible design, the above discrimination chart plate includes five regions. For region 1, 13 The C isotope ≤ -28‰ and Pr / Ph ≤ 1.5, indicating that the sedimentary environment of the crude oil parent material is marine and is sourced from lower aquatic organisms. For region 2, 13 The C isotope ≤ -26‰ and 1.5 < Pr / Ph < 2, indicating a brackish lake facies and being sourced from algae and bacteria. For region 3, 13 The C isotope ≤ -26‰ and Pr / Ph > 2, indicating a fluvial / deltaic / freshwater lake facies and being sourced from mixed organic matter. For region 4, 13 The C isotope > -28‰ and Pr / Ph ≤ 1.5, indicating a marine - continental transitional facies and being mainly sourced from higher plants. For region 5, 13 The C isotope > -26‰ and Pr / Ph > 1.5, indicating a shore - marsh facies and being sourced from higher plants.

[0037] Preferably, the above - mentioned region 4 includes sources from higher plants, algae, and bacteria.

[0038] Example 1

[0039] A method for identifying the sedimentary environment of crude oil parent material includes the following steps: S1. Control sample treatment: S11. Separate the crude oils (including those from the Ordos Basin, Beibu Gulf Basin, Tarim Basin, Termit Basin, and Bongor Basin) sourced from different sedimentary environments to obtain the saturated hydrocarbons and aromatic hydrocarbons of different crude oils. Among them, the separation of different crude oils includes the following steps: S111. Put 30 - 50 mg of standard - sample crude oil into a reagent bottle, add 30 ml of petroleum ether, dissolve it by ultrasonic treatment, filter the asphaltene after standing and precipitation. S112. Stuff an appropriate amount of absorbent cotton at the bottom of the chromatography column, first add 3 - 4 g of silica gel, then add 2 - 3 g of neutral alumina, gently tap to make the stationary phase fill evenly, and add an appropriate amount of petroleum ether to moisten it. S113. When the petroleum ether liquid level reaches the top interface of the neutral alumina stationary phase, transfer the sample concentrate into the chromatography column. When the sample liquid level reaches the top interface of the stationary phase, use 30 - 40 ml of petroleum ether to wash the saturated hydrocarbons 6 - 8 times with 5 ml each time. S114. When the last 5 ml petroleum ether eluent reaches the top interface of alumina, rinse the aromatic hydrocarbons with 20 ml of petroleum ether / dichloromethane (1:2) mixed solvent 5 ml each time for a total of 4 times. When the first 5 ml mixed solution flows into 3 ml of the stationary phase, remove the saturated hydrocarbon collection container and replace it with the aromatic hydrocarbon collection container; S12. GC-MS analysis of saturated hydrocarbons to obtain Pr / Ph values. The GC-MS analysis process is as follows: the initial temperature of the instrument is set to 50°C, the temperature is increased to 120°C at 20°C / min, and then the temperature is increased to 310°C at 3°C / min; the mass spectrometer operates in electron impact mode, the ionization energy is 70 eV, and the scanning range is 50-600 Da; S13, separating the aromatic hydrocarbons to obtain dicyclic aromatic hydrocarbon compounds, and using chromatography-isotope-mass spectrometry to identify and measure the fluorene 13 C isotope, The separation of aromatic hydrocarbons includes the following steps: S131, preparing gradient solvents with a petroleum ether / dichloromethane volume ratio of 9:7, 9:1, 3:1, and 0:100 respectively; S132, fill a clean chromatography column with 1-1.5 g of chromatography silica gel, add 2.5-3 g of Sigma alumina (equal volume to silica gel), wet the chromatography column with an appropriate amount of petroleum ether, and transfer the concentrated aromatic hydrocarbon components in the previous step into the chromatography column; S133. When the sample liquid surface reaches the top interface of the stationary phase, use 6 ml of a mixed solution of petroleum ether / dichloromethane with a volume ratio of 93:7 to wash the single-ring aromatic hydrocarbon compounds 6 times with 1 ml each time. When the last 1 ml of the mixed solution of petroleum ether / dichloromethane with a volume ratio of 93:7 enters the stationary phase, empty the solution in the chromatography column; S134, using 8 ml of a mixed solution of petroleum ether and dichloromethane with a volume ratio of 9:1, wash the dicyclic aromatic hydrocarbons 8 times with 1 ml each time, and when the last 1 ml of the mixed solution of petroleum ether and dichloromethane with a volume ratio of 9:1 enters the stationary phase, empty the solution in the chromatography column; S135, use 8 ml of a mixture of petroleum ether and dichloromethane (volume ratio: 3:1) to wash the tricyclic aromatic hydrocarbons 8 times with 1 ml each time; S14, 13 The C isotope is used as the ordinate and the Pr / Ph value is used as the abscissa to establish 13 The cross plot of C isotope and Pr / Ph value is used to project points on crude oil from different sedimentary environments, divide the regional ranges of different environments, and establish identification charts; S2. Sample processing: S21. Separate the crude oil of the sample to be identified (from the Pearl River Mouth Basin) (this step is the same as S11) to obtain the saturated hydrocarbons and aromatic hydrocarbons of the sample to be identified; S22. Perform gas chromatography - mass spectrometry analysis on the saturated hydrocarbons (this step is the same as S12) to obtain the Pr / Ph value; S23. Separate the aromatic hydrocarbons (this step is the same as S13) to obtain bicyclic aromatic hydrocarbon compounds, and identify and measure the 13 C isotope of fluorene; Sample identification: Plot the Pr / Ph value and the 13 C isotope of fluorene of the crude oil of the sample to be identified onto the discrimination chart for discrimination.

[0040] In this embodiment, the parent material deposition environment, Pr / Ph value, and 13 C isotope of fluorene of the crude oil standard sample are shown in Table 1.

[0041] Table 1 area Parent material deposition environment Pr / Ph <![CDATA[ δ 13 C fluorene (‰)]]> Ordos Basin Coastal swamp phase, source of higher plants 2.17 -23.85 Ordos Basin Coastal swamp phase, source of higher plants 3.62 -23.96 Ordos Basin Coastal swamp phase, source of higher plants 2.89 -24.04 Ordos Basin Coastal swamp phase, source of higher plants 2.01 -23.65 Ordos Basin Coastal swamp phase, source of higher plants 2.23 -23.48 Beibu Gulf Basin River / delta / freshwater lake facies, mixed organic matter sources 4.69 -27.92 Beibu Gulf Basin River / delta / freshwater lake facies, mixed organic matter sources 3.84 -29.74 Beibu Gulf Basin River / delta / freshwater lake facies, mixed organic matter sources 2.62 -33.47 Beibu Gulf Basin River / delta / freshwater lake facies, mixed organic matter sources 2.7 -27.26 Beibu Gulf Basin River / delta / freshwater lake facies, mixed organic matter sources 2.82 -29.52 Beibu Gulf Basin River / delta / freshwater lake facies, mixed organic matter sources 2.66 -27.35 Beibu Gulf Basin River / delta / freshwater lake facies, mixed organic matter sources 2.97 -28.87 Beibu Gulf Basin River / delta / freshwater lake facies, mixed organic matter sources 2.94 -28.09 Tarim Basin Marine, source of lower aquatic organisms 0.83 -32.6 Tarim Basin Marine, source of lower aquatic organisms 0.84 -28.71 Tarim Basin Marine, source of lower aquatic organisms 1.28 -30.85 Tarim Basin Marine, source of lower aquatic organisms 0.86 -29.99 Tarim Basin Marine, source of lower aquatic organisms 0.96 -33.1 Tarim Basin Marine, source of lower aquatic organisms 0.81 -29.92 Tarim Basin Marine, source of lower aquatic organisms 0.88 -28.79 Tarim Basin Marine, source of lower aquatic organisms 1 -31.97 Tarim Basin Marine, source of lower aquatic organisms 0.84 -30.97 Tarim Basin Marine, source of lower aquatic organisms 0.99 -31.52 Termit Basin Transitional phase between land and sea, mainly derived from higher plants 1.02 -22.6 Termit Basin Transitional phase between land and sea, mainly derived from higher plants 1.01 -27.5 Termit Basin Transitional phase between land and sea, mainly derived from higher plants 1.06 -22.6 Termit Basin Transitional phase between land and sea, mainly derived from higher plants 0.83 -26.5 Termit Basin Transitional phase between land and sea, mainly derived from higher plants 0.93 -19.9 Termit Basin Transitional phase between land and sea, mainly derived from higher plants 0.91 -18.9 Termit Basin Transitional phase between land and sea, mainly derived from higher plants 0.93 -22.5 Termit Basin Transitional phase between land and sea, mainly derived from higher plants 1.21 -22.4 Termit Basin Transitional phase between land and sea, mainly derived from higher plants 1.08 -20.4 Termit Basin Transitional phase between land and sea, mainly derived from higher plants 0.88 -21.6 Bongor Basin Saltwater lake phase, algae and bacteria source 1.58 -26.9 Bongor Basin Saltwater lake phase, algae and bacteria source 1.53 -28.5 Bongor Basin Saltwater lake phase, algae and bacteria source 1.54 -28.6 Bongor Basin Saltwater lake phase, algae and bacteria source 1.49 -28.3 Bongor Basin Saltwater lake phase, algae and bacteria source 1.71 -31 Bongor Basin Saltwater lake phase, algae and bacteria source 1.76 -28.7

[0042] The plotting results of the standard sample in step S14 are shown in the appendix Figure 1 . According to Figure 1 , it can be seen that the heavier the 13 C isotope of fluorene, the more it indicates the contribution of terrestrial higher plants, and the higher the Pr / Ph, the more oxidized the deposition environment.

[0043] Establish a discrimination chart based on the plotting results, as shown in the appendix Figure 2 . It is divided into 5 regions in total. Among them, region 1 ( 13 C isotope < -28‰, Pr / Ph < 1.5) indicates that the deposition environment of the crude oil parent material is marine, from lower aquatic organisms; region 2 ( 13 C isotope < -26‰, 1.5 < Pr / Ph ≤ 2) indicates a brackish lake facies, from algae and bacteria; region 3 ( 13 C isotope < -26‰, Pr / Ph > 2) indicates a river / delta / freshwater lake facies, from mixed organic matter; region 4 ( 13 C isotope > -28‰, Pr / Ph ≤ 1.5) indicates a transitional marine - continental facies, mainly from higher plants; region 5 ( 13 C isotope > -26‰, Pr / Ph > 1.5) indicates a shore - marsh facies, from higher plants.

[0044] The Pr / Ph value and the 13 C isotope of fluorene of the crude oil of the sample to be identified are shown in Table 2.

[0045] Table 2 area Pr / Ph <![CDATA[ δ 13 C fluorene (‰)]]> Pearl River Mouth Basin 4.46 -29.04 Pearl River Mouth Basin 4.42 -26.06 Pearl River Mouth Basin 4.59 -27.6 Pearl River Mouth Basin 3.21 -27.54 Pearl River Mouth Basin 3.27 -26.32 The Pr / Ph value and the13 C isotope projection to the identification plate, see attached Figure 3 ,The results show that the crude oil parent material depositional environment is river / delta / freshwater lake phase, with mixed organic matter sources, which is consistent with the actual geological conditions.

[0046] The present invention utilizes fluorene in crude oil 13 C isotope and Pr / Ph value solve the problem of identifying the parent material sedimentary environment of crude oil affected by secondary effects such as maturity and biodegradation. Through the present invention, the parent material sedimentary environment of crude oil can be accurately obtained with high accuracy and universality, providing favorable technical support for oil source comparison, oil and gas filling pathways and oil and gas reservoir research.

[0047] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for identifying the depositional environment of crude oil parent material, It is characterized in that The steps include: Reference material treatment: Crude oils from different sedimentary environments were separated, and the separated products were subjected to chromatography-mass spectrometry and chromatography-isotope-mass spectrometry to obtain the Pr / Ph value and fluorene 13 C isotope, establish identification plate; Sample processing: Separate the crude oil sample to be identified, and perform chromatography-mass spectrometry and chromatography-isotope-mass spectrometry on the separated products to obtain the Pr / Ph value and fluorene 13 C isotope; Sample identification: The Pr / Ph value of the crude oil to be identified and the 13 Project the C isotope onto the identification plate for identification.

2. A method for identifying a crude oil parent material deposition environment according to claim 1, It is characterized in that The control substance treatment comprises the following steps: Crude oils from different sedimentary environments are separated to obtain saturated hydrocarbons and aromatic hydrocarbons of different crude oils; The saturated hydrocarbons were subjected to chromatography-mass spectrometry analysis to obtain the Pr / Ph value; Aromatic hydrocarbons were separated to obtain dicyclic aromatic hydrocarbon compounds, and the fluorene was identified and measured by chromatography-isotope-mass spectrometry. 13 C isotope; Establish 13 The cross plot of C isotope and Pr / Ph value is used to project points on crude oils originating from different sedimentary environments, divide the regional ranges of different environments, and establish an identification map.

3. The method for identifying the deposition environment of crude oil parent material according to claim 1, It is characterized in that The sample processing comprises the following steps: Separating the sample crude oil to be identified to obtain saturated hydrocarbons and aromatic hydrocarbons of the sample to be identified; The saturated hydrocarbons were subjected to chromatography-mass spectrometry analysis to obtain the Pr / Ph value; Aromatic hydrocarbons were separated to obtain dicyclic aromatic hydrocarbon compounds, and the fluorene was identified and measured by chromatography-isotope-mass spectrometry. 13 C isotope.

4. A method for identifying a crude oil parent material deposition environment according to any one of claims 1 to 3, It is characterized in that The crude oil separation comprises the following steps: The crude oil was dissolved in petroleum ether, and after settling, asphaltene and sample concentrate were filtered out; The sample concentrate is separated into saturated hydrocarbons and aromatic hydrocarbons by chromatography.

5. A method for identifying a crude oil parent material deposition environment according to claim 2 or 3, It is characterized in that The aromatic hydrocarbon separation comprises the following steps: respectively preparing gradient mixed solvents with different petroleum ether / dichloromethane volume ratios; Fill the chromatography column with chromatography silica gel, then add alumina in an equal volume to the chromatography silica gel, wet the chromatography column with petroleum ether, and transfer the aromatic hydrocarbons into the chromatography column; When the sample liquid surface reaches the top interface of the stationary phase, the mixed solutions with different petroleum ether / dichloromethane volume ratios are used for flushing in the order of petroleum ether concentration from high to low.

6. A method for identifying a crude oil parent material deposition environment according to claim 5, It is characterized in that The gradient mixed solvents with different petroleum ether / dichloromethane volume ratios include gradient mixed solvents with petroleum ether / dichloromethane volume ratios of 93:7, 9:1, 3:1, and 0:100, respectively.

7. A method for identifying a crude oil parent material deposition environment according to claim 5, It is characterized in that When the sample liquid surface reaches the top interface of the stationary phase, a mixed solution of petroleum ether / dichloromethane with a volume ratio of 93:7 is used to wash the monocyclic aromatic hydrocarbon compound multiple times; When the last mixed solution of petroleum ether / dichloromethane with a volume ratio of 93:7 enters the stationary phase, the solution in the chromatography column is emptied; Use a mixed solution of petroleum ether / dichloromethane with a volume ratio of 9:1 to wash the dicyclic aromatic hydrocarbon compounds multiple times; When the last mixed solution of petroleum ether / dichloromethane with a volume ratio of 9:1 enters the stationary phase, the solution in the chromatography column is emptied; The tricyclic aromatic hydrocarbon compounds were rinsed several times using a mixed solution of petroleum ether / dichloromethane with a volume ratio of 3:

1.

8. A method for identifying a crude oil parent material deposition environment according to claim 2, It is characterized in that The establishment 13 The cross plot of C isotopes and Pr / Ph values ​​is processed as follows: by 13 A cross plot was established with C isotope as the ordinate and Pr / Ph value as the abscissa.

9. A method for identifying a crude oil parent material deposition environment according to claim 2, It is characterized in that The establishment of the recognition plate is processed as follows: Crude oil from different sedimentary environments is projected into the intersection map to divide the regional ranges of different environments.

10. The method for identifying the crude oil parent material deposition environment according to claim 1, It is characterized in that The identification plate includes 5 areas: Area 1 13 C isotope ≤ -28‰, Pr / Ph < 1.5, indicating that the crude oil parent material was deposited in marine environment and originated from lower aquatic organisms; In Region 2 13 The C isotope ≤ -26‰, 1.5 < Pr / Ph ≤ 2, indicating a saline lake facies and being sourced from algae and bacteria; Region 3 13 C isotope ≤ -26‰, Pr / Ph>2, indicating river / delta / freshwater lake phase, which is a mixed organic matter source; Region 4 13 C isotope>-28‰, Pr / Ph≤1.5, indicating a transitional phase between land and sea, and the source of higher plants; Area 5 13 C isotope>-26‰ and Pr / Ph>1.5, indicating a coastal swamp phase, which is the source of higher plants.

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