Method and device for identifying origin of crude oil

Abstract

The invention discloses a method and a device for identifying causes and sources of crude oil, and relates to the technical field of oil and gas reservoir exploration, the key points of the technical scheme are as follows: on the basis of oil samples of different sedimentary facies in a whole oil chromatography experiment and a saturated hydrocarbon and aromatic hydrocarbon chromatography-mass spectrometry experiment, representative geochemical parameter indexes of sedimentary facies, biogenesis and maturity are respectively determined; in combination with a whole-oil carbon isotope experiment, typical geochemical parameter indexes which are highly related to the whole-oil carbon isotopes are determined, and finally quantitative indexes for identifying crude oil of different sedimentary facies are constructed by integrating the whole-oil carbon isotopes and the typical geochemical parameter indexes. The method for quickly and efficiently identifying the oil and gas cause source of the multiphase source oil and gas reservoir is established, so that the cause source of complex source oil in different regions can be quickly and efficiently identified through a geochemical method and means; the method has important significance in the aspects of evaluating the oil and gas resource potential of a research area and further exploration deployment work by an oil and gas exploration and production unit.

Description

Technical Field

[0001] The present invention relates to the technical field of oil and gas reservoir exploration, and more specifically, it relates to a method and device for identifying the genetic origin of crude oil. Background Art

[0002] Global oil and gas resources are mainly in marine strata and mainly come from marine sapropelic source rocks; while the sources of oil and gas resources in China are relatively rich, including not only marine sapropelic source rocks, but also a large number of continental source rocks, mainly including continental lacustrine sapropelic source rocks and coal measure source rocks. With the continuous deepening of oil and gas exploration, the difficulty of oil and gas exploration is increasing. In many basins in China, including the Tarim Basin and the Sichuan Basin, there are oil and gas with multiple sources, and the resource potential is large. Therefore, strengthening the exploration and development of oil and gas with complex sources is of great significance for optimizing China's energy structure, building a clean, low-carbon, safe and efficient energy system, and protecting the ecological environment.

[0003] Identifying the genetic origin of crude oil with complex sources has always been a relatively complex problem. At present, the difficulty and risk of new discoveries in oil and gas exploration are both increasing. The discovery of gas reservoirs with conventional single genetic origin is decreasing, and various complex oil and gas reservoirs with high evolution and multiple sources are increasing. The genetic origin of complex crude oil is diverse. On the one hand, it is controlled by different sedimentary environments, parent material sources, and maturities. Relying solely on a single geochemical index can no longer meet the need to identify the genetic origin of complex-source oil, which restricts the progress of the next exploration deployment work and the optimization of favorable zones by oil and gas exploration experts. On the other hand, since crude oils in different regions have different characteristics, it is necessary to establish a systematic geochemical comprehensive research method, propose relevant geochemical indexes, and establish a quantitative index system for identifying the genetic origin of complex-source crude oil, so that oil and gas exploration and development production units can quickly and efficiently identify the genetic origin of complex-source oil in different regions through geochemical methods and means. This is of great significance for evaluating the oil and gas resource potential of the study area and further exploration deployment work.

[0004] For the above reasons, the present invention provides a method and device for quickly and efficiently identifying the genetic origin of crude oil in complex multi-source oil and gas reservoirs. Summary of the Invention

[0005] To achieve the above object, the present invention provides the following technical solution: A method for identifying the genetic origin of crude oil, which includes the following steps:

[0006] S1. Collect oil samples from different sedimentary facies in the target area.

[0007] S2. Conduct oil and gas geochemical test analysis on the oil samples collected in S1. The oil and gas geochemical test analysis includes whole oil chromatographic experimental analysis, saturated hydrocarbon and aromatic hydrocarbon chromatographic - mass spectrometric experimental analysis, and whole oil carbon isotope experimental analysis.

[0008] S3. Based on the results of the whole oil chromatographic experimental analysis and the results of the saturated hydrocarbon and aromatic hydrocarbon chromatographic - mass spectrometric experimental analysis, respectively determine the representative geochemical parameter indicators related to sedimentary facies, biological source, and maturity.

[0009] S4. Based on the results of the oil and gas geochemical test analysis, respectively conduct correlation analysis between each representative geochemical parameter indicator and the whole oil carbon isotope, and determine one or more representative geochemical parameter indicators that are correlated with the whole oil carbon isotope as typical geochemical parameter indicators.

[0010] S5. Based on the results of the oil and gas geochemical test analysis, according to the whole oil carbon isotope and all typical geochemical parameter indicators, determine the quantitative indicators for identifying different sedimentary facies, and construct a geochemical parameter identification system for identifying the sources of oil samples with different sedimentary facies.

[0011] S6. Collect oil samples outside the target area, conduct the oil and gas geochemical test analysis in S2 on the oil samples outside the target area, and based on the analysis results, combined with the identification system constructed in S5, identify the sedimentary facies source of the crude oil outside the target area.

[0012] The present invention is further set as: The representative geochemical parameter indicators of the sedimentary facies are the ratio of n - propylbenzene to benzene Pr / Ph and the ratio of benzene to n - octadecane and n - heptadecane Ph / nC 18 -Pr / nC 17 , which are obtained based on the results of the whole oil chromatographic experimental analysis or the results of the saturated hydrocarbon and aromatic hydrocarbon chromatographic - mass spectrometric experimental analysis.

[0013] The present invention is further set as: Construct a correlation diagram of Pr / Ph and Ph / nC 18 -Pr / nC 17 to show the differences in oil samples of different sedimentary facies.

[0014] The present invention is further set as: The representative geochemical parameter indicators of the biological source are the tricyclic terpane parameters C19 + C20TT, C21TT, and C23TT in the oil sample, which are obtained based on the results of the saturated hydrocarbon and aromatic hydrocarbon chromatographic - mass spectrometric experimental analysis.

[0015] The present invention is further set as: If C19 + C20TT in the oil sample is the highest, it indicates that the main biological source of the oil sample is higher terrestrial plants; if C21TT is the highest, it indicates that the main biological source of the oil sample is lower aquatic organisms in freshwater lakes; if C23TT is the highest, it indicates that the main biological source of the oil sample is lower aquatic organisms in marine or saline lake facies.

[0016] The present invention is further configured to: respectively take C19+C20TT, C21TT, and C23TT as vertices to construct a triangular diagram for representing C19+C20TT, C21TT, and C23TTT in the oil sample, so as to indicate the sources of different oil samples.

[0017] The present invention is further configured to: the representative geochemical parameter indexes for maturity are the methylphenanthrene parameter MPI-1 and the methyldibenzothiophene parameter MDR, which are obtained based on the results of whole-oil chromatographic experimental analysis or the results of saturated hydrocarbon and aromatic hydrocarbon chromatographic-mass spectrometric experimental analysis. The larger the MPI-1 and MDR, the higher the maturity of the oil sample.

[0018] The present invention is further configured to: construct a correlation diagram of MPI-1 and MDR to indicate the differences in the maturity of different oil samples.

[0019] The present invention is further configured to: the sedimentary facies include marine facies, lacustrine facies, and swamp facies.

[0020] The present invention is further configured to: the typical geochemical parameter indexes are Pr / Ph and the tricyclic terpane parameters C19+C20TT, C21TT, and C23TT. Pr / Ph is obtained based on the results of whole-oil chromatographic experimental analysis or the results of saturated hydrocarbon and aromatic hydrocarbon chromatographic-mass spectrometric experimental analysis. The tricyclic terpane parameters C19+C20TT, C21TT, and C23TT are obtained based on the results of saturated hydrocarbon and aromatic hydrocarbon chromatographic-mass spectrometric experimental analysis.

[0021] The present invention is further configured to: the whole-oil carbon isotope is -33 to -31‰, Pr / Ph < 1.5, and the tricyclic terpane parameters are C19+C20TT < 50%, C23TT > 25%, C21TT ≤ 35%, representing oil from a typical marine source.

[0022] The present invention is further configured to: the whole-oil carbon isotope is -29 to -27‰, Pr / Ph is 1.5 to 2.5, and the tricyclic terpane parameters are C19+C20TT < 50%, C23TT < 25%, C21TT > 25%, representing oil from a typical lacustrine source.

[0023] The present invention is further configured to: the whole-oil carbon isotope is -26 to -24‰, Pr / Ph > 2.5, and the tricyclic terpane parameters are C19+C20TT > 50%, C23TT < 25%, C21TT < 25%, representing oil from a swamp source.

[0024] The present invention is further configured to: respectively construct a correlation diagram of each representative geochemical parameter index and the whole-oil carbon isotope of the oil sample to analyze the correlation between different representative geochemical parameter indexes and the whole-oil carbon isotope.

[0025] The present invention also provides a device for identifying the genetic origin of crude oil, which includes a storage medium and a processor, and a computer program is stored on the storage medium. The processor is used to implement the method for identifying the genetic origin of crude oil as described above when executing the computer program.

[0026] In summary, the present invention has the following beneficial effects compared with the prior art: Based on the whole-oil chromatographic experimental analysis, saturated hydrocarbon and aromatic hydrocarbon chromatographic-mass spectrometric experimental analysis of oil samples in different sedimentary facies, representative geochemical parameter indexes related to sedimentary facies, biological sources and maturity are respectively determined. Combining with the whole-oil carbon isotope experimental analysis, typical geochemical parameter indexes with relatively large correlation with the whole-oil carbon isotope in the representative geochemical parameter indexes are determined. Finally, a quantitative index for identifying crude oil in different sedimentary facies is constructed by integrating the whole-oil carbon isotope and the typical geochemical parameter indexes, and a method for quickly and efficiently identifying the genetic origin of oil and gas in a multi-phase source oil and gas reservoir is established, enabling oil and gas exploration and development production units to quickly and efficiently identify the genetic origin of complex-source oils in different regions through geochemical methods and means. This is of great significance for oil and gas exploration and production units in evaluating the oil and gas resource potential of the study area and further exploration deployment work. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a flow schematic diagram of the method for identifying the genetic origin of crude oil.

[0028] Figure 2 It is the Pr / Ph and Ph / nC 18 -Pr / nC 17 correlation diagram of oil samples in different sedimentary facies;

[0029] Figure 3 It is a triangular diagram of tricyclic terpane parameters of oil samples in different sedimentary facies;

[0030] Figure 4 It is a correlation diagram of MPI-1 and MDR of oil samples in different sedimentary facies;

[0031] Figure 5 It is a correlation diagram of the whole-oil carbon isotope δ13Coil‰ and MPI-1 of oil samples in different sedimentary facies;

[0032] Figure 6 It is a correlation diagram of the whole-oil carbon isotope δ13Coil‰ and MDR of oil samples in different sedimentary facies;

[0033] Figure 7 It is a correlation diagram of the whole-oil carbon isotope δ13Coil‰ and Pr / Ph of oil samples in different sedimentary facies. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0034] The technical solution of the present invention will be clearly described below in conjunction with the accompanying drawings. Obviously, the described embodiments are not all embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the invention.

[0035] Embodiment

[0036] As Figure 1 shown, in a preferred embodiment of the present invention, it is a schematic flow chart of a method for identifying the origin of crude oil, which includes the following steps:

[0037] S1. Collect oil samples of different sedimentary facies in the target area. The sedimentary facies include marine facies, lacustrine facies and swamp facies.

[0038] S2. Conduct oil and gas geochemical test analysis on the oil samples collected in S1. The oil and gas geochemical test analysis includes whole oil chromatographic experimental analysis, saturated hydrocarbon and aromatic hydrocarbon chromatogram-mass spectrometry experimental analysis, and whole oil carbon isotope experimental analysis.

[0039] S3. Based on the results of the whole oil chromatographic experimental analysis and the results of the saturated hydrocarbon and aromatic hydrocarbon chromatogram-mass spectrometry experimental analysis, respectively determine the representative geochemical parameter indexes related to sedimentary facies, source and maturity.

[0040] Based on the relevant indexes of n-alkanes and isoprenoids obtained from the whole oil chromatographic experimental analysis, isoprenoid alkanes in crude oil are an important parameter reflecting the organic facies characteristics of source rocks. As Figure 2 shown, according to the Pr / Ph and Ph / nC 18 -Pr / nC 17 correlation diagram, it can show the significant differences in oil samples from marine facies, lacustrine facies and swamp facies.

[0041] The biomarker tricyclic terpane can effectively identify different source matrices. C19+C20T is mainly from terrestrial higher plants, C21TT is mainly from lower aquatic organisms in fresh water lakes, and C23TT is mainly from lower aquatic organisms in marine or saline lake facies. As Figure 3 is a triangular diagram of C19+C20TT - C21TT - C23TT, which represents the source matrix characteristics of oils from different sources. Among them, area A represents crude oil from typical lacustrine facies with more C21TT content, area B represents crude oil from typical marine facies mainly with C23TT, and area C represents crude oil from typical coal measures mainly with C19+C20TT.

[0042] Aromatic hydrocarbon parameter indexes, such as the methylphenanthrene parameter MPI1 (MPI1 = 1.5*(3-MP + 2-MP) / (P + 9-MP + 1-MP)) and the methyldibenzothiophene parameter MDR (MDR = 4- / 1-MDBT), can be used to effectively identify the maturity of oil samples in the study area. AsFigure 4 As shown, there are significant differences in the maturity of crude oils from different sources. The maturity of the crude oils in the Luntai area is the highest, followed by that of the marine-source crude oils in the Yakela area, and the maturity of the lacustrine source rocks in the Dalaoba area is the lowest.

[0043] S4. Based on the results of oil and gas geochemical test analysis, correlation analysis is respectively carried out between each representative geochemical parameter index and the whole-oil carbon isotope to analyze the main controlling factors of the differences in the origin of oil and gas, and one or more representative geochemical parameter indexes that are correlated with the whole-oil carbon isotope are determined as typical geochemical parameter indexes.

[0044] Specifically, correlation diagrams of each representative geochemical parameter index and the whole-oil carbon isotope of the oil samples are respectively constructed to analyze the correlation between different representative geochemical parameter indexes and the whole-oil carbon isotope. As Figures 5-7 shown, the carbon isotope of petroleum hydrocarbons inherits the composition of its parent organic matter and is also affected by the maturity. For the typical biomarker parameter Pr / Ph and the maturity parameters MPI1 and MDR, correlation analysis with the whole-oil carbon isotope shows that the whole-oil carbon isotope has a good correlation with the biomarker and a poor correlation with the maturity. Therefore, the main controlling factor for the origin of oil and gas is mainly the difference in the source of the hydrocarbon-generating parent material, and the whole-oil carbon isotope can effectively distinguish the differences in the origin of crude oils from different sources.

[0045] Therefore, the typical geochemical parameter indexes in this embodiment are determined as Pr / Ph and the tricyclic terpane parameters C19+C20TT, C21TT, and C23TT. Finally, a quantitative index for identifying marine, lacustrine, and swamp-phase crude oils is established by comprehensively considering the whole-oil carbon isotope, Pr / Ph, and the tricyclic terpane parameters: the whole-oil carbon isotope is -33‰ to -31‰, Pr / Ph < 1.5, and the tricyclic terpane parameters belong to area B of the triangular diagram, that is, C19+C20TT < 50%, C23TT > 25%, C21TT ≤ 35%, representing typical marine-source oils. The whole-oil carbon isotope is -26‰ to -24‰, Pr / Ph > 2.5, and the tricyclic terpane parameters belong to area A of the triangular diagram, that is, C19+C20TT > 50%, C23TT < 25%, C21TT < 25%, representing crude oils from swamp-phase sources. The whole-oil carbon isotope is -29‰ to -27‰, Pr / Ph is 1.5 to 2.5, and the tricyclic terpane parameters belong to area C of the triangular diagram, that is, C19+C20TT < 50%, C23TT < 25%, C21TT > 25%, representing typical lacustrine-source oils.

[0046] S5. Based on the results of oil and gas geochemical test analysis, according to the whole-oil carbon isotope and all typical geochemical parameter indexes, a quantitative index for identifying different sedimentary facies is determined, and a geochemical parameter identification system for identifying oil samples from different sedimentary facies sources is constructed.

[0047] S6. Collect oil samples outside the target area, conduct oil and gas geochemical test analysis on the oil samples outside the target area as in S2, and based on the analysis results, combined with the identification system constructed in S5, effectively identify the origin of the crude oil sedimentary facies outside the target area.

[0048] This embodiment also provides a device for identifying the origin of crude oil, which includes a storage medium and a processor, and a computer program is stored on the storage medium. The processor is configured to implement the above method for identifying the origin of crude oil when executing the computer program.

[0049] In summary, the present invention proposes a method for quickly and efficiently identifying the origin of oil and gas in a multi-phase source oil and gas reservoir, proposes relevant geochemical indicators and establishes a quantitative index system for identifying the origin of crude oil with complex sources, enabling oil and gas exploration and development production units to quickly and efficiently identify the origin of crude oil with complex sources in different regions through geochemical methods and means. This is of great significance for oil and gas exploration and production units in evaluating the oil and gas resource potential of the study area and further exploration deployment work.

[0050] The foregoing is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for identifying the genetic source of crude oil, characterized in that: It includes the following steps: S1. Collect oil samples of different sedimentary facies in the target area; S2. Conduct oil and gas geochemical test analysis on the oil samples collected in S1. The oil and gas geochemical test analysis includes whole oil chromatography experiment analysis, saturated hydrocarbon and aromatic hydrocarbon chromatography-mass spectrometry experiment analysis, and whole oil carbon isotope experiment analysis; S3. Based on the results of the whole oil chromatography experiment analysis and the results of the saturated hydrocarbon and aromatic hydrocarbon chromatography-mass spectrometry experiment analysis, respectively determine the representative geochemical parameter indexes related to sedimentary facies, biological sources, and maturity; S4. Based on the results of the oil and gas geochemical test analysis, respectively conduct correlation analysis between each representative geochemical parameter index and the whole oil carbon isotope, and determine one or more representative geochemical parameter indexes that are correlated with the whole oil carbon isotope as typical geochemical parameter indexes; S5. Based on the results of the oil and gas geochemical test analysis, according to the whole oil carbon isotope and all typical geochemical parameter indexes, determine the quantitative indexes for identifying different sedimentary facies, and construct a geochemical parameter identification system for identifying the sources of oil samples of different sedimentary facies; S6. Collect oil samples outside the target area, conduct the oil and gas geochemical test analysis in S2 on the oil samples outside the target area, and based on the analysis results, combined with the identification system constructed in S5, identify the sedimentary facies sources of the crude oil outside the target area.

2. The method for identifying the origin of crude oil according to claim 1, wherein: The representative geochemical parameter indexes of sedimentary facies are the ratio of n-propylbenzene to phenyl Pr / Ph and the ratio of phenyl to n-octadecane and n-heptadecane Ph / nC 18 -Pr / nC 17 , which are obtained based on the experimental analysis results of whole oil chromatography or the experimental analysis results of saturated hydrocarbon and aromatic hydrocarbon chromatography-mass spectrometry.

3. The method for identifying the origin of crude oil according to claim 2, wherein: Construct the correlation diagrams of Pr / Ph and Ph / nC 18 - Pr / nC 17 to show the differences in oil samples of different sedimentary facies.

4. A method for identifying the origin of crude oil according to claim 1, characterized in that: The representative geochemical parameter indexes of the biological source are the tricyclic terpane parameters C19+C20TT, C21TT, and C23TT in the oil sample, which are obtained based on the results of the saturated hydrocarbon and aromatic hydrocarbon chromatography-mass spectrometry experiment analysis.

5. A method for identifying the origin of crude oil according to claim 4, characterized in that: The highest C19+C20TT in the oil sample indicates that the main biological source of the oil sample is higher plants in the continental facies. The highest C21TT indicates that the main biological source of the oil sample is lower aquatic organisms in fresh water lakes. The highest C23TT indicates that the main biological source of the oil sample is lower aquatic organisms in the marine facies or saline lake facies.

6. A method for identifying the origin of crude oil according to claim 4, characterized in that: Construct a triangular diagram with C19+C20TT, C21TT, and C23TT as vertices respectively to represent C19+C20TT, C21TT, and C23TTT in the oil sample, so as to show different biological sources of the oil sample.

7. A method for identifying the origin of crude oil according to claim 1, characterized in that: The representative geochemical parameter indexes of maturity are the methylphenanthrene parameter MPI-1 and the methyldibenzothiophene parameter MDR, which are obtained based on the results of the whole oil chromatography experiment analysis or the results of the saturated hydrocarbon and aromatic hydrocarbon chromatography-mass spectrometry experiment analysis; the larger MPI-1 and MDR are, the higher the maturity of the oil sample.

8. A method for identifying the origin of crude oil according to claim 7, characterized in that: Construct a correlation diagram of MPI-1 and MDR to show the differences in the maturity of different oil samples.

9. A method for identifying the origin of crude oil according to claim 1, characterized in that: The sedimentary facies include marine facies, lake facies, and swamp facies.

10. A method for identifying the origin of crude oil according to claim 9, characterized in that: The typical geochemical parameter indexes are Pr / Ph and the tricyclic terpane parameters C19+C20TT, C21TT, and C23TT; Pr / Ph is obtained based on the results of the whole oil chromatography experiment analysis or the results of the saturated hydrocarbon and aromatic hydrocarbon chromatography-mass spectrometry experiment analysis; the tricyclic terpane parameters C19+C20TT, C21TT, and C23TT are obtained based on the results of the saturated hydrocarbon and aromatic hydrocarbon chromatography-mass spectrometry experiment analysis.

11. A method for identifying the origin of crude oil according to claim 10, characterized in that: The whole oil carbon isotope is -33‰ to -31‰, Pr / Ph < 1.5, and the tricyclic terpane parameters are C19+C20TT < 50%, C23TT > 25%, and C21TT ≤ 35%, representing oil from typical marine sources.

12. A method for identifying the origin of crude oil according to claim 10, characterized in that: The whole-oil carbon isotope ranges from -29‰ to -27‰, Pr / Ph ranges from 1.5 to 2.5, and the tricyclic terpane parameters are C19+C20TT < 50%, C23TT < 25%, and C21TT > 25%, representing typical lacustrine-source oil.

13. A method for identifying the origin of crude oil according to claim 10, characterized in that: The whole-oil carbon isotope ranges from -26‰ to -24‰, Pr / Ph > 2.5, and the tricyclic terpane parameters are C19+C20TT > 50%, C23TT < 25%, and C21TT < 25%, representing swamp-source oil.

14. A method for identifying the origin of crude oil according to claim 1, characterized in that: Correlation diagrams of each representative geochemical parameter index and the whole-oil carbon isotope of the oil samples are constructed respectively to analyze the correlation between different representative geochemical parameter indexes and the whole-oil carbon isotope.

15. An apparatus for identifying the genetic source of crude oil, characterized in that: It includes a storage medium and a processor, and a computer program is stored on the storage medium; the processor is used to implement the method for identifying the origin of crude oil as described in any one of claims 1 or 9-13 when executing the computer program.

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