A method of determining the distance of petroleum migration in the vertical direction

Abstract

This invention provides a method for determining the longitudinal migration distance of petroleum, comprising the following steps: identifying potential source rocks based on parameters such as organic matter abundance, organic matter type, and organic matter maturity; obtaining biomarker compound parameters Po and Ps from extracts of discovered petroleum and potential source rocks in the study area; classifying the discovered petroleum genetically using other parameters to divide it into groups; identifying the corresponding source rocks; and for each set of source rocks, determining its extract maturity parameter P. sm The horizontal axis is used to correct the depth D based on the sampling points. sc P is the ordinate. sm -D sc The relationship diagram yields the curves L showing the variation of maturity parameters with depth. s The formation depth D of the petroleum sample was obtained. og Using oil to generate depth D og With the current burial depth D oa Calculate the longitudinal migration distance D of oil and gas. m equals D oa -D og The principle and steps of this invention are simple, and it can solve the problem of the vertical migration distance of oil. The results can be used to determine the range of oil supply from source rocks in the vertical direction, and guide oil and gas exploration deployment.

Description

Technical Field

[0001] This invention belongs to the field of oil and gas exploration technology, specifically relating to a method for determining the longitudinal migration distance of oil. Background Technology

[0002] Determining the vertical and horizontal migration distances of oil and gas after they are discharged from source rocks, i.e., defining the hydrocarbon supply range of source rocks, is the basis for predicting the spatial distribution of oil and gas, determining the exploration range, and selecting exploration targets. It is also the foundation for evaluating the hydrocarbon supply capacity of source rocks and conducting resource assessment.

[0003] Currently, the prediction of oil and gas migration distances is mainly accomplished through the analysis of transport systems, with little consideration given to the hydrocarbon supply capacity of source rocks and the migration distances of discovered oil and gas. This makes it difficult to objectively evaluate and accurately determine the actual oil and gas supply range of source rocks, limiting its guiding significance for oil and gas exploration scope and target selection. All discovered oil and gas have undergone a certain migration distance. If the migration distances of discovered oil and gas can be determined, the lower limit of the oil supply range of source rocks can be obtained. This can not only directly guide oil and gas distribution prediction and exploration target selection, but also guide source rock evaluation and resource prediction.

[0004] Based on this, a method is proposed that is applicable to areas that have undergone a certain period of exploration and have already discovered oil and gas, for determining the vertical migration distance of oil. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a method for determining the longitudinal migration distance of oil, in order to address the shortcomings of the prior art mentioned above.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a method for determining the longitudinal migration distance of oil, comprising the following steps:

[0007] S101. Based on parameters such as organic matter abundance, organic matter type, and organic matter maturity, potential source rocks are identified.

[0008] S102. Obtain biomarker compound parameters Po and Ps from petroleum and potential source rock extracts discovered in the study area;

[0009] S103. Using the petroleum biomarker compound parameters obtained in S102, and with the help of other parameters, classify the discovered petroleums by their genesis and divide them into groups.

[0010] S104. Using the biomarker compound parameters of petroleum and potential source rock extracts obtained in S102, and with the help of other parameters, determine the source of petroleum in each group by comparing oil sources, and identify the corresponding source rocks.

[0011] S105. For each set of source rocks, its extract maturity parameter P is used. sm The x-axis represents the depth D corrected by the sampling points. sc P is plotted as the ordinate. sm -D sc The relationship diagram yields the curves L showing the variation of maturity parameters with depth. s ;

[0012] S106. Input the parameters obtained in S102 into the P obtained in S105. sm -D sc On the relationship diagram, draw a perpendicular line L through each petroleum sample point. o L o With L s The depth of the intersection point yields the petroleum sample formation depth D. og ;

[0013] S107 utilizes oil to generate depth D og Compared with the current burial depth (D) oa ), calculate the longitudinal migration distance D of oil and gas m equals D oa -D og .

[0014] As a further explanation of the present invention, the corrected depth D of the source rock sampling point is obtained in S105. sc The method, namely:

[0015] D sc = D s + H d

[0016] Where D sc The burial depth after correction of the sampling points;

[0017] D s This represents the current burial depth of the sampling point;

[0018] H d The erosion thickness of the source rock itself and the overlying strata is determined using existing stratigraphic erosion calculations, or through stratigraphic trend surface tracing methods, R... o This is obtained using the AC trend compensation method;

[0019] H when the source rock and overlying strata have not been eroded d =0.

[0020] As a further illustration of the present invention, using D m The method for determining the characteristics of oil migration is as follows:

[0021] D m A value greater than 0 indicates that oil is migrating upwards and forming reservoirs.

[0022] D m <0 indicates that oil flows downwards and migrates to form reservoirs;

[0023] D m = 0 indicates that oil accumulates in place.

[0024] Compared with the prior art, the present invention has the following advantages:

[0025] The principle and steps of this invention are simple. It can determine the vertical migration distance of oil. Moreover, based on the calculation results, it can not only determine the vertical distance of source rocks to supply oil and predict the distribution range of oil and gas, but also be used for source rock and resource evaluation, and guide oil and gas exploration deployment. It is convenient and practical. Attached Figure Description

[0026] Figure 1 This is a flowchart of the overall method of the present invention;

[0027] Figure 2 This is a diagram showing the determination of the longitudinal migration distance of oil in the Es group of the WJG region in the experimental example of this invention. Detailed Implementation

[0028] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] Examples, such as Figure 1 As shown, the present invention provides a technical solution: a method for determining the longitudinal migration distance of oil, comprising the following steps:

[0030] S101. Based on parameters such as organic matter abundance, organic matter type, and organic matter maturity, potential source rocks are identified.

[0031] An oil and gas basin often develops multiple hydrocarbon-generating depressions and multiple sets of source rocks. Identifying potential source rocks is the basis for determining the source of oil and calculating the vertical migration distance of oil.

[0032] The identification of potential source rocks requires consideration of three parameters: organic matter abundance, organic matter type, and organic matter maturity. This can be achieved by collecting existing data on organic matter abundance, organic matter type, and organic matter maturity in the study area, or by sampling and analyzing these parameters, and then making a judgment based on the relevant petroleum industry standards.

[0033] Generally, TOC ≥ 0.5%, Ro ≥ 0.5%, and organic matter type I-II2 can be used as criteria for judging potential source rocks for petroleum.

[0034] S102. Obtain biomarker compound parameters Po and Ps from petroleum and potential source rock extracts discovered in the study area;

[0035] These parameters can be obtained using the following methods:

[0036] 1) By collecting existing chromatographic-mass spectrometry analysis data of petroleum and source rock extracts, calculate the biomarker parameters Po of discovered petroleum and Ps of source rock extracts. These parameters include, but are not limited to, maturity parameters.

[0037] 2) The system collects samples of discovered petroleum and potential source rocks, and performs petroleum processing, group component separation and chromatographic-mass spectrometry analysis of saturated hydrocarbons and aromatics, and calculation of biomarker parameters. It also performs extraction of soluble organic matter from source rocks, group component separation and chromatographic-mass spectrometry analysis of saturated hydrocarbons and aromatics, and calculation of biomarker parameters. The calculated parameters include, but are not limited to, maturity parameters.

[0038] 3) Existing data collection and analysis should be conducted simultaneously with the collection and testing of new samples. When collecting new petroleum and source rock samples, the quantity and distribution of existing data should be analyzed to enrich and supplement the existing data.

[0039] S103. Using the petroleum biomarker compound parameters obtained in S102, and with the help of other parameters, classify the discovered petroleums by their genesis and divide them into groups.

[0040] Petroleum groups can be identified using cluster analysis methods. Other parameters that can be used include crude oil properties and stable carbon isotope composition.

[0041] An oil and gas basin may contain only one oil group, or it may contain multiple oil groups, such as A, B, C, etc.

[0042] S104. Using the biomarker compound parameters of petroleum and potential source rock extracts obtained in S102, and with the help of crude oil properties and stable carbon isotope composition, the source of petroleum in each group is determined by oil source comparison, and the corresponding source rock is identified.

[0043] Specifically, based on the principle of "correlation and similarity," oil source comparison work is carried out to identify the source rocks for oil from various groups of potential source rocks, which are called effective source rocks.

[0044] Oil source correlation can be accomplished through fingerprint comparison, i.e., comparison of chromatographic and mass spectra of petroleum and source rock extracts, and parameter comparison, including comparison of two-parameter scatter plots, three-parameter triangular plots, and multi-parameter star plots.

[0045] S105. For each set of source rocks, its extract maturity parameter P is used. sm The x-axis represents the depth D corrected by the sampling points. sc P is plotted as the ordinate. sm -D sc The relationship diagram yields the curves L showing the variation of maturity parameters with depth. s ;

[0046] Obtain the corrected depth D of the source rock sampling point sc The method, namely:

[0047] D sc = D s + H d

[0048] Where D sc The burial depth after correction of the sampling points;

[0049] D s This represents the current burial depth of the sampling point;

[0050] H d The erosion thickness of the source rock itself and the overlying strata is determined using existing stratigraphic erosion calculations, or through stratigraphic trend surface tracing methods, R... o This is obtained using the AC trend compensation method;

[0051] H when the source rock and overlying strata have not been eroded d =0.

[0052] S106. Input the parameters obtained in S102 into the P obtained in S105. sm -D sc On the relationship diagram, draw a perpendicular line L through each petroleum sample point. o L o With L s The depth of the intersection point yields the petroleum sample formation depth D. og ;

[0053] S107 utilizes oil to generate depth D og Compared with the current burial depth (D) oa ), calculate the longitudinal migration distance D of oil and gas m equals D oa -D og .

[0054] Using D m The method for determining the characteristics of oil migration is as follows:

[0055] D m A value greater than 0 indicates that oil is migrating upwards and forming reservoirs.

[0056] D m <0 indicates that oil flows downwards and migrates to form reservoirs;

[0057] D m = 0 indicates that oil accumulates in place.

[0058] Experimental examples, such as Figure 2 As shown;

[0059] The WJG area is located on the southeastern slope of the D depression in eastern my country. Multiple types of oil have been discovered in several reservoir systems. The D depression has three source rocks, Es3, Es4, and Ek, all of which have the capacity to supply oil to the WJG area.

[0060] S101. Identification of Potential Source Rocks: Oil and gas in the WJG area originate from the DY Depression, with three sets of source rocks: Es3, Es4, and Ek. Based on existing parameters of organic matter abundance, organic matter type, and organic matter maturity, all three sets of source rocks meet the standards of TOC≥0.5%, Ro≥0.5%, and organic matter type I-II2. Furthermore, it has been proven that hydrocarbon generation and expulsion processes have occurred, and all three sets of source rocks are potential source rocks for petroleum already discovered in the WJG area.

[0061] S102. Obtain biomarker compound parameters of discovered petroleum and potential source rock extracts: In this embodiment, 73 sets of chromatographic-mass spectrometry analysis data of petroleum and source rock extracts were collected and organized, including 31 sets of petroleum data and 42 sets of source rock data from three sets; more than 300 sets of biomarker compound parameters were calculated, including parameters such as maturity, source of parent material, and sedimentary environment.

[0062] S103. Classification of discovered oil groups: Using the petroleum biomarker compound parameters calculated in S101, and referring to the physical properties of crude oil such as density, viscosity, and sulfur content, the crude oil in the WJG area is classified into three groups: A, B, and C.

[0063] S104. Source correlation to determine the origin of each oil group: Using the biomarker compound parameters of oil and potential source rock extracts obtained in S101, the source of crude oil in each group was clarified through fingerprint comparison and parameter comparison. The results showed that group A came from Es4 source rock, group B came from Ek source rock, and group C came from a mixture of Es4 and Ek source rocks. No crude oil from Es3 source rock was found.

[0064] The following uses group A (oil) as an example to illustrate the process of determining the longitudinal migration distance of oil. The methods and steps for determining groups B and C are the same.

[0065] S105. Plot the curves of maturity parameters of source rock Es4 (source rock of petroleum group A) as a function of depth. s : Based on the maturity parameter P of its extract sm The x-axis represents the depth D corrected by the sampling points. sc P is plotted as the ordinate. sm -D sc Relationship diagram.

[0066] Here P sm C29 was selected. 甾烷 αααS / (S+R) can be used in practice, but other maturity parameters, such as C31, can also be selected. 藿烷 22S / (S+R), Ph / nC18, etc.; After the deposition of Es4 source rocks, the erosion of the overlying strata can be ignored, therefore D sc That is, the sample depth D s .

[0067] Es4 source rock C29 甾烷 αααS / (S+R)- D s Relationship diagram as follows Figure 2 As shown in the figure, the dotted dashed line represents C31. 藿烷 The curve of 22S / (S+R) as a function of depth L s .

[0068] S106. Determine the depth D where oil has been discovered. og The maturity parameter C29 of population A obtained from S102. 甾烷 αααS / (S+R) is thrown to Figure 2 Above, draw a perpendicular line L through each petroleum sample point. o L o With L s The depth of the intersection point is the formation depth D of the petroleum sample. og .

[0069] This experimental example only uses A1 and A2 petroleum as examples to draw the perpendicular line L. o1 L o2 , respectively with L s Intersecting at a1 and a2, corresponding to depth D og1 D og2 This refers to the depth at which A1 and A2 oils are formed.

[0070] S107. Using the difference between the oil formation depth (Dog) and the current burial depth (Doa), the longitudinal migration distance Dm of each oil sample is calculated to be equal to Doa - Dog.

[0071] According to the calculation results, the longitudinal migration distances of A1 and A2 oil are 1582m and 1375m, respectively.

[0072] Extracted from petroleum group A and source rock C29 甾烷 The distribution of αααS / (S+R) indicates that the oil and gas generated from the Es4 source rock all migrated upwards to form reservoirs.

[0073] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0074] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for determining the longitudinal migration distance of oil, characterized in that: Includes the following steps: S101. Based on parameters such as organic matter abundance, organic matter type, and organic matter maturity, potential source rocks are identified. S102. Obtain biomarker compound parameters Po and Ps from petroleum and potential source rock extracts discovered in the study area; S103. Using the petroleum biomarker compound parameters obtained in S102, and with the help of crude oil properties and stable carbon isotope composition, the discovered petroleum is genetically classified and divided into groups. S104. Using the biomarker compound parameters of petroleum and potential source rock extracts obtained in S102, and with the help of crude oil properties and stable carbon isotope composition, the source of petroleum in each group is determined by oil source comparison, and the corresponding source rock is identified. S105. For each set of source rocks, its extract maturity parameter P is used. sm The x-axis represents the depth D corrected by the sampling points. sc P is plotted as the ordinate. sm -D sc The relationship diagram yields the curves L showing the variation of maturity parameters with depth. s ; S106. Input the parameters obtained in S102 into the P obtained in S105. sm -D sc On the relationship diagram, draw a perpendicular line L through each petroleum sample point. o L o With L s The depth of the intersection point yields the petroleum sample formation depth D. og ; S107, Utilizing oil to generate depth D og With the current burial depth D oa Calculate the longitudinal migration distance D of oil and gas. m equals D oa -D og .

2. The method for determining the longitudinal migration distance of oil according to claim 1, characterized in that, The corrected depth D of the source rock sampling point was obtained in S105. sc The method, namely: D sc = D s + H d Where D sc The burial depth after correction of the sampling points; D s This represents the current burial depth of the sampling point; H d The erosion thickness of the source rock itself and the overlying strata is determined using existing stratigraphic erosion calculations, or through stratigraphic trend surface tracing methods, R... o This is obtained using the AC trend compensation method; H when the source rock and overlying strata have not been eroded d =0.

3. The method for determining the longitudinal migration distance of oil according to claim 1, characterized in that, Using D m The method for determining the characteristics of oil migration is as follows: D m > 0 indicates that oil has migrated upwards and formed reservoirs; D m < 0 indicates that oil is flowing downwards and migrating to form reservoirs; D m = 0 indicates that oil accumulates in place.

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