Method and system for analyzing secondary migration mode of petroleum

Abstract

The invention discloses a method and a system for analyzing a petroleum secondary migration mode. Comprising the following steps: carrying out an indoor physical experiment on to-be-evaluated petroleum to obtain a capillary number index for representing a competitive characteristic between capillary pressure and viscous force and a Bo number index for representing a competitive characteristic between buoyancy and capillary pressure in a secondary migration process of the to-be-evaluated petroleum; according to the ratio of the capillary number index to the Bo number index, determining the main power type of the to-be-evaluated petroleum by using a preset displacement pressure and buoyancy control migration mode identification chart; and determining the fluid secondary migration mode of the to-be-evaluated petroleum according to the main power type. According to the invention, the petroleum secondary migration law under different geological conditions can be analyzed.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of oil exploration and development, and particularly relates to a method and system for analyzing a secondary migration mode of oil. BACKGROUND

[0002] The secondary migration process of oil is essentially a flow process of fluid (oil) in a complex medium. There are three types of methods for describing the secondary migration process of oil. The first type is to analyze the secondary migration of oil by using the percolation theory of multiple flow. This method can describe the flow process of oil, gas and water by using the equation of multiple flow and the Darcy law under the condition of multiple phases. In order to describe the effect of reservoir heterogeneity, the size of the permeability is introduced into the Darcy percolation equation, and the equation is analyzed by mathematical method, so that the description of this method can consider the control effect of lithology on the secondary migration process of oil. The second type is to describe the secondary migration process of oil by using the fluid potential method. England et al. further considered the effect of capillary force on the basis of the Hubbert fluid potential concept, and defined the fluid potential as the work done for transporting a unit volume of fluid from the reference surface to a point in the underground. Therefore, the new fluid potential has the possibility to describe the secondary migration under the condition of reservoir heterogeneity. The third type is to describe the two-phase flow process in the porous medium by using the percolation theory, and then describe the migration process of oil in the saturated water rock cutoff.

[0003] However, the existing technologies cannot adaptively optimize the secondary migration mode of oil under different geological conditions. SUMMARY

[0004] The present application aims to provide a scheme for analyzing the secondary migration law of oil under different geological conditions.

[0005] In order to solve the above technical problems, the embodiment of the present application provides a method for analyzing the secondary migration mode of oil, comprising: obtaining a capillary number index representing the competition characteristics between capillary pressure and viscous force and a Bo number index representing the competition characteristics between buoyancy and capillary pressure of the secondary migration process of the oil to be evaluated by carrying out indoor physical experiments on the oil to be evaluated; determining the main power type of the oil to be evaluated by using a preset displacement pressure and buoyancy control migration mode identification chart according to the ratio of the capillary number index and the Bo number index; and determining the secondary migration mode of the fluid of the oil to be evaluated according to the main power type.

[0006] Preferably, the capillary number index is obtained by the following steps: establishing a capillary number index calculation model based on the viscous force difference between crude oil and formation two-phase fluid; and obtaining the capillary number index by indoor physical experiments based on the capillary number index calculation model.

[0007] Preferably, in the step of determining the fluid migration performance mode of the oil to be evaluated according to the ratio of the capillary number index to the Bo number index and using the preset displacement pressure and buoyancy controlled migration mode identification chart, when the ratio is greater than 1, it is determined that the main driving force of the current fluid is displacement pressure; and when the ratio is less than 1, it is determined that the main driving force of the current fluid is buoyancy.

[0008] Preferably, in the step of determining the fluid secondary migration mode of the oil to be evaluated according to the main driving force type, the fluid migration performance mode of the oil to be evaluated is determined, which includes: when the main driving force of the current fluid of the oil to be evaluated is displacement pressure, it is determined that the migration performance of the current fluid is macroscopic flow; and when the main driving force of the current fluid of the oil to be evaluated is buoyancy, it is determined that the migration performance of the current fluid is preferential path migration.

[0009] Preferably, in the step of determining the fluid secondary migration mode of the oil to be evaluated according to the main driving force type, the fluid migration performance mode of the oil to be evaluated and the migration characteristic analysis method applicable thereto are determined, which includes: when the main driving force of the current fluid of the oil to be evaluated is displacement pressure, it is determined that the migration performance of the current fluid is macroscopic flow, and the flow equation is applicable to analyze the migration characteristics; and when the main driving force of the current fluid of the oil to be evaluated is buoyancy, it is determined that the migration performance of the current fluid is preferential path migration, and the fluid potential method or percolation theory is applicable to analyze the migration characteristics.

[0010] Preferably, the displacement pressure and buoyancy controlled migration mode identification chart is divided into a displacement pressure controlled migration mode description region and a buoyancy controlled migration mode description region by a preset boundary line, and the boundary line is a straight line where the ratio of the capillary number index to the Bo number index is 1.

[0011] In another aspect, the embodiment of the present application also provides a system for analyzing the secondary migration mode of oil, which includes: a characteristic index obtaining module configured to obtain a capillary number index representing the competition characteristics between capillary pressure and viscous force and a Bo number index representing the competition characteristics between buoyancy and capillary pressure of oil to be evaluated in the secondary migration process by conducting indoor physical experiments on the oil to be evaluated; a driving force type analysis module configured to determine the main driving force type of the oil to be evaluated according to the ratio of the capillary number index to the Bo number index and using a preset displacement pressure and buoyancy controlled migration mode identification chart; and a migration mode analysis module configured to determine the fluid secondary migration mode of the oil to be evaluated according to the main driving force type.

[0012] Preferably, the power type analysis module is further configured to determine that the main power of the current fluid is displacement pressure when the ratio is greater than 1, and determine that the main power of the current fluid is buoyancy when the ratio is less than 1.

[0013] Preferably, the migration mode analysis module is further configured to determine that the migration of the current fluid exhibits macroscopic flow when the main power of the current fluid to be evaluated is displacement pressure, and determine that the migration of the current fluid exhibits preferential path migration when the main power of the current fluid to be evaluated is buoyancy.

[0014] Preferably, the migration mode analysis module is further configured to determine that the migration of the current fluid exhibits macroscopic flow when the main power of the current fluid to be evaluated is displacement pressure, and determine that the migration of the current fluid exhibits preferential path migration when the main power of the current fluid to be evaluated is buoyancy.

[0015] Compared with the prior art, one or more embodiments in the above solution can have the following advantages or beneficial effects:

[0016] The present application provides a method and system for analyzing the secondary migration mode of oil. The method and system determine the secondary migration mode of oil under different actual geodynamic conditions by using a discrimination chart, then select a corresponding migration simulation method according to the secondary migration mode of oil, dynamically analyze the secondary migration rule of oil, and finally simulate and determine the oil accumulation position by using a secondary migration calculation method suitable for different geological conditions, so as to more accurately and effectively determine the oil and gas enrichment area.

[0017] Other features and advantages of the present application will be set forth in the following description, and in part will become apparent to those skilled in the art from the description, or can be learned by practice of the present application. The objects and other advantages of the present application will be realized and achieved by means of the structures particularly pointed out in the description and claims. BRIEF DESCRIPTION OF DRAWINGS

[0018] The accompanying drawings are included to provide a further understanding of the present application, and constitute a part of the specification, illustrate embodiments of the present application, and are used to explain the present application together with the description. The drawings do not limit the present application.

[0019] Figure 1 A step schematic diagram of the method for analyzing the secondary migration mode of oil according to the embodiment of the present application.

[0020] Figure 2 An example diagram of the displacement pressure and buoyancy control migration mode discrimination chart in the method for analyzing the secondary migration mode of oil according to the embodiment of the present application.

[0021] Figure 3 A module block diagram of a system for analyzing a secondary migration mode of petroleum according to an embodiment of the present application. DETAILED DESCRIPTION

[0022] The embodiments of the present application will be described in detail with reference to the drawings and embodiments, by which the application applies technical means to solve technical problems and achieve technical effects. It should be noted that, unless there is a conflict, each embodiment in the present application and each feature in each embodiment can be combined with each other, and the technical solutions formed thereby are within the protection scope of the present application.

[0023] In addition, the steps shown in the flowchart of the drawings can be executed in a computer system such as a set of computer executable instructions. Moreover, although a logical order is shown in the flowchart, in some cases, the steps shown or described herein can be executed in an order different from that shown.

[0024] The terms used herein are merely used to describe specific embodiments and are not intended to limit exemplary embodiments. Unless the context clearly indicates otherwise, as used herein, the singular forms "a," "an," and "the" are intended to include the plural forms as well. It will be further understood that the terms "comprises" and / or "comprising," when used herein, specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0025] To solve the technical problems in the above background art, the present application provides a method and system for analyzing a secondary migration mode of petroleum. The system and method correct the Ca parameter through actual physical experiments and in combination with previous experimental results, and establish a secondary migration mode identification chart of petroleum using the corrected parameter, use the chart to divide the secondary migration mode of petroleum, and then select a suitable description method of secondary migration of petroleum, so as to define the mode and characteristics of secondary migration of petroleum, select a multi-item flow equation to describe the secondary migration of petroleum when the displacement pressure is the main driving force, and select a fluid potential method when the buoyancy is the main driving force. In this way, the present application can more effectively analyze the characteristics of secondary migration of petroleum, so as to better predict the location of petroleum enrichment.

[0026] Example One

[0027] Figure 1 A method step schematic diagram of a system for analyzing a secondary migration mode of petroleum according to an embodiment of the present application. The following refers to Figure 1The method for analyzing the secondary migration mode of petroleum (also referred to as a "secondary migration mode analysis method") described in the embodiments of the present application.

[0028] In step S110, the capillary number index and the Bo number index of the petroleum to be evaluated are obtained by performing a physical experiment in a laboratory on the petroleum to be evaluated.

[0029] In step S110 of the embodiments of the present application, a physical experiment in a laboratory is first performed on the petroleum to be evaluated, and the capillary number index and the Bo number index of the petroleum to be evaluated in the secondary migration process are calculated.

[0030] The secondary migration of petroleum is affected by many factors, such as particle size, injection pressure, fluid properties, gravitational acceleration, and the like. In actual conditions, it is difficult to analyze the complex relationship between these parameters by analyzing the secondary migration of petroleum with respect to a single factor. In fact, the key factors that control the migration mode of petroleum are only the capillary pressure, the viscous force, and the buoyancy. Therefore, the relationship between these three factors can be described by using the capillary number (Ca) and the Bond number (Bo), so that the migration mode of the petroleum to be evaluated can be determined by analyzing these three parameters.

[0031] In the field of analysis of the migration mode of petroleum, it has been proposed to use the Bond number and the capillary number to comprehensively analyze the relationship between different factors in the secondary migration process. This method provides a physical basis for studying the secondary migration mode of petroleum. Thereafter, the Bond number and the capillary number have been used as a measurement index for determining the migration mode of petroleum in the secondary migration process, the distribution of the migration channel, and the change of the migration channel. Furthermore, the Bo number and the Ca number have been used to analyze the characteristics of the secondary migration of petroleum.

[0032] Thus, in step S110, the capillary number index and the Bo number index of the petroleum to be evaluated in the secondary migration process are calculated by performing a physical experiment in a laboratory on the petroleum to be evaluated. The capillary number index is used to represent the competition characteristics between the capillary pressure and the viscous force of the petroleum in the secondary migration process. The Bo number index is used to represent the competition characteristics between the buoyancy and the capillary pressure of the petroleum in the secondary migration process.

[0033] Because oil and gas migration is a slow process in geological process, the effect of viscous force cannot be ignored in the secondary migration analysis process, and in the past Ca number analysis, the viscous force parameter is directly selected as the oil viscous force parameter for analysis. In the actual oil and gas migration process, the oil migrates in the formation water under different salinity conditions, and the difference between the oil and formation water viscous forces must be considered to accurately reflect the real migration dynamics process, so the viscous force difference is used instead of the viscous force. However, the actual indoor physical experiment and the characteristics of the episodic migration show that the viscous force cannot be ignored in the secondary migration process of the oil.

[0034] Therefore, the capillary number index described in the embodiments of the present application needs to modify and optimize the viscous force parameter on the basis of the traditional capillary number calculation model, so as to obtain the capillary number index calculated by the modified capillary number calculation model to analyze the secondary migration mode of the oil fluid.

[0035] In one embodiment, the capillary number index required in step S110 is obtained by the following steps: establishing a capillary number index calculation model based on the viscous force difference of the crude oil and the formation two-phase fluid; and then, based on the capillary number index calculation model, obtaining the capillary number index through the indoor physical experiment.

[0036] Wherein, by redefining μ = μ2- μ1, considering the viscous force difference of the oil and formation water two-phase fluid, the modified capillary number index is marked as Ca'.

[0037] The capillary number index calculation model is expressed by the following expression:

[0038]

[0039] Wherein, Ca' represents the capillary number index, μ represents the difference between the viscous forces of the oil and the formation two-phase fluid to be evaluated, v represents the Darcy rate of the oil to be evaluated, a represents the characteristic pore throat, γ represents the interfacial tension, and k represents the absolute permeability. Generally, without considering the influence of the buoyancy factor, when Ca << 1, the system shows capillary fingering; and when Ca >> 1, the system shows viscous fingering.

[0040] The Bond number (Bo number) index is expressed by the following expression:

[0041]

[0042] Wherein, Bo represents the Bo number index, Δρ represents the buoyancy difference of the oil in the secondary migration process, and g represents the acceleration of gravity.

[0043] After the calculation of the capillary number index and the Bo number index is completed, step S120 is entered.

[0044] Step S120 determines the main power type of the to-be-evaluated petroleum according to the ratio of the capillary number index and the Bo number index of the to-be-evaluated petroleum obtained in step S110, and uses the preset displacement pressure and buoyancy controlled migration mode identification chart to determine the main power type of the to-be-evaluated petroleum.

[0045] Figure 2 An example chart of the displacement pressure and buoyancy controlled migration mode identification chart used in the method for determining the secondary migration analysis mode of petroleum according to an embodiment of the present application is shown in FIG. 1. As shown in FIG. 1, the displacement pressure and buoyancy controlled migration mode identification chart according to an embodiment of the present application is established using the Bo number index and the newly defined capillary number index. In the embodiment of the present application, the displacement pressure and buoyancy controlled migration mode identification chart is divided into a displacement pressure controlled migration mode description region and a buoyancy controlled migration mode description region by a preset boundary line. The boundary line between the two description regions is a straight line where the ratio of the capillary number index (Ca') and the Bo number index (Bo) is 1, so that the migration mode identification chart is divided into two regions by the boundary line between the displacement pressure controlled migration mode and the buoyancy controlled migration mode. Figure 2

[0046] As shown in FIG. 1, the data points in the displacement pressure and buoyancy controlled migration mode identification chart are physical experimental data points. The gray data points are macroscopic flow modes under displacement pressure control, and the black data points are dominant path migration modes under buoyancy control. Figure 2

[0047] In one embodiment, the main power type of the to-be-evaluated petroleum is determined by calculating the ratio of the capillary number index and the Bo number index of the to-be-evaluated petroleum, and using the pre-constructed displacement pressure and buoyancy controlled migration mode identification chart.

[0048] In the first embodiment, when the ratio of the capillary number index and the Bo number index of the to-be-evaluated petroleum is greater than 1, it is determined that the main power of the to-be-evaluated petroleum fluid is displacement pressure.

[0049] In the second embodiment, when the ratio of the capillary number index and the Bo number index of the to-be-evaluated petroleum is less than 1, it is determined that the main power of the to-be-evaluated petroleum fluid is buoyancy.

[0050] Step S130 determines the secondary migration mode of the to-be-evaluated petroleum according to the main power type of the to-be-evaluated petroleum fluid determined in step S120.

[0051] ​​In a first embodiment of step S130, the mode of fluid migration performance of the petroleum fluid to be evaluated is determined according to the type of the main driving force of the current petroleum fluid to be evaluated. Specifically, when the main driving force of the current petroleum fluid to be evaluated is displacement pressure, it is determined that the migration performance of the current petroleum fluid is macroscopic flow. When the main driving force of the current petroleum fluid to be evaluated is buoyancy, it is determined that the migration performance of the current petroleum fluid is preferential path migration.

[0052] In a second embodiment of step S130, the mode of fluid migration performance of the petroleum fluid to be evaluated and the applicable migration characteristic analysis method are determined according to the type of the main driving force of the current petroleum fluid to be evaluated. Specifically, when the main driving force of the current petroleum fluid to be evaluated is displacement pressure, it is determined that the migration performance of the current petroleum fluid is macroscopic flow, and the flow equation is applicable to analyze the migration characteristics. When the main driving force of the current petroleum fluid to be evaluated is buoyancy, it is determined that the migration performance of the current petroleum fluid is preferential path migration, and the fluid potential method or percolation theory is applicable to analyze the migration characteristics.

[0053] In this way, when the ratio of Ca' and Bo is greater than 1, the displacement pressure is the main driving force, the fluid migration performance is macroscopic flow, and the flow equation is suitable for analyzing the migration characteristics; when the ratio of Ca' and Bo is less than 1, the buoyancy is the main driving force, the fluid migration performance is preferential path migration, and the fluid potential method is suitable for analyzing the secondary migration characteristics of the petroleum under this condition, and the percolation theory can also be used for analysis. Thus, the embodiments of the present application use the above steps S110-S130 to analyze the mode of secondary migration of the petroleum fluid to be evaluated, and further more accurately describe the secondary migration characteristics of the petroleum.

[0054] Example Two

[0055] Based on the above secondary migration mode analysis method, the embodiments of the present application also provide a system for analyzing the mode of secondary migration of petroleum (also referred to as a "secondary migration mode analysis system"). The secondary migration mode analysis system is used to implement the secondary migration mode analysis method as described above.

[0056] Figure 3 The module block diagram of the system for analyzing the mode of secondary migration of petroleum of the embodiments of the present application is shown in FIG. 1. As shown in FIG. 1, the secondary migration mode analysis system of the embodiments of the present application includes a characteristic index obtaining module 31, a driving force type analysis module 32, and a migration mode analysis module 33. Figure 3

[0057] ​Specifically, the characteristic index obtaining module 31 is configured to obtain the capillary number index representing the competition between the capillary pressure and the viscous force and the Bo number index representing the competition between the buoyancy and the capillary pressure of the oil to be evaluated in the secondary migration process by performing the indoor physical experiment on the oil to be evaluated according to the method described in step S110; the dynamic type analyzing module 32 is configured to determine the main dynamic type of the oil to be evaluated according to the ratio of the capillary number index to the Bo number index by using the preset displacement pressure and buoyancy control migration mode identification chart; and the migration mode analyzing module 33 is configured to determine the fluid secondary migration mode of the oil to be evaluated according to the main dynamic type according to the method described in step S130.

[0058] Further, the dynamic type analyzing module 32 is further configured to determine that the main driving force of the current oil fluid is the displacement pressure when the ratio of the capillary number index to the Bo number index is greater than 1, or determine that the main driving force of the current oil fluid is the buoyancy when the ratio of the capillary number index to the Bo number index is less than 1.

[0059] Further, in the first embodiment of the migration mode analyzing module 33, the migration mode analyzing module 33 is further configured to determine that the migration of the current oil fluid is in the form of macroscopic flow when the main driving force of the current oil fluid to be evaluated is the displacement pressure, or determine that the migration of the current oil fluid is in the form of the preferential path migration mode when the main driving force of the current oil fluid to be evaluated is the buoyancy.

[0060] Further, in the second embodiment of the migration mode analyzing module 33, the migration mode analyzing module 33 is further configured to determine that the migration of the current oil fluid is in the form of macroscopic flow when the main driving force of the current oil fluid to be evaluated is the displacement pressure, which is suitable for analyzing the migration characteristics by using the flow equation, or determine that the migration of the current oil fluid is in the form of the preferential path migration mode when the main driving force of the current oil fluid to be evaluated is the buoyancy, which is suitable for analyzing the migration characteristics by using the fluid potential method or the percolation theory.

[0061] The application discloses a method and system for analyzing the secondary migration mode of oil.

[0062] The above merely describes preferred specific embodiments of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art can easily think of changes or replacements within the technical scope disclosed by the present application, which should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

[0063] In the description of the present application, unless otherwise specified and limited, the meaning of "a plurality of" is two or more; the orientation or positional relationship indicated by the terms "upper", "lower", "left", "right", "inner", "outer", "front end", "rear end", "head", "tail" and the like is based on the orientation or positional relationship shown in the drawings, and is merely for the purpose of facilitating the description of the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second", "third" and the like are only for the purpose of description and cannot be understood as indicating or implying relative importance.

[0064] In the description of the present application, it should be noted that, unless otherwise specified and limited, the terms "connected", "connected" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0065] It should be understood that the embodiments disclosed herein are not limited to the specific structure, processing steps or materials disclosed herein, but extend to equivalent alternatives of these features that are understood by those skilled in the relevant art. It should also be understood that the terms used herein are for the purpose of describing specific embodiments only and are not meant to be limiting.

[0066] The phrase "one embodiment" or "an embodiment" appearing in the specification means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the application. Therefore, the appearance of the phrase "one embodiment" or "an embodiment" throughout the specification does not necessarily refer to the same embodiment.

[0067] Although the embodiments disclosed by the present application are as described above, the content described is only the embodiments adopted for the purpose of facilitating the understanding of the present application, and is not intended to limit the present application. Any person skilled in the art can make any modification and change in the form and details without departing from the spirit and scope of the present application, but the patent protection scope of the present application should be subject to the scope defined by the claims.

Claims

1. A method for analyzing secondary migration patterns of petroleum, characterized in that, include: By conducting indoor physical experiments on the petroleum to be evaluated, we can obtain the capillary number index, which characterizes the competition between capillary pressure and viscous force, and the Bo number index, which characterizes the competition between buoyancy and capillary pressure, during the secondary migration process of the petroleum to be evaluated. Based on the ratio of the capillary number index to the Bo number index, the main dynamic type of the oil to be evaluated is determined by using a preset displacement pressure and buoyancy control migration pattern identification chart. Based on the primary power type, the fluid secondary transport mode of the petroleum to be evaluated is determined.

2. The method according to claim 1, characterized in that, The capillary count index is obtained through the following steps: A capillary number index calculation model is established based on the viscosity difference between crude oil and formation two-phase fluid. Based on the capillary count calculation model, the capillary count was obtained through indoor physical experiments.

3. The method according to claim 1 or 2, characterized in that, The step of determining the fluid migration pattern of the oil to be evaluated based on the ratio of the capillary number index to the Bo number index, using a preset displacement pressure and buoyancy-controlled migration pattern identification chart, includes: When the ratio is greater than 1, the primary driving force of the current fluid is determined to be the displacement pressure; When the ratio is less than 1, the primary driving force of the current fluid is determined to be buoyancy.

4. The method according to claim 3, characterized in that, The step of determining the fluid secondary transport pattern of the petroleum to be evaluated based on the primary dynamic type includes: determining the fluid transport behavior pattern of the petroleum to be evaluated, including: When the primary driving force of the current petroleum fluid to be evaluated is displacement pressure, the current fluid migration is determined to be macroscopic flow. When the primary driving force of the oil fluid to be evaluated is buoyancy, the current fluid migration is determined to be a dominant path migration mode.

5. The method according to claim 3, characterized in that, The step of determining the secondary fluid migration mode of the petroleum to be evaluated based on the primary dynamic type further includes: determining the fluid migration behavior mode of the petroleum to be evaluated and the applicable migration characteristic analysis method, including: When the primary driving force of the oil fluid to be evaluated is the displacement pressure, the current fluid migration is determined to be macroscopic flow, which is suitable for analyzing migration characteristics using flow equations. When the primary driving force of the oil fluid to be evaluated is buoyancy, determining that the current fluid migration exhibits a dominant path migration pattern is suitable for analyzing migration characteristics using fluid potential methods or percolation theory.

6. The method according to any one of claims 1 to 5, characterized in that, The displacement pressure and buoyancy control movement pattern recognition board is divided into a displacement pressure control movement pattern description area and a buoyancy control movement pattern description area by a preset dividing line, which is a straight line where the ratio of the capillary number index to the Bo number index is 1.

7. A system for analyzing secondary migration patterns of petroleum, characterized in that, include: The feature index acquisition module is configured to obtain the capillary number index, which characterizes the competitive characteristics between capillary pressure and viscosity, and the Bo number index, which characterizes the competitive characteristics between buoyancy and capillary pressure, by conducting indoor physical experiments on the oil to be evaluated during the secondary migration process. The dynamic type analysis module is configured to determine the main dynamic type of the oil to be evaluated by using a preset displacement pressure and buoyancy control migration pattern identification chart based on the ratio of the capillary number index to the Bo number index. The transport pattern analysis module is configured to determine the fluid secondary transport pattern of the petroleum to be evaluated based on the primary power type.

8. The system according to claim 7, characterized in that, The power type analysis module is also configured to: When the ratio is greater than 1, the primary driving force of the current fluid is determined to be the displacement pressure; When the ratio is less than 1, the primary driving force of the current fluid is determined to be buoyancy.

9. The system according to claim 8, characterized in that, The transport pattern analysis module is also configured to: When the primary driving force of the current petroleum fluid to be evaluated is displacement pressure, the current fluid migration is determined to be macroscopic flow. When the primary driving force of the oil fluid to be evaluated is buoyancy, the current fluid migration is determined to be a dominant path migration mode.

10. The system according to claim 8, characterized in that, The transport pattern analysis module is also configured to: When the primary driving force of the oil fluid to be evaluated is the displacement pressure, the current fluid migration is determined to be macroscopic flow, which is suitable for analyzing migration characteristics using flow equations. When the primary driving force of the oil fluid to be evaluated is buoyancy, determining that the current fluid migration exhibits a dominant path migration pattern is suitable for analyzing migration characteristics using fluid potential methods or percolation theory.

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