Method and system for predicting maximum height of oil column of sandstone reservoir

Abstract

The invention discloses a method and system for predicting the maximum height of an oil column of an upper-generation lower-storage type sandstone reservoir, and the method comprises the steps: building a dynamic critical equilibrium relational expression which takes hydrocarbon expulsion intensity and oil column formation height as unknown quantities and is used for representing an oil column formation condition and a force equilibrium relation according to the basic parameters of a hydrocarbon source rock stratum to be researched; according to pyrolysis experiment parameter data of multiple wells in the hydrocarbon source rock stratum to be researched, hydrocarbon expulsion intensity at different depths is calculated; and substituting the hydrocarbon expulsion intensities at different depths into the dynamic critical equilibrium relational expression so as to obtain the maximum oil column formation height at different depths. According to the method, the reliability and the accuracy of predicting the maximum height of the oil column of the upper-growing lower-storage type sandstone reservoir are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of oil reservoir scale and resource evaluation, and particularly relates to a method and system for predicting the maximum height of an oil column in an up-growth and down-accumulation type sandstone reservoir. BACKGROUND

[0002] The height of the oil column reflects the longitudinal distribution ability of the crude oil in the formation, and determines the enrichment degree of the crude oil in the trap and zone. The higher the oil column, the larger the oil reservoir reserves, and the greater the exploration and development value. Therefore, accurately predicting the maximum height of the oil column has important guiding significance for evaluating the scale of the up-growth and down-accumulation type sandstone reservoir. The up-growth and down-accumulation type oil and gas accumulation mechanism is that, during the process of hydrocarbon generation and expulsion of source rocks, when the pressure of the upper formation continuously increases to the point that oil and gas cannot break through upward, a large amount of oil and gas can accumulate in the lower high-quality reservoir. However, due to the differences in the pressure increase of the hydrocarbon generation of source rocks at different times and depths, the maximum height of the oil column in the lower sandstone reservoir is also different. Therefore, it is of important theoretical and practical significance to establish a scientific and effective method for predicting the maximum height of the oil column in the up-growth and down-accumulation type sandstone reservoir from the mechanism of accumulation dynamics, so as to comprehensively evaluate the potential of oil and gas resources and promote the increase of reserves and production of oilfields.

[0003] For predicting the maximum height of the oil column in the up-growth and down-accumulation type sandstone reservoir, scholars at home and abroad mainly use statistical analysis and accumulation dynamics analysis. Statistical analysis is to obtain the paleo-overpressure value through the acoustic travel time and other logging response characteristics, and to obtain the prediction value by fitting the source-reservoir distance of the oil show section with the distribution function curve method. Accumulation dynamics analysis is to determine the dynamic balance relationship between the driving force and the resistance by analyzing the driving force system of the oil column formation, to establish a mechanical equilibrium equation, and to obtain the height of the oil column.

[0004] Predicting the maximum height of the oil column is a difficulty in the evaluation of the up-growth and down-accumulation type sandstone oil and gas resources, and is a key factor restricting the future exploration and development direction of oil and gas. It is found in the practice of oil reservoir exploration that the maximum height of the oil column in the up-growth and down-accumulation type sandstone reservoir is proportional to the overpressure value of the source rock series, but there are many influencing factors, and the statistical analysis only uses the relationship between the two to obtain the prediction value by function fitting, which completely deviates from the actual geological conditions. The accumulation dynamics analysis predicts the maximum height of the oil column from the perspective of mechanics, but the force analysis of the target object is not accurate and comprehensive, which leads to a large deviation of the prediction result.

[0005] Therefore, the prior art needs to provide a scheme for reasonably and objectively predicting the maximum height of the oil column in the up-growth and down-accumulation type sandstone reservoir, so as to accurately and effectively evaluate the scale of the oil reservoir and the reserves. SUMMARY

[0006] The present application aims at providing a scheme for reasonably and objectively predicting the maximum height of oil column in the upper-source-lower-reservoir type sandstone reservoir, so as to accurately and effectively evaluate the reservoir scale and reserves.

[0007] To solve the above technical problems, the present application provides a method for predicting the maximum height of oil column in the upper-source-lower-reservoir type sandstone reservoir, comprising: establishing a dynamic critical balance relationship formula taking the hydrocarbon expulsion intensity and the oil column formation height as unknown quantities and used for representing the oil column formation condition and the force balance relationship according to the basic parameters of the source rock layer to be studied; calculating the hydrocarbon expulsion intensity at different depths according to the pyrolysis experimental parameter data of multiple wells in the source rock layer to be studied; and substituting the hydrocarbon expulsion intensity at different depths into the dynamic critical balance relationship formula, so as to obtain the maximum height of oil column formation at different depths.

[0008] Preferably, the dynamic critical balance relationship formula is formed by the balance relationship between the power and the resistance according to the seepage theory, taking the sum of the oil generation pressure increase and the oil column gravity as the power, and taking the sum of the capillary force, the fluid pressure and the fluid resistance as the resistance, wherein the basic parameters include the burial depth and thickness of the well in the source rock layer to be studied, the time experienced by the source rock during the hydrocarbon generation and expulsion period, the distance from the hydrocarbon expulsion center to the edge of the source rock, the source rock area, the permeability test data of the source rock layer, the crude oil viscosity and density test data in the sandstone reservoir, and the rock physical characteristic parameters of the sandstone reservoir, the rock physical characteristic parameters including the wetting angle, the interfacial tension and the pore throat radius at different burial depths.

[0009] Preferably, the dynamic critical balance relationship formula is expressed by the following expression:

[0010]

[0011] P g =ρ o Hg

[0012]

[0013] P f =ρ w g(h+H)

[0014] P d =α·H

[0015] △P+P g =f+P f +P d

[0016] Wherein, ΔP represents the oil generation pressure increase; S represents the source rock area; μ represents the crude oil viscosity; L represents the distance from the hydrocarbon expulsion center to the edge of the source rock; Q i represents the hydrocarbon expulsion amount per unit time; Qe represents the amount of hydrocarbon expulsion of source rock; Δt represents the time experienced by source rock in the key moment of hydrocarbon generation-expulsion-migration-accumulation; K represents the permeability of source rock; ρ o represents the density of crude oil; q e represents the hydrocarbon expulsion intensity per unit area; P g represents the oil column gravity boost; m represents the oil column mass; g represents the gravity acceleration; H represents the oil and gas column height; f represents the capillary force; r represents the reservoir pore throat radius; σ represents the interfacial tension; θ represents the wetting angle; P f represents the fluid pressure; ρ w represents the water density; h represents the oil and gas column top depth; P d represents the fluid resistance when the oil and gas column is downwardly transported; α represents the fluid attenuation gradient.

[0017] Preferably, in the step of calculating the hydrocarbon expulsion intensity at different depths according to the pyrolysis experimental parameter data of multiple wells in the source rock layer to be studied, the following steps are included: collecting core samples at different periods and coring depths of multiple wells in the source rock layer to be studied and performing pyrolysis experiments thereon to obtain pyrolysis experimental parameter data, the pyrolysis experimental parameter data including free hydrocarbon content, pyrolysis hydrocarbon content, organic matter abundance and organic matter maturity; correcting the free hydrocarbon content according to the pyrolysis experimental parameter data; calculating the hydrocarbon generation potential index distribution characteristics in the source rock layer by using the corrected pyrolysis experimental parameter data, so as to form a hydrocarbon expulsion rate curve; and calculating the hydrocarbon expulsion intensity at different depth sections according to the hydrocarbon expulsion rate curve.

[0018] Preferably, in the step of calculating the hydrocarbon generation potential index distribution characteristics in the source rock layer by using the corrected pyrolysis experimental parameter data, so as to form a hydrocarbon expulsion rate curve, the following steps are included: calculating the hydrocarbon generation potential index at different periods and depths in the source rock layer according to the corrected pyrolysis experimental parameter data; and calculating the hydrocarbon expulsion rate at different periods and depths by using the following expression according to the hydrocarbon generation potential index at different periods and depths:

[0019]

[0020] q o =GPI o -GPI r ·γ

[0021] wherein, GPI o represents the original hydrocarbon generation potential index when the hydrocarbon generation potential index does not exceed the hydrocarbon expulsion threshold; GPI r represents the remaining hydrocarbon generation potential index when the hydrocarbon generation potential index reaches and exceeds the hydrocarbon expulsion threshold; γ represents the recovery coefficient; q o represents the hydrocarbon expulsion rate at different depths.

[0022] Preferably, in the step of calculating the hydrocarbon expulsion intensity at different depth segments according to the hydrocarbon expulsion ratio curve, the following steps are included:

[0023]

[0024] wherein q e represents the hydrocarbon expulsion intensity; H o represents the thickness of the source rock; q o (Ro) represents the hydrocarbon expulsion ratio corresponding to the organic matter maturity Ro at the corresponding depth; p s represents the average density of the source rock; R oe1 , R oe2 respectively represent the lower limit value and the upper limit value of the corresponding organic matter maturity range within the depth range of the current depth segment; TOC represents the organic matter abundance.

[0025] Preferably, the hydrocarbon generation potential index is the ratio of the first value at the corresponding period and depth to the organic matter abundance, and the first value is the sum of the corrected free hydrocarbon content and the pyrolysis hydrocarbon content.

[0026] Preferably, according to the pyrolysis experimental parameter data, the free hydrocarbon content is corrected by using the following expression:

[0027]

[0028] wherein S1 represents the original free hydrocarbon content, S1 * represents the corrected free hydrocarbon content, and Ro represents the organic matter maturity.

[0029] In another aspect, the embodiment of the present application also provides a system for predicting the maximum height of the oil column in the upper-generating and lower-storing sandstone reservoir, which comprises: a balance relationship formula generation module configured to establish a dynamic critical balance relationship formula taking the hydrocarbon expulsion intensity and the oil column formation height as unknown quantities and used to represent the oil column formation condition and the force balance relationship according to the basic parameters of the source rock layer to be studied; a hydrocarbon expulsion intensity calculation module configured to calculate the hydrocarbon expulsion intensity at different depths according to the pyrolysis experimental parameter data of multiple wells in the source rock layer to be studied; and an oil column height prediction module configured to substitute the hydrocarbon expulsion intensity at the different depths into the dynamic critical balance relationship formula, so as to obtain the maximum height of the oil column formation at the different depths.

[0030] In addition, the embodiment of the present application provides a computer readable storage medium which stores computer executable instructions, and the computer executable instructions are executed by a processor to realize the steps of the method described above.

[0031] Compared with the prior art, one or more embodiments in the above scheme can have the following advantages or beneficial effects:

[0032] The application provides a method and system for predicting the maximum height of an oil column in a sandstone reservoir with a pattern of upper source and lower storage.

[0033] Additional features and advantages of the application will be set forth in the description that follows, and in part will be apparent from the description, or can be learned by practice of the application. The objectives and other advantages of the application will be realized and attained by the structure particularly pointed out in the description and claims. BRIEF DESCRIPTION OF DRAWINGS

[0034] The accompanying drawings are included to provide a further understanding of the application and are incorporated in and constitute a part of this specification, illustrate embodiments of the application and together with the description serve to explain the principles of the application. In the drawings:

[0035] Figure 1 A schematic diagram of the steps of the method for predicting the maximum height of an oil column in a sandstone reservoir with a pattern of upper source and lower storage according to an embodiment of the application.

[0036] Figure 2 A schematic diagram of the construction principle of the dynamic critical balance relationship in the method for predicting the maximum height of an oil column in a sandstone reservoir with a pattern of upper source and lower storage according to an embodiment of the application.

[0037] Figure 3 An example diagram of the thickness distribution characteristics of source rocks in the method for predicting the maximum height of an oil column in a sandstone reservoir with a pattern of upper source and lower storage according to an embodiment of the application.

[0038] Figure 4 An example diagram of the hydrocarbon generation potential index distribution characteristics and the hydrocarbon expulsion rate curve in the method for predicting the maximum height of an oil column in a sandstone reservoir with a pattern of upper source and lower storage according to an embodiment of the application.

[0039] Figure 5 An example diagram of the hydrocarbon expulsion intensity distribution characteristics of source rocks in the method for predicting the maximum height of an oil column in a sandstone reservoir with a pattern of upper source and lower storage according to an embodiment of the application.

[0040] Figure 6 A module block diagram of the system for predicting the maximum height of an oil column in a sandstone reservoir with a pattern of upper source and lower storage according to an embodiment of the application. DETAILED DESCRIPTION

[0041] The embodiments of the present application will be described in detail below with reference to the accompanying drawings and examples, so that the application can be understood as how to solve the technical problems and achieve the technical effects by using technical means. 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 formed technical solutions are all within the protection scope of the present application.

[0042] In addition, the steps shown in the flowchart of the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions. Moreover, although the 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.

[0043] The terms used herein are only used to describe specific embodiments and are not intended to limit the exemplary embodiments. Unless the context clearly indicates otherwise, the singular forms "a", "an", and "the" used herein are also intended to include the plural. It should also be understood that the terms "include" and / or "contain" used herein specify the presence of stated features, integers, steps, operations, units and / or components, without excluding the presence or addition of one or more other features, integers, steps, operations, units, components and / or combinations thereof.

[0044] To solve the technical problems in the background art, the present application implements a method and system for predicting the maximum height of the oil column in the sandstone reservoir with the source rock above the reservoir. The method and system are based on the dynamic accumulation dynamics mechanism, and take the oil pressure increase and the oil column gravity as the power, and take the capillary force, fluid pressure (buoyancy, hydrodynamic force) and fluid attenuation power as the resistance, to establish the method for predicting the maximum height of the oil column in the sandstone reservoir with the source rock above the reservoir, so as to determine the height of the oil column formed by the source rock at different depths. The present application can provide a basis for oil and gas resource evaluation, and has certain universal applicability.

[0045] Example One

[0046] Figure 1 The steps of the method for predicting the maximum height of the oil column in the sandstone reservoir with the source rock above the reservoir according to the embodiments of the present application are shown in the schematic diagram. The following refers to the accompanying drawings Figure 1 The specific steps of the method for predicting the maximum height of the oil column in the sandstone reservoir with the source rock above the reservoir (also referred to as "oil column height prediction method") according to the embodiments of the present application are described.

[0047] Step S110, according to the basic parameters of the source rock layer to be studied, a dynamic critical balance relationship formula is established, which takes the hydrocarbon discharge intensity and the oil column formation height as unknown quantities and is used to characterize the oil column formation conditions and force balance relationship.

[0048] In the embodiments of the present application, the basic parameters include, but are not limited to, the crude oil viscosity and density test data in the sandstone reservoir, the time experienced by the source rock during the hydrocarbon generation and expulsion period, the distance from the center to the edge of the source rock, the area of the source rock, the permeability test data of the source rock layer, the buried depth and thickness of the well in the source rock layer to be studied, and the petrophysical characteristic parameters of the sandstone reservoir. The petrophysical characteristic parameters include, but are not limited to, the wetting angle, the interfacial tension, and the pore throat radius at different depths.

[0049] In the embodiments of the present application, referring to Figure 2 The dynamic critical balance relationship is a relationship based on the percolation theory, takes the sum of the oil column gravity and the oil pressure as the power, and takes the sum of the capillary force, the fluid pressure and the fluid resistance as the resistance, and forms the dynamic critical balance relationship by establishing the balance between the power and the resistance. The dynamic critical balance relationship model takes the hydrocarbon expulsion intensity and the oil column formation height as unknown quantities, is a model for predicting the maximum height of the oil column in the upper-source and lower-reservoir type sandstone reservoir, and can represent the oil column formation conditions and the force balance relationship.

[0050] Specifically, the buried depth and thickness of the well in the source rock layer in the source rock in the region to be studied are collected (see Figure 3 ); the time experienced by the source rock during the key hydrocarbon expulsion period, the distance from the center to the edge of the source rock, and the area of the source rock in the region to be studied; the crude oil viscosity and density test data in the sandstone reservoir under the source rock layer in the region to be studied are collected; the permeability test data of the source rock layer in the region to be studied are collected; the petrophysical characteristic parameters of the sandstone reservoir in the region to be studied, including the wetting angle, the interfacial tension, and the pore throat radius at different depths, are collected; and finally, the dynamic critical balance relationship is established based on the above data information collected and according to the critical conditions for the oil column formation and the force balance relationship.

[0051] In the embodiments of the present application, the dynamic critical balance relationship takes the oil pressure, the hydrocarbon expulsion intensity, the oil column gravity, the oil and gas column height, the capillary force, the fluid pressure, and the fluid resistance as unknown quantities.

[0052] In one embodiment, the dynamic critical balance relationship is expressed by the following expression:

[0053]

[0054] P f =P w +ρ w gH=ρ w g(h+H) (4)

[0055] P d =α·H (5)

[0056] △P+P g =f+P f +P d (6)

[0057] Where ΔP represents the oil generation pressurization, in Pa; S represents the area of ​​the source rock, in km². 2 μ represents crude oil viscosity, in mPa·s; L represents the distance from the hydrocarbon expulsion center to the edge of the source rock, in meters; Q i This represents the amount of hydrocarbons emitted per unit time, expressed in m³. 3 / s;Q e The value of ρ represents the amount of hydrocarbons expelled from the source rock, in tons (t); Δt represents the time elapsed during the critical moments of hydrocarbon generation, expulsion, transport, and accumulation in the source rock, in seconds (s); K represents the permeability of the source rock, in mD; ρ o This indicates the density of crude oil, expressed in g / cm³. 3 ;q e Hydrocarbon emission intensity per unit area, in units of 10. 8 t / km 2 ;P g The pressure is expressed as Pa (Pa) due to gravity; m represents the mass of the oil column in tons (t); and g represents the acceleration due to gravity in meters per second (m / s²). 2 H represents the height of the oil and gas column, in meters (m); f represents the capillary force, in Pa; r represents the reservoir pore throat radius, in μm; σ represents the interfacial tension, in N / m; θ represents the wetting angle, in degrees (°); P f P represents fluid pressure, with the unit being Pa; w ρ is the hydrostatic pressure, measured in Pa. w This indicates the density of water, expressed in g / cm³. 3 h represents the depth of the top of the oil and gas column, in meters; P d The value represents the fluid resistance during the downward transport of the oil and gas column, expressed in Pa; α represents the fluid attenuation gradient, typically taken as 0.0107 MPa / m.

[0058] Therefore, after completing the construction of the dynamic critical equilibrium relationship, we proceed to step S120.

[0059] Step S120: Calculate the hydrocarbon expulsion intensity at different depths based on the pyrolysis experimental parameter data of multiple wells drilled into the source rock formation to be studied.

[0060] In step S120, the first step is to drill multiple wells into the source rock formation to be studied, collect core samples from these wells under different conditions of different periods and core depths, and conduct pyrolysis experiments on these core samples to obtain pyrolysis experimental parameter data at different periods and core depths (burial depths).

[0061] In the embodiment of the present application, the pyrolysis experiment parameter data comprises: free hydrocarbon content (S1 value), pyrolysis hydrocarbon content (S2 value), organic matter abundance (TOC), and organic matter maturity R O .

[0062] In addition, in the first step, a quantitative change relationship between the organic matter maturity Ro and the burial depth in the source rock layer of the area to be studied needs to be established, that is, the relationship between the organic matter maturity and the depth.

[0063] In the second step, the original free hydrocarbon content in the original pyrolysis experiment parameter data is corrected according to the original pyrolysis experiment parameter data at different periods and burial depths obtained in the first step.

[0064] According to the pyrolysis experiment parameter data, the free hydrocarbon content is corrected by using the following expression:

[0065]

[0066] In the expression, S1 represents the original free hydrocarbon content (that is, the original soluble hydrocarbon content), S1 * represents the corrected free hydrocarbon content (that is, the actual residual liquid hydrocarbon amount in the source rock), and Ro represents the organic matter maturity (that is, vitrinite reflectance).

[0067] In the third step, the hydrocarbon generation potential index distribution characteristics in the source rock layer are calculated by using the corrected pyrolysis experiment parameter data, so as to form the hydrocarbon expulsion rate curve.

[0068] In the third step, first, the hydrocarbon generation potential index under different period and depth combination conditions in the source rock layer is calculated according to the corrected pyrolysis experiment parameter data at different periods and burial depths, so as to obtain the hydrocarbon generation potential index distribution characteristics.

[0069] Since the relationship between the organic matter maturity and the depth is established in the first step, the hydrocarbon generation potential index under different period and organic matter maturity combination conditions can also be obtained in the third step, so as to obtain the corresponding hydrocarbon generation potential index distribution characteristics, as shown in the left graph in FIG. 1. Figure 4

[0070] In the embodiment of the present application, the hydrocarbon generation potential index is the ratio of a first value to the organic matter abundance under the corresponding period and depth (or organic matter maturity), wherein the first value is the sum of the corrected free hydrocarbon content and the pyrolysis hydrocarbon content.

[0071]

[0072] In the expression, A represents the hydrocarbon generation potential index, S2 represents the pyrolysis hydrocarbon content in the original pyrolysis experiment parameter data, and TOC represents the organic matter abundance in the original pyrolysis experiment parameter data. ​

[0073] Then, the third step will calculate the hydrocarbon expulsion rate at different times and depths (or organic matter maturity) based on the hydrocarbon generation potential index at different times and depths (or organic matter maturity). By fitting the hydrocarbon expulsion rate at different depths (or organic matter maturity) at the same time, a hydrocarbon expulsion rate curve for different times will be formed.

[0074] In calculating the hydrocarbon expulsion rate curve, the hydrocarbon generation potential method is used. This method is based on the principle that, in the quantitative evaluation of source rock pyrolysis, the hydrocarbon generation potential of the source rock is usually represented by the sum of soluble hydrocarbons (S1) and cracked hydrocarbons (S2). In this embodiment of the invention, a comprehensive pyrolysis parameter, namely the hydrocarbon generation potential index "(S1)", is used. * The hydrocarbon generation potential of the source rock is characterized by "+S2) / TOC".

[0075] When the hydrocarbon generation potential index of a source rock begins to decrease during geological evolution, it indicates that hydrocarbons are beginning to be expelled. The corresponding burial depth or organic matter maturity represents the hydrocarbon expulsion threshold of the source rock. By studying the changes in the hydrocarbon generation potential index on geological profiles, the hydrocarbon expulsion rate of the source rock can be calculated.

[0076] The specific method is as follows: based on the hydrocarbon generation potential index "(S1) * The relationship between "+S2) / TOC" and depth or organic matter maturity is used to fit a hydrocarbon generation potential curve. Before the source rock matures and reaches the hydrocarbon expulsion threshold, the hydrocarbon generation potential index remains unchanged, which is called the original hydrocarbon generation potential index (GPIo). After the source rock reaches the hydrocarbon expulsion threshold, it continuously expels oil and gas, and the hydrocarbon generation potential index gradually decreases, which is called the residual hydrocarbon generation potential index (GPIr). Since the source rock will suffer organic carbon loss during the evolution process after reaching the hydrocarbon expulsion threshold, the residual hydrocarbon generation potential value needs to be multiplied by the recovery coefficient γ to obtain the recovered residual hydrocarbon generation potential curve. Finally, the original hydrocarbon generation potential index (GPIo) is subtracted from the recovered residual hydrocarbon generation potential index (GPIr) to obtain the hydrocarbon expulsion rate curve, which is used to calculate the hydrocarbon expulsion rate at different depths or organic matter maturity levels, so as to form the corresponding hydrocarbon expulsion rate curve after curve fitting.

[0077] In this way, curves showing the change of hydrocarbon expulsion rate with depth or organic matter maturity can be obtained for each period.

[0078] In this embodiment of the invention, the hydrocarbon expulsion rate under different combinations of time and depth conditions is calculated using the following expression:

[0079]

[0080] q o =GPI o -GPI r ·γ (10)

[0082] GPI o represents the original hydrocarbon generation potential index when the hydrocarbon generation potential index does not exceed the hydrocarbon expulsion threshold, in mg / g; GPI r represents the residual hydrocarbon generation potential index when the hydrocarbon generation potential index reaches and exceeds the hydrocarbon expulsion threshold, in mg / g; γ represents the recovery coefficient; q o represents the hydrocarbon expulsion rate at different depths, in mg / g.

[0083] In the fourth step, the hydrocarbon expulsion intensity at different depth segments for each period is calculated according to the hydrocarbon expulsion rate curve at different periods. In the embodiment of the present application, the depth range in the hydrocarbon expulsion rate curve can be divided into multiple depth segments, and each depth segment involves multiple depth points.

[0084] In the embodiment of the present application, the hydrocarbon expulsion intensity at different depth segments is calculated according to the hydrocarbon expulsion rate curve by using the following expression:

[0085]

[0086] wherein q e represents the hydrocarbon expulsion intensity, in 10 4 t / km 2 ; H o represents the thickness of the source rock, in m; q o (Ro) represents the hydrocarbon expulsion rate corresponding to the organic matter maturity Ro at different depths (points), in mg / g; p s represents the average density of the source rock, in kg / m 3 ; R oe1 , R oe2 respectively represent the lower limit value and the upper limit value of the range of the organic matter maturity (i.e. vitrinite reflectance) corresponding to the depth range of the current depth segment; TOC represents the organic matter abundance, in %.

[0087] Thus, the embodiment of the present application uses the above first step to fourth step to establish the hydrocarbon expulsion model of the source rock and calculate the hydrocarbon expulsion intensity of the source rock at different historical periods and different depths or organic matter maturity according to the hydrocarbon expulsion rate, thickness, organic matter abundance and density of the source rock, so that the hydrocarbon expulsion intensity at corresponding different depth segments for each period is obtained, and then step S130 is entered.

[0088] In step S130, the hydrocarbon expulsion intensity at different depth segments obtained in step S120 is substituted into the dynamic critical equilibrium relationship established in step S110, so that the maximum height of the oil column at different depths is obtained.

[0089] In step S130, the hydrocarbon expulsion intensity data of different depth segments in each period obtained in step S120 is substituted into the dynamic critical balance relationship established in step S110, and the two unknowns (hydrocarbon expulsion intensity and oil column formation height) in the dynamic critical balance relationship are solved by taking the oil generation pressure, oil column gravity, capillary force, fluid pressure and fluid resistance as intermediate variables, so that the maximum height of the oil column formation in different depths is obtained for each period by the calculation results of the intermediate variables.

[0090] Further, in solving the dynamic critical balance relationship, the oil and gas column height parameters in the above expression groups (1) to (6) can be converted into: Thus, the maximum height of the oil column in different depth segments is obtained for each evolution period.

[0091] Example Two

[0092] Next, taking a sandstone reservoir with upper source and lower reservoir in the Bohai Bay Basin in China as an example, the implementation process of the oil column height prediction method described in Example 1 is explained.

[0093] Chezhen Sag is located in the northeast of Jiyang Depression in Bohai Bay Basin, north of Chengzikou Uplift, and south of Wudi-Yihuangzhuang Uplift, which can be divided into slope belt, depression belt and northern steep slope belt from south to north, and is a typical sag with rich oil and gas in the slope belt. Chezixi Depression is a secondary structural unit in Chezhen Sag. The oil source correlation results show that the oil and gas in the fourth member of Shahejie Formation mainly comes from the overlying source rock in the third member of Shahejie Formation, and the source-reservoir relationship is "upper source and lower reservoir". At present, commercial oil flow has been obtained in the fourth member of Shahejie Formation in Paleogene Shahejie Formation, which shows great exploration potential.

[0094] 1. Obtain the force balance relationship, see Figure 2 :

[0095] According to the hydrocarbon generation and expulsion history and distribution range of the source rock in the study area, the time, center-to-edge distance and area experienced are obtained; the test data of oil viscosity and density in the sandstone reservoir under the source rock layer in the study area are collected (see Table 1); the test data of source rock layer density and permeability in the study area are collected (see Table 2); the burial depth and thickness of the source rock layer in the study area are collected (see Figure 3 ); the rock physical characteristic parameters such as wettability angle, interfacial tension and pore throat radius at different burial depths of the sandstone reservoir in the study area are collected (see Table 3); the force balance relationship is established by taking the oil generation pressure and oil column gravity as the power and taking the capillary force, fluid pressure (buoyancy, hydrodynamic force) and fluid attenuation power as the resistance by using the above parameters, and the calculation formula is shown in the above expression (1) to (6) in Example 1.

[0096] Table 1 Physical property parameters of crude oil in the fourth member of Shahejie Formation in Chezhen Sag

[0097]

[0098] Geological parameters of source rock in Es3 of Chezhen Sag

[0099]

[0100] Reservoir petrophysical parameters of Es4 in Chezhen Sag

[0101]

[0102] 2. Obtain the hydrocarbon-generating potential index (S1 * +S2) / TOC:

[0103] The hydrocarbon-generating potential index "(S1 * +S2) / TOC" is obtained for the source rock layer in the study area, and S1 light hydrocarbon is corrected. The correction calculation formula is shown in expression (7) in the above Example 1.

[0104] 3. Obtain the hydrocarbon expulsion rate q o , see Figure 4 :

[0105] The hydrocarbon expulsion rate is calculated according to the "hydrocarbon-generating potential method". The principle of the hydrocarbon-generating potential method is that, in quantitative evaluation of source rock pyrolysis, the sum of soluble hydrocarbon (S1) and cracked hydrocarbon (S2) is usually used to represent the hydrocarbon-generating potential of the source rock. Here, a comprehensive pyrolysis parameter, i.e., the hydrocarbon-generating potential index "(S1 * +S2) / TOC", is used to represent the hydrocarbon-generating potential of the source rock. When the hydrocarbon-generating potential index of the source rock begins to decrease in the geologic history evolution process, it is indicated that hydrocarbons begin to be expelled, and the corresponding burial depth or organic matter maturity represents the expulsion threshold of the source rock. The hydrocarbon expulsion rate of the source rock can be calculated by studying the change of the hydrocarbon-generating potential index on the geologic section. The specific method is as follows: according to the change relationship of the hydrocarbon-generating potential index "(S1 * +S2) / TOC" with depth or organic matter maturity, the hydrocarbon-generating potential curve is fitted. Before the source rock matures and reaches the expulsion threshold, the hydrocarbon-generating potential index does not change, which is called the original hydrocarbon-generating potential index (GPI o ). After the source rock reaches the expulsion threshold, oil and gas are continuously expelled, and the hydrocarbon-generating potential index gradually decreases, which is called the residual hydrocarbon-generating potential index (GPI r ). Since the source rock after reaching the expulsion threshold will cause loss of organic carbon in the evolution process, the residual hydrocarbon-generating potential value needs to be multiplied by a recovery coefficient γ to obtain the recovered residual hydrocarbon-generating potential curve. The expulsion rate curve is obtained by subtracting the original hydrocarbon-generating potential index from the recovered residual hydrocarbon-generating potential index, which is used to calculate the expulsion rate at different depths or organic matter maturity. The recovery coefficient and the expulsion rate calculation formulas are shown in expressions (9) and (10) in the above Example 1.

[0106] 4. Obtain the hydrocarbon expulsion intensity q e , see Figure 5 :

[0107] According to the hydrocarbon expulsion rate of the source rock, the thickness of the source rock, the organic matter abundance and other information, a hydrocarbon expulsion model of the source rock is established and the hydrocarbon expulsion intensity of the source rock under different burial depths or organic matter maturity is calculated. The calculation formula is shown in expression (11) in the above embodiment one.

[0108] 5. Obtain the maximum oil column height h of the source rock under different depths, and the calculation results are shown in Table 4:

[0109] According to the dynamic critical balance relationship formula established according to the oil charging critical condition and the force balance relationship, and converting it into a calculation formula, it is expression (12) in the above embodiment one.

[0110] Table 4. Oil column height formed by source rock under different burial depths in Shasan section of Chezhen sag

[0111]

[0112] Example Three

[0113] Based on the oil column height prediction method of the above embodiment one and embodiment two, the embodiment of the present application further provides a system (also referred to as an "oil column height prediction system") for predicting the maximum height of the oil column in the upper source and lower reservoir type sandstone reservoir. The oil column height prediction system is used to implement the above oil column height prediction method.

[0114] Figure 6 The module block diagram of the system for predicting the maximum height of the oil column in the upper source and lower reservoir type sandstone reservoir of the embodiment of the present application. As shown in Figure 6 , the oil column height prediction system of the embodiment of the present application comprises: a balance relationship formula generation module 61, a hydrocarbon expulsion intensity calculation module 62 and an oil column height prediction module 63.

[0115] Specifically, the balance relationship formula generation module 61 is implemented according to the method described in the above step S110, and is configured to establish a dynamic critical balance relationship formula taking the hydrocarbon expulsion intensity and the oil column formation height as unknown quantities and used to characterize the oil column formation condition and the force balance relationship according to the basic parameters of the source rock layer to be studied; the hydrocarbon expulsion intensity calculation module 62 is implemented according to the method described in the above step S120, and is configured to calculate the hydrocarbon expulsion intensity under different depths according to the pyrolysis experimental parameter data of multiple wells in the source rock layer to be studied; the oil column height prediction module 63 is implemented according to the method described in the above step S130, and is configured to obtain the maximum height of the oil column formed under different depths by substituting the hydrocarbon expulsion intensity under different depths into the dynamic critical balance relationship formula.

[0116] Example Four

[0117] Based on the oil column height prediction method of the above embodiment one and embodiment two, the application provides a computer readable storage medium. The storage medium stores a computer program, and the computer program is executed to run a method for predicting the maximum height of an oil column in a sandstone reservoir with the upper source and lower reservoir. The computer program can run computer instructions, and the computer instructions include computer program codes, which can be in the form of source code, object code, executable files or some intermediate forms.

[0118] The computer readable storage medium can include any entity or device capable of carrying computer program codes, recording medium, U disk, mobile hard disk, magnetic disk, optical disk, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signal, telecommunication signal and software distribution medium.

[0119] It should be noted that the content contained in the computer readable storage medium can be appropriately increased or decreased according to the requirements of legislation and patent practice in the jurisdiction, for example, in some jurisdictions, according to the requirements of legislation and patent practice, the computer readable storage medium does not include electrical carrier signals and telecommunication signals.

[0120] The application discloses a method and system for predicting the maximum height of an oil column in a sandstone reservoir with the upper source and lower reservoir. The method and system comprise: establishing a dynamic balance relationship of the maximum height of the oil column according to the oil and gas charging principle of the upper source and lower reservoir, decomposing the accumulation dynamic (resistance) force into a simple and easy-to-obtain geological parameter expression relationship according to a source rock evolution geological conceptual model, and establishing the change relationship between the maximum height of the oil column and the burial depth of the source rock. The application improves the credibility and accuracy of predicting the maximum height of the oil column in the sandstone reservoir with the upper source and lower reservoir, reduces the risk of oil and gas exploration, has wide applicability for obtaining the maximum height of the oil column formed by the source rock at different depth sections, and can provide a basis for resource evaluation of the upper source and lower reservoir type reservoir.

[0121] The above description is only a preferred embodiment of the application, but the protection scope of the 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 application, which should be covered by the protection scope of the application. Therefore, the protection scope of the application should be subject to the protection scope of the claims.

[0122] In the description of the 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 only for the purpose of facilitating the description of the 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 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.

[0123] In the description of the 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.

[0124] It should be understood that the embodiments disclosed in the present application are not limited to the specific structure, processing steps or materials disclosed herein, but should extend to equivalent alternatives of these features understood by those skilled in the relevant art. It should also be understood that the terms used herein are only for the purpose of describing the specific embodiments and do not mean limitation.

[0125] The phrase "one embodiment" or "an embodiment" appearing in the specification means that the specific feature, structure or characteristic described in connection with the embodiment is included in at least one embodiment of the application. Therefore, the phrase "one embodiment" or "an embodiment" appearing throughout the specification does not necessarily refer to the same embodiment.

[0126] Although the embodiments disclosed in 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 of the present application 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 shall be subject to the scope defined by the appended claims.

Claims

1. A method for predicting the maximum height of an oil column in an upper-generator-lower-reservoir sandstone reservoir, characterized in that, include: Based on the basic parameters of the source rock strata to be studied, a dynamic critical equilibrium relationship is established with hydrocarbon expulsion intensity and oil column formation height as unknowns to characterize the oil column formation conditions and force balance relationship. Based on the pyrolysis experimental parameter data of multiple wells in the source rock strata to be studied, the hydrocarbon expulsion intensity at different depths was calculated. Substituting the hydrocarbon expulsion intensity at different depths into the dynamic critical equilibrium relationship, the maximum height of the oil column at different depths is obtained.

2. The method according to claim 1, characterized in that, Based on seepage theory, and using the sum of oil generation pressurization and oil column gravity as the driving force, and the sum of capillary force, fluid pressure, and fluid resistance as the resistance, the dynamic critical equilibrium relationship is formed through the balance between driving force and resistance. The basic parameters include: the burial depth and thickness of the well in the source rock layer to be studied, the time experienced during the hydrocarbon generation and expulsion period of the source rock, the distance from the hydrocarbon expulsion center to the edge of the source rock, the area of ​​the source rock, the permeability test data of the source rock layer, the viscosity and density test data of crude oil in the sandstone reservoir, and the rock physical characteristic parameters of the sandstone reservoir, including the wetting angle, interfacial tension, and pore throat radius at different burial depths.

3. The method according to claim 2, characterized in that, The dynamic critical equilibrium relationship is expressed by the following formula: P g =ρ o Hg P f =ρ w g(h+H) P d =α·H △P+P g =f+P f +P d Where ΔP represents the oil generation pressurization; S represents the area of ​​the source rock; μ represents the crude oil viscosity; L represents the distance from the hydrocarbon expulsion center to the edge of the source rock; Q i Q represents the amount of hydrocarbons emitted per unit time; e Δt represents the amount of hydrocarbons expelled from the source rock; Δt represents the time elapsed during the critical moments of hydrocarbon generation, expulsion, migration, and accumulation in the source rock; K represents the permeability of the source rock; ρ o q represents the density of crude oil; e P represents the hydrocarbon emission intensity per unit area. g The following parameters are represented: m represents the mass of the oil column; g represents the acceleration due to gravity; H represents the height of the oil column; f represents the capillary force; r represents the reservoir pore throat radius; σ represents the interfacial tension; θ represents the wetting angle; P f ρ represents fluid pressure; w The density of water is represented by h; the depth of the top of the oil / gas column is represented by P. d α represents the fluid resistance during the downward transport of the oil and gas column; α represents the fluid attenuation gradient.

4. The method according to any one of claims 1 to 3, characterized in that, The step of calculating the hydrocarbon expulsion intensity at different depths based on pyrolysis experimental parameter data from multiple wells in the source rock formation under study includes: Core samples from multiple wells in the source rock strata under study were collected at different times and core depths and subjected to pyrolysis experiments to obtain pyrolysis experimental parameter data, including free hydrocarbon content, pyrolysis hydrocarbon content, organic matter abundance and organic matter maturity. The free hydrocarbon content is corrected based on the pyrolysis experimental parameter data; The distribution characteristics of hydrocarbon generation potential index in source rock strata are calculated using corrected pyrolysis experimental parameter data, thereby forming a hydrocarbon expulsion rate curve; Based on the hydrocarbon expulsion rate curve, the hydrocarbon expulsion intensity at different depths is calculated.

5. The method according to claim 4, characterized in that, The step of calculating the distribution characteristics of the hydrocarbon generation potential index in the source rock layer using corrected pyrolysis experimental parameter data, thereby forming the hydrocarbon expulsion rate curve, includes: Based on the corrected pyrolysis experimental parameters, the hydrocarbon generation potential index of the source rock layer at different times and depths was calculated. Based on the hydrocarbon generation potential index at different times and depths, the hydrocarbon expulsion rate at different times and depths is calculated using the following expression: q o =GPI o -GPI r ·γ Among them, GPI o GPI represents the original hydrocarbon generation potential index when the hydrocarbon generation potential index does not exceed the hydrocarbon emission threshold; r γ represents the remaining hydrocarbon generation potential index when the hydrocarbon generation potential index reaches and exceeds the hydrocarbon emission threshold; γ represents the recovery coefficient; q o This indicates the hydrocarbon expulsion rate at different depths.

6. The method according to claim 5, characterized in that, The step of calculating the hydrocarbon expulsion intensity at different depths based on the hydrocarbon expulsion rate curve includes: Where, q e Indicates hydrocarbon expulsion intensity; H o Indicates the thickness of the source rock; q o (Ro) represents the hydrocarbon expulsion rate corresponding to the organic matter maturity Ro at the corresponding depth; ρ s R represents the average density of the source rock; oe1 R oe2 These represent the lower and upper limits of the organic matter maturity range within the current depth segment, respectively; TOC represents organic matter abundance.

7. The method according to any one of claims 4 to 6, characterized in that, The hydrocarbon generation potential index is the ratio of a first value at a corresponding period and depth to the organic matter abundance, where the first value is the sum of the corrected free hydrocarbon content and the pyrolysis hydrocarbon content.

8. The method according to any one of claims 4 to 7, characterized in that, Based on the pyrolysis experimental parameter data, the free hydrocarbon content is corrected using the following expression: Where S1 represents the original free hydrocarbon content, S1 * Ro represents the corrected free hydrocarbon content, and Ro represents the organic matter maturity.

9. A system for predicting the maximum height of an oil column in an upper-generator-lower-reservoir sandstone reservoir, characterized in that, include: The equilibrium relationship generation module is configured to establish a dynamic critical equilibrium relationship based on the basic parameters of the source rock layer to be studied, with hydrocarbon expulsion intensity and oil column formation height as unknowns, and to characterize the oil column formation conditions and force balance relationship. The hydrocarbon expulsion intensity calculation module is configured to calculate the hydrocarbon expulsion intensity at different depths based on the pyrolysis experimental parameter data of multiple wells in the hydrocarbon source rock layer under study. The oil column height prediction module is configured to substitute the hydrocarbon expulsion intensity at different depths into the dynamic critical equilibrium relationship to obtain the maximum oil column height at different depths.

10. A computer-readable storage medium storing computer-executable instructions that, when executed by a processor, implement the steps of the method as described in any one of claims 1 to 9.

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