Method for obtaining key parameters in simulation experiment of hydrocarbon source rock heat generation and emission

Abstract

The present application belongs to the technical field of oil and gas exploration and development, and particularly relates to a method for obtaining key hydrocarbon expulsion parameters in a hydrocarbon source rock generation and expulsion simulation experiment, the key hydrocarbon expulsion parameters being specifically critical hydrocarbon expulsion generation and expulsion simulation temperature and average hydrocarbon expulsion pressure; wherein the average hydrocarbon expulsion pressure needs to consider two types of source-reservoir combination modes, i.e., upper reservoir and lower source and upper source and lower reservoir; the present application fills the blank of setting of critical hydrocarbon expulsion conditions in the process of the existing hydrocarbon generation and expulsion simulation experiment. According to geological features such as actual source-reservoir combination relationship and pore wettability, a hydrocarbon expulsion parameter setting method is proposed, so that the hydrocarbon generation and expulsion simulation experiment result can more accurately simulate the hydrocarbon generation and expulsion process of the hydrocarbon source rock in the actual formation, and the experiment result is more instructive.

Description

Technical Field

[0001] This invention belongs to the field of oil and gas exploration and development technology, specifically relating to a method for obtaining key hydrocarbon expulsion parameters in a hydrocarbon source rock heat exhaust simulation experiment. Background Technology

[0002] The hydrocarbon expulsion process of source rocks refers to the process by which hydrocarbons are expelled from the source rocks and enter the reservoir or transport layer, i.e., the initial migration of oil and gas. Accurate characterization of hydrocarbon generation and expulsion features in source rocks is of great significance for evaluating the potential of conventional and unconventional oil and gas resources and studying oil and gas enrichment patterns. Hydrocarbon generation and expulsion physical simulation laboratories are the main means of studying the hydrocarbon generation and expulsion features of source rocks. Based on experimental characteristics, experimental methods are divided into closed-system thermal simulation experiments, open-system thermal simulation experiments, and semi-open-system hydrocarbon generation and expulsion thermal simulation experiments.

[0003] Compared to closed-system and open-system thermal simulation experiments, the advantage of semi-open-system hydrocarbon generation and expulsion simulation experiments lies in their ability to simulate not only the hydrocarbon generation process of source rocks under certain heating rates and hydrocarbon generation and expulsion thermal simulation temperatures, but also the simultaneous simulation of the hydrocarbon expulsion process. From the perspective of hydrocarbon generation chemical reactions, the timing and amount of hydrocarbon product expulsion can affect the hydrocarbon generation characteristics of source rocks. Therefore, how to set the hydrocarbon expulsion parameters from source rocks becomes the key to accurately simulating the hydrocarbon generation and expulsion process of source rocks.

[0004] At present, there is a lack of effective means to set the key parameters for hydrocarbon generation and emission in semi-open system hydrocarbon generation and emission simulation experiments.

[0005] In the process of simulating hydrocarbon generation and expulsion in shale, some scholars did not set key parameters such as hydrocarbon expulsion pressure. They kept the hydrocarbon expulsion pipe connected to the bottom of the high-pressure reactor open to expel hydrocarbons, or opened the hydrocarbon expulsion valve to start expelling hydrocarbons after the high-pressure reactor reached the preset simulation temperature and was kept at a constant temperature for a period of time.

[0006] Some scholars have set hydrocarbon expulsion pressures, but lack reasonable theoretical basis. For example, they set the hydrocarbon expulsion initiation pressure as the product of the formation pressure benchmark value and the maximum pressure coefficient, and the hydrocarbon expulsion closure pressure as the product of the formation pressure benchmark value and the minimum pressure coefficient. Alternatively, they define the hydrocarbon expulsion pressure as the sum of effective stress, hydrostatic pressure, and the slight yield pressure overcoming clay. In reality, hydrocarbon expulsion can only occur when the hydrocarbon expulsion dynamics in the source rock are sufficient to overcome the capillary pressure difference between the source rock and the reservoir.

[0007] Due to the lack of reasonable criteria for setting key hydrocarbon expulsion parameters, the current semi-open system cannot accurately simulate the hydrocarbon expulsion process, resulting in certain deviations in the understanding of the hydrocarbon generation and expulsion characteristics of source rocks in geological history. Summary of the Invention

[0008] This invention aims to address the above-mentioned problems by comprehensively considering the influence of factors such as the coupling effect of hydrocarbon generation and expulsion in the hydrocarbon generation and expulsion mechanism, the source-storage combination mode, and the difference in wettability of the source-storage on the hydrocarbon expulsion resistance, and proposes a method for obtaining key hydrocarbon expulsion parameters in the source rock generation and expulsion heat simulation experiment.

[0009] The technical solution of this invention is as follows: A method for obtaining key hydrocarbon expulsion parameters in a source rock generation and expulsion heat simulation experiment, characterized by the following: the key hydrocarbon expulsion parameter is specifically the critical hydrocarbon generation and expulsion heat simulation temperature. and mean hydrocarbon expulsion pressure ; Among them, the critical hydrocarbon generation and emission thermal simulation temperature The specific solution process is as follows: (2) (1) In the formula: The vitrinite reflectance corresponding to the hydrocarbon expulsion threshold, % The hydrocarbon emission threshold is expressed in °C. It also includes mean hydrocarbon expulsion pressure Mean hydrocarbon expulsion pressure In the hydrocarbon expulsion thermal simulation experiment, the average hydrocarbon expulsion resistance that the hydrocarbons generated from the source rock need to overcome to be expelled from the source rock and enter the reservoir is simulated.

[0010] Based on the locational relationship between the source rock and the reservoir, the average hydrocarbon expulsion pressure in the hydrocarbon generation and expulsion thermal simulation experiment needs to consider two types of source-reservoir combination modes: upper reservoir and lower source, and upper source and lower reservoir. Simultaneously, since most minerals on the micropore walls of the reservoir rock are hydrophilic, and the diagenetic minerals in the source rock are hydrophilic while kerogen is oleophilic, the wettability of the micropores between the source rock and the reservoir needs to be considered. This means that hydrocarbons may be expelled from the oleophilic kerogen micropores of the source rock and enter the hydrophilic mineral micropores of the reservoir, and hydrocarbons may be expelled from the hydrophilic mineral micropores of the source rock and enter the hydrophilic mineral micropores of the reservoir. Taking all these factors into account, the average hydrocarbon expulsion pressure... The following four scenarios need to be considered, and corresponding calculation methods need to be established for each.

[0011] (1) The source-reservoir combination mode is upper reservoir and lower source. When hydrocarbons enter the reservoir from the hydrophilic mineral micropores of the source rock, the average hydrocarbon expulsion pressure is Capillary force within the pores of the source rock Capillary forces within reservoir rock pores The difference between the hydrostatic pressure and the hydrostatic pressure Summation; that is (3) Among them, hydrostatic pressure The specific solution process is as follows: (4) In the formula: Density of formation water, kg / m³ 3 ; The acceleration due to gravity is taken as 9.8 m / s². 2 ; The depth of the formation is in meters (m). Among them, the capillary force in the source rock pores The specific solution process is as follows: According to the following formula (5); (6); (7); (8) The calculation yielded: (9) In the formula: The oil-water interfacial tension within the capillary of the source rock, N / m; The wetting angle at the oil-water interface of the hydrocarbon source rock is given in degrees. The average pore radius of the source rock is given in meters. The permeability of the source rock, specifically regarding of function, cm 2 ; Porosity of source rocks, dimensionless; The porosity of the source rock sample is measured, dimensionless (1). The function fitting parameters for the burial depth of the source rock sample are dimensionless; The burial depth of the source rock sample is in meters. Among them, the capillary force within the reservoir rock pores Represented as: (10) in, (11); (12); (13); Therefore, we get: (14) In summary, mean hydrocarbon emission pressure The specific calculation formula is as follows: (15) In the formula: The oil-water interfacial tension within the reservoir capillary, in N / m; The wetting angle at the reservoir oil-water interface is given in degrees. The average pore radius of the reservoir rock is given in meters (m). For reservoir rock permeability, specifically regarding of function, cm 2 ; Porosity of reservoir rock, dimensionless; The porosity of the reservoir rock sample is measured, dimensionless. The function fitting parameters for the burial depth of the reservoir rock sample are dimensionless; The depth of the reservoir rock sample is in meters (m).

[0012] (2) The source-reservoir combination mode is upper reservoir and lower source. When hydrocarbons enter the reservoir's hydrophilic mineral micropores from the oleophilic kerogen micropores of the source rock, the average hydrocarbon expulsion pressure is Capillary force within the pores of the source rock Capillary forces within reservoir rock pores With hydrostatic pressure The sum; that is: (16) Specifically: (17).

[0013] (3) The source-reservoir combination mode is upper source and lower reservoir. When hydrocarbons enter the reservoir from the hydrophilic mineral micropores of the source rock, the average hydrocarbon expulsion pressure is Buoyancy of hydrocarbons ;Right now: (18); (19) Specifically: (20) In the formula: Hydrocarbon density, kg / m³ 3 ; The height of the oil column is in meters (m).

[0014] (4) The source-reservoir combination mode is upper source and lower reservoir. When hydrocarbons enter the hydrophilic mineral micropores of the reservoir from the oleophilic kerogen micropores of the source rock, the average hydrocarbon expulsion pressure is Buoyancy of hydrocarbons Capillary forces within the pores of source rocks Capillary forces within reservoir rock pores The sum; that is: (twenty one) Specifically: (twenty two).

[0015] Wherein, the hydrocarbon emission threshold The hydrocarbon generation potential was obtained through the hydrocarbon generation potential method; specifically, it was based on the thermal hydrocarbon yield of source rock samples from the target layer in the study area. Thermal cracking hydrocarbon yield Total organic carbon content Calculate the hydrocarbon generation potential index Hydrocarbon generation potential index The x-axis represents the peak temperature of rock pyrolysis. Plot the source rock samples of the target layer in the study area on the ordinate. A scatter plot of the data is created by drawing the outer envelope of the scatter points on the plot. The outer envelope curve changes with the peak temperature of the rock pyrolysis. When the temperature decreases with the increase of the value, the corresponding rock pyrolysis peak temperature is... This refers to the hydrocarbon expulsion threshold value of the source rock samples from the target layer in the study area. .

[0016] The technical advantages of this invention are as follows: This invention fills the gap in the setting of critical conditions for hydrocarbon generation and expulsion in existing hydrocarbon generation and expulsion simulation experiments. Based on actual source-reservoir bonding relationships, pore wettability, and other geological characteristics, a method for setting hydrocarbon expulsion parameters is proposed, enabling the results of hydrocarbon generation and expulsion thermal simulation experiments to more accurately simulate the hydrocarbon generation and expulsion processes of source rocks in actual strata, and making the experimental results more instructive. Attached Figure Description

[0017] Figure 1 It is a source rock of the Chang 7 hydrocarbon generation in the Ordos Basin. Scatter plot of data. Detailed Implementation

[0018] Example – A method for obtaining key hydrocarbon expulsion parameters in a hydrocarbon source rock heat expulsion simulation experiment, the method is as follows: Step 1: Draw the source rock samples of the target layer in the study area. A scatter plot of the data was used to determine the hydrocarbon emission threshold for the corresponding sample. The vitrinite reflectance corresponding to the hydrocarbon expulsion threshold is determined by equation (1). The critical hydrocarbon generation and emission thermal simulation temperature is determined by equation (2). ; Step 2: Determine the thermal simulation temperature for hydrocarbon generation and expulsion. Calculate the thermal simulation temperature of each hydrocarbon generation and expulsion. Corresponding mean hydrocarbon expulsion pressure The specific process is as follows: Data from source rock samples of the target layer in the study area were fitted to obtain the source rock porosity. Burial depth of source rock samples and source rock permeability Relationship; Data from reservoir rock samples of the target layer in the study area were fitted to obtain the reservoir rock porosity. Burial depth of reservoir rock samples and reservoir rock permeability ; Furthermore, based on the positional relationship between the source rock and the reservoir, and the wettability of the source rock and the reservoir micropores, the average hydrocarbon expulsion pressure under various conditions was calculated. .

[0019] Specific experimental case: Setting key parameters for hydrocarbon expulsion during a thermal simulation experiment of hydrocarbon generation and expulsion in the Chang 7 section shale formation of the Yanchang exploration area in the Ordos Basin.

[0020] 1. Critical hydrocarbon generation and emission thermal simulation temperature Calculation Mapping source rock samples of the target layer in the study area Data scatter plot as follows Figure 1 The hydrocarbon expulsion threshold value of the Chang 7 member source rock in the Yanchang exploration area of ​​the Ordos Basin was determined. The vitrinite reflectance corresponding to the hydrocarbon expulsion threshold value is determined by equation (1) at 435℃. The value is 0.66. The critical hydrocarbon generation and emission thermal simulation temperature is determined by equation (2). It is 367℃.

[0021] 2. Mean hydrocarbon expulsion pressure Calculation Assuming the hydrocarbon generation and expulsion thermal simulation temperature in the experiment The temperatures are set to: 314℃, 327℃, 344℃, 370℃, 390℃, 413℃, 429℃, 437℃, 441℃, 446℃, 453℃, 473℃, 490℃, 510℃, 550℃, and 590℃. These are the simulated temperatures for hydrocarbon generation and expulsion below the critical hydrocarbon expulsion temperature. (367℃) There is no need to set the average hydrocarbon expulsion pressure; therefore, when the hydrocarbon generation and expulsion thermal simulation temperature is in the hydrocarbon generation and expulsion thermal simulation experiment... For temperatures of 370℃, 390℃, 413℃, 429℃, 437℃, 441℃, 446℃, 453℃, 473℃, 490℃, 510℃, 550℃, and 590℃, corresponding average hydrocarbon expulsion pressures need to be set. Obtain the thermal simulation temperature of each hydrocarbon generation and expulsion. Corresponding vitrinite reflectance The burial depth of the source rock samples corresponding to the above vitrinite reflectance was obtained using basin simulation methods. ; Table 1 Vitrin reflectance of source rock samples and the burial depth of source rock samples ; Porosity of source rock samples from the target layer Burial depth of source rock samples Hydrocarbon source rock permeability The relationships are as follows: , ; reservoir rock porosity Burial depth of reservoir rock samples reservoir rock permeability The relationships are as follows: , ; Assuming the oil-water interfacial tension within the capillary of the source rock and the interfacial tension of oil and water in reservoir capillaries All are 3×10 -2 N / m, reservoir oil-water interface wetting angle The wetting angle at the oil-water interface of the oleophilic source rock is 30°. 100°; Wetting angle at the oil-water interface of hydrophilic source rocks. 30°; hydrocarbon density 850 kg / m 3 Formation water density 1000 kg / m 3 Oil column height 10 m; mean hydrocarbon expulsion pressure under various conditions The calculation results are shown below.

[0022] (1) The source-reservoir combination mode is upper reservoir and lower source. When hydrocarbons enter the reservoir from the hydrophilic mineral micropores of the source rock, the average hydrocarbon expulsion pressure is The calculation results are shown in Table 2. Table 2 Average hydrocarbon expulsion pressure The calculation results (Case 1) .

[0023] (2) The source-reservoir combination mode is upper reservoir and lower source. When hydrocarbons enter the hydrophilic mineral micropores of the reservoir from the oleophilic kerogen micropores of the source rock, Table 3: Table 3 Average Hydrocarbon Exhaust Pressure The calculation results (case 2) .

[0024] (3) The source-reservoir combination mode is upper source and lower reservoir. When hydrocarbons enter the reservoir from the hydrophilic mineral micropores of the source rock, the average hydrocarbon expulsion pressure is The calculation results are shown in Table 4: Table 4 Average Hydrocarbon Exhaust Pressure The calculation results (case 3) .

[0025] (4) The source-reservoir combination mode is upper source and lower reservoir. When hydrocarbons enter the hydrophilic mineral micropores of the reservoir from the oleophilic kerogen micropores of the source rock, the average hydrocarbon expulsion pressure is The calculation results are shown in Table 5: Table 5 Average hydrocarbon expulsion pressure The calculation results (case 4) .

Claims

1. A method for obtaining key hydrocarbon expulsion parameters in a hydrocarbon source rock heat expulsion simulation experiment, characterized in that, The method is as follows: the key hydrocarbon expulsion parameter is specifically the critical hydrocarbon expulsion generation and expulsion thermal simulation temperature. and mean hydrocarbon expulsion pressure ; Among them, the critical hydrocarbon generation and emission thermal simulation temperature The specific solution process is as follows: (2) (1) In the formula: The vitrinite reflectance corresponding to the hydrocarbon expulsion threshold, % The hydrocarbon emission threshold is expressed in °C. This also includes the thermal simulation temperature of hydrocarbon generation and emission below the critical hydrocarbon expulsion level. No need to set mean hydrocarbon pressure ; Among them, average hydrocarbon expulsion pressure The specific solution process is as follows: When the source-storage combination method is upper storage and lower source, The average hydrocarbon expulsion pressure when hydrocarbons enter the reservoir from the micropores of hydrophilic minerals in the source rock. Capillary force within the pores of the source rock Capillary forces within reservoir rock pores The difference between the hydrostatic pressure and the hydrostatic pressure Summation; When hydrocarbons enter the hydrophilic mineral micropores of the reservoir from the oleophilic micropores of the source rock (kerogen), the average hydrocarbon expulsion pressure is... Capillary force within the pores of the source rock Capillary forces within reservoir rock pores With hydrostatic pressure sum; When the source-reservoir combination is upper source and lower reservoir, the average hydrocarbon expulsion pressure is as follows: [The text abruptly ends here, likely due to an incomplete sentence or a formatting error.] Buoyancy of hydrocarbons ; When hydrocarbons enter the hydrophilic mineral micropores of the reservoir from the oleophilic micropores of the source rock (kerogen), the average hydrocarbon expulsion pressure is... Buoyancy of hydrocarbons Capillary forces within the pores of source rocks Capillary forces within reservoir rock pores sum.

2. The method for obtaining key hydrocarbon expulsion parameters in the source rock expulsion heat simulation experiment according to claim 1, characterized in that, When the source-storage combination method is upper storage and lower source, When the hydrocarbons enter the reservoir's hydrophilic mineral micropores from the source rock's hydrophilic mineral micropores, the average hydrocarbon expulsion pressure is... The specific solution process is as follows: (15) In the formula: Density of formation water, kg / m³ 3 ; The acceleration due to gravity is taken as 9.8 m / s². 2 ; The depth of the formation is in meters (m). The oil-water interfacial tension within the capillary of the source rock, N / m; The wetting angle at the oil-water interface of the hydrocarbon source rock, in degrees; The porosity of the source rock sample is measured, dimensionless (1). The function fitting parameters for the burial depth of the source rock sample are dimensionless; The burial depth of the source rock sample is in meters. The oil-water interfacial tension within the reservoir capillary, in N / m; The wetting angle at the reservoir oil-water interface is given in degrees. The porosity of the reservoir rock sample is measured, dimensionless. The function fitting parameters for the burial depth of the reservoir rock sample are dimensionless; The burial depth of the reservoir rock sample is in meters. In the formula, and Both represent functions.

3. The method for obtaining key hydrocarbon expulsion parameters in the hydrocarbon source rock expulsion heat simulation experiment according to claim 1, characterized in that, When the source-storage combination method is upper storage and lower source, When hydrocarbons enter the hydrophilic mineral micropores of the reservoir from the oleophilic micropores of the source rock (kerogen), the average hydrocarbon expulsion pressure is... The specific solution process is as follows: (17) In the formula: Density of formation water, kg / m³ 3 ; The acceleration due to gravity is taken as 9.8 m / s². 2 ; The depth of the formation is in meters (m). The oil-water interfacial tension within the capillary of the source rock, N / m; The wetting angle at the oil-water interface of the hydrocarbon source rock, in degrees; The porosity of the source rock sample is measured, dimensionless (1). The function fitting parameters for the burial depth of the source rock sample are dimensionless; The burial depth of the source rock sample is in meters. The oil-water interfacial tension within the reservoir capillary, in N / m; The wetting angle at the reservoir oil-water interface is given in degrees. The porosity of the reservoir rock sample is measured, dimensionless. The function fitting parameters for the burial depth of the reservoir rock sample are dimensionless; The burial depth of the reservoir rock sample is in meters. In the formula, and Both represent functions.

4. The method for obtaining key hydrocarbon expulsion parameters in the source rock heat expulsion simulation experiment according to claim 1, characterized in that, When the source-storage combination method is upper source and lower storage, When the hydrocarbons enter the reservoir's hydrophilic mineral micropores from the source rock's hydrophilic mineral micropores, the average hydrocarbon expulsion pressure is... The specific solution process is as follows: (18) (19) In the formula: Density of formation water, kg / m³ 3 ; Hydrocarbon density, kg / m³ 3 ; The acceleration due to gravity is taken as 9.8 m / s². 2 ; The height of the oil column is in meters (m).

5. The method for obtaining key hydrocarbon expulsion parameters in the hydrocarbon source rock expulsion heat simulation experiment according to claim 1, characterized in that, When the source-storage combination method is upper source and lower storage, When hydrocarbons enter the hydrophilic mineral micropores of the reservoir from the oleophilic micropores of the source rock (kerogen), the average hydrocarbon expulsion pressure is... The specific solution process is as follows: (22) In the formula: Density of formation water, kg / m³ 3 ; Hydrocarbon density, kg / m³ 3 ; The acceleration due to gravity is taken as 9.8 m / s². 2 ; The height of the oil column is in meters (m). The oil-water interfacial tension within the capillary of the source rock, N / m; The wetting angle at the oil-water interface of the hydrocarbon source rock, in degrees; The porosity of the source rock sample is measured, dimensionless (1). The function fitting parameters for the burial depth of the source rock sample are dimensionless; The burial depth of the source rock sample is in meters. The oil-water interfacial tension within the reservoir capillary, in N / m; The wetting angle at the reservoir oil-water interface is given in degrees. The porosity of the reservoir rock sample is measured, dimensionless. The function fitting parameters for the burial depth of the reservoir rock sample are dimensionless; The burial depth of the reservoir rock sample is in meters. In the formula, and Both represent functions.

6. The method for obtaining key hydrocarbon expulsion parameters in the hydrocarbon source rock expulsion heat simulation experiment according to claim 1, characterized in that, The hydrostatic pressure The specific solution process is as follows: (4)。 7. The method for obtaining key hydrocarbon expulsion parameters in the hydrocarbon source rock expulsion heat simulation experiment according to claim 1, characterized in that, The capillary force within the source rock pores The specific solution process is as follows: (5)； (6)； (7)； (8)； In the formula: The oil-water interfacial tension within the capillary of the source rock, N / m; The wetting angle at the oil-water interface of the hydrocarbon source rock, in degrees; The average pore radius of the source rock is given in meters. The permeability of the source rock, specifically regarding... of function, cm 2 ; Porosity of source rocks, dimensionless; The porosity of the source rock sample is measured, dimensionless (1). The function fitting parameters for the burial depth of the source rock sample are dimensionless; The depth of the source rock sample is in meters.

8. The method for obtaining key hydrocarbon expulsion parameters in the hydrocarbon source rock heat expulsion simulation experiment according to claim 1, characterized in that, Capillary force within the reservoir rock channels The specific solution process is as follows: (10)； (11)； (12)； (13)； In the formula: The oil-water interfacial tension within the reservoir capillary, in N / m; The wetting angle at the reservoir oil-water interface is given in degrees. The average pore radius of the reservoir rock is given in meters (m). For reservoir rock permeability, specifically regarding of function, cm 2 ; Porosity of reservoir rock, dimensionless; The porosity of the reservoir rock sample is measured, dimensionless. The function fitting parameters for the burial depth of the reservoir rock sample are dimensionless; The depth of the reservoir rock sample is in meters (m).

9. The method for obtaining key hydrocarbon expulsion parameters in the hydrocarbon source rock expulsion heat simulation experiment according to claim 1, characterized in that, The hydrocarbon emission threshold The hydrocarbon generation potential method was used; specifically, it was obtained by utilizing the thermal hydrocarbon yield of source rock samples from the target layer in the study area. Thermal cracking hydrocarbon yield Total organic carbon content Calculating the hydrocarbon generation potential index ; Hydrocarbon generation potential index The x-axis represents the peak temperature of rock pyrolysis. Plot the source rock samples of the target layer in the study area on the ordinate. A scatter plot of data is created by drawing the outer envelope of the data points on the plot. The outer envelope curve changes with the peak temperature of rock pyrolysis. When the temperature decreases with the increase of the value, the corresponding rock pyrolysis peak temperature is... This refers to the hydrocarbon expulsion threshold value of the source rock samples from the target layer in the study area. .

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