Method for determining oil and gas filling time

Abstract

The invention relates to the technical field of oil exploration and development, in particular to a method for determining oil and gas filling time, which comprises the following steps: identifying the occurrence and the period of a hydrocarbon inclusion, and identifying a brine inclusion associated with the hydrocarbon inclusion in the same period; the uniform temperature of the hydrocarbon inclusion and the uniform temperature of the brine inclusion in the same period are obtained through experiments, and the actually measured gas-liquid ratio of the hydrocarbon inclusion is obtained; performing iterative calculation according to the uniform temperature of the hydrocarbon inclusion and the uniform temperature of the brine inclusion in the same period to determine the actual capture temperature of the hydrocarbon inclusion; and comparing the actual capture temperature of the hydrocarbon inclusion with the corresponding single well burial history diagram or profile burial history diagram, and determining the oil and gas filling time. The method overcomes the defect that in the prior art, due to the fact that the oil and gas filling time is determined by replacing the capture temperature of the hydrocarbon inclusion with the uniform temperature of the same-period saline water inclusion associated with the hydrocarbon inclusion, deviation exists in the oil and gas filling time.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of oil exploration and development, and particularly relates to a method for determining oil and gas charging time. BACKGROUND

[0002] In the process of oil exploration and development, determining oil and gas charging time is a very key step. The oil and gas charging time refers to the time of the process that oil and gas migrate from source rock to reservoir and finally gather to form an oil and gas reservoir. Determining this time is crucial for successfully finding and developing oil and gas reservoirs, and can predict the existence of oil and gas reservoirs, evaluate the scale of oil and gas reservoirs and reduce exploration risks.

[0003] The existing determination of oil and gas charging time is mostly through the homogenization temperature of the contemporaneous salt water inclusion corresponding to the hydrocarbon inclusion as the capture temperature of the hydrocarbon inclusion to determine the charging time of the oil and gas. However, the homogenization temperature of the contemporaneous salt water inclusion is not equal to the capture temperature of the hydrocarbon inclusion, so that the charging time of the oil and gas is deviated. SUMMARY

[0004] The present application aims to overcome the deficiency in the prior art that the homogenization temperature of the contemporaneous salt water inclusion corresponding to the hydrocarbon inclusion is used as the capture temperature of the hydrocarbon inclusion to determine the charging time of the oil and gas, and the charging time of the oil and gas is deviated, and to provide a method for determining the charging time of the oil and gas.

[0005] In order to achieve the above-mentioned purpose, the technical scheme adopted by the present application is as follows:

[0006] The present application provides a method for determining the charging time of oil and gas, comprising the following steps:

[0007] S1, identifying the occurrence and period of the hydrocarbon inclusion, and identifying the contemporaneous salt water inclusion corresponding to the hydrocarbon inclusion according to the occurrence and period of the hydrocarbon inclusion;

[0008] S2, experimentally obtaining the homogenization temperature of the hydrocarbon inclusion and the homogenization temperature of the contemporaneous salt water inclusion, and experimentally obtaining the measured gas-liquid ratio of the hydrocarbon inclusion;

[0009] S3, iteratively calculating the theoretical gas-liquid ratio of the hydrocarbon inclusion according to the homogenization temperature of the hydrocarbon inclusion and the homogenization temperature of the contemporaneous salt water inclusion, and when the difference between the theoretical gas-liquid ratio of the n+1th iteration and the theoretical gas-liquid ratio of the nth iteration is less than the convergence accuracy of the measured gas-liquid ratio, the theoretical capture temperature corresponding to the n+1th iteration is the actual capture temperature of the hydrocarbon inclusion;

[0010] S4, comparing the actual capture temperature of the hydrocarbon inclusion obtained in step S3 with the corresponding single well burial history graph or profile burial history graph, and finding the time T corresponding to the actual capture temperature, and the time T is the oil and gas charging time.

[0011] Contemporaneous saline inclusions refer to fluid inclusions with high salt concentration that coexist with hydrocarbon inclusions or other types of inclusions in geological materials. Homogenization temperature of an inclusion refers to the temperature at which the fluid in the inclusion changes from two or more phases to a single phase under specific conditions. Occurrence of an inclusion refers to the distribution, morphology, size, quantity and other related characteristics of the inclusion in a geological environment. Burial history chart is a geological chart used to show the changes of burial depth and temperature of a region or a specific stratigraphic unit over time.

[0012] The method first determines the occurrence and period of the hydrocarbon inclusions, then identifies the contemporaneous saline inclusions coexisting with the hydrocarbon inclusions, and then respectively determines the homogenization temperature of the hydrocarbon inclusions and the measured gas-liquid ratio and the homogenization temperature of the contemporaneous saline inclusions. The theoretical gas-liquid ratio of the hydrocarbon inclusions is iteratively calculated according to the homogenization temperature of the hydrocarbon inclusions and the homogenization temperature of the contemporaneous saline inclusions. When the difference between the theoretical gas-liquid ratio of the n+1th iteration and the theoretical gas-liquid ratio of the nth iteration is less than the convergence precision, the theoretical trapping temperature corresponding to the n+1th iteration is the actual trapping temperature of the hydrocarbon inclusions. Then the actual trapping temperature of the hydrocarbon inclusions and the corresponding single-well burial history chart or profile burial history chart are compared to determine the charging time of the oil and gas. Compared with the prior art which directly takes the homogenization temperature of the contemporaneous saline inclusions coexisting with the hydrocarbon inclusions as the trapping temperature and then determines the charging time of the oil and gas, the method calculates the theoretical trapping temperature of the hydrocarbon inclusions by the homogenization temperature of the hydrocarbon inclusions and the homogenization temperature of the contemporaneous saline inclusions and then determines the charging time of the oil and gas, which is beneficial to reduce the error in determining the charging time of the oil and gas, thereby reducing the risk encountered in subsequent oil exploitation as much as possible.

[0013] Preferably, the homogenization temperature of the hydrocarbon inclusions and the homogenization temperature of the contemporaneous saline inclusions are obtained by respectively heating the hydrocarbon inclusions and the contemporaneous saline inclusions in step S2.

[0014] Because the homogenization temperature is the temperature at which the fluid in the inclusion changes from two or more phases to a single phase, heating the inclusion causes the disappearance of the gas bubbles inside the inclusion, and only liquid-phase substances are left inside the inclusion. By heating, the homogenization temperature of the hydrocarbon inclusions and the homogenization temperature of the contemporaneous saline inclusions are determined by respectively observing the hydrocarbon inclusions and the contemporaneous saline inclusions.

[0015] Preferably, during the heating process, the gas bubbles inside the hydrocarbon inclusions or the contemporaneous saline inclusions are observed, and when the gas bubbles inside the hydrocarbon inclusions or the contemporaneous saline inclusions disappear, the corresponding temperature is the homogenization temperature of the hydrocarbon inclusions or the contemporaneous saline inclusions.

[0016] When determining the homogenization temperature of the hydrocarbon inclusion, the gas bubbles inside the hydrocarbon inclusion are observed, and the temperature at which the gas bubbles inside the hydrocarbon inclusion disappear is the homogenization temperature of the hydrocarbon inclusion; when determining the homogenization temperature of the contemporaneous saltwater inclusion, the gas bubbles inside the contemporaneous saltwater inclusion are observed, and the temperature at which the gas bubbles inside the contemporaneous saltwater inclusion disappear is the homogenization temperature of the contemporaneous saltwater inclusion.

[0017] Preferably, when the gas bubbles inside the hydrocarbon inclusion or the contemporaneous saltwater inclusion are close to disappearing, the heating rate is reduced until the hydrocarbon inclusion or the contemporaneous saltwater inclusion is completely frozen, and then the temperature is reduced by 2-5°C to determine the homogenization temperature of the hydrocarbon inclusion or the contemporaneous saltwater inclusion.

[0018] Preferably, the step S2 of determining the homogenization temperature of the contemporaneous saltwater inclusion and obtaining the measured gas-liquid ratio of the hydrocarbon inclusion further comprises obtaining the freezing point of the contemporaneous saltwater inclusion, and the salinity of the contemporaneous saltwater inclusion is obtained by converting the freezing point of the contemporaneous saltwater inclusion.

[0019] Sometimes, the hydrocarbon inclusion and the contemporaneous saltwater inclusion cannot be separated by the occurrence and the homogenization temperature, so the contemporaneous saltwater inclusion is separated by measuring the salinity of the contemporaneous saltwater inclusion, and whether the contemporaneous saltwater inclusion is consistent with the result of the step S1 is also reviewed.

[0020] Preferably, the contemporaneous saltwater inclusion is heated at a preset rate, and the temperature at which the ice crystals inside the contemporaneous saltwater inclusion disappear is the freezing point of the contemporaneous saltwater inclusion.

[0021] Preferably, when the ice crystals inside the contemporaneous saltwater inclusion are close to disappearing, the temperature is reduced to promote the growth of the ice crystals and move the gas bubbles inside the contemporaneous saltwater inclusion, and then the temperature is increased again until the ice crystals inside the contemporaneous saltwater inclusion disappear and the freezing point of the contemporaneous saltwater inclusion is recorded.

[0022] When measuring the freezing point of the contemporaneous saltwater inclusion, the temperature is first increased, then decreased, and finally increased again, because in the initial heating process, volatile components (such as CO2) in the inclusion may be precipitated and form bubbles, and the existence of these bubbles will affect the subsequent measurement of the freezing point. By first heating, these components can be released, and subsequent cooling can cause them to dissolve in the liquid phase again, reducing the interference with the measurement of the freezing point. And by setting such a heating sequence, the initial heating can also help to relieve the stress existing in the inclusion, thereby reducing the error that may occur when measuring the freezing point, and improving the accuracy of the freezing point measurement.

[0023] Preferably, the iterative calculation in step S3 is calculated according to the following formula:

[0024] P (n+1) =P (n) +ΔP

[0025] T (n+1) = T (n) + ΔT

[0026]

[0027]

[0028]

[0029] wherein P (n+1) is the theoretical internal pressure of the hydrocarbon inclusion at the (n+1)th iteration calculation, ΔP is the theoretical pressure value increased by the (n+1)th iteration calculation compared with the nth iteration calculation, ΔP = 0 at the initialization iteration calculation, T (n+1) is the theoretical trapping temperature of the hydrocarbon inclusion at the (n+1)th iteration calculation, ΔT is the theoretical temperature value increased by the (n+1)th iteration calculation compared with the nth iteration calculation, ΔT = 0 at the initialization iteration calculation, is the theoretical gas phase volume inside the hydrocarbon inclusion at the (n+1)th iteration calculation, is the theoretical liquid phase volume inside the hydrocarbon inclusion at the (n+1)th iteration calculation, V is the total volume of the hydrocarbon inclusion, which can be measured, GLR (n+1) is the theoretical gas-liquid ratio of the hydrocarbon inclusion at the (n+1)th iteration calculation.

[0030] Preferably, when GLR (n+1) - GLR (n) < ε, the iteration calculation is ended, and T (n+1) is taken as the actual trapping temperature of the hydrocarbon inclusion, wherein GLR (n) is the theoretical gas-liquid ratio of the hydrocarbon inclusion at the nth calculation, and ε is the convergence accuracy of the measured gas-liquid ratio.

[0031] ε is valued according to the actual situation, when the difference between the theoretical gas-liquid ratios of two iteration calculations is less than the convergence accuracy of the measured gas-liquid ratio, it is considered that the theoretical gas-liquid ratio is consistent with the measured gas-liquid ratio, and the theoretical trapping temperature fitted at this time is the actual trapping temperature of the hydrocarbon inclusion.

[0032] Preferably, in step S1, the inclusion sample is placed in the transmission light and fluorescence mode for positioning observation, and the period corresponding to the inclusion is judged according to the color tone of the light emitted by different inclusions.

[0033] Different periods of hydrocarbon inclusions will emit different color tones of fluorescence due to the difference in components and maturity, and the uncle judges the period corresponding to the inclusion through the color tone of the light emitted by the inclusion.

[0034] In summary, due to the adoption of the above technical scheme, the present application has the following beneficial effects:

[0035] 1. A method for determining the oil and gas charging time, the method comprising the following steps: determining the occurrence and period of the hydrocarbon inclusion, identifying the coeval brine inclusion associated with the hydrocarbon inclusion, determining the homogenization temperature of the hydrocarbon inclusion and the measured gas-liquid ratio of the hydrocarbon inclusion and the homogenization temperature of the coeval brine inclusion, performing iterative calculation of the theoretical gas-liquid ratio of the hydrocarbon inclusion according to the homogenization temperature of the hydrocarbon inclusion and the homogenization temperature of the coeval brine inclusion, when the difference between the theoretical gas-liquid ratio of the n+1th iteration and the theoretical gas-liquid ratio of the nth iteration is less than the convergence precision, the theoretical trapping temperature corresponding to the n+1th iteration is the actual trapping temperature of the hydrocarbon inclusion, and then comparing the actual trapping temperature of the hydrocarbon inclusion with the corresponding single well burial history graph or profile burial history graph to determine the oil and gas charging time. BRIEF DESCRIPTION OF DRAWINGS

[0036] Figure 1 is a step diagram of the method for determining the oil and gas charging time;

[0037] Figure 2 is a schematic diagram of the dolomite sample in the inclusion sample;

[0038] Figure 3 is a schematic diagram of the hydrocarbon inclusion in the dolomite vein body;

[0039] Figure 4 is a schematic diagram of the coeval brine inclusion associated with the hydrocarbon inclusion in the dolomite vein body;

[0040] Figure 5 is a schematic diagram of the isochore of the coeval trapping of the hydrocarbon inclusion and the coeval brine inclusion;

[0041] Figure 6 is a structural belt burial history and thermal evolution history graph of the corresponding region. DETAILED DESCRIPTION

[0042] The application will be described in further detail below with reference to the embodiments. However, it should be understood that the scope of the above subject matter of the application is not limited to the following embodiments, and any technology achieved based on the content of the application falls within the scope of the application.

[0043] In the description of the embodiments of the application, the terms indicating the orientation or positional relationship of "up", "down", "left", "right", "center", "inner", "outer", and the like, are expressed based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product / device / apparatus of the application is usually placed. These terms of orientation or positional relationship are only for the convenience of describing the application scheme or simplifying the description in the embodiments, and for the convenience of the technical personnel to quickly understand the scheme, and do not indicate or imply that a specific device / component / element must have a specific orientation or be constructed and operated in a specific positional relationship, and therefore cannot be understood as a limitation on the application.

[0044] In addition, if the terms "horizontal", "vertical", "suspension", "parallel", and the like appear, it does not mean that the corresponding device / component / element must be absolutely horizontal or vertical or suspended or parallel, but can be slightly inclined or deviated. For example, "horizontal" only means that its direction is more horizontal relative to "vertical", and does not mean that the structure must be completely horizontal, but can be slightly inclined. Alternatively, it can be simplified to understand that the corresponding device / component / element is arranged in the direction of "horizontal", "vertical", "suspension", "parallel", etc., and can have an error / deviation of ±10% relative to the corresponding direction, more preferably an error / deviation of ±8% or less, more preferably an error / deviation of ±6% or less, more preferably an error / deviation of ±5% or less, and more preferably an error / deviation of ±4% or less. As long as the corresponding device / component / element is within the error / deviation range, it can still achieve its role in the scheme of the application.

[0045] In addition, the terms "first", "second", "third", and the like appearing in the terms are only used to distinguish the description of the same or similar components, and should not be understood as emphasizing or implying the relative importance of the specific components.

[0046] In addition, in the description of the embodiments of the application, "several", "a plurality of", and "several" represent at least 2. It can be 2, 3, 4, 5, 6, 7, 8, 9, etc. in any case, and can even be more than 9.

[0047] Furthermore, in the description of the technical solutions of the present application, unless otherwise explicitly specified / limited / limited, the terms "set", "install", "connect", "connect", "provide", "lay", "arrange" appearing in the description should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrally connected, which can be welding, riveting, bolting, screwing, etc. The connection means commonly used in the art. Such connection can be mechanical connection, electrical connection or communication connection; it can be directly connected or indirectly connected through an intermediate medium; it can be the communication between two elements.

[0048] Embodiment 1

[0049] As Figure 1 shown, the method for determining the oil and gas filling time adopted in the present embodiment comprises the following steps:

[0050] S1, select a rock sample developed with vein or cave filled with calcite, dolomite and other minerals to grind into a thin section (usually 30pm) as an inclusion sample, and place the inclusion sample which may contain hydrocarbon inclusions under transmission light and fluorescence mode for positioning observation, contain n1 period of hydrocarbon inclusions, identify the occurrence and period of hydrocarbon inclusions combined with petrography and sedimentary microfacies, and determine the same period of salt water inclusions associated with hydrocarbon inclusions, wherein i is the period of geology.

[0051] S2, experimental data acquisition:

[0052] S201, obtaining the homogenization temperature of hydrocarbon inclusions:

[0053] Put the prepared sample into a cold and hot table, select an appropriate rate to warm up the hydrocarbon inclusions, and observe the bubbles in the hydrocarbon inclusions during the warming up process. When the bubbles in the hydrocarbon inclusions disappear, the corresponding temperature is the homogenization temperature of the hydrocarbon inclusions. Because the temperature of the hydrocarbon inclusions is generally lower than that of the same period of the same period of the salt water inclusions, and the freezing point of the hydrocarbon inclusions is different, the homogenization temperature of the hydrocarbon inclusions is tested first. The selection of the warming rate is determined according to the actual situation.

[0054] In actual operation, different warming rates can be controlled in the early stage of temperature measurement according to the range of homogenization temperature. When the bubbles in the hydrocarbon inclusions are close to disappearing (the common phenomenon is that the bubbles gradually become smaller and the bubbles start to move at high frequency), the warming rate is reduced until the hydrocarbon inclusions are completely frozen, or the observation is paused, or the homogenization temperature of the hydrocarbon inclusions is determined by reducing 2-5℃; In this process, the focal length of the microscope also needs to be adjusted up and down, and the observation range should be controlled within the focal plane range of the upper and lower walls of the hydrocarbon inclusions to avoid experimental misreading caused by observation omission.

[0055] S202, obtaining the homogenization temperature of the same period of salt water inclusions:

[0056] Put the prepared sample into the cooling and heating table, select the appropriate rate to warm the same period of saline inclusion, in the process of warming, observe the bubble inside the same period of saline inclusion, when the bubble inside the same period of saline inclusion disappears, the corresponding temperature is the uniform temperature of the same period of saline inclusion. The selection of the rate of warming is determined according to the actual situation.

[0057] In actual operation, the uniform temperature range can be controlled in the early stage of temperature measurement, when the bubble inside the same period of saline inclusion is close to disappear (common phenomenon is that the bubble gradually becomes smaller, and the bubble starts to move at high frequency), the warming rate is reduced until the same period of saline inclusion is completely frozen, or the observation is paused, or the uniform temperature of the same period of saline inclusion can be determined by reducing 2-5℃; In this process, the focal length of the microscope also needs to be adjusted up and down, and the observation range is within the focal plane range of the upper and lower walls of the same period of saline inclusion, so as to avoid experimental misreading caused by observation omission.

[0058] S203, obtaining the freezing point of the same period of saline inclusion

[0059] Warming the same period of saline inclusion at a predetermined rate, when the ice crystals inside the same period of saline inclusion disappear, the corresponding temperature is the freezing point of the same period of saline inclusion, and the freezing point of the same period of saline inclusion is converted to the salinity of the same period of saline inclusion by the following formula:

[0060] Wt(NaCl) = -1.76958D - 0.042384D 2 -0.00052778D 3

[0061] Wherein, Wt(NaCl) is the percentage concentration of NaCl solution, that is, the salinity; D is the freezing point of the same period of saline inclusion.

[0062] In actual operation, the uniform temperature of the same period of saline inclusion is measured to start rewarming, and in the rewarming process, the behavior of ice crystals in the inclusion is observed. When the last ice crystal is about to melt, the ice crystal is quickly cooled to grow again and push the bubble away from the original position; continue to warm, record the temperature when the ice crystal melts and finally completely melts. If the ice crystal grows again after cooling and the bubble does not move, the temperature at this time is the freezing point temperature of the fluid inclusion.

[0063] S204, obtaining the measured gas-liquid ratio of the hydrocarbon inclusion:

[0064] The measured gas-liquid ratio of the hydrocarbon inclusion is obtained by three-dimensional scanning of a single hydrocarbon inclusion of the hydrocarbon inclusion by using a laser confocal microscope.

[0065] S3, iteratively calculate the theoretical gas-liquid ratio of the hydrocarbon inclusion according to the homogenization temperature of the hydrocarbon inclusion and the homogenization temperature of the coeval brine inclusion according to the following formula:

[0066] P (n+1) = P (n) + ΔP

[0067] T (n+1) = T (n) + ΔT

[0068]

[0069]

[0070]

[0071] wherein P (n+1) is the theoretical internal pressure of the hydrocarbon inclusion in the n+1th iteration calculation, ΔP is the theoretical pressure value increased in the n+1th iteration calculation compared with the nth iteration calculation, ΔP = 0 in the initialization iteration calculation, T (n+1) is the theoretical trapping temperature of the hydrocarbon inclusion in the n+1th iteration calculation, ΔT is the theoretical temperature value increased in the n+1th iteration calculation compared with the nth iteration calculation, ΔT = 0 in the initialization iteration calculation, is the theoretical gas phase volume inside the hydrocarbon inclusion in the n+1th iteration calculation, is the theoretical liquid phase volume inside the hydrocarbon inclusion in the n+1th iteration calculation, V is the total volume of the hydrocarbon inclusion, which can be measured, GLR (n+1) is the theoretical gas-liquid ratio of the hydrocarbon inclusion in the n+1th iteration calculation.

[0072] when GLR (n+1) - GLR (n) < ε, end the iteration calculation, and take T (n+1) as the actual trapping temperature of the hydrocarbon inclusion, wherein GLR (n) is the theoretical gas-liquid ratio of the hydrocarbon inclusion in the nth calculation, and ε is the convergence accuracy of the measured gas-liquid ratio. In actual situations, the iteration calculation will also be ended when the upper limit of the number of iteration calculations is reached.

[0073] In actual use, the iteration calculation can need more complex models and algorithms, including but not limited to PVT (pressure-volume-temperature) relationship, phase behavior model, thermodynamic equation, etc. Therefore, in actual application, professional software or programming language can also be used to realize these calculations.

[0074] S4, comparing the actual trapping temperature of the hydrocarbon inclusions obtained in step S3 with the corresponding single-well burial history graph or profile burial history graph, finding the time T corresponding to the actual trapping temperature, and the time T is the oil and gas charging time.

[0075] Further, in step S1, under the excitation of the ultraviolet module in the fluorescence mode, different periods of hydrocarbon inclusions will emit different color tones of fluorescence due to the differences in components and maturity, such as brown-yellow fluorescence for low maturity, medium-green fluorescence for medium maturity, and blue-white fluorescence for high maturity, so that the period of the hydrocarbon inclusion can be determined. When searching for the associated contemporaneous saltwater inclusions, the contemporaneous saltwater inclusions with similar occurrence to the hydrocarbon inclusions and a temperature about 15-25℃ higher than that of the hydrocarbon inclusions are the associated contemporaneous saltwater inclusions.

[0076] Example 2

[0077] Based on Example 1, taking the Devonian Guanwushan Formation strata of Guangyuan Kuangshanliang section in front of Longmenshan in Sichuan Basin as an example.

[0078] Step 1: Select the field section rock sample in which vein bodies develop, grind the fluid inclusion test sample, and place it under transmission light and fluorescence mode for positioning observation, identify the occurrence and period of the hydrocarbon inclusions emitting different fluorescence, find the associated contemporaneous saltwater inclusion group, and position and mark them, as shown in Figs. 2 and 3. Figure 2 Figure 3 Figure 4

[0079] Step 2: Place the prepared thin section into a cold-hot stage, select an appropriate temperature rising / dropping rate to respectively heat the hydrocarbon inclusions of each period and the associated contemporaneous saltwater inclusion group, and measure the homogenization temperatures of the hydrocarbon inclusions and the associated contemporaneous saltwater inclusions, wherein the homogenization temperatures of the hydrocarbon inclusions are 84.3℃, 85.8℃, 92.3℃, 94.6℃, and 95.2℃ respectively, and the homogenization temperatures of the associated contemporaneous saltwater inclusions are 106.7℃, 108.6℃, 110.5℃, 112.5℃, and 114.7℃ respectively, as shown in Figs. 4 and 5. Figure 3 Figure 4

[0080] Step 3: After obtaining the homogenization temperatures of the five groups of hydrocarbon inclusions and the associated contemporaneous saltwater inclusions, the precise gas-liquid ratio of the hydrocarbon inclusions is obtained by three-dimensional scanning with a laser confocal microscope. The gas-liquid ratio of the hydrocarbon inclusions is obtained by iterative calculation using the PVT simulation software for calculating the physical properties of oil, and is matched with the experimental measurement value, so as to determine the trapping temperature of the inclusions. Through simulation calculation, the trapping temperature of the inclusions of the Devonian Guanwushan Formation in northwest Sichuan is 122.3℃-128.5℃, as shown in Fig. 6. Figure 5

[0081] ​​​​​​Step 4: reading out the time vertical to the temperature interval of 122.3-128.5℃ on the burial history graph of the Devonian Guanwushan Formation in the northwest of Sichuan, which is J1 (175-200Ma), i.e. the early Jurassic (J1) is the oil and gas charging time, as shown in Figure 6

[0082] The above merely describes the preferred embodiments of the present application, but not intended to limit the present application, any modification, equivalent replacement and improvement within the spirit and principle of the present application shall be included in the protection scope of the present application.​

Claims

1. A method of determining hydrocarbon charge time, characterized by, Comprising the following steps: S1, identifying the occurrence and period of hydrocarbon inclusions, and identifying the same period brine inclusions associated with the hydrocarbon inclusions according to the occurrence and period of the hydrocarbon inclusions; S2, obtaining the homogenization temperature of the hydrocarbon inclusions and the homogenization temperature of the same period brine inclusions respectively through experiments, and obtaining the measured gas-liquid ratio of the hydrocarbon inclusions through experiments; S3, iteratively calculating the theoretical gas-liquid ratio of the hydrocarbon inclusions according to the homogenization temperature of the hydrocarbon inclusions and the homogenization temperature of the same period brine inclusions, and when the difference between the theoretical gas-liquid ratio calculated in the m+1th iteration and the theoretical gas-liquid ratio calculated in the mth iteration is less than the convergence accuracy of the measured gas-liquid ratio, the theoretical trapping temperature corresponding to the m+1th iteration calculation is the actual trapping temperature of the hydrocarbon inclusions; S4, comparing the actual trapping temperature of the hydrocarbon inclusions obtained in step S3 with the corresponding single well burial history graph or profile burial history graph to find the time T corresponding to the actual trapping temperature, and the time T is the oil and gas charging time.

2. The method of determining hydrocarbon charge time according to claim 1, wherein, In step S2, the homogenization temperature of the hydrocarbon inclusions and the homogenization temperature of the same period brine inclusions are obtained by respectively heating the hydrocarbon inclusions and the same period brine inclusions.

3. The method of determining hydrocarbon charge time according to claim 2, wherein, During the heating process, the gas bubbles inside the hydrocarbon inclusions or the same period brine inclusions are observed, and when the gas bubbles inside the hydrocarbon inclusions or the same period brine inclusions disappear, the corresponding temperature is the homogenization temperature of the hydrocarbon inclusions or the same period brine inclusions.

4. The method of determining hydrocarbon charge time according to claim 3, wherein, When the gas bubbles inside the hydrocarbon inclusions or the same period brine inclusions are close to disappearing, the heating rate is reduced until the hydrocarbon inclusions or the same period brine inclusions are completely frozen, and then the temperature is reduced by 2-5℃ to determine the homogenization temperature of the hydrocarbon inclusions or the same period brine inclusions.

5. The method of determining the oil and gas charge time according to any one of claims 1-4, characterized in that, Between determining the homogenization temperature of the same period brine inclusions and obtaining the measured gas-liquid ratio of the hydrocarbon inclusions in step S2, the freezing point of the same period brine inclusions is also obtained, and the salinity of the same period brine inclusions is converted from the freezing point of the same period brine inclusions.

6. The method of determining hydrocarbon charge time according to claim 5, wherein, The same period brine inclusions are heated at a predetermined rate, and when the ice crystals inside the same period brine inclusions disappear, the corresponding temperature is the freezing point of the same period brine inclusions.

7. The method of determining hydrocarbon charge time according to claim 6, wherein, When the ice crystals inside the same period brine inclusions are close to disappearing, the temperature is reduced to promote the growth of the ice crystals and move the gas bubbles inside the same period brine inclusions, and then the temperature is increased again until the ice crystals inside the same period brine inclusions disappear and the freezing point of the same period brine inclusions is recorded.

8. The method of determining the oil and gas charge time according to any one of claims 1-4, characterized in that, In step S3, the iterative calculation is calculated according to the following formula: P (n+1) = P (n) + ΔP T (n+1) = T (n) + ΔT V g (n+1) =V g (P (n+1) ,T (n+1) ) V L (n+1) = V - V g (n+1) GLR (n+1) = V g (n+1) / V L (n+1) wherein P (n+1) is the theoretical internal pressure of the hydrocarbon inclusion at the n+1th iteration, ΔP is the theoretical pressure value added in the n+1th iteration compared to the nth iteration, ΔP = 0 at the initialization of the iterative calculation, T (n+1) is the theoretical trapping temperature of the hydrocarbon inclusion at the n+1th iteration, ΔT is the theoretical temperature value added in the n+1th iteration compared to the nth iteration, ΔT = 0 at the initialization of the iterative calculation, V g (n+1) is the theoretical gas phase volume inside the hydrocarbon inclusion at the n+1th iteration, V L (n+1) is the theoretical liquid phase volume inside the hydrocarbon inclusion at the n+1th iteration, V is the total volume of the hydrocarbon inclusion, which can be measured, GLR (n+1) is the theoretical gas-liquid ratio of the hydrocarbon inclusion at the n+1th iteration.

9. The method of determining hydrocarbon charge time according to claim 8, wherein, When GLR (n+1) -GLR (n) <ε, the iterative calculation is ended, and T (n+1) is the actual trapping temperature of the hydrocarbon inclusion, where GLR (n) is the theoretical gas-liquid ratio of the hydrocarbon inclusion at the nth calculation, and ε is the convergence accuracy of the measured gas-liquid ratio.

10. The method of determining the oil and gas charge time according to any one of claims 1-4, characterized in that, In step S1, the inclusion sample is placed in the transmission light and fluorescence mode for positioning observation, and the period corresponding to the inclusion is judged according to the color tone of the light emitted by different inclusions.

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