Condensate gas reservoir fluid component monitoring device and fluid phase change characterization method

Abstract

According to the condensate gas reservoir fluid component monitoring device and the fluid phase state change characterization method provided by the embodiment of the invention, the component monitoring experiment and the material balance calculation are combined to simulate the component change condition of the retained fluid when the pressure of the reservoir is reduced to different pressure stages; pVT sim phase analysis software is combined to carry out state equation simulation calculation to obtain P-T phase diagrams of all pressure stages, the P-T phase diagrams are integrated to obtain a dynamic phase diagram of the depletion development process of the condensate gas reservoir, and the phase change condition of reservoir fluid in the depletion development process of the condensate gas reservoir can be more accurately represented according to the dynamic phase diagram. By means of the method, the phase state change condition of the fluid in the condensate gas reservoir development process can be predicted, and the method has important guiding significance on reasonable design and strategy adjustment of a development scheme.

Description

Technical Field

[0001] The present application relates to the technical field of gas reservoir development, and in particular to a condensate gas reservoir fluid component monitoring device and a fluid phase change characterization method. Background Art

[0002] During the depletion development of condensate gas reservoirs, when the pressure is lower than the dew point pressure, retrograde condensation will occur and the oil phase will separate from the gas phase. Due to the different fluidities of the oil phase and the gas phase, the retained components of the reservoir will continue to change during the production process, so the phase characteristics of the gas reservoir will also change compared to the initial moment.

[0003] The existing method for characterizing the phase state of condensate gas reservoirs is mainly to construct a PT phase diagram. The methods for constructing a PT phase diagram generally include two types: high-temperature and high-pressure PVT phase state experiments and state equation simulation calculation methods. PVT phase state experiments mainly include constant volume depletion experiments, flash separation experiments, and constant mass expansion experiments. Through different experiments, parameters such as dew point pressure, crude oil volume coefficient, gas compression factor, and relative density can be obtained respectively. The determination of the PT phase diagram is mainly achieved through constant mass expansion experiments. Through a series of isothermal constant mass expansion experiments (CCE), the relationship between the volume and pressure of a condensate gas sample of constant mass at a certain temperature can be obtained, thereby determining the dew point or bubble point pressure of the fluid under different conditions. A series of dew points or bubble points are projected on the PT diagram and connected with a smooth curve to obtain the envelope of the fluid. The state equation method is a simpler and more commonly used method. Based on the principle of thermodynamic equilibrium and combined with the state equation for simulation calculation, a complete PT phase diagram including the dew point line and different equal liquid volume lines can be obtained. The establishment of the RK equation in the mid-20th century made the calculation of multi-component fluid properties possible. With the further study of calculation methods, the emergence of the PR equation and the SRK equation has greatly improved the accuracy of gas-liquid phase equilibrium calculations. Currently, mainstream numerical simulation software such as eclipse, CMG, PVT sim, etc. can perform simulation calculations to obtain the PT phase diagram, among which the PR equation and the SRK equation are still the most commonly used.

[0004] At present, most of the research on the phase state of condensate gas reservoirs only stays on the PT phase diagram at the initial moment, and does not take into account the continuous changes in the reservoir retention components as the pressure continues to decrease during the production process. The impact of the changes in the reservoir retention components will have an important impact on the phase state and cannot be ignored. Summary of the invention

[0005] In view of this, the present application provides a condensate gas reservoir fluid component monitoring device and a fluid phase change characterization method, so as to solve the problem that the condensate gas reservoir phase characterization in the prior art does not consider the impact of the continuous pressure reduction on the reservoir retained components, and achieve more accurate characterization of fluid phase changes.

[0006] In a first aspect, an embodiment of the present application provides a device for monitoring fluid components in a condensate gas reservoir, the device comprising:

[0007] The injection pump 1, the fluid intermediate container 2, the core holder 22 and the gas-liquid separator 17 are connected in sequence;

[0008] The fluid intermediate container 2 contains compounded condensate gas and nitrogen, and the fluid in the fluid intermediate container 2 is pressed into the core in the core holder 22 by the injection pump 1;

[0009] The fluid inside the core is separated into oil and gas through the gas-liquid separator 17, and the oil phase component and the gas phase component are collected respectively;

[0010] A back pressure pump 20 and a back pressure valve 16 are provided between the core holder 22 and the gas-liquid separator 17. The back pressure pump 20 is used to provide a constant pressure drop. When the pressure is reduced to a set pressure, the oil phase components and the gas phase components are respectively tested by a chromatograph analyzer 19.

[0011] Preferably, the core holder 22 comprises: a shell 9 , core holder ends 6 and 10 , a sleeve 7 , a confining pressure fluid inlet and outlet 8 , a confining pressure fluid monitoring port 12 , a temperature probe 13 , a confining pressure valve 3 and a thermostatic box 4 .

[0012] Preferably, the shell 9 is used to withstand the confining pressure, the sleeve 7 is placed in the shell 9, the core holder ends 6 and 10 are used to seal the two ends of the shell 9, the port and the shell 9 are threadedly sealed, the sleeve 7 is used to place the experimental core and transmit the confining pressure to the core, the confining pressure liquid inlet and outlet 8 is used to inject and discharge the confining pressure liquid into the shell, the confining pressure liquid monitoring port 12 is used for confining pressure monitoring, the temperature probe 13 is used to monitor the temperature in the sleeve in real time, the confining pressure valve 3 is used to provide confining pressure, and the constant temperature box 4 is used to maintain the temperature environment.

[0013] Preferably, the gas-liquid separator 17 is also connected to a gas flow meter 18, and the gas phase components enter the gas sample bag through the gas flow meter 18 and are collected.

[0014] Preferably, the core holder end 6 is connected to an upstream valve 5 , the upstream valve 5 is connected to a fluid intermediate container 2 through a pipeline, and the fluid intermediate container 2 is connected to an injection pump 1 .

[0015] In a second aspect, the embodiment of the present application further provides a method for characterizing fluid phase change using the monitoring device, the method comprising the following operations:

[0016] Nitrogen is injected into the core in the core holder through an injection pump. When the required pressure is reached, condensate gas is displaced into the core to drive out all the nitrogen. When the saturated core is completed, the amount of material of the component saturated into the core is calculated;

[0017] The back pressure valve is controlled to reduce the pressure. When the pressure drops to the required pressure, the pressure reduction is stopped. The oil phase and gas phase components at the output end are measured and tested by a chromatographic analyzer. The fluid components retained in the core are obtained by material balance calculation.

[0018] The core retained fluid component data at different pressure stages were subjected to phase analysis, and the PT phase diagrams at different pressure stages were obtained by simulation and calculation, and the dynamic phase diagram of the condensate gas reservoir depletion development process was obtained by integration.

[0019] Preferably, the fluid components retained in the core obtained by material balance calculation are as follows:

[0020] When the condensate gas is injected into the core, the pressure is higher than the dew point pressure. The condensate gas in the core is only in the gas phase, which can be calculated by the actual gas state equation:

[0021]

[0022] After the oil phase components are detected by chromatographic analyzer, the total molar mass of the oil phase components can be calculated by the following formula:

[0023]

[0024] Use an electronic balance to weigh the mass m of the collected oil phase a , the gas flow meter measures the collected gas volume V l , no chemical reaction occurs during the experiment, so the amount of the remaining hydrocarbon components in the core can be calculated according to the law of conservation of matter:

[0025]

[0026] The molar ratio of hydrocarbon components in the core is:

[0027]

[0028] Where: x i ,y i The mole percentage of the oil phase and gas phase components measured by the chromatograph, %;

[0029] Z i is the mole percentage of the injected fluid component, %;

[0030] Z ci is the mole percentage of the remaining fluid components in the core, %;

[0031] N is is the total amount of injected fluid, mol;

[0032] P is is the injection pressure, MPa; Vis is the injection volume, ml;

[0033] T is is the injection temperature, K;

[0034] M a is the total molar mass of the produced oil phase, g / mol;

[0035] M i is the molar mass of each component of the output oil phase, g / mol;

[0036] m a is the mass of the produced oil phase, g;

[0037] V l is the volume of the produced gas phase, ml;

[0038] P l is the gas production pressure, atmospheric pressure;

[0039] T l is the gas sampling temperature, standard temperature;

[0040] N c is the amount of total substance of remaining components in the core, mol.

[0041] Preferably, the phase analysis specifically includes: importing data into PVT sim phase analysis software and selecting PR equation for simulation calculation.

[0042] In the embodiments of the present application, the component changes of the retained fluid when the reservoir is depressurized to different pressure stages are simulated by combining component monitoring experiments and material balance calculations, and the state equation simulation calculation is performed in combination with the PVT sim phase analysis software to obtain the PT phase diagram of each pressure stage and integrate it to obtain the dynamic phase diagram of the condensate gas reservoir depletion development process. According to the dynamic phase diagram, the phase changes of the reservoir fluid during the condensate gas reservoir depletion development process can be more accurately characterized. This method can be used to predict the phase changes of the fluid during the condensate gas reservoir development process, which has important guiding significance for the rational design of development plans and strategy adjustments. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0044] Figure 1 A structural diagram of a condensate gas reservoir fluid component monitoring device provided in an embodiment of the present application;

[0045] Figure 2An example diagram of a dynamic phase diagram provided in an embodiment of the present application;

[0046] Figure 3 A dynamic phase diagram of the depletion development process of a condensate gas reservoir provided in an embodiment of the present application;

[0047] In the figure, 1-injection pump, 2-fluid intermediate container, 3-confining pressure valve, 4-constant temperature box, 5-upstream valve, 6-core holder end, 7-sleeve, 8-confining pressure liquid inlet and outlet, 9-shell, 10-core holder end, 11-downstream valve, 12-confining pressure liquid monitoring port, 13-temperature probe, 14-temperature sensor, 15-pressure gauge, 16-back pressure valve, 17-gas-liquid separator, 18-gas flow meter, 19-chromatograph, 20-back pressure pump, 21-monitor. DETAILED DESCRIPTION

[0048] In order to better understand the technical solution of the present application, the embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0049] It should be clear that the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0050] The terms used in the embodiments of the present application are only for the purpose of describing specific embodiments, and are not intended to limit the present application. The singular forms "a", "said" and "the" used in the embodiments of the present application and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings.

[0051] It should be understood that the term "and / or" used in this article is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0052] like Figure 1 As shown, an embodiment of the present invention discloses a device for monitoring fluid components in a condensate gas reservoir, the device comprising:

[0053] The injection pump 1, the fluid intermediate container 2, the core holder 22 and the gas-liquid separator 17 are connected in sequence;

[0054] The fluid intermediate container 2 contains compounded condensate gas and nitrogen, and the fluid in the fluid intermediate container 2 is pressed into the core in the core holder 22 by the injection pump 1;

[0055] The fluid inside the core is separated into oil and gas through the gas-liquid separator 17, and the oil phase component and the gas phase component are collected respectively;

[0056] A back pressure pump 20 and a back pressure valve 16 are provided between the core holder 22 and the gas-liquid separator 17. The back pressure pump 20 is used to provide a constant pressure drop. When the pressure is reduced to a set pressure, the oil phase components and the gas phase components are respectively tested by a chromatograph analyzer 19.

[0057] The embodiment of the present invention uses a long core displacement device to conduct a component monitoring experiment during the depletion development process. Compound condensate gas, and test the initial components through a chromatograph analyzer 18. Determine the basic parameters of the core, calculate the pore volume, and place the core in a core holder. The core holder includes: a shell 9, core holder ends 6 and 10, a sleeve 7, a confining pressure liquid inlet and outlet 8, a confining pressure liquid monitoring port 12, a temperature probe 13, a confining pressure valve 3, and a thermostat 4. The shell 9 is used to withstand the confining pressure required for the experiment, the sleeve 7 is placed in the shell, the core holder ends 6 and 10 are used to seal the two ends of the shell, the port and the shell are threadedly sealed, the sleeve 7 is used to place the experimental core and transmit the confining pressure to the core, the confining pressure liquid inlet and outlet 8 is used to inject and discharge the confining pressure liquid into the shell, the confining pressure liquid monitoring port 12 is used for confining pressure monitoring, the temperature probe 13 is used to monitor the temperature in the sleeve in real time, the confining pressure valve 3 is used to provide confining pressure, and the thermostat 4 is used to maintain the ambient temperature.

[0058] The fluid intermediate container 2 is used to contain the compounded condensate gas and nitrogen, and the core is saturated through the displacement system. The core holder end 6 is connected to the upstream valve 5, and the upstream valve 5 is connected to the fluid intermediate container 2 through a pipeline, and the fluid intermediate container 2 is connected to the injection pump 1. The injection pump 1 provides displacement pressure for the fluid and presses the fluid into the core. During the pressure increase stage, the injection pump 1 injects nitrogen from the fluid intermediate container 2 through the upstream valve 5 and the core holder end 6 into the core. During the saturation stage, the injection pump 1 injects condensate gas from the fluid intermediate container 2 through the upstream valve 5 and the core holder end 6 into the core, and drives out all nitrogen from the core holder end 10. The sampling is analyzed using a chromatograph 19. When the sample is basically consistent with the compound fluid component, the saturation is completed.

[0059] The back pressure pump 20 is regulated to control the back pressure valve 16 to slowly reduce the pressure at a constant pressure drop rate, and the downstream pressure is measured by the downstream pressure gauge 15. The monitor 21 is used to record the temperature and pressure data in real time. The fluid in the core flows into the gas-liquid separator 17 through the pipeline through the back pressure valve, and the oil phase components are measured and collected in the separator, and the gas phase components enter the gas sample bag through the gas flow meter 18 and are collected. When the pressure is reduced to the set pressure, the downstream valve 11 is closed, and the oil phase and gas phase components are tested by the chromatograph analyzer, and then the downstream valve 11 is reopened, and the pressure continues to be reduced to the next pressure point, and the valve is closed again for component analysis.

[0060] The embodiment of the present invention simulates the actual condensate gas reservoir depressurization depletion development and production through a long core depletion experiment, and uses a chromatographic analyzer to test the gas phase and oil phase components at the output end when the pressure is reduced to different pressure stages to obtain component data, thereby providing a data basis for subsequent simulation of fluid component changes in the reservoir.

[0061] The present application also provides a method for characterizing fluid phase change using the condensate gas reservoir fluid component monitoring device, the method comprising the following operations:

[0062] Nitrogen is injected into the core in the core holder through an injection pump. When the required pressure is reached, condensate gas is displaced into the core to drive out all the nitrogen. When the saturated core is completed, the amount of material of the component saturated into the core is calculated;

[0063] The back pressure valve is controlled to reduce the pressure. When the pressure drops to the required pressure, the pressure reduction is stopped. The oil phase and gas phase components at the output end are measured and tested by a chromatographic analyzer. The fluid components retained in the core are obtained by material balance calculation.

[0064] The core retained fluid component data at different pressure stages were subjected to phase analysis, and the PT phase diagrams at different pressure stages were obtained by simulation and calculation, and the dynamic phase diagram of the condensate gas reservoir depletion development process was obtained by integration.

[0065] The composition of the fluid collected at the output end can be obtained through component monitoring experiments. According to the principle of mass conservation, the component retained in the core is the difference between the injection saturation component and the output collection component. The fluid component retained in the core can be obtained through material balance calculation. The specific calculation is as follows:

[0066] When the condensate gas is injected into the core, the pressure is higher than the dew point pressure. The condensate gas in the core is only in the gas phase, which can be calculated by the actual gas state equation:

[0067]

[0068] After the oil phase components are detected by chromatographic analyzer, the total molar mass of the oil phase components can be calculated by the following formula:

[0069]

[0070] The collected oil phase mass ma was weighed by an electronic balance, and the collected gas phase volume Vl was measured by a gas flow meter. No chemical reaction occurred during the experiment, so the amount of the remaining hydrocarbon components in the core can be calculated according to the law of conservation of mass:

[0071]

[0072] The molar ratio of hydrocarbon components in the core is:

[0073]

[0074] Where: x i ,y i The mole percentage of the oil phase and gas phase components measured by the chromatograph, %;

[0075] Z i is the mole percentage of the injected fluid component, %;

[0076] Z ci is the mole percentage of the remaining fluid components in the core, %;

[0077] N is is the total amount of injected fluid, mol;

[0078] P is is the injection pressure, MPa; Vis is the injection volume, ml;

[0079] T is is the injection temperature, K;

[0080] M a is the total molar mass of the produced oil phase, g / mol;

[0081] M i is the molar mass of each component of the output oil phase, g / mol;

[0082] m a is the mass of the produced oil phase, g;

[0083] V l is the volume of the produced gas phase, ml;

[0084] P l is the gas production pressure, atmospheric pressure;

[0085] T l is the gas sampling temperature, standard temperature;

[0086] N c is the amount of total substance of remaining components in the core, mol.

[0087] The molar composition of the fluid components retained in the core can be obtained through the above material balance calculation. The data can be imported into the PVTsim phase analysis software and the PR equation can be selected for simulation calculation to obtain the PT phase diagram when the pressure is reduced to different pressure stages. Multiple PT phase diagrams can be integrated to obtain the following Figure 2 The dynamic phase diagram during the depletion development of a condensate gas reservoir is shown.

[0088] The characteristic of the characterization of fluid phase changes in the depletion development process of the above-mentioned condensate gas reservoir is that the changes in fluid components retained in the core at different pressure stages after depressurization are obtained through component monitoring experiments combined with material balance calculations, and the changes in fluid components in the actual reservoir development process are simulated simply and quickly. The dynamic phase diagram of the development process can then be obtained through simulation calculations using the PVT sim phase analysis software.

[0089] This application simulates the actual condensate gas reservoir depressurization depletion development and production through a long core depletion experiment. The gas phase and oil phase components at the output end when the pressure is reduced to different pressure stages are tested using a chromatograph. According to the principle of mass conservation, the component saturated into the core is equal to the sum of the component collected at the output end and the component retained in the core. Therefore, the components retained in the core at different pressure stages can be obtained through material balance calculation to simulate the fluid component changes in the reservoir. The component data obtained in the experiment are input into the PVT sim software for simulation calculation, and the PT phase diagram and phase state parameters of each stage can be obtained. The simulated PT phase diagram is integrated together to obtain the dynamic phase diagram during the development of the condensate gas reservoir. The dynamic phase diagram can be used to characterize the phase changes when the condensate gas reservoir is depressurized to different pressure stages, and the development plan design can be appropriately adjusted according to the changes in the phase state parameters.

[0090] The embodiment of the present invention monitors the phase change of reservoir fluid during the depletion depressurization development process of the W tight sandstone condensate gas reservoir abroad. The original formation pressure of the target layer is 35.815 MPa, corresponding to the gas reservoir temperature of 93°C. The condensate gas components are compounded according to the actual fluid conditions of the gas reservoir as shown in Table 1, with a gas-oil ratio of 3000m3 / m3 and a dew point pressure of 35.619MPa. The experimental core is a tight sandstone core taken from the gas reservoir, with a permeability of 0.091mD, a porosity of 9.1%, a core length of 89.63mm, and a diameter of 24.47mm.

[0091] Table 1 Composition of sample fluid used in the experiment

[0092]

[0093] Since the experimental pressure is very high and the experimental fluid is mainly gas phase, the device needs to be tested for air tightness before the experiment begins. The fake core is placed in the holder and Figure 1 As shown, connect the devices in sequence and close the downstream valves. Inject nitrogen through the injection pump to apply pressure to 40MPa. After the pressure is basically stable, turn off the injection pump. Observe and record the downstream pressure reading every 5 minutes for one hour. If the downstream pressure reading remains unchanged, it indicates that the airtightness of the entire device is good and the next experimental operation can be carried out.

[0094] After the core is placed in the core holder, the core holder is sealed with a rubber ring and both ends are blocked by the end caps. Figure 1After the device is connected, the temperature and pressure system is established. The clamp, intermediate container, upstream valve, back pressure valve, and gas-liquid separator are placed in a thermostatic box, and the temperature of the thermostatic box is adjusted to the gas reservoir temperature of 93°C. The confining pressure liquid is injected into the shell through the confining pressure liquid injection port of the core clamp shell, and the confining pressure is controlled by a confining pressure pump to maintain the required pressure for the experiment, simulate the pressure of the overburden formation, and adjust the back pressure valve to apply a back pressure of 36MPa.

[0095] When the core is saturated, the nitrogen in the intermediate container is input into the core in the core holder through the injection pump, so that the pressure in the core is gradually increased to 36MPa, which is higher than the dew point pressure of the condensate gas. After the pressure is increased, the condensate gas is driven into the core through the injection pump to drive out all the nitrogen in the core. When the component analysis of the downstream sampling is consistent with the upstream injection component, it is considered that the saturation is complete. For the convenience of the experiment, the back pressure valve is adjusted to increase the core pressure to 40MPa. The amount of the component saturated into the core can be calculated based on the pore volume and the core pressure.

[0096] Then, the pressure reduction was started, and the back pressure valve was controlled to slowly reduce the pressure at a pressure drop rate of 0.1MPa / min. The changes in the pressure indicator at the downstream end were observed. When the pressure dropped to 35MPa, the downstream valve was closed, the pressure reduction was stopped, the oil phase and gas phase components at the output end were measured and tested by the chromatograph, and the fluid components retained in the core at this time were inferred by material balance calculation, and then the downstream valve was opened to continue the experiment. When the pressure dropped to 30MPa and 25MPa respectively, the above operation was repeated. The core retention component data obtained during the experiment are shown in Table 2:

[0097] Table 2 Changes of core retention components

[0098]

[0099] The component data of core retention at different pressure stages obtained during the experimental process were input into the PVT sim phase state analysis software, and the PR state equation was selected for simulation calculation to obtain the PT phase diagrams at different stages. The dynamic phase diagram of the condensate gas reservoir depletion development process was obtained by integration, as shown in the figure. Figure 3 shown.

[0100] The embodiment of the present invention simulates the component changes of the retained fluid when the reservoir is depressurized to different pressure stages by combining component monitoring experiments and material balance calculations, and combines PVT sim phase analysis software to perform state equation simulation calculations to obtain the PT phase diagram of each pressure stage and integrate the dynamic phase diagram of the condensate gas reservoir depletion development process. According to the dynamic phase diagram, the phase changes of the reservoir fluid during the condensate gas reservoir depletion development process can be more accurately characterized. This method can predict the phase changes of the fluid during the condensate gas reservoir development process, which has important guiding significance for the reasonable design of development plans and strategy adjustments.

[0101] The above is only a specific implementation of the present application. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. The protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A condensate gas reservoir fluid component monitoring device, characterized in that: The device comprises: The injection pump (1), the fluid intermediate container (2), the core holder (22) and the gas-liquid separator (17) are connected in sequence; The fluid intermediate container (2) contains compounded condensate gas and nitrogen, and the fluid in the fluid intermediate container (2) is pressed into the core in the core holder (22) by the injection pump (1); The fluid inside the core is separated into oil and gas via a gas-liquid separator (17), and the oil phase component and the gas phase component are collected respectively; A back pressure pump (20) and a back pressure valve (16) are provided between the core holder (22) and the gas-liquid separator (17), and the back pressure pump (20) is used to provide a constant pressure drop; when the pressure is reduced to a set pressure, the oil phase component and the gas phase component are respectively tested by a chromatographic analyzer (19).

2. A condensate gas reservoir fluid component monitoring device according to claim 1, characterized in that: The core holder (22) comprises: a shell (9), core holder ends (6) and (10), a sleeve (7), a confining pressure fluid inlet and outlet (8), a confining pressure fluid monitoring port (12), a temperature probe (13), a confining pressure valve (3) and a constant temperature box (4).

3. A condensate gas reservoir fluid component monitoring device according to claim 2, characterized in that: The shell (9) is used to withstand the confining pressure. The sleeve (7) is placed in the shell (9). The core holder ends (6) and (10) are used to seal the two ends of the shell (9). The port and the shell (9) are threadedly sealed. The sleeve (7) is used to place the experimental core and transmit the confining pressure to the core. The confining pressure liquid inlet and outlet (8) is used to inject and discharge the confining pressure liquid into the shell. The confining pressure liquid monitoring port (12) is used for confining pressure monitoring. The temperature probe (13) is used to monitor the temperature in the sleeve in real time. The confining pressure valve (3) is used to provide the confining pressure. The constant temperature box (4) is used to maintain the temperature environment.

4. The device for monitoring fluid components in a condensate gas reservoir according to claim 1, characterized in that: The gas-liquid separator (17) is also connected to a gas flow meter (18), and the gas phase components enter the gas sample bag through the gas flow meter (18) and are collected.

5. The device for monitoring fluid components in a condensate gas reservoir according to claim 2, characterized in that: The core holder end (6) is connected to an upstream valve (5), the upstream valve (5) is connected to a fluid intermediate container (2) through a pipeline, and the fluid intermediate container (2) is connected to an injection pump (1).

6. A method for characterizing fluid phase change using the monitoring device according to any one of claims 1 to 5, characterized in that: The method comprises the following operations: Nitrogen is injected into the core in the core holder through an injection pump. When the required pressure is reached, condensate gas is displaced into the core to drive out all the nitrogen. When the saturated core is completed, the amount of material of the component saturated into the core is calculated; The back pressure valve is controlled to reduce the pressure. When the pressure drops to the required pressure, the pressure reduction is stopped. The oil phase and gas phase components at the output end are measured and tested by a chromatographic analyzer. The fluid components retained in the core are obtained by material balance calculation. The core retained fluid component data at different pressure stages were subjected to phase analysis, and the PT phase diagrams at different pressure stages were obtained by simulation and calculation, and the dynamic phase diagram of the condensate gas reservoir depletion development process was obtained by integration.

7. The method for characterizing fluid phase change according to claim 6, characterized in that: The fluid components retained in the core obtained by material balance calculation are as follows: When the condensate gas is injected into the core, the pressure is higher than the dew point pressure. The condensate gas in the core is only in the gas phase, which can be calculated by the actual gas state equation: After the oil phase components are detected by chromatographic analyzer, the total molar mass of the oil phase components can be calculated by the following formula: Use an electronic balance to weigh the mass m of the collected oil phase a , the gas flow meter measures the collected gas volume V l , no chemical reaction occurs during the experiment, so the amount of the remaining hydrocarbon components in the core can be calculated according to the law of conservation of matter: The molar ratio of hydrocarbon components in the core is: Where: x i ,y i The mole percentage of the oil phase and gas phase components measured by the chromatograph, %; Z i is the mole percentage of the injected fluid component, %; Z ci is the mole percentage of the remaining fluid components in the core, %; N is is the total amount of injected fluid, mol; P is is the injection pressure, MPa; Vis is the injection volume, ml; T is is the injection temperature, K; M a is the total molar mass of the produced oil phase, g / mol; M i is the molar mass of each component of the output oil phase, g / mol; m a is the mass of the produced oil phase, g; V l is the volume of the produced gas phase, ml; P l is the gas production pressure, atmospheric pressure; T l is the gas sampling temperature, standard temperature; N c is the amount of total substance of remaining components in the core, mol.

8. The method for characterizing fluid phase change according to claim 6, characterized in that: The phase analysis specifically includes: importing the data into PVT sim phase analysis software and selecting the PR equation for simulation calculation.

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