Method for testing adsorption and desorption capabilities of condensate gas

Abstract

The invention discloses a condensate gas adsorption and desorption capability testing method, which comprises the following steps: screening reservoir rock broken samples, loading the samples into a sample cylinder, injecting methane to make the gas pressure of the sample cylinder higher than the condensate gas dew point pressure, injecting mixed gas into a reference cylinder to reach the set pressure, communicating the sample cylinder with the reference cylinder to prepare condensate gas, and testing the adsorption and desorption capability of the condensate gas. Then injecting condensate gas, increasing the pressure to reservoir pressure from a set pressure gradient, measuring the adsorption amount of the rock to the condensate gas at different pressure points above the dew point pressure, and then reducing the pressure in a gradient manner to measure the desorption amount of the rock to the condensate gas at different pressure points. Based on the constant mass expansion experiment result of the condensate gas, the measurement error of the reverse condensate oil volume on the gas desorption amount is eliminated, and the adsorption / desorption capacity of the rock sample on the condensate gas is evaluated. According to the scheme, the adsorption / desorption amount of the condensate gas can be accurately measured, and reserve calculation and efficient development of the condensate gas reservoir are facilitated.

Description

Technical Field

[0001] The present invention relates to the field of petroleum and natural gas engineering technology, and in particular to a method for evaluating the volume change of reservoir gas adsorption / desorption caused by pressure change during engineering operations such as oil reservoir development and production enhancement, and specifically to a test method for evaluating the adsorption and desorption capacity of condensate gas. Background Art

[0002] During the exploration and development of oil reservoirs, as the gas extraction leads to a decrease in reservoir pressure, the phase state of condensate gas will also change, producing condensate oil and the phenomenon of retrograde condensation. Condensate gas is a mixed gas of various hydrocarbons. Conventional volumetric and gravimetric methods cannot measure the adsorption / desorption capacity of condensate gas due to the retrograde condensation phenomenon. These methods fail to effectively obtain the adsorption / desorption volume of condensate gas at different pressures, making it difficult to provide a theoretical basis for gas injection development and prevention of retrograde condensation damage, which restricts the accuracy of reserve evaluation and economic development of tight rock gas reservoirs.

[0003] The current test methods for the adsorption of condensate gas all use a gas that does not undergo phase change to replace the condensate gas for measurement. The competitive adsorption of different gas components and the influence of condensate oil production on the desorption capacity of condensate gas are not considered, and the adsorption / desorption capacity of the real condensate gas cannot be measured. In order to determine the adsorption and desorption of condensate gas in condensate gas reservoirs under the phenomenon of retrograde condensation, evaluate the reserves of condensate gas and provide a basis for optimizing development plans, the present invention makes up for the shortcomings of the volumetric method and the gravimetric method, eliminates the error caused by condensate oil production, and establishes an evaluation method that can measure the adsorption and desorption capacity of condensate gas. Summary of the invention

[0004] In view of the above problems, the object of the present invention is to provide a method for testing the adsorption and desorption capacity of condensate gas. The technical solution adopted by the present invention is as follows: A method for testing the adsorption and desorption capacity of condensate gas, which uses a condensate gas adsorption and desorption test device to perform a test experiment, characterized in that the condensate gas adsorption and desorption test device includes a booster pump, a methane gas cylinder connected to the booster pump, a first helium gas cylinder, a mixed gas cylinder, a condensate gas cylinder, a second helium gas cylinder, a first valve connected to the outlet section of the methane gas cylinder, a reference cylinder A connected to the first valve, a first pressure sensor arranged on the reference cylinder A, a second valve connected to the outlet of the reference cylinder A, a third valve connected to the outlet of the mixed gas cylinder, a reference cylinder B connected to the third valve, a second pressure sensor arranged on the reference cylinder B, a fourth valve connected to the outlet of the reference cylinder B, a fifth valve connected to the outlet section of the condensate gas cylinder, a reference cylinder C connected to the fifth valve, and a pressure sensor arranged on the reference cylinder B. A third pressure sensor on the reference cylinder C, a sixth valve connected to the outlet of the reference cylinder C, a sample cylinder connected to the outlets of the second valve, the fourth valve, and the sixth valve, a temperature sensor arranged on the sample cylinder, a seventh valve connected to the outlet of the sample cylinder, a fourth pressure sensor connected to the seventh valve, a vacuum pump connected to the outlet of the seventh valve, a back pressure valve connected to the outlet of the sample cylinder, a gas collecting device connected to the outlet of the back pressure valve, a fifth pressure sensor arranged on the gas collecting device, and a computer control system respectively connected to the first pressure sensor, the second pressure sensor, the third pressure sensor, the fourth pressure sensor, the fifth pressure sensor and the temperature sensor, a rock cutting sample to be tested is placed in the sample cylinder, and the reference cylinder A, the reference cylinder B, the reference cylinder C and the sample cylinder are arranged in a constant temperature pool; The method for testing the adsorption and desorption capacity of condensate gas comprises the following steps: S1. After washing the oil and salt from the downhole rock samples and drying them, the rock samples with a particle size range of 60-80 mesh are screened out by sieving method; S2. Keep all valves closed and load the crushed rock into the sample cylinder; open the second valve, the fourth valve, the sixth valve and the seventh valve, connect the reference cylinder A, the reference cylinder B, the reference cylinder C and the sample cylinder, and evacuate the system with a vacuum pump; after the evacuation is completed, close the second valve, the sixth valve and the seventh valve, open the first valve, use the first helium bottle to introduce helium into the system, adjust the pressure of the reference cylinder A to the set pressure through the booster pump, and collect the pressure value after the air pressure in the reference cylinder A stabilizes; close the first valve, open the second valve, connect the reference cylinder A, the reference cylinder B and the sample cylinder, and after the pressure is balanced, collect the final pressure after the balance, and calibrate the free space volume of the first system V 1; Then evacuate the system and close all valves; open the fifth valve, introduce helium into the system through the second helium bottle, adjust the pressure of reference cylinder C to the set pressure through the booster pump, and collect the pressure value after the pressure in reference cylinder C stabilizes; connect reference cylinder C and sample, and after the pressure is balanced, collect the final pressure after balance, and then calculate the free space volume of the second system V 2 ; Place reference cylinder A, reference cylinder B, reference cylinder C and sample cylinder in a constant temperature pool to simulate the reservoir temperature of the rock sample; S3, open the first valve, close the second valve, and use a methane gas cylinder to pass methane into reference cylinder A until the set pressure is P A Then close the first valve, open the second valve, connect the reference cylinder A and the sample cylinder, wait for the fourth pressure sensor to indicate a stable reading; open the third valve, and introduce the mixed gas into the reference cylinder B through the mixed gas cylinder to the set pressure P B ; Close the third valve, open the fourth valve, connect the reference cylinder B with the reference cylinder A and the sample cylinder, wait for the pressure of the fourth pressure sensor of the sample cylinder to stabilize for 12 hours, and record the time and pressure P x and temperature, complete the initial pressure point P x Adsorption capacity test of samples; Initial point P x The adsorption amount of condensate gas is calculated by the following formula: When the pressure is increased by the gradient, the pressure point P i The adsorption amount was calculated by the following formula: V x is the adsorption amount of condensate gas, cm 3 / g; V A , V B , V C and V The volumes of reference cylinder A, reference cylinder B, reference cylinder C and sample cylinder, cm 3 ; P A and P B are the set pressures of reference cylinder A and reference cylinder B, MPa; V 1 , V 2is the measured free space volume of the first and second systems, cm 3 ; S4. Close the second valve and the fourth valve, open the fifth valve, pump condensate gas into the reference cylinder C through the condensate gas bottle, and record the pressure of the reference cylinder C as P c ; Close the fifth valve, open the sixth valve, connect the reference cylinder C and the sample cylinder, so that the pressure in the sample cylinder reaches the pressure point to be measured; P x Start to increase the pressure gradually from the initial point. After stabilizing at each pressure point for 12 hours, record the time, temperature and pressure. P i , the condensate gas adsorption capacity of the test sample at different pressure points; S5. When the pressure point rises to the reservoir pressure, start to reduce the pressure gradually and measure the desorption amount of condensate gas at different pressure points; keep all valves closed, then open the sixth valve to connect the reference cylinder C and the sample cylinder, control the pressure in the sample cylinder by adjusting the back pressure of the back pressure valve, and collect the gas volume at the outlet of the back pressure valve; set at least 10 pressure points from the reservoir pressure gradient to atmospheric pressure as back pressure in turn, and record the time and pressure after each test pressure is stable for 12 hours. P 1 and temperature T ; Pressure point during desorption P 1 The desorption amount of condensate gas is calculated by the following formula: V JX is the amount of desorbed gas, cm 3 ; P max is the end point pressure of the adsorption experiment, MPa; V max is the end point pressure of the adsorption experiment P max Adsorption capacity under 3 ; P out is the pressure of the gas collection device, MPa; V out is the volume of the gas collection device, cm 3 ; N is the percentage of condensate measured in the constant mass expansion experiment, %; P 1 The pressure at each measuring point, MPa.

[0005] Compared with the prior art, the present invention has the following beneficial effects: (1) The present invention is applicable to some condensate gas reservoirs with multi-component gases in the reservoirs, and solves the problem that only the adsorption / desorption capacity of a single gas in the rock can be tested separately and the competitive adsorption between the multi-component gases is not considered, thus making it impossible to truly measure the adsorption / desorption amount of the condensate gas.

[0006] (2) The present invention can be used to measure the gas adsorption / desorption capacity of dense rocks in the presence of retrograde condensation, thereby solving the problem that the adsorption / desorption amount of rocks cannot be measured due to the generation of condensate oil due to phase changes. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 It is a structural schematic diagram of the present invention.

[0008] In the above drawings, the component names corresponding to the reference numerals are as follows: 1. Booster pump; 2. Methane cylinder; 3. First valve; 4. First pressure sensor; 5. Second valve; 6. Reference cylinder A; 7. Mixed gas cylinder; 8. Third valve; 9. Second pressure sensor; 10. Fourth valve; 11. Reference cylinder B; 12. Condensate cylinder; 13. Fifth valve; 14. Third pressure sensor; 15. Reference cylinder C; 16. Sixth valve; 17. Temperature sensor; 18. Sample cylinder; 19. Seventh valve; 20. Fourth pressure sensor; 21. Back pressure valve; 22. Vacuum pump; 23. Computer control system; 24. Constant temperature pool; 25. First helium cylinder; 26. Second helium cylinder; 27. Gas collection device; 28. Fifth pressure sensor. DETAILED DESCRIPTION

[0009] In order to make the purpose, technical scheme and advantages of this application clearer, the present invention is further described below in conjunction with the accompanying drawings and embodiments, and the embodiments of the present invention include but are not limited to the following embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0010] In this embodiment, the term "and / or" is merely a term used to describe the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B may represent three situations: A exists alone, A and B exist at the same time, and B exists alone.

[0011] The terms "first" and "second" in the description and claims of this embodiment are used to distinguish different objects rather than to describe a specific order of objects. For example, a first target object and a second target object are used to distinguish different target objects rather than to describe a specific order of target objects.

[0012] In the embodiments of the present application, words such as "exemplary" or "for example" are used to indicate examples, illustrations or descriptions. Any embodiment or design described as "exemplary" or "for example" in the embodiments of the present application should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of words such as "exemplary" or "for example" is intended to present related concepts in a specific way.

[0013] In the description of the embodiments of the present application, unless otherwise specified, the meaning of "multiple" refers to two or more than two. For example, multiple processing units refer to two or more processing units; multiple systems refer to two or more systems.

[0014] like Figure 1 As shown, this embodiment provides a device for testing the adsorption and desorption capacity of condensate gas. Under reservoir temperature and different pressure conditions, and taking into account the influence of condensate oil produced by phase change on the desorption behavior of condensate gas, the adsorption and desorption capacity of condensate gas is determined by an indoor experimental device and method.

[0015] In this embodiment, a method for testing the adsorption and desorption capacity of condensate gas includes the following steps: Step S1, using gas layer cuttings from a condensate gas field in the Jurassic system of the Sichuan Basin as experimental samples, and washing the cuttings samples thoroughly for salt and oil according to the core cleaning method specified in the petroleum and natural gas industry standard of the People's Republic of China "SY / T 5336-2006 Core Analysis Method", drying the samples and sieving out about 100g of cuttings with a 60-80 mesh sieve.

[0016] Step S2, keep all valves closed, and load the crushed rock sample into the sample cylinder; open the second valve, the fourth valve, the sixth valve and the seventh valve, connect the reference cylinder A, the reference cylinder B, the reference cylinder C and the sample cylinder, and evacuate the system by a vacuum pump; after the evacuation is completed, close the second valve, the sixth valve and the seventh valve, open the first valve, use the first helium bottle to introduce helium into the system, adjust the pressure of the reference cylinder A to the set pressure by the booster pump, and collect the pressure value after the air pressure in the reference cylinder A is stable; close the first valve, open the second valve, connect the reference cylinder A, the reference cylinder B and the sample cylinder, and after the pressure is balanced, collect the final pressure after the balance, and calibrate the free space volume of the first system V 1 ; Then evacuate the system and close all valves; open the fifth valve, introduce helium into the system through the second helium bottle, adjust the pressure of reference cylinder C to the set pressure through the booster pump, and collect the pressure value after the pressure in reference cylinder C stabilizes. Connect reference cylinder C and sample, and after the pressure is balanced, collect the final pressure after balance, and then calculate the free space volume of the second system V 2; Reference cylinder A, reference cylinder B, reference cylinder C and sample cylinder are placed in a constant temperature pool to simulate the rock sample reservoir temperature.

[0017] Step S3, open the first valve, close the second valve, and use a methane gas cylinder to pass methane into the reference cylinder A until the set pressure is P A Then close the first valve, open the second valve, connect the reference cylinder A and the sample cylinder, wait for the fourth pressure sensor to indicate a stable reading; open the third valve, and introduce the mixed gas into the reference cylinder B through the mixed gas cylinder to the set pressure P B ; Close the third valve, open the fourth valve, connect the reference cylinder B with the reference cylinder A and the sample cylinder, wait for the pressure of the fourth pressure sensor of the sample cylinder to stabilize for 12 hours, and record the time and pressure P x and temperature, complete the initial pressure point P x Adsorption capacity test of samples; Initial point P x The adsorption amount of condensate gas is calculated by the following formula: When the pressure is increased by the gradient, the pressure point P i The adsorption amount was calculated by the following formula: V x is the adsorption amount of condensate gas, cm 3 / g; V A , V B , V C and V The volumes of reference cylinder A, reference cylinder B, reference cylinder C and sample cylinder, cm 3 ; P A and P B are the set pressures of reference cylinder A and reference cylinder B, MPa; V 1 , V 2 is the measured free space volume of the first and second systems, cm 3 .

[0018] Step S4: close the second valve and the fourth valve, open the fifth valve, pump condensate gas into the reference cylinder C through the condensate gas bottle, and record the pressure of the reference cylinder C as P c; Close the fifth valve, open the sixth valve, connect the reference cylinder C and the sample cylinder, so that the pressure in the sample cylinder reaches the pressure point to be measured; P x Start to increase the pressure gradually from the initial point. After stabilizing at each pressure point for 12 hours, record the time, temperature and pressure. P i , the condensate gas adsorption capacity of the test sample at different pressure points.

[0019] Step S5, when the pressure point rises to the reservoir pressure, start to reduce the pressure gradually, and measure the desorption amount of condensate gas at different pressure points; keep all valves closed, then open the sixth valve, connect the reference cylinder C and the sample cylinder, control the pressure in the sample cylinder by adjusting the back pressure of the back pressure valve, and collect the gas volume at the outlet of the back pressure valve; set at least 10 pressure points during the period from the reservoir pressure gradient to the atmospheric pressure as the back pressure in turn, and record the time, pressure and pressure after each test pressure is stable for 12 hours. P 1 and temperature T ; Pressure point during desorption P 1 The desorption amount of condensate gas is calculated by the following formula: V JX is the amount of desorbed gas, cm 3 ; P max is the end point pressure of the adsorption experiment, MPa; V max is the end point pressure of the adsorption experiment P max Adsorption capacity under 3 ; P out is the pressure of the gas collection device, MPa; V out is the volume of the gas collection device, cm 3 ; N is the percentage of condensate measured in the constant mass expansion experiment, %; P 1 The pressure at each measuring point, MPa.

[0020] The experimental results show that P X =40MPa, the adsorption capacity of rock cuttings for condensate gas is 5.0935cc / g; in the process of reverse condensation, P Jx =25MPa, the constant mass expansion experiment shows that the condensate percentage is 9.48%; the desorption amount at this time is calculated by the formulaV JX =0.1053 cc / g.

[0021] The above description is not intended to impose any form of limitation on the present invention. Although the present invention has been disclosed through the above embodiments, it is not intended to limit the present invention. Any technician familiar with the profession can make some changes or modifications to equivalent embodiments of equivalent changes using the technical contents disclosed above without departing from the scope of the technical solution of the present invention. However, any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention still falls within the scope of the technical solution of the present invention.

Claims

1. A method for testing the adsorption and desorption capacity of condensate gas, which uses a condensate gas adsorption and desorption capacity testing device to perform a test experiment, characterized in that: The condensate gas adsorption and desorption test device comprises a booster pump (1), a methane gas cylinder (2) connected to the booster pump, a first helium gas cylinder (25), a mixed gas cylinder (7), a condensate gas cylinder (12), a second helium gas cylinder (26), a first valve (3) connected to the outlet section of the methane gas cylinder (2), a reference cylinder A (6) connected to the first valve, a first pressure sensor (4) arranged on the reference cylinder A (6), a second valve (5) connected to the outlet of the reference cylinder A (6), a third valve (8) connected to the outlet of the mixed gas cylinder (7), a reference cylinder B (11) connected to the third valve, a second pressure sensor (9) arranged on the reference cylinder B (11), a fourth valve (10) connected to the outlet of the reference cylinder B (11), a fifth valve (13) connected to the outlet section of the condensate gas cylinder (12), a reference cylinder C (15) connected to the fifth valve, a third pressure sensor (14) arranged on the reference cylinder C (15), a sixth valve (16) connected to the outlet of the reference cylinder C (15), and a (5), a sample cylinder (18) connected to the outlets of the fourth valve (10) and the sixth valve (16), a temperature sensor (17) arranged on the sample cylinder (18), a seventh valve (19) connected to the outlet of the sample cylinder (18), a fourth pressure sensor (20) connected to the seventh valve (19), a vacuum pump (22) connected to the outlet of the seventh valve (19), a back pressure valve (21) connected to the outlet of the sample cylinder (18), a gas collecting device (27) connected to the outlet of the back pressure valve, a fifth pressure sensor (28) arranged on the gas collecting device (27), and a computer control system respectively connected to the first pressure sensor (4), the second pressure sensor (9), the third pressure sensor (14), the fourth pressure sensor (20), the fifth pressure sensor (28) and the temperature sensor (17), wherein the sample cylinder (18) is provided with a rock cutting sample to be tested, and the reference cylinder A (6), the reference cylinder B (11), the reference cylinder C (15) and the sample cylinder (18) are arranged in a constant temperature pool (24); The method for testing the adsorption and desorption capacity of condensate gas comprises the following steps: S1. After washing the oil and salt from the downhole rock samples and drying them, the rock samples with a particle size range of 60-80 mesh are screened out by sieving method; S2. Keep all valves closed and load the rock sample into the sample cylinder (18); open the second valve (5), the fourth valve (10), the sixth valve (16) and the seventh valve (19), connect the reference cylinder A (6), the reference cylinder B (11), the reference cylinder C (15) and the sample cylinder (18), and evacuate the system with the vacuum pump (22); after the evacuation is completed, close the second valve (5), the sixth valve (16) and the seventh valve (19), open the first valve (3), use the first helium bottle (25) to introduce helium into the system, adjust the pressure of the reference cylinder A (6) to the set pressure with the booster pump (1), and collect the pressure value after the air pressure in the reference cylinder A (6) stabilizes; close the first valve (3), open the second valve (5), connect the reference cylinder A (6), the reference cylinder B (11) and the sample cylinder (18), and after the pressure is balanced, collect the final pressure after the balance, and calibrate the free space volume of the first system. V 1 ; Then, evacuate the system and close all valves; open the fifth valve (13), introduce helium into the system through the second helium bottle (26), adjust the pressure of the reference cylinder C (15) to the set pressure through the booster pump (1), and collect the pressure value after the pressure in the reference cylinder C (15) stabilizes; connect the reference cylinder C (15) and the sample cylinder (18), and after the pressure is balanced, collect the final pressure after the balance, and the free space volume of the second system can be calculated. V 2 ; Reference cylinder A (6), reference cylinder B (11), reference cylinder C (15) and sample cylinder (18) are placed in a constant temperature pool to simulate the reservoir temperature of the rock sample; S3. Open the first valve (3), close the second valve (5), and use the methane gas cylinder (2) to pass methane into the reference cylinder A (6) until the set pressure is P A Then close the first valve (3), open the second valve (5), connect the reference cylinder A (6) and the sample cylinder (18), wait for the fourth pressure sensor (20) to indicate a stable reading; open the third valve (8), and introduce the mixed gas into the reference cylinder B (11) through the mixed gas cylinder (7) until the set pressure is reached. P B ; Close the third valve (8), open the fourth valve (10), connect the reference cylinder B (11) with the reference cylinder A (6) and the sample cylinder (18), and wait for the pressure of the fourth pressure sensor (20) of the sample cylinder to stabilize for 12 hours, then record the time and pressure P x and temperature, complete the initial pressure point P x Adsorption capacity test of samples; S4. Close the second valve (5) and the fourth valve (10), open the fifth valve (13), pump condensate gas into the reference cylinder C (15) through the condensate gas bottle (12), and record the pressure of the reference cylinder C (15) as P c ; close the fifth valve (13), open the sixth valve (16), connect the reference cylinder C (15) and the sample cylinder (18), so that the pressure in the sample cylinder (18) reaches the pressure point to be measured; P x Start to increase the pressure gradually from the initial point. After stabilizing at each pressure point for 12 hours, record the time, temperature and pressure. P i , the condensate gas adsorption capacity of the test sample at different pressure points; S5. When the pressure point rises to the reservoir pressure, start to reduce the pressure gradually and measure the desorption amount of condensate gas at different pressure points; keep all valves closed, then open the sixth valve (16), connect the reference cylinder C (15) and the sample cylinder (18), control the pressure in the sample cylinder by adjusting the back pressure of the back pressure valve (21), and collect the gas volume at the outlet of the back pressure valve; set the back pressure at at least 10 pressure points during the period from the reservoir pressure gradient to the atmospheric pressure in turn, and record the time and pressure after each test pressure is stable for 12 hours. P 1 and temperature T .

2. The method for testing the adsorption and desorption capacity of condensate gas according to claim 1, characterized in that: The free space volume described in step S1 V 1 It is calculated using the ideal gas state equation.

3. The method for testing the adsorption and desorption capacity of condensate gas according to claim 1, characterized in that: In step S2 P A The setting basis is that the pressure after the reference cylinder A (6) and the sample cylinder (18) are connected is 0.5 MPa higher than the dew point pressure of the condensate gas to prevent the occurrence of reverse condensation during the gas injection process.

4. The method for testing the adsorption and desorption capacity of condensate gas according to claim 1, characterized in that: The purpose of connecting the reference cylinder A (6), the reference cylinder B (11) and the sample cylinder (18) in step S3 is to ensure that the pressure in the system is above the dew point pressure while the mixed gas satisfies the composition of the condensate gas; the mixed gas components reduce the condensate gas components, that is, after the mixed gas in the reference cylinder B (11) is injected into the system, it is mixed with the methane in the reference cylinder A (6) and the sample cylinder (18), and the gas components reduce the condensate gas components.

5. A method for testing the adsorption and desorption capacity of condensate gas according to claim 4, characterized in that: The mixed gas in the mixed gas cylinder in step S3 is the methane component under equivalent pressure plus the gas component after the mixed gas component is reduced to the condensate gas component; that is, the molar number of methane in the methane in the reference cylinder A (6) and the sample cylinder (18) is n a , the number of moles of methane in reference cylinder B (11) is n b , n a +n b is the total number of moles of methane in the equivalent condensate gas.

6. The method for testing the adsorption and desorption capacity of condensate gas according to claim 1, characterized in that: In step S3, the initial point P x The adsorption amount of condensate gas is calculated by the following formula: When the pressure is increased by the gradient, the pressure point P i The adsorption amount was calculated by the following formula: V x is the adsorption amount of condensate gas, cm 3 / g; V A , V B , V C and V The volumes of reference cylinder A (6), reference cylinder B (11), reference cylinder C (15) and sample cylinder (18), cm 3 ; P A and P B are the set pressures of reference cylinder A (6) and reference cylinder B (11), MPa; V 1 , V 2 is the measured free space volume of the first and second systems, cm 3 .

7. The method for testing the adsorption and desorption capacity of condensate gas according to claim 1, characterized in that: In the step S5, condensate oil will appear during the reverse condensation process, and the temperature of the condensate gas can be obtained by constant mass expansion experiment. T The proportion of condensate oil volume under different pressures in the total oil and gas volume under the above conditions; the volume of condensate oil is obtained by the above method, thereby eliminating the error caused by the reverse condensation phenomenon in the desorption process of condensate gas; the pressure point in the desorption stage P 1 The desorption amount of condensate gas is calculated by the following formula: V JX is the amount of desorbed gas, cm 3 ; P max is the end point pressure of the adsorption experiment, MPa; V max is the end point pressure of the adsorption experiment P max Adsorption capacity under 3 ; P out is the pressure of the gas collection device, MPa; V out is the volume of the gas collection device, cm 3 ; N is the percentage of condensate measured in the constant mass expansion experiment, %; P 1 The pressure at each measuring point, MPa.

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