Gas-liquid separation device and gas detection method thereof

Abstract

The invention discloses a gas-liquid separation device and a gas detection method thereof. The device comprises a separation cylinder and a gas collection tank, the separation cylinder is communicated with a liquid storage tank through an input pipeline, and an electric ball valve is arranged on the input pipeline; a piston is further arranged in the separation cylinder, a driving device is connected to the piston, a containing cavity is formed between the piston and the inner wall of the separation cylinder, the gas collecting tank is communicated with the containing cavity through a connecting pipeline A, and a gas-liquid separation electromagnetic valve, a flow limiting valve and a one-way check valve are arranged on the connecting pipeline A; the device has the advantages that the oil-gas separation effect can be enhanced, the accuracy of carbon dioxide output metering is improved, and meanwhile the oil and gas field carbon dioxide sealing efficiency can be evaluated conveniently.

Description

Technical Field

[0001] The invention relates to the technical field of fluid degassing, and in particular to a gas-liquid separation device and a gas detection method thereof. Background Art

[0002] In the field of oilfield exploitation, injecting gas into the bottom of the oilfield is a common and effective method to improve the efficiency of crude oil recovery. The injected gas can not only squeeze the crude oil out from the bottom of the oilfield through physical action, but also has multiple functions such as reducing crude oil viscosity, reducing oil-water interfacial tension, promoting crude oil volume expansion, improving the flow ratio of crude oil and water, achieving light component extraction and extraction, exerting molecular diffusion, utilizing dissolved gas drive, achieving miscible effect and improving formation permeability.

[0003] The coordinated operation of carbon dioxide flooding and storage has become a key path to achieve green and low-carbon development. This method can organically combine energy development with environmental protection, which is of great significance to promoting the sustainable development of the global economy and society. However, carbon dioxide has good solubility in crude oil, which means that the expelled crude oil often contains a large amount of carbon dioxide. The existing conventional oil and gas separation process has obvious defects and cannot efficiently, comprehensively and conveniently separate the gas and liquid of the produced fluid. This will lead to inaccurate detection of the carbon dioxide content, which will affect the subsequent evaluation of the efficiency of carbon dioxide storage.

[0004] Therefore, it is urgent to develop a new type of gas-liquid separation device and its gas detection method. Summary of the invention

[0005] The object of the present invention is to provide a gas-liquid separation device and a gas detection method thereof to solve the problems raised in the above background technology.

[0006] To achieve the above-mentioned object, in a first aspect, the present invention provides the following technical solutions: a gas-liquid separation device, comprising a separation cylinder and a gas collection tank; The separation cylinder is connected to the liquid storage tank through an input pipe, and an electric ball valve is arranged on the input pipe; a piston is also arranged in the separation cylinder, and a driving device is connected to the piston, and a receiving chamber is formed between the piston and the inner wall of the separation cylinder; The gas collection tank is connected to the accommodating chamber through a connecting pipe A, and the connecting pipe A is provided with a gas-liquid separation solenoid valve, a flow limiting valve and a one-way check valve.

[0007] Preferably, the separation cylinder and the gas collection tank are both provided with pressure and temperature sensors, which can detect the pressure and temperature conditions in the separation cylinder and the gas collection tank.

[0008] Preferably, the gas-liquid separation solenoid valve is arranged on one end of the connecting pipe A close to the separation cylinder, the one-way check valve is arranged on one end of the connecting pipe A close to the gas collection tank, and the flow limiting valve is arranged between the gas-liquid separation solenoid valve and the one-way check valve.

[0009] Preferably, it also includes a control unit, which is connected to the electric ball valve, the driving device, the gas-liquid separation solenoid valve, the flow limiting valve, and the two pressure and temperature sensors.

[0010] In a second aspect, the present invention provides the following technical solution: a gas detection method, comprising the following steps: Sampling operation: open the electric ball valve, and the driving device drives the piston to move in the separation cylinder. Usually, in order to facilitate the pushing of the piston and the subsequent discharge of gas, the piston is usually set at the bottom of the separation cylinder, and the connection part between the separation cylinder and the connecting pipe is set at the top of the separation cylinder. Therefore, the piston moves toward the bottom of the separation cylinder in the separation cylinder, increasing the volume of the containing chamber, thereby reducing the pressure in the containing chamber; A containing area is formed between the piston and the inner wall of the separation cylinder. The fluid is stored in the containing area. The piston moves in the separation cylinder to increase the volume of the containing area. Under the condition that other conditions remain unchanged, increasing the volume of the containing area in the separation cylinder will cause the pressure in the separation cylinder to decrease. By reducing the pressure in the containing cavity, the fluid flows from the liquid storage tank into the containing cavity under the action of pressure. It should be noted that in the operation of each step, if some valves do not mention their switch state, they are defaulted to be closed; Decompression and gas evolution: Close the electric ball valve, and the driving device drives the piston to move in the separation cylinder, increasing the volume of the accommodating chamber, thereby reducing the pressure in the accommodating chamber. According to Henry's law, the pressure reduction will lead to a decrease in the solubility of the gas in water. Some of the detection gas originally dissolved in the water will be dissolved out of the water, thus completing the precipitation of the detection gas; Exhaust operation: Open the gas-liquid separation solenoid valve, and the driving device drives the piston to move in the separation cylinder, pushing the fluid and the precipitated detection gas to move toward the connection part between the separation cylinder and the connecting pipe. The precipitated gas will flow into the connecting pipe A, and pass through the gas-liquid separation solenoid valve, the flow limiting valve and the one-way check valve, and finally flow into the gas collection tank; Gas analysis: Since the separation cylinder and the pipeline may contain other gases, the gas in the gas collection tank is a mixed gas containing the detection gas. The gas collection tank is connected to the gas analyzer through the connecting pipeline B. The gas analyzer can analyze the volume concentration of the detection gas in the mixed gas; Calculation operation: According to the volume concentration of the detection gas, the mass of the detection gas in the mixed gas is obtained, and according to the saturated solubility of the detection gas in oil and water, the mass of the detection gas in the liquid phase of the fluid is calculated, and then the mass of the detection gas in the fluid is obtained. The total mass of the detection gas in the fluid in the storage tank is calculated by the mass proportion of the detection gas in this part of the fluid, and the mass of the detection gas remaining underground is obtained by recording the total amount of detection gas injected. The efficiency of gas sealing is calculated by comparing the mass of the detection gas remaining underground with the total amount injected; Gas collection judgment: Since the gas analyzer has certain requirements for the total amount of analyzed gas, a total of V1 liter of mixed gas is required for analysis. Since the volume V2 of the gas collection tank is limited, at the same temperature, the more gas is injected into the gas collection tank, the greater the pressure value P1 in the gas collection tank. When P1 in the gas collection tank reaches the set value, it means that the gas collected in the gas collection tank has reached the required V1 liter, and the gas pressure in the gas analyzer is P2. When the pressure value in the collection tank reaches P1, the gas collection is completed. The calculation formula of the pressure value P1 in the gas tank is: , where P2 represents the pressure value in the gas analyzer; V1 represents the volume of gas to be collected under the pressure of P2; V2 represents the volume of the gas tank; P1 represents the actual pressure value in the gas tank after V1 liters of gas is injected into the gas tank from the outside; Repeat gas analysis operation: When the pressure in the gas collection tank is less than P1, it means that gas still needs to be collected. At this time, the pressure reduction and gas analysis operation and exhaust operation are repeated until the pressure value in the gas collection tank reaches P1; Fluid pressure judgment: During the exhaust operation, the mixed gas flows from the separation tank into the gas collection tank through the connecting pipe A. At this time, it is only necessary to move the piston in the separation cylinder to squeeze the space in the separation tank so that the gas moves into the gas collection tank through the connecting pipe A. Therefore, the pressure value in the separation tank needs to be greater than or equal to the pressure value P1 in the gas collection tank to avoid the difficulty of the gas moving into the gas collection tank under the push of the piston. Therefore, it is necessary to set a pressure threshold p3 for the pressure in the separation tank. When P3 is not less than p1, pressure reduction, gas analysis and exhaust operations can be performed; when P3 is less than P1, pressure reduction, gas analysis and exhaust operations cannot be performed at this time, and the fluid in the separation tank needs to be discharged through the output pipe set on the separation tank, and the sampling operation is performed.

[0011] Preferably, a gas processing device is provided on the connecting pipe B. During the process of transporting the mixed gas in the gas tank to the gas analyzer, in order to reduce the influence of impurities in the mixed gas on the detection of the gas analyzer, the mixed gas is pre-processed by the gas processing device, including gas filtration, gas drying and other procedures.

[0012] Preferably, a pressure reducing valve is provided between the connecting pipe B and the gas processing device, which can adjust the gas pressure output by the gas collection tank.

[0013] Compared with the prior art, the invention has the following beneficial effects: by setting a driving device to drive the piston to move in the separation cylinder, the crude oil can be extracted and the detection gas in the crude oil can be separated out by reducing the pressure. In addition, the detection gas in the crude oil can be repeatedly extracted according to the pressure value set in the gas collection tank, so as to obtain the mass of the detection gas contained in the crude oil. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic diagram of the overall structure of the present invention.

[0015] In the figure: 1. separation cylinder; 2. input pipeline; 3. liquid storage tank; 4. electric ball valve; 5. piston; 6. driving device; 7. accommodating chamber; 8. connecting pipeline A; 9. gas-liquid separation solenoid valve; 10. flow limiting valve; 11. one-way check valve; 12. gas collection tank; 13. connecting pipeline B; 14. pressure reducing valve; 15. collection solenoid valve; 16. gas processing device; 17. gas analyzer. DETAILED DESCRIPTION

[0016] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0017] See also Figure 1 As shown, the present invention provides a gas-liquid separation device and a gas detection method thereof. Currently, in the field of crude oil extraction, the gas-liquid separation device and the gas detection method thereof have a wide range of application prospects.

[0018] Especially in the northwest region of my country, the climate is relatively dry, the relative humidity is usually between 20% and 50%, the temperature is usually between -10 degrees Celsius and +40 degrees Celsius, and the pressure in the oil field is usually between 1 MPa and tens of MPa. In such an environment, oil field exploitation usually uses gas injection to drive oil, and the driven crude oil contains water and gas. The oil, gas and water three-phase mixed fluid (referred to as fluid, the same below) is injected into the liquid storage tank 3 for subsequent processing.

[0019] The present invention aims to solve the problem of inaccurate gas separation in the prior art. The effect of driving out crude oil is achieved by injecting gas underground. However, during the gas injection process, the efficiency of gas sealing underground will directly affect the recovery rate and mining cost of crude oil. Therefore, after underground gas injection, the evaluation of gas sealing efficiency is a very important procedure.

[0020] In the gas flooding method, the injected gas is mainly carbon dioxide, nitrogen or natural gas. In the following text, carbon dioxide will be used as an example for ease of reading, but it does not mean that only carbon dioxide as a gas for flooding can realize this solution. In this case, it means that the crude oil is driven out by carbon dioxide in the early stage, and some carbon dioxide is also dissolved in the driven crude oil, which will be stored in the liquid storage tank 3.

[0021] The present application discloses a gas-liquid separation device, comprising a separation cylinder 1 and a gas collection tank 12; The separation cylinder 1 is connected to the liquid storage tank 3 through the input pipe 2, and the liquid storage tank 3 is mainly used to store the extracted crude oil. The input pipe 2 is provided with an electric ball valve 4, which can control the flow of the input pipe 2, which belongs to the prior art and will not be described here; the separation cylinder 1 is also provided with a piston 5, and the piston 5 is connected to a driving device 6, which is used to drive the piston 5 to move in the separation cylinder 1. The driving device can be a motor driving device or a pneumatic driving device, etc., which is intended to drive the piston 5 to make reciprocating vertical movements. In reality, there are many such driving devices 6, which belong to the prior art and will not be described here.

[0022] Both the separation cylinder 1 and the gas collection tank 12 are provided with pressure relief valves, through which the pressure in the separation cylinder 1 and the gas collection tank 12 can be reduced.

[0023] A receiving chamber 7 is formed between the piston 5 and the inner wall of the separation cylinder 1 , and the receiving chamber 7 is used to receive crude oil. The input pipeline 2 is connected to the receiving chamber 7 .

[0024] In actual operation, the separation cylinder 1 is usually placed vertically on the ground, the driving device is arranged below the separation cylinder 1, and the piston 5 is also arranged at the lower part of the separation cylinder 1. Therefore, the accommodating chamber 7 is formed by the top, side and piston 5 of the separation cylinder 1, and the input pipeline 2 is generally arranged at the top of the separation cylinder 1 to facilitate the injection of crude oil.

[0025] The piston 5 is tightly connected to the inner wall of the separation cylinder 1, which has been maturely applied in the prior art and will not be described in detail here.

[0026] The gas collection tank 12 is connected to the accommodating chamber 7 through the connecting pipe A8, which is in the same position as the input pipe 2 and is generally arranged at the top of the separation cylinder 1 to facilitate the subsequent gas extraction. The connecting pipe A8 is provided with a gas-liquid separation solenoid valve 9, a flow limiting valve 10 and a one-way check valve 11.

[0027] The gas-liquid separation solenoid valve 9 is used to separate gas and fluid to prevent fluid impurities from being contained in the gas, and can protect downstream equipment and pipelines and prevent fluid from entering the gas collection tank 12 and subsequent equipment. The gas-liquid separation solenoid valve 9 is usually installed at the front end of the connecting pipeline A8 (close to the gas outlet) to remove fluid impurities before the gas enters other equipment; The flow limiting valve 10 is used to limit the gas flow, control the gas flow rate and pressure in the subsequent pipeline, prevent the gas flow rate from being too fast or the pressure from being too high, ensure the stable operation of the system, and can adjust the gas flow to avoid damage to the pipeline or equipment due to excessive flow rate or pressure. At the same time, it can also prevent the pressure in the separation cylinder 1 from dropping rapidly and causing flash evaporation. The flow limiting valve 10 is usually installed downstream of the gas-liquid separation solenoid valve 9 so that the flow control can be performed after the gas is separated; The one-way check valve 11 is used to prevent the gas from flowing in the opposite direction, ensuring that the gas can only flow from the gas outlet to the collection part. When the gas pressure drops or stops flowing, it will automatically close to prevent the gas from flowing back, protect the pipeline and equipment, and ensure the one-way flow of the gas. The one-way check valve 11 is usually installed at the end of the connecting pipeline A8 (the end close to the gas collection tank 12) as the last protection device.

[0028] Therefore, the gas-liquid separation solenoid valve 9, the flow limiting valve 10 and the one-way check valve 11 are arranged on the connecting pipe A8 from left to right between the separation cylinder 1 and the gas collection tank 12. This order can maximize the protection of the pipeline system and ensure the purity of the gas, stable flow and unidirectional flow.

[0029] The gas-liquid separation device also includes a control unit, which is connected to the electric ball valve 4, the drive device 6, the gas-liquid separation solenoid valve 9, the flow limiting valve 10, and two pressure and temperature sensors. The control unit can remotely control the electric ball valve 4, the drive device 6, the gas-liquid separation solenoid valve 9, the flow limiting valve 10, and the pressure and temperature sensors, and receive the operating parameters of the above components, thereby realizing remote control.

[0030] When performing gas detection, it is first necessary to take out a portion of crude oil sample from the liquid storage tank 3 .

[0031] In the sampling operation, the electric ball valve 4 is opened, and the driving device 6 drives the piston 5 to move downward in the separation cylinder 1, so that the volume of the accommodating chamber 7 increases. In a short period of time, when other conditions remain unchanged, the increase in the volume of the accommodating chamber 7 will cause the pressure in the accommodating chamber 7 to decrease. By reducing the pressure in the accommodating chamber 7, the crude oil flows from the liquid storage tank 3 into the accommodating chamber 7 under the action of pressure.

[0032] It should be noted that in the operation of each step, if the switch status of some valves is not mentioned, they are assumed to be closed.

[0033] Gas evolution by decompression: After a certain amount of crude oil is injected into the separation cylinder 1 (usually a flow meter is provided on the input pipeline to monitor the amount of crude oil flowing in), the electric ball valve 4 is closed, and the driving device 6 drives the piston 5 to move downward in the separation cylinder 1 (the displacement distance of the piston 5 mainly depends on the air pressure in the separation cylinder 1, which needs to be determined according to the actual situation), increasing the volume of the accommodating chamber 7, thereby reducing the pressure in the accommodating chamber 7. According to Henry's law, the decrease in pressure will lead to a decrease in the solubility of gas in the fluid, so that part of the gas (including carbon dioxide) originally dissolved in the crude oil is dissolved from the fluid, thereby completing the precipitation of carbon dioxide.

[0034] Exhaust operation: The precipitated carbon dioxide will float above the separation cylinder 1 mixed with other gases. Turn off the drive device 6 and open the gas-liquid separation solenoid valve 9. The drive device 6 drives the piston 5 to move upward in the separation cylinder 1, pushing the crude oil and the mixed gas (the mixed gas is a mixture of the detection gas and other gases in the equipment, the same below) to move toward the top of the separation cylinder 1. The mixed gas will flow into the connecting pipe A8, pass through the gas-liquid separation solenoid valve 9, the limiting valve 10 and the one-way check valve 11, and finally flow into the gas collection tank 12. After the exhaust is completed, the gas-liquid separation solenoid valve 9 is closed.

[0035] Gas analysis and calculation operation: The gas collection tank 12 is connected to a gas analyzer 17 through a connecting pipe B13, and a solenoid valve is also provided on the connecting pipe B13 to control the opening and closing of the connecting pipe B13. The gas analyzer 17 can analyze the volume concentration of carbon dioxide in the mixed gas, calculate the volume of carbon dioxide according to the total volume of the mixed gas, and obtain the mass of carbon dioxide according to the density of carbon dioxide.

[0036] At the same time, based on the saturated solubility of carbon dioxide in oil and water, the mass of carbon dioxide in all the extracted crude oil is calculated.

[0037] The above calculation methods, including calculating the volume of carbon dioxide in the mixed gas, calculating the mass of carbon dioxide in the mixed gas in combination with the density of carbon dioxide, and calculating the mass of carbon dioxide in all the crude oil extracted into the separation cylinder 1 by the saturated solubility of carbon dioxide in oil and water, all belong to the prior art. For details, please refer to Chinese Patent 2024116196985, a carbon dioxide output metering system and method in a well site, which will not be described in detail here.

[0038] For example, 3 liters of carbon dioxide are precipitated from 10 liters of crude oil, from which it can be inferred that the volume ratio of carbon dioxide in crude oil is 3 / 10, and the total volume of carbon dioxide contained in the expelled crude oil can be obtained based on the total amount of crude oil expelled by injected carbon dioxide. By comparing the total amount of carbon dioxide injected during oil recovery with the total volume of carbon dioxide contained in the expelled crude oil, the storage rate of carbon dioxide in the formation can be obtained.

[0039] The mass of carbon dioxide can also be calculated from its density, and the storage rate of carbon dioxide in the formation can be calculated by comparing the masses.

[0040] When using nitrogen, natural gas or other gases to drive out crude oil, the principle of calculating the storage rate is the same as the above-mentioned calculation method of carbon dioxide, which will not be elaborated here.

[0041] It is worth noting that both the separation cylinder 1 and the gas collection tank 12 are provided with pressure and temperature sensors, which can detect the pressure and temperature in the separation cylinder 1 and the gas collection tank 12 respectively.

[0042] Among them, when the above-mentioned gas analyzer 17 detects the mixed gas, there are requirements for the volume of the mixed gas. For example, when the gas analyzer 17 analyzes the analysis gas, the pressure in the gas analyzer 17 is P2, and the gas analyzer 17 requires a minimum volume of V1 liters of mixed gas for detection. Since the volume V2 of the gas tank 12 is fixed, the more mixed gas is injected into the gas tank 12, the greater the pressure P1 in the gas tank 12. When the pressure value in the gas tank 12 reaches P1, it means that the mixed gas in the gas tank 12 at this time meets the minimum detection requirements of the gas analyzer 17. The calculation formula of P1 is: ;When the pressure in the gas tank 12 is less than P1, it means that the gas content in the gas tank 12 does not meet the standard at this time, and it is necessary to continue to repeat the pressure reduction and gas analysis operation and the exhaust operation until the pressure value in the gas tank 12 reaches P1.

[0043] During the exhaust operation, the mixed gas flows from the separation cylinder 1 into the gas collection tank 12 through the connecting pipe A8. At this time, the piston 5 only needs to move in the separation cylinder 1 to squeeze the space in the separation cylinder 1, so that the gas moves into the gas collection tank 12 through the connecting pipe A8. Therefore, the pressure value in the separation cylinder 1 needs to be greater than or equal to the pressure value P1 in the gas collection tank 12 to prevent the gas from having difficulty flowing into the gas collection tank 12 under the push of the piston 5.

[0044] Therefore, it is necessary to set a pressure value P3 for the pressure in the separation cylinder 1. When P3 is not less than P1, the pressure reduction, gas analysis and exhaust operation can be performed; when P3 is less than P1, the pressure reduction, gas analysis and exhaust operation cannot be performed at this time, and the fluid in the separation cylinder 1 needs to be discharged through the output pipeline set on the separation cylinder 1. Close the gas-liquid separation solenoid valve 9, and repeat the sampling operation until P3 is greater than P1, and then continue to perform the pressure reduction, gas analysis and exhaust operation until the pressure value in the gas sampling tank 12 reaches P1.

[0045] At the same time, the connecting pipe B13 is provided with a gas processing device 16. In the process of transporting the mixed gas in the gas tank 12 to the gas analyzer 17, in order to reduce the influence of impurities in the mixed gas on the detection of the gas analyzer 17, the mixed gas is pre-processed by the gas processing device 16, including gas filtering, gas drying and other procedures, which are determined according to the actual situation. There are corresponding solutions in the prior art, which will not be described in detail here.

[0046] In actual operation, since the mixed gas in the gas tank 12 needs to be transported to the gas analyzer 17 through the connecting pipe B13, the pressure value in the gas analyzer 17 is the standard atmospheric pressure, which is expressed as 0.1MPa. For example, the volume of the gas tank 12 is 1 liter, and the mixed gas required for this collection is 10 liters. 10 liters means that 10 liters of mixed gas need to be detected under standard atmospheric pressure. Therefore, ignoring the influence of other factors (such as temperature), the pressure in the gas tank 12 is calculated by the formula to be 1MPa. Therefore, the pressure value P3 of the separation cylinder 1 needs to be greater than or equal to 1MPa.

[0047] In order to avoid excessive pressure in the gas tank 12 and damage to subsequent equipment and pipelines, a pressure reducing valve 14 is installed on the end of the connecting pipe B13 close to the gas tank 12. The pressure reducing valve 14 can adjust the output mixed gas pressure value according to demand. In order to facilitate the gas passing through the pressure reducing valve 14 to flow to the gas analyzer 17 under the action of pressure, the pressure parameter set by the pressure reducing valve 14 should be greater than P2. Under normal circumstances, in subsequent devices, the pressure tolerance range is within 1MPa, so the pressure parameter set by the pressure reducing valve 14 should generally be less than 1MPa.

[0048] Among them, a collection solenoid valve 15 is also provided on the connecting pipeline B13 between the pressure reducing valve 14 and the gas processing device 16 for controlling the on-off of the connecting pipeline B13.

[0049] During the sampling operation, the piston 5 moves to reduce the air pressure in the accommodating chamber 7, thereby sucking the crude oil into the separation cylinder 1. In order to better control the extraction volume, the first extraction volume V3 is set before the operation starts. The bottom area of ​​the accommodating chamber 7 in the separation cylinder 1 is S1, from which the movement stroke H1 of the piston 5 in the separation cylinder 1 can be obtained: ;In the pressure reduction and gas analysis operation, the piston 5 moves downward to the maximum stroke (i.e. H1) and then stops to perform a gas-liquid separation. At this time, the separation cylinder 1 needs to be left still. After standing for a period of time, observe the pressure and temperature sensor installed on the separation cylinder 1. When the pressure and temperature in the separation cylinder 1 are stable, it means that the gas and fluid in the separation cylinder 1 have reached a dissolved equilibrium state, and record the current temperature and pressure values.

[0050] During the exhaust operation, the piston 5 pushes the mixed gas to flow into the gas collection tank 12. In order to ensure the stability of the exhaust process and the pressure in the separation cylinder 1 is not greater than the equilibrium pressure during the exhaust process, and to avoid the problem of the re-dissolution of the analyzed gas, the flow rate of the gas discharged from the separation cylinder 1 should not be greater than the flow rate V4 of the flow limiting valve 10, and the flow rate of the gas discharged from the separation cylinder 1 depends on the speed V5 of the piston 5 moving in the separation cylinder 1. Therefore, the relationship between V5 and V4 is: It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-restrictive, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all changes within the meaning and range of equivalents of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

Claims

1. A gas-liquid separation device, characterized in that: It comprises a separation cylinder (1) and a gas collection tank (12); The separation cylinder (1) is connected to the liquid storage tank (3) via an input pipe (2), and an electric ball valve (4) is provided on the input pipe (2); a piston (5) is also provided in the separation cylinder (1), and a driving device (6) is connected to the piston (5); a receiving chamber (7) is formed between the piston (5) and the inner wall of the separation cylinder (1); The gas collection tank (12) is connected to the accommodating chamber (7) via a connecting pipe A (8), and the connecting pipe A (8) is provided with a gas-liquid separation electromagnetic valve (9), a flow limiting valve (10) and a one-way check valve (11).

2. The gas-liquid separation device according to claim 1, characterized in that: The separation cylinder (1) and the gas collection tank (12) are both provided with pressure and temperature sensors.

3. The gas-liquid separation device according to claim 2, characterized in that: The gas-liquid separation solenoid valve (9) is arranged on one end of the connecting pipe A (8) close to the separation cylinder (1), the one-way check valve (11) is arranged on one end of the connecting pipe A (8) close to the gas collection tank (12), and the flow limiting valve (10) is arranged between the gas-liquid separation solenoid valve (9) and the one-way check valve (11).

4. The gas-liquid separation device according to claim 3, characterized in that: It comprises a control unit, wherein the control unit is connected to the electric ball valve (4), the drive device (6), the gas-liquid separation electromagnetic valve (9), the flow limiting valve (10), and the two pressure and temperature sensors.

5. A gas detection method applied to the gas-liquid separation device according to any one of claims 2 to 4, characterized in that: The following steps are involved: Sampling operation: the electric ball valve (4) is opened, and the driving device (6) drives the piston (5) to move in the separation cylinder (1), thereby increasing the volume of the accommodating chamber (7), thereby reducing the pressure in the accommodating chamber (7), and driving the fluid from the liquid storage tank (3) to flow into the accommodating chamber (7); Decompression and gas evolution: the electric ball valve (4) is closed, and the driving device (6) drives the piston (5) to move in the separation cylinder (1), thereby reducing the pressure in the accommodating chamber (7) and causing part of the detection gas in the fluid to dissolve out of the water; Exhaust operation: open the gas-liquid separation solenoid valve (9), drive the piston (5) to move in the separation cylinder (1), push the precipitated detection gas to flow to the connecting pipe A (8), and pass through the gas-liquid separation solenoid valve (9), the flow limiting valve (10) and the one-way check valve (11), and flow into the gas collection tank (12); Gas analysis: the gas sampling tank (12) is connected to a gas analyzer (17) via a connecting pipe B (13), and the gas analyzer (17) is used to analyze the volume concentration of the relevant gas; Calculation operation: According to the volume concentration of the detection gas, the mass of the detection gas in the fluid is obtained by calculation; Gas collection judgment: the gas analyzer (17) needs to collect V1 liter of mixed gas, the volume of the gas collection tank (12) is V2 liters, the pressure when V1 liter of mixed gas is collected in the gas collection tank (12) is P1, and the gas pressure in the gas analyzer (17) is P2. When the pressure value in the gas collection tank reaches P1, the gas collection is completed; Repeat the gas analysis operation: when the pressure in the gas collection tank (12) is less than P1, it means that gas still needs to be collected. At this time, the pressure reduction gas analysis operation and the exhaust operation are repeated until the pressure value in the gas collection tank (12) reaches P1; Fluid pressure judgment: During the exhaust operation, the mixed gas flows from the separation cylinder (1) into the gas collection tank (12) through the connecting pipe A (8). The pressure value in the separation cylinder (1) needs to be greater than or equal to the pressure value P1 in the gas collection tank (12). A pressure threshold value P3 is set for the pressure in the separation cylinder (1). When P3 is not less than P1, the pressure reduction, gas analysis and exhaust operation can be performed; When P3 is less than P1, the pressure reduction, gas analysis and exhaust operations cannot be performed, and the fluid in the separation cylinder (1) needs to be discharged through the output pipe provided on the separation cylinder (1), and the sampling operation and subsequent operations need to be performed.

6. The gas detection method according to claim 5, characterized in that: The connecting pipeline B (13) is provided with a gas processing device (16).

7. The gas detection method according to claim 6, characterized in that: A pressure reducing valve (14) is provided between the connecting pipe B (13) and the gas processing device (16).

8. The gas detection method according to claim 7, characterized in that: In the calculation operation steps, the mass of the detection gas in the fluid is calculated as follows: based on the volume concentration of the detection gas, the mass of the detection gas in the fluid can be obtained by the ideal gas equation, the mass of the detection gas in the liquid phase of the fluid is calculated based on the saturated solubility of the detection gas in oil and water, and the total mass of the detection gas in the fluid in the liquid storage tank (3) is calculated by the mass ratio of the detection gas in this part of the fluid.

9. The gas detection method according to claim 8, characterized in that: In the gas collection judgment step, the calculation formula of P1 is: ; Wherein, V1 is the volume of the mixed gas that the gas analyzer (17) needs to collect, V2 is the volume of the gas collection tank (12), P1 is the pressure value when V1 liters of mixed gas are collected in the gas collection tank (12), and P2 is the gas pressure in the gas analyzer (17).

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