Shallow natural gas sampling device and sampling method

Abstract

The present invention provides a shallow natural gas sampling device and sampling method, the shallow natural gas sampling device includes a gas collection drill pipe assembly; a gas-liquid separation container, including a first liquid discharge port, the first liquid discharge port is arranged at the bottom of the gas-liquid separation container, the gas-liquid separation container is connected to the gas collection drill pipe assembly through a gas transmission pipe; a gas booster pump, the input end of the gas booster pump is connected to the gas-liquid separation container, and the output end of the gas booster pump is connected to a gas storage device; and a sampling device is connected to the gas storage device through a gas transmission pipe. The shallow natural gas sampling device and method provided by the present invention collect shallow natural gas by a liquid discharge method, avoid mixing with impurity gases such as air during the collection process, and reduce the influence of water vapor on the detection of gas components.

Description

Technical Field

[0001] The invention relates to the technical field of natural gas collection, and in particular to a shallow layer natural gas collection and sampling device and a collection and sampling method. Background Art

[0002] Natural gas refers to all gases that exist naturally in nature, including gases formed by various natural processes in the atmosphere, hydrosphere and lithosphere. In petroleum geology, it usually refers to oilfield gas and gasfield gas, which are mainly composed of hydrocarbons and contain non-hydrocarbon gases. The main components of hydrocarbon gases are alkanes, of which methane accounts for the vast majority, and there are small amounts of ethane, propane and butane. In addition, natural gas generally contains hydrogen sulfide, carbon dioxide, nitrogen, water vapor, a small amount of carbon monoxide and trace amounts of rare gases such as helium and argon.

[0003] Shallow natural gas, which is widely distributed along the coastal and riverside areas of the Yangtze River Delta, is mainly stored in shallow marine sedimentary strata. The sediments in the strata are rich in organic matter. Under reducing conditions, anaerobic microorganisms form methane-rich gas, which accumulates continuously in the pores of the strata. It has the characteristics of wide distribution range, shallow burial depth, poor connectivity, small gas volume, large differences in gas richness and pressure. Due to the storage state and mining method of natural gas, a considerable amount of water or water vapor exists in a considerable part of the collected natural gas samples. Water will have a great interference with the test data of natural gas analysis projects. For example, too much water vapor will change the peak time of the chromatogram and interfere with the identification of low peaks such as butane and pentane; water vapor in natural gas samples will also cause a large deviation in the analysis data of monomer hydrocarbon isotopes, which will seriously cause the isotope mass spectrometer to malfunction and cannot be used normally.

[0004] The invention patent with announcement number CN204461829U specifically discloses a natural gas collection device, which includes: a gas storage device for containing natural gas; a needle valve connected to the outlet of the gas storage device; one end of the solid phase extraction device extending in the axial direction is connected to the gas outlet of the needle valve, a desiccant is provided in the solid phase extraction device, and a first sealing member for blocking the solid phase extraction device is provided at the other end of the solid phase extraction device, and the outer cover of the first sealing member is provided with a first stopper fixed to the outside of the solid phase extraction device, and a second stopper detachably connected to the first stopper is provided in the first stopper, and the second stopper can abut against the first sealing member, and the second stopper has a through hole that penetrates in the axial direction, and the through hole is used to match the outer diameter of the sampling syringe. The natural gas collection device of the present invention can accurately obtain the volume of the natural gas sample, and the syringe is reliable during the sampling process and has good sealing performance.

[0005] The above patent uses a desiccant to control the moisture or water vapor content in the natural gas sample. However, due to the unknown service life of the desiccant and the fuzzy and uncertain replacement frequency, the device has problems such as low matching degree of field natural gas exploration holes and is not suitable for collecting shallow natural gas in field boreholes.

[0006] The invention patent with announcement number CN208749350U specifically discloses a simple gas sample collection device in an exploration hole containing shallow gas formations, the collection device includes a funnel, a hose, a diaphragm pump, a gas-liquid separation container, a slurry discharge valve, a micro air pump and a vacuum gas collection bag; the funnel is connected to the diaphragm pump through a hose; the diaphragm pump is connected to the gas-liquid separation container through a hose; the top and bottom of the gas-liquid separation container are respectively provided with a micro air pump and a slurry discharge valve; the micro air pump is connected to the vacuum gas collection bag. The present invention provides a simple gas sample collection device in an exploration hole containing shallow gas formations based on geological exploration drilling, which is not limited by the buried depth of the gas-bearing layer and avoids mixing of air or impurities during the gas collection process.

[0007] Although the above patent removes particulate impurities through the above structure, air mixing is prone to occur during the vacuum air collection bag collection process, and the influence of air and other impurity gases in the collection system cannot be eliminated. The air tightness and safety during storage and transportation cannot be guaranteed. Summary of the invention

[0008] In order to solve the above problems, the shallow natural gas sampling device and method provided by the present invention collects shallow natural gas by drainage method, avoids mixing of impurity gases such as air during the collection process, and can reduce the influence of water vapor on gas component detection.

[0009] In order to achieve the above purpose, a technical solution adopted by the present invention is:

[0010] A shallow natural gas sampling and sample preparation device comprises: a gas-collecting drill pipe assembly; a gas-liquid separation container, comprising a first liquid discharge port, the first liquid discharge port is arranged at the bottom of the gas-liquid separation container, the gas-liquid separation container is connected with the gas-collecting drill pipe assembly through a gas transmission pipe; a gas booster pump, the input end of the gas booster pump is connected with the gas-liquid separation container, and the output end of the gas booster pump is connected with a gas storage device; and a sample preparation device, which is connected with the gas storage device through a gas transmission pipe; wherein the gas-liquid separation container, the gas storage device and the sample preparation device contain saturated sodium chloride solution.

[0011] Furthermore, the gas-collecting drill pipe assembly includes a first air outlet, and the first air outlet controls the on-off of gas through a first stop valve; the gas-liquid separation container also includes a first air inlet, an exhaust port and a second air outlet, and the first air inlet and the exhaust port are arranged on the side wall of the gas-liquid separation container; the second air outlet is arranged at the top of the gas-liquid separation container; the first air inlet controls the on-off of gas through the second stop valve, the exhaust port controls the on-off of gas through the third stop valve, and the second air outlet controls the on-off of gas through the fourth stop valve; the first stop valve and the second stop valve are connected through a first gas pipeline; the first drain port controls the discharge of saturated sodium chloride solution in the gas-liquid separation container through a fifth stop valve; the input end of the gas booster pump is connected to the fourth stop valve through the second gas pipeline, and the input end of the gas booster pump controls the on-off of gas through the sixth stop valve; the output end of the gas booster pump is connected to the The gas storage device is connected; the gas storage device comprises a second air inlet, a second liquid discharge port and a third air outlet; the second air inlet and the second liquid discharge port are arranged on the side wall of the gas storage device, the second liquid discharge port is arranged on the bottom wall of the gas storage device, and the third air outlet is arranged on the top wall of the gas storage device; the second air inlet controls the on-off of the gas through the seventh stop valve, and the second liquid discharge port controls the discharge of the saturated sodium chloride solution in the gas storage device through the eighth stop valve; the third air outlet controls the on-off of the gas through the ninth stop valve; and the sample preparation device comprises an air inlet needle, a liquid discharge needle, a gas collecting bottle and a rubber stopper, the sample preparation device is connected to the third air outlet through a fourth gas supply pipe, one end of the fourth gas supply pipe is connected to the ninth stop valve, and the other end of the fourth gas supply pipe is connected to the air inlet needle, the air inlet needle passes through the rubber stopper to be connected with the gas collecting bottle, and the liquid discharge needle passes through the rubber stopper to discharge the saturated sodium chloride solution in the gas collecting bottle.

[0012] Furthermore, the second outlet output end is provided with a negative pressure gauge, the negative pressure gauge input end is connected to the second outlet, and the negative pressure gauge output end is connected to the fourth stop valve; the third outlet output end is provided with a pressure gauge and a flow meter, one end of the pressure gauge is connected to the third air outlet, the other end of the pressure gauge is connected to the flow meter input end, and the flow meter output end is connected to the ninth stop valve.

[0013] Furthermore, the sample preparation device also includes a saturated sodium chloride solution and a sealing film, the saturated sodium chloride solution fills the gas collecting bottle, and the sealing film is used to seal the rubber stopper and the gas collecting bottle.

[0014] Furthermore, the gas booster pump is a micro gas booster pump.

[0015] Furthermore, the first gas pipe, the second gas pipe, the third gas pipe and the fourth gas pipe are gas hoses.

[0016] The present invention also provides a shallow natural gas sampling method, comprising the following steps: S10 exhausting the shallow natural gas sampling device, injecting a saturated sodium chloride solution into the gas-liquid separation container, the gas storage device and the sampling device, and sealing them for standby use; placing a gas pipeline in a saturated sodium chloride solution, and after the gas is filled with gas, sealing the two ends of the gas pipeline with a sealing film for standby use; S20 assembling the shallow natural gas sampling device after exhausting, and connecting the gas-liquid separation container, the gas booster pump, the gas storage device and the sampling device in sequence using the gas pipeline after exhausting; S30 checking the air tightness of the assembled shallow natural gas sampling device, discharging part of the saturated sodium chloride solution in the gas-liquid separation container and the gas storage device, and judging the air tightness by observing the change of negative pressure in the gas-liquid separation container and the gas storage device; S40 using the shallow natural gas sampling device with qualified air tightness to collect shallow natural gas; and S50 after sampling, sealing the bottle mouth with a sealing film to complete sampling.

[0017] Further, the S10 step specifically includes: S11 exhausting the gas-liquid separation container, closing the second stop valve, the third stop valve and the fifth stop valve of the gas-liquid separation container, opening the fourth stop valve, injecting a saturated sodium chloride solution from the first air inlet, and the fourth stop valve is put into use after it is filled; S12 exhausting the gas storage device, closing the seventh stop valve and the eighth stop valve of the gas storage device, opening the ninth stop valve, injecting a saturated sodium chloride solution through the third air outlet, and closing the ninth stop valve after it is filled, and put it into use; S13 exhausting the sample preparation device, filling at least one of the gas collecting bottles with a saturated sodium chloride solution, covering the rubber stopper, and inverting it for use; S14 exhausting the gas pipe, placing the first gas pipe, the second gas pipe, the third gas pipe and the fourth gas pipe in a saturated sodium chloride solution, and after they are filled with exhaust, sealing both ends with a sealing film for use. The step S20 also includes installing the negative pressure gauge between the second air outlet and the fourth stop valve, and installing the pressure gauge and the flow meter in sequence between the third air outlet and the ninth stop valve; the step S30 specifically includes: S31 air tightness inspection of the gas-liquid separation container, closing the first stop valve, the second stop valve, the third stop valve and the fourth stop valve, opening the fifth stop valve, the saturated sodium chloride solution is discharged from the first drain port under the action of gravity, the fifth stop valve is closed after a certain amount is discharged, and the pressure value of the negative pressure gauge is observed to determine the air tightness; S32 air tightness inspection of the gas storage device, closing the seventh stop valve and the ninth stop valve, opening the eighth stop valve, the saturated sodium chloride solution is discharged from the first drain port under the action of gravity, and ... and sodium chloride solution are discharged from the second liquid discharge port under the action of gravity, and the pressure value of the pressure gauge is observed to determine the air tightness; the S40 step specifically includes the following steps: open the first stop valve, and when the value of the negative pressure gauge on the top of the gas-liquid separation container is displayed as 0, open the fourth stop valve, the sixth stop valve, and the seventh stop valve to start gas storage, and when the pressure gauge displays 1±0.5Mpa, close the seventh stop valve, open the ninth stop valve, insert the air inlet needle into the rubber stopper, and insert the liquid discharge needle at the same time to prepare the sample; in the S50 step, when the saturated sodium chloride solution in the gas collecting bottle remains about 1 / 3, pull out the air inlet needle and the liquid discharge needle, seal the bottle mouth with a sealing film, invert it, and complete the sampling process.

[0018] Furthermore, the gas booster pump is a micro gas booster pump.

[0019] Furthermore, the first gas pipe, the second gas pipe, the third gas pipe and the fourth gas pipe are gas hoses.

[0020] The above technical solution of the present invention has the following advantages compared with the prior art:

[0021] (1) The shallow layer natural gas is collected by negative pressure generated by the drainage method, and impurity gases such as air are avoided during the collection process. The operation is simple, the samples are easy to store, and the operation process and sample storage and transportation are explosion-proof and highly safe. The influence of moisture on the detection of natural gas components is reduced.

[0022] (2) The saturated sodium chloride method is used to collect and preserve shallow natural gas. On the one hand, the solubility of natural gas in water is reduced. On the other hand, the saturated vapor pressure of saturated sodium chloride solution is lower than that of pure water, which can greatly reduce water evaporation and reduce the impact of water vapor on the detection of natural gas components. The gas collection method has the advantages of good airtightness and safety and explosion-proof. The saturated sodium chloride method has high reliability and superiority in collecting and preserving natural gas.

[0023] (3) The device of the present invention has a simple structure and principle, the materials are easy to obtain, and the assembly and disassembly are convenient. The gas collection operation method using the sampling and sample preparation device of the present invention is simple and easy to promote. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The technical solutions and beneficial effects of the present invention will be made apparent by describing in detail the specific embodiments of the present invention in conjunction with the accompanying drawings.

[0025] Figure 1 The figure is a schematic structural diagram of a shallow natural gas sampling device according to an embodiment of the present invention;

[0026] Figure 2 The figure is a flow chart of a shallow natural gas sampling method according to an embodiment of the present invention;

[0027] Figure 3 The figure is a flow chart of step S10 according to an embodiment of the present invention;

[0028] Figure 4 FIG. 4 is a flow chart of step S30 according to an embodiment of the present invention.

[0029] Reference numerals:

[0030] 1 gas collection drill pipe assembly, 11 first gas outlet, 12 first stop valve, 2 gas-liquid separation container, 21 first liquid discharge port, 22 first gas inlet, 23 exhaust port, 24 second gas outlet, 25 second stop valve, 26 third stop valve, 27 fourth stop valve, 28 fifth stop valve, 29 first gas pipeline, 3 gas booster pump, 31 second gas pipeline, 32 sixth stop valve, 33 third gas pipeline, 4 gas storage device, 41 second gas inlet, 42 second liquid discharge port, 43 third gas outlet, 44 seventh stop valve, 45 eighth stop valve, 46 ninth stop valve, 5 sample preparation device, 51 gas inlet needle, 52 liquid discharge needle, 53 gas collection bottle, 54 rubber stopper, 55 fourth gas pipeline, 6 negative pressure gauge, 7 pressure gauge, 8 flow meter. DETAILED DESCRIPTION

[0031] 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 those skilled in the art without creative work are within the scope of protection of the present invention.

[0032] The embodiment of the present invention discloses a shallow layer natural gas sampling device, such as Figure 1 As shown, the shallow natural gas sampling device comprises: a gas collection drill pipe assembly 1, a gas-liquid separation container 2, a gas booster pump 3, a gas storage device 4 and a sampling device 5. The gas-liquid separation container 2, the gas storage device 4 and the sampling device 5 contain saturated sodium chloride solution.

[0033] The gas-gathering drill pipe assembly 1 comprises a first gas outlet 11 , and the first gas outlet 11 controls the on-off of gas through a first stop valve 12 .

[0034] The gas-liquid separation container 2 includes a first liquid discharge port 21, a first air inlet 22, an exhaust port 23 and a second air outlet 24. The first liquid discharge port 21 is arranged at the bottom of the gas-liquid separation container 2. The first air inlet 22 and the exhaust port 23 are arranged on the side wall of the gas-liquid separation container 2. The second air outlet 24 is arranged at the top of the gas-liquid separation container 2. The gas-liquid separation container 2 is connected to the gas-collecting drill pipe assembly 1 through a gas pipeline. The first air inlet 22 controls the on-off of the gas through the second stop valve 24, the exhaust port 23 controls the on-off of the gas through the third stop valve 26, and the second air outlet 24 controls the on-off of the gas through the fourth stop valve 27. The first stop valve 12 and the second stop valve 25 are connected through a first gas pipeline 29. The first liquid discharge port 21 controls the discharge of the saturated sodium chloride solution in the gas-liquid separation container 2 through the fifth stop valve 28. The output end of the second outlet 24 is provided with a negative pressure gauge 6, the input end of the negative pressure gauge 6 is connected to the second outlet 24, and the output end of the negative pressure gauge 6 is connected to the fourth stop valve 27. The first gas pipe 29 can be a metal pipe, a plastic pipe, etc., and a gas hose is preferably used in the embodiment of the present invention. The gas-liquid separation container 2 contains a saturated sodium chloride solution.

[0035] The input end of the gas booster pump 3 is connected to the gas-liquid separation container 2, and the output end of the gas booster pump 3 is connected to the gas storage device 4. The input end of the gas booster pump 3 is connected to the fourth stop valve 27 through the second gas pipeline 31, and the input end of the gas booster pump 3 controls the on-off of the gas through the sixth stop valve 32. The output end of the gas booster pump 3 is connected to the gas storage device 4 through the third gas pipeline 33. The gas booster pump is preferably a micro gas booster pump. The second gas pipeline 31 and the third gas pipeline 33 can be metal pipes, plastic pipes, etc., and the embodiment of the present invention preferably uses a gas hose.

[0036] The gas storage device 4 includes a second gas inlet 41, a second liquid discharge port 42 and a third gas outlet 43. The second gas inlet 41 and the second liquid discharge port 42 are arranged on the side wall of the gas storage device 4, the second liquid discharge port 42 is arranged on the bottom wall of the gas storage device 4, and the third gas outlet 43 is arranged on the top wall of the gas storage device 4; the second gas inlet 41 controls the on-off of the gas through the seventh stop valve 44, and the second liquid discharge port 42 controls the discharge of the saturated sodium chloride solution in the gas storage device 4 through the eighth stop valve 45. The third gas outlet 43 controls the on-off of the gas through the ninth stop valve 46. The output end of the third outlet 43 is provided with a pressure gauge 7 and a flow meter 8. One end of the pressure gauge 7 is connected to the third gas outlet 43, the other end of the pressure gauge 7 is connected to the input end of the flow meter 8, and the output end of the flow meter 8 is connected to the ninth stop valve 46. The gas storage device 4 contains a saturated sodium chloride solution.

[0037] The sample preparation device 5 is connected to the gas storage device 4 through an air supply pipe. The sample preparation device 5 includes an air inlet needle 51, a liquid discharge needle 52, a gas collecting bottle 53, a rubber stopper 54 and a sealing film. The sample preparation device 5 is connected to the third gas outlet 43 through a fourth air supply pipe 55. One end of the fourth air supply pipe 55 is connected to the ninth stop valve 46, and the other end of the fourth air supply pipe 55 is connected to the air inlet needle 51. The air inlet needle 51 passes through the rubber stopper 54 to communicate with the gas collecting bottle 53. The liquid discharge needle 52 passes through the rubber stopper 54 to discharge the saturated sodium chloride solution in the gas collecting bottle 53. The fourth air supply pipe 55 can be a metal pipe, a plastic pipe, etc., and the embodiment of the present invention preferably uses a gas supply hose.

[0038] like Figure 2As shown, the embodiment of the present invention also discloses a shallow natural gas sampling method, comprising the following steps: S10 exhausts the shallow natural gas sampling device, injects a saturated sodium chloride solution into the gas-liquid separation container 2, the gas storage device 4 and the sampling device 5, and seals them for use; places the gas pipeline in the saturated sodium chloride solution, and after the gas is filled with gas, the two ends of the gas pipeline are sealed with a sealing film for use. S20 assembles the shallow natural gas sampling device after exhaust, and uses the gas pipeline after exhaust to sequentially connect the gas-liquid separation container 2, the gas booster pump 3, the gas storage device 4 and the sampling device 5. S30 checks the air tightness of the assembled shallow natural gas sampling device, discharges part of the saturated sodium chloride solution in the gas-liquid separation container 2 and the gas storage device 4, and judges the air tightness by observing the changes in the negative pressure of the gas-liquid separation container 2 and the gas storage device 4. S40 uses the shallow natural gas sampling and preparation device with qualified air tightness to collect shallow natural gas; and S50 after sampling, the bottle mouth is sealed with a sealing film to complete the sample preparation. The gas booster pump is preferably a micro gas booster pump.

[0039] like Figure 3 As shown, the step S10 specifically includes: S11 exhausts the gas-liquid separation container 2, closes the second stop valve 25, the third stop valve 26 and the fifth stop valve 28 of the gas-liquid separation container 2, opens the fourth stop valve 27, injects saturated sodium chloride solution from the first air inlet 22, and the fourth stop valve 27 is ready for use after being filled. S12 exhausts the gas storage device 4, closes the seventh stop valve 44 and the eighth stop valve 45 of the gas storage device 4, opens the ninth stop valve 46, injects saturated sodium chloride solution through the third air outlet 43, and closes the ninth stop valve 46 after being filled, and is ready for use. S13 exhausts the sample preparation device 4, fills at least one gas collection bottle 53 with saturated sodium chloride solution, covers the rubber stopper 54, and inverts it for use. S14 exhausts the gas pipeline, places the first gas pipeline 29, the second gas pipeline 31, the third gas pipeline 33 and the fourth gas pipeline 55 in a saturated sodium chloride solution, and after being fully exhausted, seals both ends with a sealing film for use. The first gas pipe 29 , the second gas pipe 31 , the third gas pipe 33 and the fourth gas pipe 55 may be metal pipes, plastic pipes, etc., and gas hoses are preferred in the embodiment of the present invention.

[0040] The step S20 further includes installing the negative pressure gauge 6 between the second gas outlet 24 and the fourth stop valve 27, and sequentially installing the pressure gauge 7 and the flow meter 8 between the third gas outlet 43 and the ninth stop valve 46. After the assembly is completed, the gas collection drill pipe 1 is placed in the gas-bearing layer, and after gas is detected to be ejected, the first stop valve 12 is closed.

[0041] like Figure 4As shown, the step S30 specifically includes: S31 air tightness inspection of the gas-liquid separation container 2, closing the first stop valve 12, the second stop valve 25, the third stop valve 26 and the fourth stop valve 27, opening the fifth stop valve 28, the saturated sodium chloride solution is discharged from the first drain port 21 under the action of gravity, and the fifth stop valve 28 is closed after a certain amount (preferably 2 / 3 of the total volume of the saturated sodium chloride solution) is discharged, and the pressure value of the negative pressure gauge 6 is observed and recorded. When the reading of the negative pressure gauge 6 does not change, negative pressure is formed in the gas-liquid separation container, and the air tightness of the gas-liquid separation container meets the requirements. S32 air tightness inspection of the gas storage device 4, closing the seventh stop valve 44 and the ninth stop valve 46, opening the eighth stop valve 45, the saturated sodium chloride solution is discharged from the second drain port 42 under the action of gravity, and the pressure value of the pressure gauge 7 is observed. When the pressure value does not change, the air tightness of the gas storage device 4 meets the requirements.

[0042] The S40 step specifically includes the following steps: open the first stop valve 12 to start collecting shallow natural gas; when the value of the negative pressure gauge 6 on the top of the gas-liquid separation container 2 is displayed as 0, open the fourth stop valve 27, the sixth stop valve 32, and the seventh stop valve 44 to start storing gas; when the pressure gauge 7 displays 1±0.5Mpa, close the seventh stop valve 44, open the ninth stop valve 46, insert the air inlet needle 51 into the rubber stopper 54, and insert the liquid discharge needle 52 at the same time to prepare samples.

[0043] In step S50, when about 1 / 3 of the saturated sodium chloride solution remains in the gas collecting bottle 53, the gas inlet needle 51 and the liquid discharge needle 52 are pulled out, the bottle mouth is sealed with a sealing film, and the bottle is inverted to complete the sampling process. On the one hand, the saturated sodium chloride solution reduces the solubility of natural gas in water. On the other hand, the saturated vapor pressure of the saturated sodium chloride solution is lower than that of pure water, which can greatly reduce the evaporation of water. Using saturated sodium chloride solution to store shallow natural gas has good airtightness, safety and reliability.

[0044] The natural gas detection data obtained by the shallow natural gas sampling method of the embodiment of the present invention are shown in Table 1 below.

[0045] Table 1. Content of shallow natural gas components

[0046]

[0047] It can be seen from Table 1 that the oxygen content is 0, indicating that no air is mixed in during the entire process of collecting gas, and the storage and transportation of the samples are explosion-proof and highly safe.

[0048] The above description is only an exemplary embodiment of the present invention, and does not limit the scope of patent protection of the present invention. Any equivalent structure or equivalent process transformation made by using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the scope of patent protection of the present invention.

Claims

1. A method for collecting and preparing samples of shallow natural gas, characterized in that: A shallow layer natural gas sampling and sample preparation device is used, and the shallow layer natural gas sampling and sample preparation device comprises: Gas collection drill pipe assembly (1); The gas-liquid separation container (2) comprises a first liquid discharge port (21), wherein the first liquid discharge port (21) is arranged at the bottom of the gas-liquid separation container (2), and the gas-liquid separation container (2) is connected to the gas collection drill pipe assembly (1) via a gas transmission pipe; a gas booster pump (3), wherein the input end of the gas booster pump (3) is connected to the gas-liquid separation container (2), and the output end of the gas booster pump (3) is connected to the gas storage device (4); and A sample preparation device (5) is connected to the gas storage device (4) via a gas transmission pipe; The gas-liquid separation container (2), the gas storage device (4) and the sample preparation device (5) contain a saturated sodium chloride solution; The gas collection drill pipe assembly (1) comprises a first gas outlet (11), and the first gas outlet (11) controls the on and off of gas through a first stop valve (12); The gas-liquid separation container (2) further comprises a first gas inlet (22), an exhaust port (23) and a second gas outlet (24); the first gas inlet (22) and the exhaust port (23) are arranged on the side wall of the gas-liquid separation container (2); the second gas outlet (24) is arranged on the top of the gas-liquid separation container (2); the first gas inlet (22) controls the on-off of gas through a second stop valve (25); the exhaust port (23) controls the on-off of gas through a third stop valve (26); the second gas outlet (24) controls the on-off of gas through a fourth stop valve (27); the first stop valve (12) and the second stop valve (25) are connected through a first gas transmission pipe (29); the first liquid discharge port (21) controls the discharge of saturated sodium chloride solution in the gas-liquid separation container (2) through a fifth stop valve (28); The input end of the gas booster pump (3) is connected to the fourth stop valve (27) via the second gas delivery pipe (31), and the input end of the gas booster pump (3) controls the on and off of the gas via the sixth stop valve (32); the output end of the gas booster pump (3) is connected to the gas storage device (4) via the third gas delivery pipe (33); The gas storage device (4) comprises a second gas inlet (41), a second liquid discharge port (42) and a third gas outlet (43); the second gas inlet (41) and the second liquid discharge port (42) are arranged on the side wall of the gas storage device (4), the second liquid discharge port (42) is arranged on the bottom wall of the gas storage device (4), and the third gas outlet (43) is arranged on the top wall of the gas storage device (4); the second gas inlet (41) controls the on-off of gas through a seventh stop valve (44), and the second liquid discharge port (42) controls the discharge of saturated sodium chloride solution in the gas storage device (4) through an eighth stop valve (45); the third gas outlet (43) controls the on-off of gas through a ninth stop valve (46); and The sample preparation device (5) comprises an air intake needle (51), a liquid discharge needle (52), a gas collecting bottle (53) and a rubber stopper (54); the sample preparation device (5) is connected to the third gas outlet (43) via a fourth gas supply pipe (55); one end of the fourth gas supply pipe (55) is connected to a ninth stop valve (46); the other end of the fourth gas supply pipe (55) is connected to the air intake needle (51); the air intake needle (51) passes through the rubber stopper (54) to communicate with the gas collecting bottle (53); the liquid discharge needle (52) passes through the rubber stopper (54) to discharge the saturated sodium chloride solution in the gas collecting bottle (53); The shallow natural gas sampling method includes the following steps: S10: the shallow natural gas sampling and sample preparation device is subjected to exhaust treatment: a saturated sodium chloride solution is injected into the gas-liquid separation container (2), the gas storage device (4) and the sample preparation device (5), and the gas is sealed for standby use; a gas pipeline is placed in the saturated sodium chloride solution, and after the gas pipeline is filled with the saturated sodium chloride solution and exhausted, both ends of the gas pipeline are sealed with a sealing film for standby use; S20 assembling the shallow natural gas sampling device after exhaust: using the exhausted gas transmission pipe to sequentially connect the gas-liquid separation container (2), the gas booster pump (3), the gas storage device (4) and the sampling device (5); S30: Checking the air tightness of the assembled shallow natural gas sampling device: discharging part of the saturated sodium chloride solution in the gas-liquid separation container (2) and the gas storage device (4), and judging the air tightness by observing the change of negative pressure in the gas-liquid separation container (2) and the gas storage device (4); S40: collecting shallow natural gas using the shallow natural gas sampling and preparation device with qualified air tightness; collecting shallow natural gas by generating negative pressure through the liquid drainage method; and After S50 sampling is completed, the bottle mouth is sealed with sealing film to complete the sample preparation.

2. The shallow layer natural gas sampling method according to claim 1, characterized in that: A negative pressure gauge (6) is provided at the output end of the second air outlet (24), the input end of the negative pressure gauge (6) is connected to the second air outlet (24), and the output end of the negative pressure gauge (6) is connected to the fourth stop valve (27); a pressure gauge (7) and a flow meter (8) are provided at the output end of the third air outlet (43), one end of the pressure gauge (7) is connected to the third air outlet (43), the other end of the pressure gauge (7) is connected to the input end of the flow meter (8), and the output end of the flow meter (8) is connected to the ninth stop valve (46).

3. The shallow layer natural gas sampling method according to claim 2 is characterized in that: The step S10 specifically comprises: S11 exhausting the gas-liquid separation container (2), closing the second stop valve (25), the third stop valve (26) and the fifth stop valve (28) of the gas-liquid separation container (2), opening the fourth stop valve (27), injecting saturated sodium chloride solution from the first air inlet (22), closing the fourth stop valve (27) after the solution is filled, and waiting for use; S12 exhausting the gas storage device (4), closing the seventh stop valve (44) and the eighth stop valve (45) of the gas storage device (4), and opening the ninth stop valve (46), inject saturated sodium chloride solution through the third gas outlet (43), close the ninth stop valve (46) after filling, and wait for use; S13 exhaust the sample preparation device (5), fill at least one of the gas collecting bottles (53) with saturated sodium chloride solution, cover the rubber stopper (54), and turn it upside down for use; S14 exhaust the gas pipes, place the first gas pipe (29), the second gas pipe (31), the third gas pipe (33) and the fourth gas pipe (55) in the saturated sodium chloride solution, and after they are full of exhaust gas, seal the two ends with sealing film and wait for use; The step S20 further includes installing the negative pressure gauge (6) between the second air outlet (24) and the fourth stop valve (27), and installing the pressure gauge (7) and the flow meter (8) in sequence between the third air outlet (43) and the ninth stop valve (46); The step S30 specifically includes: S31: checking the air tightness of the gas-liquid separation container (2), closing the first stop valve (12), the second stop valve (25), the third stop valve (26) and the fourth stop valve (27), opening the fifth stop valve (28), and discharging the saturated sodium chloride solution from the first liquid discharge port (21) under the action of gravity. After a certain amount of the solution is discharged, the fifth stop valve (28) is closed, and the pressure value of the negative pressure gauge (6) is observed to determine the air tightness; S32: checking the air tightness of the gas storage device (4), closing the seventh stop valve (44) and the ninth stop valve (46), opening the eighth stop valve (45), and discharging the saturated sodium chloride solution from the second liquid discharge port (42) under the action of gravity. The pressure value of the pressure gauge (7) is observed to determine the air tightness; The step S40 specifically comprises the following steps: opening the first stop valve (12), and when the value of the negative pressure gauge (6) at the top of the gas-liquid separation container (2) is displayed as 0, opening the fourth stop valve (27), the sixth stop valve (32), and the seventh stop valve (44) to start gas storage, and when the pressure gauge (7) displays 1±0.5Mpa, closing the seventh stop valve (44), opening the ninth stop valve (46), inserting the air inlet needle (51) into the rubber stopper (54), and inserting the liquid discharge needle at the same time to prepare the sample; In the step S50, when about 1 / 3 of the saturated sodium chloride solution remains in the gas collection bottle (53), the gas inlet needle (51) and the liquid discharge needle (52) are pulled out, the bottle mouth is sealed with a sealing film, and the bottle is inverted to complete the sampling process.

4. The shallow layer natural gas sampling method according to claim 1, characterized in that: The gas booster pump (3) is a micro gas booster pump.

5. The shallow layer natural gas sampling method according to claim 1, characterized in that: The first gas delivery pipe (29), the second gas delivery pipe (31), the third gas delivery pipe (33) and the fourth gas delivery pipe (55) are gas delivery hoses.

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