Oil well carbon dioxide sampling device and use method

Abstract

The invention relates to the technical field of oil well gas sampling, in particular to an oil well carbon dioxide sampling device and a using method.The oil well carbon dioxide sampling device comprises a primary separator and a separation sampler, and the separation sampler comprises a base, a barrel, a top cover and a partition plate assembly. The device is reasonable and compact in structure and convenient to use, the depressurization separation space of an oil-gas sample is effectively increased through the primary separator and the separation sampler, so that the oil-gas sample can be subjected to two-stage depressurization separation, oil-gas separation in the oil-gas sample is more thorough, oil-gas splashing is effectively avoided, a detection instrument is prevented from being polluted and damaged, and the detection efficiency is improved. The environmental pollution caused by oil gas leakage is avoided; an oil gas sample is always in a sealed state in a depressurization separation process, so that air interference can be effectively avoided, the accuracy of carbon dioxide concentration detection is ensured, and gas sample extraction is more in line with a sampling standard; the constant-pressure deflation valve arranged at the top of the separation sampler can prevent pressure build-up in the separation sampler, so that potential safety hazards are avoided.

Description

Technical Field

[0001] The invention relates to the technical field of oil well gas sampling, and relates to an oil well carbon dioxide sampling device and a use method. Background Art

[0002] Carbon dioxide injection and huff-and-puff oil recovery technology refers to a new technology that injects a certain amount of carbon dioxide into the reservoir crude oil, shuts down the well for a period of time, and changes the physical properties of the crude oil such as viscosity and density after the crude oil is fully in contact with carbon dioxide, while improving the flow characteristics of the fluid, thereby improving the crude oil recovery rate. Experiments at home and abroad have shown that the mechanism of carbon dioxide injection and oil increase is mainly to expand the volume of crude oil, reduce the viscosity of crude oil, and extract it. It has a significant effect on reducing the water content of oil reservoirs in the late stage of ultra-high water content. It is one of the effective methods to increase the ultimate recovery rate of oil reservoirs, especially suitable for single-well enhanced recovery. The United States has long used carbon dioxide injection and enhanced recovery to increase crude oil production, accounting for 31% of the total production of national enhanced recovery projects. Although the domestic carbon dioxide injection and enhanced recovery technology started late, many carbon dioxide injection and huff-and-puff pilot tests have been successful.

[0003] During the test injection of carbon dioxide in the oil field, on-site personnel need to obtain all data and fill in all information every day according to the plan. At present, when collecting information, the method adopted is to take gas samples and test the carbon dioxide concentration during the oil well venting process. The gas sampling and testing of carbon dioxide concentration are performed at the outlet of the existing sampler. In actual use, it has the following shortcomings: the existing sampler has a small space, and the oil and gas cannot be completely separated. When measuring gas at the outlet, oil and gas splashes are prone to occur, which pollutes and damages the detector; the sealing is poor and is seriously disturbed by air, which will lead to inaccurate measurement of carbon dioxide concentration; when sampling, the oil and gas in the sampling bag do not meet the standards; there is only one outlet, which is easy to cause improper pressure operation when taking gas samples, and there are operational risks. Summary of the invention

[0004] The present invention provides an oil well carbon dioxide sampling device and a method for using the same, which overcomes the deficiencies of the above-mentioned prior art and can effectively solve the problems of the existing samplers and sampling methods, such as small sampler space, incomplete oil and gas separation, easy oil and gas splashing and air interference during sampling, and non-standard sampling.

[0005] One of the technical solutions of the present invention is achieved through the following measures: an oil well carbon dioxide sampling device, including a primary separator and a separation sampler, the separation sampler including a base, a cylinder, a top cover and a partition assembly, the top cover and the base are detachably installed on the inner side of the upper end and the inner side of the lower end of the cylinder respectively, slots are provided on the inner side of the front and rear of the cylinder corresponding to the upper side of the base, a partition assembly is inserted in the slot corresponding to the position below the top cover, the partition assembly divides the inner side of the cylinder into a separation chamber and an exhaust chamber on the left and right sides, an air inlet is provided on the cylinder corresponding to the upper left side of the separation chamber, an air inlet pipe is fixedly installed in the air inlet, a primary separator capable of performing preliminary pressure reduction and separation on oil and gas samples is detachably installed on the other end of the air inlet pipe, a sampling port and an exhaust port are provided on the cylinder corresponding to the upper position of the exhaust chamber at intervals front and back, a sampling valve is fixedly installed in the sampling port, and a gas measuring valve is fixedly installed in the exhaust port.

[0006] The following are further optimizations and / or improvements to the above technical solutions: The above-mentioned partition assembly may include a filter partition and a handle. The filter partition is inserted into the slot corresponding to the position below the top cover. The filter partition includes a blind plate portion, a filter portion and a bending portion. The filter partition corresponding to the air inlet position is the blind plate portion. The filter plate corresponding to the position above the sampling port and the exhaust port is bent toward one side of the exhaust cavity to form a bending portion that can block the exhaust cavity. A handle is fixedly installed on the upper side of the bending portion. The filter partition corresponding to the blind plate portion and the outer side of the bending portion is the filtering portion. The filtering portion is provided with a plurality of filter holes that pass through from left to right.

[0007] The above-mentioned primary separator may include a separation bottle, a bottle cap, an air inlet connector and an air outlet connector. The bottle cap is sealed and installed on the upper end of the separation bottle. The bottle cap is provided with air inlet holes and air outlet holes that can connect the inside and outside of the separation bottle at intervals. An air inlet connector is provided on the side of the air inlet hole connected to the outside world, and an air outlet connector is provided on the side of the air outlet hole connected to the outside world. The other end of the air outlet connector is detachably installed together with the air inlet pipe.

[0008] The above-mentioned separation sampler may also include a constant-pressure air release valve. A pressure relief hole penetrating from top to bottom is provided in the middle of the top cover, and a constant-pressure air release valve is provided in the pressure relief hole.

[0009] An oil collecting groove with an opening facing upward may be provided on the upper side of the base, and the lower part of the partition assembly is located in the oil collecting groove.

[0010] The above-mentioned separation sampler may also include a handle and a sealing ring. The handle is fixedly installed on the outer front part of the cylinder, and sealing rings are provided between the inner side of the upper end of the cylinder and the outer side of the lower part of the cover, and between the inner side of the lower end of the cylinder and the outer side of the upper part of the base.

[0011] The outer side of the lower part of the base and the outer side of the upper part of the top cover may be evenly distributed along the circumference with at least two wrench holes opening outwards.

[0012] The second technical solution of the present invention is achieved through the following measures: a method for using an oil well carbon dioxide sampling device, which is carried out according to the following method: in the first step, the primary separator is connected to the gas outlet of the existing wellhead sampler through a soft air pipe and an air nozzle, and then the primary separator is connected to the separation sampler through an air inlet pipe, and then the gas measuring valve is connected to the gas detector, and the sampling valve is connected to the sampling bag; in the second step, the sampling valve on the sampler is opened, and the oil and gas samples enter the separation bottle of the primary separator from the oil drain port of the sampler for pressure reduction and preliminary separation; in the third step, the oil and gas samples after preliminary separation reach the separation chamber of the separation sampler through the air inlet pipe, and the oil and gas samples hit the blind plate when spraying out for secondary separation, and the separated oil flows into the bottom of the cylinder, and the separated gas sample enters the exhaust chamber through the filter hole, and finally the gas samples reach the gas detector for detection and the sampling bag for collection and sampling.

[0013] The present invention has a reasonable and compact structure and is easy to use. The primary separator and the separation sampler connected together by the air inlet pipe can form a two-stage separation device, which effectively increases the pressure reduction and separation space of the oil and gas sample, so that the oil and gas sample can achieve two-stage pressure reduction and separation, making the oil and gas separation in the oil and gas sample more thorough. The gas sample of the oil and gas components separated by pressure reduction can effectively prevent oil and gas splashing, effectively avoid pollution and damage to the detection instrument and environmental pollution caused by oil and gas leakage; the oil and gas sample is always in a sealed state during the flow and pressure reduction and separation process, which can effectively avoid external air interference, thereby ensuring the accuracy of carbon dioxide concentration detection in the gas sample, and making the gas sample extraction more composite sampling standard; the constant pressure vent valve arranged on the top of the separation sampler can keep the pressure in the primary separator and the separation sampler constant, prevent pressure holding, and effectively avoid safety hazards; in addition, all components in the primary separator and the separation sampler are split-type design, which is easier to disassemble and assemble, greatly reducing the difficulty of cleaning and maintenance of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Attached Figure 1 It is a schematic diagram of the three-dimensional cross-sectional structure of the separation sampler in Examples 1-7 of the present invention.

[0015] Attached Figure 2 For attachment Figure 1 Schematic diagram of the three-dimensional structure of the connection between the middle base and the cylinder.

[0016] Attached Figure 3 For attachment Figure 1 Schematic diagram of the three-dimensional structure of the middle top cover.

[0017] Attached Figure 4 For attachment Figure 1 Schematic diagram of the three-dimensional structure of the middle partition assembly.

[0018] Attached Figure 5 It is a schematic diagram of the three-dimensional structure of Examples 1-7 of the present invention.

[0019] The codes in the accompanying drawings are: 1 is the base, 2 is the cylinder, 3 is the top cover, 4 is the slot, 5 is the separation chamber, 6 is the exhaust chamber, 7 is the air inlet, 8 is the air inlet pipe, 9 is the exhaust port, 10 is the sampling valve, 11 is the air measuring valve, 12 is the handle, 13 is the blind plate part, 14 is the filter part, 15 is the bending part, 16 is the filter hole, 17 is the separation bottle, 18 is the bottle cap, 19 is the air inlet connector, 20 is the air outlet connector, 21 is the constant pressure air release valve, 22 is the oil collecting tank, 23 is the handle, 24 is the sealing ring, 25 is the wrench hole, and 26 is the pressure relief hole. DETAILED DESCRIPTION

[0020] The present invention is not limited by the following embodiments, and specific implementation methods can be determined based on the technical solution of the present invention and actual conditions.

[0021] In the present invention, for the convenience of description, the relative position relationship of each component is described according to the attached Figure 1 The positional relationships such as front, back, top, bottom, left, and right are described according to the layout directions of the drawings in the specification.

[0022] The present invention will be further described below in conjunction with embodiments and drawings: Embodiment 1: As attached Figure 1-5 As shown, the oil well carbon dioxide sampling device includes a primary separator and a separation sampler, and the separation sampler includes a base 1, a cylinder 2, a top cover 3 and a partition assembly. The top cover 3 and the base 1 are detachably installed on the inner side of the upper end and the inner side of the lower end of the cylinder 2, respectively. The front inner side and the rear inner side of the cylinder 2 corresponding to the upper side of the base 1 are provided with slots 4, and the slots 4 corresponding to the lower side of the top cover 3 are plugged into the partition assembly. The partition assembly divides the inner side of the cylinder 2 into a separation chamber 5 and an exhaust chamber 6 on the left and right sides. An air inlet 7 is provided on the cylinder 2 corresponding to the upper left side of the separation chamber 5, and an air inlet pipe 8 is fixedly installed in the air inlet 7. The other end of the air inlet pipe 8 is detachably installed with a primary separator capable of performing preliminary pressure reduction and separation on oil and gas samples. A sampling port and an exhaust port 9 are spaced apart from each other on the cylinder 2 corresponding to the upper part of the exhaust chamber 6, and a sampling valve 10 is fixedly installed in the sampling port, and a gas measuring valve 11 is fixedly installed in the exhaust port 9.

[0023] During use, the primary separator and the separation sampler connected together by the air inlet pipe 8 can effectively increase the separation space of the oil and gas sample. Through the two-stage pressure reduction separation, the oil and gas in the oil and gas sample can be separated more thoroughly, effectively avoiding oil and gas splashing and reducing air interference, so that the gas sample in the sampling container is more in line with the standard to ensure the accuracy of the carbon dioxide concentration measurement; in addition, when the high-pressure oil and gas sample flows into the separation chamber 5, it will hit the partition assembly, causing it to rebound to the inner wall of the cylinder 2, accelerating the oil and gas separation, so that the oil and gas separation effect of the oil and gas sample is better The separated oil and gas gather into droplets and accumulate at the bottom of the cylinder 2. After the separated natural gas such as carbon dioxide rises over the upper end of the partition assembly and enters the exhaust chamber 6, the pressure will further drop. After it flows out from the sampling port and the exhaust port 9, it can effectively prevent the oil and gas from splashing onto the detection instrument, avoiding contamination and damage to the detection instrument; after the sampling container is connected to the sampling valve 10, the gas detection instrument can also be connected to the gas measuring valve 11, so that sampling and gas detection can be carried out at the same time, which effectively improves the sampling operation efficiency and greatly saves the sampling operation time.

[0024] According to the needs, the primary separator can be realized by a separation cup or a separation bottle 17 or a separation tank, etc. The upper end of the primary separator is respectively provided with an outlet pipe for easy connection with the air inlet pipe 8, and an air inlet pipe for easy entry of oil and gas samples. When sampling is required, the air inlet pipe of the primary separator can be connected to the air outlet of the existing sampler; to prevent leakage of oil and gas samples, sealing members can be provided between the cylinder 2 and the top cover 3 and the base 1, and the detachable installation between the cylinder 2 and the top cover 3 and the base 1 can be achieved by screw connection, card connection, plug-in connection or threaded fastener connection in the prior art; the sampling valve 10 and the gas measuring valve 11 can be achieved by ball valves, butterfly valves or gate valves in the prior art.

[0025] The above oil well carbon dioxide sampling device can be further optimized and / or improved according to actual needs: Embodiment 2: As attached Figure 1 , 4 As shown, the partition assembly includes a filter partition and a handle 12. The filter partition is inserted into the slot 4 corresponding to the position below the top cover 3. The filter partition includes a blind plate portion 13, a filter portion 14 and a bending portion 15. The filter partition corresponding to the position of the air inlet 7 is the blind plate portion 13. The filter plate corresponding to the position above the sampling port and the exhaust port 9 is bent toward one side of the exhaust cavity 6 to form a bending portion 15 that can block the exhaust cavity 6. The handle 12 is fixedly installed on the upper side of the bending portion 15. The filter partition corresponding to the outer side of the blind plate portion 13 and the bending portion 15 is the filter portion 14. The filter portion 14 is provided with a plurality of filter holes 16 that pass through from left to right.

[0026] By such arrangement, when the high-pressure oil and gas sample enters the separation chamber 5 from the air inlet 7, it will directly hit the blind plate 13, and the oil and gas sample can be separated again in the process of rebounding, and the separated oil and gas gather into droplets and sink to the bottom of the cylinder; because the bent filter partition, the base 1 and the cylinder 2 can block the upper end of the exhaust chamber 6 to form a relatively closed exhaust chamber, the separated carbon dioxide and other natural gas gases can only enter the exhaust chamber 6 through the filter hole 16 on the filter part 14, and in the process of the gas passing through the filter hole 16 to enter the exhaust chamber 6, it will be throttled by the filter hole 16 The dual functions of pressure reduction and adsorption filtration further separate the oil and gas contained in the gas and adsorb and filter it through the filter hole 16, thereby obtaining a purer gas sample, greatly reducing the oil and gas components in the gas sample, making the gas sampling more in line with the gas sampling standard, effectively improving the accuracy of carbon dioxide concentration detection, and avoiding oil and gas splashing to contaminate the sampling instrument; the oil produced by deposition and filtration will be uniformly collected at the bottom of the cylinder, which is more convenient for subsequent unified treatment, thereby avoiding pollution of the wellhead environment; when the sampling is completed, when the filter baffle needs to be cleaned, the handle 12 is more convenient to quickly remove the filter baffle from the cylinder 2. According to the needs, the filtering effect of the filter part 14 can also be achieved by the filter screen or filter cotton or the semi-permeable membrane or plate filter element that only allows gas to pass through in the prior art.

[0027] Embodiment 3: As attached Figure 5 As shown, the primary separator includes a separation bottle 17, a bottle cap 18, an air inlet connector 19 and an air outlet connector 20. The bottle cap 18 is sealed on the upper end of the separation bottle 17, and the bottle cap 18 is provided with air inlet holes and air outlet holes that can connect the inside and outside of the separation bottle 17. An air inlet connector 19 is provided on the side of the air inlet connected to the outside, and an air outlet connector 20 is provided on the side of the air outlet connected to the outside. The other end of the air outlet connector 20 is detachably mounted on the air inlet pipe 8.

[0028] With such an arrangement, since the volume of the separation bottle 17 is much larger than that of the pipeline, the high-pressure oil and gas sample enters the separation bottle 17 through the air inlet connector 19, which will reduce the pressure of the oil and gas sample, thereby causing the oil and gas components contained in the oil and gas sample to undergo initial separation and sedimentation, and the separated gas will float up and enter the air inlet pipe 8 through the air outlet connector 20; in addition, when the high-pressure oil and gas sample hits the bottle wall and bottom of the separation bottle 17, it will accelerate the oil and gas separation, thereby achieving a better oil and gas separation effect in the oil and gas sample.

[0029] According to requirements, a sealing pad or a sealing ring may be provided between the separation bottle 17 and the bottle cap 18. The separation bottle 17 can be realized by various empty beverage bottles or mineral water bottles that are compatible with the bottle cap 18 in the prior art, so as to save costs. The separation bottle 17 and the bottle cap 18 can be quickly disassembled and assembled by screw connection in the prior art, so that the oil in the separation bottle 17 can be collected and centrally processed, thereby avoiding environmental pollution; to facilitate the installation of the bottle cap 18 and the separation bottle 17, a wrench groove or a wrench table that is convenient for clamping a wrench may be provided on the outside of the bottle cap 18, which is a hexagonal external wrench table in this embodiment; the air inlet connector 19 may be provided with threads so that it can be connected to the air outlet of the existing sampler through a matching quick connector and a pipeline, and the air outlet connector 20 and the air inlet pipe 8 can be detachably installed by screw connection or cable tie or clamp or quick connector in the prior art.

[0030] Embodiment 4: As attached Figure 1 , 3 As shown in , 5 , the separation sampler also includes a constant pressure air release valve 21 , and a pressure relief hole 26 penetrating from top to bottom is provided in the middle of the top cover 3 , and a constant pressure air release valve 21 is provided in the pressure relief hole 26 .

[0031] By such arrangement, when the pressure in the cylinder 2 exceeds the set pressure, it can discharge part of the gas through the constant pressure release valve 21 to release the pressure, so as to prevent the occurrence of pressure abuse during the oil and gas sample collection process and avoid potential safety hazards. According to the requirements, the constant pressure release valve 21 can be realized by an automatic exhaust valve, a pressure cooker safety valve or an automatic pressure relief valve in the prior art.

[0032] Embodiment 5: As attached Figure 1 As shown, an oil collecting groove 22 with an opening facing upward is provided on the upper side of the base 1 , and the lower part of the partition assembly is located in the oil collecting groove 22 .

[0033] Through such an arrangement, the separated oil can be better collected, so that all the oil is collected in the oil collecting tank 22, which greatly reduces the oil leakage from the gap between the cylinder 2 and the base 1, and is more convenient for centralized treatment of waste oil and cleaning and maintenance of the separation sampler; in addition, since the lower part of the partition assembly is located in the oil collecting tank 22, the lower part of the partition assembly may not have a filtering function.

[0034] Embodiment 6: As attached Figure 1 , 2 As shown in , 5 , the separation sampler also includes a handle 23 and a sealing ring 24 . The handle 23 is fixedly installed on the front outer side of the cylinder 2 , and sealing rings 24 are provided between the inner side of the upper end of the cylinder 2 and the outer side of the lower part of the cover body, and between the inner side of the lower end of the cylinder 2 and the outer side of the upper part of the base 1 .

[0035] This arrangement makes it easier to carry and move the separation sampler; the sealing ring 24 can effectively prevent the oil and gas sample from leaking from the gap between the cylinder 2 and the base 1 and the top cover 3. According to the needs, the handle 23 and the cylinder 2 can be fixedly installed by riveting or bonding or threaded fasteners or welding in the prior art. In this embodiment, the handle 23 can be a C-shaped handle.

[0036] Embodiment 7: As attached Figure 1 , 5 As shown, at least two wrench holes 25 with openings facing outward are evenly distributed along the circumference of the outer side of the lower part of the base 1 and the outer side of the upper part of the top cover 3. By setting it in this way, it is more convenient to realize the rapid disassembly and assembly of the base 1, the top cover 3 and the cylinder 2.

[0037] Embodiment 8: As attached Figure 5 As shown, the method of using the oil well carbon dioxide sampling device is carried out as follows: in the first step, the primary separator is connected to the gas outlet of the existing wellhead sampler through the air pipe and the air nozzle, and then the primary separator is connected to the separation sampler through the air inlet pipe 8, and then the gas measuring valve 11 is connected to the gas detector, and the sampling valve 10 is connected to the sampling bag; in the second step, the sampling valve 10 on the sampler is opened, and the oil and gas samples enter the separation bottle 17 of the primary separator from the oil discharge port of the sampler for pressure reduction and preliminary separation; in the third step, the oil and gas samples after preliminary separation reach the separation chamber 5 of the separation sampler through the air inlet pipe 8, and the oil and gas samples hit the blind plate when spraying out for secondary separation, and the separated oil flows into the bottom of the cylinder 2, and the separated gas sample enters the exhaust chamber 6 through the filter hole 16, and finally the gas samples reach the gas detector for detection and the sampling bag for collection and sampling.

[0038] The above-mentioned sampling method is used to sample the oil and gas samples flowing out of the air outlet of the existing sampler. By increasing the spatial volume of the sampling device, two-stage pressure reduction separation can be achieved, so that the oil and gas separation in the oil and gas sample is more thorough. When the separated gas passes through the filter hole 16, the residual oil and gas in the oil and gas sample can be further separated under the throttling and pressure reduction and adsorption effects of the filter hole 16, so that the gas sample has higher purity and is more in line with the sampling standard, and high-pressure gas leakage and injection pollution detection instruments can be prevented. The constant pressure vent valve 21 can effectively prevent pressure buildup in the cylinder and avoid sampling safety hazards. The oil and gas sample is always in a sealed state during the process of flowing through the primary separator and the separation sampler, which can effectively prevent the gas sample from being disturbed by air and effectively ensure the accuracy of carbon dioxide concentration detection.

[0039] The above technical features constitute the embodiments of the present invention, which have strong adaptability and implementation effect. Non-essential technical features can be added or reduced according to actual needs to meet the requirements of different situations.

Claims

1. An oil well carbon dioxide sampling device, characterized in that It includes a primary separator and a separation sampler. The separation sampler includes a base, a cylinder, a top cover and a partition assembly. The top cover and the base are detachably installed on the inner sides of the upper end and the lower end of the cylinder respectively. Slots are provided on the inner sides of the front and rear of the cylinder corresponding to the upper side of the base. A partition assembly is inserted in the slot corresponding to the position below the top cover. The partition assembly divides the inner side of the cylinder into a separation chamber and an exhaust chamber on the left and right sides. An air inlet is provided on the cylinder corresponding to the upper left side of the separation chamber. An air inlet pipe is fixedly installed in the air inlet. A primary separator capable of performing preliminary pressure reduction and separation on oil and gas samples is detachably installed on the other end of the air inlet pipe. A sampling port and an exhaust port are provided on the cylinder corresponding to the upper part of the exhaust chamber at intervals in front and back. A sampling valve is fixedly installed in the sampling port, and a gas measuring valve is fixedly installed in the exhaust port.

2. The oil well carbon dioxide sampling device according to claim 1, characterized in that The partition assembly includes a filter partition and a handle. The filter partition is inserted into the slot corresponding to the position below the top cover. The filter partition includes a blind plate portion, a filter portion and a bending portion. The filter partition corresponding to the air inlet position is the blind plate portion. The filter plate corresponding to the sampling port and the position above the exhaust port is bent toward one side of the exhaust cavity to form a bending portion that can block the exhaust cavity. A handle is fixedly installed on the upper side of the bending portion. The filter partition corresponding to the blind plate portion and the outer side of the bending portion is the filtering portion. The filtering portion is provided with a plurality of filter holes that pass through from left to right.

3. The oil well carbon dioxide sampling device according to claim 1 or 2, characterized in that The primary separator includes a separation bottle, a bottle cap, an air inlet joint and an air outlet joint. The bottle cap is sealed on the upper end of the separation bottle, and the bottle cap is provided with air inlet holes and air outlet holes that can connect the inside and outside of the separation bottle at intervals. An air inlet joint is provided on the side of the air inlet hole connected to the outside world, and an air outlet joint is provided on the side of the air outlet hole connected to the outside world. The other end of the air outlet joint is detachably installed together with the air inlet pipe.

4. The oil well carbon dioxide sampling device according to claim 1 or 2, characterized in that The separation sampler also includes a constant-pressure air release valve. A pressure relief hole which passes through from top to bottom is arranged in the middle of the top cover, and a constant-pressure air release valve is arranged in the pressure relief hole.

5. The oil well carbon dioxide sampling device according to claim 3, characterized in that The separation sampler also includes a constant-pressure air release valve. A pressure relief hole which passes through from top to bottom is arranged in the middle of the top cover, and a constant-pressure air release valve is arranged in the pressure relief hole.

6. The oil well carbon dioxide sampling device according to claim 1, 2 or 5, characterized in that An oil collecting groove with an opening facing upward is arranged on the upper side of the base, and the lower part of the partition assembly is located in the oil collecting groove.

7. The oil well carbon dioxide sampling device according to claim 3, characterized in that An oil collecting groove with an opening facing upward is arranged on the upper side of the base, and the lower part of the partition assembly is located in the oil collecting groove.

8. The oil well carbon dioxide sampling device according to claim 4, characterized in that An oil collecting groove with an opening facing upward is arranged on the upper side of the base, and the lower part of the partition assembly is located in the oil collecting groove.

9. The oil well carbon dioxide sampling device according to claim 1 or 2 or 5 or 7 or 8, characterized in that The separation sampler also includes a handle and a sealing ring. A handle is fixedly installed on the outer side of the front part of the cylinder, and sealing rings are provided between the inner side of the upper end of the cylinder and the outer side of the lower part of the cover, and between the inner side of the lower end of the cylinder and the outer side of the upper part of the base; or / and, the outer side of the lower part of the base and the outer side of the upper part of the top cover are evenly distributed along the circumference with at least two wrench holes opening outward.

10. A method for using the oil well carbon dioxide sampling device according to any one of claims 3 to 9, characterized in that Proceed as follows: first, connect the primary separator to the gas outlet of the existing wellhead sampler through a soft air pipe and an air nozzle, then connect the primary separator to the separation sampler through an air inlet pipe, then connect the gas measuring valve to the gas detector, and connect the sampling valve to the sampling bag; second, open the sampling valve on the sampler, and the oil and gas samples enter the separation bottle of the primary separator from the oil drain port of the sampler for pressure reduction and preliminary separation; third, the oil and gas samples after preliminary separation reach the separation chamber of the separation sampler through the air inlet pipe, and the oil and gas samples hit the blind plate when spraying out for secondary separation, and the separated oil flows into the bottom of the cylinder, and the separated gas sample enters the exhaust chamber through the filter hole, and finally the gas samples reach the gas detector for detection and the sampling bag for collection and sampling.

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