Crude oil single well sampling device and sampling method

Abstract

The invention discloses a crude oil single well sampling device and a sampling method. The sampling device comprises an oil chamber assembly and a gas chamber assembly; the oil chamber assembly comprises a bottom plate, an outer shell is arranged on the bottom plate, an inner shell is arranged in the outer shell, and a plurality of guide plates are arranged on the inner wall of the inner shell; the top of the outer shell is connected with a top connecting pipe, and the bottom of the outer shell is connected with a bottom connecting pipe; the air chamber assembly comprises an air chamber shell, the bottom of the air chamber shell is connected with a sampling connecting pipe, and a connecting pipe is connected between the top connecting pipe and the sampling connecting pipe. The oil chamber assembly and the gas chamber assembly cooperate with each other to achieve convenient collection and sampling of sample gas, meanwhile, the heat preservation plate and the bottom heat preservation plate are used for internal heat preservation of the device, the mirror surface coating is used for heat preservation outside, and the heat preservation performance of the device is improved through double heat preservation measures; therefore, wax is prevented from separating out from crude oil to form solid wax crystals to block a pipeline, and stable use of the device is guaranteed.

Description

Technical Field

[0001] This invention relates to the field of single-well sampling, and in particular to a crude oil single-well sampling device and sampling method. Background Technology

[0002] With the continuous increase in the development of offshore oil and gas resources in my country, offshore oil fields have become an important energy production base for the country. In the production process of offshore oil fields, accurate and timely acquisition of various parameters of oil well production is crucial for reservoir dynamic analysis, production optimization, well condition diagnosis, and safe production. Single-well metering and sampling are key steps in obtaining these parameters.

[0003] In existing technologies, sampling methods typically require the temporary installation of sampling devices on pipelines through which multiphase flow occurs, or special measures to be taken at the wellhead for sampling. These methods are complex to operate, time-consuming, and easily affected by human factors during the sampling process, resulting in poor gas sample representativeness and difficulty in accurately reflecting the true composition of downhole gas. In addition, oil well formations at depth usually have high temperatures and pressures. When waxy crude oil is extracted from the formation and rises to the wellhead, the temperature gradually decreases. The solubility of wax in crude oil decreases with decreasing temperature. When the temperature is below the wax precipitation point (also known as the cloud point), the wax will precipitate from the crude oil, forming solid wax crystals, affecting single-well sampling and test results. Therefore, a new type of crude oil single-well sampling device and sampling method is needed to meet these needs. Summary of the Invention

[0004] In order to solve the problems of difficulty in obtaining gas samples and oil sample wax precipitation clogging the equipment in the prior art, the present invention provides a crude oil single-well sampling device and sampling method.

[0005] In a first aspect, the present invention provides a crude oil single-well sampling device, which is achieved by the following technical solution.

[0006] A crude oil single-well sampling device includes an oil chamber assembly and a gas chamber assembly; The oil chamber assembly includes a base plate, an outer shell on the base plate, an inner shell inside the outer shell, and several guide plates on the inner wall of the inner shell; the top of the outer shell is connected to a top connecting pipe, and the bottom of the outer shell is connected to a bottom connecting pipe. The gas chamber assembly includes a gas chamber shell, a sampling connection tube connected to the bottom of the gas chamber shell, and a connection tube connecting the top connection tube and the sampling connection tube.

[0007] Furthermore, the top connecting pipe is equipped with a first switching valve and a second switching valve; the bottom connecting pipe is equipped with a third switching valve and a fourth switching valve; the sampling connecting pipe is equipped with a fifth switching valve and a sixth switching valve; and the two ends of the connecting pipe are respectively connected to the second switching valve and the fifth switching valve.

[0008] Furthermore, an insulation board is provided between the outer shell and the inner shell; a bottom insulation board is provided between the bottom plate and the bottom surface of the inner shell.

[0009] Furthermore, the outer side of the outer shell is coated with a mirror coating, which is a titanium oxide / gold nano-coating with a thickness of 5-20 nanometers.

[0010] Furthermore, several guide vanes are alternately arranged at an angle downwards on the inner wall of the inner casing.

[0011] Furthermore, the inner surface of the inner shell and the guide plate are provided with an oleophobic layer, which has a horizontal stripe structure of corn husk.

[0012] Furthermore, a piston rod is provided inside the air chamber housing, and the bottom end of the piston rod is connected to a movable disk, which is in contact with the inner wall of the air chamber housing.

[0013] Furthermore, a handle is rotatably connected to the top of the outer housing.

[0014] Secondly, the present invention provides a crude oil single-well sampling method, which is achieved by the following technical solution.

[0015] A crude oil single-well sampling method, using the aforementioned crude oil single-well sampling device, includes the following steps: S1. In the initial stage, all switch valves are kept closed to purge the oil chamber assembly. Connect the third switch valve to the oil well to be sampled, and then open the third switch valve and the first switch valve. The mixed gas in the oil chamber assembly is gradually emptied by the pressure of the sampling gas itself. S2. During the venting process, a handheld gas detector is used at the first switch valve to pre-detect the toxic gases hydrogen sulfide, sulfur dioxide, and carbon monoxide in the oil well. If the toxic gas content in the gas sample is within the safe range, the subsequent steps are carried out. If the toxic gas content exceeds the standard, the sampling of the oil well is temporarily suspended. S3. After 15 minutes of replacement, open the second and fifth switch valves and close the first switch valve to introduce the pure sample gas into the gas chamber assembly. The sample gas will fill the gas chamber assembly under its own pressure, lifting the piston rod and the movable plate. S4. Close the first, second, third, fourth, and fifth switch valves, disconnect the connecting pipe, connect the sixth switch valve to the gas detection equipment through the pipeline, and then open the sixth switch valve. Use the piston rod and movable disc to push the sampled gas to the gas detection equipment.

[0016] Furthermore, in step S2, if the flow rate of natural gas flowing out of the oil chamber assembly from the crude oil is lower than the flow rate of crude oil entering the oil chamber assembly from a single well, the fourth switch valve is opened to appropriately discharge the liquid from the oil chamber assembly.

[0017] This application has the following beneficial effects: This invention utilizes the cooperation of oil chamber components and gas chamber components to achieve convenient collection and sampling of sample gases. At the same time, it uses insulation boards and bottom insulation boards for internal insulation of the equipment, while using a mirror coating for external insulation. The use of dual insulation measures improves the insulation performance of the device, thereby preventing wax from precipitating from crude oil and forming solid wax crystals that block the pipeline, and ensuring the stable use of the device.

[0018] The device of this invention has a simple structure and is easy to maintain. After use, it can be reused after maintenance and cleaning, thereby further reducing the cost of using the device. At the same time, the Tesla valve-like structure composed of the internal guide plates can ensure that gas is transported upward and liquid is discharged downward, avoiding liquid or gas being discharged in the wrong position. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of the present invention; Figure 2 This is a side view of the structure of the present invention; Figure 3 This is a schematic diagram of the structure of the air chamber assembly of the present invention; Figure 4 This is a schematic diagram of the structure of the oil chamber assembly of the present invention; Figure 5 This is a flowchart illustrating the sampling method of the present invention.

[0020] Among them, 100 is the base plate; 101 is the outer shell; 102 is the inner shell; 103 is the guide plate; 104 is the insulation plate; 105 is the bottom insulation plate; 106 is the oleophobic layer; 107 is the handle; 108 is the mirror coating; 200 is the top connecting pipe; 201 is the first switching valve; 202 is the second switching valve; 203 is the bottom connecting pipe; 204 is the third switching valve; 205 is the fourth switching valve; 206 is the sampling connecting pipe; 207 is the fifth switching valve; 208 is the sixth switching valve; 300 is the air chamber shell; 301 is the piston rod; 302 is the movable disc; and 400 is the connecting pipe. Detailed Implementation

[0021] The present patent application will be further described below with reference to the accompanying drawings and embodiments.

[0022] Reference Figure 1-4 A crude oil single-well sampling device, comprising an oil chamber assembly and a gas chamber assembly.

[0023] The oil chamber assembly includes a base plate 100, an outer shell 101 fixedly installed on the base plate 100, an inner shell 102 fixedly installed inside the outer shell 101, a guide plate 103 fixedly installed on the inner wall of the inner shell 102, a top connecting pipe 200 fixedly installed on the top of the outer shell 101, and a bottom connecting pipe 203 fixedly installed on the bottom of the outer shell 101.

[0024] The gas chamber assembly includes a gas chamber shell 300, a sampling connection pipe 206 is arranged on the bottom side of the gas chamber shell 300, and a connection pipe 400 is connected between the top connection pipe 200 and the sampling connection pipe 206. The oil chamber assembly and the gas chamber assembly cooperate to realize the convenient collection and sampling of sample gas.

[0025] In an optional embodiment: a first switching valve 201 and a second switching valve 202 are arranged on the top connecting pipe 200, a third switching valve 204 and a fourth switching valve 205 are arranged on the bottom connecting pipe 203, a fifth switching valve 207 and a sixth switching valve 208 are arranged on the sampling connecting pipe 206, and the two ends of the connecting pipe 400 are respectively connected to the second switching valve 202 and the fifth switching valve 207.

[0026] In an optional embodiment: an insulation board 104 is arranged between the outer shell 101 and the inner shell 102, and a bottom insulation board 105 is arranged between the bottom plate 100 and the bottom surface of the inner shell 102.

[0027] The present invention uses insulation plate 104 and bottom insulation plate 105 to isolate between outer shell 101 and inner shell 102, thereby reducing the loss of internal temperature, ensuring the stable temperature of crude oil filled in inner shell 102, and preventing wax precipitation of crude oil due to temperature drop, which would block the internal pipeline passage.

[0028] In an optional embodiment: the outer side of the outer shell 101 is coated with a mirror coating 108, which is a titanium oxide / gold nano-coating with a thickness of 5-20 nanometers.

[0029] The present invention utilizes the mirror coating 108 to reflect infrared thermal radiation, thereby reducing the heat in the inner shell 102 through thermal radiation.

[0030] This invention utilizes both insulation boards and bottom insulation boards for internal insulation of the equipment, while using a mirror coating for external insulation. This dual insulation measure improves the insulation performance of the device, thereby preventing wax from precipitating from crude oil and forming solid wax crystals that block the pipes, ensuring the stable operation of the device.

[0031] In an optional embodiment, an oleophobic layer 106 is disposed on the inner surface of the inner housing 102 and the guide plate 103, the oleophobic layer 106 being a corn husk horizontal stripe structure (HNP coating).

[0032] The present invention utilizes an oleophobic layer 106 to reduce the adhesion of crude oil to the inner surface of the inner shell 102 and the guide plate 103, thereby preventing the accumulation of crude oil from affecting normal gas flow and crude oil discharge.

[0033] Furthermore, considering both layout cost and radiation control efficiency, the mirror coating 108 of this invention uses a titanium dioxide / gold nano-coating (flower-shaped TiO2@Au core-shell structure gold-titanium dioxide nanocomposite material, purchased from Xi'an Qiyue Biotechnology, with an infrared absorption rate >90%); the oleophobic layer 106 uses a corn husk horizontal stripe structure (using 8D027DC Warnerco nano-coating, prepared by spray printing process, with a sliding angle <5° (crude oil), high wear resistance (no peeling after 100 wear cycles), and resistance to salt spray and ultraviolet radiation) to consider both layout cost and mechanical stability. Since the device of this invention needs to be reusable and has limited internal space, the durability of the materials is prioritized to reduce subsequent maintenance costs.

[0034] In an optional embodiment: a piston rod 301 is slidably installed inside the air chamber housing 300, and a movable disk 302 is fixedly installed at the bottom of the piston rod 301, with the movable disk 302 in contact with the inner wall of the air chamber housing 300.

[0035] The piston rod 301 of this invention can drive the movable disk 302 to slide within the gas chamber housing 300. Conversely, the increase in gas within the gas chamber housing 300 can also drive the movable disk 302 and piston rod 301 to move. The movable disk 302 and piston rod 301 cooperate with each other to achieve gas sample collection.

[0036] In an alternative embodiment, a handle 107 is rotatably mounted on the top of the outer housing 101.

[0037] like Figure 5 As shown, the present invention also provides a method for crude oil single-well sampling using the above-mentioned crude oil single-well sampling device, specifically as follows: S1. In the initial stage, all switching valves are kept closed to purge the oil chamber assembly. The third switching valve 204 is connected to the oil well to be sampled. Then, the third switching valve 204 and the first switching valve 201 are opened slightly to gradually purge the mixed gas in the oil chamber assembly by the pressure of the sampling gas itself. S2. During the venting process, a handheld gas detector can be used at the first switch valve 201 to "pre-detect" toxic gases such as hydrogen sulfide, sulfur dioxide, and carbon monoxide in the oil well. If the content of toxic gases in the gas sample is within the safe range, the subsequent steps will be carried out. If the content of toxic gases exceeds the standard, the sampling of the oil well will be temporarily suspended. S3. After 15 minutes of replacement, open the second switch valve 202 and the fifth switch valve 207, and close the first switch valve 201. Introduce the pure sample gas into the gas chamber assembly. The sample gas will fill the gas chamber assembly under its own pressure, lifting the piston rod 301 and the movable plate 302. S4. Close the first switch valve 201, the second switch valve 202, the third switch valve 204, the fourth switch valve 205, and the fifth switch valve 207. Disconnect the connecting pipe 400. After connecting the sixth switch valve 208 to the gas detection equipment through the pipeline, open the sixth switch valve 208. Use the piston rod 301 and the movable plate 302 to push the sampled gas to the gas detection equipment.

[0038] In an optional embodiment: In step S2, if the flow rate of natural gas flowing out of the oil chamber component from the crude oil is lower than the flow rate of crude oil entering the oil chamber component from a single well, that is, the crude oil level in the oil chamber component rises too fast, the fourth switch valve 205 can be opened appropriately to drain the liquid in the oil chamber component in order to control the crude oil level in the oil chamber component.

[0039] The embodiments described herein are preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Therefore, all equivalent changes made in accordance with the structure, shape, and principle of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A crude oil single-well sampling device, characterized in that: Includes oil chamber components and gas chamber components; The oil chamber assembly includes a base plate (100), an outer shell (101) on the base plate (100), an inner shell (102) inside the outer shell (101), and a plurality of guide plates (103) on the inner wall of the inner shell (102); the top of the outer shell (101) is connected to a top connecting pipe (200), and the bottom of the outer shell (101) is connected to a bottom connecting pipe (203). The air chamber assembly includes an air chamber housing (300), a sampling connection tube (206) connected to the bottom of the air chamber housing (300), and a connection tube (400) connecting the top connection tube (200) and the sampling connection tube (206).

2. The crude oil single-well sampling device according to claim 1, characterized in that: The top connecting pipe (200) is provided with a first switching valve (201) and a second switching valve (202); the bottom connecting pipe (203) is provided with a third switching valve (204) and a fourth switching valve (205); the sampling connecting pipe (206) is provided with a fifth switching valve (207) and a sixth switching valve (208); the two ends of the connecting pipe (400) are respectively connected to the second switching valve (202) and the fifth switching valve (207).

3. The crude oil single-well sampling device according to claim 1, characterized in that: An insulation board (104) is provided between the outer shell (101) and the inner shell (102); a bottom insulation board (105) is provided between the bottom plate (100) and the bottom surface of the inner shell (102).

4. The crude oil single-well sampling device according to claim 1, characterized in that: The outer shell (101) is coated with a mirror coating (108) on its outer side. The mirror coating (108) is a titanium oxide / gold nano-coating with a thickness of 5-20 nanometers.

5. A crude oil single-well sampling device according to claim 1, characterized in that: Several guide plates (103) are alternately arranged on the inner wall of the inner shell (102) at an angle downwards.

6. The crude oil single-well sampling device according to claim 1, characterized in that: The inner surface of the inner shell (102) and the guide plate (103) are provided with an oleophobic layer (106), which is a horizontal stripe structure of corn husk.

7. A crude oil single-well sampling device according to claim 1, characterized in that: The gas chamber housing (300) is provided with a piston rod (301), the bottom end of which is connected to a movable disk (302), and the movable disk (302) is in contact with the inner wall of the gas chamber housing (300).

8. A crude oil single-well sampling device according to claim 1, characterized in that: The top of the outer housing (101) is rotatably connected to the handle (107).

9. A method for crude oil single-well sampling, characterized in that: The crude oil single-well sampling device according to any one of claims 1-8 includes the following steps: S1. In the initial stage, all switch valves are kept closed to purge the oil chamber assembly. The third switch valve (204) is connected to the oil well to be sampled. Then, the third switch valve (204) and the first switch valve (201) are opened to gradually purge the mixed gas in the oil chamber assembly by the pressure of the sampling gas itself. S2. During the venting period, a handheld gas detector is used at the first switch valve (201) to pre-detect the toxic gases hydrogen sulfide, sulfur dioxide, and carbon monoxide in the oil well. If the content of toxic gases in the gas sample is within the safe range, the subsequent steps are carried out. If the content of toxic gases exceeds the standard, the sampling of the oil well is temporarily suspended. S3. After 15 minutes of replacement, open the second switch valve (202) and the fifth switch valve (207), and close the first switch valve (201) to input the pure sample gas into the gas chamber assembly. The sample gas will fill the gas chamber assembly under its own pressure, lifting the piston rod (301) and the movable plate (302). S4. Close the first switch valve (201), the second switch valve (202), the third switch valve (204), the fourth switch valve (205), and the fifth switch valve (207), disconnect the connecting pipe (400), connect the sixth switch valve (208) to the gas detection equipment through the pipeline, and then open the sixth switch valve (208). Use the piston rod (301) and the movable plate (302) to push the sampled gas to the gas detection equipment.

10. The crude oil single-well sampling method according to claim 9, characterized in that: In S2, if the flow rate of natural gas from the oil chamber component is lower than the flow rate of crude oil entering the oil chamber component from a single well, the fourth switch valve (205) is opened to appropriately discharge the liquid from the oil chamber component.

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