Heavy oil natural gas blending cold production device based on plunger pump oil extraction and use method
By separating and pressurizing natural gas on the ground, the problem of dependence on external resources for heavy oil extraction has been solved, achieving efficient and low-carbon cold extraction of heavy oil and reducing resource consumption and costs.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SHANDONG PETROCHEMICAL INST
- Filing Date
- 2026-06-09
- Publication Date
- 2026-07-10
AI Technical Summary
Existing heavy oil extraction technologies rely on external light oil or natural gas resources, resulting in high resource consumption and increased costs. Furthermore, heavy oil wells with low plunger pumping efficiency cannot be effectively cold-extracted.
By adding an oil-gas separation device on the surface, natural gas is separated from the extracted oil. After being pressurized by a booster pump, it is injected into the plunger pump barrel downhole to mix with heavy oil to reduce viscosity. Then, it is discharged to the surface through the oil pipe for gas-liquid separation, thus realizing cold extraction of heavy oil.
It reduced natural gas consumption, improved heavy oil extraction efficiency, met the oil production needs of small-displacement heavy oil wells, and achieved the goal of low-carbon extraction.
Smart Images
Figure CN122358993A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of heavy oil low-carbon development technology, and in particular to a heavy oil cold extraction device and its method of use based on plunger pump oil extraction and blending with natural gas. Background Technology
[0002] In the petroleum industry, heavy oil is difficult to extract due to its high viscosity and poor fluidity. There are two main methods for extracting heavy oil: The first is thermal extraction, which reduces viscosity through heating. This involves injecting high-temperature, high-pressure steam into the oil well. The steam then enters the heavy oil reservoir, and the well is left to simmer for several days to allow the heat from the steam to dissipate before the well is opened for oil extraction. However, this method is prone to problems such as steam leakage and a decrease in the oil-steam ratio in the later stages. It also has high development costs, requires heating for transportation, and has high energy consumption. Furthermore, the high-temperature, high-pressure steam poses safety hazards during operation. The second method is cold extraction, which involves mixing light oil or natural gas into the heavy oil to directly reduce the overall viscosity and improve its fluidity. For example, our team applied for Chinese patent number 202110859238X, entitled "A Device and Method for Continuously Injecting Light Oil to Achieve Cold Extraction of Heavy Oil." The technical solution is as follows: a double-layer injection isolation pipe is connected to the lower end of the pump barrel; an injection suction distributor is connected to the lower end of the double-layer isolation pipe; a suction floating ball is installed inside the double-layer isolation pipe; an injection diluent is connected to the lower end of the injection suction distributor; a multi-functional constant pressure isolation plate is installed in the lower part of the inner cavity of the injection suction distributor; a packer seat pressure plate is installed in the upper part of the inner cavity of the packer; and a pump plunger is installed inside the pump barrel. The beneficial effects are: there is no risk of burns during construction; because a cold extraction process for heavy oil is used, the risk of pipeline blockage due to temperature drop during gathering and transportation of extracted heavy oil is also avoided; the dilution source uses light oil, which can be continuously injected, and compared with chemical dilution sources, light oil is more abundant and less expensive. However, the problem is that it relies on a sufficient supply of external light oil. Although the injected light oil can eventually be extracted, it still requires oil refining to obtain light oil, thus consuming certain resources.
[0003] In addition, our team has applied for Chinese patent number 2026102676257, entitled "A Device and Method for Cold Extraction of Heavy Oil by Injecting Natural Gas into Continuous Tubing." The technical solution is as follows: the upper end of the continuous tubing is connected to a natural gas storage tank via a gas booster pump, and the other end is lowered into the production tubing and connected to a pneumatic production pump. A gas-liquid separator is connected to one side of the wellhead on the surface. The lower side of the gas-liquid separator is connected to the oil pipeline, and the upper part is connected to the upper side of the natural gas storage tank. Natural gas, after being pressurized, is injected downhole along the continuous tubing. The pneumatic production pump then extracts the oil to the gas-liquid separator on the surface. After separation, the natural gas is recycled, and the separated oil enters the oil pipeline. The beneficial effects of this invention are: firstly, it utilizes the property of natural gas to reduce the viscosity of heavy oil to achieve cold extraction; secondly, it utilizes the ability of natural gas to help lift the liquid upwards, thereby improving oil extraction efficiency and reducing the cost of cold extraction of heavy oil. However, there are some problems: on the one hand, it relies on external natural gas resources and consumes a lot of natural gas; on the other hand, the invention uses a pneumatic oil pump, which can achieve large-volume heavy oil extraction, but it cannot be used for some heavy oil wells with low production that can only be pumped by plunger pumps.
[0004] Furthermore, since natural gas is usually associated with oil extraction, or natural gas is dissolved in the extracted oil, how to utilize the natural gas in the extracted oil, separate it, and then recycle it into the production string downhole can reduce the viscosity of the heavy oil in the string. This would eliminate the need for large amounts of natural gas to be injected downhole, not only reducing natural gas consumption and improving extraction efficiency, but also meeting the needs of small-displacement heavy oil wells using plunger pumps. Summary of the Invention
[0005] The purpose of this invention is to address the aforementioned deficiencies in existing technologies by providing a cold extraction device and method for heavy oil mixed with natural gas based on plunger pump oil extraction. By adding an oil-gas separation device on the surface, natural gas is separated from the extracted oil. Then, the natural gas is pressurized by a booster pump and injected into the oil pump barrel of the plunger pump downhole through a gas mixing valve. This allows the natural gas to continuously mix with the pumped heavy oil, reducing viscosity. Finally, the oil is discharged through a tubing to the oil-gas separation device on the surface to separate the natural gas, thus achieving cold extraction of heavy oil.
[0006] This invention discloses a heavy oil cold production device based on a plunger pump for blending natural gas. The technical solution includes: a pump barrel, a pump plunger, a sucker rod, a large four-way valve, a polished rod, and a polished rod seal. It also includes a single-pipe gas-blending valve, a produced fluid pipeline, a gas-liquid separator, a gas booster pump, a pressure reducing valve, a check valve, a circulating gas supply pipeline, and a pressure stabilizing tank. The single-pipe gas-blending valve is connected to the top of the pump barrel via an oil pipe. The inlet of the single-pipe gas-blending valve is connected to the circulating gas supply pipeline, which runs along the oil pipe and casing. The annulus of the pipe is connected to a pressure stabilizing tank on one side of the wellhead. The liquid outlet of the large four-way valve on the wellhead is connected to the inlet of the gas-liquid separator through the produced liquid pipeline. The gas outlet of the gas-liquid separator is connected to a gas booster pump through a pipeline, and the inlet of the gas booster pump is connected in parallel to a natural gas supply pipeline. The outlet of the gas booster pump is connected to the pressure stabilizing tank through a pressure reducing valve. The lower outlet of the pressure reducing valve is connected to the pipeline at the outlet of the gas-liquid separator through a pipeline and a check valve. The liquid outlet of the gas-liquid separator is connected to an oil pipeline.
[0007] Preferably, the above-mentioned single-pipe gas mixing valve includes an upper connector, a one-way valve plug, a valve body, a spring, a lower connector, a gas mixing channel, and an oil discharge channel. The upper end of the valve body is connected to the upper connector, and the lower end is provided with a lower connector. A gas mixing channel is provided on the side wall of the upper connector. A conical valve seat is provided at the lower end of the gas mixing channel. The one-way valve plug is connected to the conical valve seat. A spring is installed at the lower end of the one-way valve plug. An oil discharge channel is provided at the center of the valve body.
[0008] Another type of heavy oil cold production device based on plunger pump oil extraction mentioned in this invention has the following technical solution: it includes a pump barrel, a pump plunger, a sucker rod, a large four-way valve, a polished rod, and a polished rod seal. It also includes a double-layer tubing gas-injection valve, a double-layer tubing, an inner tube connector, a compensator, a produced fluid pipeline, a gas-liquid separator, a gas booster pump, a pressure reducing valve, a check valve, a circulating gas supply pipeline, and a pressure stabilizing tank. The double-layer tubing gas-injection valve is installed at the upper end of the pump barrel, and its upper end is connected to the double-layer tubing via the inner tube connector. A compensator is installed at the upper middle end of the double-layer tubing. The inlet of the column gas-injection valve is connected to the circulating gas supply pipeline on one side of the wellhead via a double-layer tubing string. The circulating gas supply pipeline is then connected to the pressure stabilizing tank. The liquid outlet of the large four-way valve on the wellhead is connected to the inlet of the gas-liquid separator via the produced liquid pipeline. The gas outlet of the gas-liquid separator is connected to a gas booster pump via a pipeline, and the inlet of the gas booster pump is connected in parallel to a natural gas replenishment pipeline. The outlet of the gas booster pump is connected to the pressure stabilizing tank via a pressure reducing valve. The lower outlet of the pressure reducing valve is connected to the pipeline at the outlet of the gas-liquid separator via a pipeline and a check valve. The liquid outlet of the gas-liquid separator is connected to the oil pipeline.
[0009] Preferably, the above-mentioned double-layer tubular gas mixing valve includes a gas mixing valve conversion body, a sealing sleeve, a sealing piston, a second spring, a second gas mixing channel, a gas mixing valve body, and a gas mixing valve body inlet channel. The upper end of the gas mixing valve body is connected to the gas mixing valve conversion body, and the gas mixing valve body inlet channel is provided in the middle of the gas mixing valve body. A sealing sleeve is fitted on the outer wall of the middle part of the gas mixing valve body. The upper end of the sealing sleeve is connected to the outer wall of the gas mixing valve conversion body. A sealing piston and a second spring are installed in the cavity formed between the sealing sleeve and the outer wall of the gas mixing valve body. The second gas mixing channel in the axial direction is provided in the gas mixing valve conversion body. The opening and closing of the second gas mixing channel and the gas mixing valve body inlet channel are controlled by the sealing piston.
[0010] Preferably, the upper end of the gas mixing valve converter is movably connected to the outer tube of the double-layer column, and a locking spring is provided on the upper part of the inner wall of the gas mixing valve converter. The locking spring is movably connected to the inner tube connector to realize the movable connection of the inner tube of the double-layer column.
[0011] Preferably, the upper part of the inner wall of the above-mentioned gas mixing valve conversion body is provided with a support limiting seat. The support limiting seat has a conical structure and multiple sealing grooves and a locking spring are distributed inside. The support limiting seat is used to support the upper inner tube connector.
[0012] Preferably, the outer diameter of the above-mentioned gas mixing valve body is smaller than the outer diameter of the gas mixing valve conversion body, and the gas mixing valve body, the gas mixing valve conversion body and the support limiting seat are integrated into one structure. The outer walls of the gas mixing valve body and the gas mixing valve conversion body form a two-stage stepped structure. A sealing sleeve is installed at the outer step, and a sealing piston and a second spring are installed at the inner step and the cavity formed between the sealing sleeve and the outer wall of the gas mixing valve body.
[0013] Preferably, the aforementioned inner tube connector includes an upper connector, a safety shear pin, a connector body, a connector sealing ring, a connector groove, and a lower connector. The connector body has a cylindrical structure, and a lower connector is provided at the lower end of the connector body for connecting with a support limiting seat. A connector groove is provided on the lower outer wall of the connector body for movably connecting with the locking spring of the double-layer tubing aeration valve. The upper end of the connector body is connected to the upper connector via the safety shear pin and the connector sealing ring. The upper connector has an internal thread for connecting with the inner tube thread of the double-layer tubing.
[0014] The method of using the first type of heavy oil-natural gas blending cold recovery device based on plunger pump oil recovery mentioned in this invention includes the following process: First, the pump barrel and single-tube gas-injecting valve are lowered into the casing downhole via tubing. The inlet of the single-tube gas-injecting valve is connected to the circulating gas supply line, which is connected along the annulus of the tubing and casing to the outlet of the pressure stabilizing tank on the surface wellhead side. Then, the pump plunger is lowered into the pump barrel via the sucker rod. The upper end of the sucker rod is connected to the polished rod, and a polished rod seal is connected to the polished rod. At the surface wellhead, the liquid outlet of the large four-way valve is connected to the inlet of the gas-liquid separator via the produced liquid pipeline. The gas outlet of the gas-liquid separator is connected to a gas booster pump via a pipeline. The outlet of the gas booster pump is connected to the pressure stabilizing tank via a pressure reducing valve. The lower outlet of the pressure reducing valve is connected to the pipeline at the outlet of the gas-liquid separator via a pipeline and a check valve, releasing excess pressure to the inlet of the gas booster pump for reuse. The liquid outlet of the gas-liquid separator is connected to the oil pipeline. 2. Start the pumping unit, gas booster pump, and gas-liquid separator. The pumping unit plunger is moved by the polished rod and sucker rod. During the downward movement of the pumping unit plunger, the one-way valve plug of the single-tube gas-injection valve opens under reduced pressure, and natural gas enters the oil discharge channel along the gas-injection channel of the single-tube gas-injection valve. During the upward movement of the pumping unit plunger, the one-way valve plug of the single-tube gas-injection valve closes under increased pressure, and the gas-injection channel is closed. At this time, the heavy oil downhole is driven by the pumping unit plunger to move upward along the pumping unit barrel. During the upward movement, the natural gas and heavy oil are continuously mixed, reducing the viscosity of the heavy oil. The viscosity-reduced oil is discharged to the outlet of the large four-way valve at the wellhead, and then sent to the gas-liquid separator for gas-liquid separation along the produced liquid pipeline. The separated natural gas is then sent to the pressure stabilizing tank by the gas booster pump. If the separated natural gas is insufficient, sufficient natural gas is added to the gas booster pump through the natural gas replenishment pipe, and the separated liquid is sent to the oil pipeline. Third, as the plunger of the oil pump moves alternately downward and upward, natural gas is continuously fed into the inner cavity of the oil pump barrel. In the inner cavity of the oil pump barrel, it mixes with heavy oil to reduce viscosity, thus realizing a cyclic heavy oil viscosity reduction extraction process.
[0015] The second method of using a heavy oil-natural gas blending cold recovery device based on a plunger pump, mentioned in this invention, includes the following steps: First, the pump barrel and the double-layer tubing injection valve are lowered into the casing downhole via the outer tube of the double-layer tubing string. A compensator is connected to the upper middle part of the outer tube. Then, the inner tube of the double-layer tubing string is lowered, with its lower end connected to an inner tube connector. The lower connector of the inner tube connector is inserted into the support limit seat of the double-layer tubing injection valve, and then secured in the connector groove by a locking spring, thus completing the installation connection between the inner tube and the double-layer tubing injection valve. Next, the pump barrel is lowered into the casing downhole via the sucker rod connected to the pump plunger. The upper end of the sucker rod is connected to the polished rod, and a polished rod is connected to the polished rod. The wellhead's four-way valve at the surface is connected to the inlet of the gas-liquid separator via a produced fluid pipeline. The gas outlet of the gas-liquid separator is connected to a gas booster pump via a pipeline. The outlet of the gas booster pump is connected to a pressure stabilizing tank via a pressure reducing valve. The outlet of the pressure stabilizing tank is connected to the inlet of the four-way valve via a circulating gas supply pipeline. The lower outlet of the pressure reducing valve is connected to the outlet pipeline of the gas-liquid separator via a pipeline and a check valve to release excess pressure to the inlet of the gas booster pump for reuse. The liquid outlet of the gas-liquid separator is connected to an oil pipeline. 2. Start the pumping unit, gas booster pump, and gas-liquid separator. The sucker rod and polished rod drive the pumping unit plunger. During the downward movement of the plunger, the sealing piston of the double-walled tubing mixing valve opens under the negative pressure inside the pump barrel. Natural gas enters the pump barrel through the double-walled tubing, the second mixing channel of the mixing valve, and the inlet channel of the mixing valve body. During the upward movement of the plunger, the sealing piston of the double-walled tubing mixing valve closes under the increased pressure, and the second mixing channel closes. During this process, the heavy oil in the well is driven upward along the pump barrel by the plunger of the pump. During the upward movement, the natural gas mixed with the heavy oil is continuously mixed, which reduces the viscosity of the heavy oil. The viscosity-reduced oil is discharged to the liquid outlet of the large four-way valve at the wellhead, and then sent to the gas-liquid separator for gas-liquid separation along the produced liquid pipeline. The separated natural gas is then sent to the pressure stabilizing tank through the gas booster pump. If the separated natural gas is insufficient, sufficient natural gas is added to the gas booster pump through the natural gas replenishment pipe, and the separated liquid is sent into the oil pipeline. Third, as the plunger of the oil pump moves alternately downward and upward, natural gas is continuously fed into the inner cavity of the oil pump barrel. In the inner cavity of the oil pump barrel, it mixes with heavy oil to reduce viscosity, thus realizing a cyclic heavy oil viscosity reduction extraction process.
[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: I. This invention involves adding an oil-gas separation device on the ground to separate natural gas from the extracted oil. The separated natural gas is then pressurized together with natural gas from pipelines or storage tanks by a booster pump. The pressurized natural gas is then sent through pipelines to a single-tube or double-tube gas-injection valve above the downhole plunger pump. As the plunger moves up and down, the single-tube or double-tube gas-injection valve opens when the plunger moves down, injecting natural gas into the pump barrel on the plunger pump. When the plunger moves up, the single-tube or double-tube gas-injection valve closes, and the plunger draws heavy oil from the casing into the pump barrel. This continuous mixing of the drawn-up heavy oil with the natural gas introduced during the plunger's downward movement reduces the viscosity of the heavy oil. The reduced-viscosity oil is then discharged to the surface through tubing and further separated by the surface oil-gas separation device for continued recycling, achieving cold extraction of heavy oil. 2. When the invention uses a double-layer tubing column with an air-mixing valve, the lower end of the outer tube of the double-layer tubing column is connected to the double-layer tubing column air-mixing valve and the oil pump barrel. The inner tube of the double-layer tubing column is connected through a specially designed inner tube connector. During installation, the inner tube is quickly connected by the connector body and the connector groove cooperating with the locking spring on the double-layer tubing column air-mixing valve. During disassembly, the lower end of the inner tube of the double-layer tubing column can be quickly disconnected from the double-layer tubing column air-mixing valve by unscrewing the safety shear pin, so that the subsequent operation of lifting the oil pump plunger can be carried out, which improves the efficiency of installation and disassembly. Third, this invention significantly reduces the amount of natural gas used by injecting natural gas into the downhole pump barrel instead of the casing. It also makes full use of the associated gas in the heavy oil extracted on-site. By adding a gas-liquid separator, the natural gas is separated from the oil and then circulated back into the downhole pump barrel, which reduces the viscosity of the heavy oil in the pump barrel. This eliminates the need for large amounts of natural gas to be injected downhole, reducing the consumption of natural gas resources, improving the extraction efficiency of heavy oil, and achieving the goal of low-carbon extraction of heavy oil. Attached Figure Description
[0017] Figure 1 This is an overall schematic diagram of the first embodiment of the present invention; Figure 2 This is a schematic diagram of a single-tube gas-injection valve; Figure 3 This is a schematic diagram showing the state when the single-tube gas-injecting valve is open for gas injection; Figure 4 This is an overall schematic diagram of the second embodiment of the present invention; Figure 5 This is a schematic diagram of the structure of the double-layer tubular gas-injecting valve of the present invention; Figure 6 This is a schematic diagram showing the state of the double-layer tubular column when the gas-injecting valve is open for gas injection. Figure 7This is a schematic diagram of the structure after the double-layer tubular aeration valve is connected to the inner tube connector; Figure 8 This is a schematic diagram of the inner tube connector of the present invention; Figure 9 This is a schematic diagram of the connection of the wellhead portion of the present invention; In the diagram: 1. Tubing; 2. Casing; 3. Pump barrel; 4. Pump plunger; 5. Single-tube gas injection valve; 6. Sucker rod; 7. Large four-way valve; 8. Polished rod; 9. Polished rod seal; 10. Produced fluid pipeline; 11. Gas-liquid separator; 12. Gas booster pump; 13. Pressure reducing valve; 14. Check valve; 15. Circulating gas supply pipeline; 16. Pressure stabilizing tank; 17. Double-layer tubing string; 18. Inner tube connector; 19. Compensator; 20. Double-layer tubing string gas injection valve; 21. Oil pipeline; 22. Natural gas replenishment pipeline. 5.1 Upper connector; 5.2 One-way valve plug; 5.3 Valve body; 5.4 Spring; 5.5 Lower connector; 5.6 Air mixing channel; 5.7 Oil discharge channel; 7.1 Air inlet; 7.2 Liquid outlet; 18.1 Upper connector of the connector; 18.2 Safety shear pin; 18.3 Connector body; 18.4 Connector sealing ring; 18.5 Connector slot; 18.6 Lower connector of the connector; 20.1 Upper conversion body of the gas mixing valve; 20.2 Sealing sleeve; 20.3 Locking spring; 20.4 Sealing piston; 20.5 Second spring; 20.6 Second gas mixing channel; 20.7 Gas mixing valve body; 20.8 Gas mixing valve body inlet channel; 20.9 Support limit seat. Detailed Implementation
[0018] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.
[0019] Example 1, referring to Figure 1The present invention discloses a heavy oil cold production device based on a plunger pump for blending natural gas, comprising a pump barrel 3, a pump plunger 4, a sucker rod 6, a large four-way valve 7, a polished rod 8, and a polished rod seal 9. It also includes a single-pipe gas-blending valve 5, a produced fluid pipeline 10, a gas-liquid separator 11, a gas booster pump 12, a pressure reducing valve 13, a one-way valve 14, a circulating gas supply pipeline 15, and a pressure stabilizing tank 16. The single-pipe gas-blending valve 5 is connected to the top of the pump barrel 3 via an oil pipe 1. The inlet of the single-pipe gas-blending valve 5 is connected to the circulating gas supply pipeline 15, and the circulating gas supply pipeline 15 runs along the annulus between the oil pipe 1 and the casing 2. A pressure stabilizing tank 16 is connected to the wellhead on the surface. The liquid outlet 7.2 of the large four-way valve 7 on the wellhead is connected to the inlet end of the gas-liquid separator 11 through the produced liquid pipeline 10. The gas outlet end of the gas-liquid separator 11 is connected to the gas booster pump 12 through a pipeline. The inlet end of the gas booster pump 12 is connected in parallel to the natural gas replenishment pipeline 22. The outlet of the gas booster pump 12 is connected to the pressure stabilizing tank 16 through the pressure reducing valve 13. The lower outlet of the pressure reducing valve 13 is connected to the pipeline at the outlet end of the gas-liquid separator 11 through a pipeline and a one-way valve 14. The liquid outlet end of the gas-liquid separator 11 is connected to the oil pipeline 21.
[0020] Reference Figure 2 and Figure 3 The single-pipe gas-injecting valve 5 mentioned in this invention includes an upper connector 5.1, a one-way valve plug 5.2, a valve body 5.3, a spring 5.4, a lower connector 5.5, a gas-injecting channel 5.6, and an oil discharge channel 5.7. The upper end of the valve body 5.3 is connected to the upper connector 5.1, and the lower end is provided with the lower connector 5.5. The gas-injecting channel 5.6 is provided on the side wall of the upper connector 5.1. The lower end of the gas-injecting channel 5.6 is provided with a conical valve seat. The one-way valve plug 5.2 is connected to the conical valve seat. The lower end of the one-way valve plug 5.2 is equipped with a spring 5.4. The center of the valve body 5.3 is provided with an oil discharge channel 5.7.
[0021] The method of using the heavy oil-natural gas blending cold recovery device based on plunger pump oil recovery mentioned in this invention includes the following process: First, the pump barrel 3 and the single-tube gas injection valve 5 are lowered into the casing 2 downhole via tubing 1. The air inlet of the single-tube gas injection valve 5 is connected to the circulating gas supply line 15. The circulating gas supply line 15 is connected along the annulus of tubing 1 and casing 2 to the outlet end of the pressure stabilizing tank 16 on the surface wellhead side. Then, the pump barrel 3 is lowered via the sucker rod 6 connected to the pump plunger 4. The upper end of the sucker rod 6 is connected to the polished rod 8, and the polished rod seal 9 is connected to the polished rod 8. The fluid outlet 7.2 is located at the large four-way connector 7 at the surface wellhead. The produced liquid pipeline 10 is connected to the inlet end of the gas-liquid separator 11. The gas outlet end of the gas-liquid separator 11 is connected to the gas booster pump 12 via a pipeline. The outlet of the gas booster pump 12 is connected to the pressure stabilizing tank 16 via a pressure reducing valve 13. The lower outlet of the pressure reducing valve 13 is connected to the pipeline at the outlet end of the gas-liquid separator 11 via a pipeline and a one-way valve 14 to release excess pressure to the inlet of the gas booster pump 12 for reuse. The liquid outlet end of the gas-liquid separator 11 is connected to the oil pipeline 21. 2. Start the pumping unit, gas booster pump 12, and gas-liquid separator 11. The sucker rod 8 and sucker rod 6 drive the pumping plunger 4 to move. During the downward movement of the pumping plunger 4, the one-way valve plug 5.2 of the single-tube gas-injection valve 5 opens under reduced pressure, allowing natural gas to enter the oil discharge channel 5.7 along the gas-injection channel 5.6 of the single-tube gas-injection valve 5. During the upward movement of the pumping plunger 4, the one-way valve plug 5.2 of the single-tube gas-injection valve 5 closes under increased pressure, and the gas-injection channel 5.6 closes. At this point, the heavy oil downhole is pumped out. The pump plunger 4 drives the oil pump barrel 3 upward. During the upward movement, the natural gas and heavy oil are continuously mixed, which reduces the viscosity of the heavy oil. The viscosity-reduced oil is discharged to the outlet port 7.2 of the large four-way valve 7 at the wellhead, and then sent to the gas-liquid separator 11 for gas-liquid separation along the produced liquid pipeline 10. The separated natural gas is then sent to the pressure stabilizing tank 16 through the gas booster pump 12. If the separated natural gas is insufficient, sufficient natural gas is added to the gas booster pump 12 through the natural gas replenishment pipe 22. The separated liquid is sent to the oil pipeline 21. Third, as the plunger 4 of the oil pump moves down and up alternately, natural gas is continuously fed into the inner cavity of the oil pump barrel 3, where it mixes with heavy oil to reduce viscosity, thus realizing a cyclic heavy oil viscosity reduction extraction process.
[0022] Example 2, refer to Figure 4Another type of heavy oil cold production device based on plunger pump oil extraction mentioned in this invention includes a pump barrel 3, a pump plunger 4, a sucker rod 6, a large four-way valve 7, a polished rod 8, and a polished rod sealer 9. It also includes a double-layer tubing gas-injection valve 20, a double-layer tubing 17, an inner tube connector 18, a compensator 19, a produced fluid pipeline 10, a gas-liquid separator 11, a gas booster pump 12, a pressure reducing valve 13, a one-way valve 14, a circulating gas supply pipeline 15, and a pressure stabilizing tank 16. The double-layer tubing gas-injection valve 20 is installed at the upper end of the pump barrel 3. The upper end of the double-layer tubing gas-injection valve 20 is connected to the double-layer tubing 17 via the inner tube connector 18. The compensator 19 is installed at the upper middle end of the double-layer tubing 17. The double-layer tubing gas-injection... The inlet of valve 20 is connected to the circulating gas supply line 15 on one side of the wellhead via a double-layer tubing string 17. The circulating gas supply line 15 is connected to the pressure stabilizing tank 16. The liquid outlet 7.2 of the large four-way valve 7 on the wellhead is connected to the inlet of the gas-liquid separator 11 via the produced liquid line 10. The gas outlet of the gas-liquid separator 11 is connected to the gas booster pump 12 via a pipeline. The inlet of the gas booster pump 12 is connected in parallel to the natural gas replenishment pipe 22. The outlet of the gas booster pump 12 is connected to the pressure stabilizing tank 16 via a pressure reducing valve 13. The lower outlet of the pressure reducing valve 13 is connected to the pipeline at the outlet of the gas-liquid separator 11 via a pipeline and a one-way valve 14. The liquid outlet of the gas-liquid separator 11 is connected to the oil pipeline 21.
[0023] Reference Figures 5-7 The double-layer tubular gas mixing valve 20 mentioned in this invention includes a gas mixing valve conversion body 20.1, a sealing sleeve 20.2, a sealing piston 20.4, a second spring 20.5, a second gas mixing channel 20.6, a gas mixing valve body 20.7, and a gas mixing valve body inlet channel 20.8. The upper end of the gas mixing valve body 20.7 is connected to the gas mixing valve conversion body 20.1, and the gas mixing valve body inlet channel 20.8 is provided in the middle of the gas mixing valve body 20.7. The outer wall of the middle part of the gas mixing valve body 20.7 is fitted with a gas mixing valve body conversion body 20.1. A sealing sleeve 20.2 is provided, the upper end of which is connected to the outer wall of the upper conversion body 20.1 of the gas mixing valve. A sealing piston 20.4 and a second spring 20.5 are installed in the cavity formed between the sealing sleeve 20.2 and the outer wall of the gas mixing valve body 20.1. An axial second gas mixing channel 20.6 is provided in the upper conversion body 20.1. The opening and closing of the second gas mixing channel 20.6 and the air inlet channel 20.8 of the gas mixing valve body are controlled by the sealing piston 20.4.
[0024] The upper end of the gas mixing valve conversion body 20.1 is movably connected to the outer tube of the double-layer column 17. The upper part of the inner wall of the gas mixing valve conversion body 20.1 is provided with a locking spring 20.3, which is movably connected to the inner tube connector 18 through the locking spring 20.3, so as to realize the movable connection of the inner tube of the double-layer column 17.
[0025] The upper part of the inner wall of the above-mentioned gas mixing valve conversion body 20.1 is provided with a support and limiting seat 20.9. The support and limiting seat 20.9 has a conical structure and multiple sealing grooves and a locking spring 20.3 are distributed inside. The support and limiting seat 20.9 is used to support the inner tube connector 18 above.
[0026] In addition, the outer diameter of the aforementioned gas-infusing valve body 20.7 is smaller than the outer diameter of the gas-infusing valve upper conversion body 20.1, and the gas-infusing valve body 20.7, the gas-infusing valve upper conversion body 20.1, and the support and limiting seat 20.9 are an integral structure, and the outer walls of the gas-infusing valve body 20.7 and the gas-infusing valve upper conversion body 20.1 form a two-stage stepped structure. A sealing sleeve 20.2 is installed at the outer step, and a sealing piston 20.4 and a second spring 20.5 are installed at the inner step and in the cavity formed between the sealing sleeve 20.2 and the outer wall of the gas-infusing valve body 20.7.
[0027] Reference Figure 8 The inner tube connector 18 mentioned in this invention includes an upper connector 18.1, a safety shear pin 18.2, a connector body 18.3, a connector sealing ring 18.4, a connector groove 18.5, and a lower connector 18.6. The connector body 18.3 has a cylindrical structure, and the lower connector 18.6 is provided at the lower end of the connector body 18.3 for connecting with the support limit seat 20.9. The connector groove 18.5 is provided on the lower outer wall of the connector body 18.3 for movably connecting with the locking spring 20.3 of the double-layer tube column aeration valve 20. The upper end of the connector body 18.3 is connected to the upper connector 18.1 through the safety shear pin 18.2 and the connector sealing ring 18.4. The upper connector 18.1 is provided with internal threads for connecting with the inner tube thread of the double-layer tube column 17.
[0028] The method of using the heavy oil-natural gas blending cold recovery device based on plunger pump oil recovery mentioned in this invention includes the following process: First, the pump barrel 3 and the double-layer tubing injection valve 20 are lowered into the casing 2 downhole via the outer tube of the double-layer tubing string 17. The upper middle part of the outer tube is connected to the compensator 19. Then, the inner tube of the double-layer tubing string 17 is lowered in. The lower end of the inner tube is connected to the inner tube connector 18. The lower connector 18.6 of the inner tube connector 18 is inserted into the support limit seat 20.9 of the double-layer tubing injection valve 20, and then secured to the docking slot 18.5 by the locking spring 20.3, thus achieving the installation connection between the inner tube and the double-layer tubing injection valve 20. Next, the pump barrel 3 is lowered into the casing 2 downhole via the sucker rod 6 connected to the pump plunger 4. The upper end of the sucker rod 6 is connected to the polished rod 8, and the polished rod 8 is connected to... The polished rod seal 9; the liquid outlet 7.2 of the large four-way valve 7 at the surface wellhead is connected to the inlet end of the gas-liquid separator 11 via the produced liquid pipeline 10. The gas outlet end of the gas-liquid separator 11 is connected to the gas booster pump 12 via a pipeline. The outlet of the gas booster pump 12 is connected to the pressure stabilizing tank 16 via the pressure reducing valve 13. The outlet of the pressure stabilizing tank 16 is connected to the air inlet 7.1 of the large four-way valve 7 via the circulating gas supply pipeline 15. The lower outlet of the pressure reducing valve 13 is connected to the pipeline at the outlet end of the gas-liquid separator 11 via a pipeline and a one-way valve 14 to release excess pressure to the inlet of the gas booster pump 12 for reuse. The liquid outlet end of the gas-liquid separator 11 is connected to the oil pipeline 21. 2. Start the pumping unit, gas booster pump 12, and gas-liquid separator 11. The sucker rod 8 and sucker rod 6 drive the pumping plunger 4 to move. During the downward movement of the pumping plunger 4, the sealing piston 20.4 of the double-layer tubing gas mixing valve 20 opens under the negative pressure inside the pumping barrel 3. Natural gas enters the pumping barrel 3 along the double-layer tubing 17, the second gas mixing channel 20.6 of the double-layer tubing gas mixing valve 20, and the gas inlet channel 20.8 of the gas mixing valve body. During the upward movement of the pumping plunger 4, the sealing piston 20.4 of the double-layer tubing gas mixing valve 20 closes under the increased pressure, and the second gas mixing... When channel 20.6 is closed, the heavy oil in the well is driven upward along the pump barrel 3 by the plunger 4 of the pump. During the upward movement, the natural gas mixed with the heavy oil is continuously mixed, which reduces the viscosity of the heavy oil. The viscosity-reduced oil is discharged to the outlet port 7.2 of the large four-way valve 7 at the wellhead, and then sent to the gas-liquid separator 11 for gas-liquid separation along the produced liquid pipeline 10. The separated natural gas is then sent to the pressure stabilizing tank 16 through the gas booster pump 12. If the separated natural gas is insufficient, sufficient natural gas is added to the gas booster pump 12 through the natural gas replenishment pipe 22. The separated liquid is sent to the oil pipeline 21. Third, as the plunger 4 of the oil pump moves down and up alternately, natural gas is continuously fed into the inner cavity of the oil pump barrel 3, where it mixes with heavy oil to reduce viscosity, thus realizing a cyclic heavy oil viscosity reduction extraction process.
[0029] The above description is merely a partial preferred embodiment of the present invention. Any person skilled in the art can modify the above-described technical solutions or modify them into equivalent technical solutions. Therefore, any simple modifications or equivalent transformations made based on the technical solutions of the present invention fall within the scope of protection claimed by the present invention.
Claims
1. A cold extraction device for heavy oil mixed with natural gas based on plunger pump, comprising a pump barrel (3), a pump plunger (4), a sucker rod (6), a four-way valve (7), a polished rod (8), and a polished rod sealer (9), characterized in that: It also includes a single-pipe gas-injection valve (5), a produced fluid pipeline (10), a gas-liquid separator (11), a gas booster pump (12), a pressure reducing valve (13), a check valve (14), a circulating gas supply pipeline (15), and a pressure stabilizing tank (16). The single-pipe gas-injection valve (5) is connected to the top of the pump barrel (3) through an oil pipe (1). The inlet of the single-pipe gas-injection valve (5) is connected to the circulating gas supply pipeline (15), and the circulating gas supply pipeline (15) is connected to the pressure stabilizing tank (16) on the surface wellhead along the annulus of the oil pipe (1) and the casing (2). The liquid outlet (7) of the large four-way valve (7) on the wellhead is connected to the gas outlet (7). 2) The gas-liquid separator (11) is connected to the inlet end of the gas-liquid separator (11) through the produced liquid pipeline (10). The gas outlet end of the gas-liquid separator (11) is connected to the gas booster pump (12) through the pipeline. The inlet end of the gas booster pump (12) is connected to the natural gas replenishment pipeline (22) in parallel. The outlet of the gas booster pump (12) is connected to the pressure stabilizing tank (16) through the pressure reducing valve (13). The lower outlet of the pressure reducing valve (13) is connected to the pipeline at the outlet end of the gas-liquid separator (11) through the pipeline and the check valve (14). The liquid outlet end of the gas-liquid separator (11) is connected to the oil pipeline (21).
2. The heavy oil-natural gas blending cold recovery device based on plunger pump oil production according to claim 1, characterized in that: The single-pipe gas mixing valve (5) includes an upper connector (5.1), a one-way valve plug (5.2), a valve body (5.3), a spring (5.4), a lower connector (5.5), a gas mixing channel (5.6), and an oil discharge channel (5.7). The upper end of the valve body (5.3) is connected to the upper connector (5.1), and the lower end is provided with a lower connector (5.5). A gas mixing channel (5.6) is provided on the side wall of the upper connector (5.1). A conical valve seat is provided at the lower end of the gas mixing channel (5.6). The one-way valve plug (5.2) is connected to the conical valve seat. A spring (5.4) is installed at the lower end of the one-way valve plug (5.2). An oil discharge channel (5.7) is provided at the center of the valve body (5.3).
3. A cold extraction device for heavy oil mixed with natural gas based on plunger pump, comprising a pump barrel (3), a pump plunger (4), a sucker rod (6), a large four-way valve (7), a polished rod (8), and a polished rod sealer (9), characterized in that: It also includes a double-layer tubing gas-injection valve (20), a double-layer tubing (17), an inner tube connector (18), a compensator (19), a produced fluid pipeline (10), a gas-liquid separator (11), a gas booster pump (12), a pressure reducing valve (13), a one-way valve (14), a circulating gas supply pipeline (15), and a pressure stabilizing tank (16). The double-layer tubing gas-injection valve (20) is installed at the upper end of the pump barrel (3). The upper end of the double-layer tubing gas-injection valve (20) is connected to the double-layer tubing (17) through the inner tube connector (18). The compensator (19) is installed at the middle and upper end of the double-layer tubing (17). The inlet of the double-layer tubing gas-injection valve (20) is connected to the circulating gas supply pipeline (15) on one side of the wellhead through the double-layer tubing (17). The gas is connected to the pressure tank (16) via the circulating gas supply pipeline (15). The liquid outlet (7.2) of the large four-way valve (7) on the wellhead is connected to the inlet end of the gas-liquid separator (11) via the produced liquid pipeline (10). The gas outlet end of the gas-liquid separator (11) is connected to the gas booster pump (12) via a pipeline. The inlet end of the gas booster pump (12) is connected to the natural gas replenishment pipeline (22) in parallel. The outlet of the gas booster pump (12) is connected to the pressure tank (16) via the pressure reducing valve (13). The lower outlet of the pressure reducing valve (13) is connected to the pipeline at the outlet end of the gas-liquid separator (11) via a pipeline and a one-way valve (14). The liquid outlet end of the gas-liquid separator (11) is connected to the oil pipeline (21).
4. The heavy oil-natural gas blending cold recovery device based on plunger pump oil production according to claim 3, characterized in that: The double-layer tubular gas mixing valve (20) includes a gas mixing valve conversion body (20.1), a sealing sleeve (20.2), a sealing piston (20.4), a second spring (20.5), a second gas mixing channel (20.6), a gas mixing valve body (20.7), and a gas mixing valve body inlet channel (20.8). The upper end of the gas mixing valve body (20.7) is connected to the gas mixing valve conversion body (20.1). The gas mixing valve body (20.7) has a gas mixing valve body inlet channel (20.8) in the middle. A gas mixing valve body outer wall is fitted with a gas mixing valve body inlet channel (20.8) in the middle. A sealing sleeve (20.2) is provided, the upper end of which is connected to the outer wall of the upper conversion body (20.1) of the gas mixing valve. A sealing piston (20.4) and a second spring (20.5) are installed in the cavity formed between the sealing sleeve (20.2) and the outer wall of the gas mixing valve body (20.7). An axial second gas mixing channel (20.6) is provided in the upper conversion body (20.1). The opening and closing of the second gas mixing channel (20.6) and the gas inlet channel (20.8) of the gas mixing valve body are controlled by the sealing piston (20.4).
5. The heavy oil-natural gas blending cold recovery device based on plunger pump oil production according to claim 4, characterized in that: The upper end of the gas mixing valve conversion body (20.1) is movably connected to the outer tube of the double-layer column (17). The upper part of the inner wall of the gas mixing valve conversion body (20.1) is provided with a locking spring (20.3), which is movably connected to the inner tube connector (18) through the locking spring (20.3) to realize the movable connection of the inner tube of the double-layer column (17).
6. The heavy oil-natural gas blending cold recovery device based on plunger pump oil production according to claim 5, characterized in that: The upper part of the inner wall of the gas mixing valve conversion body (20.1) is provided with a support limiting seat (20.9). The support limiting seat (20.9) is a conical structure and has multiple sealing grooves and a locking spring (20.3) distributed inside. The support limiting seat (20.9) is used to support the upper inner tube connector (18).
7. The heavy oil-natural gas blending cold recovery device based on plunger pump oil production according to claim 6, characterized in that: The outer diameter of the gas mixing valve body (20.7) is smaller than the outer diameter of the gas mixing valve upper conversion body (20.1). The gas mixing valve body (20.7), the gas mixing valve upper conversion body (20.1), and the support limit seat (20.9) are an integral structure. The outer walls of the gas mixing valve body (20.7) and the gas mixing valve upper conversion body (20.1) form a two-stage stepped structure. A sealing sleeve (20.2) is installed at the outer step. A sealing piston (20.4) and a second spring (20.5) are installed at the inner step and the cavity formed between the sealing sleeve (20.2) and the outer wall of the gas mixing valve body (20.7).
8. The heavy oil-natural gas blending cold recovery device based on plunger pump oil recovery according to claim 7, characterized in that: The inner tube connector (18) includes an upper connector (18.1), a safety shear pin (18.2), a connector body (18.3), a connector sealing ring (18.4), a connector groove (18.5), and a lower connector (18.6). The connector body (18.3) is a cylindrical structure, and a lower connector (18.6) is provided at the lower end of the connector body (18.3) for connecting with the support limit seat (20.9). The lower outer wall of the docking body (18.3) is provided with a docking groove (18.5) for movably connecting with the locking spring (20.3) of the double-layer tube column aeration valve (20). The upper end of the docking body (18.3) is connected to the upper connector (18.1) of the docking device through a safety shear pin (18.2) and a docking device sealing ring (18.4). The upper connector (18.1) of the docking device is provided with an internal thread for connecting with the internal tube thread of the double-layer tube column (17).
9. A method of using a heavy oil-natural gas blending cold recovery device based on a plunger pump, comprising the heavy oil-natural gas blending cold recovery device as described in claim 2, characterized in that... The process includes the following: First, the pump barrel (3) and the single-pipe gas-injecting valve (5) are lowered into the casing (2) downhole via the tubing (1). The inlet of the single-pipe gas-injecting valve (5) is connected to the circulating gas supply line (15). The circulating gas supply line (15) is connected to the outlet of the pressure tank (16) on the surface wellhead along the annulus of the tubing (1) and casing (2). Then, the pump plunger (4) is lowered into the pump barrel (3) via the sucker rod (6). The upper end of the sucker rod (6) is connected to the polished rod (8), and the polished rod seal (9) is connected to the polished rod (8). The liquid outlet of the large four-way valve (7) at the surface wellhead is connected to the pump barrel (3). The outlet (7.2) is connected to the inlet of the gas-liquid separator (11) via the produced liquid pipeline (10). The gas outlet of the gas-liquid separator (11) is connected to the gas booster pump (12) via a pipeline. The outlet of the gas booster pump (12) is connected to the pressure stabilizing tank (16) via a pressure reducing valve (13). The lower outlet of the pressure reducing valve (13) is connected to the pipeline at the outlet of the gas-liquid separator (11) via a pipeline and a check valve (14) to release excess pressure to the inlet of the gas booster pump (12) for reuse. The liquid outlet of the gas-liquid separator (11) is connected to the oil pipeline (21).
2. Start the pumping unit, gas booster pump (12), and gas-liquid separator (11). The pumping plunger (4) is moved by the polished rod (8) and sucker rod (6). During the downward movement of the pumping plunger (4), the one-way valve plug (5.2) of the single-tube gas mixing valve (5) opens under the action of reduced pressure, and natural gas enters the oil discharge channel (5.7) along the gas mixing channel (5.6) of the single-tube gas mixing valve (5). During the upward movement of the pumping plunger (4), the one-way valve plug (5.2) of the single-tube gas mixing valve (5) closes under the action of increased pressure, and the gas mixing channel (5.6) closes. At this time, the viscous liquid in the well... The oil is driven by the plunger (4) of the oil pump to move upward along the pump barrel (3). During the upward movement, the natural gas mixed with the heavy oil is continuously mixed, which reduces the viscosity of the heavy oil. The reduced viscosity oil is discharged to the outlet (7.2) of the large four-way valve (7) at the wellhead, and then sent to the gas-liquid separator (11) along the produced liquid pipeline (10) for gas-liquid separation. The separated natural gas is then sent to the pressure stabilizing tank (16) through the gas booster pump (12). If the separated natural gas is insufficient, sufficient natural gas is added to the gas booster pump (12) through the natural gas replenishment pipe (22), and the separated liquid is sent to the oil pipeline (21). Third, as the plunger (4) of the oil pump moves down and up alternately, natural gas is continuously fed into the inner cavity of the oil pump barrel (3), where it mixes with heavy oil in the inner cavity of the oil pump barrel (3) to reduce viscosity and achieve a circulating heavy oil viscosity reduction extraction process.
10. A method of using a heavy oil-natural gas blending cold recovery device based on a plunger pump, comprising the heavy oil-natural gas blending cold recovery device as described in claim 8, characterized in that... The process includes the following: First, the pump barrel (3) and the double-layer tubing gas-injecting valve (20) are lowered into the casing (2) downhole through the outer tube of the double-layer tubing string (17). The upper middle part of the outer tube is connected to the compensator (19). Then, the inner tube of the double-layer tubing string (17) is lowered in. The lower end of the inner tube is connected to the inner tube connector (18). The lower connector (18.6) of the inner tube connector (18) is inserted into the support limit seat (20.9) of the double-layer tubing gas-injecting valve (20). Then, the locking spring (20.3) is inserted into the docking slot (18.5) to realize the installation connection between the inner tube and the double-layer tubing gas-injecting valve (20). Then, the pump plunger (4) is connected to the sucker rod (6) and lowered into the pump barrel (3) in the casing (2) downhole. The upper end of the sucker rod (6) is connected to the polished rod (8). The polished rod (8) is connected to the upper part of the polished rod (8). Connect the polished rod seal (9); the liquid outlet (7.2) of the large four-way valve (7) at the surface wellhead is connected to the inlet end of the gas-liquid separator (11) through the produced liquid pipeline (10). The gas outlet end of the gas-liquid separator (11) is connected to the gas booster pump (12) through the pipeline. The outlet of the gas booster pump (12) is connected to the pressure stabilizing tank (16) through the pressure reducing valve (13). The outlet of the pressure stabilizing tank (16) is connected to the air inlet (7.1) of the large four-way valve (7) through the circulating gas supply pipeline (15). The lower outlet of the pressure reducing valve (13) is connected to the pipeline at the outlet end of the gas-liquid separator (11) through the pipeline and the one-way valve (14) to release excess pressure to the inlet of the gas booster pump (12) for reuse. The liquid outlet end of the gas-liquid separator (11) is connected to the oil pipeline (21).
2. Start the pumping unit, gas booster pump (12), and gas-liquid separator (11). The pumping unit plunger (4) is moved by the polished rod (8) and sucker rod (6). During the downward movement of the pumping unit plunger (4), the sealing piston (20.4) of the double-layer tubing gas mixing valve (20) opens under the negative pressure inside the pumping unit (3). Natural gas enters the pumping unit (3) along the double-layer tubing (17), the second gas mixing channel (20.6) of the double-layer tubing gas mixing valve (20), and the gas inlet channel (20.8) of the gas mixing valve body. During the upward movement of the pumping unit plunger (4), the sealing piston (20.4) of the double-layer tubing gas mixing valve (20) closes under the increased pressure. The second gas mixing channel (20.6) is closed. At this time, the heavy oil in the well is driven by the plunger (4) of the oil pump to go up along the oil pump barrel (3). During the upward process, the natural gas mixed with the heavy oil is continuously mixed, which reduces the viscosity of the heavy oil. The viscosity-reduced oil is discharged to the outlet (7.2) of the large four-way valve (7) at the wellhead, and then sent to the gas-liquid separator (11) along the produced liquid pipeline (10) for gas-liquid separation. The separated natural gas is then sent to the pressure stabilizing tank (16) through the gas booster pump (12). If the separated natural gas is insufficient, sufficient natural gas is added to the gas booster pump (12) through the natural gas replenishment pipe (22), and the separated liquid is sent to the oil pipeline (21). Third, as the plunger (4) of the oil pump moves down and up alternately, natural gas is continuously fed into the inner cavity of the oil pump barrel (3), where it mixes with heavy oil in the inner cavity of the oil pump barrel (3) to reduce viscosity and achieve a circulating heavy oil viscosity reduction extraction process.