A method and conveying device for oil extraction by alternating injection and self-regulating plugging

Abstract

This invention discloses an alternating injection self-regulating plugging method and conveying device for oil extraction, including a combustion furnace. A first connecting pipe is fixedly connected to one side of the top of the combustion furnace, and an air inlet pipe is fixedly connected to the bottom of the first connecting pipe. A water guide pipe is provided on the side of the air inlet pipe away from the combustion furnace. A sliding mechanism is provided between the air inlet pipe and the water guide pipe. This invention, through the provided sliding mechanism and the first scraping mechanism, can, when self-regulating plugging is required for oil extraction, alternately inject flue gas, after purification, cooling, and compression, with limewater sluice into the oil well for displacement oil extraction. This avoids the problems of existing profile control and sealing technologies, which mainly rely on injecting foam, gel, or solid particle plugging agents into the injection well to prevent gas channeling. These methods suffer from insufficient strength, short effective period, and inconsistencies between the plugging and channeling locations, resulting in low efficiency and high cost. This invention improves oil displacement efficiency.

Description

Technical Field

[0001] This invention relates to the field of oil extraction technology, specifically to an alternating injection self-regulating plugging method for oil extraction and a conveying device. Background Technology

[0002] Existing methods for developing heavy oil reservoirs mainly include steam injection, hot water huff and puff, thermochemical methods, chemical agent and polyacrylamide solution injection, water injection, carbon dioxide injection, nitrogen and carbon dioxide injection with chemical agents, steam injection with flue gas huff and puff, and burning of oil layers. Among them, the steam-assisted carbon dioxide and nitrogen injection method is a relatively new heavy oil extraction method. However, injecting high-purity carbon dioxide is not only costly but also detrimental to the carbon emission reduction development strategy, making the method unsustainable. With the increasing emphasis on carbon emission reduction, flue gas injection technology for oil extraction has been further developed. During the process of injecting flue gas into the oil layer through injection wells, the phenomenon of flue gas rushing rapidly along high-permeability layers and zones to the oil well has occurred, which is gas channeling. This reduces the effectiveness of gas injection for oil extraction and makes it difficult to effectively seal the flue gas underground. In some cases, the injection of flue gas may even be forced to terminate because the gas channeling prevents the injected flue gas from effectively acting on the oil reservoir. The other methods mentioned above are all constrained by the principles and characteristics of the process. Their technical effects and economic efficiency are limited by the stage adaptability. They are difficult to adapt to the continuous application under the condition of low residual oil in the middle and late stages of development. They are usually difficult to meet the development needs of further improving the recovery rate and low carbon economy. Especially when the oil field is developed to the middle and late stages with high water cut, scattered residual oil, depleted formation energy, and the stage of nearing negative benefits, it is difficult to extract the residual oil using existing methods and technologies. More inexpensive and effective technologies need to be invented. Oilfield heating furnaces and thermal recovery steam injection boilers produce large amounts of flue gas with high carbon dioxide and nitrogen content, which pollutes the environment when emitted into the air. Injecting the gas underground to drive oil recovery is a multi-benefit extraction method. With the country's emphasis on carbon emission reduction, flue gas injection technology for oil extraction has been further developed. However, during the process of injecting flue gas into the oil layer through injection wells, a phenomenon occurs where the flue gas rushes rapidly along the high-permeability zone to the production well, which is also known as gas channeling. This leads to ineffective gas injection and forced shutdown. Flue gas injection will become an important successor method for the subsequent development of heavy oil fields. The prominent problem of flue gas injection is that flue gas is more likely to flow into the oil wells in the direction of displacement, resulting in poor oil displacement effect. It is necessary to develop supporting and practical oil displacement and plugging technology. However, the existing profile control and plugging technology mainly prevents gas flow by injecting foam, gel, and solid particle plugging agents into the injection well. However, it has problems such as insufficient strength, short effective period, and the plugging location is different from the flow location, resulting in low efficiency and high cost. Summary of the Invention

[0003] The purpose of this invention is to provide an alternating injection self-regulating plugging method and conveying device for oil extraction, which can solve the problems mentioned in the background art.

[0004] To achieve the above objectives, the present invention provides the following technical solution: a method for alternating injection and self-regulating plugging extraction of oil, comprising the following steps: Step 1: Select the flue gas from the injection well or a combustion furnace near the oil field as the gas source; Step 2: The flue gas is collected, impurities are removed, it is cooled and dehydrated, and then compressed. The gas is then transported to the injection well through an alternating injection self-regulating plugging oil extraction method and a conveying device. Step 3: Stop injecting flue gas and observe the production dynamics of the oil well; Step 4: Based on the design and referring to the dynamics of surrounding oil wells, start the water pump and extract lime water of the designed concentration and injection volume from the inside of the water tank in a timely manner. Then, the lime water is injected into the gas injection well through the alternating injection self-regulating plugging oil extraction method and transportation device, so that it produces profile regulation and oil displacement effects underground. When the flue gas comes into contact with the lime water, the lime water reacts with the carbon dioxide in the flue gas to generate calcium carbonate precipitate and water. The precipitated and aggregated calcium carbonate regulates and plugs the gas channel seepage. Step 5: Observe the injection and production dynamics of the injection well and the production well; Step Six: Inject the second sluice block into the flue gas, and optimize and adjust the injection and production parameters based on the well group's production dynamics to maintain balanced displacement; Step 7: Inject lime water into the secondary slug, optimize the injection parameters and calcium hydroxide concentration, and observe the profile control effect; Step 8: Inject formation water produced in this oilfield to expand the oil displacement radius and range.

[0005] An alternating injection self-regulating plugging oil extraction conveying device includes a combustion furnace. A first connecting pipe is fixedly connected to one side of the top of the combustion furnace. An air inlet pipe is fixedly connected to the bottom end of the first connecting pipe. A water guide pipe is provided on the side of the air inlet pipe away from the combustion furnace. A sliding mechanism is provided between the air inlet pipe and the water guide pipe. A second connecting pipe is fixedly connected to the top of the water guide pipe. The end of the second connecting pipe away from the combustion furnace is embedded in the inner wall of a water tank. The water tank and the combustion furnace are at the same horizontal plane. Flue gas generated by oilfield steam heaters, thermal recovery steam injection boilers, etc., is purified, cooled, and compressed, and then alternately injected into the oil well with limewater sluice gate for displacement oil extraction, thereby improving oil displacement efficiency.

[0006] Preferably, the sliding mechanism includes a U-shaped tube disposed between the air inlet pipe and the water guide pipe. Magnets are provided on the inner walls of both ends of the U-shaped tube, and the two magnets are slidably connected to the U-shaped tube. Liquid water is contained inside the U-shaped tube and placed between the two magnets. A magnetic block is installed on one side of each of the two magnets. The two magnetic blocks are respectively disposed on the inner walls of the air inlet pipe and the water guide pipe and are slidably connected. A clearing mechanism is provided on the side of each magnetic block away from the magnets to prevent pipe blockage. This allows flue gas and lime water to be injected alternately for oil removal. The intermittent injection of lime water, as needed, controls flue gas leakage and achieves the best profile control and oil removal effect.

[0007] Preferably, the unblocking mechanism includes scraping plates fixedly connected to the two magnetic blocks on the side away from the magnet. The inner walls of both scraping plates have first holes, and multiple first holes are evenly distributed in a circumferential array. Each first hole has a first rotating mechanism at its top, and both scraping plates have a push-out mechanism at their bottom ends. A second rotating mechanism is installed at the bottom end of the scraping plate installed on the inner wall of the water guide pipe, allowing the flue gas and limewater to react spontaneously within the reservoir to generate calcium carbonate precipitate. This mechanism has the ability to automatically adjust and uniformly inject flue gas, and its effect is more pronounced in formations with significant interlayer differences and severe intralayer heterogeneity, thus compensating for the shortcomings of existing extraction processes and improving oilfield recovery.

[0008] Preferably, the first rotating mechanism includes a fixing ring disposed at the top of each first hole, the fixing ring being fixedly embedded in the inner wall of the first hole, a first fixing plate being disposed at the top of each fixing ring, each first fixing plate being installed at the top of the scraping plate, a first connecting rod being fixedly connected to one end of each first fixing plate, both ends of each first connecting rod being embedded in the inner wall of the first fixing block and being rotatably connected, and a torsion spring being installed on the inner wall of each first connecting rod to unclog the inner wall at the bottom of the pipe, thereby improving the unclogging effect of the pipe.

[0009] Preferably, the ejection mechanism includes a second fixing plate disposed at the bottom end of the two scraping plates. The inner walls of the two second fixing plates are provided with second holes. Multiple second holes are provided and are evenly distributed in a circumferential array. A support rod is fixedly connected to the top end of the second fixing plate installed in the inner wall of the air inlet pipe, and a support rod is fixedly connected to the bottom end of the second fixing plate installed in the inner wall of the water guide pipe. This facilitates the reaction between carbon dioxide and lime water to generate calcium carbonate precipitate, thereby adjusting and blocking the profile control and channeling of the large pores and high permeability zones of the oil layer, and effectively improving the heterogeneity of the bottom layer.

[0010] Preferably, the second rotating mechanism includes a connecting plate disposed at the bottom end of the scraping plate. The end of the connecting plate away from the scraping plate is embedded in the inner wall of the water guide pipe and is slidably connected. A second connecting rod is fixedly connected to the end of the connecting plate away from the scraping plate. A second spring is disposed at the top end of the second connecting rod. The second spring is disposed on the inner wall of one side of the water guide pipe and is fixedly connected to the top end of the water guide pipe. A toothed block is fixedly connected to the bottom end of one side of the second connecting rod. A gear meshes on one side of the toothed block. A third connecting rod is embedded in the inner wall of the gear. The third connecting rod is embedded in the inner wall of the second fixed plate and is fixedly connected. Both ends of the third connecting rod are embedded in the inner wall of the water guide pipe and are rotatably connected. The third rotating mechanism disposed on the inner wall of the third connecting rod prevents the sediment from falling onto the top end of the second fixed plate when the scraping plate scrapes off the sediment on the inner wall of the pipe, thereby reducing the sediment at the bottom end and nitrogen dioxide and improving the utilization rate of lime water.

[0011] Preferably, the third rotating mechanism includes a fourth connecting rod installed on the inner wall of the second fixed plate. Both ends of the fourth connecting rod are embedded in the inner wall of the third connecting rod and are fixedly connected. A first rotating block is fixedly sleeved on the outer wall of the fourth connecting rod. A second rotating block is installed on the top of the first rotating block. A fifth connecting rod is fixedly connected to the inner wall of the second rotating block. A first spring is sleeved on the outer wall of the bottom end of the fifth connecting rod. A sliding groove is formed on the inner wall of the top end of the fifth connecting rod. A slider is embedded in the inner wall of the sliding groove and is slidably connected. A scraping mechanism is installed on the outer wall of the slider. When the second fixed plate rotates, it drives the rotating plate to rotate and scrape off the sediment falling from the top of the second fixed plate, making it convenient to pour out the sediment.

[0012] Preferably, the scraping mechanism includes a second fixing block fixedly installed on the outer wall of the slider. The second fixing block is embedded in the inner wall of the second fixing plate and fixedly connected. A rotating plate is fixedly connected to the top of the second fixing block. The rotating plate is located at the top of the second fixing plate, which avoids the problem that the deposits adhere to the top of the second fixing plate, reducing the amount of substances that react with carbon dioxide and requiring repeated injection, resulting in a slow reaction process and affecting the oil displacement efficiency. This improves the oil displacement efficiency.

[0013] Preferably, the first rotating block is configured as an irregular arc-shaped protrusion, and the outer wall of the second rotating block is fixedly connected with several protrusions. The number of protrusions on the outer wall of the second rotating block is the same as the number of rotating plates, which drives the rotating plates to scrape the top of the second fixed plate, thereby improving the utilization rate of lime water.

[0014] Compared with the prior art, the beneficial effects of the present invention are: 1. This invention discloses an alternating injection self-regulating plugging method for oil extraction, in which flue gas generated by oilfield steam heaters, thermal recovery steam injection boilers, etc., is purified, cooled and compressed, and then alternately injected into oil wells with limewater sluice plugs to drive oil production and improve oil displacement efficiency.

[0015] 2. This invention, through the sliding mechanism and the first scraping mechanism, can use air or water pressure as power to drive the scraping plate to slide within the pipe wall when it is necessary to unclog the inner wall of the pipe. This avoids the problem that gas, being lighter, can easily drift from the bottom of the air inlet pipe into the bottom of the water pipe, causing carbon dioxide and lime water to react and produce precipitation, thus blocking the pipe opening and affecting pipeline transportation. This also prevents carbon dioxide and lime water from reacting in the original position, thus failing to achieve the oil displacement effect. This allows underground crude oil to be more effectively displaced to the oil well and extracted, ensuring the stability of the device operation.

[0016] 3. This invention, through its sliding mechanism, allows for simultaneous reverse movement of two scraping plates when air or water pressure is required. This movement causes the scraping plates to move, which in turn causes the magnet to squeeze the liquid water inside the U-shaped tube, causing the scraping plate on the other side to move simultaneously. This allows the two scraping plates to move in opposite directions within the inner walls of the air inlet pipe and water guide pipe, achieving alternating, back-and-forth movement. This clears the inner walls of the pipes, preventing blockages, and allows for the alternating injection of flue gas and lime water to drive the oil. The intermittent injection of lime water, as needed, controls flue gas leakage, achieving the best profile control and oil displacement effect.

[0017] 4. This invention, through its first unblocking mechanism, allows for the movement of a scraper within the inner wall of the water pipe when unblocking is required. The outer wall of the scraper scrapes against the inner wall of the water pipe, preventing the lighter gas from drifting from the bottom of the inlet pipe into the bottom of the water pipe during flue gas injection. This avoids the problem of carbon dioxide reacting with lime water remaining on the inner wall of the water pipe, producing precipitation that blocks the pipe opening and affects subsequent reactions. Instead, the flue gas and lime water react spontaneously within the reservoir to form calcium carbonate precipitate. This invention has the ability to automatically adjust and uniformly inject flue gas, and its effect is more pronounced in formations with significant interlayer differences and severe intralayer heterogeneity, thus compensating for the shortcomings of existing extraction processes and improving oilfield recovery rates. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a schematic cross-sectional view of the overall structure of the present invention; Figure 3 This is a schematic cross-sectional view of a partial structure of the present invention; Figure 4 For the present invention Figure 2 Enlarged view of point A in the middle; Figure 5 For the present invention Figure 3 Enlarged view at point B in the middle; Figure 6 For the present invention Figure 3 Enlarged view at point C; Figure 7 For the present invention Figure 3 Enlarged view at point D; Figure 8 For the present invention Figure 3 Enlarged view of point E in the middle.

[0019] In the diagram: 1. Combustion furnace; 2. First connecting pipe; 3. Air inlet pipe; 4. Water tank; 5. Second connecting pipe; 6. Water guide pipe; 7. U-shaped pipe; 8. Magnet; 9. Magnetic block; 10. Scraper; 11. First hole; 12. Fixing ring; 13. First fixing block; 14. First connecting rod; 15. First fixing plate; 16. Torsion spring; 17. Second connecting rod; 18. Tooth block; 19. Gear; 20. Third connecting rod; 21. Second fixing plate; 22. Second hole; 23. Fourth connecting rod; 24. First rotating block; 25. Second rotating block; 26. First spring; 27. Fifth connecting rod; 28. Slide groove; 29. ​​Sliding block; 30. Second fixing block; 31. Rotating plate; 32. Support rod; 33. Connecting plate; 34. Second spring. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Example 1

[0021] Please see Figure 1-3 The diagram illustrates an alternating injection self-regulating plugging method for oil extraction, comprising the following steps: Step 1: Select the flue gas from the wellbore or the combustion furnace 1 near the oil field as the gas source; Step 2: The flue gas is collected, impurities are removed, it is cooled and dehydrated, and then compressed. The gas is then transported to the injection well through an alternating injection self-regulating plugging oil extraction method and a conveying device. Step 3: Stop injecting flue gas and observe the production dynamics of the oil well; Step 4: Based on the design and referring to the dynamics of surrounding oil wells, start the water pump and extract lime water of the designed concentration and injection volume from the inside of water tank 4 in a timely manner. Then, the lime water is injected into the steam injection well through the alternating injection self-adjusting plugging oil extraction method and transportation device, so that it produces profile adjustment and oil displacement effect underground. When the flue gas comes into contact with the lime water, the lime water reacts with the carbon dioxide in the flue gas to generate calcium carbonate precipitate and water. The precipitated and aggregated calcium carbonate adjusts and plugs the gas channel seepage. Step 5: Observe the injection and production dynamics of the injection well and the production well; Step Six: Inject the second sluice block into the flue gas, and optimize and adjust the injection and production parameters based on the well group's production dynamics to maintain balanced displacement; Step 7: Inject lime water into the secondary slug, optimize the injection parameters and calcium hydroxide concentration, and observe the profile control effect; Step 8: Inject formation water produced in this oilfield to expand the oil displacement radius and range.

[0022] Please see Figure 6 The diagram illustrates a conveying device for alternating injection and self-regulating oil extraction, comprising a combustion furnace 1. A first connecting pipe 2 is fixedly connected to one side of the top of the combustion furnace 1, and an air inlet pipe 3 is fixedly connected to the bottom end of the first connecting pipe 2. A water guide pipe 6 is provided on the side of the air inlet pipe 3 away from the combustion furnace 1. A sliding mechanism is provided between the air inlet pipe 3 and the water guide pipe 6. A second connecting pipe 5 is fixedly connected to the top end of the water guide pipe 6, and the end of the second connecting pipe 5 away from the combustion furnace 1 is embedded in the inner wall of a water tank 4. The water tank 4 and the combustion furnace 1 are at the same horizontal plane. This invention utilizes the sliding mechanism and the first scraper... When it is necessary to unclog the inner wall of the pipeline, the mechanism can use air or water pressure as power to drive the scraper 10 to slide within the pipeline wall, thus clearing the inner wall. This avoids the problem that gas, being lighter, can easily drift from the bottom of the air inlet pipe 3 into the bottom of the water guide pipe 6, causing carbon dioxide and lime water to react and produce sediment, thereby blocking the pipeline opening, affecting pipeline transportation, and preventing carbon dioxide and lime water from reacting in the original position, thus failing to achieve the oil displacement effect. This allows underground crude oil to be more effectively displaced to the oil well and extracted, ensuring the stability of the unit's operation.

[0023] The sliding mechanism includes a U-shaped tube 7 disposed between the air inlet pipe 3 and the water guide pipe 6. Magnets 8 are installed on the inner walls of both ends of the U-shaped tube 7, and the two magnets 8 are slidably connected to the U-shaped tube 7. Liquid water is contained inside the U-shaped tube 7 and is positioned between the two magnets 8. A magnetic block 9 is installed on one side of each of the two magnets 8. The two magnetic blocks 9 are respectively disposed on the inner walls of the air inlet pipe 3 and the water guide pipe 6 and are slidably connected. A clearing mechanism is provided on the side of each magnetic block 9 away from the magnets 8. Through the sliding mechanism, when it is necessary to move the two scraper plates 1... When the scraper plates 10 and 8 move in opposite directions simultaneously, the scraper plates 10 can be moved by air or water pressure, which in turn causes the magnet 8 to squeeze the liquid water inside the U-shaped tube 7, causing the scraper plates 10 on the other side to move simultaneously. This allows the two scraper plates 10 to move in opposite directions within the inner walls of the air inlet pipe 3 and the water guide pipe 6, achieving alternating and back-and-forth movement. This clears the inner walls of the pipes, prevents blockage, and allows flue gas and lime water to be injected alternately to drive the oil. The lime water is injected intermittently as needed to control flue gas leakage and achieve the best effect of profile control and oil removal.

[0024] The unblocking mechanism includes scraper plates 10 fixedly connected to the two magnetic blocks 9 on the side away from the magnet 8. The inner walls of both scraper plates 10 have multiple first holes 11 arranged in a circumferential array. Each first hole 11 has a first rotating mechanism at its top, and both scraper plates 10 have an ejection mechanism at their bottom. A second rotating mechanism is located at the bottom of the scraper plate 10 installed on the inner wall of the water pipe 6. Through the first unblocking mechanism, when unblocking is needed on the inner wall of the water pipe 6, the scraper plates 10 can move within the inner wall of the water pipe 6, allowing unblocking to proceed. The outer wall of the scraper 10 scrapes the inner wall of the water guide pipe 6, preventing the gas from being too light and easily drifting from the bottom of the intake pipe 3 into the bottom of the water guide pipe 6 during flue gas injection. This would cause carbon dioxide to react with the lime water remaining on the inner wall of the water guide pipe 6, producing precipitation that would block the pipe opening and affect subsequent reactions. Instead, the flue gas and lime water react spontaneously within the reservoir to form calcium carbonate precipitate. This method has the ability to automatically adjust and uniformly inject flue gas, and its effect is more pronounced in formations with large inter-layer differences and severe intra-layer heterogeneity, thus compensating for the shortcomings of existing extraction technologies and improving oilfield recovery. Example 2

[0025] Please see Figure 4 and Figure 5This embodiment further explains Example 1. The first rotating mechanism includes a fixing ring 12 disposed at the top of each first hole 11. The fixing ring 12 is fixedly embedded in the inner wall of the first hole 11. Each fixing ring 12 has a first fixing plate 15 disposed at its top. Each first fixing plate 15 is installed at the top of the scraping plate 10. One end of each first fixing plate 15 is fixedly connected to a first connecting rod 14. Both ends of each first connecting rod 14 are embedded in the inner wall of the first fixing block 13 and are rotatably connected. Each inner wall of the first connecting rod 14 is equipped with a torsion spring 16. Through the first rotating mechanism, when it is necessary to move the scraping plate 10 by air pressure or water pressure, the first hole 11 can be blocked by the first fixing plate 15. This facilitates the movement of the scraping plate 10 by air pressure or water pressure, preventing the first hole 11 from opening and causing the water pressure or air pressure to decrease, thus preventing the scraping plate 10 from reaching the bottom of the pipe and clearing the inner wall of the bottom of the pipe, thereby improving the pipe clearing effect.

[0026] The ejection mechanism includes a second fixing plate 21 located at the bottom of two scraping plates 10. The inner walls of both second fixing plates 21 are provided with second holes 22. Multiple second holes 22 are evenly distributed in a circumferential array. A support rod 32 is fixedly connected to the top of the second fixing plate 21 installed in the inner wall of the air inlet pipe 3, and a support rod 32 is fixedly connected to the bottom of the second fixing plate 21 installed in the inner wall of the water guide pipe 6. Through this ejection mechanism, when gas or water needs to flow out of the pipe, the scraping plates 10 can move downwards, and the support rod 32 is embedded in the inner wall of the first hole 11, causing the first fixing plate 15 to rotate around the first connecting rod 14, opening the first hole 11 and allowing gas or water to flow downwards from the inner wall of the first hole 11. This facilitates the reaction of carbon dioxide with lime water to generate calcium carbonate precipitate, adjusting and blocking the profile control and channeling of the large pores and high-permeability zones of the oil layer, effectively improving the heterogeneity of the bottom layer. Example 3

[0027] Please see Figure 6-8This embodiment further illustrates other embodiments. The second rotating mechanism shown in the figure includes a connecting plate 33 disposed at the bottom end of the scraping plate 10. One end of the connecting plate 33 away from the scraping plate 10 is embedded in the inner wall of the water guide pipe 6 and is slidably connected. A second connecting rod 17 is fixedly connected to the end of the connecting plate 33 away from the scraping plate 10. A second spring 34 is disposed at the top end of the second connecting rod 17. The second spring 34 is disposed on the inner wall of one side of the water guide pipe 6, and its top end is fixedly connected to the water guide pipe 6. A toothed block 18 is fixedly connected to the bottom end of one side of the second connecting rod 17. A gear 19 meshes with one side of the toothed block 18. A third connecting rod 20 is embedded in the inner wall of the gear 19. The third connecting rod 20 is embedded in the second fixed plate. The inner wall of the second fixed plate 21 is fixedly connected, and the two ends of the third connecting rod 20 are embedded in the inner wall of the water guide pipe 6 and are rotatably connected. The inner wall of the third connecting rod 20 is provided with a third rotating mechanism. Through the set second rotating mechanism, when it is necessary to pour out the sediment at the top of the second fixed plate 21, the movement of the scraping plate 10 can drive the movement of the connecting plate 33, and the tooth block 18 drives the rotation of the gear 19, thereby flipping the second fixed plate 21 and scraping off the sediment that fell on the top of the second fixed plate 21 by the scraping plate 10. This avoids the sediment falling on the top of the second fixed plate 21 when the scraping plate 10 scrapes off the sediment on the inner wall of the pipe, so as to reduce the sediment generated at the bottom and nitrogen dioxide and improve the utilization rate of lime water.

[0028] The third rotating mechanism includes a fourth connecting rod 23 installed on the inner wall of the second fixed plate 21. Both ends of the fourth connecting rod 23 are embedded in the inner wall of the third connecting rod 20 and are fixedly connected. A first rotating block 24 is fixedly sleeved on the outer wall of the fourth connecting rod 23. A second rotating block 25 is installed on the top of the first rotating block 24. A fifth connecting rod 27 is fixedly connected to the inner wall of the second rotating block 25. A first spring 26 is sleeved on the outer wall of the bottom end of the fifth connecting rod 27. A groove 28 is formed on the inner wall of the top end of the fifth connecting rod 27. The inner wall of the groove 28 is embedded in... There is a slider 29, which is slidably connected. The outer wall of the slider 29 is equipped with a scraping mechanism. Through the set third rotation mechanism, when it is necessary to scrape the top of the second fixed plate 21 by rotating the rotating plate 31, the first rotating block 24 can be rotated by rotating the fourth connecting rod 23. The fifth connecting rod 27 slides in the inner wall of the second fixed block 30, causing the rotating plate 31 to rotate. When the second fixed plate 21 rotates, it drives the rotating plate 31 to rotate and scrape off the sediment falling from the top of the second fixed plate 21, making it convenient to pour out the sediment.

[0029] The scraping mechanism includes a second fixing block 30 fixedly installed on the outer wall of the slider 29. The second fixing block 30 is embedded in the inner wall of the second fixing plate 21 and fixedly connected. A rotating plate 31 is fixedly connected to the top of the second fixing block 30. The rotating plate 31 is located at the top of the second fixing plate 21. With the scraping mechanism, when it is necessary to scrape off the deposits at the top of the second fixing plate 21, the rotation of the second fixing block 30 can drive the rotating plate 31 to scrape off the deposits at the top of the second fixing plate 21. This makes it easier for the deposits to fall downwards when the second fixing plate 21 rotates, avoiding the problem that the deposits adhere to the top of the second fixing plate 21, which reduces the amount of substances that react with carbon dioxide, requires repeated injection, slows down the reaction process, and affects the oil displacement efficiency. This improves the oil displacement efficiency.

[0030] The first rotating block 24 is configured as an irregular arc-shaped protrusion, and the outer wall of the second rotating block 25 is fixedly connected with several protrusions. The number of protrusions on the outer wall of the second rotating block 25 is the same as the number of rotating plates 31. By configuring the first rotating block 24 as an irregular arc-shaped protrusion, when the second rotating block 25 needs to move, it can contact the second rotating block 25 through the highest point of the first rotating block 24, driving the second rotating block 25 to move upward. When the highest point of the first rotating block 24 does not contact the second rotating block 25, it drives the second rotating block 25 to move downward, causing the fifth connecting rod 27 to slide up and down and rotate in the inner wall of the second fixed block 30, driving the rotating plate 31 to scrape the top of the second fixed plate 21, thereby improving the utilization rate of lime water.

[0031] Working principle: When heavy oil needs to be extracted, the air intake pipe 3 and the water pipe 6 are first pre-buried in the land to be extracted. The flue gas from the injection well or the combustion furnace 1 near the oil field is selected as the gas source. The flue gas produced by the commonly used steam boiler in the oil field contains more than 75% nitrogen and 12%-15% carbon dioxide. The flue gas is collected, impurities are removed, it is cooled and dehydrated, and then compressed before being transported to the injection well via a conveying device. As the gas moves downward through the intake pipe 3, the gas pressure drives the scraper 10 to move downward in the inner wall of the intake pipe 3. When the scraper 10 moves to the top of the second fixed plate 21, the scraper 10 continues to move downward, causing the support rod 32 to pass through the first hole 11 and push the first fixed plate 15 to rotate around the first connecting rod 14, so that the gas flows downward and reaches the appropriate position. Stop injecting flue gas and observe the production dynamics of the oil well. After flue gas is injected into the reservoir, it can effectively reduce the viscosity of crude oil, improve the oil-water viscosity ratio, extract and vaporize the light hydrocarbons in the reservoir, generate dissolved gas drive, reduce interfacial tension, replenish formation energy and improve permeability. At the same time, carbon dioxide has a certain solubility in water and is easy to enter but not easy to leave in the closed reservoir. It can effectively bury a certain amount of carbon dioxide gas and alleviate the pressure of carbon emission reduction on the surface. Based on the design and referring to the dynamics of surrounding oil wells, the water pump is started to extract lime water of the designed concentration and injection volume from the inside of water tank 4 in a timely manner. Then, the lime water is injected into the steam injection well through the conveying device. The water pressure of the lime water flowing downwards along the inner wall of the water pipe 6 causes the scraper 10 to move downwards. When the scraper 10 reaches the top of the connecting plate 33, it continues to move downwards, causing the connecting plate 33 to move. The movement of the connecting plate 33 causes the second connecting rod 17 to move, which in turn causes the toothed block 18 to move. The movement of the toothed block 18 causes the gear 19 to rotate, which in turn causes the third connecting rod 20 to rotate. The rotation of the third connecting rod 20 causes the fourth connecting rod 23 to rotate, which in turn causes the first rotating block 24 to rotate. The rotation of the first rotating block 24 causes the second rotating block 25 to move upwards, which in turn causes the fifth connecting rod 27 to move upwards within the inner wall of the second fixed block 30. The upward movement of the fifth connecting rod 27 causes the slider 29 to move in the groove 2. Sliding within the inner wall of 8, since the first rotating block 24 is set as an irregular protrusion, when the highest point of the first rotating block 24 is not in contact with the second rotating block 25, it drives the second rotating block 25 to move downward and rotate. The rotation of the second rotating block 25 drives the second fixed block 30 to rotate, and the rotation of the second fixed block 30 drives the rotating plate 31 to rotate, causing the rotating plate 31 to rotate at the top of the second fixed plate 21, scraping the top of the second fixed plate 21. At the same time, the rotation of the third connecting rod 20 drives the rotation of the second fixed plate 21. The second fixed plate 21 flips, causing the sediment at the top of the second fixed plate 21 to fall downward. The flip of the second fixed plate 21 causes the support rod 32 to contact the first fixed plate 15, rotating the first fixed plate 15, so that the lime water flows downward from the inner wall of the first hole 11, continues downward through the second hole 22, to the appropriate position. When carbon dioxide in the flue gas mixes with subsequently injected limewater (i.e., calcium hydroxide solution), it produces calcium carbonate precipitate, which acts as a profile control and sealing agent. Research and evaluation experiments show that when the calcium hydroxide concentration in the limewater reaches or exceeds 0.01 mg / L, under normal reservoir conditions, it can rapidly produce calcium carbonate precipitate upon encountering carbon dioxide in the flue gas. More calcium carbonate precipitate forms in areas with higher flue gas flow, creating a sealing effect on heterogeneous, highly permeable layers and areas. The amount of calcium carbonate deposited automatically controls the flow channels, preventing gas channeling, improving flue gas drive, and increasing oil recovery. Therefore, it possesses an automatic selective distribution function, automatically diverting flue gas to drive crude oil from other areas to the production well. It is economical, efficient, and achieves a self-regulating effect with half the effort, ensuring relatively uniform and sustainable displacement production. The chemical reaction equation is: Ca(OH) + CO2 → CaCO3 + H2O Observe the injection and production dynamics of injection wells and production wells; The movement of lime water causes the scraper 10 to move, the movement of the scraper 10 causes the magnetic block 9 to move, and the movement of the magnetic block 9 causes the magnet 8 to move. Since liquid water is pre-installed in the inner wall of the U-shaped tube 7, the magnet 8 on the side closer to the water guide pipe 6 moves downward, causing the magnet 8 on the side farther away from the water guide pipe 6 to move, thereby causing the scraper 10 in the inner wall of the air inlet pipe 3 to move upward, so that when the flue gas is injected next time, the air pressure of the flue gas flow will cause the scraper 10 to move downward. The second sluice gate is injected with flue gas. The injection and production parameters are optimized and adjusted according to the production dynamics of the well group to maintain balanced displacement. Inject lime water into a secondary slug, optimize injection parameters, and observe the profile control effect; Injecting formation water produced in this oilfield will expand the radius and extent of oil displacement. Depending on the specific development situation and needs, flue gas, lime water, and produced water can be injected alternately multiple times. The injection parameters of each sluice block are set according to the best oil displacement effect. The cyclic injection of multiple sluice blocks can achieve the purpose of increasing production and improving the recovery rate. For new wells and heavy oil reservoirs with low recovery rates and high remaining oil, the method of sequentially injecting three sluices—flue gas, lime water, and formation water—into a single well, then shutting down the well before opening it for oil production can be adopted. This is also known as the multi-round flue gas and lime water injection and production process. Flue gas has the functions of oil displacement, viscosity reduction, formation energy increase, and oil displacement efficiency improvement. Since lime water is alkaline, oils hydrolyze under alkaline conditions to produce higher fatty acid salts and glycerol. Glycerol is soluble in water, so lime water has a certain oil washing effect. Lime water reacts with carbon dioxide in flue gas to form calcium carbonate precipitate, which adjusts and blocks the large pores and high permeability zones of the oil layer, effectively improving the heterogeneity of the bottom layer. The alternating injection of gas and water also enhances oil displacement and prevents flue gas crossflow for oil layers with different pore structures and sizes. Carbon dioxide can dissolve in underground oil and water fluids and can also be found in some oil-bearing pores in underground rocks. It can displace some crude oil, further improve oil recovery, and store some carbon dioxide gas; thus achieving the dual goals of oil displacement and emission reduction. Nitrogen in flue gas can replenish formation energy, displace residual oil that cannot be displaced by fine pore water, and assist in the extraction process. Relying on the synergistic effect of carbon dioxide and nitrogen with calcium hydroxide and water, underground crude oil can be more effectively displaced to the production well and extracted.

[0032] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus.

[0033] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for extracting oil using alternating injection and self-regulating plugging, characterized in that: Includes the following steps: Step 1: Select the flue gas from the combustion furnace (1) near the injection well or oil field as the gas source; Step 2: After collecting, removing impurities, cooling and dehydrating, and compressing the flue gas, the gas is transported to the injection well through an alternating injection self-regulating plugging oil extraction method and a transportation device. Step 3: Stop injecting flue gas and observe the production dynamics of the oil well; Step 4: Based on the design and referring to the dynamics of the surrounding oil wells, start the water pump and extract the lime water of the designed concentration and injection volume from the inside of the water tank (4) in a timely manner. Then, the lime water is injected into the steam injection well through the alternating injection self-adjusting plugging oil extraction method and transportation device, so that it can produce profile adjustment and oil displacement effect underground. When the flue gas comes into contact with the lime water, the lime water reacts with the carbon dioxide in the flue gas to generate calcium carbonate precipitate and water. The precipitated and aggregated calcium carbonate adjusts and plugs the gas channel seepage. Step 5: Observe the injection and production dynamics of the injection well and the production well; Step Six: Inject the second sluice block into the flue gas, and optimize and adjust the injection and production parameters based on the well group's production dynamics to maintain balanced displacement; Step 7: Inject lime water into the secondary slug, optimize the injection parameters and calcium hydroxide concentration, and observe the profile control effect; Step 8: Inject formation water produced in this oilfield to expand the oil displacement radius and range.

2. A conveying device for alternating injection and self-regulating oil extraction, comprising a combustion furnace (1), characterized in that: A first connecting pipe (2) is fixedly connected to one side of the top of the combustion furnace (1). An air inlet pipe (3) is fixedly connected to the bottom of the first connecting pipe (2). A water guide pipe (6) is provided on the side of the air inlet pipe (3) away from the combustion furnace (1). A sliding mechanism is provided between the air inlet pipe (3) and the water guide pipe (6). A second connecting pipe (5) is fixedly connected to the top of the water guide pipe (6). The end of the second connecting pipe (5) away from the combustion furnace (1) is provided on the inner wall of the water tank (4). The water tank (4) and the combustion furnace (1) are on the same horizontal plane.

3. The conveying device for alternating injection and self-regulating oil extraction according to claim 2, characterized in that: The sliding mechanism includes a U-shaped tube (7) disposed between the air inlet pipe (3) and the water guide pipe (6). The inner walls of both ends of the U-shaped tube (7) are provided with magnets (8). The two magnets (8) are slidably connected to the U-shaped tube (7). The U-shaped tube (7) is filled with liquid water, which is placed between the two magnets (8). A magnetic block (9) is installed on one side of each of the two magnets (8). The two magnetic blocks (9) are respectively disposed on the inner walls of the air inlet pipe (3) and the water guide pipe (6) and are slidably connected. A dredging mechanism is provided on the side of each magnetic block (9) away from the magnet (8).

4. The conveying device for alternating injection and self-regulating oil extraction according to claim 3, characterized in that: The unblocking mechanism includes scraping plates (10) fixedly connected to the two magnetic blocks (9) on the side away from the magnet (8). The inner walls of the two scraping plates (10) are provided with first holes (11) and are evenly distributed in a circumferential array. The top of each first hole (11) is provided with a first rotating mechanism, and the bottom of the two scraping plates (10) is provided with an ejection mechanism. The bottom of the scraping plate (10) installed on the inner wall of the water pipe (6) is provided with a second rotating mechanism.

5. The conveying device for alternating injection and self-regulating plugging oil extraction according to claim 4, characterized in that: The first rotating mechanism includes a fixing ring (12) disposed at the top of each first hole (11). The fixing ring (12) is fixedly embedded in the inner wall of the first hole (11). Each fixing ring (12) is provided with a first fixing plate (15) at its top. Each first fixing plate (15) is installed at the top of the scraping plate (10). One end of each first fixing plate (15) is fixedly connected to a first connecting rod (14). Both ends of each first connecting rod (14) are embedded in the inner wall of the first fixing block (13) and are rotatably connected. A torsion spring (16) is installed on the inner wall of each first connecting rod (14).

6. The conveying device for alternating injection and self-regulating plugging oil extraction according to claim 4, characterized in that: The ejection mechanism includes a second fixing plate (21) disposed at the bottom of the two scraping plates (10). The inner walls of the two second fixing plates (21) are provided with second holes (22) and are evenly distributed in a circumferential array. A support rod (32) is fixedly connected to the top of the second fixing plate (21) installed in the inner wall of the air inlet pipe (3). A support rod (32) is fixedly connected to the bottom of the second fixing plate (21) installed in the inner wall of the water guide pipe (6).

7. The conveying device for alternating injection and self-regulating oil extraction according to claim 4, characterized in that: The second rotating mechanism includes a connecting plate (33) disposed at the bottom end of the scraper (10). One end of the connecting plate (33) away from the scraper (10) is embedded in the inner wall of the water guide pipe (6) and is slidably connected. A second connecting rod (17) is fixedly connected to the other end of the connecting plate (33) away from the scraper (10). A second spring (34) is disposed at the top end of the second connecting rod (17). The second spring (34) is disposed on the inner wall of one side of the water guide pipe (6). The top end of the second spring (34) is connected to the water guide pipe (6). The water pipe (6) is fixedly connected, and a toothed block (18) is fixedly connected to the bottom end of one side of the second connecting rod (17). A gear (19) meshes with one side of the toothed block (18). A third connecting rod (20) is embedded in the inner wall of the gear (19). The third connecting rod (20) is embedded in the inner wall of the second fixed plate (21) and is fixedly connected. The two ends of the third connecting rod (20) are embedded in the inner wall of the water pipe (6) and are rotatably connected. A third rotating mechanism is provided on the inner wall of the third connecting rod (20).

8. The conveying device for alternating injection and self-regulating oil extraction according to claim 7, characterized in that: The third rotating mechanism includes a fourth connecting rod (23) installed on the inner wall of the second fixed plate (21). Both ends of the fourth connecting rod (23) are embedded in the inner wall of the third connecting rod (20) and are fixedly connected. A first rotating block (24) is fixedly sleeved on the outer wall of the fourth connecting rod (23). A second rotating block (25) is installed on the top of the first rotating block (24). A fifth connecting rod (27) is fixedly connected to the inner wall of the second rotating block (25). A first spring (26) is sleeved on the outer wall of the bottom end of the fifth connecting rod (27). A sliding groove (28) is opened on the inner wall of the top end of the fifth connecting rod (27). A slider (29) is embedded in the inner wall of the sliding groove (28) and is slidably connected. A scraping mechanism is installed on the outer wall of the slider (29).

9. A conveying device for alternating injection and self-regulating oil extraction according to claim 8, characterized in that: The scraping mechanism includes a second fixing block (30) fixedly installed on the outer wall of the slider (29). The second fixing block (30) is embedded in the inner wall of the second fixing plate (21) and fixedly connected. A rotating plate (31) is fixedly connected to the top of the second fixing block (30). The rotating plate (31) is located at the top of the second fixing plate (21).

10. A conveying device for alternating injection and self-regulating oil extraction according to claim 8, characterized in that: The first rotating block (24) is set as an irregular arc-shaped protrusion, and the outer wall of the second rotating block (25) is uniformly fixedly connected with protrusions. The number of protrusions on the outer wall of the second rotating block (25) is the same as the number of rotating plates (31).

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