Hydraulic lifting process for immovable string steam injection oil and gas production

Abstract

The invention discloses an immovable string steam injection oil and gas production hydraulic lifting process, and relates to the technical field of mechanical oil and gas production equipment. According to the immovable tubular column steam injection oil and gas production hydraulic lifting technology, the working process of the immovable tubular column steam injection oil and gas production hydraulic lifting technology comprises the following steps that S1, in the ground working stage, ground equipment is composed and acts; and S2, the underground working stage is divided into an oil pumping process and a steam injection process, and the oil pumping process can also be divided into an upstroke stage and a downstroke stage. The frequency converter is adopted to adjust the frequency, a double-channel structure is adopted, resetting of the hydraulic lifting device is completed, the reciprocating mode achieves pumping of crude oil, due to the fact that a sucker rod is not arranged, the sucker rod is not stretched and shortened, and meanwhile when a pipe column is stretched and shortened, the feedback oil well pump is stretched and shortened as well, the effective stroke of the feedback oil well pump is prolonged, and the oil pumping efficiency is improved. The effective discharge capacity of the pump is improved, the tripping-in depth of the oil well pump can be effectively increased, and then the production potential of an oil well can be fully exerted.

Description

Technical Field

[0001] The invention relates to the technical field of mechanical oil and gas production equipment, and in particular to a hydraulic lifting process for oil and gas production by injecting steam into a fixed pipe column. Background Art

[0002] Heavy oil development refers to the process of exploiting crude oil with higher viscosity (i.e., heavy oil) in underground reservoirs. Heavy oil is a special type of oil resource, and its viscosity is significantly higher than that of conventional crude oil. Generally speaking, at reservoir temperature, when the viscosity of crude oil exceeds 100mPa・s or the API gravity (an indicator of crude oil density) is less than 20°, it is usually classified as heavy oil.

[0003] At present, domestic heavy oil development mainly adopts steam huff and puff, more than 90% of oil wells use beam rod pumping system, and more than 50% of oil wells use fixed pipe string pumping technology. However, due to the problem of eccentric wear of rods and pipes in directional wells, cluster wells and horizontal wells, the depth of pumping is limited, and the production potential of oil wells cannot be fully utilized. Due to structural reasons, there are the following shortcomings: 1. When the oil pump is lowered into a large slope section or a horizontal section, there is a serious eccentric wear problem on the rod and pipe, and the working life is short; 2. Although conventional servo or solenoid valve controlled hydraulic oil and gas recovery systems can solve the problem of eccentric wear of rods and pipes, they cannot realize pumping without moving the pipe string, and have problems such as high operating costs and inconvenient management; 3. The operating costs of ground equipment are high.

[0004] The above technologies are not suitable for solving the problem of economical and efficient development of highly deviated wells (with an inclination exceeding 60°) in heavy oil development.

[0005] Therefore, a hydraulic lifting technology for oil and gas production by steam injection in a fixed pipe string is proposed. Summary of the invention

[0006] The purpose of the present invention is to solve the problems raised in the above-mentioned background technology. The present invention provides a hydraulic lifting process for oil and gas production by steam injection in a fixed pipe column. The process has two liquid flow channels. One liquid flow channel is a cavity between a small oil pipe, an inner cavity of a double-sealed cannula, a small piston of a hydraulic lifting device, an inlet and outlet joint, and a small hydraulic cylinder and a large hydraulic cylinder and a small piston; the other is an annulus between a large oil pipe and a small oil pipe, an upper and lower bridge channel in a bridge joint, an annulus between an outer pipe of a hydraulic lifting device and a hydraulic lifting device, and an annulus between a connecting rod and a large pump barrel; when steam injection is required, the small pipe is lifted up to make the sealing core of the double-sealed cannula escape from the inner core of the double-sealed cannula and the sealed outer pipe, enter the annulus of the oil casing from the lateral channel of the bridge channel, and then enter the formation. The process is suitable for application in high-angle wells, cluster wells, horizontal wells, etc. in the development of steam-throwing heavy oil.

[0007] In order to achieve the above-mentioned purpose, the present invention specifically adopts the following technical solutions: A fixed pipe column steam injection oil and gas hydraulic lifting process, the working process of the fixed pipe column steam injection oil and gas hydraulic lifting process comprises the following steps: S1: Ground work phase, composition and function of ground equipment; S2: The underground working stage is divided into the oil pumping process and the steam injection process. The oil pumping process can be divided into two stages: the upstroke and the downstroke.

[0008] Furthermore, the ground equipment includes a solenoid valve, a ground pump, a frequency converter, a storage tank, a control part, and a ground connecting pipeline, and is characterized in that the ground pump is connected to the storage tank through a pipeline, the ground pump is responsible for pressurizing the power fluid transported from the storage tank and injecting it into the well, the frequency converter adjusts the speed of the ground pump, the storage tank is mainly used to store the power fluid, the control part mainly controls the movement of the motor and the ground pump, and adjusts the pressure and displacement through the frequency converter, and the ground connecting pipeline is used to connect the storage tank with the wellhead sealing device.

[0009] Furthermore, the downhole equipment includes a dual-channel structure consisting of a sealed and adjusted wellhead device, a small oil pipe, a large oil pipe, a bridge joint, a hydraulic lifting device, an inlet and outlet liquid joint, a connecting rod, a feedback oil pump, and a double-sealed insert, a packer and a casing placed in the dual channel. The small oil pipe is connected to the ground pipeline through a sealed and adjusted wellhead device, and the small oil pipe is connected to the hydraulic lifting device through a bridge joint. The upper end of the bridge joint is connected with a double-sealed insert, and the lower end of the bridge joint is connected to an outer tube of a hydraulic lifting device and a small piston of a hydraulic lifting device. The lower end of the hydraulic lifting device is connected to an upper end of a connecting rod, and the lower end of the connecting rod is connected to a plunger of a feedback oil pump. The lower end of the feedback oil pump is connected to a tail pipe, and the outer sleeve of the large oil pipe is provided with a casing, and the packer is located between the large oil pipe and the casing.

[0010] Furthermore, the small oil pipe is connected and sealed with the large oil pipe through a double-sealed cannula, and the double-sealed cannula is composed of a sealed inner core, a sealed outer tube and a sealed core.

[0011] Furthermore, the central holes of the floating valve and the fixed valve of the feedback oil pump are composed of 2 to 6 cylinders, and the 2 to 6 small cylinders cut a large cylindrical surface in the middle into 2 to 6 segments of spatial arc surfaces, and the large cylinder in the middle cuts the 2 to 6 small cylindrical surfaces into only one segment of arc surface.

[0012] Furthermore, when pumping oil, the small oil pipe is lowered, and the length of the small oil pipe is adjusted using the short section of the small oil pipe so that the bottom sealing insert of the small oil pipe just reaches the sealing position.

[0013] Furthermore, during the steam injection, the wellhead sealing device is removed, the small oil pipe is lifted up, the double-sealed insert is removed from the sealing inner core and the sealing outer pipe, and the liquid between the small oil pipe and the large oil pipe flows into the wellbore and the formation through the lateral liquid flow channel of the bridge joint, thereby reducing the viscosity of the crude oil.

[0014] The beneficial effects of the present invention are as follows: The present invention adopts a frequency converter to adjust the frequency, and when the downhole plunger reaches the upper and lower dead points, the electromagnetic valve is quickly switched to improve the operating efficiency of the downhole feedback pump; a dual-channel structure is adopted, and the power fluid enters the hydraulic lifting device from the small oil pipe, and the hydraulic lifting device drives the connecting rod to move upward, driving the plunger of the feedback oil pump to move upward, at this time, the floating valve of the feedback oil pump is closed, the volume of the pump's suction chamber is increased, and the liquid is fed into the fixed valve to enter the suction chamber to complete the liquid feeding. When the ground motor stops working, the hydraulic lifting device moves downward under the action of the hydraulic feedback pump at its bottom, and the power fluid flows back to the storage tank from the small oil pipe and the ground pump to complete the resetting of the hydraulic lifting device. In this reciprocating manner, the crude oil is sucked. Since there is no sucker rod There is no extension and shortening of the sucker rod. At the same time, when the tubing is extended and shortened, the feedback pump also extends and shortens, which prolongs the effective stroke of the feedback pump and improves the effective displacement of the pump; the double-sealed cannula adopts a combination of an inner core, a core and a sealed outer tube, all of which adopt rigid sealing, and have the advantages of high sealing reliability and long service life; the bridge joint adopts a special three-cross structure, which together with the double-sealed cannula realizes the inflow and outflow of power fluid, well fluid and steam injection, and is suitable for use in heavy oil wells with steam injection without moving the tubing string; the ground wellhead sealing device can adjust the length of the small oil pipe to achieve high-pressure leakage-free sealing, which is beneficial to environmental protection. In summary, it can effectively increase the depth of the pump, thereby fully tapping the production potential of the oil well. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a structural flow chart of the hydraulic lifting process of oil production by steam injection in a fixed pipe column of the present invention; Figure 2 It is a schematic diagram of the structure of the present invention; Figure 3 It is a schematic cross-sectional view of the bridge joint at position AA of the present invention; Figure 4 It is a cross-sectional schematic diagram of the floating valve and the fixed valve of the feedback oil pump 14 at BB of the present invention.

[0016] Figure numerals: 1. valve; 2. surface pump; 3. frequency converter; 4. storage tank; 5. wellhead sealing adjustment device; 6. wellhead; 7. small oil pipe; 8. large oil pipe; 9. double-seal cannula; 10. bridge joint; 11. hydraulic lifting device; 12. inlet and outlet liquid joints; 13. connecting rod; 14. feedback oil pump; 15. tail pipe; 16. packer; 17. casing. DETAILED DESCRIPTION

[0017] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0018] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0019] It should be noted that similar reference numerals and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further defined and explained in the subsequent drawings. In addition, the terms "first", "second", etc. are only used to distinguish the description and cannot be understood as indicating or implying relative importance.

[0020] In the description of the embodiments of the present invention, it should be noted that the terms "inside", "outside", "upper", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, or are the orientations or positional relationships in which the inventive product is usually placed when used. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0021] like Figure 1 , Figure 2 , Figure 3 , Figure 4 As shown, a fixed pipe column steam injection oil and gas hydraulic lifting process, the working process of the fixed pipe column steam injection oil and gas hydraulic lifting process includes the following steps: S1: Ground work phase, composition and function of ground equipment; S2: Downhole working stage, divided into oil pumping process and steam injection process, the oil pumping process can be divided into two stages: upstroke and downstroke; specifically, it includes solenoid valve 1, ground pump 2, inverter 3, storage tank 4, control part, ground connecting pipeline, sealing and adjusting wellhead device 5, small oil pipe 7, large oil pipe 8, double-sealed cannula 9, bridge joint 10, hydraulic lifting device 11, inlet and outlet liquid joint 12, connecting rod 13, feedback type oil pump 14 composed of double-channel structure and double-sealed cannula 9 placed in the double channel, the ground pump 2 adopts high-strength pump shaft design, the ground pump 2 and the motor 3 are rigidly connected by a high-strength shaft, the motor drives the ground pump 2 to work, and the ground pump frequency is adjusted by the inverter 3, there is a small oil pipe in the large oil pipe 8, forming two independent liquid flow channels, the small oil pipe 7 is sealed with the inner cavity of the large oil pipe 8 through the double-sealed cannula 9, and the small oil pipe 7 is responsible for delivering the boosted power fluid of the ground pump 2 to the hydraulic The lifting device 11, the hydraulic lifting device 11 provides the power required for the movement of the feedback oil pump 14. The feedback oil pump 14 can not only pump crude oil, but also can make the hydraulic lifting device 11 move downward. The bridge joint 10 has three liquid flow channels, one is the discharge channel for the crude oil pumped from the lower feedback oil pump 14, one is the inlet and outlet channel of the power fluid, and the other is the oil casing annulus connection channel. When the hydraulic lifting device 11 works normally, the double-sealed cannula 9 seals the oil casing annulus channel. When steam injection or oil leakage is required, the small oil pipe 7 is lifted up to make the double-sealed cannula 9 detach from the inner core and outer pipe of the sealing cavity, enter the oil casing annulus from the annulus formed by the inner core and outer pipe of the double-sealed cannula 9, and then inject into the formation. The present invention is mainly used for steam injection and oil and gas production of steam-huffing fixed pipe strings during heavy oil production, and is suitable for use in directional wells, cluster wells, horizontal wells, and steam-huffing heavy oil wells with eccentric wear of rods and pipes.

[0022] like Figure 2 As shown, the ground equipment includes a solenoid valve 1, a ground pump 2, a frequency converter 3, a storage tank 4, a control part, and a ground connecting pipeline, characterized in that the ground pump 2 is connected to the storage tank 4 through a pipeline, specifically, the ground pump 2 is responsible for pressurizing the power fluid transported from the storage tank 4 and injecting it into the small downhole oil pipe 7, thereby driving the large and small hydraulic cylinders to move upward, the frequency converter 3 adjusts the speed of the ground pump 2 to achieve rapid pressure increase and pressure reduction of the power fluid, the storage tank 4 is mainly used to store the power fluid, the control part is mainly to control the movement of the motor and the ground pump 2, and adjusts the pressure and displacement through the frequency converter 3, thereby achieving the injection of power fluid with different displacements and different lifts, the ground connecting pipeline is used to connect the storage tank with the wellhead sealing device, the ground solenoid valve and the ground pump 2 cooperate to achieve the entry and exit of the downhole power fluid, thereby achieving the up and down movement of the downhole piston and the operation of the feedback pump.

[0023] like Figure 2As shown, the downhole equipment includes a double-channel structure consisting of a sealing and regulating wellhead device 5, a small oil pipe 7, a large oil pipe 8, a bridge joint 10, a hydraulic lifting device 11, an inlet and outlet liquid joint 12, a connecting rod 13, and a feedback oil pump 14, and a double-sealed cannula 9, a packer 16 and a casing 17 placed in the double channel. The small oil pipe 7 is connected to the ground pipeline through the sealing and regulating wellhead device 5, and the small oil pipe 7 is connected to the hydraulic lifting device 11 through the bridge joint 10. The upper end of the bridge joint 10 is connected with the double-sealed cannula 9, and the lower end of the bridge joint 10 is connected to the outer tube of the hydraulic lifting device 11 and the small piston of the hydraulic lifting device 11. The lower end of the hydraulic lifting device 11 is connected to the upper end of the connecting rod 13, and the lower end of the connecting rod 13 is connected to the plunger of the feedback oil pump 14. The lower end of 14 is connected to the tail pipe 15, the outer side of the large oil pipe 8 is provided with a casing 17, and the packer 16 is located between the large oil pipe 8 and the casing 17; specifically, during the oil pumping process, the upward stroke: the ground pump 2 injects the power fluid of the ground storage tank 4 from the small oil pipe 7 through the ground pipeline into the small piston inner cavity of the hydraulic lifting device 11, pushing the hydraulic cylinder of the hydraulic lifting device 11 to move upward, the hydraulic cylinder drives the connecting rod to move upward, and the connecting rod drives the plunger of the feedback type oil pump 14 to move upward, the volume of the cavity (suction cavity) between the large plunger, the small plunger and the large pump barrel of the feedback type oil pump 14 increases, the pressure in the cavity decreases, the floating valve of the feedback type oil pump 14 is closed, and under the action of the sinking pressure, the fixed valve is opened, and the liquid entering from the tail pipe 15 flows into the suction cavity to complete the liquid suction process.

[0024] Down stroke: When the hydraulic cylinder of the hydraulic lifting device 11 reaches the top dead center, the ground pump 2 stops working. Since the liquid pressure in the large oil pipe 8 is much greater than the oil and sleeve annulus pressure, under the action of the liquid pressure in the large oil pipe 8, the large and small plungers of the plunger pump 14 of the feedback oil pump move downward, the liquid pressure in the suction chamber increases, the floating valve opens, the fixed valve closes, and the liquid in the suction chamber is discharged into the oil pipe to complete the discharge.

[0025] During the upstroke, since the floating valve of the feedback oil pump 14 is closed, the liquid column load of the feedback oil pump 14 is the product of the cross-sectional area of ​​the large plunger and the liquid pressure on the upper part of the large plunger. That is to say, the liquid column load of the pump during the upstroke is equal to the liquid column load of an ordinary conventional tube pump with the same pump diameter.

[0026] During the downstroke, since the floating valve of the feedback oil pump 14 is opened and the fixed valve is closed, the upper end surface of the small plunger 14 of the feedback oil pump acts on a downward hydraulic force to help the small plunger move downward and overcome the downward resistance of the large and small hydraulic cylinders.

[0027] like Figure 2As shown, the small oil pipe 7 and the large oil pipe 8 are connected and sealed by a double-sealed cannula 9, and the double-sealed cannula 9 is composed of a sealing inner core, a sealing outer tube and a sealing core; specifically, the sealing inner core is one of the key parts of the double-sealed cannula, which is usually located inside and plays a major role in sealing and fluid guiding. The sealing outer tube mainly plays a role in protection and auxiliary sealing. It is wrapped around the outside of the sealing inner core to form a double-layer sealing structure. The sealing core is a component that further enhances the sealing performance. It can be a special sealing element made of rubber or polymer material, which is installed between the sealing inner core and the sealing outer tube or at a specific position of the sealing inner core.

[0028] like Figure 3 , Figure 4 As shown, the central holes of the floating valve and the fixed valve of the feedback oil pump 14 are composed of 2 to 6 cylinders, and the 2 to 6 small cylinders cut a large cylindrical surface in the middle into 2 to 6 segments of space arc surfaces, and the large cylinder in the middle cuts the 2 to 6 small cylindrical surfaces into only one segment of arc surface; specifically, it is obvious that the floating valve ball and the fixed valve ball can only move up and down in the large cylinder in the middle, and are straightened by the cut 2 to 6 segments of arc surfaces, and the liquid passes through the gap between the 2 to 6 small cylindrical surfaces and the floating valve ball and the fixed valve ball. Since the floating valve ball and the fixed valve ball can only move up and down and cannot deviate to the side, they can quickly return to the floating valve seat and the fixed valve seat by relying on their gravity, thereby reducing the movement time of the sucker rod after the valve ball is opened and closed, which is beneficial for working in inclined wells.

[0029] like Figure 2 As shown, when pumping oil, the small oil pipe 7 is lowered, and the length of the small oil pipe 7 is adjusted by using the short section of the small oil pipe 7, so that the bottom sealing insert of the small oil pipe 7 just reaches the sealing position; specifically, a good seal is achieved. During the oil pumping process, the downhole environment is complex, and there are crude oil, natural gas and various possible formation fluids. The double sealing insert 9 in this position can prevent these fluids from leaking in the annular space between the small oil pipe 7 and the surrounding casing or other downhole equipment, and can accurately guide the fluid.

[0030] like Figure 2As shown, when injecting steam, the wellhead sealing device is removed, the small oil pipe 7 is lifted up, and the double-sealed cannula 9 is removed from the sealed inner core and the sealed outer tube, and the liquid between the small oil pipe 7 and the large oil pipe 8 flows into the wellbore through the lateral liquid flow channel of the bridge joint 10; specifically, the wellhead sealing device is removed and the small oil pipe 7 is lifted up in order to start the steam injection process. In the normal oil pumping stage, the small oil pipe 7 and its double-sealed cannula 9 are in a sealed position and are mainly used for oil pumping. When injecting steam, it is necessary to change the fluid state downhole, and the double-sealed cannula 9 is removed from the sealed inner core and the sealed outer tube by lifting the small oil pipe 7. In this way, a new liquid channel can be opened to prepare for steam injection, allowing the liquid between the small oil pipe 7 and the large oil pipe 8 to flow into the wellbore through the lateral liquid flow channel of the bridge joint 10. This step is mainly to inject steam into the formation, reduce the viscosity of crude oil, and facilitate the crude oil in the formation to enter the wellbore; the packer is used to seal the injected steam in the oil and casing annulus below the packer to prevent the steam from being lost in the upper casing of the packer and affecting the steam injection effect. At the same time, it can also protect the casing so that the first and second interfaces of the casing are not damaged during the injection process, thereby protecting the casing.

[0031] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions only describe the principles of the present invention. The present invention may be subject to various changes and improvements without departing from the spirit and scope of the present invention. These changes and improvements fall within the scope of the present invention. The scope of protection claimed by the present invention is defined by the attached claims and their equivalents.

Claims

1. A process for hydraulic lifting of oil and gas produced by injecting steam into a fixed pipe column, the working process of which comprises the following steps: S1: Ground work phase, composition and function of ground equipment; S2: The underground working stage is divided into the oil pumping process and the steam injection process. The oil pumping process can be divided into two stages: the upstroke and the downstroke.

2. The method for hydraulic lifting of oil production by steam injection in a fixed pipe column according to claim 1, characterized in that: The surface equipment comprises a solenoid valve (1), a surface pump (2), a frequency converter (3), a storage tank (4), a control part, and a surface connection pipeline, wherein the surface pump (2) is connected to the storage tank (4) via a pipeline, the surface pump (2) is responsible for pressurizing the power fluid transported from the storage tank (4) and injecting it into the well, the frequency converter (3) adjusts the rotation speed of the surface pump (2), the storage tank (4) is mainly used to store the power fluid, the control part is mainly used to control the movement of the motor and the surface pump, and the pressure and displacement are adjusted by the frequency converter (3), and the surface connection pipeline is used to connect the storage tank (4) with the wellhead sealing device.

3. The method for hydraulic lifting of oil production by steam injection in a fixed pipe column according to claim 1, characterized in that: The downhole equipment comprises a double-channel structure consisting of a sealing and regulating wellhead device (5), a small oil pipe (7), a large oil pipe (8), a bridge joint (10), a hydraulic lifting device (11), an inlet and outlet fluid joint (12), a connecting rod (13), and a feedback oil pump (14), and a double-sealed cannula (9), a packer (16), and a casing (17) arranged in the double channel. The small oil pipe (7) is connected to the surface pipeline through the sealing and regulating wellhead device (5), and the small oil pipe (7) is connected to the hydraulic lifting device (11) through a bridge joint connection (10). The bridge joint (13) is connected to the hydraulic lifting device (11) through a bridge joint connection (10). The upper end of the bridge joint (10) is connected to a double-sealed insert (9), the lower end of the bridge joint (10) is connected to an outer tube of a hydraulic lifting device (11) and a small piston of the hydraulic lifting device (11), the lower end of the hydraulic lifting device (11) is connected to an upper end of a connecting rod (13), the lower end of the connecting rod (13) is connected to a plunger of a feedback oil pump (14), the lower end of the feedback oil pump (14) is connected to a tail pipe (15), the outer part of the large oil pipe (8) is provided with a casing (17), and the packer (16) is located between the large oil pipe (8) and the casing (17).

4. The method for hydraulic lifting of oil production by steam injection in a fixed pipe column according to claim 3 is characterized in that: The small oil pipe (7) and the large oil pipe (8) are connected and sealed via a double-sealed insert (9), wherein the double-sealed insert (9) is composed of a sealed inner core, a sealed outer tube and a sealed core.

5. The method for hydraulic lifting of oil production by steam injection in a fixed pipe column according to claim 3 is characterized in that: The central holes of the floating valve and the fixed valve of the feedback oil pump (14) are composed of 2 to 6 cylinders, wherein the 2 to 6 small cylinders cut a large cylindrical surface in the middle into 2 to 6 segments of spatial arc surfaces, and the large cylinder in the middle cuts the 2 to 6 small cylindrical surfaces into only one segment of arc surface.

6. The method for hydraulic lifting of oil production by steam injection in a fixed pipe column according to claim 3 is characterized in that: When pumping oil, the small oil pipe (7) is lowered, and the length of the small oil pipe (7) is adjusted using the short section of the small oil pipe (7) so that the bottom sealing insert of the small oil pipe (7) just reaches the sealing position.

7. The method for hydraulic lifting of oil production by steam injection in a fixed pipe column according to claim 3 is characterized in that: During steam injection, the wellhead sealing device is removed, the small oil pipe (7) is lifted up, the double-sealed insert (9) is removed from the sealing inner core and the sealing outer pipe, and the liquid between the small oil pipe (7) and the large oil pipe (8) flows into the wellbore through the lateral liquid flow channel of the bridge joint (10).

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