A downhole gas-liquid separation jet drainage process string and process method

Abstract

The present invention proposes a downhole gas-liquid separation jet drainage process string and process method. The process string includes a small oil pipe, an oil pipe, and a casing that are sequentially sleeved from the inside to the outside. There is an annular space between the oil pipe and the casing, and the annular space is provided with a packer; the lower end of the small oil pipe is sequentially connected to a jet pump, a gas-liquid separator, and a check valve. When performing jet drainage operations, working fluid is injected from the small oil pipe. The working fluid forms a negative pressure zone in the oil pipe through the jet pump. The gas-liquid mixed fluid at the bottom of the well enters the gas-liquid separator through the check valve. The gas-liquid separator starts working under the action of the upper working fluid, wherein the liquid enters the oil pipe through the drainage channel on the side of the gas-liquid diverter; the gas enters the annular space between the oil pipe and the casing through the exhaust channel at the bottom of the gas-liquid diverter, thereby achieving gas-liquid separation. The downhole gas-liquid separation jet drainage process disclosed by the present invention can achieve separation of gas and liquid and rapid drainage, thereby improving the jet drainage effect of water-producing gas wells.

Description

Technical Field

[0001] The invention belongs to the technical field of oil and gas field development, and particularly relates to a downhole gas-liquid separation jet drainage process string and a process method. Background Art

[0002] As gas reservoir development progresses, more and more gas wells are producing liquids, with increasing rates of production. This increased production leads to liquid accumulation in the wellbore, increased backpressure, decreased wellhead pressure, and a serious impact on gas well production capacity. Water intrusion and water lock in the gas-producing layer severely impact gas well production and ultimate recovery. Therefore, minimizing the impact of bottomhole liquid accumulation on gas well production, separating gas and liquid at the bottom, and promptly recovering the produced liquid to the surface have become critical steps in the gas well production process.

[0003] The key to achieving gas-liquid separation lies in establishing a gas-liquid separation channel. For example, patent CN104047588A discloses a downhole gas-liquid separation string. This string includes a packer, a connecting channel, a pumping pipe, an oil hole, a conversion joint, and a pumping pump. The connecting channel is located inside the pumping pipe, and an oil inlet is opened in the wall of the pumping pipe above the packer. After the gas-liquid mixture flows through the connecting channel and enters the casing annulus, gas-liquid separation is achieved due to the gas slippage effect. After separation, the gas flows to the surface through the casing annulus, while the liquid sinks and enters the annulus between the connecting channel and the pumping pipe through the oil hole. It then enters the pump cavity of the pumping pump through the conversion joint and is pumped to the surface for production. This process string has low gas-liquid separation efficiency, and the rich gas flow after separation contains a large amount of liquid, which still poses the risk of liquid accumulation.

[0004] Patent CN109057755A discloses a downhole cyclonic gas-liquid separation string, which includes a cyclonic gas-liquid separator, an electric pump unit, a velocity tube, and a blender. The electric pump unit is externally connected to the oil casing annulus, the cyclonic gas-liquid separator is located below the electric pump unit, and the blender is located above the velocity tube. After the gas-liquid mixture is separated by the cyclonic gas-liquid separator, the gas enters the velocity tube, and the liquid enters the oil casing annulus. After being pressurized and pumped by the electric pump unit, it enters the annulus between the velocity tube and the oil pipe. Furthermore, the gas and liquid are mixed in the blender above the velocity tube, and the mixed fluid is lifted to the surface. The purpose of this process string is to achieve gas-liquid separation downhole. The separated liquid is pressurized by a booster device as lifting energy to lift the gas to the surface. Ultimately, it is still gas-liquid co-production, not true gas-liquid separation.

[0005] Patent CN207017952U provides a downhole gas-liquid separation lifting process string, but the gas-liquid separation system and the canned electric pump oil production system of the process string are both located above the packer, which cannot completely drain the accumulated liquid below the packer. It is difficult to meet the drainage and gas production needs of low-pressure, large-liquid-volume wells. In addition, the structure of the process string shows that there is only a single flow channel below the packer, and gas and liquid are produced together without separation.

[0006] Therefore, the currently commonly used drainage and production process strings cannot achieve downhole gas-liquid separation, resulting in incomplete drainage and production effects. Summary of the Invention

[0007] The purpose of the present invention is to provide a downhole gas-liquid separation jet drainage process pipe string and process method, so as to realize downhole gas-liquid separation and jet drainage gas production, and improve the gas production of gas wells.

[0008] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0009] A downhole gas-liquid separation jet drainage process string includes a small oil pipe, an oil pipe, and a casing which are sequentially arranged from the inside to the outside. There is an annular space between the oil pipe and the casing. The annular space is provided with a packer for sealing the annular space between the oil pipe and the casing in the upper part of the perforated well section. It is characterized in that the lower end of the small oil pipe is sequentially connected to a jet pump, a gas-liquid separator, and a check valve.

[0010] Furthermore, the jet pump includes a working fluid conduit, a central jet nozzle, an annular jet nozzle, a suction chamber, a throat, a diffuser, a mixed fluid outlet and an ejection fluid conduit. The suction chamber, throat, diffuser and mixed fluid outlet are connected in sequence, the ejection fluid conduit is connected to the suction chamber, the annular jet nozzle is sleeved outside the central jet nozzle, and the inlets of the annular jet nozzle and the central jet nozzle are respectively connected to the working fluid conduit, the outlet of the annular jet nozzle is flush with the outlet of the central jet nozzle and is arranged in the suction chamber.

[0011] Furthermore, an annular fluid channel is provided between the annular jet nozzle and the central jet nozzle, and the ejection fluid conduit is communicated with the suction chamber through the annular fluid channel.

[0012] Preferably, a central jet nozzle control valve is installed on the working fluid conduit on the upstream side of the central jet nozzle to control the injection state of the central jet nozzle; an annular jet nozzle control valve is installed on the working fluid conduit on the upstream side of the annular jet nozzle to control the injection state of the annular jet nozzle.

[0013] Furthermore, the gas-liquid separator includes a cylinder, a center rod, a swirl wheel, and a diverter joint. The center rod is a hollow structure with openings at both ends. The upper end of the center rod is connected to the cylinder, and the lower end of the center rod is connected to the swirl wheel and the diverter joint in sequence; an air outlet is coaxially provided at the center of the diverter joint, and a liquid outlet is provided on the outside; a drainage channel is provided on the side of the cylinder, and the drainage channel is connected to the oil pipe. An exhaust channel is provided at the bottom of the cylinder, and the air outlet is preferably provided opposite to the exhaust channel, and the exhaust channel is connected to the annular space between the oil pipe and the casing.

[0014] Furthermore, the swirl wheel is provided with a spiral wheel blade, and a gap is provided between the swirl wheel and the diversion joint.

[0015] Furthermore, a gap is provided between the outer wall of the diversion joint and the inner wall of the cylinder.

[0016] Furthermore, the diverter joint includes an annular flange portion and an inverted cone body arranged below the annular flange portion, a plurality of liquid outlet holes are arranged at intervals on the outer circumference of the annular flange portion, and a drainage channel on the side of the cylinder body is arranged below the liquid outlet holes.

[0017] Furthermore, the annular flange portion and the inverted frustum body are coaxially arranged, and the annular flange portion and the inverted frustum body are both hollow inside and interconnected to form an air outlet.

[0018] A downhole gas-liquid separation and jet drainage process method comprises the following steps:

[0019] S1, after perforating and fracturing the target well section, the fracturing string is pulled out of the well;

[0020] S2: Run the tubing down, lower the tubing with the packer into the upper part of the perforated section, set the packer to seal the annulus between the tubing and casing; then connect the small tubing to the jet pump, gas-liquid separator, and check valve in sequence, and run it down into the tubing;

[0021] S3, perform jet drainage operation: inject working fluid from the small oil pipe, the working fluid forms a negative pressure area in the oil pipe through the jet pump, and the gas-liquid mixed fluid at the bottom of the well enters the gas-liquid separator through the one-way valve. The gas-liquid separator starts to work under the action of the upper working fluid, and the liquid enters the oil pipe through the drainage channel on the side of the gas-liquid diverter; the gas enters the annular space between the oil pipe and the casing through the exhaust channel at the bottom of the gas-liquid diverter, realizing gas-liquid separation.

[0022] Furthermore, the specific working process of the gas-liquid separator is as follows: the working fluid enters the cylinder of the gas-liquid separator, passes through the fluid channel of the center rod, drives the swirl wheel to rotate to form a swirl, and the liquid flows downward along the inner wall of the cylinder of the gas-liquid separator, and then enters the liquid outlet of the diverter joint, and enters the oil pipe through the drainage channel on the side of the gas-liquid separator, and finally discharged from the wellbore; the gas is concentrated in the middle of the inner cavity of the gas-liquid separator, and then discharged to the outside of the diverter joint through the air outlet, and enters the annular space between the oil pipe and the casing through the exhaust channel at the bottom of the gas-liquid separator, and finally discharged from the wellbore.

[0023] The beneficial effects of the present invention are:

[0024] (1) By optimizing the process string and process equipment, downhole gas-liquid separation and jet drainage are achieved, the downhole fluid drainage efficiency is improved, and the production operation cost is reduced.

[0025] (2) The jet pump of the present invention is provided with a central jet nozzle and an annular jet nozzle. The working fluid carries the sucked liquid inside and outside the center and the circumference respectively, which will significantly increase the suction capacity of the sucked liquid, thereby improving the efficiency of the jet pump.

[0026] (3) The present invention controls the central jet and the annular jet respectively through the central jet nozzle control valve and the annular jet nozzle control valve, thereby improving the operating performance of the jet pump.

[0027] (4) The gas-liquid separator of the present invention has a simple structure and low cost. When the liquid passes through, it drives the cyclone wheel to rotate, causing the liquid to generate centrifugal force and swirl along the wall in the inner cavity. The liquid in the gas is concentrated in the center, and then the liquid and gas flow out through the outer drainage channel and the central air outlet channel respectively, realizing gas-liquid separation.

[0028] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention and implement it according to the contents of the specification, the following is a detailed description of the preferred embodiments of the present invention with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other design solutions and drawings can be obtained based on these drawings without paying any creative work.

[0030] Figure 1 This is a schematic diagram of the downhole gas-liquid separation jet drainage process string and process principle of the present invention;

[0031] Figure 2 It is a structural diagram of the jet pump;

[0032] Figure 3 It is a schematic diagram of the nozzle structure;

[0033] Figure 4 It is a structural diagram of the gas-liquid separator.

[0034] Description of reference numerals:

[0035] 1. Casing; 2. Oil pipe; 3. Small oil pipe; 4. Jet pump; 4-1. Working fluid conduit; 4-2. Central jet nozzle; 4-3. Annular jet nozzle; 4-4. Suction chamber; 4-5. Throat; 4-6. Diffuser; 4-7. Mixed fluid outlet; 4-8. Injection fluid conduit; 5. Gas-liquid separator; 5-1. Cylinder; 5-2. Fixed center rod; 5-3. Swirl wheel; 5-4. Diverter joint; 5-5. Liquid outlet; 5-6. Liquid drainage channel; 5-7. Air outlet; 5-8. Exhaust channel; 6. Check valve; 7. Packer; 8. Target well section.

[0036] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments. DETAILED DESCRIPTION

[0037] Example 1

[0038] Reference Figure 1 The present invention provides a downhole gas-liquid separation jet drainage process string, comprising a small oil pipe 3, a tubing 2, and a casing 1, which are sequentially arranged from the inside out. An annular space is defined between the tubing 2 and the casing 1. A packer 7 is provided in the annular space for isolating the annular space between the tubing 2 and the casing 1 at the upper portion of the perforated well section. The string is characterized in that the lower end of the small oil pipe 3 is sequentially connected to a jet pump 4, a gas-liquid separator 5, and a check valve 6. It is worth noting that the check valve is provided in the present invention to allow only bottomhole liquid to flow in, preventing upper working fluid from flowing to the bottom of the well.

[0039] The present invention also proposes an underground gas-liquid separation jet drainage process method, which includes the following steps:

[0040] S1, after perforating and fracturing the target well section 8, the fracturing string in the well is pulled out;

[0041] S2: Run the tubing 2 down. The tubing 2 with the packer 7 is lowered into the upper part of the perforated section. The packer 7 is set to seal the annular space between the tubing 2 and the casing 1. Then, the small tubing 3 is connected to the jet pump 4, the gas-liquid separator 5, and the check valve 6 in sequence and lowered into the tubing 2.

[0042] S3, perform jet drainage operation: inject working fluid from the small oil pipe 3, the working fluid forms a negative pressure area in the oil pipe 2 through the jet pump 4, and the gas-liquid mixed fluid at the bottom of the hole enters the gas-liquid separator 5 through the check valve 6. The gas-liquid separator 5 starts to work under the action of the upper working fluid, wherein the liquid enters the oil pipe 2 through the drainage channel 5-6 on the side of the gas-liquid diverter 5; the gas enters the annular space between the oil pipe 2 and the casing 1 through the exhaust channel 5-8 at the bottom of the gas-liquid diverter 5, realizing downhole gas-liquid separation and jet drainage, and improving the downhole fluid drainage efficiency.

[0043] Example 2

[0044] On the basis of Example 1, further, referring to Figure 2 、 Figure 3 The jet pump 4 includes a working fluid conduit 4-1, a central jet nozzle 4-2, an annular jet nozzle 4-3, a suction chamber 4-4, a throat 4-5, a diffuser 4-6, a mixed fluid output port 4-7 and an ejection fluid conduit 4-8. The suction chamber 4-4, the throat 4-5, the diffuser 4-6 and the mixed fluid output port 4-7 are connected in sequence. The ejection fluid conduit 4-8 is connected to the suction chamber 4-4. The annular jet nozzle 4-3 is sleeved outside the central jet nozzle 4-2, and the inlets of the annular jet nozzle 4-3 and the central jet nozzle 4-2 are respectively connected to the working fluid conduit 4-1. The outlet of the annular jet nozzle 4-3 is flush with the outlet of the central jet nozzle 4-2 and is arranged in the suction chamber 4-4.

[0045] Furthermore, an annular fluid channel is provided between the annular jet nozzle 4-3 and the central jet nozzle 4-2, and the ejection fluid conduit 4-8 is connected to the suction chamber 4-4 through the annular fluid channel.

[0046] The jet pump first ejects the working fluid through the nozzle at high speed, thereby forming a low-pressure area at the nozzle outlet, and the guided fluid is sucked into the jet pump; then the working fluid and the guided fluid are mixed in the throat pipe and momentum exchange occurs, the working fluid velocity decreases, the guided fluid velocity increases, and the velocities of the two fluids tend to be consistent at the throat pipe outlet; after the mixed fluid passes through the diffuser, the flow velocity gradually decreases and the pressure rises, and finally it is discharged from the mixed fluid output port.

[0047] Example 3

[0048] On the basis of Example 2, further, a central jet nozzle control valve is installed on the working fluid conduit 4-1 on the upstream side of the central jet nozzle 4-2 to control the injection state of the central jet nozzle 4-2; and an annular jet nozzle control valve is installed on the working fluid conduit 4-1 on the upstream side of the annular jet nozzle 4-3 to control the injection state of the annular jet nozzle 4-3.

[0049] Specifically, when the central jet nozzle control valve is open and the annular jet nozzle control valve is closed, the jet pump of the present invention can operate as a central jet pump. When the central jet nozzle control valve is closed and the annular jet nozzle control valve is open, the jet pump of the present invention can operate as an annular jet pump. When both the central jet nozzle control valve and the annular jet nozzle control valve are open, the jet pump operates as a composite jet pump. Therefore, the operating state of the jet pump can be controlled by adjusting the open and closed states of the central jet nozzle control valve and the annular jet nozzle control valve, thereby improving the operating performance of the composite jet pump.

[0050] Example 4

[0051] On the basis of Example 1, further, referring to Figure 4 The gas-liquid separator 5 includes a cylinder 5-1, a center rod 5-2, a swirl wheel 5-3, and a diverter joint 5-4. The center rod 5-2 is a hollow structure with openings at both ends. The upper end of the center rod 5-2 is connected to the cylinder 5-1, and the lower end of the center rod 5-2 is connected to the swirl wheel 5-3 and the diverter joint 5-4 in sequence; the diverter joint 5-4 is coaxially provided with an air outlet 5-7 in the center, and a liquid outlet 5-5 is provided on the outside; a drainage channel 5-5 is provided on the side of the cylinder 5-1, and the drainage channel 5-5 is connected to the oil pipe 2, and the separated liquid enters the oil pipe through the drainage channel; an exhaust channel 5-8 is provided at the bottom of the cylinder 5-1, and the air outlet 5-7 is preferably arranged opposite to the exhaust channel 5-8, and the exhaust channel 5-8 is connected to the annular space between the oil pipe 2 and the casing 1, and the separated gas enters the oil casing annulus through the exhaust channel.

[0052] The specific working process of the gas-liquid separator 5 is as follows: the working fluid enters the cylinder of the gas-liquid separator 5, passes through the fluid channel of the center rod 5-2, drives the swirl wheel 5-3 to rotate to form a swirl, and the liquid flows downward along the inner wall of the cylinder of the gas-liquid separator 5, and then enters the liquid outlet 5-5 of the diverter joint 5-4, and enters the oil pipe 2 through the drainage channel 5-6 on the side of the gas-liquid separator 5, and finally discharged from the wellbore; the gas is concentrated in the middle of the inner cavity of the gas-liquid separator 5, and then discharged to the outside of the diverter joint 5-4 through the gas outlet 5-7, and enters the annular space between the oil pipe 2 and the casing 1 through the exhaust channel 5-8 at the bottom of the gas-liquid separator 5, and finally discharged from the wellbore.

[0053] Example 5

[0054] On the basis of the above embodiment, further, the swirl wheel 5 - 3 is provided with a spiral wheel blade, which can rotate the upper working fluid to form a swirl.

[0055] Furthermore, a gap is provided between the swirl wheel 5-3 and the diverter joint 5-4. Since the working fluid needs to flow a certain distance to completely separate the gas and liquid phases under the action of centrifugal force when forming a swirl, but if the flow distance is too long, the separated gas and liquid phases will remix. Therefore, the distance between the swirl wheel 3 and the diverter joint 5 is set to ensure that the working fluid flows a moderate distance, so that the end of the diverter joint 5 is located at a position where the gas and liquid phases can be completely separated, thereby ensuring the gas-liquid separation effect.

[0056] Example 6

[0057] On the basis of Example 4, further, a gap is provided between the outer wall of the diverter joint 5-4 and the inner wall of the cylinder 5-1. The diverter joint 5-4 includes an annular flange portion and an inverted frustum body provided below the annular flange portion, and a plurality of liquid outlet holes 5-5 are provided at intervals on the outer circumference of the annular flange portion, and a drainage channel 5-5 on the side of the cylinder 5-1 is provided below the liquid outlet holes 5-5. Furthermore, the annular flange portion and the inverted frustum body are coaxially provided, and the annular flange portion and the inverted frustum body are both hollow inside and connected to each other to form an air outlet hole 5-7. The annular flange provided on the diverter joint brings the outer wall of the diverter joint closer to the inner wall of the body, so that the liquid can completely fill the gap between the outer wall of the diverter joint and the inner wall of the cylinder, seal the gap, and prevent gas from entering the drainage channel through the gap, thereby enhancing the air tightness of the device and ensuring the purity of the liquid after gas-liquid separation.

[0058] Example 7

[0059] This embodiment provides a downhole gas-liquid separation jet drainage process method, comprising the following steps:

[0060] S1, after perforating and fracturing the target well section 8, the fracturing string in the well is pulled out;

[0061] S2: Run the tubing 2 down. The tubing 2 with the packer 7 is lowered into the upper part of the perforated section. The packer 7 is set to seal the annular space between the tubing 2 and the casing 1. Then, the small tubing 3 is connected to the jet pump 4, the gas-liquid separator 5, and the check valve 6 in sequence and lowered into the tubing 2.

[0062] S3, perform jet drainage operation: inject working fluid from the small oil pipe 3, the working fluid forms a negative pressure area in the oil pipe 2 through the jet pump 4, and the gas-liquid mixed fluid at the bottom of the hole enters the gas-liquid separator 5 through the check valve 6. Under the action of the upper working fluid, the gas-liquid separator 5 drives the swirl wheel 5-3 to rotate to form a vortex. The liquid flows downward along the inner wall of the diverter 5, then enters the liquid outlet 5-5 of the diverter joint 5-4, and enters the oil pipe 2 through the drainage channel 5-6 on the side of the gas-liquid diverter 5, and is discharged from the wellbore; the gas is concentrated in the middle of the separator cavity, and then discharged to the outside of the diverter joint 5-4 through the gas outlet 5-7, and enters the annular space between the oil pipe and casing through the exhaust channel 5-8 at the bottom of the gas-liquid diverter 5, and is discharged from the wellbore.

[0063] The present invention realizes downhole gas-liquid separation and jet drainage by optimizing the process pipe string and process equipment, thereby improving downhole fluid drainage efficiency and reducing production operation costs.

[0064] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present invention should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims. Components and structures not described in detail in this embodiment are well-known components and commonly used structures or commonly used means in the industry and are not described here one by one.

Claims

1. A downhole gas-liquid separation jet drainage process string, characterized by: The invention comprises a small oil pipe, an oil pipe and a casing which are sequentially arranged from the inside out, an annular space is formed between the oil pipe and the casing, and a packer is provided in the annular space for sealing the annular space between the oil pipe and the casing in the upper part of the perforated well section, and is characterized in that the lower end of the small oil pipe is sequentially connected to a jet pump, a gas-liquid separator and a check valve; The gas-liquid separator includes a cylinder, a center rod, a swirl wheel, and a diverter joint. The center rod is a hollow structure with openings at both ends. The upper end of the center rod is connected to the cylinder, and the lower end of the center rod is connected to the swirl wheel and the diverter joint in sequence. The diverter joint is coaxially provided with an air outlet at the center and a liquid outlet at the outer side. A drainage channel is provided on the side of the cylinder, and the drainage channel is connected to the oil pipe. An exhaust channel is provided at the bottom of the cylinder, and the exhaust channel is connected to the annular space between the oil pipe and the casing. The diverter joint includes an annular flange portion and an inverted frustum provided below the annular flange portion. A plurality of liquid outlet holes are provided at intervals on the outer circumference of the annular flange portion, and a liquid discharge channel on the side of the cylinder body is provided below the liquid outlet holes. The annular flange portion and the inverted frustum body are coaxially arranged, and both the annular flange portion and the inverted frustum body are hollow inside and are interconnected to form an air outlet.

2. The downhole gas-liquid separation jet drainage process string according to claim 1, characterized in that: The swirl wheel is provided with a spiral wheel blade, and a gap is provided between the swirl wheel and the diversion joint.

3. The downhole gas-liquid separation jet drainage process string according to claim 1, characterized in that: A gap is provided between the outer wall of the diversion joint and the inner wall of the cylinder.

4. A method for performing downhole gas-liquid separation jet drainage process using the downhole gas-liquid separation jet drainage process string according to any one of claims 1 to 3, characterized in that: The following steps are involved: S1, after perforating and fracturing the target well section, the fracturing string is pulled out of the well; S2: Run the tubing down, lower the tubing with the packer into the upper part of the perforated section, set the packer to seal the annulus between the tubing and casing; then connect the small tubing to the jet pump, gas-liquid separator, and check valve in sequence, and run it down into the tubing; S3, perform jet drainage operation: inject working fluid from the small oil pipe, the working fluid forms a negative pressure area in the oil pipe through the jet pump, and the gas-liquid mixed fluid at the bottom of the well enters the gas-liquid separator through the one-way valve. The gas-liquid separator starts to work under the action of the upper working fluid, and the liquid enters the oil pipe through the drainage channel on the side of the gas-liquid diverter; the gas enters the annular space between the oil pipe and the casing through the exhaust channel at the bottom of the gas-liquid diverter, realizing gas-liquid separation.

5. The downhole gas-liquid separation jet drainage process according to claim 4, characterized in that: In step S3, the specific working process of the gas-liquid separator is as follows: the working fluid enters the cylinder of the gas-liquid separator, passes through the fluid channel of the center rod, drives the swirl wheel to rotate to form a swirl, and the liquid flows downward along the inner wall of the cylinder of the gas-liquid separator, and then enters the liquid outlet hole of the diverter joint, and enters the oil pipe through the drainage channel on the side of the gas-liquid separator, and finally is discharged from the wellbore; the gas is concentrated in the middle of the inner cavity of the gas-liquid separator, and then is discharged to the outside of the diverter joint through the air outlet hole, and enters the annular space between the oil pipe and the casing through the exhaust channel at the bottom of the gas-liquid separator, and finally is discharged from the wellbore.

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