Gas lift reinjection technology suitable for middle-deep geothermal reinjection well

Abstract

The application provides a gas lift backwashing process suitable for a middle-deep geothermal recharge well, which comprises the following steps: installing a wellhead device on the recharge well, installing a backwashing water treatment equipment, and connecting the wellhead device with the recharge water pipe and the backwashing water treatment equipment respectively, and connecting the backwashing water treatment equipment with other recharge wells; installing a gas lift mechanism on the wellhead device, extending the bottom end of the gas lift mechanism to below the aquifer, and connecting the gas lift mechanism with an air compressor; starting the air compressor, injecting compressed air into the recharge well through the gas lift mechanism, and making the gas-liquid mixture formed in the recharge well carry the blocked impurities to the backwashing water treatment equipment through the wellhead device. The gas lift backwashing process suitable for the middle-deep geothermal recharge well can effectively replace the previous submersible pump, can solve the blockage, can reduce the water lifting amount, can solve the problem that the backwashing water is difficult to treat, and has high practicability.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of recharge of middle-deep geothermal well, and particularly relates to a gas lift backwashing process suitable for middle-deep geothermal recharge well. BACKGROUND

[0002] In the recharge technology of middle-deep geothermal well, the problems of filter pipe itself or pipe blockage can be solved by well washing and acidification. However, once the aquifer around the recharge well is blocked, these methods will not work. Studies have shown that the attenuation of the permeability coefficient during the recharge process is mainly concentrated in the area close to the recharge well, which is commonly known as the "near wellbore zone".

[0003] In the prior art, the method of regular backwashing is usually used to alleviate the physical blockage of the aquifer. Backwashing refers to the pumping work in the recharge well to remove the precipitates in the recharge well and the blockages in the hot reservoir. The backwashing equipment refers to a submersible pump, which uses the submersible pump in the recharge well to pump out the blockages and attachments in the well. In order to achieve the expected backwashing effect, the submersible pump needs to be operated at full frequency during backwashing, and the backwashing water output per hour is at least 80 tons. The backwashing needs to be continued for 3-7 days. The backwashing water cannot be directly recharged into the hot reservoir due to water quality problems. The large amount of water and the problem of recharging water treatment cannot be solved, so the method of backwashing to alleviate the physical blockage of the aquifer has poor practicability. SUMMARY

[0004] The embodiment of the present application provides a gas lift backwashing process suitable for middle-deep geothermal recharge well, which aims to solve the problem of poor practicability of the existing method for alleviating the blockage of the recharge well.

[0005] To achieve the above-mentioned purpose, the technical solution adopted by the present application is as follows: a gas lift backwashing process suitable for middle-deep geothermal recharge well is provided, which comprises the following steps:

[0006] Ground equipment installation, installing wellhead device on the recharge well, and installing backwashing water treatment equipment, the wellhead device is communicated with the recharge water pipe and the backwashing water treatment equipment, and the backwashing water treatment equipment is communicated with other recharge wells;

[0007] Lowering the gas lift module, installing the gas lift mechanism on the wellhead device, extending the bottom end of the gas lift mechanism to the lower part of the aquifer, and connecting the gas lift mechanism with the air compressor;

[0008] Gas lift operation, starting the air compressor, injecting compressed air into the recharge well through the gas lift mechanism, and making the gas-liquid mixture formed in the recharge well carry the blockage impurities into the backwashing water treatment equipment through the wellhead device.

[0009] In a possible implementation, the wellhead device set in the ground equipment installation step includes a wellhead pipe, a sealing cover plate, a branch pipe, an elbow pipe and a water diversion pipe; the wellhead pipe is fixedly installed at the top end of the recharge well; the sealing cover plate is located at the top end of the wellhead pipe and detachably connected with the wellhead pipe; one end of the branch pipe is fixedly connected with the wellhead pipe and communicates with the lumen of the wellhead pipe, and the other end of the branch pipe communicates with the back-swing water treatment equipment, and the branch pipe is provided with a first butterfly valve; one end of the elbow pipe is fixedly connected with the wellhead pipe and communicates with the lumen of the wellhead pipe, and the elbow pipe is provided with a second butterfly valve; the water diversion pipe has two connecting ends, and an interface end is arranged between the two connecting ends, the two connecting ends respectively communicate with the recharge water pipe and the back-swing water treatment equipment, the interface end communicates with the other end of the elbow pipe, the water diversion pipe is provided with a third butterfly valve and a fourth butterfly valve, the third butterfly valve is located on one side of the interface end and is used for controlling the communication between the water diversion pipe and the back-swing water treatment equipment, and the fourth butterfly valve is located on the other side of the interface end and is used for controlling the communication between the water diversion pipe and the recharge water pipe.

[0010] In a possible implementation, the gas lift mechanism installed in the down gas lift module step includes a gas lift pipe string, and the gas lift pipe string is fixedly arranged on the sealing cover plate and formed by a plurality of branch pipes which are sequentially flange-connected.

[0011] In a possible implementation, the gas lift mechanism further includes a support structure, and the support structure includes an annular base, an annular gravity seat, a support structure, a pipe locking structure and a traction structure; the annular base has three extension arms which are radially extended from the annular base; the annular gravity seat is located above the annular base, and the annular gravity seat has three connecting arms corresponding to the three extension arms; the support structure is provided with three support structures which are arranged corresponding to the three extension arms, and each support structure is connected with the corresponding extension arm and the corresponding connecting arm; the pipe locking structure is arranged on the annular base and detachably connected with the bottom end of the gas lift pipe string; the traction structure is located on the wellhead device and connected with the annular gravity seat, and used for pulling the annular gravity seat to move away from the annular base, so that each support structure is disengaged from the inner wall of the recharge well.

[0012] After the traction structure contacts the annular gravity seat, the annular gravity seat moves relative to the annular base by its own gravity, so that each support structure is disengaged from the inner wall of the recharge well.

[0013] In a possible implementation, each of the support structures comprises a first turnover rod, a second turnover rod, an abutting block and a connecting rod; one end of the first turnover rod is hinged to the extending end of the extending arm; the second turnover rod is hinged to the extending end of the extending arm and is arranged in parallel and spaced apart from the first turnover rod, and the second turnover rod extends towards the annular base; the other end of the first turnover rod and the other end of the second turnover rod are respectively hinged to the abutting block, so as to combine the first turnover rod, the second turnover rod and the extending arm to form a parallel four-bar linkage structure, and the parallel four-bar linkage structure is used to abut against the inner wall of the recharge well after the first turnover rod and the second turnover rod are downwardly tilted; one end of the connecting rod is hinged to the extending end of the second turnover rod, and the other end of the connecting rod is hinged to the corresponding connecting arm.

[0014] In a possible implementation, the lock pipe structure comprises a support rod and a clamp; the support rod is provided with two support rods, and the two support rods are located between any two adjacent extending arms; one end of each of the support rods is hinged to the annular base, and the two support rods are arranged at an included angle in the vertical direction; the clamp is provided with two clamps, and the two clamps are arranged in one-to-one correspondence with the two support rods; and the other end of each of the clamps is hinged to the corresponding support rod, and the two clamps are used to be fixedly sleeved on the outer wall of the gas lift pipe string.

[0015] In a possible implementation, the surface equipment installation step is provided with a backflow water treatment device, which comprises a buffer tank and a filter tank; the inlet of the buffer tank is in communication with the wellhead device; the buffer tank is provided with an exhaust valve for pressure relief; the inlet of the filter tank is in communication with the outlet of the buffer tank, and the outlet of the filter tank is in communication with other recharge wells; and the filter tank is used to filter the backflow water introduced by the buffer tank.

[0016] In a possible implementation, the filter tank comprises a tank body, a filter screen, an air nozzle and an auger; the tank body has a tank cavity, and a partition plate is arranged at the bottom of the tank cavity; the bottom end of the filter screen is connected to the top end of the partition plate, the top end of the filter screen extends upwardly and is connected to the top end of the tank cavity, and the filter screen divides the tank cavity into a water inlet cavity and a water outlet cavity; the air nozzle is provided with a plurality of air nozzles, each of the air nozzles is located in the water outlet cavity, and each of the air nozzles is arranged horizontally towards the filter screen, so as to blow compressed air into the filter screen, and each of the air nozzles is used to be in communication with an external air pump; and one end of the auger is located at the bottom of the partition plate and is in communication with the water inlet cavity, so as to discharge impurities deposited at the bottom of the partition plate.

[0017] In the filter tank, the inlet is located above the filter screen.

[0018] In the present embodiment, the gas lift mechanism is installed on the wellhead device, compressed air can be blown into the recharge well through the air compressor, the compressed air mixes with the liquid in the recharge well to form a gas-liquid mixture with smaller density, a negative pressure is formed in the well, and the blocked impurities can be carried to the wellhead device and introduced into the water lifting treatment equipment through the wellhead device, which can effectively replace the traditional submersible pump, solve the blockage, and reduce the water lifting amount. In addition, the water lifting treatment equipment can treat the water lifting, and the treated water lifting can be introduced into other recharge wells, which can solve the problem of difficult treatment of water lifting and has strong practicality. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 A flowchart of the gas lift water lifting process suitable for the middle-deep geothermal recharge well is provided for the embodiment of the present application.

[0020] Figure 2 A structural diagram of the gas lift water lifting process suitable for the middle-deep geothermal recharge well is provided for the embodiment of the present application.

[0021] Figure 3 A structural diagram of the gas lift mechanism of the gas lift water lifting process suitable for the middle-deep geothermal recharge well is provided for the embodiment of the present application.

[0022] Figure 4 A Figure 3 A top view structural diagram of the gas lift water lifting process suitable for the middle-deep geothermal recharge well is shown.

[0023] Figure 5 A cross-sectional structural diagram of the filter tank of the gas lift water lifting process suitable for the middle-deep geothermal recharge well is provided for the embodiment of the present application.

[0024] BRIEF DESCRIPTION OF DRAWINGS:

[0025] 10, wellhead device; 11, wellhead pipe; 12, sealing cover plate; 13, branch pipe; 14, elbow pipe; 15, water guide pipe;

[0026] 20, gas lift mechanism; 21, gas lift pipe string; 22, support assembly; 221, annular base; 2211, extension arm; 222, annular gravity seat; 2221, connecting arm; 223, support structure; 2231, first overturning rod; 2232, second overturning rod; 2223, abutting block; 2224, connecting rod; 224, pipe locking structure; 2241, support rod; 2242, clamp; 225, traction structure;

[0027] 30, water lifting treatment equipment; 31, buffer tank; 32, filter tank; 321, tank body; 322, filter screen; 323, air nozzle; 324, auger; 325, partition plate; 40, recharge well. DETAILED DESCRIPTION

[0028] In order to make the technical problems to be solved by the present application, technical solutions and beneficial effects clearer, the present application will be further described in detail below in combination with the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and not used to limit the present application.

[0029] Please refer to Figure 1 and Figure 2 , the gas lift and backwashing process suitable for the middle-deep geothermal recharge well provided by the present application will be described. The gas lift and backwashing process suitable for the middle-deep geothermal recharge well includes the following steps:

[0030] S100: ground equipment installation, installing the wellhead device 10 on the recharge well 40, and installing the backwashing water treatment equipment 30, connecting the wellhead device 10 with the recharge water pipe and the backwashing water treatment equipment 30 respectively, and connecting the backwashing water treatment equipment 30 with other recharge wells 40.

[0031] S200: lowering the gas lift module, installing the gas lift mechanism 20 on the wellhead device 10, so that the bottom end of the gas lift mechanism 20 extends below the aquifer, and then connecting the gas lift mechanism 20 with the air compressor.

[0032] S300: gas lift operation, starting the air compressor, and injecting compressed air into the recharge well 40 through the gas lift mechanism 20, so that the gas-liquid mixture formed in the recharge well 40 carries the blocked impurities through the wellhead device 10 into the backwashing water treatment equipment 30.

[0033] The gas lift and backwashing process suitable for the middle-deep geothermal recharge well provided by the present embodiment, compared with the prior art, installs the gas lift mechanism 20 on the wellhead device 10, can inject compressed air into the recharge well 40 through the air compressor, the compressed air mixes with the liquid in the recharge well 40 to form a gas-liquid mixture with smaller density, forms negative pressure in the well, and as the gas-liquid mixture expands and rises, can carry the blocked impurities to the wellhead device 10 and introduce them into the backwashing water treatment equipment 30 through the wellhead device 10, can effectively replace the previous submersible pump, can solve the blockage and reduce the amount of backwashing water. In addition, the backwashing water treatment equipment 30 can treat the backwashing water, and introduce the treated backwashing water into other recharge wells 40, can solve the problem that the backwashing water is difficult to treat, and has strong practicality.

[0034] In some embodiments, the wellhead device 10 described above can adopt the structure as shown in Figure 2 . Referring to Figure 2The wellhead device 10 set in the ground equipment installation step includes a wellhead pipe 11, a sealing cover plate 12, a branch pipe 13, an elbow pipe 14, and a water diversion pipe 15. The wellhead pipe 11 is fixedly installed at the top end of the recharge well 40. The sealing cover plate 12 is located at the top end of the wellhead pipe 11 and is detachably connected with the wellhead pipe 11. One end of the branch pipe 13 is fixedly connected with the wellhead pipe 11 and communicates with the lumen of the wellhead pipe 11, and the other end of the branch pipe 13 communicates with the water lifting treatment equipment 30, and the branch pipe 13 is provided with a first butterfly valve. One end of the elbow pipe 14 is fixedly connected with the wellhead pipe 11 and communicates with the lumen of the fixed pipe, and the elbow pipe 14 is provided with a second butterfly valve. The water diversion pipe 15 has two connecting ends and an interface end between the two connecting ends, the two connecting ends respectively communicate with the recharge water pipe and the water lifting treatment equipment 30, and the interface end communicates with the other end of the elbow pipe 14, and the water diversion pipe 15 is provided with a third butterfly valve and a fourth butterfly valve, the third butterfly valve is located on one side of the interface end and is used for controlling the communication between the water diversion pipe 15 and the water lifting treatment equipment 30, and the fourth butterfly valve is located on the other side of the interface end and is used for controlling the communication between the water diversion pipe 15 and the recharge water pipe.

[0035] In use, when recharge is needed, the fourth butterfly valve and the second butterfly valve are opened, and the first butterfly valve and the third butterfly valve are closed, and the recharge operation is started; when water lifting is needed, the fourth butterfly valve is closed, and the first butterfly valve, the second butterfly valve and the third butterfly valve are opened, so that the water lifting water is introduced into the water lifting treatment equipment 30.

[0036] In the embodiment, the water lifting of the water lifting water is realized by the branch pipe 13 and the elbow pipe 14, which can ensure the water lifting efficiency of the water lifting water. The structure can also avoid the position on the sealing cover plate 12 to ensure the installation of the gas lifting mechanism 20.

[0037] In some embodiments, the above-mentioned gas lifting mechanism 20 can adopt the structure as shown in Figures 2 to 3 . Referring to Figures 2 to 3 , the gas lifting mechanism 20 installed in the gas lifting module lowering step includes a gas lifting pipe string 21, the gas lifting pipe string 21 is fixedly arranged on the sealing cover plate 12, and the gas lifting pipe string 21 is formed by a plurality of branch pipes which are sequentially flange-connected.

[0038] The structure can facilitate assembly and facilitate the downward movement of the pipe.

[0039] It should be noted that the gas lifting pipe string 21 can be made of glass steel, and the length of the glass pipe string is between 800m and 1000m.

[0040] In some embodiments, the above-mentioned gas lifting mechanism 20 can adopt the structure as shown in Figures 3 to 4 . Referring to Figures 3 to 4, the gas lift mechanism 20 further comprises a support assembly 22, the support structure 223 comprises an annular base 221, an annular gravity base 222, a support structure 223, a lock pipe structure 224 and a traction structure 225. The annular base 221 has three extension arms 2211, each of which extends along the radial direction of the annular base 221. The annular gravity base 222 is located above the annular base 221, and the annular gravity base 222 has three connecting arms 2221 corresponding to the three extension arms 2211. The support structure 223 is provided with three, three support structures 223 are provided one by one with the three extension arms 2211, each support structure 223 is connected with the corresponding extension arm 2211, and is connected with the corresponding connecting arm 2221. The lock pipe structure 224 is arranged on the annular base 221 and is detachably connected to the bottom end of the gas lift pipe string 21. The traction structure 225 is located on the wellhead device 10 and is connected with the annular gravity base 222, which is used to pull the annular gravity base 222 away from the annular base 221, so that each support structure 223 abuts against the inner wall of the recharge well 40.

[0041] When the gas-liquid mixture rises, the rolling of the gas will cause the gas lift pipe string 21 to sway, because the length of the gas lift pipe string 21 is long and the weight is large, the sway of the gas lift pipe string 21 will knock against the inner wall of the recharge well 40, or will appear fatigue, and will cause the gas lift pipe string 21 to break in severe cases. Therefore, the support structure 223 is mainly arranged to fix the bottom end of the gas lift pipe string 21 to prevent the sway of the gas lift pipe string 21.

[0042] By pulling the annular gravity base 222 upward through the traction structure 225, the annular gravity base 222 will move away from the annular base 221, at this time each support structure 223 will abut against the inner wall of the recharge well 40 to fix the gas lift pipe string 21. After the traction structure 225 contacts the annular gravity base 222, the annular gravity base 222 moves relative to the annular base 221 by relying on its own gravity, so that each support structure 223 is separated from the abutment with the inner wall of the recharge well 40. This structure can effectively prevent the sway of the gas lift pipe string 21, and is also convenient to operate and has strong practicality.

[0043] In this embodiment, the traction structure 225 can include a high-strength corrosion-resistant deep-sea cable, a traction machine and a one-way lock rope device. One end of the high-strength corrosion-resistant deep-sea cable is fixedly connected with the annular gravity base 222. The traction machine is arranged outside the wellhead device 10. The one-way lock rope device is fixedly arranged in the wellhead device 10. The other end of the high-strength corrosion-resistant deep-sea cable passes through the one-way lock rope device and is connected with the traction machine outside the wellhead device 10. In addition, in order to prevent the high-strength corrosion-resistant deep-sea cable from breaking, a plurality of high-strength corrosion-resistant deep-sea cables can be arranged at the same time.

[0044] In some embodiments, the above-mentioned support structure 223 can be adopted asFigure 3 The structure shown. See also Figure 3 Each support structure 223 includes a first flipping rod 2231, a second flipping rod 2232, an abutment block 2223, and a connecting rod 2224. One end of the first flipping rod 2231 is hinged to the extended end of the extension arm 2211. The second flipping rod 2232 is hinged to the extended end of the extension arm 2211 and is spaced parallel to the first flipping rod 2231, extending towards the annular base 221. The abutment block 2223 is hinged to the other ends of the first flipping rod 2231 and the second flipping rod 2232, forming a parallel four-bar linkage 2224 structure with the first flipping rod 2231, the second flipping rod 2232, and the extension arm 2211, for abutting against the inner wall of the reinjection well 40 after the first flipping rod 2231 and the second flipping rod 2232 have rotated downwards. One end of the connecting rod 2224 is hinged to the extended end of the second flipping rod 2232, and the other end is hinged to the corresponding connecting arm 2221.

[0045] The parallel four-bar linkage 2224 structure ensures that the contact surface on the contact block 2223 is always set in the vertical direction, thereby ensuring stable and limited contact with the inner wall of the reinjection well 40. Preferably, a shock-absorbing and wear-resistant pad can be provided on the outer wall of the contact block 2223.

[0046] In some embodiments, the locking tube structure 224 described above can be adopted as follows: Figure 3 The structure shown. See also Figure 3 The locking tube structure 224 includes support rods 2241 and clamps 2242. Two support rods 2241 are provided, located between any two adjacent extension arms 2211. One end of each support rod 2241 is hinged to the annular base 221, and the two support rods 2241 are arranged at an angle in the vertical direction. Two clamps 2242 are provided, corresponding one-to-one with the two support rods 2241, and each clamp 2242 is hinged to the other end of the corresponding support rod 2241. The two clamps 2242 are used to fix the tubes onto the outer wall of the air lift tube string 21.

[0047] Because the gas lift pipe string 21 is not coaxial with the sealing cover plate 12 or the wellhead pipe 11, in order to ensure that the support structure 223 can act on the gas lift pipe string 21, the two support rods 2241 can be flipped in opposite directions to form a triangular frame, and are connected to the gas lift pipe string 21 through two clamps 2242. This structure can adjust the axial distance between the annular base 221 and the gas lift pipe string 21 to adapt to the axial distance between the gas lift pipe string 21 and the reinjection well 40, with high stability and good adaptability.

[0048] In addition, it should be noted that both the annular base 221 and the annular gravity seat 222 are coaxially arranged with the recharge well 40.

[0049] In some embodiments, the aforementioned return water treatment device 30 may employ, as follows: Figure 1 The structure shown. See also Figure 1 The return water treatment equipment 30 installed during the ground equipment installation process includes a buffer tank 31 and a filter tank 32. The inlet of the buffer tank 31 is connected to the wellhead device 10. The buffer tank 31 is equipped with an air release valve for pressure relief. The inlet of the filter tank 32 is connected to the outlet of the buffer tank 31, and the outlet of the filter tank 32 is connected to other reinjection wells 40. The filter tank 32 is used to filter the return water introduced by the buffer tank 31. The buffer tank 31 can discharge gas from the return water and buffer the flow rate of the return water. The filter tank 32 ensures that the return water is filtered so that it can be introduced into other reinjection wells 40.

[0050] In some embodiments, the filter tank 32 body may be adopted as follows: Figure 5 The structure shown. See also Figure 5 The filter tank 32 includes a tank body 321, a filter screen 322, air nozzles 323, and an auger 324. The tank body 321 has a tank cavity, with a partition plate 325 at the bottom. The bottom end of the filter screen 322 is connected to the top end of the partition plate 325, and the top end of the filter screen 322 extends obliquely upwards and connects to the top end of the tank cavity, dividing the tank cavity into an inlet cavity and an outlet cavity. Multiple air nozzles 323 are provided, each located in the outlet cavity, and each air nozzle 323 is horizontally positioned towards the filter screen 322, used to blow compressed air into the filter screen 322. Each air nozzle 323 is connected to an external air pump. One end of the auger 324 is located at the bottom of the partition plate 325 and communicates with the inlet cavity, used to discharge impurities deposited at the bottom of the partition plate 325.

[0051] The inlet on the filter tank 32 is located above the filter screen 322.

[0052] The compressed air blown by the air nozzle 323 can clean the impurities on the filter screen 322 to prevent the filter screen 322 from clogging. At the same time, it can give the impurities a push so that the impurities enter the other side of the partition plate 325 and deposit at the bottom of the partition plate 325. It can be carried out by the screw conveyor 324 in a timely manner, with high processing efficiency, good filtration effect and strong practicality.

[0053] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A gas lift reinjection process suitable for use in a medium-deep geothermal reinjection well, characterized in that, The method comprises the following steps: ground equipment installation, installing wellhead device on recharge well, and installing recharge water treatment equipment, the wellhead device is communicated with recharge water pipe and the recharge water treatment equipment respectively, and the recharge water treatment equipment is communicated with other recharge wells; the wellhead device comprises wellhead pipe, sealing cover plate, branch pipe, elbow pipe and water inlet pipe; lowering gas lift module, installing gas lift mechanism on the wellhead device, extending the bottom end of the gas lift mechanism to the aquifer, and connecting the gas lift mechanism with air compressor; the gas lift mechanism comprises gas lift pipe string; the gas lift mechanism further comprises a support assembly, the support assembly comprises an annular base, an annular gravity seat, a support structure, a pipe locking structure and a traction structure; the annular base has three extension arms, which extend radially from the annular base; the annular gravity seat is located above the annular base, and the annular gravity seat has three connection arms corresponding to the three extension arms; the support structure is provided with three, the three support structures are provided one by one corresponding to the three extension arms, each support structure is connected with the corresponding extension arm and the corresponding connection arm; the pipe locking structure is arranged on the annular base and is detachably connected to the bottom end of the gas lift pipe string; the traction structure is located on the wellhead device and is connected with the annular gravity seat, which is used to pull the annular gravity seat away from the annular base to make the support structures abut against the inner wall of the recharge well; after the traction structure releases the traction on the annular gravity seat, the annular gravity seat moves relative to the annular base by its own gravity to make the support structures separate from the inner wall of the recharge well; each support structure comprises a first flip lever, a second flip lever, an abutting block and a connecting rod; one end of the first flip lever is hinged to the extension end of the extension arm; the second flip lever is hinged to the extension end of the extension arm and is arranged in parallel and spaced apart from the first flip lever, and the second flip lever extends towards the annular base; the abutting block is hinged to the other end of the first flip lever and the second flip lever to form a parallel four-bar linkage structure with the first flip lever, the second flip lever and the extension arm, which is used to abut against the inner wall of the recharge well after the first flip lever and the second flip lever are downwardly pitched; one end of the connecting rod is hinged to the extension end of the second flip lever, and the other end is hinged to the corresponding connection arm; gas lift operation, starting the air compressor, injecting compressed air into the recharge well through the gas lift mechanism, and making the gas-liquid mixture formed in the recharge well carry the blocked impurities through the wellhead device into the recharge water treatment equipment.

2. The gas lift swabbing process suitable for use in a medium-depth geothermal reinjection well according to claim 1, characterized in that, The wellhead pipe is fixedly installed at the top end of the recharge well; the sealing cover plate is located at the top end of the wellhead pipe and detachably connected with the wellhead pipe; one end of the branch pipe is fixedly connected with the wellhead pipe and communicates with the lumen of the wellhead pipe, and the other end of the branch pipe communicates with the backwashing water treatment equipment; one end of the elbow pipe is fixedly connected with the wellhead pipe and communicates with the lumen of the wellhead pipe, and the elbow pipe is provided with a second butterfly valve; the water guide pipe has two connecting ends, and an interface end is arranged between the two connecting ends; the two connecting ends respectively communicate with the recharge water pipe and the backwashing water treatment equipment; the interface end communicates with the other end of the elbow pipe; the water guide pipe is provided with a third butterfly valve and a fourth butterfly valve; the third butterfly valve is located on one side of the interface end and is used for controlling the communication between the water guide pipe and the backwashing water treatment equipment; and the fourth butterfly valve is located on the other side of the interface end and is used for controlling the communication between the water guide pipe and the recharge water pipe.

3. The gas lift swabbing process suitable for use in a medium-depth geothermal reinjection well according to claim 2, characterized in that, The gas lift pipe string is fixedly arranged on the sealing cover plate, and the gas lift pipe string is formed by a plurality of branch pipes which are sequentially flange-connected.

4. The gas lift swabbing process suitable for use in a medium-depth geothermal reinjection well according to claim 1, characterized in that, The lock pipe structure comprises a support rod and a clamp; the support rod is provided with two, and the two support rods are located between any two adjacent extension arms; one end of each support rod is hingedly connected with the annular base, and the two support rods are arranged at an included angle in the vertical direction; the clamp is provided with two, and the two clamps are arranged in one-to-one correspondence with the two support rods, and the other end of each clamp is hingedly connected with the corresponding support rod; and the two clamps are used for being fixedly sleeved on the outer wall of the gas lift pipe string.

5. The gas lift swabbing process suitable for use in a medium-depth geothermal reinjection well according to claim 1, characterized in that, The backwashing water treatment equipment provided in the ground equipment installation step comprises a buffer tank and a filter tank; the inlet of the buffer tank communicates with the wellhead device; the buffer tank is provided with an exhaust valve for pressure relief; the inlet of the filter tank communicates with the outlet of the buffer tank, and the outlet of the filter tank communicates with other recharge wells; and the filter tank is used for filtering the backwashing water introduced from the buffer tank.

6. The gas lift swabbing process suitable for use in a medium-depth geothermal reinjection well according to claim 5, characterized in that, The filter tank comprises a tank body, a filter screen, an air nozzle and an auger; the tank body has a tank cavity, and a partition plate is arranged at the bottom of the tank cavity; the bottom end of the filter screen is connected with the top end of the partition plate, the top end of the filter screen extends upwardly and is connected with the top end of the tank cavity, and the filter screen divides the tank cavity into a water inlet cavity and a water outlet cavity; a plurality of air nozzles are arranged in the water outlet cavity, and each air nozzle is arranged horizontally towards the filter screen and is used for blowing compressed air into the filter screen; and each air nozzle is used for communicating with an external air pump; one end of the auger is located at the bottom of the partition plate and communicates with the water inlet cavity, and is used for discharging impurities deposited at the bottom of the partition plate. The inlet of the filter tank is located above the filter screen.

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