Well wall descaling and derusting device and method

Abstract

The invention belongs to the technical field of well wall maintenance, and particularly relates to a well wall descaling and derusting device and method. The well wall descaling and derusting device comprises a hollow pipe; the ultrasonic thickness gauge is arranged on the hollow pipe; the spraying mechanism is arranged at the lower end part of the hollow pipe and is connected with a chemical scale remover barrel and a chemical rust remover barrel; the plugging bridge plug is arranged at the lower end part of the injection mechanism, and the plugging bridge plug is constructed to be capable of repeatedly plugging the well wall; and a data analysis module, wherein the ultrasonic thickness gauge, the injection mechanism and the plugging bridge plug are electrically connected with the data analysis module.

Description

Technical Field

[0001] The present invention belongs to the technical field of well wall maintenance, and in particular relates to a well wall descaling and rust removal device and a well wall descaling and rust removal method. Background Art

[0002] During geothermal energy extraction, the pressure of geothermal fluid rapidly decreases as it rises near the wellhead, causing flash evaporation. This causes CaCO3 in the fluid to precipitate, which then adheres to the wellbore walls, forming calcium scale. This large amount of calcium scale adheres to the wellbore surface, reducing the diameter of the production wellbore. This not only lowers the temperature and flow rate of the high-temperature water, but can also lead to blockage or even failure of the production well. Furthermore, the excessive presence of heavy metal ions in geothermal water can severely corrode or even penetrate the metal wellbore walls, which normally last for more than 20 years, within just two to three years, causing water loss and reduced production.

[0003] Conventional methods for removing calcium scale from well walls currently involve injecting chemicals into production wells or using physical methods. Because calcium scale forms far from the surface, mechanical descaling is inefficient at deep locations. Furthermore, scale removed from the well walls can continue to settle downward, potentially blocking sections of the well. Furthermore, chemical injection for descaling results in uncontrolled chemical distribution, resulting in poor application uniformity.

[0004] Therefore, it is extremely urgent to find a device and method that can quickly complete the descaling and rust removal operation of geothermal wells. Summary of the Invention

[0005] In view of the technical problems mentioned above, the present invention aims to provide a well wall descaling and rust removal device, which can complete the work of descaling and rusting the well wall.

[0006] The present invention also proposes a method for removing scale and rust from the well wall, which can complete the work of removing scale and rust from the well wall.

[0007] According to the present invention, a device for removing scale and rust from a well wall is provided, comprising:

[0008] hollow tube;

[0009] an ultrasonic thickness gauge disposed on the hollow tube;

[0010] An injection mechanism is provided at the lower end of the hollow tube, and the injection mechanism is connected to the chemical descaling agent barrel and the chemical rust remover barrel;

[0011] A blocking bridge plug provided at the lower end of the injection mechanism, wherein the blocking bridge plug is configured to repeatedly block the well wall; and

[0012] A data analysis module is provided, wherein the ultrasonic thickness gauge, the injection mechanism and the blocking bridge plug are all electrically connected to the data analysis module.

[0013] In a specific embodiment, the injection mechanism includes:

[0014] a liquid cylinder, wherein a liquid discharge valve is provided in the liquid cylinder;

[0015] A piston cylinder, wherein the piston cylinder is movably sealed and disposed in the liquid cylinder, and a liquid inlet valve is disposed in the piston cylinder, with both ends of the liquid inlet valve being connected to the inner cavity of the piston cylinder and the inner cavity of the liquid cylinder respectively; and

[0016] The nozzle, the two ends of the liquid discharge valve are respectively connected to the inner cavity of the liquid cylinder and the nozzle;

[0017] Wherein, the liquid discharge valve and the liquid inlet valve are both configured to only allow the fluid to flow in one direction from the piston cylinder to the nozzle.

[0018] In a specific embodiment, the liquid inlet valve includes a first sealing member sealed in the cavity of the piston cylinder, a first flow hole is axially penetrated through the first sealing member, a second flow hole connected to the inner cavity of the liquid cylinder is provided at the lower end of the piston cylinder, a first spring is provided between the first sealing member and the lower end of the piston cylinder, and a first sealing block is provided at the upper end of the first spring to seal the first flow hole.

[0019] In a specific embodiment, the drain valve includes a second sealing member sealed in the cavity of the liquid cylinder, a third flow hole is axially penetrated on the second sealing member, a fourth flow hole connected to the inner cavity of the nozzle is provided at the lower end of the liquid cylinder, a second spring is provided between the second sealing member and the lower end of the liquid cylinder, and a second sealing block is provided at the upper end of the second spring to block the third flow hole.

[0020] In a specific embodiment, the injection mechanism further includes a connecting sleeve, the liquid cylinder is fixedly connected to the connecting sleeve, an upper joint is connected to the upper end of the piston cylinder, and the connecting sleeve is axially movable and limitedly connected to the upper joint.

[0021] In a specific embodiment, the blocking bridge plug includes:

[0022] Bridge plug rod;

[0023] A plurality of sealing support rods are evenly arranged on the bridge plug rod along the circumferential direction, one end of each sealing support rod is hinged to the bridge plug rod, and the other end is used for sealing with the well wall.

[0024] In a specific embodiment, a sliding sleeve is movably provided on the bridge plug rod along the axial direction, and a folding support rod is hinged between the sliding sleeve and each of the sealing support rods.

[0025] In a specific embodiment, an electromagnetic connection shaft is provided at the upper end of the bridge plug rod, and the sliding sleeve is configured to move up and down along the bridge plug rod in response to the electromagnetic force of the electromagnetic connection shaft.

[0026] According to the present invention, a method for removing scale and rust from a well wall is also proposed, comprising the following steps:

[0027] The well wall descaling and rust removal device according to the present invention is lowered into the well to a predetermined depth through a drill rod, and the top of the drill rod is connected to a drilling rig;

[0028] The drilling rig drives the well wall descaling and rust removal device to rotate and rise through the drill pipe. At the same time, the ultrasonic thickness gauge measures the well wall to determine whether descaling or rust removal is needed.

[0029] When removing scale or rust, the blocking bridge plug seals the wellbore and the injection mechanism sprays chemical reagents onto the well wall.

[0030] In a specific embodiment, when descaling or rust removal is completed, the spraying mechanism sprays cleaning water onto the well wall for cleaning.

[0031] Compared with the prior art, the advantages of this application are:

[0032] The present invention can achieve both scale removal and rust removal by running the pipe string into and raising it in one trip, and has the function of collecting quality data of the inner wall of the production casing, thereby extending the service life of the geothermal well pipe. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The present invention will be described below with reference to the accompanying drawings.

[0034] Figure 1 A schematic diagram showing an embodiment of a well wall descaling and rust removal device according to the present invention;

[0035] Figure 2 A schematic diagram showing an embodiment of an injection mechanism according to the present invention is shown;

[0036] Figure 3 A schematic diagram showing an embodiment of a bridge plug according to the present invention is shown;

[0037] Figure 4 A schematic diagram showing the shrinkage of the occluding bridge plug according to the present invention is shown;

[0038] Figure 5 A schematic diagram showing the deployment of the blocking bridge plug according to the present invention is shown.

[0039] In the picture:

[0040] 1. Well wall; 2. Hollow tube; 3. Ultrasonic thickness gauge; 4. Injection mechanism; 400. Effective cavity; 401. Upper joint; 402. Connecting sleeve; 403. Piston cylinder; 404. Return spring; 405. First sealing ring; 406. Liquid inlet valve; 407. Liquid cylinder; 408. Liquid discharge valve; 409. Fixed sleeve; 410. Nozzle; 411. Liquid injection port; 40. Second flow hole; 41. First sealing member; 42. First flow hole; 43. First spring; 44. First sealing block; 45. Fourth flow hole; 46. Second sealing member; 47. Third flow hole Flow hole; 48. Second spring; 49. Second sealing block; 5. Electromagnetic connecting shaft; 6. Blocking bridge plug; 601. Bridge plug rod; 602. Sleeve; 603. Folding support rod; 604. Connecting keyway; 605. Sealing support rod; 606. Guide; 607. Support plate; 608. Skirt seal; 7. Corrosion pit; 8. Scale; 9. Power supply device; 10. Data analysis module; 11. Control module; 12. Cleaning bucket; 13. Chemical descaling agent barrel; 14. Chemical rust remover barrel; 18. Limiting groove; 19. Limiting piece; 100. Well wall descaling and rust removal device.

[0041] In this application, all drawings are schematic drawings, which are only used to illustrate the principles of the present invention and are not drawn to scale. DETAILED DESCRIPTION

[0042] The present invention will be described below with reference to the accompanying drawings.

[0043] It should be noted that, in this application, the direction close to the wellhead after the well wall descaling and rust removal device according to the present invention is put into the well is described as "upper end", "front end" or similar terms, that is, Figure 1 The direction away from the wellhead after the well wall descaling and rust removal device according to the present invention is described as the "lower end", "rear end" or similar terms, that is, Figure 1 Below.

[0044] Figure 1 This is a schematic diagram of a well wall descaling and rust removal device 100 for treating a geothermal well in this embodiment. Figure 1 The well wall 1 in the figure is the inner wall of the geothermal well (specifically the inner wall of the production casing of the geothermal well). It is easy to understand that the present invention is not limited to geothermal wells, and can also be used in other wells in the field.

[0045] Figure 1 The structure of the well wall descaling and rust removal device 100 according to the present invention is shown. Figure 1 As shown, the well wall descaling and rust removal device 100 includes a hollow tube 2, an ultrasonic thickness gauge 3, a jetting mechanism 4 and a blocking bridge plug 6.

[0046] The hollow tube 2 is configured as a cylindrical tube, that is, fluid can enter the hollow tube 2 from one end thereof and flow out from the other end thereof. In a specific embodiment, the hollow tube 2 can be replaced by a hollow drill rod.

[0047] Spray mechanism 4 is coaxially fixedly disposed below hollow tube 2 and communicates with hollow tube 2. Spray mechanism 4 is connected to chemical descaling agent barrel 13 and chemical rust remover barrel 14 placed on the ground via hollow tube 2. Fluid within chemical descaling agent barrel 13 and chemical rust remover barrel 14 can enter hollow tube 2 and enter spray mechanism 4 along hollow tube 2. Spray mechanism 4 can spray the fluid toward well wall 1. An ultrasonic thickness gauge 3 is fixedly disposed on the outer wall of hollow tube 2 and disposed above spray mechanism 4. Ultrasonic thickness gauge 3 is well known to those skilled in the art and can measure the thickness of well wall 1. The measurement results of ultrasonic thickness gauge 3 can be used to determine whether scale or rust has formed on well wall 1. The blocking bridge plug 6 is coaxially fixedly arranged at the lower end of the injection mechanism 4. The blocking bridge plug 6 is configured to repeatedly block the well wall 1. Specifically, when the injection mechanism 4 sprays fluid onto the well wall 1, the blocking bridge plug 6 radially expands and is in sealing contact with the well wall 1. When the well wall descaling and rust removal device 100 needs to be moved, the blocking bridge plug 6 radially contracts and separates from the well wall 1.

[0048] According to the present invention, in a preferred embodiment, the wellbore descaling and rust removal device 100 further includes a data analysis module 10, and the ultrasonic thickness gauge 3, the injection mechanism 4, and the plugging bridge plug 6 are all electrically connected to the data analysis module 10. Furthermore, the wellbore descaling and rust removal device 100 further includes a control module 11, which is used to control the data analysis module 10, the ultrasonic thickness gauge 3, the injection mechanism 4, the plugging bridge plug 6, and the like to perform actions.

[0049] It is easy to understand that the specific structures of the data analysis module 10 and the control module 11 are well known to those skilled in the art and will not be described in detail here.

[0050] According to the present invention, Figure 2 As shown, in a specific embodiment, the spraying mechanism 4 includes a liquid cylinder 407 , a piston tube 403 and a nozzle 410 .

[0051] Cylinder 407 is constructed in a roughly cylindrical shape, with an open top and a fourth flow hole 45 at its bottom, connecting the interior of cylinder 407 to the outside. A drain valve 408 is coaxially and sealed within cylinder 407. This valve is designed to allow only one-way flow of fluid from top to bottom. In other words, the fluid within cylinder 407 can only flow from top to bottom under the action of drain valve 408.

[0052] The piston cylinder 403 is constructed in a generally cylindrical shape. Its upper end is open, and its lower end is provided with a second flow hole 40, which connects the interior of the piston cylinder 403 with the exterior. A fluid inlet valve 406 is coaxially and sealed within the piston cylinder 403. This valve is configured to allow only one-way flow of fluid from top to bottom. In other words, fluid within the piston cylinder 403 can only flow from top to bottom under the action of the fluid inlet valve 406.

[0053] Overall, the structure formed by piston cylinder 403 and inlet valve 406 is similar to that formed by liquid cylinder 407 and discharge valve 408. Piston cylinder 403 is smaller than liquid cylinder 407 and is coaxially movable within liquid cylinder 407. A first sealing ring 405 is positioned between the outer wall of piston cylinder 403 and the inner wall of liquid cylinder 407. The upper end of piston cylinder 403 is connected to upper connector 401, which is in communication with hollow tube 2. This allows fluid to flow through hollow tube 2 and into the inner cavity of piston cylinder 403.

[0054] The injection mechanism 4 operates as follows: the piston cylinder 403 reciprocates up and down relative to the fluid cylinder 407. For ease of explanation, the present invention designates the space formed between the piston cylinder 403 and the fluid cylinder 407 as the effective cavity 400. As the piston cylinder 403 moves upward relative to the fluid cylinder 407, the volume of the effective cavity 400 increases, generating negative pressure. The inlet valve 406 and the outlet valve 408 are located at the upper and lower sides of the effective cavity 400, respectively. These valves only allow fluid to flow from top to bottom. Therefore, the fluid in the piston cylinder 403 enters the effective cavity 400 through the inlet valve 406 and the second flow hole 40. When the piston tube 403 moves downward relative to the liquid cylinder 407, the volume of the effective cavity 400 decreases and the internal pressure increases. The liquid inlet valve 406 and the liquid discharge valve 408 are respectively located on the upper and lower sides of the effective cavity 400, and the liquid inlet valve 406 and the liquid discharge valve 408 only allow the fluid to flow from top to bottom. Therefore, the fluid in the effective cavity 400 will be discharged downward through the fourth flow hole 45 through the liquid discharge valve 408.

[0055] Nozzle 410 is constructed with a T-shaped cross-section. In practice, nozzle 410 comprises two cylindrical sections of different diameters, resulting in a T-shaped cross-section. Multiple spray ports 411 are evenly distributed along the circumference of the side of nozzle 410. The upper end of drain valve 408 communicates with active cavity 400, while the lower end of drain valve 408 communicates with nozzle 410, allowing fluid to ultimately be ejected from spray ports 411 of nozzle 410 toward well wall 1.

[0056] According to the present invention, the liquid inlet valve 406 includes a first sealing member 41 that is sealed in the cavity of the piston cylinder 403. A first flow hole 42 is axially provided on the first sealing member 41, that is, the first flow hole 42 connects the upper and lower sides of the first sealing member 41. A second flow hole 40 is axially provided at the lower end of the piston cylinder 403, and the second flow hole 40 connects the inner cavity of the piston cylinder 403 with the inner cavity of the liquid cylinder 407. A first spring 43 is coaxially provided between the first sealing member 41 and the lower end of the piston cylinder 403, and a first sealing block 44 is provided at the upper end of the first spring 43 to block the first flow hole 42. Under this arrangement, when the fluid flows from top to bottom, the fluid will push the first sealing block 44 to move downward and compress the spring, thereby opening the first flow hole 42 and allowing the fluid to pass smoothly. When the fluid flows from bottom to top, the first sealing block 44 fits more tightly against the first sealing member 41 and the first sealing block 44 cannot move upward, so that the first flow hole 42 is always in a sealed state and the fluid cannot pass through.

[0057] The structure of drain valve 408 is similar to that of inlet valve 406. It includes a second sealing member 46 sealed within the cavity of liquid cylinder 407. A third flow hole 47 is axially provided through second sealing member 46, connecting the upper and lower sides of second sealing member 46. A fourth flow hole 45 is axially provided through the lower end of liquid cylinder 407, connecting nozzle 410 with the inner cavity of liquid cylinder 407. A second spring 48 is axially provided between second sealing member 46 and the lower end of liquid cylinder 407. A second sealing block 49 is located at the upper end of second spring 48, blocking third flow hole 47.

[0058] In one embodiment, the second sealing member 46 of the drain valve 408 is configured in a cylindrical shape. Figure 2 As shown, the third flow hole 47 connects the upper space of the second spacer 46 (i.e., the effective cavity 400) with the inner cavity of the second spacer 46, and the fourth flow hole 45 connects the inner cavity of the second spacer 46 with the nozzle 410. The second spring 48 and the second sealing block 49 are both located in the inner cavity of the cylindrical barrel formed by the second spacer 46. The second sealing block 49 is located at the upper end of the second spring 48. Under the action of the second spring 48, the second sealing block 49 seals against the third flow hole 47.

[0059] According to the present invention, the shapes of the first sealing block 44 and the second sealing block 49 are not limited and can be spherical, conical or other shapes as long as they can seal the second flow hole 40 and the fourth flow hole 45 .

[0060] According to the present invention, the spray mechanism 4 also includes a connecting sleeve 402, which is configured in a generally cylindrical shape. A fixing sleeve 409 is fixedly disposed at the lower end of the connecting sleeve 402. The nozzle 410 is fixedly disposed thereto via the fixing sleeve 409. The lower portion of the fixing sleeve 409 is fixedly connected to the blocking bridge plug 6 via an electromagnetic connecting shaft 5. The upper joint 401, piston cylinder 403, and hydraulic cylinder 407 are all coaxially disposed within the connecting sleeve 402. The outer diameters of the upper joint 401 and hydraulic cylinder 407 are both larger than those of the piston cylinder 403. A return spring 404 is disposed between the upper joint 401 and hydraulic cylinder 407. Specifically, the return spring 404 is sleeved around the outer side of the piston cylinder 403, with its upper and lower ends axially abutting the upper joint 401 and hydraulic cylinder 407, respectively. Furthermore, the hydraulic cylinder 407 is fixedly connected to the connecting sleeve 402, and the upper joint 401 and piston cylinder 403 are axially movable within the connecting sleeve 402.

[0061] During operation, the blocking bridge plug 6 is set and fixed relative to the wellbore 1, thereby securing the connecting sleeve 402, which is fixedly connected to the top of the blocking bridge plug 6 via the fixing sleeve 409, relative to the wellbore 1. The upper portion of the hollow tube 2 is connected to the drill pipe. Driven by the drill pipe, the hollow tube 2 vibrates axially relative to the wellbore 1, performing axial reciprocating motion. The hollow tube 2, through the upper joint 401, drives the piston cylinder 403 to perform axial reciprocating motion relative to the hydraulic cylinder 407. During the axial reciprocating motion of the piston cylinder 403 relative to the hydraulic cylinder 407, when the preload force of the return spring 404 is exceeded, the return spring 404 is compressed, the piston cylinder 403 descends, the inlet valve 406 closes, and the fluid within the effective chamber 400 is compressed. When the pressure of the fluid within the effective chamber 400 exceeds a certain value, the drain valve 408 opens, and the pressurized fluid is ejected through the high-pressure flow channel and the high-pressure nozzle 410, dispensing a high-speed chemical descaling and rust remover. Influenced by the vibration of the drill string hollow tube 2 and the compression of the return spring 404, the upper joint 401 drives the piston cylinder 403 upward, reducing the pressure in the effective cavity 400. The drain valve 408 closes, and the inlet valve 406 opens under the pressure of the liquid flow in the drill string hollow tube 2, allowing the liquid flow to enter the effective cavity 400. Due to the vibration of the drill string and the action of the return spring 404, the piston cylinder 403 reciprocates up and down relative to the cylinder 407, generating a pressurized jet that assists in descaling and rust removal.

[0062] According to the present invention, the connecting sleeve 402 is connected to the upper joint 401 in an axially movable and limited manner. Specifically, a limiting mechanism is provided between the upper joint 401 and the connecting sleeve 402 to prevent the upper joint 401 from being separated from the connecting sleeve 402. In one embodiment, the limiting mechanism includes a limiting groove 18 and a limiting member 19. The limiting groove 18 is provided on the outer wall of the upper joint 401, and the limiting member 19 is provided on the inner wall of the connecting sleeve 402. The limiting member 19 is axially movable in the limiting groove 18. The limiting member 19 can only move within the length range of the limiting groove 18, thereby preventing the upper joint 401 from being separated from the connecting sleeve 402. According to the present invention, in a specific embodiment, as Figure 3 As shown, the blocking bridge plug 6 includes a bridge plug rod 601 and a sealing support rod 605 .

[0063] like Figures 3 to 5 As shown, multiple sealing rods 605 are evenly distributed on the bridge plug rod 601 along the circumferential direction, and the end of each sealing rod 605 is hinged to the lower end of the bridge plug rod 601, and the other end of each sealing rod 605 is used to seal with the well wall 1.

[0064] Furthermore, two adjacent sealing rods 605 are connected by a plurality of mutually hinged support plates 607. Figure 5 As shown, Figure 5 Only the structure of the support plates 607 between one group of adjacent sealing rods 605 is shown. In this embodiment, the support plates 607 are constructed to be roughly fan-shaped, with two support plates 607 provided between two adjacent sealing rods 605. The sides of the two support plates 607 are hinged to the corresponding sealing rods 605, so that the support plates 607 can rotate around the axis of the sealing rods 605. The sides of the two support plates 607 away from the sealing rods 605 are hinged to each other, and the hinge axis between the two support plates 607 is parallel to the sides of the support plates 607. The support plates 607 can be expanded or folded and contracted under the drive of the sealing rods 605. Figure 5 As shown, after the support plate 607 is unfolded, its radial dimension increases and it seals against the well wall 1, forming a sealing surface, thereby sealing the well wall 1. Figure 4 As shown, after the support plate 607 is folded and contracted, its radial dimension is reduced, thereby separating from the well wall 1.

[0065] A skirt seal 608 for sealing is provided on the skirt of each sealing support rod 605 and support plate 607. After being unfolded, the radial dimensions of the sealing support rod 605 and support plate 607 increase, and the skirt seal 608 is compressed against the well wall 1, thereby ensuring the sealing effect and also playing a fixing role to prevent the blocking bridge plug 6 from moving relative to the well wall 1.

[0066] In a preferred embodiment, the angle between the two sides of the support plate 607 can be constructed as an arc shape to better fit the circle.

[0067] Furthermore, an umbrella surface made of flexible material is provided on the inner side of each sealing support rod 605. The umbrella surface is provided on the upper side of the support plate 607 and can completely cover the support plate 607. The skirt of the umbrella surface is connected to the skirt seal to form a sealing surface, thereby preventing the fluid from contacting the support plate 607 and the sealing support rod 605, improving the sealing performance while preventing the support plate 607 and the sealing support rod 605 from being corroded.

[0068] According to the present invention, a sliding sleeve 602 is axially movable on the bridge plug rod 601. A folding support rod 603 is hinged between the sliding sleeve 602 and each sealing support rod 605. Furthermore, each sealing support rod 605 is provided with a connecting keyway 604. One end of the folding support rod 603 is hinged to the sliding sleeve 602, and the other end is hinged to the connecting keyway 604. With this arrangement, the upward and downward movement of the sliding sleeve 602 drives the movement of each sealing support rod 605 via the folding support rod 603, thereby controlling the radial expansion or contraction of the blocking bridge plug 6. When the sliding sleeve 602 moves downward relative to the bridge plug rod 601, the blocking bridge plug 6 expands radially, and the edge of the blocking bridge plug 6 seals against the well wall 1, completing the blockage of the geothermal well. When the sliding sleeve 602 moves upward relative to the bridge plug rod 601, the blocking bridge plug 6 contracts radially, and the edge of the blocking bridge plug 6 disengages from the well wall 1, releasing the blockage of the geothermal well.

[0069] According to the present invention, an electromagnetic coupling shaft 5 is disposed at the upper end of the bridge plug rod 601. The upper end of the electromagnetic coupling shaft 5 is connected to the lower end of the nozzle 410 of the injection mechanism 4. The sliding sleeve 602 is configured to move up and down along the bridge plug rod 601 in response to the electromagnetic force of the electromagnetic coupling shaft 5. When the electromagnetic coupling shaft 5 is energized, it exerts an attractive force on the sliding sleeve 602, causing it to move upward relative to the bridge plug rod 601. When the electromagnetic coupling shaft 5 is de-energized, the sliding sleeve 602 moves downward relative to the bridge plug rod 601 under the action of gravity.

[0070] It is easy to understand that the electromagnetic connection shaft 5 is a device for converting electrical energy into magnetic energy, which is well known to those skilled in the art and will not be described in detail here.

[0071] In one embodiment of the present invention, a method for removing scale and rust from a well wall is provided, comprising the following steps.

[0072] The well wall descaling and rust removal device 100 is lowered into the well to a predetermined depth through a drill pipe, and the top of the drill pipe is connected to a drilling rig.

[0073] While the drilling rig drives the well wall descaling and rust removal device 100 to rotate and rise through the drill pipe, the ultrasonic thickness gauge 3 measures the thickness of the well wall 1 to determine whether descaling or rust removal is required.

[0074] During descaling or rust removal, the blocking bridge plug 6 blocks the geothermal well, and the injection mechanism 4 injects chemical reagents toward the well wall.

[0075] In a preferred embodiment, a cleaning bucket 12 is provided on the ground, and the spray mechanism 4 is connected to the cleaning bucket 12 via a hollow tube 2. When descaling or rust removal is completed, the spray mechanism sprays cleaning water toward the well wall for cleaning. In this embodiment, the cleaning bucket 12 stores geothermal water tail water.

[0076] According to the present invention, in a specific embodiment, the steps of the well wall descaling and rust removal method are as follows:

[0077] First, the geothermal well stops production, and the well wall scale and rust removal device 100 is moved into the geothermal well through multiple hollow drill rods under the support of a drilling rig. The number of hollow drill rods is set according to actual needs until the well wall scale and rust removal device 100 moves to a predetermined position (usually the deepest position of scaling in the geothermal well, about 100m from the wellhead).

[0078] Chemical descaling agents and chemical rust removing agents are prepared in advance on the ground and are respectively loaded into the chemical descaling agent barrel 13 and the chemical rust removing agent barrel 14 , while the geothermal water tail water is loaded into the cleaning water barrel 12 .

[0079] The drilling rig drives the chemical descaling agent barrel 13 upward through the hollow drill pipe. The ultrasonic thickness gauge 3 measures the wall thickness of the geothermal well's production casing at all times and uploads the data to the surface data analysis module 10. Once a change in the geothermal well's production casing thickness is detected, if it indicates an increase, the surface chemical descaling agent channel is opened. The chemical descaling agent passes through the hollow drill pipe and is precisely sprayed onto the inner wall of the production casing by the spray mechanism 4. The change in wall thickness is proportional to the spraying time of the chemical descaling agent, and the scale layer is disintegrated by the combined effects of the chemical descaling agent and water pressure.

[0080] At the same time, an ultrasonic thickness gauge measures the minimum remaining wall thickness of the production casing after corrosion. When corrosion is detected, the surface chemical derusting agent channel is activated. The chemical passes through the hollow drill pipe and, through a hydraulically pressurized spray nozzle, is precisely sprayed onto the inner wall of the production casing, removing rust and extending its life. Data such as the size of the corrosion pit 7 and its position from the surface are uploaded to the surface data analysis module 10 to facilitate subsequent evaluation of the remaining life of the production casing.

[0081] When the injection mechanism 4 is working, the blocking bridge plug 6 expands radially and seals against the inner wall of the production tubing string, preventing scale or rust from sinking to the bottom of the well and causing wellbore blockage.

[0082] After chemical descaling or rust removal is completed, the tail water of the geothermal well is sprayed onto the inner wall of the production casing through the hollow drill pipe and the injection mechanism to prevent the chemical descaling agent or chemical rust remover from staying on the inner wall of the production casing for a long time and reduce casing corrosion.

[0083] Then, the injection mechanism is closed, and the surface water pump is started to pump the geothermal water with scale or rust residue on the blocking bridge plug 6 back to the well, and the scale and rust residue are filtered.

[0084] Then, the water pump is turned off, the blocking bridge plug 6 is radially contracted, the well wall descaling and rust removal device 100 is lifted up, and the ultrasonic thickness gauge 3 continues to work.

[0085] Finally, the drilling rig lifts the well wall descaling and rust removal device 100 out of the geothermal well through the hollow drill pipe, and restores normal production of the geothermal well.

[0086] In the description of the present invention, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of the technical features indicated. Therefore, a feature specified as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, "plurality" means two or more, unless otherwise specifically defined.

[0087] In the present invention, unless otherwise expressly specified or limited, the terms "mounted," "connected," "connect," "fixed," etc. should be understood broadly. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediary; or internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0088] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "examples," "specific examples," or "some examples" means that a specific feature, structure, material, or characteristic described in conjunction with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0089] Finally, it should be noted that the above description is merely a preferred embodiment of the present invention and does not constitute any limitation to the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments or to replace some of the technical features therein with equivalents. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the scope of protection of the present invention.

Claims

1. A device for removing scale and rust from a well wall, characterized in that: include: Hollow tube (2); an ultrasonic thickness gauge (3) disposed on the hollow tube (2); an injection mechanism (4) provided at the lower end of the hollow tube (2), the injection mechanism (4) being connected to a chemical descaling agent barrel (13) and a chemical descaling agent barrel (14); a blocking bridge plug (6) provided at the lower end of the injection mechanism (4), wherein the blocking bridge plug (6) is configured to repeatedly block the well wall; as well as The data analysis module (10), the ultrasonic thickness gauge (3), the injection mechanism (4) and the blocking bridge plug (6) are all electrically connected to the data analysis module (10).

2. The well wall descaling and rust removal device according to claim 1, characterized in that: The injection mechanism (4) comprises: a liquid cylinder (407), wherein a liquid discharge valve (408) is provided in the liquid cylinder (407); A piston cylinder (403), wherein the piston cylinder (403) is movably sealed and disposed in the liquid cylinder (407), and a liquid inlet valve (406) is disposed in the piston cylinder (403), and the two ends of the liquid inlet valve (406) are respectively connected to the inner cavity of the piston cylinder (403) and the inner cavity of the liquid cylinder (407); and The nozzle (410) is connected to the inner cavity of the liquid cylinder (407) and the nozzle (410) at both ends of the liquid discharge valve (408); The discharge valve (408) and the inlet valve (406) are both configured to only allow the fluid to flow in one direction from the piston cylinder (403) to the nozzle (410).

3. The well wall descaling and rust removal device according to claim 2, characterized in that: The liquid inlet valve (406) includes a first sealing member (41) sealed in the cavity of the piston cylinder (403), a first flow hole (42) is axially penetrated on the first sealing member (41), a second flow hole (40) is provided at the lower end of the piston cylinder (403) and is connected to the inner cavity of the liquid cylinder (407), a first spring (43) is provided between the first sealing member (41) and the lower end of the piston cylinder (403), and a first sealing block (44) is provided at the upper end of the first spring (43) to block the first flow hole (42).

4. The well wall descaling and rust removal device according to claim 2, characterized in that: The drain valve (408) includes a second sealing member (46) sealed in the cavity of the liquid cylinder (407), a third flow hole (47) is axially penetrated on the second sealing member (46), a fourth flow hole (45) connected to the inner cavity of the nozzle (410) is provided at the lower end of the liquid cylinder (407), a second spring (48) is provided between the second sealing member (46) and the lower end of the liquid cylinder (407), and a second sealing block (49) is provided at the upper end of the second spring (48) to block the third flow hole (47).

5. The well wall descaling and rust removal device according to claim 2, characterized in that: The injection mechanism (4) further comprises a connecting sleeve (402), the liquid cylinder (407) is fixedly connected to the connecting sleeve (402), an upper joint (401) is connected to the upper end of the piston cylinder (403), and the connecting sleeve (402) and the upper joint (401) are axially movable and limitedly connected.

6. The well wall descaling and rust removal device according to any one of claims 1 to 5, characterized in that: The blocking bridge plug (6) comprises: Bridge plug rod (601); A plurality of sealing rods (605) are evenly arranged on the bridge plug rod (601) along the circumferential direction. One end of each sealing rod (605) is hinged to the bridge plug rod (601), and the other end is used for sealing with the well wall.

7. The well wall descaling and rust removal device according to claim 6, characterized in that: A sliding sleeve (602) is axially movably provided on the bridge plug rod (601), and a folding support rod (603) is hinged between the sliding sleeve (602) and each sealing support rod (605).

8. The well wall descaling and rust removal device according to claim 7, characterized in that: An electromagnetic connection shaft (5) is provided at the upper end of the bridge plug rod (601), and the sliding sleeve (602) is configured to be able to move up and down along the bridge plug rod (601) in response to the electromagnetic force of the electromagnetic connection shaft (5).

9. A method for removing scale and rust from a well wall, characterized in that: The steps include: Inserting the well wall descaling and rust removal device according to any one of claims 1 to 8 into the well to a predetermined depth; The well wall descaling and rust removal device is rotated and raised, and at the same time, the ultrasonic thickness gauge is used to measure the well wall to determine whether descaling or rust removal is required; When removing scale or rust, the well wall descaling and rust removal device stops rotating and rising, the blocking bridge plug blocks the wellbore, and the injection mechanism sprays chemical reagents onto the well wall.

10. The method for removing scale and rust from a well wall according to claim 9, characterized in that: When descaling or rust removal is completed, the jetting mechanism sprays cleaning water onto the well wall for cleaning.

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