Wax and scale removal device and method for rodless oil production well

Abstract

Disclosed is a wax and scale removal device for a rodless oil production well, comprising: a wellhead blowout prevention structure, wherein the wellhead blowout prevention structure comprises a blowout prevention pipe (6), a blowout prevention cap (1) is connected to the top end of the blowout prevention pipe (6), and a liftable / lowerable drop bar (3) is arranged in the blowout prevention cap (1); a plunger structure comprising a plunger body (8) and a steel ball (9), wherein the steel ball (9) can block the bottom end of a plunger center hole under the action of an upward axial force or leave under the impact of the drop bar (3) to make the plunger center hole through-going, a blade structure is connected to the plunger body (8), and the blade structure can rotate to continuously and automatically remove wax and scale; and a downhole seating tool comprising a crossover sub (18), wherein a steel ball bearing joint (16) is connected to the crossover sub (18). The plunger structure moves up and down in a circular manner in an oil pipe to scrape wax and scale off the pipe wall, so that continuous and automatic wax and scale removal in the entire well section can be achieved, and the plunger can be automatically captured on the basis of the degree of wax and scale formation in the shaft. Also disclosed is a method of using the device.

Description

Rodless oil well wax and scale removal device and method

[0001] Related applications

[0002] This application claims priority to the Chinese invention patent with patent application number 202310774266.0, application date June 28, 2023, and invention name “Device and method for cleaning wax and scale of rodless oil wells”. Technical Field

[0003] The present invention relates to the field of oil production engineering in the petroleum industry, and in particular to a device and method for removing wax and scale from a rodless oil well. Background Art

[0004] During crude oil extraction, changes in temperature, pressure, flow rate, and other factors can cause wax and inorganic salts to deposit in the tubing, leading to wax and scaling in the well. Wax and scaling in the well reduce the flow cross-section for fluid lift, increase fluid flow resistance, affect the normal operation of oil well equipment, and reduce well production.

[0005] Existing thermal wax removal techniques pose safety risks due to the need to heat crude oil. This can cause the water content in oil wells to increase, and can even cause oil wells to stop flowing, impacting oil production. Commonly used mechanical wax removal methods involve lowering wax scrapers and wax removal drills into the wellbore via a steel wire, and then manually lifting and lowering the wire to remove the wax, which is labor-intensive. Common descaling processes involve adding antiscaling agents and corrosion inhibitors to keep scale-forming cations in solution, resulting in complex operations and high costs.

[0006] Chinese patent (CN206220931U) discloses a rodless oil well mechanical wax removal device that uses well fluid to push a sealing rubber plug and wax scraper upward to remove wax. The device increases the outer diameter of the oil pipe at the reversing pipe, allowing fluid to be discharged from the annulus between the reversing pipe, the sealing rubber plug, and the wax scraper. This results in a small flow area. Furthermore, the device continuously scrapes wax without stopping the pump. The well fluid continuously flows upward, leaving the plunger without a flow channel. This creates a constant bottom thrust on the plunger within the oil pipe, preventing the sealing rubber plug and wax scraper from falling in time. If they do fall to the baffle, they will significantly impact it.

[0007] A Chinese patent (CN218816343U) discloses a rodless oil production machine anti-scaling and anti-wax device. The oil pipe equipped with the anti-scaling and anti-wax device is inserted into the location prone to wax deposition to perform local anti-scaling and anti-wax. However, the location prone to wax deposition is not easy to accurately determine and find. At the same time, the fluid constantly rotates in the opposite direction, which reduces the fluid flow rate and affects the lifting effect.

[0008] A Chinese patent (CN103306640A) discloses a hydraulic wax removal device for a rodless pump oil production system, which performs wax removal operations by controlling the start and stop of an electric submersible pump, but cannot achieve continuous automatic wax removal.

[0009] A Chinese patent (CN201386526Y) discloses a plunger capture device for a plunger gas lift wellhead. When the plunger needs to be repaired, the plunger is removed manually, but the timing of the plunger repair cannot be accurately determined manually.

[0010] Therefore, the inventors, relying on their many years of experience and practice in related industries, have proposed a rodless oil well wax and scale removal device and method to overcome the defects of the prior art.

[0011] Summary of the Invention

[0012] The purpose of the present invention is to provide a rodless oil well wax and scale cleaning device and method, which scrapes wax scale from the pipe wall through the up and down circular motion of the plunger structure in the oil pipe, overcomes the increase in water content caused by hot washing of the oil well and the labor cost caused by mechanical wax cleaning in the prior art, ensures safe and environmentally friendly construction and reduces operating costs, can realize continuous and automatic wax and scale cleaning in the entire well section, and can automatically capture the plunger according to the degree of wax and scale accumulation in the wellbore.

[0013] The object of the present invention is achieved by providing a rodless oil well wax and scale removal device, comprising:

[0014] The wellhead blowout prevention structure includes a lubricant pipe connected to the top of the oil pipe, a detachable blowout cap at the top of the lubricant pipe, a liftable impact rod disposed within the blowout cap, and a wellhead flange and a plunger catcher connected to the side wall of the lubricant pipe;

[0015] The plunger structure includes a plunger body capable of reciprocating up and down and a steel ball. A plunger center hole is axially penetrated in the plunger body. The outer diameter of the plunger body in a free state is smaller than the inner diameter of the oil pipe. After the plunger body is pressurized and expanded, the outer diameter of the plunger body is larger than the inner diameter of the oil pipe. The impact rod can pass through the plunger center hole. The steel ball can block the bottom end of the plunger center hole under the action of an upward axial force or move away under the impact of the impact rod to allow the plunger center hole to penetrate. A blade structure is connected to the plunger body. The blade structure can rotate under the action of hydraulic pressure to continuously and automatically remove wax and scale.

[0016] The downhole seat includes a variable buckle joint that can be connected to the oil pipe. The variable buckle joint is connected to the steel ball bearing joint. The variable buckle joint has a joint center hole axially extending therethrough. The bottom end of the variable buckle joint is provided with a liquid passage connected to the joint center hole.

[0017] The object of the present invention can also be achieved in this way. A method for cleaning wax and scale in a rodless oil well comprises the following steps: preparing the aforementioned rodless oil well cleaning wax and scale cleaning device; pre-setting a downhole seat in the wellbore along with the oil pipe; lowering a steel ball and a plunger body into the oil pipe through the top end of the blowout preventer; the steel ball blocks the plunger body; the top end of the blowout preventer is connected to the blowout cap; well fluid enters the oil pipe through the liquid passage on the downhole seat, pushing the steel ball and the plunger body upward, and the liquid flow acts on the blade structure, which rotates to remove wax and scale; the plunger structure moves upward to the wellhead, and the well fluid is discharged through the wellhead flange. When the plunger body contacts the pressure sensing plate, the impact rod extends and knocks down the steel ball, which is counted once;

[0018] The plunger body falls, and the steel ball and the plunger body fall onto the downhole seat again. The steel ball blocks the plunger body again, and the liquid lifts it to perform another reciprocating motion to remove wax and dirt, and counts again. When the plunger body contacts the pressure sensing plate for a set number of times, the impact rod no longer extends, and the plunger catcher captures the plunger structure, the blowout preventer is removed, and the plunger structure is taken out.

[0019] As described above, the rodless oil well wax and scale removal device and method of the present invention have the following beneficial effects:

[0020] The rodless oil well wax and scale cleaning device of the present invention is easy to install. The plunger structure moves upward by relying on the lifting effect of the well fluid and does not require its own power. It can be applied to rodless oil wells, gas lift oil wells, self-flowing wells and other rodless oil wells. The plunger structure can automatically fall down by impacting the impact rod without affecting the liquid flow area and the lifting effect, thereby realizing continuous and automatic wax and scale cleaning in the entire well section. The downhole seat cushions the plunger structure, and the device has good stability. The wax and scale cleaning method of the present invention is simple and easy to operate. The wax and scale cleaning times are set according to the degree of wax and scale accumulation in the wellbore, and the plunger is automatically captured to facilitate subsequent repair and maintenance. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] 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 description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0022] in:

[0023] FIG1 is a schematic diagram of the rodless oil well wax and scale removal device of the present invention.

[0024] FIG2 is a schematic diagram of the plunger structure of the present invention.

[0025] FIG3 is a top view of the upper blade of the present invention.

[0026] FIG4 is a schematic diagram of the steel ball anti-slip claw of the present invention.

[0027] FIG5 is a schematic diagram of the downhole seat of the present invention.

[0028] Figure 6: AA cross-sectional view in Figure 5.

[0029] FIG7 is a flow chart of the rodless oil well wax and scale removal method of the present invention. DETAILED DESCRIPTION

[0030] In order to have a clearer understanding of the technical features, purposes and effects of the present invention, specific embodiments of the present invention are now described with reference to the accompanying drawings.

[0031] The specific embodiments of the present invention described herein are intended only to illustrate the present invention and are not to be construed as limiting the present invention in any way. In light of the present invention, a skilled person may conceive of any possible variations based on the present invention, all of which should be considered to fall within the scope of the present invention. It should be noted that when an element is referred to as being "disposed on" another element, it may be directly on the other element or there may be an intermediate element. When an element is considered to be "connected" to another element, it may be directly connected to the other element or there may be an intermediate element at the same time. The terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to mechanical or electrical connections, or to internal communication between two elements, and may be directly connected or indirectly connected through an intermediate medium. A person of ordinary skill in the art can understand the specific meanings of the above terms based on the specific circumstances. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only implementation methods.

[0032] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application pertains. The terms used herein in the specification of this application are intended only to describe specific embodiments and are not intended to limit this application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0033] As shown in Figures 1 to 6, the present invention provides a rodless oil well wax and scale removal device, comprising:

[0034] The wellhead blowout prevention structure includes a lubricant pipe 6 connected to the top of the oil pipe. The top of the lubricant pipe 6 can be detachably connected to the blowout cap 1. The blowout cap 1 is provided with a liftable impact rod 3. The side wall of the lubricant pipe 6 is connected to the wellhead flange 5 and the plunger catcher 7.

[0035] The plunger structure includes a plunger body 8 and a steel ball 9 that can reciprocate up and down. A plunger center hole is axially penetrated in the plunger body 8. The outer diameter of the plunger body 8 is smaller than the inner diameter of the oil pipe in a free state. After the plunger body 8 is pressurized and expanded, the outer diameter of the plunger body 8 is larger than the inner diameter of the oil pipe. The impact rod 3 can pass through the plunger center hole. The steel ball 9 can block the bottom end of the plunger center hole under the action of an upward axial force or move away under the impact of the impact rod 3 to allow the plunger center hole to penetrate. A blade structure is connected to the plunger body 8. The blade structure can rotate under the action of hydraulic pressure to continuously and automatically remove wax and scale.

[0036] Downhole seat 10 includes a variable-slip joint 18 that can be connected to the oil pipe. A steel ball bearing joint 16 is connected to variable-slip joint 18, which cushions the falling plunger structure. A central hole is axially extending through variable-slip joint 18, and a fluid passage 19 is provided at the bottom end of variable-slip joint 18, communicating with the central hole. Well fluid enters oil pipe 11 through fluid passage 19 in downhole seat 10, pushing steel ball 9 and plunger body 8 upward, forming the power source for the rodless oil well dewaxing and descaling device of the present invention.

[0037] When the blowout preventer 1 is removed, the plunger structure is put in and taken out from the top of the lubricator 6; the wellhead flange 5 is used for drainage; the number of plunger wax and scale cleaning times is set according to the plunger running speed. When the number of plunger running times reaches the set number of plunger wax and scale cleaning times, the plunger catcher 7 automatically captures the plunger structure; during normal production, the impact rod 3 is installed on the top of the lubricator 6. After the plunger body 8 reaches the top, the impact rod 3 can push open the steel ball 9, and the plunger center hole in the plunger body 8 passes liquid. There is a liquid passage inside the plunger body 8, and there is no lifting effect of the well fluid. The plunger body 8 falls under the action of gravity; during maintenance and inspection, the blowout preventer 1 is opened and the impact rod 3 is removed to prevent the steel ball 9 at the bottom of the plunger body 8 from falling to the bottom of the well.

[0038] Steel ball 9 blocks the bottom of the plunger's central hole under the action of an upward axial force. The steel ball 9 and plunger body 8 move upward under the lifting force of the fluid flow. In its free state, the plunger body 8 has an outer diameter smaller than the inner diameter of the tubing. After expansion under pressure, the outer diameter of the plunger body 8 becomes larger than the inner diameter of the tubing. The blade structure rotates under the action of hydraulic pressure to continuously and automatically remove wax and scale.

[0039] During the upward movement of the plunger structure to remove wax and scale, it is inevitable that the removed wax and scale will adhere to the blades and other components, so the plunger structure needs to be regularly inspected and maintained. The plunger structure relies on the lifting effect of the well fluid to move upward. The speed of the plunger structure can represent the speed of the well fluid flow. The increase in the crude oil flow rate will shorten the flow time of the crude oil in the wellbore, and the wax and scale formation can be alleviated. Then the well fluid flow rate can reflect the degree of wax and scale formation in the wellbore. Therefore, the number of times the plunger cleans wax and scale can be set according to the plunger running speed. When the number of times the plunger structure runs reaches the set number of times the plunger cleans wax and scale, the plunger structure is automatically captured, and then the spray preventer 1 is opened to remove the plunger body 8.

[0040] The rodless oil well wax and scale cleaning device of the present invention is easy to install. The plunger structure moves upward by relying on the lifting effect of the well fluid and does not require its own power. It can be applied to rodless oil wells, gas lift oil wells, self-flowing wells and other rodless oil wells. The plunger structure can automatically fall down by impacting the impact rod without affecting the liquid flow area and the lifting effect, thereby realizing continuous and automatic wax and scale cleaning in the entire well section. The downhole seat cushions the plunger structure, and the device has good stability. The wax and scale cleaning method of the present invention is simple and easy to operate. The wax and scale cleaning times are set according to the degree of wax and scale accumulation in the wellbore, and the plunger is automatically captured to facilitate subsequent repair and maintenance.

[0041] Furthermore, as shown in FIG1 , a first buffer spring 2 is provided in the blowout preventer 1 , and the impact rod 3 can be axially contracted in the first buffer spring 2 . The first buffer spring 2 is used to reduce the impact strength of the plunger structure, protect the wellhead blowout preventer structure, and improve the stability of the device.

[0042] Furthermore, as shown in Figure 1, a pressure sensing sheet 4 is provided at the bottom end of the spray preventer 1. The pressure sensing sheet 4 is used to sense the contact of the plunger structure. When the plunger structure runs and contacts the pressure sensing sheet 4, the impact rod 3 extends from the first buffer spring 2 and passes through the center hole of the plunger to knock down the steel ball 9.

[0043] The impact rod 3 is normally located in the first buffer spring 2. When the plunger body 8 runs to the wellhead and contacts the pressure sensing plate 4, the impact rod 3 extends from the first buffer spring 2 and hits the steel ball 9. The length of the impact rod 3 is greater than the length of the plunger body 8 to meet the impact requirements.

[0044] Furthermore, as shown in Figures 1, 2, and 3, the blade structure includes an upper blade 12 and a lower blade 14 spaced axially along the plunger body. Upper blade 12 and lower blade 14 are rotatably connected to plunger body 8 via thin-walled ball bearings 13, which are designed to withstand mechanical motion loads. Spiral grooves are provided on both blades 12 and 14, and liquid flows through the grooves, causing the blades to rotate and remove wax and scale.

[0045] Furthermore, as shown in Figures 1, 2, and 4, the bottom end of the plunger body 8 is connected to the anti-steel ball slip claw 15. The steel ball 9 can enter the anti-steel ball slip claw 15 under the action of the upward axial force to block the plunger center hole, or leave the anti-steel ball slip claw 15 under the top pressure of the impact rod 3. When the steel ball 9 and the plunger body 8 fall onto the downhole seat 10, the steel ball 9 enters the anti-steel ball slip claw 15 under the upward supporting force of the downhole seat 10.

[0046] Furthermore, as shown in FIG4 , the steel ball anti-slip claw includes a claw ring body, on which a claw petal body is provided, the bottom end of which can be extended and retracted in the radial direction.

[0047] In a specific embodiment of the present invention, the anti-steel ball slipping claw adopts an elastic claw structure with six inner mouth bosses. The steel ball 9 can enter the anti-steel ball slipping claw under the action of very small force. When there is no external force, the steel ball 9 will not slip out of the anti-steel ball slipping claw 15. The steel ball 9 is located in the anti-steel ball slipping claw 15 during the upward process, playing a single-flow role.

[0048] Furthermore, as shown in Figures 1 and 5, a variable-slip joint 18 is used to connect the downhole seat 10 and the oil pipe 11. A joint connecting shaft is passed through the variable-slip joint 18, the top end of which is connected to the steel ball bearing joint 16. A second buffer spring 17 is sleeved on the joint connecting shaft to axially cushion the steel ball bearing joint. Second buffer spring 17 cushions the falling plunger body 8 and steel ball 9, improving the stability of the device.

[0049] Furthermore, as shown in FIG1 and FIG5 , an inner chamfered groove is provided at the center of the top end of the steel ball bearing joint 16 to facilitate centering of the steel ball 9 .

[0050] 1 and 6, the fluid passage 19 includes a plurality of oil holes spaced circumferentially at the bottom end of the variable buckle joint, through which the well fluid flows upward. In a specific embodiment of the present invention, the number of the oil holes is 8, and the diameter is 12 mm.

[0051] The present invention also provides a rodless oil well wax and scale removal method, comprising: preparing the aforementioned rodless oil well wax and scale removal device; pre-setting a downhole seat 10 in the wellbore along with an oil pipe 11; lowering a steel ball 9 and a plunger body 8 into the oil pipe through the top of a blowout preventer 6; the steel ball 9 blocks the plunger body 8; and the top of the blowout preventer 6 is connected to a blowout cap 1; well fluid enters the oil pipe 11 through a liquid passage 19 on the downhole seat 10, pushing the steel ball 9 and the plunger body 8 upward, and the liquid flow acts on a blade structure, which rotates to remove wax and scale; the plunger structure moves upward to the wellhead, and the well fluid is discharged through the wellhead flange 5. When the plunger body contacts the pressure sensing plate, the impact rod 3 extends and knocks down the steel ball 9, which is counted once;

[0052] The plunger body 8 falls, and the steel ball 9 and the plunger body 8 fall onto the downhole seat 10 again. The steel ball 9 blocks the plunger body 8 again, and the liquid is used to lift the plunger body 8 to perform another reciprocating motion for wax and dirt removal, and the count is repeated once more. When the plunger body 8 contacts the pressure sensing plate 4 for a set number of times, the impact rod 3 no longer extends, and the plunger catcher 7 captures the plunger structure. The blowout preventer 1 is disassembled and the plunger structure is taken out.

[0053] The rodless oil well wax and scale removal method of the present invention sets the number of wax and scale removal operations of the plunger structure according to the degree of wax and scale deposition. When the plunger structure has operated for the set number of times, the plunger structure is automatically captured. The wax and scale removal method specifically includes the following steps (as shown in the flowchart in FIG7 ):

[0054] S1: The downhole seat 10 is pre-installed in the wellbore along with the oil pipe 11. The blowout preventer 1 is opened, and the steel ball 9 and the plunger body 8 are lowered in sequence. After the blowout preventer 1 is installed, the steel ball 9 and the plunger body 8 fall by their own gravity onto the steel ball bearing joint 16 on the downhole seat 10. Under the action of axial force, the steel ball 9 enters the steel ball anti-slip claw 15 of the plunger body 8, and the second buffer spring 17 plays a buffering role on the falling plunger body 8 and steel ball 9.

[0055] S2: The well fluid enters the oil pipe 11 through the liquid passage 19 on the downhole seat 10, pushing the steel ball 9 to move upward. The steel ball 9 is in close contact with the anti-steel ball slip claw 15 of the plunger body 8, pushing the plunger body 8 to move upward. The liquid flow acts on the spiral grooves of the upper blade 12 and the lower blade 14, and the upper blade 12 and the lower blade 14 rotate to remove wax and scale.

[0056] S3: The plunger structure moves upward to the wellhead, and the well fluid is discharged through the wellhead flange 5. When the plunger body 8 contacts the pressure sensing plate 4, the impact rod 3 extends from the first buffer spring 2 and hits the steel ball 9. The first buffer spring 2 acts as a buffer for the plunger body 8, and the steel ball 9 falls. The time t1 when the plunger body 8 first contacts the pressure sensing plate 4 is recorded and counted once, and the count i=1.

[0057] S4: The steel ball 9 with a single-flow function falls, and the center hole of the plunger is connected, so that there is a liquid passage inside the plunger body 8, and there is no lifting effect of the well fluid. The plunger body 8 falls under the action of gravity, and the steel ball 9 and the plunger body 8 fall again onto the steel ball bearing joint 16. The steel ball 9 enters the anti-steel ball slip claw 15 again, and uses the liquid lifting to perform another reciprocating motion for wax and dirt removal.

[0058] S5: Record the time t2 when the plunger body 8 contacts the pressure sensing plate 4 for the second time and count it once, i=2. The speed v of the plunger structure in one reciprocating motion is:

[0059] Where L is the length of the oil pipe.

[0060] S6: The number of times N the plunger cleans wax and scale is removed is set based on the plunger speed v. The greater the plunger speed v, the fewer times N the plunger cleans wax and scale is set. When the plunger body 8 contacts the pressure sensing plate 4 for a number i=N, the impact rod 3 no longer extends, and the plunger structure is captured by the plunger catcher 7. The spray preventer 1 is disassembled and the plunger structure is removed.

[0061] As described above, the rodless oil well wax and scale removal device and method of the present invention have the following beneficial effects:

[0062] The rodless oil well wax and scale cleaning device of the present invention is easy to install. The plunger structure moves upward by relying on the lifting effect of the well fluid and does not require its own power. It can be applied to rodless oil wells, gas lift oil wells, self-flowing wells and other rodless oil wells. The plunger structure can automatically fall down by impacting the impact rod without affecting the liquid flow area and the lifting effect, thereby realizing continuous and automatic wax and scale cleaning in the entire well section. The downhole seat cushions the plunger structure, and the device has good stability. The wax and scale cleaning method of the present invention is simple and easy to operate. The wax and scale cleaning times are set according to the degree of wax and scale accumulation in the wellbore, and the plunger is automatically captured to facilitate subsequent repair and maintenance.

[0063] The above description is only an illustrative embodiment of the present invention and is not intended to limit the scope of the present invention. Any equivalent changes and modifications made by those skilled in the art without departing from the concept and principle of the present invention shall fall within the scope of protection of the present invention.

Claims

1. A rodless oil well wax and scale removal device, wherein: include, The wellhead blowout prevention structure comprises a blowout prevention pipe connected to the top of the oil pipe, the top of the blowout prevention pipe is detachably connected to a blowout prevention cap, a lifting and lowering impact rod is arranged inside the blowout prevention cap, and a wellhead flange and a plunger catcher are connected and arranged on the side wall of the blowout prevention pipe; The plunger structure comprises a plunger body and a steel ball capable of reciprocating up and down. A plunger center hole is axially penetrated in the plunger body. The outer diameter of the plunger body is smaller than the inner diameter of the oil pipe in a free state, and the outer diameter of the plunger body is larger than the inner diameter of the oil pipe after being expanded under pressure. The impact rod can pass through the plunger center hole. The steel ball can block the bottom end of the plunger center hole under the action of an upward axial force or leave under the impact of the impact rod to make the plunger center hole penetrate. A blade structure is connected to the plunger body, and the blade structure can rotate under the action of hydraulic force to continuously and automatically remove wax and scale. The downhole seat comprises a variable buckle joint that can be connected to the oil pipe, the variable buckle joint is connected to a steel ball bearing joint, a joint center hole is axially arranged in the variable buckle joint, and a liquid passage connecting to the joint center hole is arranged at the bottom end of the variable buckle joint.

2. The rodless oil well wax and scale removal device according to claim 1, wherein: A first buffer spring is arranged in the spray-proof cap, and the impact rod can be axially contracted in the first buffer spring, and the first buffer spring is used to mitigate the impact strength of the plunger structure.

3. The rodless oil well wax and scale removal device according to claim 2, wherein: A pressure sensing sheet is provided at the bottom end of the spray cap, and the pressure sensing sheet is used to sense the contact of the plunger structure. When the plunger structure runs and contacts the pressure sensing sheet, the impact rod extends from the first buffer spring and passes through the center hole of the plunger to knock down the steel ball.

4. The rodless oil well wax and scale removal device according to claim 1, wherein: The blade structure comprises an upper blade and a lower blade spaced axially along the plunger body, and the upper blade and the lower blade are rotatably connected to the plunger body via thin-walled ball bearings respectively.

5. The rodless oil well wax and scale removal device according to claim 1, wherein: The bottom end of the plunger body is connected to the anti-slip claw. The steel ball can enter the anti-slip claw to block the plunger center hole under the action of the upward axial force or leave the anti-slip claw under the top of the impact rod.

6. The rodless oil well wax and scale removal device according to claim 5, wherein: The anti-slip claw of the steel ball comprises a claw ring body, and the claw ring body is provided with a claw petal body whose bottom end can be extended and retracted in radial direction.

7. The rodless oil well wax and scale removal device according to claim 1, wherein: A joint connecting shaft is passed through the variable buckle joint, the top end of the joint connecting shaft is connected to the steel ball bearing joint, and a second buffer spring capable of axially buffering the steel ball bearing joint is sleeved on the joint connecting shaft.

8. The rodless oil well wax and scale removal device according to claim 7, wherein: An inner chamfered groove is arranged at the center of the top end of the steel ball bearing joint.

9. The rodless oil well wax and scale removal device according to claim 7, wherein: The liquid passage includes a plurality of oil holes arranged at intervals along the circumferential direction at the bottom end of the variable buckle joint.

10. A method for removing wax and scale from a rodless oil well, wherein: include, A rodless oil well wax and scale removal device as described in any one of claims 1 to 9 is prepared, the downhole seat is pre-set in the wellbore along with the oil pipe, a steel ball and a plunger body are lowered into the oil pipe through the top of the blowout preventer, the steel ball blocks the plunger body, and the top of the blowout preventer is connected to the blowout cap; the well fluid enters the oil pipe through the liquid passage on the downhole seat, pushing the steel ball and the plunger body to move upward, and the liquid flow acts on the blade structure, and the blade structure rotates to remove wax and scale; The plunger structure moves upward to the wellhead, and the well fluid is discharged through the wellhead flange. When the plunger body contacts the pressure sensing sheet, the impact rod extends and knocks down the steel ball, which counts once. The plunger body falls, and the steel ball and the plunger body fall onto the downhole seat again. The steel ball blocks the plunger body again, and the liquid is used to lift the plunger body to perform another reciprocating motion for wax and dirt removal, which is counted again. When the plunger body contacts the pressure sensing plate for a set number of times, the impact rod no longer extends, and the plunger catcher captures the plunger structure, the spray preventer is removed, and the plunger structure is taken out.

11. The rodless oil well dewaxing and descaling method according to claim 10, wherein: The following steps are involved: S1: The downhole seat is pre-set in the wellbore with the oil pipe, the blowout preventer is opened, the steel ball and the plunger body are lowered in sequence, the blowout preventer is installed, the steel ball and the plunger body fall to the steel ball bearing joint of the downhole seat by their own gravity, and the steel ball enters the steel ball slip prevention claw of the plunger body under the action of the axial force; S2: Well fluid enters the oil pipe through the liquid passage on the downhole seat, pushing the steel ball and the plunger body upward. The liquid flow acts on the spiral grooves of the upper blade and the lower blade, and the upper blade and the lower blade rotate to remove wax and scale; S3: The plunger structure moves upward to the wellhead, and the well fluid is discharged through the wellhead flange. When the plunger body contacts the pressure sensing sheet, the impact rod extends from the first buffer spring and hits the steel ball, causing the steel ball to fall. The time t1 when the plunger body first contacts the pressure sensing sheet is recorded and counted once, with the count i=1. S4: The steel ball falls, the center hole of the plunger is connected, and the plunger body falls under the action of gravity. The steel ball and the plunger body fall onto the steel ball bearing joint again, and the steel ball enters the anti-slip claw again, and is lifted again by liquid. One-time reciprocating motion for wax and dirt removal; S5: Record the time t2 when the plunger body contacts the pressure sensing sheet for the second time, and count once, count i=2; the speed v of the plunger structure in a reciprocating motion: Where L is the length of the oil pipe; S6: Set the number of times N for the plunger to clean wax and dirt according to the plunger running speed v; when the number of times the plunger body contacts the pressure sensing plate i=N, the impact rod no longer extends, the plunger catcher automatically catches the plunger structure, removes the spray cap, and takes out the plunger structure.

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