Device for paraffin removal or blockage flushing of oil well pipe column and application and use method of device for paraffin removal or blockage flushing of oil well pipe column

Abstract

The invention discloses a device for paraffin removal or blockage flushing of an oil well pipe column and application and using method. The device comprises a shell, an inner container base, an inner container and a righting assembly. The inner container seat is arranged at the lower end of the interior of the shell, the inner container is arranged in the shell and sits on the inner container seat when falling down, and the righting assembly is arranged in the shell in a sleeved mode and used for helping the inner container to smoothly sit on the inner container seat for sealing when falling down; a spring, a valve element and a valve seat are arranged in the inner container, when the pressure borne by the valve element is larger than the elastic force of the spring, the spring is compressed, the inner portion of the inner container is communicated, cleaning liquid can be directly pumped into an oil well pipe column from a well mouth through ground pressurization equipment, and when the pipe column or an oil well pump is blocked by sundries, blocking objects in the pipe column or the oil well pump can be flushed. When paraffin is deposited on the inner wall of an oil well tubular column, the cleaning liquid is changed into high-temperature hot water to be pumped into the tubular column to directly contact with the paraffin on the inner wall of the oil well tubular column to be quickly melted and removed, oil well production is recovered, well shutdown time and paraffin removal and well and pump repair cost are reduced, and economic benefits are greatly improved.

Description

Technical Field

[0001] The present invention relates to the technical field of oil production engineering, and particularly to a device for wax removal or flushing of blockages in oil well tubing, as well as its application and usage method. Background Art

[0002] In oilfield production, in the production process of oil wells with high wax content, paraffin will continuously deposit on the inner surface of the upper part of the oil well tubing where the temperature is relatively low. As the production time increases, more and more paraffin deposits inside the oil well tubing, resulting in tubing blockage.

[0003] For the wax deposition blockage of the tubing of a sucker rod pump oil well, especially the tubing of a beam pump oil well, the commonly used treatment method at present is to inject high-temperature hot water into the well from the casing, so that the high-temperature hot water flows downward in the annulus between the casing and the tubing, in order to heat the tubing with the high-temperature hot water. The heat is transferred from the outer wall of the tubing to the inner wall of the tubing and then conducted to the deposited paraffin. However, in this method, since the heat is transferred from the outer wall of the tubing to the inner wall of the tubing, the heat is also transferred to the casing, resulting in a great loss of heat. In addition, the downward flow rate of the hot water is very fast, and the actual heating time and heat for the paraffin blocked inside the tubing are greatly lost, and the heat transfer efficiency is very low, causing a huge waste of heat, with a poor wax removal effect, a high wax removal cost, and varying degrees of impact on the formation. At the same time, for the tubing of an ESP oil well, a large amount of high-temperature hot water will have varying degrees of adverse effects on the cable and the unit. And in actual work, especially when the wax deposition blockage in the tubing of an ESP oil well is serious, it is very difficult to solve the problem with this method.

[0004] In an oil well with a lot of debris, when the sucker rod pump used is an ESP, the debris will block the impeller and diffuser of the ESP, resulting in an increased resistance to the rotation of the impeller or the inability to rotate. Whether it is tubing blockage or blockage of the impeller and diffuser of the ESP, it will affect the production of the oil well or even stop production.

[0005] When removing wax from the tubing of an ESP oil well, there is a method of using a wax scraper. If the wax deposition is serious, it is very difficult for the wax scraper to descend from the tubing, and it is basically impossible to succeed. When the wax deposition is light, although it can be scraped, the effect is not ideal. During the wax scraping process, the wax is easy to accumulate and block, and it is necessary to regularly remove wax, which is prone to accidents and the wax removal cost is very high.

[0006] There is also a method of directly lowering the heating cable into the tubing string after pulling out the downhole submersible pump oil well tubing string and before production, using a high-power thermal cable to keep wax from forming. There is also a method of using a high-power electric heating sucker rod for a rod pump to keep wax from forming. This method of wax removal is successful, but the input cost is too high and the economic efficiency is poor. For debris blocking the downhole submersible pump, the current method mainly involves applying additional power to the power system on the ground to forcibly drive the downhole motor to operate, and trying to eject the debris from the downhole submersible pump into the oil well tubing string as much as possible, and transporting it to the surface pipeline through the oil well tubing string. This method will have a greater impact on the service life of the motor and cable system. Importantly, the success rate is extremely low. When it is not successful, the downhole submersible pump needs to be pulled out of the well, flushed and repaired, and the cost is very high.

[0007] Publication (Announcement) No.: CN106437537B discloses a tubing string for pumping oil with a hot washing wax removal function, including a tubing extending in the up-down direction. A packer is strung below the wax deposition section of the tubing, and a sucker pump is connected to the bottom of the tubing. The packer is provided with a setting structure that is set when the tubing is pressured. In this way, before injecting hot washing liquid into the annulus between the casing and the tubing, the packer can be set in advance by pressurizing the tubing. After the packer is set, then inject hot washing liquid for hot washing wax removal. Only a small amount of hot washing liquid will enter the oil layer, with basically no pollution, protecting the oil layer. At the same time, since the packer is strung below the wax deposition section, the hot washing liquid can directly enter the wax deposition section, so the heat loss is very small, the heat energy is better utilized, the effect of hot washing wax removal is improved, and the amount of hot washing liquid used is small and the efficiency of hot washing wax removal is high.

[0008] The existing technology has a complex structure, high manufacturing and use costs, and is not very suitable for wax removal of downhole submersible pump oil well tubing due to pressure control problems, and it cannot flush the blockage in the downhole submersible pump.

[0009] Publication (Announcement) No.: CN206220931U discloses a mechanical wax removal device for a rodless oil production well. The wax removal device includes an upper reversing pipe, a wax scraper, a sealing rubber plug, and a lower baffle. The wax scraper and the sealing rubber plug are movably arranged inside the upper reversing pipe and the lower baffle from top to bottom in sequence. The wax removal device is located at the wax removal position of the oil production tubing string. The oil production tubing string includes a wax deposition area tubing and a non-wax deposition area tubing. The upper reversing pipe is connected to the upper part of the wax deposition area tubing, the lower baffle is fixedly installed at the lower part inside the wax deposition area tubing, the non-wax deposition area tubing is connected through to the lower part of the wax deposition area tubing, and the downhole submersible pump and the screen pipe are separately connected to the non-wax deposition area tubing from top to bottom in sequence, solving the problems of the oil well's water cut rising due to hot washing, short pump inspection period, and high maintenance operation costs. It has a delicate structure, is easy to install, does not require its own power supply, has great economic benefits, and can be promoted and used in various oilfields.

[0010] This prior art considers wax removal of oil well tubulars, but cannot flush blockages in electric submersible pumps, nor can it be used for sucker rod pump tubulars. This prior art has technical problems of easy jamming and malfunction in actual wax removal operations of oil well tubulars.

[0011] Publication (Announcement) No.: CN212837647U discloses a check valve and an electric submersible pump string, the check valve comprising: a body, having a first lower through hole, a second lower through hole and an upper through hole, the first lower through hole and the second lower through hole are arranged side by side, the upper end of the first lower through hole and the upper end of the second lower through hole are both connected to the lower end of the upper through hole; a forward sealing assembly, arranged in the first lower through hole and capable of controlling the opening and closing of the first lower through hole; a reverse sealing assembly, arranged in the second lower through hole and capable of controlling the opening and closing of the second lower through hole, a linkage assembly that makes the forward sealing assembly and the reverse sealing assembly linked and makes the opening and closing state of the first lower through hole opposite to the opening and closing state of the second lower through hole. This prior art can realize repeated forward well washing, and at the same time can prevent the sand and mechanical impurities carried by the liquid in the wellbore from descending and blocking the check valve.

[0012] This prior art cannot flush the electric submersible pump below the check valve when flushing the tubing string. This prior art has high requirements on the length accuracy of the connecting rod. Once the connecting rod is deformed underground, technical problems such as oil leakage will occur. This prior art also has the technical problem that extraction cannot be carried out when the connecting rod is broken.

[0013] In summary, the technical solutions of the above-disclosed technologies, the technical problems to be solved, and the beneficial effects produced are all different from the present invention. Regarding more technical features, technical problems to be solved, and beneficial effects of the present invention, the above-disclosed technical documents do not provide any technical inspiration. Summary of the invention

[0014] In view of the above-mentioned defects in the prior art, the purpose of the present invention is to provide a device, application and method for cleaning wax or flushing blockages in oil well tubing, so as to overcome the shortcomings of the prior art that the wax cannot be removed from the oil well tubing of the oil pump by hot melt and the blockages of the electric submersible pump cannot be flushed.

[0015] In order to achieve the above object, the present invention adopts the following technical solutions:

[0016] A device for clearing wax or flushing blockages from an oil well pipe column comprises an outer shell, an inner shell seat, an inner shell, and a straightening assembly; the inner shell seat is arranged at the lower end of the inner shell, the inner shell is arranged in the outer shell and sits on the inner shell seat when it falls, and the straightening assembly is sleeved in the outer shell and is used to help the inner shell to smoothly sit on the inner shell seat and seal when it falls; a spring, a valve core, and a valve seat are arranged in the inner shell, and when the pressure on the valve core is greater than the elastic force of the spring, the spring is compressed and the inner shell is conductive.

[0017] Furthermore, the shell includes an upper shell and a lower shell, the upper end of the lower shell is connected to the lower end of the upper shell, and the inner shell seat is arranged at the lower end of the inner wall of the lower shell.

[0018] Furthermore, the inner liner also includes an inner liner ball head, a lower fixing tube, an upper fixing tube, and a valve support;

[0019] Specifically, the lower part of the upper fixed tube is connected to the outer wall of the lower fixed tube; the inner bladder ball head is arranged at the lower end of the lower fixed tube;

[0020] Specifically, a through hole of the inner liner seat is arranged at the center of the inner liner seat, and the inner liner ball head can be seated on the through hole of the inner liner seat for sealing;

[0021] Specifically, the spring is placed in the lower fixed cylinder, the valve support is installed on the upper end of the spring, there is a hollow ball notch in the center of the upper surface of the valve support, the valve core sits in the hollow ball notch, and the valve seat is fixed on the upper end of the inner wall of the upper fixed cylinder;

[0022] Specifically, under the action of the spring, the valve core is pressed tightly against the center of the valve seat;

[0023] Specifically, the upper inner wall of the lower shell is connected to the lower outer wall of the upper shell, and the lower end of the inner wall of the lower shell is provided with two circular steps, which are divided into a first circular step and a second circular step, and the second circular step is above the first circular step;

[0024] Specifically, the inner liner seat is installed on the first circular step, and an elastic retaining ring is provided on the inner wall of the lower shell close to the upper surface of the inner liner seat, and the elastic retaining ring is embedded in the inner wall of the lower shell to prevent the inner liner seat from moving;

[0025] Specifically, a straightening assembly is installed above the second circular step.

[0026] Furthermore, the outer diameter of the inner container seat is the same as the inner diameter of the lower shell at the contact point, and the surface of the first circular step and the lower surface of the inner container seat are both flat and smooth;

[0027] Specifically, the upper shell and the lower shell are both circular hollow structures, the upper end of the upper shell is provided with an upper joint, the lower end of the lower shell is provided with a lower joint, and the inner wall of the upper end of the upper joint and the outer wall of the lower end of the lower joint are both provided with oil pipe threads;

[0028] Specifically, the inner wall of the lower end of the upper fixing tube is provided with an upper fixing tube connecting thread, and the outer wall of the lower fixing tube is provided with a lower fixing tube connecting thread;

[0029] Specifically, the upper fixing tube and the lower fixing tube are screwed together by upper and lower fixing tube connecting threads, and thread sealing or gasket sealing is adopted;

[0030] Specifically, an external thread for connecting the upper housing is provided on the outer wall at the lower end of the upper housing, and an internal thread for connecting the lower housing is provided on the inner wall at the upper end of the lower housing.

[0031] Specifically, the upper housing and the lower housing are screwed together through the upper and lower housing connection threads, and are sealed by thread or with a gasket.

[0032] Further, the lower fixing cylinder and the inner bladder ball head are integrally formed, and an inner bladder through hole with a diameter less than or equal to the inner diameter of the spring is provided at the center of the inner bladder ball head; the valve element is a valve ball, and the diameter of the hollow spherical segment is larger than the diameter of the valve ball.

[0033] Specifically, the upper and lower ends of the spring are ground into planes, the lower plane of the spring contacts the inner bottom surface of the lower fixing cylinder, and the lower fixing cylinder serves as a guide sleeve for the spring.

[0034] Specifically, the valve support includes a large cylinder and a small cylinder. The small cylinder is arranged at the lower end of the large cylinder. The outer diameter of the small cylinder is the same as the inner diameter of the spring and is inserted into the center of the spring. The lower plane of the large cylinder contacts the upper plane of the spring; the lower end surface of the large cylinder of the valve support is above the upper annular surface of the lower fixing cylinder, and the outer diameter of the large cylinder is smaller than the inner diameter of the upper fixing cylinder, so that the valve support can move up and down in the upper fixing cylinder. A first liquid passage is provided in the valve support.

[0035] Specifically, the valve seat and the upper fixing cylinder are screwed together, and are sealed by thread or with a gasket; a through hole is provided at the center of the valve seat; auxiliary mounting holes are provided on the upper surface of the valve seat.

[0036] In the first embodiment of the present invention, the alignment assembly is an alignment cylinder; the inner bladder is below the upper housing.

[0037] Specifically, the upper alignment legs and lower alignment legs are provided at the upper and lower ends of the alignment cylinder respectively. At least two upper alignment legs and at least two lower alignment legs are provided. A lower alignment leg ring is connected to the lower ends of the lower alignment legs. The upper end of the alignment cylinder is closed and the lower end is open.

[0038] Specifically, the upper part of the inner bladder is located inside the alignment cylinder.

[0039] Further, the lower alignment leg ring sits on the second circular step.

[0040] Specifically, the upper end surfaces of the upper alignment legs are below the bottom annular plane of the upper housing, and the bottom annular plane of the upper housing prevents the alignment cylinder from detaching.

[0041] Specifically, the diameters of the circles where the outer edges of the upper alignment legs and the lower alignment legs are located and the outer diameter of the lower alignment leg ring are the same as the inner diameter of the lower housing at their respective positions.

[0042] Specifically, the top surface of the upper part of the inner tank is below the inner top surface of the centering cylinder, enabling the inner tank to move up and down within the centering cylinder. A second liquid channel is formed between the inner wall of the centering cylinder and the outer wall of the upper fixing cylinder on the inner tank, and a third liquid channel is formed between the inner wall of the lower outer shell and the outer wall of the centering cylinder;

[0043] Specifically, at least one top notch is provided in the upper part of the upper fixing cylinder above the upper surface of the valve seat;

[0044] Specifically, the centering cylinder, the lower leg ring, the lower legs, and the upper legs are integrally formed or are detachably connected;

[0045] Specifically, the at least two upper legs and the at least two lower legs are evenly distributed along the circumferential direction of the centering cylinder.

[0046] In the second embodiment of the present invention, the centering assembly includes an upper centering ring, centering legs, a lower centering ring, and centering connection blocks; the inner tank is below the upper outer shell;

[0047] Specifically, the lower end of the centering leg is connected to the outer wall of the upper end of the upper fixing cylinder, the upper end of the centering leg is connected to the upper centering ring, and the lower centering ring is connected to the outer wall of the upper fixing cylinder through the centering connection blocks;

[0048] Specifically, the upper end surface of the upper centering ring is below the circular ring plane at the bottom of the upper outer shell, and the circular ring plane at the bottom of the upper outer shell prevents the inner tank from detaching;

[0049] Specifically, the upper centering ring, the centering legs, the lower centering ring, the centering connection blocks, and the upper fixing cylinder are integrally formed or are detachably connected;

[0050] Specifically, at least two centering legs are provided and are evenly distributed along the circumferential direction, and at least two centering connection blocks are provided and are evenly distributed along the circumferential direction.

[0051] In the third embodiment of the present invention, the centering assembly is a lower centering ring; the upper part of the inner tank extends into the central flow channel of the upper outer shell;

[0052] Specifically, the lower centering ring is connected to the outer wall of the upper fixing cylinder through the centering connection blocks;

[0053] Specifically, the upper end surface of the lower centering ring is below the circular ring plane at the bottom of the upper outer shell, and the circular ring plane at the bottom of the upper outer shell prevents the inner tank from detaching;

[0054] Specifically, the lower centering ring, the centering connection blocks, and the upper fixing cylinder are integrally formed or are detachably connected;

[0055] Specifically, at least two centering connection blocks are provided and are evenly distributed along the circumferential direction.

[0056] To achieve the above object, the present invention adopts the following technical solutions:

[0057] Application of a device for wax removal or plug flushing in oil well strings in an ESP (Electrical Submersible Pump) oil well string, applying a device for wax removal or plug flushing in an oil well string to an ESP oil well string.

[0058] To achieve the above object, the present invention adopts the following technical solutions:

[0059] Application of a device for wax removal or plug flushing in oil well strings in a piston rod pump oil well string, applying a device for wax removal or plug flushing in an oil well string to a piston rod pump oil well string.

[0060] To achieve the above object, the present invention adopts the following technical solutions:

[0061] A method for using a device for wax removal or plug flushing in an oil well string, comprising the following steps

[0062] S1. Install a device for wax removal or plug flushing in an oil well string above the ESP in the ESP oil well string to replace the check valve or install it below the rod pump to replace the standing valve;

[0063] S2. When the ESP is running or the piston of the rod pump moves upward, the liquid enters the central channel of the lower joint of the device and the through hole of the inner liner seat through the equipment below the device, pushes the inner liner up from the inner liner seat, then passes through the space between the inner wall of the lower housing and the inner liner, and then enters the equipment above the device, and finally reaches the surface process and enters the crude oil gathering and transportation system;

[0064] S3. When the ESP stops running or the piston of the rod pump moves downward and the liquid in the oil well string flows backward downward, at this time, the inner liner ball head tightly presses on the inner liner seat under the action of its own weight and the pressure of the liquid, preventing the upper liquid from passing through the inner liner seat, and the spring cannot be compressed under this pressure, and the valve ball is still held on the valve seat, and the liquid immediately stops flowing downward;

[0065] S4. When the oil well string is blocked, the ESP is blocked or the rod pump is blocked, stop the ESP from running or stop the rod pump from working and lift the piston of the rod pump out of the pump barrel. At this time, the cleaning liquid is pressurized and injected into the oil well string from the ground, enters the device, the valve ball moves downward under the action of the high pressure, pushes the valve support downward, the spring is compressed downward, a flow space appears between the valve ball and the through hole of the valve seat, and the cleaning liquid enters the equipment below the device through the device and then enters the well.

[0066] Further, when the inner wall of the oil well string is blocked by deposited paraffin, replace the cleaning liquid with high-temperature hot water and construct according to step S4.

[0067] In the first embodiment of the present invention, when the centralizing assembly is a centralizing cylinder

[0068] In S2, the liquid flows out from the annulus between the centralizing cylinder and the inner wall of the lower housing, enters the central channel of the upper housing, and then enters the equipment above the device;

[0069] In S4, the cleaning liquid passes through the central channel of the upper housing, the annulus between the outer wall of the lower housing and the centralizing cylinder, and the annulus between the inner wall of the centralizing cylinder and the outer wall of the fixed cylinder on the inner liner, flows into the space above the valve holder through the through hole of the valve seat, then enters the center of the spring from the space above the valve holder through the first liquid channel in the valve holder, and then flows through the through hole of the combination of the inner liner ball head and the lower fixed cylinder and the through hole of the inner liner seat, enters the equipment below the device, and then enters the well.

[0070] In the second embodiment of the present invention, when the centralizing assembly is the upper centralizing ring, the centralizing leg, the lower centralizing ring, and the centralizing connecting block,

[0071] In S2, the liquid flows out from the annulus between the inner liner and the inner wall of the lower housing, enters the central channel of the upper housing, and then enters the equipment above the device;

[0072] In S4, the cleaning liquid passes through the central channel of the upper housing, the central channel of the lower housing, flows into the space above the valve holder through the through hole of the valve seat, then enters the center of the spring from the space above the valve holder through the first liquid channel in the valve holder, and then flows through the through hole of the combination of the inner liner ball head and the lower fixed cylinder and the through hole of the inner liner seat, enters the equipment below the device, and then enters the well.

[0073] In the third embodiment of the present invention, when the centralizing assembly is the lower centralizing ring and the centralizing connecting block,

[0074] In S2, the liquid flows out from the annulus between the inner liner and the lower housing, enters the annulus between the inner liner and the upper housing, and then enters the equipment above the device;

[0075] In S4, the cleaning liquid passes through the central channel of the upper housing, flows into the space above the valve holder through the through hole of the valve seat, then enters the center of the spring from the space above the valve holder through the first liquid channel in the valve holder, and then flows through the through hole of the combination of the inner liner ball head and the lower fixed cylinder and the through hole of the inner liner seat, enters the equipment below the device, and then enters the well.

[0076] The present invention has the following beneficial effects compared with the prior art:

[0077] 1. When the device is in use, the downhole liquid will not pass through the inside of the inner liner. Only when wax removal or blockage removal is carried out on the oil well string and the sucker rod pump, the high-temperature hot water or the cleaning liquid will pass through the inside of the inner liner.

[0078] 2. It can directly pump the cleaning fluid from the wellhead into the oil well string through ground pressurizing equipment. When the string or the sucker rod pump is blocked by debris, it can flush the blockage in the string or the sucker rod pump. When paraffin wax deposits on the inner wall of the oil well string, the cleaning fluid is replaced with high-temperature hot water and pumped into the string to directly contact the paraffin wax on the inner wall of the oil well string, greatly improving the heat transfer efficiency. The high-efficiency heat transfer can accelerate the rapid melting of the paraffin wax deposited on the inner wall of the oil well string, so as to quickly remove it, restore the production of the oil well, reduce the consumption of high-temperature hot water and mechanical costs, reduce the well shut-in time and the costs of paraffin cleaning, well repair and pump repair, and greatly improve the economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0079] Figure 1 FIG. 6 is a schematic structural diagram of Embodiment 1 of an apparatus for paraffin cleaning or flushing blockage in an oil well string according to the present invention;

[0080] Figure 2 FIG. 10 is a schematic structural diagram of Embodiment 2 of an apparatus for paraffin cleaning or flushing blockage in an oil well string according to the present invention;

[0081] Figure 3 FIG. 14 is a schematic structural diagram of Embodiment 3 of an apparatus for paraffin cleaning or flushing blockage in an oil well string according to the present invention;

[0082] Figure 4 FIG. 18 is a schematic structural diagram of the upper housing in Embodiments 1 and 2 of an apparatus for paraffin cleaning or flushing blockage in an oil well string according to the present invention;

[0083] Figure 5 FIG. 22 is a schematic structural diagram of the lower housing in Embodiments 1 and 2 of an apparatus for paraffin cleaning or flushing blockage in an oil well string according to the present invention;

[0084] Figure 6 FIG. 26 is a schematic structural diagram of the inner tank seat of an apparatus for paraffin cleaning or flushing blockage in an oil well string according to the present invention;

[0085] Figure 7 FIG. 30 is a schematic structural diagram of the valve support of an apparatus for paraffin cleaning or flushing blockage in an oil well string according to the present invention;

[0086] Figure 8 FIG. 34 is a schematic structural diagram of the centralizer tube in Embodiment 1 of an apparatus for paraffin cleaning or flushing blockage in an oil well string according to the present invention;

[0087] Figure 9 FIG. 38 is a schematic structural diagram of the lower fixing tube and the inner tank ball head of an apparatus for paraffin cleaning or flushing blockage in an oil well string according to the present invention;

[0088] Figure 10 FIG. 42 is a schematic structural diagram of the upper fixing tube and the valve seat in Embodiment 1 of an apparatus for paraffin cleaning or flushing blockage in an oil well string according to the present invention;

[0089] Figure 11 FIG. Figure 11 is a schematic structural view of an upper fixing cylinder, a valve seat and a centralizing assembly according to Embodiment 2 of a device for wax removal or flushing of blockages in an oil well string of the present invention;

[0090] Figure 12 FIG. Figure 12 is a schematic structural view of an upper fixing cylinder, a valve seat and a centralizing assembly according to Embodiment 3 of a device for wax removal or flushing of blockages in an oil well string of the present invention;

[0091] Figure 13 FIG. Figure 13 is a schematic structural view of an upper housing according to Embodiment 3 of a device for wax removal or flushing of blockages in an oil well string of the present invention;

[0092] Figure 14 FIG. Figure 14 is a schematic structural view of a lower housing according to Embodiment 3 of a device for wax removal or flushing of blockages in an oil well string of the present invention;

[0093] In the figures: 1, upper housing; 2, lower housing; 3, upper and lower housing connection threads; 4, first circular step; 5, second circular step; 6, upper joint; 7, lower joint; 8, inner tank seat; 9, elastic retaining ring; 10, light hole; 11, centralizing cylinder; 12, lower leg ring; 13, plane of the bottom ring of the upper housing; 14, upper leg; 15, inner tank; 16, inner tank ball head; 17, upper top surface; 18, inner top surface; 19, lower leg; 21, lower fixing cylinder; 22, upper fixing cylinder; 23, spring; 24, valve support; 25, valve ball; 26, valve seat; 27, upper and lower fixing cylinder connection threads; 28, inner tank through hole; 29, lower plane; 30, hollow spherical segment; 31, top notch; 32, thread; 33, first liquid channel; 34, lower surface; 35, inner tank seat through hole; 36, upper centralizing ring; 37, centralizing leg; 38, lower centralizing ring; 39, centralizing connection block. Detailed Embodiments

[0094] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0095] Please refer to Figures 1 to 3 , a device for wax removal or flushing of blockages in an oil well string and its application and usage provided by the present invention include an upper housing 1, a lower housing 2, an inner tank seat 8, an inner tank 15, and a centralizing assembly; the upper end of the inner wall of the lower housing 2 is connected to the lower end of the outer wall of the upper housing 1, the inner tank seat 8 is arranged at the lower end of the inner wall of the lower housing 2, the inner tank 15 sits on the inner tank seat 8 when it falls, and the centralizing assembly is sleeved on the inner wall of the lower housing 2 to help the inner tank 15 sit on the inner tank seat 8 smoothly and seal when it falls.

[0096] When it falls, the inner tank 15 is seated on the inner tank seat 8 under the alignment of the alignment component. When it is lifted, the inner tank 15 moves upward under the alignment of the alignment component but does not separate from the device.

[0097] Please refer to Figure 7 , Figure 9 , Figure 10 , the inner tank 15 includes an inner tank ball head 16, a lower fixing cylinder 21, a spring 23, a valve support 24, a valve ball 25, a valve seat 26 and an upper fixing cylinder 22; the inner wall of the lower end of the upper fixing cylinder 22 is provided with upper fixing cylinder connection threads, the outer wall of the lower fixing cylinder 21 is provided with lower fixing cylinder connection threads, and the upper fixing cylinder 22 and the lower fixing cylinder 21 are screwed together through the upper and lower fixing cylinder connection threads 27, and are sealed by thread sealing or adding gaskets.

[0098] The inner tank ball head 16 is arranged at the lower end of the lower fixing cylinder 21. A inner tank through hole 28 with a diameter less than or equal to the inner diameter of the spring 23 is arranged at the center of the inner tank ball head 16. The inner tank ball head 16 can be seated on the inner tank seat through hole 28 for sealing. The spring 23 is placed inside the lower fixing cylinder 21. The inner diameter of the lower fixing cylinder 21 meets the requirements of being a guide sleeve for the spring 23. The lower end of the spring 23 is ground into a plane and contacts the inner bottom surface of the lower fixing cylinder 21. The length of the spring 23 is greater than the lower fixing cylinder 21; the valve support 24 is installed at the upper end of the spring 23. The valve support 24 includes a large cylinder and a small cylinder. The small cylinder is arranged at the lower end of the large cylinder. The outer diameter of the small cylinder is the same as the inner diameter of the spring and is inserted into the center of the spring 23. The lower plane 29 of the large cylinder contacts the upper plane of the spring 23. The lower end surface of the large cylinder of the valve support 24 is above the upper ring surface of the lower fixing cylinder 21. The outer diameter of the large cylinder is less than the inner diameter of the upper fixing cylinder 22, so that the valve support 24 can move up and down inside the upper fixing cylinder 22;

[0099] A first liquid channel 33 is arranged in the valve support 24. There is a hollow spherical segment 30 at the center of the upper surface of the valve support 24. The valve ball 25 is seated in the hollow spherical segment 30. The diameter of the hollow spherical segment 30 is greater than the diameter of the valve ball 25. The valve seat 26 is fixed to the upper end inner wall of the upper fixing cylinder 22. The valve seat 26 and the upper fixing cylinder 22 are screwed together through a thread 32, and are sealed by thread sealing or adding gaskets; a through hole is arranged at the center of the valve seat 26. The valve ball 25 is located between the hollow spherical segment 30 and the valve seat 26. Under normal circumstances, the spring 23 pushes up the valve support 24, and the valve support 24 pushes up the valve ball 25 to make the valve ball 25 seal the through hole of the valve seat 26; there are two semi-deep light holes 10 on the upper surface of the valve seat 26 for cooperating with a special wrench to screw the thread 32.

[0100] As Figure 9 shown, the lower fixing cylinder 21 and the inner tank ball head 16 are integrally formed.

[0101] Please refer to Figure 4 and Figure 5 . The upper housing 1 and the lower housing 2 are both circular hollow structures. The outer wall of the lower end of the upper housing 1 is provided with upper housing connection threads, and the inner wall of the upper end of the lower housing 2 is provided with lower housing connection threads. The upper housing 1 and the lower housing 2 are screwed together through the upper and lower housing connection threads 3, and are sealed by thread sealing or adding gaskets. The upper end of the upper housing 1 is provided with an upper joint 6, and the lower end of the lower housing 2 is provided with a lower joint 7. The inner wall of the upper joint 6 and the outer wall of the lower joint 7 are both provided with oilfield common tubing threads, so as to connect the device to the oil well string.

[0102] Please refer to Figure 5 and Figure 6 . The lower end inner wall of the lower housing 2 is provided with two circular steps, namely the first circular step 4 and the second circular step 5. The second circular step 5 is above the first circular step 4. The inner tank seat 8 is installed on the first circular step 4. An elastic retaining ring 9 is provided on the inner wall of the lower housing 2 close to the upper surface of the inner tank seat 8. The elastic retaining ring 9 is embedded in the inner wall of the lower housing 2 to prevent the inner tank seat 8 from moving up and down. The outer diameter of the inner tank seat 8 is the same as the inner diameter of the lower housing 2 at the contact position. The surfaces of the first circular step 4 and the lower surface 34 of the inner tank seat 8 are both flat and smooth, ensuring good sealing when the surface of the circular step 4 and the lower surface 34 of the inner tank seat 8 are in contact. A through hole 35 of the inner tank seat is provided at the center of the inner tank seat 8.

[0103] The centralizing component is arranged above the second circular step 5.

[0104] Example 1:

[0105] Please view Figure 1 and Figure 8 . The centralizing component is a centralizing cylinder 11; the inner tank 15 is below the upper housing 1.

[0106] The upper end of the centralizing cylinder 11 is provided with upper legs 14 and the lower end is provided with lower legs 12. At least two, preferably three, upper legs 14 and lower legs 12 are provided. The lower end of the lower leg 12 is connected with a lower leg ring 12. The upper end of the centralizing cylinder 11 is closed and the lower end is open.

[0107] Please pay special attention to Figure 1 and refer to Figure 5 and Figure 8 . The lower leg ring 12 sits on the second circular step 5. The upper end surface of the upper leg 14 is below the circular plane 13 at the bottom of the upper housing. The circular plane 13 at the bottom of the upper housing prevents the centralizing cylinder 11 from detaching. The diameters of the circles where the outer edges of the upper legs 14 and the lower legs 19 are located and the outer diameter of the lower leg ring 12 are the same as the inner diameter of the lower housing 2 at their respective positions.

[0108] The upper part of the inner tank 15 is located inside the centering cylinder 11 and is centered by the centering cylinder 11, so that the inner tank 15 cannot tilt at a large angle in the lower outer shell 2. The upper top surface 17 of the inner tank 15 is below the inner top surface 18 of the centering cylinder 11, so that the inner tank 15 can move up and down inside the centering cylinder 11. When moving downward, the inner tank ball head 16 can be seated on the inner tank seat 8 to seal the inner tank seat through hole 35 of the inner tank seat 8. When moving upward, after the upper top surface 17 of the inner tank 15 contacts the inner top surface 18 of the centering cylinder 11, it is blocked and cannot continue to move upward. A second liquid channel is formed between the inner wall of the centering cylinder 11 and the outer wall of the upper fixing cylinder 22 of the inner tank 15, and a third liquid channel is formed between the inner wall of the lower outer shell 2 and the outer wall of the centering cylinder 11.

[0109] At least one top notch 31 is provided on the upper end of the upper fixing cylinder 22 above the upper surface of the valve seat 26 to form a fourth liquid channel.

[0110] Further, in the overall structure of the centering cylinder as shown in Figure 8 , the centering cylinder 11, the lower leg ring 12, the lower legs 19, and the upper legs 14 are combined into an integral structure; the at least two upper legs 14 and the at least two lower legs 19 are evenly distributed along the circumferential direction of the centering cylinder 11.

[0111] Preferably, the lower leg ring 12, the lower legs 19, and the upper legs 14 are integrally formed by casting; preferably, the upper ends of the lower legs 19 are welded to the outer side of the lower part of the centering cylinder 11, and the lower parts are respectively welded to the lower leg ring 12, and the lower ends of the upper legs 14 are welded to the outer side of the upper part of the centering cylinder 11.

[0112] The specific usage method of this embodiment:

[0113] S1. Install the device of the first embodiment above the electric submersible pump in the electric submersible pump oil well string to replace the check valve or install it below the rod pump to replace the fixed valve.

[0114] S2. When the electric submersible pump is running or the rod pump piston is moving upward, the liquid enters the central channel of the lower joint 7 and the inner tank seat through hole 35 of the device through the equipment below the device, jacks up the inner tank 15 from the inner tank seat 8, and the liquid enters the central channel of the upper outer shell 1 from the space between the centering cylinder 11 and the inner wall of the lower outer shell 2, then enters the equipment above the device, and finally reaches the surface process and enters the crude oil gathering and transportation system.

[0115] S3. When the electric submersible pump stops operating or the piston of the rod pump moves downward and the liquid in the oil well string flows backward downward, at this time, under the action of its own weight and the pressure of the liquid, the inner bladder ball head 16 of the inner bladder 15 tightly presses on the inner bladder seat 8, sealing to prevent the liquid in the upper oil well string from flowing downward through the through hole 35 of the inner bladder seat. And under this pressure, the spring 23 below the valve ball 25 cannot reach the pressure that can be compressed, and the valve ball 25 is still held on the valve seat 26 for sealing, and the liquid cannot enter the upper fixed cylinder 22 and the lower fixed cylinder 21 of the inner bladder 15 either. Thus, it cannot flow downward and remains stationary, avoiding the huge impact and damage to the equipment below caused by the rapid downward flow of the liquid when there is no such device.

[0116] S4. When the oil well string is blocked, the electric submersible pump is blocked or the rod pump is blocked, stop the operation of the electric submersible pump or stop the operation of the rod pump and lift the piston of the rod pump out of the pump working barrel. At this time, connect the cleaning liquid to the wellhead process at the upper end of the oil well string from the ground, and use the ground pressurizing equipment to pressurize the cleaning liquid to increase the pressure of the ground cleaning liquid. The pressure is transmitted through the oil well string, the central channel of the upper housing 1, the annulus between the outer wall of the lower housing 2 and the outer wall of the centralizer 11, that is, the third liquid channel, and then through the annulus between the inner wall of the centralizer 11 and the outer wall of the upper fixed cylinder 22 of the inner bladder 15, that is, the second liquid channel, and then through the top notch 31 of the upper fixed cylinder 22, that is, the fourth liquid channel, to transmit the high pressure to the valve ball 25. Under the action of the high pressure, the valve ball 25 moves downward, pushing the valve support 24 downward, compressing the spring 23 downward. A flow space appears between the valve ball 25 and the through hole of the valve seat 26. The liquid flows into the space above the valve support 24 through the through hole of the valve seat 26, and then from the space above the valve support 24 enters the center of the spring 23 through the first liquid channel 33 in the valve support 24, and then flows through the through hole 28 of the combination of the inner bladder ball head 16 and the lower fixed cylinder 21 and the through hole of the inner bladder seat 8, enters the equipment below the device, and then enters the well.

[0117] Embodiment 2:

[0118] Please view Figure 2 、 Figure 11 The centralizer assembly includes an upper centralizer ring 36, centralizer legs 37, a lower centralizer ring 38, and centralizer connection blocks 39; the inner bladder 15 is below the upper housing 1.

[0119] The lower end of the centralizer leg 37 is connected to the outer wall of the upper end of the upper fixed cylinder 22, the upper end of the centralizer leg 37 is connected to the upper centralizer ring 36, and the lower centralizer ring 38 is connected to the outer wall of the upper fixed cylinder through the centralizer connection block 39; at least two centralizer legs 37 are provided and are evenly distributed circumferentially, and at least two centralizer connection blocks 39 are provided and are evenly distributed circumferentially. Preferably, the number of the centralizer legs 37 is three, and the number of the centralizer connection blocks 39 is three.

[0120] The inner tank 15 is located inside the lower outer shell 2 and is centered by the upper centering ring 36 and the lower centering ring 38, so that the inner tank 15 cannot tilt at a large angle in the lower outer shell 2. The upper top surface of the upper centering ring 36 is below the circular ring plane 13 at the bottom of the upper outer shell, enabling the inner tank 15 to move up and down within the lower outer shell 2. When moving downward, the ball head 16 of the inner tank can be seated on the inner tank seat 8, sealing the inner tank seat through-hole 35 of the inner tank seat. When moving upward, after the upper top surface of the upper centering ring 36 contacts the circular ring plane 13 at the bottom of the upper outer shell, it is blocked and cannot continue to move upward.

[0121] Furthermore, the upper centering ring 36, centering legs 37, lower centering ring 38, centering connection block 39, and upper fixing cylinder 22 are an integral body;

[0122] Preferably, the upper centering ring 36, centering legs 37, lower centering ring 38, centering connection block 39, and upper fixing cylinder 22 are integrally formed by casting; preferably, the lower ends of the centering legs 37 are welded to the outer wall of the upper end of the upper fixing cylinder 22, the upper ends of the centering legs 37 are welded to the upper centering ring 36, and the lower centering ring 38 is welded to the upper fixing cylinder 22 through the centering connection block 39.

[0123] The specific usage method of this embodiment:

[0124] S1. Install the device of the second embodiment above the electrical submersible pump in the electrical submersible pump oil well string to replace the check valve or install it below the rod pump to replace the fixed valve;

[0125] S2. When the electrical submersible pump is operating or the piston of the rod pump moves upward, the liquid enters the central channel of the lower joint 7 and the inner tank seat through-hole 35 of the device through the equipment below the device, jacks up the inner tank 15 from the inner tank seat 8, and the liquid flows out from the annulus between the inner tank 15 and the inner wall of the lower outer shell 2, enters the central channel of the upper outer shell 1, then enters the equipment above the device, and finally reaches the surface process and enters the crude oil gathering and transportation system;

[0126] S3. When the electrical submersible pump stops operating or the piston of the rod pump moves downward and the liquid in the oil well string flows backward downward, at this time, under the action of its own weight and the pressure of the liquid, the ball head 16 of the inner tank tightly presses on the inner tank seat 8, sealing and preventing the liquid in the upper oil well string from flowing downward through the inner tank seat through-hole 35. And under this pressure, the spring 23 below the valve ball 25 cannot reach the pressure that can be compressed, and the valve ball 25 is still pressed on the valve seat 26 for sealing, and the liquid cannot enter the upper fixing cylinder 22 and the lower fixing cylinder 21 of the inner tank 15 either, so it cannot flow downward and stops, avoiding the huge impact and damage to the equipment below caused by the rapid downward flow of the liquid without this device;

[0127] S4. When the oil well tubing is blocked, the electric submersible pump is blocked or the rod pump is blocked, the operation of the electric submersible pump is stopped or the rod pump is stopped, and the rod pump piston is lifted out of the pump working cylinder, the cleaning fluid is connected to the wellhead process at the upper end of the oil well tubing from the ground, and the ground pressurizing equipment is used to pressurize the ground cleaning fluid to increase the pressure, and the high pressure is transmitted to the valve ball 25 through the oil well tubing, the central channel of the upper shell 1, and the central channel of the lower shell 2. The valve ball 25 moves downward under the action of the high pressure, pushing the valve support 24 downward, and the spring 23 is compressed downward. A flow space appears between the valve ball 25 and the through hole of the valve seat 26. The liquid flows into the space above the valve support 24 through the through hole of the valve seat 26, and then enters the center of the spring 23 from the space above the valve support 24 through the first liquid channel 33 in the valve support 24, and then flows through the inner liner ball head 16 and the lower fixed cylinder 21 combined with the inner liner through hole 28 and the inner liner seat 8 through hole, enters the equipment below the device, and then enters the well.

[0128] Embodiment 3:

[0129] Please check Figure 3 , Figure 12 , the said straightening assembly is a lower straightening ring 38; the said inner liner 15 extends into the upper outer shell 1;

[0130] The lower centralizing ring 38 is connected to the outer wall of the upper fixed tube 22 via a centralizing connecting block 39. At least two centralizing connecting blocks 39 are provided and evenly distributed in the circumferential direction. Preferably, the number of the centralizing connecting blocks 39 is three.

[0131] The lower part of the inner liner 15 is located inside the lower outer shell 2, and the upper part of the inner liner 15 is located inside the upper outer shell 1. It is straightened by the lower straightening ring 38 and the inner wall of the upper outer shell 1, so that the inner liner 15 cannot be tilted at a large angle in the lower outer shell 2. The lower straightening ring 38 is below the bottom circular ring plane 13 of the upper outer shell, so that the inner liner 15 can move up and down in the lower outer shell 2. When moving downward, the inner liner ball head 16 can be seated on the inner liner seat 8 to seal the inner liner seat through hole 35 of the inner liner seat 8. When moving upward, the upper top surface of the lower straightening ring 38 contacts the bottom circular ring plane 13 of the upper outer shell and is blocked from continuing to move upward.

[0132] Furthermore, the lower straightening ring 38, the straightening connecting block 39, and the upper fixing tube 22 are an integral unit;

[0133] Preferably, the lower righting ring 38 , the righting connection block 39 , and the upper fixed tube 22 are integrally formed by casting; preferably, the lower righting ring 38 and the upper fixed tube 22 are welded together via the righting connection block 39 .

[0134] The specific usage of this embodiment is as follows:

[0135] S1. When the device of the third embodiment is installed in the tubular column of an electric submersible pump oil well to replace the check valve above the electric submersible pump or to replace the fixed valve under the rod pump;

[0136] When the ESP operates or the piston of the rod pump moves upward, the liquid enters the central channel of the lower joint 7 of the device and the through hole 35 of the inner liner seat through the equipment below the device, jacks up the inner liner 15 from the inner liner seat 8, and the liquid flows out from the annulus between the inner liner 15 and the inner wall of the lower housing 2, enters the annulus between the inner liner 15 and the upper housing 1, then enters the equipment above the device, finally reaches the surface process, and enters the crude oil gathering and transportation system;

[0137] S3. When the ESP stops operating or the piston of the rod pump moves downward and the liquid in the oil well string flows backward downward, at this time, under the action of its own weight and the pressure of the liquid, the inner liner ball head 16 of the inner liner 15 tightly presses on the inner liner seat 8, sealing to prevent the liquid in the upper oil well string from flowing downward through the through hole 35 of the inner liner seat. And under this pressure, the spring 23 below the valve ball 25 cannot reach the pressure that can be compressed, and the valve ball 25 is still held on the valve seat 26 for sealing. The liquid cannot enter the upper fixing cylinder 22 and the lower fixing cylinder 21 of the inner liner 15 either, so it cannot flow downward and stops, avoiding the huge impact and damage to the equipment below caused by the rapid downward flow of the liquid without this device;

[0138] S4. When the oil well string is blocked, the ESP is blocked or the rod pump is blocked, the ESP stops operating or the rod pump stops working and the piston of the rod pump is lifted out of the pump barrel. At this time, the cleaning liquid is connected to the wellhead process at the upper end of the oil well string from the ground, and the cleaning liquid is pressurized with the ground pressurizing equipment to increase the pressure of the ground cleaning liquid. The high pressure is transmitted to the valve ball 25 through the oil well string and the central channel of the upper housing 1. The valve ball 25 moves downward under the action of the high pressure, pushes the valve support 24 downward, compresses the spring 23 downward, and a flow space appears between the valve ball 25 and the through hole of the valve seat 26. The liquid flows into the space above the valve support 24 through the through hole of the valve seat 26, then enters the center of the spring 23 from the space above the valve support 24 through the first liquid channel 33 in the valve support 24, and then flows through the inner liner through hole 28 and the through hole of the inner liner seat 8 in the combined body of the inner liner ball head 16 and the lower fixing cylinder 21, enters the equipment below the device, and then enters the well.

[0139] The above three embodiments all achieve creating a space in the oil well string of the oil pump, injecting the cleaning liquid into the oil well string of the oil pump through the ground pressurizing equipment and into the well, so that the cleaning liquid directly flushes the blockage; if paraffin is deposited on the inner wall of the oil well string, replace the cleaning liquid with high-temperature hot water and inject it into the pipe string to directly contact the paraffin on the inner wall of the oil well string, greatly improving the heat transfer efficiency. The high-efficiency heat transfer can accelerate the rapid melting of the paraffin deposited on the inner wall of the oil well string, so as to quickly remove it, restore the production of the oil well, reduce the shut-in time and the costs of paraffin removal, well repair and pump repair, and greatly improve the economic benefits.

[0140] In this application, the components themselves that are not elaborated and the connection methods of the components in this application all belong to the well-known technologies in this technical field. They can be directly applied and will not be elaborated further.

[0141] In the present invention, the term "a plurality of" means two or more, unless otherwise clearly defined. Terms such as "installed", "connected", "coupled", "fixed", etc. should be understood in a broad sense. For example, "connected" can be a fixed connection, a detachable connection, or an integral connection; "coupled" can be a direct coupling or an indirect coupling through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0142] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by terms such as "upper", "lower", "left", "right", "front", "rear", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or unit referred to must have a specific direction, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of the present invention.

[0143] In the description of this specification, the description of terms such as "one embodiment", "some embodiments", "specific embodiments", etc. means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or instance. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0144] The above are only the preferred embodiments of the present invention, and are not intended to limit the present invention. For those skilled in the art, the present invention can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A device for wax removal or flushing of blockages in an oil well string, comprising a housing, characterized in that, It also includes an inner liner seat, an inner liner, and a righting assembly; The inner liner seat is arranged at the lower end of the inner shell, the inner liner is arranged in the outer shell, and sits on the inner liner seat when falling, and the straightening assembly is sleeved in the outer shell, and is used to help the inner liner to sit on the inner liner seat smoothly and seal when falling; The inner container is provided with a spring, a valve core and a valve seat. When the pressure on the valve core is greater than the elastic force of the spring, the spring is compressed and the interior of the inner container is connected.

2. The device for wax removal or flushing of blockages in an oil well string according to claim 1, wherein, The shell comprises an upper shell and a lower shell, the upper end of the lower shell is connected to the lower end of the upper shell, and the inner shell seat is arranged at the lower end of the inner wall of the lower shell.

3. The device for wax removal or flushing of blockages in an oil well string according to claim 2, wherein, The inner liner also includes an inner liner ball head, a lower fixing cylinder, an upper fixing cylinder, and a valve support; The lower part of the upper fixed tube is connected to the outer wall of the lower fixed tube; the inner liner ball head is arranged at the lower end of the lower fixed tube; The center of the inner liner seat is provided with an inner liner seat through hole, and the inner liner ball head can be seated on the inner liner seat through hole for sealing; The spring is placed in the lower fixed cylinder, the valve support is installed on the upper end of the spring, there is a hollow ball notch in the center of the upper surface of the valve support, the valve core sits in the hollow ball notch, and the valve seat is fixed on the upper end of the inner wall of the upper fixed cylinder; Under the action of the spring, the valve core is pressed tightly against the center of the valve seat; The inner wall at the upper end of the lower shell is connected to the outer wall at the lower end of the upper shell, and the lower end of the inner wall of the lower shell is provided with two circular steps, which are divided into a first circular step and a second circular step, and the second circular step is above the first circular step; The inner liner seat is installed on the first circular step, and an elastic retaining ring is provided on the inner wall of the lower shell close to the upper surface of the inner liner seat, and the elastic retaining ring is embedded in the inner wall of the lower shell to prevent the inner liner seat from moving; A straightening assembly is installed above the second circular step.

4. A device for wax removal or flushing of blockages in an oil well string according to claim 3, characterized in that, The outer diameter of the inner liner seat is the same as the inner diameter of the lower shell where it contacts, and the surface of the first circular step and the lower surface of the inner liner seat are both flat and smooth; The upper shell and the lower shell are both circular hollow structures, the upper end of the upper shell is provided with an upper joint, the lower end of the lower shell is provided with a lower joint, and the inner wall of the upper end of the upper joint and the outer wall of the lower end of the lower joint are both provided with oil pipe threads; The inner wall of the lower end of the upper fixing tube is provided with an upper fixing tube connecting thread, and the outer wall of the lower fixing tube is provided with a lower fixing tube connecting thread; The upper fixing tube and the lower fixing tube are screwed together by upper and lower fixing tube connecting threads, and are sealed by threads or with gaskets; The outer wall of the lower end of the upper shell is provided with an upper shell connecting thread, and the inner wall of the upper end of the lower shell is provided with a lower shell connecting thread; The upper shell and the lower shell are screwed together by upper and lower shell connecting threads, and are sealed by threads or with gaskets.

5. A device for wax removal or flushing of blockages in an oil well string according to claim 3, characterized in that, The straightening assembly is a straightening cylinder; the inner liner is below the upper outer shell; The upper end of the straightening cylinder is provided with an upper leg, and the lower end is provided with a lower leg, at least two of the upper legs and the lower legs are provided, and the lower end of the lower leg is connected with a lower leg ring, and the upper end of the straightening cylinder is closed and the lower end is open; The upper part of the inner liner is located inside the straightening cylinder.

6. The device for wax removal or flushing of blockages in an oil well string according to claim 5, characterized in that, The lower leg is seated on the second circular step; The upper end surface of the upper leg is below the circular ring plane at the bottom of the upper shell, and the circular ring plane at the bottom of the upper shell prevents the straightening cylinder from falling off; The diameters of the circles where the outer edges of the upper leg and the lower leg are located and the outer diameter of the lower leg ring are the same as the inner diameter of the lower outer shell at their respective positions; The top surface of the upper part of the inner liner is below the inner top surface of the centering cylinder, enabling the inner liner to move up and down within the centering cylinder. A second liquid channel is formed between the inner wall of the centering cylinder and the outer wall of the upper fixing cylinder of the inner liner, and a third liquid channel is formed between the inner wall of the lower outer shell and the outer wall of the centering cylinder; At least one top notch is provided in the part of the upper end of the upper fixing cylinder above the upper surface of the valve seat; The centering cylinder, the lower leg ring, the lower leg, and the upper leg are integrally formed or are separately connected; The at least two upper legs and the at least two lower legs are evenly distributed along the circumference of the centering cylinder; 7. A device for wax removal or flushing of blockages in an oil well string according to claim 3, characterized in that, The centering assembly includes an upper centering ring, centering legs, a lower centering ring, and centering connection blocks; the inner liner is below the upper outer shell; The lower ends of the centering legs are connected to the outer wall of the upper end of the upper fixing cylinder, the upper ends of the centering legs are connected to the upper centering ring, and the lower centering ring is connected to the outer wall of the upper fixing cylinder through the centering connection blocks; The upper end surface of the upper centering ring is below the circular ring plane at the bottom of the upper outer shell, and the circular ring plane at the bottom of the upper outer shell prevents the inner liner from detaching; The upper centering ring, the centering legs, the lower centering ring, the centering connection blocks, and the upper fixing cylinder are integrally formed or are separately connected; At least two centering legs are provided and are evenly distributed along the circumference, and at least two centering connection blocks are provided and are evenly distributed along the circumference; 8. A device for wax removal or flushing of blockages in an oil well string according to claim 3, characterized in that, The centering assembly is the lower centering ring; the upper part of the inner liner extends into the central flow channel of the upper outer shell; The lower centering ring is connected to the outer wall of the upper fixing cylinder through the centering connection blocks; The upper end surface of the lower centering ring is below the circular ring plane at the bottom of the upper outer shell, and the circular ring plane at the bottom of the upper outer shell prevents the inner liner from detaching; The lower centering ring, the centering connection blocks, and the upper fixing cylinder are integrally formed or are separately connected; At least two centering connection blocks are provided and are evenly distributed along the circumference; 9. A device for wax removal or flushing of blockages in an oil well string according to any one of claims 3-8, characterized in that, The lower fixing cylinder and the inner liner ball head are integrally made, and an inner liner through hole with a diameter less than or equal to the inner diameter of the spring is provided at the center of the inner liner ball head; the valve core is a valve ball, and the diameter of the hollow spherical segment is greater than the diameter of the valve ball; The upper and lower ends of the spring are ground into planes, the lower plane of the spring contacts the inner bottom surface of the lower fixing cylinder, and the lower fixing cylinder serves as a guide sleeve for the spring; The valve support includes a large cylinder and a small cylinder. The small cylinder is arranged at the lower end of the large cylinder. The outer diameter of the small cylinder is the same as the inner diameter of the spring and is inserted into the center of the spring. The lower plane of the large cylinder contacts the upper plane of the spring; the lower end surface of the large cylinder of the valve support is above the upper circular ring plane of the lower fixing cylinder, and the outer diameter of the large cylinder is smaller than the inner diameter of the upper fixing cylinder, enabling the valve support to move up and down within the upper fixing cylinder. A first liquid channel is provided in the valve support; The valve seat and the upper fixing cylinder are screwed together, with thread sealing or gasket sealing; a through hole is provided at the center of the valve seat; auxiliary installation holes are provided on the upper surface of the valve seat; 10. Application of a device for wax removal or flushing of blockages in an oil well string in an electrical submersible pump oil well string, characterized in that, A device for wax removal or flushing of blockages in an oil well string is applied to an ESP oil well string.

11. Application of a device for wax removal or flushing of blockages in a tubing string of a rod-pumped oil well in a piston rod-pumped oil well tubing string, characterized in that, A device for wax removal or flushing of blockages in an oil well string is applied to a piston rod pump oil well string.

12. A method for using a device for wax removal or flushing of blockages in an oil well string, characterized in that, Including the following steps, S1. Install a device for wax removal or flushing blockages in the oil well string above the electric submersible pump in the electric submersible pump oil well string to replace the check valve or install it below the rod pump to replace the fixed valve; S2. When the electric submersible pump is running or the rod pump piston is moving upward, the liquid enters the central channel of the lower joint of the device and the through hole of the inner liner seat through the equipment below the device, lifts the inner liner from the inner liner seat, then passes through the space between the inner wall of the lower housing and the inner liner, and then enters the equipment above the device, and finally reaches the surface process and enters the crude oil gathering and transportation system; S3. When the electric submersible pump stops running or the rod pump piston moves downward and the liquid in the oil well string flows backward downward, at this time, under the action of its own weight and the pressure of the liquid, the inner liner ball head tightly presses on the inner liner seat, preventing the upper liquid from passing through the inner liner seat, and under this pressure, the spring cannot be compressed, and the valve ball is still held on the valve seat, and the liquid immediately stops flowing downward; S4. When the oil well string is blocked, the electric submersible pump is blocked or the rod pump is blocked, stop the operation of the electric submersible pump or stop the rod pump and lift the rod pump piston out of the pump barrel. At this time, pressurize and inject the cleaning liquid from the ground into the oil well string and enter the device. Under the action of the high-pressure, the valve ball moves downward, pushes the valve support downward, the spring is compressed downward, and a flow space appears between the valve ball and the through hole of the valve seat. The cleaning liquid enters the equipment below the device through the device and then enters the well.

13. The usage method of a device for wax removal or flushing of blockages in an oil well string according to claim 12, characterized in that, When the centralizing component is a centralizing cylinder, In S2, the liquid flows out from the annulus between the centralizing cylinder and the inner wall of the lower housing, enters the central channel of the upper housing, and then enters the equipment above the device; In S4, the cleaning liquid passes through the central channel of the upper housing, the annulus between the outer wall of the lower housing and the centralizing cylinder, the annulus between the inner wall of the centralizing cylinder and the outer wall of the fixed cylinder on the inner liner, flows into the space above the valve support through the through hole of the valve seat, then enters the center of the spring from the space above the valve support through the first liquid channel in the valve support, and then flows through the through hole of the combination of the inner liner ball head and the lower fixed cylinder and the through hole of the inner liner seat, enters the equipment below the device, and then enters the well; Or when the centralizing component is an upper centralizing ring, centralizing legs, a lower centralizing ring, and a centralizing connecting block, In S2, the liquid flows out from the annulus between the inner liner and the inner wall of the lower housing, enters the central channel of the upper housing, and then enters the equipment above the device; In S4, the cleaning liquid passes through the central channel of the upper housing, the central channel of the lower housing, flows into the space above the valve support through the through hole of the valve seat, then enters the center of the spring from the space above the valve support through the first liquid channel in the valve support, and then flows through the through hole of the combination of the inner liner ball head and the lower fixed cylinder and the through hole of the inner liner seat, enters the equipment below the device, and then enters the well; Or when the centralizing component is a lower centralizing ring and a centralizing connecting block, In S2, the liquid flows out from the annulus between the inner liner and the lower housing, enters the annulus between the inner liner and the upper housing, and then enters the equipment above the device; In S4, the cleaning liquid passes through the central channel of the upper housing, flows into the space above the valve support through the through hole of the valve seat, then enters the center of the spring from the space above the valve support through the first liquid channel in the valve support, and then flows through the through hole of the combination of the inner liner ball head and the lower fixed cylinder and the through hole of the inner liner seat, enters the equipment below the device, and then enters the well.

14. The method of using a device for wax removal or flushing of blockages in an oil well string according to claim 12, characterized in that, When the inner wall of the oil well string is blocked by deposited paraffin, replace the cleaning liquid with high-temperature hot water and construct according to step S4.

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