Well washing valve and oil well hot washing system

Abstract

The present application relates to oil well hot washing wax technology field, specifically relates to a kind of well washing valve and oil well hot washing system, including valve body, one end of which is provided with liquid inlet, and side wall is provided with the liquid outlet being communicated with liquid inlet;Valve core assembly, be located in the valve body, including for opening and closing the opening and closing member of the liquid inlet, and with opening and closing member interlinkage and for opening and closing the plugging member of liquid outlet, at least a part of the outer periphery of the plugging member and valve body inner wall sealing sliding fit.The present application discards complex multistage hydraulic transmission, realizes the self-adapting characteristics of "high-pressure opening, low-pressure maintenance" of valve by the integrated design of "T type" top rod, high-pressure opening ensures that sealing is reliable during production, avoids false opening, and low-pressure maintenance significantly reduces the system energy consumption when washing well, the design makes power transmission direct, response is rapid, and greatly reduces parts and sealing point from structure, fundamentally improves the reliability and durability of tool.

Description

Technical Field

[0001] This invention relates to the field of hot washing and wax removal technology for oil wells, and particularly to a well washing valve and a hot washing system for oil wells. Background Technology

[0002] In the oil extraction industry, wax buildup on well tubing is a common problem affecting production. As crude oil rises from the high-temperature, high-pressure reservoir to the wellhead, its temperature and pressure continuously decrease. The dissolved wax precipitates and solidifies on the inner wall of the tubing. Severe wax deposition can significantly narrow the oil flow path, increase the load on the pumping unit, and even completely block the tubing, leading to production shutdown. Therefore, regular wax removal operations are essential. The most widely used technique is thermal wax removal by injecting high-temperature washing fluid downhole. Its core lies in how to efficiently transfer heat energy to the wax-covered tubing section.

[0003] Currently, various downhole hot washing valve technologies exist, such as a well-washing valve (CN120556861B) that uses multi-stage hydraulic pressure transmission. Its working principle is as follows: the washing fluid pressure first pushes a sliding sleeve, compressing the hydraulic oil in an independent oil storage chamber. Then, utilizing the incompressible nature of the hydraulic oil, it pushes the piston rod, ultimately opening the valve ball. While this solution achieves the well-washing function, the lengthy force transmission path, involving multiple intermediaries such as the sliding sleeve, hydraulic oil, and piston rod, results in a complex structure and numerous sealing components. This complex structure not only increases the risk of processing and failure but also leads to response lag and energy loss due to multi-stage transmission. Furthermore, the hydraulic oil medium may leak or degrade during long-term use, further affecting its long-term reliability in harsh downhole environments.

[0004] Therefore, there is an urgent need for a new type of well-washing valve with a simpler structure and more direct and efficient force transmission. Summary of the Invention

[0005] In view of this, the purpose of this invention is to provide a well-washing valve and an oil well hot-washing system to solve the above-mentioned technical problems.

[0006] To achieve the above objectives, the present invention provides a well-washing valve, comprising:

[0007] The valve body has an inlet at one end and an outlet on the side wall that connects to the inlet.

[0008] A valve core assembly, disposed within the valve body, includes an opening / closing element for opening and closing the inlet, and a sealing element that is interconnected with the opening / closing element and used for opening and closing the outlet. At least a portion of the outer periphery of the sealing element is in a sealing sliding fit with the inner wall of the valve body. The opening / closing element has a first effective area that withstands fluid pressure when the inlet is closed. The first effective area is smaller than the second effective area on the sealing element that withstands fluid pressure to open the outlet.

[0009] An elastic element is used to provide a bias pressure that causes the plugging element to move upward, so as to simultaneously drive the opening and closing element to block the inlet and the plugging element to block the outlet. During well washing operations, when the fluid pressure applied to the inlet overcomes the bias pressure and pushes open and close the opening and closing element, the fluid can act on the second effective area, thereby enabling the well washing valve to maintain the open state of the outlet at a pressure lower than that required to push open the opening and closing element.

[0010] As a preferred embodiment of the present invention, the opening and closing element is a valve ball, the sealing element is a push rod, the valve body is provided with a ball seat at the liquid inlet, and the valve ball is seated on the ball seat under the action of bias pressure.

[0011] As a preferred embodiment of the present invention, the push rod is T-shaped, comprising an upper thin rod section and a lower thick piston section. The upper end of the thin rod section is used to abut against the valve ball, and the outer periphery of the thick piston section is in a sealing sliding fit with the inner wall of the valve body, and its cross-sectional area constitutes at least a major part of the second effective area.

[0012] As a preferred embodiment of the present invention, an annular groove is provided on the outer periphery of the coarse piston section, and a sealing component is provided in the groove, the sealing component including a rubber ring and / or a piston ring.

[0013] As a preferred embodiment of the present invention, the valve body includes an outer cylinder and an upper connector detachably connected to one end of the outer cylinder, the liquid inlet is located at the upper connector, and the liquid outlet is one or more liquid outlet holes opened on the side wall of the outer cylinder.

[0014] As a preferred embodiment of the present invention, there are multiple liquid outlet holes, which are distributed circumferentially along the outer cylinder.

[0015] As a preferred technical solution of the present invention, the valve body is provided with a limiting structure to limit the maximum stroke of the push rod moving downward. The limiting structure includes a lower plug that is detachably connected to the other end of the outer cylinder. The lower plug is connected to one end of the limiting rod, and the other end of the limiting rod extends toward the thick piston section of the push rod.

[0016] As a preferred embodiment of the present invention, the valve body is internally threaded with an adjusting screw. The adjusting screw abuts against one end of a return spring, which is an elastic element, and the other end of the return spring abuts against the coarse piston section of the push rod. By rotating the adjusting screw, the pre-compression of the return spring can be adjusted, thereby changing the magnitude of the bias force.

[0017] As a preferred embodiment of the present invention, the valve body is further provided with a ball cover, which is a cylindrical shape with openings at both ends. Its axial length covers at least part of the thin rod section of the push rod. A guide channel is formed inside the ball cover, and one end of the guide channel is coaxially connected to the ball seat. The radial dimension of the guide channel gradually decreases from the end away from the ball seat to the connecting end, so as to guide the valve ball to move and accurately sit on the ball seat.

[0018] To better address the aforementioned technical problems, the present invention also provides an oil well hot washing system, comprising an oil pipe, a dual-cylinder sand control pump connected to the bottom of the oil pipe, and any of the aforementioned well washing valves. The well washing valve is connected to the bottom end of the dual-cylinder sand control pump, and its inlet is connected to the gap between the inner and outer cylinders of the dual-cylinder sand control pump.

[0019] The beneficial effects of this invention are:

[0020] 1. Simplified Structure and Fundamentally Improved Reliability: This invention achieves an adaptive pressure characteristic of "high-pressure opening and low-pressure maintenance" for the valve through the integrated design of the "T-shaped" push rod. Firstly, the higher initial opening pressure ensures reliable valve sealing during production, effectively preventing accidental opening. After the valve ball opens, thanks to the structural feature of the push rod's thick piston section being much larger than the valve ball's pressure-bearing area, the well-washing fluid pressure is automatically amplified, allowing the valve to remain fully open with only a significantly reduced maintenance pressure. This substantially reduces the system's continuous workload and equipment energy consumption during well-washing operations. This characteristic stems from the directness of the power transmission path: the well-washing fluid pressure acts directly on the valve ball and push rod piston surface, without any intermediate fluid medium or redundant conversion components, thus offering a significant advantage in rapid response. This integrated design fundamentally reduces the number of valve parts and dynamic sealing points, eliminating the leakage and failure risks common in complex multi-stage transmission systems from the structural source, achieving an overall leap in reliability, economy, and efficiency.

[0021] 2. Rapid response and pressure adaptive characteristics: Due to the direct force transmission path, the valve opens quickly without lag. The unique area difference design requires a higher pressure at the moment of opening to ensure a tight seal, while maintaining a fully open state under significantly reduced pressure after opening. This adaptive pressure characteristic of "high-pressure opening, low-pressure maintenance" ensures that the valve is not accidentally opened during production and reduces the continuous working pressure of the system during well cleaning operations, achieving energy saving and high efficiency.

[0022] 3. Easy maintenance and self-cleaning effect: The overall structure adopts a modular design, making assembly and disassembly simple. The sliding contact between the push rod and the inner wall of the valve body effectively scrapes away any adhering wax or sand particles, creating an auxiliary self-cleaning effect and further enhancing the valve's anti-clogging ability and long-term operational stability under harsh well conditions. Combined with an adjustable elastic element, this valve can flexibly adapt to the pressure requirements of different well depths, making it highly versatile. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only for this invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a schematic diagram of a half-section of the well-washing valve of the present invention;

[0025] Figure 2 For the present invention Figure 1 Enlarged structural diagram at point A in the middle;

[0026] Figure 3 For the present invention Figure 1 Enlarged structural diagram at point B;

[0027] Figure 4 This is a schematic diagram of the structure of the dual-cylinder sand pump of the present invention;

[0028] Figure 5 This is a schematic diagram of the overall assembly structure of the present invention.

[0029] The following are labeled in the diagram: 100, Well-washing valve; 1, Upper connector; 2, Ball seat; 3, Rubber ring; 4, Valve ball; 5, Ball cover; 6, Top rod; 7, Outer cylinder; 8, Limit rod; 9, Return spring; 10, Adjusting screw; 11, Lower plug; 12, Rubber ring; 13, Piston ring; 14, Liquid outlet; 200, Dual-cylinder sand pump; 21, Sucker rod; 22, Plunger; 23, Oil outlet; 24, First valve body; 25, First channel; 26, Second channel; 27, Second valve body; 28, Pump inner cylinder; 29, Pump outer cylinder; 210, Third valve body; 211, Inlet. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments.

[0031] It should be noted that, unless otherwise defined, the technical or scientific terms used in this invention should have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms "first," "second," and similar terms used in this invention do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0032] like Figure 1 , Figure 2 , Figure 3 , Figure 4 and Figure 5 As shown, a well-washing valve includes: a valve body having an inlet at one end and an outlet communicating with the inlet on its side wall; a valve core assembly disposed within the valve body, including an opening / closing element for opening and closing the inlet, and a sealing element that is linked to the opening / closing element and is used to open and close the outlet, at least a portion of the outer periphery of the sealing element being in a sealing sliding fit with the inner wall of the valve body, the opening / closing element having a first effective area (A1) for bearing fluid pressure when the inlet is closed, the first effective area being smaller than a second effective area (A2) on the sealing element for bearing fluid pressure to open the outlet, i.e., A2 > A1; and an elastic element for providing a bias pressure that causes the sealing element to have an upward tendency, so as to simultaneously drive the opening / closing element to block the inlet and the sealing element to block the outlet. During well-washing operations, when the fluid pressure applied to the inlet overcomes the bias pressure and pushes the opening / closing element open, the fluid can act on the second effective area, thereby enabling the well-washing valve 100 to maintain the open state of the outlet at a pressure lower than that required to push the opening / closing element open.

[0033] The above technical solution solves the problems of response delay, large energy loss, complex structure, and low reliability caused by long multi-stage transmission paths and multiple intermediate sealing links in existing technologies. Specifically, this invention constructs an integrated direct hydraulic pressure amplification structure by setting the first effective area of ​​the opening and closing element to be smaller than the second effective area of ​​the sealing element. Its working principle is as follows: during well washing, the pressure initially acts only on area A1, requiring a higher pressure to overcome the initial resistance; once the opening and closing element is opened, the pressure immediately acts simultaneously on the much larger area (A1+A2), generating a huge net thrust, realizing "high-pressure opening and low-pressure maintenance". The high pressure ensures production sealing and prevents accidental opening, while the low-pressure maintenance after opening significantly reduces well washing energy consumption. It has the advantages of direct power transmission, rapid response, extremely simplified structure, and pressure self-adaptation.

[0034] like Figure 1 and Figure 2 As shown, in this embodiment, the opening and closing component is a valve ball 4, the sealing component is a push rod 6, and the valve body is provided with a ball seat 2 at the liquid inlet. The valve ball 4 is seated on the ball seat 2 under the action of bias pressure.

[0035] The above technical solution can solve the risk of delayed force transmission or failure caused by hydraulic oil leakage and component fit clearance in multi-stage transmission. Specifically, during implementation, the valve ball 4 is directly seated on the ball seat 2 under the push of the push rod 6. This is different from the existing technology in which the valve ball and piston rod are separated by intermediate media such as hydraulic oil. Its working principle is that the force transmission path is direct and rigid. In terms of operation, the upward movement of the push rod 6 and the sealing action of the valve ball 4 are synchronized and integrated. The opening and closing response is direct, the action is reliable, and it is more adaptable to complex downhole working conditions.

[0036] like Figure 1 As shown, in this embodiment, the push rod 6 is T-shaped, which includes an upper thin rod section and a lower thick piston section. The upper end of the thin rod section is used to abut against the valve ball 4. The outer periphery of the thick piston section is in a sealing sliding fit with the inner wall of the valve body, and its cross-sectional area constitutes at least the main part of the second effective area.

[0037] Adopting the above technical solution can solve the problems inherent in the split hydraulic amplification structure, such as numerous parts, complex machining and assembly, risk of hydraulic oil leakage, and difficulty in maintenance. Specifically, the T-shaped push rod 6 is the key specific structure for realizing the functions of "area difference (A1 < A2)" and "direct hydraulic pressure amplification". In this specific configuration, the first effective area A1 substantially corresponds to the effective projected area of the valve ball 4承受流体压力的有效投影面积, while the second effective area A2 mainly corresponds to the cross-sectional area of the thick piston section of the push rod 6. The core role of the thin rod section of the push rod 6 is mechanical linkage: when it moves upward, it presses the valve ball 4 tightly against the ball seat 2 to achieve sealing, and when it moves downward, it is driven by the thick piston section. Its working principle is: when the fluid pressure acts on the valve ball 4 (area A1) and overcomes the initial resistance, the fluid then enters below the valve ball 4, and the pressure acts simultaneously on the end face of the much larger thick piston section (area A2), thereby using the same pressure source to generate a significantly amplified thrust to directly drive the same push rod 6. This is fundamentally different from the indirect and multi-stage force transmission method in the closest prior art, which must compress hydraulic oil through an independent sliding sleeve and then push another piston rod through the oil pressure. Integrating the pressure sensing, force amplification, and main motion functions into a single moving component greatly simplifies the system architecture, improves reliability, and reduces costs.

[0038] As Figure 1 and Figure 3 shown, in this embodiment, an annular groove is provided on the outer periphery of the thick piston section, and a sealing component is arranged in the groove. The sealing component includes an O-ring 12 and / or a piston ring 13;

[0039] Adopting the above technical solution can solve the problem of high failure rate of the multi-sealing point system and the risk that the loss of any seal may lead to the loss of the overall function. Specifically, the O-ring 12 and piston ring 13 of the sealing component of the present invention are only used to ensure the dynamic sealing between the thick piston section of the push rod 6 and the inner wall of the valve body. The piston ring 13 provides static and low-pressure dynamic sealing, while the O-ring 12 enhances the sealing performance and wear resistance under high pressure. The combination of the two ensures the sealing reliability of the push rod 6 during reciprocating motion, prevents the internal leakage of the washing fluid, and maintains sufficient hydraulic pressure to push the push rod 6. This dual-sealing structure is suitable for the working environment of high temperature, high pressure, and impurity-containing underground. Compared with the multiple complex and precise dynamic sealing points such as sliding sleeve sealing, oil storage tank sealing, and piston rod sealing that must be set in the prior art to achieve multi-stage transmission, the sealing system of the present invention is greatly simplified. Its working principle is: only by ensuring the sealing of one main moving pair can the core function be realized. The sealing system is simple and reliable, has fewer maintenance points, and is more resistant to wear by impurities in underground fluids.

[0040] As Figure 1 shown, in this embodiment, the valve body includes an outer cylinder 7 and an upper joint 1 detachably connected to one end of the outer cylinder 7. The liquid inlet is arranged on the upper joint 1, and the liquid outlet is one or more liquid outlet holes 14 opened on the side wall of the outer cylinder 7;

[0041] The above technical solution can solve the problems of complex valve body internal flow channels being convoluted, easy to block and difficult to repair. Specifically, the valve body is composed of simple components such as the upper connector 1 and the outer cylinder 7, with a clear structure. The circumferential multi-hole distribution of the liquid outlet 14 ensures smooth liquid drainage. Overall, this simple and modular mechanical structure is in stark contrast to the valve body structure of the prior art that integrates complex control components such as external relief valves and independent hydraulic oil circuits. It has a simple manufacturing process, unobstructed flow channels, is resistant to blockage, and is easy to disassemble and maintain on site.

[0042] like Figure 1 As shown, in this embodiment, there are multiple liquid outlet holes 14, which are distributed along the circumference of the outer cylinder 7. The preferred distribution pattern is that they are arranged in a ring array around the central axis of the outer cylinder 7.

[0043] The above technical solution can further improve the wax carrying and well washing efficiency. Specifically, this porous and uniformly distributed design makes the flow of the well washing fluid more uniform and stable when it is discharged, avoiding vibration or uneven wear that may be caused by single-hole discharge, while enhancing the stirring and replacement effect of the annular fluid around the outer cylinder 7.

[0044] like Figure 1 As shown, in this embodiment, a limiting structure is provided in the valve body to limit the maximum stroke of the push rod 6 moving downward. The limiting structure includes a lower plug 11 that is detachably connected to the other end of the outer cylinder 7. The lower plug 11 is connected to one end of the limiting rod 8, and the other end of the limiting rod 8 extends toward the coarse piston section of the push rod 6.

[0045] The above technical solution can protect the performance stability of the elastic element and ensure that the valve can be accurately reset to the closed position every time. Specifically, when the push rod 6 moves downward, the lower end of the coarse piston section contacts the limit rod 8, which restricts its further downward movement, thereby avoiding excessive compression of the return spring 9 and causing plastic deformation or damage, thus improving the working cycle and reliability of the tool.

[0046] like Figure 1 As shown, in this embodiment, an adjusting screw 10 is threaded inside the valve body. The adjusting screw 10 abuts against one end of the return spring 9, which is an elastic element, and the other end of the return spring 9 abuts against the coarse piston section of the push rod 6. By rotating the adjusting screw 10, the pre-compression of the return spring 9 can be adjusted, thereby changing the magnitude of the bias pressure.

[0047] The above-mentioned technical solution enhances the adaptability and process compatibility of the tool. Specifically, by rotating the adjusting screw 10, the pre-compression of the return spring 9 can be changed, thereby adjusting the magnitude of the first force pushing the push rod 6, i.e., the valve opening pressure. This adjusting mechanism allows the well-washing valve 100 to flexibly set the opening pressure according to different well conditions, different degrees of wax deposition, and well-washing process requirements.

[0048] like Figure 1 and Figure 2 As shown, in this embodiment, a ball cover 5 is also provided in the valve body. The ball cover 5 is a cylindrical shape with open ends. Its axial length covers at least part of the thin rod section of the push rod 6. A guide channel is formed inside the ball cover 5, and one end of it is coaxially connected to the ball seat 2. The radial dimension of the guide channel gradually narrows from the end away from the ball seat 2 to the connection end, so as to guide the valve ball 4 to move and accurately sit on the ball seat 2.

[0049] The above technical solution can solve the problems of jamming and asynchrony that may occur during the reset process of complex systems. Specifically, the ball cover 5 and its tapered guide channel ensure the precise reset of the valve ball 4. This is a significant enhancement to the reliability of the "valve ball-rod" direct mechanical linkage system. Compared to the complex reset path of the valve ball in previous patents, which also relies on multi-stage springs and hydraulic oil, the reset path of this invention is simple, direct, and unique. Its working principle is purely mechanical guidance. The reset action is highly deterministic and the sealing reset accuracy is high, thus ensuring that the valve achieves the best sealing state every time it is closed. In addition, the sliding fit between the push rod 6 and the inner wall of the valve body itself has a self-cleaning effect of scraping off deposits. That is, the side of the push rod 6 can effectively scrape off solid deposits such as wax and sand particles that may adhere to the inner wall of the valve body, forming a continuous self-cleaning effect. This structure not only prevents impurities from depositing on the sealing surface through the inverted fit between the valve ball 4 and the ball seat 2, but also avoids the accumulation of deposits on the inner wall of the flow channel through the scraping action of the push rod 6. This significantly improves the long-term operational reliability and maintenance cycle of the valve in well fluids containing sand and wax, further enhancing the long-term operational reliability.

[0050] like Figure 5 As shown, the present invention also provides an oil well hot washing system, including an oil pipe, a double-cylinder sand control pump 200 connected to the bottom of the oil pipe, and any of the above-mentioned well washing valves 100. The well washing valve 100 is connected to the bottom end of the double-cylinder sand control pump 200, and its inlet is connected to the gap between the inner cylinder 28 and the outer cylinder 29 of the double-cylinder sand control pump 200.

[0051] The above-mentioned technical solution can solve a series of problems existing in prior art and other similar technologies, such as system complexity, low thermal efficiency, multiple failure points, and high maintenance costs. This system combines the highly simplified and reliable well-washing valve 100 of this invention with the dual-cylinder sand control pump 200. Its working principle and operation steps completely abandon the traditional hot washing mode that relies on hollow sucker rods, complex downhole injection valves, and multi-stage hydraulic control transmission, realizing "direct tubing drive" hot washing. The system has high integration, significantly improved hot washing efficiency, and greatly enhanced operation success rate and long-term operational reliability.

[0052] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of the invention is limited to these examples; within the framework of the invention, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of the different aspects of the invention as described above, which are not provided in detail for the sake of brevity.

[0053] This invention aims to cover all such substitutions, modifications, and variations that fall within the scope of protection. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A well wash valve characterized by, include: The valve body has an inlet at one end and an outlet on the side wall that connects to the inlet. A valve core assembly, disposed within the valve body, includes an opening / closing element for opening and closing the inlet, and a sealing element that is interconnected with the opening / closing element and used for opening and closing the outlet. At least a portion of the outer periphery of the sealing element is in a sealing sliding fit with the inner wall of the valve body. The opening / closing element has a first effective area that withstands fluid pressure when the inlet is closed. The first effective area is smaller than the second effective area on the sealing element that withstands fluid pressure to open the outlet. An elastic element is used to provide a bias pressure that causes the plugging element to have an upward tendency, so as to simultaneously drive the opening and closing element to block the inlet and the plugging element to block the outlet. During well washing operation, when the fluid pressure applied to the inlet overcomes the bias pressure and pushes the opening and closing element, the fluid can act on the second effective area, so that the well washing valve can maintain the opening state of the outlet at a pressure lower than that required to push open the opening and closing element. The opening and closing element is a valve ball (4), the plugging element is a push rod (6), and the valve body is provided with a ball seat (2) at the inlet. The valve ball (4) is seated on the ball seat (2) under the action of the bias pressure.

2. The well kill valve of claim 1, wherein, The push rod (6) is T-shaped, comprising a thin rod section at the top and a thick piston section at the bottom. The upper end of the thin rod section is used to abut against the valve ball (4). The outer periphery of the thick piston section is in a sealing sliding fit with the inner wall of the valve body, and its cross-sectional area constitutes at least the main part of the second effective area.

3. The well wash valve of claim 2, wherein, The outer periphery of the coarse piston section is provided with an annular groove, and a sealing assembly is provided in the groove. The sealing assembly includes a rubber ring (12) and / or a piston ring (13).

4. The well wash valve of claim 1, wherein, The valve body includes an outer cylinder (7) and an upper connector (1) detachably connected to one end of the outer cylinder (7). The liquid inlet is located at the upper connector (1), and the liquid outlet is one or more liquid outlet holes (14) opened on the side wall of the outer cylinder (7).

5. The well wash valve of claim 4, wherein, There are multiple outlet holes (14), which are distributed circumferentially along the outer cylinder (7).

6. The well wash valve of claim 2, wherein, The valve body is provided with a limiting structure to limit the maximum stroke of the push rod (6) downward. The limiting structure includes a lower plug (11) that is detachably connected to the other end of the outer cylinder (7). The lower plug (11) is connected to one end of the limiting rod (8), and the other end of the limiting rod (8) extends toward the coarse piston section of the push rod (6).

7. The well wash valve of claim 2, wherein, The valve body is internally threaded with an adjusting screw (10). The adjusting screw (10) abuts against one end of a return spring (9) which is an elastic element. The other end of the return spring (9) abuts against the coarse piston section of the push rod (6). By rotating the adjusting screw (10), the pre-compression of the return spring (9) can be adjusted, thereby changing the magnitude of the bias pressure.

8. The well wash valve of claim 2, wherein, The valve body is also provided with a ball cover (5), which is a cylindrical shape with open ends. Its axial length covers at least part of the thin rod section of the push rod (6). A guide channel is formed inside the ball cover (5), and one end of it is coaxially connected to the ball seat (2). The radial dimension of the guide channel gradually decreases from the end away from the ball seat (2) to the connecting end, so as to guide the valve ball (4) to move and accurately sit on the ball seat (2).

9. An oil well hot wash system characterized by, The device includes an oil pipe, a dual-cylinder sand control pump (200) connected to the bottom of the oil pipe, and a well-washing valve (100) as described in any one of claims 1 to 8, wherein the well-washing valve (100) is connected to the bottom end of the dual-cylinder sand control pump (200), and its inlet communicates with the gap between the inner cylinder (28) and the outer cylinder (29) of the dual-cylinder sand control pump (200).

Images