Well washing device

Abstract

The utility model belongs to the field of borehole cleaning devices, and particularly relates to a well cleaning device. In order to reduce accidents caused by failure of a spring of the well washing device, the utility model provides the well washing device. The well washing device comprises an inner pipe, an outer pipe, a piston and an upper connector, a first pressure transmitting hole is formed in the inner pipe, a radial through hole is formed in the part, located below the inner pipe, of the outer pipe, and the piston comprises a pressure bearing part located between the inner pipe and the outer pipe and a switch part located below the inner pipe. A first pressure transmitting cavity only communicated with the first pressure transmitting hole is defined between the pressure bearing part and the inner pipe, an upper ball seat is arranged on the part, located below the first pressure transmitting hole, of the inner pipe, a lower ball seat is arranged on the switch part, and the inner diameter of the lower ball seat is smaller than that of the upper ball seat; in the moving stroke of the piston, the piston is provided with an upper station used for opening the radial through hole and a lower station used for blocking the radial through hole. A spring is omitted, and the piston moves through the soluble ball and the ball seat, so that a well washing channel is opened or closed, and the accident rate is reduced.

Description

Technical Field

[0001] This utility model belongs to the field of devices for cleaning wells, and in particular relates to a well cleaning device. Background Technology

[0002] In the process of oilfield development, forward and reverse well washing are required, which necessitates the use of appropriate tools.

[0003] For example, Chinese utility model patent CN217652711U, with authorization announcement date of October 25, 2022, discloses an oil-casing injection well-washing device and an oil-casing injection tubing string. The oil-casing injection well-washing device includes an inner tube, an outer tube, an upper connector connecting the inner and outer tubes, an annular well-washing valve, and a spring. In use, firstly, a drop ball is inserted into the oil-casing injection well-washing device, which is then seated on the ball seat of the annular well-washing valve (equivalent to a sliding sleeve). Then, pressure is applied from the wellhead into the tubing, causing the annular well-washing valve to move downwards, connecting the inside and outside of the oil-casing injection well-washing device, thus enabling direct well-washing. During the downward movement of the annular well-washing valve, the spring is compressed; after the direct well-washing is completed, the annular well-washing valve returns to its original position under the action of the spring, separating the inner and outer spaces of the oil-casing injection well-washing device.

[0004] For example, Chinese utility model patent CN202249949U, with an authorization announcement date of May 30, 2012, discloses an externally pressure-operated reverse circulation valve. In use, pressure is applied to the annulus, acting on the piston head and pushing it (equivalent to a sliding sleeve) downwards to connect the inside and outside of the reverse circulation valve, thus enabling backwashing. During the downward movement of the piston head, the spring is compressed; after backwashing is complete, the piston head returns to its original position under the action of the spring, separating the inner and outer spaces of the reverse circulation valve.

[0005] All of the above tools include springs. During long-term use, the springs may fail due to corrosion, causing the corresponding annular well-washing valve or piston head to fail to reset, thus failing to separate the internal space of the tubing and the annulus, and consequently making it impossible to continue production.

[0006] In the stratified water injection process, water needs to be injected into the formation through an injection switch. During water injection, the pressure in the annulus increases. For the backwash valve, under normal circumstances, the spring force can prevent the piston head from moving downward; when the spring fails, the piston head will move downward abnormally, thus making it impossible to continue the water injection operation. Utility Model Content

[0007] The purpose of this invention is to provide a well-washing device to solve the technical problem of accidents caused by the failure of springs in existing tools.

[0008] To achieve the above objectives, the technical solution of the well-washing device provided by this utility model is as follows:

[0009] A well-washing device includes an inner tube, an outer tube, a piston, and an upper connector for connecting the inner tube and the outer tube. The piston is located inside the outer tube. The inner tube is provided with a first pressure-transmitting hole communicating with the internal channel of the inner tube. The portion of the outer tube located below the inner tube is provided with a radial through hole. The piston includes a pressure-bearing portion located between the inner tube and the outer tube and a switching portion located below the inner tube.

[0010] The pressure-bearing part and the inner tube form a first pressure-transmitting cavity that communicates only with the first pressure-transmitting hole. The part of the inner tube below the first pressure-transmitting hole is provided with an upper ball seat, and the switch part is provided with a lower ball seat. The inner diameter of the lower ball seat is smaller than the inner diameter of the upper ball seat.

[0011] During the piston's active stroke: the piston has an upper position for opening the radial through hole and a lower position for sealing the radial through hole.

[0012] Furthermore, the switch part is provided with a second pressure transmission hole that communicates with the internal channel of the piston. The top of the pressure-bearing part, the inner tube, the outer tube and the upper connector together form a second pressure transmission chamber that communicates only with the second pressure transmission hole. The lower ball seat is located on the part of the switch part below the second pressure transmission hole.

[0013] Furthermore, the piston includes a first small diameter section and a first large diameter section located below the first small diameter section. The first large diameter section is in a movable sealing fit with the outer tube to block the radial through hole when the piston is in the lower position. The first small diameter section is in a clearance fit with the outer tube to form a pressure transmission channel. The second pressure transmission hole is provided on the first small diameter section, and the pressure transmission channel connects the second pressure transmission chamber and the second pressure transmission hole.

[0014] Furthermore, the piston includes an upper sub-piston and a lower sub-piston. The lower end of the upper sub-piston is fixedly connected to the upper end of the lower sub-piston. The upper sub-piston portion is located between the inner tube and the outer tube to form the pressure-bearing portion. The lower sub-piston is located below the inner tube and forms the switching portion.

[0015] Furthermore, the lower end of the upper piston has an internal thread, and the upper end of the upper piston has an external thread, with the upper piston and the lower piston being threadedly connected.

[0016] Furthermore, the outer tube is provided with a limiting step to restrict the piston's downward extreme position. When the piston is engaged with the limiting step, the piston is in the lower working position.

[0017] Furthermore, the lower end of the outer tube is provided with an internal thread.

[0018] Furthermore, the switch section is provided with a stop step, and the lower end face of the inner tube forms a limiting surface for limiting the piston's upward extreme position. When the stop step and the limiting surface stop and cooperate, the piston is in the upper working position.

[0019] Furthermore, the inner tube includes a second small diameter section and a second large diameter section located below the second small diameter section. The pressure-bearing part includes a first part that seals with the second small diameter section and a second part that seals with the second large diameter section. The first part, the second part, the second small diameter section, and the second large diameter section together form the first pressure-transmitting cavity. The transition between the first part and the second part forms a stepped surface for bearing pressure.

[0020] Furthermore, the upper end of the outer tube is provided with an internal thread, the upper end of the inner tube is provided with an external thread, and the lower end of the upper connector is provided with both internal and external threads. The upper connector is threadedly connected to both the inner and outer tubes.

[0021] The beneficial effects of the well-washing device provided by this utility model are as follows: This utility model is an improved invention. The core difference between this utility model and the prior art is that this utility model does not include a spring, and therefore there is no problem caused by the corrosion of the spring.

[0022] To facilitate understanding by those skilled in the art, the beneficial effects of this utility model well-washing device are described in detail below in conjunction with specific usage processes.

[0023] To open the well-washing passage, firstly, a large-diameter soluble ball is dropped into the tubing from the wellhead, and the ball is seated on the upper ball seat. Then, pressure is applied into the tubing, and hydraulic pressure enters the first pressure transmission chamber through the first pressure transmission hole and pushes the piston upward, so that the piston switches to the upper position. At this time, the radial through hole is opened. Finally, wait for the large-diameter soluble ball to dissolve. After the large-diameter soluble ball is dissolved, the well-washing passage is opened.

[0024] It should be noted that since the well-washing device does not include a spring, the piston will not automatically return to its original position. Therefore, after the well-washing channel is opened, forward and / or reverse well washing can be performed according to the actual situation.

[0025] When resuming production after well washing, firstly, drop a small-diameter soluble ball into the tubing from the wellhead. The small-diameter soluble ball will then be seated on the lower ball seat. Next, pressurize the tubing. The small-diameter soluble ball will push the piston downward and switch to the lower working position. At this time, the radial through hole will be blocked and the well washing channel will be closed. Finally, wait for the small-diameter soluble ball to dissolve. Once the small-diameter soluble ball has dissolved, normal production can resume.

[0026] Since the well-washing device of this utility model does not include springs, accidents caused by spring failure will not occur, which helps to reduce the accident rate. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the well-washing device of this utility model when it is closed;

[0028] Figure 2This is a schematic diagram of the well-washing device of this utility model when it is turned on.

[0029] Explanation of reference numerals in the attached figures:

[0030] 1. Upper connector; 2. Outer tube; 3. Inner tube; 4. Upper pressure chamber; 5. Upper piston; 6. Sealing ring; 7. Upper pressure hole; 8. Lower pressure chamber; 9. Upper ball seat; 10. Lower piston; 11. Pressure transmission channel; 12. Lower pressure hole; 13. Lower ball seat; 14. Radial through hole; 15. Limiting step. Detailed Implementation

[0031] To address the problems in the background technology, the core inventive concept of this utility model is as follows: eliminating the spring, and using a soluble ball, an upper ball seat, and a lower ball seat to achieve piston movement. When the piston is to move upward to open the well washing channel, a large-diameter soluble ball that can be seated on the upper ball seat is placed, and hydraulic pressure enters the pressure transmission chamber through the pressure transmission hole to push the piston upward; when the piston is to move downward to close the well washing channel, a small-diameter soluble ball that can be seated on the lower ball seat is placed, and the small-diameter soluble ball pushes the piston downward.

[0032] The present invention will be further described in detail below with reference to embodiments of the well washing device.

[0033] like Figures 1-2 As shown, in a basic specific implementation, the well-washing device includes an inner tube 3, an outer tube 2, a piston, and an upper connector 1 for connecting the inner tube 3 and the outer tube 2. The piston is located inside the outer tube 2. The inner tube 3 is provided with a first pressure-transmitting hole (hereinafter referred to as the upper pressure-transmitting hole 7) that communicates with the internal channel of the inner tube 3. The portion of the outer tube 2 located below the inner tube 3 is provided with a radial through hole 14. The piston includes a pressure-bearing portion located between the inner tube 3 and the outer tube 2 and a switching portion located below the inner tube 3. The pressure-bearing portion and the inner tube 3 form a first pressure-transmitting chamber (hereinafter referred to as the lower pressure-transmitting chamber 8) that communicates only with the upper pressure-transmitting hole 7. The portion of the inner tube 3 located below the upper pressure-transmitting hole 7 is provided with an upper ball seat 9, and the switching portion is provided with a lower ball seat 13. The inner diameter of the lower ball seat 13 is smaller than the inner diameter of the upper ball seat 9. During the piston's active stroke: the piston has an upper position for opening the radial through hole 14 and a lower position for sealing the radial through hole 14.

[0034] Preferably, in Figures 1-2 In the embodiment shown, the upper connector 1 is used to connect to the upper oil pipe. The upper end of the outer pipe 2 is provided with an internal thread, the upper end of the inner pipe 3 is provided with an external thread, and the lower end of the upper connector 1 is provided with both internal and external threads. The upper connector 1 is threadedly connected to both the inner pipe 3 and the outer pipe 2. The structure is simple and the installation is convenient.

[0035] In other embodiments, the outer tube 2, the inner tube 3, and the upper connector 1 can also be fixedly connected by welding or other methods.

[0036] To facilitate understanding by those skilled in the art, the beneficial effects of this utility model well-washing device are described in detail below in conjunction with specific usage processes.

[0037] To open the well-washing passage, firstly, a large-diameter soluble ball is dropped into the tubing from the wellhead, and the large-diameter soluble ball is seated on the upper ball seat 9; then, pressure is applied into the tubing, and the hydraulic pressure enters the lower pressure transmission chamber 8 through the upper pressure transmission hole 7 and pushes the piston upward, so that the piston switches to the upper working position. At this time, the radial through hole 14 is opened; finally, wait for the large-diameter soluble ball to dissolve. After the large-diameter soluble ball is dissolved, the well-washing passage is opened.

[0038] It should be noted that since the well-washing device does not include a spring, the piston will not automatically return to its original position. Therefore, after the well-washing channel is opened, forward and / or reverse well washing can be performed according to the actual situation.

[0039] When resuming production after well washing, firstly, drop a small-diameter soluble ball into the tubing from the wellhead. The small-diameter soluble ball will be seated on the lower ball seat 13. Then, pressurize the tubing. The small-diameter soluble ball will push the piston downward and switch to the lower working position. At this time, the radial through hole 14 will be blocked and the well washing channel will be closed. Finally, wait for the small-diameter soluble ball to dissolve. Normal production can be resumed after the small-diameter soluble ball has dissolved.

[0040] Since this well-washing device does not include a spring, accidents caused by spring failure will not occur, thus reducing the accident rate. Furthermore, the device is simple to operate; simply insert soluble balls of different sizes and then apply pressure from the wellhead to activate or deactivate it.

[0041] In the above embodiment, when the piston moves upward and downward, the volume of the sealed chamber enclosed by the piston, outer tube 2, inner tube 3, and upper connector 1 changes. When the piston moves downward, the volume of the sealed chamber increases, and the pressure inside the sealed chamber decreases; when the piston moves upward, the volume of the sealed chamber decreases, and the pressure inside the sealed chamber increases, which is unfavorable for the piston's upward and downward movement. At this time, the sealed chamber is a dead space.

[0042] In order to enable the piston to move upward and downward more effectively, in a preferred embodiment, such as Figures 1-2 As shown, the switch part is provided with a second pressure transmission hole (hereinafter referred to as the lower pressure transmission hole 12) that communicates with the internal channel of the piston. The top of the pressure-bearing part, the inner tube 3, the outer tube 2, and the upper connector 1 together form a second pressure transmission chamber (hereinafter referred to as the upper pressure transmission chamber 4) that communicates only with the lower pressure transmission hole 12. The lower ball seat 13 is located on the part of the switch part below the lower pressure transmission hole 12. At this time, the upper pressure transmission chamber 4 is not a dead chamber.

[0043] When the piston moves upward, the liquid in the upper pressure chamber 4 is discharged through the lower pressure transmission hole 12; when the piston moves downward, the liquid enters the upper pressure chamber 4 through the lower pressure transmission hole 12, which is beneficial for the piston to move upward and downward.

[0044] Similarly, when the piston moves upward, the high-pressure liquid enters the lower pressure transmission chamber 8 to push the piston; when the piston moves downward, the liquid in the lower pressure transmission chamber 8 is discharged through the upper pressure transmission hole 7, which is beneficial for the piston to move upward and downward. That is, the lower pressure transmission chamber 8 is not a dead chamber.

[0045] It should be noted that when the high-pressure liquid enters the upper pressure chamber 4 through the lower pressure transmission hole 12, the high-pressure liquid can also help push the piston downward. At this time, the upper end face of the piston forms a pressure bearing surface.

[0046] To simplify the structure, in a preferred embodiment, such as Figures 1-2 As shown, the piston includes a first small diameter section and a first large diameter section located below the first small diameter section. The first large diameter section is in a movable sealing fit with the outer tube 2 to block the radial through hole 14 when the piston is in the lower position. The first small diameter section is in a clearance fit with the outer tube 2 to form a pressure transmission channel 11. The lower pressure transmission hole 12 is provided on the first small diameter section, and the pressure transmission channel 11 connects the upper pressure chamber 4 and the lower pressure transmission hole 12. The structure is simple, and the pressure transmission channel 11 is an annular channel with a large flow area.

[0047] In other embodiments, a groove extending to the upper surface is machined on the outer peripheral surface of the piston, and the groove communicates with the lower pressure transmission hole 12 to form the pressure transmission channel 11; or, a blind hole communicating with the lower pressure transmission hole 12 is machined on the upper surface of the piston, and the blind hole constitutes the pressure transmission channel 11.

[0048] exist Figures 1-2 In the embodiment shown, the piston includes an upper sub-piston 5 and a lower sub-piston 10. The lower end of the upper sub-piston 5 is fixedly connected to the upper end of the lower sub-piston 5. The upper sub-piston 5 is located between the inner tube 3 and the outer tube 2 to form the pressure-bearing part. The lower sub-piston 10 is located below the inner tube 3 and forms the switching part, which is convenient for processing and manufacturing.

[0049] The lower part of the lower piston 10 forms the first large diameter section, and the upper part of the lower piston 10 and the upper piston 5 together form the first small diameter section.

[0050] In other embodiments, the piston can also be manufactured as a single piece using casting or 3D printing technology.

[0051] In a preferred embodiment, the lower end of the upper piston 5 has an internal thread, and the upper end of the upper piston 5 has an external thread. The upper piston 5 and the lower piston 10 are threaded together for easy assembly.

[0052] In other embodiments, the upper piston 5 and the lower piston 10 can also be fixedly connected by welding or other methods.

[0053] To facilitate limiting the extreme positions of the piston's downward movement, in a preferred embodiment, such as... Figures 1-2 As shown, the outer tube 2 is provided with a limiting step 15 for limiting the piston's downward extreme position. When the piston is stopped by the limiting step 15, the piston is in the lower working position.

[0054] Preferably, in one embodiment, the lower end of the outer tube 2 is provided with an internal thread, through which an adapter short section can be connected, thereby connecting to the lower oil pipe.

[0055] In other embodiments, the lower end of the outer tube 2 is reduced in diameter to form a smaller diameter section, and the outer circumferential surface of the smaller diameter section is provided with external threads to form a lower connector, which is used to connect to the lower oil pipe.

[0056] exist Figures 1-2 In the illustrated embodiment, the inner tube 3 includes a second small-diameter section and a second large-diameter section located below the second small-diameter section. The pressure-bearing portion includes a first part that seals with the second small-diameter section and a second part that seals with the second large-diameter section. The first part, the second part, the second small-diameter section, and the second large-diameter section together form the lower pressure transmission chamber 8. The transition between the first part and the second part forms a stepped surface for bearing pressure. At this time, the liquid pressure in the lower pressure transmission chamber 8 acts upward on the stepped surface and downward on the transition between the second small-diameter section and the second large-diameter section. Therefore, the area of ​​the piston subjected to the upward force is greater than the area subjected to the downward force, so the piston can move upward under the action of liquid pressure.

[0057] As the piston moves downward, the stepped surface can engage with the stop at the transition between the second small diameter section and the second large diameter section to limit the piston's downward movement to its extreme position.

[0058] In other embodiments, the structure in which the inner tube 3 and the piston form the lower pressure transmission chamber 8 can also adopt the structure in the prior art that forms the pressure transmission chamber so that the piston can move upward. The essence is that the area of ​​the piston subjected to the upward force is greater than the area subjected to the downward force. This part is not an improvement of this utility model and will not be described in detail here.

[0059] exist Figures 1-2 In the embodiment shown, when the piston moves upward, the piston engages with the lower end face stop of the upper connector 1 to limit the extreme position of the piston's upward movement.

[0060] In other embodiments, refer to Figures 1-2 As shown, the switch part is provided with a stop step, and the lower end face of the inner tube 3 forms a limiting surface for limiting the piston's upward extreme position. When the stop step and the limiting surface stop together, the piston is in the upper working position.

[0061] The upper end face of the lower piston 10 forms the stop step, or the stop step is protruding on the inner surface of the switch part.

[0062] When the limiting step 15 and the limiting surface are used to limit the piston's downward and upward extreme positions, the lower pressure transmission chamber 8 and the upper pressure transmission chamber 4 can always maintain a certain volume, which facilitates the entry of liquid into the corresponding pressure transmission chamber.

[0063] It should be noted that a sealing ring 6 can also be installed between the piston and the inner tube 3. Figures 1-2 In the middle, sealing rings 6 are provided on both the upper and lower sides of the lower pressure transmission chamber 8; similarly, sealing rings 6 can also be provided between the piston and the outer tube 2, such as... Figure 1 As shown, when the piston is in the lower position, sealing rings 6 are provided on both the upper and lower sides of the radial through hole 14.

[0064] Finally, it should be noted that the above are merely preferred embodiments of this utility model and are not intended to limit the utility model. Although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments without creative effort, or make equivalent substitutions for some technical features, or organically combine different specific implementation methods to create the specific implementation methods shown in the accompanying drawings. Of course, those skilled in the art can also create other specific implementation methods not shown in the accompanying drawings. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A well-washing device, comprising an inner tube, an outer tube, a piston, and an upper connector for connecting the inner tube and the outer tube, wherein the piston is located inside the outer tube, characterized in that, The inner tube is provided with a first pressure-transmitting hole that communicates with the internal channel of the inner tube, and the outer tube is provided with a radial through hole in the part below the inner tube. The piston includes a pressure-bearing part located between the inner tube and the outer tube and a switching part located below the inner tube. The pressure-bearing part and the inner tube form a first pressure-transmitting cavity that communicates only with the first pressure-transmitting hole. The part of the inner tube below the first pressure-transmitting hole is provided with an upper ball seat, and the switch part is provided with a lower ball seat. The inner diameter of the lower ball seat is smaller than the inner diameter of the upper ball seat. During the piston's active stroke: the piston has an upper position for opening the radial through hole and a lower position for sealing the radial through hole.

2. The well-washing device as described in claim 1, characterized in that, The switch part is provided with a second pressure transmission hole that communicates with the internal channel of the piston. The top of the pressure bearing part, the inner tube, the outer tube and the upper connector together form a second pressure transmission chamber that communicates only with the second pressure transmission hole. The lower ball seat is located on the part of the switch part below the second pressure transmission hole.

3. The well-washing device as described in claim 2, characterized in that, The piston includes a first small diameter section and a first large diameter section located below the first small diameter section. The first large diameter section is in a movable sealing fit with the outer tube to block the radial through hole when the piston is in the lower position. The first small diameter section is in a clearance fit with the outer tube to form a pressure transmission channel. The second pressure transmission hole is provided on the first small diameter section, and the pressure transmission channel connects the second pressure transmission chamber and the second pressure transmission hole.

4. The well-washing device according to any one of claims 1 to 3, characterized in that, The piston includes an upper sub-piston and a lower sub-piston. The lower end of the upper sub-piston is fixedly connected to the upper end of the lower sub-piston. The upper sub-piston is located between the inner tube and the outer tube to form the pressure-bearing part. The lower sub-piston is located below the inner tube and forms the switching part.

5. The well-washing device as described in claim 4, characterized in that, The lower end of the upper piston has an internal thread, and the upper end of the upper piston has an external thread. The upper piston and the lower piston are threaded together.

6. The well-washing device according to any one of claims 1 to 3, characterized in that, The outer tube is equipped with a limiting step to restrict the piston's downward extreme position. When the piston is engaged with the limiting step, the piston is in the lower working position.

7. The well-washing device as described in claim 5, characterized in that, The lower end of the outer tube is threaded.

8. The well-washing device according to any one of claims 1 to 3, characterized in that, The switch section is equipped with a stop step, and the lower end face of the inner tube forms a limiting surface for limiting the piston's upward extreme position. When the stop step and the limiting surface stop and cooperate, the piston is in the upper working position.

9. The well-washing device according to any one of claims 1 to 3, characterized in that, The inner tube includes a second small diameter section and a second large diameter section located below the second small diameter section. The pressure-bearing part includes a first part that seals with the second small diameter section and a second part that seals with the second large diameter section. The first part, the second part, the second small diameter section and the second large diameter section together form the first pressure-transmitting cavity. The transition between the first part and the second part forms a stepped surface for bearing pressure.

10. The well-washing device according to any one of claims 1 to 3, characterized in that, The upper end of the outer tube is provided with an internal thread, the upper end of the inner tube is provided with an external thread, and the lower end of the upper connector is provided with both internal and external threads. The upper connector is threadedly connected to both the inner and outer tubes.

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