Overflow-preventing well device for forward and reverse washing

Abstract

The present application relates to the technical field of downhole operation of petroleum industry, and particularly relates to a kind of anti-overflow positive and negative well washing device.The anti-overflow positive and negative well washing device comprises a cylinder for connecting with a pipe column, the cylinder extends along the up-down direction, a valve cylinder extending along the up-down direction is arranged in the cylinder, an annular channel with an open upper end and a closed lower end is formed between the valve cylinder and the cylinder, a communication channel is arranged on the cylinder wall of the valve cylinder and communicates the annular channel and the inner cavity of the valve cylinder;the lower end of the valve cylinder is provided with an inner ring table, a compression spring and a valve seat reciprocally movable along the up-down direction are arranged in the valve cylinder, the valve seat has a valve seat channel penetrating along the up-down direction, the compression spring is above the valve seat to apply downward pressure to the valve seat, and in turn the valve seat presses on the inner ring table;the cylinder is provided with a support structure below the valve cylinder, and a valve ball is supported on the support structure.The anti-overflow positive and negative well washing device can realize oil well positive and negative well washing operation at the same time when realizing anti-overflow.

Description

Technical Field

[0001] This invention relates to the field of downhole operation technology in the petroleum industry, specifically to an anti-overflow forward and reverse well washing device. Background Technology

[0002] During oilfield workover operations, the process of pulling in and out drill string frequently results in workover fluid spillage and environmental pollution. There are two main reasons for this: First, the problem of wet-pulling the drill string during tripping. Specifically, workover tools are connected to the bottom of the drill string for operations such as retrieval and milling. When retrieval tools retrieve blocked debris, a circulation channel cannot be established between the inside and outside of the drill string. Therefore, during tripping, the drill string is often wet-pulled. When the drill string threads are disconnected, the workover fluid inside the drill string sprays out instantly from the bottom, causing turbulent flow and environmental pollution. Second, the problem of water gushing from the top of the drill string during descent. Specifically, a drill pipe stand is generally composed of two drill pipes connected together by threads, with a total length of approximately 19.2 meters. The drill pipe stand is hoisted by the traveling block hook and lowered into the well one by one after the threaded connection. The wellbore is typically filled with workover fluid. When the top of each drill pipe stand is 3-5 meters below the drill platform, workover fluid will spray out or overflow from the top of the drill pipe. This phenomenon is mainly caused by the drill pipe volume occupying the casing volume; the amount of workover fluid overflowing is equal to the volume of the drill pipe that has been lowered. The overflowing workover fluid is discharged through the drill pipe's internal channels and the annular space between the casing and the drill pipe. When a large-diameter tool (6-8 mm smaller than the casing's inner diameter) is lowered, the flow area of ​​the annular space between the casing and the drill pipe is smaller than the flow area inside the drill pipe. This results in less workover fluid flowing out of the annular space and more flowing out of the drill pipe's internal channels. When the drill pipe is lowered rapidly, the workover fluid will spray out or overflow from the top of the drill pipe. Well fluid flowing out of the casing can be guided to the sewage discharge device through the venting manifold to avoid environmental pollution; however, well workover fluid that sprays out or overflows from the top of the drill pipe cannot be recovered because it falls from a height, which will cause environmental pollution, waste of well workover fluid, and harm to the health of employees.

[0003] Chinese utility model patent CN204941452U discloses an impact-type oil drain. In use, the impact-type oil drain is connected to the bottom of the pump. When the hollow shear pin is sheared by impact, the inner cavity of the drain body connects to the outside of the pipe, achieving the purpose of oil draining and solving the aforementioned problem of wet tubing. However, the above-mentioned oil drain cannot solve the problem of workover fluid spraying out or overflowing from the top of the drill pipe during drilling.

[0004] Chinese utility model patent CN210858638U discloses a downhole tubing string and its blowout preventer. In use, the blowout preventer's connecting end is connected to the lower end of the corresponding tubing in the downhole tubing string. The blowout preventer is lowered into the well along with the tubing string. During the lowering process, a flow restrictor reduces the flow rate of well fluid per unit time, thereby extending the time it takes for the lower section of the tubing to fill the upper section. However, the aforementioned downhole tubing string and its blowout preventer have the following problems: 1) The flow restrictor is not completely sealed during the blowout prevention process, and overflow can still occur in the tubing after a long time; 2) The flow restrictor is made of paraffin wax, which melts into the well fluid and cannot be reused.

[0005] Chinese utility model patent CN206111137U discloses a blowout preventer (BOP) check valve. In practical use, the upper end of the connecting coupling connects to the wellbore string, and the lower end connects to the wellbore tool. The valve ball inside the valve cylinder is fixed in the valve seat under the action of the valve stem and return spring, blocking the through hole in the valve seat and sealing the flow passage in the wellbore, thus achieving blowout prevention during the running-in and running-out of the wellbore. Although the above-mentioned BOP check valve can solve the problem of blowout prevention for the running-in wellbore, it has the following problems: 1) After the BOP check valve is run to a certain depth in the well, because the tubing above the BOP check valve is hollow inside and filled with well fluid outside, there is a large pressure difference between the inside and outside of the tubing at deeper locations in the well, which can damage the tubing threads; 2) It can only achieve forward well washing operations, but cannot achieve reverse well washing operations. Summary of the Invention

[0006] The purpose of this invention is to provide an anti-overflow forward and reverse well washing device to solve the technical problem that the existing blowout preventer check valve cannot simultaneously perform forward and reverse well washing operations when achieving anti-overflow.

[0007] To achieve the above objectives, the technical solution of the anti-overflow forward and reverse well washing device of the present invention is as follows:

[0008] An anti-overflow forward and reverse well washing device includes a cylindrical body for connection with a tubing string. The cylindrical body extends vertically, and a valve cylinder extending vertically is provided inside the cylindrical body. An annular channel with an open upper end and a closed lower end is formed between the valve cylinder and the cylindrical body. A connecting channel is provided on the cylinder wall of the valve cylinder, connecting the annular channel and the inner cavity of the valve cylinder. An inner annular platform is provided at the lower end of the valve cylinder. A compression spring and a valve seat that can reciprocate vertically are provided inside the valve cylinder. The valve seat has a valve seat channel that runs vertically. The compression spring is located above the valve seat to apply downward pressure to the valve seat, thereby causing the valve seat to press against the inner annular platform. A support structure is provided inside the cylindrical body below the valve cylinder, and a valve ball is supported on the support structure.

[0009] The beneficial effects are as follows: In use, the device of the present invention is connected to the tubing string. During forward well washing, the valve ball is supported on the support structure under the pressure of the forward well washing fluid to open the valve seat channel, thereby allowing the well fluid to flow downwards through the annular channel, the connecting channel, and the valve seat channel to achieve forward circulation well washing. When the tubing string is lowered, the valve ball moves upwards under the force of the well fluid and enters the inner annular platform, sealing and engaging with the valve seat to block the valve seat channel, thus preventing the well fluid below the valve tube from flowing upwards, thereby achieving the effect of preventing overflow. During reverse well washing, the valve ball moves upwards under the pressure of the reverse well washing fluid and enters the inner annular platform, engaging with the valve seat to push it, thereby separating the valve seat from the inner annular platform, allowing the well fluid below the valve tube to flow upwards through the gap between the valve seat and the inner annular platform, the connecting channel, and the annular channel to achieve reverse circulation well washing.

[0010] As a further improvement, the upper end of the valve cylinder is provided with an adjusting seat for adjusting the preload of the compression spring, the upper end of the compression spring pressing against the adjusting seat, and the lower end of the compression spring pressing against the valve seat.

[0011] The beneficial effect is that the preload of the pressure spring can be adjusted by adjusting the adjusting seat to adapt to different well conditions.

[0012] As a further improvement, the adjusting seat is provided with an adjusting seat channel that runs through the vertical direction.

[0013] The beneficial effect is that by setting an adjustment seat channel on the adjustment seat, the flow area during forward and reverse well washing can be increased, thereby improving the working efficiency of forward and reverse well washing.

[0014] As a further improvement, the adjusting seat is threaded onto the upper end of the valve cylinder.

[0015] The beneficial effect is that the preload of the compression spring can be infinitely adjusted by rotating the adjusting seat.

[0016] As a further improvement, the connecting channel is a long strip-shaped channel extending in the vertical direction.

[0017] The beneficial effect is that this design facilitates the processing of connecting channels.

[0018] As a further improvement, at least two of the communication channels are arranged at circumferential intervals along the valve cylinder.

[0019] The beneficial effect is that this design can increase the flow area and improve the construction efficiency of forward and reverse well washing.

[0020] As a further improvement, the cylinder includes an upper cylinder and a lower cylinder, with the inner side of the lower end of the upper cylinder threadedly connected to the outer side of the upper end of the lower cylinder, and the outer side of the lower end of the valve cylinder threadedly connected to the inner side of the upper end of the lower cylinder.

[0021] The beneficial effect is that this design makes it easier to disassemble and assemble the valve cylinder.

[0022] As a further improvement, the support structure is a support rib, and the maximum distance between the support rib and the inner wall surface of the cylinder is less than the diameter of the valve ball.

[0023] The beneficial effects are: the supporting horizontal ribs are relatively simple and facilitate the flow of well fluid inside the cylinder.

[0024] As a further improvement, the valve ball is a nylon ball.

[0025] The beneficial effect is that the nylon ball is lighter and can easily move upward under the force of the well fluid when the tubing is lowered.

[0026] As a further improvement, hollow shear pins are provided on the cylinder wall above the valve cylinder.

[0027] The beneficial effect is that when the inside and outside of the downhole tubing cannot be connected, the hollow shear pin can be broken by striking and cutting with a drop bar to connect the inside and outside of the tubing, thus avoiding the problem of wet tubing being pulled out during the tripping process. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the overflow prevention forward and reverse well washing device of the present invention in forward well washing or when stationary;

[0029] Figure 2 This is a schematic diagram of the anti-overflow forward and reverse well washing device of the present invention during the running of the tubing string;

[0030] Figure 3 This is a schematic diagram of the overflow prevention forward and reverse well washing device of the present invention during reverse well washing;

[0031] Figure 4 for Figure 1 Schematic diagram of the middle and lower cylinder;

[0032] Figure 5 for Figure 1 Schematic diagram of the central valve assembly;

[0033] Figure 6 for Figure 1 Schematic diagram of the hollow shear stud;

[0034] In the diagram: 11. Upper cylinder; 12. Annular channel; 13. Valve seat channel; 14. Lower cylinder; 15. Hollow shear pin; 16. Adjusting seat; 17. Compression spring; 18. Valve cylinder; 19. Connecting channel; 20. Valve seat; 21. Valve ball; 22. Support rib; 23. Adjusting seat channel; 24. Outer annular platform; 25. Inner annular platform; 26. Threaded section; 27. Annular groove; 28. Smooth rod section; 29. ​​Blind hole. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only for explaining the invention and are not intended to limit the invention; that is, the described embodiments are merely some embodiments of the invention, not all embodiments. The components of the embodiments of the invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0036] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0037] It should be noted that relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any actual relationship or order between these entities or operations. Furthermore, terms such as "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element. Additionally, the terms "front," "rear," "upper," "lower," "left," and "right" are based on the orientation and positional relationships shown in the accompanying drawings and are used only for the convenience of describing the invention, not to indicate that the referred device or component must have a specific orientation, and therefore should not be construed as limiting the invention.

[0038] The features and performance of the present invention will be further described in detail below with reference to embodiments.

[0039] Example 1 of the overflow prevention forward and reverse well washing device of the present invention:

[0040] like Figure 1 As shown, the overflow prevention reverse well washing device includes a cylindrical body for connection to the tubing string, the cylindrical body extending vertically, and a valve assembly housed within the cylindrical body. The cylindrical body includes an upper cylindrical body 11 and a lower cylindrical body 14, the inner side of the lower end of the upper cylindrical body 11 being threadedly connected to the outer side of the upper end of the lower cylindrical body 14. In other embodiments, the cylindrical body is a one-piece structure.

[0041] like Figure 5As shown, the valve assembly includes a valve cylinder 18 that extends in the vertical direction. The lower end of the valve cylinder 18 is provided with an outer ring platform 24 and an inner ring platform 25. The outer ring platform 24 is threadedly connected to the inner side of the upper end of the lower cylinder 14 to fix the valve cylinder 18 on the lower cylinder 14.

[0042] In this embodiment, an annular channel 12, open at the top and closed at the bottom, is formed between the valve cylinder 18 and the upper cylinder 11. A connecting channel 19, which connects the annular channel 12 and the inner cavity of the valve cylinder 18, is provided on the cylinder wall of the valve cylinder 18. The connecting channel 19 is an elongated channel extending in the vertical direction, and four connecting channels 19 are arranged at intervals along the circumference of the valve cylinder 18 to increase the flow area. In other embodiments, the number of connecting channels 19 can be set as needed.

[0043] In this embodiment, an adjusting seat 16, a compression spring 17, and a valve seat 20 are arranged sequentially from top to bottom inside the valve cylinder 18. The upper end of the compression spring 17 presses against the adjusting seat 16, and the lower end of the compression spring 17 presses against the valve seat 20. The adjusting seat 16 is threadedly connected to the valve cylinder 18 to adjust the preload of the compression spring 17. The valve seat 20 can reciprocate in the vertical direction, and the compression spring 17 applies a downward elastic force to the valve seat 20 so that the valve seat 20 presses against the inner ring platform 25. The adjusting seat 16 has an adjusting seat channel 23 that extends vertically, and the valve seat 20 has a valve seat channel 13 that extends vertically.

[0044] like Figure 1 and Figure 4 As shown, a supporting transverse rib 22 is provided inside the lower cylinder 14 below the valve assembly. The supporting transverse rib 22 is located in the middle of the lower cylinder 14, so that the flow passage of the lower cylinder 14 at the supporting transverse rib 22 is two semicircles. A valve ball 21 is supported on the supporting transverse rib 22. The radius of the semicircle is smaller than the diameter of the valve ball 21. The valve ball 21 is supported on the inner wall of the lower cylinder 14 on one side in the horizontal direction. The supporting transverse rib 22 constitutes a supporting structure.

[0045] In this embodiment, the valve ball 21 is a nylon ball to ensure that it can move upward under the impact force of the well fluid and make sealing contact with the valve seat 20.

[0046] In this embodiment, a hollow shear pin 15 is provided on the cylinder wall of the upper cylinder 11 above the valve assembly, such as... Figure 6As shown, the hollow scissor bolt 1 has a blind hole 29, which communicates with the outside of the upper cylinder 11. The hollow scissor bolt 15 includes a threaded section 26 and a smooth section 28, with an annular groove 27 between the threaded section 26 and the smooth section 28. The hollow scissor bolt 15 is threadedly connected to the cylinder wall of the upper cylinder 11 through the threaded section 26 to achieve fixation. Because the wall thickness at the annular groove 27 is relatively thin, the hollow scissor bolt 15 will break off from the annular groove 27 under the action of external force, thus connecting the inside and outside of the upper cylinder 11. The hollow scissor bolt 15 is made of copper to facilitate its breakage.

[0047] In use, the device of the present invention is connected to the drill string, such as... Figure 1 As shown, the valve ball 21 is supported on the support rib 22 under the action of gravity, and the valve seat channel 13 is in the open state at this time. When the drill pipe string is lowered, the device is in the lowering motion state, as shown. Figure 2 As shown, the valve ball 21 moves upward into the inner ring platform 25 after being subjected to the reaction force of the well fluid, and seals with the valve seat 20 to block the valve body passage 13. Since the reaction force of the well fluid is less than the pressure of the compression spring 17 when the drill string is lowered, the valve seat 20 cannot move upward. Therefore, when the drill string is lowered, the well fluid cannot enter the drill string through the device of this invention, thus achieving the effect of preventing overflow.

[0048] It should be noted that as the device descends deeper into the well, the pressure difference between the inside and outside of the drill string increases. Under the action of the pressure difference, the valve ball 21 pushes against the valve seat 20 to separate the valve seat 20 from the inner annular platform 25. At this time, part of the well fluid flows upward to the valve cylinder 18 through the gap between the valve seat 20 and the inner annular platform 25, the connecting channel 19, and the annular channel 12. Another part of the well fluid flows upward to the valve cylinder 18 through the gap between the valve seat 20 and the inner annular platform 25, the connecting channel 19, and the adjusting seat channel 23, so as to reduce the pressure difference between the inside and outside of the drill string and avoid damage to the drill string threads caused by the pressure difference. After the pressure difference decreases, under the action of the compression spring 17, the valve seat 20 pushes against the inner annular platform 25 again, preventing the well fluid from entering the drill string.

[0049] When the drill string stops descending, the device of the present invention also stops descending, such as... Figure 1 As shown, the valve ball 21 falls back onto the support rib 22 by its own weight, the valve seat channel 13 opens, and part of the well fluid flows upward into the drill pipe through the valve seat channel 13, the connecting channel 19 and the annular channel 12, while another part of the well fluid flows upward into the drill string through the valve seat channel 13 and the adjusting seat channel 23, so that the fluid level between the drill string and the casing is balanced.

[0050] When the well is being cleaned, such as Figure 1As shown, the valve ball 21 is supported on the support rib 22 under the pressure of the positive well washing fluid to open the valve seat passage 13; part of the well fluid flows down to the valve cylinder 18 through the annular passage 12, the connecting passage 19 and the valve seat passage 13, and another part of the well fluid flows down to the valve cylinder 18 through the regulating seat passage 23 and the valve seat passage 13 to achieve positive circulation well washing.

[0051] During backwashing, the valve ball 21 moves upward under the pressure of the backwash fluid, entering the inner annular platform 25 and engaging with the valve seat 20. Because the pressure of the backwash fluid is greater than the pressure of the compression spring 17, the valve ball 21 and valve seat 20 together compress the compression spring 17 and move upward, causing the valve seat 20 to separate from the inner annular platform 25. Figure 3 As shown. At this time, a portion of the well fluid flows upward to the valve cylinder 18 through the gap between the valve seat 20 and the inner ring platform 25, the connecting channel 19, and the annular channel 12, while another portion of the well fluid flows upward to the valve cylinder 18 through the gap between the valve seat 20 and the inner ring platform 25, the connecting channel 19, and the regulating seat channel 23, so as to achieve reverse circulation well washing.

[0052] When the workover tool retrieves a fallen object, and the drill string cannot be connected due to blockage inside the object or blockage in the tool's water passage, a drop bar is dropped from the top of the drill string. Under the action of gravity and acceleration, the drop bar impacts and shears the hollow shear pin 15, thereby connecting the inside and outside of the drill string.

[0053] Example 2 of the anti-overflow forward and reverse well washing device of the present invention:

[0054] The difference between this embodiment and Embodiment 1 is that in Embodiment 1, the upper end of the compression spring presses against the adjusting seat, and the lower end of the compression spring presses against the valve seat. In this embodiment, a sealing plate is welded to the upper end of the valve cylinder, the upper end of the compression spring presses against the sealing plate, and the lower end of the compression spring presses against the valve seat. In other embodiments, the sealing plate can be integrally formed on the valve cylinder.

[0055] Example 3 of the overflow prevention and reversing well washing device of the present invention:

[0056] The difference between this embodiment and Embodiment 1 is that in Embodiment 1, the adjusting seat has an adjusting seat channel running vertically through it. In this embodiment, the adjusting seat is a plug, meaning that the adjusting seat does not have an adjusting seat channel.

[0057] Example 4 of the anti-overflow forward and reverse well washing device of the present invention:

[0058] The difference between this embodiment and Embodiment 1 is that in Embodiment 1, the adjusting seat is threadedly connected to the upper end of the valve cylinder. In this embodiment, the adjusting seat can slide vertically within the valve cylinder, and after sliding into position, it is fixed inside the valve cylinder by a set screw.

[0059] Example 5 of the anti-overflow forward and reverse well washing device of the present invention:

[0060] The difference between this embodiment and Embodiment 1 is that in Embodiment 1, the connecting channel is a long strip extending in the vertical direction. In this embodiment, the connecting channel is a circular channel or a rectangular channel.

[0061] Example 6 of the anti-overflow forward and reverse well washing device of the present invention:

[0062] The difference between this embodiment and Embodiment 1 is that in Embodiment 1, the supporting structure is a supporting horizontal rib, and the maximum distance between the supporting horizontal rib and the inner wall surface of the cylinder is less than the diameter of the valve ball. In this embodiment, the supporting structure is a supporting mesh plate.

[0063] Example 7 of the overflow prevention and reverse well washing device of the present invention:

[0064] The difference between this embodiment and Embodiment 1 is that in Embodiment 1, the valve ball was a nylon ball, while in this embodiment, the valve ball is a hollow steel ball.

[0065] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. The scope of patent protection of the present invention shall be determined by the claims. Similarly, any equivalent structural changes made based on the description and drawings of the present invention shall also be included within the scope of protection of the present invention.

Claims

1. An overflow prevention and reversible well-washing device, characterized in that, The device includes a cylindrical body for connection to a tubing column, extending vertically. A valve cylinder extending vertically is housed within the cylindrical body. The cylindrical body comprises an upper cylindrical body and a lower cylindrical body. The inner lower end of the upper cylindrical body is threadedly connected to the outer upper end of the lower cylindrical body. The outer lower end of the valve cylinder is threadedly connected to the inner upper end of the lower cylindrical body, forming an annular channel between the valve cylinder and the cylindrical body, open at the top and closed at the bottom. The valve cylinder wall has a connecting channel between the annular channel and the valve cylinder's inner cavity. The lower end of the valve cylinder has an inner annular platform. A compression spring and a valve seat reciprocating vertically are housed within the valve cylinder. The valve seat has a valve seat channel extending vertically, and the compression spring is located on the upper part of the valve seat. A downward pressure is applied to the valve seat, causing it to press against the inner annular platform. The upper end of the valve cylinder is provided with an adjusting seat for adjusting the preload of the compression spring. The upper end of the compression spring presses against the adjusting seat, and the lower end of the spring presses against the valve seat. The adjusting seat has an adjusting seat channel running vertically through it. The connecting channel is a long, narrow channel extending vertically, radially connecting to the lower part of the annular channel, with its lower end extending to the inner annular platform. The length of the long, narrow channel is greater than the height of the valve seat. A support structure is provided inside the cylinder below the valve cylinder, supporting a valve ball. Hollow shear pins are provided on the cylinder wall above the valve cylinder.

2. The overflow prevention and reversible well washing device according to claim 1, characterized in that, The adjusting seat is threadedly connected to the upper end of the valve cylinder.

3. The overflow prevention and reverse well washing device according to any one of claims 1 to 2, characterized in that, The connecting channels are arranged at least two intervals along the circumference of the valve cylinder.

4. The overflow prevention and reversible well-washing device according to any one of claims 1 to 2, characterized in that, The supporting structure is a horizontal support rib, and the maximum distance between the horizontal support rib and the inner wall surface of the cylinder is less than the diameter of the valve ball.

5. The overflow prevention and reversible well-washing device according to any one of claims 1 to 2, characterized in that, The valve ball is a nylon ball.

6. The overflow prevention and reversible well-washing device according to any one of claims 1 to 2, characterized in that, The hollow shear pin has a blind hole communicating with the outside. The hollow shear pin includes a threaded section that is threaded to the cylinder and a smooth rod section located inside the cylinder. An annular groove is provided between the threaded section and the smooth rod section.

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