Underground flow control opening and closing nipple

Abstract

The utility model relates to an underground flow control opening and closing short section, and belongs to the field of petroleum and natural gas exploitation. Comprising an upper joint, an outer shell and a lower joint, the upper piston and the lower piston can move up and down; the rigid spring and the weak spring push the upper piston and the lower piston to return; the pin, the pin sliding groove, the soluble bottom and the soluble circular ring are used for controlling the rebound stroke of the upper piston; the vertical movement of the upper piston and the lower piston can be controlled by changing the flow of a well mouth, the movement distance of the upper piston is controlled through the pin and the pin sliding groove, and then opening and closing of a short section channel are controlled; and operations such as fracturing, exploiting and salvaging in the oil and gas exploiting process can be effectively simplified.

Description

Technical Field

[0001] The utility model belongs to the field of oil and natural gas exploitation, in particular to an underground flow control opening and closing short joint. Background Art

[0002] During oil extraction, large-volume flushing of the fish head is required for salvage and well repair operations, and the channel must be kept unobstructed. Some hydraulic well repair tools require high-pressure fluid as a drive, and the channel must be kept closed. Ball throwing is used to hold the pressure. If the tubing is stuck, the balls will block the internal channel of the tubing, and subsequent cutting tools cannot be lowered. Dissolvable balls are used, but the dissolution cycle is long, and some well repair tools have small diameters, so the balls are small in size, making it difficult for the balls to pass through some joints, ultimately leading to long well repair time and high costs.

[0003] A downhole flow control opening and closing nipple is mainly used to open and close the flow control channel. When closed, the main force is on the lower joint, which can withstand greater pressure; when opened, the throttling pressure difference can be used to push the upper and lower pistons downward, and the pump can be stopped to move upward. Due to the action of the pin, the piston strokes are different and the channel is closed; if the tubing is stuck, the soluble bottom is dissolved. Due to the small dissolution volume and short dissolution cycle, the diameter is increased, and the tubing can be cut by a cutting tool. Summary of the Invention

[0004] To achieve the above-mentioned purpose, the present application proposes a downhole flow control opening and closing short joint, comprising an upper joint, an outer shell, and a lower joint extending in the axial direction; the upper joint is connected to the outer shell by a threaded connection; the outer shell is slidably connected to the upper piston; the interior of the upper piston is through-through, and a boss extending outwards on the top is provided, which is connected to a rigid spring, and extends into the interior of the lower piston below; the rigid spring is placed in the upper cavity formed by the upper joint, the upper piston, and the outer shell, and the rigid spring is sleeved on the outside of the upper piston, with the upper side of the rigid spring in contact with the upper piston and the lower side in contact with the outer shell; the top of the lower piston is provided with a boss extending outwards, which is connected to a weak spring, and the lower piston is placed in the lower joint and slidably connected to the lower joint.

[0005] The lower joint is connected to the outer shell through threads, and a weak spring is placed inside.

[0006] The weak spring is placed in the lower cavity formed by the outer shell, the lower joint and the lower piston. The weak spring is sleeved on the outer surface of the lower piston. The upper side of the weak spring contacts the lower piston and the lower side contacts the lower joint.

[0007] The upper piston is through-connected, with an outward protruding platform on the top, a related pin slide groove in the middle, and a soluble bottom fixed at the bottom to seal the internal channel of the upper piston. A flow hole is opened on the side of the bottom of the upper piston; the soluble bottom can control its dissolution.

[0008] A pin hole is provided in the middle of the outer shell.

[0009] The pin can pass through the pin hole in the middle of the outer shell and move in a fixed direction in the pin slide groove, and the pin can stop at a special point.

[0010] The points include normally open points, throttling dead points, normally closed points, and pressurized points. Different numbers of throttling dead points and normally closed points can be configured according to actual work requirements.

[0011] The top of the lower piston is provided with an outward protrusion, and the bottom is penetrated by a stepped hole.

[0012] A soluble ring is fixed on the last small hole of the stepped hole to reduce the diameter of the lower piston.

[0013] The soluble ring and the soluble bottom are made of a light and high-strength soluble alloy material and will dissolve when exposed to special chemical agents.

[0014] Preferably, the stiffness coefficient of the weak spring is smaller than that of the rigid spring.

[0015] Preferably, the total area of ​​the flow holes is smaller than the inner hole area of ​​the soluble ring at the bottom of the lower piston.

[0016] Compared with the prior art, the utility model has the following advantages:

[0017] 1. The user can control the flow of the wellhead mud pump according to the working conditions, and then control the opening and closing of the downhole channel. It can be opened and closed repeatedly without pulling out the pipe string;

[0018] 2. No need to pitch, simple operation;

[0019] 3. Different needs can be met by configuring different points;

[0020] 4. The dissolution of the soluble bottom and the soluble ring can be controlled to increase the diameter, making it convenient for other salvage tools to pass through. It is small in size and has a fast dissolution speed. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 A cross-sectional view of the initial position of the downhole flow control opening and closing sub;

[0022] Figure 2 The upper piston surface morphology

[0023] Figure 3 This is the radial expansion diagram of the pin slide;

[0024] Figure 4 This is a cross-sectional view of a downhole flow control opening and closing sub with the pin located at the throttling dead point;

[0025] Figure 5 This is a cross-sectional view of a downhole flow control opening and closing sub with the pin located at the normally closed point;

[0026] Figure 6This is a cross-sectional view of a downhole flow control opening and closing sub with the pin located at the pressurization point;

[0027] Figure 7 It is a cross-sectional view of the soluble ring and the soluble bottom after dissolution;

[0028] Figure 8 This is the radial expansion diagram of the pin slide after changing the special point position of the pin slide.

[0029] In the accompanying drawings, the list of components represented by each reference numeral is as follows: 1-upper joint, 2-upper cavity, 3-upper piston, 4-rigid spring, 5-outer shell, 6-pin, 7-lower cavity, 8-lower piston, 9-weak spring, 10-lower joint, 11-soluble ring, 12-soluble bottom, 301-pin slide groove, 302-flow hole, 501-pin hole, a-normally open point, b-throttling dead point, c-normally closed point, d-pressurization point. DETAILED DESCRIPTION

[0030] like Figure 1 , Figure 2 , Figure 3 As shown, a downhole flow control opening and closing short joint is used. When in operation, the device is connected to the rest of the pipe string through the upper and lower drill pipe connecting threads. The initial state remains normally open. A pin slide groove 301 is opened on the outer surface of the upper piston 3, and a flow hole 302 is opened on the side of the bottom; the pin slide groove 301 is provided with a normally open point a, a throttling dead point b, a normally closed point c, and a pressurization point d.

[0031] like Figure 4 As shown, when the pump is turned on and circulated, the flow rate gradually increases, and the fluid flows into the lower piston 8 through the side hole of the upper piston 3, and then flows into the lower pipe column through the bottom of the lower piston 8. As the fluid channel becomes narrower, the fluid will push the upper piston 3 and the lower piston 8 to move downward; and due to the difference in stiffness between the rigid spring 4 and the weak spring 9, the throttling pressure required for the lower piston 8 to move downward is less than that of the upper piston 3, so the lower piston 8 moves downward first until the bottom of the lower piston 8 contacts the lower joint 10; at the same time, during the downward movement of the upper piston 3, the pin 6 moves from the normally open point a of the upper piston 3 to the throttling dead point b, limiting the downward movement of the upper piston 3.

[0032] like Figure 5 As shown, turn off the pump and stop pumping fluid. The upper piston 3 and the lower piston 8 move upward due to the action of the spring, and the pin 6 moves from the throttling dead point b of the upper piston 3 to the normally closed point c. The lower piston 8 returns to its initial position. Due to the action of the pin 6, the rebound distance of the upper piston 3 is small, so the side through hole of the upper piston 3 is blocked by the step below the lower piston 8, and the channel is closed.

[0033] like Figure 6As shown, when the upper string requires a higher pressure to work, the pump is turned on to increase pressure. Since the small hole on the side of the upper piston 3 is closed, the pressure pushes the upper piston 3 downward. When the bottom of the upper piston 3 contacts the bottom of the lower piston 8, the upper and lower pistons 8 are pushed downward until the lower piston 8 contacts the lower joint 10, and the pin 6 moves from the normally closed point c to the pressure point d.

[0034] When the pressure is released, the spring pushes the upper and lower pistons 8 upward, and the pin 6 moves from the pressurized point d to the normally open point a, the channel opens, and the device returns to its initial state.

[0035] like Figure 7 As shown, if the pipe string is stuck and a tool needs to be lowered to the stuck point to release the jam, a special agent can be injected to dissolve the soluble bottom 12 and the soluble ring 11, so that the bottom of the upper piston 3 and the lower piston 8 are unblocked and the jam-releasing tool can be lowered.

[0036] like Figure 8 As shown, the pin slot 301 can be configured to meet different needs. If two consecutive pressurizations are required, a pair of normally closed points (c) and pressurization points (d) can be added between pressurization point (d) and normally open point (a). After the first pressurization is completed, the pressure is released, and the springs push the upper and lower pistons (8) to move the pin (6) from pressurization point (d) to the next normally closed point (c). The small hole on the side of the lower piston (8) closes, allowing for further pressurization.

Claims

1. A downhole flow control opening and closing sub, characterized in that: The invention comprises an upper joint (1), an outer shell (5), and a lower joint (10) extending in the axial direction; the upper joint (1) and the outer shell (5) are connected by threads; the outer shell (5) and the upper piston (3) are slidably connected; the upper piston (3) is through-connected, and has a boss extending outward on the top, which is connected to the rigid spring (4) and extends into the interior of the lower piston (8); the rigid spring (4) is placed in the upper cavity (2) formed by the upper joint (1), the upper piston (3), and the outer shell (5); the rigid spring (4) is sleeved on the outside of the upper piston (3), and the upper side of the rigid spring (4) is in contact with the upper piston (3). The lower side contacts the outer shell (5); the top of the lower piston (8) has a boss extending outward, which is connected to the weak spring (9); the lower piston (8) is placed in the lower joint (10) and is slidably connected to the lower joint (10); the lower joint (10) is connected to the outer shell (5) through a thread, and a weak spring (9) is placed inside; the weak spring (9) is placed in the lower cavity (7) formed by the outer shell (5), the lower joint (10), and the lower piston (8); the weak spring (9) is sleeved on the outer surface of the lower piston (8), the upper side of the weak spring (9) contacts the lower piston (8), and the lower side contacts the lower joint (10).

2. A downhole flow control opening and closing sub as claimed in claim 1, characterized in that: The interior of the upper piston (3) is through-hole, with an outward protruding boss on the top, a related pin slide groove (301) in the middle, and a soluble bottom (12) fixed at the bottom to seal the internal channel of the upper piston (3). A flow hole (302) is opened on the side of the bottom of the upper piston (3); the material used for the soluble bottom (12) is a light and high-strength soluble alloy material.

3. A downhole flow control opening and closing sub as claimed in claim 1, characterized in that: A pin hole (501) is provided in the middle of the outer shell (5).

4. A downhole flow control opening and closing sub as claimed in claim 2 or 3, characterized in that: The pin (6) passes through the pin hole (501) in the middle of the outer shell, moves in a fixed direction in the pin slide groove (301), and the pin (6) stops at a special point; the points include a normally open point (a), a throttling dead point (b), a normally closed point (c), and a pressurizing point (d), and different numbers of throttling dead points (b) and normally closed points (c) can be configured according to actual working requirements.

5. A downhole flow control opening and closing sub as claimed in claim 1, characterized in that The top of the lower piston (8) is provided with an outwardly extending boss, and the bottom is penetrated by a stepped hole; a soluble ring (11) is fixed to the last small hole of the stepped hole to reduce the diameter of the lower piston (8); the material used for the soluble ring (11) is a light and high-strength soluble alloy material.

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