A downhole controllable one-way valve and control method

Abstract

The present invention provides a downhole controllable one-way valve and a control method, including a connecting joint and a lower joint, wherein the lower end of the connecting joint is connected to the lower joint, and a track tube and a valve disc seat are sequentially sleeved in the connecting joint and the lower joint; the inner cavity of the connecting joint and the track tube is sequentially sleeved with a control cylinder, a reversing ring, a reversing pin, a limit ring and a spring from top to bottom; and a valve disc is provided on the valve disc seat. The present invention realizes the free switching between the plugging state and the pumping construction state in the oil pipe by ground ball throwing and pressure holding. In the pumping construction state, the valve disc is hidden between the control cylinder and the connecting joint, ensuring that the valve disc will not be eroded and damaged, and effectively extending its service life.

Description

Technical Field

[0001] The invention relates to a downhole controllable one-way valve and a control method thereof, which are used for plugging inside an oil pipe after construction such as fracturing or drilling, and belong to the technical field of oil and gas field reservoir transformation. Background Art

[0002] In the field of downhole tool technology for oil and gas field development, flap check valves are usually used as a measure to seal the inside of the oil pipe after fracturing or drilling, so as to achieve the function of adjusting the pipe string and preventing blowout in the oil pipe under pressure after construction. This flap check valve does not have a reverse circulation function, so it cannot be used under conditions that require reverse circulation. At the same time, the core of the sealing mechanism for sealing inside the oil pipe is the valve disc. During sand fracturing, the sand-carrying fluid directly contacts the valve disc, which can easily cause erosion and damage to the valve disc, and then the sealing function inside the oil pipe fails, causing well control risks. Summary of the invention

[0003] In order to overcome the problem that during the existing sand fracturing, the sand-carrying fluid directly contacts the valve disc, which easily causes erosion and damage of the valve disc, and then the sealing function in the oil pipe fails, causing well control risks, the present invention provides a downhole controllable one-way valve and a control method. During the fracturing process, the valve disc of the present invention can be hidden in the shell, ensuring a long service life of the one-way valve, and the switching of the sealing and opening states can be achieved by throwing a ball on the ground to hold the pressure, thereby realizing the reverse circulation function.

[0004] The technical solution adopted by the present invention is:

[0005] A downhole controllable one-way valve comprises a connecting joint and a lower joint, wherein the lower end of the connecting joint is connected to the lower joint, and a track tube and a valve disc seat are sequentially sleeved in the connecting joint and the lower joint; a control cylinder, a reversing ring, a reversing pin, a limit ring and a spring are sequentially sleeved in the inner cavity of the connecting joint and the track tube from top to bottom; and a valve disc is provided on the valve disc seat.

[0006] The connecting joint is sealed and fixedly connected to the lower joint. Steps are arranged in the connecting joint and the lower joint. The track tube and the valve disc seat are axially fixed under the limit of the connecting joint and the lower joint steps.

[0007] The control cylinder and the limit ring are threadedly fixedly connected, the reversing ring is axially fixed under the step limit of the control cylinder and the limit ring, one end of the reversing nail is embedded in the circular through hole of the reversing ring, and the other end is embedded in the track groove of the track tube.

[0008] The valve disc is fixed in the valve disc seat by a pin shaft, and the valve disc can realize circumferential rotation along the pin shaft. An opening is provided on one side of the valve disc seat. The valve disc is hidden in the opening of the valve disc seat when in an open state, and does not affect the inner diameter of the valve disc seat.

[0009] A sealing member is arranged on the end surface of the track tube in contact with the valve disc, and a sealing ring is arranged between the lower end of the track tube and the connecting joint.

[0010] A torsion spring is also arranged between the track tube, the valve disc and the valve disc seat. The torsion spring works on the pin shaft. One end of the spring arm is fixed in the circular hole on the end face of the track tube, and the other end of the spring arm contacts the lower end face of the valve disc.

[0011] The free position angle of the torsion spring arm is less than or equal to 90°.

[0012] The side wall of the track tube is provided with a track groove, and the reversing pin is slidably matched with the track groove.

[0013] The outer cylindrical surface at the lower end of the control cylinder is clearance-matched with the inner cylindrical surface at the lower end of the track tube and the inner cylindrical surface of the lower joint.

[0014] A method for controlling a downhole controllable one-way valve, the specific steps are:

[0015] When pumping or backwashing the well, the outer wall of the lower end of the control cylinder in the one-way valve contacts the inner wall of the lower joint, the spring is in a compressed state, the reversing pin is in the short groove position of the track pipe, and the valve disc is recovered between the outer wall of the lower end of the control cylinder and the inner wall of the connecting joint. At this time, the one-way valve ensures a sufficient internal diameter, and the valve disc never contacts the pumped sand-carrying liquid, ensuring that the valve disc is not damaged by erosion;

[0016] When it is necessary to adjust the drilling tool or prevent blowout in the tubing under pressure, the ball in the tubing is located on the upper inclined surface of the control cylinder. Under the action of the hydraulic pressure, the spring is further compressed, and the control cylinder drives the reversing ring and the reversing pin to move downward. The reversing pin slides on the track tube to switch the short slot to the long slot. At this time, the pump is stopped to release the pressure. Under the action of the spring elastic force, the reversing pin can slide in the long slot, and the control cylinder moves up to the upper end of the valve disc seat. The valve disc pops out and contacts the lower end surface of the track tube and the seal under the action of the torsion spring. Under the action of the pressure at the lower end of the one-way valve, an axial seal is formed to block the pressure in the lower end tubing. At this time, the ball still stays at the upper end of the one-way valve control cylinder;

[0017] After the drill bit is adjusted to the specified position under pressure, the pressure in the oil pipe increases, which can make the control cylinder move downward, compress the spring, switch the reversing pin to the short groove position of the track tube, and retract the valve disc between the outer wall of the lower end of the control cylinder and the inner wall of the connecting joint. At this time, the one-way valve switches to the pumping or backwashing well construction state.

[0018] The beneficial effects of the present invention are:

[0019] The present invention realizes free switching between the plugging state and the pumping construction state in the oil pipe by throwing a ball on the ground to hold the pressure. In the pumping construction state, the valve disc is hidden between the control tube and the connecting joint to ensure that the valve disc will not be eroded and damaged, effectively extending its service life. The plugging and opening states can be switched by throwing a ball on the ground to hold the pressure, realizing the reverse circulation function.

[0020] The following is a further description with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of the structure of a downhole controllable one-way valve.

[0022] In the figure, the reference numerals are: 1, connecting joint; 2, control cylinder; 3, reversing ring; 4, reversing pin; 5, limit ring; 6, track tube; 7, spring; 8, sealing; 9, torsion spring; 10, valve disc; 11, valve disc seat; 12, lower joint. DETAILED DESCRIPTION

[0023] Embodiment 1:

[0024] In order to overcome the problem that the sand-carrying fluid directly contacts the valve disc during the existing sand fracturing, which easily causes the valve disc to be eroded and damaged, and then the plugging function in the oil pipe fails, causing the well control risk, the present invention provides a method as follows Figure 1 The present invention shows a downhole controllable one-way valve and control method. The present invention realizes free switching between the plugging state and the pumping construction state in the oil pipe by ground ball throwing and holding pressure. In the pumping construction state, the valve disc is hidden between the control cylinder and the connecting joint to ensure that the valve disc will not be eroded and damaged, effectively extending its service life. The plugging and opening states can be switched by ground ball throwing and holding pressure, realizing the reverse circulation function.

[0025] A downhole controllable one-way valve comprises a connecting joint 1 and a lower joint 12, wherein the lower end of the connecting joint 1 is connected to the lower joint 12, and a track tube 6 and a valve disc seat 11 are sequentially sleeved in the connecting joint 1 and the lower joint 12; a control cylinder 2, a reversing ring 3, a reversing pin 4, a limit ring 5 and a spring 7 are sequentially sleeved in the inner cavity of the connecting joint 1 and the track tube 6 from top to bottom; a valve disc 10 is provided on the valve disc seat 11.

[0026] The present invention realizes free switching between the plugging state and the pumping construction state in the oil pipe by throwing a ball on the ground to hold the pressure. In the pumping construction state, the valve flap 10 is hidden between the control cylinder 2 and the connecting joint 1, ensuring that the valve flap 10 will not be eroded and damaged, effectively extending its service life. The plugging and opening states can be switched by throwing a ball on the ground to hold the pressure, realizing the reverse circulation function.

[0027] Embodiment 2:

[0028] Based on Example 1, in this embodiment, the connecting joint 1 is sealed and fixedly connected to the lower joint 12, and steps are provided in the connecting joint 1 and the lower joint 12. The track tube 6 and the valve disc seat 11 are axially fixed under the step limit of the connecting joint 1 and the lower joint 12.

[0029] The control cylinder 2 and the limit ring 5 are threadedly fixedly connected, and the reversing ring 3 is axially fixed under the step limit of the control cylinder 2 and the limit ring 5. One end of the reversing pin 4 is embedded in the circular through hole of the reversing ring 3, and the other end is embedded in the track groove of the track tube 6.

[0030] Furthermore, the inner cavities of the connecting joint 1 and the track tube 6 are sequentially sleeved with a control cylinder 2, a reversing ring 3, a reversing pin 4, a limiting ring 5, and a spring 7 from top to bottom. The control cylinder 2 and the limiting ring 5 are threadedly fixedly connected. The reversing ring 3 is axially fixed under the step limit of the control cylinder 2 and the limiting ring 5, but can rotate circumferentially. One end of the reversing pin 4 is embedded in the circular through hole of the reversing ring 3, and the other end is embedded in the track groove of the track tube 6.

[0031] The valve flap 10 is fixed in the valve flap seat 11 by a pin shaft. The valve flap 10 can realize circumferential rotation along the pin shaft. An opening is provided on one side of the valve flap seat 11. The valve flap 10 is hidden in the opening of the valve flap seat 11 when in an open state.

[0032] Furthermore, the valve flap 10 is fixed in the valve flap seat 11 by a pin shaft, and the valve flap 10 can realize circumferential rotation along the pin shaft. An opening is provided on one side of the valve flap seat 11. The valve flap 10 is hidden in the opening of the valve flap seat 11 when in the open state, and does not affect the inner diameter of the valve flap seat.

[0033] A sealing member 8 is provided on the end surface of the track tube 6 that contacts the valve flap 10 , and a sealing ring is provided between the lower end of the track tube 6 and the connecting joint 1 .

[0034] Furthermore, a seal 8 is provided on the end face where the track tube 6 contacts the valve flap 10, and a sealing ring is provided between the lower end of the track tube 6 and the connecting joint 1. When the valve flap and the seal 8 are in contact, the valve flap 10 and the track tube 6 can form an end face seal with the help of hydraulic pressure, thereby achieving pressure sealing of the oil pipe.

[0035] A torsion spring 9 is also provided between the track tube 6 , the valve disc 10 and the valve disc seat 11 . The torsion spring 9 works on the pin shaft. One end of the spring arm is fixed in the circular hole on the end face of the track tube 6 , and the other end of the spring arm contacts the lower end face of the valve disc 10 .

[0036] Furthermore, a torsion spring 9 is provided between the track tube 6, the valve disc 10 and the valve disc seat 11. The torsion spring 9 works on the pin shaft. One end of the spring arm is fixed in the circular hole on the end face of the track tube 6, and the other end of the spring arm contacts the lower end face of the valve disc 10. In the natural state, under the action of the torsion force of the torsion spring 9, the track tube 6 and the valve disc 10 are fitted together.

[0037] The free position angle of the torsion spring 9 arm is less than or equal to 90°.

[0038] Furthermore, the free position angle of the torsion spring 9 arm is less than or equal to 90°. When the angle is greater than 90°, the track tube 6 and the valve flap 10 cannot form contact due to insufficient spring torque.

[0039] The side wall of the track tube 6 is provided with a track groove, and the reversing pin 4 is slidably matched with the track groove.

[0040] Furthermore, a track groove is formed on the side wall of the track tube 6 , and the reversing pin 4 is slidably matched with the track groove. When the control cylinder 2 moves, the displacement distance of the control cylinder 2 is limited by the track groove and the reversing pin 4 .

[0041] The outer circumferential surface of the lower end of the control tube 2 is clearance-matched with the inner circumferential surface of the lower end of the track tube 6 and the inner circumferential surface of the lower joint 12 .

[0042] Furthermore, the outer cylindrical surface at the lower end of the control cylinder 2 is clearance-matched with the inner cylindrical surface at the lower end of the track tube 6 and the inner cylindrical surface of the lower joint 12. When the control cylinder 2 moves in the lower joint, the gap between the two is small, which can play a sand prevention effect and avoid affecting the valve disc sealing.

[0043] Embodiment 3:

[0044] Based on Examples 1 and 2, a method for controlling a downhole controllable one-way valve is provided in this embodiment, and the specific steps are as follows:

[0045] When the well is being pumped or backwashed, the outer wall of the lower end of the control cylinder 2 in the one-way valve contacts the inner wall of the lower joint 12, the spring 7 is in a compressed state, the reversing pin 4 is in the short groove position of the track pipe 6, and the valve disc 10 is recovered between the outer wall of the lower end of the control cylinder 2 and the inner wall of the connecting joint 1. At this time, the one-way valve ensures a sufficient inner diameter, and the valve disc 10 never contacts the pumped sand-carrying liquid, ensuring that the valve disc 10 is not damaged by erosion;

[0046] When it is necessary to adjust the drilling tool or prevent blowout in the oil pipe under pressure, the ball in the oil pipe is located on the upper inclined surface of the control cylinder 2. Under the action of the hydraulic pressure, the spring 7 is further compressed, and the control cylinder 2 drives the reversing ring 3 and the reversing pin 4 to move downward. The reversing pin 4 slides on the track tube 6 to switch the short groove to the long groove. At this time, the pump is stopped to release pressure. Under the elastic force of the spring 7, the reversing pin 4 can slide in the long groove, and the control cylinder 2 moves up to the upper end of the valve disc seat 11. The valve disc 10 pops out and contacts the lower end surface of the track tube 6 and the sealing member 8 under the action of the torsion spring 9. Under the pressure of the lower end of the one-way valve, an axial seal is formed to block the pressure in the lower end of the oil pipe. At this time, the ball still stays at the upper end of the one-way valve control cylinder 2;

[0047] After the drilling tool is adjusted to the specified position under pressure, the pressure in the oil pipe increases, which can make the control cylinder 2 move downward, compress the spring 7, switch the reversing nail 4 to the short groove position of the track tube 6, and the valve disc 10 is recovered between the outer wall of the lower end of the control cylinder 2 and the inner wall of the connecting joint 1. At this time, the one-way valve is switched to the pumping or backwashing well construction state.

[0048] The present invention realizes free switching between the plugging state and the pumping construction state in the oil pipe by throwing a ball on the ground to hold the pressure. In the pumping construction state, the valve flap 10 is hidden between the control cylinder 2 and the connecting joint 1, ensuring that the valve flap 10 will not be eroded and damaged, effectively extending its service life. The plugging and opening states can be switched by throwing a ball on the ground to hold the pressure, realizing the reverse circulation function.

[0049] The above examples are merely illustrative of the present invention and do not constitute a limitation on the protection scope of the present invention. Any design that is the same or similar to the present invention belongs to the protection scope of the present invention. The device structures and system methods not described in detail in this embodiment are all well-known technologies and commonly used methods in the industry and will not be described one by one here.

Claims

1. A method for controlling a downhole controllable one-way valve, characterized in that: A downhole controllable one-way valve is used, the one-way valve comprising a connecting joint (1) and a lower joint (12), the lower end of the connecting joint (1) being connected to the lower joint (12), the connecting joint (1) and the lower joint (12) being sleeved with a track tube (6) and a valve disc seat (11) in sequence; the inner cavities of the connecting joint (1) and the track tube (6) are sleeved with a control cylinder (2), a reversing ring (3), a reversing pin (4), a limit ring (5) and a spring (7) in sequence from top to bottom; a valve disc (10) is provided on the valve disc seat (11); a torsion spring (9) is further provided between the track tube (6), the valve disc (10) and the valve disc seat (11), the torsion spring (9) working on a pin shaft, one end of a spring arm being fixed in a circular hole on the end face of the track tube (6), the other end of the spring arm being in contact with the lower end face of the valve disc (10), and the like. touch; the free position angle of the torsion spring (9) arm is less than or equal to 90°; the outer cylindrical surface of the lower end of the control cylinder (2) is clearance-matched with the inner cylindrical surface of the lower end of the track tube (6) and the inner cylindrical surface of the lower joint (12); the connecting joint (1) is sealed and fixedly connected to the lower joint (12), and steps are provided in the connecting joint (1) and the lower joint (12); the track tube (6) and the valve disc seat (11) are axially fixed under the step limit of the connecting joint (1) and the lower joint (12); the control cylinder (2) and the limit ring (5) are threadedly fixedly connected, and the reversing ring (3) is axially fixed under the step limit of the control cylinder (2) and the limit ring (5); one end of the reversing pin (4) is embedded in the circular through hole of the reversing ring (3), and the other end is embedded in the track groove of the track tube (6); The specific steps of the downhole controllable one-way valve control method are: When the well is being pumped or backwashed, the outer wall of the lower end of the control cylinder (2) in the one-way valve contacts the inner wall of the lower joint (12), the spring (7) is in a compressed state, the reversing pin (4) is in the short groove position of the track pipe (6), and the valve disc (10) is recovered between the outer wall of the lower end of the control cylinder (2) and the inner wall of the connecting joint (1). At this time, the one-way valve ensures a sufficient internal diameter, and the valve disc (10) never contacts the pumped sand-carrying fluid, ensuring that the valve disc (10) is not damaged by erosion. When it is necessary to adjust the drilling tool or prevent blowout in the oil pipe under pressure, the ball is dropped into the oil pipe and is located on the upper inclined surface of the control cylinder (2). Under the action of the hydraulic pressure, the spring (7) is further compressed, and the control cylinder (2) drives the reversing ring (3) and the reversing pin (4) to move downward. The reversing pin (4) slides on the track pipe (6) to switch the short groove to the long groove. At this time, the pump is stopped to release the pressure. Under the elastic force of the spring (7), the reversing pin (4) can slide in the long groove. The control cylinder (2) moves upward to the upper end of the valve disc seat (11). The valve disc (10) pops out under the action of the torsion spring (9) and contacts the sealing member (8) on the lower end surface of the track pipe (6). Under the action of the pressure at the lower end of the one-way valve, an axial seal is formed to block the pressure in the oil pipe at the lower end. At this time, the ball still stays at the upper end of the one-way valve control cylinder (2); After the drilling tool is adjusted to the specified position under pressure, the pressure in the oil pipe increases, which can make the control cylinder (2) move downward, compress the spring (7), switch the reversing pin (4) to the short groove position of the track tube (6), and retract the valve disc (10) between the outer wall of the lower end of the control cylinder (2) and the inner wall of the connecting joint (1). At this time, the one-way valve is switched to the pumping or backwashing well construction state.

2. A method for controlling a downhole controllable one-way valve according to claim 1, characterized in that: The valve flap (10) is fixed in the valve flap seat (11) via a pin shaft, and the valve flap (10) can realize circumferential rotation along the pin shaft. An opening is provided on one side of the valve flap seat (11), and the valve flap (10) is hidden in the opening of the valve flap seat (11) in the open state without affecting the inner diameter of the valve flap seat (11).

3. A method for controlling a downhole controllable one-way valve according to claim 1, characterized in that: A sealing member (8) is provided on the end surface of the track tube (6) that contacts the valve flap (10), and a sealing ring is provided between the lower end of the track tube (6) and the connecting joint (1).

4. A method for controlling a downhole controllable one-way valve according to claim 1, characterized in that: The side wall of the track tube (6) is provided with a track groove, and the reversing pin (4) is slidably engaged with the track groove.

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