A quick self-sealing device for a broken rod of a direct-drive screw pump

Abstract

This invention relates to the field of screw pump well sealing tools, and more particularly to a rapid self-sealing device for a direct-drive screw pump rod breakage. This rapid self-sealing device for a direct-drive screw pump rod breakage includes a sealing box installed at the top outlet of the bearing housing of the direct-drive screw pump wellhead. The sealing box contains a first sealing cavity and a second sealing cavity arranged sequentially from top to bottom. The first sealing cavity seals the sucker rod, and the side wall of the second sealing cavity has a ball channel containing a spring and a blowout preventer (BOP). After the sucker rod breaks off, the BOP enters the second sealing cavity and seals it. The rapid self-sealing device for a direct-drive screw pump rod breakage proposed in this invention, by providing a radial ball channel within the second sealing cavity, and housing a spring and a BOP within the ball channel, allows the spring to push the BOP to the middle of the second sealing cavity for sealing when the sucker rod breaks off, thus achieving wellhead sealing upon sucker rod breakage. By installing the device at the top of the pumping unit bearing housing, no modifications to the existing device structure are required, reducing workload.

Description

Technical Field

[0001] This invention relates to the field of screw pump well sealing tools, and in particular to a rapid self-sealing device for broken rods in a direct-drive screw pump. Background Technology

[0002] In oilfield production, screw pump wells are among the most common production equipment. During operation, a motor-driven downhole screw pump lifts oil to the surface. However, in actual operation, due to the square clamps installed above the sucker rod at the wellhead, fatigue fracture can occur under centrifugal force and radial shear force. Under downhole pressure, some well fluid will leak from the gap between the sucker rod and the wellhead. Existing technology includes a screw pump wellhead sealing device that seals the sucker rod by tightening packing, preventing downhole fluid from leaking out of the wellhead along the gaps around the sucker rod, causing waste and environmental pollution. However, during prolonged operation, friction and collisions between the sucker rod and wellhead devices such as packing, coupled with vibrations during downhole production, can transmit these vibrations to the sucker rod, causing it to break and fall into the wellhead. At this point, the inlet sealing device cannot seal the wellhead after the sucker rod breaks off, resulting in a large amount of downhole production fluid splashing out of the wellhead, causing significant production losses and environmental pollution. Therefore, in order to address the above shortcomings, a rapid self-sealing device for broken rods in direct-drive screw pumps is proposed. Summary of the Invention

[0003] (a) Technical problems to be solved To address the shortcomings of existing technologies, this invention provides a rapid self-sealing device for broken sucker rods in direct-drive screw pumps, which solves the problem that existing devices cannot seal the wellhead of the pumping unit after the sucker rod breaks off.

[0004] (II) Technical Solution To address the above problems, this invention provides a rapid self-sealing device for broken rods in a direct-drive screw pump, comprising: A sealing box is installed at the top outlet of the bearing housing at the wellhead of the pumping unit. The pumping unit rod passes through the sealing box and the bearing housing and enters the well. The bottom dimension of the sealing box matches the top outlet of the bearing housing. The top of the sealing box has a first sealing cavity and an inner second sealing cavity. The first and second sealing cavities are arranged concentrically, and the pumping unit rod passes downward through the first and second sealing cavities. A radially penetrating ball track is provided on the side wall of the sealing box corresponding to the second sealing cavity. A blowout preventer ball and a spring are provided in the ball track. The spring pushes the blowout preventer ball towards the center of the second sealing cavity. After the rod breaks, it passes through the sealing box along the first and second sealing cavities, and the blowout preventer ball falls into the second sealing cavity to seal it.

[0005] Preferably, the diameter of the blowout ball matches the inner diameter of the ball track and is larger than the diameter of the second sealing cavity.

[0006] Preferably, the first sealing cavity is provided with an O-ring packing, and the sucker rod passes through the through hole in the middle of the O-ring packing and enters the second sealing cavity downward.

[0007] Preferably, the first sealing cavity is located above the second sealing cavity, the diameter of the first sealing cavity is larger than that of the second sealing cavity, the bottom end of the first sealing cavity and the top end of the second sealing cavity form a stepped structure, and the O-ring packing is located on the stepped structure.

[0008] Preferably, the top of the first sealing cavity is provided with a sealing cap to seal the top of the sealing box.

[0009] Preferably, a plurality of fixing bolts are evenly provided at the edge of the upper surface of the sealing cap to fix the sealing cap to the top of the sealing box.

[0010] Preferably, the outermost end of the ball track is provided with a sealing bolt, which is connected to the outer wall of the sealing box by a thread.

[0011] Preferably, the sealing bolt is located outside the spring, with one end of the spring contacting the inner wall of the sealing bolt and the other end contacting the blowout preventer.

[0012] Preferably, a gland is provided below the O-ring packing, and the gland clamps the O-ring packing with the bottom end of the sealing cap.

[0013] (III) Beneficial Effects The present invention provides a rapid self-sealing device for a direct-drive screw pump when the sucker rod breaks off. This device features a radial ball channel within a second sealing cavity, containing a spring and a blowout preventer (BOP). The spring, under its own elasticity, pushes the BOP into the second sealing cavity. When the sucker rod breaks off, the spring pushes the BOP to the center of the second sealing cavity, sealing it and preventing well fluid from spraying out, thus achieving wellhead sealing upon sucker rod breakage. Furthermore, by directly installing the device on top of the pumping unit's bearing housing, no structural modifications to the existing pumping unit are required, reducing the labor intensity and workload for operators. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the structure of the quick self-sealing device for broken rods in a direct-drive screw pump according to the present invention.

[0015] The components are: 1. Sealing box; 2. First sealing cavity; 3. Second sealing cavity; 4. Ball track; 5. Blowout ball; 6. Spring; 7. O-ring packing; 8. Sealing cap; 9. Fixing bolt; 10. Sealing bolt; 11. Gland. Detailed Implementation

[0016] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0017] In the description of this invention, it is necessary to understand that the orientation or positional relationship indicated by terms such as "upper", "lower", "inner", "outer", "top", and "bottom" are based on the orientation or positional relationship shown in the accompanying drawings. The purpose is only to facilitate the description of this invention and to simplify the description. It is not intended to indicate or imply that the component referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of this invention.

[0018] like Figure 1 As shown, this invention provides a rapid self-sealing device for broken sucker rods in a direct-drive screw pump. Specifically, it includes a sealing box 1 installed at the top outlet of the bearing housing at the wellhead of the pumping unit. The sucker rod passes through the sealing box 1 and the bearing housing before entering the well. The sealing box 1 serves as the main body of the device, primarily providing support and load-bearing capacity. Other components within the device are installed inside the sealing box 1 to form a unified whole. Normally, during pumping unit operation, the sucker rod extends into the well after passing through the bearing housing at the top outlet. After installing the sealing box 1 at the top outlet of the bearing housing, the sucker rod, during operation, first passes through the sealing box 1 and then through the bearing housing, performing periodic up-and-down reciprocating motion driven by the power source, thus driving the downhole pump to perform pumping operations.

[0019] For ease of installation, the bottom dimension of the sealing box 1 is matched with the top outlet of the bearing housing. Generally, a matching thread structure is machined into the bottom of the sealing box 1 and the top of the bearing housing. During installation, simply rotating the sealing box 1 is sufficient to install the device onto the top outlet of the bearing housing, reducing installation difficulty and workload. Alternatively, the bottom of the sealing box 1 can be machined to fit the existing top sealing box of the pumping unit, allowing it to be directly installed on top of the existing top sealing box. This enables it to work in conjunction with the top sealing box to seal the pumping unit wellhead, improving the device's operating efficiency.

[0020] In this invention, the top of the sealing box 1 is provided with a first sealing cavity 2, and the interior is provided with a second sealing cavity 3. The first sealing cavity 2 and the second sealing cavity 3 are arranged concentrically, and the sucker rod passes downward through the first sealing cavity 2 and the second sealing cavity 3. The first sealing cavity 2 and the second sealing cavity 3 are isolated from each other during operation. The first sealing cavity 2 is used to seal the sucker rod passing through the sealing box 1 to prevent downhole fluid from splashing from the wellhead and causing fluid leakage during operation. The second sealing cavity 3 mainly plays a blowout prevention role. During normal operation, the sucker rod passes normally through the second sealing cavity 3. When the sucker rod breaks off, the broken sucker rod will fall downward along the sealing box 1 into the pumping unit well under the action of gravity. At this time, the second sealing cavity 3 automatically seals, blocking the channel inside the sealing box 1. The fluid below cannot continue to flow upward through the second sealing cavity 3, thereby achieving blowout prevention sealing treatment at the pumping unit wellhead when the sucker rod breaks off, avoiding downhole fluid from splashing from the wellhead after the sucker rod breaks off, which would cause production waste and environmental pollution.

[0021] The first sealing cavity 2 is equipped with an O-ring packing 7, through which the sucker rod passes downward into the second sealing cavity 3 via a through-hole in the center of the O-ring packing 7. The O-ring packing 7 is mainly used to seal the sucker rod, preventing liquid below from flowing out of the wellhead through the gaps around the sucker rod. Typically, after the O-ring packing 7 is installed and the sucker rod passes through it, the O-ring packing 7 is axially compressed, causing it to deform inward and thus making tight contact with the sucker rod, achieving a sealing effect. Generally, the diameter of the first sealing cavity 2 is larger than that of the second sealing cavity 3, and the bottom of the first sealing cavity 2 and the top of the second sealing cavity 3 form a stepped structure, with the O-ring packing 7 located on this stepped structure.

[0022] It should be noted that a sealing cap 8 is provided at the top of the first sealing cavity 2 to seal the top of the sealing box 1. The sealing cap 8 is fixed to the top of the sealing box 1 to prevent the O-ring packing 7 from sliding out of the first sealing cavity 2 due to the friction between it and the sucker rod during operation. This avoids the device's sealing failure caused by the O-ring packing 7 sliding out of the first sealing cavity 2, and improves the stability of the device.

[0023] It should be noted that several fixing bolts 9 are evenly distributed along the edge of the upper surface of the sealing cap 8 to fix the sealing cap 8 to the top of the sealing box 1. The sealing cap 8 is connected to the sealing box 1 by the fixing bolts 9 to prevent the upward-moving O-ring packing 7 from causing the sealing cap 8 to move upward. Under normal circumstances, the bottom end of the sealing cap 8 extends downward from the top of the sealing box 1 into the first sealing cavity 2 and contacts the O-ring packing 7. When installing the sealing cap 8, the pressure of the sealing cap 8 pressing down on the O-ring packing 7 can be adjusted by adjusting the tightness of the fixing bolts 9. After long-term operation, the O-ring packing 7 will wear due to friction with the sucker rod. At this time, tightening the fixing bolts 9 will push the sealing cap 8 downward to further compress the O-ring packing 7, increasing the deformation of the O-ring packing 7 and making it fit tightly with the sucker rod again. A gland 11 is provided below the O-ring packing 7, and the gland 11 clamps the O-ring packing 7 with the bottom end of the sealing cap 8. The gland 11 and the O-ring packing 7 work together to isolate the first sealing cavity 2 and the second sealing cavity 3. During operation, the gland 11 is located on the stepped structure between the first sealing cavity 2 and the second sealing cavity 3. The gland 11 lifts the O-ring packing 7 upward, making it easier for the O-ring packing 7 to contact the bottom end of the sealing cap 8. During operation, the sealing cap 8 under the same conditions can apply greater pressure to the O-ring packing 7, thereby increasing the maximum friction level when the O-ring packing 7 can maintain its sealing ability for the sucker rod during operation and extending the service life of the device.

[0024] like Figure 1 As shown, the side wall of the sealing box 1 has a radially penetrating ball track 4 corresponding to the second sealing cavity 3. The ball track 4 contains a blowout preventer ball 5 and a spring 6. The spring 6 pushes the blowout preventer ball 5 towards the center of the second sealing cavity 3. After the sucker rod breaks, it passes through the sealing box 1 along the first sealing cavity 2 and the second sealing cavity 3, and the blowout preventer ball 5 falls into the second sealing cavity 3, sealing it. Typically, the blowout preventer ball 5 is made of a material with low hardness and good elasticity, such as rubber. During operation, the blowout preventer ball 5 is pushed towards the center of the second sealing cavity 3 by the spring 6, contacting the sucker rod. Using a low-hardness, high-elasticity material like rubber reduces wear on the sucker rod during operation, preventing the blowout preventer ball 5 from damaging the sucker rod and improving the stability of the device. After the sucker rod breaks off, the broken sucker rod falls downwards along the sealing box 1 into the pumping unit well. The liquid in the well flows upwards under the action of downhole pressure. When the blowout preventer ball 5 is pushed into the second sealing chamber 3, the blowout preventer ball flows upwards with the liquid and gets stuck in the second sealing chamber 3, sealing the second sealing chamber 3 and preventing the liquid from continuing to flow upwards. This achieves the purpose of sealing the pumping unit wellhead to prevent splashing when the sucker rod breaks off.

[0025] The diameter of the blowout preventer ball 5 matches the inner diameter of the ball track 3 and is slightly larger than the inner diameter of the second sealing cavity 3. After the blowout preventer ball 5 falls into the second sealing cavity 3, because its diameter is larger than the inner diameter of the second sealing cavity 3, it will not move upwards when pushed by the liquid below, but will instead seal the second sealing cavity 3, thus achieving the anti-splash operation. A sealing bolt 10 is provided at the outermost end of the ball track 4, and the sealing bolt 10 is threadedly connected to the outer wall of the sealing box 1. The sealing bolt 10 is located outside the spring 6, with one end of the spring 6 contacting the inner wall of the sealing bolt 10 and the other end contacting the blowout preventer ball 5. After one end of the spring 6 abuts against the inner wall of the sealing bolt 10, it uses its own elasticity to push the blowout preventer ball 5 into the second sealing cavity 3. During operation, adjusting the connection depth of the sealing bolt 10 within the ball track 4 can change the compression of the spring 6, thereby changing the elastic force of the spring 6. In actual operation, the connection depth of the sealing bolt 10 within the ball track 4 is adjusted according to the working requirements to adjust the elastic force of the spring 6 to match the working requirements.

[0026] The rapid self-sealing device for broken sucker rods in a direct-drive screw pump provided by this invention can automatically seal the wellhead of the screw pump to prevent downhole fluid splashing when the sucker rod breaks off. The specific working process of this device is as follows: Step 1: After assembling the device according to its structure, install it at the top outlet of the inlet bearing housing of the oil pumping unit.

[0027] Step 2: Lower the sucker rod from top to bottom through the first and second sealing chambers of the sealing housing, then through the bearing housing into the pumping unit well, and start the pumping unit. At this time, the sucker rod moves up and down periodically under the drive of the pumping unit, driving the downhole pump to draw oil from the well. The O-ring packing deforms towards the sucker rod under the pressure of the gland and the sealing cap, contacting the sucker rod and sealing the gaps around the sucker rod to prevent downhole fluid from flowing out from the gaps around the sucker rod.

[0028] Step 3: When the sucker rod breaks off, the spring activates to seal the wellhead of the pumping unit via the blowout preventer (BOP), thus preventing blowout. During this process, after the sucker rod breaks off, it falls downwards into the pumping unit well. The downhole fluid flows upwards, and the spring, under its own elastic force, pushes the BOP into the second sealing chamber. The upward flow of the downhole fluid further pushes the BOP upwards. Because the diameter of the BOP is larger than the second sealing chamber, the BOP does not move upwards with the fluid but instead seals the second sealing chamber, preventing the fluid from continuing to flow upwards, thereby achieving blowout prevention at the wellhead.

[0029] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention 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 or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A rapid self-sealing device for broken rods in a direct-drive screw pump, characterized in that, include: A sealing box (1) is installed at the top outlet of the bearing housing at the wellhead of the direct-drive screw pump. The sucker rod passes through the sealing box (1) and the bearing housing and is lowered into the well. The bottom dimension of the sealing box (1) matches the top outlet of the bearing housing. The sealing box (1) has a first sealing cavity (2) and a second sealing cavity (3) arranged from top to bottom. The first sealing cavity (2) and the second sealing cavity (3) are arranged concentrically. The sucker rod passes downward through the first sealing cavity (2) and the second sealing cavity (3). The first sealing cavity (1) controls the sucker rod. After the sucker rod breaks off, the second sealing cavity (3) seals the sealing box (1); the side wall of the sealing box (1) is provided with a radially penetrating ball track (4) corresponding to the second sealing cavity (3). The ball track (4) is provided with a blowout preventer ball (5) and a spring (6). The spring (6) pushes the blowout preventer ball (5) towards the center of the second sealing cavity (3). After the sucker rod breaks off, it passes through the sealing box (1) along the first sealing cavity (2) and the second sealing cavity (3). The blowout preventer ball (5) falls into the second sealing cavity (3) and seals the second sealing cavity (3).

2. The rapid self-sealing device for broken rods in a direct-drive screw pump according to claim 1, characterized in that, The diameter of the blowout ball (5) matches the inner diameter of the ball track (4) and is larger than the diameter of the second sealing cavity (3).

3. The rapid self-sealing device for broken rods of a direct-drive screw pump according to claim 1, characterized in that, The first sealing cavity (2) is provided with an O-ring packing (7), and the sucker rod passes through the through hole in the middle of the O-ring packing (7) and enters the second sealing cavity (3) downward.

4. The rapid self-sealing device for broken rods of a direct-drive screw pump according to claim 3, characterized in that, The first sealing cavity (2) is located above the second sealing cavity (3). The diameter of the first sealing cavity (2) is larger than that of the second sealing cavity (3). The bottom end of the first sealing cavity (2) and the top end of the second sealing cavity (3) form a stepped structure. The O-type packing (7) is located on the stepped structure.

5. The rapid self-sealing device for broken rods of a direct-drive screw pump according to claim 4, characterized in that, The top of the first sealing cavity (2) is provided with a sealing cap (8) to seal the top of the sealing box (1).

6. The rapid self-sealing device for broken rods of a direct-drive screw pump according to claim 5, characterized in that, Several fixing bolts (9) are evenly arranged at the edge of the upper surface of the sealing cap (8) to fix the sealing cap (8) to the top of the sealing box (1).

7. The rapid self-sealing device for broken rods of a direct-drive screw pump according to claim 1, characterized in that, The outermost end of the ball track (4) is provided with a sealing bolt (10), which is connected to the outer wall of the sealing box (1) by a thread.

8. The rapid self-sealing device for broken rods of a direct-drive screw pump according to claim 7, characterized in that, The sealing bolt (10) is located outside the spring (6), with one end of the spring (6) in contact with the inner wall of the sealing bolt (10) and the other end in contact with the blowout ball (5).

9. The rapid self-sealing device for broken rods of a direct-drive screw pump according to claim 6, characterized in that, Below the O-type packing (7) is a gland (11), which clamps the O-type packing (7) with the bottom end of the sealing cap (8).

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