Negative pressure drainage device

Abstract

The utility model relates to the technical field of oil well liquid drainage, in particular to a negative pressure liquid drainage device. Comprising an upper connector, a sealing conical surface is formed in the upper connector, the lower end of the upper connector is fixedly and hermetically connected with an outer cylinder, the lower end of the outer cylinder is fixedly and hermetically connected with a lower connector, a piston blind plate is arranged in the lower connector, connected with the lower connector through a shear pin and in sealed contact with the upper connector, and a screen pipe is fixedly and hermetically connected in the lower end of the piston blind plate. The lower end of the screen pipe extends to the position below the lower connector and is blocked. The screen pipe and the piston blind plate are automatically released through fracture of the shear pin, external power or manual intervention is not needed, instant communication of a shaft and an oil pipe column is achieved, and the liquid drainage starting time is remarkably shortened.

Description

Technical Field

[0001] This utility model relates to the field of oil well drainage technology, specifically to a negative pressure drainage device. Background Technology

[0002] During oilfield operations, some wells experience fluid accumulation, which prevents further operations from proceeding. Therefore, the accumulated fluid in the wellbore needs to be drained. In conventional operations, water pumps are used to drain the fluid from the wellbore, but this device uses a liquid lifting method.

[0003] Current technology for draining water from inside a well requires lowering a water pump into the well to pump out the liquid. This operation is time-consuming and poses certain safety hazards. Utility Model Content

[0004] The main objective of this invention is to provide a negative pressure drainage device that enables water extraction during oil well operations. This device achieves drainage using a purely mechanical structure, significantly reducing the workload of personnel, saving considerable time, and minimizing the risks associated with on-site operations compared to previous methods.

[0005] To achieve the above objectives, the technical solution provided by this utility model is as follows:

[0006] The negative pressure drainage device includes an upper connector with a sealing cone surface inside. An outer cylinder is fixedly and sealed to the lower end of the upper connector, and a lower connector is fixedly and sealed to the lower end of the outer cylinder. A piston blind plate is installed inside the lower connector and is connected to the lower connector by a shear pin. The piston blind plate is in sealing contact with the upper connector. A screen tube is fixedly and sealed to the lower end of the piston blind plate, and the lower end of the screen tube extends to the lower connector and is sealed.

[0007] Specifically, a sealing ring is provided between the upper connector and the outer cylinder, a sealing ring is provided between the lower connector and the outer cylinder, and a sealing ring is provided between the piston blind plate and the lower connector.

[0008] Specifically, a gap is provided between the inner wall of the lower connector and the outer wall of the screen tube.

[0009] Specifically, a plug is fixed at the lower end of the screen tube, and the plug is threadedly connected to the lower end of the screen tube.

[0010] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0011] 1. The screen pipe and piston blind plate are automatically released by the breakage of the shear pin, without the need for external power or manual intervention, realizing instantaneous connection between the wellbore and the tubing string, and significantly shortening the fluid discharge start-up time.

[0012] 2. Sealing rings are installed between the upper connector, outer cylinder, lower connector and piston blind plate to ensure that the device is leak-free under high pressure environment and reduce well control risks caused by liquid leakage.

[0013] 3. The hard seal between the steel ball and the sealing cone surface can completely seal the tubing during the lifting process, preventing liquid backflow or pressure imbalance and ensuring stable and controllable operation.

[0014] 4. The gap between the lower connector and the screen tube promotes uniform liquid flow and avoids local blockage. At the same time, the liquid passage holes on the surface of the screen tube can filter impurities and reduce the risk of device jamming.

[0015] 5. The threaded plugs not only protect the lower end of the screen pipe from deformation when it hits the bottom of the well, but also facilitate disassembly during surface drainage, thus extending the service life of the device.

[0016] 6. Fluid drainage can be completed simply by dropping a steel ball and lifting the tubing string, eliminating the need for frequent personnel downhole operations and reducing exposure time under high pressure. Its functionality relies entirely on mechanical structures, avoiding the risks associated with electrical or hydraulic system failures, making it particularly suitable for oil wells in remote or complex conditions. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the device.

[0018] The parts in the attached diagram are named as follows: 1. Upper connector, 2. Steel ball, 3. Outer cylinder, 4. Piston blind plate, 5. Shear pin, 6. Lower connector, 7. Screen tube, 8. Plug. Detailed Implementation

[0019] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present utility model. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments.

[0020] Example 1: Refer to Figure 1 As shown, the negative pressure drainage device includes an upper connector 1, which has a sealing cone surface. After the steel ball 2 enters the upper connector 1, it contacts the sealing cone surface. The cooperation between the steel ball 2 and the sealing cone surface can seal the upper connector 1.

[0021] The lower end of the upper connector 1 is fixedly and sealed to the outer cylinder 3. A sealing ring is provided between the upper connector 1 and the outer cylinder 3. The lower end of the outer cylinder 3 is fixedly and sealed to the lower connector 6. A sealing ring is provided between the lower connector 6 and the outer cylinder 3. A piston blind plate 4 is provided inside the lower connector 6. The piston blind plate 4 is connected to the lower connector 6 through a shear pin 5. The piston blind plate 4 is in sealing contact with the upper connector 1. A sealing ring is provided between the piston blind plate 4 and the lower connector 6. A screen tube 7 is fixedly and sealed to the lower end of the piston blind plate 4. The lower end of the screen tube 7 extends to the lower connector 6. A gap is provided between the inner wall of the lower connector 6 and the outer wall of the screen tube 7. The lower end of the screen tube 7 is sealed.

[0022] In use, first connect this device to the tubing string, then run it down the well. During the running-down process, the pressure inside the wellbore increases. The tubing string causes the lower end of the screen pipe 7 to impact the bottom of the well and cut the shear pin 5. After the shear pin 5 breaks, the screen pipe 7 and the piston blind plate 4 will move upward under the impact. When the piston blind plate 4 separates from the lower connector 6, the fluid inlet at the upper part of the screen pipe 7 is located inside the outer cylinder 3, and the inside of the tubing string is connected to the wellbore. The fluid inside the wellbore will enter the tubing string through the fluid passage on the screen pipe 7 and the gap between the lower connector 6 and the screen pipe 7.

[0023] Once the pressure inside the wellbore and the tubing string is equal, steel ball 2 is inserted into the tubing string. After steel ball 2 makes sealing contact with the sealing cone surface of the upper connector 1, the tubing string is lifted up. The liquid inside the tubing string cannot be discharged and is lifted to the ground along with the tubing string.

[0024] Example 2: Based on Example 1, referring to... Figure 1 As shown, a plug 8 is fixed at the lower end of the screen tube 7, and the plug 8 is threadedly connected to the lower end of the screen tube 7.

[0025] By installing the plug 8, deformation of the lower end of the screen pipe 7 can be prevented when impacting the bottom of the well. At the same time, after the device is brought to the surface with the tubing string, the plug 8 can be removed to facilitate the drainage of liquid inside the screen pipe 7.

[0026] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A negative pressure drainage device comprising an upper connector (1), a sealing cone is arranged in the upper connector (1), characterized in that, The lower end of the upper connector (1) is fixedly and sealed to the outer cylinder (3), and the lower end of the outer cylinder (3) is fixedly and sealed to the lower connector (6). A piston blind plate (4) is provided inside the lower connector (6). The piston blind plate (4) is connected to the lower connector (6) through a shear pin (5). The piston blind plate (4) is in sealed contact with the upper connector (1). A screen tube (7) is fixedly and sealed to the lower end of the piston blind plate (4). The lower end of the screen tube (7) extends to the lower connector (6) and the lower end of the screen tube (7) is sealed.

2. The negative pressure drainage device according to claim 1, wherein A sealing ring is provided between the upper connector (1) and the outer cylinder (3), a sealing ring is provided between the lower connector (6) and the outer cylinder (3), and a sealing ring is provided between the piston blind plate (4) and the lower connector (6).

3. The negative pressure drainage device according to claim 1, wherein A gap is provided between the inner wall of the lower connector (6) and the outer wall of the screen tube (7).

4. The negative pressure drainage device according to claim 1, wherein A plug (8) is fixed at the lower end of the screen tube (7), and the plug (8) is threadedly connected to the lower end of the screen tube (7).

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