A packer for establishing a zero pressure zone at the wellhead of an injection well

Abstract

The application discloses a packer for establishing a zero-pressure area at a water injection well head, and belongs to the technical field of packers. The technical scheme comprises a movable outer cylinder which is sleeved on a cylinder body, an outer sealing unit is arranged between the outer cylinder and the cylinder body, an inner sealing unit in the form of screwing is arranged in the outer cylinder and the cylinder body, and a closing unit is arranged at the top of the outer cylinder. The packer has the beneficial effects that the inner pressure of the tubing string at the water injection well head and the pressure in the oil-casing annular space can be effectively controlled, and the occurrence of problems such as safety risks in the process of replacing a fault valve can be prevented.

Description

Technical Field

[0001] This invention relates to a packer for establishing a zero-pressure zone at the wellhead of a water injection well, belonging to the field of packer technology. Background Technology

[0002] Water injection is a common method for stabilizing and increasing oil production during oilfield development. Injecting water into the reservoir replenishes formation energy and improves crude oil recovery. However, during water injection, wellhead valves may experience various problems, such as damage, leakage at the lead screw, and internal leakage within the valve body. This is especially true in northern winters, where the probability of valve failure is higher. These valve problems pose environmental and safety hazards that urgently need to be addressed. Furthermore, due to the structure of water injection wells, high-pressure zones are commonly present at the wellhead, making valve replacement extremely risky and potentially leading to valve body cracking, threatening environmental and personnel safety. Therefore, effectively establishing a zero-pressure zone at the wellhead of water injection wells to ensure stability and safety during the handling of faulty valves is a problem that needs to be solved by those skilled in the art.

[0003] Chinese patent application CN104314512A discloses a wellhead hanging packer. In practical use, the wellhead hanging packer is fitted onto the outside of the inner casing, and the bolts are tightened. The upper cover plate and bottom plate simultaneously compress the slips and rubber core, causing the rubber core to expand and seal the casing annulus. The slips then move downwards, their teeth embedding into the surface of the inner casing, preventing the wellhead packer from moving upwards under annular pressure. However, this technical solution only seals the casing annulus and cannot control the pressure inside the tubing string at the wellhead of water injection wells, nor can it avoid safety risks during valve replacement operations. Summary of the Invention

[0004] This invention provides a packer for establishing a zero-pressure zone at the wellhead of a water injection well. It can effectively control the pressure inside the wellhead tubing and casing, thereby establishing a zero-pressure zone at the wellhead of the water injection well and ensuring the safety and effectiveness of water injection operations.

[0005] The technical solution of the present invention is: a packer for establishing a zero-pressure zone at the wellhead of a water injection well, comprising a movable outer cylinder sleeved on a cylindrical body, an outer sealing unit provided between the outer cylinder and the cylindrical body, a screw-in inner sealing unit provided in the outer cylinder and the cylindrical body, and a sealing unit provided at the top of the outer cylinder.

[0006] The top of the cylinder extends above the enclosed unit.

[0007] The top of the cylinder is fixed to the wellhead by an oil pipe.

[0008] The bottom of the cylinder is connected to an oil pipe.

[0009] The external sealing unit includes an upper rubber sleeve and a lower rubber sleeve fitted on the cylinder body, and a spacer sleeve fitted on the cylinder body is provided between the upper rubber sleeve and the lower rubber sleeve.

[0010] The top of the upper rubber tube contacts the bottom of the outer cylinder, and the bottom of the lower rubber tube contacts the fixing ring at the bottom of the cylinder.

[0011] The inner sealing unit includes an inner plug, an inner sealing ring is fitted around the outer periphery of the inner plug, guide posts are provided on both sides of the top of the inner plug, and a guide shoe is provided on the inner wall of the cylinder to guide the movement of the guide post. A positive rotation groove is opened on the cylinder at the bottom of the guide shoe, and a positioning guide post is provided at the bottom of the positive rotation groove.

[0012] There are three inner sealing rings, which are distributed in parallel at equal intervals.

[0013] The inner plug is removably threaded at the bottom of the swivel.

[0014] The sealing unit is a pressure cap.

[0015] The beneficial effects of this invention are as follows:

[0016] (1) Effectively control the pressure inside the tubing string at the wellhead of the water injection well and the pressure inside the annular space of the casing to prevent safety risks and other problems during the replacement of faulty valves.

[0017] (2) By establishing a zero-pressure zone, the risk of construction is reduced and the environment is protected.

[0018] (3) It improves the safety of water injection operations and reduces potential threats to personnel.

[0019] (4) Simplify the packer structure, facilitate operation, and reduce maintenance costs. Attached Figure Description

[0020] Figure 1 This is an external view of the present invention;

[0021] Figure 2 This is a cross-sectional view of the present invention;

[0022] Figure 3 This is an exploded view of the present invention;

[0023] Figure 4 This is an external view of the cylinder.

[0024] Figure 5 This is a sectional view of the cylinder;

[0025] Figure 6 This is a cross-sectional view of the internal plug.

[0026] The following labels are used in the attached diagram: 1. Cylinder body, 1.1. Fixed retaining ring, 1.2. Positive rotation groove, 2. Inner sealing ring, 3. Inner plug, 3.1. Guide post, 4.1. Upper rubber sleeve, 4.2. Lower rubber sleeve, 5. Spacer, 6. Outer cylinder body, 7. Pressure cap, 8. Rotary rod. Detailed Implementation

[0027] To more clearly illustrate the technical solutions of the embodiments of the present invention, the present invention will be described in detail below with reference to the accompanying drawings and detailed embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0029] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0030] Secondly, the present invention is described in detail with reference to the schematic diagrams. When detailing the embodiments of the present invention, for ease of explanation, the cross-sectional views illustrating the device structure may be partially enlarged, not according to the usual scale. Furthermore, the schematic diagrams are merely examples and should not limit the scope of protection of the present invention. In addition, actual fabrication should include three-dimensional spatial dimensions of length, width, and depth.

[0031] The following is in conjunction with the appendix Figure 1-6 The present invention will be described in further detail as follows:

[0032] Example 1

[0033] A packer for establishing a zero-pressure zone at the wellhead of a water injection well includes a movable outer cylinder 6 fitted onto a cylindrical body 1. An external sealing unit is provided between the outer cylinder 6 and the cylindrical body 1. Screw-in internal sealing units are provided in both the outer cylinder 6 and the cylindrical body 1. A pressure cap 7 is provided at the top of the outer cylinder 6. The top of the cylindrical body 1 extends through and above the pressure cap 7. The top of the cylindrical body 1 is fixed to the wellhead via tubing. Tubing is connected to the bottom of the cylindrical body 1.

[0034] The external sealing unit includes an upper rubber sleeve 4.1 and a lower rubber sleeve 4.2 fitted onto the cylinder body 1, with a spacer 5 fitted onto the cylinder body 1 between the upper rubber sleeve 4.1 and the lower rubber sleeve 4.2. The top end of the upper rubber sleeve 4.1 contacts the bottom end of the outer cylinder body 6, and the bottom end of the lower rubber sleeve 4.2 contacts the bottom retaining ring 1.1 of the cylinder body 1.

[0035] The inner sealing unit includes an inner plug 3, with three inner sealing rings 2 sleeved around the outer periphery of the inner plug 3. The three inner sealing rings 2 are evenly spaced and parallel. Guide posts 3.1 are provided on both sides of the top of the inner plug 3. The inner wall of the cylinder 1 is provided with guide shoes to guide the movement of the guide posts 3.1. A positive rotation groove 1.2 is opened on the bottom end of the cylinder 1 of the guide shoes. The bottom of the positive rotation groove 1.2 is provided with a slot for positioning the guide post 3.1.

[0036] Example 2

[0037] When it is necessary to remove the inner plug 3, the bottom of the rotating rod 8 is connected to the inner plug 3 by means of a threaded connection. By rotating the rotating rod 8, the inner plug 3 can be removed, and the normal flow in the oil pipe can be restored.

[0038] Example 3

[0039] The primary function of this packer is to simultaneously seal the well fluid within the annular space of the tubing and casing. Its operation involves using pump pressure to insert the inner plug 3 into the casing 1. The guide post 3.1 on the inner plug 3 rotates and moves downwards through the guide shoe inside the casing 1 into the positive spiral groove 1.2 at the bottom of the casing 1. The inner plug 3 continues downwards, eventually stopping at the latch at the bottom of the positive spiral groove 1.2, thereby pushing the outer rubber sleeve of the packer to expand and seal, thus sealing the annular space of the wellhead casing. The three inner sealing rings 2 seal against the inner wall of the casing 1, sealing the wellhead tubing and establishing a complete zero-pressure zone at the wellhead. Repair and replacement of the inner and outer valves can then be performed.

[0040] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A packer for establishing a zero-pressure zone at the wellhead of a water injection well, characterized in that, It includes a movable outer cylinder (6) sleeved on the cylinder (1), an outer sealing unit is provided between the outer cylinder (6) and the cylinder (1), a screw-in inner sealing unit is provided in the outer cylinder (6) and the cylinder (1), and a sealing unit is provided at the top of the outer cylinder (6).

2. The packer for establishing a zero-pressure zone at the wellhead of a water injection well according to claim 1, characterized in that, The top of the cylinder (1) extends above the enclosed unit.

3. The packer for establishing a zero-pressure zone at the wellhead of a water injection well according to claim 2, characterized in that, The top of the cylinder (1) is fixed to the wellhead by an oil pipe.

4. The packer for establishing a zero-pressure zone at the wellhead of a water injection well according to claim 1, characterized in that, The bottom of the cylinder (1) is connected to an oil pipe.

5. The packer for establishing a zero-pressure zone at the wellhead of a water injection well according to claim 1, characterized in that, The external sealing unit includes an upper rubber sleeve (4.1) and a lower rubber sleeve (4.2) sleeved on the cylinder (1), and a spacer (5) sleeved on the cylinder (1) is provided between the upper rubber sleeve (4.1) and the lower rubber sleeve (4.2).

6. The packer for establishing a zero-pressure zone at the wellhead of a water injection well according to claim 5, characterized in that, The top end of the upper glue tube (4.1) contacts the bottom end of the outer cylinder (6), and the bottom end of the lower glue tube (4.2) contacts the bottom retaining ring (1.1) of the cylinder (1).

7. The packer for establishing a zero-pressure zone at the wellhead of a water injection well according to claim 1, characterized in that, The inner sealing unit includes an inner plug (3), an inner sealing ring (2) is fitted around the outer periphery of the inner plug (3), and guide posts (3.1) are provided on both sides of the top of the inner plug (3). The inner wall of the cylinder (1) is provided with a guide shoe to guide the movement of the guide post (3.1). A positive rotation groove (1.2) is opened on the bottom of the cylinder (1) of the guide shoe, and a positioning guide post (3.1) is provided at the bottom of the positive rotation groove (1.2).

8. The packer for establishing a zero-pressure zone at the wellhead of a water injection well according to claim 7, characterized in that, There are three inner sealing rings (2), and the three inner sealing rings (2) are distributed in parallel with equal spacing.

9. The packer for establishing a zero-pressure zone at the wellhead of a water injection well according to claim 7, characterized in that, The bottom of the swivel (8) is detachably threaded to the inner plug (3).

10. The packer for establishing a zero-pressure zone at the wellhead of a water injection well according to claim 1, characterized in that, The sealing unit is a pressure cap (7).

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