Pressure balancing device and method for layered injection

Abstract

The application discloses a pressure balancing device and method for layered injection and production, and belongs to the technical field of oil production engineering. The device comprises a plurality of eccentric working barrels arranged on a tubing, a blind plug movably connected with the eccentric working barrels, a pressure guide pipe arranged in the blind plug, a conical inner dogging arranged at the top of the blind plug, a conical outer dogging matched with the conical inner dogging, the conical outer dogging arranged on the outer periphery of a fishing tool, a limiting structure a arranged at the bottom end of the conical outer dogging and fixed on the fishing tool, and a limiting structure b arranged above the conical outer dogging and fixed on the fishing tool. The device has the beneficial effects that the blind plug design can realize internal and external pressure balance, the fishing tool is added during pressure balance, the layered drainage tool can be ensured to be opened and fished out, the requirement of layered drainage and library building can be met, the operation cost of injection and production wells can be reduced, and the feasibility of layered drainage can be improved.

Description

Technical Field

[0001] This invention relates to a pressure balancing device and method for stratified injection and production, belonging to the field of oil production engineering technology. Background Technology

[0002] The development of existing gas storage facilities has entered a stage of fine-tuning. For wells with peripheral drainage and volume enhancement, the original tubing is often used for general drainage and oil production, which results in low production efficiency. If layered packers are used in conjunction with wireline-operated eccentric production controllers to adjust the production of each layer, blind plugs are often run to shut down the eccentric production controllers when a certain layer needs to be temporarily shut down. This approach can achieve temporary well-free sealing, which is beneficial for drainage of individual layers and system testing, but it now faces the following problems:

[0003] 1. During the sealing process, blind plugs are sometimes used. Sometimes the sealing time is too long, which causes the layer to become pressurized. Due to the large pressure difference between the inside and outside, the blind plug can often be retrieved by wire.

[0004] 2. Due to the eccentric structural design, when using manual blind plugs, it is often necessary to use an electric rotating retrieval tool to ensure that the retrieval tool is connected to the blind plug before retrieval can be achieved. This is inefficient and may even lead to the need to lift the pipe string, resulting in a large amount of ineffective work. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the purpose of this invention is to provide a pressure balancing device and method for stratified injection and extraction, ensuring that the stratification tool can be opened and retrieved, thus meeting the requirements for stratified drainage.

[0006] The technical solution of the present invention is: a pressure balancing device for stratified injection and production, comprising a plurality of eccentric working cylinders disposed on the tubing, a blind plug movably connected to the eccentric working cylinders, a pressure guiding pipe disposed inside the blind plug, a conical internal thread disposed at the top of the blind plug, a conical external thread engaging with the conical internal thread, the conical external thread being located on the outer periphery of the casting and retrieval tool, a limiting structure a fixed on the casting and retrieval tool being disposed at the bottom end of the conical external thread, and a limiting structure b fixed on the casting and retrieval tool being disposed above the conical external thread.

[0007] The bottom of the fishing tool is provided with a smooth end, and a tapered external thread is located above the smooth end.

[0008] The top of the pressure guiding tube is connected to the upper end face of the blind plug, and the bottom of the pressure guiding tube is connected to the bottom of the blind plug side.

[0009] The limiting structure a is a cuttable limiting structure.

[0010] The limiting structure b is a non-cuttable limiting structure.

[0011] The tubing is located inside the casing.

[0012] The blind plug and the eccentric working cylinder are connected by a flexible metal seal.

[0013] This invention also claims protection for a pressure balancing method for stratified injection and production, comprising the following steps:

[0014] Step 1: The wire vibrator drives the casting tool downward to strike the blind block pre-made on the eccentric working cylinder;

[0015] Step 2: Observe the changes in the reading of the suspension indicator connected to the wire vibrator during each impact;

[0016] Step 3: During the shock, the smooth end of the bottom of the throwing tool enters the blind block, and the limiting structure a pushes the blind block downward;

[0017] Step 4: After the limiting structure a moves down to contact the eccentric working cylinder, as the wire vibrator continues to vibrate, the limiting structure a breaks. At this time, the bottom of the pressure guiding tube inside the blind plug moves to the bottom outside the blind plug, the pressure guiding tube is open, and the breaking of the limiting structure a bears a large impact force. The reading of the suspension indicator will change significantly. The staff can determine that the blind plug has been opened by the change in this reading.

[0018] Step 5: After the injection and extraction process is completed, remove the blind plug.

[0019] The wire vibrator strikes the retrieval tool, causing the retrieval tool to move downward relative to the blind plug. The conical external teeth on the retrieval tool tightly engage with the conical internal teeth inside the blind plug. The wire vibrator is then lifted, and the blind plug is pulled out along with the wire vibrator.

[0020] Step Six: Insert a new blind plug. Specifically, assemble the internal thread of the safety connector with the external thread of the retrieval tool. Place the new blind plug over the outside of the safety connector and use a pin to fix the safety connector and the new blind plug. Insert the new blind plug into the eccentric working cylinder. Under the impact of the wire vibrator, the new blind plug passes through the guide ramp on the eccentric working cylinder and enters the eccentric working cylinder. The pin breaks under the shear force, and the working end of the wire vibrator is lifted, causing the safety connector to separate from the new blind plug. Then remove the safety connector and repeat steps one to five.

[0021] The beneficial effects of this invention are: by adopting a blind plugging design that can achieve internal and external pressure balance, and by adding a retrieval tool when the pressure is balanced, it can ensure that the stratified drainage tool can be opened and retrieved, thus meeting the needs of stratified drainage and reservoir construction, reducing the operating cost of injection and production wells, and improving the feasibility of stratified drainage. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the blind blockage in a closed state;

[0023] Figure 2 This is a diagram showing the blind blockage in its open state.

[0024] Figure 3 This is a diagram of the salvage tools.

[0025] Figure 4 This is a schematic diagram illustrating the application of the present invention;

[0026] Figure 5 This is a schematic diagram of the connection between the safety connector and the blind plug.

[0027] The following labels are used in the attached diagram: 1. Oil pipe, 2. Eccentric working cylinder, 3. Blind plug, 4. Conical internal thread, 5. Conical external thread, 6. Throwing and retrieval tool, 7. Limiting structure a, 8. Limiting structure b, 9. Pressure guide pipe, 10. Smooth end, 11. Casing, 12. Safety joint, 13. Pin. Detailed Implementation

[0028] 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.

[0029] 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.

[0030] 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.

[0031] 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.

[0032] The following is in conjunction with the appendix Figures 1-5 The present invention will be further described in detail below with reference to specific embodiments: the present application will be further described and illustrated by taking these embodiments as examples.

[0033] A pressure balancing device for stratified injection and production includes several eccentric working cylinders 2 mounted on an oil pipe 1, blind plugs 3 movably connected to the eccentric working cylinders 2, pressure guiding pipes 9 inside the blind plugs 3, and a conical internal thread 4 at the top of the blind plugs 3. A conical external thread 5 mates with the conical internal thread 4. The conical external thread 5 is located on the outer periphery of a retrieval tool 6, with a flat top and a downwardly inclined bottom. The conical internal thread 4 has a downwardly inclined top and a flat bottom. When subjected to external force... The conical external thread 5 can move downward relative to the conical internal thread 4. The top planes of the conical external thread 5 and the conical internal thread 4 fit together, forming an engaged state. When pulled upward, the fitting planes prevent the conical external thread 5 from easily disengaging, i.e., it will not easily move upward relative to the conical internal thread 4. In this way, the blind plug 3 can be pulled upward. The bottom of the conical external thread 5 is provided with a limiting structure a7 fixed to the throwing tool 6, and the top of the conical external thread 5 is provided with a limiting structure b8 fixed to the throwing tool 6. The limiting structure a7 is a cuttable limiting structure, which can push the blind plug downward as a whole. When the limiting structure a7 is cut off, the conical external thread 5 can enter the conical internal thread 4. The limiting structure b8 is a non-cuttable limiting structure, used to control the stroke of the conical external thread 5 relative to the conical internal thread 4.

[0034] The bottom of the casting tool 6 is provided with a smooth end 10, and the conical external toothed buckle 5 is located above the smooth end 10. The smooth end 10 enters the blind plug 3 first, which plays a guiding role and can open the blind plug 3 first, so as to facilitate the subsequent entry of the conical external toothed buckle 5.

[0035] The top of the pressure guiding pipe 9 is connected to the upper end face of the blind plug 3, and the bottom of the pressure guiding pipe 9 is connected to the bottom side of the blind plug 3. When the blind plug 3 just enters the eccentric working cylinder 2, the bottom of the pressure guiding pipe 9 is sealed by the inner wall of the eccentric working cylinder 2 and cannot conduct. When the blind plug 3 moves down to the position, the bottom of the pressure guiding pipe 9 moves to the bottom of the eccentric working cylinder 2 and achieves communication with the top.

[0036] The tubing 1 is located inside the casing 11 and is connected to the downhole tools to ensure the connection between the reservoir and the surface production system.

[0037] The blind plug 3 and the eccentric working cylinder 2 are connected by a flexible metal seal. After the pressure is connected, the blind plug 3 can be successfully retrieved by lifting the steel wire.

[0038] A pressure balancing method for stratified injection and production includes the following steps:

[0039] Step 1: The wire vibrator drives the fishing tool 6 to strike the blind plug 3 prefabricated on the eccentric working cylinder 2 downwards;

[0040] Step 2: Observe the changes in the reading of the suspension indicator connected to the wire vibrator during each impact;

[0041] Step 3: During the shock, the smooth end 10 at the bottom of the throwing tool 6 enters the blind plug 3, and the limiting structure a7 pushes the blind plug 3 downward;

[0042] Step 4: After the limiting structure a7 moves down to contact the eccentric working cylinder 2, the limiting structure a7 breaks as the wire vibrator continues to vibrate. At this time, the bottom of the pressure guiding pipe 9 inside the blind plug 3 moves to the bottom outside the blind plug 3, the pressure guiding pipe 9 is open, the limiting structure a7 breaks and bears a large impact force, the reading of the suspension indicator will change significantly, and the staff can determine that the blind plug 3 has been opened by the change in the reading.

[0043] Step 5: After the injection and collection process is completed, retrieve the blind plug 3. The wire vibrator strikes the retrieval tool 6, causing the retrieval tool 6 to move downward relative to the blind plug 3. The conical external teeth 5 on the retrieval tool 6 tightly engage with the conical internal teeth 4 inside the blind plug 3. The wire vibrator is then lifted, and the blind plug 3 is pulled out along with the wire vibrator.

[0044] Step Six: Lower the new blind plug 3. Specifically, assemble the internal thread of the safety connector 12 with the external thread of the retrieval tool 6. The limiting structure a7 has been cut off, so the internal thread of the safety connector 12 and the external thread of the retrieval tool 6 can be directly assembled. The new blind plug 3 is fitted onto the outside of the safety connector 12. The safety connector 12 and the new blind plug 3 are fixed by the pin 13. The new blind plug 3 is lowered into the eccentric working cylinder 2. Under the impact of the wire vibrator, the new blind plug 3 enters the eccentric working cylinder 2 through the guide ramp on the eccentric working cylinder 2. The pin 13 breaks under the shear force, and the working end of the wire vibrator is lifted, causing the safety connector 12 to separate from the new blind plug 3. Then, remove the safety connector 12 and repeat steps one to five.

[0045] 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 pressure balancing device for stratified injection and production, characterized in that, It includes several eccentric working cylinders (2) set on the oil pipe (1), a blind plug (3) movably connected to the eccentric working cylinders (2), a pressure guide pipe (9) inside the blind plug (3), a conical internal thread (4) at the top of the blind plug (3), a conical external thread (5) cooperating with the conical internal thread (4), the conical external thread (5) being located on the outer periphery of the fishing tool (6), a limiting structure a (7) fixed on the fishing tool (6) at the bottom of the conical external thread (5), and a limiting structure b (8) fixed on the fishing tool (6) above the conical external thread (5). The top of the pressure guiding tube (9) is connected to the upper end face of the blind plug (3), and the bottom of the pressure guiding tube (9) is connected to the bottom side of the blind plug (3); The limiting structure a (7) is a cuttable limiting structure; The limiting structure b (8) is a non-cuttable limiting structure.

2. The pressure balancing device for stratified injection and production according to claim 1, characterized in that, The bottom of the fishing tool (6) is provided with a smooth end (10), and the conical external tooth (5) is located above the smooth end (10).

3. The pressure balancing device for stratified injection and production according to claim 1, characterized in that, The oil pipe (1) is located inside the casing (11), and a through hole is opened on the oil pipe.

4. The pressure balancing device for stratified injection and production according to claim 1, characterized in that, The blind plug (3) and the eccentric working cylinder (2) are connected by a flexible metal seal.

5. The pressure balancing method for stratified injection and extraction using the balancing device as described in claim 2, characterized in that, Includes the following steps: Step 1: The wire vibrator drives the fishing tool (6) to vibrate downwards against the blind plug (3) prefabricated on the eccentric working cylinder (2); Step 2: Observe the changes in the reading of the suspension indicator connected to the wire vibrator during each impact; Step 3: During the shock, the smooth end (10) at the bottom of the throwing tool (6) enters the blind plug (3), and the limiting structure a (7) pushes the blind plug (3) down; Step 4: After the limiting structure a (7) moves down to contact the eccentric working cylinder (2), as the wire vibrator continues to vibrate, the limiting structure a (7) breaks. At this time, the bottom of the pressure guide tube (9) inside the blind plug (3) moves to the bottom outside the blind plug (3), the pressure guide tube (9) is connected, the limiting structure a (7) breaks and bears a large impact force, the reading of the suspension indicator will change significantly, and the staff can determine that the blind plug (3) has been opened by the change in the reading. Step 5: After the injection and collection process is completed, remove the blind plug (3).

6. The balancing method according to claim 5, characterized in that, The specific process of retrieving the blind plug (3) is as follows: the wire vibrator strikes the retrieval tool (6), causing the retrieval tool (6) to move down relative to the blind plug (3). The conical external teeth (5) on the retrieval tool (6) and the conical internal teeth (4) inside the blind plug (3) are tightly engaged. The wire vibrator is then lifted up, and the blind plug (3) is lifted out along with the wire vibrator.

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