Built-in-solvent soluble bridge plug

Abstract

The present application relates to a built-in cosolvent soluble bridge plug, the bridge plug comprising a central pipe, a cosolvent inner cylinder, the cosolvent inner cylinder being sleeved on the inner wall of the central pipe, and a cosolvent storage space being formed between the contact surface of the two, the cosolvent being sealed and stored in the cosolvent storage space, the side wall of the central pipe being provided with a liquid inlet hole, the cosolvent inner cylinder being limited from moving out of the inner wall of the central pipe after being moved down along the inner wall of the central pipe under external force to communicate with the cosolvent storage space; the outer wall of the central pipe being sequentially provided from top to bottom with a rubber sleeve and a slip; the rubber sleeve being capable of swelling to seal the casing, and the slip being capable of anchoring on the wall of the casing to realize setting; the present application puts a soluble temporary plugging ball before fracturing construction, opens the internal liquid inlet channel of the soluble bridge plug while sealing the stratum after the temporary plugging ball is in place, and the cosolvent is dissolved in the liquid in the well, so that the soluble bridge plug is dissolved after the whole construction is completed, and the well is ensured to be smooth.

Description

Technical Field

[0001] This invention belongs to the field of downhole operation technology, and particularly relates to a soluble bridge plug with built-in co-solvent. Background Technology

[0002] Soluble bridge plugs possess the characteristic of self-dissolving. In recent years, the development of soluble bridge plugs and their supporting technologies in China has been rapid, becoming the main technology for shale gas and shale oil fracturing. The dissolution rate of soluble bridge plugs in the later stages of fracturing is mainly related to formation temperature and flux concentration. However, due to reservoir protection and rapid flowback requirements, flux cannot be injected into the wellbore during fracturing, or the effective contact time between the flux and the bridge plug is short. This results in very slow dissolution of the soluble bridge plug in the later stages, or even no dissolution at all, requiring drilling operations to clear the wellbore, thus negating the self-dissolving characteristic of soluble bridge plugs. Therefore, it is worth considering researching a soluble bridge plug with built-in flux, which can ensure rapid dissolution of the bridge plug after fracturing. Summary of the Invention

[0003] The technical problem solved by this invention is achieved through the following technical solution:

[0004] A built-in soluble bridge plug with a cosolvent, characterized in that: the bridge plug includes a central tube and a cosolvent inner cylinder, the cosolvent inner cylinder is sleeved on the inner wall of the central tube, and a cosolvent storage space is formed between the contact surfaces of the two, the cosolvent is sealed and stored in the cosolvent storage space, the side wall of the central tube is provided with a liquid inlet hole, and the cosolvent inner cylinder moves down along the inner wall of the central tube under external force until the liquid inlet hole communicates with the cosolvent storage space, the cosolvent inner cylinder is limited so that it cannot fall out of the inner wall of the central tube;

[0005] A rubber sleeve and a slip are arranged sequentially from top to bottom on the outer wall of the central tube; the rubber sleeve can expand to seal the sleeve, and the slip can be anchored to the sleeve wall to achieve a set seal.

[0006] Furthermore, it also includes a vertebral body, which is fixed to the outer wall of the central tube by a starting pin, and the vertebral body is located between the rubber sleeve and the slip, with the conical surface of the vertebral body embedded between the slip and the central tube.

[0007] Furthermore, the inner cylinder of the cosolvent is fixedly connected to the central tube by an inner cylinder shear pin.

[0008] Furthermore, a stepped structure is formed on the inner wall of the central tube. After the inner cylinder of the cosolvent moves down along the inner wall of the central tube to communicate with the liquid inlet and the cosolvent storage space, the inner cylinder of the cosolvent is limited by the stepped structure.

[0009] Furthermore, it also includes a release mechanism, which includes an adapter pusher and an adapter connector. One end of the adapter connector is fixedly connected to the outer wall of the central tube by a release scissor pin. The adapter pusher is sleeved on the adapter connector and can exert force on the rubber tube, cone, and slip.

[0010] Furthermore, the solubilizer, after melting, can dissolve the remaining structure of the bridge plug, excluding the discarding structure.

[0011] Furthermore, a base is fixedly provided on the outer wall of the central tube, and the base plays a limiting role for the locking mechanism.

[0012] Furthermore, the ports of the central tube and the cosolvent inner cylinder on the upstream side both form outwardly expanding inclined structures.

[0013] Furthermore, a number of card pieces are fixedly provided on the outer wall of the card.

[0014] Furthermore, it includes a rubber sleeve seat, which is installed on both sides of the rubber sleeve, and a rubber sleeve inner core is installed between the rubber sleeve and the central tube.

[0015] The advantages and positive effects of this invention are:

[0016] The soluble bridge plug of this invention places the co-solvent within a sealed space inside the soluble bridge plug. During the insertion and setting of the soluble bridge plug, the co-solvent remains in particulate form within the sealed space and does not have a solubilizing effect. Before fracturing operations, a soluble temporary plugging ball is inserted. After the temporary plugging ball is in place, it opens the internal liquid inlet channel of the soluble bridge plug while sealing the formation, allowing the co-solvent to dissolve in the well fluid. After the entire operation is completed, the dissolution of the soluble bridge plug is accelerated, ensuring unobstructed well flow. Attached Figure Description

[0017] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. However, it should be understood that these drawings are designed for illustrative purposes only and are not intended to limit the scope of the present invention. Furthermore, unless specifically indicated, these drawings are intended only to conceptually illustrate the structural construction described herein and are not necessarily drawn to scale.

[0018] Figure 1 This is a schematic diagram of the overall structure of a built-in cosolvent soluble bridge plug provided in an embodiment of the present invention; Detailed Implementation

[0019] First, it should be noted that the specific structure, features, and advantages of the present invention will be described in detail below by way of examples. However, all descriptions are for illustrative purposes only and should not be construed as limiting the present invention in any way. Furthermore, any single technical feature described or implied in the embodiments mentioned herein, or any single technical feature shown or implied in the accompanying drawings, can still be arbitrarily combined or deleted among these technical features (or their equivalents) to obtain more other embodiments of the present invention that may not be directly mentioned herein. Additionally, for the sake of simplifying the drawings, the same or similar technical features may be indicated only in one place in the same drawing.

[0020] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of this invention is usually placed during use. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0021] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other.

[0022] like Figure 1 As shown, this embodiment provides a built-in soluble bridge plug with a cosolvent. The bridge plug includes a central tube 14 and a cosolvent inner cylinder 3. The cosolvent inner cylinder 3 is sleeved on the inner wall of the central tube 14, and a cosolvent storage space is formed between the contact surfaces of the two. The cosolvent 5 is sealed and stored in the cosolvent storage space. In this embodiment, an annular cosolvent storage space can be opened on the outer wall of the cosolvent inner cylinder 3, and the cosolvent inner cylinder 3 on both sides of the cosolvent storage space is sealed with the central tube 14 by a sealing ring. The central tube 14 has a liquid inlet hole 14-1 on its side wall. When the cosolvent inner cylinder 3 moves down along the inner wall of the central tube 14 under external force until the liquid inlet hole 14-1 communicates with the cosolvent storage space, the cosolvent inner cylinder 3 is limited so that it cannot fall out of the inner wall of the central tube 14.

[0023] The outer wall of the central tube 14 is provided with a rubber cylinder 8 and a slip 12 from top to bottom; a number of slip particles 13 are fixed on the outer wall of the slip 12. The rubber cylinder 8 can expand to seal the sleeve, and the slip 12 can be anchored on the sleeve wall to achieve a set seal.

[0024] In addition, it also includes a cone body 9, which is fixed to the outer wall of the central tube 14 by a starting pin 11, and the cone body 9 is located between the rubber sleeve 8 and the slip 12, with the conical surface of the cone body 9 embedded between the slip 12 and the central tube 14.

[0025] Specifically, the inner cylinder of the cosolvent 3 is fixedly connected to the central tube 14 by the inner cylinder shear pin 10. A stepped structure is formed on the inner wall of the central tube 14. After the inner cylinder of the cosolvent 3 moves down along the inner wall of the central tube 14 to communicate with the liquid inlet 14-1 and the cosolvent storage space, the inner cylinder of the cosolvent 3 is limited by the stepped structure.

[0026] It also includes a release mechanism, which includes an adapter pusher 1 and an adapter connector 2. One end of the adapter connector 2 is fixedly connected to the outer wall of the central tube 14 by a release scissor 4. The adapter pusher 1 is sleeved on the adapter connector 2 and can exert force on the rubber tube 8, the cone 9, and the slip 12. A base 15 is also fixedly provided on the outer wall of the central tube, and the base plays a limiting role for the slip.

[0027] In addition, when installing the glue tube 8, a glue tube seat 6 is also included. The glue tube seat 6 is installed on both sides of the glue tube, and the glue tube inner core 7 is installed between the glue tube and the central tube 14. Accordingly, the glue tube 8, glue tube seat 6 and glue tube inner core 7 are all commercially available soluble products.

[0028] The cosolvent 5, after melting, can dissolve the remaining structure of the bridge plug, excluding the dropper structure and the card granules 13. Specifically, the cosolvent can be potassium chloride granules, and the remaining structure of the bridge plug can be made of magnesium-aluminum alloy.

[0029] In addition, when the inner cylinder 3 of the cosolvent moves down along the inner wall of the central tube 14, an external force can be applied by throwing a ball. In order to make the sealing ball better apply a sealing and sealing effect on the central tube 14 and the inner cylinder 3 of the cosolvent, the ports of the central tube 14 and the inner cylinder 3 of the cosolvent on the upstream side are both formed with outwardly expanding inclined structures.

[0030] Specifically, the glue cartridge 8 and the glue barrel inner core 7 are injected as one unit during the injection process. The locating granules 13 are embedded in the corresponding grooves of the locating granules 12 and are bonded with adhesive. The cosolvent inner cylinder 3 is inserted into the central tube 14 from the upper end. Before the cosolvent inner cylinder 3 is fully inserted into the central tube 14, solid granular cosolvent 5 is placed in the cosolvent storage space between the cosolvent inner cylinder 3 and the central tube 14. The inner cylinder shear pins 10 fix the cosolvent inner cylinder 3 to the central tube 14. The glue cartridge 8 and the cone... The cone 9 and the clasp 12 are sequentially inserted into the central tube 14 from the lower end of the central tube 14. The starting pin 11 fixes the cone 9 to the central tube 14. The base 15 is connected to the lower end of the central tube 14 by threads. The lower end of the adapter connector 2 is fitted onto the uppermost end of the central tube 14, and the upper end is connected to the corresponding setting tool by threads. The release scissor 4 connects and fixes the adapter connector 2 to the central tube 14. The lower end of the adapter push cylinder 1 is fitted onto the adapter connector 2, and the upper end is connected to the corresponding setting tool by threads.

[0031] As an example, in this embodiment, after the built-in solvent-soluble bridge plug is connected to the cable transmission setting tool, it is lowered to the designated position in the well. The setting tool is activated, and the adapter pusher 1 is pushed down. The adapter pusher 1 moves downward, causing the rubber sleeve seat 6 to squeeze the rubber sleeve 8. At the same time, it cuts the starting pin 11, causing the cone 9 to move downward, pushing the slips 12 to open, so that the rubber sleeve 8 and the well wall are sealed. At the same time, the slips 13 on the slips 12 are anchored on the casing wall, completing the entire setting. The adapter pusher 1 continues to apply downward force, cutting the release shear pin 4, so that the adapter connector 2 is separated from the central tube 14, completing the entire release. The cable transmission equipment, adapter connector 2 and adapter pusher 1 are then pulled out of the well. Before fracturing, a soluble temporary plugging ball is dropped into the wellbore. The plugging ball falls onto the upper end of the flux inner cylinder 3, sealing the channel inside the soluble bridge plug. Pressure is applied at the wellhead, and the inner cylinder shear pin 10 is cut off. The soluble temporary plugging ball and the flux inner cylinder 3 descend. The liquid in the wellbore enters through the inlet hole 14-1 of the central tube 14 and dissolves with the flux 5, producing a dissolving effect. After descending, the soluble temporary plugging ball falls onto the ball seat at the upper end of the central tube 14, blocking the channel inside the bridge plug and completing the formation isolation.

[0032] The above embodiments have provided a detailed description of the present invention, but the content described is only a preferred embodiment of the present invention and should not be considered as limiting the scope of the present invention. All equivalent variations and improvements made within the scope of the present invention should still fall within the patent coverage of the present invention.

Claims

1. A built-in-solubility-aid-soluble bridge plug, characterized in that: The bridge plug includes a central tube (14) and a cosolvent inner cylinder (3). The cosolvent inner cylinder (3) is sleeved on the inner wall of the central tube (14), and a cosolvent storage space is formed between the contact surfaces of the two. The cosolvent (5) is sealed and stored in the cosolvent storage space. The central tube (14) has a liquid inlet hole (14-1) on its side wall. When the cosolvent inner cylinder (3) moves down along the inner wall of the central tube (14) under external force until the liquid inlet hole (14-1) communicates with the cosolvent storage space, the cosolvent inner cylinder (3) is limited so that it cannot come out of the inner wall of the central tube (14). The outer wall of the central tube (14) is provided with a rubber sleeve (8) and a slip (12) from top to bottom; the rubber sleeve (8) can expand to seal the sleeve, and the slip (12) can be anchored on the sleeve wall to achieve a seat seal; The inner cylinder (3) of the cosolvent is fixedly connected to the central tube (14) by the inner cylinder shear pin (10); a stepped structure is formed on the inner wall of the central tube (14). After the inner cylinder (3) of the cosolvent moves down along the inner wall of the central tube (14) to the liquid inlet (14-1) and communicates with the cosolvent storage space, the inner cylinder (3) of the cosolvent is limited by the stepped structure.

2. The bridge plug with built-in solubility enhancing agent according to claim 1, wherein: It also includes a cone (9), which is fixed to the outer wall of the central tube (14) by a starting pin (11), and the cone (9) is located between the rubber sleeve (8) and the slip (12), with the conical surface of the cone (9) embedded between the slip (12) and the central tube (14).

3. The built-in co-solvent soluble bridge plug according to claim 2, characterized in that: It also includes a release mechanism, which includes an adapter pusher (1) and an adapter connector (2). One end of the adapter connector (2) is fixedly connected to the outer wall of the central tube (14) by a release scissor pin (4). The adapter pusher (1) is sleeved on the adapter connector (2), and the adapter pusher (1) can exert force on the rubber tube (8), the cone (9), and the slip (12).

4. The bridge plug with built-in solubility enhancing agent according to claim 3, wherein: The cosolvent (5) can dissolve the remaining structure of the bridge plug, excluding the discarding structure, after melting.

5. The bridge plug with built-in solubility enhancing agent according to claim 1, wherein: A base (15) is also fixed on the outer wall of the central tube, and the base plays a limiting role for the clasp.

6. The bridge plug with built-in solubility enhancing agent according to claim 1, wherein: The ports of the central tube (14) and the cosolvent inner cylinder (3) on the upstream side both form outwardly expanding inclined structures.

7. The bridge plug with built-in solubility enhancing agent according to claim 1, wherein: Several card pieces (13) are fixedly provided on the outer wall of the card.

8. The bridge plug with built-in solubility enhancing agent according to claim 1, wherein: It includes a rubber tube seat (6), which is installed on both sides of the rubber tube, and the rubber tube inner core (7) is installed between the rubber tube and the central tube (14).

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