Soluble bridge plug with hydrotropy function and bridge plug deblocking method

Abstract

The invention belongs to the technical field of oil and gas field downhole tools, and particularly relates to a soluble bridge plug with a dissolution assisting function and a bridge plug deblocking method. The soluble bridge plug with the dissolution assisting function comprises a center pipe, an adapter connecting rod is arranged at the top of the center pipe, a dissolution assisting channel is formed in the adapter connecting rod, the space above the adapter connecting rod is communicated with an inner cavity of the center pipe through the dissolution assisting channel, and when the soluble bridge plug encounters resistance or clamping in the well entering process, the soluble bridge plug can enter a well through the dissolution assisting channel. And a cosolvent is pumped to the underground, so that the cosolvent can enter the inner cavity of the central pipe through the hydrotropy channel, and the time for releasing the releasing tool to release is shortened.

Description

Technical Field

[0001] The invention belongs to the technical field of downhole tools in oil and gas fields, and in particular relates to a soluble bridge plug with a dissolution-aiding function and a bridge plug unblocking method. Background Art

[0002] At present, in the process of oil and gas well operation, soluble bridge plugs have been widely used for formation isolation. The use of bridge plugs for formation isolation can effectively achieve staged fracturing.

[0003] With the increase in the drilling depth of oil and gas wells, the requirements for soluble bridge plugs are becoming higher and higher. For example, in the operation process in some areas, the tight oil reservoir is as high as 6000-8000m, and the depth of some blocks is even more than 8000m. In addition, there are reservoir characteristics such as ultra-high temperature of 150℃-200℃ and high pressure of 70-100MPa. Large liquid volume, large displacement and high sand ratio construction are required, which can easily cause sand settling in the wellbore and deformation of the casing, resulting in the soluble bridge plug being blocked or stuck in advance during the lowering and sealing process.

[0004] After the soluble bridge plug encounters resistance or jam in advance, it is necessary to use a solvent to dissolve the soluble bridge plug to achieve dissolution and release of the soluble bridge plug. However, during the process of the soluble bridge plug entering the well, due to the limitation of its structure, the top of the soluble bridge plug is in a closed state, and the wellbore liquid can only reach the top of the soluble bridge plug and the outer wall of the soluble bridge plug, and cannot enter the inside of the soluble bridge plug. Therefore, the contact area between the soluble bridge plug and the wellbore liquid is small, and the soluble bridge plug can only be self-dissolved at a normal dissolution rate by relying on the wellbore liquid, so it takes a long time to achieve dissolution and release of the soluble bridge plug. In this environment, it is bound to cause a long period of ineffective production time, resulting in the shutdown of ground pump trucks and other equipment and facilities, and personnel, resulting in huge production waste and cost. Summary of the invention

[0005] In view of the technical problems mentioned above, the present invention aims to provide a soluble bridge plug with a dissolution-aiding function, which can accelerate the dissolution rate of the soluble bridge plug when the soluble bridge plug encounters resistance or jamming.

[0006] The present invention also provides a bridge plug unblocking method, which can accelerate the dissolution rate of the soluble bridge plug when the soluble bridge plug encounters obstruction or jamming.

[0007] According to the present invention, a soluble bridge plug with a dissolution-aiding function is provided, comprising a central tube, an adapter connecting rod is arranged on the top of the central tube, and a dissolution-aiding channel is arranged on the adapter connecting rod, the dissolution-aiding channel connects the space above the adapter connecting rod with the inner cavity of the central tube, when the soluble bridge plug encounters obstruction or gets stuck during entering the well, a dissolution-aiding agent is pumped downhole, so that the dissolution-aiding agent can enter the inner cavity of the central tube through the dissolution-aiding channel, thereby shortening the time for dissolving and unblocking.

[0008] In a preferred embodiment, the adapter connecting rod comprises a rod-shaped portion and a connecting portion which are coaxially fixed in sequence from top to bottom, the connecting portion is connected to the central tube, and the dissolution-aiding channel is arranged on the connecting portion.

[0009] In a preferred embodiment, the outer diameter of the connecting portion is greater than the outer diameter of the rod-shaped portion.

[0010] In a preferred embodiment, the inner wall of the connecting portion contacts the outer wall of the central tube.

[0011] In a preferred embodiment, the connecting portion includes a connecting section and a transition section, the transition section is located between the rod-shaped portion and the connecting section, the transition section is located above the central tube, and the dissolution-aiding channel is arranged on the transition section.

[0012] In a preferred embodiment, a plurality of the dissolution-assisting channels are evenly arranged on the transition section along the circumferential direction, and the central axis of the dissolution-assisting channel and the central axis of the adapter connecting rod are inclined to each other.

[0013] In a preferred embodiment, the outer wall of the connecting portion contacts the inner wall of the central tube.

[0014] In a preferred embodiment, the connecting portion includes a connecting section and a transition section, the transition section is located between the rod-shaped portion and the connecting section, the transition section is located above the central tube, and the dissolution-aiding channel is arranged on the transition section and the connecting section.

[0015] In a preferred embodiment, the dissolution-aiding channel includes a first channel and a second channel, wherein the first channel is located in the transition section and is perpendicular to the central axis of the adapter connecting rod, and the second channel is coaxially arranged in the connecting section and is connected to the first channel.

[0016] According to the present invention, a method for removing obstruction from a bridge plug is also provided. When a soluble bridge plug with a dissolution-aiding function provided by the present invention encounters obstruction or gets stuck during insertion into a well, a dissolution-aiding agent is pumped into the well, thereby allowing the dissolution-aiding agent to enter the inner cavity of the central pipe through a dissolution-aiding channel, thereby dissolving the soluble bridge plug and completing the removal of obstruction.

[0017] Compared with the prior art, the advantages of the present application are as follows.

[0018] The present invention provides a dissolution-promoting channel on the adapter connecting rod, which connects the top of the soluble bridge plug with the inner cavity of the soluble bridge plug. When the soluble bridge plug encounters obstruction or gets stuck during the process of entering the well, for example, when the soluble bridge plug encounters obstruction due to sand accumulation in the wellbore, especially in a long horizontal well section, a variety of methods can be used to remove the obstruction.

[0019] For example, the dissolution-aiding channel can be used for liquid circulation to achieve blockage removal by circulating drilling fluid.

[0020] The dissolution channel can also be used for sand flushing and well washing, or by pumping the dissolution agent into the well, the dissolution agent and drilling fluid can enter the cavity of the soluble bridge plug, accelerate the dissolution of the soluble bridge plug, improve the effectiveness of the construction, and ensure the smooth progress of the construction. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The present invention will be described below with reference to the accompanying drawings.

[0022] Figure 1 A schematic diagram showing a first embodiment of a soluble bridge plug with a dissolution-aiding function according to the present invention;

[0023] Figure 2 A schematic diagram showing a second embodiment of a soluble bridge plug with a dissolution-promoting function according to the present invention;

[0024] Figure 3 A schematic diagram showing the connection between a first embodiment of a soluble bridge plug with a dissolution-assisting function according to the present invention and an adapter push cylinder;

[0025] Figure 4 A schematic diagram showing the connection between a second embodiment of the soluble bridge plug with a dissolution-assisting function according to the present invention and an adapter push cylinder is shown.

[0026] In the figure:

[0027] 1. Center tube; 101. Inner cavity; 2. Upper slip; 3. Upper anchoring tooth; 4. Upper cone; 5. Upper metal support ring; 6. Rubber cylinder; 7. Lower rubber cylinder protection ring; 8. Lower metal support ring; 9. Lower cone; 10. Lower slip; 11. Lower anchoring tooth; 12. Guide shoe; 14. Adapter connecting rod; 141. Rod-shaped part; 142. Connecting part; 143. Connecting section; 144. Transition section; 15. Adapter push cylinder; 16. Dissolution channel; 161. First channel; 162. Second channel; 17. Shear pin; 100. Soluble bridge plug.

[0028] In the present application, all drawings are schematic drawings, which are only used to illustrate the principles of the present invention and are not drawn according to the actual scale. DETAILED DESCRIPTION

[0029] The present invention will be described below with reference to the accompanying drawings.

[0030] It should be noted that, in the present application, the direction of the soluble bridge plug 100 according to the present invention close to the wellhead after entering the well is described as "top", "up", "front" or similar terms, and the direction away from the wellhead is described as "bottom", "down", "back" or similar terms.

[0031] In the prior art, if the bridge plug encounters resistance or gets stuck during the lowering process, and the bridge plug cannot be lifted up, the only option is to wait for the soluble bridge plug to slowly dissolve under the immersion of drilling fluid. Due to the limitation of the bridge plug structure in the prior art, before the bridge plug is released normally, the adapter connecting rod will seal the top of the bridge plug, and the drilling fluid cannot enter the interior of the bridge plug, which reduces the contact surface between the drilling fluid and the bridge plug, and the bridge plug dissolves slowly, which delays the construction time.

[0032] Embodiment 1:

[0033] like Figure 1 and Figure 3 As shown, a soluble bridge plug 100 with a dissolution-assisting function is shown, including a central tube 1, an adapter connecting rod 14 is arranged on the top of the central tube 1, and a dissolution-assisting channel 16 is arranged on the adapter connecting rod 14, and the dissolution-assisting channel 16 connects the space above the adapter connecting rod 14 with the inner cavity 101 of the central tube 1.

[0034] Under this setting of the present embodiment, in addition to the conventional bridge plug unblocking method in the prior art, the present embodiment can also use other methods for unblocking. When the soluble bridge plug encounters obstruction or gets stuck during entering the well, the dissolution channel 16 can be used for drilling fluid circulation to complete the circulation unblocking. If the drilling fluid circulation cannot complete the unblocking work, the solvent can be pumped downhole to mix the solvent with the drilling fluid in the well and enter the inner cavity 101 of the central pipe 1 through the dissolution channel 16. In this way, the contact area between the solvent and the drilling fluid and the soluble bridge plug 100 can be increased, and the time for dissolving and unblocking can be shortened.

[0035] It is easy to understand that the soluble bridge plug 100 is made of soluble material, which is a prior art and not the technical point of the present invention. A solvent is a material that can promote the dissolution of the soluble material, and the specific composition of this material is not the technical point of the present invention and will not be repeated here.

[0036] In a specific embodiment, the adapter connecting rod 14 includes a rod-shaped portion 141 and a connecting portion 142 which are coaxially fixed from top to bottom, the connecting portion 142 is connected to the central pipe 1, and the dissolution-aiding channel 16 is arranged on the connecting portion 142. During operation, the rod-shaped portion 141 is connected to a downhole tool for controlling the upper body or the lower body of the soluble bridge plug 100.

[0037] In this embodiment, the outer diameter of the connecting portion 142 is greater than the outer diameter of the rod-shaped portion 141. In the actual working process, the central tube 1 is axially abutted against the adapter push tube 15, and the adapter connecting rod 14 is located inside the adapter push tube 15. Since the outer diameter of the connecting portion 142 is greater than the outer diameter of the rod-shaped portion 141, an annulus exists between the rod-shaped portion 141 and the adapter push tube 15, which facilitates the flow of liquid and enables the fluid to enter the inner cavity 101 of the central tube 1 through the dissolution-aiding channel 16.

[0038] Furthermore, in this embodiment, the inner wall of the connecting portion 142 contacts the outer wall of the central tube 1. That is, the connecting portion 142 is coaxially sleeved on the outside of the central tube 1. Figure 1 As shown, the connection portion 142 is fixedly connected to the central pipe 1 via a shear pin 17 .

[0039] In a specific embodiment, the connecting portion 142 is configured as a cylinder with one end closed and the other end open, the closed end of the connecting portion 142 is connected to the rod-shaped portion 141, and the open end of the connecting portion 142 is used to sleeve the central tube 1. Further, the connecting portion 142 includes a connecting section 143 and a transition section 144 that are coaxially fixedly connected, the transition section 144 is located between the rod-shaped portion 141 and the connecting section 143, and the transition section 144 is arranged at the upper end of the connecting section 143, that is, the transition section 144 is the closed end of the connecting portion 142. After the connecting portion 142 is sleeved on the central tube 1, the transition section 144 is located above the central tube 1, and the dissolution-aiding channel 16 is arranged on the transition section 144.

[0040] In this embodiment, a plurality of dissolution-assisting channels 16 are evenly arranged along the circumferential direction on the transition section 144. The central axis of the dissolution-assisting channel 16 is inclined to the central axis of the adapter connecting rod 14. Through this arrangement, the upper end of the dissolution-assisting channel 16 can be communicated with the annulus between the adapter connecting rod 14 and the adapter push cylinder 15, and the lower end of the dissolution-assisting channel 16 can be communicated with the inner cavity 101 of the central pipe 1.

[0041] Embodiment 2:

[0042] like Figure 2 and Figure 4 , which shows a schematic diagram of a second embodiment of a soluble bridge plug 100 with a dissolution-promoting function. In this embodiment, the structure of the connecting portion 142 is different from that in the first embodiment, and the remaining structures can refer to the first embodiment. The difference is that in this embodiment, the outer wall of the connecting portion 142 contacts the inner wall of the central tube 1, that is, the inner wall of the central tube 1 contacts the outer wall of the connecting portion 142.

[0043] Specifically, the connecting portion 142 includes a connecting section 143 and a transition section 144 which are coaxially arranged, and the transition section 144 is located between the rod-shaped portion 141 and the connecting section 143. The upper portion of the connecting section 143 is arranged in a truncated cone shape, and the radius gradually decreases from top to bottom, and the radius of the upper end of the connecting section 143 is equal to the radius of the transition section 144. The radius of the transition section 144 is greater than the radius of the rod-shaped portion 141.

[0044] After the connecting portion 142 is fixedly connected to the central tube 1 , the transition section 144 is located above the central tube 1 , and the dissolution-aiding channel 16 is arranged on the transition section 144 and the connecting section 143 .

[0045] In a preferred embodiment, the dissolution-aiding channel 16 includes a first channel 161 and a second channel 162, the first channel 161 is located in the transition section 144, and the first channel 161 is perpendicular to the central axis of the adapter connecting rod 14, the second channel 162 is coaxially arranged in the connecting section 143, and the second channel 162 is connected to the first channel 161, and the connection point between the first channel 161 and the second channel 162 is located at the midpoint of the first channel 161.

[0046] Embodiment three:

[0047] This embodiment provides a specific structure of a soluble bridge plug 100 .

[0048] like Figure 1 As shown, the soluble bridge plug 100 includes a central tube 1, on the outer wall of the central tube 1, an upper slip 2, an upper cone 4, an upper metal support ring 5, a rubber tube 6, a lower rubber tube protection ring 7, a lower metal support ring 8, a lower cone 9, a lower slip 10 and a guide shoe 12 are coaxially arranged in sequence from top to bottom. An upper anchoring tooth 3 is inlaid on the outer wall of the upper slip 2, and a lower anchoring tooth 11 is inlaid on the outer wall of the lower slip 10. The upper end of the upper slip 2 is axially abutted against the central tube 1, so that the upper slip 2 cannot move upward relative to the central tube 1. The guide shoe 12 is fixedly connected to the central tube 1 by threaded connection.

[0049] Combination Figure 3 As shown, the lower end of the adapter push tube 15 is axially abutted against the upper slip 2, and the adapter connecting rod 14 is fixedly connected to the center pipe 1 through the shear pin 17. When setting is required, the adapter connecting rod 14 moves upward relative to the adapter push tube 15, and the adapter connecting rod 14 drives the center pipe 1 and the guide shoe 12 to move upward relative to the adapter push tube 15 and the upper slip 2, so that the upper slip 2, the upper cone 4, the upper metal support ring 5, the rubber cylinder 6, the lower rubber cylinder protection ring 7, the lower metal support ring 8, the lower cone 9, and the lower slip 10 are mutually axially compressed to achieve radial expansion, thereby achieving setting. After the setting is completed, the adapter connecting rod 14 continues to move upward relative to the adapter push tube 15 to cut the shear pin 17, thereby completing the release.

[0050] In another embodiment, the adapter connecting rod 14 can also be connected to the central tube by a threaded connection. In this arrangement, the purpose of controlling the loss of the hand is achieved by controlling the strength of the threaded connection.

[0051] In a specific embodiment, the bridge plug setting method is as follows.

[0052] Step 1: Within 48 hours before the soluble bridge plug 100 is lowered, use a wellbore gauge of corresponding size or slightly larger size to clear the well or simulate pumping.

[0053] Step 2: After the soluble bridge plug 100 is installed at the lower end of the adapter connecting rod 14, the operation is kept as continuous as possible from the insertion of the soluble bridge plug 100 to the fracturing.

[0054] The process of connecting the soluble bridge plug 100 with the adapter connecting rod 14 is as follows:

[0055] The adapter link 14 is inserted from the top of the soluble bridge plug 100 and aligned with the hole of the shear pin 17 at the top of the soluble bridge plug 100;

[0056] Align and tighten the holes on the adapter connecting rod 14 and the shear pins 17 of the soluble bridge plug 100 with the special shear pins 17;

[0057] Install the limit pin (not shown in the figure), and make sure the pin is installed in the limit slot (not shown in the figure);

[0058] Connect the conversion joint (not shown) until there is no gap between the adapter push cylinder 15 and the soluble bridge plug 100;

[0059] Install no less than four M8 stop pins (not shown) of the conversion joint from the hole (not shown) of the adapter push tube 15.

[0060] In another embodiment, the adapter connecting rod 14 is connected to the central tube 1 by threaded connection, as follows:

[0061] The adapter connecting rod 14 is screwed to the central tube 1 through the thread;

[0062] Install the limit pin (not shown in the figure), and make sure the pin is installed in the limit slot (not shown in the figure);

[0063] Connect the conversion joint (not shown) until there is no gap between the adapter push cylinder 15 and the soluble bridge plug 100;

[0064] Install no less than four M8 stop pins (not shown) of the conversion joint from the hole (not shown) of the adapter push tube 15.

[0065] Step 3: Under normal circumstances, the entry speed of the vertical section is controlled at 50-70m / min, and the maximum entry speed is 70m / min. Under normal circumstances, the entry speed of the horizontal section is controlled at 35-40m / min, and the maximum entry speed is 50m / min.

[0066] After the soluble bridge plug 100 is lowered into place, it starts to be set, and the power source for setting can be provided by a hydraulic setting tool equipped with a continuous tubing or a cable gunpowder setting tool.

[0067] The upper part of the adapter push tube 15 is threadedly connected to the outer sleeve of the setting tool (not shown in the figure), and the lower part is axially abutted against the upper slip 2. The top of the adapter connecting rod 14 is threadedly connected to the inner sleeve of the setting tool, and the lower part of the adapter connecting rod 14 is connected to the central pipe 1. During the setting process, the adapter connecting rod 14 and the setting tool remain relatively stationary, and the adapter push tube 15 pushes the upper slip 2 to produce relative displacement.

[0068] The setting state is: when the initial force is relatively small, the upper metal support ring 5 and the lower metal support ring 8 of the soluble bridge plug 100 are first forced to open, and the rubber sleeve 6 begins to be compressed.

[0069] As the thrust increases, the upper slip 2 and the lower slip 10 are gradually opened, the pins connecting the upper cone 4 and the lower cone 9 with the central tube 1 are sheared off, and the rubber cylinder 6 continues to be squeezed and enlarged.

[0070] As the thrust increases, the upper slip 2 and the lower slip 10 are fully opened. Under the extrusion pressure, the upper slip 2 and the lower slip 10 expand radially along the upper cone 4 and the lower cone 9 respectively, and are gradually pressed onto the wall of the sleeve (not shown in the figure), and the rubber cylinder 6 is compressed to completely seal the sleeve.

[0071] When the thrust gradually increases and reaches the breaking force of the shear pin 17 or the connecting thread connecting the adapter connecting rod 14 and the center pipe 1, the adapter connecting rod 14 is separated from the center pipe 1. At this time, the upper slip 2 and the lower slip 10 are completely bitten and locked on the casing, and the rubber tube 6 is squeezed into a surface shape and sealed with the casing, thereby realizing the external sealing of the soluble bridge plug 100 and the casing.

[0072] Step 4: 30 minutes before fracturing, the soluble ball is placed on the ball seat inside the top of the soluble bridge plug 100 to achieve the seal between the soluble bridge plug 100 and the inside of the casing. Pumping is required immediately after the ball is placed. When the pumping liquid volume difference is 10m 3 When the casing volume of the stuck fracturing layer is reached, the pumping displacement is increased from 3 to 4 m 3 / min down to 1.5~2m 3 / min, fracturing after the ball is seated; the three steps of ball dropping, pumping and fracturing are performed continuously.

[0073] In a preferred embodiment, at least two rows of upper anchor teeth 3 are evenly distributed on the upper slip 2, and both the upper slip 2 and the upper anchor teeth 3 are made of high-strength ceramic particles. In this embodiment, the upper anchor teeth 3 use smaller high-strength ceramic particles, preferably with a size of 8×5mm or 9.5×7.5mm. Through this arrangement, the insoluble matter left in the well after dissolution is less than 1%, achieving the effect of facilitating the dissolution of the bridge plug.

[0074] In a preferred embodiment, at least three rows of lower anchor teeth 11 are evenly distributed on the lower slip 10, and both the lower slip 10 and the lower anchor teeth 11 are made of high-strength ceramic particles. In this embodiment, the lower anchor teeth 11 use smaller high-strength ceramic particles, preferably with a size of 8×5mm or 9.5×7.5mm. Through this arrangement, the insoluble matter left in the well after dissolution is less than 2%, achieving the effect of facilitating the dissolution of the bridge plug.

[0075] In a preferred embodiment, the central pipe 1 and the guide shoe 12 are made of a soluble magnesium alloy. In this embodiment, the soluble magnesium alloy material includes magnesium, zinc, aluminum, nickel, and copper, and the mass percentage of each component is: magnesium>85%, zinc 2-5%, aluminum 2-4%, nickel 1-3%, and copper 1-3%. The soluble magnesium alloy material provided in this embodiment is combined with the structure of the soluble bridge plug 100, so that the soluble bridge plug 100 can withstand a pressure of up to 70MPa and a temperature range of 0℃~200℃, and can achieve pressure bearing, rapid dissolution, and complete dissolution 6-10 days after construction in a complex wellbore environment.

[0076] In a preferred embodiment, the soluble magnesium alloy material further comprises neodymium and / or cerium, wherein the mass percentage of neodymium is 0-2%, and the mass percentage of cerium is 0-2%.

[0077] It is easy to understand that the present embodiment only provides a structure of a soluble bridge plug 100, which is used to illustrate that the adapter connecting rod 14 with the dissolution-aiding channel 16 provided by the present invention can be used for the soluble bridge plug 100, but is not used to limit the structure of the soluble bridge plug 100. As long as the remaining bridge plugs in the prior art include the adapter connecting rod 14 provided by the present invention, they should all be within the protection scope of the present invention.

[0078] Embodiment 4:

[0079] In one embodiment of the present invention, a method for removing obstruction from a bridge plug is provided. When a soluble bridge plug 100 with a dissolution-aiding function provided by the present invention is blocked or stuck during entry into a well, a dissolution-aiding agent is pumped into the well, so that the dissolution-aiding agent enters the inner cavity of the central pipe 1 through the dissolution-aiding channel 16, dissolving the soluble bridge plug 100, accelerating the dissolution rate of the soluble bridge plug 100, and completing the removal of obstruction.

[0080] Furthermore, if a protrusion occurs during the setting process of the soluble bridge plug 100, the following measures can be taken to achieve the purpose of cyclic dissolution, such as:

[0081] When the soluble bridge plug 100 encounters an obstruction before reaching the predetermined position, liquid can be pumped from the surface into the well to flush the wellbore through the dissolution-aiding channel 16 until the obstruction point is passed;

[0082] When the soluble bridge plug 100 is pulled up and stuck after encountering resistance, it is determined whether the conditions for on-site sealing are met according to the process requirements. If the construction requirements are met, it is directly sealed. If the soluble bridge plug 100 needs to be processed, high-concentration brine or acid solution needs to be pumped into the dissolution-aiding channel 16 of the soluble bridge plug 100 to achieve drilling-free and rapid dissolution of the soluble bridge plug 100.

[0083] In a preferred embodiment, if the site is complicated and normal running cannot be guaranteed, after the soluble bridge plug 100 is taken out and cleared, a smaller soluble bridge plug 100 can be run in according to the wellbore conditions. If the soluble bridge plug 100 encounters resistance during running, the cable is pulled up, the running speed is reduced, and the plug is run again. If the same position encounters resistance again, the cable is pulled out, the well clearing gauge is run in to clear the well, and if the soluble bridge plug 100 is stuck during running, the cable is pulled up to the safe tension that the cable can withstand. If the soluble bridge plug 100 cannot be lifted up to loosen it, a high concentration (10-15%) potassium chloride aqueous solution or 5-15% hydrochloric acid, potassium chloride aqueous solution or acid solution is transported to the inside of the soluble bridge plug 100 through the dissolution-aiding channel 16, so as to quickly dissolve the soluble bridge plug 100. After the soluble bridge plug 100 is dissolved or loosened, the pumping pipe string is taken out for inspection. If the soluble bridge plug 100 is set midway or ignition is lost during the lowering process, high concentration potassium chloride or 5-15% hydrochloric acid can be pumped in to dissolve the soluble bridge plug 100. After the dissolution, the plug is tested, the powder and debris produced by the dissolution are flushed into the lower part, and a new soluble bridge plug 100 is pumped again.

[0084] In the description of the present invention, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0085] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0086] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0087] Finally, it should be noted that the above is only a preferred embodiment of the present invention and does not constitute any limitation to the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for a person skilled in the art to modify the technical solutions described in the aforementioned embodiments or to replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A soluble bridge plug with a dissolution-aiding function, characterized in that: The invention comprises a central tube (1), an adapter connecting rod (14) is arranged at the top of the central tube (1), and a dissolution-aiding channel (16) is arranged on the adapter connecting rod (14), wherein the dissolution-aiding channel (16) connects the space above the adapter connecting rod (14) with the inner cavity of the central tube (1), and when the soluble bridge plug encounters an obstruction or a jam during entering the well, a dissolution-aiding channel is pumped into the well, so that the dissolution-aiding channel (16) can enter the inner cavity of the central tube (1), thereby shortening the time for dissolving and unblocking.

2. The soluble bridge plug with dissolution-aiding function according to claim 1, characterized in that: The adapter connecting rod (14) comprises a rod-shaped portion (141) and a connecting portion (142) which are coaxially fixed in sequence from top to bottom, the connecting portion (142) is connected to the central tube (1), and the dissolution-aiding channel (16) is arranged on the connecting portion (142).

3. The soluble bridge plug with dissolution-promoting function according to claim 2, characterized in that: The outer diameter of the connecting portion (142) is greater than the outer diameter of the rod-shaped portion (141).

4. The soluble bridge plug with dissolution-promoting function according to any one of claims 1 to 3, characterized in that: The inner wall of the connecting portion (142) contacts the outer wall of the central tube (1).

5. The soluble bridge plug with dissolution-promoting function according to claim 4, characterized in that: The connecting portion (142) comprises a connecting section (143) and a transition section (144), wherein the transition section (144) is located between the rod-shaped portion (141) and the connecting section (143), the transition section (144) is located above the central tube (1), and the dissolution-aiding channel (16) is arranged on the transition section (144).

6. The soluble bridge plug with dissolution-aiding function according to claim 5, characterized in that: A plurality of dissolution-assisting channels (16) are evenly arranged on the transition section (144) along the circumferential direction, and the central axis of the dissolution-assisting channels (16) and the central axis of the adapter connecting rod (14) are inclined to each other.

7. The soluble bridge plug with dissolution-aiding function according to any one of claims 1 to 3, characterized in that: The outer wall of the connecting portion (142) contacts the inner wall of the central tube (1).

8. The soluble bridge plug with dissolution-aiding function according to claim 7, characterized in that: The connecting portion (142) comprises a connecting section (143) and a transition section (144), wherein the transition section (144) is located between the rod-shaped portion (141) and the connecting section (143), the transition section (144) is located above the central tube (1), and the dissolution-aiding channel (16) is arranged on the transition section (144) and the connecting section (143).

9. The soluble bridge plug with dissolution-promoting function according to claim 8, characterized in that: The dissolution-aiding channel (16) includes a first channel (161) and a second channel (162), wherein the first channel (161) is located in the transition section (144), and the first channel (161) is perpendicular to the central axis of the adapter connecting rod (14), and the second channel (162) is coaxially arranged in the connecting section (143), and the second channel (162) is connected to the first channel (161).

10. A method for removing a bridge plug, characterized in that: When a soluble bridge plug with a dissolution-aiding function according to any one of claims 1 to 9 encounters obstruction or jam during insertion into a well, a dissolution-aiding agent is pumped into the well, so that the dissolution-aiding agent enters the inner cavity of the central pipe (1) through the dissolution-aiding channel (16), dissolving the soluble bridge plug and completing the unblocking.

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