Soluble ball assembly for soluble bridge plug, soluble bridge plug and operation method

Abstract

The invention discloses a soluble ball assembly for a soluble bridge plug, the soluble bridge plug and an operation method, the soluble ball assembly is arranged in the soluble bridge plug, and a first supporting frame and a soluble ball are arranged in an inner cavity of a soluble ball holder; an opening is formed in at least one side surface of the soluble ball retainer; one end of the soluble ball retainer is connected with the motor assembly; the motor assembly comprises a motor, and an output shaft of the motor is connected with one end of the first supporting frame through a sliding ejector rod. The other end of the first supporting frame can abut against the soluble ball, and the soluble ball is limited in the soluble ball holder. The motor is used for controlling the first supporting frame to move towards or away from the soluble ball so that the soluble ball can be jacked or loosened by the first supporting frame, and when the soluble ball is loosened, the soluble ball can be separated from the soluble ball holder from the opening. According to the invention, the fracturing ball does not need to be pumped and thrown after setting, so that the fracturing fluid is saved, the cost is saved, the operation is convenient, and the ball throwing time can be effectively saved.

Description

Technical Field

[0001] The invention relates to the field of reservoir transformation equipment and tools, in particular to a soluble ball component for a soluble bridge plug, the soluble bridge plug and an operation method. Background Art

[0002] As the development of low-permeability and unconventional resources increases year by year, the number of new horizontal wells is increasing. The bridge-shooting combined main transformation technology and tools represented by soluble bridge plugs are playing an increasingly important role in the transformation of new horizontal wells and have become a new "weapon" for this transformation technology. Soluble bridge plugs are a tool used for staged fracturing construction in gas wells. They can effectively seal gas, water, leakage and other layers in the short term, have good pressure-bearing performance, and can degrade on their own in the wellbore after the measures are taken to achieve full-diameter wellbore.

[0003] Generally speaking, soluble bridge plugs are primarily used in the development of shale gas and tight oil and gas wells. Currently, soluble bridge plugs are typically set and fracturing performed using a first-set, then-ball-drop method. Specifically, the soluble fracturing ball in the soluble bridge plug serves as the final sealing component. Typically, after the bridge plug's slips and other setting components are lowered into the well and set, the fracturing ball is separately pumped down and deployed into the fracturing channel, integrating with the bridge plug's setting components to achieve fracturing. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a soluble ball assembly, a soluble bridge plug and an operation method for a soluble bridge plug, so as to avoid the need to separately place the soluble fracturing ball by pumping in the prior art, thereby solving the problem of long placement time and the need for additional fracturing fluid caused by this method.

[0005] To solve the above technical problems, the technical solutions of the present invention are as follows: In a first aspect, an embodiment of the present application provides a soluble ball assembly for a soluble bridge plug, which is arranged inside the soluble bridge plug and includes: a soluble ball, a soluble ball retainer, a motor assembly, a sliding push rod, and a first support frame;

[0006] The inner cavity of the soluble ball retainer is provided with the first support frame and the soluble ball;

[0007] At least one side of the soluble ball retainer is provided with an opening;

[0008] One end of the soluble ball retainer is connected to the motor assembly;

[0009] The motor assembly includes a motor, and the output shaft of the motor is connected to one end of the first support frame through the sliding push rod;

[0010] The other end of the first support frame can abut against the soluble ball and confine the soluble ball in the soluble ball retaining frame;

[0011] The motor is used to control the first support frame to move toward or away from the soluble ball, so as to achieve the tightening or loosening of the soluble ball by the first support frame, wherein the soluble ball can be detached from the soluble ball retaining frame from the opening when the soluble ball is loosened.

[0012] In one or some optional implementations of the embodiment of the present application, a second support frame is further included;

[0013] The second support frame is arranged in the soluble ball retaining frame and is located on a side opposite to the first support frame;

[0014] The second supporting frame can abut against the soluble ball.

[0015] In one or some optional implementations of the embodiment of the present application, the soluble ball is a conductive soluble alloy, and the sliding mandrel and the first support frame are both conductive;

[0016] The soluble ball assembly also includes a voltage sensor;

[0017] The voltage sensor is fixed in the sliding push rod or in the first support frame, and the voltage sensor can sense the soluble ball.

[0018] In one or some optional implementations of the embodiment of the present application, the motor assembly further includes a motor protection case;

[0019] The motor protection shell is sleeved outside the motor.

[0020] In a second aspect, an embodiment of the present application provides a soluble bridge plug, comprising at least one soluble setting anchor mechanism, an adapter, a first connecting rod, a second connecting rod, and the soluble ball assembly described in the first aspect;

[0021] The first connecting rod, the motor, the soluble ball retainer and the second connecting rod are coaxially connected;

[0022] The adapter is a sleeve structure, one end of the adapter is slidably sleeved on the outside of the first connecting rod, wherein the inner diameter of the one end of the adapter is smaller than the outer diameter of the motor or the outer diameter of the soluble ball retainer or the outer diameter of the second connecting rod;

[0023] The at least one soluble setting anchoring mechanism is axially arranged on the second connecting rod.

[0024] In one or some optional implementations of the embodiment of the present application, a limiting seat connected to the other end of the second connecting rod is further included;

[0025] The at least one soluble setting anchoring mechanism includes at least two abutting soluble setting anchoring mechanisms, wherein the soluble setting anchoring mechanism at the head end abuts against the adapter, and the soluble setting anchoring mechanism at the tail end abuts against the limit seat.

[0026] In one or some optional implementations of the embodiment of the present application, each of the soluble setting anchoring mechanisms includes a bridge plug body, a sealing ring, and slips arranged in sequence;

[0027] The bridge plug body is sleeved on the outer side of the second connecting rod, and at least a portion of the bridge plug body is conical in shape;

[0028] The sealing ring is an elastic ring structure; the sealing ring and the slips are sleeved on the conical part, and the sealing ring abuts against the slips.

[0029] In one or some optional implementations of the embodiment of the present application, a plurality of anchoring columns are fixedly connected to the outer side of the slip along its circumference, and the anchoring columns protrude from the slip.

[0030] In one or some optional implementations of the embodiment of the present application, the surface of the anchoring column is inclined toward the adapter.

[0031] In one or some optional implementations of the embodiment of the present application, a plurality of sealing grooves are provided on the outer side of the sealing ring at intervals along the circumference thereof;

[0032] The cross-sectional shape of the sealing groove is a parallelogram, wherein the sealing groove is inclined toward the limiting seat.

[0033] In one or some optional implementations of the embodiment of the present application, a plurality of anti-wear columns are fixedly connected to the outer side of the limit seat along its circumference, and the anti-wear columns are higher than or flush with the maximum outer diameter of the bridge plug body.

[0034] In one or some optional implementations of the embodiment of the present application, the anchor column and the anti-wear column are made of soluble alloys or ceramics.

[0035] In one or some optional implementations of the embodiment of the present application, the soluble setting anchoring mechanism further includes a liner;

[0036] The bridge plug body is connected to the second connecting rod through the liner;

[0037] The lining and the bridge plug body are clearance-fitted;

[0038] The liner and the second connecting rod are interference fit.

[0039] In one or some optional implementations of the embodiment of the present application, the bridge plug body, the sealing ring, the slips and the liner are all made of a soluble material.

[0040] In a third aspect, an embodiment of the present application provides an operation method of a soluble bridge plug, using the soluble bridge plug described in the second aspect, comprising the following steps:

[0041] The soluble bridge plug is lowered into a preset position in the casing and ignited to generate a driving force, which drives the first connecting rod to cause the soluble setting and anchoring mechanism to expand radially for setting and anchoring;

[0042] Performing a perforating operation, after completing the perforating operation, starting the motor to rotate, so that the first support frame moves away from the soluble ball, until the soluble ball is loosened and separated from the soluble ball retaining frame;

[0043] pumping liquid into the casing to make the soluble ball seal the central hole of the soluble setting anchor mechanism;

[0044] Performing pressure testing, if the soluble setting anchor mechanism is successfully released, removing the first connecting rod, the motor, the adapter, the soluble ball retainer, and the second connecting rod from the casing;

[0045] Liquid is pumped into the casing to perform fracturing transformation.

[0046] The beneficial effects of the above technical solutions provided by the embodiments of the present application include at least:

[0047] The soluble ball assembly for a soluble bridge plug provided in an embodiment of the present application is disposed within the soluble bridge plug. A motor controls the movement of a first support frame to control the tightening or loosening of the soluble ball by the first support frame. When the soluble ball is loose, it can be released from the soluble ball retainer to achieve release of the soluble ball. This avoids the prior art process of pumping and deploying fracturing balls after setting the plug. This eliminates the need for additional fracturing fluid for pumping the fracturing balls, conserving fracturing fluid and reducing costs. Furthermore, the operation is convenient and can effectively shorten ball deployment time. Furthermore, controlling the motor to tighten or loosen the soluble ball by the first support frame offers the advantages of high control precision and strong reliability.

[0048] Other features and advantages of the present application will be described in the following description, and in part will become apparent from the description, or will be understood by practicing the present invention. The purposes and other advantages of the present application can be realized and obtained by the structures particularly pointed out in the written description, claims, and drawings.

[0049] The technical solution of the present application is further described in detail below through the accompanying drawings and examples. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] The accompanying drawings are used to provide a further understanding of the present application and constitute a part of the specification. Together with the embodiments of the present application, they are used to explain the present application and do not constitute a limitation of the present application. In the accompanying drawings:

[0051] Figure 1 A three-dimensional diagram of a soluble bridge plug provided in an embodiment of the present application;

[0052] Figure 2 A cross-sectional view of a soluble bridge plug provided in an embodiment of the present application;

[0053] Figure 3 A three-dimensional diagram of a partially soluble bridge plug after the soluble ball is released according to an embodiment of the present application;

[0054] Figure 4 A flow chart of a method for operating a soluble bridge plug provided in an embodiment of the present application;

[0055] Description of reference numerals:

[0056] 1. Adapter; 2. First connecting rod; 3. Motor protection shell; 4. Motor; 5. Sealing cover; 6. Sliding push rod; 7. First support frame; 8. Soluble ball; 9. Second support frame; 10. First bridge plug body; 11. Soluble ball retaining frame; 12. Second connecting rod; 13. First lining; 14. First sealing ring; 15. First slip; 16. Anchor column; 17. Second bridge plug body; 18. Second lining; 19. Second sealing ring; 20. Second slip; 21. Limit seat. DETAILED DESCRIPTION

[0057] In the following description, specific details such as specific system structures and techniques are provided for purposes of illustration rather than limitation to facilitate a thorough understanding of the embodiments of the present application. However, it will be apparent to those skilled in the art that the present application may be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to avoid obscuring the description of the present application with unnecessary detail.

[0058] It should be understood that when used in the present specification and the appended claims, the term "comprising" indicates the presence of described features, integers, steps, operations, elements and / or components, but does not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or collections thereof.

[0059] It will also be understood that the term "and / or" used in this specification and the appended claims refers to and includes any and all possible combinations of one or more of the associated listed items.

[0060] As used in this specification and the appended claims, the term "if" can be interpreted as "when" or "upon" or "in response to determining" or "in response to detecting," depending on the context. Similarly, the phrase "if it is determined" or "if [described condition or event] is detected" can be interpreted as meaning "upon determination" or "in response to determining" or "upon detection of [described condition or event]" or "in response to detecting [described condition or event]," depending on the context.

[0061] In addition, in the description of the present application specification and the appended claims, the terms "first", "second", "third", etc. are only used to distinguish the descriptions and cannot be understood as indicating or implying relative importance.

[0062] References to "one embodiment" or "some embodiments" in this specification mean that a particular feature, structure, or characteristic described in conjunction with that embodiment is included in one or more embodiments of the present application. Thus, phrases such as "in one embodiment," "in some embodiments," "in other embodiments," and "in other embodiments" appearing in various places in this specification do not necessarily refer to the same embodiment, but rather mean "one or more but not all embodiments," unless otherwise specifically emphasized. The terms "including," "comprising," "having," and variations thereof all mean "including but not limited to," unless otherwise specifically emphasized.

[0063] It should be understood that the size of the serial numbers of the steps in the following embodiments does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0064] In order to illustrate the technical solution of the present application, specific embodiments are provided below.

[0065] The inventors discovered that in the prior art, after the soluble bridge plug is used to complete the sealing, the soluble fracturing balls need to be lowered into the well by pumping separately to achieve the sealing purpose. However, this process of pumping the fracturing balls after setting the seal is complicated to operate during construction and takes a long time. In addition, fracturing fluid needs to be used as a transport fluid when pumping the fracturing balls, which increases the amount of fracturing fluid used.

[0066] Based on this, the inventor provides a soluble ball assembly for a soluble bridge plug, a soluble bridge plug and an operation method to solve the above problems.

[0067] Example 1

[0068] See Figure 1-Figure 3The present invention provides a soluble ball assembly for a soluble bridge plug, which is arranged inside the soluble bridge plug. The soluble ball assembly includes: a soluble ball 8, a soluble ball retainer 11, a motor assembly, a sliding push rod 6 and a first support frame 7. The inner cavity of the soluble ball retainer 11 is provided with a first support frame 7 and a soluble ball 8, and at least one side of the soluble ball retainer 11 is provided with an opening (not shown in the figure). The size of the opening should be larger than the size of the soluble ball 8 so that the soluble ball 8 can pass through the opening. One end of the soluble ball retainer 11 is connected to the motor assembly, thereby fixing the soluble ball retainer 11. The motor assembly includes a motor 4, and the output shaft of the motor 4 (not shown in the figure) is connected to one end of the sliding push rod 6. The sliding push rod 6 converts the rotary motion of the motor into axial linear motion. The sliding push rod 6 can refer to the screw in the prior art and is not described in detail here. The other end of the sliding push rod 6 is connected to one end of the first support frame 7. The other end of the first support frame 7 can abut against the soluble ball 8 and limit the soluble ball 8 in the soluble ball retaining frame 11. The motor 4 is used to control the first support frame 7 to move toward or away from the soluble ball 8 to achieve the tightening or loosening of the soluble ball 8 by the first support frame 7. When the soluble ball 8 is loose, it can detach from the soluble ball retaining frame 11 from the opening.

[0069] Further, see Figure 2 or Figure 3 The shape of the area of ​​the soluble ball retainer 11 that accommodates the soluble ball 8 is preferably Figure 2 or Figure 3 The cylindrical shape in the figure has openings on both sides. It is worth noting that the specific shape of the soluble ball retainer 11 is not limited here, as long as it meets the conditions of having an inner cavity and having an opening on at least one side (for the soluble ball 8 to pass through). The shape of the other end of the first support frame 7 is preferably hemispherical, and its curvature is consistent with the curvature of the soluble ball 8. This allows the other end of the first support frame 7 to form a surface contact with the soluble ball 8, thereby maximizing the contact area between the first support frame 7 and the soluble ball 8, thereby achieving the best tightening effect of the first support frame 7 on the soluble ball 8 and preventing the soluble ball 8 from loosening.

[0070] When using, refer to Figure 2 The soluble ball assembly in this embodiment can be set inside the soluble bridge plug and lowered into the well along with the soluble bridge plug. When the soluble anchoring mechanism is not set, the first support frame 7 abuts against the soluble ball 8 to tighten the soluble ball 8. After the soluble bridge plug is set, the ground control system controls the motor 4 to rotate, driving the sliding push rod 6 to move, thereby driving the first support frame 7 to move away from the soluble ball 8 ( Figure 2) to loosen the first support frame 7 from the soluble ball 8 until the soluble ball 8 detaches from the opening of the soluble ball retainer 11, completing the release of the soluble ball 8. This avoids the prior art process of pumping and deploying the fracturing balls after setting the seal. This eliminates the need for increasing the amount of fracturing fluid required for pumping the fracturing balls, conserving fracturing fluid and reducing costs. Furthermore, the system is easy to operate and effectively reduces ball deployment time. Furthermore, the tightening or loosening of the soluble ball 8 by the first support frame 7 is achieved by controlling the motor 4, offering the advantages of high control precision and strong reliability.

[0071] In one embodiment, see Figure 2 and Figure 3 A second support frame 9 is also provided in the soluble ball retaining frame 11. The second support frame 9 is located on the side opposite to the first support frame 7. The second support frame 9 is threadedly connected to the soluble ball retaining frame 11. The second support frame 9 can abut against the soluble ball 8 to provide a limiting support for the soluble ball 8, preventing the soluble ball 8 from loosening when in a tightened state, ensuring reliability while reducing the redundancy of the mechanism.

[0072] In a specific embodiment, the soluble ball 8 is a soluble alloy with electrical conductivity (such as a soluble magnesium alloy) that can dissolve in water. The sliding push rod 6 and the first support frame 7 are both electrically conductive, and a voltage sensor is fixed inside the sliding push rod 6 or the first support frame 7. Since the soluble ball 8 is electrically conductive, the voltage sensor can sense the soluble ball 8. When the motor 4 rotates and drives the sliding push rod 6 and the first support frame 7 to move, the distance between the sliding push rod 6 or the first support frame 7 and the soluble ball 8 changes, so that the voltage value of the voltage sensor changes accordingly. The change in voltage value can effectively determine whether the soluble ball 8 is in a tight or loose state. Specifically, when the soluble ball 8 is in a tight state, the voltage value is the largest, and when the soluble ball 8 is in a tight state, the voltage value is the smallest, so that it is possible to quickly verify or determine whether the soluble ball 8 is successfully released, laying the foundation for the subsequent judgment of the sealing situation.

[0073] In one embodiment, see Figure 2 The motor assembly further includes a motor protection shell 3 sleeved over the motor 4, which provides support and protection for the motor 4. In this embodiment, one end of the soluble ball retainer 11 can also be connected to the motor protection shell 3 to fix the soluble ball retainer 11.

[0074] See Figure 1-Figure 3The soluble bridge plug proposed in the present invention includes an adapter 1, a first connecting rod 2, a second connecting rod 12, at least one soluble sealing anchoring mechanism axially arranged on the second connecting rod 12, and the above-mentioned soluble ball assembly. Specifically, the first connecting rod 2 is coaxially connected to the motor 4, the soluble ball retainer 11, and the second connecting rod 12 in sequence. Here, the connection method can be threaded connection and anti-loosening treatment. The threaded connection method is convenient for installation and disassembly. Compared with the integrated pipe column, the threaded connection method is convenient for maintenance. At the same time, it can also be easily adapted to casings of different depths and inner diameters. The first connecting rod 2 is provided with an inner hole for the power supply and control cable of the motor 4 to pass through. The adapter 1 is a sleeve structure, and one end of the adapter 1 is slidably sleeved on the outside of the first connecting rod 2. The inner diameter of one end of the adapter 1 is smaller than the outer diameter of the motor 4, the outer diameter of the soluble ball retainer 11, or the outer diameter of the second connecting rod 12.

[0075] During the setting process, the first connecting rod 2 pulls the second connecting rod 12 to move axially ( Figure 2 The soluble anchoring mechanism expands radially until it seals against the inner wall of the casing (not shown), achieving the desired setting and anchoring function. After setting, the motor 4 is controlled to rotate, releasing the soluble balls 8, which then seal the central hole of the soluble anchoring mechanism. This completes the sealing of the entire casing, saving ball injection time and reducing the amount of fracturing fluid required to pump the soluble balls 8. Before performing the fracturing transformation, the first connecting rod 2 is moved toward the wellhead by lifting the control cable, and the motor 4, the soluble ball retainer 11 and the second connecting rod 12 are lifted together with the first connecting rod 2. At the same time, since the inner diameter of one end of the adapter 1 is smaller than the outer diameter of the motor 4 or the outer diameter of the soluble ball retainer 11 or the outer diameter of the second connecting rod 12, the adapter 1 is also lifted. Finally, the first connecting rod 2, the motor 4, the soluble ball retainer 11, the second connecting rod 12 and the adapter 1 are all removed from the casing, leaving only the soluble ball 8 and the soluble sealing anchoring mechanism in the casing. After self-dissolution, the casing is emptied without affecting the subsequent fracturing operation.

[0076] In one embodiment, see Figure 2 A sealing cap 5 can be mounted on the outside of the soluble ball retainer 11. The outer side of the sealing cap 5 forms a clearance fit with the inner wall of the adapter 1 to prevent resistance between the sealing cap 5 and the adapter 1 during the aforementioned lifting and setting of the first connecting rod 2. This could affect the lifting and setting operations. Furthermore, the sealing cap 5 supports the soluble ball retainer 11 and keeps it centered, ensuring that the second connecting rod 12 remains centered, thus preventing interference with the subsequent setting operation of the anchor mechanism.

[0077] In one embodiment, see Figure 2The soluble bridge plug also includes a stopper seat 21 connected to the other end of the second connecting rod 12. This connection can be threaded, facilitating installation, removal, and maintenance. When at least two soluble setting anchors are provided, adjacent soluble setting anchors abut against each other, with the leading soluble setting anchor abutting against the adapter and the trailing soluble setting anchor abutting against the stopper seat.

[0078] Each soluble setting anchor mechanism comprises a bridge plug body, a sealing ring, and slips, arranged in sequence. Each bridge plug body is sleeved onto the outside of the second connecting rod 12. At least a portion of the bridge plug body is conical, with the diameter of the cone gradually decreasing toward the sealing ring. The sealing ring is a resilient annular structure. The sealing ring and slips are sleeved onto the conical portion, with the sealing ring abutting the slips.

[0079] For details, see Figure 1 and Figure 2 Two embodiments of soluble setting anchor mechanisms are provided for illustration. A first bridge plug body 10 and a second bridge plug body 17 are both sleeved onto the outside of a second connecting rod 12. One end of the first bridge plug body 10 abuts the adapter 1. A first sealing ring 14 and a first slip 15 are sleeved onto the outside of the other end of the first bridge plug body 10, abutting each other. The other end of the first slip 15 abuts one end of the second bridge plug body 17. Similarly, a second sealing ring 19 and a second slip 20 are sleeved onto the outside of the other end of the second bridge plug body 17, abutting each other. The other end of the second slip 20 abuts a stopper 21.

[0080] During the setting process, the first connecting rod 2 pulls the second connecting rod 12 axially to the left. During this process, since one end of the first bridge plug body 10 abuts against the adapter 1, the adapter 1 provides a rigid mechanical limit, which can limit the axial displacement of the first bridge plug body 10, and the first bridge plug body 10 remains stationary. At the same time, since the second slips 20 abut against the limit seat 21, when the limit seat 21 moves axially to the left along the second connecting rod 12, the second bridge plug body 17, the second sealing ring 19, and the second slips 20 all move axially to the left, and the three remain relatively stationary. Since the second bridge plug body 17 abuts against the first slips 15, when the second bridge plug body 17 moves axially to the left, it pushes the first sealing ring 14 and the first slips 15 to move left along the outer side of the first bridge plug body 10, causing the first sealing ring 14 to expand radially until the outer diameter of the first sealing ring 14 is consistent with the inner diameter of the casing, achieving primary sealing. At this time, the first slips 15 are in sealing abutment with the casing, achieving primary anchoring. After primary sealing and anchoring are complete, the first sealing ring 14 and first slips 15 remain stationary, keeping the second bridge plug body 17 stationary. This forces the second sealing ring 19 and second slips 20 to move leftward along the outside of the second bridge plug body 17, causing the second sealing ring 19 to expand radially until the outer diameter of the second sealing ring 19 matches the inner diameter of the casing, achieving secondary sealing. At this point, the second slips 20 seal and abut against the casing, achieving secondary anchoring. This embodiment enables step-by-step sealing and multi-stage anchoring, effectively improving the sealing and pressure-bearing performance of the soluble bridge plug.

[0081] In a specific embodiment, the bridge plug body, sealing ring and slips are all made of soluble materials, such as soluble magnesium alloy, which can dissolve in water. After the fracturing construction is completed, they can dissolve by themselves without drilling and grinding, saving operation time and labor costs, while also achieving the purpose of environmental protection, and can realize the full diameter of the casing, which can be put into production directly.

[0082] In one embodiment, see Figure 1 and Figure 2 , a plurality of anchoring columns 16 are fixedly connected to the outer side of the slip along its circumference, and the anchoring columns 16 protrude from the slip, so that the outer surface of the anchoring columns 16 forms a tooth-like structure as a whole. Specifically, a plurality of anchoring holes (not shown in the figure) can be set along the circumference of the outer side of the slip, and the anchoring columns 16 are bonded to the anchoring holes. Here, high-strength anaerobic adhesive can be used for bonding, so as to firmly fix the anchoring columns 16. When the slip is in sealing contact with the casing, the anchoring columns 16 can "bite" the inner wall of the casing to prevent the slip from falling off, thereby improving the reliability of the setting and anchoring of the soluble bridge plug. Here, the material of the anchoring column 16 is a soluble alloy or ceramic, preferably ceramic, which has extremely high heat resistance and can maintain high strength and toughness at high temperatures to ensure the setting effect of the slip.

[0083] In one embodiment, see Figure 1 and Figure 2 The surface of the anchor column 16 is inclined toward the adapter 1 and is designed to be in a coupled stress state, which converts the positive load received into radial and axial force components, reduces the axial force received, and thus improves the reliability of the setting.

[0084] In one embodiment, see Figure 1 The outer side of the sealing ring is provided with a plurality of sealing grooves (not shown in the figure) at intervals along its circumference, and the sealing ring is sealed with the sleeve through the sealing grooves. Figure 2 , adopting the pre-action principle, the cross-sectional shape of the sealing groove is a parallelogram, wherein the sealing groove is inclined toward the limit seat 21, that is, the inclination direction is opposite to the pressure action direction during the pressure construction after the setting is completed. When the pressure construction is carried out, under the action of pressure, the cross-sectional shape of the sealing groove changes from a parallelogram to a rectangle, eliminating the deformation effect of pressure on the entire sealing ring, and effectively avoiding the problem of sealing failure of the sealing groove caused by pressure.

[0085] In one embodiment, see Figure 2 The soluble setting anchoring mechanism also includes a liner, and the bridge plug body is connected to the second connecting rod 12 through the liner. The liner and the bridge plug body are clearance-fitted, and the liner and the second connecting rod 12 are interference-fitted. Figure 2 In two embodiments of a soluble setting and anchoring mechanism, a first liner 13 and a second liner 18 are respectively disposed between the first and second bridge plug bodies 10, 17 and the second connecting rod 12. Before the soluble bridge plug is set, these liners provide self-centering support for the first and second bridge plug bodies 10, 17, preventing them from rocking and affecting the setting and anchoring effect. After setting, the first and second liners 13, 18 are lifted to the surface along with the second connecting rod 12, thereby increasing the inner diameters of the first and second bridge plug bodies 10, 17. This effectively reduces their dimensions while maintaining their inner diameters, reducing manufacturing costs and facilitating rapid dissolution.

[0086] At the same time, the inner lining is made of a soluble material, such as a soluble magnesium alloy. If the inner lining accidentally falls off during the process of being lifted to the ground with the second bridge plug body 17, it can quickly dissolve by itself to avoid underground accidents.

[0087] In one embodiment, see Figure 1 and Figure 2 Adapter 1 is a special supporting tool for soluble bridge plug. The outer diameter of adapter 1 is larger than the maximum outer diameter of the bridge plug body and is made of high-strength alloy material. When the soluble bridge plug is pumped into the well, adapter 1 provides wear protection for the bridge plug body.

[0088] In one specific embodiment, multiple anti-wear columns are fixedly connected to the outer side of the stopper seat 21 along its circumference. The anti-wear columns are higher than or flush with the maximum outer diameter of the bridge plug body. During the process of pumping the soluble bridge plug downhole, the wear between the bridge plug body and the inner wall of the casing is effectively reduced, preventing damage to the bridge plug body and subsequent sealing and setting failure. The anti-wear columns are made of a soluble alloy or ceramic. Ceramic is preferred, as it has extremely high heat resistance and can maintain high strength and toughness at high temperatures. Ceramic anti-wear columns provide better wear resistance during the pumping of soluble bridge plugs under high temperature conditions downhole.

[0089] In one embodiment, see Figure 1 In order to further enhance the anti-wear performance and avoid accidental damage to the bridge plug body, the outer surface of the limit seat 21 is provided with an anti-wear coating (not shown in the figure). Here, the anti-wear coating can be formed by anti-wear spraying materials in the existing technology (such as anti-wear corundum).

[0090] Example 2

[0091] Based on the same inventive concept, see Figure 4 The present invention provides a method for operating a soluble bridge plug, using a soluble bridge plug according to an embodiment of the present invention, comprising the following steps:

[0092] Step S1: lower the soluble bridge plug into a preset position of the casing, ignite it to generate a driving force, drive the first connecting rod to drive the soluble setting and anchoring mechanism to expand radially for setting and anchoring.

[0093] Step S1 specifically includes the following steps: Before lowering the soluble bridge plug into the casing, inspect the various components contained in the soluble bridge plug, complete the installation and connection of the various components, the motor's power supply, and the control cable, and connect the control cable to the ground control system. Referring to Example 1, an inner hole is provided in the first connecting rod for the passage of the motor's power supply and control cable. After completing the above preparations, the soluble bridge plug is lowered into the preset position of the casing using the control cable. A uniform lowering method is used in the vertical well section, and a clean water pumping method is used in the horizontal section. Ignition is then performed to provide driving force for the first connecting rod, and the tension change of the control cable is observed. Under the driving force, the first connecting rod moves axially, driving the soluble seal anchoring mechanism to expand radially until it is in sealing contact with the inner wall of the casing, thereby achieving seal anchoring. The working principle and specific process are described in Example 2 and will not be repeated here.

[0094] Step S2: Perform perforation operation. After the perforation operation is completed, start the motor to rotate and move the first support frame away from the soluble ball until the soluble ball is loosened and separated from the soluble ball retaining frame.

[0095] In step S2, after the soluble anchoring mechanism is set, the soluble ball is not released immediately, but the perforation operation is performed first. Here, the perforation operation process in conventional technology can be referred to. Figure 3 , and release the soluble balls after the perforation operation is completed, avoiding the situation where the impact effect of perforation caused by the release of the soluble balls first causes abnormal loosening after setting.

[0096] Step S3: pumping liquid into the casing to make the soluble ball seal the central hole of the soluble setting anchor mechanism.

[0097] Step S4: perform pressure testing. If the soluble setting anchor mechanism is successfully released, remove the first connecting rod, the motor, the adapter, the soluble ball retainer, and the second connecting rod from the casing.

[0098] Step S5: pumping liquid into the casing to perform fracturing.

[0099] Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if such changes and modifications fall within the scope of the claims and their equivalents, the present invention is intended to include such changes and modifications.

Claims

1. A soluble ball assembly for a soluble bridge plug, arranged inside the soluble bridge plug, characterized in that: include: A soluble ball, a soluble ball retainer, a motor assembly, a sliding ejector rod, and a first support frame; The inner cavity of the soluble ball retainer is provided with the first support frame and the soluble ball; At least one side of the soluble ball retainer is provided with an opening; One end of the soluble ball retainer is connected to the motor assembly; The motor assembly includes a motor, and the output shaft of the motor is connected to one end of the first support frame through the sliding push rod; The other end of the first support frame can abut against the soluble ball and confine the soluble ball in the soluble ball retaining frame; The motor is used to control the first support frame to move toward or away from the soluble ball, so as to achieve the tightening or loosening of the soluble ball by the first support frame, wherein the soluble ball can be detached from the soluble ball retaining frame from the opening when the soluble ball is loosened.

2. The soluble ball assembly for soluble bridge plug according to claim 1, wherein: Also included is a second support frame; The second support frame is arranged in the soluble ball retaining frame and is located on a side opposite to the first support frame; The second supporting frame can abut against the soluble ball.

3. The soluble ball assembly for soluble bridge plug according to claim 1, wherein: The soluble ball is a conductive soluble alloy, and the sliding mandrel and the first support frame are both conductive; The soluble ball assembly also includes a voltage sensor; The voltage sensor is fixed in the sliding push rod or in the first support frame, and the voltage sensor can sense the soluble ball.

4. The soluble ball assembly for a soluble bridge plug according to claim 3, wherein: The motor assembly further includes a motor protection shell; The motor protection shell is sleeved outside the motor.

5. A soluble bridge plug, characterized in that: comprising at least one soluble setting anchor mechanism, an adapter, a first connecting rod, a second connecting rod and the soluble ball assembly according to any one of claims 1 to 4; The first connecting rod, the motor, the soluble ball retainer and the second connecting rod are coaxially connected; The adapter is a sleeve structure, one end of the adapter is slidably sleeved on the outside of the first connecting rod, wherein the inner diameter of the one end of the adapter is smaller than the outer diameter of the motor or the outer diameter of the soluble ball retainer or the outer diameter of the second connecting rod; The at least one soluble setting anchoring mechanism is axially arranged on the second connecting rod.

6. The soluble bridge plug according to claim 5, wherein: It also includes a limit seat connected to the other end of the second connecting rod; The at least one soluble setting anchoring mechanism includes at least two abutting soluble setting anchoring mechanisms, wherein the soluble setting anchoring mechanism at the head end abuts against the adapter, and the soluble setting anchoring mechanism at the tail end abuts against the limit seat.

7. The soluble bridge plug according to claim 6, wherein: Each of the soluble setting anchoring mechanisms comprises a bridge plug body, a sealing ring and slips arranged in sequence; The bridge plug body is sleeved on the outer side of the second connecting rod, and at least a portion of the bridge plug body is conical in shape; The sealing ring is an elastic ring structure; the sealing ring and the slips are sleeved on the conical part, and the sealing ring abuts against the slips.

8. The soluble bridge plug according to claim 7, wherein: A plurality of anchoring columns are fixedly connected to the outer side of the slip along its circumference, and the anchoring columns protrude from the slip.

9. The soluble bridge plug according to claim 8, wherein: A surface of the anchor post is inclined toward the adapter.

10. The soluble bridge plug according to claim 7, wherein: The outer side of the sealing ring is provided with a plurality of sealing grooves spaced apart along its circumference; The cross-sectional shape of the sealing groove is a parallelogram, wherein the sealing groove is inclined toward the limiting seat.

11. The soluble bridge plug according to claim 7, wherein: The outer side of the limiting seat is fixedly connected with a plurality of anti-wear columns along its circumference, and the anti-wear columns are higher than or flush with the maximum outer diameter of the bridge plug body.

12. The soluble bridge plug according to claim 11, wherein: The anchoring column and the anti-wear column are made of soluble alloy or ceramic.

13. The soluble bridge plug according to any one of claims 7 to 12, characterized in that: The soluble setting anchoring mechanism further includes an inner liner; The bridge plug body is connected to the second connecting rod through the liner; The lining and the bridge plug body are clearance-fitted; The liner and the second connecting rod are interference fit.

14. The soluble bridge plug according to claim 13, wherein: The bridge plug body, the sealing ring, the slips and the liner are all made of soluble materials.

15. A method for operating a soluble bridge plug, characterized in that: Using the soluble bridge plug according to any one of claims 5 to 14 comprises the following steps: The soluble bridge plug is lowered into a preset position in the casing and ignited to generate a driving force, which drives the first connecting rod to cause the soluble setting and anchoring mechanism to expand radially for setting and anchoring; Performing a perforating operation, after completing the perforating operation, starting the motor to rotate, so that the first support frame moves away from the soluble ball, until the soluble ball is loosened and separated from the soluble ball retaining frame; pumping liquid into the casing to make the soluble ball seal the central hole of the soluble setting anchor mechanism; Performing pressure testing, if the soluble setting anchor mechanism is successfully released, removing the first connecting rod, the motor, the adapter, the soluble ball retainer, and the second connecting rod from the casing; Liquid is pumped into the casing to perform fracturing transformation.

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