A retrievable ball seat with upper and lower inflatable rings and a method of setting

Abstract

This invention belongs to the field of oil and gas field development technology and discloses a soluble ball seat with upper and lower expansion rings and a setting method. The soluble ball seat includes a core rod, and the core rod is fitted with a conical seat, a slip inner core, a locking ring, and a base from top to bottom. A conical hole is provided on one side of the conical seat, and the soluble ball is placed in the conical hole and abuts against the core rod. An upper expansion ring and a lower expansion ring are fitted on the outer wall of the conical seat. The lower end of the upper expansion ring abuts against the upper end of the lower expansion ring, and the lower end of the lower expansion ring abuts against the upper end of the slip inner core. A sealing element is fitted on the outer surface of the upper expansion ring. One end of the core rod is engaged with the conical seat, and the other end is fixedly connected to the base. The sealing element, the upper expansion ring, and the lower expansion ring expand during the sliding process on the conical seat and are fixed to the inner wall of the casing to form a sealing ring space. After the ball seat is set, the soluble ball blocks the central channel of the conical seat under the action of liquid flow, thereby saving the work of pumping and dropping the ball and improving the efficiency of fracturing operations.

Description

Technical Field

[0001] This invention belongs to the field of oil and gas field development technology, and relates to a soluble ball seat with a ball-carrying upper and lower expansion ring and a setting method. Background Technology

[0002] In the field of oil extraction, fracturing technology is one of the important means to improve the production of oil and gas wells. Fracturing operations inject high-pressure fluids into the formation, causing fractures in the formation rock, thereby increasing the flow channels for oil and gas and improving well production. In this process, fracturing tools, especially fracturing balls, play a crucial role. Traditional fracturing balls are mostly made of drillable ductile iron. While this material has a certain strength and wear resistance, it requires an additional drilling step to remove the ball after fracturing. This is not only time-consuming and labor-intensive but also costly, increasing operational complexity and significantly impacting oil production efficiency. To overcome these shortcomings of traditional fracturing balls, the oil industry began exploring the application of dissolvable fracturing balls. Dissolvable fracturing balls are made of special materials that can self-dissolve under specific conditions (such as temperature, pressure, and fluid composition) after fracturing. This not only eliminates the drilling step, saving time and costs, but also simplifies the operation process and significantly improves oil production efficiency.

[0003] The existing ball-seat segmented fracturing uses a combined perforation and ball-seat setting technology. After the ball seat is set, the cable is pulled up and deployed for perforation. Then, the perforation tool and the setting tool are removed from the well. During fracturing, a soluble ball is deployed from the wellhead to seal the central channel of the ball seat for fracturing of the oil and gas reservoir. However, the following problems exist: 1) Deploying the ball reduces the efficiency of the operation, and the soluble ball wastes fracturing fluid during pumping; 2) The setting of the ball seat cannot be verified. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide a soluble ball seat with upper and lower expansion rings and a setting method. The sealing element, upper expansion ring, and lower expansion ring expand during sliding on the cone seat, sealing and fixing the casing. After the ball seat is set, the soluble ball seals the internal channel of the base under the action of liquid flow. The sealing performance of the ball seat is tested, improving reliability and saving time and materials for pumping balls from the wellhead.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: This invention provides a soluble ball seat with a ball-carrying upper and lower expansion ring, comprising a core rod, wherein the core rod is fitted from top to bottom with a conical seat, a locking inner core, a locking ring, and a base; a conical hole is provided on one side of the conical seat, and a soluble ball is disposed in the conical hole and abuts against the core rod; an upper expansion ring and a lower expansion ring are fitted on the outer wall of the conical seat, the lower end of the upper expansion ring abuts against the upper end of the lower expansion ring, and the lower end of the lower expansion ring abuts against the upper end of the locking inner core; a sealing element is fitted on the outer surface of the upper expansion ring; one end of the core rod is engaged with the conical seat, and the other end is fixedly connected to the base.

[0006] Furthermore, the tapered hole is tapered, with the larger end of the tapered hole facing the core rod.

[0007] Furthermore, the cone seat is composed of a large outer cylinder, a frustum of cones, and a small outer cylinder from top to bottom. The cone seat has a hollow structure inside, consisting of a large conical hole, a large inner hole, a small conical hole, and a small inner hole. The upper and lower expansion rings are cylindrical structures, and the inner conical surfaces of the upper and lower expansion rings abut against the frustum of cones.

[0008] Furthermore, the inner core of the slip is provided with a plurality of first grooves along the circumference, and a large ceramic column is disposed in the first groove for connection with the sleeve; the upper and lower ends of the inner core of the slip are provided with bosses, the upper boss abutting against the lower expansion ring and the lower boss abutting against the base, and the upper and lower bosses are fixedly connected to the inner core of the slip.

[0009] Furthermore, the base is provided with a second groove along the circumference, and the small ceramic column is disposed in the second groove; the base is a cylindrical structure, and the inner surface is provided with a large thread and a small thread. The large thread is fixedly connected to the locking ring, and the small thread is fixedly connected to the core rod. The end of the core rod near the soluble ball is used to connect with the setting tool.

[0010] Furthermore, the outer surface of the small outer cylinder is provided with barbs for fixed connection with the locking ring.

[0011] Furthermore, a third groove is provided on the side of the cone seat near the cone-shaped hole, and the small ceramic column is disposed in the third groove.

[0012] Furthermore, the soluble ball, cone seat, upper expansion ring, lower expansion ring, slip core, locking ring, and base are made of magnesium-based and aluminum-based soluble metal materials, which automatically dissolve after fracturing.

[0013] This invention also provides a method for setting a soluble ball seat with a ball-carrying upper and lower expansion ring, comprising the following steps: In use, the setting tool pulls the upper end of the core rod, the lower end of the core rod is connected to the base, the base and the inner core of the slip move upward, the diameter of the inner core of the slip expands continuously, the bottom of the cone seat is squeezed into the locking ring, the sealing element, the outer wall of the upper expansion ring and the lower expansion ring abut against the inner wall of the casing to complete the seal, the core rod is pulled further, the core rod and the base move relative to each other and separate, the soluble ball moves into the cone seat under the drive of the fracturing fluid, the inner hole channel is blocked, and segmented fracturing is performed, the soluble ball automatically dissolves after the fracturing is completed.

[0014] Furthermore, the relative movement and separation between the core rod and the base includes a mismatch in the hardness of the core rod and the base, whereby the core rod separates from the base first under the action of the setting tool, and then is pulled out along the sleeve inlet direction.

[0015] Compared with the prior art, the present invention has the following beneficial technical effects: This invention discloses a soluble ball seat with upper and lower expansion rings. The cone seat and the inner core of the slip are a cone-shaped combination sealing component. During the movement of the cone seat, the upper and lower expansion rings seal and fix the casing. The soluble ball is placed in the conical hole. After the core rod separates from the base, under the action of the setting tool, the soluble ball blocks the central channel of the cone seat under the action of liquid flow, thereby saving the work of pumping and dropping the ball and improving the efficiency of fracturing operations.

[0016] This invention provides a soluble ball seat with a ball-carrying upper and lower expansion ring, which not only saves the step of putting soluble balls into the wellhead, but also strengthens the stability of the cone seat, slip core and base. After the base reaches the predetermined position and achieves sealing and fixation, the setting and sealing of the base is immediately verified, which improves the reliability of the base construction.

[0017] This invention relates to a soluble ball seat with upper and lower expansion rings. The soluble ball, cone seat, upper expansion ring, lower expansion ring, slip core, locking ring, and base are all made of magnesium-based and aluminum-based soluble metal materials, which automatically dissolve after fracturing. Attached Figure Description

[0018] Figure 1 This is a cross-sectional view of a soluble ball seat with a ball-carrying upper and lower expansion ring according to the present invention. Figure label: 1-Core rod; 2-Soluble ball; 3-Conical seat; 4-Seal; 5-Upper expansion ring; 6-Lower expansion ring; 7-Clip inner core; 8-Large ceramic column; 9-Small ceramic column; 10-Locking ring; 11-Base. Detailed Implementation

[0019] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0020] Example 1 This invention provides a soluble ball seat with a ball-carrying upper and lower expansion ring, such as... Figure 1 As shown, the device includes a core rod 1, which is fitted with a conical seat 3, a locking inner core 7, a locking ring 10, and a base 11 from top to bottom. A conical hole is provided on one side of the conical seat 3, and a soluble ball 2 is disposed in the conical hole and abuts against the core rod 1. An upper expansion ring 5 and a lower expansion ring 6 are fitted on the outer wall of the conical seat 3. The lower end of the upper expansion ring 5 abuts against the upper end of the lower expansion ring 6, and the lower end of the lower expansion ring 6 abuts against the upper end of the locking inner core 7. A sealing element 4 is fitted on the outer surface of the upper expansion ring 5. One end of the core rod 1 is engaged with the conical seat 3, and the other end is fixedly connected to the base 11.

[0021] Specifically, a soluble ball seat with a ball-carrying upper and lower expansion ring includes a core rod 1 and a conical seat 3. The core rod 1 has a cross-shaped structure, with one end passing through the interior of the conical seat 3 in the vertical direction. The side wall of the core rod 1 near the bottom end has external threads for detachable or threaded connection with the base 11. The other end connects to a setting tool. The side of the core rod 1 facing downwards in the horizontal direction has a chamfer that abuts against the upper end face of the conical seat 3. The core rod 1 in the horizontal direction is a horizontal core rod, and the core rod 1 in the vertical direction is a vertical core rod.

[0022] The base 11 has a second groove along its circumference, and the small ceramic column 9 is placed in the second groove to protect the ball seat during delivery; the cone seat 3 has a third groove along its circumference on the side away from the base 11, and the small ceramic column 9 is placed in the third groove to protect the ball seat during delivery.

[0023] like Figure 1 As shown, from left to right, the outer side of the cone seat 3 consists of a large outer cylinder, a truncated cone, and a small outer cylinder. In practical applications, the large outer cylinder faces upwards, the small outer cylinder faces downwards, and the diameter of the truncated cone decreases continuously from top to bottom. The large end of the truncated cone is fixedly connected to the large outer cylinder, and the small end is fixedly connected to the small outer cylinder. It should be noted that the fixed connection here is welded, and the connection is smooth and burr-free, which enables the cone seat 3 to have good sliding or moving performance.

[0024] In addition to being fixedly connected, the large outer cylinder, the frustum of a cone, and the small outer cylinder can also be a single integrated structure.

[0025] A third groove is provided circumferentially on the side of the large outer cylinder away from the truncated cone. The third groove is used to fill the large ceramic column 8. It should be noted that the height of the large ceramic column located in the third groove must be greater than the width of the third groove.

[0026] The cone seat 3 has a hollow structure with a large conical hole, a large inner circular hole, a small conical hole, and a small inner circular hole arranged from top to bottom. The taper of the large conical hole matches the degree of the chamfer in the horizontal direction of the core rod 1. The diameter of the large inner circular hole is the same as the diameter of the small end of the large conical hole. The diameter of the large end of the small conical hole is the same as the diameter of the large inner circular hole. The diameter of the small end of the small conical hole is the same as the diameter of the small inner circular hole. In addition, the diameter of the small inner circular hole matches the diameter of the vertical core rod.

[0027] A conical hole is provided between the large outer cylinder and the large inner hole. The conical hole is conical, with the small end facing outward and the large end facing inward. It is located at one end close to the core rod 1. The soluble ball 2 is installed in the conical hole. When the core rod 1 is detached from the conical seat 3, the soluble ball 2 lacks constraint and rolls along the slope of the conical hole, entering the upper end of the internal channel of the conical seat 3.

[0028] Soluble balls 2 typically serve to block specific channels or separate different layers. During multi-layer fracturing, soluble balls 2 are placed in the appropriate positions to prevent fracturing fluid from flowing to already fractured layers, ensuring that the fracturing fluid can accurately act on the target layer to create and propagate fractures, thereby improving oil extraction efficiency.

[0029] The cone seat 3 provides a suitable placement position for the soluble ball 2. The dissolution of the cone seat 3 can prevent it from remaining downhole for a long time and hindering subsequent production. No drilling or other treatments are required, which simplifies the subsequent downhole maintenance and production process.

[0030] An upper expansion ring 5 and a lower expansion ring 6 are fitted around the outer side of the truncated cone. The upper expansion ring 5 has a cylindrical structure, and its outer diameter remains consistent from top to bottom. A sealing element 4 is embedded in the outer surface of the upper expansion ring 5. In this embodiment, the sealing element 4 is an O-ring. The diameter of the inner surface of the upper expansion ring 5 decreases continuously from top to bottom and abuts against the side wall of the truncated cone. The lower end of the upper expansion ring 5 abuts against the upper end of the lower expansion ring 6.

[0031] The lower expansion ring 6 is generally shaped like an inverted U-shape, with a chamfer at the connection point with the cone seat 3. When the cone seat 3 is connected to the locking ring 10 and locked, the diameters of the upper expansion ring 5 and the lower expansion ring 6 continuously increase. When the upper expansion ring 5 and the lower expansion ring 6 have the same diameter as the sleeve, and under the action of the setting tool, the sealing element 4, the upper expansion ring 5, and the lower expansion ring 6 are tightly attached to the inner wall of the sleeve, completing the seal. The lower end of the lower expansion ring 6 abuts against the upper end of the slip core 7.

[0032] The upper expansion ring 5 and the lower expansion ring 6 are tightly fitted to the casing through expansion to prevent displacement due to high-pressure fluid impact during fracturing, thus ensuring the sealing and safety of the fracturing operation.

[0033] The sleeve is fitted on the outside of the cone seat 3 and the inner core of the slip 7. When the base 11 does not move upward, there is a certain gap between the large outer cylinder and the inner core of the slip and the sleeve, which makes it easy to install the soluble ball seat of the ball-carrying upper and lower expansion rings into the designated position of the sleeve.

[0034] The inner core 7 of the slip is conical. When subjected to axial force, the conical inner core 7 expands or contracts radially, thereby better gripping or loosening the cone seat 3.

[0035] The Kawa inner core 7 can avoid the need for manual disassembly after the fracturing operation is completed.

[0036] It should be noted that the tilt angle of the truncated cone is the same as the tilt angle of the cone-shaped inner core 7, which facilitates advancement. When the setting tool applies axial force, because the sides of the truncated cone are tilted, the axial force can be decomposed into an effective advancing force of the base 11 and a radial expansion force. In scenarios where a tight fit with the sleeve is required, the radial expansion force allows the truncated cone to make better contact with the inner core 7 of the slip.

[0037] Specifically, after the inner core 7 of the slip is advanced to the designated position, the radial expansion force generated by the axial thrust allows the sealing element 4, the upper expansion ring 5, and the lower expansion ring 6 to better fit the sleeve, thereby achieving a better sealing effect. In addition, this disassembly method also allows the inner core 7 of the slip to push aside surrounding obstacles during the advancement process, whereas cylindrical shapes are easily blocked by obstacles.

[0038] The outer surface of the inner core 7 of the slip is provided with a first groove for installing a large ceramic column. The inner core 7 of the slip has bosses at both the upper and lower ends, which are located on the side near the cone seat 3. The boss at the upper end of the inner core 7 abuts against the protruding part of the lower expansion ring 6, which facilitates the connection between the lower expansion ring 6 and the inner core 7 of the slip. The boss at the lower end of the inner core 7 fits against the upper end of the base 11.

[0039] The base 11 is fitted at the bottom of the vertical core rod. The interior of the base 11 is also hollow. The locking ring 10 is fitted inside the base 11. The inner surface of the base 11 is machined with large threads and small threads. The large threads are used to connect with the locking ring 10, and the small threads are used to connect with the vertical core rod.

[0040] The locking ring 10 prevents accidental detachment or loosening between components, ensuring reliable operation of the device. After fracturing is completed, no excess components are left downhole to hinder subsequent production activities, reducing the workload of manual cleaning and handling.

[0041] A second groove is provided circumferentially on the side wall of the base 11 facing the inner core 7 of the card. The small ceramic column is installed in the second groove. The installation of the small ceramic column in the second groove can improve electrical insulation, reduce mechanical friction, enhance structural stability, improve the performance index of the soluble ball seat of the ball-carrying upper and lower expansion ring, extend service life, and improve reliability.

[0042] Among them, the soluble ball 2, cone seat 3, upper expansion ring 5, lower expansion ring 6, slip inner core 7, locking ring 10 and base 11 are made of magnesium-based and aluminum-based soluble metal materials, which automatically dissolve after fracturing.

[0043] The large ceramic column 8 is fixed on the side wall of the inner core 7 of the slip and mainly serves as an anchor. It is embedded in the inner wall of the sleeve to form a stable structure, ensuring that the inner core 7 of the slip and the base 11 can be firmly fixed in the appropriate position. The large ceramic column 8 is designed with a certain angle, which not only helps to better embed in the inner wall of the sleeve, but also provides stronger fixing force, thereby increasing the stability of the entire structure.

[0044] After the base 11 is melted, there is no need to use traditional methods to destroy or remove the base 11, which improves the efficiency and economy of the entire production process.

[0045] In summary, the upper end of the vertical core rod of the soluble ball seat with ball-carrying upper and lower expansion rings is threaded to the setting tool, and the lower end is threaded to the base 11. Before the vertical core rod is connected to the base 11, it first passes through the conical seat 3 and then through the locking ring 10. The locking ring 10 is installed inside the base 11 and is threaded to the base 11. Before the vertical core rod passes through the conical seat 3, the soluble ball 2 is placed in the conical hole, and the side wall of the soluble ball 2 abuts against the conical hole and the side wall of the vertical core rod.

[0046] Example 2 This invention discloses a method for setting a soluble ball seat with a ball-carrying upper and lower expansion ring, comprising the following steps: In use, the setting tool pulls the upper end of the core rod 1, the lower end of the core rod 1 is connected to the base 11, the base 11 and the inner core 7 of the slip move upward, the diameter of the inner core 7 of the slip expands continuously, the bottom of the cone seat 3 is squeezed into the locking ring 10, the outer walls of the sealing element 4, the upper expansion ring 5 and the lower expansion ring 6 abut against the inner wall of the casing to complete the seal, the core rod 1 is pulled further, the core rod 1 and the base 11 move relative to each other and separate, the soluble ball 2 moves into the cone seat 3 under the drive of the fracturing fluid, the inner hole channel is blocked, and segmented fracturing is performed, the soluble ball 2 automatically dissolves after the fracturing is completed.

[0047] The relative movement and separation of the core rod 1 and the base 11 include the mismatch in hardness between the core rod 1 and the base 11, the core rod 1 separating from the base 11 first under the action of the setting tool, and then being pulled out along the sleeve inlet direction.

[0048] Specifically: The setting tool is threaded to the upper end of the core rod 1. Under the action of the external force of the setting tool, the core rod 1 moves upward. Since the lower end of the core rod 1 is threaded to the base 11, the upper end of the base 11 is provided with an upper expansion ring 5, a lower expansion ring 6, and a slip inner core 7. The internal structure of the slip inner core 7 is conical, which abuts against the side wall of the conical seat 3. The slip inner core 7 expands outward continuously until the large ceramic column 8 is embedded in the sleeve. The conical seat 3 penetrates deeper into the slip inner core 7 until the bottom of the conical seat 3 penetrates into the locking ring 10, completing the locking. During this period, the outer diameter of the upper expansion ring 5 and the lower expansion ring 6 expands outward continuously. When the outer diameter of the upper expansion ring 5 and the lower expansion ring 6 expands to the same as the inner diameter of the sleeve, under the action of the setting force provided by the setting tool, the sealing element 4, the upper expansion ring 5, and the lower expansion ring 6 are tightly attached to the inner wall of the sleeve, completing the seal.

[0049] The setting tool continuously provides setting force. When the hardness of the bottom end of the core rod 1 does not match that of the base 11, it breaks. The core rod 1 moves upward along the setting tool. When the lower end of the core rod 1 is pulled out of the casing, fracturing fluid is added. Under the action of the fracturing fluid, the soluble ball 2 rolls into the cone seat 3, sealing the internal channel and completing the sealing, thus forming the sealing effect of segmented fracturing.

[0050] The fracturing process involves injecting fracturing fluid into the wellbore, gradually increasing the bottomhole pressure. When this pressure exceeds the tensile strength of the rock and the fracturing pressure caused by geostress, the rock fractures. These fractures extend perpendicular to the direction of minimum principal stress and continue to expand and extend with the continued injection of fracturing fluid. To keep the fractures open, proppant (such as silica sand or ceramsite) is added to the fracturing fluid. After fracturing is completed, the proppant remains in the fractures to prevent them from closing, thus creating highly conductive channels for oil and gas flow.

[0051] After fracturing, the soluble ball 2, cone seat 3, upper expansion ring 5, lower expansion ring 6, slip core 7, locking ring 10 and base 11 were dissolved.

[0052] In summary, the cone seat 3 and the inner core 7 of the slip are combined, and the sealing element 4, upper expansion ring 5, and lower expansion ring 6 seal and fix the casing during the pushing process of the cone seat 3. The soluble ball 2 is placed in the conical hole. After the core rod 1 is separated from the base 11, under the action of the setting tool, the soluble ball 2 seals the internal channel of the cone seat 3 under the action of the fracturing fluid flow, thereby saving the work of pumping and dropping the ball and improving the efficiency of fracturing operation.

[0053] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", "axial", "radial", "circumferential", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the present 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 limiting the present invention.

[0054] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

Claims

1. A soluble ball seat with a ball-carrying upper and lower expansion ring, characterized in that: The device includes a core rod (1), which is fitted with a cone seat (3), a slip inner core (7), a locking ring (10), and a base (11) from top to bottom. A cone-shaped hole is provided on one side of the cone seat (3), and a soluble ball (2) is placed in the cone-shaped hole and abuts against the core rod (1). An upper expansion ring (5) and a lower expansion ring (6) are fitted on the outer wall of the cone seat (3). The lower end of the upper expansion ring (5) abuts against the upper end of the lower expansion ring (6), and the lower end of the lower expansion ring (6) abuts against the upper end of the slip inner core (7). A sealing element (4) is fitted on the outer surface of the upper expansion ring (5). One end of the core rod (1) is engaged with the cone seat (3), and the other end is fixedly connected to the base (11).

2. The soluble ball seat with ball-carrying upper and lower expansion rings according to claim 1, characterized in that: The tapered hole is tapered, with the larger end of the tapered hole facing the core rod (1).

3. The soluble ball seat with ball-carrying upper and lower expansion rings according to claim 1, characterized in that: The cone seat (3) is composed of a large outer cylinder, a frustum of a cone and a small outer cylinder from top to bottom. The cone seat (3) has a hollow structure inside, consisting of a large conical hole, a large inner hole, a small conical hole and a small inner hole. The upper expansion ring (5) and the lower expansion ring (6) are cylindrical structures, and the inner conical surfaces of the upper expansion ring (5) and the lower expansion ring (6) abut against the frustum of a cone.

4. The soluble ball seat with ball-carrying upper and lower expansion rings according to claim 2, characterized in that: The inner core (7) of the slip is provided with a plurality of first grooves along the circumference, and the large ceramic column (8) is provided in the first groove for connection with the sleeve; the inner core (7) of the slip is provided with bosses at the upper and lower ends, the upper boss abutting against the lower expansion ring (6) and the lower boss abutting against the base (11), and the upper boss and the lower boss are fixedly connected to the inner core (7).

5. The soluble ball seat with ball-carrying upper and lower expansion rings according to claim 1, characterized in that: The base (11) is provided with a second groove along the circumference, and the small ceramic column (9) is disposed in the second groove; The base (11) is a cylindrical structure with large and small threads on its inner surface. The large thread is fixedly connected to the locking ring (10), and the small thread is fixedly connected to the core rod (1). The end of the core rod (1) near the soluble ball (2) is used to connect with the sealing tool.

6. The soluble ball seat with ball-carrying upper and lower expansion rings according to claim 3, characterized in that: The outer surface of the small outer cylinder is provided with barbs for fixed connection with the locking ring (10).

7. The soluble ball seat of the ball-carrying upper and lower expansion rings according to claim 5, characterized in that: The cone seat (3) has a third groove on the side near the cone hole, and the small ceramic column (9) is placed in the third groove.

8. The soluble ball seat with ball-carrying upper and lower expansion rings according to claim 1, characterized in that: The soluble ball (2), cone seat (3), upper expansion ring (5), lower expansion ring (6), slip core (7), locking ring (10) and base (11) are made of magnesium-based and aluminum-based soluble metal materials, which automatically dissolve after fracturing.

9. A method for setting and sealing a soluble ball seat with a ball-carrying upper and lower expansion ring, characterized in that, The soluble ball seat based on the ball-carrying upper and lower expansion rings as described in any one of claims 1-8 Includes the following steps: When in use, the setting tool pulls the upper end of the core rod (1), and the lower end of the core rod (1) is connected to the base (11). The base (11) and the inner core (7) of the slip move upward. The diameter of the inner core (7) of the slip expands continuously. The bottom of the cone seat (3) is squeezed into the lock ring (10). The outer walls of the sealing element (4), the upper expansion ring (5) and the lower expansion ring (6) abut against the inner wall of the casing to complete the seal. Continue to pull the core rod (1). The core rod (1) and the base (11) move relative to each other and separate. The soluble ball (2) moves into the cone seat (3) under the drive of the fracturing fluid, and seals the inner hole channel. Segmented fracturing is carried out. After the fracturing is completed, the soluble ball (2) automatically dissolves.

10. The method for setting and sealing a soluble ball seat with a ball-carrying upper and lower expansion ring according to claim 9, characterized in that: The relative movement and separation of the core rod (1) and the base (11) include the mismatch in hardness between the core rod (1) and the base (11), the core rod (1) being separated from the base (11) first under the action of the setting tool, and then being pulled out along the sleeve inlet direction.

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