Dual stage sealable metal dissolvable bridge plug

Abstract

The application discloses a two-stage sealing type metal soluble bridge plug, which comprises a mandrel (2) and a cone (12) sleeved outside the mandrel (2), the outer surface of the cone (12) is provided with an upper conical surface section (1201) and a lower conical surface section (1202) arranged in sequence, the upper conical surface section (1201) is sleeved with an upper locking block group ring (6) and an upper metal sealing ring (9) arranged in sequence, the lower conical surface section (1202) is sleeved with a lower metal sealing ring (15) and an anchoring block group ring (13) arranged in sequence, the lower end of the mandrel (2) is connected with a releasing joint (14), and the anchoring block group ring (13) is connected with the releasing joint (14) in sequence. The two-stage sealing type metal soluble bridge plug adopts the soluble metal sealing ring, is suitable for working conditions of high temperature, high pressure and high salinity, realizes rapid dissolution of the bridge plug, has less residues, guarantees rapid production of unconventional oil and gas wells, and reduces a construction period and economic cost.

Description

Technical Field

[0001] This invention relates to the field of downhole tools for oil and gas drilling and fracturing, specifically a two-stage sealed metal soluble bridge plug. Background Technology

[0002] To increase oil recovery and improve oilfield production efficiency, stratified injection and production, and multi-stage fracturing are effective methods for developing special oil reservoirs. Typically, during fracturing, bridge plugs are used to seal the downhole casing and isolate the target reservoir segment. Soluble bridge plugs are a new type of stratified fracturing tool for shale gas. After fracturing, the bridge plug body can be completely dissolved by the wellbore temperature and a certain level of salinity in the fluid environment, ensuring full-bore production. This method offers advantages such as low overall cost, short commissioning time, reduced operational risks, and the ability to perform secondary fracturing.

[0003] Over the years, bridge plugs have evolved from cast iron drillable bridge plugs and composite drillable bridge plugs to soluble bridge plugs. Currently, most common soluble bridge plugs achieve casing sealing and interlayer isolation through the elastic deformation of a soluble rubber sleeve under compression. The metal components of soluble bridge plugs can dissolve well under certain downhole temperature and salinity conditions, ultimately forming powdery or fine granular residues. In contrast, soluble rubber sleeves primarily degrade into blocky residues, resulting in slower dissolution rates and longer cycles. Furthermore, as the number of bridge plugs deployed increases, the accumulation of dissolved residues affects flowback production, often requiring drilling and well cleaning operations, increasing costs. Moreover, with the in-depth development of unconventional oil and gas reservoirs, higher requirements are placed on the overall performance indicators, pressure, and temperature ratings of soluble bridge plugs, continuously developing towards high-temperature resistance, high-pressure performance, rapid dissolution, and low residue levels. Soluble rubber, however, has certain shortcomings in terms of high-temperature resistance and sealing stability. Summary of the Invention

[0004] To address the issue of rubber aging in soluble bridge plugs, this invention provides a dual-stage sealing soluble metal bridge plug. This dual-stage sealing soluble metal bridge plug uses a soluble metal sealing ring, making it suitable for high-temperature, high-pressure, and high-mineralization conditions. It achieves rapid dissolution of the bridge plug with minimal residue, ensuring rapid commissioning of unconventional oil and gas wells and reducing construction time and economic costs.

[0005] The technical solution adopted by this invention to solve its technical problem is:

[0006] A dual-stage sealed metal soluble bridge plug includes an inner and outer mandrel and a cone. The outer surface of the cone has an upper conical section and a lower conical section arranged vertically. The top end of the upper conical section faces upward and the bottom end faces downward. An upper locking block ring and an upper metal sealing ring are arranged vertically on the upper conical section. The top end of the lower conical section faces downward and the bottom end faces upward. A lower metal sealing ring and an anchoring block ring are arranged vertically on the lower conical section. The lower end of the mandrel is connected to a release connector. The anchoring block ring is connected vertically to the release connector. When the upper locking block ring moves downward relative to the mandrel, the cone can also move downward relative to the mandrel. The upper locking block ring, the upper metal sealing ring, the lower metal sealing ring, and the anchoring block ring can all expand radially.

[0007] The beneficial effects of this invention are as follows: The dual-stage sealing high-temperature and high-pressure resistant all-metal soluble bridge plug, by employing symmetrically distributed wedge-shaped metal sealing rings and support rings to form a dual-stage sealing structure, can increase the effective sealing area and improve the sealing pressure-bearing reliability and stability of the all-metal soluble bridge plug; combined with the high-temperature and corrosion-resistant coating on the surface of the metal sealing ring, it enhances its adaptability to complex well bottom conditions and the effective sealing pressure-bearing working time, ensuring the smooth construction of fracturing operations; moreover, the overall structure of this all-metal soluble bridge plug is simple and novel; it has technical characteristics such as large diameter, high pressure resistance, strong sealing pressure-bearing stability, fast dissolution, and low residue; it can be quickly dissolved after staged fracturing construction, realizing well opening and production, reducing construction cycle and economic costs. Attached Figure Description

[0008] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0009] Figure 1 This is a schematic diagram of the dual-stage sealed metal soluble bridge plug described in this invention.

[0010] Figure 2 This is a schematic diagram of the setting and anchoring working state of the dual-stage sealed metal soluble bridge plug described in this invention.

[0011] Figure 3 This is a schematic diagram of the mandrel.

[0012] Figure 4 This is a schematic diagram of a cone.

[0013] Figure 5 This is a schematic diagram of the push ring.

[0014] Figure 6 This is a schematic diagram of the upper locking block.

[0015] Figure 7 This is a schematic diagram of the first support ring.

[0016] Figure 8 This is a schematic diagram of the anchor block assembly ring.

[0017] The annotations in the attached figures are explained as follows:

[0018] 1. Push cylinder; 2. Mandrel; 3. Limiting screw; 4. Push ring; 5. Outer clamping ring; 6. Upper locking block assembly ring; 7. Anchoring tooth; 8. Limiting clamping ring; 9. Upper metal sealing ring; 10. First support ring; 11. Second support ring; 12. Cone; 13. Anchoring block assembly ring; 14. Release connector; 15. Lower metal sealing ring; 16. Sleeve; 17. Soluble ball;

[0019] 201. First major diameter segment; 202. Second major diameter segment; 203. First minor diameter segment; 204. Second minor diameter segment; 205. Annular conical outer transition segment;

[0020] 401. Outer small diameter section; 402. Outer large diameter section; 403. Annular groove; 404. Lower guide rib;

[0021] 601. Upper locking block; 602. Upper guide groove;

[0022] 1001, U-shaped groove;

[0023] 1201. Upper conical section; 1202. Lower conical section; 1203. Annular conical seat cover;

[0024] 1301, Anchor block; 1302, Lower guide groove;

[0025] 1401. Upper guide rib. Detailed Implementation

[0026] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0027] A dual-stage sealed metal soluble bridge plug includes an inner and outer mandrel 2 and a cone 12. The outer surface of the cone 12 has an upper conical section 1201 and a lower conical section 1202 arranged vertically. Both the upper conical section 1201 and the lower conical section 1202 are conical surfaces. The top end of the upper conical section 1201 faces upward and the bottom end faces downward (i.e., the outer diameter of the upper end of the upper conical section 1201 is smaller than the outer diameter of the lower end). The upper conical section 1201 is fitted with an upper locking block ring 6 and an upper metal sealing ring 9 arranged vertically. The top end of the lower conical section 1202 faces downward and the bottom end faces downward. Facing upwards (i.e., the lower outer diameter of the lower conical section 1202 is smaller than the upper outer diameter), the lower conical section 1202 is fitted with a lower metal sealing ring 15 and an anchoring block ring 13 arranged vertically. The lower end of the spindle 2 is connected to a release connector 14. The anchoring block ring 13 is vertically connected to the release connector 14. When the upper locking block ring 6 moves downwards relative to the spindle 2, the cone 12 can also move downwards relative to the spindle 2. The upper locking block ring 6, the upper metal sealing ring 9, the lower metal sealing ring 15, and the anchoring block ring 13 can all expand radially. Figures 1 to 8 As shown.

[0028] The dual-stage sealing metal soluble bridge plug also includes a fitting assembly for bridge plug setting: a pusher 1 and a limiting screw 3. The pusher 1 and the pusher ring 4 are connected by the limiting screw 3. The upper metal sealing ring 9 and the lower metal sealing ring 15 are symmetrically installed on the upper and lower ends of the cone 12, forming a combined dual-stage metal sealing structure. The components of the dual-stage sealing metal soluble bridge plug are sequentially axially installed at both ends of the cone 12, cooperating with each other; and are integrally mounted on the mandrel 2, connected to the lower end of the mandrel 2 via the internal thread of the release connector 14, achieving axial positioning and locking.

[0029] In this embodiment, the mandrel 2 is an upright tubular structure. The outer surface of the mandrel 2 contains, from top to bottom, a first large-diameter section 201, a second large-diameter section 202, a first small-diameter section 203, and a second small-diameter section 204. The outer diameters of the first large-diameter section 201, the second large-diameter section 202, the first small-diameter section 203, and the second small-diameter section 204 decrease sequentially. The cone 12 is an upright cylindrical structure. The upper conical section 1201 and the lower conical section 1202 are symmetrical and mirror images of each other. Figure 3 As shown.

[0030] In this embodiment, the axis of the mandrel 2 coincides with the axis of the cone 12. The upper end of the mandrel 2 is located outside the upper end of the cone 12, and the lower end of the mandrel 2 is located outside the lower end of the cone 12. The first large diameter section 201 is provided with an internal thread. The cone 12 is mainly fitted outside the first small diameter section 203. An annular conical outer transition section 205 is provided between the second large diameter section 202 and the first small diameter section 203. An annular conical seat cover 1203 is provided inside the upper end of the cone 12. The annular conical seat cover 1203 is a conical surface. The top end of the annular conical seat cover 1203 faces down and the bottom end faces up. The annular conical outer transition section 205 matches and abuts against the annular conical seat cover 1203. The second small diameter section 204 is fitted inside the release connector 14. The second small diameter section 204 is connected to the release connector 14 with internal and external threads. The external thread of the second small diameter section 204 can cut off the internal thread of the release connector 14.

[0031] The mandrel 2 is made of alloy structural steel and has a stepped through hole inside. The first large diameter section 201 has an internal thread for connection with a standard setting tool. The mandrel 2 is threadedly connected to the release connector 14 to achieve axial positioning and locking; during bridge plug setting, it transmits axial load and shears the internal thread of the release connector 14, achieving bridge plug release setting. The cone 12 has an internal through hole, and the upper end of the cone 12 has an annular conical setting surface 1203. During downhole operation, when the soluble ball 17 is pressed against the surface, it seals the center hole of the bridge plug, establishing a seal. Figures 1 to 4 As shown.

[0032] In this embodiment, the dual-stage sealed metal soluble bridge plug further includes a push ring 4, which is sleeved on the outside of the mandrel 2. The push ring 4 is vertically connected to the upper locking block ring 6. The outer surface of the push ring 4 has an outer small diameter section 401 and an outer large diameter section 402 arranged vertically. The lower part of the outer small diameter section 401 is provided with an annular groove 403. The lower end face of the push ring 4 is a lower conical surface, with the top end of the lower conical surface facing down and the bottom end facing up. The lower end face of the push ring 4 is provided with multiple lower guide ribs 404, which are arranged at intervals along the circumference of the push ring 4 and extend along the diameter direction of the push ring 4. Figure 5 As shown.

[0033] The push ring 4 is circular and made of alloy structural steel or stainless steel. The inner hole of the push ring 4 is clearance-fitted with the spindle 2. The annular groove 403 on the push ring 4 is used to install the limit screw 3 to achieve axial positioning. The lower end of the push ring 4 is provided with several lower guide ribs 404, and the lower guide ribs 404 are designed with a certain inclination angle. The number and inclination angle of the lower guide ribs 404 are the same as the number and inclination angle of the upper locking blocks 601.

[0034] In this embodiment, the upper locking block assembly ring 6 contains multiple upper locking blocks 601. The upper locking blocks 601 are made of a soluble alloy material and are wedge-shaped. Multiple upper locking blocks 601 are arranged circumferentially along the cone 12. An upper guide groove 602 is provided on the upper end face of each upper locking block 601. The upper end face of the upper locking block 601 abuts against the lower end face of the push ring 4. The upper guide groove 602 and the lower guide rib 404 are correspondingly inserted into each other. The inner surface of the upper locking block 601 abuts against the upper conical section 1201. At least one anchoring tooth 7 is provided on the outer surface of the upper locking block 601. An outer hoop ring 5 is fitted over the upper locking block assembly ring 6. A limiting hoop ring 8 is connected to the lower end of the upper locking block assembly ring 6. The limiting hoop ring 8 is fitted over the upper conical section 1201. Both the outer hoop ring 5 and the limiting hoop ring 8 are made of a soluble alloy material. Figure 6 As shown.

[0035] The upper locking block 601 is made of low-strength soluble magnesium alloy. The inner surface of the upper locking block 601 mates with the cone 12. The cone angle of the inner surface of the upper locking block 601 is the same as the outer cone angle of the upper cone section 1201 of the cone 12. The lower guide rib 404 serves as a guide. The outer surface of the upper locking block 601 has a circular hole with a certain bevel for inserting the anchoring tooth 7. The upper locking blocks 601 are assembled into a ring-shaped upper locking block assembly 6 by multiple evenly distributed blocks on the circumference, and are positioned by the outer hoop ring 5 and the limiting hoop ring 8.

[0036] The number of upper locking blocks 601 in the upper locking block group ring 6 needs to be determined according to the outer diameter of the bridge plug. The number of upper locking blocks 601 can be 6 to 12, for example, a 10-block structure is adopted. The main function of the upper locking block 601 is to slide downward along the cone 12 and expand radially under the action of axial force, gradually opening the upper metal sealing ring 9, the first support ring 10 and the second support ring 11 until they are close to the inner wall of the sleeve 16. The anchoring teeth 7 initially bite into the inner wall of the sleeve 16, locking the position and the state of the upper metal sealing ring 9.

[0037] Both the outer clamping ring 5 and the limiting clamping ring 8 are made of soluble magnesium alloy with high elongation; they are mainly used to clamp several evenly distributed upper locking blocks 601 around the circumference; the limiting clamping ring 8 also plays a buffering role to prevent the upper locking blocks 601 from damaging the upper metal sealing ring 9 during expansion. The anchoring teeth 7 are cylindrical and can usually be made of high-strength or high-strength alloy steel or ceramic materials; they are mainly used after the bridge plug is set, the anchoring teeth 7 bite into the inner wall of the sleeve 16, and are one of the key components for the stable anchoring of the bridge plug.

[0038] In this embodiment, the upper metal sealing ring 9 has a wedge-shaped cross-section and is made of a soluble alloy material. The inner surface of the upper metal sealing ring 9 matches and abuts against the upper conical section 1201. The inner surface of the upper metal sealing ring 9 is provided with multiple inner grooves, and the outer surface of the upper metal sealing ring 9 is provided with multiple outer grooves. The multiple inner grooves and multiple outer grooves are arranged at intervals along the axis of the cone 12.

[0039] In this embodiment, the upper metal sealing ring 9 and the lower metal sealing ring 15 are symmetrical and mirror images of each other. The cross-section of the inner groove is V-shaped, and the opening of the V-shape faces the cone 12. The cross-section of the outer groove is rectangular. The material elongation of the upper metal sealing ring 9 and the lower metal sealing ring 15 is ≥20%. The surfaces of the upper metal sealing ring 9 and the lower metal sealing ring 15 are provided with a high-temperature anti-corrosion coating to ensure the stability of the wedge-shaped sealing ring under the high temperature and high pressure environment at the bottom of the well.

[0040] Both the upper metal sealing ring 9 and the lower metal sealing ring 15 are matched and connected to the cone 12. The multiple inner and outer grooves are mainly used to improve its overall elongation and deformation capacity. The upper metal sealing ring 9 and the lower metal sealing ring 15 can expand and deform along the conical surface of the cone 12 under the action of axial force. Finally, they wedge into the annular space between the cone 12 and the inner wall of the sleeve 16 to form a seal. As key components of the all-metal soluble bridge plug, the upper metal sealing ring 9 and the lower metal sealing ring 15 are usually made of soluble magnesium alloy material with high elongation. The upper metal sealing ring 9 and the lower metal sealing ring 15 constitute a two-stage sealing structure, which increases the effective sealing area and improves the sealing pressure bearing reliability and stability of the all-metal soluble bridge plug. The structures of the upper metal sealing ring 9 and the lower metal sealing ring 15 are exactly the same.

[0041] In this embodiment, the lower end of the upper metal sealing ring 9 is connected to a first support ring 10 and a second support ring 11 stacked together. Both the first support ring 10 and the second support ring 11 are sleeved on the upper conical section 1201. Both the first support ring 10 and the second support ring 11 are made of a soluble alloy material. U-shaped grooves 1001 are provided on the inner surfaces of both the first support ring 10 and the second support ring 11 to promote better C-shaped fracture. The U-shaped grooves 1001 of the first support ring 10 and the second support ring 11 are symmetrically distributed along the circumference of the cone 12. Figure 7 As shown.

[0042] The first support ring 10 and the second support ring 11 are both annular structures, made of high-strength soluble magnesium alloy. Both are matched and connected to the cone 12. The first support ring 10 and the second support ring 11 fit together to form a support ring assembly. The U-shaped groove 1001 of the first support ring 10 and the U-shaped groove 1001 of the second support ring 11 are symmetrically distributed at 180°, which better supports and protects the upper metal sealing ring 9, maintaining its integrity under pressure and preventing deformation; ultimately affecting the sealing performance of the bridge plug. The upper end of the cone 12 is provided with the support ring assembly consisting of the first support ring 10 and the second support ring 11, while the lower end of the cone 12 only has the first support ring 10. That is, the upper end of the lower metal sealing ring 15 is only connected to the first support ring 10, which fits snugly around the lower conical surface section 1202. The upper conical section 1201 is fitted with a second support ring 11, and the lower conical section 1202 is fitted with a first support ring 10, which are spaced apart vertically.

[0043] In this embodiment, the drop connector 14 has an annular structure and is made of a soluble alloy material. The drop connector 14 is sleeved on the lower end of the spindle 2. The upper end surface of the drop connector 14 is an upper conical surface with the top end facing upward and the bottom end facing downward. Multiple upper guide ribs 1401 are provided on the upper end surface of the drop connector 14. The multiple upper guide ribs 1401 are arranged at intervals along the circumference of the drop connector 14 and extend along the diameter direction of the drop connector 14.

[0044] The inner hole of the release connector 14 is threaded for threaded connection with the mandrel 2. Multiple upper guide ribs 1401 are provided on the upper end face of the release connector 14 for supporting and guiding the anchor block 1301. The lower end of the release connector 14 is chamfered (conical surface) for guiding. The type of internal thread of the release connector 14 can be rectangular thread, trapezoidal thread, or ordinary thread. The connection length of the internal thread of the release connector 14 directly determines the release force of the bridge plug in actual setting. As a key parameter, it needs to be calculated by thread shear force or obtained by a limited number of experiments.

[0045] In this embodiment, the anchoring block assembly 13 includes multiple anchoring blocks 1301. The anchoring blocks 1301 are made of a soluble alloy material and are wedge-shaped. The multiple anchoring blocks 1301 are arranged circumferentially along the cone 12. A lower guide groove 1302 is provided in the lower end face of the anchoring block 1301. The lower end face of the anchoring block 1301 matches and abuts against the upper end face of the release connector 14. The lower guide groove 1302 and the upper guide rib 1401 are paired one-to-one. The anchor block 1301 is fitted with a mating connector, its inner surface abutting against the lower conical section 1202. The outer surface of the anchor block 1301 has multiple anchoring teeth 7, spaced apart along the axial direction of the cone 12. An outer hoop ring 5 is fitted over the anchor block assembly ring 13, and a limiting hoop ring 8 is connected to the lower end of the anchor block assembly ring 13. The limiting hoop ring 8 is fitted over the lower conical section 1202. Both the outer hoop ring 5 and the limiting hoop ring 8 are made of a soluble alloy material. Figure 8 As shown.

[0046] The anchor block 1301 is made of high-strength, high-temperature resistant, soluble magnesium alloy. A lower guide groove 1302 is provided on the lower end face of the anchor block 1301 to cooperate with the upper guide rib 1401 of the release connector 14, providing support and guidance. The lower end face of the anchor block assembly ring 13 is tapered to provide a larger radial force to the anchor block 1301, which helps the anchor teeth 7 to better bite into the inner wall of the sleeve 16 under axial force during bridge plug setting.

[0047] The outer circumference of the anchor block 1301 is provided with three circular holes at a certain angle for inserting three anchor teeth 7; the anchor blocks 1301 are arranged in a circular ring 13 on the circumference in a way that multiple blocks are evenly distributed, and are positioned by the outer hoop ring 5 and the limiting hoop ring 8; thus forming a complete anchor body.

[0048] The number of anchor blocks 1301 in the anchor block group 13 needs to be determined according to the outer diameter of the bridge plug, and can be 6 to 12 blocks. For example, a 10-block structure is adopted. Its main function is to slide along the cone 12 and expand radially under the action of axial force, gradually opening the lower metal sealing ring 15 and the first support ring 10, and finally sticking to the inner wall of the sleeve 16. The anchoring teeth 7 initially bite into the inner wall of the sleeve 16, locking the setting position and the state of the lower metal sealing ring 15; realizing the initial anchoring at the specified position in the sleeve 16 after the bridge plug is released and set.

[0049] The structure of anchor block 1301 is similar to that of upper locking block 601, the main difference being an increased length, more anchoring teeth 7, and an increased lower end cone angle. Specifically, anchor block 1301... Figure 1 The length in the vertical direction is greater than the length of the upper locking block 601, and the number of anchoring teeth 7 on the anchoring block 1301 is greater than the number of anchoring teeth 7 on the upper locking block 601. The apex angle of the cone corresponding to the lower end face of the anchoring block group ring 13 is greater than the apex angle of the cone corresponding to the upper end face of the upper locking block group ring 6.

[0050] The dual-stage sealed metal soluble bridge plug also includes a soluble ball 17 and a pusher cylinder 1. The soluble ball 17 is spherical and made of a fast-dissolving material. The diameter of the soluble ball 17 depends on the inner diameter of the cone 12. After the bridge plug is set downhole, the soluble ball 17 finally adheres tightly to the annular conical setting surface 1203 of the cone 12, thus sealing the inner hole. The pusher cylinder 1 is a thin-walled cylindrical shape. The lower end of the pusher cylinder 1 is close to the upper side of the pusher ring 4. The lower end of the pusher cylinder 1 has four circumferentially distributed screw holes for installing the limit screws 3. The upper end of the pusher cylinder 1 can be connected to the standard setting tool (external tool) when the bridge plug is lowered into the well, which transmits axial loads.

[0051] The working process of the dual-stage sealed metal soluble bridge plug is described below.

[0052] The dual-stage sealed soluble metal bridge plug's downhole setting, anchoring, and pressure-bearing process involves first using a standard setting tool on the lowering tool string to apply a certain setting force, releasing the bridge plug and setting it at a designated position within the casing 16. The anchoring block ring 13 radially expands and adheres tightly to the inner wall of the casing 16, while the anchoring teeth 7 bite into the inner wall of the casing 16 to form initial anchoring. Then, during fracturing operations, as the pressure inside the wellbore continues to rise, the anchoring teeth 7 further bite into the inner wall of the casing, maintaining the bridge plug's anchoring state towards stability, as detailed below:

[0053] 1. The drop-off setting seal of the dual-stage sealed metal soluble bridge plug

[0054] like Figure 1 As shown, the upper end of the mandrel 2 and the upper end of the push cylinder 1 are respectively connected to the inner and outer tools of the standard setting tool by threads. By adjusting the distance of the thread engagement, the push cylinder 1 is axially pressed against the upper end face of the push ring 4 to ensure that the components between the push ring 4 of the bridge plug and the release connector 14 are tightly fitted. Then, the four limit screws 3 at the lower end of the push cylinder 1 are tightened to ensure that the push cylinder 1 and the push ring 4 will not separate.

[0055] When the setting tool is working, the outer tool provides an axial downward thrust to the push cylinder 1. Simultaneously, as the push cylinder 1 moves downward axially, under the combined action of the push ring 4 and the release connector 14, the upper locking block ring 6, the limiting ring 8, the upper metal sealing ring 9, the first support ring 10, the second support ring 11, and the anchoring block ring 13 at both ends of the cone 12 all exhibit a tendency to expand along the conical surface. Furthermore, under the action of the conical surface of the cone 12, a portion of the axial force is converted into radial force. When the axial thrust reaches a certain value, the outer rings 5 ​​within the outer grooves of the upper locking block ring 6 and the anchoring block ring 13 break successively, subsequently accelerating their expansion until they adhere tightly to the inner wall of the sleeve 16, locking the bridge plug in its setting position. After the bridge plug is locked, further, under the axial force provided by the setting tool, the axial pressure on the mandrel 2 instantly shears off the internal thread of the release connector 14, completing the release setting of the bridge plug. After the set-off is completed, the pusher 1, pusher ring 4, and mandrel 2 are removed from the wellhead along with the set-off tool (internal tool) and can be reused.

[0056] 2. The sealing pressure bearing capacity of the dual-stage sealed metal soluble bridge plug

[0057] like Figure 2 As shown, the dual-stage sealing metal soluble bridge plug completes initial anchoring and setting at a designated location downhole. After all components are locked, according to the fracturing operation requirements, soluble balls 17 are dropped from the wellhead and continuously pumped to the annular conical setting surface 1203 at the upper end of the cone 12 of the bridge plug at the bottom of the well, completing the setting and sealing the inner hole of the bridge plug; thus achieving overall sealing of the wellbore inside the casing. Furthermore, during the fracturing operation, as the pressure inside the wellbore continues to rise, the anchoring teeth 7 further bite into the inner wall of the casing, achieving stable anchoring of the bridge plug; and further compacting the metal sealing ring. Under the support and protection of the inner, outer, and anchoring blocks, the metal sealing ring is theoretically in a state of increasing tightness with increasing pressure; thereby establishing an effective seal inside the wellbore and completing the pressure-bearing and fracturing operation for a certain period of time.

[0058] 3. Rapid dissolution of the dual-stage sealed metal soluble bridge plug

[0059] After fracturing operations are completed, the bridge plug can rapidly dissolve on its own under certain temperature and salinity conditions at the bottom of the well. As the dissolution process continues, the various components of the bridge plug will detach from the inner wall of the casing, eventually dissolving completely into fine powdery residue. The higher the bottom-hole temperature and salinity, the faster the dissolution rate and the shorter the time required for complete dissolution. The materials used for the components of the dual-stage sealed metal soluble bridge plug can all be existing materials; "soluble" means it can dissolve in water.

[0060] For ease of understanding and description, this invention uses absolute positional relationships for description. Unless otherwise specified, the directional term "above" indicates... Figure 1The present invention is described from the perspective of the reader or user, but the above directional terms should not be understood or interpreted as limiting the scope of protection of the present invention.

[0061] The above description is merely a specific embodiment of the present invention and should not be construed as limiting the scope of the invention. Therefore, any substitution of equivalent components or equivalent changes and modifications made within the scope of protection of this patent should still fall within the scope of this patent. Furthermore, the technical features, technical solutions, and embodiments of the present invention can be freely combined and used together.

Claims

1. A two-stage sealed metal soluble bridge plug, characterized in that, The dual-stage sealed metal soluble bridge plug includes an inner and outer mandrel (2) and a cone (12). The outer surface of the cone (12) has an upper conical section (1201) and a lower conical section (1202) arranged vertically. The top end of the upper conical section (1201) faces upward and the bottom end faces downward. The upper conical section (1201) is fitted with an upper locking block ring (6) and an upper metal sealing ring (9) arranged vertically. The top end of the lower conical section (1202) faces downward and the bottom end faces upward. The lower conical section (1202) is fitted with an upper locking block ring (6) and an upper metal sealing ring (9) arranged vertically. The lower metal sealing ring (15) and the anchoring block ring (13) are arranged vertically. The lower end of the spindle (2) is connected to the release connector (14). The anchoring block ring (13) and the release connector (14) are connected vertically. When the upper locking block ring (6) moves downward relative to the spindle (2), the cone (12) can also move downward relative to the spindle (2). The upper locking block ring (6), the upper metal sealing ring (9), the lower metal sealing ring (15) and the anchoring block ring (13) can all expand radially. The upper metal sealing ring (9) has a wedge-shaped cross section. The upper metal sealing ring (9) is made of a soluble alloy material. The inner surface of the upper metal sealing ring (9) matches and abuts against the upper conical section (1201). The inner surface of the upper metal sealing ring (9) is provided with multiple inner grooves, and the outer surface of the upper metal sealing ring (9) is provided with multiple outer grooves. The multiple inner grooves and multiple outer grooves are arranged at intervals along the axis of the cone (12). The upper metal sealing ring (9) and the lower metal sealing ring (15) are symmetrical and mirror images of each other. The cross-section of the inner groove is V-shaped, and the opening of the V-shape faces the cone (12). The cross-section of the outer groove is rectangular. The material elongation of the upper metal sealing ring (9) and the lower metal sealing ring (15) is ≥20%. The lower end of the upper locking block ring (6) is connected to an upper limit hoop ring, which is sleeved outside the upper conical section (1201); The lower end of the upper metal sealing ring (9) is connected to a first support ring (10) and a second support ring (11) that are stacked on top of each other. The first support ring (10) and the second support ring (11) are both sleeved on the upper conical section (1201). The upper end of the anchor block assembly ring (13) is connected to a lower limit hoop ring, which is sleeved on the lower conical surface section (1202).

2. The dual-stage sealing metal soluble bridge plug according to claim 1, characterized in that, The mandrel (2) is an upright tubular structure. The outer surface of the mandrel (2) contains a first large diameter section (201), a second large diameter section (202), a first small diameter section (203), and a second small diameter section (204) arranged sequentially from top to bottom. The outer diameters of the first large diameter section (201), the second large diameter section (202), the first small diameter section (203), and the second small diameter section (204) decrease sequentially. The cone (12) is an upright cylindrical structure. The upper cone section (1201) and the lower cone section (1202) are symmetrical and mirror images of each other.

3. The dual-stage sealing metal soluble bridge plug according to claim 2, characterized in that, The first major diameter section (201) has an internal thread, and the cone (12) is fitted outside the first minor diameter section (203). The second major diameter section (202) and the first minor diameter section (203) have an annular conical outer transition section (205). The upper end of the cone (12) has an annular conical seat cover (1203). The annular conical outer transition section (205) matches and abuts against the annular conical seat cover (1203). The second minor diameter section (204) is connected to the internal and external threads of the drop-off connector (14). The external thread of the second minor diameter section (204) can cut off the internal thread of the drop-off connector (14).

4. The dual-stage sealing metal soluble bridge plug according to claim 1, characterized in that, The dual-stage sealed metal soluble bridge plug also includes a push ring (4), which is sleeved on the outside of the mandrel (2). The push ring (4) is connected to the upper locking block ring (6) vertically. The outer surface of the push ring (4) has an outer small diameter section (401) and an outer large diameter section (402) arranged vertically. The lower part of the outer small diameter section (401) is provided with an annular groove (403). The lower end face of the push ring (4) is a lower conical surface. The top end of the lower conical surface faces downward and the bottom end faces upward. The lower end face of the push ring (4) is provided with multiple lower guide ribs (404). The multiple lower guide ribs (404) are arranged at intervals along the circumference of the push ring (4). The lower guide ribs (404) extend along the diameter direction of the push ring (4).

5. The dual-stage sealing metal soluble bridge plug according to claim 4, characterized in that, The upper locking block assembly ring (6) contains multiple upper locking blocks (601). The upper locking blocks (601) are made of soluble alloy material. The upper locking blocks (601) are wedge-shaped blocks. Multiple upper locking blocks (601) are arranged circumferentially along the cone (12). The upper end face of the upper locking block (601) is provided with an upper guide groove (602). The upper end face of the upper locking block (601) matches and abuts with the lower end face of the push ring (4). The upper guide groove (602) and the lower guide rib (404) are matched and inserted one by one. The inner surface of the upper locking block (601) matches and abuts with the upper cone surface section (1201). The outer surface of the upper locking block (601) is provided with at least one anchoring tooth (7). The upper locking block assembly ring (6) is covered with an outer hoop ring (5). The outer hoop ring (5) and the upper limit hoop ring are both made of soluble alloy material.

6. The dual-stage sealing metal soluble bridge plug according to claim 1, characterized in that, Both the upper metal sealing ring (9) and the lower metal sealing ring (15) are coated with a high-temperature corrosion resistant coating.

7. The dual-stage sealing metal soluble bridge plug according to claim 1, characterized in that, The first support ring (10) and the second support ring (11) are both made of soluble alloy material. The inner surface of the first support ring (10) and the inner surface of the second support ring (11) are provided with U-shaped grooves (1001). The U-shaped grooves (1001) of the first support ring (10) and the U-shaped grooves (1001) of the second support ring (11) are symmetrically distributed along the circumference of the cone (12).

8. The dual-stage sealing metal soluble bridge plug according to claim 1, characterized in that, The drop connector (14) has a ring structure and is made of a soluble alloy material. The drop connector (14) is sleeved on the lower end of the mandrel (2). The upper end surface of the drop connector (14) is an upper conical surface with the top end facing up and the bottom end facing down. Multiple upper guide ribs (1401) are provided on the upper end surface of the drop connector (14). The multiple upper guide ribs (1401) are arranged at intervals along the circumference of the drop connector (14) and extend along the diameter direction of the drop connector (14).

9. The dual-stage sealing metal soluble bridge plug according to claim 8, characterized in that, The anchoring block assembly (13) contains multiple anchoring blocks (1301). The anchoring blocks (1301) are made of a soluble alloy material. The anchoring blocks (1301) are wedge-shaped. Multiple anchoring blocks (1301) are arranged circumferentially along the cone (12). The lower end face of the anchoring block (1301) is provided with a lower guide groove (1302). The lower end face of the anchoring block (1301) matches and abuts against the upper end face of the release connector (14). The lower guide groove (1302) 302) Matches and inserts with the upper guide rib (1401) one by one. The inner surface of the anchor block (1301) matches and abuts with the lower conical section (1202). The outer surface of the anchor block (1301) is provided with multiple anchor teeth (7). The multiple anchor teeth (7) are arranged at intervals along the axial direction of the cone (12). The anchor block assembly ring (13) is covered with an outer hoop ring (5). The outer hoop ring (5) and the lower limit hoop ring are both made of soluble alloy material.

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