Large-drift-diameter well cementation sliding sleeve system with double-key intelligent switch

Abstract

The invention discloses a double-key intelligent switch large-drift-diameter well cementation sliding sleeve system, which relates to the technical field of oil and gas well fracturing and comprises a plurality of soluble plungers and a plurality of sliding sleeves. The soluble plunger comprises a soluble ball, a ball seat, an elastic tube and a front seat, the top of the ball seat is open, the inner wall of the ball seat is used for clamping the soluble ball, the outer wall of the ball seat is connected with the top end of the elastic tube through a plurality of first pins, a plurality of annular grooves are formed in the outer wall of the ball seat, sealing rings are arranged in the annular grooves and located above the elastic tube, and the front seat is connected to the bottom end of the elastic tube. Two elastic rings and a plurality of strip-shaped grooves penetrating through the elastic tube are arranged on the outer wall of the elastic tube, each elastic ring is divided into a plurality of elastic pieces by the strip-shaped grooves, the bottom ends of the elastic pieces are of acute angle structures, and the top ends of the elastic pieces are of obtuse angle structures; two clamping grooves are formed in the inner wall of the sliding sleeve, and the bottom ends of the clamping grooves are of an acute angle structure and used for clamping the corresponding elastic pieces on the corresponding soluble plungers. And through coding of a double-key structure, the stage number of fracturing grading can be greatly increased.

Description

Technical Field

[0001] This invention relates to the field of oil and gas well fracturing technology, and in particular to a dual-key intelligent switch large-diameter cementing sliding sleeve system. Background Technology

[0002] Multi-stage fracturing is a commonly used technique in oil and gas well fracturing operations, aimed at improving oil and gas recovery rates.

[0003] There are two key factors for successful fracturing: first, sealing. If the structural design, material selection, or installation of the sliding sleeve and the soluble plunger are improper, the seal between the sliding sleeve and the soluble plunger will not be tight enough, affecting the fracturing effect; second, pressure bearing capacity. The soluble plunger is stuck inside the sliding sleeve, and the pressure is mainly borne by the points where the soluble plunger is stuck. If the structural design of the sliding sleeve and the soluble plunger is improper, it will not be able to withstand the stress under high pressure, which will lead to the soluble plunger rupture or failure.

[0004] CN119288418A provides a full-bore cementing and fracturing sliding sleeve system. Each sliding sleeve has a different groove length. The sliding sleeves are inserted into the wellbore in order of progressively increasing groove length from top to bottom. Then, the corresponding soluble plungers are inserted into the wellbore in sequence, ensuring that the soluble plungers are locked in the sliding sleeves at specific positions. By squeezing the rubber sleeve, the rubber sleeve expands and tightly adheres to the inner wall of the sliding sleeve, achieving an effective seal. The soluble plunger has a pressure resistance of 70MPa. First, it bears pressure through an elastic plate, the bottom of which can face downwards, increasing the pressure resistance. Second, the slips open and lock tightly against the inner wall of the sliding sleeve, which also plays a role in bearing pressure.

[0005] However, the above solution still has the following problems: First, the sealing structure is relatively complex, which has a certain impact on reliability and construction efficiency, and needs to be further simplified and optimized; Second, relying on a single key structure to achieve graded operation has a limited number of distinguishable grades, which is difficult to meet the needs of more refined and multi-stage fracturing. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a dual-key intelligent switch large-diameter cementing sliding sleeve system, which optimizes the sealing structure and increases the number of stages.

[0007] In order to achieve the objective of this invention, the following solution is proposed: A dual-key intelligent switch large-diameter cementing sliding sleeve system includes multiple soluble plungers and multiple sliding sleeves.

[0008] The soluble plunger includes a soluble ball, a ball seat, an elastic tube, and a front seat. The ball seat has an opening at the top, and its inner wall is used to hold the soluble ball. The outer wall of the ball seat is connected to the top of the elastic tube by multiple first pins. The outer wall of the ball seat has multiple annular grooves, and a sealing ring is installed in the annular groove. The sealing ring is located above the elastic tube. The front seat is connected to the bottom of the elastic tube. The outer wall of the elastic tube has two elastic rings and multiple strip grooves that penetrate the elastic tube. The strip grooves divide each elastic ring into multiple elastic pieces. The bottom of the elastic piece has an acute angle structure, and the top of the elastic piece has an obtuse angle structure. The inner wall of the sliding sleeve is provided with two slots, the bottom of which has an acute angle structure, used to lock the corresponding elastic plate on the corresponding soluble plunger.

[0009] Furthermore, the soluble plunger also includes slips, which are fitted outside the ball seat. The outer wall of the ball seat and the inner wall of the slips are adapted to each other by an inclined surface, and the sealing ring on the outer wall of the ball seat is located above the slips.

[0010] Furthermore, the outer wall of the kava has two rings of inlaid pillars, and the top of the kava has multiple cuts.

[0011] Furthermore, the sliding sleeve includes an outer tube and an inner tube disposed therein. The outer tube includes a first sleeve, a second sleeve, and a third sleeve connected in sequence. The inner tube includes a fourth sleeve and a fifth sleeve connected in sequence. The outer wall of the fourth sleeve is tightly attached to the inner wall of the second sleeve. There is a gap between the outer wall of the fifth sleeve and the inner wall of the second sleeve. The outer wall of the fifth sleeve is tightly attached to the inner wall of the third sleeve. The second sleeve is fixedly connected to the fourth sleeve by a plurality of second pins. The second sleeve also has a plurality of fracturing holes arranged in a circumferential array. The fracturing holes are located between the first sleeve and the second pins. Two slots are provided on the inner wall of the fourth sleeve.

[0012] Furthermore, the inner diameter of the upper part of the third sleeve is larger than that of the lower part. When the second pin is sheared and the inner tube moves down, the change in diameter of the inner diameter of the third sleeve is used to support the fifth sleeve.

[0013] Furthermore, a sealing ring is provided between the inner wall of the first sleeve and the inner wall of the second sleeve, a sealing ring is provided between the inner wall of the third sleeve and the inner wall of the second sleeve, and three sealing rings are provided between the inner wall of the fourth sleeve and the inner wall of the second sleeve.

[0014] Furthermore, the inner wall of the second sleeve is provided with an annular shearing groove located in the gap, and the outer wall of the fourth sleeve is provided with an annular groove containing two shearing C-rings. When the second pin is sheared and the inner tube moves downward, the shearing groove is used to accommodate the shearing C-rings.

[0015] Furthermore, the inner wall of the fourth sleeve is circumferentially arrayed with multiple guide grooves, which connect the two slots.

[0016] Furthermore, the sliding sleeve includes a sixth sleeve, a seventh sleeve, an eighth sleeve, and a ninth sleeve. The outer wall of the sixth sleeve is connected to the inner wall of the top of the seventh sleeve. The inner wall of the bottom of the seventh sleeve is in close contact with the outer wall of the top of the eighth sleeve. The inner wall of the top of the eighth sleeve is connected to the outer wall of the bottom of the sixth sleeve. The ninth sleeve is located in the gap between the sixth and seventh sleeves and is connected to the outer wall of the sixth sleeve by multiple third pins. The seventh sleeve has multiple fracturing holes arranged in a circumferential array, and the fracturing holes are located below the third pins. The sixth sleeve has multiple first through holes and multiple second through holes arranged in a circumferential manner. The first through holes connect the gap and are located higher than the ninth sleeve. The second through holes correspond to the fracturing holes. Both slots are provided on the inner wall of the eighth sleeve.

[0017] Furthermore, the outer wall of the ninth casing is provided with two annular grooves, located above and below the fracturing hole respectively, and the inner wall of the ninth casing is provided with two annular grooves, located above and below the fracturing hole respectively. Each of these four annular grooves is provided with a sealing ring.

[0018] Furthermore, the outer wall of the ninth sleeve is provided with a third annular groove, which contains two shearing C-rings. The inner wall of the seventh sleeve is provided with an annular shearing groove. When the third pin is sheared and the ninth sleeve moves down, the shearing groove is used to accommodate the shearing C-rings.

[0019] Furthermore, the inner wall of the elastic tube is provided with an inner ring, which is located within the range corresponding to the two slots. The top surface of the inner ring is set as a first inclined surface, the bottom end of the ball seat extends to the inner ring, and the outer wall of the bottom end of the ball seat is set as a second inclined surface that matches the first inclined surface. The strip groove divides the inner ring into multiple elastic blocks.

[0020] The beneficial effects of this invention are as follows: 1. Soluble Plunger: Available in products adaptable to different temperature ranges from 38℃ to 178℃ (100F-350F); various material combinations are available to meet the requirements of different blocks; pressure ratings of 70MPa and 105MPa are available, with a simplified design and integrated anti-premature setting design; 100% soluble material, completely dissolved within 5 days, with the dissolution time adjustable according to site requirements; finely treated metal surface with coating treatment, including acid resistance, water solubility, corrosion protection, and surface spraying, suitable for wells requiring acid immersion; applicable to all current casing steel grades, such as P110 / 125 / 140; maximized inner diameter design facilitates post-fracturing backflow without affecting production.

[0021] 2. Sliding Sleeve: No perforation required, fracturing operations can be completed continuously in one trip; products are available to adapt to different temperature ranges from 38℃ to 178℃ (100F-350F); the flow diameter is maintained after fracturing, facilitating subsequent well workover operations; various material combination designs are available to meet the requirements of different blocks; the sliding sleeve can be opened and closed multiple times: according to production needs, the sliding sleeve can be closed and opened at any time, greatly enhancing its practicality; the sliding sleeve has a large flow channel area, suitable for high-volume fracturing operations; the fracturing hole design is conducive to breaking the cement sheath in the near-wellbore zone; tools are available in 70MPa and 105MPa grades to meet the requirements of different well conditions; suitable for open-hole staged fracturing and cementing staged fracturing.

[0022] 3. It can eliminate the need for slips and rubber sleeves, using metal seals; it transforms the two-layer sliding sleeve structure into a three-layer structure, effectively preventing premature opening of the sliding sleeve during the cementing stage; the soluble plunger combined with a centralizer effectively guides the elastic plate into the designated target sliding sleeve; it minimizes the tool length and reduces tool rigidity, facilitating tubing insertion into the well; the dual-key structure makes tool coding more flexible and versatile, truly achieving unlimited-level fracturing sliding sleeves; the minimalist soluble component design effectively avoids secondary cross-linking problems when the soluble component dissolves downhole. Attached Figure Description

[0023] Figure 1 A cross-sectional view of the sliding sleeve and soluble plunger of Example 1 is shown; Figure 2 A cross-sectional view of the sliding sleeve of Embodiment 1 is shown; Figure 3 An external structural diagram of the soluble plunger of Example 1 is shown; Figure 4 An external structural diagram of the sliding sleeve of Embodiment 1 is shown; Figure 5 The internal structure diagram of the fourth sleeve in Embodiment 1 is shown; Figure 6 A structural diagram of Example 1 is shown; Figure 7 The following diagram shows the results of the pressure resistance test of the sliding sleeve in Example 1; Figure 8 The following graph shows the pressure resistance test results of the soluble plunger in Example 1; Figure 9 A cross-sectional view of the sliding sleeve and soluble plunger of Example 2 is shown; Figure 10 A cross-sectional view of the soluble plunger of Example 2 is shown. Detailed Implementation

[0024] Example 1 like Figure 1 As shown, this embodiment provides a dual-key intelligent switch large-diameter cementing sliding sleeve system, including multiple soluble plungers 2 and multiple sliding sleeves 1.

[0025] Specifically, such as Figure 1 , Figure 3 As shown, the soluble plunger 2 includes a soluble ball 21, a slip 22, a ball seat 23, an elastic tube 24, and a front seat 25. The ball seat 23 has an opening at the top, and its inner wall is used to hold the soluble ball 21. The bottom end of the ball seat 23 is connected to the top end of the elastic tube 24 via multiple first pins 231. The slip 22 is fitted onto the ball seat 23, and the outer wall of the ball seat 23 and the inner wall of the slip 22 are adapted to each other via inclined surfaces. The outer wall of the ball seat 23 has multiple annular grooves, and a sealing ring is installed in each annular groove, with the sealing ring located above the slip 22. The seat 25 is connected to the bottom end of the elastic tube 24. The two can be fixedly connected by thread or by pin. The outer wall of the elastic tube 24 is provided with an elastic ring and multiple strip grooves 242. The two elastic rings have different or the same length. The length refers to the dimension along the central axis of the soluble plunger 2. The multiple strip grooves 242 all penetrate the side wall of the elastic tube 24. The strip grooves 242 divide each elastic ring into multiple elastic pieces 241. The bottom end of the elastic piece 241 has an acute angle structure and the top end has an obtuse angle structure.

[0026] More specifically, such as Figure 3 , Figure 6 As shown, the outer wall of the kava 22 is provided with two rings of inlaid pillars 221, and the top of the kava 22 is provided with multiple cuts 222.

[0027] Specifically, such as Figure 2 As shown, the inner wall of the sliding sleeve 1 is provided with two annular grooves 141. The bottom end of the grooves 141 has an acute angle structure, which is used to lock the corresponding elastic plate 241 on the soluble plunger 2. According to different combinations of the length of the grooves 141, multiple sliding sleeves 1 are assembled together in a specific order and then placed into the well. Based on the principle that the elastic plate 241 can contract when subjected to compression force and return to its original shape when the compression force is removed, the soluble plunger 2 is put into the well, and the soluble plunger 2 will automatically lock into the corresponding sliding sleeve 1.

[0028] It should be noted that: CN119288418A provides a full-bore cementing and fracturing sliding sleeve system that relies on a single key structure to achieve staged operation, which limits the number of stages that can be distinguished; the present invention relies on a dual-key structure, which greatly increases the number of stages.

[0029] More specifically, such as Figure 2 , Figure 4As shown, the sliding sleeve 1 includes an outer tube and an inner tube disposed therein. The outer tube includes a first sleeve 11, a second sleeve 12, and a third sleeve 13 connected in sequence. These three can be connected by threads or by pins. The inner tube includes a fourth sleeve 14 and a fifth sleeve 15 connected in sequence. Similarly, these two can be connected by threads or by pins. The outer wall of the fourth sleeve 14 is tightly attached to the inner wall of the second sleeve 12, and the second sleeve 12 is fixedly connected by multiple second pins 121. The fourth sleeve 14 is connected to the second sleeve 12, which also has a plurality of fracturing holes 122 arranged in a circumferential array. At the height position, the fracturing holes 122 are located between the first sleeve 11 and the second pin 121. Two slots 141 are provided on the inner wall of the fourth sleeve 14. In the initial state, the fracturing holes 122 are closed by the fourth sleeve 14. There is a gap 16 between the outer wall of the fifth sleeve 15 and the inner wall of the second sleeve 12. The function of the gap 16 is to leave corresponding space for the fourth sleeve 14 to move down. The outer wall of the bottom end of the fifth sleeve 15 is close to the inner wall of the third sleeve 13.

[0030] More specifically, such as Figure 2 As shown, the inner diameter of the upper part of the third sleeve 13 is larger than the inner diameter of the lower part. When the second pin 121 is sheared and the inner tube moves down, the diameter change point of the inner diameter of the third sleeve 13 is used to support the fifth sleeve 15, which can prevent the fifth sleeve 15 from falling off.

[0031] More specifically, such as Figure 2 As shown, the inner wall of the second sleeve 12 is provided with an annular shearing groove 123, which is located at the gap 16. The outer wall of the fourth sleeve 14 is provided with an annular groove, in which two shearing C-rings 143 are provided. When the second pin 121 is sheared and the inner tube moves down, the two shearing C-rings 143 move down with it. The shearing groove 123 is used to accommodate the shearing C-rings 143.

[0032] More specifically, such as Figure 2 As shown, a sealing ring is provided between the inner walls of the first sleeve 11 and the second sleeve 12, a sealing ring is provided between the third sleeve 13 and the inner wall of the second sleeve 12, and three sealing rings are provided between the fourth sleeve 14 and the inner wall of the second sleeve 12. The positions of these three sealing rings are respectively: above the fracturing hole 122, between the fracturing hole 122 and the second pin 121, and between the second pin 121 and the shear C ring 143.

[0033] More specifically, such as Figure 5 As shown, the inner wall of the fourth sleeve 14 has a circumferential array of multiple guide grooves 142. The guide grooves 142 are connected to two slots 141. The function of the guide grooves 142 is to prevent cement from being stuck in the sliding sleeve 1.

[0034] How to use: Assemble multiple sliding sleeves 1 in a specific order; The assembled sliding sleeves 1 are lowered into the oil and gas layer in the well; After cementing the well, the soluble plungers 2 are lowered in a specific order and locked into the corresponding sliding sleeves 1. Pressurize the soluble plunger 2, and the soluble ball 21 presses down on the ball seat 23, first cutting off the first pin 231. The ball seat 23 and the soluble ball 21 move down, and the outer wall of the ball seat 23 gradually squeezes the slip 22, causing the slip 22 to open and clamp the inner wall of the fourth sleeve 14. Pressurize the soluble plunger 2 continuously, and the elastic plate 241 and the slip 22 will exert a downward force on the fourth sleeve 14, causing the second pin 121 to be sheared. The entire inner tube and the soluble plunger 2 move down as a whole. During this process, the fracturing hole 122 is gradually opened, and the shearing C ring 143 moves down to the shearing groove 123. Then the shearing C ring 143 springs open and is positioned in the corresponding shearing groove 123. After fracturing hole 122 was opened, multi-stage fracturing began. After fracturing is completed, dissolve the soluble plunger 2.

[0035] Regarding sealing: This invention achieves sealing through two sealing rings on the outer wall of the ball seat 23, simplifying the sealing method.

[0036] Regarding pressure bearing: First, pressure is borne by the elastic sheet 241, with the bottom end of the elastic sheet 241 inserted downward into the slot 141, which improves the pressure bearing capacity; second, the slip 22 opens and clamps the inner wall of the fourth sleeve 14, which can also play a role in pressure bearing.

[0037] Regarding tiers: Compared to the single-key structure, the dual-key structure greatly increases the number of tiers.

[0038] Normal passage conditions for the soluble plunger 2: For ease of distinction, the lengths of the two elastic sheets 241 are described as A1 and A2, respectively, and the lengths of the two slots 141 are described as B1 and B2, respectively. When A1 is greater than B1 or A2 is greater than B2, and one of these conditions is met, the soluble plunger 2 can pass smoothly through the sliding sleeve 1 without triggering any mechanical action.

[0039] Position recognition conditions: When A1 is less than B1 and A2 is less than B2, and both conditions are met at the same time, the elastic plate 241 of the soluble plunger 2 will pop out and get stuck in the slot 141 of the sliding sleeve 1, and the pump pressure will increase; if the displacement is further increased, the pump pressure will increase, shearing the first pin 231 and the second pin 121, and opening the fracturing hole 122 of the sliding sleeve 1.

[0040] Figure 7 The diagram shows the pressure resistance test results of the sliding sleeve 1. The test results show that the body pressure resistance of the sliding sleeve 1 meets the requirement of 70MPa. Figure 8The figure shows the pressure resistance test results of the soluble plunger 2. The soluble plunger 2 can withstand a pressure of 70MPa and stabilize the pressure for 15 minutes, which achieves the test objective and meets the on-site construction requirements.

[0041] By adjusting the length of the elastic plate 241, precise control of multi-layer fracturing in oil and gas wells is achieved. When the size of the elastic plate 241 meets the passage conditions, the soluble plunger 2 smoothly passes through the sliding sleeve 1. When the size of the elastic plate 241 meets the setting conditions, the soluble plunger 2 sets at the sliding sleeve 1. When the soluble plunger 2 sets into the sliding sleeve 1, the pressure increases due to the double sealing rings on the ball seat 23. When the pressure reaches the setting initiation shear force of the soluble plunger 2 (adjustable from 1 to 3 tons), the sliding sleeve 1 is directly set and opened. This design not only improves the flexibility and accuracy of fracturing operations but also reduces operating costs and complexity.

[0042] Example 2 like Figure 9 , Figure 10 As shown, this embodiment provides a dual-key intelligent switch large-diameter cementing sliding sleeve system, including multiple soluble plungers 2 and multiple sliding sleeves 1. The sliding sleeve 1 in this embodiment 2 has a different structure than the sliding sleeve 1 in embodiment 1, the difference being: Specifically, such as Figure 9 As shown, the sliding sleeve 1 includes a sixth sleeve 31, a seventh sleeve 32, an eighth sleeve 33, and a ninth sleeve 34. The outer wall of the sixth sleeve 31 is threaded to the inner wall of the top end of the seventh sleeve 32, and a sealing ring is provided at the connection between the two. The inner wall of the bottom end of the seventh sleeve 32 is tightly attached to the outer wall of the top end of the eighth sleeve 33, and multiple sealing rings are provided between the two. The inner wall of the top end of the eighth sleeve 33 is threaded to the outer wall of the bottom end of the sixth sleeve 31, and a sealing ring is provided at the connection between the two. The ninth sleeve 34 is located in the gap 313 between the sixth sleeve 31 and the seventh sleeve 32, and the ninth sleeve 34 is threaded to the inner wall of the top end of the seventh sleeve 32. The ninth sleeve 34 is connected to the outer wall of the sixth sleeve 31 by multiple third pins 341. The seventh sleeve 32 has multiple fracturing holes 122 arranged in a circumferential array. The fracturing holes 122 are located below the third pins 341. In the initial state, the ninth sleeve 34 closes the fracturing holes 122. The sixth sleeve 31 has multiple first through holes 311 and multiple second through holes 312 arranged in a circumferential array. The first through holes 311 connect to the gap 313 and are located higher than the ninth sleeve 34. The second through holes 312 are located corresponding to the fracturing holes 122. Both slots 141 are located on the inner wall of the eighth sleeve 33.

[0043] Specifically, such as Figure 9 As shown, the outer wall of the ninth sleeve 34 is provided with two annular grooves, located above and below the fracturing hole 122 respectively. The inner wall of the ninth sleeve 34 is also provided with two annular grooves, located above and below the fracturing hole 122 respectively. Each of these four annular grooves is provided with a sealing ring.

[0044] Specifically, such as Figure 9As shown, the outer wall of the ninth sleeve 34 is also provided with a third annular groove, which contains two shearing C-rings 143. The inner wall of the seventh sleeve 32 is provided with an annular shearing groove 123, which is located at the gap 313. When the third pin 341 is sheared and the ninth sleeve 34 moves down, the shearing groove 123 is used to accommodate the shearing C-rings 143.

[0045] Based on Example 1, Example 2 optimizes the structure of the soluble plunger 2: as follows Figure 9 , Figure 10 As shown, the inner wall of the elastic tube 24 is provided with an inner ring, which is located within the range corresponding to the two slots 141. The top surface of the inner ring is set as a first inclined surface. The bottom end of the ball seat 23 extends to the inner ring. The outer wall of the bottom end of the ball seat 23 is set as a second inclined surface that matches the first inclined surface. The strip groove 242 divides the inner ring into multiple elastic blocks 243.

[0046] like Figure 9 , Figure 10 As shown, the outer wall of the elastic tube 24 is provided with an outer ring, which is located below the two elastic rings. The strip groove 242 divides the outer ring into multiple straightening pieces. The function of the straightening pieces is to effectively guide the elastic pieces 241 into the slots 141 of the designated target sliding sleeve 1. At the position corresponding to the straightening pieces, the inner wall of the eighth sleeve 33 is provided with a clearance groove. When the elastic piece 241 is engaged in the slot 141, the clearance groove on the inner wall of the eighth sleeve 33 is used to accommodate the straightening pieces.

[0047] How to use: Assemble multiple sliding sleeves 1 in a specific order; The assembled sliding sleeves 1 are lowered into the oil and gas layer in the well; After cementing the well, the soluble plungers 2 are lowered in a specific order and locked into the corresponding sliding sleeves 1. Pressurizing the soluble plunger 2 causes the soluble ball 21 to press down on the ball seat 23. Since the elastic plate 241 is stuck in the groove 141, the elastic tube 24 will not move down. Continuous pressurization will shear off the first pin 231. Then the ball seat 23 and the soluble ball 21 move down. The second inclined surface at the bottom of the ball seat 23 squeezes the elastic block 243, causing the elastic plate 241 to be more tightly stuck in the groove 141. Continuous pressurization of the soluble plunger 2 transmits pressure from the first through hole 311 to the ninth casing 34. Then the third pin 341 is sheared off, and the ninth casing 34 moves down. During this process, the fracturing hole 122 is gradually opened, and the shearing C-ring 143 moves down to the shear groove 123. Then the shearing C-ring 143 springs open and is positioned in the corresponding shear groove 123. In Example 1, the sliding sleeve 1 has only two layers. In Example 2, the sliding sleeve 1 has three layers, which can effectively prevent the sliding sleeve 1 from opening prematurely during the cementing stage. After the fracturing hole 122 is opened, the fracturing hole 122 is connected to the inside of the sliding sleeve 1 through the second through hole 312, and multi-level segmented fracturing begins. After fracturing, dissolve the soluble plunger 2. The minimalist design of the soluble component effectively avoids secondary cross-linking problems during downhole dissolution.

[0048] The above embodiments are only used to illustrate the technical concept and features of the present invention, and are not intended to be unique or to limit the present invention. Those skilled in the art should understand that various changes or equivalent substitutions made to the present invention without departing from its scope are all within the protection scope of the present invention.

Claims

1. A dual-key intelligent switch large-diameter cementing sliding sleeve system, characterized in that, Includes multiple soluble plungers (2) and multiple sliding sleeves (1); The soluble plunger (2) includes a soluble ball (21), a ball seat (23), an elastic tube (24), and a front seat (25). The ball seat (23) has an opening at the top, and its inner wall is used to hold the soluble ball (21). The outer wall of the ball seat (23) is connected to the top of the elastic tube (24) by multiple first pins (231). The outer wall of the ball seat (23) is provided with multiple annular grooves, and a sealing ring is provided in the annular groove. The sealing ring is located above the elastic tube (24). The front seat (25) is connected to the bottom of the elastic tube (24). The outer wall of the elastic tube (24) is provided with two elastic rings and multiple strip grooves (242) that penetrate the elastic tube (24). The strip grooves (242) divide each elastic ring into multiple elastic pieces (241). The bottom of the elastic piece (241) has an acute angle structure, and the top has an obtuse angle structure. The inner wall of the sliding sleeve (1) is provided with two slots (141). The bottom of the slots (141) has an acute angle structure, which is used to hold the corresponding elastic plate (241) on the corresponding soluble plunger (2).

2. The dual-key intelligent switch large-diameter cementing sliding sleeve system according to claim 1, characterized in that, The soluble plunger (2) also includes a slip (22), which is fitted outside the ball seat (23). The outer wall of the ball seat (23) and the inner wall of the slip (22) are adapted to each other by a slope. The sealing ring of the outer wall of the ball seat (23) is located above the slip (22).

3. The dual-key intelligent switch large-diameter cementing sliding sleeve system according to claim 1, characterized in that, The sliding sleeve (1) includes an outer tube and an inner tube disposed therein. The outer tube includes a first sleeve (11), a second sleeve (12), and a third sleeve (13) connected in sequence. The inner tube includes a fourth sleeve (14) and a fifth sleeve (15) connected in sequence. The outer wall of the fourth sleeve (14) is close to the inner wall of the second sleeve (12). There is a gap (16) between the outer wall of the fifth sleeve (15) and the inner wall of the second sleeve (12). The outer wall of the fifth sleeve (15) is close to the inner wall of the third sleeve (13). The second sleeve (12) is fixedly connected to the fourth sleeve (14) by a plurality of second pins (121). The second sleeve (12) also has a plurality of fracturing holes (122) arranged in a circumferential array. The fracturing holes (122) are located between the first sleeve (11) and the second pins (121). Two slots (141) are provided on the inner wall of the fourth sleeve (14).

4. The dual-key intelligent switch large-diameter cementing sliding sleeve system according to claim 3, characterized in that, The inner diameter of the upper part of the third sleeve (13) is larger than the inner diameter of its lower part. When the second pin (121) is sheared and the inner tube moves down, the change in diameter of the inner diameter of the third sleeve (13) is used to support the fifth sleeve (15).

5. The dual-key intelligent switch large-diameter cementing sliding sleeve system according to claim 3, characterized in that, A sealing ring is provided between the inner walls of the first sleeve (11) and the second sleeve (12), a sealing ring is provided between the inner walls of the third sleeve (13) and the second sleeve (12), and three sealing rings are provided between the inner walls of the fourth sleeve (14) and the second sleeve (12).

6. The dual-key intelligent switch large-diameter cementing sliding sleeve system according to claim 3, characterized in that, The inner wall of the second sleeve (12) is provided with an annular shearing groove (123), which is located at the gap (16). The outer wall of the fourth sleeve (14) is provided with an annular groove, which contains two shearing C-rings (143). When the second pin (121) is sheared and the inner tube moves down, the shearing groove (123) is used to accommodate the shearing C-rings (143).

7. The dual-key intelligent switch large-diameter cementing sliding sleeve system according to claim 1, characterized in that, The sliding sleeve (1) includes a sixth sleeve (31), a seventh sleeve (32), an eighth sleeve (33), and a ninth sleeve (34). The outer wall of the sixth sleeve (31) is connected to the inner wall of the top end of the seventh sleeve (32). The inner wall of the bottom end of the seventh sleeve (32) is in close contact with the outer wall of the top end of the eighth sleeve (33). The inner wall of the top end of the eighth sleeve (33) is connected to the outer wall of the bottom end of the sixth sleeve (31). The ninth sleeve (34) is located in the gap (313) between the sixth sleeve (31) and the seventh sleeve (32), and the ninth sleeve (34) is connected by multiple third pins ( 341) Connect the outer wall of the sixth sleeve (31), and the seventh sleeve (32) has a circumferential array of multiple fracturing holes (122). The fracturing holes (122) are located below the third pin (341). The sixth sleeve (31) is provided with multiple first through holes (311) and multiple second through holes (312) in the circumferential direction. The first through holes (311) connect the gap (313), and the position of the first through holes (311) is higher than that of the ninth sleeve (34). The position of the second through holes (312) corresponds to the fracturing holes (122). Both slots (141) are provided on the inner wall of the eighth sleeve (33).

8. The dual-key intelligent switch large-diameter cementing sliding sleeve system according to claim 7, characterized in that, The outer wall of the ninth sleeve (34) is provided with two annular grooves, located above and below the fracturing hole (122) respectively. The inner wall of the ninth sleeve (34) is provided with two annular grooves, located above and below the fracturing hole (122) respectively. Each of these four annular grooves is provided with a sealing ring.

9. The dual-key intelligent switch large-diameter cementing sliding sleeve system according to claim 8, characterized in that, The outer wall of the ninth sleeve (34) is also provided with a third annular groove, which contains two shearing C-rings (143). The inner wall of the seventh sleeve (32) is provided with an annular shearing groove (123). When the third pin (341) is sheared and the ninth sleeve (34) moves down, the shearing groove (123) is used to accommodate the shearing C-rings (143).

10. The dual-key intelligent switch large-diameter cementing sliding sleeve system according to claim 1, characterized in that, The inner wall of the elastic tube (24) is provided with an inner ring, which is located within the range corresponding to the two slots (141). The top surface of the inner ring is set as a first inclined surface. The bottom end of the ball seat (23) extends to the inner ring. The outer wall of the bottom end of the ball seat (23) is set as a second inclined surface that matches the first inclined surface. The strip groove (242) divides the inner ring into multiple elastic blocks (243).

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