Full-bore well cementation fracturing sliding sleeve system

Abstract

The invention discloses a full-bore well cementation fracturing sliding sleeve system, which relates to the technical field of oil and gas well fracturing and is characterized in that a step is arranged on the inner wall of a ball seat and used for clamping a soluble ball, a body pipe is in threaded connection with the outer wall of the bottom end of the ball seat, and a pressing ring assembly, a rubber sleeve, the pressing ring assembly, a wedge-shaped body, a slip and an elastic pipe are sequentially arranged outside the body pipe in a sleeving manner; the wedge-shaped body is fixed to the body pipe through a plurality of first shear pins arrayed in the circumferential direction, the outer wall of the wedge-shaped body is matched with the inner wall of the slip through an inclined face, the elastic pipe is fixed to the body pipe through a plurality of second shear pins arrayed in the circumferential direction, the front base is in threaded connection to the bottom of the body pipe, a plurality of elastic pieces are arrayed on the outer wall of the elastic pipe in the circumferential direction, and the bottom ends of the elastic pieces are acute angles. Two sides of the elastic sheet are respectively provided with a strip-shaped groove; clamping grooves are formed in the inner walls of the sliding sleeves, the bottom ends of the clamping grooves are acute angles, the multiple sliding sleeves are assembled from top to bottom according to the sequence that the lengths of the clamping grooves are increased step by step, and the clamping grooves are used for clamping the elastic pieces of the corresponding soluble plungers. According to the scheme, the sealing performance and the pressure bearing capacity are improved.

Description

Technical Field

[0001] The invention relates to the technical field of oil and gas well fracturing, and in particular to a full-bore cementing fracturing sliding sleeve system. Background Art

[0002] In the fracturing operation of oil and gas wells, multi-stage fracturing is a commonly used technology to improve the recovery rate of oil and gas. The principle is as follows: a soluble plunger is put into the wellbore and stuck in the corresponding sliding sleeve to form a sealed area to isolate different fracturing sections so that fracturing operations can be carried out in this area; after the fracturing is completed, the soluble plunger dissolves under specific conditions (such as temperature, pressure or chemical reaction).

[0003] There are two keys to successful fracturing: one is sealing. If the structural design, material selection or installation of the sleeve and the soluble plunger are improper, the seal between the sleeve and the soluble plunger will not be tight enough, affecting the fracturing effect. The second is pressure bearing capacity. The soluble plunger is stuck in the sleeve and mainly relies on the pressure at the point where the soluble plunger is stuck. If the structural design of the sleeve and the soluble plunger is improper, it cannot withstand the stress under high-pressure environment, which will cause the soluble plunger to rupture or fail.

[0004] For example, CN114482957 B discloses a naked hole full-diameter infinite-stage segmented fracturing completion device and a fracturing completion method thereof. This solution only seals the opening tool and the sleeve through the second seal. After the opening tool is dropped into the wellbore, for a well section of 4000-6000 meters in length, the second seal will be worn out. After reaching the target layer, the second seal cannot perform the sealing function. This solution enables the opening tool to be stuck in the corresponding sleeve by clamping the opening slider in the opening groove. However, the cross-sectional shapes of the opening slider and the opening groove are both trapezoidal, and the pressure-bearing capacity is small.

[0005] In order to effectively carry out fracturing construction, improve the flexibility and accuracy of fracturing operations, and reduce operating costs and complexity, this solution redesigns the structure of the sleeve and the soluble plunger to enhance the sealing and pressure-bearing capacity. Summary of the invention

[0006] In order to solve the deficiencies of the prior art, the present invention provides a full-bore cementing fracturing sleeve system to improve the sealing performance and pressure bearing capacity.

[0007] In order to achieve the purpose of the present invention, the following scheme is proposed: A full-bore cementing fracturing sliding sleeve system, comprising a plurality of soluble plungers and a plurality of sliding sleeves; The soluble plunger includes a soluble ball, a rubber cylinder, two pressure ring assemblies, a wedge-shaped body, a slip, a ball seat, a main body tube, an elastic tube, and a front seat. The top of the ball seat is open, and its inner wall is provided with a step for clamping the soluble ball. The outer wall of the bottom end of the ball seat is threadedly connected to the main body tube. Starting from the ball seat, the pressure ring assembly, the rubber cylinder, the pressure ring assembly, the wedge-shaped body, the slip, and the elastic tube are sequentially sleeved outside the main body tube. The wedge-shaped body is fixed to the main body tube through a plurality of first shear pins in a circumferential array. The outer wall of the wedge-shaped body and the inner wall of the slip are adapted through an inclined surface. The elastic tube is fixed to the main body tube through a plurality of second shear pins in a circumferential array. The front seat is threadedly connected to the bottom of the main body tube. The outer wall of the elastic tube is provided with a plurality of elastic sheets in a circumferential array. The bottom end of the elastic sheet is an acute-angle structure, and the top end is an obtuse-angle structure. A strip groove penetrating the elastic tube is provided on each side of the elastic sheet. A slot is provided on the inner wall of the sleeve, and the bottom end of the slot is an acute angle structure. From top to bottom, multiple sleeves are assembled together in the order of increasing slot lengths. The slot is used to clamp the elastic sheet corresponding to the soluble plunger.

[0008] The beneficial effects of the present invention are: 1. By squeezing the rubber tube, the rubber of the rubber tube expands and fits tightly against the inner wall of the sleeve to achieve effective sealing.

[0009] 2. The pressure-bearing level of the soluble plunger is 70MPa. It bears pressure in the following two ways: first, it bears pressure through the elastic sheet. The bottom end of the elastic sheet can be inserted downward into the slot to improve the pressure-bearing capacity; second, the slips open and clamp the inner wall of the sleeve, which can also play a role in bearing pressure.

[0010] 3. The length of the slot of each sleeve is different. The sleeves are assembled in a specific order and placed into the wellbore in the order of increasing slot length from top to bottom. Then the corresponding soluble plungers are placed into the wellbore in turn to ensure that the soluble plungers are stuck in the sleeve at a specific position to improve accuracy.

[0011] 4. The diameter of the sliding sleeve can be maintained after fracturing is completed, which is convenient for subsequent well repair operations.

[0012] 5. No need for perforation and additional packer layers, the continuous one-trip fracturing operation not only ensures the continuity of the fracturing operation, but also shortens the operation time and saves costs.

[0013] 6. The sliding sleeve can effectively avoid casing deformation caused by weakening of the casing due to perforation.

[0014] 7. The sliding sleeve is opened and closed by a soluble plunger. When the sliding sleeve is opened and fracturing is carried out, only the soluble plunger remains in the wellbore, which can effectively reduce construction accidents.

[0015] 8. It avoids the problem of water coming out of the oil layer after conventional casing perforation. The closing tool can be lowered into the coiled tubing to close the sliding sleeve at the water outlet position, which is simple and convenient to operate.

[0016] 9. The use of the sliding sleeve greatly increases the integrity of the casing. The characteristic of the sliding sleeve that can be opened and closed multiple times can effectively avoid the conventional one-time mining method and reserve working space for later production layer processing.

[0017] 10. The elastic sheet soluble plunger is easy to operate and highly reliable.

[0018] 11. Even if the casing is slightly deformed, it will not affect the permeability of the soluble plunger and the subsequent fracturing construction.

[0019] 12. The soluble plunger can be directly placed without the assistance of other equipment, which greatly saves costs.

[0020] 13. Pure mechanical structure, without any electronic components. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 The external structure diagram of the sliding sleeve is shown; Figure 2 The external structure diagram of the soluble plunger is shown; Figure 3 A cross-sectional view of a soluble plunger is shown; Figure 4 The external structure diagram of the first casing is shown; Figure 5 The external structure diagram of the second casing is shown; Figure 6 The external structure diagram of the third casing is shown; Figure 7 The external structure diagram of the fourth casing is shown; Figure 8 shows a view of the interior of a fourth casing; Fig. 9 The external structure diagram of the fifth casing is shown; Fig.10 A cross-sectional view showing the soluble plunger being stuck in the sliding sleeve; Fig.11 for Fig.10 A partial enlarged view of the middle part; Fig.12 for Fig.10 A partial enlarged view of point B in the middle; Fig.13 for Fig.10 A partial enlarged view of point C in the middle; Fig.14 for Fig.10 A partial enlarged view of point D in the middle; Fig.15 for Fig.10 A partial enlarged view of point E in the middle; Fig.16 for Fig.10A partial enlarged view of point F in the middle. DETAILED DESCRIPTION

[0022] like Figure 1 , Fig.10 , Fig.14 As shown, this embodiment provides a full-bore cementing fracturing sleeve system, including multiple soluble plungers and multiple sleeves. The inner wall of each sleeve is provided with a groove 141, and the bottom end of the groove 141 is an acute-angle structure. From top to bottom, multiple sleeves are assembled together in the order of gradually increasing lengths of the grooves 141, and the soluble plungers are stuck in the corresponding sleeves.

[0023] Specifically, Figure 2 , Figure 3 , Figure 10-Figure 14 As shown, the soluble plunger includes a soluble ball 51, a rubber cylinder 52, two pressure ring assemblies 3, a wedge 53, a slip 54, a ball seat 55, a main body tube 56, an elastic tube 57, and a front seat 58. The top of the ball seat 55 is open, and the inner wall of the ball seat 55 is provided with a step for clamping the soluble ball 51. The outer wall of the bottom end of the ball seat 55 is threadedly connected to the top of the main body tube 56. Starting from the ball seat 55, the pressure ring assembly 3, the rubber cylinder 52, the pressure ring assembly 3, the wedge 53, the slip 54, and the elastic tube 57 are sequentially sleeved on the outside of the main body tube 56. The wedge 53 is fixed to the main body tube 56 by a plurality of first shear pins 21 in a circumferential array. The outer wall of the wedge 53 and the inner wall of the slip 54 Through the matching of the inclined surfaces, the outer wall of the top end of the elastic tube 57 is fixed to the main body tube 56 through a plurality of second shear pins 22 in a circumferential array, and the outer wall of the top end of the front seat 58 is threadedly connected to the bottom of the main body tube 56. The outer wall of the elastic tube 57 is arranged in a circumferential array with a plurality of elastic sheets 571. The outer wall of the elastic sheet 571 is arc-shaped, and the center of the arc is located on the central axis of the elastic tube 57. The bottom end of the elastic sheet 571 is an acute-angle structure, and the top end is an obtuse-angle structure. A strip groove 572 penetrating the elastic tube 57 is arranged on each side of the elastic sheet 571. The function of the strip groove 572 is to enable the elastic tube 57 to be elastically deformed, and the soluble plunger is clamped in the corresponding slot 141 of the sliding sleeve through the elastic sheet 571.

[0024] From the wellhead to the well bottom, the length of the slot 141 of the sliding sleeve increases step by step, so when the soluble plugs are put into the wellbore, the soluble plug with the longest elastic piece 571 is put in first, and then the soluble plugs with gradually decreasing elastic piece 571 lengths are put in successively.

[0025] The sealing principle is as follows: After the soluble plunger is clamped in the corresponding sliding sleeve, pressure is applied to the soluble plunger, and the elastic sheet 571 is tightly clamped into the clamping groove 141. The soluble ball 51, the ball seat 55, the main tube 56, the rubber tube 52, the two pressure ring assemblies 3, and the wedge body 53 move downward as a whole. The second shear pin 22 of the elastic tube 57 is sheared off by force, and the first shear pin 21 of the wedge body 53 is sheared off by force. In this process, the tip of the bottom of the wedge body 53 squeezes the slip 54, so that the slip 54 opens and clamps the inner wall of the sliding sleeve. The two pressure ring assemblies 3 squeeze the rubber tube 52, so that the rubber of the rubber tube 52 expands and fits tightly against the inner wall of the sliding sleeve to achieve sealing.

[0026] The pressure conditions are as follows: First, the pressure is borne by the elastic sheet 571, and the bottom end of the elastic sheet 571 is inserted downward into the slot 141, thereby improving the pressure bearing capacity; second, the slip 54 opens and clamps the inner wall of the sliding sleeve, which can also play a role in bearing pressure.

[0027] When the soluble plunger is put into the wellbore, the elastic sheet 571 is in a compressed state when entering the well. In order to ensure that the soluble plunger enters the well smoothly and reaches the sliding sleeve at a specific position, the present embodiment adopts the following measures: Figure 2 , Figure 3 , Fig.10 , Fig.14 As shown, the outer wall of the elastic tube 57 is also arrayed with a plurality of straightening pieces 573 along the circumferential direction. The number and position of the straightening pieces 573 correspond to the elastic pieces 571 one by one. The outer diameter of the straightening piece 573 is larger than the outer diameter of the elastic piece 571. The straightening piece 573 is located between the elastic piece 571 and the front seat 58. The bottom and top ends of the straightening piece 573 are both obtuse-angle structures. The bottom end of the strip groove 572 is located between the straightening piece 573 and the front seat 58. A circle of avoidance grooves 147 is provided on the inner wall of the sliding sleeve. When the soluble plunger is stuck in the corresponding slot 141, the straightening piece 573 is located in the avoidance groove 147.

[0028] Because the outer diameter of the straightening piece 573 is slightly larger than the outer diameter of the elastic piece 571, when the soluble plunger enters the small inner diameter space from the large inner diameter of the sliding sleeve, the straightening piece 573 will be compressed, and the straightening piece 573 will drive the elastic piece 571 to be compressed as a whole, ensuring that the entire soluble plunger will not get stuck when entering the small inner diameter, and further ensuring that it will only get stuck in the slot 141 of a specific length.

[0029] The specific structure of the pressure ring assembly 3 is as follows: Figure 2 , Figure 3 , Fig.12 , Fig.13As shown, the area between the ball seat 55, the wedge-shaped body 53 and the outer wall of the main body tube 56 constitutes a groove, and the two pressure ring assemblies 3 are symmetrically arranged in the groove. The pressure ring assembly 3 includes a first ring 31, a second ring 32, a third ring 33 and a fourth ring 34 in sequence. For the upper pressure ring assembly 3, the first ring 31 is adapted to the ball seat 55 through an inclined surface, the first ring 31 is adapted to the second ring 32 through a step, the second ring 32 is adapted to the third ring 33 through an inclined surface, and the fourth ring 34 is adapted to the rubber tube 52 through a step. For the lower pressure ring assembly 3, the first ring 31 is adapted to the wedge-shaped body 53 through an inclined surface, and the cross-sectional shape of the fourth ring 34 can be selected to be rectangular or L-shaped.

[0030] like Fig.12 As shown, a circle of trapezoidal grooves is provided on the inner wall of the rubber sleeve 52 , and a sealing sleeve 521 and a sealing ring are provided in the trapezoidal groove, and the sealing ring is located on the inner side of the sealing sleeve 521 .

[0031] The specific structure of slip 54 is as follows: Figure 2 As shown, the outer wall of the slip 54 is provided with two circles of inlaid columns 541, and corresponding positions at the upper and lower ends of the slip 54 are provided with cutouts 542. The function of the cutouts 542 is to ensure that when the tip of the bottom of the wedge-shaped body 53 squeezes the slip 54, the slip 54 can be smoothly opened and clamped to the inner wall of the sliding sleeve.

[0032] The soluble plunger provided in this embodiment has the following performance advantages: ①Adapt to different temperature ranges of 38℃~178℃ (100F-350F); ② A variety of material combination designs can be provided to meet the requirements of different blocks; ③ The pressure level is 70MPa (10000PSI), with integrated anti-premature setting design, which can be set in the sliding sleeve at a specific position; ④100% metal soluble material, completely dissolved within 5 days (the dissolution time can be adjusted according to site needs); ⑤ Fine treatment of metal surface, surface coating treatment, acid-resistant, water-soluble, anti-corrosion surface spraying to adapt to the construction wells of acid injection immersion; ⑥Applicable to all current casing steel grades (P110 / 125 / 140, etc.); ⑦ The maximum inner diameter design is conducive to flowback after fracturing without affecting production.

[0033] The specific structure of the sliding sleeve is as follows: Figure 1 , Figure 14-16As shown, the sliding sleeve includes an outer tube and an inner tube arranged therein, the outer tube includes a first sleeve 11, a second sleeve 12, and a third sleeve 13 which are threadedly connected in sequence, the inner tube includes a fourth sleeve 14 and a fifth sleeve 15 which are threadedly connected, the outer wall of the fourth sleeve 14 is in close contact with 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 in close contact with the inner wall of the third sleeve 13, the second sleeve 12 is fixedly connected to the fourth sleeve 14 through a circumferentially arrayed plurality of third shear pins 121, the second sleeve 12 also has a circumferentially arrayed plurality of fracturing holes 122, the third shear pins 121 are located between the first sleeve 11 and the fracturing holes 122, the card slot 141 and the avoidance slot 147 are both arranged on the inner wall of the fourth sleeve 14.

[0034] About the specific connection method of the outer tube and the inner tube: like Figure 4 , Figure 5 , Fig.11 As shown, the top of the first sleeve 11 is provided with an internal thread, the bottom of the first sleeve 11 is provided with an external thread and a smooth section, the external thread of the first sleeve 11 is connected to the second sleeve 12, the smooth section of the first sleeve 11 is close to the inner wall of the second sleeve 12, and the end surface of the top of the fourth sleeve 14 is in contact with the end surface of the smooth section, as shown in FIG. Figure 7 , Fig. 9 , Fig.15 As shown, the inner wall of the bottom end of the fourth sleeve 14 is threadedly connected to the fifth sleeve 15, as shown in FIG. Figure 5 , Figure 6 , Fig.16 As shown, the top of the third sleeve 13 is provided with an external thread and a smooth section, the bottom of the third sleeve 13 is provided with an internal thread, the external thread of the third sleeve 13 is connected to the second sleeve 12, and the smooth section of the third sleeve 13 is in close contact with the inner wall of the second sleeve 12.

[0035] like Figure 7 , Figure 11-Figure 16 As shown, the outer wall of the smooth section of the first sleeve 11 is provided with a first annular groove 111, and from top to bottom, the outer wall of the fourth sleeve 14 is provided with a second annular groove 142, a third annular groove 143, and a fourth annular groove 144 in sequence, and the outer wall of the smooth section of the third sleeve 13 is provided with a sixth annular groove 131, and the third shear pin 121 is installed in the third annular groove 143. Except for the third annular groove 143, the first annular groove 111, the second annular groove 142, the fourth annular groove 144, and the sixth annular groove 131 are all provided with sealing rings.

[0036] like Fig.15As shown, the inner wall of the second sleeve 12 is provided with two annular shear grooves 123, and the shear grooves 123 are located at the gap 16. The outer wall of the fourth sleeve 14 is provided with a fifth annular groove 145, and two shear C rings 146 are arranged in the fifth annular groove 145. When the inner tube loses the restriction of the third shear pin 121 and moves downward, the shear groove 123 is used to accommodate the corresponding shear C rings 146. It is explained here that when the inner tube and the soluble plunger move downward together, the gap 16 is used to avoid the fourth sleeve 14.

[0037] The shear C-ring 146 has two functions: ① when the inner tube moves downward, the shear C-ring 146 will move with the inner tube into the shear groove 123 of the main body; ② the shear C-ring 146 has a certain shear value. When the sliding sleeve needs to be closed again, a shear value higher than the shear C-ring 146 can be applied to the inner tube.

[0038] Here’s how to use it: Assemble the outer tube and the inner tube together to form a sliding sleeve, and assemble the plurality of sliding sleeves in sequence according to a specific order; A plurality of sliding sleeves are lowered into the oil and gas layer in the well, wherein the length of the slot 141 of each sliding sleeve is different, and the length of the slot 141 increases step by step from top to bottom; After cementing, the soluble plungers are lowered in a specific order, and the soluble plungers are stuck in the corresponding sliding sleeves; The soluble plunger is pressurized, and the elastic sheet 571 is tightly inserted into the card slot 141. The soluble ball 51, the ball seat 55, the main body tube 56, the rubber tube 52, the two pressure ring components 3, and the wedge body 53 move downward as a whole. The second shear pin 22 of the elastic tube 57 is sheared off by force, and the first shear pin 21 of the wedge body 53 is sheared off by force. In this process, the tip of the bottom of the wedge body 53 squeezes the slip 54, so that the slip 54 opens and clamps the inner wall of the sliding sleeve. The two pressure ring components 3 squeeze the rubber tube 52, so that the rubber of the rubber tube 52 expands and fits tightly to the inner wall of the sliding sleeve to achieve sealing; the third shear pin 121 is sheared off by force, and the inner tube loses the restriction of the third shear pin 121. The inner tube and the soluble plunger move downward together. After reaching a specific position, the shear C ring 146 pops open and is positioned in the corresponding shear groove 123. In this process, the fracturing hole 122 is gradually opened; Start multi-layer staged fracturing; The soluble plunger is made of soluble metal material, such as magnesium-aluminum alloy. After fracturing is completed, the soluble plunger is dissolved to achieve full bore.

[0039] More specifically, since cement is placed during the cementing stage, in order to prevent the cement from being retained and solidified in the sleeve, which would result in the sleeve being unable to be opened, the present embodiment adopts the following measures: Figure 8 As shown, The inner wall of the fourth sleeve 14 is provided with a plurality of guide grooves 148 in a circumferential array, and the upper and lower ends of the guide grooves 148 are respectively connected to the card groove 141 and the avoidance groove 147. After the cement is injected, the cement slurry can be washed clean through the guide grooves 148 by mud or plugging liquid, so that the cement is not easily retained in the sliding sleeve.

[0040] In summary, this embodiment achieves precise control of multi-layer fracturing of oil and gas wells by adjusting the length of the elastic sheet 721 to clamp the soluble plunger in the sliding sleeve at a specific position. When the size of the soluble plunger meets the passing condition, the soluble plunger will pass through the sliding sleeve smoothly. When the size of the soluble plunger meets the sealing condition, the soluble plunger will be sealed at the sliding sleeve. When the soluble plunger is seated in the sliding sleeve, the displacement is increased, and the soluble plunger is sealed with a high displacement. The starting shear force of the soluble plunger sealing is adjustable (1-3 tons), thereby achieving layered fracturing of oil and gas wells. This design not only improves the flexibility and accuracy of fracturing operations, but also reduces operating costs and complexity.

[0041] The above embodiments are only used to illustrate the technical ideas and features of the present invention, and are not intended to be the only or limit the present invention. It should be understood by those skilled in the art that various changes or equivalent substitutions made to the present invention without departing from the scope of the present invention all fall within the scope of protection of the present invention.

Claims

1. A full-bore cementing fracturing sliding sleeve system, characterized in that: It includes a plurality of soluble plungers and a plurality of sliding sleeves; The soluble plunger comprises a soluble ball (51), a rubber cylinder (52), two pressure ring assemblies (3), a wedge-shaped body (53), a slip (54), a ball seat (55), a main body tube (56), an elastic tube (57), and a front seat (58). The ball seat (55) is provided with an opening at the top, and a step is provided on its inner wall for clamping the soluble ball (51). The outer wall of the bottom end of the ball seat (55) is threadedly connected to the main body tube (56). Starting from the ball seat (55), the pressure ring assembly (3), the rubber cylinder (52), the pressure ring assembly (3), the wedge-shaped body (53), the slip (54), and the elastic tube (57) are sequentially sleeved outside the main body tube (56). The wedge-shaped body (53) is fixed to the main body tube (56) via a plurality of first shear pins (21) arranged in a circumferential array; the outer wall of the wedge-shaped body (53) is matched with the inner wall of the slip (54) via an inclined surface; the elastic tube (57) is fixed to the main body tube (56) via a plurality of second shear pins (22) arranged in a circumferential array; the front seat (58) is threadedly connected to the bottom of the main body tube (56); the outer wall of the elastic tube (57) is provided with a plurality of elastic sheets (571) arranged in a circumferential array; the bottom end of the elastic sheet (571) is an acute angle structure and the top end is an obtuse angle structure; and a strip groove (572) penetrating the elastic tube (57) is provided on each side of the elastic sheet (571); A clamping groove (141) is provided on the inner wall of the sliding sleeve. The bottom end of the clamping groove (141) is an acute angle structure. From top to bottom, a plurality of sliding sleeves are assembled together in the order of increasing lengths of the clamping groove (141). The clamping groove (141) is used to clamp the elastic sheet (571) corresponding to the soluble plunger.

2. The full-bore cementing fracturing sliding sleeve system according to claim 1, characterized in that: The sliding sleeve comprises an outer tube and an inner tube arranged therein, the outer tube comprises a first sleeve (11), a second sleeve (12), and a third sleeve (13) which are threadedly connected in sequence, the inner tube comprises a fourth sleeve (14) and a fifth sleeve (15) which are threadedly connected, the outer wall of the fourth sleeve (14) is in close contact with the inner wall of the second sleeve (12), a gap (16) is provided 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 in close contact with the inner wall of the third sleeve (13), the second sleeve (12) is fixedly connected to the fourth sleeve (14) by a plurality of third shear pins (121) arranged in a circumferential array, the second sleeve (12) also has a plurality of fracturing holes (122) arranged in a circumferential array, the third shear pins (121) are located between the first sleeve (11) and the fracturing holes (122), and a clamping groove (141) is provided on the inner wall of the fourth sleeve (14).

3. The full-bore cementing fracturing sliding sleeve system according to claim 2, characterized in that: The first sleeve (11) has an internal thread at the top and an external thread and a smooth section at the bottom. The external thread of the first sleeve (11) is connected to the second sleeve (12). The smooth section of the first sleeve (11) is in close contact with the inner wall of the second sleeve (12). The end surface of the top of the fourth sleeve (14) is in contact with the end surface of the smooth section. The inner wall of the bottom of the fourth sleeve (14) is threadedly connected to the fifth sleeve (15). The third sleeve (13) has an external thread and a smooth section at the top and an internal thread at the bottom. The external thread of the third sleeve (13) is connected to the second sleeve (12). The smooth section of the third sleeve (13) is in close contact with the inner wall of the second sleeve (12).

4. The full-bore cementing fracturing sliding sleeve system according to claim 3, characterized in that: The smooth section outer wall of the first sleeve (11) is provided with a first annular groove (111), and the outer wall of the fourth sleeve (14) is provided with a second annular groove (142), a third annular groove (143), and a fourth annular groove (144) in order from top to bottom. The smooth section outer wall of the third sleeve (13) is provided with a sixth annular groove (131), and the third shear pin (121) is installed in the third annular groove (143). Except for the third annular groove (143), sealing rings are provided in the remaining annular grooves.

5. The full-bore cementing fracturing sliding sleeve system according to claim 2, characterized in that: The inner wall of the second sleeve (12) is provided with two annular shear grooves (123), the outer wall of the fourth sleeve (14) is provided with a fifth annular groove (145), and two shear C rings (146) are arranged in the fifth annular groove (145). When the third shear pin (121) is sheared off by force and the inner tube moves downward, the shear grooves (123) are used to accommodate the corresponding shear C rings (146).

6. The full-bore cementing fracturing sliding sleeve system according to claim 1, characterized in that: The outer wall of the elastic tube (57) is also provided with a plurality of straightening plates (573) arranged in an array along the circumferential direction. The number and position of the straightening plates (573) and the elastic plates (571) are in one-to-one correspondence. The straightening plates (573) are located between the elastic plates (571) and the front seat (58). The bottom and top ends of the straightening plates (573) are both obtuse-angled structures. The bottom end of the strip groove (572) is located between the straightening plates (573) and the front seat (58). The inner wall of the fourth sleeve (14) is provided with a circle of avoidance grooves (147). When the soluble plunger is stuck in the corresponding clamping groove (141), the straightening plates (573) are located in the avoidance grooves (147). The outer diameter of the straightening plates (573) is greater than the outer diameter of the elastic plates (571).

7. The full-bore cementing fracturing sliding sleeve system according to claim 6, characterized in that: The inner wall of the fourth sleeve (14) is provided with a plurality of guide grooves (148) in a circumferential array, and both ends of the guide grooves (148) are connected to the clamping groove (141) and the avoidance groove (147).

8. The full-bore cementing fracturing sliding sleeve system according to claim 1, characterized in that: The area between the ball seat (55), the wedge-shaped body (53) and the outer wall of the main body tube (56) forms a groove, and two pressure ring assemblies (3) are symmetrically arranged in the groove. The pressure ring assemblies (3) sequentially include a first ring (31), a second ring (32), a third ring (33) and a fourth ring (34). For the upper pressure ring assembly (3), the first ring (31) is matched with the ball seat (55) through an inclined surface, the first ring (31) is matched with the second ring (32) through a step, the second ring (32) is matched with the third ring (33) through an inclined surface, and the fourth ring (34) is matched with the rubber cylinder (52) through a step.

9. The full-bore cementing fracturing sliding sleeve system according to claim 1, characterized in that: The inner wall of the rubber cylinder (52) is provided with a circle of trapezoidal grooves, a sealing sleeve (521) and a sealing ring are provided in the trapezoidal groove, and the sealing ring is located on the inner side of the sealing sleeve (521).

10. The full-bore cementing fracturing sliding sleeve system according to claim 1, characterized in that: The outer wall of the slip (54) is provided with two circles of inlaid columns (541), and corresponding positions at both ends of the slip (54) are provided with cutouts (542).

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