Fracturing packer in small casing pipe

Abstract

The utility model relates to the technical field of packers, and discloses a fracturing packer in a small casing pipe, which comprises an extension pipe, a sand blower, a central pipe and a hydraulic cylinder which are arranged from top to bottom, a sealing rubber sleeve and slips are sleeved outside the central pipe, and the slips are arranged between the central pipe and the sealing rubber sleeve and between the sealing rubber sleeve and the hydraulic cylinder; the sand blaster comprises a sand blaster body and a sand blasting sliding sleeve arranged in the sand blaster body in a sleeved mode, the sand blaster body, the slip, the sealing rubber barrel and the hydraulic cylinder can be dissolved, a first locking ring groove used for installing the locking ring is formed in the peripheral face of the sand blasting sliding sleeve, a second locking ring groove used for installing the locking ring is formed in the upper portion of the center pipe, and a pressure transmitting through hole is formed in the lower portion of the center pipe. The hydraulic cylinder comprises an outer cylinder body, a mandrel and a lower connector arranged between the outer cylinder body and the mandrel in a sleeved mode, the mandrel is connected with the lower end of the center pipe, the outer cylinder body is connected with the lower connector, and the lower end of the lower connector is sleeved with a ball seat. The separate layer fracturing in the small casing pipe is realized, and the problem of unblocking of the packer in the small casing pipe is avoided.

Description

Technical Field

[0001] The utility model relates to the technical field of packers, and more specifically, to a fracturing packer in a small casing. Background Art

[0002] After the oilfield development enters the middle and late stages, the original formation energy decreases, displacement becomes difficult, and the recovery rate gradually decreases. Compared with drilling new wells, it is more economical and effective to replace the recovery point or pay zone by sidetracking and drilling the bottom hole based on the original wellbore.

[0003] Most of the original production casings of domestic oil wells are 5.5 inches in size. After sidetracking or deepening, 4-inch or smaller casings are suspended. Limited by the inner diameter of the casing, the current fracturing transformation of the pay zone is mostly limited to single-layer construction, and the difficulty of multi-layer fracturing transformation is very high.

[0004] In conventional casings, a double-packer fracturing string can be formed by combining an upper-stage K344 packer + a throttling sandblaster + a lower-stage K344 packer. Although the small casing can theoretically complete two-layer fracturing, a cemented carbide sleeve needs to be installed inside the throttling sandblaster to prevent the sand-carrying fluid from damaging the sandblasting port, which makes the size of the throttling sandblaster too large, resulting in too small an annulus when the sand-carrying fluid flows out of the orifice of the throttling sandblaster and enters the formation, and the risk during fracturing is too high; while using a conventional sandblaster, the lower-stage K344 packer needs to be replaced with a releasable packer such as Y221 or Y341, and it is difficult to solve the problem of releasing the packer in the small casing.

[0005] In summary, how to provide a fracturing packer for multi-layer fracturing in a small casing is an urgent problem to be solved by those skilled in the art at present. Content of the Utility Model

[0006] In view of this, the purpose of the utility model is to provide a fracturing packer in a small casing, and the sandblaster body, slips, sealing rubber cylinder and hydraulic cylinder can all be dissolved, which not only realizes multi-layer fracturing in the small casing, but also avoids the problem of releasing the packer in the small casing.

[0007] In order to achieve the above purpose, the utility model provides the following technical solutions:

[0008] A fracturing packer in a small casing includes an extension pipe, a sandblaster, a central pipe and a hydraulic cylinder arranged from top to bottom. A sealing rubber cylinder and slips are sleeved outside the central pipe, and the slips are arranged between the central pipe and the sealing rubber cylinder, and between the sealing rubber cylinder and the hydraulic cylinder;

[0009] The sandblaster includes a sandblaster body and a sandblasting sliding sleeve sleeved inside the sandblaster body. The sandblaster body, the slip, the seal rubber cylinder, and the hydraulic cylinder are all dissolvable. A first locking ring groove for installing a locking ring is provided on the outer peripheral surface of the sandblasting sliding sleeve. A second locking ring groove for installing the locking ring is provided on the upper part of the central pipe. A pressure transmission through hole is provided on the lower part of the central pipe.

[0010] The hydraulic cylinder includes an outer cylinder body, a core shaft, and a lower joint sleeved between the outer cylinder body and the core shaft. The core shaft is connected to the lower end of the central pipe. The outer cylinder body is connected to the lower joint. A ball seat is sleeved on the lower end of the lower joint.

[0011] Preferably, the sandblasting sliding sleeve can slide relative to the inner peripheral surface of the sandblaster body, and the sandblasting sliding sleeve is connected to the sandblaster body through a shear pin.

[0012] Preferably, a wear-resistant part is provided on the upper part of the central pipe. The wear-resistant part is sleeved on the inner peripheral surface of the central pipe and is clamped in a limiting groove formed by the sandblaster body and the sandblasting sliding sleeve.

[0013] Preferably, at least one second sealing ring is provided between the wear-resistant part and the sandblasting sliding sleeve. The second sealing ring is clamped in a second sealing groove on the outer peripheral surface of the sandblasting sliding sleeve.

[0014] Preferably, the slip includes a plurality of slip pieces uniformly arranged around the central pipe. The structures and sizes of the slips at both ends of the seal rubber cylinder are the same.

[0015] Preferably, a limiting step for abutting against the central pipe is provided at the upper end of the core shaft. The core shaft is threadedly connected to the lower end of the central pipe.

[0016] Preferably, the outer cylinder body and the lower joint are connected through a shear pin. The lower joint and the ball seat are connected through the shear pin.

[0017] Preferably, at least one first sealing ring is provided between the sandblaster body and the sandblasting sliding sleeve. The first sealing ring is clamped in a first sealing groove on the outer peripheral surface of the sandblasting sliding sleeve.

[0018] Preferably, at least one third sealing ring is provided between the outer cylinder body and the central pipe. The third sealing ring is clamped in a third sealing groove on the inner peripheral surface of the outer cylinder body.

[0019] Preferably, at least one fourth sealing ring is provided between the outer cylinder body and the core shaft. The fourth sealing ring is arranged in a fourth sealing groove on the outer peripheral surface of the core shaft;

[0020] At least one fifth sealing ring is provided between the lower sub and the mandrel, and the fifth sealing ring is clamped in a fifth sealing groove on the inner peripheral surface of the lower sub.

[0021] During use, the small casing inner fracturing packer can form a "single packer fracturing two layers" string by itself, or cooperate with a general packer to form a "double packer fracturing two layers" string; when the string reaches the predetermined position, a setting ball is dropped into the wellhead, and the setting ball falls to the ball seat of the lower sub at the bottom end of the packer. Then, pressure is applied by a pump truck, and the pressure enters the hydraulic cylinder through the pressure transmission through hole of the central pipe. When the pressure received by the outer cylinder body of the hydraulic cylinder reaches a certain value, the connection between the outer cylinder body and the lower sub is sheared and damaged, causing the outer cylinder body to move upward, squeeze the slips and the sealing rubber barrel. The slips are pressed out to complete setting. Subsequently, continue to apply pressure by the pump truck to increase the pressure inside the packer, and use the pressure to knock the setting ball and the ball seat to the bottom of the well.

[0022] When fracturing the lower pay zone, the fracturing fluid flows through the extension pipe, the sandblasting sleeve and the central pipe in sequence, and then enters the wellbore and the pay zone. After the construction of the lower pay zone is completed, a fracturing ball is dropped into the wellhead. When the fracturing ball reaches the position of the sandblaster, the pump truck is used to apply pressure to push the fracturing ball and the sandblasting sleeve downward until the sandblasting sleeve is locked with the central pipe through the locking ring, so that the sandblasting port of the sandblaster body is exposed to communicate with the upper pay zone for fracturing.

[0023] After all the construction is completed and entering the stage of flowing back and production testing, as the formation fluid flows to the ground, the sandblasting port of the sandblaster gradually dissolves until it breaks off. Then, the extension pipe can be taken out through the upper pipe string, and the remaining sandblaster body, slips, sealing rubber barrel and hydraulic cylinder are gradually dissolved, and the central pipe and the sandblasting sleeve fall to the bottom of the well due to the loss of support.

[0024] Therefore, the small casing inner fracturing packer provided by the present utility model realizes layered fracturing in the small casing. And since the sandblaster body, slips, sealing rubber barrel and hydraulic cylinder can all be dissolved, the problem of releasing the packer in the small casing is avoided. The construction cost is low, the safety is high, and the operation procedure is simple, and it can be directly put into production after pressure preparation. Description of the Drawings

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present utility model or the prior art, the following will briefly introduce the drawings required to be used in the description of the embodiments or the prior art. Obviously, the following drawings are only the embodiments of the present utility model. For those of ordinary skill in the art, other drawings can be obtained according to the provided drawings without creative efforts.

[0026] Figure 1 It is a half-sectional schematic view of a specific embodiment of the small casing inner fracturing packer provided by the present utility model;

[0027] Figure 2 for Figure 1 A partial enlarged view of

[0028] Figure 3 is a half-section schematic diagram of the central tube;

[0029] Figure 4 This is a half-section schematic diagram of the hydraulic cylinder.

[0030] Figures 1 - 4 middle:

[0031] 10-frac ball; 20-seat sealing ball; 1-extension tube; 2-sandblaster body; 3-sandblasting sleeve; 31-first sealing groove; 32-second sealing groove; 4-center tube; 41-wear-resistant part; 42-second locking ring groove; 43-pressure transmission hole; 5-slip; 6-sealing rubber cylinder; 7-hydraulic cylinder; 71-outer cylinder body; 711-third sealing groove; 72-core shaft; 721-fourth sealing groove; 73-lower joint; 731-fifth sealing groove; 74-ball seat; 8-shear pin. DETAILED DESCRIPTION

[0032] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0033] The core of the utility model is to provide a fracturing packer in a small casing. The sandblaster body, slips, sealing rubber tube and hydraulic cylinder are all soluble, which not only realizes the layered fracturing in the small casing, but also avoids the problem of unsealing the packer in the small casing.

[0034] The utility model provides a small casing internal fracturing packer, comprising an extension pipe 1, a sandblaster, a center pipe 4 and a hydraulic cylinder 7 arranged from top to bottom, the center pipe 4 is provided with a sealing rubber tube 6 and slips 5 on its outer sleeve, and the slips 5 are arranged between the center pipe 4 and the sealing rubber tube 6, and between the sealing rubber tube 6 and the hydraulic cylinder 7;

[0035] The sandblaster comprises a sandblaster body 2 and a sandblasting sleeve 3 sleeved in the sandblaster body 2. The sandblaster body 2, slips 5, sealing rubber tube 6 and hydraulic cylinder 7 are all soluble. The outer peripheral surface of the sandblasting sleeve 3 is provided with a first locking ring groove for installing a locking ring, the upper part of the center tube 4 is provided with a second locking ring groove 42 for installing a locking ring, and the lower part of the center tube 4 is provided with a pressure transmission through hole 43;

[0036] The hydraulic cylinder 7 includes an outer cylinder body 71, a mandrel 72, and a lower joint 73 sleeved between the outer cylinder body 71 and the mandrel 72. The mandrel 72 is connected to the lower end of the central tube 4, the outer cylinder body 71 is connected to the lower joint 73, and a ball seat 74 is sleeved inside the lower joint 73.

[0037] Among them, the extension pipe 1 is of a hollow pipe structure. The upper end of the extension pipe 1 is used to connect with the oil pipe, and the lower end of the extension pipe 1 is used to connect with the sandblaster body 2 of the sandblaster.

[0038] To facilitate the assembly of the packer, it is preferably set that the extension pipe 1 is connected to the oil pipe through an oil pipe thread, and the extension pipe 1 is connected to the sandblaster body 2 through a straight thread, so that the sandblaster body 2 has a smaller outer diameter, in order to reduce the annular friction during the process of the sand-carrying fluid entering the formation from the sandblasting port through the annulus.

[0039] The outer diameter of the extension pipe 1 is smaller than the outer diameter of the sandblaster body 2. The length of the extension pipe 1 is determined according to the thickness of the producing formation, while the material and structure of the extension pipe 1 can be determined according to the geological characteristics of the producing formation.

[0040] The sandblaster includes a sandblaster body 2 and a sandblasting sliding sleeve 3. The upper end of the sandblaster body 2 is threadedly connected to the lower end of the extension pipe 1, which is convenient for assembly and has strong sealing performance at the connection. The lower end of the sandblaster body 2 is provided with a through sandblasting port. When the sandblasting sliding sleeve 3 descends to lock with the central tube 4, the sandblasting port is communicated with the inner hole of the sandblaster, so as to communicate with the producing formation to implement fracturing.

[0041] The sandblasting sliding sleeve 3 is slidably sleeved inside the sandblaster body 2. The sandblasting sliding sleeve 3 can be connected to the sandblaster body 2 through a shear pin 8 or through a short-thread pair, so that the sandblasting sliding sleeve 3 can be separated from the sandblaster body 2 under pressure and can slide downward along the inner circumference of the sandblaster body 2.

[0042] Preferably, at least one first sealing ring is provided between the sandblaster body 2 and the sandblasting sliding sleeve 3, and the first sealing ring is clamped in the first sealing groove 31 on the outer peripheral surface of the sandblasting sliding sleeve 3.

[0043] To fix the relative positions of the sandblasting sliding sleeve 3 and the central tube 4, a first lock ring groove is provided on the outer peripheral surface of the sandblasting sliding sleeve 3, and a second lock ring groove 42 is provided on the inner peripheral surface of the central tube 4. A lock ring is provided in the first lock ring groove. When the sandblasting sliding sleeve 3 descends until the first lock ring groove and the second lock ring groove 42 are aligned, the lock ring is snapped into the second lock ring groove 42 to restrict the axial movement of the sandblasting sliding sleeve 3 by using the second lock ring groove 42.

[0044] The specific materials, structures, shapes, sizes, etc. of the lock ring, the first lock ring groove, and the second lock ring groove 42 are determined with reference to the prior art according to factors such as the design dimensions and design working conditions of the internal packer in actual production, and will not be elaborated here.

[0045] The central pipe 4 is connected to the lower end of the sandblasting tool body 2. Preferably, a positioning step surface is provided in the middle of the sandblasting tool body 2, and the upper end of the central pipe 4 abuts against the positioning step surface of the sandblasting tool body 2. The middle part of the central pipe 4 is threadedly connected to the lower end of the sandblasting tool body 2. The connection structure is simple, the assembly accuracy is high, and the connection stability is strong;

[0046] The lower end of the central pipe 4 is connected to the hydraulic cylinder 7. A pressure transmission through hole 43 is provided in the lower part of the central pipe 4. The pressure transmission through hole 43 is used to transmit pressure and drive the outer cylinder body 71 of the hydraulic cylinder 7 to move upward under the action of pressure, so as to squeeze the slips 5 and the sealing rubber cylinder 6.

[0047] A sealing rubber cylinder 6 is provided between the sandblasting tool body 2 and the outer cylinder body 71. The sealing rubber cylinder 6 abuts against the sandblasting tool body 2 and the outer cylinder body 71 through the slips 5 at the upper and lower ends. Both the slips 5 and the sealing rubber cylinder 6 are sleeved outside the central pipe 4.

[0048] Both the slips 5 and the sealing rubber cylinder 6 are made of dissolvable materials so that the slips 5 and the sealing rubber cylinder 6 can be dissolved after the fracturing is completed. The specific materials of the slips 5 and the sealing rubber cylinder 6 are determined according to the geological characteristics of the production formation;

[0049] For example, it is usually set that the sandblasting tool body 2, the slips 5 and the hydraulic cylinder 7 are made of soluble magnesium alloy. The soluble magnesium alloy improves the physical properties of the alloy by adding certain proportions of metal elements such as aluminum, zinc, and iron. The sealing rubber cylinder 6 is made of soluble rubber material. The soluble rubber can be specifically prepared from nitrile rubber, antioxidant, activator, and reinforcing agent, etc.

[0050] The specific structures, shapes, and sizes of the slips 5 and the sealing rubber cylinder 6 are determined with reference to the prior art according to actual production needs. For example, it can be set that the slips 5 include a plurality of slip pieces evenly arranged around the central pipe 4, and the structures and sizes of the slips 5 at both ends of the sealing rubber cylinder 6 are the same to reduce the number of fittings and facilitate assembly.

[0051] The hydraulic cylinder 7 is provided with an outer cylinder body 71, a mandrel 72, and a lower joint 73 from top to bottom. Please refer to Figure 1 , both the outer cylinder body 71 and the mandrel 72 are sleeved outside the central pipe 4, and the pressure transmission through hole 43 in the lower part of the central pipe 4 is arranged facing the axial gap between the outer cylinder body 71 and the mandrel 72. Therefore, when pumping fluid into the packer from the surface by a pump truck, the outer cylinder body 71 moves upward under the action of the upward pressure;

[0052] The mandrel 72 is connected to the lower end of the central tube 4. Therefore, when the outer cylinder body 71 moves upward, the mandrel 72 is stationary relative to the central tube 4. The two can be connected by an interference fit or by a threaded connection. Preferably, a limiting step for abutting against the central tube 4 is provided at the upper end of the mandrel 72, and the mandrel 72 is threadedly connected to the lower end of the central tube 4, which not only ensures the connection stability between the mandrel 72 and the central tube 4 but also guarantees the coaxiality of the mandrel 72 and the central tube 4.

[0053] The lower joint 73 is sleeved between the outer cylinder body 71 and the mandrel 72. In order to effectively axially position the lower joint 73, an outer positioning step surface for abutting against the lower end surface of the outer cylinder body 71 is provided on the outer peripheral surface of the lower joint 73, and an inner positioning step surface for abutting against the lower end surface of the mandrel 72 is provided on the inner peripheral surface of the lower joint 73.

[0054] A ball seat 74 for receiving the setting ball 20 is provided inside the lower joint 73. The structure, shape, and size of the ball seat 74 are connected according to the structure, shape, and size of the setting ball 20 in actual production.

[0055] The outer cylinder body 71 and the central tube 4, as well as the lower joint 73 and the ball seat 74, can be connected either by shear pins 8 or by a short-threaded pair, so that the above connections can be quickly disconnected under pressure.

[0056] In order to prevent the pressure received by the outer cylinder body 71 from being dispersed by the gap between the central tube 4 and the outer cylinder body 71, the sealing performance between the central tube 4 and the outer cylinder body 71 needs to be ensured. Preferably, at least one third sealing ring is provided between the outer cylinder body 71 and the central tube 4, and the third sealing ring is clamped in the third sealing groove 711 on the inner peripheral surface of the outer cylinder body 71.

[0057] In order to prevent the pressure received by the outer cylinder body 71 from being dispersed by the gap between the outer cylinder body 71 and the mandrel 72, the sealing performance between the outer cylinder body 71 and the mandrel 72 needs to be ensured. Preferably, at least one fourth sealing ring is provided between the outer cylinder body 71 and the mandrel 72, and the fourth sealing ring is provided in the fourth sealing groove 721 on the outer peripheral surface of the mandrel 72.

[0058] Preferably, at least one fifth sealing ring can be provided between the lower joint 73 and the mandrel 72, and the fifth sealing ring is clamped in the fifth sealing groove 731 on the inner peripheral surface of the lower joint 73 to seal the gap between the lower joint 73 and the mandrel 72 and prevent it from interfering with the outer cylinder body 71 disengaging from the lower joint 73.

[0059] The specific number, structure, shape, and size of the third sealing groove 711, the fourth sealing groove 721, and the fifth sealing groove 731 are determined according to the number, structure, shape, and size of the corresponding sealing rings provided.

[0060] The material, structure and size of the third sealing ring, the fourth sealing ring and the fifth sealing ring are determined according to the sealing requirements required for actual production.

[0061] When in use, the fracturing packer in the small casing can form a "single-sealing and two-layer" pipe string by itself, or can be combined with a universal packer to form a "double-sealing and two-layer" pipe string; when the pipe string is lowered to the predetermined position, a sealing ball 20 is dropped into the wellhead, and the sealing ball 20 falls into the ball seat 74 of the lower joint 73 at the bottom of the packer, and then the pump truck is used for pressurization, and the pressure enters the hydraulic cylinder 7 through the pressure transmission hole 43 of the central pipe 4. When the pressure on the outer cylinder body 71 of the hydraulic cylinder 7 reaches a certain value, the connection between the outer cylinder body 71 and the lower joint 73 is sheared and broken, so that the outer cylinder body 71 moves upward, squeezes the slips 5 and the sealing rubber cylinder 6, and the slips 5 are stretched out under pressure to complete the sealing, and then the pump truck continues to pressurize and increase the pressure in the packer, and the sealing ball 20 and the ball seat 74 are knocked to the bottom of the well by pressure.

[0062] When fracturing the lower production layer, the fracturing fluid flows through the extension pipe 1, the sandblasting sleeve 3 and the central pipe 4 in sequence, and then enters the wellbore and the production layer. After the construction of the lower production layer is completed, the fracturing ball 10 is dropped from the wellhead. When the fracturing ball 10 reaches the sandblaster position, the fracturing ball 10 and the sandblasting sleeve 3 are pushed downward by the pump truck until the sandblasting sleeve 3 is locked with the central pipe 4 through the locking ring, so that the sandblasting port of the sandblaster body 2 is exposed to communicate with the upper production layer for fracturing.

[0063] After all the construction is completed and the blasting production stage begins, as the formation fluid flows to the ground, the blasting port of the sandblaster gradually dissolves and breaks off, and then the extension pipe 1 can be taken out through the upper pipe column, and the remaining sandblaster body 2, slips 5, sealing rubber tube 6 and hydraulic cylinder 7 are gradually dissolved, and the center pipe 4 and the sandblasting sleeve 3 fall to the bottom of the well due to loss of support.

[0064] In this embodiment, layered fracturing is achieved in the small casing, and because the sandblaster body 2, slips 5, sealing rubber tube 6 and hydraulic cylinder 7 are all soluble, the problem of unsealing the packer in the small casing is avoided, the construction cost is low, the safety is high, and the operation procedure is simple, and it can be put into production directly after the pressure is prepared.

[0065] On the basis of the above embodiments, considering that the fracturing fluid enters the center pipe 4 from the sandblasting sleeve 3, which is a sudden expansion of liquid, and reducing the damage of the sand-carrying fluid to the center pipe 4, a wear-resistant portion 41 can be provided on the upper part of the center pipe 4, and the wear-resistant portion 41 is sleeved on the inner circumferential surface of the center pipe 4, and the wear-resistant portion 41 is clamped in the limiting groove formed by the sandblaster body 2 and the sandblasting sleeve 3.

[0066] The wear-resistant portion 41 can be made of a specific alloy, which has good wear resistance, can significantly reduce the damage of the sand-carrying fluid to the central pipe 4, and effectively protect the packer.

[0067] Preferably, at least one second sealing ring is provided between the wear-resistant part 41 and the sandblasting sliding sleeve 3, and the second sealing ring is clamped in the second sealing groove 32 on the outer peripheral surface of the sandblasting sliding sleeve 3.

[0068] The specific quantities, structures, shapes, sizes, etc. of both the first sealing groove 31 and the second sealing groove 32 are determined according to the quantities, structures, shapes, and sizes of the corresponding sealing rings provided;

[0069] The materials, structures, and sizes of the first sealing ring and the second sealing ring are determined according to the sealing requirements required in actual production.

[0070] In a specific embodiment, in order to facilitate the shortening of the connection part of the packer under pressure, the sandblasting sliding sleeve 3 can slide relative to the inner peripheral surface of the sandblasting device body 2, and the sandblasting sliding sleeve 3 is connected to the sandblasting device body 2 through a shear pin 8; the outer cylinder body 71 and the lower joint 73 are connected through a shear pin 8, and the lower joint 73 and the ball seat 74 are connected through a shear pin 8.

[0071] Compared with threaded connection, the processing of the pin holes is more convenient, the processing cost is lower, and the size of the shear pin 8 is easier to check and calculate according to the preset shear stress requirements.

[0072] It should be noted that the first lock ring groove and the second lock ring groove 42 mentioned in this application document, the first sealing ring, the second sealing ring, the third sealing ring, the fourth sealing ring, and the fifth sealing ring, as well as the first, second, third, fourth, and fifth in the first sealing groove 31, the second sealing groove 32, the third sealing groove 711, the fourth sealing groove 721, and the fifth sealing groove 731 are only used to distinguish different positions and do not include the limitation of the order.

[0073] In this specification, the various embodiments are described in a progressive manner. Each embodiment focuses on the differences from other embodiments. The same or similar parts among the various embodiments can be referred to each other.

[0074] The above has introduced the small casing internal fracturing packer provided by the present utility model in detail. Specific examples are used in this article to elaborate on the principle and implementation manner of the present utility model. The description of the above embodiments is only used to help understand the method and its core idea of the present utility model. It should be pointed out that for those of ordinary skill in the art in this technical field, without departing from the principle of the present utility model, several improvements and modifications can still be made to the present utility model, and these improvements and modifications also fall within the protection scope of the claims of the present utility model.

Claims

1. A small casing internal fracturing packer, characterized in that, It includes an extended pipe (1) arranged from top to bottom, a sandblaster, a central pipe (4), and a hydraulic cylinder (7). A sealing rubber cylinder (6) and a slip (5) are sleeved outside the central pipe (4). The slip (5) is arranged between the central pipe (4) and the sealing rubber cylinder (6), and between the sealing rubber cylinder (6) and the hydraulic cylinder (7). The sandblaster includes a sandblaster body (2) and a sandblasting sliding sleeve (3) sleeved inside the sandblaster body (2). The sandblaster body (2), the slip (5), the sealing rubber cylinder (6), and the hydraulic cylinder (7) are all dissolvable. The outer peripheral surface of the sandblasting sliding sleeve (3) is provided with a first lock ring groove for installing a lock ring. The upper part of the central pipe (4) is provided with a second lock ring groove (42) for installing the lock ring. The lower part of the central pipe (4) is provided with a pressure transmission through hole (43). The hydraulic cylinder (7) includes an outer cylinder body (71), a core shaft (72), and a lower joint (73) sleeved between the outer cylinder body (71) and the core shaft (72). The core shaft (72) is connected to the lower end of the central pipe (4). The outer cylinder body (71) is connected to the lower joint (73). A ball seat (74) is sleeved at the lower end of the lower joint (73).

2. The inner-pressure fracturing packer for small casing according to claim 1, wherein, The sandblasting sliding sleeve (3) can slide relative to the inner peripheral surface of the sandblaster body (2), and the sandblasting sliding sleeve (3) is connected to the sandblaster body (2) through a shear pin (8).

3. The inner pressure fracturing packer for small casing according to claim 1, characterized in that, The upper part of the central pipe (4) is provided with a wear-resistant part (41). The wear-resistant part (41) is sleeved on the inner peripheral surface of the central pipe (4). The wear-resistant part (41) is clamped in a limiting groove formed by the sandblaster body (2) and the sandblasting sliding sleeve (3).

4. The inner casing fracturing packer according to claim 3, characterized in that, At least one second sealing ring is arranged between the wear-resistant part (41) and the sandblasting sliding sleeve (3). The second sealing ring is clamped in a second sealing groove (32) on the outer peripheral surface of the sandblasting sliding sleeve (3).

5. The inner pressure fracturing packer in a small casing according to claim 1, wherein The slip (5) includes a plurality of slip pieces arranged uniformly around the central pipe (4). The structures and sizes of the slips (5) at both ends of the sealing rubber cylinder (6) are the same.

6. The inner pressure fracturing packer for small casing according to claim 1, characterized in that, The upper end of the core shaft (72) is provided with a limiting step for abutting against the central pipe (4). The core shaft (72) is threadedly connected to the lower end of the central pipe (4).

7. The inner pressure fracturing packer for small casing according to claim 1, characterized in that, The outer cylinder body (71) and the lower joint (73) are connected through a shear pin (8). The lower joint (73) and the ball seat (74) are connected through the shear pin (8).

8. The inner pressure fracturing packer for small casing according to any one of claims 1-7, characterized in that, At least one first sealing ring is arranged between the sandblaster body (2) and the sandblasting sliding sleeve (3). The first sealing ring is clamped in a first sealing groove (31) on the outer peripheral surface of the sandblasting sliding sleeve (3).

9. The inner pressure fracturing packer in a small casing according to any one of claims 1-7, characterized in that, At least one third sealing ring is arranged between the outer cylinder body (71) and the central pipe (4). The third sealing ring is clamped in a third sealing groove (711) on the inner peripheral surface of the outer cylinder body (71).

10. The small casing internal pressure fracturing packer according to any one of claims 1-7, characterized in that, At least one fourth sealing ring is arranged between the outer cylinder body (71) and the core shaft (72). The fourth sealing ring is arranged in a fourth sealing groove (721) on the outer peripheral surface of the core shaft (72). At least one fifth sealing ring is provided between the lower sub (73) and the mandrel (72), and the fifth sealing ring is clamped in a fifth sealing groove (731) on the inner peripheral surface of the lower sub (73).

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